fs/btrfs/volumes.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/bio.h>
  20 #include <linux/slab.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/random.h>
  24 #include <linux/iocontext.h>
  25 #include <linux/capability.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/kthread.h>
  28 #include <linux/raid/pq.h>
  29 #include <linux/semaphore.h>
  30 #include <asm/div64.h>
  31 #include "ctree.h"
  32 #include "extent_map.h"
  33 #include "disk-io.h"
  34 #include "transaction.h"
  35 #include "print-tree.h"
  36 #include "volumes.h"
  37 #include "raid56.h"
  38 #include "async-thread.h"
  39 #include "check-integrity.h"
  40 #include "rcu-string.h"
  41 #include "math.h"
  42 #include "dev-replace.h"
  43 #include "sysfs.h"
  44
  45 const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
  46         [BTRFS_RAID_RAID10] = {
  47                 .sub_stripes    = 2,
  48                 .dev_stripes    = 1,
  49                 .devs_max       = 0,    /* 0 == as many as possible */
  50                 .devs_min       = 4,
  51                 .tolerated_failures = 1,
  52                 .devs_increment = 2,
  53                 .ncopies        = 2,
  54         },
  55         [BTRFS_RAID_RAID1] = {
  56                 .sub_stripes    = 1,
  57                 .dev_stripes    = 1,
  58                 .devs_max       = 2,
  59                 .devs_min       = 2,
  60                 .tolerated_failures = 1,
  61                 .devs_increment = 2,
  62                 .ncopies        = 2,
  63         },
  64         [BTRFS_RAID_DUP] = {
  65                 .sub_stripes    = 1,
  66                 .dev_stripes    = 2,
  67                 .devs_max       = 1,
  68                 .devs_min       = 1,
  69                 .tolerated_failures = 0,
  70                 .devs_increment = 1,
  71                 .ncopies        = 2,
  72         },
  73         [BTRFS_RAID_RAID0] = {
  74                 .sub_stripes    = 1,
  75                 .dev_stripes    = 1,
  76                 .devs_max       = 0,
  77                 .devs_min       = 2,
  78                 .tolerated_failures = 0,
  79                 .devs_increment = 1,
  80                 .ncopies        = 1,
  81         },
  82         [BTRFS_RAID_SINGLE] = {
  83                 .sub_stripes    = 1,
  84                 .dev_stripes    = 1,
  85                 .devs_max       = 1,
  86                 .devs_min       = 1,
  87                 .tolerated_failures = 0,
  88                 .devs_increment = 1,
  89                 .ncopies        = 1,
  90         },
  91         [BTRFS_RAID_RAID5] = {
  92                 .sub_stripes    = 1,
  93                 .dev_stripes    = 1,
  94                 .devs_max       = 0,
  95                 .devs_min       = 2,
  96                 .tolerated_failures = 1,
  97                 .devs_increment = 1,
  98                 .ncopies        = 2,
  99         },
 100         [BTRFS_RAID_RAID6] = {
 101                 .sub_stripes    = 1,
 102                 .dev_stripes    = 1,
 103                 .devs_max       = 0,
 104                 .devs_min       = 3,
 105                 .tolerated_failures = 2,
 106                 .devs_increment = 1,
 107                 .ncopies        = 3,
 108         },
 109 };
 110
 111 const u64 const btrfs_raid_group[BTRFS_NR_RAID_TYPES] = {
 112         [BTRFS_RAID_RAID10] = BTRFS_BLOCK_GROUP_RAID10,
 113         [BTRFS_RAID_RAID1]  = BTRFS_BLOCK_GROUP_RAID1,
 114         [BTRFS_RAID_DUP]    = BTRFS_BLOCK_GROUP_DUP,
 115         [BTRFS_RAID_RAID0]  = BTRFS_BLOCK_GROUP_RAID0,
 116         [BTRFS_RAID_SINGLE] = 0,
 117         [BTRFS_RAID_RAID5]  = BTRFS_BLOCK_GROUP_RAID5,
 118         [BTRFS_RAID_RAID6]  = BTRFS_BLOCK_GROUP_RAID6,
 119 };
 120
 121 static int init_first_rw_device(struct btrfs_trans_handle *trans,
 122                                 struct btrfs_root *root,
 123                                 struct btrfs_device *device);
 124 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
 125 static void __btrfs_reset_dev_stats(struct btrfs_device *dev);
 126 static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev);
 127 static void btrfs_dev_stat_print_on_load(struct btrfs_device *device);
 128 static void btrfs_close_one_device(struct btrfs_device *device);
 129
 130 DEFINE_MUTEX(uuid_mutex);
 131 static LIST_HEAD(fs_uuids);
 132 struct list_head *btrfs_get_fs_uuids(void)
 133 {
 134         return &fs_uuids;
 135 }
 136
 137 static struct btrfs_fs_devices *__alloc_fs_devices(void)
 138 {
 139         struct btrfs_fs_devices *fs_devs;
 140
 141         fs_devs = kzalloc(sizeof(*fs_devs), GFP_NOFS);
 142         if (!fs_devs)
 143                 return ERR_PTR(-ENOMEM);
 144
 145         mutex_init(&fs_devs->device_list_mutex);
 146
 147         INIT_LIST_HEAD(&fs_devs->devices);
 148         INIT_LIST_HEAD(&fs_devs->resized_devices);
 149         INIT_LIST_HEAD(&fs_devs->alloc_list);
 150         INIT_LIST_HEAD(&fs_devs->list);
 151
 152         return fs_devs;
 153 }
 154
 155 /**
 156  * alloc_fs_devices - allocate struct btrfs_fs_devices
 157  * @fsid:       a pointer to UUID for this FS.  If NULL a new UUID is
 158  *              generated.
 159  *
 160  * Return: a pointer to a new &struct btrfs_fs_devices on success;
 161  * ERR_PTR() on error.  Returned struct is not linked onto any lists and
 162  * can be destroyed with kfree() right away.
 163  */
 164 static struct btrfs_fs_devices *alloc_fs_devices(const u8 *fsid)
 165 {
 166         struct btrfs_fs_devices *fs_devs;
 167
 168         fs_devs = __alloc_fs_devices();
 169         if (IS_ERR(fs_devs))
 170                 return fs_devs;
 171
 172         if (fsid)
 173                 memcpy(fs_devs->fsid, fsid, BTRFS_FSID_SIZE);
 174         else
 175                 generate_random_uuid(fs_devs->fsid);
 176
 177         return fs_devs;
 178 }
 179
 180 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
 181 {
 182         struct btrfs_device *device;
 183         WARN_ON(fs_devices->opened);
 184         while (!list_empty(&fs_devices->devices)) {
 185                 device = list_entry(fs_devices->devices.next,
 186                                     struct btrfs_device, dev_list);
 187                 list_del(&device->dev_list);
 188                 rcu_string_free(device->name);
 189                 kfree(device);
 190         }
 191         kfree(fs_devices);
 192 }
 193
 194 static void btrfs_kobject_uevent(struct block_device *bdev,
 195                                  enum kobject_action action)
 196 {
 197         int ret;
 198
 199         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
 200         if (ret)
 201                 pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
 202                         action,
 203                         kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
 204                         &disk_to_dev(bdev->bd_disk)->kobj);
 205 }
 206
 207 void btrfs_cleanup_fs_uuids(void)
 208 {
 209         struct btrfs_fs_devices *fs_devices;
 210
 211         while (!list_empty(&fs_uuids)) {
 212                 fs_devices = list_entry(fs_uuids.next,
 213                                         struct btrfs_fs_devices, list);
 214                 list_del(&fs_devices->list);
 215                 free_fs_devices(fs_devices);
 216         }
 217 }
 218
 219 static struct btrfs_device *__alloc_device(void)
 220 {
 221         struct btrfs_device *dev;
 222
 223         dev = kzalloc(sizeof(*dev), GFP_NOFS);
 224         if (!dev)
 225                 return ERR_PTR(-ENOMEM);
 226
 227         INIT_LIST_HEAD(&dev->dev_list);
 228         INIT_LIST_HEAD(&dev->dev_alloc_list);
 229         INIT_LIST_HEAD(&dev->resized_list);
 230
 231         spin_lock_init(&dev->io_lock);
 232
 233         spin_lock_init(&dev->reada_lock);
 234         atomic_set(&dev->reada_in_flight, 0);
 235         atomic_set(&dev->dev_stats_ccnt, 0);
 236         INIT_RADIX_TREE(&dev->reada_zones, GFP_NOFS & ~__GFP_DIRECT_RECLAIM);
 237         INIT_RADIX_TREE(&dev->reada_extents, GFP_NOFS & ~__GFP_DIRECT_RECLAIM);
 238
 239         return dev;
 240 }
 241
 242 static noinline struct btrfs_device *__find_device(struct list_head *head,
 243                                                    u64 devid, u8 *uuid)
 244 {
 245         struct btrfs_device *dev;
 246
 247         list_for_each_entry(dev, head, dev_list) {
 248                 if (dev->devid == devid &&
 249                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
 250                         return dev;
 251                 }
 252         }
 253         return NULL;
 254 }
 255
 256 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
 257 {
 258         struct btrfs_fs_devices *fs_devices;
 259
 260         list_for_each_entry(fs_devices, &fs_uuids, list) {
 261                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
 262                         return fs_devices;
 263         }
 264         return NULL;
 265 }
 266
 267 static int
 268 btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder,
 269                       int flush, struct block_device **bdev,
 270                       struct buffer_head **bh)
 271 {
 272         int ret;
 273
 274         *bdev = blkdev_get_by_path(device_path, flags, holder);
 275
 276         if (IS_ERR(*bdev)) {
 277                 ret = PTR_ERR(*bdev);
 278                 goto error;
 279         }
 280
 281         if (flush)
 282                 filemap_write_and_wait((*bdev)->bd_inode->i_mapping);
 283         ret = set_blocksize(*bdev, 4096);
 284         if (ret) {
 285                 blkdev_put(*bdev, flags);
 286                 goto error;
 287         }
 288         invalidate_bdev(*bdev);
 289         *bh = btrfs_read_dev_super(*bdev);
 290         if (IS_ERR(*bh)) {
 291                 ret = PTR_ERR(*bh);
 292                 blkdev_put(*bdev, flags);
 293                 goto error;
 294         }
 295
 296         return 0;
 297
 298 error:
 299         *bdev = NULL;
 300         *bh = NULL;
 301         return ret;
 302 }
 303
 304 static void requeue_list(struct btrfs_pending_bios *pending_bios,
 305                         struct bio *head, struct bio *tail)
 306 {
 307
 308         struct bio *old_head;
 309
 310         old_head = pending_bios->head;
 311         pending_bios->head = head;
 312         if (pending_bios->tail)
 313                 tail->bi_next = old_head;
 314         else
 315                 pending_bios->tail = tail;
 316 }
 317
 318 /*
 319  * we try to collect pending bios for a device so we don't get a large
 320  * number of procs sending bios down to the same device.  This greatly
 321  * improves the schedulers ability to collect and merge the bios.
 322  *
 323  * But, it also turns into a long list of bios to process and that is sure
 324  * to eventually make the worker thread block.  The solution here is to
 325  * make some progress and then put this work struct back at the end of
 326  * the list if the block device is congested.  This way, multiple devices
 327  * can make progress from a single worker thread.
 328  */
 329 static noinline void run_scheduled_bios(struct btrfs_device *device)
 330 {
 331         struct bio *pending;
 332         struct backing_dev_info *bdi;
 333         struct btrfs_fs_info *fs_info;
 334         struct btrfs_pending_bios *pending_bios;
 335         struct bio *tail;
 336         struct bio *cur;
 337         int again = 0;
 338         unsigned long num_run;
 339         unsigned long batch_run = 0;
 340         unsigned long limit;
 341         unsigned long last_waited = 0;
 342         int force_reg = 0;
 343         int sync_pending = 0;
 344         struct blk_plug plug;
 345
 346         /*
 347          * this function runs all the bios we've collected for
 348          * a particular device.  We don't want to wander off to
 349          * another device without first sending all of these down.
 350          * So, setup a plug here and finish it off before we return
 351          */
 352         blk_start_plug(&plug);
 353
 354         bdi = blk_get_backing_dev_info(device->bdev);
 355         fs_info = device->dev_root->fs_info;
 356         limit = btrfs_async_submit_limit(fs_info);
 357         limit = limit * 2 / 3;
 358
 359 loop:
 360         spin_lock(&device->io_lock);
 361
 362 loop_lock:
 363         num_run = 0;
 364
 365         /* take all the bios off the list at once and process them
 366          * later on (without the lock held).  But, remember the
 367          * tail and other pointers so the bios can be properly reinserted
 368          * into the list if we hit congestion
 369          */
 370         if (!force_reg && device->pending_sync_bios.head) {
 371                 pending_bios = &device->pending_sync_bios;
 372                 force_reg = 1;
 373         } else {
 374                 pending_bios = &device->pending_bios;
 375                 force_reg = 0;
 376         }
 377
 378         pending = pending_bios->head;
 379         tail = pending_bios->tail;
 380         WARN_ON(pending && !tail);
 381
 382         /*
 383          * if pending was null this time around, no bios need processing
 384          * at all and we can stop.  Otherwise it'll loop back up again
 385          * and do an additional check so no bios are missed.
 386          *
 387          * device->running_pending is used to synchronize with the
 388          * schedule_bio code.
 389          */
 390         if (device->pending_sync_bios.head == NULL &&
 391             device->pending_bios.head == NULL) {
 392                 again = 0;
 393                 device->running_pending = 0;
 394         } else {
 395                 again = 1;
 396                 device->running_pending = 1;
 397         }
 398
 399         pending_bios->head = NULL;
 400         pending_bios->tail = NULL;
 401
 402         spin_unlock(&device->io_lock);
 403
 404         while (pending) {
 405
 406                 rmb();
 407                 /* we want to work on both lists, but do more bios on the
 408                  * sync list than the regular list
 409                  */
 410                 if ((num_run > 32 &&
 411                     pending_bios != &device->pending_sync_bios &&
 412                     device->pending_sync_bios.head) ||
 413                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
 414                     device->pending_bios.head)) {
 415                         spin_lock(&device->io_lock);
 416                         requeue_list(pending_bios, pending, tail);
 417                         goto loop_lock;
 418                 }
 419
 420                 cur = pending;
 421                 pending = pending->bi_next;
 422                 cur->bi_next = NULL;
 423
 424                 /*
 425                  * atomic_dec_return implies a barrier for waitqueue_active
 426                  */
 427                 if (atomic_dec_return(&fs_info->nr_async_bios) < limit &&
 428                     waitqueue_active(&fs_info->async_submit_wait))
 429                         wake_up(&fs_info->async_submit_wait);
 430
 431                 BUG_ON(atomic_read(&cur->__bi_cnt) == 0);
 432
 433                 /*
 434                  * if we're doing the sync list, record that our
 435                  * plug has some sync requests on it
 436                  *
 437                  * If we're doing the regular list and there are
 438                  * sync requests sitting around, unplug before
 439                  * we add more
 440                  */
 441                 if (pending_bios == &device->pending_sync_bios) {
 442                         sync_pending = 1;
 443                 } else if (sync_pending) {
 444                         blk_finish_plug(&plug);
 445                         blk_start_plug(&plug);
 446                         sync_pending = 0;
 447                 }
 448
 449                 btrfsic_submit_bio(cur->bi_rw, cur);
 450                 num_run++;
 451                 batch_run++;
 452
 453                 cond_resched();
 454
 455                 /*
 456                  * we made progress, there is more work to do and the bdi
 457                  * is now congested.  Back off and let other work structs
 458                  * run instead
 459                  */
 460                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
 461                     fs_info->fs_devices->open_devices > 1) {
 462                         struct io_context *ioc;
 463
 464                         ioc = current->io_context;
 465
 466                         /*
 467                          * the main goal here is that we don't want to
 468                          * block if we're going to be able to submit
 469                          * more requests without blocking.
 470                          *
 471                          * This code does two great things, it pokes into
 472                          * the elevator code from a filesystem _and_
 473                          * it makes assumptions about how batching works.
 474                          */
 475                         if (ioc && ioc->nr_batch_requests > 0 &&
 476                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
 477                             (last_waited == 0 ||
 478                              ioc->last_waited == last_waited)) {
 479                                 /*
 480                                  * we want to go through our batch of
 481                                  * requests and stop.  So, we copy out
 482                                  * the ioc->last_waited time and test
 483                                  * against it before looping
 484                                  */
 485                                 last_waited = ioc->last_waited;
 486                                 cond_resched();
 487                                 continue;
 488                         }
 489                         spin_lock(&device->io_lock);
 490                         requeue_list(pending_bios, pending, tail);
 491                         device->running_pending = 1;
 492
 493                         spin_unlock(&device->io_lock);
 494                         btrfs_queue_work(fs_info->submit_workers,
 495                                          &device->work);
 496                         goto done;
 497                 }
 498                 /* unplug every 64 requests just for good measure */
 499                 if (batch_run % 64 == 0) {
 500                         blk_finish_plug(&plug);
 501                         blk_start_plug(&plug);
 502                         sync_pending = 0;
 503                 }
 504         }
 505
 506         cond_resched();
 507         if (again)
 508                 goto loop;
 509
 510         spin_lock(&device->io_lock);
 511         if (device->pending_bios.head || device->pending_sync_bios.head)
 512                 goto loop_lock;
 513         spin_unlock(&device->io_lock);
 514
 515 done:
 516         blk_finish_plug(&plug);
 517 }
 518
 519 static void pending_bios_fn(struct btrfs_work *work)
 520 {
 521         struct btrfs_device *device;
 522
 523         device = container_of(work, struct btrfs_device, work);
 524         run_scheduled_bios(device);
 525 }
 526
 527
 528 void btrfs_free_stale_device(struct btrfs_device *cur_dev)
 529 {
 530         struct btrfs_fs_devices *fs_devs;
 531         struct btrfs_device *dev;
 532
 533         if (!cur_dev->name)
 534                 return;
 535
 536         list_for_each_entry(fs_devs, &fs_uuids, list) {
 537                 int del = 1;
 538
 539                 if (fs_devs->opened)
 540                         continue;
 541                 if (fs_devs->seeding)
 542                         continue;
 543
 544                 list_for_each_entry(dev, &fs_devs->devices, dev_list) {
 545
 546                         if (dev == cur_dev)
 547                                 continue;
 548                         if (!dev->name)
 549                                 continue;
 550
 551                         /*
 552                          * Todo: This won't be enough. What if the same device
 553                          * comes back (with new uuid and) with its mapper path?
 554                          * But for now, this does help as mostly an admin will
 555                          * either use mapper or non mapper path throughout.
 556                          */
 557                         rcu_read_lock();
 558                         del = strcmp(rcu_str_deref(dev->name),
 559                                                 rcu_str_deref(cur_dev->name));
 560                         rcu_read_unlock();
 561                         if (!del)
 562                                 break;
 563                 }
 564
 565                 if (!del) {
 566                         /* delete the stale device */
 567                         if (fs_devs->num_devices == 1) {
 568                                 btrfs_sysfs_remove_fsid(fs_devs);
 569                                 list_del(&fs_devs->list);
 570                                 free_fs_devices(fs_devs);
 571                         } else {
 572                                 fs_devs->num_devices--;
 573                                 list_del(&dev->dev_list);
 574                                 rcu_string_free(dev->name);
 575                                 kfree(dev);
 576                         }
 577                         break;
 578                 }
 579         }
 580 }
 581
 582 /*
 583  * Add new device to list of registered devices
 584  *
 585  * Returns:
 586  * 1   - first time device is seen
 587  * 0   - device already known
 588  * < 0 - error
 589  */
 590 static noinline int device_list_add(const char *path,
 591                            struct btrfs_super_block *disk_super,
 592                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
 593 {
 594         struct btrfs_device *device;
 595         struct btrfs_fs_devices *fs_devices;
 596         struct rcu_string *name;
 597         int ret = 0;
 598         u64 found_transid = btrfs_super_generation(disk_super);
 599
 600         fs_devices = find_fsid(disk_super->fsid);
 601         if (!fs_devices) {
 602                 fs_devices = alloc_fs_devices(disk_super->fsid);
 603                 if (IS_ERR(fs_devices))
 604                         return PTR_ERR(fs_devices);
 605
 606                 list_add(&fs_devices->list, &fs_uuids);
 607
 608                 device = NULL;
 609         } else {
 610                 device = __find_device(&fs_devices->devices, devid,
 611                                        disk_super->dev_item.uuid);
 612         }
 613
 614         if (!device) {
 615                 if (fs_devices->opened)
 616                         return -EBUSY;
 617
 618                 device = btrfs_alloc_device(NULL, &devid,
 619                                             disk_super->dev_item.uuid);
 620                 if (IS_ERR(device)) {
 621                         /* we can safely leave the fs_devices entry around */
 622                         return PTR_ERR(device);
 623                 }
 624
 625                 name = rcu_string_strdup(path, GFP_NOFS);
 626                 if (!name) {
 627                         kfree(device);
 628                         return -ENOMEM;
 629                 }
 630                 rcu_assign_pointer(device->name, name);
 631
 632                 mutex_lock(&fs_devices->device_list_mutex);
 633                 list_add_rcu(&device->dev_list, &fs_devices->devices);
 634                 fs_devices->num_devices++;
 635                 mutex_unlock(&fs_devices->device_list_mutex);
 636
 637                 ret = 1;
 638                 device->fs_devices = fs_devices;
 639         } else if (!device->name || strcmp(device->name->str, path)) {
 640                 /*
 641                  * When FS is already mounted.
 642                  * 1. If you are here and if the device->name is NULL that
 643                  *    means this device was missing at time of FS mount.
 644                  * 2. If you are here and if the device->name is different
 645                  *    from 'path' that means either
 646                  *      a. The same device disappeared and reappeared with
 647                  *         different name. or
 648                  *      b. The missing-disk-which-was-replaced, has
 649                  *         reappeared now.
 650                  *
 651                  * We must allow 1 and 2a above. But 2b would be a spurious
 652                  * and unintentional.
 653                  *
 654                  * Further in case of 1 and 2a above, the disk at 'path'
 655                  * would have missed some transaction when it was away and
 656                  * in case of 2a the stale bdev has to be updated as well.
 657                  * 2b must not be allowed at all time.
 658                  */
 659
 660                 /*
 661                  * For now, we do allow update to btrfs_fs_device through the
 662                  * btrfs dev scan cli after FS has been mounted.  We're still
 663                  * tracking a problem where systems fail mount by subvolume id
 664                  * when we reject replacement on a mounted FS.
 665                  */
 666                 if (!fs_devices->opened && found_transid < device->generation) {
 667                         /*
 668                          * That is if the FS is _not_ mounted and if you
 669                          * are here, that means there is more than one
 670                          * disk with same uuid and devid.We keep the one
 671                          * with larger generation number or the last-in if
 672                          * generation are equal.
 673                          */
 674                         return -EEXIST;
 675                 }
 676
 677                 name = rcu_string_strdup(path, GFP_NOFS);
 678                 if (!name)
 679                         return -ENOMEM;
 680                 rcu_string_free(device->name);
 681                 rcu_assign_pointer(device->name, name);
 682                 if (device->missing) {
 683                         fs_devices->missing_devices--;
 684                         device->missing = 0;
 685                 }
 686         }
 687
 688         /*
 689          * Unmount does not free the btrfs_device struct but would zero
 690          * generation along with most of the other members. So just update
 691          * it back. We need it to pick the disk with largest generation
 692          * (as above).
 693          */
 694         if (!fs_devices->opened)
 695                 device->generation = found_transid;
 696
 697         /*
 698          * if there is new btrfs on an already registered device,
 699          * then remove the stale device entry.
 700          */
 701         btrfs_free_stale_device(device);
 702
 703         *fs_devices_ret = fs_devices;
 704
 705         return ret;
 706 }
 707
 708 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
 709 {
 710         struct btrfs_fs_devices *fs_devices;
 711         struct btrfs_device *device;
 712         struct btrfs_device *orig_dev;
 713
 714         fs_devices = alloc_fs_devices(orig->fsid);
 715         if (IS_ERR(fs_devices))
 716                 return fs_devices;
 717
 718         mutex_lock(&orig->device_list_mutex);
 719         fs_devices->total_devices = orig->total_devices;
 720
 721         /* We have held the volume lock, it is safe to get the devices. */
 722         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
 723                 struct rcu_string *name;
 724
 725                 device = btrfs_alloc_device(NULL, &orig_dev->devid,
 726                                             orig_dev->uuid);
 727                 if (IS_ERR(device))
 728                         goto error;
 729
 730                 /*
 731                  * This is ok to do without rcu read locked because we hold the
 732                  * uuid mutex so nothing we touch in here is going to disappear.
 733                  */
 734                 if (orig_dev->name) {
 735                         name = rcu_string_strdup(orig_dev->name->str, GFP_NOFS);
 736                         if (!name) {
 737                                 kfree(device);
 738                                 goto error;
 739                         }
 740                         rcu_assign_pointer(device->name, name);
 741                 }
 742
 743                 list_add(&device->dev_list, &fs_devices->devices);
 744                 device->fs_devices = fs_devices;
 745                 fs_devices->num_devices++;
 746         }
 747         mutex_unlock(&orig->device_list_mutex);
 748         return fs_devices;
 749 error:
 750         mutex_unlock(&orig->device_list_mutex);
 751         free_fs_devices(fs_devices);
 752         return ERR_PTR(-ENOMEM);
 753 }
 754
 755 void btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices, int step)
 756 {
 757         struct btrfs_device *device, *next;
 758         struct btrfs_device *latest_dev = NULL;
 759
 760         mutex_lock(&uuid_mutex);
 761 again:
 762         /* This is the initialized path, it is safe to release the devices. */
 763         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
 764                 if (device->in_fs_metadata) {
 765                         if (!device->is_tgtdev_for_dev_replace &&
 766                             (!latest_dev ||
 767                              device->generation > latest_dev->generation)) {
 768                                 latest_dev = device;
 769                         }
 770                         continue;
 771                 }
 772
 773                 if (device->devid == BTRFS_DEV_REPLACE_DEVID) {
 774                         /*
 775                          * In the first step, keep the device which has
 776                          * the correct fsid and the devid that is used
 777                          * for the dev_replace procedure.
 778                          * In the second step, the dev_replace state is
 779                          * read from the device tree and it is known
 780                          * whether the procedure is really active or
 781                          * not, which means whether this device is
 782                          * used or whether it should be removed.
 783                          */
 784                         if (step == 0 || device->is_tgtdev_for_dev_replace) {
 785                                 continue;
 786                         }
 787                 }
 788                 if (device->bdev) {
 789                         blkdev_put(device->bdev, device->mode);
 790                         device->bdev = NULL;
 791                         fs_devices->open_devices--;
 792                 }
 793                 if (device->writeable) {
 794                         list_del_init(&device->dev_alloc_list);
 795                         device->writeable = 0;
 796                         if (!device->is_tgtdev_for_dev_replace)
 797                                 fs_devices->rw_devices--;
 798                 }
 799                 list_del_init(&device->dev_list);
 800                 fs_devices->num_devices--;
 801                 rcu_string_free(device->name);
 802                 kfree(device);
 803         }
 804
 805         if (fs_devices->seed) {
 806                 fs_devices = fs_devices->seed;
 807                 goto again;
 808         }
 809
 810         fs_devices->latest_bdev = latest_dev->bdev;
 811
 812         mutex_unlock(&uuid_mutex);
 813 }
 814
 815 static void __free_device(struct work_struct *work)
 816 {
 817         struct btrfs_device *device;
 818
 819         device = container_of(work, struct btrfs_device, rcu_work);
 820
 821         if (device->bdev)
 822                 blkdev_put(device->bdev, device->mode);
 823
 824         rcu_string_free(device->name);
 825         kfree(device);
 826 }
 827
 828 static void free_device(struct rcu_head *head)
 829 {
 830         struct btrfs_device *device;
 831
 832         device = container_of(head, struct btrfs_device, rcu);
 833
 834         INIT_WORK(&device->rcu_work, __free_device);
 835         schedule_work(&device->rcu_work);
 836 }
 837
 838 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 839 {
 840         struct btrfs_device *device, *tmp;
 841
 842         if (--fs_devices->opened > 0)
 843                 return 0;
 844
 845         mutex_lock(&fs_devices->device_list_mutex);
 846         list_for_each_entry_safe(device, tmp, &fs_devices->devices, dev_list) {
 847                 btrfs_close_one_device(device);
 848         }
 849         mutex_unlock(&fs_devices->device_list_mutex);
 850
 851         WARN_ON(fs_devices->open_devices);
 852         WARN_ON(fs_devices->rw_devices);
 853         fs_devices->opened = 0;
 854         fs_devices->seeding = 0;
 855
 856         return 0;
 857 }
 858
 859 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 860 {
 861         struct btrfs_fs_devices *seed_devices = NULL;
 862         int ret;
 863
 864         mutex_lock(&uuid_mutex);
 865         ret = __btrfs_close_devices(fs_devices);
 866         if (!fs_devices->opened) {
 867                 seed_devices = fs_devices->seed;
 868                 fs_devices->seed = NULL;
 869         }
 870         mutex_unlock(&uuid_mutex);
 871
 872         while (seed_devices) {
 873                 fs_devices = seed_devices;
 874                 seed_devices = fs_devices->seed;
 875                 __btrfs_close_devices(fs_devices);
 876                 free_fs_devices(fs_devices);
 877         }
 878         /*
 879          * Wait for rcu kworkers under __btrfs_close_devices
 880          * to finish all blkdev_puts so device is really
 881          * free when umount is done.
 882          */
 883         rcu_barrier();
 884         return ret;
 885 }
 886
 887 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 888                                 fmode_t flags, void *holder)
 889 {
 890         struct request_queue *q;
 891         struct block_device *bdev;
 892         struct list_head *head = &fs_devices->devices;
 893         struct btrfs_device *device;
 894         struct btrfs_device *latest_dev = NULL;
 895         struct buffer_head *bh;
 896         struct btrfs_super_block *disk_super;
 897         u64 devid;
 898         int seeding = 1;
 899         int ret = 0;
 900
 901         flags |= FMODE_EXCL;
 902
 903         list_for_each_entry(device, head, dev_list) {
 904                 if (device->bdev)
 905                         continue;
 906                 if (!device->name)
 907                         continue;
 908
 909                 /* Just open everything we can; ignore failures here */
 910                 if (btrfs_get_bdev_and_sb(device->name->str, flags, holder, 1,
 911                                             &bdev, &bh))
 912                         continue;
 913
 914                 disk_super = (struct btrfs_super_block *)bh->b_data;
 915                 devid = btrfs_stack_device_id(&disk_super->dev_item);
 916                 if (devid != device->devid)
 917                         goto error_brelse;
 918
 919                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
 920                            BTRFS_UUID_SIZE))
 921                         goto error_brelse;
 922
 923                 device->generation = btrfs_super_generation(disk_super);
 924                 if (!latest_dev ||
 925                     device->generation > latest_dev->generation)
 926                         latest_dev = device;
 927
 928                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
 929                         device->writeable = 0;
 930                 } else {
 931                         device->writeable = !bdev_read_only(bdev);
 932                         seeding = 0;
 933                 }
 934
 935                 q = bdev_get_queue(bdev);
 936                 if (blk_queue_discard(q))
 937                         device->can_discard = 1;
 938
 939                 device->bdev = bdev;
 940                 device->in_fs_metadata = 0;
 941                 device->mode = flags;
 942
 943                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
 944                         fs_devices->rotating = 1;
 945
 946                 fs_devices->open_devices++;
 947                 if (device->writeable &&
 948                     device->devid != BTRFS_DEV_REPLACE_DEVID) {
 949                         fs_devices->rw_devices++;
 950                         list_add(&device->dev_alloc_list,
 951                                  &fs_devices->alloc_list);
 952                 }
 953                 brelse(bh);
 954                 continue;
 955
 956 error_brelse:
 957                 brelse(bh);
 958                 blkdev_put(bdev, flags);
 959                 continue;
 960         }
 961         if (fs_devices->open_devices == 0) {
 962                 ret = -EINVAL;
 963                 goto out;
 964         }
 965         fs_devices->seeding = seeding;
 966         fs_devices->opened = 1;
 967         fs_devices->latest_bdev = latest_dev->bdev;
 968         fs_devices->total_rw_bytes = 0;
 969 out:
 970         return ret;
 971 }
 972
 973 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 974                        fmode_t flags, void *holder)
 975 {
 976         int ret;
 977
 978         mutex_lock(&uuid_mutex);
 979         if (fs_devices->opened) {
 980                 fs_devices->opened++;
 981                 ret = 0;
 982         } else {
 983                 ret = __btrfs_open_devices(fs_devices, flags, holder);
 984         }
 985         mutex_unlock(&uuid_mutex);
 986         return ret;
 987 }
 988
 989 /*
 990  * Look for a btrfs signature on a device. This may be called out of the mount path
 991  * and we are not allowed to call set_blocksize during the scan. The superblock
 992  * is read via pagecache
 993  */
 994 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 995                           struct btrfs_fs_devices **fs_devices_ret)
 996 {
 997         struct btrfs_super_block *disk_super;
 998         struct block_device *bdev;
 999         struct page *page;
1000         void *p;
1001         int ret = -EINVAL;
1002         u64 devid;
1003         u64 transid;
1004         u64 total_devices;
1005         u64 bytenr;
1006         pgoff_t index;
1007
1008         /*
1009          * we would like to check all the supers, but that would make
1010          * a btrfs mount succeed after a mkfs from a different FS.
1011          * So, we need to add a special mount option to scan for
1012          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
1013          */
1014         bytenr = btrfs_sb_offset(0);
1015         flags |= FMODE_EXCL;
1016         mutex_lock(&uuid_mutex);
1017
1018         bdev = blkdev_get_by_path(path, flags, holder);
1019
1020         if (IS_ERR(bdev)) {
1021                 ret = PTR_ERR(bdev);
1022                 goto error;
1023         }
1024
1025         /* make sure our super fits in the device */
1026         if (bytenr + PAGE_CACHE_SIZE >= i_size_read(bdev->bd_inode))
1027                 goto error_bdev_put;
1028
1029         /* make sure our super fits in the page */
1030         if (sizeof(*disk_super) > PAGE_CACHE_SIZE)
1031                 goto error_bdev_put;
1032
1033         /* make sure our super doesn't straddle pages on disk */
1034         index = bytenr >> PAGE_CACHE_SHIFT;
1035         if ((bytenr + sizeof(*disk_super) - 1) >> PAGE_CACHE_SHIFT != index)
1036                 goto error_bdev_put;
1037
1038         /* pull in the page with our super */
1039         page = read_cache_page_gfp(bdev->bd_inode->i_mapping,
1040                                    index, GFP_NOFS);
1041
1042         if (IS_ERR_OR_NULL(page))
1043                 goto error_bdev_put;
1044
1045         p = kmap(page);
1046
1047         /* align our pointer to the offset of the super block */
1048         disk_super = p + (bytenr & ~PAGE_CACHE_MASK);
1049
1050         if (btrfs_super_bytenr(disk_super) != bytenr ||
1051             btrfs_super_magic(disk_super) != BTRFS_MAGIC)
1052                 goto error_unmap;
1053
1054         devid = btrfs_stack_device_id(&disk_super->dev_item);
1055         transid = btrfs_super_generation(disk_super);
1056         total_devices = btrfs_super_num_devices(disk_super);
1057
1058         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
1059         if (ret > 0) {
1060                 if (disk_super->label[0]) {
1061                         if (disk_super->label[BTRFS_LABEL_SIZE - 1])
1062                                 disk_super->label[BTRFS_LABEL_SIZE - 1] = '\0';
1063                         printk(KERN_INFO "BTRFS: device label %s ", disk_super->label);
1064                 } else {
1065                         printk(KERN_INFO "BTRFS: device fsid %pU ", disk_super->fsid);
1066                 }
1067
1068                 printk(KERN_CONT "devid %llu transid %llu %s\n", devid, transid, path);
1069                 ret = 0;
1070         }
1071         if (!ret && fs_devices_ret)
1072                 (*fs_devices_ret)->total_devices = total_devices;
1073
1074 error_unmap:
1075         kunmap(page);
1076         page_cache_release(page);
1077
1078 error_bdev_put:
1079         blkdev_put(bdev, flags);
1080 error:
1081         mutex_unlock(&uuid_mutex);
1082         return ret;
1083 }
1084
1085 /* helper to account the used device space in the range */
1086 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
1087                                    u64 end, u64 *length)
1088 {
1089         struct btrfs_key key;
1090         struct btrfs_root *root = device->dev_root;
1091         struct btrfs_dev_extent *dev_extent;
1092         struct btrfs_path *path;
1093         u64 extent_end;
1094         int ret;
1095         int slot;
1096         struct extent_buffer *l;
1097
1098         *length = 0;
1099
1100         if (start >= device->total_bytes || device->is_tgtdev_for_dev_replace)
1101                 return 0;
1102
1103         path = btrfs_alloc_path();
1104         if (!path)
1105                 return -ENOMEM;
1106         path->reada = READA_FORWARD;
1107
1108         key.objectid = device->devid;
1109         key.offset = start;
1110         key.type = BTRFS_DEV_EXTENT_KEY;
1111
1112         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1113         if (ret < 0)
1114                 goto out;
1115         if (ret > 0) {
1116                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
1117                 if (ret < 0)
1118                         goto out;
1119         }
1120
1121         while (1) {
1122                 l = path->nodes[0];
1123                 slot = path->slots[0];
1124                 if (slot >= btrfs_header_nritems(l)) {
1125                         ret = btrfs_next_leaf(root, path);
1126                         if (ret == 0)
1127                                 continue;
1128                         if (ret < 0)
1129                                 goto out;
1130
1131                         break;
1132                 }
1133                 btrfs_item_key_to_cpu(l, &key, slot);
1134
1135                 if (key.objectid < device->devid)
1136                         goto next;
1137
1138                 if (key.objectid > device->devid)
1139                         break;
1140
1141                 if (key.type != BTRFS_DEV_EXTENT_KEY)
1142                         goto next;
1143
1144                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1145                 extent_end = key.offset + btrfs_dev_extent_length(l,
1146                                                                   dev_extent);
1147                 if (key.offset <= start && extent_end > end) {
1148                         *length = end - start + 1;
1149                         break;
1150                 } else if (key.offset <= start && extent_end > start)
1151                         *length += extent_end - start;
1152                 else if (key.offset > start && extent_end <= end)
1153                         *length += extent_end - key.offset;
1154                 else if (key.offset > start && key.offset <= end) {
1155                         *length += end - key.offset + 1;
1156                         break;
1157                 } else if (key.offset > end)
1158                         break;
1159
1160 next:
1161                 path->slots[0]++;
1162         }
1163         ret = 0;
1164 out:
1165         btrfs_free_path(path);
1166         return ret;
1167 }
1168
1169 static int contains_pending_extent(struct btrfs_transaction *transaction,
1170                                    struct btrfs_device *device,
1171                                    u64 *start, u64 len)
1172 {
1173         struct btrfs_fs_info *fs_info = device->dev_root->fs_info;
1174         struct extent_map *em;
1175         struct list_head *search_list = &fs_info->pinned_chunks;
1176         int ret = 0;
1177         u64 physical_start = *start;
1178
1179         if (transaction)
1180                 search_list = &transaction->pending_chunks;
1181 again:
1182         list_for_each_entry(em, search_list, list) {
1183                 struct map_lookup *map;
1184                 int i;
1185
1186                 map = (struct map_lookup *)em->bdev;
1187                 for (i = 0; i < map->num_stripes; i++) {
1188                         u64 end;
1189
1190                         if (map->stripes[i].dev != device)
1191                                 continue;
1192                         if (map->stripes[i].physical >= physical_start + len ||
1193                             map->stripes[i].physical + em->orig_block_len <=
1194                             physical_start)
1195                                 continue;
1196                         /*
1197                          * Make sure that while processing the pinned list we do
1198                          * not override our *start with a lower value, because
1199                          * we can have pinned chunks that fall within this
1200                          * device hole and that have lower physical addresses
1201                          * than the pending chunks we processed before. If we
1202                          * do not take this special care we can end up getting
1203                          * 2 pending chunks that start at the same physical
1204                          * device offsets because the end offset of a pinned
1205                          * chunk can be equal to the start offset of some
1206                          * pending chunk.
1207                          */
1208                         end = map->stripes[i].physical + em->orig_block_len;
1209                         if (end > *start) {
1210                                 *start = end;
1211                                 ret = 1;
1212                         }
1213                 }
1214         }
1215         if (search_list != &fs_info->pinned_chunks) {
1216                 search_list = &fs_info->pinned_chunks;
1217                 goto again;
1218         }
1219
1220         return ret;
1221 }
1222
1223
1224 /*
1225  * find_free_dev_extent_start - find free space in the specified device
1226  * @device:       the device which we search the free space in
1227  * @num_bytes:    the size of the free space that we need
1228  * @search_start: the position from which to begin the search
1229  * @start:        store the start of the free space.
1230  * @len:          the size of the free space. that we find, or the size
1231  *                of the max free space if we don't find suitable free space
1232  *
1233  * this uses a pretty simple search, the expectation is that it is
1234  * called very infrequently and that a given device has a small number
1235  * of extents
1236  *
1237  * @start is used to store the start of the free space if we find. But if we
1238  * don't find suitable free space, it will be used to store the start position
1239  * of the max free space.
1240  *
1241  * @len is used to store the size of the free space that we find.
1242  * But if we don't find suitable free space, it is used to store the size of
1243  * the max free space.
1244  */
1245 int find_free_dev_extent_start(struct btrfs_transaction *transaction,
1246                                struct btrfs_device *device, u64 num_bytes,
1247                                u64 search_start, u64 *start, u64 *len)
1248 {
1249         struct btrfs_key key;
1250         struct btrfs_root *root = device->dev_root;
1251         struct btrfs_dev_extent *dev_extent;
1252         struct btrfs_path *path;
1253         u64 hole_size;
1254         u64 max_hole_start;
1255         u64 max_hole_size;
1256         u64 extent_end;
1257         u64 search_end = device->total_bytes;
1258         int ret;
1259         int slot;
1260         struct extent_buffer *l;
1261         u64 min_search_start;
1262
1263         /*
1264          * We don't want to overwrite the superblock on the drive nor any area
1265          * used by the boot loader (grub for example), so we make sure to start
1266          * at an offset of at least 1MB.
1267          */
1268         min_search_start = max(root->fs_info->alloc_start, 1024ull * 1024);
1269         search_start = max(search_start, min_search_start);
1270
1271         path = btrfs_alloc_path();
1272         if (!path)
1273                 return -ENOMEM;
1274
1275         max_hole_start = search_start;
1276         max_hole_size = 0;
1277
1278 again:
1279         if (search_start >= search_end || device->is_tgtdev_for_dev_replace) {
1280                 ret = -ENOSPC;
1281                 goto out;
1282         }
1283
1284         path->reada = READA_FORWARD;
1285         path->search_commit_root = 1;
1286         path->skip_locking = 1;
1287
1288         key.objectid = device->devid;
1289         key.offset = search_start;
1290         key.type = BTRFS_DEV_EXTENT_KEY;
1291
1292         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1293         if (ret < 0)
1294                 goto out;
1295         if (ret > 0) {
1296                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
1297                 if (ret < 0)
1298                         goto out;
1299         }
1300
1301         while (1) {
1302                 l = path->nodes[0];
1303                 slot = path->slots[0];
1304                 if (slot >= btrfs_header_nritems(l)) {
1305                         ret = btrfs_next_leaf(root, path);
1306                         if (ret == 0)
1307                                 continue;
1308                         if (ret < 0)
1309                                 goto out;
1310
1311                         break;
1312                 }
1313                 btrfs_item_key_to_cpu(l, &key, slot);
1314
1315                 if (key.objectid < device->devid)
1316                         goto next;
1317
1318                 if (key.objectid > device->devid)
1319                         break;
1320
1321                 if (key.type != BTRFS_DEV_EXTENT_KEY)
1322                         goto next;
1323
1324                 if (key.offset > search_start) {
1325                         hole_size = key.offset - search_start;
1326
1327                         /*
1328                          * Have to check before we set max_hole_start, otherwise
1329                          * we could end up sending back this offset anyway.
1330                          */
1331                         if (contains_pending_extent(transaction, device,
1332                                                     &search_start,
1333                                                     hole_size)) {
1334                                 if (key.offset >= search_start) {
1335                                         hole_size = key.offset - search_start;
1336                                 } else {
1337                                         WARN_ON_ONCE(1);
1338                                         hole_size = 0;
1339                                 }
1340                         }
1341
1342                         if (hole_size > max_hole_size) {
1343                                 max_hole_start = search_start;
1344                                 max_hole_size = hole_size;
1345                         }
1346
1347                         /*
1348                          * If this free space is greater than which we need,
1349                          * it must be the max free space that we have found
1350                          * until now, so max_hole_start must point to the start
1351                          * of this free space and the length of this free space
1352                          * is stored in max_hole_size. Thus, we return
1353                          * max_hole_start and max_hole_size and go back to the
1354                          * caller.
1355                          */
1356                         if (hole_size >= num_bytes) {
1357                                 ret = 0;
1358                                 goto out;
1359                         }
1360                 }
1361
1362                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1363                 extent_end = key.offset + btrfs_dev_extent_length(l,
1364                                                                   dev_extent);
1365                 if (extent_end > search_start)
1366                         search_start = extent_end;
1367 next:
1368                 path->slots[0]++;
1369                 cond_resched();
1370         }
1371
1372         /*
1373          * At this point, search_start should be the end of
1374          * allocated dev extents, and when shrinking the device,
1375          * search_end may be smaller than search_start.
1376          */
1377         if (search_end > search_start) {
1378                 hole_size = search_end - search_start;
1379
1380                 if (contains_pending_extent(transaction, device, &search_start,
1381                                             hole_size)) {
1382                         btrfs_release_path(path);
1383                         goto again;
1384                 }
1385
1386                 if (hole_size > max_hole_size) {
1387                         max_hole_start = search_start;
1388                         max_hole_size = hole_size;
1389                 }
1390         }
1391
1392         /* See above. */
1393         if (max_hole_size < num_bytes)
1394                 ret = -ENOSPC;
1395         else
1396                 ret = 0;
1397
1398 out:
1399         btrfs_free_path(path);
1400         *start = max_hole_start;
1401         if (len)
1402                 *len = max_hole_size;
1403         return ret;
1404 }
1405
1406 int find_free_dev_extent(struct btrfs_trans_handle *trans,
1407                          struct btrfs_device *device, u64 num_bytes,
1408                          u64 *start, u64 *len)
1409 {
1410         /* FIXME use last free of some kind */
1411         return find_free_dev_extent_start(trans->transaction, device,
1412                                           num_bytes, 0, start, len);
1413 }
1414
1415 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
1416                           struct btrfs_device *device,
1417                           u64 start, u64 *dev_extent_len)
1418 {
1419         int ret;
1420         struct btrfs_path *path;
1421         struct btrfs_root *root = device->dev_root;
1422         struct btrfs_key key;
1423         struct btrfs_key found_key;
1424         struct extent_buffer *leaf = NULL;
1425         struct btrfs_dev_extent *extent = NULL;
1426
1427         path = btrfs_alloc_path();
1428         if (!path)
1429                 return -ENOMEM;
1430
1431         key.objectid = device->devid;
1432         key.offset = start;
1433         key.type = BTRFS_DEV_EXTENT_KEY;
1434 again:
1435         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1436         if (ret > 0) {
1437                 ret = btrfs_previous_item(root, path, key.objectid,
1438                                           BTRFS_DEV_EXTENT_KEY);
1439                 if (ret)
1440                         goto out;
1441                 leaf = path->nodes[0];
1442                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1443                 extent = btrfs_item_ptr(leaf, path->slots[0],
1444                                         struct btrfs_dev_extent);
1445                 BUG_ON(found_key.offset > start || found_key.offset +
1446                        btrfs_dev_extent_length(leaf, extent) < start);
1447                 key = found_key;
1448                 btrfs_release_path(path);
1449                 goto again;
1450         } else if (ret == 0) {
1451                 leaf = path->nodes[0];
1452                 extent = btrfs_item_ptr(leaf, path->slots[0],
1453                                         struct btrfs_dev_extent);
1454         } else {
1455                 btrfs_std_error(root->fs_info, ret, "Slot search failed");
1456                 goto out;
1457         }
1458
1459         *dev_extent_len = btrfs_dev_extent_length(leaf, extent);
1460
1461         ret = btrfs_del_item(trans, root, path);
1462         if (ret) {
1463                 btrfs_std_error(root->fs_info, ret,
1464                             "Failed to remove dev extent item");
1465         } else {
1466                 set_bit(BTRFS_TRANS_HAVE_FREE_BGS, &trans->transaction->flags);
1467         }
1468 out:
1469         btrfs_free_path(path);
1470         return ret;
1471 }
1472
1473 static int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
1474                                   struct btrfs_device *device,
1475                                   u64 chunk_tree, u64 chunk_objectid,
1476                                   u64 chunk_offset, u64 start, u64 num_bytes)
1477 {
1478         int ret;
1479         struct btrfs_path *path;
1480         struct btrfs_root *root = device->dev_root;
1481         struct btrfs_dev_extent *extent;
1482         struct extent_buffer *leaf;
1483         struct btrfs_key key;
1484
1485         WARN_ON(!device->in_fs_metadata);
1486         WARN_ON(device->is_tgtdev_for_dev_replace);
1487         path = btrfs_alloc_path();
1488         if (!path)
1489                 return -ENOMEM;
1490
1491         key.objectid = device->devid;
1492         key.offset = start;
1493         key.type = BTRFS_DEV_EXTENT_KEY;
1494         ret = btrfs_insert_empty_item(trans, root, path, &key,
1495                                       sizeof(*extent));
1496         if (ret)
1497                 goto out;
1498
1499         leaf = path->nodes[0];
1500         extent = btrfs_item_ptr(leaf, path->slots[0],
1501                                 struct btrfs_dev_extent);
1502         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
1503         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
1504         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
1505
1506         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
1507                     btrfs_dev_extent_chunk_tree_uuid(extent), BTRFS_UUID_SIZE);
1508
1509         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
1510         btrfs_mark_buffer_dirty(leaf);
1511 out:
1512         btrfs_free_path(path);
1513         return ret;
1514 }
1515
1516 static u64 find_next_chunk(struct btrfs_fs_info *fs_info)
1517 {
1518         struct extent_map_tree *em_tree;
1519         struct extent_map *em;
1520         struct rb_node *n;
1521         u64 ret = 0;
1522
1523         em_tree = &fs_info->mapping_tree.map_tree;
1524         read_lock(&em_tree->lock);
1525         n = rb_last(&em_tree->map);
1526         if (n) {
1527                 em = rb_entry(n, struct extent_map, rb_node);
1528                 ret = em->start + em->len;
1529         }
1530         read_unlock(&em_tree->lock);
1531
1532         return ret;
1533 }
1534
1535 static noinline int find_next_devid(struct btrfs_fs_info *fs_info,
1536                                     u64 *devid_ret)
1537 {
1538         int ret;
1539         struct btrfs_key key;
1540         struct btrfs_key found_key;
1541         struct btrfs_path *path;
1542
1543         path = btrfs_alloc_path();
1544         if (!path)
1545                 return -ENOMEM;
1546
1547         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1548         key.type = BTRFS_DEV_ITEM_KEY;
1549         key.offset = (u64)-1;
1550
1551         ret = btrfs_search_slot(NULL, fs_info->chunk_root, &key, path, 0, 0);
1552         if (ret < 0)
1553                 goto error;
1554
1555         BUG_ON(ret == 0); /* Corruption */
1556
1557         ret = btrfs_previous_item(fs_info->chunk_root, path,
1558                                   BTRFS_DEV_ITEMS_OBJECTID,
1559                                   BTRFS_DEV_ITEM_KEY);
1560         if (ret) {
1561                 *devid_ret = 1;
1562         } else {
1563                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1564                                       path->slots[0]);
1565                 *devid_ret = found_key.offset + 1;
1566         }
1567         ret = 0;
1568 error:
1569         btrfs_free_path(path);
1570         return ret;
1571 }
1572
1573 /*
1574  * the device information is stored in the chunk root
1575  * the btrfs_device struct should be fully filled in
1576  */
1577 static int btrfs_add_device(struct btrfs_trans_handle *trans,
1578                             struct btrfs_root *root,
1579                             struct btrfs_device *device)
1580 {
1581         int ret;
1582         struct btrfs_path *path;
1583         struct btrfs_dev_item *dev_item;
1584         struct extent_buffer *leaf;
1585         struct btrfs_key key;
1586         unsigned long ptr;
1587
1588         root = root->fs_info->chunk_root;
1589
1590         path = btrfs_alloc_path();
1591         if (!path)
1592                 return -ENOMEM;
1593
1594         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1595         key.type = BTRFS_DEV_ITEM_KEY;
1596         key.offset = device->devid;
1597
1598         ret = btrfs_insert_empty_item(trans, root, path, &key,
1599                                       sizeof(*dev_item));
1600         if (ret)
1601                 goto out;
1602
1603         leaf = path->nodes[0];
1604         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1605
1606         btrfs_set_device_id(leaf, dev_item, device->devid);
1607         btrfs_set_device_generation(leaf, dev_item, 0);
1608         btrfs_set_device_type(leaf, dev_item, device->type);
1609         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1610         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1611         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1612         btrfs_set_device_total_bytes(leaf, dev_item,
1613                                      btrfs_device_get_disk_total_bytes(device));
1614         btrfs_set_device_bytes_used(leaf, dev_item,
1615                                     btrfs_device_get_bytes_used(device));
1616         btrfs_set_device_group(leaf, dev_item, 0);
1617         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1618         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1619         btrfs_set_device_start_offset(leaf, dev_item, 0);
1620
1621         ptr = btrfs_device_uuid(dev_item);
1622         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1623         ptr = btrfs_device_fsid(dev_item);
1624         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1625         btrfs_mark_buffer_dirty(leaf);
1626
1627         ret = 0;
1628 out:
1629         btrfs_free_path(path);
1630         return ret;
1631 }
1632
1633 /*
1634  * Function to update ctime/mtime for a given device path.
1635  * Mainly used for ctime/mtime based probe like libblkid.
1636  */
1637 static void update_dev_time(char *path_name)
1638 {
1639         struct file *filp;
1640
1641         filp = filp_open(path_name, O_RDWR, 0);
1642         if (IS_ERR(filp))
1643                 return;
1644         file_update_time(filp);
1645         filp_close(filp, NULL);
1646 }
1647
1648 static int btrfs_rm_dev_item(struct btrfs_root *root,
1649                              struct btrfs_device *device)
1650 {
1651         int ret;
1652         struct btrfs_path *path;
1653         struct btrfs_key key;
1654         struct btrfs_trans_handle *trans;
1655
1656         root = root->fs_info->chunk_root;
1657
1658         path = btrfs_alloc_path();
1659         if (!path)
1660                 return -ENOMEM;
1661
1662         trans = btrfs_start_transaction(root, 0);
1663         if (IS_ERR(trans)) {
1664                 btrfs_free_path(path);
1665                 return PTR_ERR(trans);
1666         }
1667         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1668         key.type = BTRFS_DEV_ITEM_KEY;
1669         key.offset = device->devid;
1670
1671         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1672         if (ret < 0)
1673                 goto out;
1674
1675         if (ret > 0) {
1676                 ret = -ENOENT;
1677                 goto out;
1678         }
1679
1680         ret = btrfs_del_item(trans, root, path);
1681         if (ret)
1682                 goto out;
1683 out:
1684         btrfs_free_path(path);
1685         btrfs_commit_transaction(trans, root);
1686         return ret;
1687 }
1688
1689 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1690 {
1691         struct btrfs_device *device;
1692         struct btrfs_device *next_device;
1693         struct block_device *bdev;
1694         struct buffer_head *bh = NULL;
1695         struct btrfs_super_block *disk_super;
1696         struct btrfs_fs_devices *cur_devices;
1697         u64 all_avail;
1698         u64 devid;
1699         u64 num_devices;
1700         u8 *dev_uuid;
1701         unsigned seq;
1702         int ret = 0;
1703         bool clear_super = false;
1704
1705         mutex_lock(&uuid_mutex);
1706
1707         do {
1708                 seq = read_seqbegin(&root->fs_info->profiles_lock);
1709
1710                 all_avail = root->fs_info->avail_data_alloc_bits |
1711                             root->fs_info->avail_system_alloc_bits |
1712                             root->fs_info->avail_metadata_alloc_bits;
1713         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
1714
1715         num_devices = root->fs_info->fs_devices->num_devices;
1716         btrfs_dev_replace_lock(&root->fs_info->dev_replace);
1717         if (btrfs_dev_replace_is_ongoing(&root->fs_info->dev_replace)) {
1718                 WARN_ON(num_devices < 1);
1719                 num_devices--;
1720         }
1721         btrfs_dev_replace_unlock(&root->fs_info->dev_replace);
1722
1723         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) && num_devices <= 4) {
1724                 ret = BTRFS_ERROR_DEV_RAID10_MIN_NOT_MET;
1725                 goto out;
1726         }
1727
1728         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) && num_devices <= 2) {
1729                 ret = BTRFS_ERROR_DEV_RAID1_MIN_NOT_MET;
1730                 goto out;
1731         }
1732
1733         if ((all_avail & BTRFS_BLOCK_GROUP_RAID5) &&
1734             root->fs_info->fs_devices->rw_devices <= 2) {
1735                 ret = BTRFS_ERROR_DEV_RAID5_MIN_NOT_MET;
1736                 goto out;
1737         }
1738         if ((all_avail & BTRFS_BLOCK_GROUP_RAID6) &&
1739             root->fs_info->fs_devices->rw_devices <= 3) {
1740                 ret = BTRFS_ERROR_DEV_RAID6_MIN_NOT_MET;
1741                 goto out;
1742         }
1743
1744         if (strcmp(device_path, "missing") == 0) {
1745                 struct list_head *devices;
1746                 struct btrfs_device *tmp;
1747
1748                 device = NULL;
1749                 devices = &root->fs_info->fs_devices->devices;
1750                 /*
1751                  * It is safe to read the devices since the volume_mutex
1752                  * is held.
1753                  */
1754                 list_for_each_entry(tmp, devices, dev_list) {
1755                         if (tmp->in_fs_metadata &&
1756                             !tmp->is_tgtdev_for_dev_replace &&
1757                             !tmp->bdev) {
1758                                 device = tmp;
1759                                 break;
1760                         }
1761                 }
1762                 bdev = NULL;
1763                 bh = NULL;
1764                 disk_super = NULL;
1765                 if (!device) {
1766                         ret = BTRFS_ERROR_DEV_MISSING_NOT_FOUND;
1767                         goto out;
1768                 }
1769         } else {
1770                 ret = btrfs_get_bdev_and_sb(device_path,
1771                                             FMODE_WRITE | FMODE_EXCL,
1772                                             root->fs_info->bdev_holder, 0,
1773                                             &bdev, &bh);
1774                 if (ret)
1775                         goto out;
1776                 disk_super = (struct btrfs_super_block *)bh->b_data;
1777                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1778                 dev_uuid = disk_super->dev_item.uuid;
1779                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1780                                            disk_super->fsid);
1781                 if (!device) {
1782                         ret = -ENOENT;
1783                         goto error_brelse;
1784                 }
1785         }
1786
1787         if (device->is_tgtdev_for_dev_replace) {
1788                 ret = BTRFS_ERROR_DEV_TGT_REPLACE;
1789                 goto error_brelse;
1790         }
1791
1792         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1793                 ret = BTRFS_ERROR_DEV_ONLY_WRITABLE;
1794                 goto error_brelse;
1795         }
1796
1797         if (device->writeable) {
1798                 lock_chunks(root);
1799                 list_del_init(&device->dev_alloc_list);
1800                 device->fs_devices->rw_devices--;
1801                 unlock_chunks(root);
1802                 clear_super = true;
1803         }
1804
1805         mutex_unlock(&uuid_mutex);
1806         ret = btrfs_shrink_device(device, 0);
1807         mutex_lock(&uuid_mutex);
1808         if (ret)
1809                 goto error_undo;
1810
1811         /*
1812          * TODO: the superblock still includes this device in its num_devices
1813          * counter although write_all_supers() is not locked out. This
1814          * could give a filesystem state which requires a degraded mount.
1815          */
1816         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1817         if (ret)
1818                 goto error_undo;
1819
1820         device->in_fs_metadata = 0;
1821         btrfs_scrub_cancel_dev(root->fs_info, device);
1822
1823         /*
1824          * the device list mutex makes sure that we don't change
1825          * the device list while someone else is writing out all
1826          * the device supers. Whoever is writing all supers, should
1827          * lock the device list mutex before getting the number of
1828          * devices in the super block (super_copy). Conversely,
1829          * whoever updates the number of devices in the super block
1830          * (super_copy) should hold the device list mutex.
1831          */
1832
1833         cur_devices = device->fs_devices;
1834         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1835         list_del_rcu(&device->dev_list);
1836
1837         device->fs_devices->num_devices--;
1838         device->fs_devices->total_devices--;
1839
1840         if (device->missing)
1841                 device->fs_devices->missing_devices--;
1842
1843         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1844                                  struct btrfs_device, dev_list);
1845         if (device->bdev == root->fs_info->sb->s_bdev)
1846                 root->fs_info->sb->s_bdev = next_device->bdev;
1847         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1848                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1849
1850         if (device->bdev) {
1851                 device->fs_devices->open_devices--;
1852                 /* remove sysfs entry */
1853                 btrfs_sysfs_rm_device_link(root->fs_info->fs_devices, device);
1854         }
1855
1856         call_rcu(&device->rcu, free_device);
1857
1858         num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
1859         btrfs_set_super_num_devices(root->fs_info->super_copy, num_devices);
1860         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1861
1862         if (cur_devices->open_devices == 0) {
1863                 struct btrfs_fs_devices *fs_devices;
1864                 fs_devices = root->fs_info->fs_devices;
1865                 while (fs_devices) {
1866                         if (fs_devices->seed == cur_devices) {
1867                                 fs_devices->seed = cur_devices->seed;
1868                                 break;
1869                         }
1870                         fs_devices = fs_devices->seed;
1871                 }
1872                 cur_devices->seed = NULL;
1873                 __btrfs_close_devices(cur_devices);
1874                 free_fs_devices(cur_devices);
1875         }
1876
1877         root->fs_info->num_tolerated_disk_barrier_failures =
1878                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1879
1880         /*
1881          * at this point, the device is zero sized.  We want to
1882          * remove it from the devices list and zero out the old super
1883          */
1884         if (clear_super && disk_super) {
1885                 u64 bytenr;
1886                 int i;
1887
1888                 /* make sure this device isn't detected as part of
1889                  * the FS anymore
1890                  */
1891                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1892                 set_buffer_dirty(bh);
1893                 sync_dirty_buffer(bh);
1894
1895                 /* clear the mirror copies of super block on the disk
1896                  * being removed, 0th copy is been taken care above and
1897                  * the below would take of the rest
1898                  */
1899                 for (i = 1; i < BTRFS_SUPER_MIRROR_MAX; i++) {
1900                         bytenr = btrfs_sb_offset(i);
1901                         if (bytenr + BTRFS_SUPER_INFO_SIZE >=
1902                                         i_size_read(bdev->bd_inode))
1903                                 break;
1904
1905                         brelse(bh);
1906                         bh = __bread(bdev, bytenr / 4096,
1907                                         BTRFS_SUPER_INFO_SIZE);
1908                         if (!bh)
1909                                 continue;
1910
1911                         disk_super = (struct btrfs_super_block *)bh->b_data;
1912
1913                         if (btrfs_super_bytenr(disk_super) != bytenr ||
1914                                 btrfs_super_magic(disk_super) != BTRFS_MAGIC) {
1915                                 continue;
1916                         }
1917                         memset(&disk_super->magic, 0,
1918                                                 sizeof(disk_super->magic));
1919                         set_buffer_dirty(bh);
1920                         sync_dirty_buffer(bh);
1921                 }
1922         }
1923
1924         ret = 0;
1925
1926         if (bdev) {
1927                 /* Notify udev that device has changed */
1928                 btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
1929
1930                 /* Update ctime/mtime for device path for libblkid */
1931                 update_dev_time(device_path);
1932         }
1933
1934 error_brelse:
1935         brelse(bh);
1936         if (bdev)
1937                 blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
1938 out:
1939         mutex_unlock(&uuid_mutex);
1940         return ret;
1941 error_undo:
1942         if (device->writeable) {
1943                 lock_chunks(root);
1944                 list_add(&device->dev_alloc_list,
1945                          &root->fs_info->fs_devices->alloc_list);
1946                 device->fs_devices->rw_devices++;
1947                 unlock_chunks(root);
1948         }
1949         goto error_brelse;
1950 }
1951
1952 void btrfs_rm_dev_replace_remove_srcdev(struct btrfs_fs_info *fs_info,
1953                                         struct btrfs_device *srcdev)
1954 {
1955         struct btrfs_fs_devices *fs_devices;
1956
1957         WARN_ON(!mutex_is_locked(&fs_info->fs_devices->device_list_mutex));
1958
1959         /*
1960          * in case of fs with no seed, srcdev->fs_devices will point
1961          * to fs_devices of fs_info. However when the dev being replaced is
1962          * a seed dev it will point to the seed's local fs_devices. In short
1963          * srcdev will have its correct fs_devices in both the cases.
1964          */
1965         fs_devices = srcdev->fs_devices;
1966
1967         list_del_rcu(&srcdev->dev_list);
1968         list_del_rcu(&srcdev->dev_alloc_list);
1969         fs_devices->num_devices--;
1970         if (srcdev->missing)
1971                 fs_devices->missing_devices--;
1972
1973         if (srcdev->writeable) {
1974                 fs_devices->rw_devices--;
1975                 /* zero out the old super if it is writable */
1976                 btrfs_scratch_superblocks(srcdev->bdev, srcdev->name->str);
1977         }
1978
1979         if (srcdev->bdev)
1980                 fs_devices->open_devices--;
1981 }
1982
1983 void btrfs_rm_dev_replace_free_srcdev(struct btrfs_fs_info *fs_info,
1984                                       struct btrfs_device *srcdev)
1985 {
1986         struct btrfs_fs_devices *fs_devices = srcdev->fs_devices;
1987
1988         call_rcu(&srcdev->rcu, free_device);
1989
1990         /*
1991          * unless fs_devices is seed fs, num_devices shouldn't go
1992          * zero
1993          */
1994         BUG_ON(!fs_devices->num_devices && !fs_devices->seeding);
1995
1996         /* if this is no devs we rather delete the fs_devices */
1997         if (!fs_devices->num_devices) {
1998                 struct btrfs_fs_devices *tmp_fs_devices;
1999
2000                 tmp_fs_devices = fs_info->fs_devices;
2001                 while (tmp_fs_devices) {
2002                         if (tmp_fs_devices->seed == fs_devices) {
2003                                 tmp_fs_devices->seed = fs_devices->seed;
2004                                 break;
2005                         }
2006                         tmp_fs_devices = tmp_fs_devices->seed;
2007                 }
2008                 fs_devices->seed = NULL;
2009                 __btrfs_close_devices(fs_devices);
2010                 free_fs_devices(fs_devices);
2011         }
2012 }
2013
2014 void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
2015                                       struct btrfs_device *tgtdev)
2016 {
2017         struct btrfs_device *next_device;
2018
2019         mutex_lock(&uuid_mutex);
2020         WARN_ON(!tgtdev);
2021         mutex_lock(&fs_info->fs_devices->device_list_mutex);
2022
2023         btrfs_sysfs_rm_device_link(fs_info->fs_devices, tgtdev);
2024
2025         if (tgtdev->bdev) {
2026                 btrfs_scratch_superblocks(tgtdev->bdev, tgtdev->name->str);
2027                 fs_info->fs_devices->open_devices--;
2028         }
2029         fs_info->fs_devices->num_devices--;
2030
2031         next_device = list_entry(fs_info->fs_devices->devices.next,
2032                                  struct btrfs_device, dev_list);
2033         if (tgtdev->bdev == fs_info->sb->s_bdev)
2034                 fs_info->sb->s_bdev = next_device->bdev;
2035         if (tgtdev->bdev == fs_info->fs_devices->latest_bdev)
2036                 fs_info->fs_devices->latest_bdev = next_device->bdev;
2037         list_del_rcu(&tgtdev->dev_list);
2038
2039         call_rcu(&tgtdev->rcu, free_device);
2040
2041         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2042         mutex_unlock(&uuid_mutex);
2043 }
2044
2045 static int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
2046                                      struct btrfs_device **device)
2047 {
2048         int ret = 0;
2049         struct btrfs_super_block *disk_super;
2050         u64 devid;
2051         u8 *dev_uuid;
2052         struct block_device *bdev;
2053         struct buffer_head *bh;
2054
2055         *device = NULL;
2056         ret = btrfs_get_bdev_and_sb(device_path, FMODE_READ,
2057                                     root->fs_info->bdev_holder, 0, &bdev, &bh);
2058         if (ret)
2059                 return ret;
2060         disk_super = (struct btrfs_super_block *)bh->b_data;
2061         devid = btrfs_stack_device_id(&disk_super->dev_item);
2062         dev_uuid = disk_super->dev_item.uuid;
2063         *device = btrfs_find_device(root->fs_info, devid, dev_uuid,
2064                                     disk_super->fsid);
2065         brelse(bh);
2066         if (!*device)
2067                 ret = -ENOENT;
2068         blkdev_put(bdev, FMODE_READ);
2069         return ret;
2070 }
2071
2072 int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
2073                                          char *device_path,
2074                                          struct btrfs_device **device)
2075 {
2076         *device = NULL;
2077         if (strcmp(device_path, "missing") == 0) {
2078                 struct list_head *devices;
2079                 struct btrfs_device *tmp;
2080
2081                 devices = &root->fs_info->fs_devices->devices;
2082                 /*
2083                  * It is safe to read the devices since the volume_mutex
2084                  * is held by the caller.
2085                  */
2086                 list_for_each_entry(tmp, devices, dev_list) {
2087                         if (tmp->in_fs_metadata && !tmp->bdev) {
2088                                 *device = tmp;
2089                                 break;
2090                         }
2091                 }
2092
2093                 if (!*device)
2094                         return BTRFS_ERROR_DEV_MISSING_NOT_FOUND;
2095
2096                 return 0;
2097         } else {
2098                 return btrfs_find_device_by_path(root, device_path, device);
2099         }
2100 }
2101
2102 /*
2103  * does all the dirty work required for changing file system's UUID.
2104  */
2105 static int btrfs_prepare_sprout(struct btrfs_root *root)
2106 {
2107         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
2108         struct btrfs_fs_devices *old_devices;
2109         struct btrfs_fs_devices *seed_devices;
2110         struct btrfs_super_block *disk_super = root->fs_info->super_copy;
2111         struct btrfs_device *device;
2112         u64 super_flags;
2113
2114         BUG_ON(!mutex_is_locked(&uuid_mutex));
2115         if (!fs_devices->seeding)
2116                 return -EINVAL;
2117
2118         seed_devices = __alloc_fs_devices();
2119         if (IS_ERR(seed_devices))
2120                 return PTR_ERR(seed_devices);
2121
2122         old_devices = clone_fs_devices(fs_devices);
2123         if (IS_ERR(old_devices)) {
2124                 kfree(seed_devices);
2125                 return PTR_ERR(old_devices);
2126         }
2127
2128         list_add(&old_devices->list, &fs_uuids);
2129
2130         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
2131         seed_devices->opened = 1;
2132         INIT_LIST_HEAD(&seed_devices->devices);
2133         INIT_LIST_HEAD(&seed_devices->alloc_list);
2134         mutex_init(&seed_devices->device_list_mutex);
2135
2136         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2137         list_splice_init_rcu(&fs_devices->devices, &seed_devices->devices,
2138                               synchronize_rcu);
2139         list_for_each_entry(device, &seed_devices->devices, dev_list)
2140                 device->fs_devices = seed_devices;
2141
2142         lock_chunks(root);
2143         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
2144         unlock_chunks(root);
2145
2146         fs_devices->seeding = 0;
2147         fs_devices->num_devices = 0;
2148         fs_devices->open_devices = 0;
2149         fs_devices->missing_devices = 0;
2150         fs_devices->rotating = 0;
2151         fs_devices->seed = seed_devices;
2152
2153         generate_random_uuid(fs_devices->fsid);
2154         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
2155         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
2156         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2157
2158         super_flags = btrfs_super_flags(disk_super) &
2159                       ~BTRFS_SUPER_FLAG_SEEDING;
2160         btrfs_set_super_flags(disk_super, super_flags);
2161
2162         return 0;
2163 }
2164
2165 /*
2166  * strore the expected generation for seed devices in device items.
2167  */
2168 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
2169                                struct btrfs_root *root)
2170 {
2171         struct btrfs_path *path;
2172         struct extent_buffer *leaf;
2173         struct btrfs_dev_item *dev_item;
2174         struct btrfs_device *device;
2175         struct btrfs_key key;
2176         u8 fs_uuid[BTRFS_UUID_SIZE];
2177         u8 dev_uuid[BTRFS_UUID_SIZE];
2178         u64 devid;
2179         int ret;
2180
2181         path = btrfs_alloc_path();
2182         if (!path)
2183                 return -ENOMEM;
2184
2185         root = root->fs_info->chunk_root;
2186         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2187         key.offset = 0;
2188         key.type = BTRFS_DEV_ITEM_KEY;
2189
2190         while (1) {
2191                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2192                 if (ret < 0)
2193                         goto error;
2194
2195                 leaf = path->nodes[0];
2196 next_slot:
2197                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
2198                         ret = btrfs_next_leaf(root, path);
2199                         if (ret > 0)
2200                                 break;
2201                         if (ret < 0)
2202                                 goto error;
2203                         leaf = path->nodes[0];
2204                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2205                         btrfs_release_path(path);
2206                         continue;
2207                 }
2208
2209                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2210                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
2211                     key.type != BTRFS_DEV_ITEM_KEY)
2212                         break;
2213
2214                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
2215                                           struct btrfs_dev_item);
2216                 devid = btrfs_device_id(leaf, dev_item);
2217                 read_extent_buffer(leaf, dev_uuid, btrfs_device_uuid(dev_item),
2218                                    BTRFS_UUID_SIZE);
2219                 read_extent_buffer(leaf, fs_uuid, btrfs_device_fsid(dev_item),
2220                                    BTRFS_UUID_SIZE);
2221                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
2222                                            fs_uuid);
2223                 BUG_ON(!device); /* Logic error */
2224
2225                 if (device->fs_devices->seeding) {
2226                         btrfs_set_device_generation(leaf, dev_item,
2227                                                     device->generation);
2228                         btrfs_mark_buffer_dirty(leaf);
2229                 }
2230
2231                 path->slots[0]++;
2232                 goto next_slot;
2233         }
2234         ret = 0;
2235 error:
2236         btrfs_free_path(path);
2237         return ret;
2238 }
2239
2240 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
2241 {
2242         struct request_queue *q;
2243         struct btrfs_trans_handle *trans;
2244         struct btrfs_device *device;
2245         struct block_device *bdev;
2246         struct list_head *devices;
2247         struct super_block *sb = root->fs_info->sb;
2248         struct rcu_string *name;
2249         u64 tmp;
2250         int seeding_dev = 0;
2251         int ret = 0;
2252
2253         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
2254                 return -EROFS;
2255
2256         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
2257                                   root->fs_info->bdev_holder);
2258         if (IS_ERR(bdev))
2259                 return PTR_ERR(bdev);
2260
2261         if (root->fs_info->fs_devices->seeding) {
2262                 seeding_dev = 1;
2263                 down_write(&sb->s_umount);
2264                 mutex_lock(&uuid_mutex);
2265         }
2266
2267         filemap_write_and_wait(bdev->bd_inode->i_mapping);
2268
2269         devices = &root->fs_info->fs_devices->devices;
2270
2271         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2272         list_for_each_entry(device, devices, dev_list) {
2273                 if (device->bdev == bdev) {
2274                         ret = -EEXIST;
2275                         mutex_unlock(
2276                                 &root->fs_info->fs_devices->device_list_mutex);
2277                         goto error;
2278                 }
2279         }
2280         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2281
2282         device = btrfs_alloc_device(root->fs_info, NULL, NULL);
2283         if (IS_ERR(device)) {
2284                 /* we can safely leave the fs_devices entry around */
2285                 ret = PTR_ERR(device);
2286                 goto error;
2287         }
2288
2289         name = rcu_string_strdup(device_path, GFP_NOFS);
2290         if (!name) {
2291                 kfree(device);
2292                 ret = -ENOMEM;
2293                 goto error;
2294         }
2295         rcu_assign_pointer(device->name, name);
2296
2297         trans = btrfs_start_transaction(root, 0);
2298         if (IS_ERR(trans)) {
2299                 rcu_string_free(device->name);
2300                 kfree(device);
2301                 ret = PTR_ERR(trans);
2302                 goto error;
2303         }
2304
2305         q = bdev_get_queue(bdev);
2306         if (blk_queue_discard(q))
2307                 device->can_discard = 1;
2308         device->writeable = 1;
2309         device->generation = trans->transid;
2310         device->io_width = root->sectorsize;
2311         device->io_align = root->sectorsize;
2312         device->sector_size = root->sectorsize;
2313         device->total_bytes = i_size_read(bdev->bd_inode);
2314         device->disk_total_bytes = device->total_bytes;
2315         device->commit_total_bytes = device->total_bytes;
2316         device->dev_root = root->fs_info->dev_root;
2317         device->bdev = bdev;
2318         device->in_fs_metadata = 1;
2319         device->is_tgtdev_for_dev_replace = 0;
2320         device->mode = FMODE_EXCL;
2321         device->dev_stats_valid = 1;
2322         set_blocksize(device->bdev, 4096);
2323
2324         if (seeding_dev) {
2325                 sb->s_flags &= ~MS_RDONLY;
2326                 ret = btrfs_prepare_sprout(root);
2327                 BUG_ON(ret); /* -ENOMEM */
2328         }
2329
2330         device->fs_devices = root->fs_info->fs_devices;
2331
2332         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2333         lock_chunks(root);
2334         list_add_rcu(&device->dev_list, &root->fs_info->fs_devices->devices);
2335         list_add(&device->dev_alloc_list,
2336                  &root->fs_info->fs_devices->alloc_list);
2337         root->fs_info->fs_devices->num_devices++;
2338         root->fs_info->fs_devices->open_devices++;
2339         root->fs_info->fs_devices->rw_devices++;
2340         root->fs_info->fs_devices->total_devices++;
2341         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
2342
2343         spin_lock(&root->fs_info->free_chunk_lock);
2344         root->fs_info->free_chunk_space += device->total_bytes;
2345         spin_unlock(&root->fs_info->free_chunk_lock);
2346
2347         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
2348                 root->fs_info->fs_devices->rotating = 1;
2349
2350         tmp = btrfs_super_total_bytes(root->fs_info->super_copy);
2351         btrfs_set_super_total_bytes(root->fs_info->super_copy,
2352                                     tmp + device->total_bytes);
2353
2354         tmp = btrfs_super_num_devices(root->fs_info->super_copy);
2355         btrfs_set_super_num_devices(root->fs_info->super_copy,
2356                                     tmp + 1);
2357
2358         /* add sysfs device entry */
2359         btrfs_sysfs_add_device_link(root->fs_info->fs_devices, device);
2360
2361         /*
2362          * we've got more storage, clear any full flags on the space
2363          * infos
2364          */
2365         btrfs_clear_space_info_full(root->fs_info);
2366
2367         unlock_chunks(root);
2368         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2369
2370         if (seeding_dev) {
2371                 lock_chunks(root);
2372                 ret = init_first_rw_device(trans, root, device);
2373                 unlock_chunks(root);
2374                 if (ret) {
2375                         btrfs_abort_transaction(trans, root, ret);
2376                         goto error_trans;
2377                 }
2378         }
2379
2380         ret = btrfs_add_device(trans, root, device);
2381         if (ret) {
2382                 btrfs_abort_transaction(trans, root, ret);
2383                 goto error_trans;
2384         }
2385
2386         if (seeding_dev) {
2387                 char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
2388
2389                 ret = btrfs_finish_sprout(trans, root);
2390                 if (ret) {
2391                         btrfs_abort_transaction(trans, root, ret);
2392                         goto error_trans;
2393                 }
2394
2395                 /* Sprouting would change fsid of the mounted root,
2396                  * so rename the fsid on the sysfs
2397                  */
2398                 snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU",
2399                                                 root->fs_info->fsid);
2400                 if (kobject_rename(&root->fs_info->fs_devices->fsid_kobj,
2401                                                                 fsid_buf))
2402                         btrfs_warn(root->fs_info,
2403                                 "sysfs: failed to create fsid for sprout");
2404         }
2405
2406         root->fs_info->num_tolerated_disk_barrier_failures =
2407                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
2408         ret = btrfs_commit_transaction(trans, root);
2409
2410         if (seeding_dev) {
2411                 mutex_unlock(&uuid_mutex);
2412                 up_write(&sb->s_umount);
2413
2414                 if (ret) /* transaction commit */
2415                         return ret;
2416
2417                 ret = btrfs_relocate_sys_chunks(root);
2418                 if (ret < 0)
2419                         btrfs_std_error(root->fs_info, ret,
2420                                     "Failed to relocate sys chunks after "
2421                                     "device initialization. This can be fixed "
2422                                     "using the \"btrfs balance\" command.");
2423                 trans = btrfs_attach_transaction(root);
2424                 if (IS_ERR(trans)) {
2425                         if (PTR_ERR(trans) == -ENOENT)
2426                                 return 0;
2427                         return PTR_ERR(trans);
2428                 }
2429                 ret = btrfs_commit_transaction(trans, root);
2430         }
2431
2432         /* Update ctime/mtime for libblkid */
2433         update_dev_time(device_path);
2434         return ret;
2435
2436 error_trans:
2437         btrfs_end_transaction(trans, root);
2438         rcu_string_free(device->name);
2439         btrfs_sysfs_rm_device_link(root->fs_info->fs_devices, device);
2440         kfree(device);
2441 error:
2442         blkdev_put(bdev, FMODE_EXCL);
2443         if (seeding_dev) {
2444                 mutex_unlock(&uuid_mutex);
2445                 up_write(&sb->s_umount);
2446         }
2447         return ret;
2448 }
2449
2450 int btrfs_init_dev_replace_tgtdev(struct btrfs_root *root, char *device_path,
2451                                   struct btrfs_device *srcdev,
2452                                   struct btrfs_device **device_out)
2453 {
2454         struct request_queue *q;
2455         struct btrfs_device *device;
2456         struct block_device *bdev;
2457         struct btrfs_fs_info *fs_info = root->fs_info;
2458         struct list_head *devices;
2459         struct rcu_string *name;
2460         u64 devid = BTRFS_DEV_REPLACE_DEVID;
2461         int ret = 0;
2462
2463         *device_out = NULL;
2464         if (fs_info->fs_devices->seeding) {
2465                 btrfs_err(fs_info, "the filesystem is a seed filesystem!");
2466                 return -EINVAL;
2467         }
2468
2469         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
2470                                   fs_info->bdev_holder);
2471         if (IS_ERR(bdev)) {
2472                 btrfs_err(fs_info, "target device %s is invalid!", device_path);
2473                 return PTR_ERR(bdev);
2474         }
2475
2476         filemap_write_and_wait(bdev->bd_inode->i_mapping);
2477
2478         devices = &fs_info->fs_devices->devices;
2479         list_for_each_entry(device, devices, dev_list) {
2480                 if (device->bdev == bdev) {
2481                         btrfs_err(fs_info, "target device is in the filesystem!");
2482                         ret = -EEXIST;
2483                         goto error;
2484                 }
2485         }
2486
2487
2488         if (i_size_read(bdev->bd_inode) <
2489             btrfs_device_get_total_bytes(srcdev)) {
2490                 btrfs_err(fs_info, "target device is smaller than source device!");
2491                 ret = -EINVAL;
2492                 goto error;
2493         }
2494
2495
2496         device = btrfs_alloc_device(NULL, &devid, NULL);
2497         if (IS_ERR(device)) {
2498                 ret = PTR_ERR(device);
2499                 goto error;
2500         }
2501
2502         name = rcu_string_strdup(device_path, GFP_NOFS);
2503         if (!name) {
2504                 kfree(device);
2505                 ret = -ENOMEM;
2506                 goto error;
2507         }
2508         rcu_assign_pointer(device->name, name);
2509
2510         q = bdev_get_queue(bdev);
2511         if (blk_queue_discard(q))
2512                 device->can_discard = 1;
2513         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2514         device->writeable = 1;
2515         device->generation = 0;
2516         device->io_width = root->sectorsize;
2517         device->io_align = root->sectorsize;
2518         device->sector_size = root->sectorsize;
2519         device->total_bytes = btrfs_device_get_total_bytes(srcdev);
2520         device->disk_total_bytes = btrfs_device_get_disk_total_bytes(srcdev);
2521         device->bytes_used = btrfs_device_get_bytes_used(srcdev);
2522         ASSERT(list_empty(&srcdev->resized_list));
2523         device->commit_total_bytes = srcdev->commit_total_bytes;
2524         device->commit_bytes_used = device->bytes_used;
2525         device->dev_root = fs_info->dev_root;
2526         device->bdev = bdev;
2527         device->in_fs_metadata = 1;
2528         device->is_tgtdev_for_dev_replace = 1;
2529         device->mode = FMODE_EXCL;
2530         device->dev_stats_valid = 1;
2531         set_blocksize(device->bdev, 4096);
2532         device->fs_devices = fs_info->fs_devices;
2533         list_add(&device->dev_list, &fs_info->fs_devices->devices);
2534         fs_info->fs_devices->num_devices++;
2535         fs_info->fs_devices->open_devices++;
2536         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2537
2538         *device_out = device;
2539         return ret;
2540
2541 error:
2542         blkdev_put(bdev, FMODE_EXCL);
2543         return ret;
2544 }
2545
2546 void btrfs_init_dev_replace_tgtdev_for_resume(struct btrfs_fs_info *fs_info,
2547                                               struct btrfs_device *tgtdev)
2548 {
2549         WARN_ON(fs_info->fs_devices->rw_devices == 0);
2550         tgtdev->io_width = fs_info->dev_root->sectorsize;
2551         tgtdev->io_align = fs_info->dev_root->sectorsize;
2552         tgtdev->sector_size = fs_info->dev_root->sectorsize;
2553         tgtdev->dev_root = fs_info->dev_root;
2554         tgtdev->in_fs_metadata = 1;
2555 }
2556
2557 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
2558                                         struct btrfs_device *device)
2559 {
2560         int ret;
2561         struct btrfs_path *path;
2562         struct btrfs_root *root;
2563         struct btrfs_dev_item *dev_item;
2564         struct extent_buffer *leaf;
2565         struct btrfs_key key;
2566
2567         root = device->dev_root->fs_info->chunk_root;
2568
2569         path = btrfs_alloc_path();
2570         if (!path)
2571                 return -ENOMEM;
2572
2573         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2574         key.type = BTRFS_DEV_ITEM_KEY;
2575         key.offset = device->devid;
2576
2577         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2578         if (ret < 0)
2579                 goto out;
2580
2581         if (ret > 0) {
2582                 ret = -ENOENT;
2583                 goto out;
2584         }
2585
2586         leaf = path->nodes[0];
2587         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
2588
2589         btrfs_set_device_id(leaf, dev_item, device->devid);
2590         btrfs_set_device_type(leaf, dev_item, device->type);
2591         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
2592         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
2593         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
2594         btrfs_set_device_total_bytes(leaf, dev_item,
2595                                      btrfs_device_get_disk_total_bytes(device));
2596         btrfs_set_device_bytes_used(leaf, dev_item,
2597                                     btrfs_device_get_bytes_used(device));
2598         btrfs_mark_buffer_dirty(leaf);
2599
2600 out:
2601         btrfs_free_path(path);
2602         return ret;
2603 }
2604
2605 int btrfs_grow_device(struct btrfs_trans_handle *trans,
2606                       struct btrfs_device *device, u64 new_size)
2607 {
2608         struct btrfs_super_block *super_copy =
2609                 device->dev_root->fs_info->super_copy;
2610         struct btrfs_fs_devices *fs_devices;
2611         u64 old_total;
2612         u64 diff;
2613
2614         if (!device->writeable)
2615                 return -EACCES;
2616
2617         lock_chunks(device->dev_root);
2618         old_total = btrfs_super_total_bytes(super_copy);
2619         diff = new_size - device->total_bytes;
2620
2621         if (new_size <= device->total_bytes ||
2622             device->is_tgtdev_for_dev_replace) {
2623                 unlock_chunks(device->dev_root);
2624                 return -EINVAL;
2625         }
2626
2627         fs_devices = device->dev_root->fs_info->fs_devices;
2628
2629         btrfs_set_super_total_bytes(super_copy, old_total + diff);
2630         device->fs_devices->total_rw_bytes += diff;
2631
2632         btrfs_device_set_total_bytes(device, new_size);
2633         btrfs_device_set_disk_total_bytes(device, new_size);
2634         btrfs_clear_space_info_full(device->dev_root->fs_info);
2635         if (list_empty(&device->resized_list))
2636                 list_add_tail(&device->resized_list,
2637                               &fs_devices->resized_devices);
2638         unlock_chunks(device->dev_root);
2639
2640         return btrfs_update_device(trans, device);
2641 }
2642
2643 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
2644                             struct btrfs_root *root, u64 chunk_objectid,
2645                             u64 chunk_offset)
2646 {
2647         int ret;
2648         struct btrfs_path *path;
2649         struct btrfs_key key;
2650
2651         root = root->fs_info->chunk_root;
2652         path = btrfs_alloc_path();
2653         if (!path)
2654                 return -ENOMEM;
2655
2656         key.objectid = chunk_objectid;
2657         key.offset = chunk_offset;
2658         key.type = BTRFS_CHUNK_ITEM_KEY;
2659
2660         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2661         if (ret < 0)
2662                 goto out;
2663         else if (ret > 0) { /* Logic error or corruption */
2664                 btrfs_std_error(root->fs_info, -ENOENT,
2665                             "Failed lookup while freeing chunk.");
2666                 ret = -ENOENT;
2667                 goto out;
2668         }
2669
2670         ret = btrfs_del_item(trans, root, path);
2671         if (ret < 0)
2672                 btrfs_std_error(root->fs_info, ret,
2673                             "Failed to delete chunk item.");
2674 out:
2675         btrfs_free_path(path);
2676         return ret;
2677 }
2678
2679 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
2680                         chunk_offset)
2681 {
2682         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
2683         struct btrfs_disk_key *disk_key;
2684         struct btrfs_chunk *chunk;
2685         u8 *ptr;
2686         int ret = 0;
2687         u32 num_stripes;
2688         u32 array_size;
2689         u32 len = 0;
2690         u32 cur;
2691         struct btrfs_key key;
2692
2693         lock_chunks(root);
2694         array_size = btrfs_super_sys_array_size(super_copy);
2695
2696         ptr = super_copy->sys_chunk_array;
2697         cur = 0;
2698
2699         while (cur < array_size) {
2700                 disk_key = (struct btrfs_disk_key *)ptr;
2701                 btrfs_disk_key_to_cpu(&key, disk_key);
2702
2703                 len = sizeof(*disk_key);
2704
2705                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
2706                         chunk = (struct btrfs_chunk *)(ptr + len);
2707                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
2708                         len += btrfs_chunk_item_size(num_stripes);
2709                 } else {
2710                         ret = -EIO;
2711                         break;
2712                 }
2713                 if (key.objectid == chunk_objectid &&
2714                     key.offset == chunk_offset) {
2715                         memmove(ptr, ptr + len, array_size - (cur + len));
2716                         array_size -= len;
2717                         btrfs_set_super_sys_array_size(super_copy, array_size);
2718                 } else {
2719                         ptr += len;
2720                         cur += len;
2721                 }
2722         }
2723         unlock_chunks(root);
2724         return ret;
2725 }
2726
2727 int btrfs_remove_chunk(struct btrfs_trans_handle *trans,
2728                        struct btrfs_root *root, u64 chunk_offset)
2729 {
2730         struct extent_map_tree *em_tree;
2731         struct extent_map *em;
2732         struct btrfs_root *extent_root = root->fs_info->extent_root;
2733         struct map_lookup *map;
2734         u64 dev_extent_len = 0;
2735         u64 chunk_objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2736         int i, ret = 0;
2737
2738         /* Just in case */
2739         root = root->fs_info->chunk_root;
2740         em_tree = &root->fs_info->mapping_tree.map_tree;
2741
2742         read_lock(&em_tree->lock);
2743         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
2744         read_unlock(&em_tree->lock);
2745
2746         if (!em || em->start > chunk_offset ||
2747             em->start + em->len < chunk_offset) {
2748                 /*
2749                  * This is a logic error, but we don't want to just rely on the
2750                  * user having built with ASSERT enabled, so if ASSERT doens't
2751                  * do anything we still error out.
2752                  */
2753                 ASSERT(0);
2754                 if (em)
2755                         free_extent_map(em);
2756                 return -EINVAL;
2757         }
2758         map = (struct map_lookup *)em->bdev;
2759         lock_chunks(root->fs_info->chunk_root);
2760         check_system_chunk(trans, extent_root, map->type);
2761         unlock_chunks(root->fs_info->chunk_root);
2762
2763         for (i = 0; i < map->num_stripes; i++) {
2764                 struct btrfs_device *device = map->stripes[i].dev;
2765                 ret = btrfs_free_dev_extent(trans, device,
2766                                             map->stripes[i].physical,
2767                                             &dev_extent_len);
2768                 if (ret) {
2769                         btrfs_abort_transaction(trans, root, ret);
2770                         goto out;
2771                 }
2772
2773                 if (device->bytes_used > 0) {
2774                         lock_chunks(root);
2775                         btrfs_device_set_bytes_used(device,
2776                                         device->bytes_used - dev_extent_len);
2777                         spin_lock(&root->fs_info->free_chunk_lock);
2778                         root->fs_info->free_chunk_space += dev_extent_len;
2779                         spin_unlock(&root->fs_info->free_chunk_lock);
2780                         btrfs_clear_space_info_full(root->fs_info);
2781                         unlock_chunks(root);
2782                 }
2783
2784                 if (map->stripes[i].dev) {
2785                         ret = btrfs_update_device(trans, map->stripes[i].dev);
2786                         if (ret) {
2787                                 btrfs_abort_transaction(trans, root, ret);
2788                                 goto out;
2789                         }
2790                 }
2791         }
2792         ret = btrfs_free_chunk(trans, root, chunk_objectid, chunk_offset);
2793         if (ret) {
2794                 btrfs_abort_transaction(trans, root, ret);
2795                 goto out;
2796         }
2797
2798         trace_btrfs_chunk_free(root, map, chunk_offset, em->len);
2799
2800         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2801                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
2802                 if (ret) {
2803                         btrfs_abort_transaction(trans, root, ret);
2804                         goto out;
2805                 }
2806         }
2807
2808         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset, em);
2809         if (ret) {
2810                 btrfs_abort_transaction(trans, extent_root, ret);
2811                 goto out;
2812         }
2813
2814 out:
2815         /* once for us */
2816         free_extent_map(em);
2817         return ret;
2818 }
2819
2820 static int btrfs_relocate_chunk(struct btrfs_root *root, u64 chunk_offset)
2821 {
2822         struct btrfs_root *extent_root;
2823         struct btrfs_trans_handle *trans;
2824         int ret;
2825
2826         root = root->fs_info->chunk_root;
2827         extent_root = root->fs_info->extent_root;
2828
2829         /*
2830          * Prevent races with automatic removal of unused block groups.
2831          * After we relocate and before we remove the chunk with offset
2832          * chunk_offset, automatic removal of the block group can kick in,
2833          * resulting in a failure when calling btrfs_remove_chunk() below.
2834          *
2835          * Make sure to acquire this mutex before doing a tree search (dev
2836          * or chunk trees) to find chunks. Otherwise the cleaner kthread might
2837          * call btrfs_remove_chunk() (through btrfs_delete_unused_bgs()) after
2838          * we release the path used to search the chunk/dev tree and before
2839          * the current task acquires this mutex and calls us.
2840          */
2841         ASSERT(mutex_is_locked(&root->fs_info->delete_unused_bgs_mutex));
2842
2843         ret = btrfs_can_relocate(extent_root, chunk_offset);
2844         if (ret)
2845                 return -ENOSPC;
2846
2847         /* step one, relocate all the extents inside this chunk */
2848         btrfs_scrub_pause(root);
2849         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
2850         btrfs_scrub_continue(root);
2851         if (ret)
2852                 return ret;
2853
2854         trans = btrfs_start_trans_remove_block_group(root->fs_info,
2855                                                      chunk_offset);
2856         if (IS_ERR(trans)) {
2857                 ret = PTR_ERR(trans);
2858                 btrfs_std_error(root->fs_info, ret, NULL);
2859                 return ret;
2860         }
2861
2862         /*
2863          * step two, delete the device extents and the
2864          * chunk tree entries
2865          */
2866         ret = btrfs_remove_chunk(trans, root, chunk_offset);
2867         btrfs_end_transaction(trans, root);
2868         return ret;
2869 }
2870
2871 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
2872 {
2873         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
2874         struct btrfs_path *path;
2875         struct extent_buffer *leaf;
2876         struct btrfs_chunk *chunk;
2877         struct btrfs_key key;
2878         struct btrfs_key found_key;
2879         u64 chunk_type;
2880         bool retried = false;
2881         int failed = 0;
2882         int ret;
2883
2884         path = btrfs_alloc_path();
2885         if (!path)
2886                 return -ENOMEM;
2887
2888 again:
2889         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2890         key.offset = (u64)-1;
2891         key.type = BTRFS_CHUNK_ITEM_KEY;
2892
2893         while (1) {
2894                 mutex_lock(&root->fs_info->delete_unused_bgs_mutex);
2895                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2896                 if (ret < 0) {
2897                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
2898                         goto error;
2899                 }
2900                 BUG_ON(ret == 0); /* Corruption */
2901
2902                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
2903                                           key.type);
2904                 if (ret)
2905                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
2906                 if (ret < 0)
2907                         goto error;
2908                 if (ret > 0)
2909                         break;
2910
2911                 leaf = path->nodes[0];
2912                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2913
2914                 chunk = btrfs_item_ptr(leaf, path->slots[0],
2915                                        struct btrfs_chunk);
2916                 chunk_type = btrfs_chunk_type(leaf, chunk);
2917                 btrfs_release_path(path);
2918
2919                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
2920                         ret = btrfs_relocate_chunk(chunk_root,
2921                                                    found_key.offset);
2922                         if (ret == -ENOSPC)
2923                                 failed++;
2924                         else
2925                                 BUG_ON(ret);
2926                 }
2927                 mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
2928
2929                 if (found_key.offset == 0)
2930                         break;
2931                 key.offset = found_key.offset - 1;
2932         }
2933         ret = 0;
2934         if (failed && !retried) {
2935                 failed = 0;
2936                 retried = true;
2937                 goto again;
2938         } else if (WARN_ON(failed && retried)) {
2939                 ret = -ENOSPC;
2940         }
2941 error:
2942         btrfs_free_path(path);
2943         return ret;
2944 }
2945
2946 static int insert_balance_item(struct btrfs_root *root,
2947                                struct btrfs_balance_control *bctl)
2948 {
2949         struct btrfs_trans_handle *trans;
2950         struct btrfs_balance_item *item;
2951         struct btrfs_disk_balance_args disk_bargs;
2952         struct btrfs_path *path;
2953         struct extent_buffer *leaf;
2954         struct btrfs_key key;
2955         int ret, err;
2956
2957         path = btrfs_alloc_path();
2958         if (!path)
2959                 return -ENOMEM;
2960
2961         trans = btrfs_start_transaction(root, 0);
2962         if (IS_ERR(trans)) {
2963                 btrfs_free_path(path);
2964                 return PTR_ERR(trans);
2965         }
2966
2967         key.objectid = BTRFS_BALANCE_OBJECTID;
2968         key.type = BTRFS_BALANCE_ITEM_KEY;
2969         key.offset = 0;
2970
2971         ret = btrfs_insert_empty_item(trans, root, path, &key,
2972                                       sizeof(*item));
2973         if (ret)
2974                 goto out;
2975
2976         leaf = path->nodes[0];
2977         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
2978
2979         memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
2980
2981         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->data);
2982         btrfs_set_balance_data(leaf, item, &disk_bargs);
2983         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->meta);
2984         btrfs_set_balance_meta(leaf, item, &disk_bargs);
2985         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->sys);
2986         btrfs_set_balance_sys(leaf, item, &disk_bargs);
2987
2988         btrfs_set_balance_flags(leaf, item, bctl->flags);
2989
2990         btrfs_mark_buffer_dirty(leaf);
2991 out:
2992         btrfs_free_path(path);
2993         err = btrfs_commit_transaction(trans, root);
2994         if (err && !ret)
2995                 ret = err;
2996         return ret;
2997 }
2998
2999 static int del_balance_item(struct btrfs_root *root)
3000 {
3001         struct btrfs_trans_handle *trans;
3002         struct btrfs_path *path;
3003         struct btrfs_key key;
3004         int ret, err;
3005
3006         path = btrfs_alloc_path();
3007         if (!path)
3008                 return -ENOMEM;
3009
3010         trans = btrfs_start_transaction(root, 0);
3011         if (IS_ERR(trans)) {
3012                 btrfs_free_path(path);
3013                 return PTR_ERR(trans);
3014         }
3015
3016         key.objectid = BTRFS_BALANCE_OBJECTID;
3017         key.type = BTRFS_BALANCE_ITEM_KEY;
3018         key.offset = 0;
3019
3020         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3021         if (ret < 0)
3022                 goto out;
3023         if (ret > 0) {
3024                 ret = -ENOENT;
3025                 goto out;
3026         }
3027
3028         ret = btrfs_del_item(trans, root, path);
3029 out:
3030         btrfs_free_path(path);
3031         err = btrfs_commit_transaction(trans, root);
3032         if (err && !ret)
3033                 ret = err;
3034         return ret;
3035 }
3036
3037 /*
3038  * This is a heuristic used to reduce the number of chunks balanced on
3039  * resume after balance was interrupted.
3040  */
3041 static void update_balance_args(struct btrfs_balance_control *bctl)
3042 {
3043         /*
3044          * Turn on soft mode for chunk types that were being converted.
3045          */
3046         if (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)
3047                 bctl->data.flags |= BTRFS_BALANCE_ARGS_SOFT;
3048         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)
3049                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_SOFT;
3050         if (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)
3051                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_SOFT;
3052
3053         /*
3054          * Turn on usage filter if is not already used.  The idea is
3055          * that chunks that we have already balanced should be
3056          * reasonably full.  Don't do it for chunks that are being
3057          * converted - that will keep us from relocating unconverted
3058          * (albeit full) chunks.
3059          */
3060         if (!(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE) &&
3061             !(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3062             !(bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
3063                 bctl->data.flags |= BTRFS_BALANCE_ARGS_USAGE;
3064                 bctl->data.usage = 90;
3065         }
3066         if (!(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE) &&
3067             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3068             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
3069                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_USAGE;
3070                 bctl->sys.usage = 90;
3071         }
3072         if (!(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE) &&
3073             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3074             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
3075                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_USAGE;
3076                 bctl->meta.usage = 90;
3077         }
3078 }
3079
3080 /*
3081  * Should be called with both balance and volume mutexes held to
3082  * serialize other volume operations (add_dev/rm_dev/resize) with
3083  * restriper.  Same goes for unset_balance_control.
3084  */
3085 static void set_balance_control(struct btrfs_balance_control *bctl)
3086 {
3087         struct btrfs_fs_info *fs_info = bctl->fs_info;
3088
3089         BUG_ON(fs_info->balance_ctl);
3090
3091         spin_lock(&fs_info->balance_lock);
3092         fs_info->balance_ctl = bctl;
3093         spin_unlock(&fs_info->balance_lock);
3094 }
3095
3096 static void unset_balance_control(struct btrfs_fs_info *fs_info)
3097 {
3098         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3099
3100         BUG_ON(!fs_info->balance_ctl);
3101
3102         spin_lock(&fs_info->balance_lock);
3103         fs_info->balance_ctl = NULL;
3104         spin_unlock(&fs_info->balance_lock);
3105
3106         kfree(bctl);
3107 }
3108
3109 /*
3110  * Balance filters.  Return 1 if chunk should be filtered out
3111  * (should not be balanced).
3112  */
3113 static int chunk_profiles_filter(u64 chunk_type,
3114                                  struct btrfs_balance_args *bargs)
3115 {
3116         chunk_type = chunk_to_extended(chunk_type) &
3117                                 BTRFS_EXTENDED_PROFILE_MASK;
3118
3119         if (bargs->profiles & chunk_type)
3120                 return 0;
3121
3122         return 1;
3123 }
3124
3125 static int chunk_usage_range_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
3126                               struct btrfs_balance_args *bargs)
3127 {
3128         struct btrfs_block_group_cache *cache;
3129         u64 chunk_used;
3130         u64 user_thresh_min;
3131         u64 user_thresh_max;
3132         int ret = 1;
3133
3134         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
3135         chunk_used = btrfs_block_group_used(&cache->item);
3136
3137         if (bargs->usage_min == 0)
3138                 user_thresh_min = 0;
3139         else
3140                 user_thresh_min = div_factor_fine(cache->key.offset,
3141                                         bargs->usage_min);
3142
3143         if (bargs->usage_max == 0)
3144                 user_thresh_max = 1;
3145         else if (bargs->usage_max > 100)
3146                 user_thresh_max = cache->key.offset;
3147         else
3148                 user_thresh_max = div_factor_fine(cache->key.offset,
3149                                         bargs->usage_max);
3150
3151         if (user_thresh_min <= chunk_used && chunk_used < user_thresh_max)
3152                 ret = 0;
3153
3154         btrfs_put_block_group(cache);
3155         return ret;
3156 }
3157
3158 static int chunk_usage_filter(struct btrfs_fs_info *fs_info,
3159                 u64 chunk_offset, struct btrfs_balance_args *bargs)
3160 {
3161         struct btrfs_block_group_cache *cache;
3162         u64 chunk_used, user_thresh;
3163         int ret = 1;
3164
3165         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
3166         chunk_used = btrfs_block_group_used(&cache->item);
3167
3168         if (bargs->usage_min == 0)
3169                 user_thresh = 1;
3170         else if (bargs->usage > 100)
3171                 user_thresh = cache->key.offset;
3172         else
3173                 user_thresh = div_factor_fine(cache->key.offset,
3174                                               bargs->usage);
3175
3176         if (chunk_used < user_thresh)
3177                 ret = 0;
3178
3179         btrfs_put_block_group(cache);
3180         return ret;
3181 }
3182
3183 static int chunk_devid_filter(struct extent_buffer *leaf,
3184                               struct btrfs_chunk *chunk,
3185                               struct btrfs_balance_args *bargs)
3186 {
3187         struct btrfs_stripe *stripe;
3188         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3189         int i;
3190
3191         for (i = 0; i < num_stripes; i++) {
3192                 stripe = btrfs_stripe_nr(chunk, i);
3193                 if (btrfs_stripe_devid(leaf, stripe) == bargs->devid)
3194                         return 0;
3195         }
3196
3197         return 1;
3198 }
3199
3200 /* [pstart, pend) */
3201 static int chunk_drange_filter(struct extent_buffer *leaf,
3202                                struct btrfs_chunk *chunk,
3203                                u64 chunk_offset,
3204                                struct btrfs_balance_args *bargs)
3205 {
3206         struct btrfs_stripe *stripe;
3207         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3208         u64 stripe_offset;
3209         u64 stripe_length;
3210         int factor;
3211         int i;
3212
3213         if (!(bargs->flags & BTRFS_BALANCE_ARGS_DEVID))
3214                 return 0;
3215
3216         if (btrfs_chunk_type(leaf, chunk) & (BTRFS_BLOCK_GROUP_DUP |
3217              BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)) {
3218                 factor = num_stripes / 2;
3219         } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID5) {
3220                 factor = num_stripes - 1;
3221         } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID6) {
3222                 factor = num_stripes - 2;
3223         } else {
3224                 factor = num_stripes;
3225         }
3226
3227         for (i = 0; i < num_stripes; i++) {
3228                 stripe = btrfs_stripe_nr(chunk, i);
3229                 if (btrfs_stripe_devid(leaf, stripe) != bargs->devid)
3230                         continue;
3231
3232                 stripe_offset = btrfs_stripe_offset(leaf, stripe);
3233                 stripe_length = btrfs_chunk_length(leaf, chunk);
3234                 stripe_length = div_u64(stripe_length, factor);
3235
3236                 if (stripe_offset < bargs->pend &&
3237                     stripe_offset + stripe_length > bargs->pstart)
3238                         return 0;
3239         }
3240
3241         return 1;
3242 }
3243
3244 /* [vstart, vend) */
3245 static int chunk_vrange_filter(struct extent_buffer *leaf,
3246                                struct btrfs_chunk *chunk,
3247                                u64 chunk_offset,
3248                                struct btrfs_balance_args *bargs)
3249 {
3250         if (chunk_offset < bargs->vend &&
3251             chunk_offset + btrfs_chunk_length(leaf, chunk) > bargs->vstart)
3252                 /* at least part of the chunk is inside this vrange */
3253                 return 0;
3254
3255         return 1;
3256 }
3257
3258 static int chunk_stripes_range_filter(struct extent_buffer *leaf,
3259                                struct btrfs_chunk *chunk,
3260                                struct btrfs_balance_args *bargs)
3261 {
3262         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3263
3264         if (bargs->stripes_min <= num_stripes
3265                         && num_stripes <= bargs->stripes_max)
3266                 return 0;
3267
3268         return 1;
3269 }
3270
3271 static int chunk_soft_convert_filter(u64 chunk_type,
3272                                      struct btrfs_balance_args *bargs)
3273 {
3274         if (!(bargs->flags & BTRFS_BALANCE_ARGS_CONVERT))
3275                 return 0;
3276
3277         chunk_type = chunk_to_extended(chunk_type) &
3278                                 BTRFS_EXTENDED_PROFILE_MASK;
3279
3280         if (bargs->target == chunk_type)
3281                 return 1;
3282
3283         return 0;
3284 }
3285
3286 static int should_balance_chunk(struct btrfs_root *root,
3287                                 struct extent_buffer *leaf,
3288                                 struct btrfs_chunk *chunk, u64 chunk_offset)
3289 {
3290         struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
3291         struct btrfs_balance_args *bargs = NULL;
3292         u64 chunk_type = btrfs_chunk_type(leaf, chunk);
3293
3294         /* type filter */
3295         if (!((chunk_type & BTRFS_BLOCK_GROUP_TYPE_MASK) &
3296               (bctl->flags & BTRFS_BALANCE_TYPE_MASK))) {
3297                 return 0;
3298         }
3299
3300         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
3301                 bargs = &bctl->data;
3302         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
3303                 bargs = &bctl->sys;
3304         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
3305                 bargs = &bctl->meta;
3306
3307         /* profiles filter */
3308         if ((bargs->flags & BTRFS_BALANCE_ARGS_PROFILES) &&
3309             chunk_profiles_filter(chunk_type, bargs)) {
3310                 return 0;
3311         }
3312
3313         /* usage filter */
3314         if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
3315             chunk_usage_filter(bctl->fs_info, chunk_offset, bargs)) {
3316                 return 0;
3317         } else if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3318             chunk_usage_range_filter(bctl->fs_info, chunk_offset, bargs)) {
3319                 return 0;
3320         }
3321
3322         /* devid filter */
3323         if ((bargs->flags & BTRFS_BALANCE_ARGS_DEVID) &&
3324             chunk_devid_filter(leaf, chunk, bargs)) {
3325                 return 0;
3326         }
3327
3328         /* drange filter, makes sense only with devid filter */
3329         if ((bargs->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
3330             chunk_drange_filter(leaf, chunk, chunk_offset, bargs)) {
3331                 return 0;
3332         }
3333
3334         /* vrange filter */
3335         if ((bargs->flags & BTRFS_BALANCE_ARGS_VRANGE) &&
3336             chunk_vrange_filter(leaf, chunk, chunk_offset, bargs)) {
3337                 return 0;
3338         }
3339
3340         /* stripes filter */
3341         if ((bargs->flags & BTRFS_BALANCE_ARGS_STRIPES_RANGE) &&
3342             chunk_stripes_range_filter(leaf, chunk, bargs)) {
3343                 return 0;
3344         }
3345
3346         /* soft profile changing mode */
3347         if ((bargs->flags & BTRFS_BALANCE_ARGS_SOFT) &&
3348             chunk_soft_convert_filter(chunk_type, bargs)) {
3349                 return 0;
3350         }
3351
3352         /*
3353          * limited by count, must be the last filter
3354          */
3355         if ((bargs->flags & BTRFS_BALANCE_ARGS_LIMIT)) {
3356                 if (bargs->limit == 0)
3357                         return 0;
3358                 else
3359                         bargs->limit--;
3360         } else if ((bargs->flags & BTRFS_BALANCE_ARGS_LIMIT_RANGE)) {
3361                 /*
3362                  * Same logic as the 'limit' filter; the minimum cannot be
3363                  * determined here because we do not have the global informatoin
3364                  * about the count of all chunks that satisfy the filters.
3365                  */
3366                 if (bargs->limit_max == 0)
3367                         return 0;
3368                 else
3369                         bargs->limit_max--;
3370         }
3371
3372         return 1;
3373 }
3374
3375 static int __btrfs_balance(struct btrfs_fs_info *fs_info)
3376 {
3377         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3378         struct btrfs_root *chunk_root = fs_info->chunk_root;
3379         struct btrfs_root *dev_root = fs_info->dev_root;
3380         struct list_head *devices;
3381         struct btrfs_device *device;
3382         u64 old_size;
3383         u64 size_to_free;
3384         u64 chunk_type;
3385         struct btrfs_chunk *chunk;
3386         struct btrfs_path *path;
3387         struct btrfs_key key;
3388         struct btrfs_key found_key;
3389         struct btrfs_trans_handle *trans;
3390         struct extent_buffer *leaf;
3391         int slot;
3392         int ret;
3393         int enospc_errors = 0;
3394         bool counting = true;
3395         /* The single value limit and min/max limits use the same bytes in the */
3396         u64 limit_data = bctl->data.limit;
3397         u64 limit_meta = bctl->meta.limit;
3398         u64 limit_sys = bctl->sys.limit;
3399         u32 count_data = 0;
3400         u32 count_meta = 0;
3401         u32 count_sys = 0;
3402         int chunk_reserved = 0;
3403
3404         /* step one make some room on all the devices */
3405         devices = &fs_info->fs_devices->devices;
3406         list_for_each_entry(device, devices, dev_list) {
3407                 old_size = btrfs_device_get_total_bytes(device);
3408                 size_to_free = div_factor(old_size, 1);
3409                 size_to_free = min_t(u64, size_to_free, SZ_1M);
3410                 if (!device->writeable ||
3411                     btrfs_device_get_total_bytes(device) -
3412                     btrfs_device_get_bytes_used(device) > size_to_free ||
3413                     device->is_tgtdev_for_dev_replace)
3414                         continue;
3415
3416                 ret = btrfs_shrink_device(device, old_size - size_to_free);
3417                 if (ret == -ENOSPC)
3418                         break;
3419                 BUG_ON(ret);
3420
3421                 trans = btrfs_start_transaction(dev_root, 0);
3422                 BUG_ON(IS_ERR(trans));
3423
3424                 ret = btrfs_grow_device(trans, device, old_size);
3425                 BUG_ON(ret);
3426
3427                 btrfs_end_transaction(trans, dev_root);
3428         }
3429
3430         /* step two, relocate all the chunks */
3431         path = btrfs_alloc_path();
3432         if (!path) {
3433                 ret = -ENOMEM;
3434                 goto error;
3435         }
3436
3437         /* zero out stat counters */
3438         spin_lock(&fs_info->balance_lock);
3439         memset(&bctl->stat, 0, sizeof(bctl->stat));
3440         spin_unlock(&fs_info->balance_lock);
3441 again:
3442         if (!counting) {
3443                 /*
3444                  * The single value limit and min/max limits use the same bytes
3445                  * in the
3446                  */
3447                 bctl->data.limit = limit_data;
3448                 bctl->meta.limit = limit_meta;
3449                 bctl->sys.limit = limit_sys;
3450         }
3451         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
3452         key.offset = (u64)-1;
3453         key.type = BTRFS_CHUNK_ITEM_KEY;
3454
3455         while (1) {
3456                 if ((!counting && atomic_read(&fs_info->balance_pause_req)) ||
3457                     atomic_read(&fs_info->balance_cancel_req)) {
3458                         ret = -ECANCELED;
3459                         goto error;
3460                 }
3461
3462                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
3463                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
3464                 if (ret < 0) {
3465                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3466                         goto error;
3467                 }
3468
3469                 /*
3470                  * this shouldn't happen, it means the last relocate
3471                  * failed
3472                  */
3473                 if (ret == 0)
3474                         BUG(); /* FIXME break ? */
3475
3476                 ret = btrfs_previous_item(chunk_root, path, 0,
3477                                           BTRFS_CHUNK_ITEM_KEY);
3478                 if (ret) {
3479                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3480                         ret = 0;
3481                         break;
3482                 }
3483
3484                 leaf = path->nodes[0];
3485                 slot = path->slots[0];
3486                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3487
3488                 if (found_key.objectid != key.objectid) {
3489                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3490                         break;
3491                 }
3492
3493                 chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
3494                 chunk_type = btrfs_chunk_type(leaf, chunk);
3495
3496                 if (!counting) {
3497                         spin_lock(&fs_info->balance_lock);
3498                         bctl->stat.considered++;
3499                         spin_unlock(&fs_info->balance_lock);
3500                 }
3501
3502                 ret = should_balance_chunk(chunk_root, leaf, chunk,
3503                                            found_key.offset);
3504
3505                 btrfs_release_path(path);
3506                 if (!ret) {
3507                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3508                         goto loop;
3509                 }
3510
3511                 if (counting) {
3512                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3513                         spin_lock(&fs_info->balance_lock);
3514                         bctl->stat.expected++;
3515                         spin_unlock(&fs_info->balance_lock);
3516
3517                         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
3518                                 count_data++;
3519                         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
3520                                 count_sys++;
3521                         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
3522                                 count_meta++;
3523
3524                         goto loop;
3525                 }
3526
3527                 /*
3528                  * Apply limit_min filter, no need to check if the LIMITS
3529                  * filter is used, limit_min is 0 by default
3530                  */
3531                 if (((chunk_type & BTRFS_BLOCK_GROUP_DATA) &&
3532                                         count_data < bctl->data.limit_min)
3533                                 || ((chunk_type & BTRFS_BLOCK_GROUP_METADATA) &&
3534                                         count_meta < bctl->meta.limit_min)
3535                                 || ((chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) &&
3536                                         count_sys < bctl->sys.limit_min)) {
3537                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3538                         goto loop;
3539                 }
3540
3541                 if ((chunk_type & BTRFS_BLOCK_GROUP_DATA) && !chunk_reserved) {
3542                         trans = btrfs_start_transaction(chunk_root, 0);
3543                         if (IS_ERR(trans)) {
3544                                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3545                                 ret = PTR_ERR(trans);
3546                                 goto error;
3547                         }
3548
3549                         ret = btrfs_force_chunk_alloc(trans, chunk_root,
3550                                                       BTRFS_BLOCK_GROUP_DATA);
3551                         btrfs_end_transaction(trans, chunk_root);
3552                         if (ret < 0) {
3553                                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3554                                 goto error;
3555                         }
3556                         chunk_reserved = 1;
3557                 }
3558
3559                 ret = btrfs_relocate_chunk(chunk_root,
3560                                            found_key.offset);
3561                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3562                 if (ret && ret != -ENOSPC)
3563                         goto error;
3564                 if (ret == -ENOSPC) {
3565                         enospc_errors++;
3566                 } else {
3567                         spin_lock(&fs_info->balance_lock);
3568                         bctl->stat.completed++;
3569                         spin_unlock(&fs_info->balance_lock);
3570                 }
3571 loop:
3572                 if (found_key.offset == 0)
3573                         break;
3574                 key.offset = found_key.offset - 1;
3575         }
3576
3577         if (counting) {
3578                 btrfs_release_path(path);
3579                 counting = false;
3580                 goto again;
3581         }
3582 error:
3583         btrfs_free_path(path);
3584         if (enospc_errors) {
3585                 btrfs_info(fs_info, "%d enospc errors during balance",
3586                        enospc_errors);
3587                 if (!ret)
3588                         ret = -ENOSPC;
3589         }
3590
3591         return ret;
3592 }
3593
3594 /**
3595  * alloc_profile_is_valid - see if a given profile is valid and reduced
3596  * @flags: profile to validate
3597  * @extended: if true @flags is treated as an extended profile
3598  */
3599 static int alloc_profile_is_valid(u64 flags, int extended)
3600 {
3601         u64 mask = (extended ? BTRFS_EXTENDED_PROFILE_MASK :
3602                                BTRFS_BLOCK_GROUP_PROFILE_MASK);
3603
3604         flags &= ~BTRFS_BLOCK_GROUP_TYPE_MASK;
3605
3606         /* 1) check that all other bits are zeroed */
3607         if (flags & ~mask)
3608                 return 0;
3609
3610         /* 2) see if profile is reduced */
3611         if (flags == 0)
3612                 return !extended; /* "0" is valid for usual profiles */
3613
3614         /* true if exactly one bit set */
3615         return (flags & (flags - 1)) == 0;
3616 }
3617
3618 static inline int balance_need_close(struct btrfs_fs_info *fs_info)
3619 {
3620         /* cancel requested || normal exit path */
3621         return atomic_read(&fs_info->balance_cancel_req) ||
3622                 (atomic_read(&fs_info->balance_pause_req) == 0 &&
3623                  atomic_read(&fs_info->balance_cancel_req) == 0);
3624 }
3625
3626 static void __cancel_balance(struct btrfs_fs_info *fs_info)
3627 {
3628         int ret;
3629
3630         unset_balance_control(fs_info);
3631         ret = del_balance_item(fs_info->tree_root);
3632         if (ret)
3633                 btrfs_std_error(fs_info, ret, NULL);
3634
3635         atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3636 }
3637
3638 /* Non-zero return value signifies invalidity */
3639 static inline int validate_convert_profile(struct btrfs_balance_args *bctl_arg,
3640                 u64 allowed)
3641 {
3642         return ((bctl_arg->flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3643                 (!alloc_profile_is_valid(bctl_arg->target, 1) ||
3644                  (bctl_arg->target & ~allowed)));
3645 }
3646
3647 /*
3648  * Should be called with both balance and volume mutexes held
3649  */
3650 int btrfs_balance(struct btrfs_balance_control *bctl,
3651                   struct btrfs_ioctl_balance_args *bargs)
3652 {
3653         struct btrfs_fs_info *fs_info = bctl->fs_info;
3654         u64 allowed;
3655         int mixed = 0;
3656         int ret;
3657         u64 num_devices;
3658         unsigned seq;
3659
3660         if (btrfs_fs_closing(fs_info) ||
3661             atomic_read(&fs_info->balance_pause_req) ||
3662             atomic_read(&fs_info->balance_cancel_req)) {
3663                 ret = -EINVAL;
3664                 goto out;
3665         }
3666
3667         allowed = btrfs_super_incompat_flags(fs_info->super_copy);
3668         if (allowed & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
3669                 mixed = 1;
3670
3671         /*
3672          * In case of mixed groups both data and meta should be picked,
3673          * and identical options should be given for both of them.
3674          */
3675         allowed = BTRFS_BALANCE_DATA | BTRFS_BALANCE_METADATA;
3676         if (mixed && (bctl->flags & allowed)) {
3677                 if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
3678                     !(bctl->flags & BTRFS_BALANCE_METADATA) ||
3679                     memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
3680                         btrfs_err(fs_info, "with mixed groups data and "
3681                                    "metadata balance options must be the same");
3682                         ret = -EINVAL;
3683                         goto out;
3684                 }
3685         }
3686
3687         num_devices = fs_info->fs_devices->num_devices;
3688         btrfs_dev_replace_lock(&fs_info->dev_replace);
3689         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) {
3690                 BUG_ON(num_devices < 1);
3691                 num_devices--;
3692         }
3693         btrfs_dev_replace_unlock(&fs_info->dev_replace);
3694         allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
3695         if (num_devices == 1)
3696                 allowed |= BTRFS_BLOCK_GROUP_DUP;
3697         else if (num_devices > 1)
3698                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1);
3699         if (num_devices > 2)
3700                 allowed |= BTRFS_BLOCK_GROUP_RAID5;
3701         if (num_devices > 3)
3702                 allowed |= (BTRFS_BLOCK_GROUP_RAID10 |
3703                             BTRFS_BLOCK_GROUP_RAID6);
3704         if (validate_convert_profile(&bctl->data, allowed)) {
3705                 btrfs_err(fs_info, "unable to start balance with target "
3706                            "data profile %llu",
3707                        bctl->data.target);
3708                 ret = -EINVAL;
3709                 goto out;
3710         }
3711         if (validate_convert_profile(&bctl->meta, allowed)) {
3712                 btrfs_err(fs_info,
3713                            "unable to start balance with target metadata profile %llu",
3714                        bctl->meta.target);
3715                 ret = -EINVAL;
3716                 goto out;
3717         }
3718         if (validate_convert_profile(&bctl->sys, allowed)) {
3719                 btrfs_err(fs_info,
3720                            "unable to start balance with target system profile %llu",
3721                        bctl->sys.target);
3722                 ret = -EINVAL;
3723                 goto out;
3724         }
3725
3726         /* allow to reduce meta or sys integrity only if force set */
3727         allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3728                         BTRFS_BLOCK_GROUP_RAID10 |
3729                         BTRFS_BLOCK_GROUP_RAID5 |
3730                         BTRFS_BLOCK_GROUP_RAID6;
3731         do {
3732                 seq = read_seqbegin(&fs_info->profiles_lock);
3733
3734                 if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3735                      (fs_info->avail_system_alloc_bits & allowed) &&
3736                      !(bctl->sys.target & allowed)) ||
3737                     ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3738                      (fs_info->avail_metadata_alloc_bits & allowed) &&
3739                      !(bctl->meta.target & allowed))) {
3740                         if (bctl->flags & BTRFS_BALANCE_FORCE) {
3741                                 btrfs_info(fs_info, "force reducing metadata integrity");
3742                         } else {
3743                                 btrfs_err(fs_info, "balance will reduce metadata "
3744                                            "integrity, use force if you want this");
3745                                 ret = -EINVAL;
3746                                 goto out;
3747                         }
3748                 }
3749         } while (read_seqretry(&fs_info->profiles_lock, seq));
3750
3751         if (btrfs_get_num_tolerated_disk_barrier_failures(bctl->meta.target) <
3752                 btrfs_get_num_tolerated_disk_barrier_failures(bctl->data.target)) {
3753                 btrfs_warn(fs_info,
3754         "metatdata profile 0x%llx has lower redundancy than data profile 0x%llx",
3755                         bctl->meta.target, bctl->data.target);
3756         }
3757
3758         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3759                 fs_info->num_tolerated_disk_barrier_failures = min(
3760                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info),
3761                         btrfs_get_num_tolerated_disk_barrier_failures(
3762                                 bctl->sys.target));
3763         }
3764
3765         ret = insert_balance_item(fs_info->tree_root, bctl);
3766         if (ret && ret != -EEXIST)
3767                 goto out;
3768
3769         if (!(bctl->flags & BTRFS_BALANCE_RESUME)) {
3770                 BUG_ON(ret == -EEXIST);
3771                 set_balance_control(bctl);
3772         } else {
3773                 BUG_ON(ret != -EEXIST);
3774                 spin_lock(&fs_info->balance_lock);
3775                 update_balance_args(bctl);
3776                 spin_unlock(&fs_info->balance_lock);
3777         }
3778
3779         atomic_inc(&fs_info->balance_running);
3780         mutex_unlock(&fs_info->balance_mutex);
3781
3782         ret = __btrfs_balance(fs_info);
3783
3784         mutex_lock(&fs_info->balance_mutex);
3785         atomic_dec(&fs_info->balance_running);
3786
3787         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3788                 fs_info->num_tolerated_disk_barrier_failures =
3789                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
3790         }
3791
3792         if (bargs) {
3793                 memset(bargs, 0, sizeof(*bargs));
3794                 update_ioctl_balance_args(fs_info, 0, bargs);
3795         }
3796
3797         if ((ret && ret != -ECANCELED && ret != -ENOSPC) ||
3798             balance_need_close(fs_info)) {
3799                 __cancel_balance(fs_info);
3800         }
3801
3802         wake_up(&fs_info->balance_wait_q);
3803
3804         return ret;
3805 out:
3806         if (bctl->flags & BTRFS_BALANCE_RESUME)
3807                 __cancel_balance(fs_info);
3808         else {
3809                 kfree(bctl);
3810                 atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3811         }
3812         return ret;
3813 }
3814
3815 static int balance_kthread(void *data)
3816 {
3817         struct btrfs_fs_info *fs_info = data;
3818         int ret = 0;
3819
3820         mutex_lock(&fs_info->volume_mutex);
3821         mutex_lock(&fs_info->balance_mutex);
3822
3823         if (fs_info->balance_ctl) {
3824                 btrfs_info(fs_info, "continuing balance");
3825                 ret = btrfs_balance(fs_info->balance_ctl, NULL);
3826         }
3827
3828         mutex_unlock(&fs_info->balance_mutex);
3829         mutex_unlock(&fs_info->volume_mutex);
3830
3831         return ret;
3832 }
3833
3834 int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
3835 {
3836         struct task_struct *tsk;
3837
3838         spin_lock(&fs_info->balance_lock);
3839         if (!fs_info->balance_ctl) {
3840                 spin_unlock(&fs_info->balance_lock);
3841                 return 0;
3842         }
3843         spin_unlock(&fs_info->balance_lock);
3844
3845         if (btrfs_test_opt(fs_info->tree_root, SKIP_BALANCE)) {
3846                 btrfs_info(fs_info, "force skipping balance");
3847                 return 0;
3848         }
3849
3850         tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance");
3851         return PTR_ERR_OR_ZERO(tsk);
3852 }
3853
3854 int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
3855 {
3856         struct btrfs_balance_control *bctl;
3857         struct btrfs_balance_item *item;
3858         struct btrfs_disk_balance_args disk_bargs;
3859         struct btrfs_path *path;
3860         struct extent_buffer *leaf;
3861         struct btrfs_key key;
3862         int ret;
3863
3864         path = btrfs_alloc_path();
3865         if (!path)
3866                 return -ENOMEM;
3867
3868         key.objectid = BTRFS_BALANCE_OBJECTID;
3869         key.type = BTRFS_BALANCE_ITEM_KEY;
3870         key.offset = 0;
3871
3872         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
3873         if (ret < 0)
3874                 goto out;
3875         if (ret > 0) { /* ret = -ENOENT; */
3876                 ret = 0;
3877                 goto out;
3878         }
3879
3880         bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
3881         if (!bctl) {
3882                 ret = -ENOMEM;
3883                 goto out;
3884         }
3885
3886         leaf = path->nodes[0];
3887         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
3888
3889         bctl->fs_info = fs_info;
3890         bctl->flags = btrfs_balance_flags(leaf, item);
3891         bctl->flags |= BTRFS_BALANCE_RESUME;
3892
3893         btrfs_balance_data(leaf, item, &disk_bargs);
3894         btrfs_disk_balance_args_to_cpu(&bctl->data, &disk_bargs);
3895         btrfs_balance_meta(leaf, item, &disk_bargs);
3896         btrfs_disk_balance_args_to_cpu(&bctl->meta, &disk_bargs);
3897         btrfs_balance_sys(leaf, item, &disk_bargs);
3898         btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
3899
3900         WARN_ON(atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1));
3901
3902         mutex_lock(&fs_info->volume_mutex);
3903         mutex_lock(&fs_info->balance_mutex);
3904
3905         set_balance_control(bctl);
3906
3907         mutex_unlock(&fs_info->balance_mutex);
3908         mutex_unlock(&fs_info->volume_mutex);
3909 out:
3910         btrfs_free_path(path);
3911         return ret;
3912 }
3913
3914 int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
3915 {
3916         int ret = 0;
3917
3918         mutex_lock(&fs_info->balance_mutex);
3919         if (!fs_info->balance_ctl) {
3920                 mutex_unlock(&fs_info->balance_mutex);
3921                 return -ENOTCONN;
3922         }
3923
3924         if (atomic_read(&fs_info->balance_running)) {
3925                 atomic_inc(&fs_info->balance_pause_req);
3926                 mutex_unlock(&fs_info->balance_mutex);
3927
3928                 wait_event(fs_info->balance_wait_q,
3929                            atomic_read(&fs_info->balance_running) == 0);
3930
3931                 mutex_lock(&fs_info->balance_mutex);
3932                 /* we are good with balance_ctl ripped off from under us */
3933                 BUG_ON(atomic_read(&fs_info->balance_running));
3934                 atomic_dec(&fs_info->balance_pause_req);
3935         } else {
3936                 ret = -ENOTCONN;
3937         }
3938
3939         mutex_unlock(&fs_info->balance_mutex);
3940         return ret;
3941 }
3942
3943 int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
3944 {
3945         if (fs_info->sb->s_flags & MS_RDONLY)
3946                 return -EROFS;
3947
3948         mutex_lock(&fs_info->balance_mutex);
3949         if (!fs_info->balance_ctl) {
3950                 mutex_unlock(&fs_info->balance_mutex);
3951                 return -ENOTCONN;
3952         }
3953
3954         atomic_inc(&fs_info->balance_cancel_req);
3955         /*
3956          * if we are running just wait and return, balance item is
3957          * deleted in btrfs_balance in this case
3958          */
3959         if (atomic_read(&fs_info->balance_running)) {
3960                 mutex_unlock(&fs_info->balance_mutex);
3961                 wait_event(fs_info->balance_wait_q,
3962                            atomic_read(&fs_info->balance_running) == 0);
3963                 mutex_lock(&fs_info->balance_mutex);
3964         } else {
3965                 /* __cancel_balance needs volume_mutex */
3966                 mutex_unlock(&fs_info->balance_mutex);
3967                 mutex_lock(&fs_info->volume_mutex);
3968                 mutex_lock(&fs_info->balance_mutex);
3969
3970                 if (fs_info->balance_ctl)
3971                         __cancel_balance(fs_info);
3972
3973                 mutex_unlock(&fs_info->volume_mutex);
3974         }
3975
3976         BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));
3977         atomic_dec(&fs_info->balance_cancel_req);
3978         mutex_unlock(&fs_info->balance_mutex);
3979         return 0;
3980 }
3981
3982 static int btrfs_uuid_scan_kthread(void *data)
3983 {
3984         struct btrfs_fs_info *fs_info = data;
3985         struct btrfs_root *root = fs_info->tree_root;
3986         struct btrfs_key key;
3987         struct btrfs_key max_key;
3988         struct btrfs_path *path = NULL;
3989         int ret = 0;
3990         struct extent_buffer *eb;
3991         int slot;
3992         struct btrfs_root_item root_item;
3993         u32 item_size;
3994         struct btrfs_trans_handle *trans = NULL;
3995
3996         path = btrfs_alloc_path();
3997         if (!path) {
3998                 ret = -ENOMEM;
3999                 goto out;
4000         }
4001
4002         key.objectid = 0;
4003         key.type = BTRFS_ROOT_ITEM_KEY;
4004         key.offset = 0;
4005
4006         max_key.objectid = (u64)-1;
4007         max_key.type = BTRFS_ROOT_ITEM_KEY;
4008         max_key.offset = (u64)-1;
4009
4010         while (1) {
4011                 ret = btrfs_search_forward(root, &key, path, 0);
4012                 if (ret) {
4013                         if (ret > 0)
4014                                 ret = 0;
4015                         break;
4016                 }
4017
4018                 if (key.type != BTRFS_ROOT_ITEM_KEY ||
4019                     (key.objectid < BTRFS_FIRST_FREE_OBJECTID &&
4020                      key.objectid != BTRFS_FS_TREE_OBJECTID) ||
4021                     key.objectid > BTRFS_LAST_FREE_OBJECTID)
4022                         goto skip;
4023
4024                 eb = path->nodes[0];
4025                 slot = path->slots[0];
4026                 item_size = btrfs_item_size_nr(eb, slot);
4027                 if (item_size < sizeof(root_item))
4028                         goto skip;
4029
4030                 read_extent_buffer(eb, &root_item,
4031                                    btrfs_item_ptr_offset(eb, slot),
4032                                    (int)sizeof(root_item));
4033                 if (btrfs_root_refs(&root_item) == 0)
4034                         goto skip;
4035
4036                 if (!btrfs_is_empty_uuid(root_item.uuid) ||
4037                     !btrfs_is_empty_uuid(root_item.received_uuid)) {
4038                         if (trans)
4039                                 goto update_tree;
4040
4041                         btrfs_release_path(path);
4042                         /*
4043                          * 1 - subvol uuid item
4044                          * 1 - received_subvol uuid item
4045                          */
4046                         trans = btrfs_start_transaction(fs_info->uuid_root, 2);
4047                         if (IS_ERR(trans)) {
4048                                 ret = PTR_ERR(trans);
4049                                 break;
4050                         }
4051                         continue;
4052                 } else {
4053                         goto skip;
4054                 }
4055 update_tree:
4056                 if (!btrfs_is_empty_uuid(root_item.uuid)) {
4057                         ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root,
4058                                                   root_item.uuid,
4059                                                   BTRFS_UUID_KEY_SUBVOL,
4060                                                   key.objectid);
4061                         if (ret < 0) {
4062                                 btrfs_warn(fs_info, "uuid_tree_add failed %d",
4063                                         ret);
4064                                 break;
4065                         }
4066                 }
4067
4068                 if (!btrfs_is_empty_uuid(root_item.received_uuid)) {
4069                         ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root,
4070                                                   root_item.received_uuid,
4071                                                  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
4072                                                   key.objectid);
4073                         if (ret < 0) {
4074                                 btrfs_warn(fs_info, "uuid_tree_add failed %d",
4075                                         ret);
4076                                 break;
4077                         }
4078                 }
4079
4080 skip:
4081                 if (trans) {
4082                         ret = btrfs_end_transaction(trans, fs_info->uuid_root);
4083                         trans = NULL;
4084                         if (ret)
4085                                 break;
4086                 }
4087
4088                 btrfs_release_path(path);
4089                 if (key.offset < (u64)-1) {
4090                         key.offset++;
4091                 } else if (key.type < BTRFS_ROOT_ITEM_KEY) {
4092                         key.offset = 0;
4093                         key.type = BTRFS_ROOT_ITEM_KEY;
4094                 } else if (key.objectid < (u64)-1) {
4095                         key.offset = 0;
4096                         key.type = BTRFS_ROOT_ITEM_KEY;
4097                         key.objectid++;
4098                 } else {
4099                         break;
4100                 }
4101                 cond_resched();
4102         }
4103
4104 out:
4105         btrfs_free_path(path);
4106         if (trans && !IS_ERR(trans))
4107                 btrfs_end_transaction(trans, fs_info->uuid_root);
4108         if (ret)
4109                 btrfs_warn(fs_info, "btrfs_uuid_scan_kthread failed %d", ret);
4110         else
4111                 fs_info->update_uuid_tree_gen = 1;
4112         up(&fs_info->uuid_tree_rescan_sem);
4113         return 0;
4114 }
4115
4116 /*
4117  * Callback for btrfs_uuid_tree_iterate().
4118  * returns:
4119  * 0    check succeeded, the entry is not outdated.
4120  * < 0  if an error occured.
4121  * > 0  if the check failed, which means the caller shall remove the entry.
4122  */
4123 static int btrfs_check_uuid_tree_entry(struct btrfs_fs_info *fs_info,
4124                                        u8 *uuid, u8 type, u64 subid)
4125 {
4126         struct btrfs_key key;
4127         int ret = 0;
4128         struct btrfs_root *subvol_root;
4129
4130         if (type != BTRFS_UUID_KEY_SUBVOL &&
4131             type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
4132                 goto out;
4133
4134         key.objectid = subid;
4135         key.type = BTRFS_ROOT_ITEM_KEY;
4136         key.offset = (u64)-1;
4137         subvol_root = btrfs_read_fs_root_no_name(fs_info, &key);
4138         if (IS_ERR(subvol_root)) {
4139                 ret = PTR_ERR(subvol_root);
4140                 if (ret == -ENOENT)
4141                         ret = 1;
4142                 goto out;
4143         }
4144
4145         switch (type) {
4146         case BTRFS_UUID_KEY_SUBVOL:
4147                 if (memcmp(uuid, subvol_root->root_item.uuid, BTRFS_UUID_SIZE))
4148                         ret = 1;
4149                 break;
4150         case BTRFS_UUID_KEY_RECEIVED_SUBVOL:
4151                 if (memcmp(uuid, subvol_root->root_item.received_uuid,
4152                            BTRFS_UUID_SIZE))
4153                         ret = 1;
4154                 break;
4155         }
4156
4157 out:
4158         return ret;
4159 }
4160
4161 static int btrfs_uuid_rescan_kthread(void *data)
4162 {
4163         struct btrfs_fs_info *fs_info = (struct btrfs_fs_info *)data;
4164         int ret;
4165
4166         /*
4167          * 1st step is to iterate through the existing UUID tree and
4168          * to delete all entries that contain outdated data.
4169          * 2nd step is to add all missing entries to the UUID tree.
4170          */
4171         ret = btrfs_uuid_tree_iterate(fs_info, btrfs_check_uuid_tree_entry);
4172         if (ret < 0) {
4173                 btrfs_warn(fs_info, "iterating uuid_tree failed %d", ret);
4174                 up(&fs_info->uuid_tree_rescan_sem);
4175                 return ret;
4176         }
4177         return btrfs_uuid_scan_kthread(data);
4178 }
4179
4180 int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info)
4181 {
4182         struct btrfs_trans_handle *trans;
4183         struct btrfs_root *tree_root = fs_info->tree_root;
4184         struct btrfs_root *uuid_root;
4185         struct task_struct *task;
4186         int ret;
4187
4188         /*
4189          * 1 - root node
4190          * 1 - root item
4191          */
4192         trans = btrfs_start_transaction(tree_root, 2);
4193         if (IS_ERR(trans))
4194                 return PTR_ERR(trans);
4195
4196         uuid_root = btrfs_create_tree(trans, fs_info,
4197                                       BTRFS_UUID_TREE_OBJECTID);
4198         if (IS_ERR(uuid_root)) {
4199                 ret = PTR_ERR(uuid_root);
4200                 btrfs_abort_transaction(trans, tree_root, ret);
4201                 return ret;
4202         }
4203
4204         fs_info->uuid_root = uuid_root;
4205
4206         ret = btrfs_commit_transaction(trans, tree_root);
4207         if (ret)
4208                 return ret;
4209
4210         down(&fs_info->uuid_tree_rescan_sem);
4211         task = kthread_run(btrfs_uuid_scan_kthread, fs_info, "btrfs-uuid");
4212         if (IS_ERR(task)) {
4213                 /* fs_info->update_uuid_tree_gen remains 0 in all error case */
4214                 btrfs_warn(fs_info, "failed to start uuid_scan task");
4215                 up(&fs_info->uuid_tree_rescan_sem);
4216                 return PTR_ERR(task);
4217         }
4218
4219         return 0;
4220 }
4221
4222 int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info)
4223 {
4224         struct task_struct *task;
4225
4226         down(&fs_info->uuid_tree_rescan_sem);
4227         task = kthread_run(btrfs_uuid_rescan_kthread, fs_info, "btrfs-uuid");
4228         if (IS_ERR(task)) {
4229                 /* fs_info->update_uuid_tree_gen remains 0 in all error case */
4230                 btrfs_warn(fs_info, "failed to start uuid_rescan task");
4231                 up(&fs_info->uuid_tree_rescan_sem);
4232                 return PTR_ERR(task);
4233         }
4234
4235         return 0;
4236 }
4237
4238 /*
4239  * shrinking a device means finding all of the device extents past
4240  * the new size, and then following the back refs to the chunks.
4241  * The chunk relocation code actually frees the device extent
4242  */
4243 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
4244 {
4245         struct btrfs_trans_handle *trans;
4246         struct btrfs_root *root = device->dev_root;
4247         struct btrfs_dev_extent *dev_extent = NULL;
4248         struct btrfs_path *path;
4249         u64 length;
4250         u64 chunk_offset;
4251         int ret;
4252         int slot;
4253         int failed = 0;
4254         bool retried = false;
4255         bool checked_pending_chunks = false;
4256         struct extent_buffer *l;
4257         struct btrfs_key key;
4258         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
4259         u64 old_total = btrfs_super_total_bytes(super_copy);
4260         u64 old_size = btrfs_device_get_total_bytes(device);
4261         u64 diff = old_size - new_size;
4262
4263         if (device->is_tgtdev_for_dev_replace)
4264                 return -EINVAL;
4265
4266         path = btrfs_alloc_path();
4267         if (!path)
4268                 return -ENOMEM;
4269
4270         path->reada = READA_FORWARD;
4271
4272         lock_chunks(root);
4273
4274         btrfs_device_set_total_bytes(device, new_size);
4275         if (device->writeable) {
4276                 device->fs_devices->total_rw_bytes -= diff;
4277                 spin_lock(&root->fs_info->free_chunk_lock);
4278                 root->fs_info->free_chunk_space -= diff;
4279                 spin_unlock(&root->fs_info->free_chunk_lock);
4280         }
4281         unlock_chunks(root);
4282
4283 again:
4284         key.objectid = device->devid;
4285         key.offset = (u64)-1;
4286         key.type = BTRFS_DEV_EXTENT_KEY;
4287
4288         do {
4289                 mutex_lock(&root->fs_info->delete_unused_bgs_mutex);
4290                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4291                 if (ret < 0) {
4292                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4293                         goto done;
4294                 }
4295
4296                 ret = btrfs_previous_item(root, path, 0, key.type);
4297                 if (ret)
4298                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4299                 if (ret < 0)
4300                         goto done;
4301                 if (ret) {
4302                         ret = 0;
4303                         btrfs_release_path(path);
4304                         break;
4305                 }
4306
4307                 l = path->nodes[0];
4308                 slot = path->slots[0];
4309                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
4310
4311                 if (key.objectid != device->devid) {
4312                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4313                         btrfs_release_path(path);
4314                         break;
4315                 }
4316
4317                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
4318                 length = btrfs_dev_extent_length(l, dev_extent);
4319
4320                 if (key.offset + length <= new_size) {
4321                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4322                         btrfs_release_path(path);
4323                         break;
4324                 }
4325
4326                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
4327                 btrfs_release_path(path);
4328
4329                 ret = btrfs_relocate_chunk(root, chunk_offset);
4330                 mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4331                 if (ret && ret != -ENOSPC)
4332                         goto done;
4333                 if (ret == -ENOSPC)
4334                         failed++;
4335         } while (key.offset-- > 0);
4336
4337         if (failed && !retried) {
4338                 failed = 0;
4339                 retried = true;
4340                 goto again;
4341         } else if (failed && retried) {
4342                 ret = -ENOSPC;
4343                 goto done;
4344         }
4345
4346         /* Shrinking succeeded, else we would be at "done". */
4347         trans = btrfs_start_transaction(root, 0);
4348         if (IS_ERR(trans)) {
4349                 ret = PTR_ERR(trans);
4350                 goto done;
4351         }
4352
4353         lock_chunks(root);
4354
4355         /*
4356          * We checked in the above loop all device extents that were already in
4357          * the device tree. However before we have updated the device's
4358          * total_bytes to the new size, we might have had chunk allocations that
4359          * have not complete yet (new block groups attached to transaction
4360          * handles), and therefore their device extents were not yet in the
4361          * device tree and we missed them in the loop above. So if we have any
4362          * pending chunk using a device extent that overlaps the device range
4363          * that we can not use anymore, commit the current transaction and
4364          * repeat the search on the device tree - this way we guarantee we will
4365          * not have chunks using device extents that end beyond 'new_size'.
4366          */
4367         if (!checked_pending_chunks) {
4368                 u64 start = new_size;
4369                 u64 len = old_size - new_size;
4370
4371                 if (contains_pending_extent(trans->transaction, device,
4372                                             &start, len)) {
4373                         unlock_chunks(root);
4374                         checked_pending_chunks = true;
4375                         failed = 0;
4376                         retried = false;
4377                         ret = btrfs_commit_transaction(trans, root);
4378                         if (ret)
4379                                 goto done;
4380                         goto again;
4381                 }
4382         }
4383
4384         btrfs_device_set_disk_total_bytes(device, new_size);
4385         if (list_empty(&device->resized_list))
4386                 list_add_tail(&device->resized_list,
4387                               &root->fs_info->fs_devices->resized_devices);
4388
4389         WARN_ON(diff > old_total);
4390         btrfs_set_super_total_bytes(super_copy, old_total - diff);
4391         unlock_chunks(root);
4392
4393         /* Now btrfs_update_device() will change the on-disk size. */
4394         ret = btrfs_update_device(trans, device);
4395         btrfs_end_transaction(trans, root);
4396 done:
4397         btrfs_free_path(path);
4398         if (ret) {
4399                 lock_chunks(root);
4400                 btrfs_device_set_total_bytes(device, old_size);
4401                 if (device->writeable)
4402                         device->fs_devices->total_rw_bytes += diff;
4403                 spin_lock(&root->fs_info->free_chunk_lock);
4404                 root->fs_info->free_chunk_space += diff;
4405                 spin_unlock(&root->fs_info->free_chunk_lock);
4406                 unlock_chunks(root);
4407         }
4408         return ret;
4409 }
4410
4411 static int btrfs_add_system_chunk(struct btrfs_root *root,
4412                            struct btrfs_key *key,
4413                            struct btrfs_chunk *chunk, int item_size)
4414 {
4415         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
4416         struct btrfs_disk_key disk_key;
4417         u32 array_size;
4418         u8 *ptr;
4419
4420         lock_chunks(root);
4421         array_size = btrfs_super_sys_array_size(super_copy);
4422         if (array_size + item_size + sizeof(disk_key)
4423                         > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE) {
4424                 unlock_chunks(root);
4425                 return -EFBIG;
4426         }
4427
4428         ptr = super_copy->sys_chunk_array + array_size;
4429         btrfs_cpu_key_to_disk(&disk_key, key);
4430         memcpy(ptr, &disk_key, sizeof(disk_key));
4431         ptr += sizeof(disk_key);
4432         memcpy(ptr, chunk, item_size);
4433         item_size += sizeof(disk_key);
4434         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
4435         unlock_chunks(root);
4436
4437         return 0;
4438 }
4439
4440 /*
4441  * sort the devices in descending order by max_avail, total_avail
4442  */
4443 static int btrfs_cmp_device_info(const void *a, const void *b)
4444 {
4445         const struct btrfs_device_info *di_a = a;
4446         const struct btrfs_device_info *di_b = b;
4447
4448         if (di_a->max_avail > di_b->max_avail)
4449                 return -1;
4450         if (di_a->max_avail < di_b->max_avail)
4451                 return 1;
4452         if (di_a->total_avail > di_b->total_avail)
4453                 return -1;
4454         if (di_a->total_avail < di_b->total_avail)
4455                 return 1;
4456         return 0;
4457 }
4458
4459 static u32 find_raid56_stripe_len(u32 data_devices, u32 dev_stripe_target)
4460 {
4461         /* TODO allow them to set a preferred stripe size */
4462         return SZ_64K;
4463 }
4464
4465 static void check_raid56_incompat_flag(struct btrfs_fs_info *info, u64 type)
4466 {
4467         if (!(type & BTRFS_BLOCK_GROUP_RAID56_MASK))
4468                 return;
4469
4470         btrfs_set_fs_incompat(info, RAID56);
4471 }
4472
4473 #define BTRFS_MAX_DEVS(r) ((BTRFS_LEAF_DATA_SIZE(r)             \
4474                         - sizeof(struct btrfs_item)             \
4475                         - sizeof(struct btrfs_chunk))           \
4476                         / sizeof(struct btrfs_stripe) + 1)
4477
4478 #define BTRFS_MAX_DEVS_SYS_CHUNK ((BTRFS_SYSTEM_CHUNK_ARRAY_SIZE        \
4479                                 - 2 * sizeof(struct btrfs_disk_key)     \
4480                                 - 2 * sizeof(struct btrfs_chunk))       \
4481                                 / sizeof(struct btrfs_stripe) + 1)
4482
4483 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
4484                                struct btrfs_root *extent_root, u64 start,
4485                                u64 type)
4486 {
4487         struct btrfs_fs_info *info = extent_root->fs_info;
4488         struct btrfs_fs_devices *fs_devices = info->fs_devices;
4489         struct list_head *cur;
4490         struct map_lookup *map = NULL;
4491         struct extent_map_tree *em_tree;
4492         struct extent_map *em;
4493         struct btrfs_device_info *devices_info = NULL;
4494         u64 total_avail;
4495         int num_stripes;        /* total number of stripes to allocate */
4496         int data_stripes;       /* number of stripes that count for
4497                                    block group size */
4498         int sub_stripes;        /* sub_stripes info for map */
4499         int dev_stripes;        /* stripes per dev */
4500         int devs_max;           /* max devs to use */
4501         int devs_min;           /* min devs needed */
4502         int devs_increment;     /* ndevs has to be a multiple of this */
4503         int ncopies;            /* how many copies to data has */
4504         int ret;
4505         u64 max_stripe_size;
4506         u64 max_chunk_size;
4507         u64 stripe_size;
4508         u64 num_bytes;
4509         u64 raid_stripe_len = BTRFS_STRIPE_LEN;
4510         int ndevs;
4511         int i;
4512         int j;
4513         int index;
4514
4515         BUG_ON(!alloc_profile_is_valid(type, 0));
4516
4517         if (list_empty(&fs_devices->alloc_list))
4518                 return -ENOSPC;
4519
4520         index = __get_raid_index(type);
4521
4522         sub_stripes = btrfs_raid_array[index].sub_stripes;
4523         dev_stripes = btrfs_raid_array[index].dev_stripes;
4524         devs_max = btrfs_raid_array[index].devs_max;
4525         devs_min = btrfs_raid_array[index].devs_min;
4526         devs_increment = btrfs_raid_array[index].devs_increment;
4527         ncopies = btrfs_raid_array[index].ncopies;
4528
4529         if (type & BTRFS_BLOCK_GROUP_DATA) {
4530                 max_stripe_size = SZ_1G;
4531                 max_chunk_size = 10 * max_stripe_size;
4532                 if (!devs_max)
4533                         devs_max = BTRFS_MAX_DEVS(info->chunk_root);
4534         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
4535                 /* for larger filesystems, use larger metadata chunks */
4536                 if (fs_devices->total_rw_bytes > 50ULL * SZ_1G)
4537                         max_stripe_size = SZ_1G;
4538                 else
4539                         max_stripe_size = SZ_256M;
4540                 max_chunk_size = max_stripe_size;
4541                 if (!devs_max)
4542                         devs_max = BTRFS_MAX_DEVS(info->chunk_root);
4543         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
4544                 max_stripe_size = SZ_32M;
4545                 max_chunk_size = 2 * max_stripe_size;
4546                 if (!devs_max)
4547                         devs_max = BTRFS_MAX_DEVS_SYS_CHUNK;
4548         } else {
4549                 btrfs_err(info, "invalid chunk type 0x%llx requested",
4550                        type);
4551                 BUG_ON(1);
4552         }
4553
4554         /* we don't want a chunk larger than 10% of writeable space */
4555         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
4556                              max_chunk_size);
4557
4558         devices_info = kcalloc(fs_devices->rw_devices, sizeof(*devices_info),
4559                                GFP_NOFS);
4560         if (!devices_info)
4561                 return -ENOMEM;
4562
4563         cur = fs_devices->alloc_list.next;
4564
4565         /*
4566          * in the first pass through the devices list, we gather information
4567          * about the available holes on each device.
4568          */
4569         ndevs = 0;
4570         while (cur != &fs_devices->alloc_list) {
4571                 struct btrfs_device *device;
4572                 u64 max_avail;
4573                 u64 dev_offset;
4574
4575                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
4576
4577                 cur = cur->next;
4578
4579                 if (!device->writeable) {
4580                         WARN(1, KERN_ERR
4581                                "BTRFS: read-only device in alloc_list\n");
4582                         continue;
4583                 }
4584
4585                 if (!device->in_fs_metadata ||
4586                     device->is_tgtdev_for_dev_replace)
4587                         continue;
4588
4589                 if (device->total_bytes > device->bytes_used)
4590                         total_avail = device->total_bytes - device->bytes_used;
4591                 else
4592                         total_avail = 0;
4593
4594                 /* If there is no space on this device, skip it. */
4595                 if (total_avail == 0)
4596                         continue;
4597
4598                 ret = find_free_dev_extent(trans, device,
4599                                            max_stripe_size * dev_stripes,
4600                                            &dev_offset, &max_avail);
4601                 if (ret && ret != -ENOSPC)
4602                         goto error;
4603
4604                 if (ret == 0)
4605                         max_avail = max_stripe_size * dev_stripes;
4606
4607                 if (max_avail < BTRFS_STRIPE_LEN * dev_stripes)
4608                         continue;
4609
4610                 if (ndevs == fs_devices->rw_devices) {
4611                         WARN(1, "%s: found more than %llu devices\n",
4612                              __func__, fs_devices->rw_devices);
4613                         break;
4614                 }
4615                 devices_info[ndevs].dev_offset = dev_offset;
4616                 devices_info[ndevs].max_avail = max_avail;
4617                 devices_info[ndevs].total_avail = total_avail;
4618                 devices_info[ndevs].dev = device;
4619                 ++ndevs;
4620         }
4621
4622         /*
4623          * now sort the devices by hole size / available space
4624          */
4625         sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
4626              btrfs_cmp_device_info, NULL);
4627
4628         /* round down to number of usable stripes */
4629         ndevs -= ndevs % devs_increment;
4630
4631         if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
4632                 ret = -ENOSPC;
4633                 goto error;
4634         }
4635
4636         if (devs_max && ndevs > devs_max)
4637                 ndevs = devs_max;
4638         /*
4639          * the primary goal is to maximize the number of stripes, so use as many
4640          * devices as possible, even if the stripes are not maximum sized.
4641          */
4642         stripe_size = devices_info[ndevs-1].max_avail;
4643         num_stripes = ndevs * dev_stripes;
4644
4645         /*
4646          * this will have to be fixed for RAID1 and RAID10 over
4647          * more drives
4648          */
4649         data_stripes = num_stripes / ncopies;
4650
4651         if (type & BTRFS_BLOCK_GROUP_RAID5) {
4652                 raid_stripe_len = find_raid56_stripe_len(ndevs - 1,
4653                                  btrfs_super_stripesize(info->super_copy));
4654                 data_stripes = num_stripes - 1;
4655         }
4656         if (type & BTRFS_BLOCK_GROUP_RAID6) {
4657                 raid_stripe_len = find_raid56_stripe_len(ndevs - 2,
4658                                  btrfs_super_stripesize(info->super_copy));
4659                 data_stripes = num_stripes - 2;
4660         }
4661
4662         /*
4663          * Use the number of data stripes to figure out how big this chunk
4664          * is really going to be in terms of logical address space,
4665          * and compare that answer with the max chunk size
4666          */
4667         if (stripe_size * data_stripes > max_chunk_size) {
4668                 u64 mask = (1ULL << 24) - 1;
4669
4670                 stripe_size = div_u64(max_chunk_size, data_stripes);
4671
4672                 /* bump the answer up to a 16MB boundary */
4673                 stripe_size = (stripe_size + mask) & ~mask;
4674
4675                 /* but don't go higher than the limits we found
4676                  * while searching for free extents
4677                  */
4678                 if (stripe_size > devices_info[ndevs-1].max_avail)
4679                         stripe_size = devices_info[ndevs-1].max_avail;
4680         }
4681
4682         stripe_size = div_u64(stripe_size, dev_stripes);
4683
4684         /* align to BTRFS_STRIPE_LEN */
4685         stripe_size = div_u64(stripe_size, raid_stripe_len);
4686         stripe_size *= raid_stripe_len;
4687
4688         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
4689         if (!map) {
4690                 ret = -ENOMEM;
4691                 goto error;
4692         }
4693         map->num_stripes = num_stripes;
4694
4695         for (i = 0; i < ndevs; ++i) {
4696                 for (j = 0; j < dev_stripes; ++j) {
4697                         int s = i * dev_stripes + j;
4698                         map->stripes[s].dev = devices_info[i].dev;
4699                         map->stripes[s].physical = devices_info[i].dev_offset +
4700                                                    j * stripe_size;
4701                 }
4702         }
4703         map->sector_size = extent_root->sectorsize;
4704         map->stripe_len = raid_stripe_len;
4705         map->io_align = raid_stripe_len;
4706         map->io_width = raid_stripe_len;
4707         map->type = type;
4708         map->sub_stripes = sub_stripes;
4709
4710         num_bytes = stripe_size * data_stripes;
4711
4712         trace_btrfs_chunk_alloc(info->chunk_root, map, start, num_bytes);
4713
4714         em = alloc_extent_map();
4715         if (!em) {
4716                 kfree(map);
4717                 ret = -ENOMEM;
4718                 goto error;
4719         }
4720         set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
4721         em->bdev = (struct block_device *)map;
4722         em->start = start;
4723         em->len = num_bytes;
4724         em->block_start = 0;
4725         em->block_len = em->len;
4726         em->orig_block_len = stripe_size;
4727
4728         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
4729         write_lock(&em_tree->lock);
4730         ret = add_extent_mapping(em_tree, em, 0);
4731         if (!ret) {
4732                 list_add_tail(&em->list, &trans->transaction->pending_chunks);
4733                 atomic_inc(&em->refs);
4734         }
4735         write_unlock(&em_tree->lock);
4736         if (ret) {
4737                 free_extent_map(em);
4738                 goto error;
4739         }
4740
4741         ret = btrfs_make_block_group(trans, extent_root, 0, type,
4742                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
4743                                      start, num_bytes);
4744         if (ret)
4745                 goto error_del_extent;
4746
4747         for (i = 0; i < map->num_stripes; i++) {
4748                 num_bytes = map->stripes[i].dev->bytes_used + stripe_size;
4749                 btrfs_device_set_bytes_used(map->stripes[i].dev, num_bytes);
4750         }
4751
4752         spin_lock(&extent_root->fs_info->free_chunk_lock);
4753         extent_root->fs_info->free_chunk_space -= (stripe_size *
4754                                                    map->num_stripes);
4755         spin_unlock(&extent_root->fs_info->free_chunk_lock);
4756
4757         free_extent_map(em);
4758         check_raid56_incompat_flag(extent_root->fs_info, type);
4759
4760         kfree(devices_info);
4761         return 0;
4762
4763 error_del_extent:
4764         write_lock(&em_tree->lock);
4765         remove_extent_mapping(em_tree, em);
4766         write_unlock(&em_tree->lock);
4767
4768         /* One for our allocation */
4769         free_extent_map(em);
4770         /* One for the tree reference */
4771         free_extent_map(em);
4772         /* One for the pending_chunks list reference */
4773         free_extent_map(em);
4774 error:
4775         kfree(devices_info);
4776         return ret;
4777 }
4778
4779 int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
4780                                 struct btrfs_root *extent_root,
4781                                 u64 chunk_offset, u64 chunk_size)
4782 {
4783         struct btrfs_key key;
4784         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
4785         struct btrfs_device *device;
4786         struct btrfs_chunk *chunk;
4787         struct btrfs_stripe *stripe;
4788         struct extent_map_tree *em_tree;
4789         struct extent_map *em;
4790         struct map_lookup *map;
4791         size_t item_size;
4792         u64 dev_offset;
4793         u64 stripe_size;
4794         int i = 0;
4795         int ret = 0;
4796
4797         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
4798         read_lock(&em_tree->lock);
4799         em = lookup_extent_mapping(em_tree, chunk_offset, chunk_size);
4800         read_unlock(&em_tree->lock);
4801
4802         if (!em) {
4803                 btrfs_crit(extent_root->fs_info, "unable to find logical "
4804                            "%Lu len %Lu", chunk_offset, chunk_size);
4805                 return -EINVAL;
4806         }
4807
4808         if (em->start != chunk_offset || em->len != chunk_size) {
4809                 btrfs_crit(extent_root->fs_info, "found a bad mapping, wanted"
4810                           " %Lu-%Lu, found %Lu-%Lu", chunk_offset,
4811                           chunk_size, em->start, em->len);
4812                 free_extent_map(em);
4813                 return -EINVAL;
4814         }
4815
4816         map = (struct map_lookup *)em->bdev;
4817         item_size = btrfs_chunk_item_size(map->num_stripes);
4818         stripe_size = em->orig_block_len;
4819
4820         chunk = kzalloc(item_size, GFP_NOFS);
4821         if (!chunk) {
4822                 ret = -ENOMEM;
4823                 goto out;
4824         }
4825
4826         /*
4827          * Take the device list mutex to prevent races with the final phase of
4828          * a device replace operation that replaces the device object associated
4829          * with the map's stripes, because the device object's id can change
4830          * at any time during that final phase of the device replace operation
4831          * (dev-replace.c:btrfs_dev_replace_finishing()).
4832          */
4833         mutex_lock(&chunk_root->fs_info->fs_devices->device_list_mutex);
4834         for (i = 0; i < map->num_stripes; i++) {
4835                 device = map->stripes[i].dev;
4836                 dev_offset = map->stripes[i].physical;
4837
4838                 ret = btrfs_update_device(trans, device);
4839                 if (ret)
4840                         break;
4841                 ret = btrfs_alloc_dev_extent(trans, device,
4842                                              chunk_root->root_key.objectid,
4843                                              BTRFS_FIRST_CHUNK_TREE_OBJECTID,
4844                                              chunk_offset, dev_offset,
4845                                              stripe_size);
4846                 if (ret)
4847                         break;
4848         }
4849         if (ret) {
4850                 mutex_unlock(&chunk_root->fs_info->fs_devices->device_list_mutex);
4851                 goto out;
4852         }
4853
4854         stripe = &chunk->stripe;
4855         for (i = 0; i < map->num_stripes; i++) {
4856                 device = map->stripes[i].dev;
4857                 dev_offset = map->stripes[i].physical;
4858
4859                 btrfs_set_stack_stripe_devid(stripe, device->devid);
4860                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
4861                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
4862                 stripe++;
4863         }
4864         mutex_unlock(&chunk_root->fs_info->fs_devices->device_list_mutex);
4865
4866         btrfs_set_stack_chunk_length(chunk, chunk_size);
4867         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
4868         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
4869         btrfs_set_stack_chunk_type(chunk, map->type);
4870         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
4871         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
4872         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
4873         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
4874         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
4875
4876         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
4877         key.type = BTRFS_CHUNK_ITEM_KEY;
4878         key.offset = chunk_offset;
4879
4880         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
4881         if (ret == 0 && map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
4882                 /*
4883                  * TODO: Cleanup of inserted chunk root in case of
4884                  * failure.
4885                  */
4886                 ret = btrfs_add_system_chunk(chunk_root, &key, chunk,
4887                                              item_size);
4888         }
4889
4890 out:
4891         kfree(chunk);
4892         free_extent_map(em);
4893         return ret;
4894 }
4895
4896 /*
4897  * Chunk allocation falls into two parts. The first part does works
4898  * that make the new allocated chunk useable, but not do any operation
4899  * that modifies the chunk tree. The second part does the works that
4900  * require modifying the chunk tree. This division is important for the
4901  * bootstrap process of adding storage to a seed btrfs.
4902  */
4903 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
4904                       struct btrfs_root *extent_root, u64 type)
4905 {
4906         u64 chunk_offset;
4907
4908         ASSERT(mutex_is_locked(&extent_root->fs_info->chunk_mutex));
4909         chunk_offset = find_next_chunk(extent_root->fs_info);
4910         return __btrfs_alloc_chunk(trans, extent_root, chunk_offset, type);
4911 }
4912
4913 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
4914                                          struct btrfs_root *root,
4915                                          struct btrfs_device *device)
4916 {
4917         u64 chunk_offset;
4918         u64 sys_chunk_offset;
4919         u64 alloc_profile;
4920         struct btrfs_fs_info *fs_info = root->fs_info;
4921         struct btrfs_root *extent_root = fs_info->extent_root;
4922         int ret;
4923
4924         chunk_offset = find_next_chunk(fs_info);
4925         alloc_profile = btrfs_get_alloc_profile(extent_root, 0);
4926         ret = __btrfs_alloc_chunk(trans, extent_root, chunk_offset,
4927                                   alloc_profile);
4928         if (ret)
4929                 return ret;
4930
4931         sys_chunk_offset = find_next_chunk(root->fs_info);
4932         alloc_profile = btrfs_get_alloc_profile(fs_info->chunk_root, 0);
4933         ret = __btrfs_alloc_chunk(trans, extent_root, sys_chunk_offset,
4934                                   alloc_profile);
4935         return ret;
4936 }
4937
4938 static inline int btrfs_chunk_max_errors(struct map_lookup *map)
4939 {
4940         int max_errors;
4941
4942         if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
4943                          BTRFS_BLOCK_GROUP_RAID10 |
4944                          BTRFS_BLOCK_GROUP_RAID5 |
4945                          BTRFS_BLOCK_GROUP_DUP)) {
4946                 max_errors = 1;
4947         } else if (map->type & BTRFS_BLOCK_GROUP_RAID6) {
4948                 max_errors = 2;
4949         } else {
4950                 max_errors = 0;
4951         }
4952
4953         return max_errors;
4954 }
4955
4956 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
4957 {
4958         struct extent_map *em;
4959         struct map_lookup *map;
4960         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
4961         int readonly = 0;
4962         int miss_ndevs = 0;
4963         int i;
4964
4965         read_lock(&map_tree->map_tree.lock);
4966         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
4967         read_unlock(&map_tree->map_tree.lock);
4968         if (!em)
4969                 return 1;
4970
4971         map = (struct map_lookup *)em->bdev;
4972         for (i = 0; i < map->num_stripes; i++) {
4973                 if (map->stripes[i].dev->missing) {
4974                         miss_ndevs++;
4975                         continue;
4976                 }
4977
4978                 if (!map->stripes[i].dev->writeable) {
4979                         readonly = 1;
4980                         goto end;
4981                 }
4982         }
4983
4984         /*
4985          * If the number of missing devices is larger than max errors,
4986          * we can not write the data into that chunk successfully, so
4987          * set it readonly.
4988          */
4989         if (miss_ndevs > btrfs_chunk_max_errors(map))
4990                 readonly = 1;
4991 end:
4992         free_extent_map(em);
4993         return readonly;
4994 }
4995
4996 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
4997 {
4998         extent_map_tree_init(&tree->map_tree);
4999 }
5000
5001 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
5002 {
5003         struct extent_map *em;
5004
5005         while (1) {
5006                 write_lock(&tree->map_tree.lock);
5007                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
5008                 if (em)
5009                         remove_extent_mapping(&tree->map_tree, em);
5010                 write_unlock(&tree->map_tree.lock);
5011                 if (!em)
5012                         break;
5013                 /* once for us */
5014                 free_extent_map(em);
5015                 /* once for the tree */
5016                 free_extent_map(em);
5017         }
5018 }
5019
5020 int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
5021 {
5022         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
5023         struct extent_map *em;
5024         struct map_lookup *map;
5025         struct extent_map_tree *em_tree = &map_tree->map_tree;
5026         int ret;
5027
5028         read_lock(&em_tree->lock);
5029         em = lookup_extent_mapping(em_tree, logical, len);
5030         read_unlock(&em_tree->lock);
5031
5032         /*
5033          * We could return errors for these cases, but that could get ugly and
5034          * we'd probably do the same thing which is just not do anything else
5035          * and exit, so return 1 so the callers don't try to use other copies.
5036          */
5037         if (!em) {
5038                 btrfs_crit(fs_info, "No mapping for %Lu-%Lu", logical,
5039                             logical+len);
5040                 return 1;
5041         }
5042
5043         if (em->start > logical || em->start + em->len < logical) {
5044                 btrfs_crit(fs_info, "Invalid mapping for %Lu-%Lu, got "
5045                             "%Lu-%Lu", logical, logical+len, em->start,
5046                             em->start + em->len);
5047                 free_extent_map(em);
5048                 return 1;
5049         }
5050
5051         map = (struct map_lookup *)em->bdev;
5052         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
5053                 ret = map->num_stripes;
5054         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
5055                 ret = map->sub_stripes;
5056         else if (map->type & BTRFS_BLOCK_GROUP_RAID5)
5057                 ret = 2;
5058         else if (map->type & BTRFS_BLOCK_GROUP_RAID6)
5059                 ret = 3;
5060         else
5061                 ret = 1;
5062         free_extent_map(em);
5063
5064         btrfs_dev_replace_lock(&fs_info->dev_replace);
5065         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))
5066                 ret++;
5067         btrfs_dev_replace_unlock(&fs_info->dev_replace);
5068
5069         return ret;
5070 }
5071
5072 unsigned long btrfs_full_stripe_len(struct btrfs_root *root,
5073                                     struct btrfs_mapping_tree *map_tree,
5074                                     u64 logical)
5075 {
5076         struct extent_map *em;
5077         struct map_lookup *map;
5078         struct extent_map_tree *em_tree = &map_tree->map_tree;
5079         unsigned long len = root->sectorsize;
5080
5081         read_lock(&em_tree->lock);
5082         em = lookup_extent_mapping(em_tree, logical, len);
5083         read_unlock(&em_tree->lock);
5084         BUG_ON(!em);
5085
5086         BUG_ON(em->start > logical || em->start + em->len < logical);
5087         map = (struct map_lookup *)em->bdev;
5088         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
5089                 len = map->stripe_len * nr_data_stripes(map);
5090         free_extent_map(em);
5091         return len;
5092 }
5093
5094 int btrfs_is_parity_mirror(struct btrfs_mapping_tree *map_tree,
5095                            u64 logical, u64 len, int mirror_num)
5096 {
5097         struct extent_map *em;
5098         struct map_lookup *map;
5099         struct extent_map_tree *em_tree = &map_tree->map_tree;
5100         int ret = 0;
5101
5102         read_lock(&em_tree->lock);
5103         em = lookup_extent_mapping(em_tree, logical, len);
5104         read_unlock(&em_tree->lock);
5105         BUG_ON(!em);
5106
5107         BUG_ON(em->start > logical || em->start + em->len < logical);
5108         map = (struct map_lookup *)em->bdev;
5109         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
5110                 ret = 1;
5111         free_extent_map(em);
5112         return ret;
5113 }
5114
5115 static int find_live_mirror(struct btrfs_fs_info *fs_info,
5116                             struct map_lookup *map, int first, int num,
5117                             int optimal, int dev_replace_is_ongoing)
5118 {
5119         int i;
5120         int tolerance;
5121         struct btrfs_device *srcdev;
5122
5123         if (dev_replace_is_ongoing &&
5124             fs_info->dev_replace.cont_reading_from_srcdev_mode ==
5125              BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID)
5126                 srcdev = fs_info->dev_replace.srcdev;
5127         else
5128                 srcdev = NULL;
5129
5130         /*
5131          * try to avoid the drive that is the source drive for a
5132          * dev-replace procedure, only choose it if no other non-missing
5133          * mirror is available
5134          */
5135         for (tolerance = 0; tolerance < 2; tolerance++) {
5136                 if (map->stripes[optimal].dev->bdev &&
5137                     (tolerance || map->stripes[optimal].dev != srcdev))
5138                         return optimal;
5139                 for (i = first; i < first + num; i++) {
5140                         if (map->stripes[i].dev->bdev &&
5141                             (tolerance || map->stripes[i].dev != srcdev))
5142                                 return i;
5143                 }
5144         }
5145
5146         /* we couldn't find one that doesn't fail.  Just return something
5147          * and the io error handling code will clean up eventually
5148          */
5149         return optimal;
5150 }
5151
5152 static inline int parity_smaller(u64 a, u64 b)
5153 {
5154         return a > b;
5155 }
5156
5157 /* Bubble-sort the stripe set to put the parity/syndrome stripes last */
5158 static void sort_parity_stripes(struct btrfs_bio *bbio, int num_stripes)
5159 {
5160         struct btrfs_bio_stripe s;
5161         int i;
5162         u64 l;
5163         int again = 1;
5164
5165         while (again) {
5166                 again = 0;
5167                 for (i = 0; i < num_stripes - 1; i++) {
5168                         if (parity_smaller(bbio->raid_map[i],
5169                                            bbio->raid_map[i+1])) {
5170                                 s = bbio->stripes[i];
5171                                 l = bbio->raid_map[i];
5172                                 bbio->stripes[i] = bbio->stripes[i+1];
5173                                 bbio->raid_map[i] = bbio->raid_map[i+1];
5174                                 bbio->stripes[i+1] = s;
5175                                 bbio->raid_map[i+1] = l;
5176
5177                                 again = 1;
5178                         }
5179                 }
5180         }
5181 }
5182
5183 static struct btrfs_bio *alloc_btrfs_bio(int total_stripes, int real_stripes)
5184 {
5185         struct btrfs_bio *bbio = kzalloc(
5186                  /* the size of the btrfs_bio */
5187                 sizeof(struct btrfs_bio) +
5188                 /* plus the variable array for the stripes */
5189                 sizeof(struct btrfs_bio_stripe) * (total_stripes) +
5190                 /* plus the variable array for the tgt dev */
5191                 sizeof(int) * (real_stripes) +
5192                 /*
5193                  * plus the raid_map, which includes both the tgt dev
5194                  * and the stripes
5195                  */
5196                 sizeof(u64) * (total_stripes),
5197                 GFP_NOFS|__GFP_NOFAIL);
5198
5199         atomic_set(&bbio->error, 0);
5200         atomic_set(&bbio->refs, 1);
5201
5202         return bbio;
5203 }
5204
5205 void btrfs_get_bbio(struct btrfs_bio *bbio)
5206 {
5207         WARN_ON(!atomic_read(&bbio->refs));
5208         atomic_inc(&bbio->refs);
5209 }
5210
5211 void btrfs_put_bbio(struct btrfs_bio *bbio)
5212 {
5213         if (!bbio)
5214                 return;
5215         if (atomic_dec_and_test(&bbio->refs))
5216                 kfree(bbio);
5217 }
5218
5219 static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
5220                              u64 logical, u64 *length,
5221                              struct btrfs_bio **bbio_ret,
5222                              int mirror_num, int need_raid_map)
5223 {
5224         struct extent_map *em;
5225         struct map_lookup *map;
5226         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
5227         struct extent_map_tree *em_tree = &map_tree->map_tree;
5228         u64 offset;
5229         u64 stripe_offset;
5230         u64 stripe_end_offset;
5231         u64 stripe_nr;
5232         u64 stripe_nr_orig;
5233         u64 stripe_nr_end;
5234         u64 stripe_len;
5235         u32 stripe_index;
5236         int i;
5237         int ret = 0;
5238         int num_stripes;
5239         int max_errors = 0;
5240         int tgtdev_indexes = 0;
5241         struct btrfs_bio *bbio = NULL;
5242         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
5243         int dev_replace_is_ongoing = 0;
5244         int num_alloc_stripes;
5245         int patch_the_first_stripe_for_dev_replace = 0;
5246         u64 physical_to_patch_in_first_stripe = 0;
5247         u64 raid56_full_stripe_start = (u64)-1;
5248
5249         read_lock(&em_tree->lock);
5250         em = lookup_extent_mapping(em_tree, logical, *length);
5251         read_unlock(&em_tree->lock);
5252
5253         if (!em) {
5254                 btrfs_crit(fs_info, "unable to find logical %llu len %llu",
5255                         logical, *length);
5256                 return -EINVAL;
5257         }
5258
5259         if (em->start > logical || em->start + em->len < logical) {
5260                 btrfs_crit(fs_info, "found a bad mapping, wanted %Lu, "
5261                            "found %Lu-%Lu", logical, em->start,
5262                            em->start + em->len);
5263                 free_extent_map(em);
5264                 return -EINVAL;
5265         }
5266
5267         map = (struct map_lookup *)em->bdev;
5268         offset = logical - em->start;
5269
5270         stripe_len = map->stripe_len;
5271         stripe_nr = offset;
5272         /*
5273          * stripe_nr counts the total number of stripes we have to stride
5274          * to get to this block
5275          */
5276         stripe_nr = div64_u64(stripe_nr, stripe_len);
5277
5278         stripe_offset = stripe_nr * stripe_len;
5279         BUG_ON(offset < stripe_offset);
5280
5281         /* stripe_offset is the offset of this block in its stripe*/
5282         stripe_offset = offset - stripe_offset;
5283
5284         /* if we're here for raid56, we need to know the stripe aligned start */
5285         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5286                 unsigned long full_stripe_len = stripe_len * nr_data_stripes(map);
5287                 raid56_full_stripe_start = offset;
5288
5289                 /* allow a write of a full stripe, but make sure we don't
5290                  * allow straddling of stripes
5291                  */
5292                 raid56_full_stripe_start = div64_u64(raid56_full_stripe_start,
5293                                 full_stripe_len);
5294                 raid56_full_stripe_start *= full_stripe_len;
5295         }
5296
5297         if (rw & REQ_DISCARD) {
5298                 /* we don't discard raid56 yet */
5299                 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5300                         ret = -EOPNOTSUPP;
5301                         goto out;
5302                 }
5303                 *length = min_t(u64, em->len - offset, *length);
5304         } else if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
5305                 u64 max_len;
5306                 /* For writes to RAID[56], allow a full stripeset across all disks.
5307                    For other RAID types and for RAID[56] reads, just allow a single
5308                    stripe (on a single disk). */
5309                 if ((map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) &&
5310                     (rw & REQ_WRITE)) {
5311                         max_len = stripe_len * nr_data_stripes(map) -
5312                                 (offset - raid56_full_stripe_start);
5313                 } else {
5314                         /* we limit the length of each bio to what fits in a stripe */
5315                         max_len = stripe_len - stripe_offset;
5316                 }
5317                 *length = min_t(u64, em->len - offset, max_len);
5318         } else {
5319                 *length = em->len - offset;
5320         }
5321
5322         /* This is for when we're called from btrfs_merge_bio_hook() and all
5323            it cares about is the length */
5324         if (!bbio_ret)
5325                 goto out;
5326
5327         btrfs_dev_replace_lock(dev_replace);
5328         dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(dev_replace);
5329         if (!dev_replace_is_ongoing)
5330                 btrfs_dev_replace_unlock(dev_replace);
5331
5332         if (dev_replace_is_ongoing && mirror_num == map->num_stripes + 1 &&
5333             !(rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) &&
5334             dev_replace->tgtdev != NULL) {
5335                 /*
5336                  * in dev-replace case, for repair case (that's the only
5337                  * case where the mirror is selected explicitly when
5338                  * calling btrfs_map_block), blocks left of the left cursor
5339                  * can also be read from the target drive.
5340                  * For REQ_GET_READ_MIRRORS, the target drive is added as
5341                  * the last one to the array of stripes. For READ, it also
5342                  * needs to be supported using the same mirror number.
5343                  * If the requested block is not left of the left cursor,
5344                  * EIO is returned. This can happen because btrfs_num_copies()
5345                  * returns one more in the dev-replace case.
5346                  */
5347                 u64 tmp_length = *length;
5348                 struct btrfs_bio *tmp_bbio = NULL;
5349                 int tmp_num_stripes;
5350                 u64 srcdev_devid = dev_replace->srcdev->devid;
5351                 int index_srcdev = 0;
5352                 int found = 0;
5353                 u64 physical_of_found = 0;
5354
5355                 ret = __btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS,
5356                              logical, &tmp_length, &tmp_bbio, 0, 0);
5357                 if (ret) {
5358                         WARN_ON(tmp_bbio != NULL);
5359                         goto out;
5360                 }
5361
5362                 tmp_num_stripes = tmp_bbio->num_stripes;
5363                 if (mirror_num > tmp_num_stripes) {
5364                         /*
5365                          * REQ_GET_READ_MIRRORS does not contain this
5366                          * mirror, that means that the requested area
5367                          * is not left of the left cursor
5368                          */
5369                         ret = -EIO;
5370                         btrfs_put_bbio(tmp_bbio);
5371                         goto out;
5372                 }
5373
5374                 /*
5375                  * process the rest of the function using the mirror_num
5376                  * of the source drive. Therefore look it up first.
5377                  * At the end, patch the device pointer to the one of the
5378                  * target drive.
5379                  */
5380                 for (i = 0; i < tmp_num_stripes; i++) {
5381                         if (tmp_bbio->stripes[i].dev->devid == srcdev_devid) {
5382                                 /*
5383                                  * In case of DUP, in order to keep it
5384                                  * simple, only add the mirror with the
5385                                  * lowest physical address
5386                                  */
5387                                 if (found &&
5388                                     physical_of_found <=
5389                                      tmp_bbio->stripes[i].physical)
5390                                         continue;
5391                                 index_srcdev = i;
5392                                 found = 1;
5393                                 physical_of_found =
5394                                         tmp_bbio->stripes[i].physical;
5395                         }
5396                 }
5397
5398                 if (found) {
5399                         mirror_num = index_srcdev + 1;
5400                         patch_the_first_stripe_for_dev_replace = 1;
5401                         physical_to_patch_in_first_stripe = physical_of_found;
5402                 } else {
5403                         WARN_ON(1);
5404                         ret = -EIO;
5405                         btrfs_put_bbio(tmp_bbio);
5406                         goto out;
5407                 }
5408
5409                 btrfs_put_bbio(tmp_bbio);
5410         } else if (mirror_num > map->num_stripes) {
5411                 mirror_num = 0;
5412         }
5413
5414         num_stripes = 1;
5415         stripe_index = 0;
5416         stripe_nr_orig = stripe_nr;
5417         stripe_nr_end = ALIGN(offset + *length, map->stripe_len);
5418         stripe_nr_end = div_u64(stripe_nr_end, map->stripe_len);
5419         stripe_end_offset = stripe_nr_end * map->stripe_len -
5420                             (offset + *length);
5421
5422         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
5423                 if (rw & REQ_DISCARD)
5424                         num_stripes = min_t(u64, map->num_stripes,
5425                                             stripe_nr_end - stripe_nr_orig);
5426                 stripe_nr = div_u64_rem(stripe_nr, map->num_stripes,
5427                                 &stripe_index);
5428                 if (!(rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)))
5429                         mirror_num = 1;
5430         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
5431                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS))
5432                         num_stripes = map->num_stripes;
5433                 else if (mirror_num)
5434                         stripe_index = mirror_num - 1;
5435                 else {
5436                         stripe_index = find_live_mirror(fs_info, map, 0,
5437                                             map->num_stripes,
5438                                             current->pid % map->num_stripes,
5439                                             dev_replace_is_ongoing);
5440                         mirror_num = stripe_index + 1;
5441                 }
5442
5443         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
5444                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) {
5445                         num_stripes = map->num_stripes;
5446                 } else if (mirror_num) {
5447                         stripe_index = mirror_num - 1;
5448                 } else {
5449                         mirror_num = 1;
5450                 }
5451
5452         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
5453                 u32 factor = map->num_stripes / map->sub_stripes;
5454
5455                 stripe_nr = div_u64_rem(stripe_nr, factor, &stripe_index);
5456                 stripe_index *= map->sub_stripes;
5457
5458                 if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS))
5459                         num_stripes = map->sub_stripes;
5460                 else if (rw & REQ_DISCARD)
5461                         num_stripes = min_t(u64, map->sub_stripes *
5462                                             (stripe_nr_end - stripe_nr_orig),
5463                                             map->num_stripes);
5464                 else if (mirror_num)
5465                         stripe_index += mirror_num - 1;
5466                 else {
5467                         int old_stripe_index = stripe_index;
5468                         stripe_index = find_live_mirror(fs_info, map,
5469                                               stripe_index,
5470                                               map->sub_stripes, stripe_index +
5471                                               current->pid % map->sub_stripes,
5472                                               dev_replace_is_ongoing);
5473                         mirror_num = stripe_index - old_stripe_index + 1;
5474                 }
5475
5476         } else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5477                 if (need_raid_map &&
5478                     ((rw & (REQ_WRITE | REQ_GET_READ_MIRRORS)) ||
5479                      mirror_num > 1)) {
5480                         /* push stripe_nr back to the start of the full stripe */
5481                         stripe_nr = div_u64(raid56_full_stripe_start,
5482                                         stripe_len * nr_data_stripes(map));
5483
5484                         /* RAID[56] write or recovery. Return all stripes */
5485                         num_stripes = map->num_stripes;
5486                         max_errors = nr_parity_stripes(map);
5487
5488                         *length = map->stripe_len;
5489                         stripe_index = 0;
5490                         stripe_offset = 0;
5491                 } else {
5492                         /*
5493                          * Mirror #0 or #1 means the original data block.
5494                          * Mirror #2 is RAID5 parity block.
5495                          * Mirror #3 is RAID6 Q block.
5496                          */
5497                         stripe_nr = div_u64_rem(stripe_nr,
5498                                         nr_data_stripes(map), &stripe_index);
5499                         if (mirror_num > 1)
5500                                 stripe_index = nr_data_stripes(map) +
5501                                                 mirror_num - 2;
5502
5503                         /* We distribute the parity blocks across stripes */
5504                         div_u64_rem(stripe_nr + stripe_index, map->num_stripes,
5505                                         &stripe_index);
5506                         if (!(rw & (REQ_WRITE | REQ_DISCARD |
5507                                     REQ_GET_READ_MIRRORS)) && mirror_num <= 1)
5508                                 mirror_num = 1;
5509                 }
5510         } else {
5511                 /*
5512                  * after this, stripe_nr is the number of stripes on this
5513                  * device we have to walk to find the data, and stripe_index is
5514                  * the number of our device in the stripe array
5515                  */
5516                 stripe_nr = div_u64_rem(stripe_nr, map->num_stripes,
5517                                 &stripe_index);
5518                 mirror_num = stripe_index + 1;
5519         }
5520         BUG_ON(stripe_index >= map->num_stripes);
5521
5522         num_alloc_stripes = num_stripes;
5523         if (dev_replace_is_ongoing) {
5524                 if (rw & (REQ_WRITE | REQ_DISCARD))
5525                         num_alloc_stripes <<= 1;
5526                 if (rw & REQ_GET_READ_MIRRORS)
5527                         num_alloc_stripes++;
5528                 tgtdev_indexes = num_stripes;
5529         }
5530
5531         bbio = alloc_btrfs_bio(num_alloc_stripes, tgtdev_indexes);
5532         if (!bbio) {
5533                 ret = -ENOMEM;
5534                 goto out;
5535         }
5536         if (dev_replace_is_ongoing)
5537                 bbio->tgtdev_map = (int *)(bbio->stripes + num_alloc_stripes);
5538
5539         /* build raid_map */
5540         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK &&
5541             need_raid_map && ((rw & (REQ_WRITE | REQ_GET_READ_MIRRORS)) ||
5542             mirror_num > 1)) {
5543                 u64 tmp;
5544                 unsigned rot;
5545
5546                 bbio->raid_map = (u64 *)((void *)bbio->stripes +
5547                                  sizeof(struct btrfs_bio_stripe) *
5548                                  num_alloc_stripes +
5549                                  sizeof(int) * tgtdev_indexes);
5550
5551                 /* Work out the disk rotation on this stripe-set */
5552                 div_u64_rem(stripe_nr, num_stripes, &rot);
5553
5554                 /* Fill in the logical address of each stripe */
5555                 tmp = stripe_nr * nr_data_stripes(map);
5556                 for (i = 0; i < nr_data_stripes(map); i++)
5557                         bbio->raid_map[(i+rot) % num_stripes] =
5558                                 em->start + (tmp + i) * map->stripe_len;
5559
5560                 bbio->raid_map[(i+rot) % map->num_stripes] = RAID5_P_STRIPE;
5561                 if (map->type & BTRFS_BLOCK_GROUP_RAID6)
5562                         bbio->raid_map[(i+rot+1) % num_stripes] =
5563                                 RAID6_Q_STRIPE;
5564         }
5565
5566         if (rw & REQ_DISCARD) {
5567                 u32 factor = 0;
5568                 u32 sub_stripes = 0;
5569                 u64 stripes_per_dev = 0;
5570                 u32 remaining_stripes = 0;
5571                 u32 last_stripe = 0;
5572
5573                 if (map->type &
5574                     (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
5575                         if (map->type & BTRFS_BLOCK_GROUP_RAID0)
5576                                 sub_stripes = 1;
5577                         else
5578                                 sub_stripes = map->sub_stripes;
5579
5580                         factor = map->num_stripes / sub_stripes;
5581                         stripes_per_dev = div_u64_rem(stripe_nr_end -
5582                                                       stripe_nr_orig,
5583                                                       factor,
5584                                                       &remaining_stripes);
5585                         div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
5586                         last_stripe *= sub_stripes;
5587                 }
5588
5589                 for (i = 0; i < num_stripes; i++) {
5590                         bbio->stripes[i].physical =
5591                                 map->stripes[stripe_index].physical +
5592                                 stripe_offset + stripe_nr * map->stripe_len;
5593                         bbio->stripes[i].dev = map->stripes[stripe_index].dev;
5594
5595                         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
5596                                          BTRFS_BLOCK_GROUP_RAID10)) {
5597                                 bbio->stripes[i].length = stripes_per_dev *
5598                                                           map->stripe_len;
5599
5600                                 if (i / sub_stripes < remaining_stripes)
5601                                         bbio->stripes[i].length +=
5602                                                 map->stripe_len;
5603
5604                                 /*
5605                                  * Special for the first stripe and
5606                                  * the last stripe:
5607                                  *
5608                                  * |-------|...|-------|
5609                                  *     |----------|
5610                                  *    off     end_off
5611                                  */
5612                                 if (i < sub_stripes)
5613                                         bbio->stripes[i].length -=
5614                                                 stripe_offset;
5615
5616                                 if (stripe_index >= last_stripe &&
5617                                     stripe_index <= (last_stripe +
5618                                                      sub_stripes - 1))
5619                                         bbio->stripes[i].length -=
5620                                                 stripe_end_offset;
5621
5622                                 if (i == sub_stripes - 1)
5623                                         stripe_offset = 0;
5624                         } else
5625                                 bbio->stripes[i].length = *length;
5626
5627                         stripe_index++;
5628                         if (stripe_index == map->num_stripes) {
5629                                 /* This could only happen for RAID0/10 */
5630                                 stripe_index = 0;
5631                                 stripe_nr++;
5632                         }
5633                 }
5634         } else {
5635                 for (i = 0; i < num_stripes; i++) {
5636                         bbio->stripes[i].physical =
5637                                 map->stripes[stripe_index].physical +
5638                                 stripe_offset +
5639                                 stripe_nr * map->stripe_len;
5640                         bbio->stripes[i].dev =
5641                                 map->stripes[stripe_index].dev;
5642                         stripe_index++;
5643                 }
5644         }
5645
5646         if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS))
5647                 max_errors = btrfs_chunk_max_errors(map);
5648
5649         if (bbio->raid_map)
5650                 sort_parity_stripes(bbio, num_stripes);
5651
5652         tgtdev_indexes = 0;
5653         if (dev_replace_is_ongoing && (rw & (REQ_WRITE | REQ_DISCARD)) &&
5654             dev_replace->tgtdev != NULL) {
5655                 int index_where_to_add;
5656                 u64 srcdev_devid = dev_replace->srcdev->devid;
5657
5658                 /*
5659                  * duplicate the write operations while the dev replace
5660                  * procedure is running. Since the copying of the old disk
5661                  * to the new disk takes place at run time while the
5662                  * filesystem is mounted writable, the regular write
5663                  * operations to the old disk have to be duplicated to go
5664                  * to the new disk as well.
5665                  * Note that device->missing is handled by the caller, and
5666                  * that the write to the old disk is already set up in the
5667                  * stripes array.
5668                  */
5669                 index_where_to_add = num_stripes;
5670                 for (i = 0; i < num_stripes; i++) {
5671                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
5672                                 /* write to new disk, too */
5673                                 struct btrfs_bio_stripe *new =
5674                                         bbio->stripes + index_where_to_add;
5675                                 struct btrfs_bio_stripe *old =
5676                                         bbio->stripes + i;
5677
5678                                 new->physical = old->physical;
5679                                 new->length = old->length;
5680                                 new->dev = dev_replace->tgtdev;
5681                                 bbio->tgtdev_map[i] = index_where_to_add;
5682                                 index_where_to_add++;
5683                                 max_errors++;
5684                                 tgtdev_indexes++;
5685                         }
5686                 }
5687                 num_stripes = index_where_to_add;
5688         } else if (dev_replace_is_ongoing && (rw & REQ_GET_READ_MIRRORS) &&
5689                    dev_replace->tgtdev != NULL) {
5690                 u64 srcdev_devid = dev_replace->srcdev->devid;
5691                 int index_srcdev = 0;
5692                 int found = 0;
5693                 u64 physical_of_found = 0;
5694
5695                 /*
5696                  * During the dev-replace procedure, the target drive can
5697                  * also be used to read data in case it is needed to repair
5698                  * a corrupt block elsewhere. This is possible if the
5699                  * requested area is left of the left cursor. In this area,
5700                  * the target drive is a full copy of the source drive.
5701                  */
5702                 for (i = 0; i < num_stripes; i++) {
5703                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
5704                                 /*
5705                                  * In case of DUP, in order to keep it
5706                                  * simple, only add the mirror with the
5707                                  * lowest physical address
5708                                  */
5709                                 if (found &&
5710                                     physical_of_found <=
5711                                      bbio->stripes[i].physical)
5712                                         continue;
5713                                 index_srcdev = i;
5714                                 found = 1;
5715                                 physical_of_found = bbio->stripes[i].physical;
5716                         }
5717                 }
5718                 if (found) {
5719                         if (physical_of_found + map->stripe_len <=
5720                             dev_replace->cursor_left) {
5721                                 struct btrfs_bio_stripe *tgtdev_stripe =
5722                                         bbio->stripes + num_stripes;
5723
5724                                 tgtdev_stripe->physical = physical_of_found;
5725                                 tgtdev_stripe->length =
5726                                         bbio->stripes[index_srcdev].length;
5727                                 tgtdev_stripe->dev = dev_replace->tgtdev;
5728                                 bbio->tgtdev_map[index_srcdev] = num_stripes;
5729
5730                                 tgtdev_indexes++;
5731                                 num_stripes++;
5732                         }
5733                 }
5734         }
5735
5736         *bbio_ret = bbio;
5737         bbio->map_type = map->type;
5738         bbio->num_stripes = num_stripes;
5739         bbio->max_errors = max_errors;
5740         bbio->mirror_num = mirror_num;
5741         bbio->num_tgtdevs = tgtdev_indexes;
5742
5743         /*
5744          * this is the case that REQ_READ && dev_replace_is_ongoing &&
5745          * mirror_num == num_stripes + 1 && dev_replace target drive is
5746          * available as a mirror
5747          */
5748         if (patch_the_first_stripe_for_dev_replace && num_stripes > 0) {
5749                 WARN_ON(num_stripes > 1);
5750                 bbio->stripes[0].dev = dev_replace->tgtdev;
5751                 bbio->stripes[0].physical = physical_to_patch_in_first_stripe;
5752                 bbio->mirror_num = map->num_stripes + 1;
5753         }
5754 out:
5755         if (dev_replace_is_ongoing)
5756                 btrfs_dev_replace_unlock(dev_replace);
5757         free_extent_map(em);
5758         return ret;
5759 }
5760
5761 int btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
5762                       u64 logical, u64 *length,
5763                       struct btrfs_bio **bbio_ret, int mirror_num)
5764 {
5765         return __btrfs_map_block(fs_info, rw, logical, length, bbio_ret,
5766                                  mirror_num, 0);
5767 }
5768
5769 /* For Scrub/replace */
5770 int btrfs_map_sblock(struct btrfs_fs_info *fs_info, int rw,
5771                      u64 logical, u64 *length,
5772                      struct btrfs_bio **bbio_ret, int mirror_num,
5773                      int need_raid_map)
5774 {
5775         return __btrfs_map_block(fs_info, rw, logical, length, bbio_ret,
5776                                  mirror_num, need_raid_map);
5777 }
5778
5779 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
5780                      u64 chunk_start, u64 physical, u64 devid,
5781                      u64 **logical, int *naddrs, int *stripe_len)
5782 {
5783         struct extent_map_tree *em_tree = &map_tree->map_tree;
5784         struct extent_map *em;
5785         struct map_lookup *map;
5786         u64 *buf;
5787         u64 bytenr;
5788         u64 length;
5789         u64 stripe_nr;
5790         u64 rmap_len;
5791         int i, j, nr = 0;
5792
5793         read_lock(&em_tree->lock);
5794         em = lookup_extent_mapping(em_tree, chunk_start, 1);
5795         read_unlock(&em_tree->lock);
5796
5797         if (!em) {
5798                 printk(KERN_ERR "BTRFS: couldn't find em for chunk %Lu\n",
5799                        chunk_start);
5800                 return -EIO;
5801         }
5802
5803         if (em->start != chunk_start) {
5804                 printk(KERN_ERR "BTRFS: bad chunk start, em=%Lu, wanted=%Lu\n",
5805                        em->start, chunk_start);
5806                 free_extent_map(em);
5807                 return -EIO;
5808         }
5809         map = (struct map_lookup *)em->bdev;
5810
5811         length = em->len;
5812         rmap_len = map->stripe_len;
5813
5814         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
5815                 length = div_u64(length, map->num_stripes / map->sub_stripes);
5816         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
5817                 length = div_u64(length, map->num_stripes);
5818         else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5819                 length = div_u64(length, nr_data_stripes(map));
5820                 rmap_len = map->stripe_len * nr_data_stripes(map);
5821         }
5822
5823         buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS);
5824         BUG_ON(!buf); /* -ENOMEM */
5825
5826         for (i = 0; i < map->num_stripes; i++) {
5827                 if (devid && map->stripes[i].dev->devid != devid)
5828                         continue;
5829                 if (map->stripes[i].physical > physical ||
5830                     map->stripes[i].physical + length <= physical)
5831                         continue;
5832
5833                 stripe_nr = physical - map->stripes[i].physical;
5834                 stripe_nr = div_u64(stripe_nr, map->stripe_len);
5835
5836                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
5837                         stripe_nr = stripe_nr * map->num_stripes + i;
5838                         stripe_nr = div_u64(stripe_nr, map->sub_stripes);
5839                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
5840                         stripe_nr = stripe_nr * map->num_stripes + i;
5841                 } /* else if RAID[56], multiply by nr_data_stripes().
5842                    * Alternatively, just use rmap_len below instead of
5843                    * map->stripe_len */
5844
5845                 bytenr = chunk_start + stripe_nr * rmap_len;
5846                 WARN_ON(nr >= map->num_stripes);
5847                 for (j = 0; j < nr; j++) {
5848                         if (buf[j] == bytenr)
5849                                 break;
5850                 }
5851                 if (j == nr) {
5852                         WARN_ON(nr >= map->num_stripes);
5853                         buf[nr++] = bytenr;
5854                 }
5855         }
5856
5857         *logical = buf;
5858         *naddrs = nr;
5859         *stripe_len = rmap_len;
5860
5861         free_extent_map(em);
5862         return 0;
5863 }
5864
5865 static inline void btrfs_end_bbio(struct btrfs_bio *bbio, struct bio *bio)
5866 {
5867         bio->bi_private = bbio->private;
5868         bio->bi_end_io = bbio->end_io;
5869         bio_endio(bio);
5870
5871         btrfs_put_bbio(bbio);
5872 }
5873
5874 static void btrfs_end_bio(struct bio *bio)
5875 {
5876         struct btrfs_bio *bbio = bio->bi_private;
5877         int is_orig_bio = 0;
5878
5879         if (bio->bi_error) {
5880                 atomic_inc(&bbio->error);
5881                 if (bio->bi_error == -EIO || bio->bi_error == -EREMOTEIO) {
5882                         unsigned int stripe_index =
5883                                 btrfs_io_bio(bio)->stripe_index;
5884                         struct btrfs_device *dev;
5885
5886                         BUG_ON(stripe_index >= bbio->num_stripes);
5887                         dev = bbio->stripes[stripe_index].dev;
5888                         if (dev->bdev) {
5889                                 if (bio->bi_rw & WRITE)
5890                                         btrfs_dev_stat_inc(dev,
5891                                                 BTRFS_DEV_STAT_WRITE_ERRS);
5892                                 else
5893                                         btrfs_dev_stat_inc(dev,
5894                                                 BTRFS_DEV_STAT_READ_ERRS);
5895                                 if ((bio->bi_rw & WRITE_FLUSH) == WRITE_FLUSH)
5896                                         btrfs_dev_stat_inc(dev,
5897                                                 BTRFS_DEV_STAT_FLUSH_ERRS);
5898                                 btrfs_dev_stat_print_on_error(dev);
5899                         }
5900                 }
5901         }
5902
5903         if (bio == bbio->orig_bio)
5904                 is_orig_bio = 1;
5905
5906         btrfs_bio_counter_dec(bbio->fs_info);
5907
5908         if (atomic_dec_and_test(&bbio->stripes_pending)) {
5909                 if (!is_orig_bio) {
5910                         bio_put(bio);
5911                         bio = bbio->orig_bio;
5912                 }
5913
5914                 btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
5915                 /* only send an error to the higher layers if it is
5916                  * beyond the tolerance of the btrfs bio
5917                  */
5918                 if (atomic_read(&bbio->error) > bbio->max_errors) {
5919                         bio->bi_error = -EIO;
5920                 } else {
5921                         /*
5922                          * this bio is actually up to date, we didn't
5923                          * go over the max number of errors
5924                          */
5925                         bio->bi_error = 0;
5926                 }
5927
5928                 btrfs_end_bbio(bbio, bio);
5929         } else if (!is_orig_bio) {
5930                 bio_put(bio);
5931         }
5932 }
5933
5934 /*
5935  * see run_scheduled_bios for a description of why bios are collected for
5936  * async submit.
5937  *
5938  * This will add one bio to the pending list for a device and make sure
5939  * the work struct is scheduled.
5940  */
5941 static noinline void btrfs_schedule_bio(struct btrfs_root *root,
5942                                         struct btrfs_device *device,
5943                                         int rw, struct bio *bio)
5944 {
5945         int should_queue = 1;
5946         struct btrfs_pending_bios *pending_bios;
5947
5948         if (device->missing || !device->bdev) {
5949                 bio_io_error(bio);
5950                 return;
5951         }
5952
5953         /* don't bother with additional async steps for reads, right now */
5954         if (!(rw & REQ_WRITE)) {
5955                 bio_get(bio);
5956                 btrfsic_submit_bio(rw, bio);
5957                 bio_put(bio);
5958                 return;
5959         }
5960
5961         /*
5962          * nr_async_bios allows us to reliably return congestion to the
5963          * higher layers.  Otherwise, the async bio makes it appear we have
5964          * made progress against dirty pages when we've really just put it
5965          * on a queue for later
5966          */
5967         atomic_inc(&root->fs_info->nr_async_bios);
5968         WARN_ON(bio->bi_next);
5969         bio->bi_next = NULL;
5970         bio->bi_rw |= rw;
5971
5972         spin_lock(&device->io_lock);
5973         if (bio->bi_rw & REQ_SYNC)
5974                 pending_bios = &device->pending_sync_bios;
5975         else
5976                 pending_bios = &device->pending_bios;
5977
5978         if (pending_bios->tail)
5979                 pending_bios->tail->bi_next = bio;
5980
5981         pending_bios->tail = bio;
5982         if (!pending_bios->head)
5983                 pending_bios->head = bio;
5984         if (device->running_pending)
5985                 should_queue = 0;
5986
5987         spin_unlock(&device->io_lock);
5988
5989         if (should_queue)
5990                 btrfs_queue_work(root->fs_info->submit_workers,
5991                                  &device->work);
5992 }
5993
5994 static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
5995                               struct bio *bio, u64 physical, int dev_nr,
5996                               int rw, int async)
5997 {
5998         struct btrfs_device *dev = bbio->stripes[dev_nr].dev;
5999
6000         bio->bi_private = bbio;
6001         btrfs_io_bio(bio)->stripe_index = dev_nr;
6002         bio->bi_end_io = btrfs_end_bio;
6003         bio->bi_iter.bi_sector = physical >> 9;
6004 #ifdef DEBUG
6005         {
6006                 struct rcu_string *name;
6007
6008                 rcu_read_lock();
6009                 name = rcu_dereference(dev->name);
6010                 pr_debug("btrfs_map_bio: rw %d, sector=%llu, dev=%lu "
6011                          "(%s id %llu), size=%u\n", rw,
6012                          (u64)bio->bi_iter.bi_sector, (u_long)dev->bdev->bd_dev,
6013                          name->str, dev->devid, bio->bi_iter.bi_size);
6014                 rcu_read_unlock();
6015         }
6016 #endif
6017         bio->bi_bdev = dev->bdev;
6018
6019         btrfs_bio_counter_inc_noblocked(root->fs_info);
6020
6021         if (async)
6022                 btrfs_schedule_bio(root, dev, rw, bio);
6023         else
6024                 btrfsic_submit_bio(rw, bio);
6025 }
6026
6027 static void bbio_error(struct btrfs_bio *bbio, struct bio *bio, u64 logical)
6028 {
6029         atomic_inc(&bbio->error);
6030         if (atomic_dec_and_test(&bbio->stripes_pending)) {
6031                 /* Shoud be the original bio. */
6032                 WARN_ON(bio != bbio->orig_bio);
6033
6034                 btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
6035                 bio->bi_iter.bi_sector = logical >> 9;
6036                 bio->bi_error = -EIO;
6037                 btrfs_end_bbio(bbio, bio);
6038         }
6039 }
6040
6041 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
6042                   int mirror_num, int async_submit)
6043 {
6044         struct btrfs_device *dev;
6045         struct bio *first_bio = bio;
6046         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
6047         u64 length = 0;
6048         u64 map_length;
6049         int ret;
6050         int dev_nr;
6051         int total_devs;
6052         struct btrfs_bio *bbio = NULL;
6053
6054         length = bio->bi_iter.bi_size;
6055         map_length = length;
6056
6057         btrfs_bio_counter_inc_blocked(root->fs_info);
6058         ret = __btrfs_map_block(root->fs_info, rw, logical, &map_length, &bbio,
6059                               mirror_num, 1);
6060         if (ret) {
6061                 btrfs_bio_counter_dec(root->fs_info);
6062                 return ret;
6063         }
6064
6065         total_devs = bbio->num_stripes;
6066         bbio->orig_bio = first_bio;
6067         bbio->private = first_bio->bi_private;
6068         bbio->end_io = first_bio->bi_end_io;
6069         bbio->fs_info = root->fs_info;
6070         atomic_set(&bbio->stripes_pending, bbio->num_stripes);
6071
6072         if (bbio->raid_map) {
6073                 /* In this case, map_length has been set to the length of
6074                    a single stripe; not the whole write */
6075                 if (rw & WRITE) {
6076                         ret = raid56_parity_write(root, bio, bbio, map_length);
6077                 } else {
6078                         ret = raid56_parity_recover(root, bio, bbio, map_length,
6079                                                     mirror_num, 1);
6080                 }
6081
6082                 btrfs_bio_counter_dec(root->fs_info);
6083                 return ret;
6084         }
6085
6086         if (map_length < length) {
6087                 btrfs_crit(root->fs_info, "mapping failed logical %llu bio len %llu len %llu",
6088                         logical, length, map_length);
6089                 BUG();
6090         }
6091
6092         for (dev_nr = 0; dev_nr < total_devs; dev_nr++) {
6093                 dev = bbio->stripes[dev_nr].dev;
6094                 if (!dev || !dev->bdev || (rw & WRITE && !dev->writeable)) {
6095                         bbio_error(bbio, first_bio, logical);
6096                         continue;
6097                 }
6098
6099                 if (dev_nr < total_devs - 1) {
6100                         bio = btrfs_bio_clone(first_bio, GFP_NOFS);
6101                         BUG_ON(!bio); /* -ENOMEM */
6102                 } else
6103                         bio = first_bio;
6104
6105                 submit_stripe_bio(root, bbio, bio,
6106                                   bbio->stripes[dev_nr].physical, dev_nr, rw,
6107                                   async_submit);
6108         }
6109         btrfs_bio_counter_dec(root->fs_info);
6110         return 0;
6111 }
6112
6113 struct btrfs_device *btrfs_find_device(struct btrfs_fs_info *fs_info, u64 devid,
6114                                        u8 *uuid, u8 *fsid)
6115 {
6116         struct btrfs_device *device;
6117         struct btrfs_fs_devices *cur_devices;
6118
6119         cur_devices = fs_info->fs_devices;
6120         while (cur_devices) {
6121                 if (!fsid ||
6122                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
6123                         device = __find_device(&cur_devices->devices,
6124                                                devid, uuid);
6125                         if (device)
6126                                 return device;
6127                 }
6128                 cur_devices = cur_devices->seed;
6129         }
6130         return NULL;
6131 }
6132
6133 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
6134                                             struct btrfs_fs_devices *fs_devices,
6135                                             u64 devid, u8 *dev_uuid)
6136 {
6137         struct btrfs_device *device;
6138
6139         device = btrfs_alloc_device(NULL, &devid, dev_uuid);
6140         if (IS_ERR(device))
6141                 return NULL;
6142
6143         list_add(&device->dev_list, &fs_devices->devices);
6144         device->fs_devices = fs_devices;
6145         fs_devices->num_devices++;
6146
6147         device->missing = 1;
6148         fs_devices->missing_devices++;
6149
6150         return device;
6151 }
6152
6153 /**
6154  * btrfs_alloc_device - allocate struct btrfs_device
6155  * @fs_info:    used only for generating a new devid, can be NULL if
6156  *              devid is provided (i.e. @devid != NULL).
6157  * @devid:      a pointer to devid for this device.  If NULL a new devid
6158  *              is generated.
6159  * @uuid:       a pointer to UUID for this device.  If NULL a new UUID
6160  *              is generated.
6161  *
6162  * Return: a pointer to a new &struct btrfs_device on success; ERR_PTR()
6163  * on error.  Returned struct is not linked onto any lists and can be
6164  * destroyed with kfree() right away.
6165  */
6166 struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info,
6167                                         const u64 *devid,
6168                                         const u8 *uuid)
6169 {
6170         struct btrfs_device *dev;
6171         u64 tmp;
6172
6173         if (WARN_ON(!devid && !fs_info))
6174                 return ERR_PTR(-EINVAL);
6175
6176         dev = __alloc_device();
6177         if (IS_ERR(dev))
6178                 return dev;
6179
6180         if (devid)
6181                 tmp = *devid;
6182         else {
6183                 int ret;
6184
6185                 ret = find_next_devid(fs_info, &tmp);
6186                 if (ret) {
6187                         kfree(dev);
6188                         return ERR_PTR(ret);
6189                 }
6190         }
6191         dev->devid = tmp;
6192
6193         if (uuid)
6194                 memcpy(dev->uuid, uuid, BTRFS_UUID_SIZE);
6195         else
6196                 generate_random_uuid(dev->uuid);
6197
6198         btrfs_init_work(&dev->work, btrfs_submit_helper,
6199                         pending_bios_fn, NULL, NULL);
6200
6201         return dev;
6202 }
6203
6204 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
6205                           struct extent_buffer *leaf,
6206                           struct btrfs_chunk *chunk)
6207 {
6208         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
6209         struct map_lookup *map;
6210         struct extent_map *em;
6211         u64 logical;
6212         u64 length;
6213         u64 devid;
6214         u8 uuid[BTRFS_UUID_SIZE];
6215         int num_stripes;
6216         int ret;
6217         int i;
6218
6219         logical = key->offset;
6220         length = btrfs_chunk_length(leaf, chunk);
6221
6222         read_lock(&map_tree->map_tree.lock);
6223         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
6224         read_unlock(&map_tree->map_tree.lock);
6225
6226         /* already mapped? */
6227         if (em && em->start <= logical && em->start + em->len > logical) {
6228                 free_extent_map(em);
6229                 return 0;
6230         } else if (em) {
6231                 free_extent_map(em);
6232         }
6233
6234         em = alloc_extent_map();
6235         if (!em)
6236                 return -ENOMEM;
6237         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
6238         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
6239         if (!map) {
6240                 free_extent_map(em);
6241                 return -ENOMEM;
6242         }
6243
6244         set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
6245         em->bdev = (struct block_device *)map;
6246         em->start = logical;
6247         em->len = length;
6248         em->orig_start = 0;
6249         em->block_start = 0;
6250         em->block_len = em->len;
6251
6252         map->num_stripes = num_stripes;
6253         map->io_width = btrfs_chunk_io_width(leaf, chunk);
6254         map->io_align = btrfs_chunk_io_align(leaf, chunk);
6255         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
6256         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
6257         map->type = btrfs_chunk_type(leaf, chunk);
6258         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
6259         for (i = 0; i < num_stripes; i++) {
6260                 map->stripes[i].physical =
6261                         btrfs_stripe_offset_nr(leaf, chunk, i);
6262                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
6263                 read_extent_buffer(leaf, uuid, (unsigned long)
6264                                    btrfs_stripe_dev_uuid_nr(chunk, i),
6265                                    BTRFS_UUID_SIZE);
6266                 map->stripes[i].dev = btrfs_find_device(root->fs_info, devid,
6267                                                         uuid, NULL);
6268                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
6269                         free_extent_map(em);
6270                         return -EIO;
6271                 }
6272                 if (!map->stripes[i].dev) {
6273                         map->stripes[i].dev =
6274                                 add_missing_dev(root, root->fs_info->fs_devices,
6275                                                 devid, uuid);
6276                         if (!map->stripes[i].dev) {
6277                                 free_extent_map(em);
6278                                 return -EIO;
6279                         }
6280                         btrfs_warn(root->fs_info, "devid %llu uuid %pU is missing",
6281                                                 devid, uuid);
6282                 }
6283                 map->stripes[i].dev->in_fs_metadata = 1;
6284         }
6285
6286         write_lock(&map_tree->map_tree.lock);
6287         ret = add_extent_mapping(&map_tree->map_tree, em, 0);
6288         write_unlock(&map_tree->map_tree.lock);
6289         BUG_ON(ret); /* Tree corruption */
6290         free_extent_map(em);
6291
6292         return 0;
6293 }
6294
6295 static void fill_device_from_item(struct extent_buffer *leaf,
6296                                  struct btrfs_dev_item *dev_item,
6297                                  struct btrfs_device *device)
6298 {
6299         unsigned long ptr;
6300
6301         device->devid = btrfs_device_id(leaf, dev_item);
6302         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
6303         device->total_bytes = device->disk_total_bytes;
6304         device->commit_total_bytes = device->disk_total_bytes;
6305         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
6306         device->commit_bytes_used = device->bytes_used;
6307         device->type = btrfs_device_type(leaf, dev_item);
6308         device->io_align = btrfs_device_io_align(leaf, dev_item);
6309         device->io_width = btrfs_device_io_width(leaf, dev_item);
6310         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
6311         WARN_ON(device->devid == BTRFS_DEV_REPLACE_DEVID);
6312         device->is_tgtdev_for_dev_replace = 0;
6313
6314         ptr = btrfs_device_uuid(dev_item);
6315         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
6316 }
6317
6318 static struct btrfs_fs_devices *open_seed_devices(struct btrfs_root *root,
6319                                                   u8 *fsid)
6320 {
6321         struct btrfs_fs_devices *fs_devices;
6322         int ret;
6323
6324         BUG_ON(!mutex_is_locked(&uuid_mutex));
6325
6326         fs_devices = root->fs_info->fs_devices->seed;
6327         while (fs_devices) {
6328                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE))
6329                         return fs_devices;
6330
6331                 fs_devices = fs_devices->seed;
6332         }
6333
6334         fs_devices = find_fsid(fsid);
6335         if (!fs_devices) {
6336                 if (!btrfs_test_opt(root, DEGRADED))
6337                         return ERR_PTR(-ENOENT);
6338
6339                 fs_devices = alloc_fs_devices(fsid);
6340                 if (IS_ERR(fs_devices))
6341                         return fs_devices;
6342
6343                 fs_devices->seeding = 1;
6344                 fs_devices->opened = 1;
6345                 return fs_devices;
6346         }
6347
6348         fs_devices = clone_fs_devices(fs_devices);
6349         if (IS_ERR(fs_devices))
6350                 return fs_devices;
6351
6352         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
6353                                    root->fs_info->bdev_holder);
6354         if (ret) {
6355                 free_fs_devices(fs_devices);
6356                 fs_devices = ERR_PTR(ret);
6357                 goto out;
6358         }
6359
6360         if (!fs_devices->seeding) {
6361                 __btrfs_close_devices(fs_devices);
6362                 free_fs_devices(fs_devices);
6363                 fs_devices = ERR_PTR(-EINVAL);
6364                 goto out;
6365         }
6366
6367         fs_devices->seed = root->fs_info->fs_devices->seed;
6368         root->fs_info->fs_devices->seed = fs_devices;
6369 out:
6370         return fs_devices;
6371 }
6372
6373 static int read_one_dev(struct btrfs_root *root,
6374                         struct extent_buffer *leaf,
6375                         struct btrfs_dev_item *dev_item)
6376 {
6377         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
6378         struct btrfs_device *device;
6379         u64 devid;
6380         int ret;
6381         u8 fs_uuid[BTRFS_UUID_SIZE];
6382         u8 dev_uuid[BTRFS_UUID_SIZE];
6383
6384         devid = btrfs_device_id(leaf, dev_item);
6385         read_extent_buffer(leaf, dev_uuid, btrfs_device_uuid(dev_item),
6386                            BTRFS_UUID_SIZE);
6387         read_extent_buffer(leaf, fs_uuid, btrfs_device_fsid(dev_item),
6388                            BTRFS_UUID_SIZE);
6389
6390         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
6391                 fs_devices = open_seed_devices(root, fs_uuid);
6392                 if (IS_ERR(fs_devices))
6393                         return PTR_ERR(fs_devices);
6394         }
6395
6396         device = btrfs_find_device(root->fs_info, devid, dev_uuid, fs_uuid);
6397         if (!device) {
6398                 if (!btrfs_test_opt(root, DEGRADED))
6399                         return -EIO;
6400
6401                 device = add_missing_dev(root, fs_devices, devid, dev_uuid);
6402                 if (!device)
6403                         return -ENOMEM;
6404                 btrfs_warn(root->fs_info, "devid %llu uuid %pU missing",
6405                                 devid, dev_uuid);
6406         } else {
6407                 if (!device->bdev && !btrfs_test_opt(root, DEGRADED))
6408                         return -EIO;
6409
6410                 if(!device->bdev && !device->missing) {
6411                         /*
6412                          * this happens when a device that was properly setup
6413                          * in the device info lists suddenly goes bad.
6414                          * device->bdev is NULL, and so we have to set
6415                          * device->missing to one here
6416                          */
6417                         device->fs_devices->missing_devices++;
6418                         device->missing = 1;
6419                 }
6420
6421                 /* Move the device to its own fs_devices */
6422                 if (device->fs_devices != fs_devices) {
6423                         ASSERT(device->missing);
6424
6425                         list_move(&device->dev_list, &fs_devices->devices);
6426                         device->fs_devices->num_devices--;
6427                         fs_devices->num_devices++;
6428
6429                         device->fs_devices->missing_devices--;
6430                         fs_devices->missing_devices++;
6431
6432                         device->fs_devices = fs_devices;
6433                 }
6434         }
6435
6436         if (device->fs_devices != root->fs_info->fs_devices) {
6437                 BUG_ON(device->writeable);
6438                 if (device->generation !=
6439                     btrfs_device_generation(leaf, dev_item))
6440                         return -EINVAL;
6441         }
6442
6443         fill_device_from_item(leaf, dev_item, device);
6444         device->in_fs_metadata = 1;
6445         if (device->writeable && !device->is_tgtdev_for_dev_replace) {
6446                 device->fs_devices->total_rw_bytes += device->total_bytes;
6447                 spin_lock(&root->fs_info->free_chunk_lock);
6448                 root->fs_info->free_chunk_space += device->total_bytes -
6449                         device->bytes_used;
6450                 spin_unlock(&root->fs_info->free_chunk_lock);
6451         }
6452         ret = 0;
6453         return ret;
6454 }
6455
6456 int btrfs_read_sys_array(struct btrfs_root *root)
6457 {
6458         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
6459         struct extent_buffer *sb;
6460         struct btrfs_disk_key *disk_key;
6461         struct btrfs_chunk *chunk;
6462         u8 *array_ptr;
6463         unsigned long sb_array_offset;
6464         int ret = 0;
6465         u32 num_stripes;
6466         u32 array_size;
6467         u32 len = 0;
6468         u32 cur_offset;
6469         struct btrfs_key key;
6470
6471         ASSERT(BTRFS_SUPER_INFO_SIZE <= root->nodesize);
6472         /*
6473          * This will create extent buffer of nodesize, superblock size is
6474          * fixed to BTRFS_SUPER_INFO_SIZE. If nodesize > sb size, this will
6475          * overallocate but we can keep it as-is, only the first page is used.
6476          */
6477         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET);
6478         if (!sb)
6479                 return -ENOMEM;
6480         set_extent_buffer_uptodate(sb);
6481         btrfs_set_buffer_lockdep_class(root->root_key.objectid, sb, 0);
6482         /*
6483          * The sb extent buffer is artifical and just used to read the system array.
6484          * set_extent_buffer_uptodate() call does not properly mark all it's
6485          * pages up-to-date when the page is larger: extent does not cover the
6486          * whole page and consequently check_page_uptodate does not find all
6487          * the page's extents up-to-date (the hole beyond sb),
6488          * write_extent_buffer then triggers a WARN_ON.
6489          *
6490          * Regular short extents go through mark_extent_buffer_dirty/writeback cycle,
6491          * but sb spans only this function. Add an explicit SetPageUptodate call
6492          * to silence the warning eg. on PowerPC 64.
6493          */
6494         if (PAGE_CACHE_SIZE > BTRFS_SUPER_INFO_SIZE)
6495                 SetPageUptodate(sb->pages[0]);
6496
6497         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
6498         array_size = btrfs_super_sys_array_size(super_copy);
6499
6500         array_ptr = super_copy->sys_chunk_array;
6501         sb_array_offset = offsetof(struct btrfs_super_block, sys_chunk_array);
6502         cur_offset = 0;
6503
6504         while (cur_offset < array_size) {
6505                 disk_key = (struct btrfs_disk_key *)array_ptr;
6506                 len = sizeof(*disk_key);
6507                 if (cur_offset + len > array_size)
6508                         goto out_short_read;
6509
6510                 btrfs_disk_key_to_cpu(&key, disk_key);
6511
6512                 array_ptr += len;
6513                 sb_array_offset += len;
6514                 cur_offset += len;
6515
6516                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
6517                         chunk = (struct btrfs_chunk *)sb_array_offset;
6518                         /*
6519                          * At least one btrfs_chunk with one stripe must be
6520                          * present, exact stripe count check comes afterwards
6521                          */
6522                         len = btrfs_chunk_item_size(1);
6523                         if (cur_offset + len > array_size)
6524                                 goto out_short_read;
6525
6526                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
6527                         if (!num_stripes) {
6528                                 printk(KERN_ERR
6529             "BTRFS: invalid number of stripes %u in sys_array at offset %u\n",
6530                                         num_stripes, cur_offset);
6531                                 ret = -EIO;
6532                                 break;
6533                         }
6534
6535                         len = btrfs_chunk_item_size(num_stripes);
6536                         if (cur_offset + len > array_size)
6537                                 goto out_short_read;
6538
6539                         ret = read_one_chunk(root, &key, sb, chunk);
6540                         if (ret)
6541                                 break;
6542                 } else {
6543                         printk(KERN_ERR
6544                 "BTRFS: unexpected item type %u in sys_array at offset %u\n",
6545                                 (u32)key.type, cur_offset);
6546                         ret = -EIO;
6547                         break;
6548                 }
6549                 array_ptr += len;
6550                 sb_array_offset += len;
6551                 cur_offset += len;
6552         }
6553         free_extent_buffer(sb);
6554         return ret;
6555
6556 out_short_read:
6557         printk(KERN_ERR "BTRFS: sys_array too short to read %u bytes at offset %u\n",
6558                         len, cur_offset);
6559         free_extent_buffer(sb);
6560         return -EIO;
6561 }
6562
6563 int btrfs_read_chunk_tree(struct btrfs_root *root)
6564 {
6565         struct btrfs_path *path;
6566         struct extent_buffer *leaf;
6567         struct btrfs_key key;
6568         struct btrfs_key found_key;
6569         int ret;
6570         int slot;
6571
6572         root = root->fs_info->chunk_root;
6573
6574         path = btrfs_alloc_path();
6575         if (!path)
6576                 return -ENOMEM;
6577
6578         mutex_lock(&uuid_mutex);
6579         lock_chunks(root);
6580
6581         /*
6582          * Read all device items, and then all the chunk items. All
6583          * device items are found before any chunk item (their object id
6584          * is smaller than the lowest possible object id for a chunk
6585          * item - BTRFS_FIRST_CHUNK_TREE_OBJECTID).
6586          */
6587         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
6588         key.offset = 0;
6589         key.type = 0;
6590         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6591         if (ret < 0)
6592                 goto error;
6593         while (1) {
6594                 leaf = path->nodes[0];
6595                 slot = path->slots[0];
6596                 if (slot >= btrfs_header_nritems(leaf)) {
6597                         ret = btrfs_next_leaf(root, path);
6598                         if (ret == 0)
6599                                 continue;
6600                         if (ret < 0)
6601                                 goto error;
6602                         break;
6603                 }
6604                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
6605                 if (found_key.type == BTRFS_DEV_ITEM_KEY) {
6606                         struct btrfs_dev_item *dev_item;
6607                         dev_item = btrfs_item_ptr(leaf, slot,
6608                                                   struct btrfs_dev_item);
6609                         ret = read_one_dev(root, leaf, dev_item);
6610                         if (ret)
6611                                 goto error;
6612                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
6613                         struct btrfs_chunk *chunk;
6614                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
6615                         ret = read_one_chunk(root, &found_key, leaf, chunk);
6616                         if (ret)
6617                                 goto error;
6618                 }
6619                 path->slots[0]++;
6620         }
6621         ret = 0;
6622 error:
6623         unlock_chunks(root);
6624         mutex_unlock(&uuid_mutex);
6625
6626         btrfs_free_path(path);
6627         return ret;
6628 }
6629
6630 void btrfs_init_devices_late(struct btrfs_fs_info *fs_info)
6631 {
6632         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6633         struct btrfs_device *device;
6634
6635         while (fs_devices) {
6636                 mutex_lock(&fs_devices->device_list_mutex);
6637                 list_for_each_entry(device, &fs_devices->devices, dev_list)
6638                         device->dev_root = fs_info->dev_root;
6639                 mutex_unlock(&fs_devices->device_list_mutex);
6640
6641                 fs_devices = fs_devices->seed;
6642         }
6643 }
6644
6645 static void __btrfs_reset_dev_stats(struct btrfs_device *dev)
6646 {
6647         int i;
6648
6649         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6650                 btrfs_dev_stat_reset(dev, i);
6651 }
6652
6653 int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info)
6654 {
6655         struct btrfs_key key;
6656         struct btrfs_key found_key;
6657         struct btrfs_root *dev_root = fs_info->dev_root;
6658         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6659         struct extent_buffer *eb;
6660         int slot;
6661         int ret = 0;
6662         struct btrfs_device *device;
6663         struct btrfs_path *path = NULL;
6664         int i;
6665
6666         path = btrfs_alloc_path();
6667         if (!path) {
6668                 ret = -ENOMEM;
6669                 goto out;
6670         }
6671
6672         mutex_lock(&fs_devices->device_list_mutex);
6673         list_for_each_entry(device, &fs_devices->devices, dev_list) {
6674                 int item_size;
6675                 struct btrfs_dev_stats_item *ptr;
6676
6677                 key.objectid = 0;
6678                 key.type = BTRFS_DEV_STATS_KEY;
6679                 key.offset = device->devid;
6680                 ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
6681                 if (ret) {
6682                         __btrfs_reset_dev_stats(device);
6683                         device->dev_stats_valid = 1;
6684                         btrfs_release_path(path);
6685                         continue;
6686                 }
6687                 slot = path->slots[0];
6688                 eb = path->nodes[0];
6689                 btrfs_item_key_to_cpu(eb, &found_key, slot);
6690                 item_size = btrfs_item_size_nr(eb, slot);
6691
6692                 ptr = btrfs_item_ptr(eb, slot,
6693                                      struct btrfs_dev_stats_item);
6694
6695                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
6696                         if (item_size >= (1 + i) * sizeof(__le64))
6697                                 btrfs_dev_stat_set(device, i,
6698                                         btrfs_dev_stats_value(eb, ptr, i));
6699                         else
6700                                 btrfs_dev_stat_reset(device, i);
6701                 }
6702
6703                 device->dev_stats_valid = 1;
6704                 btrfs_dev_stat_print_on_load(device);
6705                 btrfs_release_path(path);
6706         }
6707         mutex_unlock(&fs_devices->device_list_mutex);
6708
6709 out:
6710         btrfs_free_path(path);
6711         return ret < 0 ? ret : 0;
6712 }
6713
6714 static int update_dev_stat_item(struct btrfs_trans_handle *trans,
6715                                 struct btrfs_root *dev_root,
6716                                 struct btrfs_device *device)
6717 {
6718         struct btrfs_path *path;
6719         struct btrfs_key key;
6720         struct extent_buffer *eb;
6721         struct btrfs_dev_stats_item *ptr;
6722         int ret;
6723         int i;
6724
6725         key.objectid = 0;
6726         key.type = BTRFS_DEV_STATS_KEY;
6727         key.offset = device->devid;
6728
6729         path = btrfs_alloc_path();
6730         BUG_ON(!path);
6731         ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
6732         if (ret < 0) {
6733                 btrfs_warn_in_rcu(dev_root->fs_info,
6734                         "error %d while searching for dev_stats item for device %s",
6735                               ret, rcu_str_deref(device->name));
6736                 goto out;
6737         }
6738
6739         if (ret == 0 &&
6740             btrfs_item_size_nr(path->nodes[0], path->slots[0]) < sizeof(*ptr)) {
6741                 /* need to delete old one and insert a new one */
6742                 ret = btrfs_del_item(trans, dev_root, path);
6743                 if (ret != 0) {
6744                         btrfs_warn_in_rcu(dev_root->fs_info,
6745                                 "delete too small dev_stats item for device %s failed %d",
6746                                       rcu_str_deref(device->name), ret);
6747                         goto out;
6748                 }
6749                 ret = 1;
6750         }
6751
6752         if (ret == 1) {
6753                 /* need to insert a new item */
6754                 btrfs_release_path(path);
6755                 ret = btrfs_insert_empty_item(trans, dev_root, path,
6756                                               &key, sizeof(*ptr));
6757                 if (ret < 0) {
6758                         btrfs_warn_in_rcu(dev_root->fs_info,
6759                                 "insert dev_stats item for device %s failed %d",
6760                                 rcu_str_deref(device->name), ret);
6761                         goto out;
6762                 }
6763         }
6764
6765         eb = path->nodes[0];
6766         ptr = btrfs_item_ptr(eb, path->slots[0], struct btrfs_dev_stats_item);
6767         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6768                 btrfs_set_dev_stats_value(eb, ptr, i,
6769                                           btrfs_dev_stat_read(device, i));
6770         btrfs_mark_buffer_dirty(eb);
6771
6772 out:
6773         btrfs_free_path(path);
6774         return ret;
6775 }
6776
6777 /*
6778  * called from commit_transaction. Writes all changed device stats to disk.
6779  */
6780 int btrfs_run_dev_stats(struct btrfs_trans_handle *trans,
6781                         struct btrfs_fs_info *fs_info)
6782 {
6783         struct btrfs_root *dev_root = fs_info->dev_root;
6784         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6785         struct btrfs_device *device;
6786         int stats_cnt;
6787         int ret = 0;
6788
6789         mutex_lock(&fs_devices->device_list_mutex);
6790         list_for_each_entry(device, &fs_devices->devices, dev_list) {
6791                 if (!device->dev_stats_valid || !btrfs_dev_stats_dirty(device))
6792                         continue;
6793
6794                 stats_cnt = atomic_read(&device->dev_stats_ccnt);
6795                 ret = update_dev_stat_item(trans, dev_root, device);
6796                 if (!ret)
6797                         atomic_sub(stats_cnt, &device->dev_stats_ccnt);
6798         }
6799         mutex_unlock(&fs_devices->device_list_mutex);
6800
6801         return ret;
6802 }
6803
6804 void btrfs_dev_stat_inc_and_print(struct btrfs_device *dev, int index)
6805 {
6806         btrfs_dev_stat_inc(dev, index);
6807         btrfs_dev_stat_print_on_error(dev);
6808 }
6809
6810 static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev)
6811 {
6812         if (!dev->dev_stats_valid)
6813                 return;
6814         btrfs_err_rl_in_rcu(dev->dev_root->fs_info,
6815                 "bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u",
6816                            rcu_str_deref(dev->name),
6817                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
6818                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
6819                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
6820                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
6821                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
6822 }
6823
6824 static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
6825 {
6826         int i;
6827
6828         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6829                 if (btrfs_dev_stat_read(dev, i) != 0)
6830                         break;
6831         if (i == BTRFS_DEV_STAT_VALUES_MAX)
6832                 return; /* all values == 0, suppress message */
6833
6834         btrfs_info_in_rcu(dev->dev_root->fs_info,
6835                 "bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u",
6836                rcu_str_deref(dev->name),
6837                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
6838                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
6839                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
6840                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
6841                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
6842 }
6843
6844 int btrfs_get_dev_stats(struct btrfs_root *root,
6845                         struct btrfs_ioctl_get_dev_stats *stats)
6846 {
6847         struct btrfs_device *dev;
6848         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
6849         int i;
6850
6851         mutex_lock(&fs_devices->device_list_mutex);
6852         dev = btrfs_find_device(root->fs_info, stats->devid, NULL, NULL);
6853         mutex_unlock(&fs_devices->device_list_mutex);
6854
6855         if (!dev) {
6856                 btrfs_warn(root->fs_info, "get dev_stats failed, device not found");
6857                 return -ENODEV;
6858         } else if (!dev->dev_stats_valid) {
6859                 btrfs_warn(root->fs_info, "get dev_stats failed, not yet valid");
6860                 return -ENODEV;
6861         } else if (stats->flags & BTRFS_DEV_STATS_RESET) {
6862                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
6863                         if (stats->nr_items > i)
6864                                 stats->values[i] =
6865                                         btrfs_dev_stat_read_and_reset(dev, i);
6866                         else
6867                                 btrfs_dev_stat_reset(dev, i);
6868                 }
6869         } else {
6870                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6871                         if (stats->nr_items > i)
6872                                 stats->values[i] = btrfs_dev_stat_read(dev, i);
6873         }
6874         if (stats->nr_items > BTRFS_DEV_STAT_VALUES_MAX)
6875                 stats->nr_items = BTRFS_DEV_STAT_VALUES_MAX;
6876         return 0;
6877 }
6878
6879 void btrfs_scratch_superblocks(struct block_device *bdev, char *device_path)
6880 {
6881         struct buffer_head *bh;
6882         struct btrfs_super_block *disk_super;
6883         int copy_num;
6884
6885         if (!bdev)
6886                 return;
6887
6888         for (copy_num = 0; copy_num < BTRFS_SUPER_MIRROR_MAX;
6889                 copy_num++) {
6890
6891                 if (btrfs_read_dev_one_super(bdev, copy_num, &bh))
6892                         continue;
6893
6894                 disk_super = (struct btrfs_super_block *)bh->b_data;
6895
6896                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
6897                 set_buffer_dirty(bh);
6898                 sync_dirty_buffer(bh);
6899                 brelse(bh);
6900         }
6901
6902         /* Notify udev that device has changed */
6903         btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
6904
6905         /* Update ctime/mtime for device path for libblkid */
6906         update_dev_time(device_path);
6907 }
6908
6909 /*
6910  * Update the size of all devices, which is used for writing out the
6911  * super blocks.
6912  */
6913 void btrfs_update_commit_device_size(struct btrfs_fs_info *fs_info)
6914 {
6915         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6916         struct btrfs_device *curr, *next;
6917
6918         if (list_empty(&fs_devices->resized_devices))
6919                 return;
6920
6921         mutex_lock(&fs_devices->device_list_mutex);
6922         lock_chunks(fs_info->dev_root);
6923         list_for_each_entry_safe(curr, next, &fs_devices->resized_devices,
6924                                  resized_list) {
6925                 list_del_init(&curr->resized_list);
6926                 curr->commit_total_bytes = curr->disk_total_bytes;
6927         }
6928         unlock_chunks(fs_info->dev_root);
6929         mutex_unlock(&fs_devices->device_list_mutex);
6930 }
6931
6932 /* Must be invoked during the transaction commit */
6933 void btrfs_update_commit_device_bytes_used(struct btrfs_root *root,
6934                                         struct btrfs_transaction *transaction)
6935 {
6936         struct extent_map *em;
6937         struct map_lookup *map;
6938         struct btrfs_device *dev;
6939         int i;
6940
6941         if (list_empty(&transaction->pending_chunks))
6942                 return;
6943
6944         /* In order to kick the device replace finish process */
6945         lock_chunks(root);
6946         list_for_each_entry(em, &transaction->pending_chunks, list) {
6947                 map = (struct map_lookup *)em->bdev;
6948
6949                 for (i = 0; i < map->num_stripes; i++) {
6950                         dev = map->stripes[i].dev;
6951                         dev->commit_bytes_used = dev->bytes_used;
6952                 }
6953         }
6954         unlock_chunks(root);
6955 }
6956
6957 void btrfs_set_fs_info_ptr(struct btrfs_fs_info *fs_info)
6958 {
6959         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6960         while (fs_devices) {
6961                 fs_devices->fs_info = fs_info;
6962                 fs_devices = fs_devices->seed;
6963         }
6964 }
6965
6966 void btrfs_reset_fs_info_ptr(struct btrfs_fs_info *fs_info)
6967 {
6968         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6969         while (fs_devices) {
6970                 fs_devices->fs_info = NULL;
6971                 fs_devices = fs_devices->seed;
6972         }
6973 }
6974
6975 static void btrfs_close_one_device(struct btrfs_device *device)
6976 {
6977         struct btrfs_fs_devices *fs_devices = device->fs_devices;
6978         struct btrfs_device *new_device;
6979         struct rcu_string *name;
6980
6981         if (device->bdev)
6982                 fs_devices->open_devices--;
6983
6984         if (device->writeable &&
6985             device->devid != BTRFS_DEV_REPLACE_DEVID) {
6986                 list_del_init(&device->dev_alloc_list);
6987                 fs_devices->rw_devices--;
6988         }
6989
6990         if (device->missing)
6991                 fs_devices->missing_devices--;
6992
6993         new_device = btrfs_alloc_device(NULL, &device->devid,
6994                                         device->uuid);
6995         BUG_ON(IS_ERR(new_device)); /* -ENOMEM */
6996
6997         /* Safe because we are under uuid_mutex */
6998         if (device->name) {
6999                 name = rcu_string_strdup(device->name->str, GFP_NOFS);
7000                 BUG_ON(!name); /* -ENOMEM */
7001                 rcu_assign_pointer(new_device->name, name);
7002         }
7003
7004         list_replace_rcu(&device->dev_list, &new_device->dev_list);
7005         new_device->fs_devices = device->fs_devices;
7006
7007         call_rcu(&device->rcu, free_device);
7008 }