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 "compat.h"
  29 #include "ctree.h"
  30 #include "extent_map.h"
  31 #include "disk-io.h"
  32 #include "transaction.h"
  33 #include "print-tree.h"
  34 #include "volumes.h"
  35 #include "async-thread.h"
  36 #include "check-integrity.h"
  37 #include "rcu-string.h"
  38 #include "math.h"
  39 #include "dev-replace.h"
  40
  41 static int init_first_rw_device(struct btrfs_trans_handle *trans,
  42                                 struct btrfs_root *root,
  43                                 struct btrfs_device *device);
  44 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
  45 static void __btrfs_reset_dev_stats(struct btrfs_device *dev);
  46 static void btrfs_dev_stat_print_on_load(struct btrfs_device *device);
  47
  48 static DEFINE_MUTEX(uuid_mutex);
  49 static LIST_HEAD(fs_uuids);
  50
  51 static void lock_chunks(struct btrfs_root *root)
  52 {
  53         mutex_lock(&root->fs_info->chunk_mutex);
  54 }
  55
  56 static void unlock_chunks(struct btrfs_root *root)
  57 {
  58         mutex_unlock(&root->fs_info->chunk_mutex);
  59 }
  60
  61 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
  62 {
  63         struct btrfs_device *device;
  64         WARN_ON(fs_devices->opened);
  65         while (!list_empty(&fs_devices->devices)) {
  66                 device = list_entry(fs_devices->devices.next,
  67                                     struct btrfs_device, dev_list);
  68                 list_del(&device->dev_list);
  69                 rcu_string_free(device->name);
  70                 kfree(device);
  71         }
  72         kfree(fs_devices);
  73 }
  74
  75 static void btrfs_kobject_uevent(struct block_device *bdev,
  76                                  enum kobject_action action)
  77 {
  78         int ret;
  79
  80         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
  81         if (ret)
  82                 pr_warn("Sending event '%d' to kobject: '%s' (%p): failed\n",
  83                         action,
  84                         kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
  85                         &disk_to_dev(bdev->bd_disk)->kobj);
  86 }
  87
  88 void btrfs_cleanup_fs_uuids(void)
  89 {
  90         struct btrfs_fs_devices *fs_devices;
  91
  92         while (!list_empty(&fs_uuids)) {
  93                 fs_devices = list_entry(fs_uuids.next,
  94                                         struct btrfs_fs_devices, list);
  95                 list_del(&fs_devices->list);
  96                 free_fs_devices(fs_devices);
  97         }
  98 }
  99
 100 static noinline struct btrfs_device *__find_device(struct list_head *head,
 101                                                    u64 devid, u8 *uuid)
 102 {
 103         struct btrfs_device *dev;
 104
 105         list_for_each_entry(dev, head, dev_list) {
 106                 if (dev->devid == devid &&
 107                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
 108                         return dev;
 109                 }
 110         }
 111         return NULL;
 112 }
 113
 114 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
 115 {
 116         struct btrfs_fs_devices *fs_devices;
 117
 118         list_for_each_entry(fs_devices, &fs_uuids, list) {
 119                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
 120                         return fs_devices;
 121         }
 122         return NULL;
 123 }
 124
 125 static int
 126 btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder,
 127                       int flush, struct block_device **bdev,
 128                       struct buffer_head **bh)
 129 {
 130         int ret;
 131
 132         *bdev = blkdev_get_by_path(device_path, flags, holder);
 133
 134         if (IS_ERR(*bdev)) {
 135                 ret = PTR_ERR(*bdev);
 136                 printk(KERN_INFO "btrfs: open %s failed\n", device_path);
 137                 goto error;
 138         }
 139
 140         if (flush)
 141                 filemap_write_and_wait((*bdev)->bd_inode->i_mapping);
 142         ret = set_blocksize(*bdev, 4096);
 143         if (ret) {
 144                 blkdev_put(*bdev, flags);
 145                 goto error;
 146         }
 147         invalidate_bdev(*bdev);
 148         *bh = btrfs_read_dev_super(*bdev);
 149         if (!*bh) {
 150                 ret = -EINVAL;
 151                 blkdev_put(*bdev, flags);
 152                 goto error;
 153         }
 154
 155         return 0;
 156
 157 error:
 158         *bdev = NULL;
 159         *bh = NULL;
 160         return ret;
 161 }
 162
 163 static void requeue_list(struct btrfs_pending_bios *pending_bios,
 164                         struct bio *head, struct bio *tail)
 165 {
 166
 167         struct bio *old_head;
 168
 169         old_head = pending_bios->head;
 170         pending_bios->head = head;
 171         if (pending_bios->tail)
 172                 tail->bi_next = old_head;
 173         else
 174                 pending_bios->tail = tail;
 175 }
 176
 177 /*
 178  * we try to collect pending bios for a device so we don't get a large
 179  * number of procs sending bios down to the same device.  This greatly
 180  * improves the schedulers ability to collect and merge the bios.
 181  *
 182  * But, it also turns into a long list of bios to process and that is sure
 183  * to eventually make the worker thread block.  The solution here is to
 184  * make some progress and then put this work struct back at the end of
 185  * the list if the block device is congested.  This way, multiple devices
 186  * can make progress from a single worker thread.
 187  */
 188 static noinline void run_scheduled_bios(struct btrfs_device *device)
 189 {
 190         struct bio *pending;
 191         struct backing_dev_info *bdi;
 192         struct btrfs_fs_info *fs_info;
 193         struct btrfs_pending_bios *pending_bios;
 194         struct bio *tail;
 195         struct bio *cur;
 196         int again = 0;
 197         unsigned long num_run;
 198         unsigned long batch_run = 0;
 199         unsigned long limit;
 200         unsigned long last_waited = 0;
 201         int force_reg = 0;
 202         int sync_pending = 0;
 203         struct blk_plug plug;
 204
 205         /*
 206          * this function runs all the bios we've collected for
 207          * a particular device.  We don't want to wander off to
 208          * another device without first sending all of these down.
 209          * So, setup a plug here and finish it off before we return
 210          */
 211         blk_start_plug(&plug);
 212
 213         bdi = blk_get_backing_dev_info(device->bdev);
 214         fs_info = device->dev_root->fs_info;
 215         limit = btrfs_async_submit_limit(fs_info);
 216         limit = limit * 2 / 3;
 217
 218 loop:
 219         spin_lock(&device->io_lock);
 220
 221 loop_lock:
 222         num_run = 0;
 223
 224         /* take all the bios off the list at once and process them
 225          * later on (without the lock held).  But, remember the
 226          * tail and other pointers so the bios can be properly reinserted
 227          * into the list if we hit congestion
 228          */
 229         if (!force_reg && device->pending_sync_bios.head) {
 230                 pending_bios = &device->pending_sync_bios;
 231                 force_reg = 1;
 232         } else {
 233                 pending_bios = &device->pending_bios;
 234                 force_reg = 0;
 235         }
 236
 237         pending = pending_bios->head;
 238         tail = pending_bios->tail;
 239         WARN_ON(pending && !tail);
 240
 241         /*
 242          * if pending was null this time around, no bios need processing
 243          * at all and we can stop.  Otherwise it'll loop back up again
 244          * and do an additional check so no bios are missed.
 245          *
 246          * device->running_pending is used to synchronize with the
 247          * schedule_bio code.
 248          */
 249         if (device->pending_sync_bios.head == NULL &&
 250             device->pending_bios.head == NULL) {
 251                 again = 0;
 252                 device->running_pending = 0;
 253         } else {
 254                 again = 1;
 255                 device->running_pending = 1;
 256         }
 257
 258         pending_bios->head = NULL;
 259         pending_bios->tail = NULL;
 260
 261         spin_unlock(&device->io_lock);
 262
 263         while (pending) {
 264
 265                 rmb();
 266                 /* we want to work on both lists, but do more bios on the
 267                  * sync list than the regular list
 268                  */
 269                 if ((num_run > 32 &&
 270                     pending_bios != &device->pending_sync_bios &&
 271                     device->pending_sync_bios.head) ||
 272                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
 273                     device->pending_bios.head)) {
 274                         spin_lock(&device->io_lock);
 275                         requeue_list(pending_bios, pending, tail);
 276                         goto loop_lock;
 277                 }
 278
 279                 cur = pending;
 280                 pending = pending->bi_next;
 281                 cur->bi_next = NULL;
 282
 283                 if (atomic_dec_return(&fs_info->nr_async_bios) < limit &&
 284                     waitqueue_active(&fs_info->async_submit_wait))
 285                         wake_up(&fs_info->async_submit_wait);
 286
 287                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
 288
 289                 /*
 290                  * if we're doing the sync list, record that our
 291                  * plug has some sync requests on it
 292                  *
 293                  * If we're doing the regular list and there are
 294                  * sync requests sitting around, unplug before
 295                  * we add more
 296                  */
 297                 if (pending_bios == &device->pending_sync_bios) {
 298                         sync_pending = 1;
 299                 } else if (sync_pending) {
 300                         blk_finish_plug(&plug);
 301                         blk_start_plug(&plug);
 302                         sync_pending = 0;
 303                 }
 304
 305                 btrfsic_submit_bio(cur->bi_rw, cur);
 306                 num_run++;
 307                 batch_run++;
 308                 if (need_resched())
 309                         cond_resched();
 310
 311                 /*
 312                  * we made progress, there is more work to do and the bdi
 313                  * is now congested.  Back off and let other work structs
 314                  * run instead
 315                  */
 316                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
 317                     fs_info->fs_devices->open_devices > 1) {
 318                         struct io_context *ioc;
 319
 320                         ioc = current->io_context;
 321
 322                         /*
 323                          * the main goal here is that we don't want to
 324                          * block if we're going to be able to submit
 325                          * more requests without blocking.
 326                          *
 327                          * This code does two great things, it pokes into
 328                          * the elevator code from a filesystem _and_
 329                          * it makes assumptions about how batching works.
 330                          */
 331                         if (ioc && ioc->nr_batch_requests > 0 &&
 332                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
 333                             (last_waited == 0 ||
 334                              ioc->last_waited == last_waited)) {
 335                                 /*
 336                                  * we want to go through our batch of
 337                                  * requests and stop.  So, we copy out
 338                                  * the ioc->last_waited time and test
 339                                  * against it before looping
 340                                  */
 341                                 last_waited = ioc->last_waited;
 342                                 if (need_resched())
 343                                         cond_resched();
 344                                 continue;
 345                         }
 346                         spin_lock(&device->io_lock);
 347                         requeue_list(pending_bios, pending, tail);
 348                         device->running_pending = 1;
 349
 350                         spin_unlock(&device->io_lock);
 351                         btrfs_requeue_work(&device->work);
 352                         goto done;
 353                 }
 354                 /* unplug every 64 requests just for good measure */
 355                 if (batch_run % 64 == 0) {
 356                         blk_finish_plug(&plug);
 357                         blk_start_plug(&plug);
 358                         sync_pending = 0;
 359                 }
 360         }
 361
 362         cond_resched();
 363         if (again)
 364                 goto loop;
 365
 366         spin_lock(&device->io_lock);
 367         if (device->pending_bios.head || device->pending_sync_bios.head)
 368                 goto loop_lock;
 369         spin_unlock(&device->io_lock);
 370
 371 done:
 372         blk_finish_plug(&plug);
 373 }
 374
 375 static void pending_bios_fn(struct btrfs_work *work)
 376 {
 377         struct btrfs_device *device;
 378
 379         device = container_of(work, struct btrfs_device, work);
 380         run_scheduled_bios(device);
 381 }
 382
 383 static noinline int device_list_add(const char *path,
 384                            struct btrfs_super_block *disk_super,
 385                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
 386 {
 387         struct btrfs_device *device;
 388         struct btrfs_fs_devices *fs_devices;
 389         struct rcu_string *name;
 390         u64 found_transid = btrfs_super_generation(disk_super);
 391
 392         fs_devices = find_fsid(disk_super->fsid);
 393         if (!fs_devices) {
 394                 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 395                 if (!fs_devices)
 396                         return -ENOMEM;
 397                 INIT_LIST_HEAD(&fs_devices->devices);
 398                 INIT_LIST_HEAD(&fs_devices->alloc_list);
 399                 list_add(&fs_devices->list, &fs_uuids);
 400                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
 401                 fs_devices->latest_devid = devid;
 402                 fs_devices->latest_trans = found_transid;
 403                 mutex_init(&fs_devices->device_list_mutex);
 404                 device = NULL;
 405         } else {
 406                 device = __find_device(&fs_devices->devices, devid,
 407                                        disk_super->dev_item.uuid);
 408         }
 409         if (!device) {
 410                 if (fs_devices->opened)
 411                         return -EBUSY;
 412
 413                 device = kzalloc(sizeof(*device), GFP_NOFS);
 414                 if (!device) {
 415                         /* we can safely leave the fs_devices entry around */
 416                         return -ENOMEM;
 417                 }
 418                 device->devid = devid;
 419                 device->dev_stats_valid = 0;
 420                 device->work.func = pending_bios_fn;
 421                 memcpy(device->uuid, disk_super->dev_item.uuid,
 422                        BTRFS_UUID_SIZE);
 423                 spin_lock_init(&device->io_lock);
 424
 425                 name = rcu_string_strdup(path, GFP_NOFS);
 426                 if (!name) {
 427                         kfree(device);
 428                         return -ENOMEM;
 429                 }
 430                 rcu_assign_pointer(device->name, name);
 431                 INIT_LIST_HEAD(&device->dev_alloc_list);
 432
 433                 /* init readahead state */
 434                 spin_lock_init(&device->reada_lock);
 435                 device->reada_curr_zone = NULL;
 436                 atomic_set(&device->reada_in_flight, 0);
 437                 device->reada_next = 0;
 438                 INIT_RADIX_TREE(&device->reada_zones, GFP_NOFS & ~__GFP_WAIT);
 439                 INIT_RADIX_TREE(&device->reada_extents, GFP_NOFS & ~__GFP_WAIT);
 440
 441                 mutex_lock(&fs_devices->device_list_mutex);
 442                 list_add_rcu(&device->dev_list, &fs_devices->devices);
 443                 mutex_unlock(&fs_devices->device_list_mutex);
 444
 445                 device->fs_devices = fs_devices;
 446                 fs_devices->num_devices++;
 447         } else if (!device->name || strcmp(device->name->str, path)) {
 448                 name = rcu_string_strdup(path, GFP_NOFS);
 449                 if (!name)
 450                         return -ENOMEM;
 451                 rcu_string_free(device->name);
 452                 rcu_assign_pointer(device->name, name);
 453                 if (device->missing) {
 454                         fs_devices->missing_devices--;
 455                         device->missing = 0;
 456                 }
 457         }
 458
 459         if (found_transid > fs_devices->latest_trans) {
 460                 fs_devices->latest_devid = devid;
 461                 fs_devices->latest_trans = found_transid;
 462         }
 463         *fs_devices_ret = fs_devices;
 464         return 0;
 465 }
 466
 467 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
 468 {
 469         struct btrfs_fs_devices *fs_devices;
 470         struct btrfs_device *device;
 471         struct btrfs_device *orig_dev;
 472
 473         fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 474         if (!fs_devices)
 475                 return ERR_PTR(-ENOMEM);
 476
 477         INIT_LIST_HEAD(&fs_devices->devices);
 478         INIT_LIST_HEAD(&fs_devices->alloc_list);
 479         INIT_LIST_HEAD(&fs_devices->list);
 480         mutex_init(&fs_devices->device_list_mutex);
 481         fs_devices->latest_devid = orig->latest_devid;
 482         fs_devices->latest_trans = orig->latest_trans;
 483         fs_devices->total_devices = orig->total_devices;
 484         memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));
 485
 486         /* We have held the volume lock, it is safe to get the devices. */
 487         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
 488                 struct rcu_string *name;
 489
 490                 device = kzalloc(sizeof(*device), GFP_NOFS);
 491                 if (!device)
 492                         goto error;
 493
 494                 /*
 495                  * This is ok to do without rcu read locked because we hold the
 496                  * uuid mutex so nothing we touch in here is going to disappear.
 497                  */
 498                 name = rcu_string_strdup(orig_dev->name->str, GFP_NOFS);
 499                 if (!name) {
 500                         kfree(device);
 501                         goto error;
 502                 }
 503                 rcu_assign_pointer(device->name, name);
 504
 505                 device->devid = orig_dev->devid;
 506                 device->work.func = pending_bios_fn;
 507                 memcpy(device->uuid, orig_dev->uuid, sizeof(device->uuid));
 508                 spin_lock_init(&device->io_lock);
 509                 INIT_LIST_HEAD(&device->dev_list);
 510                 INIT_LIST_HEAD(&device->dev_alloc_list);
 511
 512                 list_add(&device->dev_list, &fs_devices->devices);
 513                 device->fs_devices = fs_devices;
 514                 fs_devices->num_devices++;
 515         }
 516         return fs_devices;
 517 error:
 518         free_fs_devices(fs_devices);
 519         return ERR_PTR(-ENOMEM);
 520 }
 521
 522 void btrfs_close_extra_devices(struct btrfs_fs_info *fs_info,
 523                                struct btrfs_fs_devices *fs_devices, int step)
 524 {
 525         struct btrfs_device *device, *next;
 526
 527         struct block_device *latest_bdev = NULL;
 528         u64 latest_devid = 0;
 529         u64 latest_transid = 0;
 530
 531         mutex_lock(&uuid_mutex);
 532 again:
 533         /* This is the initialized path, it is safe to release the devices. */
 534         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
 535                 if (device->in_fs_metadata) {
 536                         if (!device->is_tgtdev_for_dev_replace &&
 537                             (!latest_transid ||
 538                              device->generation > latest_transid)) {
 539                                 latest_devid = device->devid;
 540                                 latest_transid = device->generation;
 541                                 latest_bdev = device->bdev;
 542                         }
 543                         continue;
 544                 }
 545
 546                 if (device->devid == BTRFS_DEV_REPLACE_DEVID) {
 547                         /*
 548                          * In the first step, keep the device which has
 549                          * the correct fsid and the devid that is used
 550                          * for the dev_replace procedure.
 551                          * In the second step, the dev_replace state is
 552                          * read from the device tree and it is known
 553                          * whether the procedure is really active or
 554                          * not, which means whether this device is
 555                          * used or whether it should be removed.
 556                          */
 557                         if (step == 0 || device->is_tgtdev_for_dev_replace) {
 558                                 continue;
 559                         }
 560                 }
 561                 if (device->bdev) {
 562                         blkdev_put(device->bdev, device->mode);
 563                         device->bdev = NULL;
 564                         fs_devices->open_devices--;
 565                 }
 566                 if (device->writeable) {
 567                         list_del_init(&device->dev_alloc_list);
 568                         device->writeable = 0;
 569                         if (!device->is_tgtdev_for_dev_replace)
 570                                 fs_devices->rw_devices--;
 571                 }
 572                 list_del_init(&device->dev_list);
 573                 fs_devices->num_devices--;
 574                 rcu_string_free(device->name);
 575                 kfree(device);
 576         }
 577
 578         if (fs_devices->seed) {
 579                 fs_devices = fs_devices->seed;
 580                 goto again;
 581         }
 582
 583         fs_devices->latest_bdev = latest_bdev;
 584         fs_devices->latest_devid = latest_devid;
 585         fs_devices->latest_trans = latest_transid;
 586
 587         mutex_unlock(&uuid_mutex);
 588 }
 589
 590 static void __free_device(struct work_struct *work)
 591 {
 592         struct btrfs_device *device;
 593
 594         device = container_of(work, struct btrfs_device, rcu_work);
 595
 596         if (device->bdev)
 597                 blkdev_put(device->bdev, device->mode);
 598
 599         rcu_string_free(device->name);
 600         kfree(device);
 601 }
 602
 603 static void free_device(struct rcu_head *head)
 604 {
 605         struct btrfs_device *device;
 606
 607         device = container_of(head, struct btrfs_device, rcu);
 608
 609         INIT_WORK(&device->rcu_work, __free_device);
 610         schedule_work(&device->rcu_work);
 611 }
 612
 613 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 614 {
 615         struct btrfs_device *device;
 616
 617         if (--fs_devices->opened > 0)
 618                 return 0;
 619
 620         mutex_lock(&fs_devices->device_list_mutex);
 621         list_for_each_entry(device, &fs_devices->devices, dev_list) {
 622                 struct btrfs_device *new_device;
 623                 struct rcu_string *name;
 624
 625                 if (device->bdev)
 626                         fs_devices->open_devices--;
 627
 628                 if (device->writeable && !device->is_tgtdev_for_dev_replace) {
 629                         list_del_init(&device->dev_alloc_list);
 630                         fs_devices->rw_devices--;
 631                 }
 632
 633                 if (device->can_discard)
 634                         fs_devices->num_can_discard--;
 635
 636                 new_device = kmalloc(sizeof(*new_device), GFP_NOFS);
 637                 BUG_ON(!new_device); /* -ENOMEM */
 638                 memcpy(new_device, device, sizeof(*new_device));
 639
 640                 /* Safe because we are under uuid_mutex */
 641                 if (device->name) {
 642                         name = rcu_string_strdup(device->name->str, GFP_NOFS);
 643                         BUG_ON(device->name && !name); /* -ENOMEM */
 644                         rcu_assign_pointer(new_device->name, name);
 645                 }
 646                 new_device->bdev = NULL;
 647                 new_device->writeable = 0;
 648                 new_device->in_fs_metadata = 0;
 649                 new_device->can_discard = 0;
 650                 list_replace_rcu(&device->dev_list, &new_device->dev_list);
 651
 652                 call_rcu(&device->rcu, free_device);
 653         }
 654         mutex_unlock(&fs_devices->device_list_mutex);
 655
 656         WARN_ON(fs_devices->open_devices);
 657         WARN_ON(fs_devices->rw_devices);
 658         fs_devices->opened = 0;
 659         fs_devices->seeding = 0;
 660
 661         return 0;
 662 }
 663
 664 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 665 {
 666         struct btrfs_fs_devices *seed_devices = NULL;
 667         int ret;
 668
 669         mutex_lock(&uuid_mutex);
 670         ret = __btrfs_close_devices(fs_devices);
 671         if (!fs_devices->opened) {
 672                 seed_devices = fs_devices->seed;
 673                 fs_devices->seed = NULL;
 674         }
 675         mutex_unlock(&uuid_mutex);
 676
 677         while (seed_devices) {
 678                 fs_devices = seed_devices;
 679                 seed_devices = fs_devices->seed;
 680                 __btrfs_close_devices(fs_devices);
 681                 free_fs_devices(fs_devices);
 682         }
 683         return ret;
 684 }
 685
 686 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 687                                 fmode_t flags, void *holder)
 688 {
 689         struct request_queue *q;
 690         struct block_device *bdev;
 691         struct list_head *head = &fs_devices->devices;
 692         struct btrfs_device *device;
 693         struct block_device *latest_bdev = NULL;
 694         struct buffer_head *bh;
 695         struct btrfs_super_block *disk_super;
 696         u64 latest_devid = 0;
 697         u64 latest_transid = 0;
 698         u64 devid;
 699         int seeding = 1;
 700         int ret = 0;
 701
 702         flags |= FMODE_EXCL;
 703
 704         list_for_each_entry(device, head, dev_list) {
 705                 if (device->bdev)
 706                         continue;
 707                 if (!device->name)
 708                         continue;
 709
 710                 ret = btrfs_get_bdev_and_sb(device->name->str, flags, holder, 1,
 711                                             &bdev, &bh);
 712                 if (ret)
 713                         continue;
 714
 715                 disk_super = (struct btrfs_super_block *)bh->b_data;
 716                 devid = btrfs_stack_device_id(&disk_super->dev_item);
 717                 if (devid != device->devid)
 718                         goto error_brelse;
 719
 720                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
 721                            BTRFS_UUID_SIZE))
 722                         goto error_brelse;
 723
 724                 device->generation = btrfs_super_generation(disk_super);
 725                 if (!latest_transid || device->generation > latest_transid) {
 726                         latest_devid = devid;
 727                         latest_transid = device->generation;
 728                         latest_bdev = bdev;
 729                 }
 730
 731                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
 732                         device->writeable = 0;
 733                 } else {
 734                         device->writeable = !bdev_read_only(bdev);
 735                         seeding = 0;
 736                 }
 737
 738                 q = bdev_get_queue(bdev);
 739                 if (blk_queue_discard(q)) {
 740                         device->can_discard = 1;
 741                         fs_devices->num_can_discard++;
 742                 }
 743
 744                 device->bdev = bdev;
 745                 device->in_fs_metadata = 0;
 746                 device->mode = flags;
 747
 748                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
 749                         fs_devices->rotating = 1;
 750
 751                 fs_devices->open_devices++;
 752                 if (device->writeable && !device->is_tgtdev_for_dev_replace) {
 753                         fs_devices->rw_devices++;
 754                         list_add(&device->dev_alloc_list,
 755                                  &fs_devices->alloc_list);
 756                 }
 757                 brelse(bh);
 758                 continue;
 759
 760 error_brelse:
 761                 brelse(bh);
 762                 blkdev_put(bdev, flags);
 763                 continue;
 764         }
 765         if (fs_devices->open_devices == 0) {
 766                 ret = -EINVAL;
 767                 goto out;
 768         }
 769         fs_devices->seeding = seeding;
 770         fs_devices->opened = 1;
 771         fs_devices->latest_bdev = latest_bdev;
 772         fs_devices->latest_devid = latest_devid;
 773         fs_devices->latest_trans = latest_transid;
 774         fs_devices->total_rw_bytes = 0;
 775 out:
 776         return ret;
 777 }
 778
 779 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 780                        fmode_t flags, void *holder)
 781 {
 782         int ret;
 783
 784         mutex_lock(&uuid_mutex);
 785         if (fs_devices->opened) {
 786                 fs_devices->opened++;
 787                 ret = 0;
 788         } else {
 789                 ret = __btrfs_open_devices(fs_devices, flags, holder);
 790         }
 791         mutex_unlock(&uuid_mutex);
 792         return ret;
 793 }
 794
 795 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 796                           struct btrfs_fs_devices **fs_devices_ret)
 797 {
 798         struct btrfs_super_block *disk_super;
 799         struct block_device *bdev;
 800         struct buffer_head *bh;
 801         int ret;
 802         u64 devid;
 803         u64 transid;
 804         u64 total_devices;
 805
 806         flags |= FMODE_EXCL;
 807         mutex_lock(&uuid_mutex);
 808         ret = btrfs_get_bdev_and_sb(path, flags, holder, 0, &bdev, &bh);
 809         if (ret)
 810                 goto error;
 811         disk_super = (struct btrfs_super_block *)bh->b_data;
 812         devid = btrfs_stack_device_id(&disk_super->dev_item);
 813         transid = btrfs_super_generation(disk_super);
 814         total_devices = btrfs_super_num_devices(disk_super);
 815         if (disk_super->label[0]) {
 816                 if (disk_super->label[BTRFS_LABEL_SIZE - 1])
 817                         disk_super->label[BTRFS_LABEL_SIZE - 1] = '\0';
 818                 printk(KERN_INFO "device label %s ", disk_super->label);
 819         } else {
 820                 printk(KERN_INFO "device fsid %pU ", disk_super->fsid);
 821         }
 822         printk(KERN_CONT "devid %llu transid %llu %s\n",
 823                (unsigned long long)devid, (unsigned long long)transid, path);
 824         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
 825         if (!ret && fs_devices_ret)
 826                 (*fs_devices_ret)->total_devices = total_devices;
 827         brelse(bh);
 828         blkdev_put(bdev, flags);
 829 error:
 830         mutex_unlock(&uuid_mutex);
 831         return ret;
 832 }
 833
 834 /* helper to account the used device space in the range */
 835 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
 836                                    u64 end, u64 *length)
 837 {
 838         struct btrfs_key key;
 839         struct btrfs_root *root = device->dev_root;
 840         struct btrfs_dev_extent *dev_extent;
 841         struct btrfs_path *path;
 842         u64 extent_end;
 843         int ret;
 844         int slot;
 845         struct extent_buffer *l;
 846
 847         *length = 0;
 848
 849         if (start >= device->total_bytes || device->is_tgtdev_for_dev_replace)
 850                 return 0;
 851
 852         path = btrfs_alloc_path();
 853         if (!path)
 854                 return -ENOMEM;
 855         path->reada = 2;
 856
 857         key.objectid = device->devid;
 858         key.offset = start;
 859         key.type = BTRFS_DEV_EXTENT_KEY;
 860
 861         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 862         if (ret < 0)
 863                 goto out;
 864         if (ret > 0) {
 865                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
 866                 if (ret < 0)
 867                         goto out;
 868         }
 869
 870         while (1) {
 871                 l = path->nodes[0];
 872                 slot = path->slots[0];
 873                 if (slot >= btrfs_header_nritems(l)) {
 874                         ret = btrfs_next_leaf(root, path);
 875                         if (ret == 0)
 876                                 continue;
 877                         if (ret < 0)
 878                                 goto out;
 879
 880                         break;
 881                 }
 882                 btrfs_item_key_to_cpu(l, &key, slot);
 883
 884                 if (key.objectid < device->devid)
 885                         goto next;
 886
 887                 if (key.objectid > device->devid)
 888                         break;
 889
 890                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
 891                         goto next;
 892
 893                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
 894                 extent_end = key.offset + btrfs_dev_extent_length(l,
 895                                                                   dev_extent);
 896                 if (key.offset <= start && extent_end > end) {
 897                         *length = end - start + 1;
 898                         break;
 899                 } else if (key.offset <= start && extent_end > start)
 900                         *length += extent_end - start;
 901                 else if (key.offset > start && extent_end <= end)
 902                         *length += extent_end - key.offset;
 903                 else if (key.offset > start && key.offset <= end) {
 904                         *length += end - key.offset + 1;
 905                         break;
 906                 } else if (key.offset > end)
 907                         break;
 908
 909 next:
 910                 path->slots[0]++;
 911         }
 912         ret = 0;
 913 out:
 914         btrfs_free_path(path);
 915         return ret;
 916 }
 917
 918 /*
 919  * find_free_dev_extent - find free space in the specified device
 920  * @device:     the device which we search the free space in
 921  * @num_bytes:  the size of the free space that we need
 922  * @start:      store the start of the free space.
 923  * @len:        the size of the free space. that we find, or the size of the max
 924  *              free space if we don't find suitable free space
 925  *
 926  * this uses a pretty simple search, the expectation is that it is
 927  * called very infrequently and that a given device has a small number
 928  * of extents
 929  *
 930  * @start is used to store the start of the free space if we find. But if we
 931  * don't find suitable free space, it will be used to store the start position
 932  * of the max free space.
 933  *
 934  * @len is used to store the size of the free space that we find.
 935  * But if we don't find suitable free space, it is used to store the size of
 936  * the max free space.
 937  */
 938 int find_free_dev_extent(struct btrfs_device *device, u64 num_bytes,
 939                          u64 *start, u64 *len)
 940 {
 941         struct btrfs_key key;
 942         struct btrfs_root *root = device->dev_root;
 943         struct btrfs_dev_extent *dev_extent;
 944         struct btrfs_path *path;
 945         u64 hole_size;
 946         u64 max_hole_start;
 947         u64 max_hole_size;
 948         u64 extent_end;
 949         u64 search_start;
 950         u64 search_end = device->total_bytes;
 951         int ret;
 952         int slot;
 953         struct extent_buffer *l;
 954
 955         /* FIXME use last free of some kind */
 956
 957         /* we don't want to overwrite the superblock on the drive,
 958          * so we make sure to start at an offset of at least 1MB
 959          */
 960         search_start = max(root->fs_info->alloc_start, 1024ull * 1024);
 961
 962         max_hole_start = search_start;
 963         max_hole_size = 0;
 964         hole_size = 0;
 965
 966         if (search_start >= search_end || device->is_tgtdev_for_dev_replace) {
 967                 ret = -ENOSPC;
 968                 goto error;
 969         }
 970
 971         path = btrfs_alloc_path();
 972         if (!path) {
 973                 ret = -ENOMEM;
 974                 goto error;
 975         }
 976         path->reada = 2;
 977
 978         key.objectid = device->devid;
 979         key.offset = search_start;
 980         key.type = BTRFS_DEV_EXTENT_KEY;
 981
 982         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 983         if (ret < 0)
 984                 goto out;
 985         if (ret > 0) {
 986                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
 987                 if (ret < 0)
 988                         goto out;
 989         }
 990
 991         while (1) {
 992                 l = path->nodes[0];
 993                 slot = path->slots[0];
 994                 if (slot >= btrfs_header_nritems(l)) {
 995                         ret = btrfs_next_leaf(root, path);
 996                         if (ret == 0)
 997                                 continue;
 998                         if (ret < 0)
 999                                 goto out;
1000
1001                         break;
1002                 }
1003                 btrfs_item_key_to_cpu(l, &key, slot);
1004
1005                 if (key.objectid < device->devid)
1006                         goto next;
1007
1008                 if (key.objectid > device->devid)
1009                         break;
1010
1011                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
1012                         goto next;
1013
1014                 if (key.offset > search_start) {
1015                         hole_size = key.offset - search_start;
1016
1017                         if (hole_size > max_hole_size) {
1018                                 max_hole_start = search_start;
1019                                 max_hole_size = hole_size;
1020                         }
1021
1022                         /*
1023                          * If this free space is greater than which we need,
1024                          * it must be the max free space that we have found
1025                          * until now, so max_hole_start must point to the start
1026                          * of this free space and the length of this free space
1027                          * is stored in max_hole_size. Thus, we return
1028                          * max_hole_start and max_hole_size and go back to the
1029                          * caller.
1030                          */
1031                         if (hole_size >= num_bytes) {
1032                                 ret = 0;
1033                                 goto out;
1034                         }
1035                 }
1036
1037                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1038                 extent_end = key.offset + btrfs_dev_extent_length(l,
1039                                                                   dev_extent);
1040                 if (extent_end > search_start)
1041                         search_start = extent_end;
1042 next:
1043                 path->slots[0]++;
1044                 cond_resched();
1045         }
1046
1047         /*
1048          * At this point, search_start should be the end of
1049          * allocated dev extents, and when shrinking the device,
1050          * search_end may be smaller than search_start.
1051          */
1052         if (search_end > search_start)
1053                 hole_size = search_end - search_start;
1054
1055         if (hole_size > max_hole_size) {
1056                 max_hole_start = search_start;
1057                 max_hole_size = hole_size;
1058         }
1059
1060         /* See above. */
1061         if (hole_size < num_bytes)
1062                 ret = -ENOSPC;
1063         else
1064                 ret = 0;
1065
1066 out:
1067         btrfs_free_path(path);
1068 error:
1069         *start = max_hole_start;
1070         if (len)
1071                 *len = max_hole_size;
1072         return ret;
1073 }
1074
1075 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
1076                           struct btrfs_device *device,
1077                           u64 start)
1078 {
1079         int ret;
1080         struct btrfs_path *path;
1081         struct btrfs_root *root = device->dev_root;
1082         struct btrfs_key key;
1083         struct btrfs_key found_key;
1084         struct extent_buffer *leaf = NULL;
1085         struct btrfs_dev_extent *extent = NULL;
1086
1087         path = btrfs_alloc_path();
1088         if (!path)
1089                 return -ENOMEM;
1090
1091         key.objectid = device->devid;
1092         key.offset = start;
1093         key.type = BTRFS_DEV_EXTENT_KEY;
1094 again:
1095         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1096         if (ret > 0) {
1097                 ret = btrfs_previous_item(root, path, key.objectid,
1098                                           BTRFS_DEV_EXTENT_KEY);
1099                 if (ret)
1100                         goto out;
1101                 leaf = path->nodes[0];
1102                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1103                 extent = btrfs_item_ptr(leaf, path->slots[0],
1104                                         struct btrfs_dev_extent);
1105                 BUG_ON(found_key.offset > start || found_key.offset +
1106                        btrfs_dev_extent_length(leaf, extent) < start);
1107                 key = found_key;
1108                 btrfs_release_path(path);
1109                 goto again;
1110         } else if (ret == 0) {
1111                 leaf = path->nodes[0];
1112                 extent = btrfs_item_ptr(leaf, path->slots[0],
1113                                         struct btrfs_dev_extent);
1114         } else {
1115                 btrfs_error(root->fs_info, ret, "Slot search failed");
1116                 goto out;
1117         }
1118
1119         if (device->bytes_used > 0) {
1120                 u64 len = btrfs_dev_extent_length(leaf, extent);
1121                 device->bytes_used -= len;
1122                 spin_lock(&root->fs_info->free_chunk_lock);
1123                 root->fs_info->free_chunk_space += len;
1124                 spin_unlock(&root->fs_info->free_chunk_lock);
1125         }
1126         ret = btrfs_del_item(trans, root, path);
1127         if (ret) {
1128                 btrfs_error(root->fs_info, ret,
1129                             "Failed to remove dev extent item");
1130         }
1131 out:
1132         btrfs_free_path(path);
1133         return ret;
1134 }
1135
1136 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
1137                            struct btrfs_device *device,
1138                            u64 chunk_tree, u64 chunk_objectid,
1139                            u64 chunk_offset, u64 start, u64 num_bytes)
1140 {
1141         int ret;
1142         struct btrfs_path *path;
1143         struct btrfs_root *root = device->dev_root;
1144         struct btrfs_dev_extent *extent;
1145         struct extent_buffer *leaf;
1146         struct btrfs_key key;
1147
1148         WARN_ON(!device->in_fs_metadata);
1149         WARN_ON(device->is_tgtdev_for_dev_replace);
1150         path = btrfs_alloc_path();
1151         if (!path)
1152                 return -ENOMEM;
1153
1154         key.objectid = device->devid;
1155         key.offset = start;
1156         key.type = BTRFS_DEV_EXTENT_KEY;
1157         ret = btrfs_insert_empty_item(trans, root, path, &key,
1158                                       sizeof(*extent));
1159         if (ret)
1160                 goto out;
1161
1162         leaf = path->nodes[0];
1163         extent = btrfs_item_ptr(leaf, path->slots[0],
1164                                 struct btrfs_dev_extent);
1165         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
1166         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
1167         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
1168
1169         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
1170                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
1171                     BTRFS_UUID_SIZE);
1172
1173         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
1174         btrfs_mark_buffer_dirty(leaf);
1175 out:
1176         btrfs_free_path(path);
1177         return ret;
1178 }
1179
1180 static noinline int find_next_chunk(struct btrfs_root *root,
1181                                     u64 objectid, u64 *offset)
1182 {
1183         struct btrfs_path *path;
1184         int ret;
1185         struct btrfs_key key;
1186         struct btrfs_chunk *chunk;
1187         struct btrfs_key found_key;
1188
1189         path = btrfs_alloc_path();
1190         if (!path)
1191                 return -ENOMEM;
1192
1193         key.objectid = objectid;
1194         key.offset = (u64)-1;
1195         key.type = BTRFS_CHUNK_ITEM_KEY;
1196
1197         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1198         if (ret < 0)
1199                 goto error;
1200
1201         BUG_ON(ret == 0); /* Corruption */
1202
1203         ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
1204         if (ret) {
1205                 *offset = 0;
1206         } else {
1207                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1208                                       path->slots[0]);
1209                 if (found_key.objectid != objectid)
1210                         *offset = 0;
1211                 else {
1212                         chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
1213                                                struct btrfs_chunk);
1214                         *offset = found_key.offset +
1215                                 btrfs_chunk_length(path->nodes[0], chunk);
1216                 }
1217         }
1218         ret = 0;
1219 error:
1220         btrfs_free_path(path);
1221         return ret;
1222 }
1223
1224 static noinline int find_next_devid(struct btrfs_root *root, u64 *objectid)
1225 {
1226         int ret;
1227         struct btrfs_key key;
1228         struct btrfs_key found_key;
1229         struct btrfs_path *path;
1230
1231         root = root->fs_info->chunk_root;
1232
1233         path = btrfs_alloc_path();
1234         if (!path)
1235                 return -ENOMEM;
1236
1237         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1238         key.type = BTRFS_DEV_ITEM_KEY;
1239         key.offset = (u64)-1;
1240
1241         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1242         if (ret < 0)
1243                 goto error;
1244
1245         BUG_ON(ret == 0); /* Corruption */
1246
1247         ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
1248                                   BTRFS_DEV_ITEM_KEY);
1249         if (ret) {
1250                 *objectid = 1;
1251         } else {
1252                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1253                                       path->slots[0]);
1254                 *objectid = found_key.offset + 1;
1255         }
1256         ret = 0;
1257 error:
1258         btrfs_free_path(path);
1259         return ret;
1260 }
1261
1262 /*
1263  * the device information is stored in the chunk root
1264  * the btrfs_device struct should be fully filled in
1265  */
1266 int btrfs_add_device(struct btrfs_trans_handle *trans,
1267                      struct btrfs_root *root,
1268                      struct btrfs_device *device)
1269 {
1270         int ret;
1271         struct btrfs_path *path;
1272         struct btrfs_dev_item *dev_item;
1273         struct extent_buffer *leaf;
1274         struct btrfs_key key;
1275         unsigned long ptr;
1276
1277         root = root->fs_info->chunk_root;
1278
1279         path = btrfs_alloc_path();
1280         if (!path)
1281                 return -ENOMEM;
1282
1283         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1284         key.type = BTRFS_DEV_ITEM_KEY;
1285         key.offset = device->devid;
1286
1287         ret = btrfs_insert_empty_item(trans, root, path, &key,
1288                                       sizeof(*dev_item));
1289         if (ret)
1290                 goto out;
1291
1292         leaf = path->nodes[0];
1293         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1294
1295         btrfs_set_device_id(leaf, dev_item, device->devid);
1296         btrfs_set_device_generation(leaf, dev_item, 0);
1297         btrfs_set_device_type(leaf, dev_item, device->type);
1298         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1299         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1300         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1301         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
1302         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1303         btrfs_set_device_group(leaf, dev_item, 0);
1304         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1305         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1306         btrfs_set_device_start_offset(leaf, dev_item, 0);
1307
1308         ptr = (unsigned long)btrfs_device_uuid(dev_item);
1309         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1310         ptr = (unsigned long)btrfs_device_fsid(dev_item);
1311         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1312         btrfs_mark_buffer_dirty(leaf);
1313
1314         ret = 0;
1315 out:
1316         btrfs_free_path(path);
1317         return ret;
1318 }
1319
1320 static int btrfs_rm_dev_item(struct btrfs_root *root,
1321                              struct btrfs_device *device)
1322 {
1323         int ret;
1324         struct btrfs_path *path;
1325         struct btrfs_key key;
1326         struct btrfs_trans_handle *trans;
1327
1328         root = root->fs_info->chunk_root;
1329
1330         path = btrfs_alloc_path();
1331         if (!path)
1332                 return -ENOMEM;
1333
1334         trans = btrfs_start_transaction(root, 0);
1335         if (IS_ERR(trans)) {
1336                 btrfs_free_path(path);
1337                 return PTR_ERR(trans);
1338         }
1339         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1340         key.type = BTRFS_DEV_ITEM_KEY;
1341         key.offset = device->devid;
1342         lock_chunks(root);
1343
1344         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1345         if (ret < 0)
1346                 goto out;
1347
1348         if (ret > 0) {
1349                 ret = -ENOENT;
1350                 goto out;
1351         }
1352
1353         ret = btrfs_del_item(trans, root, path);
1354         if (ret)
1355                 goto out;
1356 out:
1357         btrfs_free_path(path);
1358         unlock_chunks(root);
1359         btrfs_commit_transaction(trans, root);
1360         return ret;
1361 }
1362
1363 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1364 {
1365         struct btrfs_device *device;
1366         struct btrfs_device *next_device;
1367         struct block_device *bdev;
1368         struct buffer_head *bh = NULL;
1369         struct btrfs_super_block *disk_super;
1370         struct btrfs_fs_devices *cur_devices;
1371         u64 all_avail;
1372         u64 devid;
1373         u64 num_devices;
1374         u8 *dev_uuid;
1375         int ret = 0;
1376         bool clear_super = false;
1377
1378         mutex_lock(&uuid_mutex);
1379
1380         all_avail = root->fs_info->avail_data_alloc_bits |
1381                 root->fs_info->avail_system_alloc_bits |
1382                 root->fs_info->avail_metadata_alloc_bits;
1383
1384         num_devices = root->fs_info->fs_devices->num_devices;
1385         btrfs_dev_replace_lock(&root->fs_info->dev_replace);
1386         if (btrfs_dev_replace_is_ongoing(&root->fs_info->dev_replace)) {
1387                 WARN_ON(num_devices < 1);
1388                 num_devices--;
1389         }
1390         btrfs_dev_replace_unlock(&root->fs_info->dev_replace);
1391
1392         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) && num_devices <= 4) {
1393                 printk(KERN_ERR "btrfs: unable to go below four devices "
1394                        "on raid10\n");
1395                 ret = -EINVAL;
1396                 goto out;
1397         }
1398
1399         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) && num_devices <= 2) {
1400                 printk(KERN_ERR "btrfs: unable to go below two "
1401                        "devices on raid1\n");
1402                 ret = -EINVAL;
1403                 goto out;
1404         }
1405
1406         if (strcmp(device_path, "missing") == 0) {
1407                 struct list_head *devices;
1408                 struct btrfs_device *tmp;
1409
1410                 device = NULL;
1411                 devices = &root->fs_info->fs_devices->devices;
1412                 /*
1413                  * It is safe to read the devices since the volume_mutex
1414                  * is held.
1415                  */
1416                 list_for_each_entry(tmp, devices, dev_list) {
1417                         if (tmp->in_fs_metadata &&
1418                             !tmp->is_tgtdev_for_dev_replace &&
1419                             !tmp->bdev) {
1420                                 device = tmp;
1421                                 break;
1422                         }
1423                 }
1424                 bdev = NULL;
1425                 bh = NULL;
1426                 disk_super = NULL;
1427                 if (!device) {
1428                         printk(KERN_ERR "btrfs: no missing devices found to "
1429                                "remove\n");
1430                         goto out;
1431                 }
1432         } else {
1433                 ret = btrfs_get_bdev_and_sb(device_path,
1434                                             FMODE_WRITE | FMODE_EXCL,
1435                                             root->fs_info->bdev_holder, 0,
1436                                             &bdev, &bh);
1437                 if (ret)
1438                         goto out;
1439                 disk_super = (struct btrfs_super_block *)bh->b_data;
1440                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1441                 dev_uuid = disk_super->dev_item.uuid;
1442                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1443                                            disk_super->fsid);
1444                 if (!device) {
1445                         ret = -ENOENT;
1446                         goto error_brelse;
1447                 }
1448         }
1449
1450         if (device->is_tgtdev_for_dev_replace) {
1451                 pr_err("btrfs: unable to remove the dev_replace target dev\n");
1452                 ret = -EINVAL;
1453                 goto error_brelse;
1454         }
1455
1456         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1457                 printk(KERN_ERR "btrfs: unable to remove the only writeable "
1458                        "device\n");
1459                 ret = -EINVAL;
1460                 goto error_brelse;
1461         }
1462
1463         if (device->writeable) {
1464                 lock_chunks(root);
1465                 list_del_init(&device->dev_alloc_list);
1466                 unlock_chunks(root);
1467                 root->fs_info->fs_devices->rw_devices--;
1468                 clear_super = true;
1469         }
1470
1471         ret = btrfs_shrink_device(device, 0);
1472         if (ret)
1473                 goto error_undo;
1474
1475         /*
1476          * TODO: the superblock still includes this device in its num_devices
1477          * counter although write_all_supers() is not locked out. This
1478          * could give a filesystem state which requires a degraded mount.
1479          */
1480         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1481         if (ret)
1482                 goto error_undo;
1483
1484         spin_lock(&root->fs_info->free_chunk_lock);
1485         root->fs_info->free_chunk_space = device->total_bytes -
1486                 device->bytes_used;
1487         spin_unlock(&root->fs_info->free_chunk_lock);
1488
1489         device->in_fs_metadata = 0;
1490         btrfs_scrub_cancel_dev(root->fs_info, device);
1491
1492         /*
1493          * the device list mutex makes sure that we don't change
1494          * the device list while someone else is writing out all
1495          * the device supers.
1496          */
1497
1498         cur_devices = device->fs_devices;
1499         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1500         list_del_rcu(&device->dev_list);
1501
1502         device->fs_devices->num_devices--;
1503         device->fs_devices->total_devices--;
1504
1505         if (device->missing)
1506                 root->fs_info->fs_devices->missing_devices--;
1507
1508         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1509                                  struct btrfs_device, dev_list);
1510         if (device->bdev == root->fs_info->sb->s_bdev)
1511                 root->fs_info->sb->s_bdev = next_device->bdev;
1512         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1513                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1514
1515         if (device->bdev)
1516                 device->fs_devices->open_devices--;
1517
1518         call_rcu(&device->rcu, free_device);
1519         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1520
1521         num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
1522         btrfs_set_super_num_devices(root->fs_info->super_copy, num_devices);
1523
1524         if (cur_devices->open_devices == 0) {
1525                 struct btrfs_fs_devices *fs_devices;
1526                 fs_devices = root->fs_info->fs_devices;
1527                 while (fs_devices) {
1528                         if (fs_devices->seed == cur_devices)
1529                                 break;
1530                         fs_devices = fs_devices->seed;
1531                 }
1532                 fs_devices->seed = cur_devices->seed;
1533                 cur_devices->seed = NULL;
1534                 lock_chunks(root);
1535                 __btrfs_close_devices(cur_devices);
1536                 unlock_chunks(root);
1537                 free_fs_devices(cur_devices);
1538         }
1539
1540         root->fs_info->num_tolerated_disk_barrier_failures =
1541                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1542
1543         /*
1544          * at this point, the device is zero sized.  We want to
1545          * remove it from the devices list and zero out the old super
1546          */
1547         if (clear_super && disk_super) {
1548                 /* make sure this device isn't detected as part of
1549                  * the FS anymore
1550                  */
1551                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1552                 set_buffer_dirty(bh);
1553                 sync_dirty_buffer(bh);
1554         }
1555
1556         ret = 0;
1557
1558         /* Notify udev that device has changed */
1559         if (bdev)
1560                 btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
1561
1562 error_brelse:
1563         brelse(bh);
1564         if (bdev)
1565                 blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
1566 out:
1567         mutex_unlock(&uuid_mutex);
1568         return ret;
1569 error_undo:
1570         if (device->writeable) {
1571                 lock_chunks(root);
1572                 list_add(&device->dev_alloc_list,
1573                          &root->fs_info->fs_devices->alloc_list);
1574                 unlock_chunks(root);
1575                 root->fs_info->fs_devices->rw_devices++;
1576         }
1577         goto error_brelse;
1578 }
1579
1580 void btrfs_rm_dev_replace_srcdev(struct btrfs_fs_info *fs_info,
1581                                  struct btrfs_device *srcdev)
1582 {
1583         WARN_ON(!mutex_is_locked(&fs_info->fs_devices->device_list_mutex));
1584         list_del_rcu(&srcdev->dev_list);
1585         list_del_rcu(&srcdev->dev_alloc_list);
1586         fs_info->fs_devices->num_devices--;
1587         if (srcdev->missing) {
1588                 fs_info->fs_devices->missing_devices--;
1589                 fs_info->fs_devices->rw_devices++;
1590         }
1591         if (srcdev->can_discard)
1592                 fs_info->fs_devices->num_can_discard--;
1593         if (srcdev->bdev)
1594                 fs_info->fs_devices->open_devices--;
1595
1596         call_rcu(&srcdev->rcu, free_device);
1597 }
1598
1599 void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
1600                                       struct btrfs_device *tgtdev)
1601 {
1602         struct btrfs_device *next_device;
1603
1604         WARN_ON(!tgtdev);
1605         mutex_lock(&fs_info->fs_devices->device_list_mutex);
1606         if (tgtdev->bdev) {
1607                 btrfs_scratch_superblock(tgtdev);
1608                 fs_info->fs_devices->open_devices--;
1609         }
1610         fs_info->fs_devices->num_devices--;
1611         if (tgtdev->can_discard)
1612                 fs_info->fs_devices->num_can_discard++;
1613
1614         next_device = list_entry(fs_info->fs_devices->devices.next,
1615                                  struct btrfs_device, dev_list);
1616         if (tgtdev->bdev == fs_info->sb->s_bdev)
1617                 fs_info->sb->s_bdev = next_device->bdev;
1618         if (tgtdev->bdev == fs_info->fs_devices->latest_bdev)
1619                 fs_info->fs_devices->latest_bdev = next_device->bdev;
1620         list_del_rcu(&tgtdev->dev_list);
1621
1622         call_rcu(&tgtdev->rcu, free_device);
1623
1624         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1625 }
1626
1627 int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
1628                               struct btrfs_device **device)
1629 {
1630         int ret = 0;
1631         struct btrfs_super_block *disk_super;
1632         u64 devid;
1633         u8 *dev_uuid;
1634         struct block_device *bdev;
1635         struct buffer_head *bh;
1636
1637         *device = NULL;
1638         ret = btrfs_get_bdev_and_sb(device_path, FMODE_READ,
1639                                     root->fs_info->bdev_holder, 0, &bdev, &bh);
1640         if (ret)
1641                 return ret;
1642         disk_super = (struct btrfs_super_block *)bh->b_data;
1643         devid = btrfs_stack_device_id(&disk_super->dev_item);
1644         dev_uuid = disk_super->dev_item.uuid;
1645         *device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1646                                     disk_super->fsid);
1647         brelse(bh);
1648         if (!*device)
1649                 ret = -ENOENT;
1650         blkdev_put(bdev, FMODE_READ);
1651         return ret;
1652 }
1653
1654 int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
1655                                          char *device_path,
1656                                          struct btrfs_device **device)
1657 {
1658         *device = NULL;
1659         if (strcmp(device_path, "missing") == 0) {
1660                 struct list_head *devices;
1661                 struct btrfs_device *tmp;
1662
1663                 devices = &root->fs_info->fs_devices->devices;
1664                 /*
1665                  * It is safe to read the devices since the volume_mutex
1666                  * is held by the caller.
1667                  */
1668                 list_for_each_entry(tmp, devices, dev_list) {
1669                         if (tmp->in_fs_metadata && !tmp->bdev) {
1670                                 *device = tmp;
1671                                 break;
1672                         }
1673                 }
1674
1675                 if (!*device) {
1676                         pr_err("btrfs: no missing device found\n");
1677                         return -ENOENT;
1678                 }
1679
1680                 return 0;
1681         } else {
1682                 return btrfs_find_device_by_path(root, device_path, device);
1683         }
1684 }
1685
1686 /*
1687  * does all the dirty work required for changing file system's UUID.
1688  */
1689 static int btrfs_prepare_sprout(struct btrfs_root *root)
1690 {
1691         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
1692         struct btrfs_fs_devices *old_devices;
1693         struct btrfs_fs_devices *seed_devices;
1694         struct btrfs_super_block *disk_super = root->fs_info->super_copy;
1695         struct btrfs_device *device;
1696         u64 super_flags;
1697
1698         BUG_ON(!mutex_is_locked(&uuid_mutex));
1699         if (!fs_devices->seeding)
1700                 return -EINVAL;
1701
1702         seed_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
1703         if (!seed_devices)
1704                 return -ENOMEM;
1705
1706         old_devices = clone_fs_devices(fs_devices);
1707         if (IS_ERR(old_devices)) {
1708                 kfree(seed_devices);
1709                 return PTR_ERR(old_devices);
1710         }
1711
1712         list_add(&old_devices->list, &fs_uuids);
1713
1714         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
1715         seed_devices->opened = 1;
1716         INIT_LIST_HEAD(&seed_devices->devices);
1717         INIT_LIST_HEAD(&seed_devices->alloc_list);
1718         mutex_init(&seed_devices->device_list_mutex);
1719
1720         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1721         list_splice_init_rcu(&fs_devices->devices, &seed_devices->devices,
1722                               synchronize_rcu);
1723         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1724
1725         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
1726         list_for_each_entry(device, &seed_devices->devices, dev_list) {
1727                 device->fs_devices = seed_devices;
1728         }
1729
1730         fs_devices->seeding = 0;
1731         fs_devices->num_devices = 0;
1732         fs_devices->open_devices = 0;
1733         fs_devices->total_devices = 0;
1734         fs_devices->seed = seed_devices;
1735
1736         generate_random_uuid(fs_devices->fsid);
1737         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1738         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1739         super_flags = btrfs_super_flags(disk_super) &
1740                       ~BTRFS_SUPER_FLAG_SEEDING;
1741         btrfs_set_super_flags(disk_super, super_flags);
1742
1743         return 0;
1744 }
1745
1746 /*
1747  * strore the expected generation for seed devices in device items.
1748  */
1749 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
1750                                struct btrfs_root *root)
1751 {
1752         struct btrfs_path *path;
1753         struct extent_buffer *leaf;
1754         struct btrfs_dev_item *dev_item;
1755         struct btrfs_device *device;
1756         struct btrfs_key key;
1757         u8 fs_uuid[BTRFS_UUID_SIZE];
1758         u8 dev_uuid[BTRFS_UUID_SIZE];
1759         u64 devid;
1760         int ret;
1761
1762         path = btrfs_alloc_path();
1763         if (!path)
1764                 return -ENOMEM;
1765
1766         root = root->fs_info->chunk_root;
1767         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1768         key.offset = 0;
1769         key.type = BTRFS_DEV_ITEM_KEY;
1770
1771         while (1) {
1772                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1773                 if (ret < 0)
1774                         goto error;
1775
1776                 leaf = path->nodes[0];
1777 next_slot:
1778                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1779                         ret = btrfs_next_leaf(root, path);
1780                         if (ret > 0)
1781                                 break;
1782                         if (ret < 0)
1783                                 goto error;
1784                         leaf = path->nodes[0];
1785                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1786                         btrfs_release_path(path);
1787                         continue;
1788                 }
1789
1790                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1791                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
1792                     key.type != BTRFS_DEV_ITEM_KEY)
1793                         break;
1794
1795                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
1796                                           struct btrfs_dev_item);
1797                 devid = btrfs_device_id(leaf, dev_item);
1798                 read_extent_buffer(leaf, dev_uuid,
1799                                    (unsigned long)btrfs_device_uuid(dev_item),
1800                                    BTRFS_UUID_SIZE);
1801                 read_extent_buffer(leaf, fs_uuid,
1802                                    (unsigned long)btrfs_device_fsid(dev_item),
1803                                    BTRFS_UUID_SIZE);
1804                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1805                                            fs_uuid);
1806                 BUG_ON(!device); /* Logic error */
1807
1808                 if (device->fs_devices->seeding) {
1809                         btrfs_set_device_generation(leaf, dev_item,
1810                                                     device->generation);
1811                         btrfs_mark_buffer_dirty(leaf);
1812                 }
1813
1814                 path->slots[0]++;
1815                 goto next_slot;
1816         }
1817         ret = 0;
1818 error:
1819         btrfs_free_path(path);
1820         return ret;
1821 }
1822
1823 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
1824 {
1825         struct request_queue *q;
1826         struct btrfs_trans_handle *trans;
1827         struct btrfs_device *device;
1828         struct block_device *bdev;
1829         struct list_head *devices;
1830         struct super_block *sb = root->fs_info->sb;
1831         struct rcu_string *name;
1832         u64 total_bytes;
1833         int seeding_dev = 0;
1834         int ret = 0;
1835
1836         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
1837                 return -EROFS;
1838
1839         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
1840                                   root->fs_info->bdev_holder);
1841         if (IS_ERR(bdev))
1842                 return PTR_ERR(bdev);
1843
1844         if (root->fs_info->fs_devices->seeding) {
1845                 seeding_dev = 1;
1846                 down_write(&sb->s_umount);
1847                 mutex_lock(&uuid_mutex);
1848         }
1849
1850         filemap_write_and_wait(bdev->bd_inode->i_mapping);
1851
1852         devices = &root->fs_info->fs_devices->devices;
1853
1854         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1855         list_for_each_entry(device, devices, dev_list) {
1856                 if (device->bdev == bdev) {
1857                         ret = -EEXIST;
1858                         mutex_unlock(
1859                                 &root->fs_info->fs_devices->device_list_mutex);
1860                         goto error;
1861                 }
1862         }
1863         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1864
1865         device = kzalloc(sizeof(*device), GFP_NOFS);
1866         if (!device) {
1867                 /* we can safely leave the fs_devices entry around */
1868                 ret = -ENOMEM;
1869                 goto error;
1870         }
1871
1872         name = rcu_string_strdup(device_path, GFP_NOFS);
1873         if (!name) {
1874                 kfree(device);
1875                 ret = -ENOMEM;
1876                 goto error;
1877         }
1878         rcu_assign_pointer(device->name, name);
1879
1880         ret = find_next_devid(root, &device->devid);
1881         if (ret) {
1882                 rcu_string_free(device->name);
1883                 kfree(device);
1884                 goto error;
1885         }
1886
1887         trans = btrfs_start_transaction(root, 0);
1888         if (IS_ERR(trans)) {
1889                 rcu_string_free(device->name);
1890                 kfree(device);
1891                 ret = PTR_ERR(trans);
1892                 goto error;
1893         }
1894
1895         lock_chunks(root);
1896
1897         q = bdev_get_queue(bdev);
1898         if (blk_queue_discard(q))
1899                 device->can_discard = 1;
1900         device->writeable = 1;
1901         device->work.func = pending_bios_fn;
1902         generate_random_uuid(device->uuid);
1903         spin_lock_init(&device->io_lock);
1904         device->generation = trans->transid;
1905         device->io_width = root->sectorsize;
1906         device->io_align = root->sectorsize;
1907         device->sector_size = root->sectorsize;
1908         device->total_bytes = i_size_read(bdev->bd_inode);
1909         device->disk_total_bytes = device->total_bytes;
1910         device->dev_root = root->fs_info->dev_root;
1911         device->bdev = bdev;
1912         device->in_fs_metadata = 1;
1913         device->is_tgtdev_for_dev_replace = 0;
1914         device->mode = FMODE_EXCL;
1915         set_blocksize(device->bdev, 4096);
1916
1917         if (seeding_dev) {
1918                 sb->s_flags &= ~MS_RDONLY;
1919                 ret = btrfs_prepare_sprout(root);
1920                 BUG_ON(ret); /* -ENOMEM */
1921         }
1922
1923         device->fs_devices = root->fs_info->fs_devices;
1924
1925         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1926         list_add_rcu(&device->dev_list, &root->fs_info->fs_devices->devices);
1927         list_add(&device->dev_alloc_list,
1928                  &root->fs_info->fs_devices->alloc_list);
1929         root->fs_info->fs_devices->num_devices++;
1930         root->fs_info->fs_devices->open_devices++;
1931         root->fs_info->fs_devices->rw_devices++;
1932         root->fs_info->fs_devices->total_devices++;
1933         if (device->can_discard)
1934                 root->fs_info->fs_devices->num_can_discard++;
1935         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
1936
1937         spin_lock(&root->fs_info->free_chunk_lock);
1938         root->fs_info->free_chunk_space += device->total_bytes;
1939         spin_unlock(&root->fs_info->free_chunk_lock);
1940
1941         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
1942                 root->fs_info->fs_devices->rotating = 1;
1943
1944         total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
1945         btrfs_set_super_total_bytes(root->fs_info->super_copy,
1946                                     total_bytes + device->total_bytes);
1947
1948         total_bytes = btrfs_super_num_devices(root->fs_info->super_copy);
1949         btrfs_set_super_num_devices(root->fs_info->super_copy,
1950                                     total_bytes + 1);
1951         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1952
1953         if (seeding_dev) {
1954                 ret = init_first_rw_device(trans, root, device);
1955                 if (ret) {
1956                         btrfs_abort_transaction(trans, root, ret);
1957                         goto error_trans;
1958                 }
1959                 ret = btrfs_finish_sprout(trans, root);
1960                 if (ret) {
1961                         btrfs_abort_transaction(trans, root, ret);
1962                         goto error_trans;
1963                 }
1964         } else {
1965                 ret = btrfs_add_device(trans, root, device);
1966                 if (ret) {
1967                         btrfs_abort_transaction(trans, root, ret);
1968                         goto error_trans;
1969                 }
1970         }
1971
1972         /*
1973          * we've got more storage, clear any full flags on the space
1974          * infos
1975          */
1976         btrfs_clear_space_info_full(root->fs_info);
1977
1978         unlock_chunks(root);
1979         root->fs_info->num_tolerated_disk_barrier_failures =
1980                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1981         ret = btrfs_commit_transaction(trans, root);
1982
1983         if (seeding_dev) {
1984                 mutex_unlock(&uuid_mutex);
1985                 up_write(&sb->s_umount);
1986
1987                 if (ret) /* transaction commit */
1988                         return ret;
1989
1990                 ret = btrfs_relocate_sys_chunks(root);
1991                 if (ret < 0)
1992                         btrfs_error(root->fs_info, ret,
1993                                     "Failed to relocate sys chunks after "
1994                                     "device initialization. This can be fixed "
1995                                     "using the \"btrfs balance\" command.");
1996                 trans = btrfs_attach_transaction(root);
1997                 if (IS_ERR(trans)) {
1998                         if (PTR_ERR(trans) == -ENOENT)
1999                                 return 0;
2000                         return PTR_ERR(trans);
2001                 }
2002                 ret = btrfs_commit_transaction(trans, root);
2003         }
2004
2005         return ret;
2006
2007 error_trans:
2008         unlock_chunks(root);
2009         btrfs_end_transaction(trans, root);
2010         rcu_string_free(device->name);
2011         kfree(device);
2012 error:
2013         blkdev_put(bdev, FMODE_EXCL);
2014         if (seeding_dev) {
2015                 mutex_unlock(&uuid_mutex);
2016                 up_write(&sb->s_umount);
2017         }
2018         return ret;
2019 }
2020
2021 int btrfs_init_dev_replace_tgtdev(struct btrfs_root *root, char *device_path,
2022                                   struct btrfs_device **device_out)
2023 {
2024         struct request_queue *q;
2025         struct btrfs_device *device;
2026         struct block_device *bdev;
2027         struct btrfs_fs_info *fs_info = root->fs_info;
2028         struct list_head *devices;
2029         struct rcu_string *name;
2030         int ret = 0;
2031
2032         *device_out = NULL;
2033         if (fs_info->fs_devices->seeding)
2034                 return -EINVAL;
2035
2036         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
2037                                   fs_info->bdev_holder);
2038         if (IS_ERR(bdev))
2039                 return PTR_ERR(bdev);
2040
2041         filemap_write_and_wait(bdev->bd_inode->i_mapping);
2042
2043         devices = &fs_info->fs_devices->devices;
2044         list_for_each_entry(device, devices, dev_list) {
2045                 if (device->bdev == bdev) {
2046                         ret = -EEXIST;
2047                         goto error;
2048                 }
2049         }
2050
2051         device = kzalloc(sizeof(*device), GFP_NOFS);
2052         if (!device) {
2053                 ret = -ENOMEM;
2054                 goto error;
2055         }
2056
2057         name = rcu_string_strdup(device_path, GFP_NOFS);
2058         if (!name) {
2059                 kfree(device);
2060                 ret = -ENOMEM;
2061                 goto error;
2062         }
2063         rcu_assign_pointer(device->name, name);
2064
2065         q = bdev_get_queue(bdev);
2066         if (blk_queue_discard(q))
2067                 device->can_discard = 1;
2068         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2069         device->writeable = 1;
2070         device->work.func = pending_bios_fn;
2071         generate_random_uuid(device->uuid);
2072         device->devid = BTRFS_DEV_REPLACE_DEVID;
2073         spin_lock_init(&device->io_lock);
2074         device->generation = 0;
2075         device->io_width = root->sectorsize;
2076         device->io_align = root->sectorsize;
2077         device->sector_size = root->sectorsize;
2078         device->total_bytes = i_size_read(bdev->bd_inode);
2079         device->disk_total_bytes = device->total_bytes;
2080         device->dev_root = fs_info->dev_root;
2081         device->bdev = bdev;
2082         device->in_fs_metadata = 1;
2083         device->is_tgtdev_for_dev_replace = 1;
2084         device->mode = FMODE_EXCL;
2085         set_blocksize(device->bdev, 4096);
2086         device->fs_devices = fs_info->fs_devices;
2087         list_add(&device->dev_list, &fs_info->fs_devices->devices);
2088         fs_info->fs_devices->num_devices++;
2089         fs_info->fs_devices->open_devices++;
2090         if (device->can_discard)
2091                 fs_info->fs_devices->num_can_discard++;
2092         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2093
2094         *device_out = device;
2095         return ret;
2096
2097 error:
2098         blkdev_put(bdev, FMODE_EXCL);
2099         return ret;
2100 }
2101
2102 void btrfs_init_dev_replace_tgtdev_for_resume(struct btrfs_fs_info *fs_info,
2103                                               struct btrfs_device *tgtdev)
2104 {
2105         WARN_ON(fs_info->fs_devices->rw_devices == 0);
2106         tgtdev->io_width = fs_info->dev_root->sectorsize;
2107         tgtdev->io_align = fs_info->dev_root->sectorsize;
2108         tgtdev->sector_size = fs_info->dev_root->sectorsize;
2109         tgtdev->dev_root = fs_info->dev_root;
2110         tgtdev->in_fs_metadata = 1;
2111 }
2112
2113 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
2114                                         struct btrfs_device *device)
2115 {
2116         int ret;
2117         struct btrfs_path *path;
2118         struct btrfs_root *root;
2119         struct btrfs_dev_item *dev_item;
2120         struct extent_buffer *leaf;
2121         struct btrfs_key key;
2122
2123         root = device->dev_root->fs_info->chunk_root;
2124
2125         path = btrfs_alloc_path();
2126         if (!path)
2127                 return -ENOMEM;
2128
2129         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2130         key.type = BTRFS_DEV_ITEM_KEY;
2131         key.offset = device->devid;
2132
2133         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2134         if (ret < 0)
2135                 goto out;
2136
2137         if (ret > 0) {
2138                 ret = -ENOENT;
2139                 goto out;
2140         }
2141
2142         leaf = path->nodes[0];
2143         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
2144
2145         btrfs_set_device_id(leaf, dev_item, device->devid);
2146         btrfs_set_device_type(leaf, dev_item, device->type);
2147         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
2148         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
2149         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
2150         btrfs_set_device_total_bytes(leaf, dev_item, device->disk_total_bytes);
2151         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
2152         btrfs_mark_buffer_dirty(leaf);
2153
2154 out:
2155         btrfs_free_path(path);
2156         return ret;
2157 }
2158
2159 static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
2160                       struct btrfs_device *device, u64 new_size)
2161 {
2162         struct btrfs_super_block *super_copy =
2163                 device->dev_root->fs_info->super_copy;
2164         u64 old_total = btrfs_super_total_bytes(super_copy);
2165         u64 diff = new_size - device->total_bytes;
2166
2167         if (!device->writeable)
2168                 return -EACCES;
2169         if (new_size <= device->total_bytes ||
2170             device->is_tgtdev_for_dev_replace)
2171                 return -EINVAL;
2172
2173         btrfs_set_super_total_bytes(super_copy, old_total + diff);
2174         device->fs_devices->total_rw_bytes += diff;
2175
2176         device->total_bytes = new_size;
2177         device->disk_total_bytes = new_size;
2178         btrfs_clear_space_info_full(device->dev_root->fs_info);
2179
2180         return btrfs_update_device(trans, device);
2181 }
2182
2183 int btrfs_grow_device(struct btrfs_trans_handle *trans,
2184                       struct btrfs_device *device, u64 new_size)
2185 {
2186         int ret;
2187         lock_chunks(device->dev_root);
2188         ret = __btrfs_grow_device(trans, device, new_size);
2189         unlock_chunks(device->dev_root);
2190         return ret;
2191 }
2192
2193 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
2194                             struct btrfs_root *root,
2195                             u64 chunk_tree, u64 chunk_objectid,
2196                             u64 chunk_offset)
2197 {
2198         int ret;
2199         struct btrfs_path *path;
2200         struct btrfs_key key;
2201
2202         root = root->fs_info->chunk_root;
2203         path = btrfs_alloc_path();
2204         if (!path)
2205                 return -ENOMEM;
2206
2207         key.objectid = chunk_objectid;
2208         key.offset = chunk_offset;
2209         key.type = BTRFS_CHUNK_ITEM_KEY;
2210
2211         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2212         if (ret < 0)
2213                 goto out;
2214         else if (ret > 0) { /* Logic error or corruption */
2215                 btrfs_error(root->fs_info, -ENOENT,
2216                             "Failed lookup while freeing chunk.");
2217                 ret = -ENOENT;
2218                 goto out;
2219         }
2220
2221         ret = btrfs_del_item(trans, root, path);
2222         if (ret < 0)
2223                 btrfs_error(root->fs_info, ret,
2224                             "Failed to delete chunk item.");
2225 out:
2226         btrfs_free_path(path);
2227         return ret;
2228 }
2229
2230 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
2231                         chunk_offset)
2232 {
2233         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
2234         struct btrfs_disk_key *disk_key;
2235         struct btrfs_chunk *chunk;
2236         u8 *ptr;
2237         int ret = 0;
2238         u32 num_stripes;
2239         u32 array_size;
2240         u32 len = 0;
2241         u32 cur;
2242         struct btrfs_key key;
2243
2244         array_size = btrfs_super_sys_array_size(super_copy);
2245
2246         ptr = super_copy->sys_chunk_array;
2247         cur = 0;
2248
2249         while (cur < array_size) {
2250                 disk_key = (struct btrfs_disk_key *)ptr;
2251                 btrfs_disk_key_to_cpu(&key, disk_key);
2252
2253                 len = sizeof(*disk_key);
2254
2255                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
2256                         chunk = (struct btrfs_chunk *)(ptr + len);
2257                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
2258                         len += btrfs_chunk_item_size(num_stripes);
2259                 } else {
2260                         ret = -EIO;
2261                         break;
2262                 }
2263                 if (key.objectid == chunk_objectid &&
2264                     key.offset == chunk_offset) {
2265                         memmove(ptr, ptr + len, array_size - (cur + len));
2266                         array_size -= len;
2267                         btrfs_set_super_sys_array_size(super_copy, array_size);
2268                 } else {
2269                         ptr += len;
2270                         cur += len;
2271                 }
2272         }
2273         return ret;
2274 }
2275
2276 static int btrfs_relocate_chunk(struct btrfs_root *root,
2277                          u64 chunk_tree, u64 chunk_objectid,
2278                          u64 chunk_offset)
2279 {
2280         struct extent_map_tree *em_tree;
2281         struct btrfs_root *extent_root;
2282         struct btrfs_trans_handle *trans;
2283         struct extent_map *em;
2284         struct map_lookup *map;
2285         int ret;
2286         int i;
2287
2288         root = root->fs_info->chunk_root;
2289         extent_root = root->fs_info->extent_root;
2290         em_tree = &root->fs_info->mapping_tree.map_tree;
2291
2292         ret = btrfs_can_relocate(extent_root, chunk_offset);
2293         if (ret)
2294                 return -ENOSPC;
2295
2296         /* step one, relocate all the extents inside this chunk */
2297         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
2298         if (ret)
2299                 return ret;
2300
2301         trans = btrfs_start_transaction(root, 0);
2302         BUG_ON(IS_ERR(trans));
2303
2304         lock_chunks(root);
2305
2306         /*
2307          * step two, delete the device extents and the
2308          * chunk tree entries
2309          */
2310         read_lock(&em_tree->lock);
2311         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
2312         read_unlock(&em_tree->lock);
2313
2314         BUG_ON(!em || em->start > chunk_offset ||
2315                em->start + em->len < chunk_offset);
2316         map = (struct map_lookup *)em->bdev;
2317
2318         for (i = 0; i < map->num_stripes; i++) {
2319                 ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
2320                                             map->stripes[i].physical);
2321                 BUG_ON(ret);
2322
2323                 if (map->stripes[i].dev) {
2324                         ret = btrfs_update_device(trans, map->stripes[i].dev);
2325                         BUG_ON(ret);
2326                 }
2327         }
2328         ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
2329                                chunk_offset);
2330
2331         BUG_ON(ret);
2332
2333         trace_btrfs_chunk_free(root, map, chunk_offset, em->len);
2334
2335         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2336                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
2337                 BUG_ON(ret);
2338         }
2339
2340         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
2341         BUG_ON(ret);
2342
2343         write_lock(&em_tree->lock);
2344         remove_extent_mapping(em_tree, em);
2345         write_unlock(&em_tree->lock);
2346
2347         kfree(map);
2348         em->bdev = NULL;
2349
2350         /* once for the tree */
2351         free_extent_map(em);
2352         /* once for us */
2353         free_extent_map(em);
2354
2355         unlock_chunks(root);
2356         btrfs_end_transaction(trans, root);
2357         return 0;
2358 }
2359
2360 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
2361 {
2362         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
2363         struct btrfs_path *path;
2364         struct extent_buffer *leaf;
2365         struct btrfs_chunk *chunk;
2366         struct btrfs_key key;
2367         struct btrfs_key found_key;
2368         u64 chunk_tree = chunk_root->root_key.objectid;
2369         u64 chunk_type;
2370         bool retried = false;
2371         int failed = 0;
2372         int ret;
2373
2374         path = btrfs_alloc_path();
2375         if (!path)
2376                 return -ENOMEM;
2377
2378 again:
2379         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2380         key.offset = (u64)-1;
2381         key.type = BTRFS_CHUNK_ITEM_KEY;
2382
2383         while (1) {
2384                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2385                 if (ret < 0)
2386                         goto error;
2387                 BUG_ON(ret == 0); /* Corruption */
2388
2389                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
2390                                           key.type);
2391                 if (ret < 0)
2392                         goto error;
2393                 if (ret > 0)
2394                         break;
2395
2396                 leaf = path->nodes[0];
2397                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2398
2399                 chunk = btrfs_item_ptr(leaf, path->slots[0],
2400                                        struct btrfs_chunk);
2401                 chunk_type = btrfs_chunk_type(leaf, chunk);
2402                 btrfs_release_path(path);
2403
2404                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
2405                         ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
2406                                                    found_key.objectid,
2407                                                    found_key.offset);
2408                         if (ret == -ENOSPC)
2409                                 failed++;
2410                         else if (ret)
2411                                 BUG();
2412                 }
2413
2414                 if (found_key.offset == 0)
2415                         break;
2416                 key.offset = found_key.offset - 1;
2417         }
2418         ret = 0;
2419         if (failed && !retried) {
2420                 failed = 0;
2421                 retried = true;
2422                 goto again;
2423         } else if (failed && retried) {
2424                 WARN_ON(1);
2425                 ret = -ENOSPC;
2426         }
2427 error:
2428         btrfs_free_path(path);
2429         return ret;
2430 }
2431
2432 static int insert_balance_item(struct btrfs_root *root,
2433                                struct btrfs_balance_control *bctl)
2434 {
2435         struct btrfs_trans_handle *trans;
2436         struct btrfs_balance_item *item;
2437         struct btrfs_disk_balance_args disk_bargs;
2438         struct btrfs_path *path;
2439         struct extent_buffer *leaf;
2440         struct btrfs_key key;
2441         int ret, err;
2442
2443         path = btrfs_alloc_path();
2444         if (!path)
2445                 return -ENOMEM;
2446
2447         trans = btrfs_start_transaction(root, 0);
2448         if (IS_ERR(trans)) {
2449                 btrfs_free_path(path);
2450                 return PTR_ERR(trans);
2451         }
2452
2453         key.objectid = BTRFS_BALANCE_OBJECTID;
2454         key.type = BTRFS_BALANCE_ITEM_KEY;
2455         key.offset = 0;
2456
2457         ret = btrfs_insert_empty_item(trans, root, path, &key,
2458                                       sizeof(*item));
2459         if (ret)
2460                 goto out;
2461
2462         leaf = path->nodes[0];
2463         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
2464
2465         memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
2466
2467         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->data);
2468         btrfs_set_balance_data(leaf, item, &disk_bargs);
2469         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->meta);
2470         btrfs_set_balance_meta(leaf, item, &disk_bargs);
2471         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->sys);
2472         btrfs_set_balance_sys(leaf, item, &disk_bargs);
2473
2474         btrfs_set_balance_flags(leaf, item, bctl->flags);
2475
2476         btrfs_mark_buffer_dirty(leaf);
2477 out:
2478         btrfs_free_path(path);
2479         err = btrfs_commit_transaction(trans, root);
2480         if (err && !ret)
2481                 ret = err;
2482         return ret;
2483 }
2484
2485 static int del_balance_item(struct btrfs_root *root)
2486 {
2487         struct btrfs_trans_handle *trans;
2488         struct btrfs_path *path;
2489         struct btrfs_key key;
2490         int ret, err;
2491
2492         path = btrfs_alloc_path();
2493         if (!path)
2494                 return -ENOMEM;
2495
2496         trans = btrfs_start_transaction(root, 0);
2497         if (IS_ERR(trans)) {
2498                 btrfs_free_path(path);
2499                 return PTR_ERR(trans);
2500         }
2501
2502         key.objectid = BTRFS_BALANCE_OBJECTID;
2503         key.type = BTRFS_BALANCE_ITEM_KEY;
2504         key.offset = 0;
2505
2506         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2507         if (ret < 0)
2508                 goto out;
2509         if (ret > 0) {
2510                 ret = -ENOENT;
2511                 goto out;
2512         }
2513
2514         ret = btrfs_del_item(trans, root, path);
2515 out:
2516         btrfs_free_path(path);
2517         err = btrfs_commit_transaction(trans, root);
2518         if (err && !ret)
2519                 ret = err;
2520         return ret;
2521 }
2522
2523 /*
2524  * This is a heuristic used to reduce the number of chunks balanced on
2525  * resume after balance was interrupted.
2526  */
2527 static void update_balance_args(struct btrfs_balance_control *bctl)
2528 {
2529         /*
2530          * Turn on soft mode for chunk types that were being converted.
2531          */
2532         if (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)
2533                 bctl->data.flags |= BTRFS_BALANCE_ARGS_SOFT;
2534         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)
2535                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_SOFT;
2536         if (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)
2537                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_SOFT;
2538
2539         /*
2540          * Turn on usage filter if is not already used.  The idea is
2541          * that chunks that we have already balanced should be
2542          * reasonably full.  Don't do it for chunks that are being
2543          * converted - that will keep us from relocating unconverted
2544          * (albeit full) chunks.
2545          */
2546         if (!(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2547             !(bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2548                 bctl->data.flags |= BTRFS_BALANCE_ARGS_USAGE;
2549                 bctl->data.usage = 90;
2550         }
2551         if (!(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2552             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2553                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_USAGE;
2554                 bctl->sys.usage = 90;
2555         }
2556         if (!(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2557             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2558                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_USAGE;
2559                 bctl->meta.usage = 90;
2560         }
2561 }
2562
2563 /*
2564  * Should be called with both balance and volume mutexes held to
2565  * serialize other volume operations (add_dev/rm_dev/resize) with
2566  * restriper.  Same goes for unset_balance_control.
2567  */
2568 static void set_balance_control(struct btrfs_balance_control *bctl)
2569 {
2570         struct btrfs_fs_info *fs_info = bctl->fs_info;
2571
2572         BUG_ON(fs_info->balance_ctl);
2573
2574         spin_lock(&fs_info->balance_lock);
2575         fs_info->balance_ctl = bctl;
2576         spin_unlock(&fs_info->balance_lock);
2577 }
2578
2579 static void unset_balance_control(struct btrfs_fs_info *fs_info)
2580 {
2581         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2582
2583         BUG_ON(!fs_info->balance_ctl);
2584
2585         spin_lock(&fs_info->balance_lock);
2586         fs_info->balance_ctl = NULL;
2587         spin_unlock(&fs_info->balance_lock);
2588
2589         kfree(bctl);
2590 }
2591
2592 /*
2593  * Balance filters.  Return 1 if chunk should be filtered out
2594  * (should not be balanced).
2595  */
2596 static int chunk_profiles_filter(u64 chunk_type,
2597                                  struct btrfs_balance_args *bargs)
2598 {
2599         chunk_type = chunk_to_extended(chunk_type) &
2600                                 BTRFS_EXTENDED_PROFILE_MASK;
2601
2602         if (bargs->profiles & chunk_type)
2603                 return 0;
2604
2605         return 1;
2606 }
2607
2608 static int chunk_usage_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
2609                               struct btrfs_balance_args *bargs)
2610 {
2611         struct btrfs_block_group_cache *cache;
2612         u64 chunk_used, user_thresh;
2613         int ret = 1;
2614
2615         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
2616         chunk_used = btrfs_block_group_used(&cache->item);
2617
2618         if (bargs->usage == 0)
2619                 user_thresh = 0;
2620         else if (bargs->usage > 100)
2621                 user_thresh = cache->key.offset;
2622         else
2623                 user_thresh = div_factor_fine(cache->key.offset,
2624                                               bargs->usage);
2625
2626         if (chunk_used < user_thresh)
2627                 ret = 0;
2628
2629         btrfs_put_block_group(cache);
2630         return ret;
2631 }
2632
2633 static int chunk_devid_filter(struct extent_buffer *leaf,
2634                               struct btrfs_chunk *chunk,
2635                               struct btrfs_balance_args *bargs)
2636 {
2637         struct btrfs_stripe *stripe;
2638         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2639         int i;
2640
2641         for (i = 0; i < num_stripes; i++) {
2642                 stripe = btrfs_stripe_nr(chunk, i);
2643                 if (btrfs_stripe_devid(leaf, stripe) == bargs->devid)
2644                         return 0;
2645         }
2646
2647         return 1;
2648 }
2649
2650 /* [pstart, pend) */
2651 static int chunk_drange_filter(struct extent_buffer *leaf,
2652                                struct btrfs_chunk *chunk,
2653                                u64 chunk_offset,
2654                                struct btrfs_balance_args *bargs)
2655 {
2656         struct btrfs_stripe *stripe;
2657         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2658         u64 stripe_offset;
2659         u64 stripe_length;
2660         int factor;
2661         int i;
2662
2663         if (!(bargs->flags & BTRFS_BALANCE_ARGS_DEVID))
2664                 return 0;
2665
2666         if (btrfs_chunk_type(leaf, chunk) & (BTRFS_BLOCK_GROUP_DUP |
2667              BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10))
2668                 factor = 2;
2669         else
2670                 factor = 1;
2671         factor = num_stripes / factor;
2672
2673         for (i = 0; i < num_stripes; i++) {
2674                 stripe = btrfs_stripe_nr(chunk, i);
2675                 if (btrfs_stripe_devid(leaf, stripe) != bargs->devid)
2676                         continue;
2677
2678                 stripe_offset = btrfs_stripe_offset(leaf, stripe);
2679                 stripe_length = btrfs_chunk_length(leaf, chunk);
2680                 do_div(stripe_length, factor);
2681
2682                 if (stripe_offset < bargs->pend &&
2683                     stripe_offset + stripe_length > bargs->pstart)
2684                         return 0;
2685         }
2686
2687         return 1;
2688 }
2689
2690 /* [vstart, vend) */
2691 static int chunk_vrange_filter(struct extent_buffer *leaf,
2692                                struct btrfs_chunk *chunk,
2693                                u64 chunk_offset,
2694                                struct btrfs_balance_args *bargs)
2695 {
2696         if (chunk_offset < bargs->vend &&
2697             chunk_offset + btrfs_chunk_length(leaf, chunk) > bargs->vstart)
2698                 /* at least part of the chunk is inside this vrange */
2699                 return 0;
2700
2701         return 1;
2702 }
2703
2704 static int chunk_soft_convert_filter(u64 chunk_type,
2705                                      struct btrfs_balance_args *bargs)
2706 {
2707         if (!(bargs->flags & BTRFS_BALANCE_ARGS_CONVERT))
2708                 return 0;
2709
2710         chunk_type = chunk_to_extended(chunk_type) &
2711                                 BTRFS_EXTENDED_PROFILE_MASK;
2712
2713         if (bargs->target == chunk_type)
2714                 return 1;
2715
2716         return 0;
2717 }
2718
2719 static int should_balance_chunk(struct btrfs_root *root,
2720                                 struct extent_buffer *leaf,
2721                                 struct btrfs_chunk *chunk, u64 chunk_offset)
2722 {
2723         struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
2724         struct btrfs_balance_args *bargs = NULL;
2725         u64 chunk_type = btrfs_chunk_type(leaf, chunk);
2726
2727         /* type filter */
2728         if (!((chunk_type & BTRFS_BLOCK_GROUP_TYPE_MASK) &
2729               (bctl->flags & BTRFS_BALANCE_TYPE_MASK))) {
2730                 return 0;
2731         }
2732
2733         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
2734                 bargs = &bctl->data;
2735         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
2736                 bargs = &bctl->sys;
2737         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
2738                 bargs = &bctl->meta;
2739
2740         /* profiles filter */
2741         if ((bargs->flags & BTRFS_BALANCE_ARGS_PROFILES) &&
2742             chunk_profiles_filter(chunk_type, bargs)) {
2743                 return 0;
2744         }
2745
2746         /* usage filter */
2747         if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
2748             chunk_usage_filter(bctl->fs_info, chunk_offset, bargs)) {
2749                 return 0;
2750         }
2751
2752         /* devid filter */
2753         if ((bargs->flags & BTRFS_BALANCE_ARGS_DEVID) &&
2754             chunk_devid_filter(leaf, chunk, bargs)) {
2755                 return 0;
2756         }
2757
2758         /* drange filter, makes sense only with devid filter */
2759         if ((bargs->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
2760             chunk_drange_filter(leaf, chunk, chunk_offset, bargs)) {
2761                 return 0;
2762         }
2763
2764         /* vrange filter */
2765         if ((bargs->flags & BTRFS_BALANCE_ARGS_VRANGE) &&
2766             chunk_vrange_filter(leaf, chunk, chunk_offset, bargs)) {
2767                 return 0;
2768         }
2769
2770         /* soft profile changing mode */
2771         if ((bargs->flags & BTRFS_BALANCE_ARGS_SOFT) &&
2772             chunk_soft_convert_filter(chunk_type, bargs)) {
2773                 return 0;
2774         }
2775
2776         return 1;
2777 }
2778
2779 static int __btrfs_balance(struct btrfs_fs_info *fs_info)
2780 {
2781         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2782         struct btrfs_root *chunk_root = fs_info->chunk_root;
2783         struct btrfs_root *dev_root = fs_info->dev_root;
2784         struct list_head *devices;
2785         struct btrfs_device *device;
2786         u64 old_size;
2787         u64 size_to_free;
2788         struct btrfs_chunk *chunk;
2789         struct btrfs_path *path;
2790         struct btrfs_key key;
2791         struct btrfs_key found_key;
2792         struct btrfs_trans_handle *trans;
2793         struct extent_buffer *leaf;
2794         int slot;
2795         int ret;
2796         int enospc_errors = 0;
2797         bool counting = true;
2798
2799         /* step one make some room on all the devices */
2800         devices = &fs_info->fs_devices->devices;
2801         list_for_each_entry(device, devices, dev_list) {
2802                 old_size = device->total_bytes;
2803                 size_to_free = div_factor(old_size, 1);
2804                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
2805                 if (!device->writeable ||
2806                     device->total_bytes - device->bytes_used > size_to_free ||
2807                     device->is_tgtdev_for_dev_replace)
2808                         continue;
2809
2810                 ret = btrfs_shrink_device(device, old_size - size_to_free);
2811                 if (ret == -ENOSPC)
2812                         break;
2813                 BUG_ON(ret);
2814
2815                 trans = btrfs_start_transaction(dev_root, 0);
2816                 BUG_ON(IS_ERR(trans));
2817
2818                 ret = btrfs_grow_device(trans, device, old_size);
2819                 BUG_ON(ret);
2820
2821                 btrfs_end_transaction(trans, dev_root);
2822         }
2823
2824         /* step two, relocate all the chunks */
2825         path = btrfs_alloc_path();
2826         if (!path) {
2827                 ret = -ENOMEM;
2828                 goto error;
2829         }
2830
2831         /* zero out stat counters */
2832         spin_lock(&fs_info->balance_lock);
2833         memset(&bctl->stat, 0, sizeof(bctl->stat));
2834         spin_unlock(&fs_info->balance_lock);
2835 again:
2836         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2837         key.offset = (u64)-1;
2838         key.type = BTRFS_CHUNK_ITEM_KEY;
2839
2840         while (1) {
2841                 if ((!counting && atomic_read(&fs_info->balance_pause_req)) ||
2842                     atomic_read(&fs_info->balance_cancel_req)) {
2843                         ret = -ECANCELED;
2844                         goto error;
2845                 }
2846
2847                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2848                 if (ret < 0)
2849                         goto error;
2850
2851                 /*
2852                  * this shouldn't happen, it means the last relocate
2853                  * failed
2854                  */
2855                 if (ret == 0)
2856                         BUG(); /* FIXME break ? */
2857
2858                 ret = btrfs_previous_item(chunk_root, path, 0,
2859                                           BTRFS_CHUNK_ITEM_KEY);
2860                 if (ret) {
2861                         ret = 0;
2862                         break;
2863                 }
2864
2865                 leaf = path->nodes[0];
2866                 slot = path->slots[0];
2867                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2868
2869                 if (found_key.objectid != key.objectid)
2870                         break;
2871
2872                 /* chunk zero is special */
2873                 if (found_key.offset == 0)
2874                         break;
2875
2876                 chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
2877
2878                 if (!counting) {
2879                         spin_lock(&fs_info->balance_lock);
2880                         bctl->stat.considered++;
2881                         spin_unlock(&fs_info->balance_lock);
2882                 }
2883
2884                 ret = should_balance_chunk(chunk_root, leaf, chunk,
2885                                            found_key.offset);
2886                 btrfs_release_path(path);
2887                 if (!ret)
2888                         goto loop;
2889
2890                 if (counting) {
2891                         spin_lock(&fs_info->balance_lock);
2892                         bctl->stat.expected++;
2893                         spin_unlock(&fs_info->balance_lock);
2894                         goto loop;
2895                 }
2896
2897                 ret = btrfs_relocate_chunk(chunk_root,
2898                                            chunk_root->root_key.objectid,
2899                                            found_key.objectid,
2900                                            found_key.offset);
2901                 if (ret && ret != -ENOSPC)
2902                         goto error;
2903                 if (ret == -ENOSPC) {
2904                         enospc_errors++;
2905                 } else {
2906                         spin_lock(&fs_info->balance_lock);
2907                         bctl->stat.completed++;
2908                         spin_unlock(&fs_info->balance_lock);
2909                 }
2910 loop:
2911                 key.offset = found_key.offset - 1;
2912         }
2913
2914         if (counting) {
2915                 btrfs_release_path(path);
2916                 counting = false;
2917                 goto again;
2918         }
2919 error:
2920         btrfs_free_path(path);
2921         if (enospc_errors) {
2922                 printk(KERN_INFO "btrfs: %d enospc errors during balance\n",
2923                        enospc_errors);
2924                 if (!ret)
2925                         ret = -ENOSPC;
2926         }
2927
2928         return ret;
2929 }
2930
2931 /**
2932  * alloc_profile_is_valid - see if a given profile is valid and reduced
2933  * @flags: profile to validate
2934  * @extended: if true @flags is treated as an extended profile
2935  */
2936 static int alloc_profile_is_valid(u64 flags, int extended)
2937 {
2938         u64 mask = (extended ? BTRFS_EXTENDED_PROFILE_MASK :
2939                                BTRFS_BLOCK_GROUP_PROFILE_MASK);
2940
2941         flags &= ~BTRFS_BLOCK_GROUP_TYPE_MASK;
2942
2943         /* 1) check that all other bits are zeroed */
2944         if (flags & ~mask)
2945                 return 0;
2946
2947         /* 2) see if profile is reduced */
2948         if (flags == 0)
2949                 return !extended; /* "0" is valid for usual profiles */
2950
2951         /* true if exactly one bit set */
2952         return (flags & (flags - 1)) == 0;
2953 }
2954
2955 static inline int balance_need_close(struct btrfs_fs_info *fs_info)
2956 {
2957         /* cancel requested || normal exit path */
2958         return atomic_read(&fs_info->balance_cancel_req) ||
2959                 (atomic_read(&fs_info->balance_pause_req) == 0 &&
2960                  atomic_read(&fs_info->balance_cancel_req) == 0);
2961 }
2962
2963 static void __cancel_balance(struct btrfs_fs_info *fs_info)
2964 {
2965         int ret;
2966
2967         unset_balance_control(fs_info);
2968         ret = del_balance_item(fs_info->tree_root);
2969         BUG_ON(ret);
2970
2971         atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
2972 }
2973
2974 void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
2975                                struct btrfs_ioctl_balance_args *bargs);
2976
2977 /*
2978  * Should be called with both balance and volume mutexes held
2979  */
2980 int btrfs_balance(struct btrfs_balance_control *bctl,
2981                   struct btrfs_ioctl_balance_args *bargs)
2982 {
2983         struct btrfs_fs_info *fs_info = bctl->fs_info;
2984         u64 allowed;
2985         int mixed = 0;
2986         int ret;
2987         u64 num_devices;
2988
2989         if (btrfs_fs_closing(fs_info) ||
2990             atomic_read(&fs_info->balance_pause_req) ||
2991             atomic_read(&fs_info->balance_cancel_req)) {
2992                 ret = -EINVAL;
2993                 goto out;
2994         }
2995
2996         allowed = btrfs_super_incompat_flags(fs_info->super_copy);
2997         if (allowed & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
2998                 mixed = 1;
2999
3000         /*
3001          * In case of mixed groups both data and meta should be picked,
3002          * and identical options should be given for both of them.
3003          */
3004         allowed = BTRFS_BALANCE_DATA | BTRFS_BALANCE_METADATA;
3005         if (mixed && (bctl->flags & allowed)) {
3006                 if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
3007                     !(bctl->flags & BTRFS_BALANCE_METADATA) ||
3008                     memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
3009                         printk(KERN_ERR "btrfs: with mixed groups data and "
3010                                "metadata balance options must be the same\n");
3011                         ret = -EINVAL;
3012                         goto out;
3013                 }
3014         }
3015
3016         num_devices = fs_info->fs_devices->num_devices;
3017         btrfs_dev_replace_lock(&fs_info->dev_replace);
3018         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) {
3019                 BUG_ON(num_devices < 1);
3020                 num_devices--;
3021         }
3022         btrfs_dev_replace_unlock(&fs_info->dev_replace);
3023         allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
3024         if (num_devices == 1)
3025                 allowed |= BTRFS_BLOCK_GROUP_DUP;
3026         else if (num_devices < 4)
3027                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1);
3028         else
3029                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
3030                                 BTRFS_BLOCK_GROUP_RAID10);
3031
3032         if ((bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3033             (!alloc_profile_is_valid(bctl->data.target, 1) ||
3034              (bctl->data.target & ~allowed))) {
3035                 printk(KERN_ERR "btrfs: unable to start balance with target "
3036                        "data profile %llu\n",
3037                        (unsigned long long)bctl->data.target);
3038                 ret = -EINVAL;
3039                 goto out;
3040         }
3041         if ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3042             (!alloc_profile_is_valid(bctl->meta.target, 1) ||
3043              (bctl->meta.target & ~allowed))) {
3044                 printk(KERN_ERR "btrfs: unable to start balance with target "
3045                        "metadata profile %llu\n",
3046                        (unsigned long long)bctl->meta.target);
3047                 ret = -EINVAL;
3048                 goto out;
3049         }
3050         if ((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3051             (!alloc_profile_is_valid(bctl->sys.target, 1) ||
3052              (bctl->sys.target & ~allowed))) {
3053                 printk(KERN_ERR "btrfs: unable to start balance with target "
3054                        "system profile %llu\n",
3055                        (unsigned long long)bctl->sys.target);
3056                 ret = -EINVAL;
3057                 goto out;
3058         }
3059
3060         /* allow dup'ed data chunks only in mixed mode */
3061         if (!mixed && (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3062             (bctl->data.target & BTRFS_BLOCK_GROUP_DUP)) {
3063                 printk(KERN_ERR "btrfs: dup for data is not allowed\n");
3064                 ret = -EINVAL;
3065                 goto out;
3066         }
3067
3068         /* allow to reduce meta or sys integrity only if force set */
3069         allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3070                         BTRFS_BLOCK_GROUP_RAID10;
3071         if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3072              (fs_info->avail_system_alloc_bits & allowed) &&
3073              !(bctl->sys.target & allowed)) ||
3074             ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3075              (fs_info->avail_metadata_alloc_bits & allowed) &&
3076              !(bctl->meta.target & allowed))) {
3077                 if (bctl->flags & BTRFS_BALANCE_FORCE) {
3078                         printk(KERN_INFO "btrfs: force reducing metadata "
3079                                "integrity\n");
3080                 } else {
3081                         printk(KERN_ERR "btrfs: balance will reduce metadata "
3082                                "integrity, use force if you want this\n");
3083                         ret = -EINVAL;
3084                         goto out;
3085                 }
3086         }
3087
3088         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3089                 int num_tolerated_disk_barrier_failures;
3090                 u64 target = bctl->sys.target;
3091
3092                 num_tolerated_disk_barrier_failures =
3093                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
3094                 if (num_tolerated_disk_barrier_failures > 0 &&
3095                     (target &
3096                      (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3097                       BTRFS_AVAIL_ALLOC_BIT_SINGLE)))
3098                         num_tolerated_disk_barrier_failures = 0;
3099                 else if (num_tolerated_disk_barrier_failures > 1 &&
3100                          (target &
3101                           (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)))
3102                         num_tolerated_disk_barrier_failures = 1;
3103
3104                 fs_info->num_tolerated_disk_barrier_failures =
3105                         num_tolerated_disk_barrier_failures;
3106         }
3107
3108         ret = insert_balance_item(fs_info->tree_root, bctl);
3109         if (ret && ret != -EEXIST)
3110                 goto out;
3111
3112         if (!(bctl->flags & BTRFS_BALANCE_RESUME)) {
3113                 BUG_ON(ret == -EEXIST);
3114                 set_balance_control(bctl);
3115         } else {
3116                 BUG_ON(ret != -EEXIST);
3117                 spin_lock(&fs_info->balance_lock);
3118                 update_balance_args(bctl);
3119                 spin_unlock(&fs_info->balance_lock);
3120         }
3121
3122         atomic_inc(&fs_info->balance_running);
3123         mutex_unlock(&fs_info->balance_mutex);
3124
3125         ret = __btrfs_balance(fs_info);
3126
3127         mutex_lock(&fs_info->balance_mutex);
3128         atomic_dec(&fs_info->balance_running);
3129
3130         if (bargs) {
3131                 memset(bargs, 0, sizeof(*bargs));
3132                 update_ioctl_balance_args(fs_info, 0, bargs);
3133         }
3134
3135         if ((ret && ret != -ECANCELED && ret != -ENOSPC) ||
3136             balance_need_close(fs_info)) {
3137                 __cancel_balance(fs_info);
3138         }
3139
3140         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3141                 fs_info->num_tolerated_disk_barrier_failures =
3142                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
3143         }
3144
3145         wake_up(&fs_info->balance_wait_q);
3146
3147         return ret;
3148 out:
3149         if (bctl->flags & BTRFS_BALANCE_RESUME)
3150                 __cancel_balance(fs_info);
3151         else {
3152                 kfree(bctl);
3153                 atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3154         }
3155         return ret;
3156 }
3157
3158 static int balance_kthread(void *data)
3159 {
3160         struct btrfs_fs_info *fs_info = data;
3161         int ret = 0;
3162
3163         mutex_lock(&fs_info->volume_mutex);
3164         mutex_lock(&fs_info->balance_mutex);
3165
3166         if (fs_info->balance_ctl) {
3167                 printk(KERN_INFO "btrfs: continuing balance\n");
3168                 ret = btrfs_balance(fs_info->balance_ctl, NULL);
3169         }
3170
3171         mutex_unlock(&fs_info->balance_mutex);
3172         mutex_unlock(&fs_info->volume_mutex);
3173
3174         return ret;
3175 }
3176
3177 int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
3178 {
3179         struct task_struct *tsk;
3180
3181         spin_lock(&fs_info->balance_lock);
3182         if (!fs_info->balance_ctl) {
3183                 spin_unlock(&fs_info->balance_lock);
3184                 return 0;
3185         }
3186         spin_unlock(&fs_info->balance_lock);
3187
3188         if (btrfs_test_opt(fs_info->tree_root, SKIP_BALANCE)) {
3189                 printk(KERN_INFO "btrfs: force skipping balance\n");
3190                 return 0;
3191         }
3192
3193         tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance");
3194         if (IS_ERR(tsk))
3195                 return PTR_ERR(tsk);
3196
3197         return 0;
3198 }
3199
3200 int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
3201 {
3202         struct btrfs_balance_control *bctl;
3203         struct btrfs_balance_item *item;
3204         struct btrfs_disk_balance_args disk_bargs;
3205         struct btrfs_path *path;
3206         struct extent_buffer *leaf;
3207         struct btrfs_key key;
3208         int ret;
3209
3210         path = btrfs_alloc_path();
3211         if (!path)
3212                 return -ENOMEM;
3213
3214         key.objectid = BTRFS_BALANCE_OBJECTID;
3215         key.type = BTRFS_BALANCE_ITEM_KEY;
3216         key.offset = 0;
3217
3218         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
3219         if (ret < 0)
3220                 goto out;
3221         if (ret > 0) { /* ret = -ENOENT; */
3222                 ret = 0;
3223                 goto out;
3224         }
3225
3226         bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
3227         if (!bctl) {
3228                 ret = -ENOMEM;
3229                 goto out;
3230         }
3231
3232         leaf = path->nodes[0];
3233         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
3234
3235         bctl->fs_info = fs_info;
3236         bctl->flags = btrfs_balance_flags(leaf, item);
3237         bctl->flags |= BTRFS_BALANCE_RESUME;
3238
3239         btrfs_balance_data(leaf, item, &disk_bargs);
3240         btrfs_disk_balance_args_to_cpu(&bctl->data, &disk_bargs);
3241         btrfs_balance_meta(leaf, item, &disk_bargs);
3242         btrfs_disk_balance_args_to_cpu(&bctl->meta, &disk_bargs);
3243         btrfs_balance_sys(leaf, item, &disk_bargs);
3244         btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
3245
3246         WARN_ON(atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1));
3247
3248         mutex_lock(&fs_info->volume_mutex);
3249         mutex_lock(&fs_info->balance_mutex);
3250
3251         set_balance_control(bctl);
3252
3253         mutex_unlock(&fs_info->balance_mutex);
3254         mutex_unlock(&fs_info->volume_mutex);
3255 out:
3256         btrfs_free_path(path);
3257         return ret;
3258 }
3259
3260 int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
3261 {
3262         int ret = 0;
3263
3264         mutex_lock(&fs_info->balance_mutex);
3265         if (!fs_info->balance_ctl) {
3266                 mutex_unlock(&fs_info->balance_mutex);
3267                 return -ENOTCONN;
3268         }
3269
3270         if (atomic_read(&fs_info->balance_running)) {
3271                 atomic_inc(&fs_info->balance_pause_req);
3272                 mutex_unlock(&fs_info->balance_mutex);
3273
3274                 wait_event(fs_info->balance_wait_q,
3275                            atomic_read(&fs_info->balance_running) == 0);
3276
3277                 mutex_lock(&fs_info->balance_mutex);
3278                 /* we are good with balance_ctl ripped off from under us */
3279                 BUG_ON(atomic_read(&fs_info->balance_running));
3280                 atomic_dec(&fs_info->balance_pause_req);
3281         } else {
3282                 ret = -ENOTCONN;
3283         }
3284
3285         mutex_unlock(&fs_info->balance_mutex);
3286         return ret;
3287 }
3288
3289 int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
3290 {
3291         mutex_lock(&fs_info->balance_mutex);
3292         if (!fs_info->balance_ctl) {
3293                 mutex_unlock(&fs_info->balance_mutex);
3294                 return -ENOTCONN;
3295         }
3296
3297         atomic_inc(&fs_info->balance_cancel_req);
3298         /*
3299          * if we are running just wait and return, balance item is
3300          * deleted in btrfs_balance in this case
3301          */
3302         if (atomic_read(&fs_info->balance_running)) {
3303                 mutex_unlock(&fs_info->balance_mutex);
3304                 wait_event(fs_info->balance_wait_q,
3305                            atomic_read(&fs_info->balance_running) == 0);
3306                 mutex_lock(&fs_info->balance_mutex);
3307         } else {
3308                 /* __cancel_balance needs volume_mutex */
3309                 mutex_unlock(&fs_info->balance_mutex);
3310                 mutex_lock(&fs_info->volume_mutex);
3311                 mutex_lock(&fs_info->balance_mutex);
3312
3313                 if (fs_info->balance_ctl)
3314                         __cancel_balance(fs_info);
3315
3316                 mutex_unlock(&fs_info->volume_mutex);
3317         }
3318
3319         BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));
3320         atomic_dec(&fs_info->balance_cancel_req);
3321         mutex_unlock(&fs_info->balance_mutex);
3322         return 0;
3323 }
3324
3325 /*
3326  * shrinking a device means finding all of the device extents past
3327  * the new size, and then following the back refs to the chunks.
3328  * The chunk relocation code actually frees the device extent
3329  */
3330 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
3331 {
3332         struct btrfs_trans_handle *trans;
3333         struct btrfs_root *root = device->dev_root;
3334         struct btrfs_dev_extent *dev_extent = NULL;
3335         struct btrfs_path *path;
3336         u64 length;
3337         u64 chunk_tree;
3338         u64 chunk_objectid;
3339         u64 chunk_offset;
3340         int ret;
3341         int slot;
3342         int failed = 0;
3343         bool retried = false;
3344         struct extent_buffer *l;
3345         struct btrfs_key key;
3346         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3347         u64 old_total = btrfs_super_total_bytes(super_copy);
3348         u64 old_size = device->total_bytes;
3349         u64 diff = device->total_bytes - new_size;
3350
3351         if (device->is_tgtdev_for_dev_replace)
3352                 return -EINVAL;
3353
3354         path = btrfs_alloc_path();
3355         if (!path)
3356                 return -ENOMEM;
3357
3358         path->reada = 2;
3359
3360         lock_chunks(root);
3361
3362         device->total_bytes = new_size;
3363         if (device->writeable) {
3364                 device->fs_devices->total_rw_bytes -= diff;
3365                 spin_lock(&root->fs_info->free_chunk_lock);
3366                 root->fs_info->free_chunk_space -= diff;
3367                 spin_unlock(&root->fs_info->free_chunk_lock);
3368         }
3369         unlock_chunks(root);
3370
3371 again:
3372         key.objectid = device->devid;
3373         key.offset = (u64)-1;
3374         key.type = BTRFS_DEV_EXTENT_KEY;
3375
3376         do {
3377                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3378                 if (ret < 0)
3379                         goto done;
3380
3381                 ret = btrfs_previous_item(root, path, 0, key.type);
3382                 if (ret < 0)
3383                         goto done;
3384                 if (ret) {
3385                         ret = 0;
3386                         btrfs_release_path(path);
3387                         break;
3388                 }
3389
3390                 l = path->nodes[0];
3391                 slot = path->slots[0];
3392                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
3393
3394                 if (key.objectid != device->devid) {
3395                         btrfs_release_path(path);
3396                         break;
3397                 }
3398
3399                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
3400                 length = btrfs_dev_extent_length(l, dev_extent);
3401
3402                 if (key.offset + length <= new_size) {
3403                         btrfs_release_path(path);
3404                         break;
3405                 }
3406
3407                 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
3408                 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
3409                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
3410                 btrfs_release_path(path);
3411
3412                 ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
3413                                            chunk_offset);
3414                 if (ret && ret != -ENOSPC)
3415                         goto done;
3416                 if (ret == -ENOSPC)
3417                         failed++;
3418         } while (key.offset-- > 0);
3419
3420         if (failed && !retried) {
3421                 failed = 0;
3422                 retried = true;
3423                 goto again;
3424         } else if (failed && retried) {
3425                 ret = -ENOSPC;
3426                 lock_chunks(root);
3427
3428                 device->total_bytes = old_size;
3429                 if (device->writeable)
3430                         device->fs_devices->total_rw_bytes += diff;
3431                 spin_lock(&root->fs_info->free_chunk_lock);
3432                 root->fs_info->free_chunk_space += diff;
3433                 spin_unlock(&root->fs_info->free_chunk_lock);
3434                 unlock_chunks(root);
3435                 goto done;
3436         }
3437
3438         /* Shrinking succeeded, else we would be at "done". */
3439         trans = btrfs_start_transaction(root, 0);
3440         if (IS_ERR(trans)) {
3441                 ret = PTR_ERR(trans);
3442                 goto done;
3443         }
3444
3445         lock_chunks(root);
3446
3447         device->disk_total_bytes = new_size;
3448         /* Now btrfs_update_device() will change the on-disk size. */
3449         ret = btrfs_update_device(trans, device);
3450         if (ret) {
3451                 unlock_chunks(root);
3452                 btrfs_end_transaction(trans, root);
3453                 goto done;
3454         }
3455         WARN_ON(diff > old_total);
3456         btrfs_set_super_total_bytes(super_copy, old_total - diff);
3457         unlock_chunks(root);
3458         btrfs_end_transaction(trans, root);
3459 done:
3460         btrfs_free_path(path);
3461         return ret;
3462 }
3463
3464 static int btrfs_add_system_chunk(struct btrfs_root *root,
3465                            struct btrfs_key *key,
3466                            struct btrfs_chunk *chunk, int item_size)
3467 {
3468         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3469         struct btrfs_disk_key disk_key;
3470         u32 array_size;
3471         u8 *ptr;
3472
3473         array_size = btrfs_super_sys_array_size(super_copy);
3474         if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
3475                 return -EFBIG;
3476
3477         ptr = super_copy->sys_chunk_array + array_size;
3478         btrfs_cpu_key_to_disk(&disk_key, key);
3479         memcpy(ptr, &disk_key, sizeof(disk_key));
3480         ptr += sizeof(disk_key);
3481         memcpy(ptr, chunk, item_size);
3482         item_size += sizeof(disk_key);
3483         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
3484         return 0;
3485 }
3486
3487 /*
3488  * sort the devices in descending order by max_avail, total_avail
3489  */
3490 static int btrfs_cmp_device_info(const void *a, const void *b)
3491 {
3492         const struct btrfs_device_info *di_a = a;
3493         const struct btrfs_device_info *di_b = b;
3494
3495         if (di_a->max_avail > di_b->max_avail)
3496                 return -1;
3497         if (di_a->max_avail < di_b->max_avail)
3498                 return 1;
3499         if (di_a->total_avail > di_b->total_avail)
3500                 return -1;
3501         if (di_a->total_avail < di_b->total_avail)
3502                 return 1;
3503         return 0;
3504 }
3505
3506 struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
3507         { 2, 1, 0, 4, 2, 2 /* raid10 */ },
3508         { 1, 1, 2, 2, 2, 2 /* raid1 */ },
3509         { 1, 2, 1, 1, 1, 2 /* dup */ },
3510         { 1, 1, 0, 2, 1, 1 /* raid0 */ },
3511         { 1, 1, 1, 1, 1, 1 /* single */ },
3512 };
3513
3514 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
3515                                struct btrfs_root *extent_root,
3516                                struct map_lookup **map_ret,
3517                                u64 *num_bytes_out, u64 *stripe_size_out,
3518                                u64 start, u64 type)
3519 {
3520         struct btrfs_fs_info *info = extent_root->fs_info;
3521         struct btrfs_fs_devices *fs_devices = info->fs_devices;
3522         struct list_head *cur;
3523         struct map_lookup *map = NULL;
3524         struct extent_map_tree *em_tree;
3525         struct extent_map *em;
3526         struct btrfs_device_info *devices_info = NULL;
3527         u64 total_avail;
3528         int num_stripes;        /* total number of stripes to allocate */
3529         int sub_stripes;        /* sub_stripes info for map */
3530         int dev_stripes;        /* stripes per dev */
3531         int devs_max;           /* max devs to use */
3532         int devs_min;           /* min devs needed */
3533         int devs_increment;     /* ndevs has to be a multiple of this */
3534         int ncopies;            /* how many copies to data has */
3535         int ret;
3536         u64 max_stripe_size;
3537         u64 max_chunk_size;
3538         u64 stripe_size;
3539         u64 num_bytes;
3540         int ndevs;
3541         int i;
3542         int j;
3543         int index;
3544
3545         BUG_ON(!alloc_profile_is_valid(type, 0));
3546
3547         if (list_empty(&fs_devices->alloc_list))
3548                 return -ENOSPC;
3549
3550         index = __get_raid_index(type);
3551
3552         sub_stripes = btrfs_raid_array[index].sub_stripes;
3553         dev_stripes = btrfs_raid_array[index].dev_stripes;
3554         devs_max = btrfs_raid_array[index].devs_max;
3555         devs_min = btrfs_raid_array[index].devs_min;
3556         devs_increment = btrfs_raid_array[index].devs_increment;
3557         ncopies = btrfs_raid_array[index].ncopies;
3558
3559         if (type & BTRFS_BLOCK_GROUP_DATA) {
3560                 max_stripe_size = 1024 * 1024 * 1024;
3561                 max_chunk_size = 10 * max_stripe_size;
3562         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
3563                 /* for larger filesystems, use larger metadata chunks */
3564                 if (fs_devices->total_rw_bytes > 50ULL * 1024 * 1024 * 1024)
3565                         max_stripe_size = 1024 * 1024 * 1024;
3566                 else
3567                         max_stripe_size = 256 * 1024 * 1024;
3568                 max_chunk_size = max_stripe_size;
3569         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
3570                 max_stripe_size = 32 * 1024 * 1024;
3571                 max_chunk_size = 2 * max_stripe_size;
3572         } else {
3573                 printk(KERN_ERR "btrfs: invalid chunk type 0x%llx requested\n",
3574                        type);
3575                 BUG_ON(1);
3576         }
3577
3578         /* we don't want a chunk larger than 10% of writeable space */
3579         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
3580                              max_chunk_size);
3581
3582         devices_info = kzalloc(sizeof(*devices_info) * fs_devices->rw_devices,
3583                                GFP_NOFS);
3584         if (!devices_info)
3585                 return -ENOMEM;
3586
3587         cur = fs_devices->alloc_list.next;
3588
3589         /*
3590          * in the first pass through the devices list, we gather information
3591          * about the available holes on each device.
3592          */
3593         ndevs = 0;
3594         while (cur != &fs_devices->alloc_list) {
3595                 struct btrfs_device *device;
3596                 u64 max_avail;
3597                 u64 dev_offset;
3598
3599                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
3600
3601                 cur = cur->next;
3602
3603                 if (!device->writeable) {
3604                         WARN(1, KERN_ERR
3605                                "btrfs: read-only device in alloc_list\n");
3606                         continue;
3607                 }
3608
3609                 if (!device->in_fs_metadata ||
3610                     device->is_tgtdev_for_dev_replace)
3611                         continue;
3612
3613                 if (device->total_bytes > device->bytes_used)
3614                         total_avail = device->total_bytes - device->bytes_used;
3615                 else
3616                         total_avail = 0;
3617
3618                 /* If there is no space on this device, skip it. */
3619                 if (total_avail == 0)
3620                         continue;
3621
3622                 ret = find_free_dev_extent(device,
3623                                            max_stripe_size * dev_stripes,
3624                                            &dev_offset, &max_avail);
3625                 if (ret && ret != -ENOSPC)
3626                         goto error;
3627
3628                 if (ret == 0)
3629                         max_avail = max_stripe_size * dev_stripes;
3630
3631                 if (max_avail < BTRFS_STRIPE_LEN * dev_stripes)
3632                         continue;
3633
3634                 devices_info[ndevs].dev_offset = dev_offset;
3635                 devices_info[ndevs].max_avail = max_avail;
3636                 devices_info[ndevs].total_avail = total_avail;
3637                 devices_info[ndevs].dev = device;
3638                 ++ndevs;
3639                 WARN_ON(ndevs > fs_devices->rw_devices);
3640         }
3641
3642         /*
3643          * now sort the devices by hole size / available space
3644          */
3645         sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
3646              btrfs_cmp_device_info, NULL);
3647
3648         /* round down to number of usable stripes */
3649         ndevs -= ndevs % devs_increment;
3650
3651         if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
3652                 ret = -ENOSPC;
3653                 goto error;
3654         }
3655
3656         if (devs_max && ndevs > devs_max)
3657                 ndevs = devs_max;
3658         /*
3659          * the primary goal is to maximize the number of stripes, so use as many
3660          * devices as possible, even if the stripes are not maximum sized.
3661          */
3662         stripe_size = devices_info[ndevs-1].max_avail;
3663         num_stripes = ndevs * dev_stripes;
3664
3665         if (stripe_size * ndevs > max_chunk_size * ncopies) {
3666                 stripe_size = max_chunk_size * ncopies;
3667                 do_div(stripe_size, ndevs);
3668         }
3669
3670         do_div(stripe_size, dev_stripes);
3671
3672         /* align to BTRFS_STRIPE_LEN */
3673         do_div(stripe_size, BTRFS_STRIPE_LEN);
3674         stripe_size *= BTRFS_STRIPE_LEN;
3675
3676         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
3677         if (!map) {
3678                 ret = -ENOMEM;
3679                 goto error;
3680         }
3681         map->num_stripes = num_stripes;
3682
3683         for (i = 0; i < ndevs; ++i) {
3684                 for (j = 0; j < dev_stripes; ++j) {
3685                         int s = i * dev_stripes + j;
3686                         map->stripes[s].dev = devices_info[i].dev;
3687                         map->stripes[s].physical = devices_info[i].dev_offset +
3688                                                    j * stripe_size;
3689                 }
3690         }
3691         map->sector_size = extent_root->sectorsize;
3692         map->stripe_len = BTRFS_STRIPE_LEN;
3693         map->io_align = BTRFS_STRIPE_LEN;
3694         map->io_width = BTRFS_STRIPE_LEN;
3695         map->type = type;
3696         map->sub_stripes = sub_stripes;
3697
3698         *map_ret = map;
3699         num_bytes = stripe_size * (num_stripes / ncopies);
3700
3701         *stripe_size_out = stripe_size;
3702         *num_bytes_out = num_bytes;
3703
3704         trace_btrfs_chunk_alloc(info->chunk_root, map, start, num_bytes);
3705
3706         em = alloc_extent_map();
3707         if (!em) {
3708                 ret = -ENOMEM;
3709                 goto error;
3710         }
3711         em->bdev = (struct block_device *)map;
3712         em->start = start;
3713         em->len = num_bytes;
3714         em->block_start = 0;
3715         em->block_len = em->len;
3716
3717         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
3718         write_lock(&em_tree->lock);
3719         ret = add_extent_mapping(em_tree, em);
3720         write_unlock(&em_tree->lock);
3721         free_extent_map(em);
3722         if (ret)
3723                 goto error;
3724
3725         ret = btrfs_make_block_group(trans, extent_root, 0, type,
3726                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3727                                      start, num_bytes);
3728         if (ret)
3729                 goto error;
3730
3731         for (i = 0; i < map->num_stripes; ++i) {
3732                 struct btrfs_device *device;
3733                 u64 dev_offset;
3734
3735                 device = map->stripes[i].dev;
3736                 dev_offset = map->stripes[i].physical;
3737
3738                 ret = btrfs_alloc_dev_extent(trans, device,
3739                                 info->chunk_root->root_key.objectid,
3740                                 BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3741                                 start, dev_offset, stripe_size);
3742                 if (ret) {
3743                         btrfs_abort_transaction(trans, extent_root, ret);
3744                         goto error;
3745                 }
3746         }
3747
3748         kfree(devices_info);
3749         return 0;
3750
3751 error:
3752         kfree(map);
3753         kfree(devices_info);
3754         return ret;
3755 }
3756
3757 static int __finish_chunk_alloc(struct btrfs_trans_handle *trans,
3758                                 struct btrfs_root *extent_root,
3759                                 struct map_lookup *map, u64 chunk_offset,
3760                                 u64 chunk_size, u64 stripe_size)
3761 {
3762         u64 dev_offset;
3763         struct btrfs_key key;
3764         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
3765         struct btrfs_device *device;
3766         struct btrfs_chunk *chunk;
3767         struct btrfs_stripe *stripe;
3768         size_t item_size = btrfs_chunk_item_size(map->num_stripes);
3769         int index = 0;
3770         int ret;
3771
3772         chunk = kzalloc(item_size, GFP_NOFS);
3773         if (!chunk)
3774                 return -ENOMEM;
3775
3776         index = 0;
3777         while (index < map->num_stripes) {
3778                 device = map->stripes[index].dev;
3779                 device->bytes_used += stripe_size;
3780                 ret = btrfs_update_device(trans, device);
3781                 if (ret)
3782                         goto out_free;
3783                 index++;
3784         }
3785
3786         spin_lock(&extent_root->fs_info->free_chunk_lock);
3787         extent_root->fs_info->free_chunk_space -= (stripe_size *
3788                                                    map->num_stripes);
3789         spin_unlock(&extent_root->fs_info->free_chunk_lock);
3790
3791         index = 0;
3792         stripe = &chunk->stripe;
3793         while (index < map->num_stripes) {
3794                 device = map->stripes[index].dev;
3795                 dev_offset = map->stripes[index].physical;
3796
3797                 btrfs_set_stack_stripe_devid(stripe, device->devid);
3798                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
3799                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
3800                 stripe++;
3801                 index++;
3802         }
3803
3804         btrfs_set_stack_chunk_length(chunk, chunk_size);
3805         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
3806         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
3807         btrfs_set_stack_chunk_type(chunk, map->type);
3808         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
3809         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
3810         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
3811         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
3812         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
3813
3814         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
3815         key.type = BTRFS_CHUNK_ITEM_KEY;
3816         key.offset = chunk_offset;
3817
3818         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
3819
3820         if (ret == 0 && map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
3821                 /*
3822                  * TODO: Cleanup of inserted chunk root in case of
3823                  * failure.
3824                  */
3825                 ret = btrfs_add_system_chunk(chunk_root, &key, chunk,
3826                                              item_size);
3827         }
3828
3829 out_free:
3830         kfree(chunk);
3831         return ret;
3832 }
3833
3834 /*
3835  * Chunk allocation falls into two parts. The first part does works
3836  * that make the new allocated chunk useable, but not do any operation
3837  * that modifies the chunk tree. The second part does the works that
3838  * require modifying the chunk tree. This division is important for the
3839  * bootstrap process of adding storage to a seed btrfs.
3840  */
3841 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
3842                       struct btrfs_root *extent_root, u64 type)
3843 {
3844         u64 chunk_offset;
3845         u64 chunk_size;
3846         u64 stripe_size;
3847         struct map_lookup *map;
3848         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
3849         int ret;
3850
3851         ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3852                               &chunk_offset);
3853         if (ret)
3854                 return ret;
3855
3856         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
3857                                   &stripe_size, chunk_offset, type);
3858         if (ret)
3859                 return ret;
3860
3861         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
3862                                    chunk_size, stripe_size);
3863         if (ret)
3864                 return ret;
3865         return 0;
3866 }
3867
3868 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
3869                                          struct btrfs_root *root,
3870                                          struct btrfs_device *device)
3871 {
3872         u64 chunk_offset;
3873         u64 sys_chunk_offset;
3874         u64 chunk_size;
3875         u64 sys_chunk_size;
3876         u64 stripe_size;
3877         u64 sys_stripe_size;
3878         u64 alloc_profile;
3879         struct map_lookup *map;
3880         struct map_lookup *sys_map;
3881         struct btrfs_fs_info *fs_info = root->fs_info;
3882         struct btrfs_root *extent_root = fs_info->extent_root;
3883         int ret;
3884
3885         ret = find_next_chunk(fs_info->chunk_root,
3886                               BTRFS_FIRST_CHUNK_TREE_OBJECTID, &chunk_offset);
3887         if (ret)
3888                 return ret;
3889
3890         alloc_profile = BTRFS_BLOCK_GROUP_METADATA |
3891                                 fs_info->avail_metadata_alloc_bits;
3892         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
3893
3894         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
3895                                   &stripe_size, chunk_offset, alloc_profile);
3896         if (ret)
3897                 return ret;
3898
3899         sys_chunk_offset = chunk_offset + chunk_size;
3900
3901         alloc_profile = BTRFS_BLOCK_GROUP_SYSTEM |
3902                                 fs_info->avail_system_alloc_bits;
3903         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
3904
3905         ret = __btrfs_alloc_chunk(trans, extent_root, &sys_map,
3906                                   &sys_chunk_size, &sys_stripe_size,
3907                                   sys_chunk_offset, alloc_profile);
3908         if (ret) {
3909                 btrfs_abort_transaction(trans, root, ret);
3910                 goto out;
3911         }
3912
3913         ret = btrfs_add_device(trans, fs_info->chunk_root, device);
3914         if (ret) {
3915                 btrfs_abort_transaction(trans, root, ret);
3916                 goto out;
3917         }
3918
3919         /*
3920          * Modifying chunk tree needs allocating new blocks from both
3921          * system block group and metadata block group. So we only can
3922          * do operations require modifying the chunk tree after both
3923          * block groups were created.
3924          */
3925         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
3926                                    chunk_size, stripe_size);
3927         if (ret) {
3928                 btrfs_abort_transaction(trans, root, ret);
3929                 goto out;
3930         }
3931
3932         ret = __finish_chunk_alloc(trans, extent_root, sys_map,
3933                                    sys_chunk_offset, sys_chunk_size,
3934                                    sys_stripe_size);
3935         if (ret)
3936                 btrfs_abort_transaction(trans, root, ret);
3937
3938 out:
3939
3940         return ret;
3941 }
3942
3943 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
3944 {
3945         struct extent_map *em;
3946         struct map_lookup *map;
3947         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
3948         int readonly = 0;
3949         int i;
3950
3951         read_lock(&map_tree->map_tree.lock);
3952         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
3953         read_unlock(&map_tree->map_tree.lock);
3954         if (!em)
3955                 return 1;
3956
3957         if (btrfs_test_opt(root, DEGRADED)) {
3958                 free_extent_map(em);
3959                 return 0;
3960         }
3961
3962         map = (struct map_lookup *)em->bdev;
3963         for (i = 0; i < map->num_stripes; i++) {
3964                 if (!map->stripes[i].dev->writeable) {
3965                         readonly = 1;
3966                         break;
3967                 }
3968         }
3969         free_extent_map(em);
3970         return readonly;
3971 }
3972
3973 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
3974 {
3975         extent_map_tree_init(&tree->map_tree);
3976 }
3977
3978 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
3979 {
3980         struct extent_map *em;
3981
3982         while (1) {
3983                 write_lock(&tree->map_tree.lock);
3984                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
3985                 if (em)
3986                         remove_extent_mapping(&tree->map_tree, em);
3987                 write_unlock(&tree->map_tree.lock);
3988                 if (!em)
3989                         break;
3990                 kfree(em->bdev);
3991                 /* once for us */
3992                 free_extent_map(em);
3993                 /* once for the tree */
3994                 free_extent_map(em);
3995         }
3996 }
3997
3998 int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
3999 {
4000         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
4001         struct extent_map *em;
4002         struct map_lookup *map;
4003         struct extent_map_tree *em_tree = &map_tree->map_tree;
4004         int ret;
4005
4006         read_lock(&em_tree->lock);
4007         em = lookup_extent_mapping(em_tree, logical, len);
4008         read_unlock(&em_tree->lock);
4009         BUG_ON(!em);
4010
4011         BUG_ON(em->start > logical || em->start + em->len < logical);
4012         map = (struct map_lookup *)em->bdev;
4013         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
4014                 ret = map->num_stripes;
4015         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
4016                 ret = map->sub_stripes;
4017         else
4018                 ret = 1;
4019         free_extent_map(em);
4020
4021         btrfs_dev_replace_lock(&fs_info->dev_replace);
4022         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))
4023                 ret++;
4024         btrfs_dev_replace_unlock(&fs_info->dev_replace);
4025
4026         return ret;
4027 }
4028
4029 static int find_live_mirror(struct btrfs_fs_info *fs_info,
4030                             struct map_lookup *map, int first, int num,
4031                             int optimal, int dev_replace_is_ongoing)
4032 {
4033         int i;
4034         int tolerance;
4035         struct btrfs_device *srcdev;
4036
4037         if (dev_replace_is_ongoing &&
4038             fs_info->dev_replace.cont_reading_from_srcdev_mode ==
4039              BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID)
4040                 srcdev = fs_info->dev_replace.srcdev;
4041         else
4042                 srcdev = NULL;
4043
4044         /*
4045          * try to avoid the drive that is the source drive for a
4046          * dev-replace procedure, only choose it if no other non-missing
4047          * mirror is available
4048          */
4049         for (tolerance = 0; tolerance < 2; tolerance++) {
4050                 if (map->stripes[optimal].dev->bdev &&
4051                     (tolerance || map->stripes[optimal].dev != srcdev))
4052                         return optimal;
4053                 for (i = first; i < first + num; i++) {
4054                         if (map->stripes[i].dev->bdev &&
4055                             (tolerance || map->stripes[i].dev != srcdev))
4056                                 return i;
4057                 }
4058         }
4059
4060         /* we couldn't find one that doesn't fail.  Just return something
4061          * and the io error handling code will clean up eventually
4062          */
4063         return optimal;
4064 }
4065
4066 static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
4067                              u64 logical, u64 *length,
4068                              struct btrfs_bio **bbio_ret,
4069                              int mirror_num)
4070 {
4071         struct extent_map *em;
4072         struct map_lookup *map;
4073         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
4074         struct extent_map_tree *em_tree = &map_tree->map_tree;
4075         u64 offset;
4076         u64 stripe_offset;
4077         u64 stripe_end_offset;
4078         u64 stripe_nr;
4079         u64 stripe_nr_orig;
4080         u64 stripe_nr_end;
4081         int stripe_index;
4082         int i;
4083         int ret = 0;
4084         int num_stripes;
4085         int max_errors = 0;
4086         struct btrfs_bio *bbio = NULL;
4087         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
4088         int dev_replace_is_ongoing = 0;
4089         int num_alloc_stripes;
4090         int patch_the_first_stripe_for_dev_replace = 0;
4091         u64 physical_to_patch_in_first_stripe = 0;
4092
4093         read_lock(&em_tree->lock);
4094         em = lookup_extent_mapping(em_tree, logical, *length);
4095         read_unlock(&em_tree->lock);
4096
4097         if (!em) {
4098                 printk(KERN_CRIT "btrfs: unable to find logical %llu len %llu\n",
4099                        (unsigned long long)logical,
4100                        (unsigned long long)*length);
4101                 BUG();
4102         }
4103
4104         BUG_ON(em->start > logical || em->start + em->len < logical);
4105         map = (struct map_lookup *)em->bdev;
4106         offset = logical - em->start;
4107
4108         stripe_nr = offset;
4109         /*
4110          * stripe_nr counts the total number of stripes we have to stride
4111          * to get to this block
4112          */
4113         do_div(stripe_nr, map->stripe_len);
4114
4115         stripe_offset = stripe_nr * map->stripe_len;
4116         BUG_ON(offset < stripe_offset);
4117
4118         /* stripe_offset is the offset of this block in its stripe*/
4119         stripe_offset = offset - stripe_offset;
4120
4121         if (rw & REQ_DISCARD)
4122                 *length = min_t(u64, em->len - offset, *length);
4123         else if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
4124                 /* we limit the length of each bio to what fits in a stripe */
4125                 *length = min_t(u64, em->len - offset,
4126                                 map->stripe_len - stripe_offset);
4127         } else {
4128                 *length = em->len - offset;
4129         }
4130
4131         if (!bbio_ret)
4132                 goto out;
4133
4134         btrfs_dev_replace_lock(dev_replace);
4135         dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(dev_replace);
4136         if (!dev_replace_is_ongoing)
4137                 btrfs_dev_replace_unlock(dev_replace);
4138
4139         if (dev_replace_is_ongoing && mirror_num == map->num_stripes + 1 &&
4140             !(rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) &&
4141             dev_replace->tgtdev != NULL) {
4142                 /*
4143                  * in dev-replace case, for repair case (that's the only
4144                  * case where the mirror is selected explicitly when
4145                  * calling btrfs_map_block), blocks left of the left cursor
4146                  * can also be read from the target drive.
4147                  * For REQ_GET_READ_MIRRORS, the target drive is added as
4148                  * the last one to the array of stripes. For READ, it also
4149                  * needs to be supported using the same mirror number.
4150                  * If the requested block is not left of the left cursor,
4151                  * EIO is returned. This can happen because btrfs_num_copies()
4152                  * returns one more in the dev-replace case.
4153                  */
4154                 u64 tmp_length = *length;
4155                 struct btrfs_bio *tmp_bbio = NULL;
4156                 int tmp_num_stripes;
4157                 u64 srcdev_devid = dev_replace->srcdev->devid;
4158                 int index_srcdev = 0;
4159                 int found = 0;
4160                 u64 physical_of_found = 0;
4161
4162                 ret = __btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS,
4163                              logical, &tmp_length, &tmp_bbio, 0);
4164                 if (ret) {
4165                         WARN_ON(tmp_bbio != NULL);
4166                         goto out;
4167                 }
4168
4169                 tmp_num_stripes = tmp_bbio->num_stripes;
4170                 if (mirror_num > tmp_num_stripes) {
4171                         /*
4172                          * REQ_GET_READ_MIRRORS does not contain this
4173                          * mirror, that means that the requested area
4174                          * is not left of the left cursor
4175                          */
4176                         ret = -EIO;
4177                         kfree(tmp_bbio);
4178                         goto out;
4179                 }
4180
4181                 /*
4182                  * process the rest of the function using the mirror_num
4183                  * of the source drive. Therefore look it up first.
4184                  * At the end, patch the device pointer to the one of the
4185                  * target drive.
4186                  */
4187                 for (i = 0; i < tmp_num_stripes; i++) {
4188                         if (tmp_bbio->stripes[i].dev->devid == srcdev_devid) {
4189                                 /*
4190                                  * In case of DUP, in order to keep it
4191                                  * simple, only add the mirror with the
4192                                  * lowest physical address
4193                                  */
4194                                 if (found &&
4195                                     physical_of_found <=
4196                                      tmp_bbio->stripes[i].physical)
4197                                         continue;
4198                                 index_srcdev = i;
4199                                 found = 1;
4200                                 physical_of_found =
4201                                         tmp_bbio->stripes[i].physical;
4202                         }
4203                 }
4204
4205                 if (found) {
4206                         mirror_num = index_srcdev + 1;
4207                         patch_the_first_stripe_for_dev_replace = 1;
4208                         physical_to_patch_in_first_stripe = physical_of_found;
4209                 } else {
4210                         WARN_ON(1);
4211                         ret = -EIO;
4212                         kfree(tmp_bbio);
4213                         goto out;
4214                 }
4215
4216                 kfree(tmp_bbio);
4217         } else if (mirror_num > map->num_stripes) {
4218                 mirror_num = 0;
4219         }
4220
4221         num_stripes = 1;
4222         stripe_index = 0;
4223         stripe_nr_orig = stripe_nr;
4224         stripe_nr_end = (offset + *length + map->stripe_len - 1) &
4225                         (~(map->stripe_len - 1));
4226         do_div(stripe_nr_end, map->stripe_len);
4227         stripe_end_offset = stripe_nr_end * map->stripe_len -
4228                             (offset + *length);
4229         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
4230                 if (rw & REQ_DISCARD)
4231                         num_stripes = min_t(u64, map->num_stripes,
4232                                             stripe_nr_end - stripe_nr_orig);
4233                 stripe_index = do_div(stripe_nr, map->num_stripes);
4234         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
4235                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS))
4236                         num_stripes = map->num_stripes;
4237                 else if (mirror_num)
4238                         stripe_index = mirror_num - 1;
4239                 else {
4240                         stripe_index = find_live_mirror(fs_info, map, 0,
4241                                             map->num_stripes,
4242                                             current->pid % map->num_stripes,
4243                                             dev_replace_is_ongoing);
4244                         mirror_num = stripe_index + 1;
4245                 }
4246
4247         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
4248                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) {
4249                         num_stripes = map->num_stripes;
4250                 } else if (mirror_num) {
4251                         stripe_index = mirror_num - 1;
4252                 } else {
4253                         mirror_num = 1;
4254                 }
4255
4256         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
4257                 int factor = map->num_stripes / map->sub_stripes;
4258
4259                 stripe_index = do_div(stripe_nr, factor);
4260                 stripe_index *= map->sub_stripes;
4261
4262                 if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS))
4263                         num_stripes = map->sub_stripes;
4264                 else if (rw & REQ_DISCARD)
4265                         num_stripes = min_t(u64, map->sub_stripes *
4266                                             (stripe_nr_end - stripe_nr_orig),
4267                                             map->num_stripes);
4268                 else if (mirror_num)
4269                         stripe_index += mirror_num - 1;
4270                 else {
4271                         int old_stripe_index = stripe_index;
4272                         stripe_index = find_live_mirror(fs_info, map,
4273                                               stripe_index,
4274                                               map->sub_stripes, stripe_index +
4275                                               current->pid % map->sub_stripes,
4276                                               dev_replace_is_ongoing);
4277                         mirror_num = stripe_index - old_stripe_index + 1;
4278                 }
4279         } else {
4280                 /*
4281                  * after this do_div call, stripe_nr is the number of stripes
4282                  * on this device we have to walk to find the data, and
4283                  * stripe_index is the number of our device in the stripe array
4284                  */
4285                 stripe_index = do_div(stripe_nr, map->num_stripes);
4286                 mirror_num = stripe_index + 1;
4287         }
4288         BUG_ON(stripe_index >= map->num_stripes);
4289
4290         num_alloc_stripes = num_stripes;
4291         if (dev_replace_is_ongoing) {
4292                 if (rw & (REQ_WRITE | REQ_DISCARD))
4293                         num_alloc_stripes <<= 1;
4294                 if (rw & REQ_GET_READ_MIRRORS)
4295                         num_alloc_stripes++;
4296         }
4297         bbio = kzalloc(btrfs_bio_size(num_alloc_stripes), GFP_NOFS);
4298         if (!bbio) {
4299                 ret = -ENOMEM;
4300                 goto out;
4301         }
4302         atomic_set(&bbio->error, 0);
4303
4304         if (rw & REQ_DISCARD) {
4305                 int factor = 0;
4306                 int sub_stripes = 0;
4307                 u64 stripes_per_dev = 0;
4308                 u32 remaining_stripes = 0;
4309                 u32 last_stripe = 0;
4310
4311                 if (map->type &
4312                     (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
4313                         if (map->type & BTRFS_BLOCK_GROUP_RAID0)
4314                                 sub_stripes = 1;
4315                         else
4316                                 sub_stripes = map->sub_stripes;
4317
4318                         factor = map->num_stripes / sub_stripes;
4319                         stripes_per_dev = div_u64_rem(stripe_nr_end -
4320                                                       stripe_nr_orig,
4321                                                       factor,
4322                                                       &remaining_stripes);
4323                         div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
4324                         last_stripe *= sub_stripes;
4325                 }
4326
4327                 for (i = 0; i < num_stripes; i++) {
4328                         bbio->stripes[i].physical =
4329                                 map->stripes[stripe_index].physical +
4330                                 stripe_offset + stripe_nr * map->stripe_len;
4331                         bbio->stripes[i].dev = map->stripes[stripe_index].dev;
4332
4333                         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
4334                                          BTRFS_BLOCK_GROUP_RAID10)) {
4335                                 bbio->stripes[i].length = stripes_per_dev *
4336                                                           map->stripe_len;
4337
4338                                 if (i / sub_stripes < remaining_stripes)
4339                                         bbio->stripes[i].length +=
4340                                                 map->stripe_len;
4341
4342                                 /*
4343                                  * Special for the first stripe and
4344                                  * the last stripe:
4345                                  *
4346                                  * |-------|...|-------|
4347                                  *     |----------|
4348                                  *    off     end_off
4349                                  */
4350                                 if (i < sub_stripes)
4351                                         bbio->stripes[i].length -=
4352                                                 stripe_offset;
4353
4354                                 if (stripe_index >= last_stripe &&
4355                                     stripe_index <= (last_stripe +
4356                                                      sub_stripes - 1))
4357                                         bbio->stripes[i].length -=
4358                                                 stripe_end_offset;
4359
4360                                 if (i == sub_stripes - 1)
4361                                         stripe_offset = 0;
4362                         } else
4363                                 bbio->stripes[i].length = *length;
4364
4365                         stripe_index++;
4366                         if (stripe_index == map->num_stripes) {
4367                                 /* This could only happen for RAID0/10 */
4368                                 stripe_index = 0;
4369                                 stripe_nr++;
4370                         }
4371                 }
4372         } else {
4373                 for (i = 0; i < num_stripes; i++) {
4374                         bbio->stripes[i].physical =
4375                                 map->stripes[stripe_index].physical +
4376                                 stripe_offset +
4377                                 stripe_nr * map->stripe_len;
4378                         bbio->stripes[i].dev =
4379                                 map->stripes[stripe_index].dev;
4380                         stripe_index++;
4381                 }
4382         }
4383
4384         if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS)) {
4385                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
4386                                  BTRFS_BLOCK_GROUP_RAID10 |
4387                                  BTRFS_BLOCK_GROUP_DUP)) {
4388                         max_errors = 1;
4389                 }
4390         }
4391
4392         if (dev_replace_is_ongoing && (rw & (REQ_WRITE | REQ_DISCARD)) &&
4393             dev_replace->tgtdev != NULL) {
4394                 int index_where_to_add;
4395                 u64 srcdev_devid = dev_replace->srcdev->devid;
4396
4397                 /*
4398                  * duplicate the write operations while the dev replace
4399                  * procedure is running. Since the copying of the old disk
4400                  * to the new disk takes place at run time while the
4401                  * filesystem is mounted writable, the regular write
4402                  * operations to the old disk have to be duplicated to go
4403                  * to the new disk as well.
4404                  * Note that device->missing is handled by the caller, and
4405                  * that the write to the old disk is already set up in the
4406                  * stripes array.
4407                  */
4408                 index_where_to_add = num_stripes;
4409                 for (i = 0; i < num_stripes; i++) {
4410                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
4411                                 /* write to new disk, too */
4412                                 struct btrfs_bio_stripe *new =
4413                                         bbio->stripes + index_where_to_add;
4414                                 struct btrfs_bio_stripe *old =
4415                                         bbio->stripes + i;
4416
4417                                 new->physical = old->physical;
4418                                 new->length = old->length;
4419                                 new->dev = dev_replace->tgtdev;
4420                                 index_where_to_add++;
4421                                 max_errors++;
4422                         }
4423                 }
4424                 num_stripes = index_where_to_add;
4425         } else if (dev_replace_is_ongoing && (rw & REQ_GET_READ_MIRRORS) &&
4426                    dev_replace->tgtdev != NULL) {
4427                 u64 srcdev_devid = dev_replace->srcdev->devid;
4428                 int index_srcdev = 0;
4429                 int found = 0;
4430                 u64 physical_of_found = 0;
4431
4432                 /*
4433                  * During the dev-replace procedure, the target drive can
4434                  * also be used to read data in case it is needed to repair
4435                  * a corrupt block elsewhere. This is possible if the
4436                  * requested area is left of the left cursor. In this area,
4437                  * the target drive is a full copy of the source drive.
4438                  */
4439                 for (i = 0; i < num_stripes; i++) {
4440                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
4441                                 /*
4442                                  * In case of DUP, in order to keep it
4443                                  * simple, only add the mirror with the
4444                                  * lowest physical address
4445                                  */
4446                                 if (found &&
4447                                     physical_of_found <=
4448                                      bbio->stripes[i].physical)
4449                                         continue;
4450                                 index_srcdev = i;
4451                                 found = 1;
4452                                 physical_of_found = bbio->stripes[i].physical;
4453                         }
4454                 }
4455                 if (found) {
4456                         u64 length = map->stripe_len;
4457
4458                         if (physical_of_found + length <=
4459                             dev_replace->cursor_left) {
4460                                 struct btrfs_bio_stripe *tgtdev_stripe =
4461                                         bbio->stripes + num_stripes;
4462
4463                                 tgtdev_stripe->physical = physical_of_found;
4464                                 tgtdev_stripe->length =
4465                                         bbio->stripes[index_srcdev].length;
4466                                 tgtdev_stripe->dev = dev_replace->tgtdev;
4467
4468                                 num_stripes++;
4469                         }
4470                 }
4471         }
4472
4473         *bbio_ret = bbio;
4474         bbio->num_stripes = num_stripes;
4475         bbio->max_errors = max_errors;
4476         bbio->mirror_num = mirror_num;
4477
4478         /*
4479          * this is the case that REQ_READ && dev_replace_is_ongoing &&
4480          * mirror_num == num_stripes + 1 && dev_replace target drive is
4481          * available as a mirror
4482          */
4483         if (patch_the_first_stripe_for_dev_replace && num_stripes > 0) {
4484                 WARN_ON(num_stripes > 1);
4485                 bbio->stripes[0].dev = dev_replace->tgtdev;
4486                 bbio->stripes[0].physical = physical_to_patch_in_first_stripe;
4487                 bbio->mirror_num = map->num_stripes + 1;
4488         }
4489 out:
4490         if (dev_replace_is_ongoing)
4491                 btrfs_dev_replace_unlock(dev_replace);
4492         free_extent_map(em);
4493         return ret;
4494 }
4495
4496 int btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
4497                       u64 logical, u64 *length,
4498                       struct btrfs_bio **bbio_ret, int mirror_num)
4499 {
4500         return __btrfs_map_block(fs_info, rw, logical, length, bbio_ret,
4501                                  mirror_num);
4502 }
4503
4504 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
4505                      u64 chunk_start, u64 physical, u64 devid,
4506                      u64 **logical, int *naddrs, int *stripe_len)
4507 {
4508         struct extent_map_tree *em_tree = &map_tree->map_tree;
4509         struct extent_map *em;
4510         struct map_lookup *map;
4511         u64 *buf;
4512         u64 bytenr;
4513         u64 length;
4514         u64 stripe_nr;
4515         int i, j, nr = 0;
4516
4517         read_lock(&em_tree->lock);
4518         em = lookup_extent_mapping(em_tree, chunk_start, 1);
4519         read_unlock(&em_tree->lock);
4520
4521         BUG_ON(!em || em->start != chunk_start);
4522         map = (struct map_lookup *)em->bdev;
4523
4524         length = em->len;
4525         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
4526                 do_div(length, map->num_stripes / map->sub_stripes);
4527         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
4528                 do_div(length, map->num_stripes);
4529
4530         buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
4531         BUG_ON(!buf); /* -ENOMEM */
4532
4533         for (i = 0; i < map->num_stripes; i++) {
4534                 if (devid && map->stripes[i].dev->devid != devid)
4535                         continue;
4536                 if (map->stripes[i].physical > physical ||
4537                     map->stripes[i].physical + length <= physical)
4538                         continue;
4539
4540                 stripe_nr = physical - map->stripes[i].physical;
4541                 do_div(stripe_nr, map->stripe_len);
4542
4543                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
4544                         stripe_nr = stripe_nr * map->num_stripes + i;
4545                         do_div(stripe_nr, map->sub_stripes);
4546                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
4547                         stripe_nr = stripe_nr * map->num_stripes + i;
4548                 }
4549                 bytenr = chunk_start + stripe_nr * map->stripe_len;
4550                 WARN_ON(nr >= map->num_stripes);
4551                 for (j = 0; j < nr; j++) {
4552                         if (buf[j] == bytenr)
4553                                 break;
4554                 }
4555                 if (j == nr) {
4556                         WARN_ON(nr >= map->num_stripes);
4557                         buf[nr++] = bytenr;
4558                 }
4559         }
4560
4561         *logical = buf;
4562         *naddrs = nr;
4563         *stripe_len = map->stripe_len;
4564
4565         free_extent_map(em);
4566         return 0;
4567 }
4568
4569 static void *merge_stripe_index_into_bio_private(void *bi_private,
4570                                                  unsigned int stripe_index)
4571 {
4572         /*
4573          * with single, dup, RAID0, RAID1 and RAID10, stripe_index is
4574          * at most 1.
4575          * The alternative solution (instead of stealing bits from the
4576          * pointer) would be to allocate an intermediate structure
4577          * that contains the old private pointer plus the stripe_index.
4578          */
4579         BUG_ON((((uintptr_t)bi_private) & 3) != 0);
4580         BUG_ON(stripe_index > 3);
4581         return (void *)(((uintptr_t)bi_private) | stripe_index);
4582 }
4583
4584 static struct btrfs_bio *extract_bbio_from_bio_private(void *bi_private)
4585 {
4586         return (struct btrfs_bio *)(((uintptr_t)bi_private) & ~((uintptr_t)3));
4587 }
4588
4589 static unsigned int extract_stripe_index_from_bio_private(void *bi_private)
4590 {
4591         return (unsigned int)((uintptr_t)bi_private) & 3;
4592 }
4593
4594 static void btrfs_end_bio(struct bio *bio, int err)
4595 {
4596         struct btrfs_bio *bbio = extract_bbio_from_bio_private(bio->bi_private);
4597         int is_orig_bio = 0;
4598
4599         if (err) {
4600                 atomic_inc(&bbio->error);
4601                 if (err == -EIO || err == -EREMOTEIO) {
4602                         unsigned int stripe_index =
4603                                 extract_stripe_index_from_bio_private(
4604                                         bio->bi_private);
4605                         struct btrfs_device *dev;
4606
4607                         BUG_ON(stripe_index >= bbio->num_stripes);
4608                         dev = bbio->stripes[stripe_index].dev;
4609                         if (dev->bdev) {
4610                                 if (bio->bi_rw & WRITE)
4611                                         btrfs_dev_stat_inc(dev,
4612                                                 BTRFS_DEV_STAT_WRITE_ERRS);
4613                                 else
4614                                         btrfs_dev_stat_inc(dev,
4615                                                 BTRFS_DEV_STAT_READ_ERRS);
4616                                 if ((bio->bi_rw & WRITE_FLUSH) == WRITE_FLUSH)
4617                                         btrfs_dev_stat_inc(dev,
4618                                                 BTRFS_DEV_STAT_FLUSH_ERRS);
4619                                 btrfs_dev_stat_print_on_error(dev);
4620                         }
4621                 }
4622         }
4623
4624         if (bio == bbio->orig_bio)
4625                 is_orig_bio = 1;
4626
4627         if (atomic_dec_and_test(&bbio->stripes_pending)) {
4628                 if (!is_orig_bio) {
4629                         bio_put(bio);
4630                         bio = bbio->orig_bio;
4631                 }
4632                 bio->bi_private = bbio->private;
4633                 bio->bi_end_io = bbio->end_io;
4634                 bio->bi_bdev = (struct block_device *)
4635                                         (unsigned long)bbio->mirror_num;
4636                 /* only send an error to the higher layers if it is
4637                  * beyond the tolerance of the multi-bio
4638                  */
4639                 if (atomic_read(&bbio->error) > bbio->max_errors) {
4640                         err = -EIO;
4641                 } else {
4642                         /*
4643                          * this bio is actually up to date, we didn't
4644                          * go over the max number of errors
4645                          */
4646                         set_bit(BIO_UPTODATE, &bio->bi_flags);
4647                         err = 0;
4648                 }
4649                 kfree(bbio);
4650
4651                 bio_endio(bio, err);
4652         } else if (!is_orig_bio) {
4653                 bio_put(bio);
4654         }
4655 }
4656
4657 struct async_sched {
4658         struct bio *bio;
4659         int rw;
4660         struct btrfs_fs_info *info;
4661         struct btrfs_work work;
4662 };
4663
4664 /*
4665  * see run_scheduled_bios for a description of why bios are collected for
4666  * async submit.
4667  *
4668  * This will add one bio to the pending list for a device and make sure
4669  * the work struct is scheduled.
4670  */
4671 static noinline void schedule_bio(struct btrfs_root *root,
4672                                  struct btrfs_device *device,
4673                                  int rw, struct bio *bio)
4674 {
4675         int should_queue = 1;
4676         struct btrfs_pending_bios *pending_bios;
4677
4678         /* don't bother with additional async steps for reads, right now */
4679         if (!(rw & REQ_WRITE)) {
4680                 bio_get(bio);
4681                 btrfsic_submit_bio(rw, bio);
4682                 bio_put(bio);
4683                 return;
4684         }
4685
4686         /*
4687          * nr_async_bios allows us to reliably return congestion to the
4688          * higher layers.  Otherwise, the async bio makes it appear we have
4689          * made progress against dirty pages when we've really just put it
4690          * on a queue for later
4691          */
4692         atomic_inc(&root->fs_info->nr_async_bios);
4693         WARN_ON(bio->bi_next);
4694         bio->bi_next = NULL;
4695         bio->bi_rw |= rw;
4696
4697         spin_lock(&device->io_lock);
4698         if (bio->bi_rw & REQ_SYNC)
4699                 pending_bios = &device->pending_sync_bios;
4700         else
4701                 pending_bios = &device->pending_bios;
4702
4703         if (pending_bios->tail)
4704                 pending_bios->tail->bi_next = bio;
4705
4706         pending_bios->tail = bio;
4707         if (!pending_bios->head)
4708                 pending_bios->head = bio;
4709         if (device->running_pending)
4710                 should_queue = 0;
4711
4712         spin_unlock(&device->io_lock);
4713
4714         if (should_queue)
4715                 btrfs_queue_worker(&root->fs_info->submit_workers,
4716                                    &device->work);
4717 }
4718
4719 static int bio_size_ok(struct block_device *bdev, struct bio *bio,
4720                        sector_t sector)
4721 {
4722         struct bio_vec *prev;
4723         struct request_queue *q = bdev_get_queue(bdev);
4724         unsigned short max_sectors = queue_max_sectors(q);
4725         struct bvec_merge_data bvm = {
4726                 .bi_bdev = bdev,
4727                 .bi_sector = sector,
4728                 .bi_rw = bio->bi_rw,
4729         };
4730
4731         if (bio->bi_vcnt == 0) {
4732                 WARN_ON(1);
4733                 return 1;
4734         }
4735
4736         prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
4737         if ((bio->bi_size >> 9) > max_sectors)
4738                 return 0;
4739
4740         if (!q->merge_bvec_fn)
4741                 return 1;
4742
4743         bvm.bi_size = bio->bi_size - prev->bv_len;
4744         if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len)
4745                 return 0;
4746         return 1;
4747 }
4748
4749 static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
4750                               struct bio *bio, u64 physical, int dev_nr,
4751                               int rw, int async)
4752 {
4753         struct btrfs_device *dev = bbio->stripes[dev_nr].dev;
4754
4755         bio->bi_private = bbio;
4756         bio->bi_private = merge_stripe_index_into_bio_private(
4757                         bio->bi_private, (unsigned int)dev_nr);
4758         bio->bi_end_io = btrfs_end_bio;
4759         bio->bi_sector = physical >> 9;
4760 #ifdef DEBUG
4761         {
4762                 struct rcu_string *name;
4763
4764                 rcu_read_lock();
4765                 name = rcu_dereference(dev->name);
4766                 pr_debug("btrfs_map_bio: rw %d, sector=%llu, dev=%lu "
4767                          "(%s id %llu), size=%u\n", rw,
4768                          (u64)bio->bi_sector, (u_long)dev->bdev->bd_dev,
4769                          name->str, dev->devid, bio->bi_size);
4770                 rcu_read_unlock();
4771         }
4772 #endif
4773         bio->bi_bdev = dev->bdev;
4774         if (async)
4775                 schedule_bio(root, dev, rw, bio);
4776         else
4777                 btrfsic_submit_bio(rw, bio);
4778 }
4779
4780 static int breakup_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
4781                               struct bio *first_bio, struct btrfs_device *dev,
4782                               int dev_nr, int rw, int async)
4783 {
4784         struct bio_vec *bvec = first_bio->bi_io_vec;
4785         struct bio *bio;
4786         int nr_vecs = bio_get_nr_vecs(dev->bdev);
4787         u64 physical = bbio->stripes[dev_nr].physical;
4788
4789 again:
4790         bio = btrfs_bio_alloc(dev->bdev, physical >> 9, nr_vecs, GFP_NOFS);
4791         if (!bio)
4792                 return -ENOMEM;
4793
4794         while (bvec <= (first_bio->bi_io_vec + first_bio->bi_vcnt - 1)) {
4795                 if (bio_add_page(bio, bvec->bv_page, bvec->bv_len,
4796                                  bvec->bv_offset) < bvec->bv_len) {
4797                         u64 len = bio->bi_size;
4798
4799                         atomic_inc(&bbio->stripes_pending);
4800                         submit_stripe_bio(root, bbio, bio, physical, dev_nr,
4801                                           rw, async);
4802                         physical += len;
4803                         goto again;
4804                 }
4805                 bvec++;
4806         }
4807
4808         submit_stripe_bio(root, bbio, bio, physical, dev_nr, rw, async);
4809         return 0;
4810 }
4811
4812 static void bbio_error(struct btrfs_bio *bbio, struct bio *bio, u64 logical)
4813 {
4814         atomic_inc(&bbio->error);
4815         if (atomic_dec_and_test(&bbio->stripes_pending)) {
4816                 bio->bi_private = bbio->private;
4817                 bio->bi_end_io = bbio->end_io;
4818                 bio->bi_bdev = (struct block_device *)
4819                         (unsigned long)bbio->mirror_num;
4820                 bio->bi_sector = logical >> 9;
4821                 kfree(bbio);
4822                 bio_endio(bio, -EIO);
4823         }
4824 }
4825
4826 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
4827                   int mirror_num, int async_submit)
4828 {
4829         struct btrfs_device *dev;
4830         struct bio *first_bio = bio;
4831         u64 logical = (u64)bio->bi_sector << 9;
4832         u64 length = 0;
4833         u64 map_length;
4834         int ret;
4835         int dev_nr = 0;
4836         int total_devs = 1;
4837         struct btrfs_bio *bbio = NULL;
4838
4839         length = bio->bi_size;
4840         map_length = length;
4841
4842         ret = btrfs_map_block(root->fs_info, rw, logical, &map_length, &bbio,
4843                               mirror_num);
4844         if (ret)
4845                 return ret;
4846
4847         total_devs = bbio->num_stripes;
4848         if (map_length < length) {
4849                 printk(KERN_CRIT "btrfs: mapping failed logical %llu bio len %llu "
4850                        "len %llu\n", (unsigned long long)logical,
4851                        (unsigned long long)length,
4852                        (unsigned long long)map_length);
4853                 BUG();
4854         }
4855
4856         bbio->orig_bio = first_bio;
4857         bbio->private = first_bio->bi_private;
4858         bbio->end_io = first_bio->bi_end_io;
4859         atomic_set(&bbio->stripes_pending, bbio->num_stripes);
4860
4861         while (dev_nr < total_devs) {
4862                 dev = bbio->stripes[dev_nr].dev;
4863                 if (!dev || !dev->bdev || (rw & WRITE && !dev->writeable)) {
4864                         bbio_error(bbio, first_bio, logical);
4865                         dev_nr++;
4866                         continue;
4867                 }
4868
4869                 /*
4870                  * Check and see if we're ok with this bio based on it's size
4871                  * and offset with the given device.
4872                  */
4873                 if (!bio_size_ok(dev->bdev, first_bio,
4874                                  bbio->stripes[dev_nr].physical >> 9)) {
4875                         ret = breakup_stripe_bio(root, bbio, first_bio, dev,
4876                                                  dev_nr, rw, async_submit);
4877                         BUG_ON(ret);
4878                         dev_nr++;
4879                         continue;
4880                 }
4881
4882                 if (dev_nr < total_devs - 1) {
4883                         bio = bio_clone(first_bio, GFP_NOFS);
4884                         BUG_ON(!bio); /* -ENOMEM */
4885                 } else {
4886                         bio = first_bio;
4887                 }
4888
4889                 submit_stripe_bio(root, bbio, bio,
4890                                   bbio->stripes[dev_nr].physical, dev_nr, rw,
4891                                   async_submit);
4892                 dev_nr++;
4893         }
4894         return 0;
4895 }
4896
4897 struct btrfs_device *btrfs_find_device(struct btrfs_fs_info *fs_info, u64 devid,
4898                                        u8 *uuid, u8 *fsid)
4899 {
4900         struct btrfs_device *device;
4901         struct btrfs_fs_devices *cur_devices;
4902
4903         cur_devices = fs_info->fs_devices;
4904         while (cur_devices) {
4905                 if (!fsid ||
4906                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
4907                         device = __find_device(&cur_devices->devices,
4908                                                devid, uuid);
4909                         if (device)
4910                                 return device;
4911                 }
4912                 cur_devices = cur_devices->seed;
4913         }
4914         return NULL;
4915 }
4916
4917 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
4918                                             u64 devid, u8 *dev_uuid)
4919 {
4920         struct btrfs_device *device;
4921         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
4922
4923         device = kzalloc(sizeof(*device), GFP_NOFS);
4924         if (!device)
4925                 return NULL;
4926         list_add(&device->dev_list,
4927                  &fs_devices->devices);
4928         device->dev_root = root->fs_info->dev_root;
4929         device->devid = devid;
4930         device->work.func = pending_bios_fn;
4931         device->fs_devices = fs_devices;
4932         device->missing = 1;
4933         fs_devices->num_devices++;
4934         fs_devices->missing_devices++;
4935         spin_lock_init(&device->io_lock);
4936         INIT_LIST_HEAD(&device->dev_alloc_list);
4937         memcpy(device->uuid, dev_uuid, BTRFS_UUID_SIZE);
4938         return device;
4939 }
4940
4941 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
4942                           struct extent_buffer *leaf,
4943                           struct btrfs_chunk *chunk)
4944 {
4945         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
4946         struct map_lookup *map;
4947         struct extent_map *em;
4948         u64 logical;
4949         u64 length;
4950         u64 devid;
4951         u8 uuid[BTRFS_UUID_SIZE];
4952         int num_stripes;
4953         int ret;
4954         int i;
4955
4956         logical = key->offset;
4957         length = btrfs_chunk_length(leaf, chunk);
4958
4959         read_lock(&map_tree->map_tree.lock);
4960         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
4961         read_unlock(&map_tree->map_tree.lock);
4962
4963         /* already mapped? */
4964         if (em && em->start <= logical && em->start + em->len > logical) {
4965                 free_extent_map(em);
4966                 return 0;
4967         } else if (em) {
4968                 free_extent_map(em);
4969         }
4970
4971         em = alloc_extent_map();
4972         if (!em)
4973                 return -ENOMEM;
4974         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
4975         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
4976         if (!map) {
4977                 free_extent_map(em);
4978                 return -ENOMEM;
4979         }
4980
4981         em->bdev = (struct block_device *)map;
4982         em->start = logical;
4983         em->len = length;
4984         em->orig_start = 0;
4985         em->block_start = 0;
4986         em->block_len = em->len;
4987
4988         map->num_stripes = num_stripes;
4989         map->io_width = btrfs_chunk_io_width(leaf, chunk);
4990         map->io_align = btrfs_chunk_io_align(leaf, chunk);
4991         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
4992         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
4993         map->type = btrfs_chunk_type(leaf, chunk);
4994         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
4995         for (i = 0; i < num_stripes; i++) {
4996                 map->stripes[i].physical =
4997                         btrfs_stripe_offset_nr(leaf, chunk, i);
4998                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
4999                 read_extent_buffer(leaf, uuid, (unsigned long)
5000                                    btrfs_stripe_dev_uuid_nr(chunk, i),
5001                                    BTRFS_UUID_SIZE);
5002                 map->stripes[i].dev = btrfs_find_device(root->fs_info, devid,
5003                                                         uuid, NULL);
5004                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
5005                         kfree(map);
5006                         free_extent_map(em);
5007                         return -EIO;
5008                 }
5009                 if (!map->stripes[i].dev) {
5010                         map->stripes[i].dev =
5011                                 add_missing_dev(root, devid, uuid);
5012                         if (!map->stripes[i].dev) {
5013                                 kfree(map);
5014                                 free_extent_map(em);
5015                                 return -EIO;
5016                         }
5017                 }
5018                 map->stripes[i].dev->in_fs_metadata = 1;
5019         }
5020
5021         write_lock(&map_tree->map_tree.lock);
5022         ret = add_extent_mapping(&map_tree->map_tree, em);
5023         write_unlock(&map_tree->map_tree.lock);
5024         BUG_ON(ret); /* Tree corruption */
5025         free_extent_map(em);
5026
5027         return 0;
5028 }
5029
5030 static void fill_device_from_item(struct extent_buffer *leaf,
5031                                  struct btrfs_dev_item *dev_item,
5032                                  struct btrfs_device *device)
5033 {
5034         unsigned long ptr;
5035
5036         device->devid = btrfs_device_id(leaf, dev_item);
5037         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
5038         device->total_bytes = device->disk_total_bytes;
5039         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
5040         device->type = btrfs_device_type(leaf, dev_item);
5041         device->io_align = btrfs_device_io_align(leaf, dev_item);
5042         device->io_width = btrfs_device_io_width(leaf, dev_item);
5043         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
5044         WARN_ON(device->devid == BTRFS_DEV_REPLACE_DEVID);
5045         device->is_tgtdev_for_dev_replace = 0;
5046
5047         ptr = (unsigned long)btrfs_device_uuid(dev_item);
5048         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
5049 }
5050
5051 static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
5052 {
5053         struct btrfs_fs_devices *fs_devices;
5054         int ret;
5055
5056         BUG_ON(!mutex_is_locked(&uuid_mutex));
5057
5058         fs_devices = root->fs_info->fs_devices->seed;
5059         while (fs_devices) {
5060                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
5061                         ret = 0;
5062                         goto out;
5063                 }
5064                 fs_devices = fs_devices->seed;
5065         }
5066
5067         fs_devices = find_fsid(fsid);
5068         if (!fs_devices) {
5069                 ret = -ENOENT;
5070                 goto out;
5071         }
5072
5073         fs_devices = clone_fs_devices(fs_devices);
5074         if (IS_ERR(fs_devices)) {
5075                 ret = PTR_ERR(fs_devices);
5076                 goto out;
5077         }
5078
5079         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
5080                                    root->fs_info->bdev_holder);
5081         if (ret) {
5082                 free_fs_devices(fs_devices);
5083                 goto out;
5084         }
5085
5086         if (!fs_devices->seeding) {
5087                 __btrfs_close_devices(fs_devices);
5088                 free_fs_devices(fs_devices);
5089                 ret = -EINVAL;
5090                 goto out;
5091         }
5092
5093         fs_devices->seed = root->fs_info->fs_devices->seed;
5094         root->fs_info->fs_devices->seed = fs_devices;
5095 out:
5096         return ret;
5097 }
5098
5099 static int read_one_dev(struct btrfs_root *root,
5100                         struct extent_buffer *leaf,
5101                         struct btrfs_dev_item *dev_item)
5102 {
5103         struct btrfs_device *device;
5104         u64 devid;
5105         int ret;
5106         u8 fs_uuid[BTRFS_UUID_SIZE];
5107         u8 dev_uuid[BTRFS_UUID_SIZE];
5108
5109         devid = btrfs_device_id(leaf, dev_item);
5110         read_extent_buffer(leaf, dev_uuid,
5111                            (unsigned long)btrfs_device_uuid(dev_item),
5112                            BTRFS_UUID_SIZE);
5113         read_extent_buffer(leaf, fs_uuid,
5114                            (unsigned long)btrfs_device_fsid(dev_item),
5115                            BTRFS_UUID_SIZE);
5116
5117         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
5118                 ret = open_seed_devices(root, fs_uuid);
5119                 if (ret && !btrfs_test_opt(root, DEGRADED))
5120                         return ret;
5121         }
5122
5123         device = btrfs_find_device(root->fs_info, devid, dev_uuid, fs_uuid);
5124         if (!device || !device->bdev) {
5125                 if (!btrfs_test_opt(root, DEGRADED))
5126                         return -EIO;
5127
5128                 if (!device) {
5129                         printk(KERN_WARNING "warning devid %llu missing\n",
5130                                (unsigned long long)devid);
5131                         device = add_missing_dev(root, devid, dev_uuid);
5132                         if (!device)
5133                                 return -ENOMEM;
5134                 } else if (!device->missing) {
5135                         /*
5136                          * this happens when a device that was properly setup
5137                          * in the device info lists suddenly goes bad.
5138                          * device->bdev is NULL, and so we have to set
5139                          * device->missing to one here
5140                          */
5141                         root->fs_info->fs_devices->missing_devices++;
5142                         device->missing = 1;
5143                 }
5144         }
5145
5146         if (device->fs_devices != root->fs_info->fs_devices) {
5147                 BUG_ON(device->writeable);
5148                 if (device->generation !=
5149                     btrfs_device_generation(leaf, dev_item))
5150                         return -EINVAL;
5151         }
5152
5153         fill_device_from_item(leaf, dev_item, device);
5154         device->dev_root = root->fs_info->dev_root;
5155         device->in_fs_metadata = 1;
5156         if (device->writeable && !device->is_tgtdev_for_dev_replace) {
5157                 device->fs_devices->total_rw_bytes += device->total_bytes;
5158                 spin_lock(&root->fs_info->free_chunk_lock);
5159                 root->fs_info->free_chunk_space += device->total_bytes -
5160                         device->bytes_used;
5161                 spin_unlock(&root->fs_info->free_chunk_lock);
5162         }
5163         ret = 0;
5164         return ret;
5165 }
5166
5167 int btrfs_read_sys_array(struct btrfs_root *root)
5168 {
5169         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
5170         struct extent_buffer *sb;
5171         struct btrfs_disk_key *disk_key;
5172         struct btrfs_chunk *chunk;
5173         u8 *ptr;
5174         unsigned long sb_ptr;
5175         int ret = 0;
5176         u32 num_stripes;
5177         u32 array_size;
5178         u32 len = 0;
5179         u32 cur;
5180         struct btrfs_key key;
5181
5182         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
5183                                           BTRFS_SUPER_INFO_SIZE);
5184         if (!sb)
5185                 return -ENOMEM;
5186         btrfs_set_buffer_uptodate(sb);
5187         btrfs_set_buffer_lockdep_class(root->root_key.objectid, sb, 0);
5188         /*
5189          * The sb extent buffer is artifical and just used to read the system array.
5190          * btrfs_set_buffer_uptodate() call does not properly mark all it's
5191          * pages up-to-date when the page is larger: extent does not cover the
5192          * whole page and consequently check_page_uptodate does not find all
5193          * the page's extents up-to-date (the hole beyond sb),
5194          * write_extent_buffer then triggers a WARN_ON.
5195          *
5196          * Regular short extents go through mark_extent_buffer_dirty/writeback cycle,
5197          * but sb spans only this function. Add an explicit SetPageUptodate call
5198          * to silence the warning eg. on PowerPC 64.
5199          */
5200         if (PAGE_CACHE_SIZE > BTRFS_SUPER_INFO_SIZE)
5201                 SetPageUptodate(sb->pages[0]);
5202
5203         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
5204         array_size = btrfs_super_sys_array_size(super_copy);
5205
5206         ptr = super_copy->sys_chunk_array;
5207         sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
5208         cur = 0;
5209
5210         while (cur < array_size) {
5211                 disk_key = (struct btrfs_disk_key *)ptr;
5212                 btrfs_disk_key_to_cpu(&key, disk_key);
5213
5214                 len = sizeof(*disk_key); ptr += len;
5215                 sb_ptr += len;
5216                 cur += len;
5217
5218                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
5219                         chunk = (struct btrfs_chunk *)sb_ptr;
5220                         ret = read_one_chunk(root, &key, sb, chunk);
5221                         if (ret)
5222                                 break;
5223                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
5224                         len = btrfs_chunk_item_size(num_stripes);
5225                 } else {
5226                         ret = -EIO;
5227                         break;
5228                 }
5229                 ptr += len;
5230                 sb_ptr += len;
5231                 cur += len;
5232         }
5233         free_extent_buffer(sb);
5234         return ret;
5235 }
5236
5237 int btrfs_read_chunk_tree(struct btrfs_root *root)
5238 {
5239         struct btrfs_path *path;
5240         struct extent_buffer *leaf;
5241         struct btrfs_key key;
5242         struct btrfs_key found_key;
5243         int ret;
5244         int slot;
5245
5246         root = root->fs_info->chunk_root;
5247
5248         path = btrfs_alloc_path();
5249         if (!path)
5250                 return -ENOMEM;
5251
5252         mutex_lock(&uuid_mutex);
5253         lock_chunks(root);
5254
5255         /* first we search for all of the device items, and then we
5256          * read in all of the chunk items.  This way we can create chunk
5257          * mappings that reference all of the devices that are afound
5258          */
5259         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
5260         key.offset = 0;
5261         key.type = 0;
5262 again:
5263         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5264         if (ret < 0)
5265                 goto error;
5266         while (1) {
5267                 leaf = path->nodes[0];
5268                 slot = path->slots[0];
5269                 if (slot >= btrfs_header_nritems(leaf)) {
5270                         ret = btrfs_next_leaf(root, path);
5271                         if (ret == 0)
5272                                 continue;
5273                         if (ret < 0)
5274                                 goto error;
5275                         break;
5276                 }
5277                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5278                 if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
5279                         if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
5280                                 break;
5281                         if (found_key.type == BTRFS_DEV_ITEM_KEY) {
5282                                 struct btrfs_dev_item *dev_item;
5283                                 dev_item = btrfs_item_ptr(leaf, slot,
5284                                                   struct btrfs_dev_item);
5285                                 ret = read_one_dev(root, leaf, dev_item);
5286                                 if (ret)
5287                                         goto error;
5288                         }
5289                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
5290                         struct btrfs_chunk *chunk;
5291                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
5292                         ret = read_one_chunk(root, &found_key, leaf, chunk);
5293                         if (ret)
5294                                 goto error;
5295                 }
5296                 path->slots[0]++;
5297         }
5298         if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
5299                 key.objectid = 0;
5300                 btrfs_release_path(path);
5301                 goto again;
5302         }
5303         ret = 0;
5304 error:
5305         unlock_chunks(root);
5306         mutex_unlock(&uuid_mutex);
5307
5308         btrfs_free_path(path);
5309         return ret;
5310 }
5311
5312 static void __btrfs_reset_dev_stats(struct btrfs_device *dev)
5313 {
5314         int i;
5315
5316         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5317                 btrfs_dev_stat_reset(dev, i);
5318 }
5319
5320 int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info)
5321 {
5322         struct btrfs_key key;
5323         struct btrfs_key found_key;
5324         struct btrfs_root *dev_root = fs_info->dev_root;
5325         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
5326         struct extent_buffer *eb;
5327         int slot;
5328         int ret = 0;
5329         struct btrfs_device *device;
5330         struct btrfs_path *path = NULL;
5331         int i;
5332
5333         path = btrfs_alloc_path();
5334         if (!path) {
5335                 ret = -ENOMEM;
5336                 goto out;
5337         }
5338
5339         mutex_lock(&fs_devices->device_list_mutex);
5340         list_for_each_entry(device, &fs_devices->devices, dev_list) {
5341                 int item_size;
5342                 struct btrfs_dev_stats_item *ptr;
5343
5344                 key.objectid = 0;
5345                 key.type = BTRFS_DEV_STATS_KEY;
5346                 key.offset = device->devid;
5347                 ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
5348                 if (ret) {
5349                         __btrfs_reset_dev_stats(device);
5350                         device->dev_stats_valid = 1;
5351                         btrfs_release_path(path);
5352                         continue;
5353                 }
5354                 slot = path->slots[0];
5355                 eb = path->nodes[0];
5356                 btrfs_item_key_to_cpu(eb, &found_key, slot);
5357                 item_size = btrfs_item_size_nr(eb, slot);
5358
5359                 ptr = btrfs_item_ptr(eb, slot,
5360                                      struct btrfs_dev_stats_item);
5361
5362                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
5363                         if (item_size >= (1 + i) * sizeof(__le64))
5364                                 btrfs_dev_stat_set(device, i,
5365                                         btrfs_dev_stats_value(eb, ptr, i));
5366                         else
5367                                 btrfs_dev_stat_reset(device, i);
5368                 }
5369
5370                 device->dev_stats_valid = 1;
5371                 btrfs_dev_stat_print_on_load(device);
5372                 btrfs_release_path(path);
5373         }
5374         mutex_unlock(&fs_devices->device_list_mutex);
5375
5376 out:
5377         btrfs_free_path(path);
5378         return ret < 0 ? ret : 0;
5379 }
5380
5381 static int update_dev_stat_item(struct btrfs_trans_handle *trans,
5382                                 struct btrfs_root *dev_root,
5383                                 struct btrfs_device *device)
5384 {
5385         struct btrfs_path *path;
5386         struct btrfs_key key;
5387         struct extent_buffer *eb;
5388         struct btrfs_dev_stats_item *ptr;
5389         int ret;
5390         int i;
5391
5392         key.objectid = 0;
5393         key.type = BTRFS_DEV_STATS_KEY;
5394         key.offset = device->devid;
5395
5396         path = btrfs_alloc_path();
5397         BUG_ON(!path);
5398         ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
5399         if (ret < 0) {
5400                 printk_in_rcu(KERN_WARNING "btrfs: error %d while searching for dev_stats item for device %s!\n",
5401                               ret, rcu_str_deref(device->name));
5402                 goto out;
5403         }
5404
5405         if (ret == 0 &&
5406             btrfs_item_size_nr(path->nodes[0], path->slots[0]) < sizeof(*ptr)) {
5407                 /* need to delete old one and insert a new one */
5408                 ret = btrfs_del_item(trans, dev_root, path);
5409                 if (ret != 0) {
5410                         printk_in_rcu(KERN_WARNING "btrfs: delete too small dev_stats item for device %s failed %d!\n",
5411                                       rcu_str_deref(device->name), ret);
5412                         goto out;
5413                 }
5414                 ret = 1;
5415         }
5416
5417         if (ret == 1) {
5418                 /* need to insert a new item */
5419                 btrfs_release_path(path);
5420                 ret = btrfs_insert_empty_item(trans, dev_root, path,
5421                                               &key, sizeof(*ptr));
5422                 if (ret < 0) {
5423                         printk_in_rcu(KERN_WARNING "btrfs: insert dev_stats item for device %s failed %d!\n",
5424                                       rcu_str_deref(device->name), ret);
5425                         goto out;
5426                 }
5427         }
5428
5429         eb = path->nodes[0];
5430         ptr = btrfs_item_ptr(eb, path->slots[0], struct btrfs_dev_stats_item);
5431         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5432                 btrfs_set_dev_stats_value(eb, ptr, i,
5433                                           btrfs_dev_stat_read(device, i));
5434         btrfs_mark_buffer_dirty(eb);
5435
5436 out:
5437         btrfs_free_path(path);
5438         return ret;
5439 }
5440
5441 /*
5442  * called from commit_transaction. Writes all changed device stats to disk.
5443  */
5444 int btrfs_run_dev_stats(struct btrfs_trans_handle *trans,
5445                         struct btrfs_fs_info *fs_info)
5446 {
5447         struct btrfs_root *dev_root = fs_info->dev_root;
5448         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
5449         struct btrfs_device *device;
5450         int ret = 0;
5451
5452         mutex_lock(&fs_devices->device_list_mutex);
5453         list_for_each_entry(device, &fs_devices->devices, dev_list) {
5454                 if (!device->dev_stats_valid || !device->dev_stats_dirty)
5455                         continue;
5456
5457                 ret = update_dev_stat_item(trans, dev_root, device);
5458                 if (!ret)
5459                         device->dev_stats_dirty = 0;
5460         }
5461         mutex_unlock(&fs_devices->device_list_mutex);
5462
5463         return ret;
5464 }
5465
5466 void btrfs_dev_stat_inc_and_print(struct btrfs_device *dev, int index)
5467 {
5468         btrfs_dev_stat_inc(dev, index);
5469         btrfs_dev_stat_print_on_error(dev);
5470 }
5471
5472 void btrfs_dev_stat_print_on_error(struct btrfs_device *dev)
5473 {
5474         if (!dev->dev_stats_valid)
5475                 return;
5476         printk_ratelimited_in_rcu(KERN_ERR
5477                            "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
5478                            rcu_str_deref(dev->name),
5479                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
5480                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
5481                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
5482                            btrfs_dev_stat_read(dev,
5483                                                BTRFS_DEV_STAT_CORRUPTION_ERRS),
5484                            btrfs_dev_stat_read(dev,
5485                                                BTRFS_DEV_STAT_GENERATION_ERRS));
5486 }
5487
5488 static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
5489 {
5490         int i;
5491
5492         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5493                 if (btrfs_dev_stat_read(dev, i) != 0)
5494                         break;
5495         if (i == BTRFS_DEV_STAT_VALUES_MAX)
5496                 return; /* all values == 0, suppress message */
5497
5498         printk_in_rcu(KERN_INFO "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
5499                rcu_str_deref(dev->name),
5500                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
5501                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
5502                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
5503                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
5504                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
5505 }
5506
5507 int btrfs_get_dev_stats(struct btrfs_root *root,
5508                         struct btrfs_ioctl_get_dev_stats *stats)
5509 {
5510         struct btrfs_device *dev;
5511         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
5512         int i;
5513
5514         mutex_lock(&fs_devices->device_list_mutex);
5515         dev = btrfs_find_device(root->fs_info, stats->devid, NULL, NULL);
5516         mutex_unlock(&fs_devices->device_list_mutex);
5517
5518         if (!dev) {
5519                 printk(KERN_WARNING
5520                        "btrfs: get dev_stats failed, device not found\n");
5521                 return -ENODEV;
5522         } else if (!dev->dev_stats_valid) {
5523                 printk(KERN_WARNING
5524                        "btrfs: get dev_stats failed, not yet valid\n");
5525                 return -ENODEV;
5526         } else if (stats->flags & BTRFS_DEV_STATS_RESET) {
5527                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
5528                         if (stats->nr_items > i)
5529                                 stats->values[i] =
5530                                         btrfs_dev_stat_read_and_reset(dev, i);
5531                         else
5532                                 btrfs_dev_stat_reset(dev, i);
5533                 }
5534         } else {
5535                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5536                         if (stats->nr_items > i)
5537                                 stats->values[i] = btrfs_dev_stat_read(dev, i);
5538         }
5539         if (stats->nr_items > BTRFS_DEV_STAT_VALUES_MAX)
5540                 stats->nr_items = BTRFS_DEV_STAT_VALUES_MAX;
5541         return 0;
5542 }
5543
5544 int btrfs_scratch_superblock(struct btrfs_device *device)
5545 {
5546         struct buffer_head *bh;
5547         struct btrfs_super_block *disk_super;
5548
5549         bh = btrfs_read_dev_super(device->bdev);
5550         if (!bh)
5551                 return -EINVAL;
5552         disk_super = (struct btrfs_super_block *)bh->b_data;
5553
5554         memset(&disk_super->magic, 0, sizeof(disk_super->magic));
5555         set_buffer_dirty(bh);
5556         sync_dirty_buffer(bh);
5557         brelse(bh);
5558
5559         return 0;
5560 }