drivers/target/target_core_file.c

   1 /*******************************************************************************
   2  * Filename:  target_core_file.c
   3  *
   4  * This file contains the Storage Engine <-> FILEIO transport specific functions
   5  *
   6  * (c) Copyright 2005-2012 RisingTide Systems LLC.
   7  *
   8  * Nicholas A. Bellinger <nab@kernel.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  23  *
  24  ******************************************************************************/
  25
  26 #include <linux/string.h>
  27 #include <linux/parser.h>
  28 #include <linux/timer.h>
  29 #include <linux/blkdev.h>
  30 #include <linux/slab.h>
  31 #include <linux/spinlock.h>
  32 #include <linux/module.h>
  33 #include <scsi/scsi.h>
  34 #include <scsi/scsi_host.h>
  35
  36 #include <target/target_core_base.h>
  37 #include <target/target_core_backend.h>
  38
  39 #include "target_core_file.h"
  40
  41 static inline struct fd_dev *FD_DEV(struct se_device *dev)
  42 {
  43         return container_of(dev, struct fd_dev, dev);
  44 }
  45
  46 /*      fd_attach_hba(): (Part of se_subsystem_api_t template)
  47  *
  48  *
  49  */
  50 static int fd_attach_hba(struct se_hba *hba, u32 host_id)
  51 {
  52         struct fd_host *fd_host;
  53
  54         fd_host = kzalloc(sizeof(struct fd_host), GFP_KERNEL);
  55         if (!fd_host) {
  56                 pr_err("Unable to allocate memory for struct fd_host\n");
  57                 return -ENOMEM;
  58         }
  59
  60         fd_host->fd_host_id = host_id;
  61
  62         hba->hba_ptr = fd_host;
  63
  64         pr_debug("CORE_HBA[%d] - TCM FILEIO HBA Driver %s on Generic"
  65                 " Target Core Stack %s\n", hba->hba_id, FD_VERSION,
  66                 TARGET_CORE_MOD_VERSION);
  67         pr_debug("CORE_HBA[%d] - Attached FILEIO HBA: %u to Generic"
  68                 " MaxSectors: %u\n",
  69                 hba->hba_id, fd_host->fd_host_id, FD_MAX_SECTORS);
  70
  71         return 0;
  72 }
  73
  74 static void fd_detach_hba(struct se_hba *hba)
  75 {
  76         struct fd_host *fd_host = hba->hba_ptr;
  77
  78         pr_debug("CORE_HBA[%d] - Detached FILEIO HBA: %u from Generic"
  79                 " Target Core\n", hba->hba_id, fd_host->fd_host_id);
  80
  81         kfree(fd_host);
  82         hba->hba_ptr = NULL;
  83 }
  84
  85 static struct se_device *fd_alloc_device(struct se_hba *hba, const char *name)
  86 {
  87         struct fd_dev *fd_dev;
  88         struct fd_host *fd_host = hba->hba_ptr;
  89
  90         fd_dev = kzalloc(sizeof(struct fd_dev), GFP_KERNEL);
  91         if (!fd_dev) {
  92                 pr_err("Unable to allocate memory for struct fd_dev\n");
  93                 return NULL;
  94         }
  95
  96         fd_dev->fd_host = fd_host;
  97
  98         pr_debug("FILEIO: Allocated fd_dev for %p\n", name);
  99
 100         return &fd_dev->dev;
 101 }
 102
 103 static int fd_configure_device(struct se_device *dev)
 104 {
 105         struct fd_dev *fd_dev = FD_DEV(dev);
 106         struct fd_host *fd_host = dev->se_hba->hba_ptr;
 107         struct file *file;
 108         struct inode *inode = NULL;
 109         int flags, ret = -EINVAL;
 110
 111         if (!(fd_dev->fbd_flags & FBDF_HAS_PATH)) {
 112                 pr_err("Missing fd_dev_name=\n");
 113                 return -EINVAL;
 114         }
 115
 116         /*
 117          * Use O_DSYNC by default instead of O_SYNC to forgo syncing
 118          * of pure timestamp updates.
 119          */
 120         flags = O_RDWR | O_CREAT | O_LARGEFILE | O_DSYNC;
 121
 122         /*
 123          * Optionally allow fd_buffered_io=1 to be enabled for people
 124          * who want use the fs buffer cache as an WriteCache mechanism.
 125          *
 126          * This means that in event of a hard failure, there is a risk
 127          * of silent data-loss if the SCSI client has *not* performed a
 128          * forced unit access (FUA) write, or issued SYNCHRONIZE_CACHE
 129          * to write-out the entire device cache.
 130          */
 131         if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) {
 132                 pr_debug("FILEIO: Disabling O_DSYNC, using buffered FILEIO\n");
 133                 flags &= ~O_DSYNC;
 134         }
 135
 136         file = filp_open(fd_dev->fd_dev_name, flags, 0600);
 137         if (IS_ERR(file)) {
 138                 pr_err("filp_open(%s) failed\n", fd_dev->fd_dev_name);
 139                 ret = PTR_ERR(file);
 140                 goto fail;
 141         }
 142         fd_dev->fd_file = file;
 143         /*
 144          * If using a block backend with this struct file, we extract
 145          * fd_dev->fd_[block,dev]_size from struct block_device.
 146          *
 147          * Otherwise, we use the passed fd_size= from configfs
 148          */
 149         inode = file->f_mapping->host;
 150         if (S_ISBLK(inode->i_mode)) {
 151                 struct request_queue *q = bdev_get_queue(inode->i_bdev);
 152                 unsigned long long dev_size;
 153
 154                 dev->dev_attrib.hw_block_size =
 155                         bdev_logical_block_size(inode->i_bdev);
 156                 dev->dev_attrib.hw_max_sectors = queue_max_hw_sectors(q);
 157
 158                 /*
 159                  * Determine the number of bytes from i_size_read() minus
 160                  * one (1) logical sector from underlying struct block_device
 161                  */
 162                 dev_size = (i_size_read(file->f_mapping->host) -
 163                                        fd_dev->fd_block_size);
 164
 165                 pr_debug("FILEIO: Using size: %llu bytes from struct"
 166                         " block_device blocks: %llu logical_block_size: %d\n",
 167                         dev_size, div_u64(dev_size, fd_dev->fd_block_size),
 168                         fd_dev->fd_block_size);
 169         } else {
 170                 if (!(fd_dev->fbd_flags & FBDF_HAS_SIZE)) {
 171                         pr_err("FILEIO: Missing fd_dev_size="
 172                                 " parameter, and no backing struct"
 173                                 " block_device\n");
 174                         goto fail;
 175                 }
 176
 177                 dev->dev_attrib.hw_block_size = FD_BLOCKSIZE;
 178                 dev->dev_attrib.hw_max_sectors = FD_MAX_SECTORS;
 179         }
 180
 181         fd_dev->fd_block_size = dev->dev_attrib.hw_block_size;
 182
 183         dev->dev_attrib.hw_queue_depth = FD_MAX_DEVICE_QUEUE_DEPTH;
 184
 185         if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) {
 186                 pr_debug("FILEIO: Forcing setting of emulate_write_cache=1"
 187                         " with FDBD_HAS_BUFFERED_IO_WCE\n");
 188                 dev->dev_attrib.emulate_write_cache = 1;
 189         }
 190
 191         fd_dev->fd_dev_id = fd_host->fd_host_dev_id_count++;
 192         fd_dev->fd_queue_depth = dev->queue_depth;
 193
 194         pr_debug("CORE_FILE[%u] - Added TCM FILEIO Device ID: %u at %s,"
 195                 " %llu total bytes\n", fd_host->fd_host_id, fd_dev->fd_dev_id,
 196                         fd_dev->fd_dev_name, fd_dev->fd_dev_size);
 197
 198         return 0;
 199 fail:
 200         if (fd_dev->fd_file) {
 201                 filp_close(fd_dev->fd_file, NULL);
 202                 fd_dev->fd_file = NULL;
 203         }
 204         return ret;
 205 }
 206
 207 static void fd_free_device(struct se_device *dev)
 208 {
 209         struct fd_dev *fd_dev = FD_DEV(dev);
 210
 211         if (fd_dev->fd_file) {
 212                 filp_close(fd_dev->fd_file, NULL);
 213                 fd_dev->fd_file = NULL;
 214         }
 215
 216         kfree(fd_dev);
 217 }
 218
 219 static int fd_do_readv(struct se_cmd *cmd, struct scatterlist *sgl,
 220                 u32 sgl_nents)
 221 {
 222         struct se_device *se_dev = cmd->se_dev;
 223         struct fd_dev *dev = FD_DEV(se_dev);
 224         struct file *fd = dev->fd_file;
 225         struct scatterlist *sg;
 226         struct iovec *iov;
 227         mm_segment_t old_fs;
 228         loff_t pos = (cmd->t_task_lba * se_dev->dev_attrib.block_size);
 229         int ret = 0, i;
 230
 231         iov = kzalloc(sizeof(struct iovec) * sgl_nents, GFP_KERNEL);
 232         if (!iov) {
 233                 pr_err("Unable to allocate fd_do_readv iov[]\n");
 234                 return -ENOMEM;
 235         }
 236
 237         for_each_sg(sgl, sg, sgl_nents, i) {
 238                 iov[i].iov_len = sg->length;
 239                 iov[i].iov_base = sg_virt(sg);
 240         }
 241
 242         old_fs = get_fs();
 243         set_fs(get_ds());
 244         ret = vfs_readv(fd, &iov[0], sgl_nents, &pos);
 245         set_fs(old_fs);
 246
 247         kfree(iov);
 248         /*
 249          * Return zeros and GOOD status even if the READ did not return
 250          * the expected virt_size for struct file w/o a backing struct
 251          * block_device.
 252          */
 253         if (S_ISBLK(fd->f_dentry->d_inode->i_mode)) {
 254                 if (ret < 0 || ret != cmd->data_length) {
 255                         pr_err("vfs_readv() returned %d,"
 256                                 " expecting %d for S_ISBLK\n", ret,
 257                                 (int)cmd->data_length);
 258                         return (ret < 0 ? ret : -EINVAL);
 259                 }
 260         } else {
 261                 if (ret < 0) {
 262                         pr_err("vfs_readv() returned %d for non"
 263                                 " S_ISBLK\n", ret);
 264                         return ret;
 265                 }
 266         }
 267
 268         return 1;
 269 }
 270
 271 static int fd_do_writev(struct se_cmd *cmd, struct scatterlist *sgl,
 272                 u32 sgl_nents)
 273 {
 274         struct se_device *se_dev = cmd->se_dev;
 275         struct fd_dev *dev = FD_DEV(se_dev);
 276         struct file *fd = dev->fd_file;
 277         struct scatterlist *sg;
 278         struct iovec *iov;
 279         mm_segment_t old_fs;
 280         loff_t pos = (cmd->t_task_lba * se_dev->dev_attrib.block_size);
 281         int ret, i = 0;
 282
 283         iov = kzalloc(sizeof(struct iovec) * sgl_nents, GFP_KERNEL);
 284         if (!iov) {
 285                 pr_err("Unable to allocate fd_do_writev iov[]\n");
 286                 return -ENOMEM;
 287         }
 288
 289         for_each_sg(sgl, sg, sgl_nents, i) {
 290                 iov[i].iov_len = sg->length;
 291                 iov[i].iov_base = sg_virt(sg);
 292         }
 293
 294         old_fs = get_fs();
 295         set_fs(get_ds());
 296         ret = vfs_writev(fd, &iov[0], sgl_nents, &pos);
 297         set_fs(old_fs);
 298
 299         kfree(iov);
 300
 301         if (ret < 0 || ret != cmd->data_length) {
 302                 pr_err("vfs_writev() returned %d\n", ret);
 303                 return (ret < 0 ? ret : -EINVAL);
 304         }
 305
 306         return 1;
 307 }
 308
 309 static sense_reason_t
 310 fd_execute_sync_cache(struct se_cmd *cmd)
 311 {
 312         struct se_device *dev = cmd->se_dev;
 313         struct fd_dev *fd_dev = FD_DEV(dev);
 314         int immed = (cmd->t_task_cdb[1] & 0x2);
 315         loff_t start, end;
 316         int ret;
 317
 318         /*
 319          * If the Immediate bit is set, queue up the GOOD response
 320          * for this SYNCHRONIZE_CACHE op
 321          */
 322         if (immed)
 323                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 324
 325         /*
 326          * Determine if we will be flushing the entire device.
 327          */
 328         if (cmd->t_task_lba == 0 && cmd->data_length == 0) {
 329                 start = 0;
 330                 end = LLONG_MAX;
 331         } else {
 332                 start = cmd->t_task_lba * dev->dev_attrib.block_size;
 333                 if (cmd->data_length)
 334                         end = start + cmd->data_length;
 335                 else
 336                         end = LLONG_MAX;
 337         }
 338
 339         ret = vfs_fsync_range(fd_dev->fd_file, start, end, 1);
 340         if (ret != 0)
 341                 pr_err("FILEIO: vfs_fsync_range() failed: %d\n", ret);
 342
 343         if (immed)
 344                 return 0;
 345
 346         if (ret)
 347                 target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
 348         else
 349                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 350
 351         return 0;
 352 }
 353
 354 static sense_reason_t
 355 fd_execute_rw(struct se_cmd *cmd)
 356 {
 357         struct scatterlist *sgl = cmd->t_data_sg;
 358         u32 sgl_nents = cmd->t_data_nents;
 359         enum dma_data_direction data_direction = cmd->data_direction;
 360         struct se_device *dev = cmd->se_dev;
 361         int ret = 0;
 362
 363         /*
 364          * Call vectorized fileio functions to map struct scatterlist
 365          * physical memory addresses to struct iovec virtual memory.
 366          */
 367         if (data_direction == DMA_FROM_DEVICE) {
 368                 ret = fd_do_readv(cmd, sgl, sgl_nents);
 369         } else {
 370                 ret = fd_do_writev(cmd, sgl, sgl_nents);
 371                 /*
 372                  * Perform implict vfs_fsync_range() for fd_do_writev() ops
 373                  * for SCSI WRITEs with Forced Unit Access (FUA) set.
 374                  * Allow this to happen independent of WCE=0 setting.
 375                  */
 376                 if (ret > 0 &&
 377                     dev->dev_attrib.emulate_fua_write > 0 &&
 378                     (cmd->se_cmd_flags & SCF_FUA)) {
 379                         struct fd_dev *fd_dev = FD_DEV(dev);
 380                         loff_t start = cmd->t_task_lba *
 381                                 dev->dev_attrib.block_size;
 382                         loff_t end = start + cmd->data_length;
 383
 384                         vfs_fsync_range(fd_dev->fd_file, start, end, 1);
 385                 }
 386         }
 387
 388         if (ret < 0)
 389                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 390
 391         if (ret)
 392                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 393         return 0;
 394 }
 395
 396 enum {
 397         Opt_fd_dev_name, Opt_fd_dev_size, Opt_fd_buffered_io, Opt_err
 398 };
 399
 400 static match_table_t tokens = {
 401         {Opt_fd_dev_name, "fd_dev_name=%s"},
 402         {Opt_fd_dev_size, "fd_dev_size=%s"},
 403         {Opt_fd_buffered_io, "fd_buffered_io=%d"},
 404         {Opt_err, NULL}
 405 };
 406
 407 static ssize_t fd_set_configfs_dev_params(struct se_device *dev,
 408                 const char *page, ssize_t count)
 409 {
 410         struct fd_dev *fd_dev = FD_DEV(dev);
 411         char *orig, *ptr, *arg_p, *opts;
 412         substring_t args[MAX_OPT_ARGS];
 413         int ret = 0, arg, token;
 414
 415         opts = kstrdup(page, GFP_KERNEL);
 416         if (!opts)
 417                 return -ENOMEM;
 418
 419         orig = opts;
 420
 421         while ((ptr = strsep(&opts, ",\n")) != NULL) {
 422                 if (!*ptr)
 423                         continue;
 424
 425                 token = match_token(ptr, tokens, args);
 426                 switch (token) {
 427                 case Opt_fd_dev_name:
 428                         if (match_strlcpy(fd_dev->fd_dev_name, &args[0],
 429                                 FD_MAX_DEV_NAME) == 0) {
 430                                 ret = -EINVAL;
 431                                 break;
 432                         }
 433                         pr_debug("FILEIO: Referencing Path: %s\n",
 434                                         fd_dev->fd_dev_name);
 435                         fd_dev->fbd_flags |= FBDF_HAS_PATH;
 436                         break;
 437                 case Opt_fd_dev_size:
 438                         arg_p = match_strdup(&args[0]);
 439                         if (!arg_p) {
 440                                 ret = -ENOMEM;
 441                                 break;
 442                         }
 443                         ret = strict_strtoull(arg_p, 0, &fd_dev->fd_dev_size);
 444                         kfree(arg_p);
 445                         if (ret < 0) {
 446                                 pr_err("strict_strtoull() failed for"
 447                                                 " fd_dev_size=\n");
 448                                 goto out;
 449                         }
 450                         pr_debug("FILEIO: Referencing Size: %llu"
 451                                         " bytes\n", fd_dev->fd_dev_size);
 452                         fd_dev->fbd_flags |= FBDF_HAS_SIZE;
 453                         break;
 454                 case Opt_fd_buffered_io:
 455                         match_int(args, &arg);
 456                         if (arg != 1) {
 457                                 pr_err("bogus fd_buffered_io=%d value\n", arg);
 458                                 ret = -EINVAL;
 459                                 goto out;
 460                         }
 461
 462                         pr_debug("FILEIO: Using buffered I/O"
 463                                 " operations for struct fd_dev\n");
 464
 465                         fd_dev->fbd_flags |= FDBD_HAS_BUFFERED_IO_WCE;
 466                         break;
 467                 default:
 468                         break;
 469                 }
 470         }
 471
 472 out:
 473         kfree(orig);
 474         return (!ret) ? count : ret;
 475 }
 476
 477 static ssize_t fd_show_configfs_dev_params(struct se_device *dev, char *b)
 478 {
 479         struct fd_dev *fd_dev = FD_DEV(dev);
 480         ssize_t bl = 0;
 481
 482         bl = sprintf(b + bl, "TCM FILEIO ID: %u", fd_dev->fd_dev_id);
 483         bl += sprintf(b + bl, "        File: %s  Size: %llu  Mode: %s\n",
 484                 fd_dev->fd_dev_name, fd_dev->fd_dev_size,
 485                 (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) ?
 486                 "Buffered-WCE" : "O_DSYNC");
 487         return bl;
 488 }
 489
 490 static sector_t fd_get_blocks(struct se_device *dev)
 491 {
 492         struct fd_dev *fd_dev = FD_DEV(dev);
 493         struct file *f = fd_dev->fd_file;
 494         struct inode *i = f->f_mapping->host;
 495         unsigned long long dev_size;
 496         /*
 497          * When using a file that references an underlying struct block_device,
 498          * ensure dev_size is always based on the current inode size in order
 499          * to handle underlying block_device resize operations.
 500          */
 501         if (S_ISBLK(i->i_mode))
 502                 dev_size = (i_size_read(i) - fd_dev->fd_block_size);
 503         else
 504                 dev_size = fd_dev->fd_dev_size;
 505
 506         return div_u64(dev_size, dev->dev_attrib.block_size);
 507 }
 508
 509 static struct sbc_ops fd_sbc_ops = {
 510         .execute_rw             = fd_execute_rw,
 511         .execute_sync_cache     = fd_execute_sync_cache,
 512 };
 513
 514 static sense_reason_t
 515 fd_parse_cdb(struct se_cmd *cmd)
 516 {
 517         return sbc_parse_cdb(cmd, &fd_sbc_ops);
 518 }
 519
 520 static struct se_subsystem_api fileio_template = {
 521         .name                   = "fileio",
 522         .inquiry_prod           = "FILEIO",
 523         .inquiry_rev            = FD_VERSION,
 524         .owner                  = THIS_MODULE,
 525         .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
 526         .attach_hba             = fd_attach_hba,
 527         .detach_hba             = fd_detach_hba,
 528         .alloc_device           = fd_alloc_device,
 529         .configure_device       = fd_configure_device,
 530         .free_device            = fd_free_device,
 531         .parse_cdb              = fd_parse_cdb,
 532         .set_configfs_dev_params = fd_set_configfs_dev_params,
 533         .show_configfs_dev_params = fd_show_configfs_dev_params,
 534         .get_device_type        = sbc_get_device_type,
 535         .get_blocks             = fd_get_blocks,
 536 };
 537
 538 static int __init fileio_module_init(void)
 539 {
 540         return transport_subsystem_register(&fileio_template);
 541 }
 542
 543 static void fileio_module_exit(void)
 544 {
 545         transport_subsystem_release(&fileio_template);
 546 }
 547
 548 MODULE_DESCRIPTION("TCM FILEIO subsystem plugin");
 549 MODULE_AUTHOR("nab@Linux-iSCSI.org");
 550 MODULE_LICENSE("GPL");
 551
 552 module_init(fileio_module_init);
 553 module_exit(fileio_module_exit);