root/fs/nfs/blocklayout/blocklayout.c

DEFINITIONS

1. is_hole
2. alloc_parallel
3. get_parallel
4. destroy_parallel
5. put_parallel
6. bl_submit_bio
7. bl_alloc_init_bio
8. offset_in_map
9. do_add_page_to_bio
10. bl_mark_devices_unavailable
11. bl_end_io_read
12. bl_read_cleanup
13. bl_end_par_io_read
14. bl_read_pagelist
15. bl_end_io_write
16. bl_write_cleanup
17. bl_end_par_io_write
18. bl_write_pagelist
19. bl_free_layout_hdr
20. __bl_alloc_layout_hdr
21. bl_alloc_layout_hdr
22. sl_alloc_layout_hdr
23. bl_free_lseg
24. verify_extent
25. decode_sector_number
26. bl_find_get_deviceid
27. bl_alloc_extent
28. bl_alloc_lseg
29. bl_return_range
30. bl_prepare_layoutcommit
31. bl_cleanup_layoutcommit
32. bl_set_layoutdriver
33. is_aligned_req
34. bl_pg_init_read
35. bl_pg_test_read
36. pnfs_num_cont_bytes
37. bl_pg_init_write
38. bl_pg_test_write
39. nfs4blocklayout_init
40. nfs4blocklayout_exit

   1 /*
   2  *  linux/fs/nfs/blocklayout/blocklayout.c
   3  *
   4  *  Module for the NFSv4.1 pNFS block layout driver.
   5  *
   6  *  Copyright (c) 2006 The Regents of the University of Michigan.
   7  *  All rights reserved.
   8  *
   9  *  Andy Adamson <andros@citi.umich.edu>
  10  *  Fred Isaman <iisaman@umich.edu>
  11  *
  12  * permission is granted to use, copy, create derivative works and
  13  * redistribute this software and such derivative works for any purpose,
  14  * so long as the name of the university of michigan is not used in
  15  * any advertising or publicity pertaining to the use or distribution
  16  * of this software without specific, written prior authorization.  if
  17  * the above copyright notice or any other identification of the
  18  * university of michigan is included in any copy of any portion of
  19  * this software, then the disclaimer below must also be included.
  20  *
  21  * this software is provided as is, without representation from the
  22  * university of michigan as to its fitness for any purpose, and without
  23  * warranty by the university of michigan of any kind, either express
  24  * or implied, including without limitation the implied warranties of
  25  * merchantability and fitness for a particular purpose.  the regents
  26  * of the university of michigan shall not be liable for any damages,
  27  * including special, indirect, incidental, or consequential damages,
  28  * with respect to any claim arising out or in connection with the use
  29  * of the software, even if it has been or is hereafter advised of the
  30  * possibility of such damages.
  31  */
  32 
  33 #include <linux/module.h>
  34 #include <linux/init.h>
  35 #include <linux/mount.h>
  36 #include <linux/namei.h>
  37 #include <linux/bio.h>          /* struct bio */
  38 #include <linux/prefetch.h>
  39 #include <linux/pagevec.h>
  40 
  41 #include "../pnfs.h"
  42 #include "../nfs4session.h"
  43 #include "../internal.h"
  44 #include "blocklayout.h"
  45 
  46 #define NFSDBG_FACILITY NFSDBG_PNFS_LD
  47 
  48 MODULE_LICENSE("GPL");
  49 MODULE_AUTHOR("Andy Adamson <andros@citi.umich.edu>");
  50 MODULE_DESCRIPTION("The NFSv4.1 pNFS Block layout driver");
  51 
  52 static bool is_hole(struct pnfs_block_extent *be)
  53 {
  54         switch (be->be_state) {
  55         case PNFS_BLOCK_NONE_DATA:
  56                 return true;
  57         case PNFS_BLOCK_INVALID_DATA:
  58                 return be->be_tag ? false : true;
  59         default:
  60                 return false;
  61         }
  62 }
  63 
  64 /* The data we are handed might be spread across several bios.  We need
  65  * to track when the last one is finished.
  66  */
  67 struct parallel_io {
  68         struct kref refcnt;
  69         void (*pnfs_callback) (void *data);
  70         void *data;
  71 };
  72 
  73 static inline struct parallel_io *alloc_parallel(void *data)
  74 {
  75         struct parallel_io *rv;
  76 
  77         rv  = kmalloc(sizeof(*rv), GFP_NOFS);
  78         if (rv) {
  79                 rv->data = data;
  80                 kref_init(&rv->refcnt);
  81         }
  82         return rv;
  83 }
  84 
  85 static inline void get_parallel(struct parallel_io *p)
  86 {
  87         kref_get(&p->refcnt);
  88 }
  89 
  90 static void destroy_parallel(struct kref *kref)
  91 {
  92         struct parallel_io *p = container_of(kref, struct parallel_io, refcnt);
  93 
  94         dprintk("%s enter\n", __func__);
  95         p->pnfs_callback(p->data);
  96         kfree(p);
  97 }
  98 
  99 static inline void put_parallel(struct parallel_io *p)
 100 {
 101         kref_put(&p->refcnt, destroy_parallel);
 102 }
 103 
 104 static struct bio *
 105 bl_submit_bio(struct bio *bio)
 106 {
 107         if (bio) {
 108                 get_parallel(bio->bi_private);
 109                 dprintk("%s submitting %s bio %u@%llu\n", __func__,
 110                         bio_op(bio) == READ ? "read" : "write",
 111                         bio->bi_iter.bi_size,
 112                         (unsigned long long)bio->bi_iter.bi_sector);
 113                 submit_bio(bio);
 114         }
 115         return NULL;
 116 }
 117 
 118 static struct bio *
 119 bl_alloc_init_bio(int npg, struct block_device *bdev, sector_t disk_sector,
 120                 bio_end_io_t end_io, struct parallel_io *par)
 121 {
 122         struct bio *bio;
 123 
 124         npg = min(npg, BIO_MAX_PAGES);
 125         bio = bio_alloc(GFP_NOIO, npg);
 126         if (!bio && (current->flags & PF_MEMALLOC)) {
 127                 while (!bio && (npg /= 2))
 128                         bio = bio_alloc(GFP_NOIO, npg);
 129         }
 130 
 131         if (bio) {
 132                 bio->bi_iter.bi_sector = disk_sector;
 133                 bio_set_dev(bio, bdev);
 134                 bio->bi_end_io = end_io;
 135                 bio->bi_private = par;
 136         }
 137         return bio;
 138 }
 139 
 140 static bool offset_in_map(u64 offset, struct pnfs_block_dev_map *map)
 141 {
 142         return offset >= map->start && offset < map->start + map->len;
 143 }
 144 
 145 static struct bio *
 146 do_add_page_to_bio(struct bio *bio, int npg, int rw, sector_t isect,
 147                 struct page *page, struct pnfs_block_dev_map *map,
 148                 struct pnfs_block_extent *be, bio_end_io_t end_io,
 149                 struct parallel_io *par, unsigned int offset, int *len)
 150 {
 151         struct pnfs_block_dev *dev =
 152                 container_of(be->be_device, struct pnfs_block_dev, node);
 153         u64 disk_addr, end;
 154 
 155         dprintk("%s: npg %d rw %d isect %llu offset %u len %d\n", __func__,
 156                 npg, rw, (unsigned long long)isect, offset, *len);
 157 
 158         /* translate to device offset */
 159         isect += be->be_v_offset;
 160         isect -= be->be_f_offset;
 161 
 162         /* translate to physical disk offset */
 163         disk_addr = (u64)isect << SECTOR_SHIFT;
 164         if (!offset_in_map(disk_addr, map)) {
 165                 if (!dev->map(dev, disk_addr, map) || !offset_in_map(disk_addr, map))
 166                         return ERR_PTR(-EIO);
 167                 bio = bl_submit_bio(bio);
 168         }
 169         disk_addr += map->disk_offset;
 170         disk_addr -= map->start;
 171 
 172         /* limit length to what the device mapping allows */
 173         end = disk_addr + *len;
 174         if (end >= map->start + map->len)
 175                 *len = map->start + map->len - disk_addr;
 176 
 177 retry:
 178         if (!bio) {
 179                 bio = bl_alloc_init_bio(npg, map->bdev,
 180                                 disk_addr >> SECTOR_SHIFT, end_io, par);
 181                 if (!bio)
 182                         return ERR_PTR(-ENOMEM);
 183                 bio_set_op_attrs(bio, rw, 0);
 184         }
 185         if (bio_add_page(bio, page, *len, offset) < *len) {
 186                 bio = bl_submit_bio(bio);
 187                 goto retry;
 188         }
 189         return bio;
 190 }
 191 
 192 static void bl_mark_devices_unavailable(struct nfs_pgio_header *header, bool rw)
 193 {
 194         struct pnfs_block_layout *bl = BLK_LSEG2EXT(header->lseg);
 195         size_t bytes_left = header->args.count;
 196         sector_t isect, extent_length = 0;
 197         struct pnfs_block_extent be;
 198 
 199         isect = header->args.offset >> SECTOR_SHIFT;
 200         bytes_left += header->args.offset - (isect << SECTOR_SHIFT);
 201 
 202         while (bytes_left > 0) {
 203                 if (!ext_tree_lookup(bl, isect, &be, rw))
 204                                 return;
 205                 extent_length = be.be_length - (isect - be.be_f_offset);
 206                 nfs4_mark_deviceid_unavailable(be.be_device);
 207                 isect += extent_length;
 208                 if (bytes_left > extent_length << SECTOR_SHIFT)
 209                         bytes_left -= extent_length << SECTOR_SHIFT;
 210                 else
 211                         bytes_left = 0;
 212         }
 213 }
 214 
 215 static void bl_end_io_read(struct bio *bio)
 216 {
 217         struct parallel_io *par = bio->bi_private;
 218 
 219         if (bio->bi_status) {
 220                 struct nfs_pgio_header *header = par->data;
 221 
 222                 if (!header->pnfs_error)
 223                         header->pnfs_error = -EIO;
 224                 pnfs_set_lo_fail(header->lseg);
 225                 bl_mark_devices_unavailable(header, false);
 226         }
 227 
 228         bio_put(bio);
 229         put_parallel(par);
 230 }
 231 
 232 static void bl_read_cleanup(struct work_struct *work)
 233 {
 234         struct rpc_task *task;
 235         struct nfs_pgio_header *hdr;
 236         dprintk("%s enter\n", __func__);
 237         task = container_of(work, struct rpc_task, u.tk_work);
 238         hdr = container_of(task, struct nfs_pgio_header, task);
 239         pnfs_ld_read_done(hdr);
 240 }
 241 
 242 static void
 243 bl_end_par_io_read(void *data)
 244 {
 245         struct nfs_pgio_header *hdr = data;
 246 
 247         hdr->task.tk_status = hdr->pnfs_error;
 248         INIT_WORK(&hdr->task.u.tk_work, bl_read_cleanup);
 249         schedule_work(&hdr->task.u.tk_work);
 250 }
 251 
 252 static enum pnfs_try_status
 253 bl_read_pagelist(struct nfs_pgio_header *header)
 254 {
 255         struct pnfs_block_layout *bl = BLK_LSEG2EXT(header->lseg);
 256         struct pnfs_block_dev_map map = { .start = NFS4_MAX_UINT64 };
 257         struct bio *bio = NULL;
 258         struct pnfs_block_extent be;
 259         sector_t isect, extent_length = 0;
 260         struct parallel_io *par;
 261         loff_t f_offset = header->args.offset;
 262         size_t bytes_left = header->args.count;
 263         unsigned int pg_offset = header->args.pgbase, pg_len;
 264         struct page **pages = header->args.pages;
 265         int pg_index = header->args.pgbase >> PAGE_SHIFT;
 266         const bool is_dio = (header->dreq != NULL);
 267         struct blk_plug plug;
 268         int i;
 269 
 270         dprintk("%s enter nr_pages %u offset %lld count %u\n", __func__,
 271                 header->page_array.npages, f_offset,
 272                 (unsigned int)header->args.count);
 273 
 274         par = alloc_parallel(header);
 275         if (!par)
 276                 return PNFS_NOT_ATTEMPTED;
 277         par->pnfs_callback = bl_end_par_io_read;
 278 
 279         blk_start_plug(&plug);
 280 
 281         isect = (sector_t) (f_offset >> SECTOR_SHIFT);
 282         /* Code assumes extents are page-aligned */
 283         for (i = pg_index; i < header->page_array.npages; i++) {
 284                 if (extent_length <= 0) {
 285                         /* We've used up the previous extent */
 286                         bio = bl_submit_bio(bio);
 287 
 288                         /* Get the next one */
 289                         if (!ext_tree_lookup(bl, isect, &be, false)) {
 290                                 header->pnfs_error = -EIO;
 291                                 goto out;
 292                         }
 293                         extent_length = be.be_length - (isect - be.be_f_offset);
 294                 }
 295 
 296                 if (is_dio) {
 297                         if (pg_offset + bytes_left > PAGE_SIZE)
 298                                 pg_len = PAGE_SIZE - pg_offset;
 299                         else
 300                                 pg_len = bytes_left;
 301                 } else {
 302                         BUG_ON(pg_offset != 0);
 303                         pg_len = PAGE_SIZE;
 304                 }
 305 
 306                 if (is_hole(&be)) {
 307                         bio = bl_submit_bio(bio);
 308                         /* Fill hole w/ zeroes w/o accessing device */
 309                         dprintk("%s Zeroing page for hole\n", __func__);
 310                         zero_user_segment(pages[i], pg_offset, pg_len);
 311 
 312                         /* invalidate map */
 313                         map.start = NFS4_MAX_UINT64;
 314                 } else {
 315                         bio = do_add_page_to_bio(bio,
 316                                                  header->page_array.npages - i,
 317                                                  READ,
 318                                                  isect, pages[i], &map, &be,
 319                                                  bl_end_io_read, par,
 320                                                  pg_offset, &pg_len);
 321                         if (IS_ERR(bio)) {
 322                                 header->pnfs_error = PTR_ERR(bio);
 323                                 bio = NULL;
 324                                 goto out;
 325                         }
 326                 }
 327                 isect += (pg_len >> SECTOR_SHIFT);
 328                 extent_length -= (pg_len >> SECTOR_SHIFT);
 329                 f_offset += pg_len;
 330                 bytes_left -= pg_len;
 331                 pg_offset = 0;
 332         }
 333         if ((isect << SECTOR_SHIFT) >= header->inode->i_size) {
 334                 header->res.eof = 1;
 335                 header->res.count = header->inode->i_size - header->args.offset;
 336         } else {
 337                 header->res.count = (isect << SECTOR_SHIFT) - header->args.offset;
 338         }
 339 out:
 340         bl_submit_bio(bio);
 341         blk_finish_plug(&plug);
 342         put_parallel(par);
 343         return PNFS_ATTEMPTED;
 344 }
 345 
 346 static void bl_end_io_write(struct bio *bio)
 347 {
 348         struct parallel_io *par = bio->bi_private;
 349         struct nfs_pgio_header *header = par->data;
 350 
 351         if (bio->bi_status) {
 352                 if (!header->pnfs_error)
 353                         header->pnfs_error = -EIO;
 354                 pnfs_set_lo_fail(header->lseg);
 355                 bl_mark_devices_unavailable(header, true);
 356         }
 357         bio_put(bio);
 358         put_parallel(par);
 359 }
 360 
 361 /* Function scheduled for call during bl_end_par_io_write,
 362  * it marks sectors as written and extends the commitlist.
 363  */
 364 static void bl_write_cleanup(struct work_struct *work)
 365 {
 366         struct rpc_task *task = container_of(work, struct rpc_task, u.tk_work);
 367         struct nfs_pgio_header *hdr =
 368                         container_of(task, struct nfs_pgio_header, task);
 369 
 370         dprintk("%s enter\n", __func__);
 371 
 372         if (likely(!hdr->pnfs_error)) {
 373                 struct pnfs_block_layout *bl = BLK_LSEG2EXT(hdr->lseg);
 374                 u64 start = hdr->args.offset & (loff_t)PAGE_MASK;
 375                 u64 end = (hdr->args.offset + hdr->args.count +
 376                         PAGE_SIZE - 1) & (loff_t)PAGE_MASK;
 377                 u64 lwb = hdr->args.offset + hdr->args.count;
 378 
 379                 ext_tree_mark_written(bl, start >> SECTOR_SHIFT,
 380                                         (end - start) >> SECTOR_SHIFT, lwb);
 381         }
 382 
 383         pnfs_ld_write_done(hdr);
 384 }
 385 
 386 /* Called when last of bios associated with a bl_write_pagelist call finishes */
 387 static void bl_end_par_io_write(void *data)
 388 {
 389         struct nfs_pgio_header *hdr = data;
 390 
 391         hdr->task.tk_status = hdr->pnfs_error;
 392         hdr->verf.committed = NFS_FILE_SYNC;
 393         INIT_WORK(&hdr->task.u.tk_work, bl_write_cleanup);
 394         schedule_work(&hdr->task.u.tk_work);
 395 }
 396 
 397 static enum pnfs_try_status
 398 bl_write_pagelist(struct nfs_pgio_header *header, int sync)
 399 {
 400         struct pnfs_block_layout *bl = BLK_LSEG2EXT(header->lseg);
 401         struct pnfs_block_dev_map map = { .start = NFS4_MAX_UINT64 };
 402         struct bio *bio = NULL;
 403         struct pnfs_block_extent be;
 404         sector_t isect, extent_length = 0;
 405         struct parallel_io *par = NULL;
 406         loff_t offset = header->args.offset;
 407         size_t count = header->args.count;
 408         struct page **pages = header->args.pages;
 409         int pg_index = header->args.pgbase >> PAGE_SHIFT;
 410         unsigned int pg_len;
 411         struct blk_plug plug;
 412         int i;
 413 
 414         dprintk("%s enter, %zu@%lld\n", __func__, count, offset);
 415 
 416         /* At this point, header->page_aray is a (sequential) list of nfs_pages.
 417          * We want to write each, and if there is an error set pnfs_error
 418          * to have it redone using nfs.
 419          */
 420         par = alloc_parallel(header);
 421         if (!par)
 422                 return PNFS_NOT_ATTEMPTED;
 423         par->pnfs_callback = bl_end_par_io_write;
 424 
 425         blk_start_plug(&plug);
 426 
 427         /* we always write out the whole page */
 428         offset = offset & (loff_t)PAGE_MASK;
 429         isect = offset >> SECTOR_SHIFT;
 430 
 431         for (i = pg_index; i < header->page_array.npages; i++) {
 432                 if (extent_length <= 0) {
 433                         /* We've used up the previous extent */
 434                         bio = bl_submit_bio(bio);
 435                         /* Get the next one */
 436                         if (!ext_tree_lookup(bl, isect, &be, true)) {
 437                                 header->pnfs_error = -EINVAL;
 438                                 goto out;
 439                         }
 440 
 441                         extent_length = be.be_length - (isect - be.be_f_offset);
 442                 }
 443 
 444                 pg_len = PAGE_SIZE;
 445                 bio = do_add_page_to_bio(bio, header->page_array.npages - i,
 446                                          WRITE, isect, pages[i], &map, &be,
 447                                          bl_end_io_write, par,
 448                                          0, &pg_len);
 449                 if (IS_ERR(bio)) {
 450                         header->pnfs_error = PTR_ERR(bio);
 451                         bio = NULL;
 452                         goto out;
 453                 }
 454 
 455                 offset += pg_len;
 456                 count -= pg_len;
 457                 isect += (pg_len >> SECTOR_SHIFT);
 458                 extent_length -= (pg_len >> SECTOR_SHIFT);
 459         }
 460 
 461         header->res.count = header->args.count;
 462 out:
 463         bl_submit_bio(bio);
 464         blk_finish_plug(&plug);
 465         put_parallel(par);
 466         return PNFS_ATTEMPTED;
 467 }
 468 
 469 static void bl_free_layout_hdr(struct pnfs_layout_hdr *lo)
 470 {
 471         struct pnfs_block_layout *bl = BLK_LO2EXT(lo);
 472         int err;
 473 
 474         dprintk("%s enter\n", __func__);
 475 
 476         err = ext_tree_remove(bl, true, 0, LLONG_MAX);
 477         WARN_ON(err);
 478 
 479         kfree(bl);
 480 }
 481 
 482 static struct pnfs_layout_hdr *__bl_alloc_layout_hdr(struct inode *inode,
 483                 gfp_t gfp_flags, bool is_scsi_layout)
 484 {
 485         struct pnfs_block_layout *bl;
 486 
 487         dprintk("%s enter\n", __func__);
 488         bl = kzalloc(sizeof(*bl), gfp_flags);
 489         if (!bl)
 490                 return NULL;
 491 
 492         bl->bl_ext_rw = RB_ROOT;
 493         bl->bl_ext_ro = RB_ROOT;
 494         spin_lock_init(&bl->bl_ext_lock);
 495 
 496         bl->bl_scsi_layout = is_scsi_layout;
 497         return &bl->bl_layout;
 498 }
 499 
 500 static struct pnfs_layout_hdr *bl_alloc_layout_hdr(struct inode *inode,
 501                                                    gfp_t gfp_flags)
 502 {
 503         return __bl_alloc_layout_hdr(inode, gfp_flags, false);
 504 }
 505 
 506 static struct pnfs_layout_hdr *sl_alloc_layout_hdr(struct inode *inode,
 507                                                    gfp_t gfp_flags)
 508 {
 509         return __bl_alloc_layout_hdr(inode, gfp_flags, true);
 510 }
 511 
 512 static void bl_free_lseg(struct pnfs_layout_segment *lseg)
 513 {
 514         dprintk("%s enter\n", __func__);
 515         kfree(lseg);
 516 }
 517 
 518 /* Tracks info needed to ensure extents in layout obey constraints of spec */
 519 struct layout_verification {
 520         u32 mode;       /* R or RW */
 521         u64 start;      /* Expected start of next non-COW extent */
 522         u64 inval;      /* Start of INVAL coverage */
 523         u64 cowread;    /* End of COW read coverage */
 524 };
 525 
 526 /* Verify the extent meets the layout requirements of the pnfs-block draft,
 527  * section 2.3.1.
 528  */
 529 static int verify_extent(struct pnfs_block_extent *be,
 530                          struct layout_verification *lv)
 531 {
 532         if (lv->mode == IOMODE_READ) {
 533                 if (be->be_state == PNFS_BLOCK_READWRITE_DATA ||
 534                     be->be_state == PNFS_BLOCK_INVALID_DATA)
 535                         return -EIO;
 536                 if (be->be_f_offset != lv->start)
 537                         return -EIO;
 538                 lv->start += be->be_length;
 539                 return 0;
 540         }
 541         /* lv->mode == IOMODE_RW */
 542         if (be->be_state == PNFS_BLOCK_READWRITE_DATA) {
 543                 if (be->be_f_offset != lv->start)
 544                         return -EIO;
 545                 if (lv->cowread > lv->start)
 546                         return -EIO;
 547                 lv->start += be->be_length;
 548                 lv->inval = lv->start;
 549                 return 0;
 550         } else if (be->be_state == PNFS_BLOCK_INVALID_DATA) {
 551                 if (be->be_f_offset != lv->start)
 552                         return -EIO;
 553                 lv->start += be->be_length;
 554                 return 0;
 555         } else if (be->be_state == PNFS_BLOCK_READ_DATA) {
 556                 if (be->be_f_offset > lv->start)
 557                         return -EIO;
 558                 if (be->be_f_offset < lv->inval)
 559                         return -EIO;
 560                 if (be->be_f_offset < lv->cowread)
 561                         return -EIO;
 562                 /* It looks like you might want to min this with lv->start,
 563                  * but you really don't.
 564                  */
 565                 lv->inval = lv->inval + be->be_length;
 566                 lv->cowread = be->be_f_offset + be->be_length;
 567                 return 0;
 568         } else
 569                 return -EIO;
 570 }
 571 
 572 static int decode_sector_number(__be32 **rp, sector_t *sp)
 573 {
 574         uint64_t s;
 575 
 576         *rp = xdr_decode_hyper(*rp, &s);
 577         if (s & 0x1ff) {
 578                 printk(KERN_WARNING "NFS: %s: sector not aligned\n", __func__);
 579                 return -1;
 580         }
 581         *sp = s >> SECTOR_SHIFT;
 582         return 0;
 583 }
 584 
 585 static struct nfs4_deviceid_node *
 586 bl_find_get_deviceid(struct nfs_server *server,
 587                 const struct nfs4_deviceid *id, const struct cred *cred,
 588                 gfp_t gfp_mask)
 589 {
 590         struct nfs4_deviceid_node *node;
 591         unsigned long start, end;
 592 
 593 retry:
 594         node = nfs4_find_get_deviceid(server, id, cred, gfp_mask);
 595         if (!node)
 596                 return ERR_PTR(-ENODEV);
 597 
 598         if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags) == 0)
 599                 return node;
 600 
 601         end = jiffies;
 602         start = end - PNFS_DEVICE_RETRY_TIMEOUT;
 603         if (!time_in_range(node->timestamp_unavailable, start, end)) {
 604                 nfs4_delete_deviceid(node->ld, node->nfs_client, id);
 605                 goto retry;
 606         }
 607         return ERR_PTR(-ENODEV);
 608 }
 609 
 610 static int
 611 bl_alloc_extent(struct xdr_stream *xdr, struct pnfs_layout_hdr *lo,
 612                 struct layout_verification *lv, struct list_head *extents,
 613                 gfp_t gfp_mask)
 614 {
 615         struct pnfs_block_extent *be;
 616         struct nfs4_deviceid id;
 617         int error;
 618         __be32 *p;
 619 
 620         p = xdr_inline_decode(xdr, 28 + NFS4_DEVICEID4_SIZE);
 621         if (!p)
 622                 return -EIO;
 623 
 624         be = kzalloc(sizeof(*be), GFP_NOFS);
 625         if (!be)
 626                 return -ENOMEM;
 627 
 628         memcpy(&id, p, NFS4_DEVICEID4_SIZE);
 629         p += XDR_QUADLEN(NFS4_DEVICEID4_SIZE);
 630 
 631         be->be_device = bl_find_get_deviceid(NFS_SERVER(lo->plh_inode), &id,
 632                                                 lo->plh_lc_cred, gfp_mask);
 633         if (IS_ERR(be->be_device)) {
 634                 error = PTR_ERR(be->be_device);
 635                 goto out_free_be;
 636         }
 637 
 638         /*
 639          * The next three values are read in as bytes, but stored in the
 640          * extent structure in 512-byte granularity.
 641          */
 642         error = -EIO;
 643         if (decode_sector_number(&p, &be->be_f_offset) < 0)
 644                 goto out_put_deviceid;
 645         if (decode_sector_number(&p, &be->be_length) < 0)
 646                 goto out_put_deviceid;
 647         if (decode_sector_number(&p, &be->be_v_offset) < 0)
 648                 goto out_put_deviceid;
 649         be->be_state = be32_to_cpup(p++);
 650 
 651         error = verify_extent(be, lv);
 652         if (error) {
 653                 dprintk("%s: extent verification failed\n", __func__);
 654                 goto out_put_deviceid;
 655         }
 656 
 657         list_add_tail(&be->be_list, extents);
 658         return 0;
 659 
 660 out_put_deviceid:
 661         nfs4_put_deviceid_node(be->be_device);
 662 out_free_be:
 663         kfree(be);
 664         return error;
 665 }
 666 
 667 static struct pnfs_layout_segment *
 668 bl_alloc_lseg(struct pnfs_layout_hdr *lo, struct nfs4_layoutget_res *lgr,
 669                 gfp_t gfp_mask)
 670 {
 671         struct layout_verification lv = {
 672                 .mode = lgr->range.iomode,
 673                 .start = lgr->range.offset >> SECTOR_SHIFT,
 674                 .inval = lgr->range.offset >> SECTOR_SHIFT,
 675                 .cowread = lgr->range.offset >> SECTOR_SHIFT,
 676         };
 677         struct pnfs_block_layout *bl = BLK_LO2EXT(lo);
 678         struct pnfs_layout_segment *lseg;
 679         struct xdr_buf buf;
 680         struct xdr_stream xdr;
 681         struct page *scratch;
 682         int status, i;
 683         uint32_t count;
 684         __be32 *p;
 685         LIST_HEAD(extents);
 686 
 687         dprintk("---> %s\n", __func__);
 688 
 689         lseg = kzalloc(sizeof(*lseg), gfp_mask);
 690         if (!lseg)
 691                 return ERR_PTR(-ENOMEM);
 692 
 693         status = -ENOMEM;
 694         scratch = alloc_page(gfp_mask);
 695         if (!scratch)
 696                 goto out;
 697 
 698         xdr_init_decode_pages(&xdr, &buf,
 699                         lgr->layoutp->pages, lgr->layoutp->len);
 700         xdr_set_scratch_buffer(&xdr, page_address(scratch), PAGE_SIZE);
 701 
 702         status = -EIO;
 703         p = xdr_inline_decode(&xdr, 4);
 704         if (unlikely(!p))
 705                 goto out_free_scratch;
 706 
 707         count = be32_to_cpup(p++);
 708         dprintk("%s: number of extents %d\n", __func__, count);
 709 
 710         /*
 711          * Decode individual extents, putting them in temporary staging area
 712          * until whole layout is decoded to make error recovery easier.
 713          */
 714         for (i = 0; i < count; i++) {
 715                 status = bl_alloc_extent(&xdr, lo, &lv, &extents, gfp_mask);
 716                 if (status)
 717                         goto process_extents;
 718         }
 719 
 720         if (lgr->range.offset + lgr->range.length !=
 721                         lv.start << SECTOR_SHIFT) {
 722                 dprintk("%s Final length mismatch\n", __func__);
 723                 status = -EIO;
 724                 goto process_extents;
 725         }
 726 
 727         if (lv.start < lv.cowread) {
 728                 dprintk("%s Final uncovered COW extent\n", __func__);
 729                 status = -EIO;
 730         }
 731 
 732 process_extents:
 733         while (!list_empty(&extents)) {
 734                 struct pnfs_block_extent *be =
 735                         list_first_entry(&extents, struct pnfs_block_extent,
 736                                          be_list);
 737                 list_del(&be->be_list);
 738 
 739                 if (!status)
 740                         status = ext_tree_insert(bl, be);
 741 
 742                 if (status) {
 743                         nfs4_put_deviceid_node(be->be_device);
 744                         kfree(be);
 745                 }
 746         }
 747 
 748 out_free_scratch:
 749         __free_page(scratch);
 750 out:
 751         dprintk("%s returns %d\n", __func__, status);
 752         switch (status) {
 753         case -ENODEV:
 754                 /* Our extent block devices are unavailable */
 755                 set_bit(NFS_LSEG_UNAVAILABLE, &lseg->pls_flags);
 756                 /* Fall through */
 757         case 0:
 758                 return lseg;
 759         default:
 760                 kfree(lseg);
 761                 return ERR_PTR(status);
 762         }
 763 }
 764 
 765 static void
 766 bl_return_range(struct pnfs_layout_hdr *lo,
 767                 struct pnfs_layout_range *range)
 768 {
 769         struct pnfs_block_layout *bl = BLK_LO2EXT(lo);
 770         sector_t offset = range->offset >> SECTOR_SHIFT, end;
 771 
 772         if (range->offset % 8) {
 773                 dprintk("%s: offset %lld not block size aligned\n",
 774                         __func__, range->offset);
 775                 return;
 776         }
 777 
 778         if (range->length != NFS4_MAX_UINT64) {
 779                 if (range->length % 8) {
 780                         dprintk("%s: length %lld not block size aligned\n",
 781                                 __func__, range->length);
 782                         return;
 783                 }
 784 
 785                 end = offset + (range->length >> SECTOR_SHIFT);
 786         } else {
 787                 end = round_down(NFS4_MAX_UINT64, PAGE_SIZE);
 788         }
 789 
 790         ext_tree_remove(bl, range->iomode & IOMODE_RW, offset, end);
 791 }
 792 
 793 static int
 794 bl_prepare_layoutcommit(struct nfs4_layoutcommit_args *arg)
 795 {
 796         return ext_tree_prepare_commit(arg);
 797 }
 798 
 799 static void
 800 bl_cleanup_layoutcommit(struct nfs4_layoutcommit_data *lcdata)
 801 {
 802         ext_tree_mark_committed(&lcdata->args, lcdata->res.status);
 803 }
 804 
 805 static int
 806 bl_set_layoutdriver(struct nfs_server *server, const struct nfs_fh *fh)
 807 {
 808         dprintk("%s enter\n", __func__);
 809 
 810         if (server->pnfs_blksize == 0) {
 811                 dprintk("%s Server did not return blksize\n", __func__);
 812                 return -EINVAL;
 813         }
 814         if (server->pnfs_blksize > PAGE_SIZE) {
 815                 printk(KERN_ERR "%s: pNFS blksize %d not supported.\n",
 816                         __func__, server->pnfs_blksize);
 817                 return -EINVAL;
 818         }
 819 
 820         return 0;
 821 }
 822 
 823 static bool
 824 is_aligned_req(struct nfs_pageio_descriptor *pgio,
 825                 struct nfs_page *req, unsigned int alignment, bool is_write)
 826 {
 827         /*
 828          * Always accept buffered writes, higher layers take care of the
 829          * right alignment.
 830          */
 831         if (pgio->pg_dreq == NULL)
 832                 return true;
 833 
 834         if (!IS_ALIGNED(req->wb_offset, alignment))
 835                 return false;
 836 
 837         if (IS_ALIGNED(req->wb_bytes, alignment))
 838                 return true;
 839 
 840         if (is_write &&
 841             (req_offset(req) + req->wb_bytes == i_size_read(pgio->pg_inode))) {
 842                 /*
 843                  * If the write goes up to the inode size, just write
 844                  * the full page.  Data past the inode size is
 845                  * guaranteed to be zeroed by the higher level client
 846                  * code, and this behaviour is mandated by RFC 5663
 847                  * section 2.3.2.
 848                  */
 849                 return true;
 850         }
 851 
 852         return false;
 853 }
 854 
 855 static void
 856 bl_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
 857 {
 858         if (!is_aligned_req(pgio, req, SECTOR_SIZE, false)) {
 859                 nfs_pageio_reset_read_mds(pgio);
 860                 return;
 861         }
 862 
 863         pnfs_generic_pg_init_read(pgio, req);
 864 
 865         if (pgio->pg_lseg &&
 866                 test_bit(NFS_LSEG_UNAVAILABLE, &pgio->pg_lseg->pls_flags)) {
 867                 pnfs_error_mark_layout_for_return(pgio->pg_inode, pgio->pg_lseg);
 868                 pnfs_set_lo_fail(pgio->pg_lseg);
 869                 nfs_pageio_reset_read_mds(pgio);
 870         }
 871 }
 872 
 873 /*
 874  * Return 0 if @req cannot be coalesced into @pgio, otherwise return the number
 875  * of bytes (maximum @req->wb_bytes) that can be coalesced.
 876  */
 877 static size_t
 878 bl_pg_test_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
 879                 struct nfs_page *req)
 880 {
 881         if (!is_aligned_req(pgio, req, SECTOR_SIZE, false))
 882                 return 0;
 883         return pnfs_generic_pg_test(pgio, prev, req);
 884 }
 885 
 886 /*
 887  * Return the number of contiguous bytes for a given inode
 888  * starting at page frame idx.
 889  */
 890 static u64 pnfs_num_cont_bytes(struct inode *inode, pgoff_t idx)
 891 {
 892         struct address_space *mapping = inode->i_mapping;
 893         pgoff_t end;
 894 
 895         /* Optimize common case that writes from 0 to end of file */
 896         end = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
 897         if (end != inode->i_mapping->nrpages) {
 898                 rcu_read_lock();
 899                 end = page_cache_next_miss(mapping, idx + 1, ULONG_MAX);
 900                 rcu_read_unlock();
 901         }
 902 
 903         if (!end)
 904                 return i_size_read(inode) - (idx << PAGE_SHIFT);
 905         else
 906                 return (end - idx) << PAGE_SHIFT;
 907 }
 908 
 909 static void
 910 bl_pg_init_write(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
 911 {
 912         u64 wb_size;
 913 
 914         if (!is_aligned_req(pgio, req, PAGE_SIZE, true)) {
 915                 nfs_pageio_reset_write_mds(pgio);
 916                 return;
 917         }
 918 
 919         if (pgio->pg_dreq == NULL)
 920                 wb_size = pnfs_num_cont_bytes(pgio->pg_inode,
 921                                               req->wb_index);
 922         else
 923                 wb_size = nfs_dreq_bytes_left(pgio->pg_dreq);
 924 
 925         pnfs_generic_pg_init_write(pgio, req, wb_size);
 926 
 927         if (pgio->pg_lseg &&
 928                 test_bit(NFS_LSEG_UNAVAILABLE, &pgio->pg_lseg->pls_flags)) {
 929 
 930                 pnfs_error_mark_layout_for_return(pgio->pg_inode, pgio->pg_lseg);
 931                 pnfs_set_lo_fail(pgio->pg_lseg);
 932                 nfs_pageio_reset_write_mds(pgio);
 933         }
 934 }
 935 
 936 /*
 937  * Return 0 if @req cannot be coalesced into @pgio, otherwise return the number
 938  * of bytes (maximum @req->wb_bytes) that can be coalesced.
 939  */
 940 static size_t
 941 bl_pg_test_write(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
 942                  struct nfs_page *req)
 943 {
 944         if (!is_aligned_req(pgio, req, PAGE_SIZE, true))
 945                 return 0;
 946         return pnfs_generic_pg_test(pgio, prev, req);
 947 }
 948 
 949 static const struct nfs_pageio_ops bl_pg_read_ops = {
 950         .pg_init = bl_pg_init_read,
 951         .pg_test = bl_pg_test_read,
 952         .pg_doio = pnfs_generic_pg_readpages,
 953         .pg_cleanup = pnfs_generic_pg_cleanup,
 954 };
 955 
 956 static const struct nfs_pageio_ops bl_pg_write_ops = {
 957         .pg_init = bl_pg_init_write,
 958         .pg_test = bl_pg_test_write,
 959         .pg_doio = pnfs_generic_pg_writepages,
 960         .pg_cleanup = pnfs_generic_pg_cleanup,
 961 };
 962 
 963 static struct pnfs_layoutdriver_type blocklayout_type = {
 964         .id                             = LAYOUT_BLOCK_VOLUME,
 965         .name                           = "LAYOUT_BLOCK_VOLUME",
 966         .owner                          = THIS_MODULE,
 967         .flags                          = PNFS_LAYOUTRET_ON_SETATTR |
 968                                           PNFS_LAYOUTRET_ON_ERROR |
 969                                           PNFS_READ_WHOLE_PAGE,
 970         .read_pagelist                  = bl_read_pagelist,
 971         .write_pagelist                 = bl_write_pagelist,
 972         .alloc_layout_hdr               = bl_alloc_layout_hdr,
 973         .free_layout_hdr                = bl_free_layout_hdr,
 974         .alloc_lseg                     = bl_alloc_lseg,
 975         .free_lseg                      = bl_free_lseg,
 976         .return_range                   = bl_return_range,
 977         .prepare_layoutcommit           = bl_prepare_layoutcommit,
 978         .cleanup_layoutcommit           = bl_cleanup_layoutcommit,
 979         .set_layoutdriver               = bl_set_layoutdriver,
 980         .alloc_deviceid_node            = bl_alloc_deviceid_node,
 981         .free_deviceid_node             = bl_free_deviceid_node,
 982         .pg_read_ops                    = &bl_pg_read_ops,
 983         .pg_write_ops                   = &bl_pg_write_ops,
 984         .sync                           = pnfs_generic_sync,
 985 };
 986 
 987 static struct pnfs_layoutdriver_type scsilayout_type = {
 988         .id                             = LAYOUT_SCSI,
 989         .name                           = "LAYOUT_SCSI",
 990         .owner                          = THIS_MODULE,
 991         .flags                          = PNFS_LAYOUTRET_ON_SETATTR |
 992                                           PNFS_LAYOUTRET_ON_ERROR |
 993                                           PNFS_READ_WHOLE_PAGE,
 994         .read_pagelist                  = bl_read_pagelist,
 995         .write_pagelist                 = bl_write_pagelist,
 996         .alloc_layout_hdr               = sl_alloc_layout_hdr,
 997         .free_layout_hdr                = bl_free_layout_hdr,
 998         .alloc_lseg                     = bl_alloc_lseg,
 999         .free_lseg                      = bl_free_lseg,
1000         .return_range                   = bl_return_range,
1001         .prepare_layoutcommit           = bl_prepare_layoutcommit,
1002         .cleanup_layoutcommit           = bl_cleanup_layoutcommit,
1003         .set_layoutdriver               = bl_set_layoutdriver,
1004         .alloc_deviceid_node            = bl_alloc_deviceid_node,
1005         .free_deviceid_node             = bl_free_deviceid_node,
1006         .pg_read_ops                    = &bl_pg_read_ops,
1007         .pg_write_ops                   = &bl_pg_write_ops,
1008         .sync                           = pnfs_generic_sync,
1009 };
1010 
1011 
1012 static int __init nfs4blocklayout_init(void)
1013 {
1014         int ret;
1015 
1016         dprintk("%s: NFSv4 Block Layout Driver Registering...\n", __func__);
1017 
1018         ret = bl_init_pipefs();
1019         if (ret)
1020                 goto out;
1021 
1022         ret = pnfs_register_layoutdriver(&blocklayout_type);
1023         if (ret)
1024                 goto out_cleanup_pipe;
1025 
1026         ret = pnfs_register_layoutdriver(&scsilayout_type);
1027         if (ret)
1028                 goto out_unregister_block;
1029         return 0;
1030 
1031 out_unregister_block:
1032         pnfs_unregister_layoutdriver(&blocklayout_type);
1033 out_cleanup_pipe:
1034         bl_cleanup_pipefs();
1035 out:
1036         return ret;
1037 }
1038 
1039 static void __exit nfs4blocklayout_exit(void)
1040 {
1041         dprintk("%s: NFSv4 Block Layout Driver Unregistering...\n",
1042                __func__);
1043 
1044         pnfs_unregister_layoutdriver(&scsilayout_type);
1045         pnfs_unregister_layoutdriver(&blocklayout_type);
1046         bl_cleanup_pipefs();
1047 }
1048 
1049 MODULE_ALIAS("nfs-layouttype4-3");
1050 MODULE_ALIAS("nfs-layouttype4-5");
1051 
1052 module_init(nfs4blocklayout_init);
1053 module_exit(nfs4blocklayout_exit);