fs/ceph/file.c

   1 #include <linux/ceph/ceph_debug.h>
   2
   3 #include <linux/module.h>
   4 #include <linux/sched.h>
   5 #include <linux/slab.h>
   6 #include <linux/file.h>
   7 #include <linux/namei.h>
   8 #include <linux/writeback.h>
   9
  10 #include "super.h"
  11 #include "mds_client.h"
  12
  13 /*
  14  * Ceph file operations
  15  *
  16  * Implement basic open/close functionality, and implement
  17  * read/write.
  18  *
  19  * We implement three modes of file I/O:
  20  *  - buffered uses the generic_file_aio_{read,write} helpers
  21  *
  22  *  - synchronous is used when there is multi-client read/write
  23  *    sharing, avoids the page cache, and synchronously waits for an
  24  *    ack from the OSD.
  25  *
  26  *  - direct io takes the variant of the sync path that references
  27  *    user pages directly.
  28  *
  29  * fsync() flushes and waits on dirty pages, but just queues metadata
  30  * for writeback: since the MDS can recover size and mtime there is no
  31  * need to wait for MDS acknowledgement.
  32  */
  33
  34
  35 /*
  36  * Prepare an open request.  Preallocate ceph_cap to avoid an
  37  * inopportune ENOMEM later.
  38  */
  39 static struct ceph_mds_request *
  40 prepare_open_request(struct super_block *sb, int flags, int create_mode)
  41 {
  42         struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
  43         struct ceph_mds_client *mdsc = fsc->mdsc;
  44         struct ceph_mds_request *req;
  45         int want_auth = USE_ANY_MDS;
  46         int op = (flags & O_CREAT) ? CEPH_MDS_OP_CREATE : CEPH_MDS_OP_OPEN;
  47
  48         if (flags & (O_WRONLY|O_RDWR|O_CREAT|O_TRUNC))
  49                 want_auth = USE_AUTH_MDS;
  50
  51         req = ceph_mdsc_create_request(mdsc, op, want_auth);
  52         if (IS_ERR(req))
  53                 goto out;
  54         req->r_fmode = ceph_flags_to_mode(flags);
  55         req->r_args.open.flags = cpu_to_le32(flags);
  56         req->r_args.open.mode = cpu_to_le32(create_mode);
  57 out:
  58         return req;
  59 }
  60
  61 /*
  62  * initialize private struct file data.
  63  * if we fail, clean up by dropping fmode reference on the ceph_inode
  64  */
  65 static int ceph_init_file(struct inode *inode, struct file *file, int fmode)
  66 {
  67         struct ceph_file_info *cf;
  68         int ret = 0;
  69
  70         switch (inode->i_mode & S_IFMT) {
  71         case S_IFREG:
  72         case S_IFDIR:
  73                 dout("init_file %p %p 0%o (regular)\n", inode, file,
  74                      inode->i_mode);
  75                 cf = kmem_cache_alloc(ceph_file_cachep, GFP_NOFS | __GFP_ZERO);
  76                 if (cf == NULL) {
  77                         ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
  78                         return -ENOMEM;
  79                 }
  80                 cf->fmode = fmode;
  81                 cf->next_offset = 2;
  82                 file->private_data = cf;
  83                 BUG_ON(inode->i_fop->release != ceph_release);
  84                 break;
  85
  86         case S_IFLNK:
  87                 dout("init_file %p %p 0%o (symlink)\n", inode, file,
  88                      inode->i_mode);
  89                 ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
  90                 break;
  91
  92         default:
  93                 dout("init_file %p %p 0%o (special)\n", inode, file,
  94                      inode->i_mode);
  95                 /*
  96                  * we need to drop the open ref now, since we don't
  97                  * have .release set to ceph_release.
  98                  */
  99                 ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
 100                 BUG_ON(inode->i_fop->release == ceph_release);
 101
 102                 /* call the proper open fop */
 103                 ret = inode->i_fop->open(inode, file);
 104         }
 105         return ret;
 106 }
 107
 108 /*
 109  * If the filp already has private_data, that means the file was
 110  * already opened by intent during lookup, and we do nothing.
 111  *
 112  * If we already have the requisite capabilities, we can satisfy
 113  * the open request locally (no need to request new caps from the
 114  * MDS).  We do, however, need to inform the MDS (asynchronously)
 115  * if our wanted caps set expands.
 116  */
 117 int ceph_open(struct inode *inode, struct file *file)
 118 {
 119         struct ceph_inode_info *ci = ceph_inode(inode);
 120         struct ceph_fs_client *fsc = ceph_sb_to_client(inode->i_sb);
 121         struct ceph_mds_client *mdsc = fsc->mdsc;
 122         struct ceph_mds_request *req;
 123         struct ceph_file_info *cf = file->private_data;
 124         struct inode *parent_inode = NULL;
 125         int err;
 126         int flags, fmode, wanted;
 127
 128         if (cf) {
 129                 dout("open file %p is already opened\n", file);
 130                 return 0;
 131         }
 132
 133         /* filter out O_CREAT|O_EXCL; vfs did that already.  yuck. */
 134         flags = file->f_flags & ~(O_CREAT|O_EXCL);
 135         if (S_ISDIR(inode->i_mode))
 136                 flags = O_DIRECTORY;  /* mds likes to know */
 137
 138         dout("open inode %p ino %llx.%llx file %p flags %d (%d)\n", inode,
 139              ceph_vinop(inode), file, flags, file->f_flags);
 140         fmode = ceph_flags_to_mode(flags);
 141         wanted = ceph_caps_for_mode(fmode);
 142
 143         /* snapped files are read-only */
 144         if (ceph_snap(inode) != CEPH_NOSNAP && (file->f_mode & FMODE_WRITE))
 145                 return -EROFS;
 146
 147         /* trivially open snapdir */
 148         if (ceph_snap(inode) == CEPH_SNAPDIR) {
 149                 spin_lock(&ci->i_ceph_lock);
 150                 __ceph_get_fmode(ci, fmode);
 151                 spin_unlock(&ci->i_ceph_lock);
 152                 return ceph_init_file(inode, file, fmode);
 153         }
 154
 155         /*
 156          * No need to block if we have caps on the auth MDS (for
 157          * write) or any MDS (for read).  Update wanted set
 158          * asynchronously.
 159          */
 160         spin_lock(&ci->i_ceph_lock);
 161         if (__ceph_is_any_real_caps(ci) &&
 162             (((fmode & CEPH_FILE_MODE_WR) == 0) || ci->i_auth_cap)) {
 163                 int mds_wanted = __ceph_caps_mds_wanted(ci);
 164                 int issued = __ceph_caps_issued(ci, NULL);
 165
 166                 dout("open %p fmode %d want %s issued %s using existing\n",
 167                      inode, fmode, ceph_cap_string(wanted),
 168                      ceph_cap_string(issued));
 169                 __ceph_get_fmode(ci, fmode);
 170                 spin_unlock(&ci->i_ceph_lock);
 171
 172                 /* adjust wanted? */
 173                 if ((issued & wanted) != wanted &&
 174                     (mds_wanted & wanted) != wanted &&
 175                     ceph_snap(inode) != CEPH_SNAPDIR)
 176                         ceph_check_caps(ci, 0, NULL);
 177
 178                 return ceph_init_file(inode, file, fmode);
 179         } else if (ceph_snap(inode) != CEPH_NOSNAP &&
 180                    (ci->i_snap_caps & wanted) == wanted) {
 181                 __ceph_get_fmode(ci, fmode);
 182                 spin_unlock(&ci->i_ceph_lock);
 183                 return ceph_init_file(inode, file, fmode);
 184         }
 185         spin_unlock(&ci->i_ceph_lock);
 186
 187         dout("open fmode %d wants %s\n", fmode, ceph_cap_string(wanted));
 188         req = prepare_open_request(inode->i_sb, flags, 0);
 189         if (IS_ERR(req)) {
 190                 err = PTR_ERR(req);
 191                 goto out;
 192         }
 193         req->r_inode = inode;
 194         ihold(inode);
 195         req->r_num_caps = 1;
 196         if (flags & (O_CREAT|O_TRUNC))
 197                 parent_inode = ceph_get_dentry_parent_inode(file->f_dentry);
 198         err = ceph_mdsc_do_request(mdsc, parent_inode, req);
 199         iput(parent_inode);
 200         if (!err)
 201                 err = ceph_init_file(inode, file, req->r_fmode);
 202         ceph_mdsc_put_request(req);
 203         dout("open result=%d on %llx.%llx\n", err, ceph_vinop(inode));
 204 out:
 205         return err;
 206 }
 207
 208
 209 /*
 210  * Do a lookup + open with a single request.
 211  *
 212  * If this succeeds, but some subsequent check in the vfs
 213  * may_open() fails, the struct *file gets cleaned up (i.e.
 214  * ceph_release gets called).  So fear not!
 215  */
 216 int ceph_lookup_open(struct inode *dir, struct dentry *dentry,
 217                      struct file *file, unsigned flags, umode_t mode,
 218                      int *opened)
 219 {
 220         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
 221         struct ceph_mds_client *mdsc = fsc->mdsc;
 222         struct ceph_mds_request *req;
 223         struct dentry *ret;
 224         int err;
 225
 226         dout("ceph_lookup_open dentry %p '%.*s' flags %d mode 0%o\n",
 227              dentry, dentry->d_name.len, dentry->d_name.name, flags, mode);
 228
 229         /* do the open */
 230         req = prepare_open_request(dir->i_sb, flags, mode);
 231         if (IS_ERR(req))
 232                 return PTR_ERR(req);
 233         req->r_dentry = dget(dentry);
 234         req->r_num_caps = 2;
 235         if (flags & O_CREAT) {
 236                 req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
 237                 req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
 238         }
 239         req->r_locked_dir = dir;           /* caller holds dir->i_mutex */
 240         err = ceph_mdsc_do_request(mdsc,
 241                                    (flags & (O_CREAT|O_TRUNC)) ? dir : NULL,
 242                                    req);
 243         err = ceph_handle_snapdir(req, dentry, err);
 244         if (err)
 245                 goto out;
 246         if ((flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
 247                 err = ceph_handle_notrace_create(dir, dentry);
 248         if (err)
 249                 goto out;
 250         err = finish_open(file, req->r_dentry, ceph_open, opened);
 251 out:
 252         ret = ceph_finish_lookup(req, dentry, err);
 253         ceph_mdsc_put_request(req);
 254         dout("ceph_lookup_open result=%p\n", ret);
 255
 256         if (IS_ERR(ret))
 257                 return PTR_ERR(ret);
 258
 259         dput(ret);
 260         return err;
 261 }
 262
 263 int ceph_release(struct inode *inode, struct file *file)
 264 {
 265         struct ceph_inode_info *ci = ceph_inode(inode);
 266         struct ceph_file_info *cf = file->private_data;
 267
 268         dout("release inode %p file %p\n", inode, file);
 269         ceph_put_fmode(ci, cf->fmode);
 270         if (cf->last_readdir)
 271                 ceph_mdsc_put_request(cf->last_readdir);
 272         kfree(cf->last_name);
 273         kfree(cf->dir_info);
 274         dput(cf->dentry);
 275         kmem_cache_free(ceph_file_cachep, cf);
 276
 277         /* wake up anyone waiting for caps on this inode */
 278         wake_up_all(&ci->i_cap_wq);
 279         return 0;
 280 }
 281
 282 /*
 283  * Read a range of bytes striped over one or more objects.  Iterate over
 284  * objects we stripe over.  (That's not atomic, but good enough for now.)
 285  *
 286  * If we get a short result from the OSD, check against i_size; we need to
 287  * only return a short read to the caller if we hit EOF.
 288  */
 289 static int striped_read(struct inode *inode,
 290                         u64 off, u64 len,
 291                         struct page **pages, int num_pages,
 292                         int *checkeof, bool o_direct,
 293                         unsigned long buf_align)
 294 {
 295         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 296         struct ceph_inode_info *ci = ceph_inode(inode);
 297         u64 pos, this_len;
 298         int io_align, page_align;
 299         int left, pages_left;
 300         int read;
 301         struct page **page_pos;
 302         int ret;
 303         bool hit_stripe, was_short;
 304
 305         /*
 306          * we may need to do multiple reads.  not atomic, unfortunately.
 307          */
 308         pos = off;
 309         left = len;
 310         page_pos = pages;
 311         pages_left = num_pages;
 312         read = 0;
 313         io_align = off & ~PAGE_MASK;
 314
 315 more:
 316         if (o_direct)
 317                 page_align = (pos - io_align + buf_align) & ~PAGE_MASK;
 318         else
 319                 page_align = pos & ~PAGE_MASK;
 320         this_len = left;
 321         ret = ceph_osdc_readpages(&fsc->client->osdc, ceph_vino(inode),
 322                                   &ci->i_layout, pos, &this_len,
 323                                   ci->i_truncate_seq,
 324                                   ci->i_truncate_size,
 325                                   page_pos, pages_left, page_align);
 326         if (ret == -ENOENT)
 327                 ret = 0;
 328         hit_stripe = this_len < left;
 329         was_short = ret >= 0 && ret < this_len;
 330         dout("striped_read %llu~%u (read %u) got %d%s%s\n", pos, left, read,
 331              ret, hit_stripe ? " HITSTRIPE" : "", was_short ? " SHORT" : "");
 332
 333         if (ret > 0) {
 334                 int didpages = (page_align + ret) >> PAGE_CACHE_SHIFT;
 335
 336                 if (read < pos - off) {
 337                         dout(" zero gap %llu to %llu\n", off + read, pos);
 338                         ceph_zero_page_vector_range(page_align + read,
 339                                                     pos - off - read, pages);
 340                 }
 341                 pos += ret;
 342                 read = pos - off;
 343                 left -= ret;
 344                 page_pos += didpages;
 345                 pages_left -= didpages;
 346
 347                 /* hit stripe? */
 348                 if (left && hit_stripe)
 349                         goto more;
 350         }
 351
 352         if (was_short) {
 353                 /* did we bounce off eof? */
 354                 if (pos + left > inode->i_size)
 355                         *checkeof = 1;
 356
 357                 /* zero trailing bytes (inside i_size) */
 358                 if (left > 0 && pos < inode->i_size) {
 359                         if (pos + left > inode->i_size)
 360                                 left = inode->i_size - pos;
 361
 362                         dout("zero tail %d\n", left);
 363                         ceph_zero_page_vector_range(page_align + read, left,
 364                                                     pages);
 365                         read += left;
 366                 }
 367         }
 368
 369         if (ret >= 0)
 370                 ret = read;
 371         dout("striped_read returns %d\n", ret);
 372         return ret;
 373 }
 374
 375 /*
 376  * Completely synchronous read and write methods.  Direct from __user
 377  * buffer to osd, or directly to user pages (if O_DIRECT).
 378  *
 379  * If the read spans object boundary, just do multiple reads.
 380  */
 381 static ssize_t ceph_sync_read(struct file *file, char __user *data,
 382                               unsigned len, loff_t *poff, int *checkeof)
 383 {
 384         struct inode *inode = file->f_dentry->d_inode;
 385         struct page **pages;
 386         u64 off = *poff;
 387         int num_pages, ret;
 388
 389         dout("sync_read on file %p %llu~%u %s\n", file, off, len,
 390              (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
 391
 392         if (file->f_flags & O_DIRECT) {
 393                 num_pages = calc_pages_for((unsigned long)data, len);
 394                 pages = ceph_get_direct_page_vector(data, num_pages, true);
 395         } else {
 396                 num_pages = calc_pages_for(off, len);
 397                 pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
 398         }
 399         if (IS_ERR(pages))
 400                 return PTR_ERR(pages);
 401
 402         /*
 403          * flush any page cache pages in this range.  this
 404          * will make concurrent normal and sync io slow,
 405          * but it will at least behave sensibly when they are
 406          * in sequence.
 407          */
 408         ret = filemap_write_and_wait(inode->i_mapping);
 409         if (ret < 0)
 410                 goto done;
 411
 412         ret = striped_read(inode, off, len, pages, num_pages, checkeof,
 413                            file->f_flags & O_DIRECT,
 414                            (unsigned long)data & ~PAGE_MASK);
 415
 416         if (ret >= 0 && (file->f_flags & O_DIRECT) == 0)
 417                 ret = ceph_copy_page_vector_to_user(pages, data, off, ret);
 418         if (ret >= 0)
 419                 *poff = off + ret;
 420
 421 done:
 422         if (file->f_flags & O_DIRECT)
 423                 ceph_put_page_vector(pages, num_pages, true);
 424         else
 425                 ceph_release_page_vector(pages, num_pages);
 426         dout("sync_read result %d\n", ret);
 427         return ret;
 428 }
 429
 430 /*
 431  * Write commit callback, called if we requested both an ACK and
 432  * ONDISK commit reply from the OSD.
 433  */
 434 static void sync_write_commit(struct ceph_osd_request *req,
 435                               struct ceph_msg *msg)
 436 {
 437         struct ceph_inode_info *ci = ceph_inode(req->r_inode);
 438
 439         dout("sync_write_commit %p tid %llu\n", req, req->r_tid);
 440         spin_lock(&ci->i_unsafe_lock);
 441         list_del_init(&req->r_unsafe_item);
 442         spin_unlock(&ci->i_unsafe_lock);
 443         ceph_put_cap_refs(ci, CEPH_CAP_FILE_WR);
 444 }
 445
 446 /*
 447  * Synchronous write, straight from __user pointer or user pages (if
 448  * O_DIRECT).
 449  *
 450  * If write spans object boundary, just do multiple writes.  (For a
 451  * correct atomic write, we should e.g. take write locks on all
 452  * objects, rollback on failure, etc.)
 453  */
 454 static ssize_t ceph_sync_write(struct file *file, const char __user *data,
 455                                size_t left, loff_t *offset)
 456 {
 457         struct inode *inode = file->f_dentry->d_inode;
 458         struct ceph_inode_info *ci = ceph_inode(inode);
 459         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 460         struct ceph_osd_request *req;
 461         struct page **pages;
 462         int num_pages;
 463         long long unsigned pos;
 464         u64 len;
 465         int written = 0;
 466         int flags;
 467         int do_sync = 0;
 468         int check_caps = 0;
 469         int page_align, io_align;
 470         unsigned long buf_align;
 471         int ret;
 472         struct timespec mtime = CURRENT_TIME;
 473
 474         if (ceph_snap(file->f_dentry->d_inode) != CEPH_NOSNAP)
 475                 return -EROFS;
 476
 477         dout("sync_write on file %p %lld~%u %s\n", file, *offset,
 478              (unsigned)left, (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
 479
 480         if (file->f_flags & O_APPEND)
 481                 pos = i_size_read(inode);
 482         else
 483                 pos = *offset;
 484
 485         ret = filemap_write_and_wait_range(inode->i_mapping, pos, pos + left);
 486         if (ret < 0)
 487                 return ret;
 488
 489         ret = invalidate_inode_pages2_range(inode->i_mapping,
 490                                             pos >> PAGE_CACHE_SHIFT,
 491                                             (pos + left) >> PAGE_CACHE_SHIFT);
 492         if (ret < 0)
 493                 dout("invalidate_inode_pages2_range returned %d\n", ret);
 494
 495         flags = CEPH_OSD_FLAG_ORDERSNAP |
 496                 CEPH_OSD_FLAG_ONDISK |
 497                 CEPH_OSD_FLAG_WRITE;
 498         if ((file->f_flags & (O_SYNC|O_DIRECT)) == 0)
 499                 flags |= CEPH_OSD_FLAG_ACK;
 500         else
 501                 do_sync = 1;
 502
 503         /*
 504          * we may need to do multiple writes here if we span an object
 505          * boundary.  this isn't atomic, unfortunately.  :(
 506          */
 507 more:
 508         io_align = pos & ~PAGE_MASK;
 509         buf_align = (unsigned long)data & ~PAGE_MASK;
 510         len = left;
 511         if (file->f_flags & O_DIRECT) {
 512                 /* write from beginning of first page, regardless of
 513                    io alignment */
 514                 page_align = (pos - io_align + buf_align) & ~PAGE_MASK;
 515                 num_pages = calc_pages_for((unsigned long)data, len);
 516         } else {
 517                 page_align = pos & ~PAGE_MASK;
 518                 num_pages = calc_pages_for(pos, len);
 519         }
 520         req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
 521                                     ceph_vino(inode), pos, &len,
 522                                     CEPH_OSD_OP_WRITE, flags,
 523                                     ci->i_snap_realm->cached_context,
 524                                     do_sync,
 525                                     ci->i_truncate_seq, ci->i_truncate_size,
 526                                     &mtime, false, 2, page_align);
 527         if (!req)
 528                 return -ENOMEM;
 529
 530         if (file->f_flags & O_DIRECT) {
 531                 pages = ceph_get_direct_page_vector(data, num_pages, false);
 532                 if (IS_ERR(pages)) {
 533                         ret = PTR_ERR(pages);
 534                         goto out;
 535                 }
 536
 537                 /*
 538                  * throw out any page cache pages in this range. this
 539                  * may block.
 540                  */
 541                 truncate_inode_pages_range(inode->i_mapping, pos,
 542                                            (pos+len) | (PAGE_CACHE_SIZE-1));
 543         } else {
 544                 pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
 545                 if (IS_ERR(pages)) {
 546                         ret = PTR_ERR(pages);
 547                         goto out;
 548                 }
 549                 ret = ceph_copy_user_to_page_vector(pages, data, pos, len);
 550                 if (ret < 0) {
 551                         ceph_release_page_vector(pages, num_pages);
 552                         goto out;
 553                 }
 554
 555                 if ((file->f_flags & O_SYNC) == 0) {
 556                         /* get a second commit callback */
 557                         req->r_safe_callback = sync_write_commit;
 558                         req->r_own_pages = 1;
 559                 }
 560         }
 561         req->r_pages = pages;
 562         req->r_num_pages = num_pages;
 563         req->r_inode = inode;
 564
 565         ret = ceph_osdc_start_request(&fsc->client->osdc, req, false);
 566         if (!ret) {
 567                 if (req->r_safe_callback) {
 568                         /*
 569                          * Add to inode unsafe list only after we
 570                          * start_request so that a tid has been assigned.
 571                          */
 572                         spin_lock(&ci->i_unsafe_lock);
 573                         list_add_tail(&req->r_unsafe_item,
 574                                       &ci->i_unsafe_writes);
 575                         spin_unlock(&ci->i_unsafe_lock);
 576                         ceph_get_cap_refs(ci, CEPH_CAP_FILE_WR);
 577                 }
 578
 579                 ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
 580                 if (ret < 0 && req->r_safe_callback) {
 581                         spin_lock(&ci->i_unsafe_lock);
 582                         list_del_init(&req->r_unsafe_item);
 583                         spin_unlock(&ci->i_unsafe_lock);
 584                         ceph_put_cap_refs(ci, CEPH_CAP_FILE_WR);
 585                 }
 586         }
 587
 588         if (file->f_flags & O_DIRECT)
 589                 ceph_put_page_vector(pages, num_pages, false);
 590         else if (file->f_flags & O_SYNC)
 591                 ceph_release_page_vector(pages, num_pages);
 592
 593 out:
 594         ceph_osdc_put_request(req);
 595         if (ret == 0) {
 596                 pos += len;
 597                 written += len;
 598                 left -= len;
 599                 data += written;
 600                 if (left)
 601                         goto more;
 602
 603                 ret = written;
 604                 *offset = pos;
 605                 if (pos > i_size_read(inode))
 606                         check_caps = ceph_inode_set_size(inode, pos);
 607                 if (check_caps)
 608                         ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY,
 609                                         NULL);
 610         }
 611         return ret;
 612 }
 613
 614 /*
 615  * Wrap generic_file_aio_read with checks for cap bits on the inode.
 616  * Atomically grab references, so that those bits are not released
 617  * back to the MDS mid-read.
 618  *
 619  * Hmm, the sync read case isn't actually async... should it be?
 620  */
 621 static ssize_t ceph_aio_read(struct kiocb *iocb, const struct iovec *iov,
 622                              unsigned long nr_segs, loff_t pos)
 623 {
 624         struct file *filp = iocb->ki_filp;
 625         struct ceph_file_info *fi = filp->private_data;
 626         loff_t *ppos = &iocb->ki_pos;
 627         size_t len = iov->iov_len;
 628         struct inode *inode = filp->f_dentry->d_inode;
 629         struct ceph_inode_info *ci = ceph_inode(inode);
 630         void __user *base = iov->iov_base;
 631         ssize_t ret;
 632         int want, got = 0;
 633         int checkeof = 0, read = 0;
 634
 635         dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n",
 636              inode, ceph_vinop(inode), pos, (unsigned)len, inode);
 637 again:
 638         __ceph_do_pending_vmtruncate(inode);
 639         if (fi->fmode & CEPH_FILE_MODE_LAZY)
 640                 want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
 641         else
 642                 want = CEPH_CAP_FILE_CACHE;
 643         ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want, &got, -1);
 644         if (ret < 0)
 645                 goto out;
 646         dout("aio_read %p %llx.%llx %llu~%u got cap refs on %s\n",
 647              inode, ceph_vinop(inode), pos, (unsigned)len,
 648              ceph_cap_string(got));
 649
 650         if ((got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0 ||
 651             (iocb->ki_filp->f_flags & O_DIRECT) ||
 652             (inode->i_sb->s_flags & MS_SYNCHRONOUS) ||
 653             (fi->flags & CEPH_F_SYNC))
 654                 /* hmm, this isn't really async... */
 655                 ret = ceph_sync_read(filp, base, len, ppos, &checkeof);
 656         else
 657                 ret = generic_file_aio_read(iocb, iov, nr_segs, pos);
 658
 659 out:
 660         dout("aio_read %p %llx.%llx dropping cap refs on %s = %d\n",
 661              inode, ceph_vinop(inode), ceph_cap_string(got), (int)ret);
 662         ceph_put_cap_refs(ci, got);
 663
 664         if (checkeof && ret >= 0) {
 665                 int statret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE);
 666
 667                 /* hit EOF or hole? */
 668                 if (statret == 0 && *ppos < inode->i_size) {
 669                         dout("aio_read sync_read hit hole, ppos %lld < size %lld, reading more\n", *ppos, inode->i_size);
 670                         read += ret;
 671                         base += ret;
 672                         len -= ret;
 673                         checkeof = 0;
 674                         goto again;
 675                 }
 676         }
 677         if (ret >= 0)
 678                 ret += read;
 679
 680         return ret;
 681 }
 682
 683 /*
 684  * Take cap references to avoid releasing caps to MDS mid-write.
 685  *
 686  * If we are synchronous, and write with an old snap context, the OSD
 687  * may return EOLDSNAPC.  In that case, retry the write.. _after_
 688  * dropping our cap refs and allowing the pending snap to logically
 689  * complete _before_ this write occurs.
 690  *
 691  * If we are near ENOSPC, write synchronously.
 692  */
 693 static ssize_t ceph_aio_write(struct kiocb *iocb, const struct iovec *iov,
 694                        unsigned long nr_segs, loff_t pos)
 695 {
 696         struct file *file = iocb->ki_filp;
 697         struct ceph_file_info *fi = file->private_data;
 698         struct inode *inode = file->f_dentry->d_inode;
 699         struct ceph_inode_info *ci = ceph_inode(inode);
 700         struct ceph_osd_client *osdc =
 701                 &ceph_sb_to_client(inode->i_sb)->client->osdc;
 702         loff_t endoff = pos + iov->iov_len;
 703         int want, got = 0;
 704         int ret, err;
 705
 706         if (ceph_snap(inode) != CEPH_NOSNAP)
 707                 return -EROFS;
 708
 709 retry_snap:
 710         if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL))
 711                 return -ENOSPC;
 712         __ceph_do_pending_vmtruncate(inode);
 713         dout("aio_write %p %llx.%llx %llu~%u getting caps. i_size %llu\n",
 714              inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
 715              inode->i_size);
 716         if (fi->fmode & CEPH_FILE_MODE_LAZY)
 717                 want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
 718         else
 719                 want = CEPH_CAP_FILE_BUFFER;
 720         ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, &got, endoff);
 721         if (ret < 0)
 722                 goto out_put;
 723
 724         dout("aio_write %p %llx.%llx %llu~%u  got cap refs on %s\n",
 725              inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
 726              ceph_cap_string(got));
 727
 728         if ((got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO)) == 0 ||
 729             (iocb->ki_filp->f_flags & O_DIRECT) ||
 730             (inode->i_sb->s_flags & MS_SYNCHRONOUS) ||
 731             (fi->flags & CEPH_F_SYNC)) {
 732                 ret = ceph_sync_write(file, iov->iov_base, iov->iov_len,
 733                         &iocb->ki_pos);
 734         } else {
 735                 /*
 736                  * buffered write; drop Fw early to avoid slow
 737                  * revocation if we get stuck on balance_dirty_pages
 738                  */
 739                 int dirty;
 740
 741                 spin_lock(&ci->i_ceph_lock);
 742                 dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
 743                 spin_unlock(&ci->i_ceph_lock);
 744                 ceph_put_cap_refs(ci, got);
 745
 746                 ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
 747                 if ((ret >= 0 || ret == -EIOCBQUEUED) &&
 748                     ((file->f_flags & O_SYNC) || IS_SYNC(file->f_mapping->host)
 749                      || ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_NEARFULL))) {
 750                         err = vfs_fsync_range(file, pos, pos + ret - 1, 1);
 751                         if (err < 0)
 752                                 ret = err;
 753                 }
 754
 755                 if (dirty)
 756                         __mark_inode_dirty(inode, dirty);
 757                 goto out;
 758         }
 759
 760         if (ret >= 0) {
 761                 int dirty;
 762                 spin_lock(&ci->i_ceph_lock);
 763                 dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
 764                 spin_unlock(&ci->i_ceph_lock);
 765                 if (dirty)
 766                         __mark_inode_dirty(inode, dirty);
 767         }
 768
 769 out_put:
 770         dout("aio_write %p %llx.%llx %llu~%u  dropping cap refs on %s\n",
 771              inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
 772              ceph_cap_string(got));
 773         ceph_put_cap_refs(ci, got);
 774
 775 out:
 776         if (ret == -EOLDSNAPC) {
 777                 dout("aio_write %p %llx.%llx %llu~%u got EOLDSNAPC, retrying\n",
 778                      inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len);
 779                 goto retry_snap;
 780         }
 781
 782         return ret;
 783 }
 784
 785 /*
 786  * llseek.  be sure to verify file size on SEEK_END.
 787  */
 788 static loff_t ceph_llseek(struct file *file, loff_t offset, int origin)
 789 {
 790         struct inode *inode = file->f_mapping->host;
 791         int ret;
 792
 793         mutex_lock(&inode->i_mutex);
 794         __ceph_do_pending_vmtruncate(inode);
 795
 796         if (origin == SEEK_END || origin == SEEK_DATA || origin == SEEK_HOLE) {
 797                 ret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE);
 798                 if (ret < 0) {
 799                         offset = ret;
 800                         goto out;
 801                 }
 802         }
 803
 804         switch (origin) {
 805         case SEEK_END:
 806                 offset += inode->i_size;
 807                 break;
 808         case SEEK_CUR:
 809                 /*
 810                  * Here we special-case the lseek(fd, 0, SEEK_CUR)
 811                  * position-querying operation.  Avoid rewriting the "same"
 812                  * f_pos value back to the file because a concurrent read(),
 813                  * write() or lseek() might have altered it
 814                  */
 815                 if (offset == 0) {
 816                         offset = file->f_pos;
 817                         goto out;
 818                 }
 819                 offset += file->f_pos;
 820                 break;
 821         case SEEK_DATA:
 822                 if (offset >= inode->i_size) {
 823                         ret = -ENXIO;
 824                         goto out;
 825                 }
 826                 break;
 827         case SEEK_HOLE:
 828                 if (offset >= inode->i_size) {
 829                         ret = -ENXIO;
 830                         goto out;
 831                 }
 832                 offset = inode->i_size;
 833                 break;
 834         }
 835
 836         if (offset < 0 || offset > inode->i_sb->s_maxbytes) {
 837                 offset = -EINVAL;
 838                 goto out;
 839         }
 840
 841         /* Special lock needed here? */
 842         if (offset != file->f_pos) {
 843                 file->f_pos = offset;
 844                 file->f_version = 0;
 845         }
 846
 847 out:
 848         mutex_unlock(&inode->i_mutex);
 849         return offset;
 850 }
 851
 852 const struct file_operations ceph_file_fops = {
 853         .open = ceph_open,
 854         .release = ceph_release,
 855         .llseek = ceph_llseek,
 856         .read = do_sync_read,
 857         .write = do_sync_write,
 858         .aio_read = ceph_aio_read,
 859         .aio_write = ceph_aio_write,
 860         .mmap = ceph_mmap,
 861         .fsync = ceph_fsync,
 862         .lock = ceph_lock,
 863         .flock = ceph_flock,
 864         .splice_read = generic_file_splice_read,
 865         .splice_write = generic_file_splice_write,
 866         .unlocked_ioctl = ceph_ioctl,
 867         .compat_ioctl   = ceph_ioctl,
 868 };
 869