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