fs/ceph/dir.c

   1 #include <linux/ceph/ceph_debug.h>
   2
   3 #include <linux/spinlock.h>
   4 #include <linux/fs_struct.h>
   5 #include <linux/namei.h>
   6 #include <linux/slab.h>
   7 #include <linux/sched.h>
   8 #include <linux/xattr.h>
   9
  10 #include "super.h"
  11 #include "mds_client.h"
  12
  13 /*
  14  * Directory operations: readdir, lookup, create, link, unlink,
  15  * rename, etc.
  16  */
  17
  18 /*
  19  * Ceph MDS operations are specified in terms of a base ino and
  20  * relative path.  Thus, the client can specify an operation on a
  21  * specific inode (e.g., a getattr due to fstat(2)), or as a path
  22  * relative to, say, the root directory.
  23  *
  24  * Normally, we limit ourselves to strict inode ops (no path component)
  25  * or dentry operations (a single path component relative to an ino).  The
  26  * exception to this is open_root_dentry(), which will open the mount
  27  * point by name.
  28  */
  29
  30 const struct dentry_operations ceph_dentry_ops;
  31
  32 /*
  33  * Initialize ceph dentry state.
  34  */
  35 static int ceph_d_init(struct dentry *dentry)
  36 {
  37         struct ceph_dentry_info *di;
  38
  39         di = kmem_cache_zalloc(ceph_dentry_cachep, GFP_KERNEL);
  40         if (!di)
  41                 return -ENOMEM;          /* oh well */
  42
  43         di->dentry = dentry;
  44         di->lease_session = NULL;
  45         di->time = jiffies;
  46         dentry->d_fsdata = di;
  47         ceph_dentry_lru_add(dentry);
  48         return 0;
  49 }
  50
  51 /*
  52  * for f_pos for readdir:
  53  * - hash order:
  54  *      (0xff << 52) | ((24 bits hash) << 28) |
  55  *      (the nth entry has hash collision);
  56  * - frag+name order;
  57  *      ((frag value) << 28) | (the nth entry in frag);
  58  */
  59 #define OFFSET_BITS     28
  60 #define OFFSET_MASK     ((1 << OFFSET_BITS) - 1)
  61 #define HASH_ORDER      (0xffull << (OFFSET_BITS + 24))
  62 loff_t ceph_make_fpos(unsigned high, unsigned off, bool hash_order)
  63 {
  64         loff_t fpos = ((loff_t)high << 28) | (loff_t)off;
  65         if (hash_order)
  66                 fpos |= HASH_ORDER;
  67         return fpos;
  68 }
  69
  70 static bool is_hash_order(loff_t p)
  71 {
  72         return (p & HASH_ORDER) == HASH_ORDER;
  73 }
  74
  75 static unsigned fpos_frag(loff_t p)
  76 {
  77         return p >> OFFSET_BITS;
  78 }
  79
  80 static unsigned fpos_hash(loff_t p)
  81 {
  82         return ceph_frag_value(fpos_frag(p));
  83 }
  84
  85 static unsigned fpos_off(loff_t p)
  86 {
  87         return p & OFFSET_MASK;
  88 }
  89
  90 static int fpos_cmp(loff_t l, loff_t r)
  91 {
  92         int v = ceph_frag_compare(fpos_frag(l), fpos_frag(r));
  93         if (v)
  94                 return v;
  95         return (int)(fpos_off(l) - fpos_off(r));
  96 }
  97
  98 /*
  99  * make note of the last dentry we read, so we can
 100  * continue at the same lexicographical point,
 101  * regardless of what dir changes take place on the
 102  * server.
 103  */
 104 static int note_last_dentry(struct ceph_file_info *fi, const char *name,
 105                             int len, unsigned next_offset)
 106 {
 107         char *buf = kmalloc(len+1, GFP_KERNEL);
 108         if (!buf)
 109                 return -ENOMEM;
 110         kfree(fi->last_name);
 111         fi->last_name = buf;
 112         memcpy(fi->last_name, name, len);
 113         fi->last_name[len] = 0;
 114         fi->next_offset = next_offset;
 115         dout("note_last_dentry '%s'\n", fi->last_name);
 116         return 0;
 117 }
 118
 119
 120 static struct dentry *
 121 __dcache_find_get_entry(struct dentry *parent, u64 idx,
 122                         struct ceph_readdir_cache_control *cache_ctl)
 123 {
 124         struct inode *dir = d_inode(parent);
 125         struct dentry *dentry;
 126         unsigned idx_mask = (PAGE_SIZE / sizeof(struct dentry *)) - 1;
 127         loff_t ptr_pos = idx * sizeof(struct dentry *);
 128         pgoff_t ptr_pgoff = ptr_pos >> PAGE_SHIFT;
 129
 130         if (ptr_pos >= i_size_read(dir))
 131                 return NULL;
 132
 133         if (!cache_ctl->page || ptr_pgoff != page_index(cache_ctl->page)) {
 134                 ceph_readdir_cache_release(cache_ctl);
 135                 cache_ctl->page = find_lock_page(&dir->i_data, ptr_pgoff);
 136                 if (!cache_ctl->page) {
 137                         dout(" page %lu not found\n", ptr_pgoff);
 138                         return ERR_PTR(-EAGAIN);
 139                 }
 140                 /* reading/filling the cache are serialized by
 141                    i_mutex, no need to use page lock */
 142                 unlock_page(cache_ctl->page);
 143                 cache_ctl->dentries = kmap(cache_ctl->page);
 144         }
 145
 146         cache_ctl->index = idx & idx_mask;
 147
 148         rcu_read_lock();
 149         spin_lock(&parent->d_lock);
 150         /* check i_size again here, because empty directory can be
 151          * marked as complete while not holding the i_mutex. */
 152         if (ceph_dir_is_complete_ordered(dir) && ptr_pos < i_size_read(dir))
 153                 dentry = cache_ctl->dentries[cache_ctl->index];
 154         else
 155                 dentry = NULL;
 156         spin_unlock(&parent->d_lock);
 157         if (dentry && !lockref_get_not_dead(&dentry->d_lockref))
 158                 dentry = NULL;
 159         rcu_read_unlock();
 160         return dentry ? : ERR_PTR(-EAGAIN);
 161 }
 162
 163 /*
 164  * When possible, we try to satisfy a readdir by peeking at the
 165  * dcache.  We make this work by carefully ordering dentries on
 166  * d_child when we initially get results back from the MDS, and
 167  * falling back to a "normal" sync readdir if any dentries in the dir
 168  * are dropped.
 169  *
 170  * Complete dir indicates that we have all dentries in the dir.  It is
 171  * defined IFF we hold CEPH_CAP_FILE_SHARED (which will be revoked by
 172  * the MDS if/when the directory is modified).
 173  */
 174 static int __dcache_readdir(struct file *file,  struct dir_context *ctx,
 175                             u32 shared_gen)
 176 {
 177         struct ceph_file_info *fi = file->private_data;
 178         struct dentry *parent = file->f_path.dentry;
 179         struct inode *dir = d_inode(parent);
 180         struct dentry *dentry, *last = NULL;
 181         struct ceph_dentry_info *di;
 182         struct ceph_readdir_cache_control cache_ctl = {};
 183         u64 idx = 0;
 184         int err = 0;
 185
 186         dout("__dcache_readdir %p v%u at %llx\n", dir, shared_gen, ctx->pos);
 187
 188         /* search start position */
 189         if (ctx->pos > 2) {
 190                 u64 count = div_u64(i_size_read(dir), sizeof(struct dentry *));
 191                 while (count > 0) {
 192                         u64 step = count >> 1;
 193                         dentry = __dcache_find_get_entry(parent, idx + step,
 194                                                          &cache_ctl);
 195                         if (!dentry) {
 196                                 /* use linar search */
 197                                 idx = 0;
 198                                 break;
 199                         }
 200                         if (IS_ERR(dentry)) {
 201                                 err = PTR_ERR(dentry);
 202                                 goto out;
 203                         }
 204                         di = ceph_dentry(dentry);
 205                         spin_lock(&dentry->d_lock);
 206                         if (fpos_cmp(di->offset, ctx->pos) < 0) {
 207                                 idx += step + 1;
 208                                 count -= step + 1;
 209                         } else {
 210                                 count = step;
 211                         }
 212                         spin_unlock(&dentry->d_lock);
 213                         dput(dentry);
 214                 }
 215
 216                 dout("__dcache_readdir %p cache idx %llu\n", dir, idx);
 217         }
 218
 219
 220         for (;;) {
 221                 bool emit_dentry = false;
 222                 dentry = __dcache_find_get_entry(parent, idx++, &cache_ctl);
 223                 if (!dentry) {
 224                         fi->flags |= CEPH_F_ATEND;
 225                         err = 0;
 226                         break;
 227                 }
 228                 if (IS_ERR(dentry)) {
 229                         err = PTR_ERR(dentry);
 230                         goto out;
 231                 }
 232
 233                 di = ceph_dentry(dentry);
 234                 spin_lock(&dentry->d_lock);
 235                 if (di->lease_shared_gen == shared_gen &&
 236                     d_really_is_positive(dentry) &&
 237                     fpos_cmp(ctx->pos, di->offset) <= 0) {
 238                         emit_dentry = true;
 239                 }
 240                 spin_unlock(&dentry->d_lock);
 241
 242                 if (emit_dentry) {
 243                         dout(" %llx dentry %p %pd %p\n", di->offset,
 244                              dentry, dentry, d_inode(dentry));
 245                         ctx->pos = di->offset;
 246                         if (!dir_emit(ctx, dentry->d_name.name,
 247                                       dentry->d_name.len,
 248                                       ceph_translate_ino(dentry->d_sb,
 249                                                          d_inode(dentry)->i_ino),
 250                                       d_inode(dentry)->i_mode >> 12)) {
 251                                 dput(dentry);
 252                                 err = 0;
 253                                 break;
 254                         }
 255                         ctx->pos++;
 256
 257                         if (last)
 258                                 dput(last);
 259                         last = dentry;
 260                 } else {
 261                         dput(dentry);
 262                 }
 263         }
 264 out:
 265         ceph_readdir_cache_release(&cache_ctl);
 266         if (last) {
 267                 int ret;
 268                 di = ceph_dentry(last);
 269                 ret = note_last_dentry(fi, last->d_name.name, last->d_name.len,
 270                                        fpos_off(di->offset) + 1);
 271                 if (ret < 0)
 272                         err = ret;
 273                 dput(last);
 274                 /* last_name no longer match cache index */
 275                 if (fi->readdir_cache_idx >= 0) {
 276                         fi->readdir_cache_idx = -1;
 277                         fi->dir_release_count = 0;
 278                 }
 279         }
 280         return err;
 281 }
 282
 283 static bool need_send_readdir(struct ceph_file_info *fi, loff_t pos)
 284 {
 285         if (!fi->last_readdir)
 286                 return true;
 287         if (is_hash_order(pos))
 288                 return !ceph_frag_contains_value(fi->frag, fpos_hash(pos));
 289         else
 290                 return fi->frag != fpos_frag(pos);
 291 }
 292
 293 static int ceph_readdir(struct file *file, struct dir_context *ctx)
 294 {
 295         struct ceph_file_info *fi = file->private_data;
 296         struct inode *inode = file_inode(file);
 297         struct ceph_inode_info *ci = ceph_inode(inode);
 298         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 299         struct ceph_mds_client *mdsc = fsc->mdsc;
 300         int i;
 301         int err;
 302         unsigned frag = -1;
 303         struct ceph_mds_reply_info_parsed *rinfo;
 304
 305         dout("readdir %p file %p pos %llx\n", inode, file, ctx->pos);
 306         if (fi->flags & CEPH_F_ATEND)
 307                 return 0;
 308
 309         /* always start with . and .. */
 310         if (ctx->pos == 0) {
 311                 dout("readdir off 0 -> '.'\n");
 312                 if (!dir_emit(ctx, ".", 1,
 313                             ceph_translate_ino(inode->i_sb, inode->i_ino),
 314                             inode->i_mode >> 12))
 315                         return 0;
 316                 ctx->pos = 1;
 317         }
 318         if (ctx->pos == 1) {
 319                 ino_t ino = parent_ino(file->f_path.dentry);
 320                 dout("readdir off 1 -> '..'\n");
 321                 if (!dir_emit(ctx, "..", 2,
 322                             ceph_translate_ino(inode->i_sb, ino),
 323                             inode->i_mode >> 12))
 324                         return 0;
 325                 ctx->pos = 2;
 326         }
 327
 328         /* can we use the dcache? */
 329         spin_lock(&ci->i_ceph_lock);
 330         if (ceph_test_mount_opt(fsc, DCACHE) &&
 331             !ceph_test_mount_opt(fsc, NOASYNCREADDIR) &&
 332             ceph_snap(inode) != CEPH_SNAPDIR &&
 333             __ceph_dir_is_complete_ordered(ci) &&
 334             __ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1)) {
 335                 u32 shared_gen = ci->i_shared_gen;
 336                 spin_unlock(&ci->i_ceph_lock);
 337                 err = __dcache_readdir(file, ctx, shared_gen);
 338                 if (err != -EAGAIN)
 339                         return err;
 340         } else {
 341                 spin_unlock(&ci->i_ceph_lock);
 342         }
 343
 344         /* proceed with a normal readdir */
 345 more:
 346         /* do we have the correct frag content buffered? */
 347         if (need_send_readdir(fi, ctx->pos)) {
 348                 struct ceph_mds_request *req;
 349                 int op = ceph_snap(inode) == CEPH_SNAPDIR ?
 350                         CEPH_MDS_OP_LSSNAP : CEPH_MDS_OP_READDIR;
 351
 352                 /* discard old result, if any */
 353                 if (fi->last_readdir) {
 354                         ceph_mdsc_put_request(fi->last_readdir);
 355                         fi->last_readdir = NULL;
 356                 }
 357
 358                 if (is_hash_order(ctx->pos)) {
 359                         /* fragtree isn't always accurate. choose frag
 360                          * based on previous reply when possible. */
 361                         if (frag == (unsigned)-1)
 362                                 frag = ceph_choose_frag(ci, fpos_hash(ctx->pos),
 363                                                         NULL, NULL);
 364                 } else {
 365                         frag = fpos_frag(ctx->pos);
 366                 }
 367
 368                 dout("readdir fetching %llx.%llx frag %x offset '%s'\n",
 369                      ceph_vinop(inode), frag, fi->last_name);
 370                 req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
 371                 if (IS_ERR(req))
 372                         return PTR_ERR(req);
 373                 err = ceph_alloc_readdir_reply_buffer(req, inode);
 374                 if (err) {
 375                         ceph_mdsc_put_request(req);
 376                         return err;
 377                 }
 378                 /* hints to request -> mds selection code */
 379                 req->r_direct_mode = USE_AUTH_MDS;
 380                 if (op == CEPH_MDS_OP_READDIR) {
 381                         req->r_direct_hash = ceph_frag_value(frag);
 382                         __set_bit(CEPH_MDS_R_DIRECT_IS_HASH, &req->r_req_flags);
 383                 }
 384                 if (fi->last_name) {
 385                         req->r_path2 = kstrdup(fi->last_name, GFP_KERNEL);
 386                         if (!req->r_path2) {
 387                                 ceph_mdsc_put_request(req);
 388                                 return -ENOMEM;
 389                         }
 390                 } else if (is_hash_order(ctx->pos)) {
 391                         req->r_args.readdir.offset_hash =
 392                                 cpu_to_le32(fpos_hash(ctx->pos));
 393                 }
 394
 395                 req->r_dir_release_cnt = fi->dir_release_count;
 396                 req->r_dir_ordered_cnt = fi->dir_ordered_count;
 397                 req->r_readdir_cache_idx = fi->readdir_cache_idx;
 398                 req->r_readdir_offset = fi->next_offset;
 399                 req->r_args.readdir.frag = cpu_to_le32(frag);
 400                 req->r_args.readdir.flags =
 401                                 cpu_to_le16(CEPH_READDIR_REPLY_BITFLAGS);
 402
 403                 req->r_inode = inode;
 404                 ihold(inode);
 405                 req->r_dentry = dget(file->f_path.dentry);
 406                 err = ceph_mdsc_do_request(mdsc, NULL, req);
 407                 if (err < 0) {
 408                         ceph_mdsc_put_request(req);
 409                         return err;
 410                 }
 411                 dout("readdir got and parsed readdir result=%d on "
 412                      "frag %x, end=%d, complete=%d, hash_order=%d\n",
 413                      err, frag,
 414                      (int)req->r_reply_info.dir_end,
 415                      (int)req->r_reply_info.dir_complete,
 416                      (int)req->r_reply_info.hash_order);
 417
 418                 rinfo = &req->r_reply_info;
 419                 if (le32_to_cpu(rinfo->dir_dir->frag) != frag) {
 420                         frag = le32_to_cpu(rinfo->dir_dir->frag);
 421                         if (!rinfo->hash_order) {
 422                                 fi->next_offset = req->r_readdir_offset;
 423                                 /* adjust ctx->pos to beginning of frag */
 424                                 ctx->pos = ceph_make_fpos(frag,
 425                                                           fi->next_offset,
 426                                                           false);
 427                         }
 428                 }
 429
 430                 fi->frag = frag;
 431                 fi->last_readdir = req;
 432
 433                 if (test_bit(CEPH_MDS_R_DID_PREPOPULATE, &req->r_req_flags)) {
 434                         fi->readdir_cache_idx = req->r_readdir_cache_idx;
 435                         if (fi->readdir_cache_idx < 0) {
 436                                 /* preclude from marking dir ordered */
 437                                 fi->dir_ordered_count = 0;
 438                         } else if (ceph_frag_is_leftmost(frag) &&
 439                                    fi->next_offset == 2) {
 440                                 /* note dir version at start of readdir so
 441                                  * we can tell if any dentries get dropped */
 442                                 fi->dir_release_count = req->r_dir_release_cnt;
 443                                 fi->dir_ordered_count = req->r_dir_ordered_cnt;
 444                         }
 445                 } else {
 446                         dout("readdir !did_prepopulate");
 447                         /* disable readdir cache */
 448                         fi->readdir_cache_idx = -1;
 449                         /* preclude from marking dir complete */
 450                         fi->dir_release_count = 0;
 451                 }
 452
 453                 /* note next offset and last dentry name */
 454                 if (rinfo->dir_nr > 0) {
 455                         struct ceph_mds_reply_dir_entry *rde =
 456                                         rinfo->dir_entries + (rinfo->dir_nr-1);
 457                         unsigned next_offset = req->r_reply_info.dir_end ?
 458                                         2 : (fpos_off(rde->offset) + 1);
 459                         err = note_last_dentry(fi, rde->name, rde->name_len,
 460                                                next_offset);
 461                         if (err)
 462                                 return err;
 463                 } else if (req->r_reply_info.dir_end) {
 464                         fi->next_offset = 2;
 465                         /* keep last name */
 466                 }
 467         }
 468
 469         rinfo = &fi->last_readdir->r_reply_info;
 470         dout("readdir frag %x num %d pos %llx chunk first %llx\n",
 471              fi->frag, rinfo->dir_nr, ctx->pos,
 472              rinfo->dir_nr ? rinfo->dir_entries[0].offset : 0LL);
 473
 474         i = 0;
 475         /* search start position */
 476         if (rinfo->dir_nr > 0) {
 477                 int step, nr = rinfo->dir_nr;
 478                 while (nr > 0) {
 479                         step = nr >> 1;
 480                         if (rinfo->dir_entries[i + step].offset < ctx->pos) {
 481                                 i +=  step + 1;
 482                                 nr -= step + 1;
 483                         } else {
 484                                 nr = step;
 485                         }
 486                 }
 487         }
 488         for (; i < rinfo->dir_nr; i++) {
 489                 struct ceph_mds_reply_dir_entry *rde = rinfo->dir_entries + i;
 490                 struct ceph_vino vino;
 491                 ino_t ino;
 492                 u32 ftype;
 493
 494                 BUG_ON(rde->offset < ctx->pos);
 495
 496                 ctx->pos = rde->offset;
 497                 dout("readdir (%d/%d) -> %llx '%.*s' %p\n",
 498                      i, rinfo->dir_nr, ctx->pos,
 499                      rde->name_len, rde->name, &rde->inode.in);
 500
 501                 BUG_ON(!rde->inode.in);
 502                 ftype = le32_to_cpu(rde->inode.in->mode) >> 12;
 503                 vino.ino = le64_to_cpu(rde->inode.in->ino);
 504                 vino.snap = le64_to_cpu(rde->inode.in->snapid);
 505                 ino = ceph_vino_to_ino(vino);
 506
 507                 if (!dir_emit(ctx, rde->name, rde->name_len,
 508                               ceph_translate_ino(inode->i_sb, ino), ftype)) {
 509                         dout("filldir stopping us...\n");
 510                         return 0;
 511                 }
 512                 ctx->pos++;
 513         }
 514
 515         ceph_mdsc_put_request(fi->last_readdir);
 516         fi->last_readdir = NULL;
 517
 518         if (fi->next_offset > 2) {
 519                 frag = fi->frag;
 520                 goto more;
 521         }
 522
 523         /* more frags? */
 524         if (!ceph_frag_is_rightmost(fi->frag)) {
 525                 frag = ceph_frag_next(fi->frag);
 526                 if (is_hash_order(ctx->pos)) {
 527                         loff_t new_pos = ceph_make_fpos(ceph_frag_value(frag),
 528                                                         fi->next_offset, true);
 529                         if (new_pos > ctx->pos)
 530                                 ctx->pos = new_pos;
 531                         /* keep last_name */
 532                 } else {
 533                         ctx->pos = ceph_make_fpos(frag, fi->next_offset, false);
 534                         kfree(fi->last_name);
 535                         fi->last_name = NULL;
 536                 }
 537                 dout("readdir next frag is %x\n", frag);
 538                 goto more;
 539         }
 540         fi->flags |= CEPH_F_ATEND;
 541
 542         /*
 543          * if dir_release_count still matches the dir, no dentries
 544          * were released during the whole readdir, and we should have
 545          * the complete dir contents in our cache.
 546          */
 547         if (atomic64_read(&ci->i_release_count) == fi->dir_release_count) {
 548                 spin_lock(&ci->i_ceph_lock);
 549                 if (fi->dir_ordered_count == atomic64_read(&ci->i_ordered_count)) {
 550                         dout(" marking %p complete and ordered\n", inode);
 551                         /* use i_size to track number of entries in
 552                          * readdir cache */
 553                         BUG_ON(fi->readdir_cache_idx < 0);
 554                         i_size_write(inode, fi->readdir_cache_idx *
 555                                      sizeof(struct dentry*));
 556                 } else {
 557                         dout(" marking %p complete\n", inode);
 558                 }
 559                 __ceph_dir_set_complete(ci, fi->dir_release_count,
 560                                         fi->dir_ordered_count);
 561                 spin_unlock(&ci->i_ceph_lock);
 562         }
 563
 564         dout("readdir %p file %p done.\n", inode, file);
 565         return 0;
 566 }
 567
 568 static void reset_readdir(struct ceph_file_info *fi)
 569 {
 570         if (fi->last_readdir) {
 571                 ceph_mdsc_put_request(fi->last_readdir);
 572                 fi->last_readdir = NULL;
 573         }
 574         kfree(fi->last_name);
 575         fi->last_name = NULL;
 576         fi->dir_release_count = 0;
 577         fi->readdir_cache_idx = -1;
 578         fi->next_offset = 2;  /* compensate for . and .. */
 579         fi->flags &= ~CEPH_F_ATEND;
 580 }
 581
 582 /*
 583  * discard buffered readdir content on seekdir(0), or seek to new frag,
 584  * or seek prior to current chunk
 585  */
 586 static bool need_reset_readdir(struct ceph_file_info *fi, loff_t new_pos)
 587 {
 588         struct ceph_mds_reply_info_parsed *rinfo;
 589         loff_t chunk_offset;
 590         if (new_pos == 0)
 591                 return true;
 592         if (is_hash_order(new_pos)) {
 593                 /* no need to reset last_name for a forward seek when
 594                  * dentries are sotred in hash order */
 595         } else if (fi->frag != fpos_frag(new_pos)) {
 596                 return true;
 597         }
 598         rinfo = fi->last_readdir ? &fi->last_readdir->r_reply_info : NULL;
 599         if (!rinfo || !rinfo->dir_nr)
 600                 return true;
 601         chunk_offset = rinfo->dir_entries[0].offset;
 602         return new_pos < chunk_offset ||
 603                is_hash_order(new_pos) != is_hash_order(chunk_offset);
 604 }
 605
 606 static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
 607 {
 608         struct ceph_file_info *fi = file->private_data;
 609         struct inode *inode = file->f_mapping->host;
 610         loff_t retval;
 611
 612         inode_lock(inode);
 613         retval = -EINVAL;
 614         switch (whence) {
 615         case SEEK_CUR:
 616                 offset += file->f_pos;
 617         case SEEK_SET:
 618                 break;
 619         case SEEK_END:
 620                 retval = -EOPNOTSUPP;
 621         default:
 622                 goto out;
 623         }
 624
 625         if (offset >= 0) {
 626                 if (need_reset_readdir(fi, offset)) {
 627                         dout("dir_llseek dropping %p content\n", file);
 628                         reset_readdir(fi);
 629                 } else if (is_hash_order(offset) && offset > file->f_pos) {
 630                         /* for hash offset, we don't know if a forward seek
 631                          * is within same frag */
 632                         fi->dir_release_count = 0;
 633                         fi->readdir_cache_idx = -1;
 634                 }
 635
 636                 if (offset != file->f_pos) {
 637                         file->f_pos = offset;
 638                         file->f_version = 0;
 639                         fi->flags &= ~CEPH_F_ATEND;
 640                 }
 641                 retval = offset;
 642         }
 643 out:
 644         inode_unlock(inode);
 645         return retval;
 646 }
 647
 648 /*
 649  * Handle lookups for the hidden .snap directory.
 650  */
 651 int ceph_handle_snapdir(struct ceph_mds_request *req,
 652                         struct dentry *dentry, int err)
 653 {
 654         struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
 655         struct inode *parent = d_inode(dentry->d_parent); /* we hold i_mutex */
 656
 657         /* .snap dir? */
 658         if (err == -ENOENT &&
 659             ceph_snap(parent) == CEPH_NOSNAP &&
 660             strcmp(dentry->d_name.name,
 661                    fsc->mount_options->snapdir_name) == 0) {
 662                 struct inode *inode = ceph_get_snapdir(parent);
 663                 dout("ENOENT on snapdir %p '%pd', linking to snapdir %p\n",
 664                      dentry, dentry, inode);
 665                 BUG_ON(!d_unhashed(dentry));
 666                 d_add(dentry, inode);
 667                 err = 0;
 668         }
 669         return err;
 670 }
 671
 672 /*
 673  * Figure out final result of a lookup/open request.
 674  *
 675  * Mainly, make sure we return the final req->r_dentry (if it already
 676  * existed) in place of the original VFS-provided dentry when they
 677  * differ.
 678  *
 679  * Gracefully handle the case where the MDS replies with -ENOENT and
 680  * no trace (which it may do, at its discretion, e.g., if it doesn't
 681  * care to issue a lease on the negative dentry).
 682  */
 683 struct dentry *ceph_finish_lookup(struct ceph_mds_request *req,
 684                                   struct dentry *dentry, int err)
 685 {
 686         if (err == -ENOENT) {
 687                 /* no trace? */
 688                 err = 0;
 689                 if (!req->r_reply_info.head->is_dentry) {
 690                         dout("ENOENT and no trace, dentry %p inode %p\n",
 691                              dentry, d_inode(dentry));
 692                         if (d_really_is_positive(dentry)) {
 693                                 d_drop(dentry);
 694                                 err = -ENOENT;
 695                         } else {
 696                                 d_add(dentry, NULL);
 697                         }
 698                 }
 699         }
 700         if (err)
 701                 dentry = ERR_PTR(err);
 702         else if (dentry != req->r_dentry)
 703                 dentry = dget(req->r_dentry);   /* we got spliced */
 704         else
 705                 dentry = NULL;
 706         return dentry;
 707 }
 708
 709 static bool is_root_ceph_dentry(struct inode *inode, struct dentry *dentry)
 710 {
 711         return ceph_ino(inode) == CEPH_INO_ROOT &&
 712                 strncmp(dentry->d_name.name, ".ceph", 5) == 0;
 713 }
 714
 715 /*
 716  * Look up a single dir entry.  If there is a lookup intent, inform
 717  * the MDS so that it gets our 'caps wanted' value in a single op.
 718  */
 719 static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
 720                                   unsigned int flags)
 721 {
 722         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
 723         struct ceph_mds_client *mdsc = fsc->mdsc;
 724         struct ceph_mds_request *req;
 725         int op;
 726         int mask;
 727         int err;
 728
 729         dout("lookup %p dentry %p '%pd'\n",
 730              dir, dentry, dentry);
 731
 732         if (dentry->d_name.len > NAME_MAX)
 733                 return ERR_PTR(-ENAMETOOLONG);
 734
 735         /* can we conclude ENOENT locally? */
 736         if (d_really_is_negative(dentry)) {
 737                 struct ceph_inode_info *ci = ceph_inode(dir);
 738                 struct ceph_dentry_info *di = ceph_dentry(dentry);
 739
 740                 spin_lock(&ci->i_ceph_lock);
 741                 dout(" dir %p flags are %d\n", dir, ci->i_ceph_flags);
 742                 if (strncmp(dentry->d_name.name,
 743                             fsc->mount_options->snapdir_name,
 744                             dentry->d_name.len) &&
 745                     !is_root_ceph_dentry(dir, dentry) &&
 746                     ceph_test_mount_opt(fsc, DCACHE) &&
 747                     __ceph_dir_is_complete(ci) &&
 748                     (__ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1))) {
 749                         spin_unlock(&ci->i_ceph_lock);
 750                         dout(" dir %p complete, -ENOENT\n", dir);
 751                         d_add(dentry, NULL);
 752                         di->lease_shared_gen = ci->i_shared_gen;
 753                         return NULL;
 754                 }
 755                 spin_unlock(&ci->i_ceph_lock);
 756         }
 757
 758         op = ceph_snap(dir) == CEPH_SNAPDIR ?
 759                 CEPH_MDS_OP_LOOKUPSNAP : CEPH_MDS_OP_LOOKUP;
 760         req = ceph_mdsc_create_request(mdsc, op, USE_ANY_MDS);
 761         if (IS_ERR(req))
 762                 return ERR_CAST(req);
 763         req->r_dentry = dget(dentry);
 764         req->r_num_caps = 2;
 765
 766         mask = CEPH_STAT_CAP_INODE | CEPH_CAP_AUTH_SHARED;
 767         if (ceph_security_xattr_wanted(dir))
 768                 mask |= CEPH_CAP_XATTR_SHARED;
 769         req->r_args.getattr.mask = cpu_to_le32(mask);
 770
 771         req->r_parent = dir;
 772         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
 773         err = ceph_mdsc_do_request(mdsc, NULL, req);
 774         err = ceph_handle_snapdir(req, dentry, err);
 775         dentry = ceph_finish_lookup(req, dentry, err);
 776         ceph_mdsc_put_request(req);  /* will dput(dentry) */
 777         dout("lookup result=%p\n", dentry);
 778         return dentry;
 779 }
 780
 781 /*
 782  * If we do a create but get no trace back from the MDS, follow up with
 783  * a lookup (the VFS expects us to link up the provided dentry).
 784  */
 785 int ceph_handle_notrace_create(struct inode *dir, struct dentry *dentry)
 786 {
 787         struct dentry *result = ceph_lookup(dir, dentry, 0);
 788
 789         if (result && !IS_ERR(result)) {
 790                 /*
 791                  * We created the item, then did a lookup, and found
 792                  * it was already linked to another inode we already
 793                  * had in our cache (and thus got spliced). To not
 794                  * confuse VFS (especially when inode is a directory),
 795                  * we don't link our dentry to that inode, return an
 796                  * error instead.
 797                  *
 798                  * This event should be rare and it happens only when
 799                  * we talk to old MDS. Recent MDS does not send traceless
 800                  * reply for request that creates new inode.
 801                  */
 802                 d_drop(result);
 803                 return -ESTALE;
 804         }
 805         return PTR_ERR(result);
 806 }
 807
 808 static int ceph_mknod(struct inode *dir, struct dentry *dentry,
 809                       umode_t mode, dev_t rdev)
 810 {
 811         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
 812         struct ceph_mds_client *mdsc = fsc->mdsc;
 813         struct ceph_mds_request *req;
 814         struct ceph_acls_info acls = {};
 815         int err;
 816
 817         if (ceph_snap(dir) != CEPH_NOSNAP)
 818                 return -EROFS;
 819
 820         err = ceph_pre_init_acls(dir, &mode, &acls);
 821         if (err < 0)
 822                 return err;
 823
 824         dout("mknod in dir %p dentry %p mode 0%ho rdev %d\n",
 825              dir, dentry, mode, rdev);
 826         req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_MKNOD, USE_AUTH_MDS);
 827         if (IS_ERR(req)) {
 828                 err = PTR_ERR(req);
 829                 goto out;
 830         }
 831         req->r_dentry = dget(dentry);
 832         req->r_num_caps = 2;
 833         req->r_parent = dir;
 834         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
 835         req->r_args.mknod.mode = cpu_to_le32(mode);
 836         req->r_args.mknod.rdev = cpu_to_le32(rdev);
 837         req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
 838         req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
 839         if (acls.pagelist) {
 840                 req->r_pagelist = acls.pagelist;
 841                 acls.pagelist = NULL;
 842         }
 843         err = ceph_mdsc_do_request(mdsc, dir, req);
 844         if (!err && !req->r_reply_info.head->is_dentry)
 845                 err = ceph_handle_notrace_create(dir, dentry);
 846         ceph_mdsc_put_request(req);
 847 out:
 848         if (!err)
 849                 ceph_init_inode_acls(d_inode(dentry), &acls);
 850         else
 851                 d_drop(dentry);
 852         ceph_release_acls_info(&acls);
 853         return err;
 854 }
 855
 856 static int ceph_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 857                        bool excl)
 858 {
 859         return ceph_mknod(dir, dentry, mode, 0);
 860 }
 861
 862 static int ceph_symlink(struct inode *dir, struct dentry *dentry,
 863                             const char *dest)
 864 {
 865         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
 866         struct ceph_mds_client *mdsc = fsc->mdsc;
 867         struct ceph_mds_request *req;
 868         int err;
 869
 870         if (ceph_snap(dir) != CEPH_NOSNAP)
 871                 return -EROFS;
 872
 873         dout("symlink in dir %p dentry %p to '%s'\n", dir, dentry, dest);
 874         req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SYMLINK, USE_AUTH_MDS);
 875         if (IS_ERR(req)) {
 876                 err = PTR_ERR(req);
 877                 goto out;
 878         }
 879         req->r_path2 = kstrdup(dest, GFP_KERNEL);
 880         if (!req->r_path2) {
 881                 err = -ENOMEM;
 882                 ceph_mdsc_put_request(req);
 883                 goto out;
 884         }
 885         req->r_parent = dir;
 886         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
 887         req->r_dentry = dget(dentry);
 888         req->r_num_caps = 2;
 889         req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
 890         req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
 891         err = ceph_mdsc_do_request(mdsc, dir, req);
 892         if (!err && !req->r_reply_info.head->is_dentry)
 893                 err = ceph_handle_notrace_create(dir, dentry);
 894         ceph_mdsc_put_request(req);
 895 out:
 896         if (err)
 897                 d_drop(dentry);
 898         return err;
 899 }
 900
 901 static int ceph_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 902 {
 903         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
 904         struct ceph_mds_client *mdsc = fsc->mdsc;
 905         struct ceph_mds_request *req;
 906         struct ceph_acls_info acls = {};
 907         int err = -EROFS;
 908         int op;
 909
 910         if (ceph_snap(dir) == CEPH_SNAPDIR) {
 911                 /* mkdir .snap/foo is a MKSNAP */
 912                 op = CEPH_MDS_OP_MKSNAP;
 913                 dout("mksnap dir %p snap '%pd' dn %p\n", dir,
 914                      dentry, dentry);
 915         } else if (ceph_snap(dir) == CEPH_NOSNAP) {
 916                 dout("mkdir dir %p dn %p mode 0%ho\n", dir, dentry, mode);
 917                 op = CEPH_MDS_OP_MKDIR;
 918         } else {
 919                 goto out;
 920         }
 921
 922         mode |= S_IFDIR;
 923         err = ceph_pre_init_acls(dir, &mode, &acls);
 924         if (err < 0)
 925                 goto out;
 926
 927         req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
 928         if (IS_ERR(req)) {
 929                 err = PTR_ERR(req);
 930                 goto out;
 931         }
 932
 933         req->r_dentry = dget(dentry);
 934         req->r_num_caps = 2;
 935         req->r_parent = dir;
 936         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
 937         req->r_args.mkdir.mode = cpu_to_le32(mode);
 938         req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
 939         req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
 940         if (acls.pagelist) {
 941                 req->r_pagelist = acls.pagelist;
 942                 acls.pagelist = NULL;
 943         }
 944         err = ceph_mdsc_do_request(mdsc, dir, req);
 945         if (!err &&
 946             !req->r_reply_info.head->is_target &&
 947             !req->r_reply_info.head->is_dentry)
 948                 err = ceph_handle_notrace_create(dir, dentry);
 949         ceph_mdsc_put_request(req);
 950 out:
 951         if (!err)
 952                 ceph_init_inode_acls(d_inode(dentry), &acls);
 953         else
 954                 d_drop(dentry);
 955         ceph_release_acls_info(&acls);
 956         return err;
 957 }
 958
 959 static int ceph_link(struct dentry *old_dentry, struct inode *dir,
 960                      struct dentry *dentry)
 961 {
 962         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
 963         struct ceph_mds_client *mdsc = fsc->mdsc;
 964         struct ceph_mds_request *req;
 965         int err;
 966
 967         if (ceph_snap(dir) != CEPH_NOSNAP)
 968                 return -EROFS;
 969
 970         dout("link in dir %p old_dentry %p dentry %p\n", dir,
 971              old_dentry, dentry);
 972         req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LINK, USE_AUTH_MDS);
 973         if (IS_ERR(req)) {
 974                 d_drop(dentry);
 975                 return PTR_ERR(req);
 976         }
 977         req->r_dentry = dget(dentry);
 978         req->r_num_caps = 2;
 979         req->r_old_dentry = dget(old_dentry);
 980         req->r_parent = dir;
 981         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
 982         req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
 983         req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
 984         /* release LINK_SHARED on source inode (mds will lock it) */
 985         req->r_old_inode_drop = CEPH_CAP_LINK_SHARED;
 986         err = ceph_mdsc_do_request(mdsc, dir, req);
 987         if (err) {
 988                 d_drop(dentry);
 989         } else if (!req->r_reply_info.head->is_dentry) {
 990                 ihold(d_inode(old_dentry));
 991                 d_instantiate(dentry, d_inode(old_dentry));
 992         }
 993         ceph_mdsc_put_request(req);
 994         return err;
 995 }
 996
 997 /*
 998  * For a soon-to-be unlinked file, drop the AUTH_RDCACHE caps.  If it
 999  * looks like the link count will hit 0, drop any other caps (other
1000  * than PIN) we don't specifically want (due to the file still being
1001  * open).
1002  */
1003 static int drop_caps_for_unlink(struct inode *inode)
1004 {
1005         struct ceph_inode_info *ci = ceph_inode(inode);
1006         int drop = CEPH_CAP_LINK_SHARED | CEPH_CAP_LINK_EXCL;
1007
1008         spin_lock(&ci->i_ceph_lock);
1009         if (inode->i_nlink == 1) {
1010                 drop |= ~(__ceph_caps_wanted(ci) | CEPH_CAP_PIN);
1011                 ci->i_ceph_flags |= CEPH_I_NODELAY;
1012         }
1013         spin_unlock(&ci->i_ceph_lock);
1014         return drop;
1015 }
1016
1017 /*
1018  * rmdir and unlink are differ only by the metadata op code
1019  */
1020 static int ceph_unlink(struct inode *dir, struct dentry *dentry)
1021 {
1022         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
1023         struct ceph_mds_client *mdsc = fsc->mdsc;
1024         struct inode *inode = d_inode(dentry);
1025         struct ceph_mds_request *req;
1026         int err = -EROFS;
1027         int op;
1028
1029         if (ceph_snap(dir) == CEPH_SNAPDIR) {
1030                 /* rmdir .snap/foo is RMSNAP */
1031                 dout("rmsnap dir %p '%pd' dn %p\n", dir, dentry, dentry);
1032                 op = CEPH_MDS_OP_RMSNAP;
1033         } else if (ceph_snap(dir) == CEPH_NOSNAP) {
1034                 dout("unlink/rmdir dir %p dn %p inode %p\n",
1035                      dir, dentry, inode);
1036                 op = d_is_dir(dentry) ?
1037                         CEPH_MDS_OP_RMDIR : CEPH_MDS_OP_UNLINK;
1038         } else
1039                 goto out;
1040         req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
1041         if (IS_ERR(req)) {
1042                 err = PTR_ERR(req);
1043                 goto out;
1044         }
1045         req->r_dentry = dget(dentry);
1046         req->r_num_caps = 2;
1047         req->r_parent = dir;
1048         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
1049         req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
1050         req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
1051         req->r_inode_drop = drop_caps_for_unlink(inode);
1052         err = ceph_mdsc_do_request(mdsc, dir, req);
1053         if (!err && !req->r_reply_info.head->is_dentry)
1054                 d_delete(dentry);
1055         ceph_mdsc_put_request(req);
1056 out:
1057         return err;
1058 }
1059
1060 static int ceph_rename(struct inode *old_dir, struct dentry *old_dentry,
1061                        struct inode *new_dir, struct dentry *new_dentry,
1062                        unsigned int flags)
1063 {
1064         struct ceph_fs_client *fsc = ceph_sb_to_client(old_dir->i_sb);
1065         struct ceph_mds_client *mdsc = fsc->mdsc;
1066         struct ceph_mds_request *req;
1067         int op = CEPH_MDS_OP_RENAME;
1068         int err;
1069
1070         if (flags)
1071                 return -EINVAL;
1072
1073         if (ceph_snap(old_dir) != ceph_snap(new_dir))
1074                 return -EXDEV;
1075         if (ceph_snap(old_dir) != CEPH_NOSNAP) {
1076                 if (old_dir == new_dir && ceph_snap(old_dir) == CEPH_SNAPDIR)
1077                         op = CEPH_MDS_OP_RENAMESNAP;
1078                 else
1079                         return -EROFS;
1080         }
1081         dout("rename dir %p dentry %p to dir %p dentry %p\n",
1082              old_dir, old_dentry, new_dir, new_dentry);
1083         req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
1084         if (IS_ERR(req))
1085                 return PTR_ERR(req);
1086         ihold(old_dir);
1087         req->r_dentry = dget(new_dentry);
1088         req->r_num_caps = 2;
1089         req->r_old_dentry = dget(old_dentry);
1090         req->r_old_dentry_dir = old_dir;
1091         req->r_parent = new_dir;
1092         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
1093         req->r_old_dentry_drop = CEPH_CAP_FILE_SHARED;
1094         req->r_old_dentry_unless = CEPH_CAP_FILE_EXCL;
1095         req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
1096         req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
1097         /* release LINK_RDCACHE on source inode (mds will lock it) */
1098         req->r_old_inode_drop = CEPH_CAP_LINK_SHARED;
1099         if (d_really_is_positive(new_dentry))
1100                 req->r_inode_drop = drop_caps_for_unlink(d_inode(new_dentry));
1101         err = ceph_mdsc_do_request(mdsc, old_dir, req);
1102         if (!err && !req->r_reply_info.head->is_dentry) {
1103                 /*
1104                  * Normally d_move() is done by fill_trace (called by
1105                  * do_request, above).  If there is no trace, we need
1106                  * to do it here.
1107                  */
1108
1109                 /* d_move screws up sibling dentries' offsets */
1110                 ceph_dir_clear_complete(old_dir);
1111                 ceph_dir_clear_complete(new_dir);
1112
1113                 d_move(old_dentry, new_dentry);
1114
1115                 /* ensure target dentry is invalidated, despite
1116                    rehashing bug in vfs_rename_dir */
1117                 ceph_invalidate_dentry_lease(new_dentry);
1118         }
1119         ceph_mdsc_put_request(req);
1120         return err;
1121 }
1122
1123 /*
1124  * Ensure a dentry lease will no longer revalidate.
1125  */
1126 void ceph_invalidate_dentry_lease(struct dentry *dentry)
1127 {
1128         spin_lock(&dentry->d_lock);
1129         ceph_dentry(dentry)->time = jiffies;
1130         ceph_dentry(dentry)->lease_shared_gen = 0;
1131         spin_unlock(&dentry->d_lock);
1132 }
1133
1134 /*
1135  * Check if dentry lease is valid.  If not, delete the lease.  Try to
1136  * renew if the least is more than half up.
1137  */
1138 static int dentry_lease_is_valid(struct dentry *dentry, unsigned int flags,
1139                                  struct inode *dir)
1140 {
1141         struct ceph_dentry_info *di;
1142         struct ceph_mds_session *s;
1143         int valid = 0;
1144         u32 gen;
1145         unsigned long ttl;
1146         struct ceph_mds_session *session = NULL;
1147         u32 seq = 0;
1148
1149         spin_lock(&dentry->d_lock);
1150         di = ceph_dentry(dentry);
1151         if (di && di->lease_session) {
1152                 s = di->lease_session;
1153                 spin_lock(&s->s_gen_ttl_lock);
1154                 gen = s->s_cap_gen;
1155                 ttl = s->s_cap_ttl;
1156                 spin_unlock(&s->s_gen_ttl_lock);
1157
1158                 if (di->lease_gen == gen &&
1159                     time_before(jiffies, di->time) &&
1160                     time_before(jiffies, ttl)) {
1161                         valid = 1;
1162                         if (di->lease_renew_after &&
1163                             time_after(jiffies, di->lease_renew_after)) {
1164                                 /*
1165                                  * We should renew. If we're in RCU walk mode
1166                                  * though, we can't do that so just return
1167                                  * -ECHILD.
1168                                  */
1169                                 if (flags & LOOKUP_RCU) {
1170                                         valid = -ECHILD;
1171                                 } else {
1172                                         session = ceph_get_mds_session(s);
1173                                         seq = di->lease_seq;
1174                                         di->lease_renew_after = 0;
1175                                         di->lease_renew_from = jiffies;
1176                                 }
1177                         }
1178                 }
1179         }
1180         spin_unlock(&dentry->d_lock);
1181
1182         if (session) {
1183                 ceph_mdsc_lease_send_msg(session, dir, dentry,
1184                                          CEPH_MDS_LEASE_RENEW, seq);
1185                 ceph_put_mds_session(session);
1186         }
1187         dout("dentry_lease_is_valid - dentry %p = %d\n", dentry, valid);
1188         return valid;
1189 }
1190
1191 /*
1192  * Check if directory-wide content lease/cap is valid.
1193  */
1194 static int dir_lease_is_valid(struct inode *dir, struct dentry *dentry)
1195 {
1196         struct ceph_inode_info *ci = ceph_inode(dir);
1197         struct ceph_dentry_info *di = ceph_dentry(dentry);
1198         int valid = 0;
1199
1200         spin_lock(&ci->i_ceph_lock);
1201         if (ci->i_shared_gen == di->lease_shared_gen)
1202                 valid = __ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1);
1203         spin_unlock(&ci->i_ceph_lock);
1204         dout("dir_lease_is_valid dir %p v%u dentry %p v%u = %d\n",
1205              dir, (unsigned)ci->i_shared_gen, dentry,
1206              (unsigned)di->lease_shared_gen, valid);
1207         return valid;
1208 }
1209
1210 /*
1211  * Check if cached dentry can be trusted.
1212  */
1213 static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
1214 {
1215         int valid = 0;
1216         struct dentry *parent;
1217         struct inode *dir;
1218
1219         if (flags & LOOKUP_RCU) {
1220                 parent = READ_ONCE(dentry->d_parent);
1221                 dir = d_inode_rcu(parent);
1222                 if (!dir)
1223                         return -ECHILD;
1224         } else {
1225                 parent = dget_parent(dentry);
1226                 dir = d_inode(parent);
1227         }
1228
1229         dout("d_revalidate %p '%pd' inode %p offset %lld\n", dentry,
1230              dentry, d_inode(dentry), ceph_dentry(dentry)->offset);
1231
1232         /* always trust cached snapped dentries, snapdir dentry */
1233         if (ceph_snap(dir) != CEPH_NOSNAP) {
1234                 dout("d_revalidate %p '%pd' inode %p is SNAPPED\n", dentry,
1235                      dentry, d_inode(dentry));
1236                 valid = 1;
1237         } else if (d_really_is_positive(dentry) &&
1238                    ceph_snap(d_inode(dentry)) == CEPH_SNAPDIR) {
1239                 valid = 1;
1240         } else {
1241                 valid = dentry_lease_is_valid(dentry, flags, dir);
1242                 if (valid == -ECHILD)
1243                         return valid;
1244                 if (valid || dir_lease_is_valid(dir, dentry)) {
1245                         if (d_really_is_positive(dentry))
1246                                 valid = ceph_is_any_caps(d_inode(dentry));
1247                         else
1248                                 valid = 1;
1249                 }
1250         }
1251
1252         if (!valid) {
1253                 struct ceph_mds_client *mdsc =
1254                         ceph_sb_to_client(dir->i_sb)->mdsc;
1255                 struct ceph_mds_request *req;
1256                 int op, err;
1257                 u32 mask;
1258
1259                 if (flags & LOOKUP_RCU)
1260                         return -ECHILD;
1261
1262                 op = ceph_snap(dir) == CEPH_SNAPDIR ?
1263                         CEPH_MDS_OP_LOOKUPSNAP : CEPH_MDS_OP_LOOKUP;
1264                 req = ceph_mdsc_create_request(mdsc, op, USE_ANY_MDS);
1265                 if (!IS_ERR(req)) {
1266                         req->r_dentry = dget(dentry);
1267                         req->r_num_caps = 2;
1268                         req->r_parent = dir;
1269
1270                         mask = CEPH_STAT_CAP_INODE | CEPH_CAP_AUTH_SHARED;
1271                         if (ceph_security_xattr_wanted(dir))
1272                                 mask |= CEPH_CAP_XATTR_SHARED;
1273                         req->r_args.getattr.mask = cpu_to_le32(mask);
1274
1275                         err = ceph_mdsc_do_request(mdsc, NULL, req);
1276                         switch (err) {
1277                         case 0:
1278                                 if (d_really_is_positive(dentry) &&
1279                                     d_inode(dentry) == req->r_target_inode)
1280                                         valid = 1;
1281                                 break;
1282                         case -ENOENT:
1283                                 if (d_really_is_negative(dentry))
1284                                         valid = 1;
1285                                 /* Fallthrough */
1286                         default:
1287                                 break;
1288                         }
1289                         ceph_mdsc_put_request(req);
1290                         dout("d_revalidate %p lookup result=%d\n",
1291                              dentry, err);
1292                 }
1293         }
1294
1295         dout("d_revalidate %p %s\n", dentry, valid ? "valid" : "invalid");
1296         if (valid) {
1297                 ceph_dentry_lru_touch(dentry);
1298         } else {
1299                 ceph_dir_clear_complete(dir);
1300         }
1301
1302         if (!(flags & LOOKUP_RCU))
1303                 dput(parent);
1304         return valid;
1305 }
1306
1307 /*
1308  * Release our ceph_dentry_info.
1309  */
1310 static void ceph_d_release(struct dentry *dentry)
1311 {
1312         struct ceph_dentry_info *di = ceph_dentry(dentry);
1313
1314         dout("d_release %p\n", dentry);
1315         ceph_dentry_lru_del(dentry);
1316
1317         spin_lock(&dentry->d_lock);
1318         dentry->d_fsdata = NULL;
1319         spin_unlock(&dentry->d_lock);
1320
1321         if (di->lease_session)
1322                 ceph_put_mds_session(di->lease_session);
1323         kmem_cache_free(ceph_dentry_cachep, di);
1324 }
1325
1326 /*
1327  * When the VFS prunes a dentry from the cache, we need to clear the
1328  * complete flag on the parent directory.
1329  *
1330  * Called under dentry->d_lock.
1331  */
1332 static void ceph_d_prune(struct dentry *dentry)
1333 {
1334         dout("ceph_d_prune %p\n", dentry);
1335
1336         /* do we have a valid parent? */
1337         if (IS_ROOT(dentry))
1338                 return;
1339
1340         /* if we are not hashed, we don't affect dir's completeness */
1341         if (d_unhashed(dentry))
1342                 return;
1343
1344         if (ceph_snap(d_inode(dentry->d_parent)) == CEPH_SNAPDIR)
1345                 return;
1346
1347         /*
1348          * we hold d_lock, so d_parent is stable, and d_fsdata is never
1349          * cleared until d_release
1350          */
1351         ceph_dir_clear_complete(d_inode(dentry->d_parent));
1352 }
1353
1354 /*
1355  * read() on a dir.  This weird interface hack only works if mounted
1356  * with '-o dirstat'.
1357  */
1358 static ssize_t ceph_read_dir(struct file *file, char __user *buf, size_t size,
1359                              loff_t *ppos)
1360 {
1361         struct ceph_file_info *cf = file->private_data;
1362         struct inode *inode = file_inode(file);
1363         struct ceph_inode_info *ci = ceph_inode(inode);
1364         int left;
1365         const int bufsize = 1024;
1366
1367         if (!ceph_test_mount_opt(ceph_sb_to_client(inode->i_sb), DIRSTAT))
1368                 return -EISDIR;
1369
1370         if (!cf->dir_info) {
1371                 cf->dir_info = kmalloc(bufsize, GFP_KERNEL);
1372                 if (!cf->dir_info)
1373                         return -ENOMEM;
1374                 cf->dir_info_len =
1375                         snprintf(cf->dir_info, bufsize,
1376                                 "entries:   %20lld\n"
1377                                 " files:    %20lld\n"
1378                                 " subdirs:  %20lld\n"
1379                                 "rentries:  %20lld\n"
1380                                 " rfiles:   %20lld\n"
1381                                 " rsubdirs: %20lld\n"
1382                                 "rbytes:    %20lld\n"
1383                                 "rctime:    %10ld.%09ld\n",
1384                                 ci->i_files + ci->i_subdirs,
1385                                 ci->i_files,
1386                                 ci->i_subdirs,
1387                                 ci->i_rfiles + ci->i_rsubdirs,
1388                                 ci->i_rfiles,
1389                                 ci->i_rsubdirs,
1390                                 ci->i_rbytes,
1391                                 (long)ci->i_rctime.tv_sec,
1392                                 (long)ci->i_rctime.tv_nsec);
1393         }
1394
1395         if (*ppos >= cf->dir_info_len)
1396                 return 0;
1397         size = min_t(unsigned, size, cf->dir_info_len-*ppos);
1398         left = copy_to_user(buf, cf->dir_info + *ppos, size);
1399         if (left == size)
1400                 return -EFAULT;
1401         *ppos += (size - left);
1402         return size - left;
1403 }
1404
1405 /*
1406  * We maintain a private dentry LRU.
1407  *
1408  * FIXME: this needs to be changed to a per-mds lru to be useful.
1409  */
1410 void ceph_dentry_lru_add(struct dentry *dn)
1411 {
1412         struct ceph_dentry_info *di = ceph_dentry(dn);
1413         struct ceph_mds_client *mdsc;
1414
1415         dout("dentry_lru_add %p %p '%pd'\n", di, dn, dn);
1416         mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
1417         spin_lock(&mdsc->dentry_lru_lock);
1418         list_add_tail(&di->lru, &mdsc->dentry_lru);
1419         mdsc->num_dentry++;
1420         spin_unlock(&mdsc->dentry_lru_lock);
1421 }
1422
1423 void ceph_dentry_lru_touch(struct dentry *dn)
1424 {
1425         struct ceph_dentry_info *di = ceph_dentry(dn);
1426         struct ceph_mds_client *mdsc;
1427
1428         dout("dentry_lru_touch %p %p '%pd' (offset %lld)\n", di, dn, dn,
1429              di->offset);
1430         mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
1431         spin_lock(&mdsc->dentry_lru_lock);
1432         list_move_tail(&di->lru, &mdsc->dentry_lru);
1433         spin_unlock(&mdsc->dentry_lru_lock);
1434 }
1435
1436 void ceph_dentry_lru_del(struct dentry *dn)
1437 {
1438         struct ceph_dentry_info *di = ceph_dentry(dn);
1439         struct ceph_mds_client *mdsc;
1440
1441         dout("dentry_lru_del %p %p '%pd'\n", di, dn, dn);
1442         mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
1443         spin_lock(&mdsc->dentry_lru_lock);
1444         list_del_init(&di->lru);
1445         mdsc->num_dentry--;
1446         spin_unlock(&mdsc->dentry_lru_lock);
1447 }
1448
1449 /*
1450  * Return name hash for a given dentry.  This is dependent on
1451  * the parent directory's hash function.
1452  */
1453 unsigned ceph_dentry_hash(struct inode *dir, struct dentry *dn)
1454 {
1455         struct ceph_inode_info *dci = ceph_inode(dir);
1456
1457         switch (dci->i_dir_layout.dl_dir_hash) {
1458         case 0: /* for backward compat */
1459         case CEPH_STR_HASH_LINUX:
1460                 return dn->d_name.hash;
1461
1462         default:
1463                 return ceph_str_hash(dci->i_dir_layout.dl_dir_hash,
1464                                      dn->d_name.name, dn->d_name.len);
1465         }
1466 }
1467
1468 const struct file_operations ceph_dir_fops = {
1469         .read = ceph_read_dir,
1470         .iterate = ceph_readdir,
1471         .llseek = ceph_dir_llseek,
1472         .open = ceph_open,
1473         .release = ceph_release,
1474         .unlocked_ioctl = ceph_ioctl,
1475         .fsync = ceph_fsync,
1476 };
1477
1478 const struct file_operations ceph_snapdir_fops = {
1479         .iterate = ceph_readdir,
1480         .llseek = ceph_dir_llseek,
1481         .open = ceph_open,
1482         .release = ceph_release,
1483 };
1484
1485 const struct inode_operations ceph_dir_iops = {
1486         .lookup = ceph_lookup,
1487         .permission = ceph_permission,
1488         .getattr = ceph_getattr,
1489         .setattr = ceph_setattr,
1490         .listxattr = ceph_listxattr,
1491         .get_acl = ceph_get_acl,
1492         .set_acl = ceph_set_acl,
1493         .mknod = ceph_mknod,
1494         .symlink = ceph_symlink,
1495         .mkdir = ceph_mkdir,
1496         .link = ceph_link,
1497         .unlink = ceph_unlink,
1498         .rmdir = ceph_unlink,
1499         .rename = ceph_rename,
1500         .create = ceph_create,
1501         .atomic_open = ceph_atomic_open,
1502 };
1503
1504 const struct inode_operations ceph_snapdir_iops = {
1505         .lookup = ceph_lookup,
1506         .permission = ceph_permission,
1507         .getattr = ceph_getattr,
1508         .mkdir = ceph_mkdir,
1509         .rmdir = ceph_unlink,
1510         .rename = ceph_rename,
1511 };
1512
1513 const struct dentry_operations ceph_dentry_ops = {
1514         .d_revalidate = ceph_d_revalidate,
1515         .d_release = ceph_d_release,
1516         .d_prune = ceph_d_prune,
1517         .d_init = ceph_d_init,
1518 };