fs/ceph/dir.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/ceph/ceph_debug.h>
   3
   4 #include <linux/spinlock.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                             int 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, (unsigned)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                 spin_lock(&dentry->d_lock);
 234                 di = ceph_dentry(dentry);
 235                 if (d_unhashed(dentry) ||
 236                     d_really_is_negative(dentry) ||
 237                     di->lease_shared_gen != shared_gen) {
 238                         spin_unlock(&dentry->d_lock);
 239                         dput(dentry);
 240                         err = -EAGAIN;
 241                         goto out;
 242                 }
 243                 if (fpos_cmp(ctx->pos, di->offset) <= 0) {
 244                         emit_dentry = true;
 245                 }
 246                 spin_unlock(&dentry->d_lock);
 247
 248                 if (emit_dentry) {
 249                         dout(" %llx dentry %p %pd %p\n", di->offset,
 250                              dentry, dentry, d_inode(dentry));
 251                         ctx->pos = di->offset;
 252                         if (!dir_emit(ctx, dentry->d_name.name,
 253                                       dentry->d_name.len,
 254                                       ceph_translate_ino(dentry->d_sb,
 255                                                          d_inode(dentry)->i_ino),
 256                                       d_inode(dentry)->i_mode >> 12)) {
 257                                 dput(dentry);
 258                                 err = 0;
 259                                 break;
 260                         }
 261                         ctx->pos++;
 262
 263                         if (last)
 264                                 dput(last);
 265                         last = dentry;
 266                 } else {
 267                         dput(dentry);
 268                 }
 269         }
 270 out:
 271         ceph_readdir_cache_release(&cache_ctl);
 272         if (last) {
 273                 int ret;
 274                 di = ceph_dentry(last);
 275                 ret = note_last_dentry(fi, last->d_name.name, last->d_name.len,
 276                                        fpos_off(di->offset) + 1);
 277                 if (ret < 0)
 278                         err = ret;
 279                 dput(last);
 280                 /* last_name no longer match cache index */
 281                 if (fi->readdir_cache_idx >= 0) {
 282                         fi->readdir_cache_idx = -1;
 283                         fi->dir_release_count = 0;
 284                 }
 285         }
 286         return err;
 287 }
 288
 289 static bool need_send_readdir(struct ceph_file_info *fi, loff_t pos)
 290 {
 291         if (!fi->last_readdir)
 292                 return true;
 293         if (is_hash_order(pos))
 294                 return !ceph_frag_contains_value(fi->frag, fpos_hash(pos));
 295         else
 296                 return fi->frag != fpos_frag(pos);
 297 }
 298
 299 static int ceph_readdir(struct file *file, struct dir_context *ctx)
 300 {
 301         struct ceph_file_info *fi = file->private_data;
 302         struct inode *inode = file_inode(file);
 303         struct ceph_inode_info *ci = ceph_inode(inode);
 304         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 305         struct ceph_mds_client *mdsc = fsc->mdsc;
 306         int i;
 307         int err;
 308         unsigned frag = -1;
 309         struct ceph_mds_reply_info_parsed *rinfo;
 310
 311         dout("readdir %p file %p pos %llx\n", inode, file, ctx->pos);
 312         if (fi->flags & CEPH_F_ATEND)
 313                 return 0;
 314
 315         /* always start with . and .. */
 316         if (ctx->pos == 0) {
 317                 dout("readdir off 0 -> '.'\n");
 318                 if (!dir_emit(ctx, ".", 1,
 319                             ceph_translate_ino(inode->i_sb, inode->i_ino),
 320                             inode->i_mode >> 12))
 321                         return 0;
 322                 ctx->pos = 1;
 323         }
 324         if (ctx->pos == 1) {
 325                 ino_t ino = parent_ino(file->f_path.dentry);
 326                 dout("readdir off 1 -> '..'\n");
 327                 if (!dir_emit(ctx, "..", 2,
 328                             ceph_translate_ino(inode->i_sb, ino),
 329                             inode->i_mode >> 12))
 330                         return 0;
 331                 ctx->pos = 2;
 332         }
 333
 334         /* can we use the dcache? */
 335         spin_lock(&ci->i_ceph_lock);
 336         if (ceph_test_mount_opt(fsc, DCACHE) &&
 337             !ceph_test_mount_opt(fsc, NOASYNCREADDIR) &&
 338             ceph_snap(inode) != CEPH_SNAPDIR &&
 339             __ceph_dir_is_complete_ordered(ci) &&
 340             __ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1)) {
 341                 int shared_gen = atomic_read(&ci->i_shared_gen);
 342                 spin_unlock(&ci->i_ceph_lock);
 343                 err = __dcache_readdir(file, ctx, shared_gen);
 344                 if (err != -EAGAIN)
 345                         return err;
 346         } else {
 347                 spin_unlock(&ci->i_ceph_lock);
 348         }
 349
 350         /* proceed with a normal readdir */
 351 more:
 352         /* do we have the correct frag content buffered? */
 353         if (need_send_readdir(fi, ctx->pos)) {
 354                 struct ceph_mds_request *req;
 355                 int op = ceph_snap(inode) == CEPH_SNAPDIR ?
 356                         CEPH_MDS_OP_LSSNAP : CEPH_MDS_OP_READDIR;
 357
 358                 /* discard old result, if any */
 359                 if (fi->last_readdir) {
 360                         ceph_mdsc_put_request(fi->last_readdir);
 361                         fi->last_readdir = NULL;
 362                 }
 363
 364                 if (is_hash_order(ctx->pos)) {
 365                         /* fragtree isn't always accurate. choose frag
 366                          * based on previous reply when possible. */
 367                         if (frag == (unsigned)-1)
 368                                 frag = ceph_choose_frag(ci, fpos_hash(ctx->pos),
 369                                                         NULL, NULL);
 370                 } else {
 371                         frag = fpos_frag(ctx->pos);
 372                 }
 373
 374                 dout("readdir fetching %llx.%llx frag %x offset '%s'\n",
 375                      ceph_vinop(inode), frag, fi->last_name);
 376                 req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
 377                 if (IS_ERR(req))
 378                         return PTR_ERR(req);
 379                 err = ceph_alloc_readdir_reply_buffer(req, inode);
 380                 if (err) {
 381                         ceph_mdsc_put_request(req);
 382                         return err;
 383                 }
 384                 /* hints to request -> mds selection code */
 385                 req->r_direct_mode = USE_AUTH_MDS;
 386                 if (op == CEPH_MDS_OP_READDIR) {
 387                         req->r_direct_hash = ceph_frag_value(frag);
 388                         __set_bit(CEPH_MDS_R_DIRECT_IS_HASH, &req->r_req_flags);
 389                         req->r_inode_drop = CEPH_CAP_FILE_EXCL;
 390                 }
 391                 if (fi->last_name) {
 392                         req->r_path2 = kstrdup(fi->last_name, GFP_KERNEL);
 393                         if (!req->r_path2) {
 394                                 ceph_mdsc_put_request(req);
 395                                 return -ENOMEM;
 396                         }
 397                 } else if (is_hash_order(ctx->pos)) {
 398                         req->r_args.readdir.offset_hash =
 399                                 cpu_to_le32(fpos_hash(ctx->pos));
 400                 }
 401
 402                 req->r_dir_release_cnt = fi->dir_release_count;
 403                 req->r_dir_ordered_cnt = fi->dir_ordered_count;
 404                 req->r_readdir_cache_idx = fi->readdir_cache_idx;
 405                 req->r_readdir_offset = fi->next_offset;
 406                 req->r_args.readdir.frag = cpu_to_le32(frag);
 407                 req->r_args.readdir.flags =
 408                                 cpu_to_le16(CEPH_READDIR_REPLY_BITFLAGS);
 409
 410                 req->r_inode = inode;
 411                 ihold(inode);
 412                 req->r_dentry = dget(file->f_path.dentry);
 413                 err = ceph_mdsc_do_request(mdsc, NULL, req);
 414                 if (err < 0) {
 415                         ceph_mdsc_put_request(req);
 416                         return err;
 417                 }
 418                 dout("readdir got and parsed readdir result=%d on "
 419                      "frag %x, end=%d, complete=%d, hash_order=%d\n",
 420                      err, frag,
 421                      (int)req->r_reply_info.dir_end,
 422                      (int)req->r_reply_info.dir_complete,
 423                      (int)req->r_reply_info.hash_order);
 424
 425                 rinfo = &req->r_reply_info;
 426                 if (le32_to_cpu(rinfo->dir_dir->frag) != frag) {
 427                         frag = le32_to_cpu(rinfo->dir_dir->frag);
 428                         if (!rinfo->hash_order) {
 429                                 fi->next_offset = req->r_readdir_offset;
 430                                 /* adjust ctx->pos to beginning of frag */
 431                                 ctx->pos = ceph_make_fpos(frag,
 432                                                           fi->next_offset,
 433                                                           false);
 434                         }
 435                 }
 436
 437                 fi->frag = frag;
 438                 fi->last_readdir = req;
 439
 440                 if (test_bit(CEPH_MDS_R_DID_PREPOPULATE, &req->r_req_flags)) {
 441                         fi->readdir_cache_idx = req->r_readdir_cache_idx;
 442                         if (fi->readdir_cache_idx < 0) {
 443                                 /* preclude from marking dir ordered */
 444                                 fi->dir_ordered_count = 0;
 445                         } else if (ceph_frag_is_leftmost(frag) &&
 446                                    fi->next_offset == 2) {
 447                                 /* note dir version at start of readdir so
 448                                  * we can tell if any dentries get dropped */
 449                                 fi->dir_release_count = req->r_dir_release_cnt;
 450                                 fi->dir_ordered_count = req->r_dir_ordered_cnt;
 451                         }
 452                 } else {
 453                         dout("readdir !did_prepopulate");
 454                         /* disable readdir cache */
 455                         fi->readdir_cache_idx = -1;
 456                         /* preclude from marking dir complete */
 457                         fi->dir_release_count = 0;
 458                 }
 459
 460                 /* note next offset and last dentry name */
 461                 if (rinfo->dir_nr > 0) {
 462                         struct ceph_mds_reply_dir_entry *rde =
 463                                         rinfo->dir_entries + (rinfo->dir_nr-1);
 464                         unsigned next_offset = req->r_reply_info.dir_end ?
 465                                         2 : (fpos_off(rde->offset) + 1);
 466                         err = note_last_dentry(fi, rde->name, rde->name_len,
 467                                                next_offset);
 468                         if (err)
 469                                 return err;
 470                 } else if (req->r_reply_info.dir_end) {
 471                         fi->next_offset = 2;
 472                         /* keep last name */
 473                 }
 474         }
 475
 476         rinfo = &fi->last_readdir->r_reply_info;
 477         dout("readdir frag %x num %d pos %llx chunk first %llx\n",
 478              fi->frag, rinfo->dir_nr, ctx->pos,
 479              rinfo->dir_nr ? rinfo->dir_entries[0].offset : 0LL);
 480
 481         i = 0;
 482         /* search start position */
 483         if (rinfo->dir_nr > 0) {
 484                 int step, nr = rinfo->dir_nr;
 485                 while (nr > 0) {
 486                         step = nr >> 1;
 487                         if (rinfo->dir_entries[i + step].offset < ctx->pos) {
 488                                 i +=  step + 1;
 489                                 nr -= step + 1;
 490                         } else {
 491                                 nr = step;
 492                         }
 493                 }
 494         }
 495         for (; i < rinfo->dir_nr; i++) {
 496                 struct ceph_mds_reply_dir_entry *rde = rinfo->dir_entries + i;
 497                 struct ceph_vino vino;
 498                 ino_t ino;
 499                 u32 ftype;
 500
 501                 BUG_ON(rde->offset < ctx->pos);
 502
 503                 ctx->pos = rde->offset;
 504                 dout("readdir (%d/%d) -> %llx '%.*s' %p\n",
 505                      i, rinfo->dir_nr, ctx->pos,
 506                      rde->name_len, rde->name, &rde->inode.in);
 507
 508                 BUG_ON(!rde->inode.in);
 509                 ftype = le32_to_cpu(rde->inode.in->mode) >> 12;
 510                 vino.ino = le64_to_cpu(rde->inode.in->ino);
 511                 vino.snap = le64_to_cpu(rde->inode.in->snapid);
 512                 ino = ceph_vino_to_ino(vino);
 513
 514                 if (!dir_emit(ctx, rde->name, rde->name_len,
 515                               ceph_translate_ino(inode->i_sb, ino), ftype)) {
 516                         dout("filldir stopping us...\n");
 517                         return 0;
 518                 }
 519                 ctx->pos++;
 520         }
 521
 522         ceph_mdsc_put_request(fi->last_readdir);
 523         fi->last_readdir = NULL;
 524
 525         if (fi->next_offset > 2) {
 526                 frag = fi->frag;
 527                 goto more;
 528         }
 529
 530         /* more frags? */
 531         if (!ceph_frag_is_rightmost(fi->frag)) {
 532                 frag = ceph_frag_next(fi->frag);
 533                 if (is_hash_order(ctx->pos)) {
 534                         loff_t new_pos = ceph_make_fpos(ceph_frag_value(frag),
 535                                                         fi->next_offset, true);
 536                         if (new_pos > ctx->pos)
 537                                 ctx->pos = new_pos;
 538                         /* keep last_name */
 539                 } else {
 540                         ctx->pos = ceph_make_fpos(frag, fi->next_offset, false);
 541                         kfree(fi->last_name);
 542                         fi->last_name = NULL;
 543                 }
 544                 dout("readdir next frag is %x\n", frag);
 545                 goto more;
 546         }
 547         fi->flags |= CEPH_F_ATEND;
 548
 549         /*
 550          * if dir_release_count still matches the dir, no dentries
 551          * were released during the whole readdir, and we should have
 552          * the complete dir contents in our cache.
 553          */
 554         if (atomic64_read(&ci->i_release_count) == fi->dir_release_count) {
 555                 spin_lock(&ci->i_ceph_lock);
 556                 if (fi->dir_ordered_count == atomic64_read(&ci->i_ordered_count)) {
 557                         dout(" marking %p complete and ordered\n", inode);
 558                         /* use i_size to track number of entries in
 559                          * readdir cache */
 560                         BUG_ON(fi->readdir_cache_idx < 0);
 561                         i_size_write(inode, fi->readdir_cache_idx *
 562                                      sizeof(struct dentry*));
 563                 } else {
 564                         dout(" marking %p complete\n", inode);
 565                 }
 566                 __ceph_dir_set_complete(ci, fi->dir_release_count,
 567                                         fi->dir_ordered_count);
 568                 spin_unlock(&ci->i_ceph_lock);
 569         }
 570
 571         dout("readdir %p file %p done.\n", inode, file);
 572         return 0;
 573 }
 574
 575 static void reset_readdir(struct ceph_file_info *fi)
 576 {
 577         if (fi->last_readdir) {
 578                 ceph_mdsc_put_request(fi->last_readdir);
 579                 fi->last_readdir = NULL;
 580         }
 581         kfree(fi->last_name);
 582         fi->last_name = NULL;
 583         fi->dir_release_count = 0;
 584         fi->readdir_cache_idx = -1;
 585         fi->next_offset = 2;  /* compensate for . and .. */
 586         fi->flags &= ~CEPH_F_ATEND;
 587 }
 588
 589 /*
 590  * discard buffered readdir content on seekdir(0), or seek to new frag,
 591  * or seek prior to current chunk
 592  */
 593 static bool need_reset_readdir(struct ceph_file_info *fi, loff_t new_pos)
 594 {
 595         struct ceph_mds_reply_info_parsed *rinfo;
 596         loff_t chunk_offset;
 597         if (new_pos == 0)
 598                 return true;
 599         if (is_hash_order(new_pos)) {
 600                 /* no need to reset last_name for a forward seek when
 601                  * dentries are sotred in hash order */
 602         } else if (fi->frag != fpos_frag(new_pos)) {
 603                 return true;
 604         }
 605         rinfo = fi->last_readdir ? &fi->last_readdir->r_reply_info : NULL;
 606         if (!rinfo || !rinfo->dir_nr)
 607                 return true;
 608         chunk_offset = rinfo->dir_entries[0].offset;
 609         return new_pos < chunk_offset ||
 610                is_hash_order(new_pos) != is_hash_order(chunk_offset);
 611 }
 612
 613 static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
 614 {
 615         struct ceph_file_info *fi = file->private_data;
 616         struct inode *inode = file->f_mapping->host;
 617         loff_t retval;
 618
 619         inode_lock(inode);
 620         retval = -EINVAL;
 621         switch (whence) {
 622         case SEEK_CUR:
 623                 offset += file->f_pos;
 624         case SEEK_SET:
 625                 break;
 626         case SEEK_END:
 627                 retval = -EOPNOTSUPP;
 628         default:
 629                 goto out;
 630         }
 631
 632         if (offset >= 0) {
 633                 if (need_reset_readdir(fi, offset)) {
 634                         dout("dir_llseek dropping %p content\n", file);
 635                         reset_readdir(fi);
 636                 } else if (is_hash_order(offset) && offset > file->f_pos) {
 637                         /* for hash offset, we don't know if a forward seek
 638                          * is within same frag */
 639                         fi->dir_release_count = 0;
 640                         fi->readdir_cache_idx = -1;
 641                 }
 642
 643                 if (offset != file->f_pos) {
 644                         file->f_pos = offset;
 645                         file->f_version = 0;
 646                         fi->flags &= ~CEPH_F_ATEND;
 647                 }
 648                 retval = offset;
 649         }
 650 out:
 651         inode_unlock(inode);
 652         return retval;
 653 }
 654
 655 /*
 656  * Handle lookups for the hidden .snap directory.
 657  */
 658 int ceph_handle_snapdir(struct ceph_mds_request *req,
 659                         struct dentry *dentry, int err)
 660 {
 661         struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
 662         struct inode *parent = d_inode(dentry->d_parent); /* we hold i_mutex */
 663
 664         /* .snap dir? */
 665         if (err == -ENOENT &&
 666             ceph_snap(parent) == CEPH_NOSNAP &&
 667             strcmp(dentry->d_name.name,
 668                    fsc->mount_options->snapdir_name) == 0) {
 669                 struct inode *inode = ceph_get_snapdir(parent);
 670                 dout("ENOENT on snapdir %p '%pd', linking to snapdir %p\n",
 671                      dentry, dentry, inode);
 672                 BUG_ON(!d_unhashed(dentry));
 673                 d_add(dentry, inode);
 674                 err = 0;
 675         }
 676         return err;
 677 }
 678
 679 /*
 680  * Figure out final result of a lookup/open request.
 681  *
 682  * Mainly, make sure we return the final req->r_dentry (if it already
 683  * existed) in place of the original VFS-provided dentry when they
 684  * differ.
 685  *
 686  * Gracefully handle the case where the MDS replies with -ENOENT and
 687  * no trace (which it may do, at its discretion, e.g., if it doesn't
 688  * care to issue a lease on the negative dentry).
 689  */
 690 struct dentry *ceph_finish_lookup(struct ceph_mds_request *req,
 691                                   struct dentry *dentry, int err)
 692 {
 693         if (err == -ENOENT) {
 694                 /* no trace? */
 695                 err = 0;
 696                 if (!req->r_reply_info.head->is_dentry) {
 697                         dout("ENOENT and no trace, dentry %p inode %p\n",
 698                              dentry, d_inode(dentry));
 699                         if (d_really_is_positive(dentry)) {
 700                                 d_drop(dentry);
 701                                 err = -ENOENT;
 702                         } else {
 703                                 d_add(dentry, NULL);
 704                         }
 705                 }
 706         }
 707         if (err)
 708                 dentry = ERR_PTR(err);
 709         else if (dentry != req->r_dentry)
 710                 dentry = dget(req->r_dentry);   /* we got spliced */
 711         else
 712                 dentry = NULL;
 713         return dentry;
 714 }
 715
 716 static bool is_root_ceph_dentry(struct inode *inode, struct dentry *dentry)
 717 {
 718         return ceph_ino(inode) == CEPH_INO_ROOT &&
 719                 strncmp(dentry->d_name.name, ".ceph", 5) == 0;
 720 }
 721
 722 /*
 723  * Look up a single dir entry.  If there is a lookup intent, inform
 724  * the MDS so that it gets our 'caps wanted' value in a single op.
 725  */
 726 static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
 727                                   unsigned int flags)
 728 {
 729         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
 730         struct ceph_mds_client *mdsc = fsc->mdsc;
 731         struct ceph_mds_request *req;
 732         int op;
 733         int mask;
 734         int err;
 735
 736         dout("lookup %p dentry %p '%pd'\n",
 737              dir, dentry, dentry);
 738
 739         if (dentry->d_name.len > NAME_MAX)
 740                 return ERR_PTR(-ENAMETOOLONG);
 741
 742         /* can we conclude ENOENT locally? */
 743         if (d_really_is_negative(dentry)) {
 744                 struct ceph_inode_info *ci = ceph_inode(dir);
 745                 struct ceph_dentry_info *di = ceph_dentry(dentry);
 746
 747                 spin_lock(&ci->i_ceph_lock);
 748                 dout(" dir %p flags are %d\n", dir, ci->i_ceph_flags);
 749                 if (strncmp(dentry->d_name.name,
 750                             fsc->mount_options->snapdir_name,
 751                             dentry->d_name.len) &&
 752                     !is_root_ceph_dentry(dir, dentry) &&
 753                     ceph_test_mount_opt(fsc, DCACHE) &&
 754                     __ceph_dir_is_complete(ci) &&
 755                     (__ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1))) {
 756                         spin_unlock(&ci->i_ceph_lock);
 757                         dout(" dir %p complete, -ENOENT\n", dir);
 758                         d_add(dentry, NULL);
 759                         di->lease_shared_gen = atomic_read(&ci->i_shared_gen);
 760                         return NULL;
 761                 }
 762                 spin_unlock(&ci->i_ceph_lock);
 763         }
 764
 765         op = ceph_snap(dir) == CEPH_SNAPDIR ?
 766                 CEPH_MDS_OP_LOOKUPSNAP : CEPH_MDS_OP_LOOKUP;
 767         req = ceph_mdsc_create_request(mdsc, op, USE_ANY_MDS);
 768         if (IS_ERR(req))
 769                 return ERR_CAST(req);
 770         req->r_dentry = dget(dentry);
 771         req->r_num_caps = 2;
 772
 773         mask = CEPH_STAT_CAP_INODE | CEPH_CAP_AUTH_SHARED;
 774         if (ceph_security_xattr_wanted(dir))
 775                 mask |= CEPH_CAP_XATTR_SHARED;
 776         req->r_args.getattr.mask = cpu_to_le32(mask);
 777
 778         req->r_parent = dir;
 779         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
 780         err = ceph_mdsc_do_request(mdsc, NULL, req);
 781         err = ceph_handle_snapdir(req, dentry, err);
 782         dentry = ceph_finish_lookup(req, dentry, err);
 783         ceph_mdsc_put_request(req);  /* will dput(dentry) */
 784         dout("lookup result=%p\n", dentry);
 785         return dentry;
 786 }
 787
 788 /*
 789  * If we do a create but get no trace back from the MDS, follow up with
 790  * a lookup (the VFS expects us to link up the provided dentry).
 791  */
 792 int ceph_handle_notrace_create(struct inode *dir, struct dentry *dentry)
 793 {
 794         struct dentry *result = ceph_lookup(dir, dentry, 0);
 795
 796         if (result && !IS_ERR(result)) {
 797                 /*
 798                  * We created the item, then did a lookup, and found
 799                  * it was already linked to another inode we already
 800                  * had in our cache (and thus got spliced). To not
 801                  * confuse VFS (especially when inode is a directory),
 802                  * we don't link our dentry to that inode, return an
 803                  * error instead.
 804                  *
 805                  * This event should be rare and it happens only when
 806                  * we talk to old MDS. Recent MDS does not send traceless
 807                  * reply for request that creates new inode.
 808                  */
 809                 d_drop(result);
 810                 return -ESTALE;
 811         }
 812         return PTR_ERR(result);
 813 }
 814
 815 static int ceph_mknod(struct inode *dir, struct dentry *dentry,
 816                       umode_t mode, dev_t rdev)
 817 {
 818         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
 819         struct ceph_mds_client *mdsc = fsc->mdsc;
 820         struct ceph_mds_request *req;
 821         struct ceph_acls_info acls = {};
 822         int err;
 823
 824         if (ceph_snap(dir) != CEPH_NOSNAP)
 825                 return -EROFS;
 826
 827         err = ceph_pre_init_acls(dir, &mode, &acls);
 828         if (err < 0)
 829                 return err;
 830
 831         dout("mknod in dir %p dentry %p mode 0%ho rdev %d\n",
 832              dir, dentry, mode, rdev);
 833         req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_MKNOD, USE_AUTH_MDS);
 834         if (IS_ERR(req)) {
 835                 err = PTR_ERR(req);
 836                 goto out;
 837         }
 838         req->r_dentry = dget(dentry);
 839         req->r_num_caps = 2;
 840         req->r_parent = dir;
 841         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
 842         req->r_args.mknod.mode = cpu_to_le32(mode);
 843         req->r_args.mknod.rdev = cpu_to_le32(rdev);
 844         req->r_dentry_drop = CEPH_CAP_FILE_SHARED | CEPH_CAP_AUTH_EXCL;
 845         req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
 846         if (acls.pagelist) {
 847                 req->r_pagelist = acls.pagelist;
 848                 acls.pagelist = NULL;
 849         }
 850         err = ceph_mdsc_do_request(mdsc, dir, req);
 851         if (!err && !req->r_reply_info.head->is_dentry)
 852                 err = ceph_handle_notrace_create(dir, dentry);
 853         ceph_mdsc_put_request(req);
 854 out:
 855         if (!err)
 856                 ceph_init_inode_acls(d_inode(dentry), &acls);
 857         else
 858                 d_drop(dentry);
 859         ceph_release_acls_info(&acls);
 860         return err;
 861 }
 862
 863 static int ceph_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 864                        bool excl)
 865 {
 866         return ceph_mknod(dir, dentry, mode, 0);
 867 }
 868
 869 static int ceph_symlink(struct inode *dir, struct dentry *dentry,
 870                             const char *dest)
 871 {
 872         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
 873         struct ceph_mds_client *mdsc = fsc->mdsc;
 874         struct ceph_mds_request *req;
 875         int err;
 876
 877         if (ceph_snap(dir) != CEPH_NOSNAP)
 878                 return -EROFS;
 879
 880         dout("symlink in dir %p dentry %p to '%s'\n", dir, dentry, dest);
 881         req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SYMLINK, USE_AUTH_MDS);
 882         if (IS_ERR(req)) {
 883                 err = PTR_ERR(req);
 884                 goto out;
 885         }
 886         req->r_path2 = kstrdup(dest, GFP_KERNEL);
 887         if (!req->r_path2) {
 888                 err = -ENOMEM;
 889                 ceph_mdsc_put_request(req);
 890                 goto out;
 891         }
 892         req->r_parent = dir;
 893         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
 894         req->r_dentry = dget(dentry);
 895         req->r_num_caps = 2;
 896         req->r_dentry_drop = CEPH_CAP_FILE_SHARED | CEPH_CAP_AUTH_EXCL;
 897         req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
 898         err = ceph_mdsc_do_request(mdsc, dir, req);
 899         if (!err && !req->r_reply_info.head->is_dentry)
 900                 err = ceph_handle_notrace_create(dir, dentry);
 901         ceph_mdsc_put_request(req);
 902 out:
 903         if (err)
 904                 d_drop(dentry);
 905         return err;
 906 }
 907
 908 static int ceph_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 909 {
 910         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
 911         struct ceph_mds_client *mdsc = fsc->mdsc;
 912         struct ceph_mds_request *req;
 913         struct ceph_acls_info acls = {};
 914         int err = -EROFS;
 915         int op;
 916
 917         if (ceph_snap(dir) == CEPH_SNAPDIR) {
 918                 /* mkdir .snap/foo is a MKSNAP */
 919                 op = CEPH_MDS_OP_MKSNAP;
 920                 dout("mksnap dir %p snap '%pd' dn %p\n", dir,
 921                      dentry, dentry);
 922         } else if (ceph_snap(dir) == CEPH_NOSNAP) {
 923                 dout("mkdir dir %p dn %p mode 0%ho\n", dir, dentry, mode);
 924                 op = CEPH_MDS_OP_MKDIR;
 925         } else {
 926                 goto out;
 927         }
 928
 929         mode |= S_IFDIR;
 930         err = ceph_pre_init_acls(dir, &mode, &acls);
 931         if (err < 0)
 932                 goto out;
 933
 934         req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
 935         if (IS_ERR(req)) {
 936                 err = PTR_ERR(req);
 937                 goto out;
 938         }
 939
 940         req->r_dentry = dget(dentry);
 941         req->r_num_caps = 2;
 942         req->r_parent = dir;
 943         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
 944         req->r_args.mkdir.mode = cpu_to_le32(mode);
 945         req->r_dentry_drop = CEPH_CAP_FILE_SHARED | CEPH_CAP_AUTH_EXCL;
 946         req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
 947         if (acls.pagelist) {
 948                 req->r_pagelist = acls.pagelist;
 949                 acls.pagelist = NULL;
 950         }
 951         err = ceph_mdsc_do_request(mdsc, dir, req);
 952         if (!err &&
 953             !req->r_reply_info.head->is_target &&
 954             !req->r_reply_info.head->is_dentry)
 955                 err = ceph_handle_notrace_create(dir, dentry);
 956         ceph_mdsc_put_request(req);
 957 out:
 958         if (!err)
 959                 ceph_init_inode_acls(d_inode(dentry), &acls);
 960         else
 961                 d_drop(dentry);
 962         ceph_release_acls_info(&acls);
 963         return err;
 964 }
 965
 966 static int ceph_link(struct dentry *old_dentry, struct inode *dir,
 967                      struct dentry *dentry)
 968 {
 969         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
 970         struct ceph_mds_client *mdsc = fsc->mdsc;
 971         struct ceph_mds_request *req;
 972         int err;
 973
 974         if (ceph_snap(dir) != CEPH_NOSNAP)
 975                 return -EROFS;
 976
 977         dout("link in dir %p old_dentry %p dentry %p\n", dir,
 978              old_dentry, dentry);
 979         req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LINK, USE_AUTH_MDS);
 980         if (IS_ERR(req)) {
 981                 d_drop(dentry);
 982                 return PTR_ERR(req);
 983         }
 984         req->r_dentry = dget(dentry);
 985         req->r_num_caps = 2;
 986         req->r_old_dentry = dget(old_dentry);
 987         req->r_parent = dir;
 988         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
 989         req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
 990         req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
 991         /* release LINK_SHARED on source inode (mds will lock it) */
 992         req->r_old_inode_drop = CEPH_CAP_LINK_SHARED | CEPH_CAP_LINK_EXCL;
 993         err = ceph_mdsc_do_request(mdsc, dir, req);
 994         if (err) {
 995                 d_drop(dentry);
 996         } else if (!req->r_reply_info.head->is_dentry) {
 997                 ihold(d_inode(old_dentry));
 998                 d_instantiate(dentry, d_inode(old_dentry));
 999         }
1000         ceph_mdsc_put_request(req);
1001         return err;
1002 }
1003
1004 /*
1005  * rmdir and unlink are differ only by the metadata op code
1006  */
1007 static int ceph_unlink(struct inode *dir, struct dentry *dentry)
1008 {
1009         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
1010         struct ceph_mds_client *mdsc = fsc->mdsc;
1011         struct inode *inode = d_inode(dentry);
1012         struct ceph_mds_request *req;
1013         int err = -EROFS;
1014         int op;
1015
1016         if (ceph_snap(dir) == CEPH_SNAPDIR) {
1017                 /* rmdir .snap/foo is RMSNAP */
1018                 dout("rmsnap dir %p '%pd' dn %p\n", dir, dentry, dentry);
1019                 op = CEPH_MDS_OP_RMSNAP;
1020         } else if (ceph_snap(dir) == CEPH_NOSNAP) {
1021                 dout("unlink/rmdir dir %p dn %p inode %p\n",
1022                      dir, dentry, inode);
1023                 op = d_is_dir(dentry) ?
1024                         CEPH_MDS_OP_RMDIR : CEPH_MDS_OP_UNLINK;
1025         } else
1026                 goto out;
1027         req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
1028         if (IS_ERR(req)) {
1029                 err = PTR_ERR(req);
1030                 goto out;
1031         }
1032         req->r_dentry = dget(dentry);
1033         req->r_num_caps = 2;
1034         req->r_parent = dir;
1035         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
1036         req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
1037         req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
1038         req->r_inode_drop = ceph_drop_caps_for_unlink(inode);
1039         err = ceph_mdsc_do_request(mdsc, dir, req);
1040         if (!err && !req->r_reply_info.head->is_dentry)
1041                 d_delete(dentry);
1042         ceph_mdsc_put_request(req);
1043 out:
1044         return err;
1045 }
1046
1047 static int ceph_rename(struct inode *old_dir, struct dentry *old_dentry,
1048                        struct inode *new_dir, struct dentry *new_dentry,
1049                        unsigned int flags)
1050 {
1051         struct ceph_fs_client *fsc = ceph_sb_to_client(old_dir->i_sb);
1052         struct ceph_mds_client *mdsc = fsc->mdsc;
1053         struct ceph_mds_request *req;
1054         int op = CEPH_MDS_OP_RENAME;
1055         int err;
1056
1057         if (flags)
1058                 return -EINVAL;
1059
1060         if (ceph_snap(old_dir) != ceph_snap(new_dir))
1061                 return -EXDEV;
1062         if (ceph_snap(old_dir) != CEPH_NOSNAP) {
1063                 if (old_dir == new_dir && ceph_snap(old_dir) == CEPH_SNAPDIR)
1064                         op = CEPH_MDS_OP_RENAMESNAP;
1065                 else
1066                         return -EROFS;
1067         }
1068         dout("rename dir %p dentry %p to dir %p dentry %p\n",
1069              old_dir, old_dentry, new_dir, new_dentry);
1070         req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
1071         if (IS_ERR(req))
1072                 return PTR_ERR(req);
1073         ihold(old_dir);
1074         req->r_dentry = dget(new_dentry);
1075         req->r_num_caps = 2;
1076         req->r_old_dentry = dget(old_dentry);
1077         req->r_old_dentry_dir = old_dir;
1078         req->r_parent = new_dir;
1079         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
1080         req->r_old_dentry_drop = CEPH_CAP_FILE_SHARED;
1081         req->r_old_dentry_unless = CEPH_CAP_FILE_EXCL;
1082         req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
1083         req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
1084         /* release LINK_RDCACHE on source inode (mds will lock it) */
1085         req->r_old_inode_drop = CEPH_CAP_LINK_SHARED | CEPH_CAP_LINK_EXCL;
1086         if (d_really_is_positive(new_dentry)) {
1087                 req->r_inode_drop =
1088                         ceph_drop_caps_for_unlink(d_inode(new_dentry));
1089         }
1090         err = ceph_mdsc_do_request(mdsc, old_dir, req);
1091         if (!err && !req->r_reply_info.head->is_dentry) {
1092                 /*
1093                  * Normally d_move() is done by fill_trace (called by
1094                  * do_request, above).  If there is no trace, we need
1095                  * to do it here.
1096                  */
1097                 d_move(old_dentry, new_dentry);
1098         }
1099         ceph_mdsc_put_request(req);
1100         return err;
1101 }
1102
1103 /*
1104  * Ensure a dentry lease will no longer revalidate.
1105  */
1106 void ceph_invalidate_dentry_lease(struct dentry *dentry)
1107 {
1108         spin_lock(&dentry->d_lock);
1109         ceph_dentry(dentry)->time = jiffies;
1110         ceph_dentry(dentry)->lease_shared_gen = 0;
1111         spin_unlock(&dentry->d_lock);
1112 }
1113
1114 /*
1115  * Check if dentry lease is valid.  If not, delete the lease.  Try to
1116  * renew if the least is more than half up.
1117  */
1118 static int dentry_lease_is_valid(struct dentry *dentry, unsigned int flags,
1119                                  struct inode *dir)
1120 {
1121         struct ceph_dentry_info *di;
1122         struct ceph_mds_session *s;
1123         int valid = 0;
1124         u32 gen;
1125         unsigned long ttl;
1126         struct ceph_mds_session *session = NULL;
1127         u32 seq = 0;
1128
1129         spin_lock(&dentry->d_lock);
1130         di = ceph_dentry(dentry);
1131         if (di && di->lease_session) {
1132                 s = di->lease_session;
1133                 spin_lock(&s->s_gen_ttl_lock);
1134                 gen = s->s_cap_gen;
1135                 ttl = s->s_cap_ttl;
1136                 spin_unlock(&s->s_gen_ttl_lock);
1137
1138                 if (di->lease_gen == gen &&
1139                     time_before(jiffies, di->time) &&
1140                     time_before(jiffies, ttl)) {
1141                         valid = 1;
1142                         if (di->lease_renew_after &&
1143                             time_after(jiffies, di->lease_renew_after)) {
1144                                 /*
1145                                  * We should renew. If we're in RCU walk mode
1146                                  * though, we can't do that so just return
1147                                  * -ECHILD.
1148                                  */
1149                                 if (flags & LOOKUP_RCU) {
1150                                         valid = -ECHILD;
1151                                 } else {
1152                                         session = ceph_get_mds_session(s);
1153                                         seq = di->lease_seq;
1154                                         di->lease_renew_after = 0;
1155                                         di->lease_renew_from = jiffies;
1156                                 }
1157                         }
1158                 }
1159         }
1160         spin_unlock(&dentry->d_lock);
1161
1162         if (session) {
1163                 ceph_mdsc_lease_send_msg(session, dir, dentry,
1164                                          CEPH_MDS_LEASE_RENEW, seq);
1165                 ceph_put_mds_session(session);
1166         }
1167         dout("dentry_lease_is_valid - dentry %p = %d\n", dentry, valid);
1168         return valid;
1169 }
1170
1171 /*
1172  * Check if directory-wide content lease/cap is valid.
1173  */
1174 static int dir_lease_is_valid(struct inode *dir, struct dentry *dentry)
1175 {
1176         struct ceph_inode_info *ci = ceph_inode(dir);
1177         struct ceph_dentry_info *di = ceph_dentry(dentry);
1178         int valid = 0;
1179
1180         spin_lock(&ci->i_ceph_lock);
1181         if (atomic_read(&ci->i_shared_gen) == di->lease_shared_gen)
1182                 valid = __ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1);
1183         spin_unlock(&ci->i_ceph_lock);
1184         dout("dir_lease_is_valid dir %p v%u dentry %p v%u = %d\n",
1185              dir, (unsigned)atomic_read(&ci->i_shared_gen),
1186              dentry, (unsigned)di->lease_shared_gen, valid);
1187         return valid;
1188 }
1189
1190 /*
1191  * Check if cached dentry can be trusted.
1192  */
1193 static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
1194 {
1195         int valid = 0;
1196         struct dentry *parent;
1197         struct inode *dir;
1198
1199         if (flags & LOOKUP_RCU) {
1200                 parent = READ_ONCE(dentry->d_parent);
1201                 dir = d_inode_rcu(parent);
1202                 if (!dir)
1203                         return -ECHILD;
1204         } else {
1205                 parent = dget_parent(dentry);
1206                 dir = d_inode(parent);
1207         }
1208
1209         dout("d_revalidate %p '%pd' inode %p offset %lld\n", dentry,
1210              dentry, d_inode(dentry), ceph_dentry(dentry)->offset);
1211
1212         /* always trust cached snapped dentries, snapdir dentry */
1213         if (ceph_snap(dir) != CEPH_NOSNAP) {
1214                 dout("d_revalidate %p '%pd' inode %p is SNAPPED\n", dentry,
1215                      dentry, d_inode(dentry));
1216                 valid = 1;
1217         } else if (d_really_is_positive(dentry) &&
1218                    ceph_snap(d_inode(dentry)) == CEPH_SNAPDIR) {
1219                 valid = 1;
1220         } else {
1221                 valid = dentry_lease_is_valid(dentry, flags, dir);
1222                 if (valid == -ECHILD)
1223                         return valid;
1224                 if (valid || dir_lease_is_valid(dir, dentry)) {
1225                         if (d_really_is_positive(dentry))
1226                                 valid = ceph_is_any_caps(d_inode(dentry));
1227                         else
1228                                 valid = 1;
1229                 }
1230         }
1231
1232         if (!valid) {
1233                 struct ceph_mds_client *mdsc =
1234                         ceph_sb_to_client(dir->i_sb)->mdsc;
1235                 struct ceph_mds_request *req;
1236                 int op, err;
1237                 u32 mask;
1238
1239                 if (flags & LOOKUP_RCU)
1240                         return -ECHILD;
1241
1242                 op = ceph_snap(dir) == CEPH_SNAPDIR ?
1243                         CEPH_MDS_OP_LOOKUPSNAP : CEPH_MDS_OP_LOOKUP;
1244                 req = ceph_mdsc_create_request(mdsc, op, USE_ANY_MDS);
1245                 if (!IS_ERR(req)) {
1246                         req->r_dentry = dget(dentry);
1247                         req->r_num_caps = 2;
1248                         req->r_parent = dir;
1249
1250                         mask = CEPH_STAT_CAP_INODE | CEPH_CAP_AUTH_SHARED;
1251                         if (ceph_security_xattr_wanted(dir))
1252                                 mask |= CEPH_CAP_XATTR_SHARED;
1253                         req->r_args.getattr.mask = cpu_to_le32(mask);
1254
1255                         err = ceph_mdsc_do_request(mdsc, NULL, req);
1256                         switch (err) {
1257                         case 0:
1258                                 if (d_really_is_positive(dentry) &&
1259                                     d_inode(dentry) == req->r_target_inode)
1260                                         valid = 1;
1261                                 break;
1262                         case -ENOENT:
1263                                 if (d_really_is_negative(dentry))
1264                                         valid = 1;
1265                                 /* Fallthrough */
1266                         default:
1267                                 break;
1268                         }
1269                         ceph_mdsc_put_request(req);
1270                         dout("d_revalidate %p lookup result=%d\n",
1271                              dentry, err);
1272                 }
1273         }
1274
1275         dout("d_revalidate %p %s\n", dentry, valid ? "valid" : "invalid");
1276         if (valid) {
1277                 ceph_dentry_lru_touch(dentry);
1278         } else {
1279                 ceph_dir_clear_complete(dir);
1280         }
1281
1282         if (!(flags & LOOKUP_RCU))
1283                 dput(parent);
1284         return valid;
1285 }
1286
1287 /*
1288  * Release our ceph_dentry_info.
1289  */
1290 static void ceph_d_release(struct dentry *dentry)
1291 {
1292         struct ceph_dentry_info *di = ceph_dentry(dentry);
1293
1294         dout("d_release %p\n", dentry);
1295         ceph_dentry_lru_del(dentry);
1296
1297         spin_lock(&dentry->d_lock);
1298         dentry->d_fsdata = NULL;
1299         spin_unlock(&dentry->d_lock);
1300
1301         if (di->lease_session)
1302                 ceph_put_mds_session(di->lease_session);
1303         kmem_cache_free(ceph_dentry_cachep, di);
1304 }
1305
1306 /*
1307  * When the VFS prunes a dentry from the cache, we need to clear the
1308  * complete flag on the parent directory.
1309  *
1310  * Called under dentry->d_lock.
1311  */
1312 static void ceph_d_prune(struct dentry *dentry)
1313 {
1314         struct ceph_inode_info *dir_ci;
1315         struct ceph_dentry_info *di;
1316
1317         dout("ceph_d_prune %pd %p\n", dentry, dentry);
1318
1319         /* do we have a valid parent? */
1320         if (IS_ROOT(dentry))
1321                 return;
1322
1323         /* we hold d_lock, so d_parent is stable */
1324         dir_ci = ceph_inode(d_inode(dentry->d_parent));
1325         if (dir_ci->i_vino.snap == CEPH_SNAPDIR)
1326                 return;
1327
1328         /* who calls d_delete() should also disable dcache readdir */
1329         if (d_really_is_negative(dentry))
1330                 return;
1331
1332         /* d_fsdata does not get cleared until d_release */
1333         if (!d_unhashed(dentry)) {
1334                 __ceph_dir_clear_complete(dir_ci);
1335                 return;
1336         }
1337
1338         /* Disable dcache readdir just in case that someone called d_drop()
1339          * or d_invalidate(), but MDS didn't revoke CEPH_CAP_FILE_SHARED
1340          * properly (dcache readdir is still enabled) */
1341         di = ceph_dentry(dentry);
1342         if (di->offset > 0 &&
1343             di->lease_shared_gen == atomic_read(&dir_ci->i_shared_gen))
1344                 __ceph_dir_clear_ordered(dir_ci);
1345 }
1346
1347 /*
1348  * read() on a dir.  This weird interface hack only works if mounted
1349  * with '-o dirstat'.
1350  */
1351 static ssize_t ceph_read_dir(struct file *file, char __user *buf, size_t size,
1352                              loff_t *ppos)
1353 {
1354         struct ceph_file_info *cf = file->private_data;
1355         struct inode *inode = file_inode(file);
1356         struct ceph_inode_info *ci = ceph_inode(inode);
1357         int left;
1358         const int bufsize = 1024;
1359
1360         if (!ceph_test_mount_opt(ceph_sb_to_client(inode->i_sb), DIRSTAT))
1361                 return -EISDIR;
1362
1363         if (!cf->dir_info) {
1364                 cf->dir_info = kmalloc(bufsize, GFP_KERNEL);
1365                 if (!cf->dir_info)
1366                         return -ENOMEM;
1367                 cf->dir_info_len =
1368                         snprintf(cf->dir_info, bufsize,
1369                                 "entries:   %20lld\n"
1370                                 " files:    %20lld\n"
1371                                 " subdirs:  %20lld\n"
1372                                 "rentries:  %20lld\n"
1373                                 " rfiles:   %20lld\n"
1374                                 " rsubdirs: %20lld\n"
1375                                 "rbytes:    %20lld\n"
1376                                 "rctime:    %10ld.%09ld\n",
1377                                 ci->i_files + ci->i_subdirs,
1378                                 ci->i_files,
1379                                 ci->i_subdirs,
1380                                 ci->i_rfiles + ci->i_rsubdirs,
1381                                 ci->i_rfiles,
1382                                 ci->i_rsubdirs,
1383                                 ci->i_rbytes,
1384                                 (long)ci->i_rctime.tv_sec,
1385                                 (long)ci->i_rctime.tv_nsec);
1386         }
1387
1388         if (*ppos >= cf->dir_info_len)
1389                 return 0;
1390         size = min_t(unsigned, size, cf->dir_info_len-*ppos);
1391         left = copy_to_user(buf, cf->dir_info + *ppos, size);
1392         if (left == size)
1393                 return -EFAULT;
1394         *ppos += (size - left);
1395         return size - left;
1396 }
1397
1398 /*
1399  * We maintain a private dentry LRU.
1400  *
1401  * FIXME: this needs to be changed to a per-mds lru to be useful.
1402  */
1403 void ceph_dentry_lru_add(struct dentry *dn)
1404 {
1405         struct ceph_dentry_info *di = ceph_dentry(dn);
1406         struct ceph_mds_client *mdsc;
1407
1408         dout("dentry_lru_add %p %p '%pd'\n", di, dn, dn);
1409         mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
1410         spin_lock(&mdsc->dentry_lru_lock);
1411         list_add_tail(&di->lru, &mdsc->dentry_lru);
1412         mdsc->num_dentry++;
1413         spin_unlock(&mdsc->dentry_lru_lock);
1414 }
1415
1416 void ceph_dentry_lru_touch(struct dentry *dn)
1417 {
1418         struct ceph_dentry_info *di = ceph_dentry(dn);
1419         struct ceph_mds_client *mdsc;
1420
1421         dout("dentry_lru_touch %p %p '%pd' (offset %lld)\n", di, dn, dn,
1422              di->offset);
1423         mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
1424         spin_lock(&mdsc->dentry_lru_lock);
1425         list_move_tail(&di->lru, &mdsc->dentry_lru);
1426         spin_unlock(&mdsc->dentry_lru_lock);
1427 }
1428
1429 void ceph_dentry_lru_del(struct dentry *dn)
1430 {
1431         struct ceph_dentry_info *di = ceph_dentry(dn);
1432         struct ceph_mds_client *mdsc;
1433
1434         dout("dentry_lru_del %p %p '%pd'\n", di, dn, dn);
1435         mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
1436         spin_lock(&mdsc->dentry_lru_lock);
1437         list_del_init(&di->lru);
1438         mdsc->num_dentry--;
1439         spin_unlock(&mdsc->dentry_lru_lock);
1440 }
1441
1442 /*
1443  * Return name hash for a given dentry.  This is dependent on
1444  * the parent directory's hash function.
1445  */
1446 unsigned ceph_dentry_hash(struct inode *dir, struct dentry *dn)
1447 {
1448         struct ceph_inode_info *dci = ceph_inode(dir);
1449
1450         switch (dci->i_dir_layout.dl_dir_hash) {
1451         case 0: /* for backward compat */
1452         case CEPH_STR_HASH_LINUX:
1453                 return dn->d_name.hash;
1454
1455         default:
1456                 return ceph_str_hash(dci->i_dir_layout.dl_dir_hash,
1457                                      dn->d_name.name, dn->d_name.len);
1458         }
1459 }
1460
1461 const struct file_operations ceph_dir_fops = {
1462         .read = ceph_read_dir,
1463         .iterate = ceph_readdir,
1464         .llseek = ceph_dir_llseek,
1465         .open = ceph_open,
1466         .release = ceph_release,
1467         .unlocked_ioctl = ceph_ioctl,
1468         .fsync = ceph_fsync,
1469 };
1470
1471 const struct file_operations ceph_snapdir_fops = {
1472         .iterate = ceph_readdir,
1473         .llseek = ceph_dir_llseek,
1474         .open = ceph_open,
1475         .release = ceph_release,
1476 };
1477
1478 const struct inode_operations ceph_dir_iops = {
1479         .lookup = ceph_lookup,
1480         .permission = ceph_permission,
1481         .getattr = ceph_getattr,
1482         .setattr = ceph_setattr,
1483         .listxattr = ceph_listxattr,
1484         .get_acl = ceph_get_acl,
1485         .set_acl = ceph_set_acl,
1486         .mknod = ceph_mknod,
1487         .symlink = ceph_symlink,
1488         .mkdir = ceph_mkdir,
1489         .link = ceph_link,
1490         .unlink = ceph_unlink,
1491         .rmdir = ceph_unlink,
1492         .rename = ceph_rename,
1493         .create = ceph_create,
1494         .atomic_open = ceph_atomic_open,
1495 };
1496
1497 const struct inode_operations ceph_snapdir_iops = {
1498         .lookup = ceph_lookup,
1499         .permission = ceph_permission,
1500         .getattr = ceph_getattr,
1501         .mkdir = ceph_mkdir,
1502         .rmdir = ceph_unlink,
1503         .rename = ceph_rename,
1504 };
1505
1506 const struct dentry_operations ceph_dentry_ops = {
1507         .d_revalidate = ceph_d_revalidate,
1508         .d_release = ceph_d_release,
1509         .d_prune = ceph_d_prune,
1510         .d_init = ceph_d_init,
1511 };