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TOMOYO Linux Cross Reference
Linux/fs/ceph/dir.c

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

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