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

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  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_dir_file_info *dfi, 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(dfi->last_name);
111         dfi->last_name = buf;
112         memcpy(dfi->last_name, name, len);
113         dfi->last_name[len] = 0;
114         dfi->next_offset = next_offset;
115         dout("note_last_dentry '%s'\n", dfi->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_dir_file_info *dfi = 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                         dfi->file_info.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(dfi, 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 (dfi->readdir_cache_idx >= 0) {
282                         dfi->readdir_cache_idx = -1;
283                         dfi->dir_release_count = 0;
284                 }
285         }
286         return err;
287 }
288 
289 static bool need_send_readdir(struct ceph_dir_file_info *dfi, loff_t pos)
290 {
291         if (!dfi->last_readdir)
292                 return true;
293         if (is_hash_order(pos))
294                 return !ceph_frag_contains_value(dfi->frag, fpos_hash(pos));
295         else
296                 return dfi->frag != fpos_frag(pos);
297 }
298 
299 static int ceph_readdir(struct file *file, struct dir_context *ctx)
300 {
301         struct ceph_dir_file_info *dfi = 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 (dfi->file_info.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(dfi, 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 (dfi->last_readdir) {
360                         ceph_mdsc_put_request(dfi->last_readdir);
361                         dfi->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, dfi->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 (dfi->last_name) {
392                         req->r_path2 = kstrdup(dfi->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 = dfi->dir_release_count;
403                 req->r_dir_ordered_cnt = dfi->dir_ordered_count;
404                 req->r_readdir_cache_idx = dfi->readdir_cache_idx;
405                 req->r_readdir_offset = dfi->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                                 dfi->next_offset = req->r_readdir_offset;
430                                 /* adjust ctx->pos to beginning of frag */
431                                 ctx->pos = ceph_make_fpos(frag,
432                                                           dfi->next_offset,
433                                                           false);
434                         }
435                 }
436 
437                 dfi->frag = frag;
438                 dfi->last_readdir = req;
439 
440                 if (test_bit(CEPH_MDS_R_DID_PREPOPULATE, &req->r_req_flags)) {
441                         dfi->readdir_cache_idx = req->r_readdir_cache_idx;
442                         if (dfi->readdir_cache_idx < 0) {
443                                 /* preclude from marking dir ordered */
444                                 dfi->dir_ordered_count = 0;
445                         } else if (ceph_frag_is_leftmost(frag) &&
446                                    dfi->next_offset == 2) {
447                                 /* note dir version at start of readdir so
448                                  * we can tell if any dentries get dropped */
449                                 dfi->dir_release_count = req->r_dir_release_cnt;
450                                 dfi->dir_ordered_count = req->r_dir_ordered_cnt;
451                         }
452                 } else {
453                         dout("readdir !did_prepopulate\n");
454                         /* disable readdir cache */
455                         dfi->readdir_cache_idx = -1;
456                         /* preclude from marking dir complete */
457                         dfi->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(dfi, rde->name, rde->name_len,
467                                                next_offset);
468                         if (err)
469                                 return err;
470                 } else if (req->r_reply_info.dir_end) {
471                         dfi->next_offset = 2;
472                         /* keep last name */
473                 }
474         }
475 
476         rinfo = &dfi->last_readdir->r_reply_info;
477         dout("readdir frag %x num %d pos %llx chunk first %llx\n",
478              dfi->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(dfi->last_readdir);
523         dfi->last_readdir = NULL;
524 
525         if (dfi->next_offset > 2) {
526                 frag = dfi->frag;
527                 goto more;
528         }
529 
530         /* more frags? */
531         if (!ceph_frag_is_rightmost(dfi->frag)) {
532                 frag = ceph_frag_next(dfi->frag);
533                 if (is_hash_order(ctx->pos)) {
534                         loff_t new_pos = ceph_make_fpos(ceph_frag_value(frag),
535                                                         dfi->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, dfi->next_offset,
541                                                         false);
542                         kfree(dfi->last_name);
543                         dfi->last_name = NULL;
544                 }
545                 dout("readdir next frag is %x\n", frag);
546                 goto more;
547         }
548         dfi->file_info.flags |= CEPH_F_ATEND;
549 
550         /*
551          * if dir_release_count still matches the dir, no dentries
552          * were released during the whole readdir, and we should have
553          * the complete dir contents in our cache.
554          */
555         if (atomic64_read(&ci->i_release_count) ==
556                                         dfi->dir_release_count) {
557                 spin_lock(&ci->i_ceph_lock);
558                 if (dfi->dir_ordered_count ==
559                                 atomic64_read(&ci->i_ordered_count)) {
560                         dout(" marking %p complete and ordered\n", inode);
561                         /* use i_size to track number of entries in
562                          * readdir cache */
563                         BUG_ON(dfi->readdir_cache_idx < 0);
564                         i_size_write(inode, dfi->readdir_cache_idx *
565                                      sizeof(struct dentry*));
566                 } else {
567                         dout(" marking %p complete\n", inode);
568                 }
569                 __ceph_dir_set_complete(ci, dfi->dir_release_count,
570                                         dfi->dir_ordered_count);
571                 spin_unlock(&ci->i_ceph_lock);
572         }
573 
574         dout("readdir %p file %p done.\n", inode, file);
575         return 0;
576 }
577 
578 static void reset_readdir(struct ceph_dir_file_info *dfi)
579 {
580         if (dfi->last_readdir) {
581                 ceph_mdsc_put_request(dfi->last_readdir);
582                 dfi->last_readdir = NULL;
583         }
584         kfree(dfi->last_name);
585         dfi->last_name = NULL;
586         dfi->dir_release_count = 0;
587         dfi->readdir_cache_idx = -1;
588         dfi->next_offset = 2;  /* compensate for . and .. */
589         dfi->file_info.flags &= ~CEPH_F_ATEND;
590 }
591 
592 /*
593  * discard buffered readdir content on seekdir(0), or seek to new frag,
594  * or seek prior to current chunk
595  */
596 static bool need_reset_readdir(struct ceph_dir_file_info *dfi, loff_t new_pos)
597 {
598         struct ceph_mds_reply_info_parsed *rinfo;
599         loff_t chunk_offset;
600         if (new_pos == 0)
601                 return true;
602         if (is_hash_order(new_pos)) {
603                 /* no need to reset last_name for a forward seek when
604                  * dentries are sotred in hash order */
605         } else if (dfi->frag != fpos_frag(new_pos)) {
606                 return true;
607         }
608         rinfo = dfi->last_readdir ? &dfi->last_readdir->r_reply_info : NULL;
609         if (!rinfo || !rinfo->dir_nr)
610                 return true;
611         chunk_offset = rinfo->dir_entries[0].offset;
612         return new_pos < chunk_offset ||
613                is_hash_order(new_pos) != is_hash_order(chunk_offset);
614 }
615 
616 static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
617 {
618         struct ceph_dir_file_info *dfi = file->private_data;
619         struct inode *inode = file->f_mapping->host;
620         loff_t retval;
621 
622         inode_lock(inode);
623         retval = -EINVAL;
624         switch (whence) {
625         case SEEK_CUR:
626                 offset += file->f_pos;
627         case SEEK_SET:
628                 break;
629         case SEEK_END:
630                 retval = -EOPNOTSUPP;
631         default:
632                 goto out;
633         }
634 
635         if (offset >= 0) {
636                 if (need_reset_readdir(dfi, offset)) {
637                         dout("dir_llseek dropping %p content\n", file);
638                         reset_readdir(dfi);
639                 } else if (is_hash_order(offset) && offset > file->f_pos) {
640                         /* for hash offset, we don't know if a forward seek
641                          * is within same frag */
642                         dfi->dir_release_count = 0;
643                         dfi->readdir_cache_idx = -1;
644                 }
645 
646                 if (offset != file->f_pos) {
647                         file->f_pos = offset;
648                         file->f_version = 0;
649                         dfi->file_info.flags &= ~CEPH_F_ATEND;
650                 }
651                 retval = offset;
652         }
653 out:
654         inode_unlock(inode);
655         return retval;
656 }
657 
658 /*
659  * Handle lookups for the hidden .snap directory.
660  */
661 int ceph_handle_snapdir(struct ceph_mds_request *req,
662                         struct dentry *dentry, int err)
663 {
664         struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
665         struct inode *parent = d_inode(dentry->d_parent); /* we hold i_mutex */
666 
667         /* .snap dir? */
668         if (err == -ENOENT &&
669             ceph_snap(parent) == CEPH_NOSNAP &&
670             strcmp(dentry->d_name.name,
671                    fsc->mount_options->snapdir_name) == 0) {
672                 struct inode *inode = ceph_get_snapdir(parent);
673                 dout("ENOENT on snapdir %p '%pd', linking to snapdir %p\n",
674                      dentry, dentry, inode);
675                 BUG_ON(!d_unhashed(dentry));
676                 d_add(dentry, inode);
677                 err = 0;
678         }
679         return err;
680 }
681 
682 /*
683  * Figure out final result of a lookup/open request.
684  *
685  * Mainly, make sure we return the final req->r_dentry (if it already
686  * existed) in place of the original VFS-provided dentry when they
687  * differ.
688  *
689  * Gracefully handle the case where the MDS replies with -ENOENT and
690  * no trace (which it may do, at its discretion, e.g., if it doesn't
691  * care to issue a lease on the negative dentry).
692  */
693 struct dentry *ceph_finish_lookup(struct ceph_mds_request *req,
694                                   struct dentry *dentry, int err)
695 {
696         if (err == -ENOENT) {
697                 /* no trace? */
698                 err = 0;
699                 if (!req->r_reply_info.head->is_dentry) {
700                         dout("ENOENT and no trace, dentry %p inode %p\n",
701                              dentry, d_inode(dentry));
702                         if (d_really_is_positive(dentry)) {
703                                 d_drop(dentry);
704                                 err = -ENOENT;
705                         } else {
706                                 d_add(dentry, NULL);
707                         }
708                 }
709         }
710         if (err)
711                 dentry = ERR_PTR(err);
712         else if (dentry != req->r_dentry)
713                 dentry = dget(req->r_dentry);   /* we got spliced */
714         else
715                 dentry = NULL;
716         return dentry;
717 }
718 
719 static bool is_root_ceph_dentry(struct inode *inode, struct dentry *dentry)
720 {
721         return ceph_ino(inode) == CEPH_INO_ROOT &&
722                 strncmp(dentry->d_name.name, ".ceph", 5) == 0;
723 }
724 
725 /*
726  * Look up a single dir entry.  If there is a lookup intent, inform
727  * the MDS so that it gets our 'caps wanted' value in a single op.
728  */
729 static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
730                                   unsigned int flags)
731 {
732         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
733         struct ceph_mds_client *mdsc = fsc->mdsc;
734         struct ceph_mds_request *req;
735         int op;
736         int mask;
737         int err;
738 
739         dout("lookup %p dentry %p '%pd'\n",
740              dir, dentry, dentry);
741 
742         if (dentry->d_name.len > NAME_MAX)
743                 return ERR_PTR(-ENAMETOOLONG);
744 
745         /* can we conclude ENOENT locally? */
746         if (d_really_is_negative(dentry)) {
747                 struct ceph_inode_info *ci = ceph_inode(dir);
748                 struct ceph_dentry_info *di = ceph_dentry(dentry);
749 
750                 spin_lock(&ci->i_ceph_lock);
751                 dout(" dir %p flags are %d\n", dir, ci->i_ceph_flags);
752                 if (strncmp(dentry->d_name.name,
753                             fsc->mount_options->snapdir_name,
754                             dentry->d_name.len) &&
755                     !is_root_ceph_dentry(dir, dentry) &&
756                     ceph_test_mount_opt(fsc, DCACHE) &&
757                     __ceph_dir_is_complete(ci) &&
758                     (__ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1))) {
759                         spin_unlock(&ci->i_ceph_lock);
760                         dout(" dir %p complete, -ENOENT\n", dir);
761                         d_add(dentry, NULL);
762                         di->lease_shared_gen = atomic_read(&ci->i_shared_gen);
763                         return NULL;
764                 }
765                 spin_unlock(&ci->i_ceph_lock);
766         }
767 
768         op = ceph_snap(dir) == CEPH_SNAPDIR ?
769                 CEPH_MDS_OP_LOOKUPSNAP : CEPH_MDS_OP_LOOKUP;
770         req = ceph_mdsc_create_request(mdsc, op, USE_ANY_MDS);
771         if (IS_ERR(req))
772                 return ERR_CAST(req);
773         req->r_dentry = dget(dentry);
774         req->r_num_caps = 2;
775 
776         mask = CEPH_STAT_CAP_INODE | CEPH_CAP_AUTH_SHARED;
777         if (ceph_security_xattr_wanted(dir))
778                 mask |= CEPH_CAP_XATTR_SHARED;
779         req->r_args.getattr.mask = cpu_to_le32(mask);
780 
781         req->r_parent = dir;
782         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
783         err = ceph_mdsc_do_request(mdsc, NULL, req);
784         err = ceph_handle_snapdir(req, dentry, err);
785         dentry = ceph_finish_lookup(req, dentry, err);
786         ceph_mdsc_put_request(req);  /* will dput(dentry) */
787         dout("lookup result=%p\n", dentry);
788         return dentry;
789 }
790 
791 /*
792  * If we do a create but get no trace back from the MDS, follow up with
793  * a lookup (the VFS expects us to link up the provided dentry).
794  */
795 int ceph_handle_notrace_create(struct inode *dir, struct dentry *dentry)
796 {
797         struct dentry *result = ceph_lookup(dir, dentry, 0);
798 
799         if (result && !IS_ERR(result)) {
800                 /*
801                  * We created the item, then did a lookup, and found
802                  * it was already linked to another inode we already
803                  * had in our cache (and thus got spliced). To not
804                  * confuse VFS (especially when inode is a directory),
805                  * we don't link our dentry to that inode, return an
806                  * error instead.
807                  *
808                  * This event should be rare and it happens only when
809                  * we talk to old MDS. Recent MDS does not send traceless
810                  * reply for request that creates new inode.
811                  */
812                 d_drop(result);
813                 return -ESTALE;
814         }
815         return PTR_ERR(result);
816 }
817 
818 static int ceph_mknod(struct inode *dir, struct dentry *dentry,
819                       umode_t mode, dev_t rdev)
820 {
821         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
822         struct ceph_mds_client *mdsc = fsc->mdsc;
823         struct ceph_mds_request *req;
824         struct ceph_acls_info acls = {};
825         int err;
826 
827         if (ceph_snap(dir) != CEPH_NOSNAP)
828                 return -EROFS;
829 
830         if (ceph_quota_is_max_files_exceeded(dir))
831                 return -EDQUOT;
832 
833         err = ceph_pre_init_acls(dir, &mode, &acls);
834         if (err < 0)
835                 return err;
836 
837         dout("mknod in dir %p dentry %p mode 0%ho rdev %d\n",
838              dir, dentry, mode, rdev);
839         req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_MKNOD, USE_AUTH_MDS);
840         if (IS_ERR(req)) {
841                 err = PTR_ERR(req);
842                 goto out;
843         }
844         req->r_dentry = dget(dentry);
845         req->r_num_caps = 2;
846         req->r_parent = dir;
847         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
848         req->r_args.mknod.mode = cpu_to_le32(mode);
849         req->r_args.mknod.rdev = cpu_to_le32(rdev);
850         req->r_dentry_drop = CEPH_CAP_FILE_SHARED | CEPH_CAP_AUTH_EXCL;
851         req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
852         if (acls.pagelist) {
853                 req->r_pagelist = acls.pagelist;
854                 acls.pagelist = NULL;
855         }
856         err = ceph_mdsc_do_request(mdsc, dir, req);
857         if (!err && !req->r_reply_info.head->is_dentry)
858                 err = ceph_handle_notrace_create(dir, dentry);
859         ceph_mdsc_put_request(req);
860 out:
861         if (!err)
862                 ceph_init_inode_acls(d_inode(dentry), &acls);
863         else
864                 d_drop(dentry);
865         ceph_release_acls_info(&acls);
866         return err;
867 }
868 
869 static int ceph_create(struct inode *dir, struct dentry *dentry, umode_t mode,
870                        bool excl)
871 {
872         return ceph_mknod(dir, dentry, mode, 0);
873 }
874 
875 static int ceph_symlink(struct inode *dir, struct dentry *dentry,
876                             const char *dest)
877 {
878         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
879         struct ceph_mds_client *mdsc = fsc->mdsc;
880         struct ceph_mds_request *req;
881         int err;
882 
883         if (ceph_snap(dir) != CEPH_NOSNAP)
884                 return -EROFS;
885 
886         if (ceph_quota_is_max_files_exceeded(dir))
887                 return -EDQUOT;
888 
889         dout("symlink in dir %p dentry %p to '%s'\n", dir, dentry, dest);
890         req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SYMLINK, USE_AUTH_MDS);
891         if (IS_ERR(req)) {
892                 err = PTR_ERR(req);
893                 goto out;
894         }
895         req->r_path2 = kstrdup(dest, GFP_KERNEL);
896         if (!req->r_path2) {
897                 err = -ENOMEM;
898                 ceph_mdsc_put_request(req);
899                 goto out;
900         }
901         req->r_parent = dir;
902         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
903         req->r_dentry = dget(dentry);
904         req->r_num_caps = 2;
905         req->r_dentry_drop = CEPH_CAP_FILE_SHARED | CEPH_CAP_AUTH_EXCL;
906         req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
907         err = ceph_mdsc_do_request(mdsc, dir, req);
908         if (!err && !req->r_reply_info.head->is_dentry)
909                 err = ceph_handle_notrace_create(dir, dentry);
910         ceph_mdsc_put_request(req);
911 out:
912         if (err)
913                 d_drop(dentry);
914         return err;
915 }
916 
917 static int ceph_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
918 {
919         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
920         struct ceph_mds_client *mdsc = fsc->mdsc;
921         struct ceph_mds_request *req;
922         struct ceph_acls_info acls = {};
923         int err = -EROFS;
924         int op;
925 
926         if (ceph_snap(dir) == CEPH_SNAPDIR) {
927                 /* mkdir .snap/foo is a MKSNAP */
928                 op = CEPH_MDS_OP_MKSNAP;
929                 dout("mksnap dir %p snap '%pd' dn %p\n", dir,
930                      dentry, dentry);
931         } else if (ceph_snap(dir) == CEPH_NOSNAP) {
932                 dout("mkdir dir %p dn %p mode 0%ho\n", dir, dentry, mode);
933                 op = CEPH_MDS_OP_MKDIR;
934         } else {
935                 goto out;
936         }
937 
938         if (op == CEPH_MDS_OP_MKDIR &&
939             ceph_quota_is_max_files_exceeded(dir)) {
940                 err = -EDQUOT;
941                 goto out;
942         }
943 
944         mode |= S_IFDIR;
945         err = ceph_pre_init_acls(dir, &mode, &acls);
946         if (err < 0)
947                 goto out;
948 
949         req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
950         if (IS_ERR(req)) {
951                 err = PTR_ERR(req);
952                 goto out;
953         }
954 
955         req->r_dentry = dget(dentry);
956         req->r_num_caps = 2;
957         req->r_parent = dir;
958         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
959         req->r_args.mkdir.mode = cpu_to_le32(mode);
960         req->r_dentry_drop = CEPH_CAP_FILE_SHARED | CEPH_CAP_AUTH_EXCL;
961         req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
962         if (acls.pagelist) {
963                 req->r_pagelist = acls.pagelist;
964                 acls.pagelist = NULL;
965         }
966         err = ceph_mdsc_do_request(mdsc, dir, req);
967         if (!err &&
968             !req->r_reply_info.head->is_target &&
969             !req->r_reply_info.head->is_dentry)
970                 err = ceph_handle_notrace_create(dir, dentry);
971         ceph_mdsc_put_request(req);
972 out:
973         if (!err)
974                 ceph_init_inode_acls(d_inode(dentry), &acls);
975         else
976                 d_drop(dentry);
977         ceph_release_acls_info(&acls);
978         return err;
979 }
980 
981 static int ceph_link(struct dentry *old_dentry, struct inode *dir,
982                      struct dentry *dentry)
983 {
984         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
985         struct ceph_mds_client *mdsc = fsc->mdsc;
986         struct ceph_mds_request *req;
987         int err;
988 
989         if (ceph_snap(dir) != CEPH_NOSNAP)
990                 return -EROFS;
991 
992         dout("link in dir %p old_dentry %p dentry %p\n", dir,
993              old_dentry, dentry);
994         req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LINK, USE_AUTH_MDS);
995         if (IS_ERR(req)) {
996                 d_drop(dentry);
997                 return PTR_ERR(req);
998         }
999         req->r_dentry = dget(dentry);
1000         req->r_num_caps = 2;
1001         req->r_old_dentry = dget(old_dentry);
1002         req->r_parent = dir;
1003         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
1004         req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
1005         req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
1006         /* release LINK_SHARED on source inode (mds will lock it) */
1007         req->r_old_inode_drop = CEPH_CAP_LINK_SHARED | CEPH_CAP_LINK_EXCL;
1008         err = ceph_mdsc_do_request(mdsc, dir, req);
1009         if (err) {
1010                 d_drop(dentry);
1011         } else if (!req->r_reply_info.head->is_dentry) {
1012                 ihold(d_inode(old_dentry));
1013                 d_instantiate(dentry, d_inode(old_dentry));
1014         }
1015         ceph_mdsc_put_request(req);
1016         return err;
1017 }
1018 
1019 /*
1020  * rmdir and unlink are differ only by the metadata op code
1021  */
1022 static int ceph_unlink(struct inode *dir, struct dentry *dentry)
1023 {
1024         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
1025         struct ceph_mds_client *mdsc = fsc->mdsc;
1026         struct inode *inode = d_inode(dentry);
1027         struct ceph_mds_request *req;
1028         int err = -EROFS;
1029         int op;
1030 
1031         if (ceph_snap(dir) == CEPH_SNAPDIR) {
1032                 /* rmdir .snap/foo is RMSNAP */
1033                 dout("rmsnap dir %p '%pd' dn %p\n", dir, dentry, dentry);
1034                 op = CEPH_MDS_OP_RMSNAP;
1035         } else if (ceph_snap(dir) == CEPH_NOSNAP) {
1036                 dout("unlink/rmdir dir %p dn %p inode %p\n",
1037                      dir, dentry, inode);
1038                 op = d_is_dir(dentry) ?
1039                         CEPH_MDS_OP_RMDIR : CEPH_MDS_OP_UNLINK;
1040         } else
1041                 goto out;
1042         req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
1043         if (IS_ERR(req)) {
1044                 err = PTR_ERR(req);
1045                 goto out;
1046         }
1047         req->r_dentry = dget(dentry);
1048         req->r_num_caps = 2;
1049         req->r_parent = dir;
1050         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
1051         req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
1052         req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
1053         req->r_inode_drop = ceph_drop_caps_for_unlink(inode);
1054         err = ceph_mdsc_do_request(mdsc, dir, req);
1055         if (!err && !req->r_reply_info.head->is_dentry)
1056                 d_delete(dentry);
1057         ceph_mdsc_put_request(req);
1058 out:
1059         return err;
1060 }
1061 
1062 static int ceph_rename(struct inode *old_dir, struct dentry *old_dentry,
1063                        struct inode *new_dir, struct dentry *new_dentry,
1064                        unsigned int flags)
1065 {
1066         struct ceph_fs_client *fsc = ceph_sb_to_client(old_dir->i_sb);
1067         struct ceph_mds_client *mdsc = fsc->mdsc;
1068         struct ceph_mds_request *req;
1069         int op = CEPH_MDS_OP_RENAME;
1070         int err;
1071 
1072         if (flags)
1073                 return -EINVAL;
1074 
1075         if (ceph_snap(old_dir) != ceph_snap(new_dir))
1076                 return -EXDEV;
1077         if (ceph_snap(old_dir) != CEPH_NOSNAP) {
1078                 if (old_dir == new_dir && ceph_snap(old_dir) == CEPH_SNAPDIR)
1079                         op = CEPH_MDS_OP_RENAMESNAP;
1080                 else
1081                         return -EROFS;
1082         }
1083         /* don't allow cross-quota renames */
1084         if ((old_dir != new_dir) &&
1085             (!ceph_quota_is_same_realm(old_dir, new_dir)))
1086                 return -EXDEV;
1087 
1088         dout("rename dir %p dentry %p to dir %p dentry %p\n",
1089              old_dir, old_dentry, new_dir, new_dentry);
1090         req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
1091         if (IS_ERR(req))
1092                 return PTR_ERR(req);
1093         ihold(old_dir);
1094         req->r_dentry = dget(new_dentry);
1095         req->r_num_caps = 2;
1096         req->r_old_dentry = dget(old_dentry);
1097         req->r_old_dentry_dir = old_dir;
1098         req->r_parent = new_dir;
1099         set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
1100         req->r_old_dentry_drop = CEPH_CAP_FILE_SHARED;
1101         req->r_old_dentry_unless = CEPH_CAP_FILE_EXCL;
1102         req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
1103         req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
1104         /* release LINK_RDCACHE on source inode (mds will lock it) */
1105         req->r_old_inode_drop = CEPH_CAP_LINK_SHARED | CEPH_CAP_LINK_EXCL;
1106         if (d_really_is_positive(new_dentry)) {
1107                 req->r_inode_drop =
1108                         ceph_drop_caps_for_unlink(d_inode(new_dentry));
1109         }
1110         err = ceph_mdsc_do_request(mdsc, old_dir, req);
1111         if (!err && !req->r_reply_info.head->is_dentry) {
1112                 /*
1113                  * Normally d_move() is done by fill_trace (called by
1114                  * do_request, above).  If there is no trace, we need
1115                  * to do it here.
1116                  */
1117                 d_move(old_dentry, new_dentry);
1118         }
1119         ceph_mdsc_put_request(req);
1120         return err;
1121 }
1122 
1123 /*
1124  * Ensure a dentry lease will no longer revalidate.
1125  */
1126 void ceph_invalidate_dentry_lease(struct dentry *dentry)
1127 {
1128         spin_lock(&dentry->d_lock);
1129         ceph_dentry(dentry)->time = jiffies;
1130         ceph_dentry(dentry)->lease_shared_gen = 0;
1131         spin_unlock(&dentry->d_lock);
1132 }
1133 
1134 /*
1135  * Check if dentry lease is valid.  If not, delete the lease.  Try to
1136  * renew if the least is more than half up.
1137  */
1138 static int dentry_lease_is_valid(struct dentry *dentry, unsigned int flags,
1139                                  struct inode *dir)
1140 {
1141         struct ceph_dentry_info *di;
1142         struct ceph_mds_session *s;
1143         int valid = 0;
1144         u32 gen;
1145         unsigned long ttl;
1146         struct ceph_mds_session *session = NULL;
1147         u32 seq = 0;
1148 
1149         spin_lock(&dentry->d_lock);
1150         di = ceph_dentry(dentry);
1151         if (di && di->lease_session) {
1152                 s = di->lease_session;
1153                 spin_lock(&s->s_gen_ttl_lock);
1154                 gen = s->s_cap_gen;
1155                 ttl = s->s_cap_ttl;
1156                 spin_unlock(&s->s_gen_ttl_lock);
1157 
1158                 if (di->lease_gen == gen &&
1159                     time_before(jiffies, di->time) &&
1160                     time_before(jiffies, ttl)) {
1161                         valid = 1;
1162                         if (di->lease_renew_after &&
1163                             time_after(jiffies, di->lease_renew_after)) {
1164                                 /*
1165                                  * We should renew. If we're in RCU walk mode
1166                                  * though, we can't do that so just return
1167                                  * -ECHILD.
1168                                  */
1169                                 if (flags & LOOKUP_RCU) {
1170                                         valid = -ECHILD;
1171                                 } else {
1172                                         session = ceph_get_mds_session(s);
1173                                         seq = di->lease_seq;
1174                                         di->lease_renew_after = 0;
1175                                         di->lease_renew_from = jiffies;
1176                                 }
1177                         }
1178                 }
1179         }
1180         spin_unlock(&dentry->d_lock);
1181 
1182         if (session) {
1183                 ceph_mdsc_lease_send_msg(session, dir, dentry,
1184                                          CEPH_MDS_LEASE_RENEW, seq);
1185                 ceph_put_mds_session(session);
1186         }
1187         dout("dentry_lease_is_valid - dentry %p = %d\n", dentry, valid);
1188         return valid;
1189 }
1190 
1191 /*
1192  * Check if directory-wide content lease/cap is valid.
1193  */
1194 static int dir_lease_is_valid(struct inode *dir, struct dentry *dentry)
1195 {
1196         struct ceph_inode_info *ci = ceph_inode(dir);
1197         struct ceph_dentry_info *di = ceph_dentry(dentry);
1198         int valid = 0;
1199 
1200         spin_lock(&ci->i_ceph_lock);
1201         if (atomic_read(&ci->i_shared_gen) == di->lease_shared_gen)
1202                 valid = __ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1);
1203         spin_unlock(&ci->i_ceph_lock);
1204         dout("dir_lease_is_valid dir %p v%u dentry %p v%u = %d\n",
1205              dir, (unsigned)atomic_read(&ci->i_shared_gen),
1206              dentry, (unsigned)di->lease_shared_gen, valid);
1207         return valid;
1208 }
1209 
1210 /*
1211  * Check if cached dentry can be trusted.
1212  */
1213 static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
1214 {
1215         int valid = 0;
1216         struct dentry *parent;
1217         struct inode *dir;
1218 
1219         if (flags & LOOKUP_RCU) {
1220                 parent = READ_ONCE(dentry->d_parent);
1221                 dir = d_inode_rcu(parent);
1222                 if (!dir)
1223                         return -ECHILD;
1224         } else {
1225                 parent = dget_parent(dentry);
1226                 dir = d_inode(parent);
1227         }
1228 
1229         dout("d_revalidate %p '%pd' inode %p offset %lld\n", dentry,
1230              dentry, d_inode(dentry), ceph_dentry(dentry)->offset);
1231 
1232         /* always trust cached snapped dentries, snapdir dentry */
1233         if (ceph_snap(dir) != CEPH_NOSNAP) {
1234                 dout("d_revalidate %p '%pd' inode %p is SNAPPED\n", dentry,
1235                      dentry, d_inode(dentry));
1236                 valid = 1;
1237         } else if (d_really_is_positive(dentry) &&
1238                    ceph_snap(d_inode(dentry)) == CEPH_SNAPDIR) {
1239                 valid = 1;
1240         } else {
1241                 valid = dentry_lease_is_valid(dentry, flags, dir);
1242                 if (valid == -ECHILD)
1243                         return valid;
1244                 if (valid || dir_lease_is_valid(dir, dentry)) {
1245                         if (d_really_is_positive(dentry))
1246                                 valid = ceph_is_any_caps(d_inode(dentry));
1247                         else
1248                                 valid = 1;
1249                 }
1250         }
1251 
1252         if (!valid) {
1253                 struct ceph_mds_client *mdsc =
1254                         ceph_sb_to_client(dir->i_sb)->mdsc;
1255                 struct ceph_mds_request *req;
1256                 int op, err;
1257                 u32 mask;
1258 
1259                 if (flags & LOOKUP_RCU)
1260                         return -ECHILD;
1261 
1262                 op = ceph_snap(dir) == CEPH_SNAPDIR ?
1263                         CEPH_MDS_OP_LOOKUPSNAP : CEPH_MDS_OP_LOOKUP;
1264                 req = ceph_mdsc_create_request(mdsc, op, USE_ANY_MDS);
1265                 if (!IS_ERR(req)) {
1266                         req->r_dentry = dget(dentry);
1267                         req->r_num_caps = 2;
1268                         req->r_parent = dir;
1269 
1270                         mask = CEPH_STAT_CAP_INODE | CEPH_CAP_AUTH_SHARED;
1271                         if (ceph_security_xattr_wanted(dir))
1272                                 mask |= CEPH_CAP_XATTR_SHARED;
1273                         req->r_args.getattr.mask = cpu_to_le32(mask);
1274 
1275                         err = ceph_mdsc_do_request(mdsc, NULL, req);
1276                         switch (err) {
1277                         case 0:
1278                                 if (d_really_is_positive(dentry) &&
1279                                     d_inode(dentry) == req->r_target_inode)
1280                                         valid = 1;
1281                                 break;
1282                         case -ENOENT:
1283                                 if (d_really_is_negative(dentry))
1284                                         valid = 1;
1285                                 /* Fallthrough */
1286                         default:
1287                                 break;
1288                         }
1289                         ceph_mdsc_put_request(req);
1290                         dout("d_revalidate %p lookup result=%d\n",
1291                              dentry, err);
1292                 }
1293         }
1294 
1295         dout("d_revalidate %p %s\n", dentry, valid ? "valid" : "invalid");
1296         if (valid) {
1297                 ceph_dentry_lru_touch(dentry);
1298         } else {
1299                 ceph_dir_clear_complete(dir);
1300         }
1301 
1302         if (!(flags & LOOKUP_RCU))
1303                 dput(parent);
1304         return valid;
1305 }
1306 
1307 /*
1308  * Release our ceph_dentry_info.
1309  */
1310 static void ceph_d_release(struct dentry *dentry)
1311 {
1312         struct ceph_dentry_info *di = ceph_dentry(dentry);
1313 
1314         dout("d_release %p\n", dentry);
1315         ceph_dentry_lru_del(dentry);
1316 
1317         spin_lock(&dentry->d_lock);
1318         dentry->d_fsdata = NULL;
1319         spin_unlock(&dentry->d_lock);
1320 
1321         if (di->lease_session)
1322                 ceph_put_mds_session(di->lease_session);
1323         kmem_cache_free(ceph_dentry_cachep, di);
1324 }
1325 
1326 /*
1327  * When the VFS prunes a dentry from the cache, we need to clear the
1328  * complete flag on the parent directory.
1329  *
1330  * Called under dentry->d_lock.
1331  */
1332 static void ceph_d_prune(struct dentry *dentry)
1333 {
1334         struct ceph_inode_info *dir_ci;
1335         struct ceph_dentry_info *di;
1336 
1337         dout("ceph_d_prune %pd %p\n", dentry, dentry);
1338 
1339         /* do we have a valid parent? */
1340         if (IS_ROOT(dentry))
1341                 return;
1342 
1343         /* we hold d_lock, so d_parent is stable */
1344         dir_ci = ceph_inode(d_inode(dentry->d_parent));
1345         if (dir_ci->i_vino.snap == CEPH_SNAPDIR)
1346                 return;
1347 
1348         /* who calls d_delete() should also disable dcache readdir */
1349         if (d_really_is_negative(dentry))
1350                 return;
1351 
1352         /* d_fsdata does not get cleared until d_release */
1353         if (!d_unhashed(dentry)) {
1354                 __ceph_dir_clear_complete(dir_ci);
1355                 return;
1356         }
1357 
1358         /* Disable dcache readdir just in case that someone called d_drop()
1359          * or d_invalidate(), but MDS didn't revoke CEPH_CAP_FILE_SHARED
1360          * properly (dcache readdir is still enabled) */
1361         di = ceph_dentry(dentry);
1362         if (di->offset > 0 &&
1363             di->lease_shared_gen == atomic_read(&dir_ci->i_shared_gen))
1364                 __ceph_dir_clear_ordered(dir_ci);
1365 }
1366 
1367 /*
1368  * read() on a dir.  This weird interface hack only works if mounted
1369  * with '-o dirstat'.
1370  */
1371 static ssize_t ceph_read_dir(struct file *file, char __user *buf, size_t size,
1372                              loff_t *ppos)
1373 {
1374         struct ceph_dir_file_info *dfi = file->private_data;
1375         struct inode *inode = file_inode(file);
1376         struct ceph_inode_info *ci = ceph_inode(inode);
1377         int left;
1378         const int bufsize = 1024;
1379 
1380         if (!ceph_test_mount_opt(ceph_sb_to_client(inode->i_sb), DIRSTAT))
1381                 return -EISDIR;
1382 
1383         if (!dfi->dir_info) {
1384                 dfi->dir_info = kmalloc(bufsize, GFP_KERNEL);
1385                 if (!dfi->dir_info)
1386                         return -ENOMEM;
1387                 dfi->dir_info_len =
1388                         snprintf(dfi->dir_info, bufsize,
1389                                 "entries:   %20lld\n"
1390                                 " files:    %20lld\n"
1391                                 " subdirs:  %20lld\n"
1392                                 "rentries:  %20lld\n"
1393                                 " rfiles:   %20lld\n"
1394                                 " rsubdirs: %20lld\n"
1395                                 "rbytes:    %20lld\n"
1396                                 "rctime:    %10ld.%09ld\n",
1397                                 ci->i_files + ci->i_subdirs,
1398                                 ci->i_files,
1399                                 ci->i_subdirs,
1400                                 ci->i_rfiles + ci->i_rsubdirs,
1401                                 ci->i_rfiles,
1402                                 ci->i_rsubdirs,
1403                                 ci->i_rbytes,
1404                                 (long)ci->i_rctime.tv_sec,
1405                                 (long)ci->i_rctime.tv_nsec);
1406         }
1407 
1408         if (*ppos >= dfi->dir_info_len)
1409                 return 0;
1410         size = min_t(unsigned, size, dfi->dir_info_len-*ppos);
1411         left = copy_to_user(buf, dfi->dir_info + *ppos, size);
1412         if (left == size)
1413                 return -EFAULT;
1414         *ppos += (size - left);
1415         return size - left;
1416 }
1417 
1418 /*
1419  * We maintain a private dentry LRU.
1420  *
1421  * FIXME: this needs to be changed to a per-mds lru to be useful.
1422  */
1423 void ceph_dentry_lru_add(struct dentry *dn)
1424 {
1425         struct ceph_dentry_info *di = ceph_dentry(dn);
1426         struct ceph_mds_client *mdsc;
1427 
1428         dout("dentry_lru_add %p %p '%pd'\n", di, dn, dn);
1429         mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
1430         spin_lock(&mdsc->dentry_lru_lock);
1431         list_add_tail(&di->lru, &mdsc->dentry_lru);
1432         mdsc->num_dentry++;
1433         spin_unlock(&mdsc->dentry_lru_lock);
1434 }
1435 
1436 void ceph_dentry_lru_touch(struct dentry *dn)
1437 {
1438         struct ceph_dentry_info *di = ceph_dentry(dn);
1439         struct ceph_mds_client *mdsc;
1440 
1441         dout("dentry_lru_touch %p %p '%pd' (offset %lld)\n", di, dn, dn,
1442              di->offset);
1443         mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
1444         spin_lock(&mdsc->dentry_lru_lock);
1445         list_move_tail(&di->lru, &mdsc->dentry_lru);
1446         spin_unlock(&mdsc->dentry_lru_lock);
1447 }
1448 
1449 void ceph_dentry_lru_del(struct dentry *dn)
1450 {
1451         struct ceph_dentry_info *di = ceph_dentry(dn);
1452         struct ceph_mds_client *mdsc;
1453 
1454         dout("dentry_lru_del %p %p '%pd'\n", di, dn, dn);
1455         mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
1456         spin_lock(&mdsc->dentry_lru_lock);
1457         list_del_init(&di->lru);
1458         mdsc->num_dentry--;
1459         spin_unlock(&mdsc->dentry_lru_lock);
1460 }
1461 
1462 /*
1463  * Return name hash for a given dentry.  This is dependent on
1464  * the parent directory's hash function.
1465  */
1466 unsigned ceph_dentry_hash(struct inode *dir, struct dentry *dn)
1467 {
1468         struct ceph_inode_info *dci = ceph_inode(dir);
1469 
1470         switch (dci->i_dir_layout.dl_dir_hash) {
1471         case 0: /* for backward compat */
1472         case CEPH_STR_HASH_LINUX:
1473                 return dn->d_name.hash;
1474 
1475         default:
1476                 return ceph_str_hash(dci->i_dir_layout.dl_dir_hash,
1477                                      dn->d_name.name, dn->d_name.len);
1478         }
1479 }
1480 
1481 const struct file_operations ceph_dir_fops = {
1482         .read = ceph_read_dir,
1483         .iterate = ceph_readdir,
1484         .llseek = ceph_dir_llseek,
1485         .open = ceph_open,
1486         .release = ceph_release,
1487         .unlocked_ioctl = ceph_ioctl,
1488         .fsync = ceph_fsync,
1489         .lock = ceph_lock,
1490         .flock = ceph_flock,
1491 };
1492 
1493 const struct file_operations ceph_snapdir_fops = {
1494         .iterate = ceph_readdir,
1495         .llseek = ceph_dir_llseek,
1496         .open = ceph_open,
1497         .release = ceph_release,
1498 };
1499 
1500 const struct inode_operations ceph_dir_iops = {
1501         .lookup = ceph_lookup,
1502         .permission = ceph_permission,
1503         .getattr = ceph_getattr,
1504         .setattr = ceph_setattr,
1505         .listxattr = ceph_listxattr,
1506         .get_acl = ceph_get_acl,
1507         .set_acl = ceph_set_acl,
1508         .mknod = ceph_mknod,
1509         .symlink = ceph_symlink,
1510         .mkdir = ceph_mkdir,
1511         .link = ceph_link,
1512         .unlink = ceph_unlink,
1513         .rmdir = ceph_unlink,
1514         .rename = ceph_rename,
1515         .create = ceph_create,
1516         .atomic_open = ceph_atomic_open,
1517 };
1518 
1519 const struct inode_operations ceph_snapdir_iops = {
1520         .lookup = ceph_lookup,
1521         .permission = ceph_permission,
1522         .getattr = ceph_getattr,
1523         .mkdir = ceph_mkdir,
1524         .rmdir = ceph_unlink,
1525         .rename = ceph_rename,
1526 };
1527 
1528 const struct dentry_operations ceph_dentry_ops = {
1529         .d_revalidate = ceph_d_revalidate,
1530         .d_release = ceph_d_release,
1531         .d_prune = ceph_d_prune,
1532         .d_init = ceph_d_init,
1533 };
1534 

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