xref: /linux/fs/ceph/dir.c (revision cc04a46f11ea046ed53e2c832ae29e4790f7e35f)
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 dentry_operations ceph_dentry_ops;
30 
31 /*
32  * Initialize ceph dentry state.
33  */
34 int ceph_init_dentry(struct dentry *dentry)
35 {
36 	struct ceph_dentry_info *di;
37 
38 	if (dentry->d_fsdata)
39 		return 0;
40 
41 	di = kmem_cache_alloc(ceph_dentry_cachep, GFP_KERNEL | __GFP_ZERO);
42 	if (!di)
43 		return -ENOMEM;          /* oh well */
44 
45 	spin_lock(&dentry->d_lock);
46 	if (dentry->d_fsdata) {
47 		/* lost a race */
48 		kmem_cache_free(ceph_dentry_cachep, di);
49 		goto out_unlock;
50 	}
51 
52 	if (ceph_snap(d_inode(dentry->d_parent)) == CEPH_NOSNAP)
53 		d_set_d_op(dentry, &ceph_dentry_ops);
54 	else if (ceph_snap(d_inode(dentry->d_parent)) == CEPH_SNAPDIR)
55 		d_set_d_op(dentry, &ceph_snapdir_dentry_ops);
56 	else
57 		d_set_d_op(dentry, &ceph_snap_dentry_ops);
58 
59 	di->dentry = dentry;
60 	di->lease_session = NULL;
61 	dentry->d_time = jiffies;
62 	/* avoid reordering d_fsdata setup so that the check above is safe */
63 	smp_mb();
64 	dentry->d_fsdata = di;
65 	ceph_dentry_lru_add(dentry);
66 out_unlock:
67 	spin_unlock(&dentry->d_lock);
68 	return 0;
69 }
70 
71 struct inode *ceph_get_dentry_parent_inode(struct dentry *dentry)
72 {
73 	struct inode *inode = NULL;
74 
75 	if (!dentry)
76 		return NULL;
77 
78 	spin_lock(&dentry->d_lock);
79 	if (!IS_ROOT(dentry)) {
80 		inode = d_inode(dentry->d_parent);
81 		ihold(inode);
82 	}
83 	spin_unlock(&dentry->d_lock);
84 	return inode;
85 }
86 
87 
88 /*
89  * for readdir, we encode the directory frag and offset within that
90  * frag into f_pos.
91  */
92 static unsigned fpos_frag(loff_t p)
93 {
94 	return p >> 32;
95 }
96 static unsigned fpos_off(loff_t p)
97 {
98 	return p & 0xffffffff;
99 }
100 
101 static int fpos_cmp(loff_t l, loff_t r)
102 {
103 	int v = ceph_frag_compare(fpos_frag(l), fpos_frag(r));
104 	if (v)
105 		return v;
106 	return (int)(fpos_off(l) - fpos_off(r));
107 }
108 
109 /*
110  * make note of the last dentry we read, so we can
111  * continue at the same lexicographical point,
112  * regardless of what dir changes take place on the
113  * server.
114  */
115 static int note_last_dentry(struct ceph_file_info *fi, const char *name,
116 		            int len, unsigned next_offset)
117 {
118 	char *buf = kmalloc(len+1, GFP_KERNEL);
119 	if (!buf)
120 		return -ENOMEM;
121 	kfree(fi->last_name);
122 	fi->last_name = buf;
123 	memcpy(fi->last_name, name, len);
124 	fi->last_name[len] = 0;
125 	fi->next_offset = next_offset;
126 	dout("note_last_dentry '%s'\n", fi->last_name);
127 	return 0;
128 }
129 
130 /*
131  * When possible, we try to satisfy a readdir by peeking at the
132  * dcache.  We make this work by carefully ordering dentries on
133  * d_child when we initially get results back from the MDS, and
134  * falling back to a "normal" sync readdir if any dentries in the dir
135  * are dropped.
136  *
137  * Complete dir indicates that we have all dentries in the dir.  It is
138  * defined IFF we hold CEPH_CAP_FILE_SHARED (which will be revoked by
139  * the MDS if/when the directory is modified).
140  */
141 static int __dcache_readdir(struct file *file,  struct dir_context *ctx,
142 			    u32 shared_gen)
143 {
144 	struct ceph_file_info *fi = file->private_data;
145 	struct dentry *parent = file->f_path.dentry;
146 	struct inode *dir = d_inode(parent);
147 	struct dentry *dentry, *last = NULL;
148 	struct ceph_dentry_info *di;
149 	unsigned nsize = PAGE_CACHE_SIZE / sizeof(struct dentry *);
150 	int err = 0;
151 	loff_t ptr_pos = 0;
152 	struct ceph_readdir_cache_control cache_ctl = {};
153 
154 	dout("__dcache_readdir %p v%u at %llu\n", dir, shared_gen, ctx->pos);
155 
156 	/* we can calculate cache index for the first dirfrag */
157 	if (ceph_frag_is_leftmost(fpos_frag(ctx->pos))) {
158 		cache_ctl.index = fpos_off(ctx->pos) - 2;
159 		BUG_ON(cache_ctl.index < 0);
160 		ptr_pos = cache_ctl.index * sizeof(struct dentry *);
161 	}
162 
163 	while (true) {
164 		pgoff_t pgoff;
165 		bool emit_dentry;
166 
167 		if (ptr_pos >= i_size_read(dir)) {
168 			fi->flags |= CEPH_F_ATEND;
169 			err = 0;
170 			break;
171 		}
172 
173 		err = -EAGAIN;
174 		pgoff = ptr_pos >> PAGE_CACHE_SHIFT;
175 		if (!cache_ctl.page || pgoff != page_index(cache_ctl.page)) {
176 			ceph_readdir_cache_release(&cache_ctl);
177 			cache_ctl.page = find_lock_page(&dir->i_data, pgoff);
178 			if (!cache_ctl.page) {
179 				dout(" page %lu not found\n", pgoff);
180 				break;
181 			}
182 			/* reading/filling the cache are serialized by
183 			 * i_mutex, no need to use page lock */
184 			unlock_page(cache_ctl.page);
185 			cache_ctl.dentries = kmap(cache_ctl.page);
186 		}
187 
188 		rcu_read_lock();
189 		spin_lock(&parent->d_lock);
190 		/* check i_size again here, because empty directory can be
191 		 * marked as complete while not holding the i_mutex. */
192 		if (ceph_dir_is_complete_ordered(dir) &&
193 		    ptr_pos < i_size_read(dir))
194 			dentry = cache_ctl.dentries[cache_ctl.index % nsize];
195 		else
196 			dentry = NULL;
197 		spin_unlock(&parent->d_lock);
198 		if (dentry && !lockref_get_not_dead(&dentry->d_lockref))
199 			dentry = NULL;
200 		rcu_read_unlock();
201 		if (!dentry)
202 			break;
203 
204 		emit_dentry = false;
205 		di = ceph_dentry(dentry);
206 		spin_lock(&dentry->d_lock);
207 		if (di->lease_shared_gen == shared_gen &&
208 		    d_really_is_positive(dentry) &&
209 		    ceph_snap(d_inode(dentry)) != CEPH_SNAPDIR &&
210 		    ceph_ino(d_inode(dentry)) != CEPH_INO_CEPH &&
211 		    fpos_cmp(ctx->pos, di->offset) <= 0) {
212 			emit_dentry = true;
213 		}
214 		spin_unlock(&dentry->d_lock);
215 
216 		if (emit_dentry) {
217 			dout(" %llu (%llu) dentry %p %pd %p\n", di->offset, ctx->pos,
218 			     dentry, dentry, d_inode(dentry));
219 			ctx->pos = di->offset;
220 			if (!dir_emit(ctx, dentry->d_name.name,
221 				      dentry->d_name.len,
222 				      ceph_translate_ino(dentry->d_sb,
223 							 d_inode(dentry)->i_ino),
224 				      d_inode(dentry)->i_mode >> 12)) {
225 				dput(dentry);
226 				err = 0;
227 				break;
228 			}
229 			ctx->pos++;
230 
231 			if (last)
232 				dput(last);
233 			last = dentry;
234 		} else {
235 			dput(dentry);
236 		}
237 
238 		cache_ctl.index++;
239 		ptr_pos += sizeof(struct dentry *);
240 	}
241 	ceph_readdir_cache_release(&cache_ctl);
242 	if (last) {
243 		int ret;
244 		di = ceph_dentry(last);
245 		ret = note_last_dentry(fi, last->d_name.name, last->d_name.len,
246 				       fpos_off(di->offset) + 1);
247 		if (ret < 0)
248 			err = ret;
249 		dput(last);
250 	}
251 	return err;
252 }
253 
254 static int ceph_readdir(struct file *file, struct dir_context *ctx)
255 {
256 	struct ceph_file_info *fi = file->private_data;
257 	struct inode *inode = file_inode(file);
258 	struct ceph_inode_info *ci = ceph_inode(inode);
259 	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
260 	struct ceph_mds_client *mdsc = fsc->mdsc;
261 	unsigned frag = fpos_frag(ctx->pos);
262 	int off = fpos_off(ctx->pos);
263 	int err;
264 	u32 ftype;
265 	struct ceph_mds_reply_info_parsed *rinfo;
266 
267 	dout("readdir %p file %p frag %u off %u\n", inode, file, frag, off);
268 	if (fi->flags & CEPH_F_ATEND)
269 		return 0;
270 
271 	/* always start with . and .. */
272 	if (ctx->pos == 0) {
273 		dout("readdir off 0 -> '.'\n");
274 		if (!dir_emit(ctx, ".", 1,
275 			    ceph_translate_ino(inode->i_sb, inode->i_ino),
276 			    inode->i_mode >> 12))
277 			return 0;
278 		ctx->pos = 1;
279 		off = 1;
280 	}
281 	if (ctx->pos == 1) {
282 		ino_t ino = parent_ino(file->f_path.dentry);
283 		dout("readdir off 1 -> '..'\n");
284 		if (!dir_emit(ctx, "..", 2,
285 			    ceph_translate_ino(inode->i_sb, ino),
286 			    inode->i_mode >> 12))
287 			return 0;
288 		ctx->pos = 2;
289 		off = 2;
290 	}
291 
292 	/* can we use the dcache? */
293 	spin_lock(&ci->i_ceph_lock);
294 	if (ceph_test_mount_opt(fsc, DCACHE) &&
295 	    !ceph_test_mount_opt(fsc, NOASYNCREADDIR) &&
296 	    ceph_snap(inode) != CEPH_SNAPDIR &&
297 	    __ceph_dir_is_complete_ordered(ci) &&
298 	    __ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1)) {
299 		u32 shared_gen = ci->i_shared_gen;
300 		spin_unlock(&ci->i_ceph_lock);
301 		err = __dcache_readdir(file, ctx, shared_gen);
302 		if (err != -EAGAIN)
303 			return err;
304 		frag = fpos_frag(ctx->pos);
305 		off = fpos_off(ctx->pos);
306 	} else {
307 		spin_unlock(&ci->i_ceph_lock);
308 	}
309 
310 	/* proceed with a normal readdir */
311 more:
312 	/* do we have the correct frag content buffered? */
313 	if (fi->frag != frag || fi->last_readdir == NULL) {
314 		struct ceph_mds_request *req;
315 		int op = ceph_snap(inode) == CEPH_SNAPDIR ?
316 			CEPH_MDS_OP_LSSNAP : CEPH_MDS_OP_READDIR;
317 
318 		/* discard old result, if any */
319 		if (fi->last_readdir) {
320 			ceph_mdsc_put_request(fi->last_readdir);
321 			fi->last_readdir = NULL;
322 		}
323 
324 		dout("readdir fetching %llx.%llx frag %x offset '%s'\n",
325 		     ceph_vinop(inode), frag, fi->last_name);
326 		req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
327 		if (IS_ERR(req))
328 			return PTR_ERR(req);
329 		err = ceph_alloc_readdir_reply_buffer(req, inode);
330 		if (err) {
331 			ceph_mdsc_put_request(req);
332 			return err;
333 		}
334 		/* hints to request -> mds selection code */
335 		req->r_direct_mode = USE_AUTH_MDS;
336 		req->r_direct_hash = ceph_frag_value(frag);
337 		req->r_direct_is_hash = true;
338 		if (fi->last_name) {
339 			req->r_path2 = kstrdup(fi->last_name, GFP_KERNEL);
340 			if (!req->r_path2) {
341 				ceph_mdsc_put_request(req);
342 				return -ENOMEM;
343 			}
344 		}
345 		req->r_dir_release_cnt = fi->dir_release_count;
346 		req->r_dir_ordered_cnt = fi->dir_ordered_count;
347 		req->r_readdir_cache_idx = fi->readdir_cache_idx;
348 		req->r_readdir_offset = fi->next_offset;
349 		req->r_args.readdir.frag = cpu_to_le32(frag);
350 
351 		req->r_inode = inode;
352 		ihold(inode);
353 		req->r_dentry = dget(file->f_path.dentry);
354 		err = ceph_mdsc_do_request(mdsc, NULL, req);
355 		if (err < 0) {
356 			ceph_mdsc_put_request(req);
357 			return err;
358 		}
359 		dout("readdir got and parsed readdir result=%d"
360 		     " on frag %x, end=%d, complete=%d\n", err, frag,
361 		     (int)req->r_reply_info.dir_end,
362 		     (int)req->r_reply_info.dir_complete);
363 
364 
365 		/* note next offset and last dentry name */
366 		rinfo = &req->r_reply_info;
367 		if (le32_to_cpu(rinfo->dir_dir->frag) != frag) {
368 			frag = le32_to_cpu(rinfo->dir_dir->frag);
369 			off = req->r_readdir_offset;
370 			fi->next_offset = off;
371 		}
372 
373 		fi->frag = frag;
374 		fi->offset = fi->next_offset;
375 		fi->last_readdir = req;
376 
377 		if (req->r_did_prepopulate) {
378 			fi->readdir_cache_idx = req->r_readdir_cache_idx;
379 			if (fi->readdir_cache_idx < 0) {
380 				/* preclude from marking dir ordered */
381 				fi->dir_ordered_count = 0;
382 			} else if (ceph_frag_is_leftmost(frag) && off == 2) {
383 				/* note dir version at start of readdir so
384 				 * we can tell if any dentries get dropped */
385 				fi->dir_release_count = req->r_dir_release_cnt;
386 				fi->dir_ordered_count = req->r_dir_ordered_cnt;
387 			}
388 		} else {
389 			dout("readdir !did_prepopulate");
390 			/* disable readdir cache */
391 			fi->readdir_cache_idx = -1;
392 			/* preclude from marking dir complete */
393 			fi->dir_release_count = 0;
394 		}
395 
396 		if (req->r_reply_info.dir_end) {
397 			kfree(fi->last_name);
398 			fi->last_name = NULL;
399 			if (ceph_frag_is_rightmost(frag))
400 				fi->next_offset = 2;
401 			else
402 				fi->next_offset = 0;
403 		} else {
404 			err = note_last_dentry(fi,
405 				       rinfo->dir_dname[rinfo->dir_nr-1],
406 				       rinfo->dir_dname_len[rinfo->dir_nr-1],
407 				       fi->next_offset + rinfo->dir_nr);
408 			if (err)
409 				return err;
410 		}
411 	}
412 
413 	rinfo = &fi->last_readdir->r_reply_info;
414 	dout("readdir frag %x num %d off %d chunkoff %d\n", frag,
415 	     rinfo->dir_nr, off, fi->offset);
416 
417 	ctx->pos = ceph_make_fpos(frag, off);
418 	while (off >= fi->offset && off - fi->offset < rinfo->dir_nr) {
419 		struct ceph_mds_reply_inode *in =
420 			rinfo->dir_in[off - fi->offset].in;
421 		struct ceph_vino vino;
422 		ino_t ino;
423 
424 		dout("readdir off %d (%d/%d) -> %lld '%.*s' %p\n",
425 		     off, off - fi->offset, rinfo->dir_nr, ctx->pos,
426 		     rinfo->dir_dname_len[off - fi->offset],
427 		     rinfo->dir_dname[off - fi->offset], in);
428 		BUG_ON(!in);
429 		ftype = le32_to_cpu(in->mode) >> 12;
430 		vino.ino = le64_to_cpu(in->ino);
431 		vino.snap = le64_to_cpu(in->snapid);
432 		ino = ceph_vino_to_ino(vino);
433 		if (!dir_emit(ctx,
434 			    rinfo->dir_dname[off - fi->offset],
435 			    rinfo->dir_dname_len[off - fi->offset],
436 			    ceph_translate_ino(inode->i_sb, ino), ftype)) {
437 			dout("filldir stopping us...\n");
438 			return 0;
439 		}
440 		off++;
441 		ctx->pos++;
442 	}
443 
444 	if (fi->last_name) {
445 		ceph_mdsc_put_request(fi->last_readdir);
446 		fi->last_readdir = NULL;
447 		goto more;
448 	}
449 
450 	/* more frags? */
451 	if (!ceph_frag_is_rightmost(frag)) {
452 		frag = ceph_frag_next(frag);
453 		off = 0;
454 		ctx->pos = ceph_make_fpos(frag, off);
455 		dout("readdir next frag is %x\n", frag);
456 		goto more;
457 	}
458 	fi->flags |= CEPH_F_ATEND;
459 
460 	/*
461 	 * if dir_release_count still matches the dir, no dentries
462 	 * were released during the whole readdir, and we should have
463 	 * the complete dir contents in our cache.
464 	 */
465 	if (atomic64_read(&ci->i_release_count) == fi->dir_release_count) {
466 		spin_lock(&ci->i_ceph_lock);
467 		if (fi->dir_ordered_count == atomic64_read(&ci->i_ordered_count)) {
468 			dout(" marking %p complete and ordered\n", inode);
469 			/* use i_size to track number of entries in
470 			 * readdir cache */
471 			BUG_ON(fi->readdir_cache_idx < 0);
472 			i_size_write(inode, fi->readdir_cache_idx *
473 				     sizeof(struct dentry*));
474 		} else {
475 			dout(" marking %p complete\n", inode);
476 		}
477 		__ceph_dir_set_complete(ci, fi->dir_release_count,
478 					fi->dir_ordered_count);
479 		spin_unlock(&ci->i_ceph_lock);
480 	}
481 
482 	dout("readdir %p file %p done.\n", inode, file);
483 	return 0;
484 }
485 
486 static void reset_readdir(struct ceph_file_info *fi, unsigned frag)
487 {
488 	if (fi->last_readdir) {
489 		ceph_mdsc_put_request(fi->last_readdir);
490 		fi->last_readdir = NULL;
491 	}
492 	kfree(fi->last_name);
493 	fi->last_name = NULL;
494 	fi->dir_release_count = 0;
495 	fi->readdir_cache_idx = -1;
496 	if (ceph_frag_is_leftmost(frag))
497 		fi->next_offset = 2;  /* compensate for . and .. */
498 	else
499 		fi->next_offset = 0;
500 	fi->flags &= ~CEPH_F_ATEND;
501 }
502 
503 static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
504 {
505 	struct ceph_file_info *fi = file->private_data;
506 	struct inode *inode = file->f_mapping->host;
507 	loff_t old_offset = ceph_make_fpos(fi->frag, fi->next_offset);
508 	loff_t retval;
509 
510 	mutex_lock(&inode->i_mutex);
511 	retval = -EINVAL;
512 	switch (whence) {
513 	case SEEK_CUR:
514 		offset += file->f_pos;
515 	case SEEK_SET:
516 		break;
517 	case SEEK_END:
518 		retval = -EOPNOTSUPP;
519 	default:
520 		goto out;
521 	}
522 
523 	if (offset >= 0) {
524 		if (offset != file->f_pos) {
525 			file->f_pos = offset;
526 			file->f_version = 0;
527 			fi->flags &= ~CEPH_F_ATEND;
528 		}
529 		retval = offset;
530 
531 		if (offset == 0 ||
532 		    fpos_frag(offset) != fi->frag ||
533 		    fpos_off(offset) < fi->offset) {
534 			/* discard buffered readdir content on seekdir(0), or
535 			 * seek to new frag, or seek prior to current chunk */
536 			dout("dir_llseek dropping %p content\n", file);
537 			reset_readdir(fi, fpos_frag(offset));
538 		} else if (fpos_cmp(offset, old_offset) > 0) {
539 			/* reset dir_release_count if we did a forward seek */
540 			fi->dir_release_count = 0;
541 			fi->readdir_cache_idx = -1;
542 		}
543 	}
544 out:
545 	mutex_unlock(&inode->i_mutex);
546 	return retval;
547 }
548 
549 /*
550  * Handle lookups for the hidden .snap directory.
551  */
552 int ceph_handle_snapdir(struct ceph_mds_request *req,
553 			struct dentry *dentry, int err)
554 {
555 	struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
556 	struct inode *parent = d_inode(dentry->d_parent); /* we hold i_mutex */
557 
558 	/* .snap dir? */
559 	if (err == -ENOENT &&
560 	    ceph_snap(parent) == CEPH_NOSNAP &&
561 	    strcmp(dentry->d_name.name,
562 		   fsc->mount_options->snapdir_name) == 0) {
563 		struct inode *inode = ceph_get_snapdir(parent);
564 		dout("ENOENT on snapdir %p '%pd', linking to snapdir %p\n",
565 		     dentry, dentry, inode);
566 		BUG_ON(!d_unhashed(dentry));
567 		d_add(dentry, inode);
568 		err = 0;
569 	}
570 	return err;
571 }
572 
573 /*
574  * Figure out final result of a lookup/open request.
575  *
576  * Mainly, make sure we return the final req->r_dentry (if it already
577  * existed) in place of the original VFS-provided dentry when they
578  * differ.
579  *
580  * Gracefully handle the case where the MDS replies with -ENOENT and
581  * no trace (which it may do, at its discretion, e.g., if it doesn't
582  * care to issue a lease on the negative dentry).
583  */
584 struct dentry *ceph_finish_lookup(struct ceph_mds_request *req,
585 				  struct dentry *dentry, int err)
586 {
587 	if (err == -ENOENT) {
588 		/* no trace? */
589 		err = 0;
590 		if (!req->r_reply_info.head->is_dentry) {
591 			dout("ENOENT and no trace, dentry %p inode %p\n",
592 			     dentry, d_inode(dentry));
593 			if (d_really_is_positive(dentry)) {
594 				d_drop(dentry);
595 				err = -ENOENT;
596 			} else {
597 				d_add(dentry, NULL);
598 			}
599 		}
600 	}
601 	if (err)
602 		dentry = ERR_PTR(err);
603 	else if (dentry != req->r_dentry)
604 		dentry = dget(req->r_dentry);   /* we got spliced */
605 	else
606 		dentry = NULL;
607 	return dentry;
608 }
609 
610 static int is_root_ceph_dentry(struct inode *inode, struct dentry *dentry)
611 {
612 	return ceph_ino(inode) == CEPH_INO_ROOT &&
613 		strncmp(dentry->d_name.name, ".ceph", 5) == 0;
614 }
615 
616 /*
617  * Look up a single dir entry.  If there is a lookup intent, inform
618  * the MDS so that it gets our 'caps wanted' value in a single op.
619  */
620 static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
621 				  unsigned int flags)
622 {
623 	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
624 	struct ceph_mds_client *mdsc = fsc->mdsc;
625 	struct ceph_mds_request *req;
626 	int op;
627 	int err;
628 
629 	dout("lookup %p dentry %p '%pd'\n",
630 	     dir, dentry, dentry);
631 
632 	if (dentry->d_name.len > NAME_MAX)
633 		return ERR_PTR(-ENAMETOOLONG);
634 
635 	err = ceph_init_dentry(dentry);
636 	if (err < 0)
637 		return ERR_PTR(err);
638 
639 	/* can we conclude ENOENT locally? */
640 	if (d_really_is_negative(dentry)) {
641 		struct ceph_inode_info *ci = ceph_inode(dir);
642 		struct ceph_dentry_info *di = ceph_dentry(dentry);
643 
644 		spin_lock(&ci->i_ceph_lock);
645 		dout(" dir %p flags are %d\n", dir, ci->i_ceph_flags);
646 		if (strncmp(dentry->d_name.name,
647 			    fsc->mount_options->snapdir_name,
648 			    dentry->d_name.len) &&
649 		    !is_root_ceph_dentry(dir, dentry) &&
650 		    ceph_test_mount_opt(fsc, DCACHE) &&
651 		    __ceph_dir_is_complete(ci) &&
652 		    (__ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1))) {
653 			spin_unlock(&ci->i_ceph_lock);
654 			dout(" dir %p complete, -ENOENT\n", dir);
655 			d_add(dentry, NULL);
656 			di->lease_shared_gen = ci->i_shared_gen;
657 			return NULL;
658 		}
659 		spin_unlock(&ci->i_ceph_lock);
660 	}
661 
662 	op = ceph_snap(dir) == CEPH_SNAPDIR ?
663 		CEPH_MDS_OP_LOOKUPSNAP : CEPH_MDS_OP_LOOKUP;
664 	req = ceph_mdsc_create_request(mdsc, op, USE_ANY_MDS);
665 	if (IS_ERR(req))
666 		return ERR_CAST(req);
667 	req->r_dentry = dget(dentry);
668 	req->r_num_caps = 2;
669 	/* we only need inode linkage */
670 	req->r_args.getattr.mask = cpu_to_le32(CEPH_STAT_CAP_INODE);
671 	req->r_locked_dir = dir;
672 	err = ceph_mdsc_do_request(mdsc, NULL, req);
673 	err = ceph_handle_snapdir(req, dentry, err);
674 	dentry = ceph_finish_lookup(req, dentry, err);
675 	ceph_mdsc_put_request(req);  /* will dput(dentry) */
676 	dout("lookup result=%p\n", dentry);
677 	return dentry;
678 }
679 
680 /*
681  * If we do a create but get no trace back from the MDS, follow up with
682  * a lookup (the VFS expects us to link up the provided dentry).
683  */
684 int ceph_handle_notrace_create(struct inode *dir, struct dentry *dentry)
685 {
686 	struct dentry *result = ceph_lookup(dir, dentry, 0);
687 
688 	if (result && !IS_ERR(result)) {
689 		/*
690 		 * We created the item, then did a lookup, and found
691 		 * it was already linked to another inode we already
692 		 * had in our cache (and thus got spliced). To not
693 		 * confuse VFS (especially when inode is a directory),
694 		 * we don't link our dentry to that inode, return an
695 		 * error instead.
696 		 *
697 		 * This event should be rare and it happens only when
698 		 * we talk to old MDS. Recent MDS does not send traceless
699 		 * reply for request that creates new inode.
700 		 */
701 		d_drop(result);
702 		return -ESTALE;
703 	}
704 	return PTR_ERR(result);
705 }
706 
707 static int ceph_mknod(struct inode *dir, struct dentry *dentry,
708 		      umode_t mode, dev_t rdev)
709 {
710 	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
711 	struct ceph_mds_client *mdsc = fsc->mdsc;
712 	struct ceph_mds_request *req;
713 	struct ceph_acls_info acls = {};
714 	int err;
715 
716 	if (ceph_snap(dir) != CEPH_NOSNAP)
717 		return -EROFS;
718 
719 	err = ceph_pre_init_acls(dir, &mode, &acls);
720 	if (err < 0)
721 		return err;
722 
723 	dout("mknod in dir %p dentry %p mode 0%ho rdev %d\n",
724 	     dir, dentry, mode, rdev);
725 	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_MKNOD, USE_AUTH_MDS);
726 	if (IS_ERR(req)) {
727 		err = PTR_ERR(req);
728 		goto out;
729 	}
730 	req->r_dentry = dget(dentry);
731 	req->r_num_caps = 2;
732 	req->r_locked_dir = dir;
733 	req->r_args.mknod.mode = cpu_to_le32(mode);
734 	req->r_args.mknod.rdev = cpu_to_le32(rdev);
735 	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
736 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
737 	if (acls.pagelist) {
738 		req->r_pagelist = acls.pagelist;
739 		acls.pagelist = NULL;
740 	}
741 	err = ceph_mdsc_do_request(mdsc, dir, req);
742 	if (!err && !req->r_reply_info.head->is_dentry)
743 		err = ceph_handle_notrace_create(dir, dentry);
744 	ceph_mdsc_put_request(req);
745 out:
746 	if (!err)
747 		ceph_init_inode_acls(d_inode(dentry), &acls);
748 	else
749 		d_drop(dentry);
750 	ceph_release_acls_info(&acls);
751 	return err;
752 }
753 
754 static int ceph_create(struct inode *dir, struct dentry *dentry, umode_t mode,
755 		       bool excl)
756 {
757 	return ceph_mknod(dir, dentry, mode, 0);
758 }
759 
760 static int ceph_symlink(struct inode *dir, struct dentry *dentry,
761 			    const char *dest)
762 {
763 	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
764 	struct ceph_mds_client *mdsc = fsc->mdsc;
765 	struct ceph_mds_request *req;
766 	int err;
767 
768 	if (ceph_snap(dir) != CEPH_NOSNAP)
769 		return -EROFS;
770 
771 	dout("symlink in dir %p dentry %p to '%s'\n", dir, dentry, dest);
772 	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SYMLINK, USE_AUTH_MDS);
773 	if (IS_ERR(req)) {
774 		err = PTR_ERR(req);
775 		goto out;
776 	}
777 	req->r_path2 = kstrdup(dest, GFP_KERNEL);
778 	if (!req->r_path2) {
779 		err = -ENOMEM;
780 		ceph_mdsc_put_request(req);
781 		goto out;
782 	}
783 	req->r_locked_dir = dir;
784 	req->r_dentry = dget(dentry);
785 	req->r_num_caps = 2;
786 	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
787 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
788 	err = ceph_mdsc_do_request(mdsc, dir, req);
789 	if (!err && !req->r_reply_info.head->is_dentry)
790 		err = ceph_handle_notrace_create(dir, dentry);
791 	ceph_mdsc_put_request(req);
792 out:
793 	if (err)
794 		d_drop(dentry);
795 	return err;
796 }
797 
798 static int ceph_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
799 {
800 	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
801 	struct ceph_mds_client *mdsc = fsc->mdsc;
802 	struct ceph_mds_request *req;
803 	struct ceph_acls_info acls = {};
804 	int err = -EROFS;
805 	int op;
806 
807 	if (ceph_snap(dir) == CEPH_SNAPDIR) {
808 		/* mkdir .snap/foo is a MKSNAP */
809 		op = CEPH_MDS_OP_MKSNAP;
810 		dout("mksnap dir %p snap '%pd' dn %p\n", dir,
811 		     dentry, dentry);
812 	} else if (ceph_snap(dir) == CEPH_NOSNAP) {
813 		dout("mkdir dir %p dn %p mode 0%ho\n", dir, dentry, mode);
814 		op = CEPH_MDS_OP_MKDIR;
815 	} else {
816 		goto out;
817 	}
818 
819 	mode |= S_IFDIR;
820 	err = ceph_pre_init_acls(dir, &mode, &acls);
821 	if (err < 0)
822 		goto out;
823 
824 	req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
825 	if (IS_ERR(req)) {
826 		err = PTR_ERR(req);
827 		goto out;
828 	}
829 
830 	req->r_dentry = dget(dentry);
831 	req->r_num_caps = 2;
832 	req->r_locked_dir = dir;
833 	req->r_args.mkdir.mode = cpu_to_le32(mode);
834 	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
835 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
836 	if (acls.pagelist) {
837 		req->r_pagelist = acls.pagelist;
838 		acls.pagelist = NULL;
839 	}
840 	err = ceph_mdsc_do_request(mdsc, dir, req);
841 	if (!err &&
842 	    !req->r_reply_info.head->is_target &&
843 	    !req->r_reply_info.head->is_dentry)
844 		err = ceph_handle_notrace_create(dir, dentry);
845 	ceph_mdsc_put_request(req);
846 out:
847 	if (!err)
848 		ceph_init_inode_acls(d_inode(dentry), &acls);
849 	else
850 		d_drop(dentry);
851 	ceph_release_acls_info(&acls);
852 	return err;
853 }
854 
855 static int ceph_link(struct dentry *old_dentry, struct inode *dir,
856 		     struct dentry *dentry)
857 {
858 	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
859 	struct ceph_mds_client *mdsc = fsc->mdsc;
860 	struct ceph_mds_request *req;
861 	int err;
862 
863 	if (ceph_snap(dir) != CEPH_NOSNAP)
864 		return -EROFS;
865 
866 	dout("link in dir %p old_dentry %p dentry %p\n", dir,
867 	     old_dentry, dentry);
868 	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LINK, USE_AUTH_MDS);
869 	if (IS_ERR(req)) {
870 		d_drop(dentry);
871 		return PTR_ERR(req);
872 	}
873 	req->r_dentry = dget(dentry);
874 	req->r_num_caps = 2;
875 	req->r_old_dentry = dget(old_dentry);
876 	req->r_locked_dir = dir;
877 	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
878 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
879 	/* release LINK_SHARED on source inode (mds will lock it) */
880 	req->r_old_inode_drop = CEPH_CAP_LINK_SHARED;
881 	err = ceph_mdsc_do_request(mdsc, dir, req);
882 	if (err) {
883 		d_drop(dentry);
884 	} else if (!req->r_reply_info.head->is_dentry) {
885 		ihold(d_inode(old_dentry));
886 		d_instantiate(dentry, d_inode(old_dentry));
887 	}
888 	ceph_mdsc_put_request(req);
889 	return err;
890 }
891 
892 /*
893  * For a soon-to-be unlinked file, drop the AUTH_RDCACHE caps.  If it
894  * looks like the link count will hit 0, drop any other caps (other
895  * than PIN) we don't specifically want (due to the file still being
896  * open).
897  */
898 static int drop_caps_for_unlink(struct inode *inode)
899 {
900 	struct ceph_inode_info *ci = ceph_inode(inode);
901 	int drop = CEPH_CAP_LINK_SHARED | CEPH_CAP_LINK_EXCL;
902 
903 	spin_lock(&ci->i_ceph_lock);
904 	if (inode->i_nlink == 1) {
905 		drop |= ~(__ceph_caps_wanted(ci) | CEPH_CAP_PIN);
906 		ci->i_ceph_flags |= CEPH_I_NODELAY;
907 	}
908 	spin_unlock(&ci->i_ceph_lock);
909 	return drop;
910 }
911 
912 /*
913  * rmdir and unlink are differ only by the metadata op code
914  */
915 static int ceph_unlink(struct inode *dir, struct dentry *dentry)
916 {
917 	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
918 	struct ceph_mds_client *mdsc = fsc->mdsc;
919 	struct inode *inode = d_inode(dentry);
920 	struct ceph_mds_request *req;
921 	int err = -EROFS;
922 	int op;
923 
924 	if (ceph_snap(dir) == CEPH_SNAPDIR) {
925 		/* rmdir .snap/foo is RMSNAP */
926 		dout("rmsnap dir %p '%pd' dn %p\n", dir, dentry, dentry);
927 		op = CEPH_MDS_OP_RMSNAP;
928 	} else if (ceph_snap(dir) == CEPH_NOSNAP) {
929 		dout("unlink/rmdir dir %p dn %p inode %p\n",
930 		     dir, dentry, inode);
931 		op = d_is_dir(dentry) ?
932 			CEPH_MDS_OP_RMDIR : CEPH_MDS_OP_UNLINK;
933 	} else
934 		goto out;
935 	req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
936 	if (IS_ERR(req)) {
937 		err = PTR_ERR(req);
938 		goto out;
939 	}
940 	req->r_dentry = dget(dentry);
941 	req->r_num_caps = 2;
942 	req->r_locked_dir = dir;
943 	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
944 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
945 	req->r_inode_drop = drop_caps_for_unlink(inode);
946 	err = ceph_mdsc_do_request(mdsc, dir, req);
947 	if (!err && !req->r_reply_info.head->is_dentry)
948 		d_delete(dentry);
949 	ceph_mdsc_put_request(req);
950 out:
951 	return err;
952 }
953 
954 static int ceph_rename(struct inode *old_dir, struct dentry *old_dentry,
955 		       struct inode *new_dir, struct dentry *new_dentry)
956 {
957 	struct ceph_fs_client *fsc = ceph_sb_to_client(old_dir->i_sb);
958 	struct ceph_mds_client *mdsc = fsc->mdsc;
959 	struct ceph_mds_request *req;
960 	int op = CEPH_MDS_OP_RENAME;
961 	int err;
962 
963 	if (ceph_snap(old_dir) != ceph_snap(new_dir))
964 		return -EXDEV;
965 	if (ceph_snap(old_dir) != CEPH_NOSNAP) {
966 		if (old_dir == new_dir && ceph_snap(old_dir) == CEPH_SNAPDIR)
967 			op = CEPH_MDS_OP_RENAMESNAP;
968 		else
969 			return -EROFS;
970 	}
971 	dout("rename dir %p dentry %p to dir %p dentry %p\n",
972 	     old_dir, old_dentry, new_dir, new_dentry);
973 	req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
974 	if (IS_ERR(req))
975 		return PTR_ERR(req);
976 	ihold(old_dir);
977 	req->r_dentry = dget(new_dentry);
978 	req->r_num_caps = 2;
979 	req->r_old_dentry = dget(old_dentry);
980 	req->r_old_dentry_dir = old_dir;
981 	req->r_locked_dir = new_dir;
982 	req->r_old_dentry_drop = CEPH_CAP_FILE_SHARED;
983 	req->r_old_dentry_unless = CEPH_CAP_FILE_EXCL;
984 	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
985 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
986 	/* release LINK_RDCACHE on source inode (mds will lock it) */
987 	req->r_old_inode_drop = CEPH_CAP_LINK_SHARED;
988 	if (d_really_is_positive(new_dentry))
989 		req->r_inode_drop = drop_caps_for_unlink(d_inode(new_dentry));
990 	err = ceph_mdsc_do_request(mdsc, old_dir, req);
991 	if (!err && !req->r_reply_info.head->is_dentry) {
992 		/*
993 		 * Normally d_move() is done by fill_trace (called by
994 		 * do_request, above).  If there is no trace, we need
995 		 * to do it here.
996 		 */
997 
998 		/* d_move screws up sibling dentries' offsets */
999 		ceph_dir_clear_complete(old_dir);
1000 		ceph_dir_clear_complete(new_dir);
1001 
1002 		d_move(old_dentry, new_dentry);
1003 
1004 		/* ensure target dentry is invalidated, despite
1005 		   rehashing bug in vfs_rename_dir */
1006 		ceph_invalidate_dentry_lease(new_dentry);
1007 	}
1008 	ceph_mdsc_put_request(req);
1009 	return err;
1010 }
1011 
1012 /*
1013  * Ensure a dentry lease will no longer revalidate.
1014  */
1015 void ceph_invalidate_dentry_lease(struct dentry *dentry)
1016 {
1017 	spin_lock(&dentry->d_lock);
1018 	dentry->d_time = jiffies;
1019 	ceph_dentry(dentry)->lease_shared_gen = 0;
1020 	spin_unlock(&dentry->d_lock);
1021 }
1022 
1023 /*
1024  * Check if dentry lease is valid.  If not, delete the lease.  Try to
1025  * renew if the least is more than half up.
1026  */
1027 static int dentry_lease_is_valid(struct dentry *dentry)
1028 {
1029 	struct ceph_dentry_info *di;
1030 	struct ceph_mds_session *s;
1031 	int valid = 0;
1032 	u32 gen;
1033 	unsigned long ttl;
1034 	struct ceph_mds_session *session = NULL;
1035 	struct inode *dir = NULL;
1036 	u32 seq = 0;
1037 
1038 	spin_lock(&dentry->d_lock);
1039 	di = ceph_dentry(dentry);
1040 	if (di->lease_session) {
1041 		s = di->lease_session;
1042 		spin_lock(&s->s_gen_ttl_lock);
1043 		gen = s->s_cap_gen;
1044 		ttl = s->s_cap_ttl;
1045 		spin_unlock(&s->s_gen_ttl_lock);
1046 
1047 		if (di->lease_gen == gen &&
1048 		    time_before(jiffies, dentry->d_time) &&
1049 		    time_before(jiffies, ttl)) {
1050 			valid = 1;
1051 			if (di->lease_renew_after &&
1052 			    time_after(jiffies, di->lease_renew_after)) {
1053 				/* we should renew */
1054 				dir = d_inode(dentry->d_parent);
1055 				session = ceph_get_mds_session(s);
1056 				seq = di->lease_seq;
1057 				di->lease_renew_after = 0;
1058 				di->lease_renew_from = jiffies;
1059 			}
1060 		}
1061 	}
1062 	spin_unlock(&dentry->d_lock);
1063 
1064 	if (session) {
1065 		ceph_mdsc_lease_send_msg(session, dir, dentry,
1066 					 CEPH_MDS_LEASE_RENEW, seq);
1067 		ceph_put_mds_session(session);
1068 	}
1069 	dout("dentry_lease_is_valid - dentry %p = %d\n", dentry, valid);
1070 	return valid;
1071 }
1072 
1073 /*
1074  * Check if directory-wide content lease/cap is valid.
1075  */
1076 static int dir_lease_is_valid(struct inode *dir, struct dentry *dentry)
1077 {
1078 	struct ceph_inode_info *ci = ceph_inode(dir);
1079 	struct ceph_dentry_info *di = ceph_dentry(dentry);
1080 	int valid = 0;
1081 
1082 	spin_lock(&ci->i_ceph_lock);
1083 	if (ci->i_shared_gen == di->lease_shared_gen)
1084 		valid = __ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1);
1085 	spin_unlock(&ci->i_ceph_lock);
1086 	dout("dir_lease_is_valid dir %p v%u dentry %p v%u = %d\n",
1087 	     dir, (unsigned)ci->i_shared_gen, dentry,
1088 	     (unsigned)di->lease_shared_gen, valid);
1089 	return valid;
1090 }
1091 
1092 /*
1093  * Check if cached dentry can be trusted.
1094  */
1095 static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
1096 {
1097 	int valid = 0;
1098 	struct inode *dir;
1099 
1100 	if (flags & LOOKUP_RCU)
1101 		return -ECHILD;
1102 
1103 	dout("d_revalidate %p '%pd' inode %p offset %lld\n", dentry,
1104 	     dentry, d_inode(dentry), ceph_dentry(dentry)->offset);
1105 
1106 	dir = ceph_get_dentry_parent_inode(dentry);
1107 
1108 	/* always trust cached snapped dentries, snapdir dentry */
1109 	if (ceph_snap(dir) != CEPH_NOSNAP) {
1110 		dout("d_revalidate %p '%pd' inode %p is SNAPPED\n", dentry,
1111 		     dentry, d_inode(dentry));
1112 		valid = 1;
1113 	} else if (d_really_is_positive(dentry) &&
1114 		   ceph_snap(d_inode(dentry)) == CEPH_SNAPDIR) {
1115 		valid = 1;
1116 	} else if (dentry_lease_is_valid(dentry) ||
1117 		   dir_lease_is_valid(dir, dentry)) {
1118 		if (d_really_is_positive(dentry))
1119 			valid = ceph_is_any_caps(d_inode(dentry));
1120 		else
1121 			valid = 1;
1122 	}
1123 
1124 	dout("d_revalidate %p %s\n", dentry, valid ? "valid" : "invalid");
1125 	if (valid) {
1126 		ceph_dentry_lru_touch(dentry);
1127 	} else {
1128 		ceph_dir_clear_complete(dir);
1129 	}
1130 	iput(dir);
1131 	return valid;
1132 }
1133 
1134 /*
1135  * Release our ceph_dentry_info.
1136  */
1137 static void ceph_d_release(struct dentry *dentry)
1138 {
1139 	struct ceph_dentry_info *di = ceph_dentry(dentry);
1140 
1141 	dout("d_release %p\n", dentry);
1142 	ceph_dentry_lru_del(dentry);
1143 	if (di->lease_session)
1144 		ceph_put_mds_session(di->lease_session);
1145 	kmem_cache_free(ceph_dentry_cachep, di);
1146 	dentry->d_fsdata = NULL;
1147 }
1148 
1149 static int ceph_snapdir_d_revalidate(struct dentry *dentry,
1150 					  unsigned int flags)
1151 {
1152 	/*
1153 	 * Eventually, we'll want to revalidate snapped metadata
1154 	 * too... probably...
1155 	 */
1156 	return 1;
1157 }
1158 
1159 /*
1160  * When the VFS prunes a dentry from the cache, we need to clear the
1161  * complete flag on the parent directory.
1162  *
1163  * Called under dentry->d_lock.
1164  */
1165 static void ceph_d_prune(struct dentry *dentry)
1166 {
1167 	dout("ceph_d_prune %p\n", dentry);
1168 
1169 	/* do we have a valid parent? */
1170 	if (IS_ROOT(dentry))
1171 		return;
1172 
1173 	/* if we are not hashed, we don't affect dir's completeness */
1174 	if (d_unhashed(dentry))
1175 		return;
1176 
1177 	/*
1178 	 * we hold d_lock, so d_parent is stable, and d_fsdata is never
1179 	 * cleared until d_release
1180 	 */
1181 	ceph_dir_clear_complete(d_inode(dentry->d_parent));
1182 }
1183 
1184 /*
1185  * read() on a dir.  This weird interface hack only works if mounted
1186  * with '-o dirstat'.
1187  */
1188 static ssize_t ceph_read_dir(struct file *file, char __user *buf, size_t size,
1189 			     loff_t *ppos)
1190 {
1191 	struct ceph_file_info *cf = file->private_data;
1192 	struct inode *inode = file_inode(file);
1193 	struct ceph_inode_info *ci = ceph_inode(inode);
1194 	int left;
1195 	const int bufsize = 1024;
1196 
1197 	if (!ceph_test_mount_opt(ceph_sb_to_client(inode->i_sb), DIRSTAT))
1198 		return -EISDIR;
1199 
1200 	if (!cf->dir_info) {
1201 		cf->dir_info = kmalloc(bufsize, GFP_KERNEL);
1202 		if (!cf->dir_info)
1203 			return -ENOMEM;
1204 		cf->dir_info_len =
1205 			snprintf(cf->dir_info, bufsize,
1206 				"entries:   %20lld\n"
1207 				" files:    %20lld\n"
1208 				" subdirs:  %20lld\n"
1209 				"rentries:  %20lld\n"
1210 				" rfiles:   %20lld\n"
1211 				" rsubdirs: %20lld\n"
1212 				"rbytes:    %20lld\n"
1213 				"rctime:    %10ld.%09ld\n",
1214 				ci->i_files + ci->i_subdirs,
1215 				ci->i_files,
1216 				ci->i_subdirs,
1217 				ci->i_rfiles + ci->i_rsubdirs,
1218 				ci->i_rfiles,
1219 				ci->i_rsubdirs,
1220 				ci->i_rbytes,
1221 				(long)ci->i_rctime.tv_sec,
1222 				(long)ci->i_rctime.tv_nsec);
1223 	}
1224 
1225 	if (*ppos >= cf->dir_info_len)
1226 		return 0;
1227 	size = min_t(unsigned, size, cf->dir_info_len-*ppos);
1228 	left = copy_to_user(buf, cf->dir_info + *ppos, size);
1229 	if (left == size)
1230 		return -EFAULT;
1231 	*ppos += (size - left);
1232 	return size - left;
1233 }
1234 
1235 /*
1236  * We maintain a private dentry LRU.
1237  *
1238  * FIXME: this needs to be changed to a per-mds lru to be useful.
1239  */
1240 void ceph_dentry_lru_add(struct dentry *dn)
1241 {
1242 	struct ceph_dentry_info *di = ceph_dentry(dn);
1243 	struct ceph_mds_client *mdsc;
1244 
1245 	dout("dentry_lru_add %p %p '%pd'\n", di, dn, dn);
1246 	mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
1247 	spin_lock(&mdsc->dentry_lru_lock);
1248 	list_add_tail(&di->lru, &mdsc->dentry_lru);
1249 	mdsc->num_dentry++;
1250 	spin_unlock(&mdsc->dentry_lru_lock);
1251 }
1252 
1253 void ceph_dentry_lru_touch(struct dentry *dn)
1254 {
1255 	struct ceph_dentry_info *di = ceph_dentry(dn);
1256 	struct ceph_mds_client *mdsc;
1257 
1258 	dout("dentry_lru_touch %p %p '%pd' (offset %lld)\n", di, dn, dn,
1259 	     di->offset);
1260 	mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
1261 	spin_lock(&mdsc->dentry_lru_lock);
1262 	list_move_tail(&di->lru, &mdsc->dentry_lru);
1263 	spin_unlock(&mdsc->dentry_lru_lock);
1264 }
1265 
1266 void ceph_dentry_lru_del(struct dentry *dn)
1267 {
1268 	struct ceph_dentry_info *di = ceph_dentry(dn);
1269 	struct ceph_mds_client *mdsc;
1270 
1271 	dout("dentry_lru_del %p %p '%pd'\n", di, dn, dn);
1272 	mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
1273 	spin_lock(&mdsc->dentry_lru_lock);
1274 	list_del_init(&di->lru);
1275 	mdsc->num_dentry--;
1276 	spin_unlock(&mdsc->dentry_lru_lock);
1277 }
1278 
1279 /*
1280  * Return name hash for a given dentry.  This is dependent on
1281  * the parent directory's hash function.
1282  */
1283 unsigned ceph_dentry_hash(struct inode *dir, struct dentry *dn)
1284 {
1285 	struct ceph_inode_info *dci = ceph_inode(dir);
1286 
1287 	switch (dci->i_dir_layout.dl_dir_hash) {
1288 	case 0:	/* for backward compat */
1289 	case CEPH_STR_HASH_LINUX:
1290 		return dn->d_name.hash;
1291 
1292 	default:
1293 		return ceph_str_hash(dci->i_dir_layout.dl_dir_hash,
1294 				     dn->d_name.name, dn->d_name.len);
1295 	}
1296 }
1297 
1298 const struct file_operations ceph_dir_fops = {
1299 	.read = ceph_read_dir,
1300 	.iterate = ceph_readdir,
1301 	.llseek = ceph_dir_llseek,
1302 	.open = ceph_open,
1303 	.release = ceph_release,
1304 	.unlocked_ioctl = ceph_ioctl,
1305 	.fsync = ceph_fsync,
1306 };
1307 
1308 const struct file_operations ceph_snapdir_fops = {
1309 	.iterate = ceph_readdir,
1310 	.llseek = ceph_dir_llseek,
1311 	.open = ceph_open,
1312 	.release = ceph_release,
1313 };
1314 
1315 const struct inode_operations ceph_dir_iops = {
1316 	.lookup = ceph_lookup,
1317 	.permission = ceph_permission,
1318 	.getattr = ceph_getattr,
1319 	.setattr = ceph_setattr,
1320 	.setxattr = ceph_setxattr,
1321 	.getxattr = ceph_getxattr,
1322 	.listxattr = ceph_listxattr,
1323 	.removexattr = ceph_removexattr,
1324 	.get_acl = ceph_get_acl,
1325 	.set_acl = ceph_set_acl,
1326 	.mknod = ceph_mknod,
1327 	.symlink = ceph_symlink,
1328 	.mkdir = ceph_mkdir,
1329 	.link = ceph_link,
1330 	.unlink = ceph_unlink,
1331 	.rmdir = ceph_unlink,
1332 	.rename = ceph_rename,
1333 	.create = ceph_create,
1334 	.atomic_open = ceph_atomic_open,
1335 };
1336 
1337 const struct inode_operations ceph_snapdir_iops = {
1338 	.lookup = ceph_lookup,
1339 	.permission = ceph_permission,
1340 	.getattr = ceph_getattr,
1341 	.mkdir = ceph_mkdir,
1342 	.rmdir = ceph_unlink,
1343 	.rename = ceph_rename,
1344 };
1345 
1346 const struct dentry_operations ceph_dentry_ops = {
1347 	.d_revalidate = ceph_d_revalidate,
1348 	.d_release = ceph_d_release,
1349 	.d_prune = ceph_d_prune,
1350 };
1351 
1352 const struct dentry_operations ceph_snapdir_dentry_ops = {
1353 	.d_revalidate = ceph_snapdir_d_revalidate,
1354 	.d_release = ceph_d_release,
1355 };
1356 
1357 const struct dentry_operations ceph_snap_dentry_ops = {
1358 	.d_release = ceph_d_release,
1359 	.d_prune = ceph_d_prune,
1360 };
1361