xref: /linux/fs/ceph/dir.c (revision 2c1ba398ac9da3305815f6ae8e95ae2b9fd3b5ff)
1 #include <linux/ceph/ceph_debug.h>
2 
3 #include <linux/spinlock.h>
4 #include <linux/fs_struct.h>
5 #include <linux/namei.h>
6 #include <linux/slab.h>
7 #include <linux/sched.h>
8 
9 #include "super.h"
10 #include "mds_client.h"
11 
12 /*
13  * Directory operations: readdir, lookup, create, link, unlink,
14  * rename, etc.
15  */
16 
17 /*
18  * Ceph MDS operations are specified in terms of a base ino and
19  * relative path.  Thus, the client can specify an operation on a
20  * specific inode (e.g., a getattr due to fstat(2)), or as a path
21  * relative to, say, the root directory.
22  *
23  * Normally, we limit ourselves to strict inode ops (no path component)
24  * or dentry operations (a single path component relative to an ino).  The
25  * exception to this is open_root_dentry(), which will open the mount
26  * point by name.
27  */
28 
29 const struct inode_operations ceph_dir_iops;
30 const struct file_operations ceph_dir_fops;
31 const struct dentry_operations ceph_dentry_ops;
32 
33 /*
34  * Initialize ceph dentry state.
35  */
36 int ceph_init_dentry(struct dentry *dentry)
37 {
38 	struct ceph_dentry_info *di;
39 
40 	if (dentry->d_fsdata)
41 		return 0;
42 
43 	di = kmem_cache_alloc(ceph_dentry_cachep, GFP_NOFS | __GFP_ZERO);
44 	if (!di)
45 		return -ENOMEM;          /* oh well */
46 
47 	spin_lock(&dentry->d_lock);
48 	if (dentry->d_fsdata) {
49 		/* lost a race */
50 		kmem_cache_free(ceph_dentry_cachep, di);
51 		goto out_unlock;
52 	}
53 
54 	if (dentry->d_parent == NULL ||   /* nfs fh_to_dentry */
55 	    ceph_snap(dentry->d_parent->d_inode) == CEPH_NOSNAP)
56 		d_set_d_op(dentry, &ceph_dentry_ops);
57 	else if (ceph_snap(dentry->d_parent->d_inode) == CEPH_SNAPDIR)
58 		d_set_d_op(dentry, &ceph_snapdir_dentry_ops);
59 	else
60 		d_set_d_op(dentry, &ceph_snap_dentry_ops);
61 
62 	di->dentry = dentry;
63 	di->lease_session = NULL;
64 	dentry->d_time = jiffies;
65 	/* avoid reordering d_fsdata setup so that the check above is safe */
66 	smp_mb();
67 	dentry->d_fsdata = di;
68 	ceph_dentry_lru_add(dentry);
69 out_unlock:
70 	spin_unlock(&dentry->d_lock);
71 	return 0;
72 }
73 
74 struct inode *ceph_get_dentry_parent_inode(struct dentry *dentry)
75 {
76 	struct inode *inode = NULL;
77 
78 	if (!dentry)
79 		return NULL;
80 
81 	spin_lock(&dentry->d_lock);
82 	if (dentry->d_parent) {
83 		inode = dentry->d_parent->d_inode;
84 		ihold(inode);
85 	}
86 	spin_unlock(&dentry->d_lock);
87 	return inode;
88 }
89 
90 
91 /*
92  * for readdir, we encode the directory frag and offset within that
93  * frag into f_pos.
94  */
95 static unsigned fpos_frag(loff_t p)
96 {
97 	return p >> 32;
98 }
99 static unsigned fpos_off(loff_t p)
100 {
101 	return p & 0xffffffff;
102 }
103 
104 /*
105  * When possible, we try to satisfy a readdir by peeking at the
106  * dcache.  We make this work by carefully ordering dentries on
107  * d_u.d_child when we initially get results back from the MDS, and
108  * falling back to a "normal" sync readdir if any dentries in the dir
109  * are dropped.
110  *
111  * I_COMPLETE tells indicates we have all dentries in the dir.  It is
112  * defined IFF we hold CEPH_CAP_FILE_SHARED (which will be revoked by
113  * the MDS if/when the directory is modified).
114  */
115 static int __dcache_readdir(struct file *filp,
116 			    void *dirent, filldir_t filldir)
117 {
118 	struct ceph_file_info *fi = filp->private_data;
119 	struct dentry *parent = filp->f_dentry;
120 	struct inode *dir = parent->d_inode;
121 	struct list_head *p;
122 	struct dentry *dentry, *last;
123 	struct ceph_dentry_info *di;
124 	int err = 0;
125 
126 	/* claim ref on last dentry we returned */
127 	last = fi->dentry;
128 	fi->dentry = NULL;
129 
130 	dout("__dcache_readdir %p at %llu (last %p)\n", dir, filp->f_pos,
131 	     last);
132 
133 	spin_lock(&parent->d_lock);
134 
135 	/* start at beginning? */
136 	if (filp->f_pos == 2 || last == NULL ||
137 	    filp->f_pos < ceph_dentry(last)->offset) {
138 		if (list_empty(&parent->d_subdirs))
139 			goto out_unlock;
140 		p = parent->d_subdirs.prev;
141 		dout(" initial p %p/%p\n", p->prev, p->next);
142 	} else {
143 		p = last->d_u.d_child.prev;
144 	}
145 
146 more:
147 	dentry = list_entry(p, struct dentry, d_u.d_child);
148 	di = ceph_dentry(dentry);
149 	while (1) {
150 		dout(" p %p/%p %s d_subdirs %p/%p\n", p->prev, p->next,
151 		     d_unhashed(dentry) ? "!hashed" : "hashed",
152 		     parent->d_subdirs.prev, parent->d_subdirs.next);
153 		if (p == &parent->d_subdirs) {
154 			fi->flags |= CEPH_F_ATEND;
155 			goto out_unlock;
156 		}
157 		spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
158 		if (!d_unhashed(dentry) && dentry->d_inode &&
159 		    ceph_snap(dentry->d_inode) != CEPH_SNAPDIR &&
160 		    ceph_ino(dentry->d_inode) != CEPH_INO_CEPH &&
161 		    filp->f_pos <= di->offset)
162 			break;
163 		dout(" skipping %p %.*s at %llu (%llu)%s%s\n", dentry,
164 		     dentry->d_name.len, dentry->d_name.name, di->offset,
165 		     filp->f_pos, d_unhashed(dentry) ? " unhashed" : "",
166 		     !dentry->d_inode ? " null" : "");
167 		spin_unlock(&dentry->d_lock);
168 		p = p->prev;
169 		dentry = list_entry(p, struct dentry, d_u.d_child);
170 		di = ceph_dentry(dentry);
171 	}
172 
173 	dget_dlock(dentry);
174 	spin_unlock(&dentry->d_lock);
175 	spin_unlock(&parent->d_lock);
176 
177 	dout(" %llu (%llu) dentry %p %.*s %p\n", di->offset, filp->f_pos,
178 	     dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode);
179 	filp->f_pos = di->offset;
180 	err = filldir(dirent, dentry->d_name.name,
181 		      dentry->d_name.len, di->offset,
182 		      ceph_translate_ino(dentry->d_sb, dentry->d_inode->i_ino),
183 		      dentry->d_inode->i_mode >> 12);
184 
185 	if (last) {
186 		if (err < 0) {
187 			/* remember our position */
188 			fi->dentry = last;
189 			fi->next_offset = di->offset;
190 		} else {
191 			dput(last);
192 		}
193 	}
194 	last = dentry;
195 
196 	if (err < 0)
197 		goto out;
198 
199 	filp->f_pos++;
200 
201 	/* make sure a dentry wasn't dropped while we didn't have parent lock */
202 	if (!ceph_i_test(dir, CEPH_I_COMPLETE)) {
203 		dout(" lost I_COMPLETE on %p; falling back to mds\n", dir);
204 		err = -EAGAIN;
205 		goto out;
206 	}
207 
208 	spin_lock(&parent->d_lock);
209 	p = p->prev;	/* advance to next dentry */
210 	goto more;
211 
212 out_unlock:
213 	spin_unlock(&parent->d_lock);
214 out:
215 	if (last)
216 		dput(last);
217 	return err;
218 }
219 
220 /*
221  * make note of the last dentry we read, so we can
222  * continue at the same lexicographical point,
223  * regardless of what dir changes take place on the
224  * server.
225  */
226 static int note_last_dentry(struct ceph_file_info *fi, const char *name,
227 			    int len)
228 {
229 	kfree(fi->last_name);
230 	fi->last_name = kmalloc(len+1, GFP_NOFS);
231 	if (!fi->last_name)
232 		return -ENOMEM;
233 	memcpy(fi->last_name, name, len);
234 	fi->last_name[len] = 0;
235 	dout("note_last_dentry '%s'\n", fi->last_name);
236 	return 0;
237 }
238 
239 static int ceph_readdir(struct file *filp, void *dirent, filldir_t filldir)
240 {
241 	struct ceph_file_info *fi = filp->private_data;
242 	struct inode *inode = filp->f_dentry->d_inode;
243 	struct ceph_inode_info *ci = ceph_inode(inode);
244 	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
245 	struct ceph_mds_client *mdsc = fsc->mdsc;
246 	unsigned frag = fpos_frag(filp->f_pos);
247 	int off = fpos_off(filp->f_pos);
248 	int err;
249 	u32 ftype;
250 	struct ceph_mds_reply_info_parsed *rinfo;
251 	const int max_entries = fsc->mount_options->max_readdir;
252 	const int max_bytes = fsc->mount_options->max_readdir_bytes;
253 
254 	dout("readdir %p filp %p frag %u off %u\n", inode, filp, frag, off);
255 	if (fi->flags & CEPH_F_ATEND)
256 		return 0;
257 
258 	/* always start with . and .. */
259 	if (filp->f_pos == 0) {
260 		/* note dir version at start of readdir so we can tell
261 		 * if any dentries get dropped */
262 		fi->dir_release_count = ci->i_release_count;
263 
264 		dout("readdir off 0 -> '.'\n");
265 		if (filldir(dirent, ".", 1, ceph_make_fpos(0, 0),
266 			    ceph_translate_ino(inode->i_sb, inode->i_ino),
267 			    inode->i_mode >> 12) < 0)
268 			return 0;
269 		filp->f_pos = 1;
270 		off = 1;
271 	}
272 	if (filp->f_pos == 1) {
273 		ino_t ino = parent_ino(filp->f_dentry);
274 		dout("readdir off 1 -> '..'\n");
275 		if (filldir(dirent, "..", 2, ceph_make_fpos(0, 1),
276 			    ceph_translate_ino(inode->i_sb, ino),
277 			    inode->i_mode >> 12) < 0)
278 			return 0;
279 		filp->f_pos = 2;
280 		off = 2;
281 	}
282 
283 	/* can we use the dcache? */
284 	spin_lock(&inode->i_lock);
285 	if ((filp->f_pos == 2 || fi->dentry) &&
286 	    !ceph_test_mount_opt(fsc, NOASYNCREADDIR) &&
287 	    ceph_snap(inode) != CEPH_SNAPDIR &&
288 	    (ci->i_ceph_flags & CEPH_I_COMPLETE) &&
289 	    __ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1)) {
290 		spin_unlock(&inode->i_lock);
291 		err = __dcache_readdir(filp, dirent, filldir);
292 		if (err != -EAGAIN)
293 			return err;
294 	} else {
295 		spin_unlock(&inode->i_lock);
296 	}
297 	if (fi->dentry) {
298 		err = note_last_dentry(fi, fi->dentry->d_name.name,
299 				       fi->dentry->d_name.len);
300 		if (err)
301 			return err;
302 		dput(fi->dentry);
303 		fi->dentry = NULL;
304 	}
305 
306 	/* proceed with a normal readdir */
307 
308 more:
309 	/* do we have the correct frag content buffered? */
310 	if (fi->frag != frag || fi->last_readdir == NULL) {
311 		struct ceph_mds_request *req;
312 		int op = ceph_snap(inode) == CEPH_SNAPDIR ?
313 			CEPH_MDS_OP_LSSNAP : CEPH_MDS_OP_READDIR;
314 
315 		/* discard old result, if any */
316 		if (fi->last_readdir) {
317 			ceph_mdsc_put_request(fi->last_readdir);
318 			fi->last_readdir = NULL;
319 		}
320 
321 		/* requery frag tree, as the frag topology may have changed */
322 		frag = ceph_choose_frag(ceph_inode(inode), frag, NULL, NULL);
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 		req->r_inode = inode;
330 		ihold(inode);
331 		req->r_dentry = dget(filp->f_dentry);
332 		/* hints to request -> mds selection code */
333 		req->r_direct_mode = USE_AUTH_MDS;
334 		req->r_direct_hash = ceph_frag_value(frag);
335 		req->r_direct_is_hash = true;
336 		req->r_path2 = kstrdup(fi->last_name, GFP_NOFS);
337 		req->r_readdir_offset = fi->next_offset;
338 		req->r_args.readdir.frag = cpu_to_le32(frag);
339 		req->r_args.readdir.max_entries = cpu_to_le32(max_entries);
340 		req->r_args.readdir.max_bytes = cpu_to_le32(max_bytes);
341 		req->r_num_caps = max_entries + 1;
342 		err = ceph_mdsc_do_request(mdsc, NULL, req);
343 		if (err < 0) {
344 			ceph_mdsc_put_request(req);
345 			return err;
346 		}
347 		dout("readdir got and parsed readdir result=%d"
348 		     " on frag %x, end=%d, complete=%d\n", err, frag,
349 		     (int)req->r_reply_info.dir_end,
350 		     (int)req->r_reply_info.dir_complete);
351 
352 		if (!req->r_did_prepopulate) {
353 			dout("readdir !did_prepopulate");
354 			fi->dir_release_count--;    /* preclude I_COMPLETE */
355 		}
356 
357 		/* note next offset and last dentry name */
358 		fi->offset = fi->next_offset;
359 		fi->last_readdir = req;
360 
361 		if (req->r_reply_info.dir_end) {
362 			kfree(fi->last_name);
363 			fi->last_name = NULL;
364 			if (ceph_frag_is_rightmost(frag))
365 				fi->next_offset = 2;
366 			else
367 				fi->next_offset = 0;
368 		} else {
369 			rinfo = &req->r_reply_info;
370 			err = note_last_dentry(fi,
371 				       rinfo->dir_dname[rinfo->dir_nr-1],
372 				       rinfo->dir_dname_len[rinfo->dir_nr-1]);
373 			if (err)
374 				return err;
375 			fi->next_offset += rinfo->dir_nr;
376 		}
377 	}
378 
379 	rinfo = &fi->last_readdir->r_reply_info;
380 	dout("readdir frag %x num %d off %d chunkoff %d\n", frag,
381 	     rinfo->dir_nr, off, fi->offset);
382 	while (off >= fi->offset && off - fi->offset < rinfo->dir_nr) {
383 		u64 pos = ceph_make_fpos(frag, off);
384 		struct ceph_mds_reply_inode *in =
385 			rinfo->dir_in[off - fi->offset].in;
386 		struct ceph_vino vino;
387 		ino_t ino;
388 
389 		dout("readdir off %d (%d/%d) -> %lld '%.*s' %p\n",
390 		     off, off - fi->offset, rinfo->dir_nr, pos,
391 		     rinfo->dir_dname_len[off - fi->offset],
392 		     rinfo->dir_dname[off - fi->offset], in);
393 		BUG_ON(!in);
394 		ftype = le32_to_cpu(in->mode) >> 12;
395 		vino.ino = le64_to_cpu(in->ino);
396 		vino.snap = le64_to_cpu(in->snapid);
397 		ino = ceph_vino_to_ino(vino);
398 		if (filldir(dirent,
399 			    rinfo->dir_dname[off - fi->offset],
400 			    rinfo->dir_dname_len[off - fi->offset],
401 			    pos,
402 			    ceph_translate_ino(inode->i_sb, ino), ftype) < 0) {
403 			dout("filldir stopping us...\n");
404 			return 0;
405 		}
406 		off++;
407 		filp->f_pos = pos + 1;
408 	}
409 
410 	if (fi->last_name) {
411 		ceph_mdsc_put_request(fi->last_readdir);
412 		fi->last_readdir = NULL;
413 		goto more;
414 	}
415 
416 	/* more frags? */
417 	if (!ceph_frag_is_rightmost(frag)) {
418 		frag = ceph_frag_next(frag);
419 		off = 0;
420 		filp->f_pos = ceph_make_fpos(frag, off);
421 		dout("readdir next frag is %x\n", frag);
422 		goto more;
423 	}
424 	fi->flags |= CEPH_F_ATEND;
425 
426 	/*
427 	 * if dir_release_count still matches the dir, no dentries
428 	 * were released during the whole readdir, and we should have
429 	 * the complete dir contents in our cache.
430 	 */
431 	spin_lock(&inode->i_lock);
432 	if (ci->i_release_count == fi->dir_release_count) {
433 		dout(" marking %p complete\n", inode);
434 		/* ci->i_ceph_flags |= CEPH_I_COMPLETE; */
435 		ci->i_max_offset = filp->f_pos;
436 	}
437 	spin_unlock(&inode->i_lock);
438 
439 	dout("readdir %p filp %p done.\n", inode, filp);
440 	return 0;
441 }
442 
443 static void reset_readdir(struct ceph_file_info *fi)
444 {
445 	if (fi->last_readdir) {
446 		ceph_mdsc_put_request(fi->last_readdir);
447 		fi->last_readdir = NULL;
448 	}
449 	kfree(fi->last_name);
450 	fi->last_name = NULL;
451 	fi->next_offset = 2;  /* compensate for . and .. */
452 	if (fi->dentry) {
453 		dput(fi->dentry);
454 		fi->dentry = NULL;
455 	}
456 	fi->flags &= ~CEPH_F_ATEND;
457 }
458 
459 static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int origin)
460 {
461 	struct ceph_file_info *fi = file->private_data;
462 	struct inode *inode = file->f_mapping->host;
463 	loff_t old_offset = offset;
464 	loff_t retval;
465 
466 	mutex_lock(&inode->i_mutex);
467 	retval = -EINVAL;
468 	switch (origin) {
469 	case SEEK_END:
470 		offset += inode->i_size + 2;   /* FIXME */
471 		break;
472 	case SEEK_CUR:
473 		offset += file->f_pos;
474 	case SEEK_SET:
475 		break;
476 	default:
477 		goto out;
478 	}
479 
480 	if (offset >= 0 && offset <= inode->i_sb->s_maxbytes) {
481 		if (offset != file->f_pos) {
482 			file->f_pos = offset;
483 			file->f_version = 0;
484 			fi->flags &= ~CEPH_F_ATEND;
485 		}
486 		retval = offset;
487 
488 		/*
489 		 * discard buffered readdir content on seekdir(0), or
490 		 * seek to new frag, or seek prior to current chunk.
491 		 */
492 		if (offset == 0 ||
493 		    fpos_frag(offset) != fpos_frag(old_offset) ||
494 		    fpos_off(offset) < fi->offset) {
495 			dout("dir_llseek dropping %p content\n", file);
496 			reset_readdir(fi);
497 		}
498 
499 		/* bump dir_release_count if we did a forward seek */
500 		if (offset > old_offset)
501 			fi->dir_release_count--;
502 	}
503 out:
504 	mutex_unlock(&inode->i_mutex);
505 	return retval;
506 }
507 
508 /*
509  * Handle lookups for the hidden .snap directory.
510  */
511 int ceph_handle_snapdir(struct ceph_mds_request *req,
512 			struct dentry *dentry, int err)
513 {
514 	struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
515 	struct inode *parent = dentry->d_parent->d_inode; /* we hold i_mutex */
516 
517 	/* .snap dir? */
518 	if (err == -ENOENT &&
519 	    ceph_snap(parent) == CEPH_NOSNAP &&
520 	    strcmp(dentry->d_name.name,
521 		   fsc->mount_options->snapdir_name) == 0) {
522 		struct inode *inode = ceph_get_snapdir(parent);
523 		dout("ENOENT on snapdir %p '%.*s', linking to snapdir %p\n",
524 		     dentry, dentry->d_name.len, dentry->d_name.name, inode);
525 		BUG_ON(!d_unhashed(dentry));
526 		d_add(dentry, inode);
527 		err = 0;
528 	}
529 	return err;
530 }
531 
532 /*
533  * Figure out final result of a lookup/open request.
534  *
535  * Mainly, make sure we return the final req->r_dentry (if it already
536  * existed) in place of the original VFS-provided dentry when they
537  * differ.
538  *
539  * Gracefully handle the case where the MDS replies with -ENOENT and
540  * no trace (which it may do, at its discretion, e.g., if it doesn't
541  * care to issue a lease on the negative dentry).
542  */
543 struct dentry *ceph_finish_lookup(struct ceph_mds_request *req,
544 				  struct dentry *dentry, int err)
545 {
546 	if (err == -ENOENT) {
547 		/* no trace? */
548 		err = 0;
549 		if (!req->r_reply_info.head->is_dentry) {
550 			dout("ENOENT and no trace, dentry %p inode %p\n",
551 			     dentry, dentry->d_inode);
552 			if (dentry->d_inode) {
553 				d_drop(dentry);
554 				err = -ENOENT;
555 			} else {
556 				d_add(dentry, NULL);
557 			}
558 		}
559 	}
560 	if (err)
561 		dentry = ERR_PTR(err);
562 	else if (dentry != req->r_dentry)
563 		dentry = dget(req->r_dentry);   /* we got spliced */
564 	else
565 		dentry = NULL;
566 	return dentry;
567 }
568 
569 static int is_root_ceph_dentry(struct inode *inode, struct dentry *dentry)
570 {
571 	return ceph_ino(inode) == CEPH_INO_ROOT &&
572 		strncmp(dentry->d_name.name, ".ceph", 5) == 0;
573 }
574 
575 /*
576  * Look up a single dir entry.  If there is a lookup intent, inform
577  * the MDS so that it gets our 'caps wanted' value in a single op.
578  */
579 static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
580 				  struct nameidata *nd)
581 {
582 	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
583 	struct ceph_mds_client *mdsc = fsc->mdsc;
584 	struct ceph_mds_request *req;
585 	int op;
586 	int err;
587 
588 	dout("lookup %p dentry %p '%.*s'\n",
589 	     dir, dentry, dentry->d_name.len, dentry->d_name.name);
590 
591 	if (dentry->d_name.len > NAME_MAX)
592 		return ERR_PTR(-ENAMETOOLONG);
593 
594 	err = ceph_init_dentry(dentry);
595 	if (err < 0)
596 		return ERR_PTR(err);
597 
598 	/* open (but not create!) intent? */
599 	if (nd &&
600 	    (nd->flags & LOOKUP_OPEN) &&
601 	    !(nd->intent.open.flags & O_CREAT)) {
602 		int mode = nd->intent.open.create_mode & ~current->fs->umask;
603 		return ceph_lookup_open(dir, dentry, nd, mode, 1);
604 	}
605 
606 	/* can we conclude ENOENT locally? */
607 	if (dentry->d_inode == NULL) {
608 		struct ceph_inode_info *ci = ceph_inode(dir);
609 		struct ceph_dentry_info *di = ceph_dentry(dentry);
610 
611 		spin_lock(&dir->i_lock);
612 		dout(" dir %p flags are %d\n", dir, ci->i_ceph_flags);
613 		if (strncmp(dentry->d_name.name,
614 			    fsc->mount_options->snapdir_name,
615 			    dentry->d_name.len) &&
616 		    !is_root_ceph_dentry(dir, dentry) &&
617 		    (ci->i_ceph_flags & CEPH_I_COMPLETE) &&
618 		    (__ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1))) {
619 			spin_unlock(&dir->i_lock);
620 			dout(" dir %p complete, -ENOENT\n", dir);
621 			d_add(dentry, NULL);
622 			di->lease_shared_gen = ci->i_shared_gen;
623 			return NULL;
624 		}
625 		spin_unlock(&dir->i_lock);
626 	}
627 
628 	op = ceph_snap(dir) == CEPH_SNAPDIR ?
629 		CEPH_MDS_OP_LOOKUPSNAP : CEPH_MDS_OP_LOOKUP;
630 	req = ceph_mdsc_create_request(mdsc, op, USE_ANY_MDS);
631 	if (IS_ERR(req))
632 		return ERR_CAST(req);
633 	req->r_dentry = dget(dentry);
634 	req->r_num_caps = 2;
635 	/* we only need inode linkage */
636 	req->r_args.getattr.mask = cpu_to_le32(CEPH_STAT_CAP_INODE);
637 	req->r_locked_dir = dir;
638 	err = ceph_mdsc_do_request(mdsc, NULL, req);
639 	err = ceph_handle_snapdir(req, dentry, err);
640 	dentry = ceph_finish_lookup(req, dentry, err);
641 	ceph_mdsc_put_request(req);  /* will dput(dentry) */
642 	dout("lookup result=%p\n", dentry);
643 	return dentry;
644 }
645 
646 /*
647  * If we do a create but get no trace back from the MDS, follow up with
648  * a lookup (the VFS expects us to link up the provided dentry).
649  */
650 int ceph_handle_notrace_create(struct inode *dir, struct dentry *dentry)
651 {
652 	struct dentry *result = ceph_lookup(dir, dentry, NULL);
653 
654 	if (result && !IS_ERR(result)) {
655 		/*
656 		 * We created the item, then did a lookup, and found
657 		 * it was already linked to another inode we already
658 		 * had in our cache (and thus got spliced).  Link our
659 		 * dentry to that inode, but don't hash it, just in
660 		 * case the VFS wants to dereference it.
661 		 */
662 		BUG_ON(!result->d_inode);
663 		d_instantiate(dentry, result->d_inode);
664 		return 0;
665 	}
666 	return PTR_ERR(result);
667 }
668 
669 static int ceph_mknod(struct inode *dir, struct dentry *dentry,
670 		      int mode, dev_t rdev)
671 {
672 	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
673 	struct ceph_mds_client *mdsc = fsc->mdsc;
674 	struct ceph_mds_request *req;
675 	int err;
676 
677 	if (ceph_snap(dir) != CEPH_NOSNAP)
678 		return -EROFS;
679 
680 	dout("mknod in dir %p dentry %p mode 0%o rdev %d\n",
681 	     dir, dentry, mode, rdev);
682 	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_MKNOD, USE_AUTH_MDS);
683 	if (IS_ERR(req)) {
684 		d_drop(dentry);
685 		return PTR_ERR(req);
686 	}
687 	req->r_dentry = dget(dentry);
688 	req->r_num_caps = 2;
689 	req->r_locked_dir = dir;
690 	req->r_args.mknod.mode = cpu_to_le32(mode);
691 	req->r_args.mknod.rdev = cpu_to_le32(rdev);
692 	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
693 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
694 	err = ceph_mdsc_do_request(mdsc, dir, req);
695 	if (!err && !req->r_reply_info.head->is_dentry)
696 		err = ceph_handle_notrace_create(dir, dentry);
697 	ceph_mdsc_put_request(req);
698 	if (err)
699 		d_drop(dentry);
700 	return err;
701 }
702 
703 static int ceph_create(struct inode *dir, struct dentry *dentry, int mode,
704 		       struct nameidata *nd)
705 {
706 	dout("create in dir %p dentry %p name '%.*s'\n",
707 	     dir, dentry, dentry->d_name.len, dentry->d_name.name);
708 
709 	if (ceph_snap(dir) != CEPH_NOSNAP)
710 		return -EROFS;
711 
712 	if (nd) {
713 		BUG_ON((nd->flags & LOOKUP_OPEN) == 0);
714 		dentry = ceph_lookup_open(dir, dentry, nd, mode, 0);
715 		/* hrm, what should i do here if we get aliased? */
716 		if (IS_ERR(dentry))
717 			return PTR_ERR(dentry);
718 		return 0;
719 	}
720 
721 	/* fall back to mknod */
722 	return ceph_mknod(dir, dentry, (mode & ~S_IFMT) | S_IFREG, 0);
723 }
724 
725 static int ceph_symlink(struct inode *dir, struct dentry *dentry,
726 			    const char *dest)
727 {
728 	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
729 	struct ceph_mds_client *mdsc = fsc->mdsc;
730 	struct ceph_mds_request *req;
731 	int err;
732 
733 	if (ceph_snap(dir) != CEPH_NOSNAP)
734 		return -EROFS;
735 
736 	dout("symlink in dir %p dentry %p to '%s'\n", dir, dentry, dest);
737 	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SYMLINK, USE_AUTH_MDS);
738 	if (IS_ERR(req)) {
739 		d_drop(dentry);
740 		return PTR_ERR(req);
741 	}
742 	req->r_dentry = dget(dentry);
743 	req->r_num_caps = 2;
744 	req->r_path2 = kstrdup(dest, GFP_NOFS);
745 	req->r_locked_dir = dir;
746 	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
747 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
748 	err = ceph_mdsc_do_request(mdsc, dir, req);
749 	if (!err && !req->r_reply_info.head->is_dentry)
750 		err = ceph_handle_notrace_create(dir, dentry);
751 	ceph_mdsc_put_request(req);
752 	if (err)
753 		d_drop(dentry);
754 	return err;
755 }
756 
757 static int ceph_mkdir(struct inode *dir, struct dentry *dentry, int mode)
758 {
759 	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
760 	struct ceph_mds_client *mdsc = fsc->mdsc;
761 	struct ceph_mds_request *req;
762 	int err = -EROFS;
763 	int op;
764 
765 	if (ceph_snap(dir) == CEPH_SNAPDIR) {
766 		/* mkdir .snap/foo is a MKSNAP */
767 		op = CEPH_MDS_OP_MKSNAP;
768 		dout("mksnap dir %p snap '%.*s' dn %p\n", dir,
769 		     dentry->d_name.len, dentry->d_name.name, dentry);
770 	} else if (ceph_snap(dir) == CEPH_NOSNAP) {
771 		dout("mkdir dir %p dn %p mode 0%o\n", dir, dentry, mode);
772 		op = CEPH_MDS_OP_MKDIR;
773 	} else {
774 		goto out;
775 	}
776 	req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
777 	if (IS_ERR(req)) {
778 		err = PTR_ERR(req);
779 		goto out;
780 	}
781 
782 	req->r_dentry = dget(dentry);
783 	req->r_num_caps = 2;
784 	req->r_locked_dir = dir;
785 	req->r_args.mkdir.mode = cpu_to_le32(mode);
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 < 0)
794 		d_drop(dentry);
795 	return err;
796 }
797 
798 static int ceph_link(struct dentry *old_dentry, struct inode *dir,
799 		     struct dentry *dentry)
800 {
801 	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
802 	struct ceph_mds_client *mdsc = fsc->mdsc;
803 	struct ceph_mds_request *req;
804 	int err;
805 
806 	if (ceph_snap(dir) != CEPH_NOSNAP)
807 		return -EROFS;
808 
809 	dout("link in dir %p old_dentry %p dentry %p\n", dir,
810 	     old_dentry, dentry);
811 	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LINK, USE_AUTH_MDS);
812 	if (IS_ERR(req)) {
813 		d_drop(dentry);
814 		return PTR_ERR(req);
815 	}
816 	req->r_dentry = dget(dentry);
817 	req->r_num_caps = 2;
818 	req->r_old_dentry = dget(old_dentry); /* or inode? hrm. */
819 	req->r_old_dentry_dir = ceph_get_dentry_parent_inode(old_dentry);
820 	req->r_locked_dir = dir;
821 	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
822 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
823 	err = ceph_mdsc_do_request(mdsc, dir, req);
824 	if (err) {
825 		d_drop(dentry);
826 	} else if (!req->r_reply_info.head->is_dentry) {
827 		ihold(old_dentry->d_inode);
828 		d_instantiate(dentry, old_dentry->d_inode);
829 	}
830 	ceph_mdsc_put_request(req);
831 	return err;
832 }
833 
834 /*
835  * For a soon-to-be unlinked file, drop the AUTH_RDCACHE caps.  If it
836  * looks like the link count will hit 0, drop any other caps (other
837  * than PIN) we don't specifically want (due to the file still being
838  * open).
839  */
840 static int drop_caps_for_unlink(struct inode *inode)
841 {
842 	struct ceph_inode_info *ci = ceph_inode(inode);
843 	int drop = CEPH_CAP_LINK_SHARED | CEPH_CAP_LINK_EXCL;
844 
845 	spin_lock(&inode->i_lock);
846 	if (inode->i_nlink == 1) {
847 		drop |= ~(__ceph_caps_wanted(ci) | CEPH_CAP_PIN);
848 		ci->i_ceph_flags |= CEPH_I_NODELAY;
849 	}
850 	spin_unlock(&inode->i_lock);
851 	return drop;
852 }
853 
854 /*
855  * rmdir and unlink are differ only by the metadata op code
856  */
857 static int ceph_unlink(struct inode *dir, struct dentry *dentry)
858 {
859 	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
860 	struct ceph_mds_client *mdsc = fsc->mdsc;
861 	struct inode *inode = dentry->d_inode;
862 	struct ceph_mds_request *req;
863 	int err = -EROFS;
864 	int op;
865 
866 	if (ceph_snap(dir) == CEPH_SNAPDIR) {
867 		/* rmdir .snap/foo is RMSNAP */
868 		dout("rmsnap dir %p '%.*s' dn %p\n", dir, dentry->d_name.len,
869 		     dentry->d_name.name, dentry);
870 		op = CEPH_MDS_OP_RMSNAP;
871 	} else if (ceph_snap(dir) == CEPH_NOSNAP) {
872 		dout("unlink/rmdir dir %p dn %p inode %p\n",
873 		     dir, dentry, inode);
874 		op = ((dentry->d_inode->i_mode & S_IFMT) == S_IFDIR) ?
875 			CEPH_MDS_OP_RMDIR : CEPH_MDS_OP_UNLINK;
876 	} else
877 		goto out;
878 	req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
879 	if (IS_ERR(req)) {
880 		err = PTR_ERR(req);
881 		goto out;
882 	}
883 	req->r_dentry = dget(dentry);
884 	req->r_num_caps = 2;
885 	req->r_locked_dir = dir;
886 	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
887 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
888 	req->r_inode_drop = drop_caps_for_unlink(inode);
889 	err = ceph_mdsc_do_request(mdsc, dir, req);
890 	if (!err && !req->r_reply_info.head->is_dentry)
891 		d_delete(dentry);
892 	ceph_mdsc_put_request(req);
893 out:
894 	return err;
895 }
896 
897 static int ceph_rename(struct inode *old_dir, struct dentry *old_dentry,
898 		       struct inode *new_dir, struct dentry *new_dentry)
899 {
900 	struct ceph_fs_client *fsc = ceph_sb_to_client(old_dir->i_sb);
901 	struct ceph_mds_client *mdsc = fsc->mdsc;
902 	struct ceph_mds_request *req;
903 	int err;
904 
905 	if (ceph_snap(old_dir) != ceph_snap(new_dir))
906 		return -EXDEV;
907 	if (ceph_snap(old_dir) != CEPH_NOSNAP ||
908 	    ceph_snap(new_dir) != CEPH_NOSNAP)
909 		return -EROFS;
910 	dout("rename dir %p dentry %p to dir %p dentry %p\n",
911 	     old_dir, old_dentry, new_dir, new_dentry);
912 	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_RENAME, USE_AUTH_MDS);
913 	if (IS_ERR(req))
914 		return PTR_ERR(req);
915 	req->r_dentry = dget(new_dentry);
916 	req->r_num_caps = 2;
917 	req->r_old_dentry = dget(old_dentry);
918 	req->r_old_dentry_dir = ceph_get_dentry_parent_inode(old_dentry);
919 	req->r_locked_dir = new_dir;
920 	req->r_old_dentry_drop = CEPH_CAP_FILE_SHARED;
921 	req->r_old_dentry_unless = CEPH_CAP_FILE_EXCL;
922 	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
923 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
924 	/* release LINK_RDCACHE on source inode (mds will lock it) */
925 	req->r_old_inode_drop = CEPH_CAP_LINK_SHARED;
926 	if (new_dentry->d_inode)
927 		req->r_inode_drop = drop_caps_for_unlink(new_dentry->d_inode);
928 	err = ceph_mdsc_do_request(mdsc, old_dir, req);
929 	if (!err && !req->r_reply_info.head->is_dentry) {
930 		/*
931 		 * Normally d_move() is done by fill_trace (called by
932 		 * do_request, above).  If there is no trace, we need
933 		 * to do it here.
934 		 */
935 
936 		/* d_move screws up d_subdirs order */
937 		ceph_i_clear(new_dir, CEPH_I_COMPLETE);
938 
939 		d_move(old_dentry, new_dentry);
940 
941 		/* ensure target dentry is invalidated, despite
942 		   rehashing bug in vfs_rename_dir */
943 		ceph_invalidate_dentry_lease(new_dentry);
944 	}
945 	ceph_mdsc_put_request(req);
946 	return err;
947 }
948 
949 /*
950  * Ensure a dentry lease will no longer revalidate.
951  */
952 void ceph_invalidate_dentry_lease(struct dentry *dentry)
953 {
954 	spin_lock(&dentry->d_lock);
955 	dentry->d_time = jiffies;
956 	ceph_dentry(dentry)->lease_shared_gen = 0;
957 	spin_unlock(&dentry->d_lock);
958 }
959 
960 /*
961  * Check if dentry lease is valid.  If not, delete the lease.  Try to
962  * renew if the least is more than half up.
963  */
964 static int dentry_lease_is_valid(struct dentry *dentry)
965 {
966 	struct ceph_dentry_info *di;
967 	struct ceph_mds_session *s;
968 	int valid = 0;
969 	u32 gen;
970 	unsigned long ttl;
971 	struct ceph_mds_session *session = NULL;
972 	struct inode *dir = NULL;
973 	u32 seq = 0;
974 
975 	spin_lock(&dentry->d_lock);
976 	di = ceph_dentry(dentry);
977 	if (di && di->lease_session) {
978 		s = di->lease_session;
979 		spin_lock(&s->s_cap_lock);
980 		gen = s->s_cap_gen;
981 		ttl = s->s_cap_ttl;
982 		spin_unlock(&s->s_cap_lock);
983 
984 		if (di->lease_gen == gen &&
985 		    time_before(jiffies, dentry->d_time) &&
986 		    time_before(jiffies, ttl)) {
987 			valid = 1;
988 			if (di->lease_renew_after &&
989 			    time_after(jiffies, di->lease_renew_after)) {
990 				/* we should renew */
991 				dir = dentry->d_parent->d_inode;
992 				session = ceph_get_mds_session(s);
993 				seq = di->lease_seq;
994 				di->lease_renew_after = 0;
995 				di->lease_renew_from = jiffies;
996 			}
997 		}
998 	}
999 	spin_unlock(&dentry->d_lock);
1000 
1001 	if (session) {
1002 		ceph_mdsc_lease_send_msg(session, dir, dentry,
1003 					 CEPH_MDS_LEASE_RENEW, seq);
1004 		ceph_put_mds_session(session);
1005 	}
1006 	dout("dentry_lease_is_valid - dentry %p = %d\n", dentry, valid);
1007 	return valid;
1008 }
1009 
1010 /*
1011  * Check if directory-wide content lease/cap is valid.
1012  */
1013 static int dir_lease_is_valid(struct inode *dir, struct dentry *dentry)
1014 {
1015 	struct ceph_inode_info *ci = ceph_inode(dir);
1016 	struct ceph_dentry_info *di = ceph_dentry(dentry);
1017 	int valid = 0;
1018 
1019 	spin_lock(&dir->i_lock);
1020 	if (ci->i_shared_gen == di->lease_shared_gen)
1021 		valid = __ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1);
1022 	spin_unlock(&dir->i_lock);
1023 	dout("dir_lease_is_valid dir %p v%u dentry %p v%u = %d\n",
1024 	     dir, (unsigned)ci->i_shared_gen, dentry,
1025 	     (unsigned)di->lease_shared_gen, valid);
1026 	return valid;
1027 }
1028 
1029 /*
1030  * Check if cached dentry can be trusted.
1031  */
1032 static int ceph_d_revalidate(struct dentry *dentry, struct nameidata *nd)
1033 {
1034 	int valid = 0;
1035 	struct inode *dir;
1036 
1037 	if (nd && nd->flags & LOOKUP_RCU)
1038 		return -ECHILD;
1039 
1040 	dout("d_revalidate %p '%.*s' inode %p offset %lld\n", dentry,
1041 	     dentry->d_name.len, dentry->d_name.name, dentry->d_inode,
1042 	     ceph_dentry(dentry)->offset);
1043 
1044 	dir = ceph_get_dentry_parent_inode(dentry);
1045 
1046 	/* always trust cached snapped dentries, snapdir dentry */
1047 	if (ceph_snap(dir) != CEPH_NOSNAP) {
1048 		dout("d_revalidate %p '%.*s' inode %p is SNAPPED\n", dentry,
1049 		     dentry->d_name.len, dentry->d_name.name, dentry->d_inode);
1050 		valid = 1;
1051 	} else if (dentry->d_inode &&
1052 		   ceph_snap(dentry->d_inode) == CEPH_SNAPDIR) {
1053 		valid = 1;
1054 	} else if (dentry_lease_is_valid(dentry) ||
1055 		   dir_lease_is_valid(dir, dentry)) {
1056 		valid = 1;
1057 	}
1058 
1059 	dout("d_revalidate %p %s\n", dentry, valid ? "valid" : "invalid");
1060 	if (valid)
1061 		ceph_dentry_lru_touch(dentry);
1062 	else
1063 		d_drop(dentry);
1064 	iput(dir);
1065 	return valid;
1066 }
1067 
1068 /*
1069  * Release our ceph_dentry_info.
1070  */
1071 static void ceph_d_release(struct dentry *dentry)
1072 {
1073 	struct ceph_dentry_info *di = ceph_dentry(dentry);
1074 
1075 	dout("d_release %p\n", dentry);
1076 	if (di) {
1077 		ceph_dentry_lru_del(dentry);
1078 		if (di->lease_session)
1079 			ceph_put_mds_session(di->lease_session);
1080 		kmem_cache_free(ceph_dentry_cachep, di);
1081 		dentry->d_fsdata = NULL;
1082 	}
1083 }
1084 
1085 static int ceph_snapdir_d_revalidate(struct dentry *dentry,
1086 					  struct nameidata *nd)
1087 {
1088 	/*
1089 	 * Eventually, we'll want to revalidate snapped metadata
1090 	 * too... probably...
1091 	 */
1092 	return 1;
1093 }
1094 
1095 
1096 
1097 /*
1098  * read() on a dir.  This weird interface hack only works if mounted
1099  * with '-o dirstat'.
1100  */
1101 static ssize_t ceph_read_dir(struct file *file, char __user *buf, size_t size,
1102 			     loff_t *ppos)
1103 {
1104 	struct ceph_file_info *cf = file->private_data;
1105 	struct inode *inode = file->f_dentry->d_inode;
1106 	struct ceph_inode_info *ci = ceph_inode(inode);
1107 	int left;
1108 	const int bufsize = 1024;
1109 
1110 	if (!ceph_test_mount_opt(ceph_sb_to_client(inode->i_sb), DIRSTAT))
1111 		return -EISDIR;
1112 
1113 	if (!cf->dir_info) {
1114 		cf->dir_info = kmalloc(bufsize, GFP_NOFS);
1115 		if (!cf->dir_info)
1116 			return -ENOMEM;
1117 		cf->dir_info_len =
1118 			snprintf(cf->dir_info, bufsize,
1119 				"entries:   %20lld\n"
1120 				" files:    %20lld\n"
1121 				" subdirs:  %20lld\n"
1122 				"rentries:  %20lld\n"
1123 				" rfiles:   %20lld\n"
1124 				" rsubdirs: %20lld\n"
1125 				"rbytes:    %20lld\n"
1126 				"rctime:    %10ld.%09ld\n",
1127 				ci->i_files + ci->i_subdirs,
1128 				ci->i_files,
1129 				ci->i_subdirs,
1130 				ci->i_rfiles + ci->i_rsubdirs,
1131 				ci->i_rfiles,
1132 				ci->i_rsubdirs,
1133 				ci->i_rbytes,
1134 				(long)ci->i_rctime.tv_sec,
1135 				(long)ci->i_rctime.tv_nsec);
1136 	}
1137 
1138 	if (*ppos >= cf->dir_info_len)
1139 		return 0;
1140 	size = min_t(unsigned, size, cf->dir_info_len-*ppos);
1141 	left = copy_to_user(buf, cf->dir_info + *ppos, size);
1142 	if (left == size)
1143 		return -EFAULT;
1144 	*ppos += (size - left);
1145 	return size - left;
1146 }
1147 
1148 /*
1149  * an fsync() on a dir will wait for any uncommitted directory
1150  * operations to commit.
1151  */
1152 static int ceph_dir_fsync(struct file *file, loff_t start, loff_t end,
1153 			  int datasync)
1154 {
1155 	struct inode *inode = file->f_path.dentry->d_inode;
1156 	struct ceph_inode_info *ci = ceph_inode(inode);
1157 	struct list_head *head = &ci->i_unsafe_dirops;
1158 	struct ceph_mds_request *req;
1159 	u64 last_tid;
1160 	int ret = 0;
1161 
1162 	dout("dir_fsync %p\n", inode);
1163 	ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
1164 	if (ret)
1165 		return ret;
1166 	mutex_lock(&inode->i_mutex);
1167 
1168 	spin_lock(&ci->i_unsafe_lock);
1169 	if (list_empty(head))
1170 		goto out;
1171 
1172 	req = list_entry(head->prev,
1173 			 struct ceph_mds_request, r_unsafe_dir_item);
1174 	last_tid = req->r_tid;
1175 
1176 	do {
1177 		ceph_mdsc_get_request(req);
1178 		spin_unlock(&ci->i_unsafe_lock);
1179 		dout("dir_fsync %p wait on tid %llu (until %llu)\n",
1180 		     inode, req->r_tid, last_tid);
1181 		if (req->r_timeout) {
1182 			ret = wait_for_completion_timeout(
1183 				&req->r_safe_completion, req->r_timeout);
1184 			if (ret > 0)
1185 				ret = 0;
1186 			else if (ret == 0)
1187 				ret = -EIO;  /* timed out */
1188 		} else {
1189 			wait_for_completion(&req->r_safe_completion);
1190 		}
1191 		spin_lock(&ci->i_unsafe_lock);
1192 		ceph_mdsc_put_request(req);
1193 
1194 		if (ret || list_empty(head))
1195 			break;
1196 		req = list_entry(head->next,
1197 				 struct ceph_mds_request, r_unsafe_dir_item);
1198 	} while (req->r_tid < last_tid);
1199 out:
1200 	spin_unlock(&ci->i_unsafe_lock);
1201 	mutex_unlock(&inode->i_mutex);
1202 
1203 	return ret;
1204 }
1205 
1206 /*
1207  * We maintain a private dentry LRU.
1208  *
1209  * FIXME: this needs to be changed to a per-mds lru to be useful.
1210  */
1211 void ceph_dentry_lru_add(struct dentry *dn)
1212 {
1213 	struct ceph_dentry_info *di = ceph_dentry(dn);
1214 	struct ceph_mds_client *mdsc;
1215 
1216 	dout("dentry_lru_add %p %p '%.*s'\n", di, dn,
1217 	     dn->d_name.len, dn->d_name.name);
1218 	if (di) {
1219 		mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
1220 		spin_lock(&mdsc->dentry_lru_lock);
1221 		list_add_tail(&di->lru, &mdsc->dentry_lru);
1222 		mdsc->num_dentry++;
1223 		spin_unlock(&mdsc->dentry_lru_lock);
1224 	}
1225 }
1226 
1227 void ceph_dentry_lru_touch(struct dentry *dn)
1228 {
1229 	struct ceph_dentry_info *di = ceph_dentry(dn);
1230 	struct ceph_mds_client *mdsc;
1231 
1232 	dout("dentry_lru_touch %p %p '%.*s' (offset %lld)\n", di, dn,
1233 	     dn->d_name.len, dn->d_name.name, di->offset);
1234 	if (di) {
1235 		mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
1236 		spin_lock(&mdsc->dentry_lru_lock);
1237 		list_move_tail(&di->lru, &mdsc->dentry_lru);
1238 		spin_unlock(&mdsc->dentry_lru_lock);
1239 	}
1240 }
1241 
1242 void ceph_dentry_lru_del(struct dentry *dn)
1243 {
1244 	struct ceph_dentry_info *di = ceph_dentry(dn);
1245 	struct ceph_mds_client *mdsc;
1246 
1247 	dout("dentry_lru_del %p %p '%.*s'\n", di, dn,
1248 	     dn->d_name.len, dn->d_name.name);
1249 	if (di) {
1250 		mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
1251 		spin_lock(&mdsc->dentry_lru_lock);
1252 		list_del_init(&di->lru);
1253 		mdsc->num_dentry--;
1254 		spin_unlock(&mdsc->dentry_lru_lock);
1255 	}
1256 }
1257 
1258 /*
1259  * Return name hash for a given dentry.  This is dependent on
1260  * the parent directory's hash function.
1261  */
1262 unsigned ceph_dentry_hash(struct inode *dir, struct dentry *dn)
1263 {
1264 	struct ceph_inode_info *dci = ceph_inode(dir);
1265 
1266 	switch (dci->i_dir_layout.dl_dir_hash) {
1267 	case 0:	/* for backward compat */
1268 	case CEPH_STR_HASH_LINUX:
1269 		return dn->d_name.hash;
1270 
1271 	default:
1272 		return ceph_str_hash(dci->i_dir_layout.dl_dir_hash,
1273 				     dn->d_name.name, dn->d_name.len);
1274 	}
1275 }
1276 
1277 const struct file_operations ceph_dir_fops = {
1278 	.read = ceph_read_dir,
1279 	.readdir = ceph_readdir,
1280 	.llseek = ceph_dir_llseek,
1281 	.open = ceph_open,
1282 	.release = ceph_release,
1283 	.unlocked_ioctl = ceph_ioctl,
1284 	.fsync = ceph_dir_fsync,
1285 };
1286 
1287 const struct inode_operations ceph_dir_iops = {
1288 	.lookup = ceph_lookup,
1289 	.permission = ceph_permission,
1290 	.getattr = ceph_getattr,
1291 	.setattr = ceph_setattr,
1292 	.setxattr = ceph_setxattr,
1293 	.getxattr = ceph_getxattr,
1294 	.listxattr = ceph_listxattr,
1295 	.removexattr = ceph_removexattr,
1296 	.mknod = ceph_mknod,
1297 	.symlink = ceph_symlink,
1298 	.mkdir = ceph_mkdir,
1299 	.link = ceph_link,
1300 	.unlink = ceph_unlink,
1301 	.rmdir = ceph_unlink,
1302 	.rename = ceph_rename,
1303 	.create = ceph_create,
1304 };
1305 
1306 const struct dentry_operations ceph_dentry_ops = {
1307 	.d_revalidate = ceph_d_revalidate,
1308 	.d_release = ceph_d_release,
1309 };
1310 
1311 const struct dentry_operations ceph_snapdir_dentry_ops = {
1312 	.d_revalidate = ceph_snapdir_d_revalidate,
1313 	.d_release = ceph_d_release,
1314 };
1315 
1316 const struct dentry_operations ceph_snap_dentry_ops = {
1317 	.d_release = ceph_d_release,
1318 };
1319