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1#include <linux/ceph/ceph_debug.h>
2
3#include <linux/sort.h>
4#include <linux/slab.h>
5
6#include "super.h"
7#include "mds_client.h"
8
9#include <linux/ceph/decode.h>
10
11/*
12 * Snapshots in ceph are driven in large part by cooperation from the
13 * client. In contrast to local file systems or file servers that
14 * implement snapshots at a single point in the system, ceph's
15 * distributed access to storage requires clients to help decide
16 * whether a write logically occurs before or after a recently created
17 * snapshot.
18 *
19 * This provides a perfect instantanous client-wide snapshot. Between
20 * clients, however, snapshots may appear to be applied at slightly
21 * different points in time, depending on delays in delivering the
22 * snapshot notification.
23 *
24 * Snapshots are _not_ file system-wide. Instead, each snapshot
25 * applies to the subdirectory nested beneath some directory. This
26 * effectively divides the hierarchy into multiple "realms," where all
27 * of the files contained by each realm share the same set of
28 * snapshots. An individual realm's snap set contains snapshots
29 * explicitly created on that realm, as well as any snaps in its
30 * parent's snap set _after_ the point at which the parent became it's
31 * parent (due to, say, a rename). Similarly, snaps from prior parents
32 * during the time intervals during which they were the parent are included.
33 *
34 * The client is spared most of this detail, fortunately... it must only
35 * maintains a hierarchy of realms reflecting the current parent/child
36 * realm relationship, and for each realm has an explicit list of snaps
37 * inherited from prior parents.
38 *
39 * A snap_realm struct is maintained for realms containing every inode
40 * with an open cap in the system. (The needed snap realm information is
41 * provided by the MDS whenever a cap is issued, i.e., on open.) A 'seq'
42 * version number is used to ensure that as realm parameters change (new
43 * snapshot, new parent, etc.) the client's realm hierarchy is updated.
44 *
45 * The realm hierarchy drives the generation of a 'snap context' for each
46 * realm, which simply lists the resulting set of snaps for the realm. This
47 * is attached to any writes sent to OSDs.
48 */
49/*
50 * Unfortunately error handling is a bit mixed here. If we get a snap
51 * update, but don't have enough memory to update our realm hierarchy,
52 * it's not clear what we can do about it (besides complaining to the
53 * console).
54 */
55
56
57/*
58 * increase ref count for the realm
59 *
60 * caller must hold snap_rwsem for write.
61 */
62void ceph_get_snap_realm(struct ceph_mds_client *mdsc,
63 struct ceph_snap_realm *realm)
64{
65 dout("get_realm %p %d -> %d\n", realm,
66 atomic_read(&realm->nref), atomic_read(&realm->nref)+1);
67 /*
68 * since we _only_ increment realm refs or empty the empty
69 * list with snap_rwsem held, adjusting the empty list here is
70 * safe. we do need to protect against concurrent empty list
71 * additions, however.
72 */
73 if (atomic_read(&realm->nref) == 0) {
74 spin_lock(&mdsc->snap_empty_lock);
75 list_del_init(&realm->empty_item);
76 spin_unlock(&mdsc->snap_empty_lock);
77 }
78
79 atomic_inc(&realm->nref);
80}
81
82static void __insert_snap_realm(struct rb_root *root,
83 struct ceph_snap_realm *new)
84{
85 struct rb_node **p = &root->rb_node;
86 struct rb_node *parent = NULL;
87 struct ceph_snap_realm *r = NULL;
88
89 while (*p) {
90 parent = *p;
91 r = rb_entry(parent, struct ceph_snap_realm, node);
92 if (new->ino < r->ino)
93 p = &(*p)->rb_left;
94 else if (new->ino > r->ino)
95 p = &(*p)->rb_right;
96 else
97 BUG();
98 }
99
100 rb_link_node(&new->node, parent, p);
101 rb_insert_color(&new->node, root);
102}
103
104/*
105 * create and get the realm rooted at @ino and bump its ref count.
106 *
107 * caller must hold snap_rwsem for write.
108 */
109static struct ceph_snap_realm *ceph_create_snap_realm(
110 struct ceph_mds_client *mdsc,
111 u64 ino)
112{
113 struct ceph_snap_realm *realm;
114
115 realm = kzalloc(sizeof(*realm), GFP_NOFS);
116 if (!realm)
117 return ERR_PTR(-ENOMEM);
118
119 atomic_set(&realm->nref, 0); /* tree does not take a ref */
120 realm->ino = ino;
121 INIT_LIST_HEAD(&realm->children);
122 INIT_LIST_HEAD(&realm->child_item);
123 INIT_LIST_HEAD(&realm->empty_item);
124 INIT_LIST_HEAD(&realm->dirty_item);
125 INIT_LIST_HEAD(&realm->inodes_with_caps);
126 spin_lock_init(&realm->inodes_with_caps_lock);
127 __insert_snap_realm(&mdsc->snap_realms, realm);
128 dout("create_snap_realm %llx %p\n", realm->ino, realm);
129 return realm;
130}
131
132/*
133 * lookup the realm rooted at @ino.
134 *
135 * caller must hold snap_rwsem for write.
136 */
137struct ceph_snap_realm *ceph_lookup_snap_realm(struct ceph_mds_client *mdsc,
138 u64 ino)
139{
140 struct rb_node *n = mdsc->snap_realms.rb_node;
141 struct ceph_snap_realm *r;
142
143 while (n) {
144 r = rb_entry(n, struct ceph_snap_realm, node);
145 if (ino < r->ino)
146 n = n->rb_left;
147 else if (ino > r->ino)
148 n = n->rb_right;
149 else {
150 dout("lookup_snap_realm %llx %p\n", r->ino, r);
151 return r;
152 }
153 }
154 return NULL;
155}
156
157static void __put_snap_realm(struct ceph_mds_client *mdsc,
158 struct ceph_snap_realm *realm);
159
160/*
161 * called with snap_rwsem (write)
162 */
163static void __destroy_snap_realm(struct ceph_mds_client *mdsc,
164 struct ceph_snap_realm *realm)
165{
166 dout("__destroy_snap_realm %p %llx\n", realm, realm->ino);
167
168 rb_erase(&realm->node, &mdsc->snap_realms);
169
170 if (realm->parent) {
171 list_del_init(&realm->child_item);
172 __put_snap_realm(mdsc, realm->parent);
173 }
174
175 kfree(realm->prior_parent_snaps);
176 kfree(realm->snaps);
177 ceph_put_snap_context(realm->cached_context);
178 kfree(realm);
179}
180
181/*
182 * caller holds snap_rwsem (write)
183 */
184static void __put_snap_realm(struct ceph_mds_client *mdsc,
185 struct ceph_snap_realm *realm)
186{
187 dout("__put_snap_realm %llx %p %d -> %d\n", realm->ino, realm,
188 atomic_read(&realm->nref), atomic_read(&realm->nref)-1);
189 if (atomic_dec_and_test(&realm->nref))
190 __destroy_snap_realm(mdsc, realm);
191}
192
193/*
194 * caller needn't hold any locks
195 */
196void ceph_put_snap_realm(struct ceph_mds_client *mdsc,
197 struct ceph_snap_realm *realm)
198{
199 dout("put_snap_realm %llx %p %d -> %d\n", realm->ino, realm,
200 atomic_read(&realm->nref), atomic_read(&realm->nref)-1);
201 if (!atomic_dec_and_test(&realm->nref))
202 return;
203
204 if (down_write_trylock(&mdsc->snap_rwsem)) {
205 __destroy_snap_realm(mdsc, realm);
206 up_write(&mdsc->snap_rwsem);
207 } else {
208 spin_lock(&mdsc->snap_empty_lock);
209 list_add(&realm->empty_item, &mdsc->snap_empty);
210 spin_unlock(&mdsc->snap_empty_lock);
211 }
212}
213
214/*
215 * Clean up any realms whose ref counts have dropped to zero. Note
216 * that this does not include realms who were created but not yet
217 * used.
218 *
219 * Called under snap_rwsem (write)
220 */
221static void __cleanup_empty_realms(struct ceph_mds_client *mdsc)
222{
223 struct ceph_snap_realm *realm;
224
225 spin_lock(&mdsc->snap_empty_lock);
226 while (!list_empty(&mdsc->snap_empty)) {
227 realm = list_first_entry(&mdsc->snap_empty,
228 struct ceph_snap_realm, empty_item);
229 list_del(&realm->empty_item);
230 spin_unlock(&mdsc->snap_empty_lock);
231 __destroy_snap_realm(mdsc, realm);
232 spin_lock(&mdsc->snap_empty_lock);
233 }
234 spin_unlock(&mdsc->snap_empty_lock);
235}
236
237void ceph_cleanup_empty_realms(struct ceph_mds_client *mdsc)
238{
239 down_write(&mdsc->snap_rwsem);
240 __cleanup_empty_realms(mdsc);
241 up_write(&mdsc->snap_rwsem);
242}
243
244/*
245 * adjust the parent realm of a given @realm. adjust child list, and parent
246 * pointers, and ref counts appropriately.
247 *
248 * return true if parent was changed, 0 if unchanged, <0 on error.
249 *
250 * caller must hold snap_rwsem for write.
251 */
252static int adjust_snap_realm_parent(struct ceph_mds_client *mdsc,
253 struct ceph_snap_realm *realm,
254 u64 parentino)
255{
256 struct ceph_snap_realm *parent;
257
258 if (realm->parent_ino == parentino)
259 return 0;
260
261 parent = ceph_lookup_snap_realm(mdsc, parentino);
262 if (!parent) {
263 parent = ceph_create_snap_realm(mdsc, parentino);
264 if (IS_ERR(parent))
265 return PTR_ERR(parent);
266 }
267 dout("adjust_snap_realm_parent %llx %p: %llx %p -> %llx %p\n",
268 realm->ino, realm, realm->parent_ino, realm->parent,
269 parentino, parent);
270 if (realm->parent) {
271 list_del_init(&realm->child_item);
272 ceph_put_snap_realm(mdsc, realm->parent);
273 }
274 realm->parent_ino = parentino;
275 realm->parent = parent;
276 ceph_get_snap_realm(mdsc, parent);
277 list_add(&realm->child_item, &parent->children);
278 return 1;
279}
280
281
282static int cmpu64_rev(const void *a, const void *b)
283{
284 if (*(u64 *)a < *(u64 *)b)
285 return 1;
286 if (*(u64 *)a > *(u64 *)b)
287 return -1;
288 return 0;
289}
290
291/*
292 * build the snap context for a given realm.
293 */
294static int build_snap_context(struct ceph_snap_realm *realm)
295{
296 struct ceph_snap_realm *parent = realm->parent;
297 struct ceph_snap_context *snapc;
298 int err = 0;
299 u32 num = realm->num_prior_parent_snaps + realm->num_snaps;
300
301 /*
302 * build parent context, if it hasn't been built.
303 * conservatively estimate that all parent snaps might be
304 * included by us.
305 */
306 if (parent) {
307 if (!parent->cached_context) {
308 err = build_snap_context(parent);
309 if (err)
310 goto fail;
311 }
312 num += parent->cached_context->num_snaps;
313 }
314
315 /* do i actually need to update? not if my context seq
316 matches realm seq, and my parents' does to. (this works
317 because we rebuild_snap_realms() works _downward_ in
318 hierarchy after each update.) */
319 if (realm->cached_context &&
320 realm->cached_context->seq == realm->seq &&
321 (!parent ||
322 realm->cached_context->seq >= parent->cached_context->seq)) {
323 dout("build_snap_context %llx %p: %p seq %lld (%u snaps)"
324 " (unchanged)\n",
325 realm->ino, realm, realm->cached_context,
326 realm->cached_context->seq,
327 (unsigned int) realm->cached_context->num_snaps);
328 return 0;
329 }
330
331 /* alloc new snap context */
332 err = -ENOMEM;
333 if (num > (SIZE_MAX - sizeof(*snapc)) / sizeof(u64))
334 goto fail;
335 snapc = ceph_create_snap_context(num, GFP_NOFS);
336 if (!snapc)
337 goto fail;
338
339 /* build (reverse sorted) snap vector */
340 num = 0;
341 snapc->seq = realm->seq;
342 if (parent) {
343 u32 i;
344
345 /* include any of parent's snaps occurring _after_ my
346 parent became my parent */
347 for (i = 0; i < parent->cached_context->num_snaps; i++)
348 if (parent->cached_context->snaps[i] >=
349 realm->parent_since)
350 snapc->snaps[num++] =
351 parent->cached_context->snaps[i];
352 if (parent->cached_context->seq > snapc->seq)
353 snapc->seq = parent->cached_context->seq;
354 }
355 memcpy(snapc->snaps + num, realm->snaps,
356 sizeof(u64)*realm->num_snaps);
357 num += realm->num_snaps;
358 memcpy(snapc->snaps + num, realm->prior_parent_snaps,
359 sizeof(u64)*realm->num_prior_parent_snaps);
360 num += realm->num_prior_parent_snaps;
361
362 sort(snapc->snaps, num, sizeof(u64), cmpu64_rev, NULL);
363 snapc->num_snaps = num;
364 dout("build_snap_context %llx %p: %p seq %lld (%u snaps)\n",
365 realm->ino, realm, snapc, snapc->seq,
366 (unsigned int) snapc->num_snaps);
367
368 if (realm->cached_context)
369 ceph_put_snap_context(realm->cached_context);
370 realm->cached_context = snapc;
371 return 0;
372
373fail:
374 /*
375 * if we fail, clear old (incorrect) cached_context... hopefully
376 * we'll have better luck building it later
377 */
378 if (realm->cached_context) {
379 ceph_put_snap_context(realm->cached_context);
380 realm->cached_context = NULL;
381 }
382 pr_err("build_snap_context %llx %p fail %d\n", realm->ino,
383 realm, err);
384 return err;
385}
386
387/*
388 * rebuild snap context for the given realm and all of its children.
389 */
390static void rebuild_snap_realms(struct ceph_snap_realm *realm)
391{
392 struct ceph_snap_realm *child;
393
394 dout("rebuild_snap_realms %llx %p\n", realm->ino, realm);
395 build_snap_context(realm);
396
397 list_for_each_entry(child, &realm->children, child_item)
398 rebuild_snap_realms(child);
399}
400
401
402/*
403 * helper to allocate and decode an array of snapids. free prior
404 * instance, if any.
405 */
406static int dup_array(u64 **dst, __le64 *src, u32 num)
407{
408 u32 i;
409
410 kfree(*dst);
411 if (num) {
412 *dst = kcalloc(num, sizeof(u64), GFP_NOFS);
413 if (!*dst)
414 return -ENOMEM;
415 for (i = 0; i < num; i++)
416 (*dst)[i] = get_unaligned_le64(src + i);
417 } else {
418 *dst = NULL;
419 }
420 return 0;
421}
422
423
424/*
425 * When a snapshot is applied, the size/mtime inode metadata is queued
426 * in a ceph_cap_snap (one for each snapshot) until writeback
427 * completes and the metadata can be flushed back to the MDS.
428 *
429 * However, if a (sync) write is currently in-progress when we apply
430 * the snapshot, we have to wait until the write succeeds or fails
431 * (and a final size/mtime is known). In this case the
432 * cap_snap->writing = 1, and is said to be "pending." When the write
433 * finishes, we __ceph_finish_cap_snap().
434 *
435 * Caller must hold snap_rwsem for read (i.e., the realm topology won't
436 * change).
437 */
438void ceph_queue_cap_snap(struct ceph_inode_info *ci)
439{
440 struct inode *inode = &ci->vfs_inode;
441 struct ceph_cap_snap *capsnap;
442 int used, dirty;
443
444 capsnap = kzalloc(sizeof(*capsnap), GFP_NOFS);
445 if (!capsnap) {
446 pr_err("ENOMEM allocating ceph_cap_snap on %p\n", inode);
447 return;
448 }
449
450 spin_lock(&ci->i_ceph_lock);
451 used = __ceph_caps_used(ci);
452 dirty = __ceph_caps_dirty(ci);
453
454 /*
455 * If there is a write in progress, treat that as a dirty Fw,
456 * even though it hasn't completed yet; by the time we finish
457 * up this capsnap it will be.
458 */
459 if (used & CEPH_CAP_FILE_WR)
460 dirty |= CEPH_CAP_FILE_WR;
461
462 if (__ceph_have_pending_cap_snap(ci)) {
463 /* there is no point in queuing multiple "pending" cap_snaps,
464 as no new writes are allowed to start when pending, so any
465 writes in progress now were started before the previous
466 cap_snap. lucky us. */
467 dout("queue_cap_snap %p already pending\n", inode);
468 kfree(capsnap);
469 } else if (dirty & (CEPH_CAP_AUTH_EXCL|CEPH_CAP_XATTR_EXCL|
470 CEPH_CAP_FILE_EXCL|CEPH_CAP_FILE_WR)) {
471 struct ceph_snap_context *snapc = ci->i_head_snapc;
472
473 /*
474 * if we are a sync write, we may need to go to the snaprealm
475 * to get the current snapc.
476 */
477 if (!snapc)
478 snapc = ci->i_snap_realm->cached_context;
479
480 dout("queue_cap_snap %p cap_snap %p queuing under %p %s\n",
481 inode, capsnap, snapc, ceph_cap_string(dirty));
482 ihold(inode);
483
484 atomic_set(&capsnap->nref, 1);
485 capsnap->ci = ci;
486 INIT_LIST_HEAD(&capsnap->ci_item);
487 INIT_LIST_HEAD(&capsnap->flushing_item);
488
489 capsnap->follows = snapc->seq;
490 capsnap->issued = __ceph_caps_issued(ci, NULL);
491 capsnap->dirty = dirty;
492
493 capsnap->mode = inode->i_mode;
494 capsnap->uid = inode->i_uid;
495 capsnap->gid = inode->i_gid;
496
497 if (dirty & CEPH_CAP_XATTR_EXCL) {
498 __ceph_build_xattrs_blob(ci);
499 capsnap->xattr_blob =
500 ceph_buffer_get(ci->i_xattrs.blob);
501 capsnap->xattr_version = ci->i_xattrs.version;
502 } else {
503 capsnap->xattr_blob = NULL;
504 capsnap->xattr_version = 0;
505 }
506
507 /* dirty page count moved from _head to this cap_snap;
508 all subsequent writes page dirties occur _after_ this
509 snapshot. */
510 capsnap->dirty_pages = ci->i_wrbuffer_ref_head;
511 ci->i_wrbuffer_ref_head = 0;
512 capsnap->context = snapc;
513 ci->i_head_snapc =
514 ceph_get_snap_context(ci->i_snap_realm->cached_context);
515 dout(" new snapc is %p\n", ci->i_head_snapc);
516 list_add_tail(&capsnap->ci_item, &ci->i_cap_snaps);
517
518 if (used & CEPH_CAP_FILE_WR) {
519 dout("queue_cap_snap %p cap_snap %p snapc %p"
520 " seq %llu used WR, now pending\n", inode,
521 capsnap, snapc, snapc->seq);
522 capsnap->writing = 1;
523 } else {
524 /* note mtime, size NOW. */
525 __ceph_finish_cap_snap(ci, capsnap);
526 }
527 } else {
528 dout("queue_cap_snap %p nothing dirty|writing\n", inode);
529 kfree(capsnap);
530 }
531
532 spin_unlock(&ci->i_ceph_lock);
533}
534
535/*
536 * Finalize the size, mtime for a cap_snap.. that is, settle on final values
537 * to be used for the snapshot, to be flushed back to the mds.
538 *
539 * If capsnap can now be flushed, add to snap_flush list, and return 1.
540 *
541 * Caller must hold i_ceph_lock.
542 */
543int __ceph_finish_cap_snap(struct ceph_inode_info *ci,
544 struct ceph_cap_snap *capsnap)
545{
546 struct inode *inode = &ci->vfs_inode;
547 struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
548
549 BUG_ON(capsnap->writing);
550 capsnap->size = inode->i_size;
551 capsnap->mtime = inode->i_mtime;
552 capsnap->atime = inode->i_atime;
553 capsnap->ctime = inode->i_ctime;
554 capsnap->time_warp_seq = ci->i_time_warp_seq;
555 if (capsnap->dirty_pages) {
556 dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu "
557 "still has %d dirty pages\n", inode, capsnap,
558 capsnap->context, capsnap->context->seq,
559 ceph_cap_string(capsnap->dirty), capsnap->size,
560 capsnap->dirty_pages);
561 return 0;
562 }
563 dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu\n",
564 inode, capsnap, capsnap->context,
565 capsnap->context->seq, ceph_cap_string(capsnap->dirty),
566 capsnap->size);
567
568 spin_lock(&mdsc->snap_flush_lock);
569 list_add_tail(&ci->i_snap_flush_item, &mdsc->snap_flush_list);
570 spin_unlock(&mdsc->snap_flush_lock);
571 return 1; /* caller may want to ceph_flush_snaps */
572}
573
574/*
575 * Queue cap_snaps for snap writeback for this realm and its children.
576 * Called under snap_rwsem, so realm topology won't change.
577 */
578static void queue_realm_cap_snaps(struct ceph_snap_realm *realm)
579{
580 struct ceph_inode_info *ci;
581 struct inode *lastinode = NULL;
582 struct ceph_snap_realm *child;
583
584 dout("queue_realm_cap_snaps %p %llx inodes\n", realm, realm->ino);
585
586 spin_lock(&realm->inodes_with_caps_lock);
587 list_for_each_entry(ci, &realm->inodes_with_caps,
588 i_snap_realm_item) {
589 struct inode *inode = igrab(&ci->vfs_inode);
590 if (!inode)
591 continue;
592 spin_unlock(&realm->inodes_with_caps_lock);
593 if (lastinode)
594 iput(lastinode);
595 lastinode = inode;
596 ceph_queue_cap_snap(ci);
597 spin_lock(&realm->inodes_with_caps_lock);
598 }
599 spin_unlock(&realm->inodes_with_caps_lock);
600 if (lastinode)
601 iput(lastinode);
602
603 list_for_each_entry(child, &realm->children, child_item) {
604 dout("queue_realm_cap_snaps %p %llx queue child %p %llx\n",
605 realm, realm->ino, child, child->ino);
606 list_del_init(&child->dirty_item);
607 list_add(&child->dirty_item, &realm->dirty_item);
608 }
609
610 list_del_init(&realm->dirty_item);
611 dout("queue_realm_cap_snaps %p %llx done\n", realm, realm->ino);
612}
613
614/*
615 * Parse and apply a snapblob "snap trace" from the MDS. This specifies
616 * the snap realm parameters from a given realm and all of its ancestors,
617 * up to the root.
618 *
619 * Caller must hold snap_rwsem for write.
620 */
621int ceph_update_snap_trace(struct ceph_mds_client *mdsc,
622 void *p, void *e, bool deletion)
623{
624 struct ceph_mds_snap_realm *ri; /* encoded */
625 __le64 *snaps; /* encoded */
626 __le64 *prior_parent_snaps; /* encoded */
627 struct ceph_snap_realm *realm;
628 int invalidate = 0;
629 int err = -ENOMEM;
630 LIST_HEAD(dirty_realms);
631
632 dout("update_snap_trace deletion=%d\n", deletion);
633more:
634 ceph_decode_need(&p, e, sizeof(*ri), bad);
635 ri = p;
636 p += sizeof(*ri);
637 ceph_decode_need(&p, e, sizeof(u64)*(le32_to_cpu(ri->num_snaps) +
638 le32_to_cpu(ri->num_prior_parent_snaps)), bad);
639 snaps = p;
640 p += sizeof(u64) * le32_to_cpu(ri->num_snaps);
641 prior_parent_snaps = p;
642 p += sizeof(u64) * le32_to_cpu(ri->num_prior_parent_snaps);
643
644 realm = ceph_lookup_snap_realm(mdsc, le64_to_cpu(ri->ino));
645 if (!realm) {
646 realm = ceph_create_snap_realm(mdsc, le64_to_cpu(ri->ino));
647 if (IS_ERR(realm)) {
648 err = PTR_ERR(realm);
649 goto fail;
650 }
651 }
652
653 /* ensure the parent is correct */
654 err = adjust_snap_realm_parent(mdsc, realm, le64_to_cpu(ri->parent));
655 if (err < 0)
656 goto fail;
657 invalidate += err;
658
659 if (le64_to_cpu(ri->seq) > realm->seq) {
660 dout("update_snap_trace updating %llx %p %lld -> %lld\n",
661 realm->ino, realm, realm->seq, le64_to_cpu(ri->seq));
662 /* update realm parameters, snap lists */
663 realm->seq = le64_to_cpu(ri->seq);
664 realm->created = le64_to_cpu(ri->created);
665 realm->parent_since = le64_to_cpu(ri->parent_since);
666
667 realm->num_snaps = le32_to_cpu(ri->num_snaps);
668 err = dup_array(&realm->snaps, snaps, realm->num_snaps);
669 if (err < 0)
670 goto fail;
671
672 realm->num_prior_parent_snaps =
673 le32_to_cpu(ri->num_prior_parent_snaps);
674 err = dup_array(&realm->prior_parent_snaps, prior_parent_snaps,
675 realm->num_prior_parent_snaps);
676 if (err < 0)
677 goto fail;
678
679 /* queue realm for cap_snap creation */
680 list_add(&realm->dirty_item, &dirty_realms);
681
682 invalidate = 1;
683 } else if (!realm->cached_context) {
684 dout("update_snap_trace %llx %p seq %lld new\n",
685 realm->ino, realm, realm->seq);
686 invalidate = 1;
687 } else {
688 dout("update_snap_trace %llx %p seq %lld unchanged\n",
689 realm->ino, realm, realm->seq);
690 }
691
692 dout("done with %llx %p, invalidated=%d, %p %p\n", realm->ino,
693 realm, invalidate, p, e);
694
695 if (p < e)
696 goto more;
697
698 /* invalidate when we reach the _end_ (root) of the trace */
699 if (invalidate)
700 rebuild_snap_realms(realm);
701
702 /*
703 * queue cap snaps _after_ we've built the new snap contexts,
704 * so that i_head_snapc can be set appropriately.
705 */
706 while (!list_empty(&dirty_realms)) {
707 realm = list_first_entry(&dirty_realms, struct ceph_snap_realm,
708 dirty_item);
709 queue_realm_cap_snaps(realm);
710 }
711
712 __cleanup_empty_realms(mdsc);
713 return 0;
714
715bad:
716 err = -EINVAL;
717fail:
718 pr_err("update_snap_trace error %d\n", err);
719 return err;
720}
721
722
723/*
724 * Send any cap_snaps that are queued for flush. Try to carry
725 * s_mutex across multiple snap flushes to avoid locking overhead.
726 *
727 * Caller holds no locks.
728 */
729static void flush_snaps(struct ceph_mds_client *mdsc)
730{
731 struct ceph_inode_info *ci;
732 struct inode *inode;
733 struct ceph_mds_session *session = NULL;
734
735 dout("flush_snaps\n");
736 spin_lock(&mdsc->snap_flush_lock);
737 while (!list_empty(&mdsc->snap_flush_list)) {
738 ci = list_first_entry(&mdsc->snap_flush_list,
739 struct ceph_inode_info, i_snap_flush_item);
740 inode = &ci->vfs_inode;
741 ihold(inode);
742 spin_unlock(&mdsc->snap_flush_lock);
743 spin_lock(&ci->i_ceph_lock);
744 __ceph_flush_snaps(ci, &session, 0);
745 spin_unlock(&ci->i_ceph_lock);
746 iput(inode);
747 spin_lock(&mdsc->snap_flush_lock);
748 }
749 spin_unlock(&mdsc->snap_flush_lock);
750
751 if (session) {
752 mutex_unlock(&session->s_mutex);
753 ceph_put_mds_session(session);
754 }
755 dout("flush_snaps done\n");
756}
757
758
759/*
760 * Handle a snap notification from the MDS.
761 *
762 * This can take two basic forms: the simplest is just a snap creation
763 * or deletion notification on an existing realm. This should update the
764 * realm and its children.
765 *
766 * The more difficult case is realm creation, due to snap creation at a
767 * new point in the file hierarchy, or due to a rename that moves a file or
768 * directory into another realm.
769 */
770void ceph_handle_snap(struct ceph_mds_client *mdsc,
771 struct ceph_mds_session *session,
772 struct ceph_msg *msg)
773{
774 struct super_block *sb = mdsc->fsc->sb;
775 int mds = session->s_mds;
776 u64 split;
777 int op;
778 int trace_len;
779 struct ceph_snap_realm *realm = NULL;
780 void *p = msg->front.iov_base;
781 void *e = p + msg->front.iov_len;
782 struct ceph_mds_snap_head *h;
783 int num_split_inos, num_split_realms;
784 __le64 *split_inos = NULL, *split_realms = NULL;
785 int i;
786 int locked_rwsem = 0;
787
788 /* decode */
789 if (msg->front.iov_len < sizeof(*h))
790 goto bad;
791 h = p;
792 op = le32_to_cpu(h->op);
793 split = le64_to_cpu(h->split); /* non-zero if we are splitting an
794 * existing realm */
795 num_split_inos = le32_to_cpu(h->num_split_inos);
796 num_split_realms = le32_to_cpu(h->num_split_realms);
797 trace_len = le32_to_cpu(h->trace_len);
798 p += sizeof(*h);
799
800 dout("handle_snap from mds%d op %s split %llx tracelen %d\n", mds,
801 ceph_snap_op_name(op), split, trace_len);
802
803 mutex_lock(&session->s_mutex);
804 session->s_seq++;
805 mutex_unlock(&session->s_mutex);
806
807 down_write(&mdsc->snap_rwsem);
808 locked_rwsem = 1;
809
810 if (op == CEPH_SNAP_OP_SPLIT) {
811 struct ceph_mds_snap_realm *ri;
812
813 /*
814 * A "split" breaks part of an existing realm off into
815 * a new realm. The MDS provides a list of inodes
816 * (with caps) and child realms that belong to the new
817 * child.
818 */
819 split_inos = p;
820 p += sizeof(u64) * num_split_inos;
821 split_realms = p;
822 p += sizeof(u64) * num_split_realms;
823 ceph_decode_need(&p, e, sizeof(*ri), bad);
824 /* we will peek at realm info here, but will _not_
825 * advance p, as the realm update will occur below in
826 * ceph_update_snap_trace. */
827 ri = p;
828
829 realm = ceph_lookup_snap_realm(mdsc, split);
830 if (!realm) {
831 realm = ceph_create_snap_realm(mdsc, split);
832 if (IS_ERR(realm))
833 goto out;
834 }
835 ceph_get_snap_realm(mdsc, realm);
836
837 dout("splitting snap_realm %llx %p\n", realm->ino, realm);
838 for (i = 0; i < num_split_inos; i++) {
839 struct ceph_vino vino = {
840 .ino = le64_to_cpu(split_inos[i]),
841 .snap = CEPH_NOSNAP,
842 };
843 struct inode *inode = ceph_find_inode(sb, vino);
844 struct ceph_inode_info *ci;
845 struct ceph_snap_realm *oldrealm;
846
847 if (!inode)
848 continue;
849 ci = ceph_inode(inode);
850
851 spin_lock(&ci->i_ceph_lock);
852 if (!ci->i_snap_realm)
853 goto skip_inode;
854 /*
855 * If this inode belongs to a realm that was
856 * created after our new realm, we experienced
857 * a race (due to another split notifications
858 * arriving from a different MDS). So skip
859 * this inode.
860 */
861 if (ci->i_snap_realm->created >
862 le64_to_cpu(ri->created)) {
863 dout(" leaving %p in newer realm %llx %p\n",
864 inode, ci->i_snap_realm->ino,
865 ci->i_snap_realm);
866 goto skip_inode;
867 }
868 dout(" will move %p to split realm %llx %p\n",
869 inode, realm->ino, realm);
870 /*
871 * Move the inode to the new realm
872 */
873 spin_lock(&realm->inodes_with_caps_lock);
874 list_del_init(&ci->i_snap_realm_item);
875 list_add(&ci->i_snap_realm_item,
876 &realm->inodes_with_caps);
877 oldrealm = ci->i_snap_realm;
878 ci->i_snap_realm = realm;
879 spin_unlock(&realm->inodes_with_caps_lock);
880 spin_unlock(&ci->i_ceph_lock);
881
882 ceph_get_snap_realm(mdsc, realm);
883 ceph_put_snap_realm(mdsc, oldrealm);
884
885 iput(inode);
886 continue;
887
888skip_inode:
889 spin_unlock(&ci->i_ceph_lock);
890 iput(inode);
891 }
892
893 /* we may have taken some of the old realm's children. */
894 for (i = 0; i < num_split_realms; i++) {
895 struct ceph_snap_realm *child =
896 ceph_lookup_snap_realm(mdsc,
897 le64_to_cpu(split_realms[i]));
898 if (!child)
899 continue;
900 adjust_snap_realm_parent(mdsc, child, realm->ino);
901 }
902 }
903
904 /*
905 * update using the provided snap trace. if we are deleting a
906 * snap, we can avoid queueing cap_snaps.
907 */
908 ceph_update_snap_trace(mdsc, p, e,
909 op == CEPH_SNAP_OP_DESTROY);
910
911 if (op == CEPH_SNAP_OP_SPLIT)
912 /* we took a reference when we created the realm, above */
913 ceph_put_snap_realm(mdsc, realm);
914
915 __cleanup_empty_realms(mdsc);
916
917 up_write(&mdsc->snap_rwsem);
918
919 flush_snaps(mdsc);
920 return;
921
922bad:
923 pr_err("corrupt snap message from mds%d\n", mds);
924 ceph_msg_dump(msg);
925out:
926 if (locked_rwsem)
927 up_write(&mdsc->snap_rwsem);
928 return;
929}
930
931
932
1// SPDX-License-Identifier: GPL-2.0
2#include <linux/ceph/ceph_debug.h>
3
4#include <linux/sort.h>
5#include <linux/slab.h>
6#include <linux/iversion.h>
7#include "super.h"
8#include "mds_client.h"
9#include <linux/ceph/decode.h>
10
11/* unused map expires after 5 minutes */
12#define CEPH_SNAPID_MAP_TIMEOUT (5 * 60 * HZ)
13
14/*
15 * Snapshots in ceph are driven in large part by cooperation from the
16 * client. In contrast to local file systems or file servers that
17 * implement snapshots at a single point in the system, ceph's
18 * distributed access to storage requires clients to help decide
19 * whether a write logically occurs before or after a recently created
20 * snapshot.
21 *
22 * This provides a perfect instantanous client-wide snapshot. Between
23 * clients, however, snapshots may appear to be applied at slightly
24 * different points in time, depending on delays in delivering the
25 * snapshot notification.
26 *
27 * Snapshots are _not_ file system-wide. Instead, each snapshot
28 * applies to the subdirectory nested beneath some directory. This
29 * effectively divides the hierarchy into multiple "realms," where all
30 * of the files contained by each realm share the same set of
31 * snapshots. An individual realm's snap set contains snapshots
32 * explicitly created on that realm, as well as any snaps in its
33 * parent's snap set _after_ the point at which the parent became it's
34 * parent (due to, say, a rename). Similarly, snaps from prior parents
35 * during the time intervals during which they were the parent are included.
36 *
37 * The client is spared most of this detail, fortunately... it must only
38 * maintains a hierarchy of realms reflecting the current parent/child
39 * realm relationship, and for each realm has an explicit list of snaps
40 * inherited from prior parents.
41 *
42 * A snap_realm struct is maintained for realms containing every inode
43 * with an open cap in the system. (The needed snap realm information is
44 * provided by the MDS whenever a cap is issued, i.e., on open.) A 'seq'
45 * version number is used to ensure that as realm parameters change (new
46 * snapshot, new parent, etc.) the client's realm hierarchy is updated.
47 *
48 * The realm hierarchy drives the generation of a 'snap context' for each
49 * realm, which simply lists the resulting set of snaps for the realm. This
50 * is attached to any writes sent to OSDs.
51 */
52/*
53 * Unfortunately error handling is a bit mixed here. If we get a snap
54 * update, but don't have enough memory to update our realm hierarchy,
55 * it's not clear what we can do about it (besides complaining to the
56 * console).
57 */
58
59
60/*
61 * increase ref count for the realm
62 *
63 * caller must hold snap_rwsem for write.
64 */
65void ceph_get_snap_realm(struct ceph_mds_client *mdsc,
66 struct ceph_snap_realm *realm)
67{
68 dout("get_realm %p %d -> %d\n", realm,
69 atomic_read(&realm->nref), atomic_read(&realm->nref)+1);
70 /*
71 * since we _only_ increment realm refs or empty the empty
72 * list with snap_rwsem held, adjusting the empty list here is
73 * safe. we do need to protect against concurrent empty list
74 * additions, however.
75 */
76 if (atomic_inc_return(&realm->nref) == 1) {
77 spin_lock(&mdsc->snap_empty_lock);
78 list_del_init(&realm->empty_item);
79 spin_unlock(&mdsc->snap_empty_lock);
80 }
81}
82
83static void __insert_snap_realm(struct rb_root *root,
84 struct ceph_snap_realm *new)
85{
86 struct rb_node **p = &root->rb_node;
87 struct rb_node *parent = NULL;
88 struct ceph_snap_realm *r = NULL;
89
90 while (*p) {
91 parent = *p;
92 r = rb_entry(parent, struct ceph_snap_realm, node);
93 if (new->ino < r->ino)
94 p = &(*p)->rb_left;
95 else if (new->ino > r->ino)
96 p = &(*p)->rb_right;
97 else
98 BUG();
99 }
100
101 rb_link_node(&new->node, parent, p);
102 rb_insert_color(&new->node, root);
103}
104
105/*
106 * create and get the realm rooted at @ino and bump its ref count.
107 *
108 * caller must hold snap_rwsem for write.
109 */
110static struct ceph_snap_realm *ceph_create_snap_realm(
111 struct ceph_mds_client *mdsc,
112 u64 ino)
113{
114 struct ceph_snap_realm *realm;
115
116 realm = kzalloc(sizeof(*realm), GFP_NOFS);
117 if (!realm)
118 return ERR_PTR(-ENOMEM);
119
120 atomic_set(&realm->nref, 1); /* for caller */
121 realm->ino = ino;
122 INIT_LIST_HEAD(&realm->children);
123 INIT_LIST_HEAD(&realm->child_item);
124 INIT_LIST_HEAD(&realm->empty_item);
125 INIT_LIST_HEAD(&realm->dirty_item);
126 INIT_LIST_HEAD(&realm->inodes_with_caps);
127 spin_lock_init(&realm->inodes_with_caps_lock);
128 __insert_snap_realm(&mdsc->snap_realms, realm);
129 mdsc->num_snap_realms++;
130
131 dout("create_snap_realm %llx %p\n", realm->ino, realm);
132 return realm;
133}
134
135/*
136 * lookup the realm rooted at @ino.
137 *
138 * caller must hold snap_rwsem for write.
139 */
140static struct ceph_snap_realm *__lookup_snap_realm(struct ceph_mds_client *mdsc,
141 u64 ino)
142{
143 struct rb_node *n = mdsc->snap_realms.rb_node;
144 struct ceph_snap_realm *r;
145
146 while (n) {
147 r = rb_entry(n, struct ceph_snap_realm, node);
148 if (ino < r->ino)
149 n = n->rb_left;
150 else if (ino > r->ino)
151 n = n->rb_right;
152 else {
153 dout("lookup_snap_realm %llx %p\n", r->ino, r);
154 return r;
155 }
156 }
157 return NULL;
158}
159
160struct ceph_snap_realm *ceph_lookup_snap_realm(struct ceph_mds_client *mdsc,
161 u64 ino)
162{
163 struct ceph_snap_realm *r;
164 r = __lookup_snap_realm(mdsc, ino);
165 if (r)
166 ceph_get_snap_realm(mdsc, r);
167 return r;
168}
169
170static void __put_snap_realm(struct ceph_mds_client *mdsc,
171 struct ceph_snap_realm *realm);
172
173/*
174 * called with snap_rwsem (write)
175 */
176static void __destroy_snap_realm(struct ceph_mds_client *mdsc,
177 struct ceph_snap_realm *realm)
178{
179 dout("__destroy_snap_realm %p %llx\n", realm, realm->ino);
180
181 rb_erase(&realm->node, &mdsc->snap_realms);
182 mdsc->num_snap_realms--;
183
184 if (realm->parent) {
185 list_del_init(&realm->child_item);
186 __put_snap_realm(mdsc, realm->parent);
187 }
188
189 kfree(realm->prior_parent_snaps);
190 kfree(realm->snaps);
191 ceph_put_snap_context(realm->cached_context);
192 kfree(realm);
193}
194
195/*
196 * caller holds snap_rwsem (write)
197 */
198static void __put_snap_realm(struct ceph_mds_client *mdsc,
199 struct ceph_snap_realm *realm)
200{
201 dout("__put_snap_realm %llx %p %d -> %d\n", realm->ino, realm,
202 atomic_read(&realm->nref), atomic_read(&realm->nref)-1);
203 if (atomic_dec_and_test(&realm->nref))
204 __destroy_snap_realm(mdsc, realm);
205}
206
207/*
208 * caller needn't hold any locks
209 */
210void ceph_put_snap_realm(struct ceph_mds_client *mdsc,
211 struct ceph_snap_realm *realm)
212{
213 dout("put_snap_realm %llx %p %d -> %d\n", realm->ino, realm,
214 atomic_read(&realm->nref), atomic_read(&realm->nref)-1);
215 if (!atomic_dec_and_test(&realm->nref))
216 return;
217
218 if (down_write_trylock(&mdsc->snap_rwsem)) {
219 __destroy_snap_realm(mdsc, realm);
220 up_write(&mdsc->snap_rwsem);
221 } else {
222 spin_lock(&mdsc->snap_empty_lock);
223 list_add(&realm->empty_item, &mdsc->snap_empty);
224 spin_unlock(&mdsc->snap_empty_lock);
225 }
226}
227
228/*
229 * Clean up any realms whose ref counts have dropped to zero. Note
230 * that this does not include realms who were created but not yet
231 * used.
232 *
233 * Called under snap_rwsem (write)
234 */
235static void __cleanup_empty_realms(struct ceph_mds_client *mdsc)
236{
237 struct ceph_snap_realm *realm;
238
239 spin_lock(&mdsc->snap_empty_lock);
240 while (!list_empty(&mdsc->snap_empty)) {
241 realm = list_first_entry(&mdsc->snap_empty,
242 struct ceph_snap_realm, empty_item);
243 list_del(&realm->empty_item);
244 spin_unlock(&mdsc->snap_empty_lock);
245 __destroy_snap_realm(mdsc, realm);
246 spin_lock(&mdsc->snap_empty_lock);
247 }
248 spin_unlock(&mdsc->snap_empty_lock);
249}
250
251void ceph_cleanup_empty_realms(struct ceph_mds_client *mdsc)
252{
253 down_write(&mdsc->snap_rwsem);
254 __cleanup_empty_realms(mdsc);
255 up_write(&mdsc->snap_rwsem);
256}
257
258/*
259 * adjust the parent realm of a given @realm. adjust child list, and parent
260 * pointers, and ref counts appropriately.
261 *
262 * return true if parent was changed, 0 if unchanged, <0 on error.
263 *
264 * caller must hold snap_rwsem for write.
265 */
266static int adjust_snap_realm_parent(struct ceph_mds_client *mdsc,
267 struct ceph_snap_realm *realm,
268 u64 parentino)
269{
270 struct ceph_snap_realm *parent;
271
272 if (realm->parent_ino == parentino)
273 return 0;
274
275 parent = ceph_lookup_snap_realm(mdsc, parentino);
276 if (!parent) {
277 parent = ceph_create_snap_realm(mdsc, parentino);
278 if (IS_ERR(parent))
279 return PTR_ERR(parent);
280 }
281 dout("adjust_snap_realm_parent %llx %p: %llx %p -> %llx %p\n",
282 realm->ino, realm, realm->parent_ino, realm->parent,
283 parentino, parent);
284 if (realm->parent) {
285 list_del_init(&realm->child_item);
286 ceph_put_snap_realm(mdsc, realm->parent);
287 }
288 realm->parent_ino = parentino;
289 realm->parent = parent;
290 list_add(&realm->child_item, &parent->children);
291 return 1;
292}
293
294
295static int cmpu64_rev(const void *a, const void *b)
296{
297 if (*(u64 *)a < *(u64 *)b)
298 return 1;
299 if (*(u64 *)a > *(u64 *)b)
300 return -1;
301 return 0;
302}
303
304
305/*
306 * build the snap context for a given realm.
307 */
308static int build_snap_context(struct ceph_snap_realm *realm,
309 struct list_head* dirty_realms)
310{
311 struct ceph_snap_realm *parent = realm->parent;
312 struct ceph_snap_context *snapc;
313 int err = 0;
314 u32 num = realm->num_prior_parent_snaps + realm->num_snaps;
315
316 /*
317 * build parent context, if it hasn't been built.
318 * conservatively estimate that all parent snaps might be
319 * included by us.
320 */
321 if (parent) {
322 if (!parent->cached_context) {
323 err = build_snap_context(parent, dirty_realms);
324 if (err)
325 goto fail;
326 }
327 num += parent->cached_context->num_snaps;
328 }
329
330 /* do i actually need to update? not if my context seq
331 matches realm seq, and my parents' does to. (this works
332 because we rebuild_snap_realms() works _downward_ in
333 hierarchy after each update.) */
334 if (realm->cached_context &&
335 realm->cached_context->seq == realm->seq &&
336 (!parent ||
337 realm->cached_context->seq >= parent->cached_context->seq)) {
338 dout("build_snap_context %llx %p: %p seq %lld (%u snaps)"
339 " (unchanged)\n",
340 realm->ino, realm, realm->cached_context,
341 realm->cached_context->seq,
342 (unsigned int)realm->cached_context->num_snaps);
343 return 0;
344 }
345
346 /* alloc new snap context */
347 err = -ENOMEM;
348 if (num > (SIZE_MAX - sizeof(*snapc)) / sizeof(u64))
349 goto fail;
350 snapc = ceph_create_snap_context(num, GFP_NOFS);
351 if (!snapc)
352 goto fail;
353
354 /* build (reverse sorted) snap vector */
355 num = 0;
356 snapc->seq = realm->seq;
357 if (parent) {
358 u32 i;
359
360 /* include any of parent's snaps occurring _after_ my
361 parent became my parent */
362 for (i = 0; i < parent->cached_context->num_snaps; i++)
363 if (parent->cached_context->snaps[i] >=
364 realm->parent_since)
365 snapc->snaps[num++] =
366 parent->cached_context->snaps[i];
367 if (parent->cached_context->seq > snapc->seq)
368 snapc->seq = parent->cached_context->seq;
369 }
370 memcpy(snapc->snaps + num, realm->snaps,
371 sizeof(u64)*realm->num_snaps);
372 num += realm->num_snaps;
373 memcpy(snapc->snaps + num, realm->prior_parent_snaps,
374 sizeof(u64)*realm->num_prior_parent_snaps);
375 num += realm->num_prior_parent_snaps;
376
377 sort(snapc->snaps, num, sizeof(u64), cmpu64_rev, NULL);
378 snapc->num_snaps = num;
379 dout("build_snap_context %llx %p: %p seq %lld (%u snaps)\n",
380 realm->ino, realm, snapc, snapc->seq,
381 (unsigned int) snapc->num_snaps);
382
383 ceph_put_snap_context(realm->cached_context);
384 realm->cached_context = snapc;
385 /* queue realm for cap_snap creation */
386 list_add_tail(&realm->dirty_item, dirty_realms);
387 return 0;
388
389fail:
390 /*
391 * if we fail, clear old (incorrect) cached_context... hopefully
392 * we'll have better luck building it later
393 */
394 if (realm->cached_context) {
395 ceph_put_snap_context(realm->cached_context);
396 realm->cached_context = NULL;
397 }
398 pr_err("build_snap_context %llx %p fail %d\n", realm->ino,
399 realm, err);
400 return err;
401}
402
403/*
404 * rebuild snap context for the given realm and all of its children.
405 */
406static void rebuild_snap_realms(struct ceph_snap_realm *realm,
407 struct list_head *dirty_realms)
408{
409 struct ceph_snap_realm *child;
410
411 dout("rebuild_snap_realms %llx %p\n", realm->ino, realm);
412 build_snap_context(realm, dirty_realms);
413
414 list_for_each_entry(child, &realm->children, child_item)
415 rebuild_snap_realms(child, dirty_realms);
416}
417
418
419/*
420 * helper to allocate and decode an array of snapids. free prior
421 * instance, if any.
422 */
423static int dup_array(u64 **dst, __le64 *src, u32 num)
424{
425 u32 i;
426
427 kfree(*dst);
428 if (num) {
429 *dst = kcalloc(num, sizeof(u64), GFP_NOFS);
430 if (!*dst)
431 return -ENOMEM;
432 for (i = 0; i < num; i++)
433 (*dst)[i] = get_unaligned_le64(src + i);
434 } else {
435 *dst = NULL;
436 }
437 return 0;
438}
439
440static bool has_new_snaps(struct ceph_snap_context *o,
441 struct ceph_snap_context *n)
442{
443 if (n->num_snaps == 0)
444 return false;
445 /* snaps are in descending order */
446 return n->snaps[0] > o->seq;
447}
448
449/*
450 * When a snapshot is applied, the size/mtime inode metadata is queued
451 * in a ceph_cap_snap (one for each snapshot) until writeback
452 * completes and the metadata can be flushed back to the MDS.
453 *
454 * However, if a (sync) write is currently in-progress when we apply
455 * the snapshot, we have to wait until the write succeeds or fails
456 * (and a final size/mtime is known). In this case the
457 * cap_snap->writing = 1, and is said to be "pending." When the write
458 * finishes, we __ceph_finish_cap_snap().
459 *
460 * Caller must hold snap_rwsem for read (i.e., the realm topology won't
461 * change).
462 */
463void ceph_queue_cap_snap(struct ceph_inode_info *ci)
464{
465 struct inode *inode = &ci->vfs_inode;
466 struct ceph_cap_snap *capsnap;
467 struct ceph_snap_context *old_snapc, *new_snapc;
468 struct ceph_buffer *old_blob = NULL;
469 int used, dirty;
470
471 capsnap = kzalloc(sizeof(*capsnap), GFP_NOFS);
472 if (!capsnap) {
473 pr_err("ENOMEM allocating ceph_cap_snap on %p\n", inode);
474 return;
475 }
476
477 spin_lock(&ci->i_ceph_lock);
478 used = __ceph_caps_used(ci);
479 dirty = __ceph_caps_dirty(ci);
480
481 old_snapc = ci->i_head_snapc;
482 new_snapc = ci->i_snap_realm->cached_context;
483
484 /*
485 * If there is a write in progress, treat that as a dirty Fw,
486 * even though it hasn't completed yet; by the time we finish
487 * up this capsnap it will be.
488 */
489 if (used & CEPH_CAP_FILE_WR)
490 dirty |= CEPH_CAP_FILE_WR;
491
492 if (__ceph_have_pending_cap_snap(ci)) {
493 /* there is no point in queuing multiple "pending" cap_snaps,
494 as no new writes are allowed to start when pending, so any
495 writes in progress now were started before the previous
496 cap_snap. lucky us. */
497 dout("queue_cap_snap %p already pending\n", inode);
498 goto update_snapc;
499 }
500 if (ci->i_wrbuffer_ref_head == 0 &&
501 !(dirty & (CEPH_CAP_ANY_EXCL|CEPH_CAP_FILE_WR))) {
502 dout("queue_cap_snap %p nothing dirty|writing\n", inode);
503 goto update_snapc;
504 }
505
506 BUG_ON(!old_snapc);
507
508 /*
509 * There is no need to send FLUSHSNAP message to MDS if there is
510 * no new snapshot. But when there is dirty pages or on-going
511 * writes, we still need to create cap_snap. cap_snap is needed
512 * by the write path and page writeback path.
513 *
514 * also see ceph_try_drop_cap_snap()
515 */
516 if (has_new_snaps(old_snapc, new_snapc)) {
517 if (dirty & (CEPH_CAP_ANY_EXCL|CEPH_CAP_FILE_WR))
518 capsnap->need_flush = true;
519 } else {
520 if (!(used & CEPH_CAP_FILE_WR) &&
521 ci->i_wrbuffer_ref_head == 0) {
522 dout("queue_cap_snap %p "
523 "no new_snap|dirty_page|writing\n", inode);
524 goto update_snapc;
525 }
526 }
527
528 dout("queue_cap_snap %p cap_snap %p queuing under %p %s %s\n",
529 inode, capsnap, old_snapc, ceph_cap_string(dirty),
530 capsnap->need_flush ? "" : "no_flush");
531 ihold(inode);
532
533 refcount_set(&capsnap->nref, 1);
534 INIT_LIST_HEAD(&capsnap->ci_item);
535
536 capsnap->follows = old_snapc->seq;
537 capsnap->issued = __ceph_caps_issued(ci, NULL);
538 capsnap->dirty = dirty;
539
540 capsnap->mode = inode->i_mode;
541 capsnap->uid = inode->i_uid;
542 capsnap->gid = inode->i_gid;
543
544 if (dirty & CEPH_CAP_XATTR_EXCL) {
545 old_blob = __ceph_build_xattrs_blob(ci);
546 capsnap->xattr_blob =
547 ceph_buffer_get(ci->i_xattrs.blob);
548 capsnap->xattr_version = ci->i_xattrs.version;
549 } else {
550 capsnap->xattr_blob = NULL;
551 capsnap->xattr_version = 0;
552 }
553
554 capsnap->inline_data = ci->i_inline_version != CEPH_INLINE_NONE;
555
556 /* dirty page count moved from _head to this cap_snap;
557 all subsequent writes page dirties occur _after_ this
558 snapshot. */
559 capsnap->dirty_pages = ci->i_wrbuffer_ref_head;
560 ci->i_wrbuffer_ref_head = 0;
561 capsnap->context = old_snapc;
562 list_add_tail(&capsnap->ci_item, &ci->i_cap_snaps);
563
564 if (used & CEPH_CAP_FILE_WR) {
565 dout("queue_cap_snap %p cap_snap %p snapc %p"
566 " seq %llu used WR, now pending\n", inode,
567 capsnap, old_snapc, old_snapc->seq);
568 capsnap->writing = 1;
569 } else {
570 /* note mtime, size NOW. */
571 __ceph_finish_cap_snap(ci, capsnap);
572 }
573 capsnap = NULL;
574 old_snapc = NULL;
575
576update_snapc:
577 if (ci->i_wrbuffer_ref_head == 0 &&
578 ci->i_wr_ref == 0 &&
579 ci->i_dirty_caps == 0 &&
580 ci->i_flushing_caps == 0) {
581 ci->i_head_snapc = NULL;
582 } else {
583 ci->i_head_snapc = ceph_get_snap_context(new_snapc);
584 dout(" new snapc is %p\n", new_snapc);
585 }
586 spin_unlock(&ci->i_ceph_lock);
587
588 ceph_buffer_put(old_blob);
589 kfree(capsnap);
590 ceph_put_snap_context(old_snapc);
591}
592
593/*
594 * Finalize the size, mtime for a cap_snap.. that is, settle on final values
595 * to be used for the snapshot, to be flushed back to the mds.
596 *
597 * If capsnap can now be flushed, add to snap_flush list, and return 1.
598 *
599 * Caller must hold i_ceph_lock.
600 */
601int __ceph_finish_cap_snap(struct ceph_inode_info *ci,
602 struct ceph_cap_snap *capsnap)
603{
604 struct inode *inode = &ci->vfs_inode;
605 struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
606
607 BUG_ON(capsnap->writing);
608 capsnap->size = inode->i_size;
609 capsnap->mtime = inode->i_mtime;
610 capsnap->atime = inode->i_atime;
611 capsnap->ctime = inode->i_ctime;
612 capsnap->btime = ci->i_btime;
613 capsnap->change_attr = inode_peek_iversion_raw(inode);
614 capsnap->time_warp_seq = ci->i_time_warp_seq;
615 capsnap->truncate_size = ci->i_truncate_size;
616 capsnap->truncate_seq = ci->i_truncate_seq;
617 if (capsnap->dirty_pages) {
618 dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu "
619 "still has %d dirty pages\n", inode, capsnap,
620 capsnap->context, capsnap->context->seq,
621 ceph_cap_string(capsnap->dirty), capsnap->size,
622 capsnap->dirty_pages);
623 return 0;
624 }
625
626 ci->i_ceph_flags |= CEPH_I_FLUSH_SNAPS;
627 dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu\n",
628 inode, capsnap, capsnap->context,
629 capsnap->context->seq, ceph_cap_string(capsnap->dirty),
630 capsnap->size);
631
632 spin_lock(&mdsc->snap_flush_lock);
633 if (list_empty(&ci->i_snap_flush_item))
634 list_add_tail(&ci->i_snap_flush_item, &mdsc->snap_flush_list);
635 spin_unlock(&mdsc->snap_flush_lock);
636 return 1; /* caller may want to ceph_flush_snaps */
637}
638
639/*
640 * Queue cap_snaps for snap writeback for this realm and its children.
641 * Called under snap_rwsem, so realm topology won't change.
642 */
643static void queue_realm_cap_snaps(struct ceph_snap_realm *realm)
644{
645 struct ceph_inode_info *ci;
646 struct inode *lastinode = NULL;
647
648 dout("queue_realm_cap_snaps %p %llx inodes\n", realm, realm->ino);
649
650 spin_lock(&realm->inodes_with_caps_lock);
651 list_for_each_entry(ci, &realm->inodes_with_caps, i_snap_realm_item) {
652 struct inode *inode = igrab(&ci->vfs_inode);
653 if (!inode)
654 continue;
655 spin_unlock(&realm->inodes_with_caps_lock);
656 /* avoid calling iput_final() while holding
657 * mdsc->snap_rwsem or in mds dispatch threads */
658 ceph_async_iput(lastinode);
659 lastinode = inode;
660 ceph_queue_cap_snap(ci);
661 spin_lock(&realm->inodes_with_caps_lock);
662 }
663 spin_unlock(&realm->inodes_with_caps_lock);
664 ceph_async_iput(lastinode);
665
666 dout("queue_realm_cap_snaps %p %llx done\n", realm, realm->ino);
667}
668
669/*
670 * Parse and apply a snapblob "snap trace" from the MDS. This specifies
671 * the snap realm parameters from a given realm and all of its ancestors,
672 * up to the root.
673 *
674 * Caller must hold snap_rwsem for write.
675 */
676int ceph_update_snap_trace(struct ceph_mds_client *mdsc,
677 void *p, void *e, bool deletion,
678 struct ceph_snap_realm **realm_ret)
679{
680 struct ceph_mds_snap_realm *ri; /* encoded */
681 __le64 *snaps; /* encoded */
682 __le64 *prior_parent_snaps; /* encoded */
683 struct ceph_snap_realm *realm = NULL;
684 struct ceph_snap_realm *first_realm = NULL;
685 int invalidate = 0;
686 int err = -ENOMEM;
687 LIST_HEAD(dirty_realms);
688
689 dout("update_snap_trace deletion=%d\n", deletion);
690more:
691 ceph_decode_need(&p, e, sizeof(*ri), bad);
692 ri = p;
693 p += sizeof(*ri);
694 ceph_decode_need(&p, e, sizeof(u64)*(le32_to_cpu(ri->num_snaps) +
695 le32_to_cpu(ri->num_prior_parent_snaps)), bad);
696 snaps = p;
697 p += sizeof(u64) * le32_to_cpu(ri->num_snaps);
698 prior_parent_snaps = p;
699 p += sizeof(u64) * le32_to_cpu(ri->num_prior_parent_snaps);
700
701 realm = ceph_lookup_snap_realm(mdsc, le64_to_cpu(ri->ino));
702 if (!realm) {
703 realm = ceph_create_snap_realm(mdsc, le64_to_cpu(ri->ino));
704 if (IS_ERR(realm)) {
705 err = PTR_ERR(realm);
706 goto fail;
707 }
708 }
709
710 /* ensure the parent is correct */
711 err = adjust_snap_realm_parent(mdsc, realm, le64_to_cpu(ri->parent));
712 if (err < 0)
713 goto fail;
714 invalidate += err;
715
716 if (le64_to_cpu(ri->seq) > realm->seq) {
717 dout("update_snap_trace updating %llx %p %lld -> %lld\n",
718 realm->ino, realm, realm->seq, le64_to_cpu(ri->seq));
719 /* update realm parameters, snap lists */
720 realm->seq = le64_to_cpu(ri->seq);
721 realm->created = le64_to_cpu(ri->created);
722 realm->parent_since = le64_to_cpu(ri->parent_since);
723
724 realm->num_snaps = le32_to_cpu(ri->num_snaps);
725 err = dup_array(&realm->snaps, snaps, realm->num_snaps);
726 if (err < 0)
727 goto fail;
728
729 realm->num_prior_parent_snaps =
730 le32_to_cpu(ri->num_prior_parent_snaps);
731 err = dup_array(&realm->prior_parent_snaps, prior_parent_snaps,
732 realm->num_prior_parent_snaps);
733 if (err < 0)
734 goto fail;
735
736 if (realm->seq > mdsc->last_snap_seq)
737 mdsc->last_snap_seq = realm->seq;
738
739 invalidate = 1;
740 } else if (!realm->cached_context) {
741 dout("update_snap_trace %llx %p seq %lld new\n",
742 realm->ino, realm, realm->seq);
743 invalidate = 1;
744 } else {
745 dout("update_snap_trace %llx %p seq %lld unchanged\n",
746 realm->ino, realm, realm->seq);
747 }
748
749 dout("done with %llx %p, invalidated=%d, %p %p\n", realm->ino,
750 realm, invalidate, p, e);
751
752 /* invalidate when we reach the _end_ (root) of the trace */
753 if (invalidate && p >= e)
754 rebuild_snap_realms(realm, &dirty_realms);
755
756 if (!first_realm)
757 first_realm = realm;
758 else
759 ceph_put_snap_realm(mdsc, realm);
760
761 if (p < e)
762 goto more;
763
764 /*
765 * queue cap snaps _after_ we've built the new snap contexts,
766 * so that i_head_snapc can be set appropriately.
767 */
768 while (!list_empty(&dirty_realms)) {
769 realm = list_first_entry(&dirty_realms, struct ceph_snap_realm,
770 dirty_item);
771 list_del_init(&realm->dirty_item);
772 queue_realm_cap_snaps(realm);
773 }
774
775 if (realm_ret)
776 *realm_ret = first_realm;
777 else
778 ceph_put_snap_realm(mdsc, first_realm);
779
780 __cleanup_empty_realms(mdsc);
781 return 0;
782
783bad:
784 err = -EINVAL;
785fail:
786 if (realm && !IS_ERR(realm))
787 ceph_put_snap_realm(mdsc, realm);
788 if (first_realm)
789 ceph_put_snap_realm(mdsc, first_realm);
790 pr_err("update_snap_trace error %d\n", err);
791 return err;
792}
793
794
795/*
796 * Send any cap_snaps that are queued for flush. Try to carry
797 * s_mutex across multiple snap flushes to avoid locking overhead.
798 *
799 * Caller holds no locks.
800 */
801static void flush_snaps(struct ceph_mds_client *mdsc)
802{
803 struct ceph_inode_info *ci;
804 struct inode *inode;
805 struct ceph_mds_session *session = NULL;
806
807 dout("flush_snaps\n");
808 spin_lock(&mdsc->snap_flush_lock);
809 while (!list_empty(&mdsc->snap_flush_list)) {
810 ci = list_first_entry(&mdsc->snap_flush_list,
811 struct ceph_inode_info, i_snap_flush_item);
812 inode = &ci->vfs_inode;
813 ihold(inode);
814 spin_unlock(&mdsc->snap_flush_lock);
815 ceph_flush_snaps(ci, &session);
816 /* avoid calling iput_final() while holding
817 * session->s_mutex or in mds dispatch threads */
818 ceph_async_iput(inode);
819 spin_lock(&mdsc->snap_flush_lock);
820 }
821 spin_unlock(&mdsc->snap_flush_lock);
822
823 if (session) {
824 mutex_unlock(&session->s_mutex);
825 ceph_put_mds_session(session);
826 }
827 dout("flush_snaps done\n");
828}
829
830
831/*
832 * Handle a snap notification from the MDS.
833 *
834 * This can take two basic forms: the simplest is just a snap creation
835 * or deletion notification on an existing realm. This should update the
836 * realm and its children.
837 *
838 * The more difficult case is realm creation, due to snap creation at a
839 * new point in the file hierarchy, or due to a rename that moves a file or
840 * directory into another realm.
841 */
842void ceph_handle_snap(struct ceph_mds_client *mdsc,
843 struct ceph_mds_session *session,
844 struct ceph_msg *msg)
845{
846 struct super_block *sb = mdsc->fsc->sb;
847 int mds = session->s_mds;
848 u64 split;
849 int op;
850 int trace_len;
851 struct ceph_snap_realm *realm = NULL;
852 void *p = msg->front.iov_base;
853 void *e = p + msg->front.iov_len;
854 struct ceph_mds_snap_head *h;
855 int num_split_inos, num_split_realms;
856 __le64 *split_inos = NULL, *split_realms = NULL;
857 int i;
858 int locked_rwsem = 0;
859
860 /* decode */
861 if (msg->front.iov_len < sizeof(*h))
862 goto bad;
863 h = p;
864 op = le32_to_cpu(h->op);
865 split = le64_to_cpu(h->split); /* non-zero if we are splitting an
866 * existing realm */
867 num_split_inos = le32_to_cpu(h->num_split_inos);
868 num_split_realms = le32_to_cpu(h->num_split_realms);
869 trace_len = le32_to_cpu(h->trace_len);
870 p += sizeof(*h);
871
872 dout("handle_snap from mds%d op %s split %llx tracelen %d\n", mds,
873 ceph_snap_op_name(op), split, trace_len);
874
875 mutex_lock(&session->s_mutex);
876 session->s_seq++;
877 mutex_unlock(&session->s_mutex);
878
879 down_write(&mdsc->snap_rwsem);
880 locked_rwsem = 1;
881
882 if (op == CEPH_SNAP_OP_SPLIT) {
883 struct ceph_mds_snap_realm *ri;
884
885 /*
886 * A "split" breaks part of an existing realm off into
887 * a new realm. The MDS provides a list of inodes
888 * (with caps) and child realms that belong to the new
889 * child.
890 */
891 split_inos = p;
892 p += sizeof(u64) * num_split_inos;
893 split_realms = p;
894 p += sizeof(u64) * num_split_realms;
895 ceph_decode_need(&p, e, sizeof(*ri), bad);
896 /* we will peek at realm info here, but will _not_
897 * advance p, as the realm update will occur below in
898 * ceph_update_snap_trace. */
899 ri = p;
900
901 realm = ceph_lookup_snap_realm(mdsc, split);
902 if (!realm) {
903 realm = ceph_create_snap_realm(mdsc, split);
904 if (IS_ERR(realm))
905 goto out;
906 }
907
908 dout("splitting snap_realm %llx %p\n", realm->ino, realm);
909 for (i = 0; i < num_split_inos; i++) {
910 struct ceph_vino vino = {
911 .ino = le64_to_cpu(split_inos[i]),
912 .snap = CEPH_NOSNAP,
913 };
914 struct inode *inode = ceph_find_inode(sb, vino);
915 struct ceph_inode_info *ci;
916 struct ceph_snap_realm *oldrealm;
917
918 if (!inode)
919 continue;
920 ci = ceph_inode(inode);
921
922 spin_lock(&ci->i_ceph_lock);
923 if (!ci->i_snap_realm)
924 goto skip_inode;
925 /*
926 * If this inode belongs to a realm that was
927 * created after our new realm, we experienced
928 * a race (due to another split notifications
929 * arriving from a different MDS). So skip
930 * this inode.
931 */
932 if (ci->i_snap_realm->created >
933 le64_to_cpu(ri->created)) {
934 dout(" leaving %p in newer realm %llx %p\n",
935 inode, ci->i_snap_realm->ino,
936 ci->i_snap_realm);
937 goto skip_inode;
938 }
939 dout(" will move %p to split realm %llx %p\n",
940 inode, realm->ino, realm);
941 /*
942 * Move the inode to the new realm
943 */
944 oldrealm = ci->i_snap_realm;
945 spin_lock(&oldrealm->inodes_with_caps_lock);
946 list_del_init(&ci->i_snap_realm_item);
947 spin_unlock(&oldrealm->inodes_with_caps_lock);
948
949 spin_lock(&realm->inodes_with_caps_lock);
950 list_add(&ci->i_snap_realm_item,
951 &realm->inodes_with_caps);
952 ci->i_snap_realm = realm;
953 if (realm->ino == ci->i_vino.ino)
954 realm->inode = inode;
955 spin_unlock(&realm->inodes_with_caps_lock);
956
957 spin_unlock(&ci->i_ceph_lock);
958
959 ceph_get_snap_realm(mdsc, realm);
960 ceph_put_snap_realm(mdsc, oldrealm);
961
962 /* avoid calling iput_final() while holding
963 * mdsc->snap_rwsem or mds in dispatch threads */
964 ceph_async_iput(inode);
965 continue;
966
967skip_inode:
968 spin_unlock(&ci->i_ceph_lock);
969 ceph_async_iput(inode);
970 }
971
972 /* we may have taken some of the old realm's children. */
973 for (i = 0; i < num_split_realms; i++) {
974 struct ceph_snap_realm *child =
975 __lookup_snap_realm(mdsc,
976 le64_to_cpu(split_realms[i]));
977 if (!child)
978 continue;
979 adjust_snap_realm_parent(mdsc, child, realm->ino);
980 }
981 }
982
983 /*
984 * update using the provided snap trace. if we are deleting a
985 * snap, we can avoid queueing cap_snaps.
986 */
987 ceph_update_snap_trace(mdsc, p, e,
988 op == CEPH_SNAP_OP_DESTROY, NULL);
989
990 if (op == CEPH_SNAP_OP_SPLIT)
991 /* we took a reference when we created the realm, above */
992 ceph_put_snap_realm(mdsc, realm);
993
994 __cleanup_empty_realms(mdsc);
995
996 up_write(&mdsc->snap_rwsem);
997
998 flush_snaps(mdsc);
999 return;
1000
1001bad:
1002 pr_err("corrupt snap message from mds%d\n", mds);
1003 ceph_msg_dump(msg);
1004out:
1005 if (locked_rwsem)
1006 up_write(&mdsc->snap_rwsem);
1007 return;
1008}
1009
1010struct ceph_snapid_map* ceph_get_snapid_map(struct ceph_mds_client *mdsc,
1011 u64 snap)
1012{
1013 struct ceph_snapid_map *sm, *exist;
1014 struct rb_node **p, *parent;
1015 int ret;
1016
1017 exist = NULL;
1018 spin_lock(&mdsc->snapid_map_lock);
1019 p = &mdsc->snapid_map_tree.rb_node;
1020 while (*p) {
1021 exist = rb_entry(*p, struct ceph_snapid_map, node);
1022 if (snap > exist->snap) {
1023 p = &(*p)->rb_left;
1024 } else if (snap < exist->snap) {
1025 p = &(*p)->rb_right;
1026 } else {
1027 if (atomic_inc_return(&exist->ref) == 1)
1028 list_del_init(&exist->lru);
1029 break;
1030 }
1031 exist = NULL;
1032 }
1033 spin_unlock(&mdsc->snapid_map_lock);
1034 if (exist) {
1035 dout("found snapid map %llx -> %x\n", exist->snap, exist->dev);
1036 return exist;
1037 }
1038
1039 sm = kmalloc(sizeof(*sm), GFP_NOFS);
1040 if (!sm)
1041 return NULL;
1042
1043 ret = get_anon_bdev(&sm->dev);
1044 if (ret < 0) {
1045 kfree(sm);
1046 return NULL;
1047 }
1048
1049 INIT_LIST_HEAD(&sm->lru);
1050 atomic_set(&sm->ref, 1);
1051 sm->snap = snap;
1052
1053 exist = NULL;
1054 parent = NULL;
1055 p = &mdsc->snapid_map_tree.rb_node;
1056 spin_lock(&mdsc->snapid_map_lock);
1057 while (*p) {
1058 parent = *p;
1059 exist = rb_entry(*p, struct ceph_snapid_map, node);
1060 if (snap > exist->snap)
1061 p = &(*p)->rb_left;
1062 else if (snap < exist->snap)
1063 p = &(*p)->rb_right;
1064 else
1065 break;
1066 exist = NULL;
1067 }
1068 if (exist) {
1069 if (atomic_inc_return(&exist->ref) == 1)
1070 list_del_init(&exist->lru);
1071 } else {
1072 rb_link_node(&sm->node, parent, p);
1073 rb_insert_color(&sm->node, &mdsc->snapid_map_tree);
1074 }
1075 spin_unlock(&mdsc->snapid_map_lock);
1076 if (exist) {
1077 free_anon_bdev(sm->dev);
1078 kfree(sm);
1079 dout("found snapid map %llx -> %x\n", exist->snap, exist->dev);
1080 return exist;
1081 }
1082
1083 dout("create snapid map %llx -> %x\n", sm->snap, sm->dev);
1084 return sm;
1085}
1086
1087void ceph_put_snapid_map(struct ceph_mds_client* mdsc,
1088 struct ceph_snapid_map *sm)
1089{
1090 if (!sm)
1091 return;
1092 if (atomic_dec_and_lock(&sm->ref, &mdsc->snapid_map_lock)) {
1093 if (!RB_EMPTY_NODE(&sm->node)) {
1094 sm->last_used = jiffies;
1095 list_add_tail(&sm->lru, &mdsc->snapid_map_lru);
1096 spin_unlock(&mdsc->snapid_map_lock);
1097 } else {
1098 /* already cleaned up by
1099 * ceph_cleanup_snapid_map() */
1100 spin_unlock(&mdsc->snapid_map_lock);
1101 kfree(sm);
1102 }
1103 }
1104}
1105
1106void ceph_trim_snapid_map(struct ceph_mds_client *mdsc)
1107{
1108 struct ceph_snapid_map *sm;
1109 unsigned long now;
1110 LIST_HEAD(to_free);
1111
1112 spin_lock(&mdsc->snapid_map_lock);
1113 now = jiffies;
1114
1115 while (!list_empty(&mdsc->snapid_map_lru)) {
1116 sm = list_first_entry(&mdsc->snapid_map_lru,
1117 struct ceph_snapid_map, lru);
1118 if (time_after(sm->last_used + CEPH_SNAPID_MAP_TIMEOUT, now))
1119 break;
1120
1121 rb_erase(&sm->node, &mdsc->snapid_map_tree);
1122 list_move(&sm->lru, &to_free);
1123 }
1124 spin_unlock(&mdsc->snapid_map_lock);
1125
1126 while (!list_empty(&to_free)) {
1127 sm = list_first_entry(&to_free, struct ceph_snapid_map, lru);
1128 list_del(&sm->lru);
1129 dout("trim snapid map %llx -> %x\n", sm->snap, sm->dev);
1130 free_anon_bdev(sm->dev);
1131 kfree(sm);
1132 }
1133}
1134
1135void ceph_cleanup_snapid_map(struct ceph_mds_client *mdsc)
1136{
1137 struct ceph_snapid_map *sm;
1138 struct rb_node *p;
1139 LIST_HEAD(to_free);
1140
1141 spin_lock(&mdsc->snapid_map_lock);
1142 while ((p = rb_first(&mdsc->snapid_map_tree))) {
1143 sm = rb_entry(p, struct ceph_snapid_map, node);
1144 rb_erase(p, &mdsc->snapid_map_tree);
1145 RB_CLEAR_NODE(p);
1146 list_move(&sm->lru, &to_free);
1147 }
1148 spin_unlock(&mdsc->snapid_map_lock);
1149
1150 while (!list_empty(&to_free)) {
1151 sm = list_first_entry(&to_free, struct ceph_snapid_map, lru);
1152 list_del(&sm->lru);
1153 free_anon_bdev(sm->dev);
1154 if (WARN_ON_ONCE(atomic_read(&sm->ref))) {
1155 pr_err("snapid map %llx -> %x still in use\n",
1156 sm->snap, sm->dev);
1157 }
1158 kfree(sm);
1159 }
1160}