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Yehuda Sadeh3d14c5d2010-04-06 15:14:15 -07001#include <linux/ceph/ceph_debug.h>
Sage Weil963b61e2009-10-06 11:31:12 -07002
Sage Weil963b61e2009-10-06 11:31:12 -07003#include <linux/sort.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +09004#include <linux/slab.h>
Sage Weil963b61e2009-10-06 11:31:12 -07005
6#include "super.h"
Yehuda Sadeh3d14c5d2010-04-06 15:14:15 -07007#include "mds_client.h"
8
9#include <linux/ceph/decode.h>
Sage Weil963b61e2009-10-06 11:31:12 -070010
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
Sage Weila105f002010-02-15 14:37:55 -080082static 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
Sage Weil963b61e2009-10-06 11:31:12 -0700104/*
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
Sage Weil963b61e2009-10-06 11:31:12 -0700119 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);
Sage Weilae00d4f2010-09-16 16:26:51 -0700124 INIT_LIST_HEAD(&realm->dirty_item);
Sage Weil963b61e2009-10-06 11:31:12 -0700125 INIT_LIST_HEAD(&realm->inodes_with_caps);
126 spin_lock_init(&realm->inodes_with_caps_lock);
Sage Weila105f002010-02-15 14:37:55 -0800127 __insert_snap_realm(&mdsc->snap_realms, realm);
Sage Weil963b61e2009-10-06 11:31:12 -0700128 dout("create_snap_realm %llx %p\n", realm->ino, realm);
129 return realm;
130}
131
132/*
Sage Weila105f002010-02-15 14:37:55 -0800133 * lookup the realm rooted at @ino.
Sage Weil963b61e2009-10-06 11:31:12 -0700134 *
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{
Sage Weila105f002010-02-15 14:37:55 -0800140 struct rb_node *n = mdsc->snap_realms.rb_node;
141 struct ceph_snap_realm *r;
Sage Weil963b61e2009-10-06 11:31:12 -0700142
Sage Weila105f002010-02-15 14:37:55 -0800143 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;
Sage Weil963b61e2009-10-06 11:31:12 -0700155}
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
Sage Weila105f002010-02-15 14:37:55 -0800168 rb_erase(&realm->node, &mdsc->snap_realms);
Sage Weil963b61e2009-10-06 11:31:12 -0700169
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);
Henry C Changa26a1852011-05-11 10:29:53 +0000209 list_add(&realm->empty_item, &mdsc->snap_empty);
Sage Weil963b61e2009-10-06 11:31:12 -0700210 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);
Sage Weil963b61e2009-10-06 11:31:12 -0700262 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;
Alex Elderaa711ee2012-07-13 20:35:11 -0500299 u32 num = realm->num_prior_parent_snaps + realm->num_snaps;
Sage Weil963b61e2009-10-06 11:31:12 -0700300
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 &&
Sage Weilec4318bc2010-03-19 13:24:39 -0700320 realm->cached_context->seq == realm->seq &&
Sage Weil963b61e2009-10-06 11:31:12 -0700321 (!parent ||
Sage Weilec4318bc2010-03-19 13:24:39 -0700322 realm->cached_context->seq >= parent->cached_context->seq)) {
Alex Elderaa711ee2012-07-13 20:35:11 -0500323 dout("build_snap_context %llx %p: %p seq %lld (%u snaps)"
Sage Weil963b61e2009-10-06 11:31:12 -0700324 " (unchanged)\n",
325 realm->ino, realm, realm->cached_context,
326 realm->cached_context->seq,
Alex Elderaa711ee2012-07-13 20:35:11 -0500327 (unsigned int) realm->cached_context->num_snaps);
Sage Weil963b61e2009-10-06 11:31:12 -0700328 return 0;
329 }
330
331 /* alloc new snap context */
332 err = -ENOMEM;
Xi Wanga3860c12012-05-31 16:26:04 -0700333 if (num > (SIZE_MAX - sizeof(*snapc)) / sizeof(u64))
Sage Weil963b61e2009-10-06 11:31:12 -0700334 goto fail;
Alex Elder812164f82013-04-30 00:44:32 -0500335 snapc = ceph_create_snap_context(num, GFP_NOFS);
Sage Weil963b61e2009-10-06 11:31:12 -0700336 if (!snapc)
337 goto fail;
Sage Weil963b61e2009-10-06 11:31:12 -0700338
339 /* build (reverse sorted) snap vector */
340 num = 0;
341 snapc->seq = realm->seq;
342 if (parent) {
Alex Elderaa711ee2012-07-13 20:35:11 -0500343 u32 i;
344
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300345 /* include any of parent's snaps occurring _after_ my
Sage Weil963b61e2009-10-06 11:31:12 -0700346 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;
Alex Elderaa711ee2012-07-13 20:35:11 -0500364 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);
Sage Weil963b61e2009-10-06 11:31:12 -0700367
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 */
Alex Elderaa711ee2012-07-13 20:35:11 -0500406static int dup_array(u64 **dst, __le64 *src, u32 num)
Sage Weil963b61e2009-10-06 11:31:12 -0700407{
Alex Elderaa711ee2012-07-13 20:35:11 -0500408 u32 i;
Sage Weil963b61e2009-10-06 11:31:12 -0700409
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 */
Sage Weilfc837c8f2010-04-13 11:41:22 -0700438void ceph_queue_cap_snap(struct ceph_inode_info *ci)
Sage Weil963b61e2009-10-06 11:31:12 -0700439{
440 struct inode *inode = &ci->vfs_inode;
441 struct ceph_cap_snap *capsnap;
Sage Weil4a625be2010-08-22 15:03:56 -0700442 int used, dirty;
Sage Weil963b61e2009-10-06 11:31:12 -0700443
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
Sage Weilbe655592011-11-30 09:47:09 -0800450 spin_lock(&ci->i_ceph_lock);
Sage Weil963b61e2009-10-06 11:31:12 -0700451 used = __ceph_caps_used(ci);
Sage Weil4a625be2010-08-22 15:03:56 -0700452 dirty = __ceph_caps_dirty(ci);
Sage Weilaf0ed562011-07-26 11:26:31 -0700453
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
Sage Weil963b61e2009-10-06 11:31:12 -0700462 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. */
Sage Weilfc837c8f2010-04-13 11:41:22 -0700467 dout("queue_cap_snap %p already pending\n", inode);
Sage Weil963b61e2009-10-06 11:31:12 -0700468 kfree(capsnap);
Sage Weile77dc3e2011-07-26 11:26:41 -0700469 } else if (dirty & (CEPH_CAP_AUTH_EXCL|CEPH_CAP_XATTR_EXCL|
470 CEPH_CAP_FILE_EXCL|CEPH_CAP_FILE_WR)) {
Sage Weilfc837c8f2010-04-13 11:41:22 -0700471 struct ceph_snap_context *snapc = ci->i_head_snapc;
472
Sage Weilaf0ed562011-07-26 11:26:31 -0700473 /*
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));
Dave Chinner0444d762011-03-29 18:08:50 +1100482 ihold(inode);
483
Sage Weil963b61e2009-10-06 11:31:12 -0700484 atomic_set(&capsnap->nref, 1);
485 capsnap->ci = ci;
486 INIT_LIST_HEAD(&capsnap->ci_item);
487 INIT_LIST_HEAD(&capsnap->flushing_item);
488
Sage Weil8bef9232010-09-14 15:45:44 -0700489 capsnap->follows = snapc->seq;
Sage Weil963b61e2009-10-06 11:31:12 -0700490 capsnap->issued = __ceph_caps_issued(ci, NULL);
Sage Weil4a625be2010-08-22 15:03:56 -0700491 capsnap->dirty = dirty;
Sage Weil963b61e2009-10-06 11:31:12 -0700492
493 capsnap->mode = inode->i_mode;
494 capsnap->uid = inode->i_uid;
495 capsnap->gid = inode->i_gid;
496
Sage Weil4a625be2010-08-22 15:03:56 -0700497 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 }
Sage Weil963b61e2009-10-06 11:31:12 -0700506
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;
Sage Weilfc837c8f2010-04-13 11:41:22 -0700512 capsnap->context = snapc;
Sage Weil7d8cb262010-08-24 08:44:16 -0700513 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);
Sage Weil963b61e2009-10-06 11:31:12 -0700516 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
Sage Weilbe655592011-11-30 09:47:09 -0800532 spin_unlock(&ci->i_ceph_lock);
Sage Weil963b61e2009-10-06 11:31:12 -0700533}
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 *
Sage Weilbe655592011-11-30 09:47:09 -0800541 * Caller must hold i_ceph_lock.
Sage Weil963b61e2009-10-06 11:31:12 -0700542 */
543int __ceph_finish_cap_snap(struct ceph_inode_info *ci,
544 struct ceph_cap_snap *capsnap)
545{
546 struct inode *inode = &ci->vfs_inode;
Yehuda Sadeh3d14c5d2010-04-06 15:14:15 -0700547 struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
Sage Weil963b61e2009-10-06 11:31:12 -0700548
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) {
Sage Weil819ccbf2010-04-01 09:33:46 -0700556 dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu "
Sage Weil963b61e2009-10-06 11:31:12 -0700557 "still has %d dirty pages\n", inode, capsnap,
558 capsnap->context, capsnap->context->seq,
Sage Weil819ccbf2010-04-01 09:33:46 -0700559 ceph_cap_string(capsnap->dirty), capsnap->size,
560 capsnap->dirty_pages);
Sage Weil963b61e2009-10-06 11:31:12 -0700561 return 0;
562 }
Sage Weil819ccbf2010-04-01 09:33:46 -0700563 dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu\n",
Sage Weil963b61e2009-10-06 11:31:12 -0700564 inode, capsnap, capsnap->context,
Sage Weil819ccbf2010-04-01 09:33:46 -0700565 capsnap->context->seq, ceph_cap_string(capsnap->dirty),
566 capsnap->size);
Sage Weil963b61e2009-10-06 11:31:12 -0700567
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
Sage Weiled326042010-08-16 13:37:31 -0700574/*
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
Sage Weile8e1ba962011-02-04 20:45:58 -0800603 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 }
Sage Weiled326042010-08-16 13:37:31 -0700609
Sage Weile8e1ba962011-02-04 20:45:58 -0800610 list_del_init(&realm->dirty_item);
Sage Weiled326042010-08-16 13:37:31 -0700611 dout("queue_realm_cap_snaps %p %llx done\n", realm, realm->ino);
612}
Sage Weil963b61e2009-10-06 11:31:12 -0700613
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;
Sage Weilae00d4f2010-09-16 16:26:51 -0700630 LIST_HEAD(dirty_realms);
Sage Weil963b61e2009-10-06 11:31:12 -0700631
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));
Sage Weil963b61e2009-10-06 11:31:12 -0700645 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
Sage Weil963b61e2009-10-06 11:31:12 -0700653 /* 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) {
Sage Weilae00d4f2010-09-16 16:26:51 -0700660 dout("update_snap_trace updating %llx %p %lld -> %lld\n",
661 realm->ino, realm, realm->seq, le64_to_cpu(ri->seq));
Sage Weil963b61e2009-10-06 11:31:12 -0700662 /* 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
Sage Weilae00d4f2010-09-16 16:26:51 -0700679 /* queue realm for cap_snap creation */
680 list_add(&realm->dirty_item, &dirty_realms);
681
Sage Weil963b61e2009-10-06 11:31:12 -0700682 invalidate = 1;
683 } else if (!realm->cached_context) {
Sage Weilae00d4f2010-09-16 16:26:51 -0700684 dout("update_snap_trace %llx %p seq %lld new\n",
685 realm->ino, realm, realm->seq);
Sage Weil963b61e2009-10-06 11:31:12 -0700686 invalidate = 1;
Sage Weilae00d4f2010-09-16 16:26:51 -0700687 } else {
688 dout("update_snap_trace %llx %p seq %lld unchanged\n",
689 realm->ino, realm, realm->seq);
Sage Weil963b61e2009-10-06 11:31:12 -0700690 }
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
Sage Weilae00d4f2010-09-16 16:26:51 -0700702 /*
703 * queue cap snaps _after_ we've built the new snap contexts,
704 * so that i_head_snapc can be set appropriately.
705 */
Sage Weile8e1ba962011-02-04 20:45:58 -0800706 while (!list_empty(&dirty_realms)) {
707 realm = list_first_entry(&dirty_realms, struct ceph_snap_realm,
708 dirty_item);
Sage Weilae00d4f2010-09-16 16:26:51 -0700709 queue_realm_cap_snaps(realm);
710 }
711
Sage Weil963b61e2009-10-06 11:31:12 -0700712 __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;
Sage Weil70b666c2011-05-27 09:24:26 -0700741 ihold(inode);
Sage Weil963b61e2009-10-06 11:31:12 -0700742 spin_unlock(&mdsc->snap_flush_lock);
Sage Weilbe655592011-11-30 09:47:09 -0800743 spin_lock(&ci->i_ceph_lock);
Sage Weile8351242010-09-17 08:03:08 -0700744 __ceph_flush_snaps(ci, &session, 0);
Sage Weilbe655592011-11-30 09:47:09 -0800745 spin_unlock(&ci->i_ceph_lock);
Sage Weil963b61e2009-10-06 11:31:12 -0700746 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,
Sage Weil2600d2d2010-02-22 15:12:16 -0800771 struct ceph_mds_session *session,
Sage Weil963b61e2009-10-06 11:31:12 -0700772 struct ceph_msg *msg)
773{
Yehuda Sadeh3d14c5d2010-04-06 15:14:15 -0700774 struct super_block *sb = mdsc->fsc->sb;
Sage Weil2600d2d2010-02-22 15:12:16 -0800775 int mds = session->s_mds;
Sage Weil963b61e2009-10-06 11:31:12 -0700776 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
Sage Weil963b61e2009-10-06 11:31:12 -0700788 /* 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
Sage Weil963b61e2009-10-06 11:31:12 -0700803 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);
Sage Weil963b61e2009-10-06 11:31:12 -0700830 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;
Sage Weilae00d4f2010-09-16 16:26:51 -0700845 struct ceph_snap_realm *oldrealm;
Sage Weil963b61e2009-10-06 11:31:12 -0700846
847 if (!inode)
848 continue;
849 ci = ceph_inode(inode);
850
Sage Weilbe655592011-11-30 09:47:09 -0800851 spin_lock(&ci->i_ceph_lock);
Sage Weil963b61e2009-10-06 11:31:12 -0700852 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 /*
Sage Weilae00d4f2010-09-16 16:26:51 -0700871 * Move the inode to the new realm
Sage Weil963b61e2009-10-06 11:31:12 -0700872 */
Sage Weil052bb342010-03-09 12:52:26 -0800873 spin_lock(&realm->inodes_with_caps_lock);
Sage Weil963b61e2009-10-06 11:31:12 -0700874 list_del_init(&ci->i_snap_realm_item);
Sage Weilae00d4f2010-09-16 16:26:51 -0700875 list_add(&ci->i_snap_realm_item,
876 &realm->inodes_with_caps);
877 oldrealm = ci->i_snap_realm;
878 ci->i_snap_realm = realm;
Sage Weil052bb342010-03-09 12:52:26 -0800879 spin_unlock(&realm->inodes_with_caps_lock);
Sage Weilbe655592011-11-30 09:47:09 -0800880 spin_unlock(&ci->i_ceph_lock);
Sage Weil963b61e2009-10-06 11:31:12 -0700881
Sage Weilae00d4f2010-09-16 16:26:51 -0700882 ceph_get_snap_realm(mdsc, realm);
883 ceph_put_snap_realm(mdsc, oldrealm);
Sage Weil963b61e2009-10-06 11:31:12 -0700884
885 iput(inode);
886 continue;
887
888skip_inode:
Sage Weilbe655592011-11-30 09:47:09 -0800889 spin_unlock(&ci->i_ceph_lock);
Sage Weil963b61e2009-10-06 11:31:12 -0700890 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]));
Sage Weil963b61e2009-10-06 11:31:12 -0700898 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
Sage Weilae00d4f2010-09-16 16:26:51 -0700911 if (op == CEPH_SNAP_OP_SPLIT)
Sage Weil963b61e2009-10-06 11:31:12 -0700912 /* we took a reference when we created the realm, above */
913 ceph_put_snap_realm(mdsc, realm);
Sage Weil963b61e2009-10-06 11:31:12 -0700914
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);
Sage Weil9ec7cab2009-12-14 15:13:47 -0800924 ceph_msg_dump(msg);
Sage Weil963b61e2009-10-06 11:31:12 -0700925out:
926 if (locked_rwsem)
927 up_write(&mdsc->snap_rwsem);
928 return;
929}
930
931
932