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Commit | Line | Data |
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3d14c5d2 | 1 | #include <linux/ceph/ceph_debug.h> |
963b61eb | 2 | |
963b61eb | 3 | #include <linux/sort.h> |
5a0e3ad6 | 4 | #include <linux/slab.h> |
963b61eb SW |
5 | |
6 | #include "super.h" | |
3d14c5d2 YS |
7 | #include "mds_client.h" |
8 | ||
9 | #include <linux/ceph/decode.h> | |
963b61eb SW |
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 | */ | |
62 | void 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 | ||
a105f00c SW |
82 | static 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 | ||
963b61eb SW |
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 | */ | |
109 | static 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 | ||
963b61eb SW |
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); | |
ae00d4f3 | 124 | INIT_LIST_HEAD(&realm->dirty_item); |
963b61eb SW |
125 | INIT_LIST_HEAD(&realm->inodes_with_caps); |
126 | spin_lock_init(&realm->inodes_with_caps_lock); | |
a105f00c | 127 | __insert_snap_realm(&mdsc->snap_realms, realm); |
963b61eb SW |
128 | dout("create_snap_realm %llx %p\n", realm->ino, realm); |
129 | return realm; | |
130 | } | |
131 | ||
132 | /* | |
a105f00c | 133 | * lookup the realm rooted at @ino. |
963b61eb SW |
134 | * |
135 | * caller must hold snap_rwsem for write. | |
136 | */ | |
137 | struct ceph_snap_realm *ceph_lookup_snap_realm(struct ceph_mds_client *mdsc, | |
138 | u64 ino) | |
139 | { | |
a105f00c SW |
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; | |
963b61eb SW |
155 | } |
156 | ||
157 | static void __put_snap_realm(struct ceph_mds_client *mdsc, | |
158 | struct ceph_snap_realm *realm); | |
159 | ||
160 | /* | |
161 | * called with snap_rwsem (write) | |
162 | */ | |
163 | static 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 | ||
a105f00c | 168 | rb_erase(&realm->node, &mdsc->snap_realms); |
963b61eb SW |
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 | */ | |
184 | static 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 | */ | |
196 | void 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); | |
a26a185d | 209 | list_add(&realm->empty_item, &mdsc->snap_empty); |
963b61eb SW |
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 | */ | |
221 | static 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 | ||
237 | void 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 | */ | |
252 | static 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); | |
963b61eb SW |
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 | ||
282 | static 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 | */ | |
294 | static 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 | int i; | |
300 | int num = realm->num_prior_parent_snaps + realm->num_snaps; | |
301 | ||
302 | /* | |
303 | * build parent context, if it hasn't been built. | |
304 | * conservatively estimate that all parent snaps might be | |
305 | * included by us. | |
306 | */ | |
307 | if (parent) { | |
308 | if (!parent->cached_context) { | |
309 | err = build_snap_context(parent); | |
310 | if (err) | |
311 | goto fail; | |
312 | } | |
313 | num += parent->cached_context->num_snaps; | |
314 | } | |
315 | ||
316 | /* do i actually need to update? not if my context seq | |
317 | matches realm seq, and my parents' does to. (this works | |
318 | because we rebuild_snap_realms() works _downward_ in | |
319 | hierarchy after each update.) */ | |
320 | if (realm->cached_context && | |
ec4318bc | 321 | realm->cached_context->seq == realm->seq && |
963b61eb | 322 | (!parent || |
ec4318bc | 323 | realm->cached_context->seq >= parent->cached_context->seq)) { |
963b61eb SW |
324 | dout("build_snap_context %llx %p: %p seq %lld (%d snaps)" |
325 | " (unchanged)\n", | |
326 | realm->ino, realm, realm->cached_context, | |
327 | realm->cached_context->seq, | |
328 | realm->cached_context->num_snaps); | |
329 | return 0; | |
330 | } | |
331 | ||
332 | /* alloc new snap context */ | |
333 | err = -ENOMEM; | |
a3860c1c | 334 | if (num > (SIZE_MAX - sizeof(*snapc)) / sizeof(u64)) |
963b61eb SW |
335 | goto fail; |
336 | snapc = kzalloc(sizeof(*snapc) + num*sizeof(u64), GFP_NOFS); | |
337 | if (!snapc) | |
338 | goto fail; | |
339 | atomic_set(&snapc->nref, 1); | |
340 | ||
341 | /* build (reverse sorted) snap vector */ | |
342 | num = 0; | |
343 | snapc->seq = realm->seq; | |
344 | if (parent) { | |
25985edc | 345 | /* include any of parent's snaps occurring _after_ my |
963b61eb SW |
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 (%d snaps)\n", | |
365 | realm->ino, realm, snapc, snapc->seq, snapc->num_snaps); | |
366 | ||
367 | if (realm->cached_context) | |
368 | ceph_put_snap_context(realm->cached_context); | |
369 | realm->cached_context = snapc; | |
370 | return 0; | |
371 | ||
372 | fail: | |
373 | /* | |
374 | * if we fail, clear old (incorrect) cached_context... hopefully | |
375 | * we'll have better luck building it later | |
376 | */ | |
377 | if (realm->cached_context) { | |
378 | ceph_put_snap_context(realm->cached_context); | |
379 | realm->cached_context = NULL; | |
380 | } | |
381 | pr_err("build_snap_context %llx %p fail %d\n", realm->ino, | |
382 | realm, err); | |
383 | return err; | |
384 | } | |
385 | ||
386 | /* | |
387 | * rebuild snap context for the given realm and all of its children. | |
388 | */ | |
389 | static void rebuild_snap_realms(struct ceph_snap_realm *realm) | |
390 | { | |
391 | struct ceph_snap_realm *child; | |
392 | ||
393 | dout("rebuild_snap_realms %llx %p\n", realm->ino, realm); | |
394 | build_snap_context(realm); | |
395 | ||
396 | list_for_each_entry(child, &realm->children, child_item) | |
397 | rebuild_snap_realms(child); | |
398 | } | |
399 | ||
400 | ||
401 | /* | |
402 | * helper to allocate and decode an array of snapids. free prior | |
403 | * instance, if any. | |
404 | */ | |
405 | static int dup_array(u64 **dst, __le64 *src, int num) | |
406 | { | |
407 | int i; | |
408 | ||
409 | kfree(*dst); | |
410 | if (num) { | |
411 | *dst = kcalloc(num, sizeof(u64), GFP_NOFS); | |
412 | if (!*dst) | |
413 | return -ENOMEM; | |
414 | for (i = 0; i < num; i++) | |
415 | (*dst)[i] = get_unaligned_le64(src + i); | |
416 | } else { | |
417 | *dst = NULL; | |
418 | } | |
419 | return 0; | |
420 | } | |
421 | ||
422 | ||
423 | /* | |
424 | * When a snapshot is applied, the size/mtime inode metadata is queued | |
425 | * in a ceph_cap_snap (one for each snapshot) until writeback | |
426 | * completes and the metadata can be flushed back to the MDS. | |
427 | * | |
428 | * However, if a (sync) write is currently in-progress when we apply | |
429 | * the snapshot, we have to wait until the write succeeds or fails | |
430 | * (and a final size/mtime is known). In this case the | |
431 | * cap_snap->writing = 1, and is said to be "pending." When the write | |
432 | * finishes, we __ceph_finish_cap_snap(). | |
433 | * | |
434 | * Caller must hold snap_rwsem for read (i.e., the realm topology won't | |
435 | * change). | |
436 | */ | |
fc837c8f | 437 | void ceph_queue_cap_snap(struct ceph_inode_info *ci) |
963b61eb SW |
438 | { |
439 | struct inode *inode = &ci->vfs_inode; | |
440 | struct ceph_cap_snap *capsnap; | |
4a625be4 | 441 | int used, dirty; |
963b61eb SW |
442 | |
443 | capsnap = kzalloc(sizeof(*capsnap), GFP_NOFS); | |
444 | if (!capsnap) { | |
445 | pr_err("ENOMEM allocating ceph_cap_snap on %p\n", inode); | |
446 | return; | |
447 | } | |
448 | ||
be655596 | 449 | spin_lock(&ci->i_ceph_lock); |
963b61eb | 450 | used = __ceph_caps_used(ci); |
4a625be4 | 451 | dirty = __ceph_caps_dirty(ci); |
af0ed569 SW |
452 | |
453 | /* | |
454 | * If there is a write in progress, treat that as a dirty Fw, | |
455 | * even though it hasn't completed yet; by the time we finish | |
456 | * up this capsnap it will be. | |
457 | */ | |
458 | if (used & CEPH_CAP_FILE_WR) | |
459 | dirty |= CEPH_CAP_FILE_WR; | |
460 | ||
963b61eb SW |
461 | if (__ceph_have_pending_cap_snap(ci)) { |
462 | /* there is no point in queuing multiple "pending" cap_snaps, | |
463 | as no new writes are allowed to start when pending, so any | |
464 | writes in progress now were started before the previous | |
465 | cap_snap. lucky us. */ | |
fc837c8f | 466 | dout("queue_cap_snap %p already pending\n", inode); |
963b61eb | 467 | kfree(capsnap); |
e77dc3e9 SW |
468 | } else if (dirty & (CEPH_CAP_AUTH_EXCL|CEPH_CAP_XATTR_EXCL| |
469 | CEPH_CAP_FILE_EXCL|CEPH_CAP_FILE_WR)) { | |
fc837c8f SW |
470 | struct ceph_snap_context *snapc = ci->i_head_snapc; |
471 | ||
af0ed569 SW |
472 | /* |
473 | * if we are a sync write, we may need to go to the snaprealm | |
474 | * to get the current snapc. | |
475 | */ | |
476 | if (!snapc) | |
477 | snapc = ci->i_snap_realm->cached_context; | |
478 | ||
479 | dout("queue_cap_snap %p cap_snap %p queuing under %p %s\n", | |
480 | inode, capsnap, snapc, ceph_cap_string(dirty)); | |
0444d76a DC |
481 | ihold(inode); |
482 | ||
963b61eb SW |
483 | atomic_set(&capsnap->nref, 1); |
484 | capsnap->ci = ci; | |
485 | INIT_LIST_HEAD(&capsnap->ci_item); | |
486 | INIT_LIST_HEAD(&capsnap->flushing_item); | |
487 | ||
8bef9239 | 488 | capsnap->follows = snapc->seq; |
963b61eb | 489 | capsnap->issued = __ceph_caps_issued(ci, NULL); |
4a625be4 | 490 | capsnap->dirty = dirty; |
963b61eb SW |
491 | |
492 | capsnap->mode = inode->i_mode; | |
493 | capsnap->uid = inode->i_uid; | |
494 | capsnap->gid = inode->i_gid; | |
495 | ||
4a625be4 SW |
496 | if (dirty & CEPH_CAP_XATTR_EXCL) { |
497 | __ceph_build_xattrs_blob(ci); | |
498 | capsnap->xattr_blob = | |
499 | ceph_buffer_get(ci->i_xattrs.blob); | |
500 | capsnap->xattr_version = ci->i_xattrs.version; | |
501 | } else { | |
502 | capsnap->xattr_blob = NULL; | |
503 | capsnap->xattr_version = 0; | |
504 | } | |
963b61eb SW |
505 | |
506 | /* dirty page count moved from _head to this cap_snap; | |
507 | all subsequent writes page dirties occur _after_ this | |
508 | snapshot. */ | |
509 | capsnap->dirty_pages = ci->i_wrbuffer_ref_head; | |
510 | ci->i_wrbuffer_ref_head = 0; | |
fc837c8f | 511 | capsnap->context = snapc; |
7d8cb26d SW |
512 | ci->i_head_snapc = |
513 | ceph_get_snap_context(ci->i_snap_realm->cached_context); | |
514 | dout(" new snapc is %p\n", ci->i_head_snapc); | |
963b61eb SW |
515 | list_add_tail(&capsnap->ci_item, &ci->i_cap_snaps); |
516 | ||
517 | if (used & CEPH_CAP_FILE_WR) { | |
518 | dout("queue_cap_snap %p cap_snap %p snapc %p" | |
519 | " seq %llu used WR, now pending\n", inode, | |
520 | capsnap, snapc, snapc->seq); | |
521 | capsnap->writing = 1; | |
522 | } else { | |
523 | /* note mtime, size NOW. */ | |
524 | __ceph_finish_cap_snap(ci, capsnap); | |
525 | } | |
526 | } else { | |
527 | dout("queue_cap_snap %p nothing dirty|writing\n", inode); | |
528 | kfree(capsnap); | |
529 | } | |
530 | ||
be655596 | 531 | spin_unlock(&ci->i_ceph_lock); |
963b61eb SW |
532 | } |
533 | ||
534 | /* | |
535 | * Finalize the size, mtime for a cap_snap.. that is, settle on final values | |
536 | * to be used for the snapshot, to be flushed back to the mds. | |
537 | * | |
538 | * If capsnap can now be flushed, add to snap_flush list, and return 1. | |
539 | * | |
be655596 | 540 | * Caller must hold i_ceph_lock. |
963b61eb SW |
541 | */ |
542 | int __ceph_finish_cap_snap(struct ceph_inode_info *ci, | |
543 | struct ceph_cap_snap *capsnap) | |
544 | { | |
545 | struct inode *inode = &ci->vfs_inode; | |
3d14c5d2 | 546 | struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc; |
963b61eb SW |
547 | |
548 | BUG_ON(capsnap->writing); | |
549 | capsnap->size = inode->i_size; | |
550 | capsnap->mtime = inode->i_mtime; | |
551 | capsnap->atime = inode->i_atime; | |
552 | capsnap->ctime = inode->i_ctime; | |
553 | capsnap->time_warp_seq = ci->i_time_warp_seq; | |
554 | if (capsnap->dirty_pages) { | |
819ccbfa | 555 | dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu " |
963b61eb SW |
556 | "still has %d dirty pages\n", inode, capsnap, |
557 | capsnap->context, capsnap->context->seq, | |
819ccbfa SW |
558 | ceph_cap_string(capsnap->dirty), capsnap->size, |
559 | capsnap->dirty_pages); | |
963b61eb SW |
560 | return 0; |
561 | } | |
819ccbfa | 562 | dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu\n", |
963b61eb | 563 | inode, capsnap, capsnap->context, |
819ccbfa SW |
564 | capsnap->context->seq, ceph_cap_string(capsnap->dirty), |
565 | capsnap->size); | |
963b61eb SW |
566 | |
567 | spin_lock(&mdsc->snap_flush_lock); | |
568 | list_add_tail(&ci->i_snap_flush_item, &mdsc->snap_flush_list); | |
569 | spin_unlock(&mdsc->snap_flush_lock); | |
570 | return 1; /* caller may want to ceph_flush_snaps */ | |
571 | } | |
572 | ||
ed326044 SW |
573 | /* |
574 | * Queue cap_snaps for snap writeback for this realm and its children. | |
575 | * Called under snap_rwsem, so realm topology won't change. | |
576 | */ | |
577 | static void queue_realm_cap_snaps(struct ceph_snap_realm *realm) | |
578 | { | |
579 | struct ceph_inode_info *ci; | |
580 | struct inode *lastinode = NULL; | |
581 | struct ceph_snap_realm *child; | |
582 | ||
583 | dout("queue_realm_cap_snaps %p %llx inodes\n", realm, realm->ino); | |
584 | ||
585 | spin_lock(&realm->inodes_with_caps_lock); | |
586 | list_for_each_entry(ci, &realm->inodes_with_caps, | |
587 | i_snap_realm_item) { | |
588 | struct inode *inode = igrab(&ci->vfs_inode); | |
589 | if (!inode) | |
590 | continue; | |
591 | spin_unlock(&realm->inodes_with_caps_lock); | |
592 | if (lastinode) | |
593 | iput(lastinode); | |
594 | lastinode = inode; | |
595 | ceph_queue_cap_snap(ci); | |
596 | spin_lock(&realm->inodes_with_caps_lock); | |
597 | } | |
598 | spin_unlock(&realm->inodes_with_caps_lock); | |
599 | if (lastinode) | |
600 | iput(lastinode); | |
601 | ||
e8e1ba96 SW |
602 | list_for_each_entry(child, &realm->children, child_item) { |
603 | dout("queue_realm_cap_snaps %p %llx queue child %p %llx\n", | |
604 | realm, realm->ino, child, child->ino); | |
605 | list_del_init(&child->dirty_item); | |
606 | list_add(&child->dirty_item, &realm->dirty_item); | |
607 | } | |
ed326044 | 608 | |
e8e1ba96 | 609 | list_del_init(&realm->dirty_item); |
ed326044 SW |
610 | dout("queue_realm_cap_snaps %p %llx done\n", realm, realm->ino); |
611 | } | |
963b61eb SW |
612 | |
613 | /* | |
614 | * Parse and apply a snapblob "snap trace" from the MDS. This specifies | |
615 | * the snap realm parameters from a given realm and all of its ancestors, | |
616 | * up to the root. | |
617 | * | |
618 | * Caller must hold snap_rwsem for write. | |
619 | */ | |
620 | int ceph_update_snap_trace(struct ceph_mds_client *mdsc, | |
621 | void *p, void *e, bool deletion) | |
622 | { | |
623 | struct ceph_mds_snap_realm *ri; /* encoded */ | |
624 | __le64 *snaps; /* encoded */ | |
625 | __le64 *prior_parent_snaps; /* encoded */ | |
626 | struct ceph_snap_realm *realm; | |
627 | int invalidate = 0; | |
628 | int err = -ENOMEM; | |
ae00d4f3 | 629 | LIST_HEAD(dirty_realms); |
963b61eb SW |
630 | |
631 | dout("update_snap_trace deletion=%d\n", deletion); | |
632 | more: | |
633 | ceph_decode_need(&p, e, sizeof(*ri), bad); | |
634 | ri = p; | |
635 | p += sizeof(*ri); | |
636 | ceph_decode_need(&p, e, sizeof(u64)*(le32_to_cpu(ri->num_snaps) + | |
637 | le32_to_cpu(ri->num_prior_parent_snaps)), bad); | |
638 | snaps = p; | |
639 | p += sizeof(u64) * le32_to_cpu(ri->num_snaps); | |
640 | prior_parent_snaps = p; | |
641 | p += sizeof(u64) * le32_to_cpu(ri->num_prior_parent_snaps); | |
642 | ||
643 | realm = ceph_lookup_snap_realm(mdsc, le64_to_cpu(ri->ino)); | |
963b61eb SW |
644 | if (!realm) { |
645 | realm = ceph_create_snap_realm(mdsc, le64_to_cpu(ri->ino)); | |
646 | if (IS_ERR(realm)) { | |
647 | err = PTR_ERR(realm); | |
648 | goto fail; | |
649 | } | |
650 | } | |
651 | ||
963b61eb SW |
652 | /* ensure the parent is correct */ |
653 | err = adjust_snap_realm_parent(mdsc, realm, le64_to_cpu(ri->parent)); | |
654 | if (err < 0) | |
655 | goto fail; | |
656 | invalidate += err; | |
657 | ||
658 | if (le64_to_cpu(ri->seq) > realm->seq) { | |
ae00d4f3 SW |
659 | dout("update_snap_trace updating %llx %p %lld -> %lld\n", |
660 | realm->ino, realm, realm->seq, le64_to_cpu(ri->seq)); | |
963b61eb SW |
661 | /* update realm parameters, snap lists */ |
662 | realm->seq = le64_to_cpu(ri->seq); | |
663 | realm->created = le64_to_cpu(ri->created); | |
664 | realm->parent_since = le64_to_cpu(ri->parent_since); | |
665 | ||
666 | realm->num_snaps = le32_to_cpu(ri->num_snaps); | |
667 | err = dup_array(&realm->snaps, snaps, realm->num_snaps); | |
668 | if (err < 0) | |
669 | goto fail; | |
670 | ||
671 | realm->num_prior_parent_snaps = | |
672 | le32_to_cpu(ri->num_prior_parent_snaps); | |
673 | err = dup_array(&realm->prior_parent_snaps, prior_parent_snaps, | |
674 | realm->num_prior_parent_snaps); | |
675 | if (err < 0) | |
676 | goto fail; | |
677 | ||
ae00d4f3 SW |
678 | /* queue realm for cap_snap creation */ |
679 | list_add(&realm->dirty_item, &dirty_realms); | |
680 | ||
963b61eb SW |
681 | invalidate = 1; |
682 | } else if (!realm->cached_context) { | |
ae00d4f3 SW |
683 | dout("update_snap_trace %llx %p seq %lld new\n", |
684 | realm->ino, realm, realm->seq); | |
963b61eb | 685 | invalidate = 1; |
ae00d4f3 SW |
686 | } else { |
687 | dout("update_snap_trace %llx %p seq %lld unchanged\n", | |
688 | realm->ino, realm, realm->seq); | |
963b61eb SW |
689 | } |
690 | ||
691 | dout("done with %llx %p, invalidated=%d, %p %p\n", realm->ino, | |
692 | realm, invalidate, p, e); | |
693 | ||
694 | if (p < e) | |
695 | goto more; | |
696 | ||
697 | /* invalidate when we reach the _end_ (root) of the trace */ | |
698 | if (invalidate) | |
699 | rebuild_snap_realms(realm); | |
700 | ||
ae00d4f3 SW |
701 | /* |
702 | * queue cap snaps _after_ we've built the new snap contexts, | |
703 | * so that i_head_snapc can be set appropriately. | |
704 | */ | |
e8e1ba96 SW |
705 | while (!list_empty(&dirty_realms)) { |
706 | realm = list_first_entry(&dirty_realms, struct ceph_snap_realm, | |
707 | dirty_item); | |
ae00d4f3 SW |
708 | queue_realm_cap_snaps(realm); |
709 | } | |
710 | ||
963b61eb SW |
711 | __cleanup_empty_realms(mdsc); |
712 | return 0; | |
713 | ||
714 | bad: | |
715 | err = -EINVAL; | |
716 | fail: | |
717 | pr_err("update_snap_trace error %d\n", err); | |
718 | return err; | |
719 | } | |
720 | ||
721 | ||
722 | /* | |
723 | * Send any cap_snaps that are queued for flush. Try to carry | |
724 | * s_mutex across multiple snap flushes to avoid locking overhead. | |
725 | * | |
726 | * Caller holds no locks. | |
727 | */ | |
728 | static void flush_snaps(struct ceph_mds_client *mdsc) | |
729 | { | |
730 | struct ceph_inode_info *ci; | |
731 | struct inode *inode; | |
732 | struct ceph_mds_session *session = NULL; | |
733 | ||
734 | dout("flush_snaps\n"); | |
735 | spin_lock(&mdsc->snap_flush_lock); | |
736 | while (!list_empty(&mdsc->snap_flush_list)) { | |
737 | ci = list_first_entry(&mdsc->snap_flush_list, | |
738 | struct ceph_inode_info, i_snap_flush_item); | |
739 | inode = &ci->vfs_inode; | |
70b666c3 | 740 | ihold(inode); |
963b61eb | 741 | spin_unlock(&mdsc->snap_flush_lock); |
be655596 | 742 | spin_lock(&ci->i_ceph_lock); |
e835124c | 743 | __ceph_flush_snaps(ci, &session, 0); |
be655596 | 744 | spin_unlock(&ci->i_ceph_lock); |
963b61eb SW |
745 | iput(inode); |
746 | spin_lock(&mdsc->snap_flush_lock); | |
747 | } | |
748 | spin_unlock(&mdsc->snap_flush_lock); | |
749 | ||
750 | if (session) { | |
751 | mutex_unlock(&session->s_mutex); | |
752 | ceph_put_mds_session(session); | |
753 | } | |
754 | dout("flush_snaps done\n"); | |
755 | } | |
756 | ||
757 | ||
758 | /* | |
759 | * Handle a snap notification from the MDS. | |
760 | * | |
761 | * This can take two basic forms: the simplest is just a snap creation | |
762 | * or deletion notification on an existing realm. This should update the | |
763 | * realm and its children. | |
764 | * | |
765 | * The more difficult case is realm creation, due to snap creation at a | |
766 | * new point in the file hierarchy, or due to a rename that moves a file or | |
767 | * directory into another realm. | |
768 | */ | |
769 | void ceph_handle_snap(struct ceph_mds_client *mdsc, | |
2600d2dd | 770 | struct ceph_mds_session *session, |
963b61eb SW |
771 | struct ceph_msg *msg) |
772 | { | |
3d14c5d2 | 773 | struct super_block *sb = mdsc->fsc->sb; |
2600d2dd | 774 | int mds = session->s_mds; |
963b61eb SW |
775 | u64 split; |
776 | int op; | |
777 | int trace_len; | |
778 | struct ceph_snap_realm *realm = NULL; | |
779 | void *p = msg->front.iov_base; | |
780 | void *e = p + msg->front.iov_len; | |
781 | struct ceph_mds_snap_head *h; | |
782 | int num_split_inos, num_split_realms; | |
783 | __le64 *split_inos = NULL, *split_realms = NULL; | |
784 | int i; | |
785 | int locked_rwsem = 0; | |
786 | ||
963b61eb SW |
787 | /* decode */ |
788 | if (msg->front.iov_len < sizeof(*h)) | |
789 | goto bad; | |
790 | h = p; | |
791 | op = le32_to_cpu(h->op); | |
792 | split = le64_to_cpu(h->split); /* non-zero if we are splitting an | |
793 | * existing realm */ | |
794 | num_split_inos = le32_to_cpu(h->num_split_inos); | |
795 | num_split_realms = le32_to_cpu(h->num_split_realms); | |
796 | trace_len = le32_to_cpu(h->trace_len); | |
797 | p += sizeof(*h); | |
798 | ||
799 | dout("handle_snap from mds%d op %s split %llx tracelen %d\n", mds, | |
800 | ceph_snap_op_name(op), split, trace_len); | |
801 | ||
963b61eb SW |
802 | mutex_lock(&session->s_mutex); |
803 | session->s_seq++; | |
804 | mutex_unlock(&session->s_mutex); | |
805 | ||
806 | down_write(&mdsc->snap_rwsem); | |
807 | locked_rwsem = 1; | |
808 | ||
809 | if (op == CEPH_SNAP_OP_SPLIT) { | |
810 | struct ceph_mds_snap_realm *ri; | |
811 | ||
812 | /* | |
813 | * A "split" breaks part of an existing realm off into | |
814 | * a new realm. The MDS provides a list of inodes | |
815 | * (with caps) and child realms that belong to the new | |
816 | * child. | |
817 | */ | |
818 | split_inos = p; | |
819 | p += sizeof(u64) * num_split_inos; | |
820 | split_realms = p; | |
821 | p += sizeof(u64) * num_split_realms; | |
822 | ceph_decode_need(&p, e, sizeof(*ri), bad); | |
823 | /* we will peek at realm info here, but will _not_ | |
824 | * advance p, as the realm update will occur below in | |
825 | * ceph_update_snap_trace. */ | |
826 | ri = p; | |
827 | ||
828 | realm = ceph_lookup_snap_realm(mdsc, split); | |
963b61eb SW |
829 | if (!realm) { |
830 | realm = ceph_create_snap_realm(mdsc, split); | |
831 | if (IS_ERR(realm)) | |
832 | goto out; | |
833 | } | |
834 | ceph_get_snap_realm(mdsc, realm); | |
835 | ||
836 | dout("splitting snap_realm %llx %p\n", realm->ino, realm); | |
837 | for (i = 0; i < num_split_inos; i++) { | |
838 | struct ceph_vino vino = { | |
839 | .ino = le64_to_cpu(split_inos[i]), | |
840 | .snap = CEPH_NOSNAP, | |
841 | }; | |
842 | struct inode *inode = ceph_find_inode(sb, vino); | |
843 | struct ceph_inode_info *ci; | |
ae00d4f3 | 844 | struct ceph_snap_realm *oldrealm; |
963b61eb SW |
845 | |
846 | if (!inode) | |
847 | continue; | |
848 | ci = ceph_inode(inode); | |
849 | ||
be655596 | 850 | spin_lock(&ci->i_ceph_lock); |
963b61eb SW |
851 | if (!ci->i_snap_realm) |
852 | goto skip_inode; | |
853 | /* | |
854 | * If this inode belongs to a realm that was | |
855 | * created after our new realm, we experienced | |
856 | * a race (due to another split notifications | |
857 | * arriving from a different MDS). So skip | |
858 | * this inode. | |
859 | */ | |
860 | if (ci->i_snap_realm->created > | |
861 | le64_to_cpu(ri->created)) { | |
862 | dout(" leaving %p in newer realm %llx %p\n", | |
863 | inode, ci->i_snap_realm->ino, | |
864 | ci->i_snap_realm); | |
865 | goto skip_inode; | |
866 | } | |
867 | dout(" will move %p to split realm %llx %p\n", | |
868 | inode, realm->ino, realm); | |
869 | /* | |
ae00d4f3 | 870 | * Move the inode to the new realm |
963b61eb | 871 | */ |
052bb34a | 872 | spin_lock(&realm->inodes_with_caps_lock); |
963b61eb | 873 | list_del_init(&ci->i_snap_realm_item); |
ae00d4f3 SW |
874 | list_add(&ci->i_snap_realm_item, |
875 | &realm->inodes_with_caps); | |
876 | oldrealm = ci->i_snap_realm; | |
877 | ci->i_snap_realm = realm; | |
052bb34a | 878 | spin_unlock(&realm->inodes_with_caps_lock); |
be655596 | 879 | spin_unlock(&ci->i_ceph_lock); |
963b61eb | 880 | |
ae00d4f3 SW |
881 | ceph_get_snap_realm(mdsc, realm); |
882 | ceph_put_snap_realm(mdsc, oldrealm); | |
963b61eb SW |
883 | |
884 | iput(inode); | |
885 | continue; | |
886 | ||
887 | skip_inode: | |
be655596 | 888 | spin_unlock(&ci->i_ceph_lock); |
963b61eb SW |
889 | iput(inode); |
890 | } | |
891 | ||
892 | /* we may have taken some of the old realm's children. */ | |
893 | for (i = 0; i < num_split_realms; i++) { | |
894 | struct ceph_snap_realm *child = | |
895 | ceph_lookup_snap_realm(mdsc, | |
896 | le64_to_cpu(split_realms[i])); | |
963b61eb SW |
897 | if (!child) |
898 | continue; | |
899 | adjust_snap_realm_parent(mdsc, child, realm->ino); | |
900 | } | |
901 | } | |
902 | ||
903 | /* | |
904 | * update using the provided snap trace. if we are deleting a | |
905 | * snap, we can avoid queueing cap_snaps. | |
906 | */ | |
907 | ceph_update_snap_trace(mdsc, p, e, | |
908 | op == CEPH_SNAP_OP_DESTROY); | |
909 | ||
ae00d4f3 | 910 | if (op == CEPH_SNAP_OP_SPLIT) |
963b61eb SW |
911 | /* we took a reference when we created the realm, above */ |
912 | ceph_put_snap_realm(mdsc, realm); | |
963b61eb SW |
913 | |
914 | __cleanup_empty_realms(mdsc); | |
915 | ||
916 | up_write(&mdsc->snap_rwsem); | |
917 | ||
918 | flush_snaps(mdsc); | |
919 | return; | |
920 | ||
921 | bad: | |
922 | pr_err("corrupt snap message from mds%d\n", mds); | |
9ec7cab1 | 923 | ceph_msg_dump(msg); |
963b61eb SW |
924 | out: |
925 | if (locked_rwsem) | |
926 | up_write(&mdsc->snap_rwsem); | |
927 | return; | |
928 | } | |
929 | ||
930 | ||
931 |