]>
git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - fs/ceph/snap.c
1 #include <linux/ceph/ceph_debug.h>
3 #include <linux/sort.h>
4 #include <linux/slab.h>
7 #include "mds_client.h"
9 #include <linux/ceph/decode.h>
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
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.
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.
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.
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.
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.
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
58 * increase ref count for the realm
60 * caller must hold snap_rwsem for write.
62 void ceph_get_snap_realm(struct ceph_mds_client
*mdsc
,
63 struct ceph_snap_realm
*realm
)
65 dout("get_realm %p %d -> %d\n", realm
,
66 atomic_read(&realm
->nref
), atomic_read(&realm
->nref
)+1);
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
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
);
79 atomic_inc(&realm
->nref
);
82 static void __insert_snap_realm(struct rb_root
*root
,
83 struct ceph_snap_realm
*new)
85 struct rb_node
**p
= &root
->rb_node
;
86 struct rb_node
*parent
= NULL
;
87 struct ceph_snap_realm
*r
= NULL
;
91 r
= rb_entry(parent
, struct ceph_snap_realm
, node
);
92 if (new->ino
< r
->ino
)
94 else if (new->ino
> r
->ino
)
100 rb_link_node(&new->node
, parent
, p
);
101 rb_insert_color(&new->node
, root
);
105 * create and get the realm rooted at @ino and bump its ref count.
107 * caller must hold snap_rwsem for write.
109 static struct ceph_snap_realm
*ceph_create_snap_realm(
110 struct ceph_mds_client
*mdsc
,
113 struct ceph_snap_realm
*realm
;
115 realm
= kzalloc(sizeof(*realm
), GFP_NOFS
);
117 return ERR_PTR(-ENOMEM
);
119 atomic_set(&realm
->nref
, 0); /* tree does not take a ref */
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
);
133 * lookup the realm rooted at @ino.
135 * caller must hold snap_rwsem for write.
137 struct ceph_snap_realm
*ceph_lookup_snap_realm(struct ceph_mds_client
*mdsc
,
140 struct rb_node
*n
= mdsc
->snap_realms
.rb_node
;
141 struct ceph_snap_realm
*r
;
144 r
= rb_entry(n
, struct ceph_snap_realm
, node
);
147 else if (ino
> r
->ino
)
150 dout("lookup_snap_realm %llx %p\n", r
->ino
, r
);
157 static void __put_snap_realm(struct ceph_mds_client
*mdsc
,
158 struct ceph_snap_realm
*realm
);
161 * called with snap_rwsem (write)
163 static void __destroy_snap_realm(struct ceph_mds_client
*mdsc
,
164 struct ceph_snap_realm
*realm
)
166 dout("__destroy_snap_realm %p %llx\n", realm
, realm
->ino
);
168 rb_erase(&realm
->node
, &mdsc
->snap_realms
);
171 list_del_init(&realm
->child_item
);
172 __put_snap_realm(mdsc
, realm
->parent
);
175 kfree(realm
->prior_parent_snaps
);
177 ceph_put_snap_context(realm
->cached_context
);
182 * caller holds snap_rwsem (write)
184 static void __put_snap_realm(struct ceph_mds_client
*mdsc
,
185 struct ceph_snap_realm
*realm
)
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
);
194 * caller needn't hold any locks
196 void ceph_put_snap_realm(struct ceph_mds_client
*mdsc
,
197 struct ceph_snap_realm
*realm
)
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
))
204 if (down_write_trylock(&mdsc
->snap_rwsem
)) {
205 __destroy_snap_realm(mdsc
, realm
);
206 up_write(&mdsc
->snap_rwsem
);
208 spin_lock(&mdsc
->snap_empty_lock
);
209 list_add(&mdsc
->snap_empty
, &realm
->empty_item
);
210 spin_unlock(&mdsc
->snap_empty_lock
);
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
219 * Called under snap_rwsem (write)
221 static void __cleanup_empty_realms(struct ceph_mds_client
*mdsc
)
223 struct ceph_snap_realm
*realm
;
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
);
234 spin_unlock(&mdsc
->snap_empty_lock
);
237 void ceph_cleanup_empty_realms(struct ceph_mds_client
*mdsc
)
239 down_write(&mdsc
->snap_rwsem
);
240 __cleanup_empty_realms(mdsc
);
241 up_write(&mdsc
->snap_rwsem
);
245 * adjust the parent realm of a given @realm. adjust child list, and parent
246 * pointers, and ref counts appropriately.
248 * return true if parent was changed, 0 if unchanged, <0 on error.
250 * caller must hold snap_rwsem for write.
252 static int adjust_snap_realm_parent(struct ceph_mds_client
*mdsc
,
253 struct ceph_snap_realm
*realm
,
256 struct ceph_snap_realm
*parent
;
258 if (realm
->parent_ino
== parentino
)
261 parent
= ceph_lookup_snap_realm(mdsc
, parentino
);
263 parent
= ceph_create_snap_realm(mdsc
, parentino
);
265 return PTR_ERR(parent
);
267 dout("adjust_snap_realm_parent %llx %p: %llx %p -> %llx %p\n",
268 realm
->ino
, realm
, realm
->parent_ino
, realm
->parent
,
271 list_del_init(&realm
->child_item
);
272 ceph_put_snap_realm(mdsc
, realm
->parent
);
274 realm
->parent_ino
= parentino
;
275 realm
->parent
= parent
;
276 ceph_get_snap_realm(mdsc
, parent
);
277 list_add(&realm
->child_item
, &parent
->children
);
282 static int cmpu64_rev(const void *a
, const void *b
)
284 if (*(u64
*)a
< *(u64
*)b
)
286 if (*(u64
*)a
> *(u64
*)b
)
292 * build the snap context for a given realm.
294 static int build_snap_context(struct ceph_snap_realm
*realm
)
296 struct ceph_snap_realm
*parent
= realm
->parent
;
297 struct ceph_snap_context
*snapc
;
300 int num
= realm
->num_prior_parent_snaps
+ realm
->num_snaps
;
303 * build parent context, if it hasn't been built.
304 * conservatively estimate that all parent snaps might be
308 if (!parent
->cached_context
) {
309 err
= build_snap_context(parent
);
313 num
+= parent
->cached_context
->num_snaps
;
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
&&
321 realm
->cached_context
->seq
== realm
->seq
&&
323 realm
->cached_context
->seq
>= parent
->cached_context
->seq
)) {
324 dout("build_snap_context %llx %p: %p seq %lld (%d snaps)"
326 realm
->ino
, realm
, realm
->cached_context
,
327 realm
->cached_context
->seq
,
328 realm
->cached_context
->num_snaps
);
332 /* alloc new snap context */
334 if (num
> ULONG_MAX
/ sizeof(u64
) - sizeof(*snapc
))
336 snapc
= kzalloc(sizeof(*snapc
) + num
*sizeof(u64
), GFP_NOFS
);
339 atomic_set(&snapc
->nref
, 1);
341 /* build (reverse sorted) snap vector */
343 snapc
->seq
= realm
->seq
;
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
] >=
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
;
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
;
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
);
367 if (realm
->cached_context
)
368 ceph_put_snap_context(realm
->cached_context
);
369 realm
->cached_context
= snapc
;
374 * if we fail, clear old (incorrect) cached_context... hopefully
375 * we'll have better luck building it later
377 if (realm
->cached_context
) {
378 ceph_put_snap_context(realm
->cached_context
);
379 realm
->cached_context
= NULL
;
381 pr_err("build_snap_context %llx %p fail %d\n", realm
->ino
,
387 * rebuild snap context for the given realm and all of its children.
389 static void rebuild_snap_realms(struct ceph_snap_realm
*realm
)
391 struct ceph_snap_realm
*child
;
393 dout("rebuild_snap_realms %llx %p\n", realm
->ino
, realm
);
394 build_snap_context(realm
);
396 list_for_each_entry(child
, &realm
->children
, child_item
)
397 rebuild_snap_realms(child
);
402 * helper to allocate and decode an array of snapids. free prior
405 static int dup_array(u64
**dst
, __le64
*src
, int num
)
411 *dst
= kcalloc(num
, sizeof(u64
), GFP_NOFS
);
414 for (i
= 0; i
< num
; i
++)
415 (*dst
)[i
] = get_unaligned_le64(src
+ i
);
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.
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().
434 * Caller must hold snap_rwsem for read (i.e., the realm topology won't
437 void ceph_queue_cap_snap(struct ceph_inode_info
*ci
)
439 struct inode
*inode
= &ci
->vfs_inode
;
440 struct ceph_cap_snap
*capsnap
;
443 capsnap
= kzalloc(sizeof(*capsnap
), GFP_NOFS
);
445 pr_err("ENOMEM allocating ceph_cap_snap on %p\n", inode
);
449 spin_lock(&inode
->i_lock
);
450 used
= __ceph_caps_used(ci
);
451 dirty
= __ceph_caps_dirty(ci
);
452 if (__ceph_have_pending_cap_snap(ci
)) {
453 /* there is no point in queuing multiple "pending" cap_snaps,
454 as no new writes are allowed to start when pending, so any
455 writes in progress now were started before the previous
456 cap_snap. lucky us. */
457 dout("queue_cap_snap %p already pending\n", inode
);
459 } else if (ci
->i_wrbuffer_ref_head
|| (used
& CEPH_CAP_FILE_WR
) ||
460 (dirty
& (CEPH_CAP_AUTH_EXCL
|CEPH_CAP_XATTR_EXCL
|
461 CEPH_CAP_FILE_EXCL
|CEPH_CAP_FILE_WR
))) {
462 struct ceph_snap_context
*snapc
= ci
->i_head_snapc
;
464 dout("queue_cap_snap %p cap_snap %p queuing under %p\n", inode
,
468 atomic_set(&capsnap
->nref
, 1);
470 INIT_LIST_HEAD(&capsnap
->ci_item
);
471 INIT_LIST_HEAD(&capsnap
->flushing_item
);
473 capsnap
->follows
= snapc
->seq
;
474 capsnap
->issued
= __ceph_caps_issued(ci
, NULL
);
475 capsnap
->dirty
= dirty
;
477 capsnap
->mode
= inode
->i_mode
;
478 capsnap
->uid
= inode
->i_uid
;
479 capsnap
->gid
= inode
->i_gid
;
481 if (dirty
& CEPH_CAP_XATTR_EXCL
) {
482 __ceph_build_xattrs_blob(ci
);
483 capsnap
->xattr_blob
=
484 ceph_buffer_get(ci
->i_xattrs
.blob
);
485 capsnap
->xattr_version
= ci
->i_xattrs
.version
;
487 capsnap
->xattr_blob
= NULL
;
488 capsnap
->xattr_version
= 0;
491 /* dirty page count moved from _head to this cap_snap;
492 all subsequent writes page dirties occur _after_ this
494 capsnap
->dirty_pages
= ci
->i_wrbuffer_ref_head
;
495 ci
->i_wrbuffer_ref_head
= 0;
496 capsnap
->context
= snapc
;
498 ceph_get_snap_context(ci
->i_snap_realm
->cached_context
);
499 dout(" new snapc is %p\n", ci
->i_head_snapc
);
500 list_add_tail(&capsnap
->ci_item
, &ci
->i_cap_snaps
);
502 if (used
& CEPH_CAP_FILE_WR
) {
503 dout("queue_cap_snap %p cap_snap %p snapc %p"
504 " seq %llu used WR, now pending\n", inode
,
505 capsnap
, snapc
, snapc
->seq
);
506 capsnap
->writing
= 1;
508 /* note mtime, size NOW. */
509 __ceph_finish_cap_snap(ci
, capsnap
);
512 dout("queue_cap_snap %p nothing dirty|writing\n", inode
);
516 spin_unlock(&inode
->i_lock
);
520 * Finalize the size, mtime for a cap_snap.. that is, settle on final values
521 * to be used for the snapshot, to be flushed back to the mds.
523 * If capsnap can now be flushed, add to snap_flush list, and return 1.
525 * Caller must hold i_lock.
527 int __ceph_finish_cap_snap(struct ceph_inode_info
*ci
,
528 struct ceph_cap_snap
*capsnap
)
530 struct inode
*inode
= &ci
->vfs_inode
;
531 struct ceph_mds_client
*mdsc
= ceph_sb_to_client(inode
->i_sb
)->mdsc
;
533 BUG_ON(capsnap
->writing
);
534 capsnap
->size
= inode
->i_size
;
535 capsnap
->mtime
= inode
->i_mtime
;
536 capsnap
->atime
= inode
->i_atime
;
537 capsnap
->ctime
= inode
->i_ctime
;
538 capsnap
->time_warp_seq
= ci
->i_time_warp_seq
;
539 if (capsnap
->dirty_pages
) {
540 dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu "
541 "still has %d dirty pages\n", inode
, capsnap
,
542 capsnap
->context
, capsnap
->context
->seq
,
543 ceph_cap_string(capsnap
->dirty
), capsnap
->size
,
544 capsnap
->dirty_pages
);
547 dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu\n",
548 inode
, capsnap
, capsnap
->context
,
549 capsnap
->context
->seq
, ceph_cap_string(capsnap
->dirty
),
552 spin_lock(&mdsc
->snap_flush_lock
);
553 list_add_tail(&ci
->i_snap_flush_item
, &mdsc
->snap_flush_list
);
554 spin_unlock(&mdsc
->snap_flush_lock
);
555 return 1; /* caller may want to ceph_flush_snaps */
559 * Queue cap_snaps for snap writeback for this realm and its children.
560 * Called under snap_rwsem, so realm topology won't change.
562 static void queue_realm_cap_snaps(struct ceph_snap_realm
*realm
)
564 struct ceph_inode_info
*ci
;
565 struct inode
*lastinode
= NULL
;
566 struct ceph_snap_realm
*child
;
568 dout("queue_realm_cap_snaps %p %llx inodes\n", realm
, realm
->ino
);
570 spin_lock(&realm
->inodes_with_caps_lock
);
571 list_for_each_entry(ci
, &realm
->inodes_with_caps
,
573 struct inode
*inode
= igrab(&ci
->vfs_inode
);
576 spin_unlock(&realm
->inodes_with_caps_lock
);
580 ceph_queue_cap_snap(ci
);
581 spin_lock(&realm
->inodes_with_caps_lock
);
583 spin_unlock(&realm
->inodes_with_caps_lock
);
587 list_for_each_entry(child
, &realm
->children
, child_item
) {
588 dout("queue_realm_cap_snaps %p %llx queue child %p %llx\n",
589 realm
, realm
->ino
, child
, child
->ino
);
590 list_del_init(&child
->dirty_item
);
591 list_add(&child
->dirty_item
, &realm
->dirty_item
);
594 list_del_init(&realm
->dirty_item
);
595 dout("queue_realm_cap_snaps %p %llx done\n", realm
, realm
->ino
);
599 * Parse and apply a snapblob "snap trace" from the MDS. This specifies
600 * the snap realm parameters from a given realm and all of its ancestors,
603 * Caller must hold snap_rwsem for write.
605 int ceph_update_snap_trace(struct ceph_mds_client
*mdsc
,
606 void *p
, void *e
, bool deletion
)
608 struct ceph_mds_snap_realm
*ri
; /* encoded */
609 __le64
*snaps
; /* encoded */
610 __le64
*prior_parent_snaps
; /* encoded */
611 struct ceph_snap_realm
*realm
;
614 LIST_HEAD(dirty_realms
);
616 dout("update_snap_trace deletion=%d\n", deletion
);
618 ceph_decode_need(&p
, e
, sizeof(*ri
), bad
);
621 ceph_decode_need(&p
, e
, sizeof(u64
)*(le32_to_cpu(ri
->num_snaps
) +
622 le32_to_cpu(ri
->num_prior_parent_snaps
)), bad
);
624 p
+= sizeof(u64
) * le32_to_cpu(ri
->num_snaps
);
625 prior_parent_snaps
= p
;
626 p
+= sizeof(u64
) * le32_to_cpu(ri
->num_prior_parent_snaps
);
628 realm
= ceph_lookup_snap_realm(mdsc
, le64_to_cpu(ri
->ino
));
630 realm
= ceph_create_snap_realm(mdsc
, le64_to_cpu(ri
->ino
));
632 err
= PTR_ERR(realm
);
637 /* ensure the parent is correct */
638 err
= adjust_snap_realm_parent(mdsc
, realm
, le64_to_cpu(ri
->parent
));
643 if (le64_to_cpu(ri
->seq
) > realm
->seq
) {
644 dout("update_snap_trace updating %llx %p %lld -> %lld\n",
645 realm
->ino
, realm
, realm
->seq
, le64_to_cpu(ri
->seq
));
646 /* update realm parameters, snap lists */
647 realm
->seq
= le64_to_cpu(ri
->seq
);
648 realm
->created
= le64_to_cpu(ri
->created
);
649 realm
->parent_since
= le64_to_cpu(ri
->parent_since
);
651 realm
->num_snaps
= le32_to_cpu(ri
->num_snaps
);
652 err
= dup_array(&realm
->snaps
, snaps
, realm
->num_snaps
);
656 realm
->num_prior_parent_snaps
=
657 le32_to_cpu(ri
->num_prior_parent_snaps
);
658 err
= dup_array(&realm
->prior_parent_snaps
, prior_parent_snaps
,
659 realm
->num_prior_parent_snaps
);
663 /* queue realm for cap_snap creation */
664 list_add(&realm
->dirty_item
, &dirty_realms
);
667 } else if (!realm
->cached_context
) {
668 dout("update_snap_trace %llx %p seq %lld new\n",
669 realm
->ino
, realm
, realm
->seq
);
672 dout("update_snap_trace %llx %p seq %lld unchanged\n",
673 realm
->ino
, realm
, realm
->seq
);
676 dout("done with %llx %p, invalidated=%d, %p %p\n", realm
->ino
,
677 realm
, invalidate
, p
, e
);
682 /* invalidate when we reach the _end_ (root) of the trace */
684 rebuild_snap_realms(realm
);
687 * queue cap snaps _after_ we've built the new snap contexts,
688 * so that i_head_snapc can be set appropriately.
690 while (!list_empty(&dirty_realms
)) {
691 realm
= list_first_entry(&dirty_realms
, struct ceph_snap_realm
,
693 queue_realm_cap_snaps(realm
);
696 __cleanup_empty_realms(mdsc
);
702 pr_err("update_snap_trace error %d\n", err
);
708 * Send any cap_snaps that are queued for flush. Try to carry
709 * s_mutex across multiple snap flushes to avoid locking overhead.
711 * Caller holds no locks.
713 static void flush_snaps(struct ceph_mds_client
*mdsc
)
715 struct ceph_inode_info
*ci
;
717 struct ceph_mds_session
*session
= NULL
;
719 dout("flush_snaps\n");
720 spin_lock(&mdsc
->snap_flush_lock
);
721 while (!list_empty(&mdsc
->snap_flush_list
)) {
722 ci
= list_first_entry(&mdsc
->snap_flush_list
,
723 struct ceph_inode_info
, i_snap_flush_item
);
724 inode
= &ci
->vfs_inode
;
726 spin_unlock(&mdsc
->snap_flush_lock
);
727 spin_lock(&inode
->i_lock
);
728 __ceph_flush_snaps(ci
, &session
, 0);
729 spin_unlock(&inode
->i_lock
);
731 spin_lock(&mdsc
->snap_flush_lock
);
733 spin_unlock(&mdsc
->snap_flush_lock
);
736 mutex_unlock(&session
->s_mutex
);
737 ceph_put_mds_session(session
);
739 dout("flush_snaps done\n");
744 * Handle a snap notification from the MDS.
746 * This can take two basic forms: the simplest is just a snap creation
747 * or deletion notification on an existing realm. This should update the
748 * realm and its children.
750 * The more difficult case is realm creation, due to snap creation at a
751 * new point in the file hierarchy, or due to a rename that moves a file or
752 * directory into another realm.
754 void ceph_handle_snap(struct ceph_mds_client
*mdsc
,
755 struct ceph_mds_session
*session
,
756 struct ceph_msg
*msg
)
758 struct super_block
*sb
= mdsc
->fsc
->sb
;
759 int mds
= session
->s_mds
;
763 struct ceph_snap_realm
*realm
= NULL
;
764 void *p
= msg
->front
.iov_base
;
765 void *e
= p
+ msg
->front
.iov_len
;
766 struct ceph_mds_snap_head
*h
;
767 int num_split_inos
, num_split_realms
;
768 __le64
*split_inos
= NULL
, *split_realms
= NULL
;
770 int locked_rwsem
= 0;
773 if (msg
->front
.iov_len
< sizeof(*h
))
776 op
= le32_to_cpu(h
->op
);
777 split
= le64_to_cpu(h
->split
); /* non-zero if we are splitting an
779 num_split_inos
= le32_to_cpu(h
->num_split_inos
);
780 num_split_realms
= le32_to_cpu(h
->num_split_realms
);
781 trace_len
= le32_to_cpu(h
->trace_len
);
784 dout("handle_snap from mds%d op %s split %llx tracelen %d\n", mds
,
785 ceph_snap_op_name(op
), split
, trace_len
);
787 mutex_lock(&session
->s_mutex
);
789 mutex_unlock(&session
->s_mutex
);
791 down_write(&mdsc
->snap_rwsem
);
794 if (op
== CEPH_SNAP_OP_SPLIT
) {
795 struct ceph_mds_snap_realm
*ri
;
798 * A "split" breaks part of an existing realm off into
799 * a new realm. The MDS provides a list of inodes
800 * (with caps) and child realms that belong to the new
804 p
+= sizeof(u64
) * num_split_inos
;
806 p
+= sizeof(u64
) * num_split_realms
;
807 ceph_decode_need(&p
, e
, sizeof(*ri
), bad
);
808 /* we will peek at realm info here, but will _not_
809 * advance p, as the realm update will occur below in
810 * ceph_update_snap_trace. */
813 realm
= ceph_lookup_snap_realm(mdsc
, split
);
815 realm
= ceph_create_snap_realm(mdsc
, split
);
819 ceph_get_snap_realm(mdsc
, realm
);
821 dout("splitting snap_realm %llx %p\n", realm
->ino
, realm
);
822 for (i
= 0; i
< num_split_inos
; i
++) {
823 struct ceph_vino vino
= {
824 .ino
= le64_to_cpu(split_inos
[i
]),
827 struct inode
*inode
= ceph_find_inode(sb
, vino
);
828 struct ceph_inode_info
*ci
;
829 struct ceph_snap_realm
*oldrealm
;
833 ci
= ceph_inode(inode
);
835 spin_lock(&inode
->i_lock
);
836 if (!ci
->i_snap_realm
)
839 * If this inode belongs to a realm that was
840 * created after our new realm, we experienced
841 * a race (due to another split notifications
842 * arriving from a different MDS). So skip
845 if (ci
->i_snap_realm
->created
>
846 le64_to_cpu(ri
->created
)) {
847 dout(" leaving %p in newer realm %llx %p\n",
848 inode
, ci
->i_snap_realm
->ino
,
852 dout(" will move %p to split realm %llx %p\n",
853 inode
, realm
->ino
, realm
);
855 * Move the inode to the new realm
857 spin_lock(&realm
->inodes_with_caps_lock
);
858 list_del_init(&ci
->i_snap_realm_item
);
859 list_add(&ci
->i_snap_realm_item
,
860 &realm
->inodes_with_caps
);
861 oldrealm
= ci
->i_snap_realm
;
862 ci
->i_snap_realm
= realm
;
863 spin_unlock(&realm
->inodes_with_caps_lock
);
864 spin_unlock(&inode
->i_lock
);
866 ceph_get_snap_realm(mdsc
, realm
);
867 ceph_put_snap_realm(mdsc
, oldrealm
);
873 spin_unlock(&inode
->i_lock
);
877 /* we may have taken some of the old realm's children. */
878 for (i
= 0; i
< num_split_realms
; i
++) {
879 struct ceph_snap_realm
*child
=
880 ceph_lookup_snap_realm(mdsc
,
881 le64_to_cpu(split_realms
[i
]));
884 adjust_snap_realm_parent(mdsc
, child
, realm
->ino
);
889 * update using the provided snap trace. if we are deleting a
890 * snap, we can avoid queueing cap_snaps.
892 ceph_update_snap_trace(mdsc
, p
, e
,
893 op
== CEPH_SNAP_OP_DESTROY
);
895 if (op
== CEPH_SNAP_OP_SPLIT
)
896 /* we took a reference when we created the realm, above */
897 ceph_put_snap_realm(mdsc
, realm
);
899 __cleanup_empty_realms(mdsc
);
901 up_write(&mdsc
->snap_rwsem
);
907 pr_err("corrupt snap message from mds%d\n", mds
);
911 up_write(&mdsc
->snap_rwsem
);