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(&realm
->empty_item
, &mdsc
->snap_empty
);
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
;
299 u32 num
= realm
->num_prior_parent_snaps
+ realm
->num_snaps
;
302 * build parent context, if it hasn't been built.
303 * conservatively estimate that all parent snaps might be
307 if (!parent
->cached_context
) {
308 err
= build_snap_context(parent
);
312 num
+= parent
->cached_context
->num_snaps
;
315 /* do i actually need to update? not if my context seq
316 matches realm seq, and my parents' does to. (this works
317 because we rebuild_snap_realms() works _downward_ in
318 hierarchy after each update.) */
319 if (realm
->cached_context
&&
320 realm
->cached_context
->seq
== realm
->seq
&&
322 realm
->cached_context
->seq
>= parent
->cached_context
->seq
)) {
323 dout("build_snap_context %llx %p: %p seq %lld (%u snaps)"
325 realm
->ino
, realm
, realm
->cached_context
,
326 realm
->cached_context
->seq
,
327 (unsigned int) realm
->cached_context
->num_snaps
);
331 /* alloc new snap context */
333 if (num
> (SIZE_MAX
- sizeof(*snapc
)) / sizeof(u64
))
335 snapc
= ceph_create_snap_context(num
, GFP_NOFS
);
339 /* build (reverse sorted) snap vector */
341 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 (%u snaps)\n",
365 realm
->ino
, realm
, snapc
, snapc
->seq
,
366 (unsigned int) snapc
->num_snaps
);
368 if (realm
->cached_context
)
369 ceph_put_snap_context(realm
->cached_context
);
370 realm
->cached_context
= snapc
;
375 * if we fail, clear old (incorrect) cached_context... hopefully
376 * we'll have better luck building it later
378 if (realm
->cached_context
) {
379 ceph_put_snap_context(realm
->cached_context
);
380 realm
->cached_context
= NULL
;
382 pr_err("build_snap_context %llx %p fail %d\n", realm
->ino
,
388 * rebuild snap context for the given realm and all of its children.
390 static void rebuild_snap_realms(struct ceph_snap_realm
*realm
)
392 struct ceph_snap_realm
*child
;
394 dout("rebuild_snap_realms %llx %p\n", realm
->ino
, realm
);
395 build_snap_context(realm
);
397 list_for_each_entry(child
, &realm
->children
, child_item
)
398 rebuild_snap_realms(child
);
403 * helper to allocate and decode an array of snapids. free prior
406 static int dup_array(u64
**dst
, __le64
*src
, u32 num
)
412 *dst
= kcalloc(num
, sizeof(u64
), GFP_NOFS
);
415 for (i
= 0; i
< num
; i
++)
416 (*dst
)[i
] = get_unaligned_le64(src
+ i
);
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.
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().
435 * Caller must hold snap_rwsem for read (i.e., the realm topology won't
438 void ceph_queue_cap_snap(struct ceph_inode_info
*ci
)
440 struct inode
*inode
= &ci
->vfs_inode
;
441 struct ceph_cap_snap
*capsnap
;
444 capsnap
= kzalloc(sizeof(*capsnap
), GFP_NOFS
);
446 pr_err("ENOMEM allocating ceph_cap_snap on %p\n", inode
);
450 spin_lock(&ci
->i_ceph_lock
);
451 used
= __ceph_caps_used(ci
);
452 dirty
= __ceph_caps_dirty(ci
);
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.
459 if (used
& CEPH_CAP_FILE_WR
)
460 dirty
|= CEPH_CAP_FILE_WR
;
462 if (__ceph_have_pending_cap_snap(ci
)) {
463 /* there is no point in queuing multiple "pending" cap_snaps,
464 as no new writes are allowed to start when pending, so any
465 writes in progress now were started before the previous
466 cap_snap. lucky us. */
467 dout("queue_cap_snap %p already pending\n", inode
);
469 } else if (dirty
& (CEPH_CAP_AUTH_EXCL
|CEPH_CAP_XATTR_EXCL
|
470 CEPH_CAP_FILE_EXCL
|CEPH_CAP_FILE_WR
)) {
471 struct ceph_snap_context
*snapc
= ci
->i_head_snapc
;
474 * if we are a sync write, we may need to go to the snaprealm
475 * to get the current snapc.
478 snapc
= ci
->i_snap_realm
->cached_context
;
480 dout("queue_cap_snap %p cap_snap %p queuing under %p %s\n",
481 inode
, capsnap
, snapc
, ceph_cap_string(dirty
));
484 atomic_set(&capsnap
->nref
, 1);
486 INIT_LIST_HEAD(&capsnap
->ci_item
);
487 INIT_LIST_HEAD(&capsnap
->flushing_item
);
489 capsnap
->follows
= snapc
->seq
;
490 capsnap
->issued
= __ceph_caps_issued(ci
, NULL
);
491 capsnap
->dirty
= dirty
;
493 capsnap
->mode
= inode
->i_mode
;
494 capsnap
->uid
= inode
->i_uid
;
495 capsnap
->gid
= inode
->i_gid
;
497 if (dirty
& CEPH_CAP_XATTR_EXCL
) {
498 __ceph_build_xattrs_blob(ci
);
499 capsnap
->xattr_blob
=
500 ceph_buffer_get(ci
->i_xattrs
.blob
);
501 capsnap
->xattr_version
= ci
->i_xattrs
.version
;
503 capsnap
->xattr_blob
= NULL
;
504 capsnap
->xattr_version
= 0;
507 /* dirty page count moved from _head to this cap_snap;
508 all subsequent writes page dirties occur _after_ this
510 capsnap
->dirty_pages
= ci
->i_wrbuffer_ref_head
;
511 ci
->i_wrbuffer_ref_head
= 0;
512 capsnap
->context
= snapc
;
514 ceph_get_snap_context(ci
->i_snap_realm
->cached_context
);
515 dout(" new snapc is %p\n", ci
->i_head_snapc
);
516 list_add_tail(&capsnap
->ci_item
, &ci
->i_cap_snaps
);
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;
524 /* note mtime, size NOW. */
525 __ceph_finish_cap_snap(ci
, capsnap
);
528 dout("queue_cap_snap %p nothing dirty|writing\n", inode
);
532 spin_unlock(&ci
->i_ceph_lock
);
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.
539 * If capsnap can now be flushed, add to snap_flush list, and return 1.
541 * Caller must hold i_ceph_lock.
543 int __ceph_finish_cap_snap(struct ceph_inode_info
*ci
,
544 struct ceph_cap_snap
*capsnap
)
546 struct inode
*inode
= &ci
->vfs_inode
;
547 struct ceph_mds_client
*mdsc
= ceph_sb_to_client(inode
->i_sb
)->mdsc
;
549 BUG_ON(capsnap
->writing
);
550 capsnap
->size
= inode
->i_size
;
551 capsnap
->mtime
= inode
->i_mtime
;
552 capsnap
->atime
= inode
->i_atime
;
553 capsnap
->ctime
= inode
->i_ctime
;
554 capsnap
->time_warp_seq
= ci
->i_time_warp_seq
;
555 if (capsnap
->dirty_pages
) {
556 dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu "
557 "still has %d dirty pages\n", inode
, capsnap
,
558 capsnap
->context
, capsnap
->context
->seq
,
559 ceph_cap_string(capsnap
->dirty
), capsnap
->size
,
560 capsnap
->dirty_pages
);
563 dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu\n",
564 inode
, capsnap
, capsnap
->context
,
565 capsnap
->context
->seq
, ceph_cap_string(capsnap
->dirty
),
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 */
575 * Queue cap_snaps for snap writeback for this realm and its children.
576 * Called under snap_rwsem, so realm topology won't change.
578 static void queue_realm_cap_snaps(struct ceph_snap_realm
*realm
)
580 struct ceph_inode_info
*ci
;
581 struct inode
*lastinode
= NULL
;
582 struct ceph_snap_realm
*child
;
584 dout("queue_realm_cap_snaps %p %llx inodes\n", realm
, realm
->ino
);
586 spin_lock(&realm
->inodes_with_caps_lock
);
587 list_for_each_entry(ci
, &realm
->inodes_with_caps
,
589 struct inode
*inode
= igrab(&ci
->vfs_inode
);
592 spin_unlock(&realm
->inodes_with_caps_lock
);
596 ceph_queue_cap_snap(ci
);
597 spin_lock(&realm
->inodes_with_caps_lock
);
599 spin_unlock(&realm
->inodes_with_caps_lock
);
603 list_for_each_entry(child
, &realm
->children
, child_item
) {
604 dout("queue_realm_cap_snaps %p %llx queue child %p %llx\n",
605 realm
, realm
->ino
, child
, child
->ino
);
606 list_del_init(&child
->dirty_item
);
607 list_add(&child
->dirty_item
, &realm
->dirty_item
);
610 list_del_init(&realm
->dirty_item
);
611 dout("queue_realm_cap_snaps %p %llx done\n", realm
, realm
->ino
);
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,
619 * Caller must hold snap_rwsem for write.
621 int ceph_update_snap_trace(struct ceph_mds_client
*mdsc
,
622 void *p
, void *e
, bool deletion
)
624 struct ceph_mds_snap_realm
*ri
; /* encoded */
625 __le64
*snaps
; /* encoded */
626 __le64
*prior_parent_snaps
; /* encoded */
627 struct ceph_snap_realm
*realm
;
630 LIST_HEAD(dirty_realms
);
632 dout("update_snap_trace deletion=%d\n", deletion
);
634 ceph_decode_need(&p
, e
, sizeof(*ri
), bad
);
637 ceph_decode_need(&p
, e
, sizeof(u64
)*(le32_to_cpu(ri
->num_snaps
) +
638 le32_to_cpu(ri
->num_prior_parent_snaps
)), bad
);
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
);
644 realm
= ceph_lookup_snap_realm(mdsc
, le64_to_cpu(ri
->ino
));
646 realm
= ceph_create_snap_realm(mdsc
, le64_to_cpu(ri
->ino
));
648 err
= PTR_ERR(realm
);
653 /* ensure the parent is correct */
654 err
= adjust_snap_realm_parent(mdsc
, realm
, le64_to_cpu(ri
->parent
));
659 if (le64_to_cpu(ri
->seq
) > realm
->seq
) {
660 dout("update_snap_trace updating %llx %p %lld -> %lld\n",
661 realm
->ino
, realm
, realm
->seq
, le64_to_cpu(ri
->seq
));
662 /* update realm parameters, snap lists */
663 realm
->seq
= le64_to_cpu(ri
->seq
);
664 realm
->created
= le64_to_cpu(ri
->created
);
665 realm
->parent_since
= le64_to_cpu(ri
->parent_since
);
667 realm
->num_snaps
= le32_to_cpu(ri
->num_snaps
);
668 err
= dup_array(&realm
->snaps
, snaps
, realm
->num_snaps
);
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
);
679 /* queue realm for cap_snap creation */
680 list_add(&realm
->dirty_item
, &dirty_realms
);
683 } else if (!realm
->cached_context
) {
684 dout("update_snap_trace %llx %p seq %lld new\n",
685 realm
->ino
, realm
, realm
->seq
);
688 dout("update_snap_trace %llx %p seq %lld unchanged\n",
689 realm
->ino
, realm
, realm
->seq
);
692 dout("done with %llx %p, invalidated=%d, %p %p\n", realm
->ino
,
693 realm
, invalidate
, p
, e
);
698 /* invalidate when we reach the _end_ (root) of the trace */
700 rebuild_snap_realms(realm
);
703 * queue cap snaps _after_ we've built the new snap contexts,
704 * so that i_head_snapc can be set appropriately.
706 while (!list_empty(&dirty_realms
)) {
707 realm
= list_first_entry(&dirty_realms
, struct ceph_snap_realm
,
709 queue_realm_cap_snaps(realm
);
712 __cleanup_empty_realms(mdsc
);
718 pr_err("update_snap_trace error %d\n", err
);
724 * Send any cap_snaps that are queued for flush. Try to carry
725 * s_mutex across multiple snap flushes to avoid locking overhead.
727 * Caller holds no locks.
729 static void flush_snaps(struct ceph_mds_client
*mdsc
)
731 struct ceph_inode_info
*ci
;
733 struct ceph_mds_session
*session
= NULL
;
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
;
742 spin_unlock(&mdsc
->snap_flush_lock
);
743 spin_lock(&ci
->i_ceph_lock
);
744 __ceph_flush_snaps(ci
, &session
, 0);
745 spin_unlock(&ci
->i_ceph_lock
);
747 spin_lock(&mdsc
->snap_flush_lock
);
749 spin_unlock(&mdsc
->snap_flush_lock
);
752 mutex_unlock(&session
->s_mutex
);
753 ceph_put_mds_session(session
);
755 dout("flush_snaps done\n");
760 * Handle a snap notification from the MDS.
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.
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.
770 void ceph_handle_snap(struct ceph_mds_client
*mdsc
,
771 struct ceph_mds_session
*session
,
772 struct ceph_msg
*msg
)
774 struct super_block
*sb
= mdsc
->fsc
->sb
;
775 int mds
= session
->s_mds
;
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
;
786 int locked_rwsem
= 0;
789 if (msg
->front
.iov_len
< sizeof(*h
))
792 op
= le32_to_cpu(h
->op
);
793 split
= le64_to_cpu(h
->split
); /* non-zero if we are splitting an
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
);
800 dout("handle_snap from mds%d op %s split %llx tracelen %d\n", mds
,
801 ceph_snap_op_name(op
), split
, trace_len
);
803 mutex_lock(&session
->s_mutex
);
805 mutex_unlock(&session
->s_mutex
);
807 down_write(&mdsc
->snap_rwsem
);
810 if (op
== CEPH_SNAP_OP_SPLIT
) {
811 struct ceph_mds_snap_realm
*ri
;
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
820 p
+= sizeof(u64
) * num_split_inos
;
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. */
829 realm
= ceph_lookup_snap_realm(mdsc
, split
);
831 realm
= ceph_create_snap_realm(mdsc
, split
);
835 ceph_get_snap_realm(mdsc
, realm
);
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
]),
843 struct inode
*inode
= ceph_find_inode(sb
, vino
);
844 struct ceph_inode_info
*ci
;
845 struct ceph_snap_realm
*oldrealm
;
849 ci
= ceph_inode(inode
);
851 spin_lock(&ci
->i_ceph_lock
);
852 if (!ci
->i_snap_realm
)
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
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
,
868 dout(" will move %p to split realm %llx %p\n",
869 inode
, realm
->ino
, realm
);
871 * Move the inode to the new realm
873 spin_lock(&realm
->inodes_with_caps_lock
);
874 list_del_init(&ci
->i_snap_realm_item
);
875 list_add(&ci
->i_snap_realm_item
,
876 &realm
->inodes_with_caps
);
877 oldrealm
= ci
->i_snap_realm
;
878 ci
->i_snap_realm
= realm
;
879 spin_unlock(&realm
->inodes_with_caps_lock
);
880 spin_unlock(&ci
->i_ceph_lock
);
882 ceph_get_snap_realm(mdsc
, realm
);
883 ceph_put_snap_realm(mdsc
, oldrealm
);
889 spin_unlock(&ci
->i_ceph_lock
);
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
]));
900 adjust_snap_realm_parent(mdsc
, child
, realm
->ino
);
905 * update using the provided snap trace. if we are deleting a
906 * snap, we can avoid queueing cap_snaps.
908 ceph_update_snap_trace(mdsc
, p
, e
,
909 op
== CEPH_SNAP_OP_DESTROY
);
911 if (op
== CEPH_SNAP_OP_SPLIT
)
912 /* we took a reference when we created the realm, above */
913 ceph_put_snap_realm(mdsc
, realm
);
915 __cleanup_empty_realms(mdsc
);
917 up_write(&mdsc
->snap_rwsem
);
923 pr_err("corrupt snap message from mds%d\n", mds
);
927 up_write(&mdsc
->snap_rwsem
);
This page took 0.048063 seconds and 5 git commands to generate.