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| author | Alex Elder <elder@inktank.com> | 2013-01-14 12:43:31 -0600 |
|---|---|---|
| committer | Sage Weil <sage@inktank.com> | 2013-02-13 18:29:10 -0800 |
| commit | 6d292906f80170f4647079dd503df18b737750af (patch) | |
| tree | 2fc2b4f1235375cd143ab261540ce19e56d8ab62 /drivers | |
| parent | 8eb87565306cf40a32f5d0883d008675cd2dd510 (diff) | |
| download | linux-stable-6d292906f80170f4647079dd503df18b737750af.tar.gz linux-stable-6d292906f80170f4647079dd503df18b737750af.tar.bz2 linux-stable-6d292906f80170f4647079dd503df18b737750af.zip | |
rbd: define flags field, use it for exists flag
Define a new rbd device flags field, manipulated using bit
operations. Replace the use of the current "exists" flag with a bit
in this new "flags" field. Add a little commentary about the
"exists" flag, which does not need to be manipulated atomically.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/block/rbd.c | 37 |
1 files changed, 28 insertions, 9 deletions
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index fd9656b5fdb9..8c90a39c2a91 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -264,7 +264,7 @@ struct rbd_device { spinlock_t lock; /* queue lock */ struct rbd_image_header header; - atomic_t exists; + unsigned long flags; struct rbd_spec *spec; char *header_name; @@ -292,6 +292,12 @@ struct rbd_device { unsigned long open_count; }; +/* Flag bits for rbd_dev->flags */ + +enum rbd_dev_flags { + RBD_DEV_FLAG_EXISTS, /* mapped snapshot has not been deleted */ +}; + static DEFINE_MUTEX(ctl_mutex); /* Serialize open/close/setup/teardown */ static LIST_HEAD(rbd_dev_list); /* devices */ @@ -782,7 +788,8 @@ static int rbd_dev_set_mapping(struct rbd_device *rbd_dev) goto done; rbd_dev->mapping.read_only = true; } - atomic_set(&rbd_dev->exists, 1); + set_bit(RBD_DEV_FLAG_EXISTS, &rbd_dev->flags); + done: return ret; } @@ -1877,9 +1884,14 @@ static void rbd_request_fn(struct request_queue *q) rbd_assert(rbd_dev->spec->snap_id == CEPH_NOSNAP); } - /* Quit early if the snapshot has disappeared */ - - if (!atomic_read(&rbd_dev->exists)) { + /* + * Quit early if the mapped snapshot no longer + * exists. It's still possible the snapshot will + * have disappeared by the time our request arrives + * at the osd, but there's no sense in sending it if + * we already know. + */ + if (!test_bit(RBD_DEV_FLAG_EXISTS, &rbd_dev->flags)) { dout("request for non-existent snapshot"); rbd_assert(rbd_dev->spec->snap_id != CEPH_NOSNAP); result = -ENXIO; @@ -2571,7 +2583,7 @@ struct rbd_device *rbd_dev_create(struct rbd_client *rbdc, return NULL; spin_lock_init(&rbd_dev->lock); - atomic_set(&rbd_dev->exists, 0); + rbd_dev->flags = 0; INIT_LIST_HEAD(&rbd_dev->node); INIT_LIST_HEAD(&rbd_dev->snaps); init_rwsem(&rbd_dev->header_rwsem); @@ -3200,10 +3212,17 @@ static int rbd_dev_snaps_update(struct rbd_device *rbd_dev) if (snap_id == CEPH_NOSNAP || (snap && snap->id > snap_id)) { struct list_head *next = links->next; - /* Existing snapshot not in the new snap context */ - + /* + * A previously-existing snapshot is not in + * the new snap context. + * + * If the now missing snapshot is the one the + * image is mapped to, clear its exists flag + * so we can avoid sending any more requests + * to it. + */ if (rbd_dev->spec->snap_id == snap->id) - atomic_set(&rbd_dev->exists, 0); + clear_bit(RBD_DEV_FLAG_EXISTS, &rbd_dev->flags); rbd_remove_snap_dev(snap); dout("%ssnap id %llu has been removed\n", rbd_dev->spec->snap_id == snap->id ? |