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authorLinus Torvalds <torvalds@linux-foundation.org>2015-09-02 16:35:26 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-09-02 16:35:26 -0700
commit1e1a4e8f439113b7820bc7150569f685e1cc2b43 (patch)
tree25a201240e619f7d766638fee57d8cfc55ec0bb9 /drivers/md/dm-snap.c
parentd975f309a8b250e67b66eabeb56be6989c783629 (diff)
parentcc7da0ba9c96699592d0a69d7d146ac6adcc18e7 (diff)
Merge tag 'dm-4.3-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper update from Mike Snitzer: - a couple small cleanups in dm-cache, dm-verity, persistent-data's dm-btree, and DM core. - a 4.1-stable fix for dm-cache that fixes the leaking of deferred bio prison cells - a 4.2-stable fix that adds feature reporting for the dm-stats features added in 4.2 - improve DM-snapshot to not invalidate the on-disk snapshot if snapshot device write overflow occurs; but a write overflow triggered through the origin device will still invalidate the snapshot. - optimize DM-thinp's async discard submission a bit now that late bio splitting has been included in block core. - switch DM-cache's SMQ policy lock from using a mutex to a spinlock; improves performance on very low latency devices (eg. NVMe SSD). - document DM RAID 4/5/6's discard support [ I did not pull the slab changes, which weren't appropriate for this tree, and weren't obviously the right thing to do anyway. At the very least they need some discussion and explanation before getting merged. Because not pulling the actual tagged commit but doing a partial pull instead, this merge commit thus also obviously is missing the git signature from the original tag ] * tag 'dm-4.3-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: dm cache: fix use after freeing migrations dm cache: small cleanups related to deferred prison cell cleanup dm cache: fix leaking of deferred bio prison cells dm raid: document RAID 4/5/6 discard support dm stats: report precise_timestamps and histogram in @stats_list output dm thin: optimize async discard submission dm snapshot: don't invalidate on-disk image on snapshot write overflow dm: remove unlikely() before IS_ERR() dm: do not override error code returned from dm_get_device() dm: test return value for DM_MAPIO_SUBMITTED dm verity: remove unused mempool dm cache: move wake_waker() from free_migrations() to where it is needed dm btree remove: remove unused function get_nr_entries() dm btree: remove unused "dm_block_t root" parameter in btree_split_sibling() dm cache policy smq: change the mutex to a spinlock
Diffstat (limited to 'drivers/md/dm-snap.c')
-rw-r--r--drivers/md/dm-snap.c20
1 files changed, 16 insertions, 4 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index d10b6876018e..c0bcd6516dfe 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -63,6 +63,13 @@ struct dm_snapshot {
*/
int valid;
+ /*
+ * The snapshot overflowed because of a write to the snapshot device.
+ * We don't have to invalidate the snapshot in this case, but we need
+ * to prevent further writes.
+ */
+ int snapshot_overflowed;
+
/* Origin writes don't trigger exceptions until this is set */
int active;
@@ -1152,6 +1159,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
s->ti = ti;
s->valid = 1;
+ s->snapshot_overflowed = 0;
s->active = 0;
atomic_set(&s->pending_exceptions_count, 0);
s->exception_start_sequence = 0;
@@ -1301,6 +1309,7 @@ static void __handover_exceptions(struct dm_snapshot *snap_src,
snap_dest->ti->max_io_len = snap_dest->store->chunk_size;
snap_dest->valid = snap_src->valid;
+ snap_dest->snapshot_overflowed = snap_src->snapshot_overflowed;
/*
* Set source invalid to ensure it receives no further I/O.
@@ -1691,7 +1700,7 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio)
* to copy an exception */
down_write(&s->lock);
- if (!s->valid) {
+ if (!s->valid || (unlikely(s->snapshot_overflowed) && bio_rw(bio) == WRITE)) {
r = -EIO;
goto out_unlock;
}
@@ -1715,7 +1724,7 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio)
pe = alloc_pending_exception(s);
down_write(&s->lock);
- if (!s->valid) {
+ if (!s->valid || s->snapshot_overflowed) {
free_pending_exception(pe);
r = -EIO;
goto out_unlock;
@@ -1730,7 +1739,8 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio)
pe = __find_pending_exception(s, pe, chunk);
if (!pe) {
- __invalidate_snapshot(s, -ENOMEM);
+ s->snapshot_overflowed = 1;
+ DMERR("Snapshot overflowed: Unable to allocate exception.");
r = -EIO;
goto out_unlock;
}
@@ -1990,6 +2000,8 @@ static void snapshot_status(struct dm_target *ti, status_type_t type,
DMEMIT("Invalid");
else if (snap->merge_failed)
DMEMIT("Merge failed");
+ else if (snap->snapshot_overflowed)
+ DMEMIT("Overflow");
else {
if (snap->store->type->usage) {
sector_t total_sectors, sectors_allocated,
@@ -2353,7 +2365,7 @@ static struct target_type origin_target = {
static struct target_type snapshot_target = {
.name = "snapshot",
- .version = {1, 13, 0},
+ .version = {1, 14, 0},
.module = THIS_MODULE,
.ctr = snapshot_ctr,
.dtr = snapshot_dtr,