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authorJoe Thornber <ejt@redhat.com>2019-01-15 13:27:01 -0500
committerMike Snitzer <snitzer@redhat.com>2019-01-15 16:10:41 -0500
commitd445bd9cec1a850c2100fcf53684c13b3fd934f2 (patch)
treeabca30179b3fa5355959344f50c57dce9213ef55 /drivers/md/dm-thin.c
parent1856b9f7bcc8e9bdcccc360aabb56fbd4dd6c565 (diff)
dm thin: fix passdown_double_checking_shared_status()
Commit 00a0ea33b495 ("dm thin: do not queue freed thin mapping for next stage processing") changed process_prepared_discard_passdown_pt1() to increment all the blocks being discarded until after the passdown had completed to avoid them being prematurely reused. IO issued to a thin device that breaks sharing with a snapshot, followed by a discard issued to snapshot(s) that previously shared the block(s), results in passdown_double_checking_shared_status() being called to iterate through the blocks double checking their reference count is zero and issuing the passdown if so. So a side effect of commit 00a0ea33b495 is passdown_double_checking_shared_status() was broken. Fix this by checking if the block reference count is greater than 1. Also, rename dm_pool_block_is_used() to dm_pool_block_is_shared(). Fixes: 00a0ea33b495 ("dm thin: do not queue freed thin mapping for next stage processing") Cc: stable@vger.kernel.org # 4.9+ Reported-by: ryan.p.norwood@gmail.com Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-thin.c')
-rw-r--r--drivers/md/dm-thin.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index dadd9696340c..ca8af21bf644 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -1048,7 +1048,7 @@ static void passdown_double_checking_shared_status(struct dm_thin_new_mapping *m
* passdown we have to check that these blocks are now unused.
*/
int r = 0;
- bool used = true;
+ bool shared = true;
struct thin_c *tc = m->tc;
struct pool *pool = tc->pool;
dm_block_t b = m->data_block, e, end = m->data_block + m->virt_end - m->virt_begin;
@@ -1058,11 +1058,11 @@ static void passdown_double_checking_shared_status(struct dm_thin_new_mapping *m
while (b != end) {
/* find start of unmapped run */
for (; b < end; b++) {
- r = dm_pool_block_is_used(pool->pmd, b, &used);
+ r = dm_pool_block_is_shared(pool->pmd, b, &shared);
if (r)
goto out;
- if (!used)
+ if (!shared)
break;
}
@@ -1071,11 +1071,11 @@ static void passdown_double_checking_shared_status(struct dm_thin_new_mapping *m
/* find end of run */
for (e = b + 1; e != end; e++) {
- r = dm_pool_block_is_used(pool->pmd, e, &used);
+ r = dm_pool_block_is_shared(pool->pmd, e, &shared);
if (r)
goto out;
- if (used)
+ if (shared)
break;
}