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dm space map metadata: fix occasional leak of a metadata block on resize 

The metadata space map has a simplified 'bootstrap' mode that is
operational when extending the space maps.  Whilst in this mode it's
possible for some refcount decrement operations to become queued (eg, as
a result of shadowing one of the bitmap indexes).  These decrements were
not being applied when switching out of bootstrap mode.

The effect of this bug was the leaking of a 4k metadata block.  This is
detected by the latest version of thin_check as a non fatal error.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
hifive-unleashed-5.1
Joe Thornber 2015-06-17 13:35:19 +01:00 committed by Mike Snitzer
parent b1f11aff04
commit 6096d91af0
1 changed files with 35 additions and 15 deletions
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50
drivers/md/persistent-data/dm-space-map-metadata.c
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@ -204,6 +204,27 @@ static void in(struct sm_metadata *smm)
smm->recursion_count++;
}
static int apply_bops(struct sm_metadata *smm)
{
int r = 0;
while (!brb_empty(&smm->uncommitted)) {
struct block_op bop;
r = brb_pop(&smm->uncommitted, &bop);
if (r) {
DMERR("bug in bop ring buffer");
break;
}
r = commit_bop(smm, &bop);
if (r)
break;
}
return r;
}
static int out(struct sm_metadata *smm)
{
int r = 0;
@ -216,21 +237,8 @@ static int out(struct sm_metadata *smm)
return -ENOMEM;
}
if (smm->recursion_count == 1) {
while (!brb_empty(&smm->uncommitted)) {
struct block_op bop;
r = brb_pop(&smm->uncommitted, &bop);
if (r) {
DMERR("bug in bop ring buffer");
break;
}
r = commit_bop(smm, &bop);
if (r)
break;
}
}
if (smm->recursion_count == 1)
apply_bops(smm);
smm->recursion_count--;
@ -704,6 +712,12 @@ static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
}
old_len = smm->begin;
r = apply_bops(smm);
if (r) {
DMERR("%s: apply_bops failed", __func__);
goto out;
}
r = sm_ll_commit(&smm->ll);
if (r)
goto out;
@ -773,6 +787,12 @@ int dm_sm_metadata_create(struct dm_space_map *sm,
if (r)
return r;
r = apply_bops(smm);
if (r) {
DMERR("%s: apply_bops failed", __func__);
return r;
}
return sm_metadata_commit(sm);
}