5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: liyouhong <redacted>
commit 39c5aa3bd8ec3912d2cd0b3fe092642b0d2b0713 upstream.
metadata_take_snap() bumps the live superblock refcount and then
dm_tm_shadow_block() allocates a new block for the metadata snapshot.
If the subsequent dm_sm_inc_block() of writeset_tree_root or
era_array_root fails, the function only unlocks the clone and
returns. The newly allocated shadow block is never returned to the
metadata space map, so each failed take-snap permanently leaks one
metadata block.
Free the clone with dm_sm_dec_block() on those error paths, matching
the final step of metadata_drop_snap().
Fixes: eec40579d848 ("dm: add era target")
Cc: <redacted>
Signed-off-by: liyouhong <redacted>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/md/dm-era-target.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/drivers/md/dm-era-target.c
+++ b/drivers/md/dm-era-target.c
@@ -1019,6 +1019,7 @@ static int metadata_checkpoint(struct er
static int metadata_take_snap(struct era_metadata *md)
{
int r, inc;
+ dm_block_t location;
struct dm_block *clone;
if (md->metadata_snap != SUPERBLOCK_LOCATION) {@@ -1056,7 +1057,9 @@ static int metadata_take_snap(struct era
r = dm_sm_inc_block(md->sm, md->writeset_tree_root);
if (r) {
DMERR("%s: couldn't inc writeset tree root", __func__);
+ location = dm_block_location(clone);
dm_tm_unlock(md->tm, clone);
+ dm_sm_dec_block(md->sm, location);
return r;
}
@@ -1064,7 +1067,9 @@ static int metadata_take_snap(struct era
if (r) {
DMERR("%s: couldn't inc era tree root", __func__);
dm_sm_dec_block(md->sm, md->writeset_tree_root);
+ location = dm_block_location(clone);
dm_tm_unlock(md->tm, clone);
+ dm_sm_dec_block(md->sm, location);
return r;
}