From: Joe Thornber ejt@redhat.com
[ Upstream commit 5faafc77f7de69147d1e818026b9a0cbf036a7b2 ]
Current commit code resets the place where the search for free blocks will begin back to the start of the metadata device. There are a couple of repercussions to this:
- The first allocation after the commit is likely to take longer than normal as it searches for a free block in an area that is likely to have very few free blocks (if any).
- Any free blocks it finds will have been recently freed. Reusing them means we have fewer old copies of the metadata to aid recovery from hardware error.
Fix these issues by leaving the cursor alone, only resetting when the search hits the end of the metadata device.
Signed-off-by: Joe Thornber ejt@redhat.com Signed-off-by: Mike Snitzer snitzer@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/md/persistent-data/dm-space-map-disk.c | 9 ++++++++- drivers/md/persistent-data/dm-space-map-metadata.c | 9 ++++++++- 2 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/drivers/md/persistent-data/dm-space-map-disk.c b/drivers/md/persistent-data/dm-space-map-disk.c index bf4c5e2ccb6f..e0acae7a3815 100644 --- a/drivers/md/persistent-data/dm-space-map-disk.c +++ b/drivers/md/persistent-data/dm-space-map-disk.c @@ -171,6 +171,14 @@ static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b) * Any block we allocate has to be free in both the old and current ll. */ r = sm_ll_find_common_free_block(&smd->old_ll, &smd->ll, smd->begin, smd->ll.nr_blocks, b); + if (r == -ENOSPC) { + /* + * There's no free block between smd->begin and the end of the metadata device. + * We search before smd->begin in case something has been freed. + */ + r = sm_ll_find_common_free_block(&smd->old_ll, &smd->ll, 0, smd->begin, b); + } + if (r) return r;
@@ -199,7 +207,6 @@ static int sm_disk_commit(struct dm_space_map *sm) return r;
memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll)); - smd->begin = 0; smd->nr_allocated_this_transaction = 0;
r = sm_disk_get_nr_free(sm, &nr_free); diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c index 9e3c64ec2026..da439ac85796 100644 --- a/drivers/md/persistent-data/dm-space-map-metadata.c +++ b/drivers/md/persistent-data/dm-space-map-metadata.c @@ -452,6 +452,14 @@ static int sm_metadata_new_block_(struct dm_space_map *sm, dm_block_t *b) * Any block we allocate has to be free in both the old and current ll. */ r = sm_ll_find_common_free_block(&smm->old_ll, &smm->ll, smm->begin, smm->ll.nr_blocks, b); + if (r == -ENOSPC) { + /* + * There's no free block between smm->begin and the end of the metadata device. + * We search before smm->begin in case something has been freed. + */ + r = sm_ll_find_common_free_block(&smm->old_ll, &smm->ll, 0, smm->begin, b); + } + if (r) return r;
@@ -503,7 +511,6 @@ static int sm_metadata_commit(struct dm_space_map *sm) return r;
memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll)); - smm->begin = 0; smm->allocated_this_transaction = 0;
return 0;