[dm-devel] [PTACH] Revert "dm space maps: don't reset space map allocation cursor when committing"

[Luo Meng]

This reverts commit 5faafc77f7de69147d1e818026b9a0cbf036a7b2.

This commit 5faafc77f7de ("dm space maps: don't reset space map allocation
cursor when committing") change the way to find free block.

But when use ramdisk(not support discard) for thin-pool,and storage
over-commitment. Then constantly create and delete file, can find block
in thin-pool, but can't find block in ramdisk.

So need revert this patch.

Fixes: 5faafc77f7de ("dm space maps: don't reset space map allocation cursor when committing")
Signed-off-by: Luo Meng <luomeng12 at huawei.com>
---
 drivers/md/persistent-data/dm-space-map-disk.c     | 9 +--------
 drivers/md/persistent-data/dm-space-map-metadata.c | 9 +--------
 2 files changed, 2 insertions(+), 16 deletions(-)

diff --git a/drivers/md/persistent-data/dm-space-map-disk.c b/drivers/md/persistent-data/dm-space-map-disk.c
index d0a8d5e73c28..17afbebd9244 100644
--- a/drivers/md/persistent-data/dm-space-map-disk.c
+++ b/drivers/md/persistent-data/dm-space-map-disk.c
@@ -134,14 +134,6 @@ 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;
 
@@ -164,6 +156,7 @@ 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;
 
 	return 0;
diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c
index 392ae26134a4..42920e930dbd 100644
--- a/drivers/md/persistent-data/dm-space-map-metadata.c
+++ b/drivers/md/persistent-data/dm-space-map-metadata.c
@@ -453,14 +453,6 @@ 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;
 
@@ -512,6 +504,7 @@ 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;
-- 
2.31.1