diff mbox

[02/16] Btrfs: fix space leak when skipping small extents during trimming

Message ID 4E1E5F82.9040506@cn.fujitsu.com (mailing list archive)
State New, archived
Headers show

Commit Message

Li Zefan July 14, 2011, 3:16 a.m. UTC
We're taking a free space extent out of the free space cache, trimming
it and then putting it back into the cache.

However for an extent that is smaller than the specified minimum length,
it's taken out but won't be put back, which causes space leak.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
 fs/btrfs/free-space-cache.c |   34 +++++++++++++++++-----------------
 1 files changed, 17 insertions(+), 17 deletions(-)
diff mbox

Patch

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index bf0d615..901585d 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -2463,6 +2463,7 @@  int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
 	u64 bytes = 0;
 	u64 actually_trimmed;
 	int ret = 0;
+	int update_ret;
 
 	*trimmed = 0;
 
@@ -2486,6 +2487,7 @@  int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
 		}
 
 		if (entry->bitmap) {
+			bytes = 0;
 			ret = search_bitmap(ctl, entry, &start, &bytes);
 			if (!ret) {
 				if (start >= end) {
@@ -2493,6 +2495,8 @@  int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
 					break;
 				}
 				bytes = min(bytes, end - start);
+				if (bytes < minlen)
+					goto next;
 				bitmap_clear_bits(ctl, entry, start, bytes);
 				if (entry->bytes == 0)
 					free_bitmap(ctl, entry);
@@ -2506,33 +2510,29 @@  int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
 		} else {
 			start = entry->offset;
 			bytes = min(entry->bytes, end - start);
+			if (bytes < minlen)
+				goto next;
 			unlink_free_space(ctl, entry);
 			kmem_cache_free(btrfs_free_space_cachep, entry);
 		}
 
 		spin_unlock(&ctl->tree_lock);
 
-		if (bytes >= minlen) {
-			int update_ret;
-			update_ret = btrfs_update_reserved_bytes(block_group,
-								 bytes, 1, 1);
+		update_ret = btrfs_update_reserved_bytes(block_group,
+							 bytes, 1, 1);
 
-			ret = btrfs_error_discard_extent(fs_info->extent_root,
-							 start,
-							 bytes,
-							 &actually_trimmed);
+		ret = btrfs_error_discard_extent(fs_info->extent_root, start,
+						 bytes, &actually_trimmed);
 
-			btrfs_add_free_space(block_group, start, bytes);
-			if (!update_ret)
-				btrfs_update_reserved_bytes(block_group,
-							    bytes, 0, 1);
+		btrfs_add_free_space(block_group, start, bytes);
+		if (!update_ret)
+			btrfs_update_reserved_bytes(block_group, bytes, 0, 1);
 
-			if (ret)
-				break;
-			*trimmed += actually_trimmed;
-		}
+		if (ret)
+			break;
+		*trimmed += actually_trimmed;
+next:
 		start += bytes;
-		bytes = 0;
 
 		if (fatal_signal_pending(current)) {
 			ret = -ERESTARTSYS;