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authorLi Zefan <lizf@cn.fujitsu.com>2011-11-20 07:33:38 -0500
committerChris Mason <chris.mason@oracle.com>2011-11-20 07:42:14 -0500
commit0f0fbf1d0e188d129756e9508090af4bdbfde00b (patch)
tree1c015e7be1e1ede9b2b654cb6264217fc110e598 /fs/btrfs
parent32240a913d9f3a5aad42175d7696590ea1bfdb08 (diff)
downloadlinux-0f0fbf1d0e188d129756e9508090af4bdbfde00b.tar.gz
Btrfs: fix to search one more bitmap for cluster setup
Suppose there are two bitmaps [0, 256], [256, 512] and one extent
[100, 120] in the free space cache, and we want to setup a cluster
with offset=100, bytes=50.

In this case, there will be only one bitmap [256, 512] in the temporary
bitmaps list, and then setup_cluster_bitmap() won't search bitmap [0, 256].

The cause is, the list is constructed in setup_cluster_no_bitmap(),
and only bitmaps with bitmap_entry->offset >= offset will be added
into the list, and the very bitmap that convers offset has
bitmap_entry->offset <= offset.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/free-space-cache.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 181760f9d2ab..8f792f41feab 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -2453,11 +2453,23 @@ setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
 	struct btrfs_free_space *entry;
 	struct rb_node *node;
 	int ret = -ENOSPC;
+	u64 bitmap_offset = offset_to_bitmap(ctl, offset);
 
 	if (ctl->total_bitmaps == 0)
 		return -ENOSPC;
 
 	/*
+	 * The bitmap that covers offset won't be in the list unless offset
+	 * is just its start offset.
+	 */
+	entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
+	if (entry->offset != bitmap_offset) {
+		entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
+		if (entry && list_empty(&entry->list))
+			list_add(&entry->list, bitmaps);
+	}
+
+	/*
 	 * First check our cached list of bitmaps and see if there is an entry
 	 * here that will work.
 	 */