From: Li Zefan Date: Sun, 20 Nov 2011 12:33:38 +0000 (-0500) Subject: Btrfs: fix to search one more bitmap for cluster setup X-Git-Tag: firefly_0821_release~3680^2~3894^2~35 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=0f0fbf1d0e188d129756e9508090af4bdbfde00b;p=firefly-linux-kernel-4.4.55.git 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 Signed-off-by: Chris Mason --- 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 @@ -2453,10 +2453,22 @@ 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.