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authorFilipe Manana <fdmanana@suse.com>2014-12-04 15:31:01 +0000
committerChris Mason <clm@fb.com>2014-12-10 12:22:28 -0800
commita1e7e16ed36b9b059c5ee94e372287418e2dc7bc (patch)
treef18b60f14d1601891aed8e978b66adb617b90d06 /fs
parent9627aeee3e203e30679549e4962633698a6bf87f (diff)
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Btrfs: ensure deletion from pinned_chunks list is protected
The call to remove_extent_mapping() actually deletes the extent map from the list it's included in - fs_info->pinned_chunks - and that list is protected by the chunk mutex. Therefore make that call while holding the chunk mutex and remove the redundant list delete call because it's a noop. This fixes an overlook of the patch titled "Btrfs: fix race between fs trimming and block group remove/allocation" following the same obvervation from the patch titled "Btrfs: fix unprotected deletion from pending_chunks list". Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/free-space-cache.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 030847bf7cec..edf32c5bbef1 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -3185,16 +3185,18 @@ out:
spin_unlock(&block_group->lock);
+ lock_chunks(block_group->fs_info->chunk_root);
em_tree = &block_group->fs_info->mapping_tree.map_tree;
write_lock(&em_tree->lock);
em = lookup_extent_mapping(em_tree, block_group->key.objectid,
1);
BUG_ON(!em); /* logic error, can't happen */
+ /*
+ * remove_extent_mapping() will delete us from the pinned_chunks
+ * list, which is protected by the chunk mutex.
+ */
remove_extent_mapping(em_tree, em);
write_unlock(&em_tree->lock);
-
- lock_chunks(block_group->fs_info->chunk_root);
- list_del_init(&em->list);
unlock_chunks(block_group->fs_info->chunk_root);
/* once for us and once for the tree */