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author | Xue jiufei <xuejiufei@huawei.com> | 2015-06-25 01:55:09 +0200 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-06-25 02:49:39 +0200 |
commit | 099768b0c605f55167c0c211afbfeeeea79b56eb (patch) | |
tree | cad1d0723aca030470f0bfa2cc3f5e690a1853a1 /fs/ocfs2/alloc.c | |
parent | ocfs2: return error when ocfs2_figure_merge_contig_type() fails (diff) | |
download | linux-099768b0c605f55167c0c211afbfeeeea79b56eb.tar.xz linux-099768b0c605f55167c0c211afbfeeeea79b56eb.zip |
ocfs2: remove BUG_ON(!empty_extent) in __ocfs2_rotate_tree_left()
ocfs2_rotate_tree_left() calls __ocfs2_rotate_tree_left() for left
rotation while non-rightmost path containing an empty extent in the leaf
block. __ocfs2_rotate_tree_left() returns -EAGAIN if right subtree having an
empty extent and pass the empty_extent_path to caller. The caller
ocfs2_rotate_tree_left() will restart rotation from the returned path.
It will trigger the BUG_ON(!ocfs2_is_empty_extent) when the et on disk
is as follows:
eb0 is the leaf block of path(say path_a) passed to
ocfs2_rotate_tree_left, which has an empty rec[0].
eb1 is the leaf block of path(say path_b) that just right to path_a, which
has no empty record.
eb2 is the leaf block of path(say path_c) that just right to path_b, which
has an empty rec[0]. And path_c is also the rightmost path.
Now we want to remove the empty rec[0] in eb0:
ocfs2_rotate_tree_left:
-> call __ocfs2_rotate_tree_left with path_a as its input *path*
-> call ocfs2_rotate_subtree_left with path_a as its input
*left_path* and path_b as its input *right_path*. it will move
rec[0] in eb1 to eb0, and rec[0] in eb0 is not empty now.
-> continue to call ocfs2_rotate_subtree_left with path_b as its
input *left_path* and path_c as its input *right_path*, and
return -EAGAIN because eb2 has an empty rec[0]
-> call __ocfs2_rotate_tree_left with path_c as it input, rotate all
records in eb2 to left and return 0.
-> call __ocfs2_rotate_tree_left with path_a as its input, and triggers
the BUG_ON(!ocfs2_is_empty_extent) as the rec[0] in eb0 is not empty.
So the BUG_ON() should be removed and return 0 if rec[0] is no longer an
empty extent.
Signed-off-by: joyce.xue <xuejiufei@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
-rw-r--r-- | fs/ocfs2/alloc.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c index ea4c822531cc..5997c00a1515 100644 --- a/fs/ocfs2/alloc.c +++ b/fs/ocfs2/alloc.c @@ -2925,7 +2925,8 @@ static int __ocfs2_rotate_tree_left(handle_t *handle, struct ocfs2_path *right_path = NULL; struct super_block *sb = ocfs2_metadata_cache_get_super(et->et_ci); - BUG_ON(!ocfs2_is_empty_extent(&(path_leaf_el(path)->l_recs[0]))); + if (!ocfs2_is_empty_extent(&(path_leaf_el(path)->l_recs[0]))) + return 0; *empty_extent_path = NULL; |