From: Jaegeuk Kim Date: Tue, 1 Dec 2015 00:26:44 +0000 (-0800) Subject: f2fs: avoid deadlock in f2fs_shrink_extent_tree X-Git-Url: http://git.efficios.com/?a=commitdiff_plain;h=760de7914e27781abb44564449c761ea4440f982;p=deliverable%2Flinux.git f2fs: avoid deadlock in f2fs_shrink_extent_tree While handling extent trees, we can enter into a reclaiming path anytime. If it tries to release some extent nodes in the same extent tree, write_lock(&et->lock) would be hanged. In order to avoid the deadlock, we can just skip it. Note that, if it is an unreferenced tree, we should get write_lock(&et->lock) successfully and release all of therein nodes. Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim --- diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c index 7ddba812e11b..de063f2b2384 100644 --- a/fs/f2fs/extent_cache.c +++ b/fs/f2fs/extent_cache.c @@ -615,9 +615,10 @@ unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink) for (i = 0; i < found; i++) { struct extent_tree *et = treevec[i]; - write_lock(&et->lock); - node_cnt += __free_extent_tree(sbi, et, false); - write_unlock(&et->lock); + if (write_trylock(&et->lock)) { + node_cnt += __free_extent_tree(sbi, et, false); + write_unlock(&et->lock); + } if (node_cnt + tree_cnt >= nr_shrink) goto unlock_out;