From mboxrd@z Thu Jan 1 00:00:00 1970 From: Miao Xie Subject: [PATCH] btrfs: fix possible deadlock by clearing __GFP_FS flag Date: Sun, 27 Mar 2011 16:07:36 +0800 Message-ID: <4D8EF048.5050203@cn.fujitsu.com> Reply-To: miaox@cn.fujitsu.com Mime-Version: 1.0 Content-Type: text/plain; charset=GB2312 Cc: Linux Btrfs To: Chris Mason , Itaru Kitayama Return-path: List-ID: Using the GFP_HIGHUSER_MOVABLE flag to allocate the metadata's page may cause deadlock. Task1 Kswap0 task open() ... btrfs_search_slot() ... btrfs_cow_block() ... alloc_page() wait for reclaiming shrink_slab() ... shrink_icache_memory() ... btrfs_evict_inode() ... btrfs_search_slot() If the path is locked by task1, the deadlock happens. So the btree's page cache is different with the file's page cache, it can not allocate pages by GFP_HIGHUSER_MOVABLE flag, we must clear __GFP_FS flag in GFP_HIGHUSER_MOVABLE flag. Reported-by: Itaru Kitayama Signed-off-by: Miao Xie --- fs/btrfs/disk-io.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 3e1ea3e..cf55fa0 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1632,6 +1632,8 @@ struct btrfs_root *open_ctree(struct super_block *sb, goto fail_bdi; } + fs_info->btree_inode->i_mapping->flags &= ~__GFP_FS; + INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC); INIT_LIST_HEAD(&fs_info->trans_list); INIT_LIST_HEAD(&fs_info->dead_roots); -- 1.7.4