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authorMiao Xie <miaox@cn.fujitsu.com>2011-03-27 16:07:36 +0800
committerroot <Chris Mason chris.mason@oracle.com>2011-03-28 05:37:58 -0400
commit1561deda687eef0e95065f1268d680ddc5976ee7 (patch)
tree3ad8a8305fc3ca960cf7ef472f64d9cfef246ffd
parentc055e99eea6e4f614267632fac546e7896c0227b (diff)
btrfs: fix possible deadlock by clearing __GFP_FS flag
Using the GFP_HIGHUSER_MOVABLE flag to allocate the metadata's page may cause deadlock. Task1 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 <kitayama@cl.bb4u.ne.jp> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
-rw-r--r--fs/btrfs/disk-io.c2
-rw-r--r--fs/btrfs/inode.c3
2 files changed, 4 insertions, 1 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index b3fc8475870f..5cf3aa7b125c 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1724,6 +1724,8 @@ 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);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 04babaf31a33..06274186b290 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2536,6 +2536,8 @@ static void btrfs_read_locked_inode(struct inode *inode)
BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
alloc_group_block = btrfs_inode_block_group(leaf, inode_item);
+ if (location.objectid == BTRFS_FREE_SPACE_OBJECTID)
+ inode->i_mapping->flags &= ~__GFP_FS;
/*
* try to precache a NULL acl entry for files that don't have
@@ -4084,7 +4086,6 @@ struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
BTRFS_I(inode)->root = root;
memcpy(&BTRFS_I(inode)->location, location, sizeof(*location));
btrfs_read_locked_inode(inode);
-
inode_tree_add(inode);
unlock_new_inode(inode);
if (new)