btrfs: fix oops when doing space balance
We need to make sure the data relocation inode doesn't go through
the delayed metadata updates, otherwise we get an oops during balance:
kernel BUG at fs/btrfs/relocation.c:4303!
[SNIP]
Call Trace:
[<ffffffffa03143fd>] ? update_ref_for_cow+0x22d/0x330 [btrfs]
[<ffffffffa0314951>] __btrfs_cow_block+0x451/0x5e0 [btrfs]
[<ffffffffa031355d>] ? read_block_for_search+0x14d/0x4d0 [btrfs]
[<ffffffffa0314beb>] btrfs_cow_block+0x10b/0x240 [btrfs]
[<ffffffffa031acae>] btrfs_search_slot+0x49e/0x7a0 [btrfs]
[<ffffffffa032d8af>] btrfs_lookup_inode+0x2f/0xa0 [btrfs]
[<ffffffff8147bf0e>] ? mutex_lock+0x1e/0x50
[<ffffffffa0380cf1>] btrfs_update_delayed_inode+0x71/0x160 [btrfs]
[<ffffffffa037ff27>] ? __btrfs_release_delayed_node+0x67/0x190 [btrfs]
[<ffffffffa0381cf8>] btrfs_run_delayed_items+0xe8/0x120 [btrfs]
[<ffffffffa03365e0>] btrfs_commit_transaction+0x250/0x850 [btrfs]
[<ffffffff810f91d9>] ? find_get_pages+0x39/0x130
[<ffffffffa0336cd5>] ? join_transaction+0x25/0x250 [btrfs]
[<ffffffff81081de0>] ? wake_up_bit+0x40/0x40
[<ffffffffa03785fa>] prepare_to_relocate+0xda/0xf0 [btrfs]
[<ffffffffa037f2bb>] relocate_block_group+0x4b/0x620 [btrfs]
[<ffffffffa0334cf5>] ? btrfs_clean_old_snapshots+0x35/0x150 [btrfs]
[<ffffffffa037fa43>] btrfs_relocate_block_group+0x1b3/0x2e0 [btrfs]
[<ffffffffa0368ec0>] ? btrfs_tree_unlock+0x50/0x50 [btrfs]
[<ffffffffa035e39b>] btrfs_relocate_chunk+0x8b/0x670 [btrfs]
[<ffffffffa031303d>] ? btrfs_set_path_blocking+0x3d/0x50 [btrfs]
[<ffffffffa03577d8>] ? read_extent_buffer+0xd8/0x1d0 [btrfs]
[<ffffffffa031bea1>] ? btrfs_previous_item+0xb1/0x150 [btrfs]
[<ffffffffa03577d8>] ? read_extent_buffer+0xd8/0x1d0 [btrfs]
[<ffffffffa035f5aa>] btrfs_balance+0x21a/0x2b0 [btrfs]
[<ffffffffa0368898>] btrfs_ioctl+0x798/0xd20 [btrfs]
[<ffffffff8111e358>] ? handle_mm_fault+0x148/0x270
[<ffffffff814809e8>] ? do_page_fault+0x1d8/0x4b0
[<ffffffff81160d6a>] do_vfs_ioctl+0x9a/0x540
[<ffffffff811612b1>] sys_ioctl+0xa1/0xb0
[<ffffffff81484ec2>] system_call_fastpath+0x16/0x1b
[SNIP]
RIP [<ffffffffa037c1cc>] btrfs_reloc_cow_block+0x22c/0x270 [btrfs]
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 447612d..4a13730 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2678,12 +2678,14 @@
int ret;
/*
- * If root is tree root, it means this inode is used to
- * store free space information. And these inodes are updated
- * when committing the transaction, so they needn't delaye to
- * be updated, or deadlock will occured.
+ * If the inode is a free space inode, we can deadlock during commit
+ * if we put it into the delayed code.
+ *
+ * The data relocation inode should also be directly updated
+ * without delay
*/
- if (!is_free_space_inode(root, inode)) {
+ if (!is_free_space_inode(root, inode)
+ && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID) {
ret = btrfs_delayed_update_inode(trans, root, inode);
if (!ret)
btrfs_set_inode_last_trans(trans, inode);