Hi David, I think this patch is forgot for v4.8 merge windows.
Xfstest btrfs/022 is complaining about the problem if the patch is not applied.
Thanks, Qu At 06/28/2016 09:57 AM, Qu Wenruo wrote:
If one mount btrfs with enospc_debug mount option and hit qgroup limits in btrfs_check_data_free_space(), then at unmount time, kernel warning will be triggered alone with a data space info dump. ------ ------------[ cut here ]------------ WARNING: CPU: 0 PID: 3875 at fs/btrfs/extent-tree.c:9785 btrfs_free_block_groups+0x2b8/0x460 [btrfs] Modules linked in: btrfs ext4 jbd2 mbcache xor zlib_deflate raid6_pq xfs [last unloaded: btrfs] CPU: 0 PID: 3875 Comm: umount Tainted: G W 4.7.0-rc4+ #13 Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 0000000000000000 ffff8800230a7d00 ffffffff813b89e5 0000000000000000 0000000000000000 ffff8800230a7d40 ffffffff810c9b8b 00002639230a7d50 ffff88003d523a78 ffff88003d523b80 ffff88000d1c0000 ffff88000d1c00c8 Call Trace: [<ffffffff813b89e5>] dump_stack+0x67/0x92 [<ffffffff810c9b8b>] __warn+0xcb/0xf0 [<ffffffff810c9c7d>] warn_slowpath_null+0x1d/0x20 [<ffffffffa0367508>] btrfs_free_block_groups+0x2b8/0x460 [btrfs] [<ffffffffa03792e3>] close_ctree+0x173/0x350 [btrfs] [<ffffffffa0348f39>] btrfs_put_super+0x19/0x20 [btrfs] [<ffffffff812449aa>] generic_shutdown_super+0x6a/0xf0 [<ffffffff81244ca2>] kill_anon_super+0x12/0x20 [<ffffffffa0349728>] btrfs_kill_super+0x18/0x110 [btrfs] [<ffffffff81244f1e>] deactivate_locked_super+0x3e/0x70 [<ffffffff8124536c>] deactivate_super+0x5c/0x60 [<ffffffff812667ef>] cleanup_mnt+0x3f/0x90 [<ffffffff81266882>] __cleanup_mnt+0x12/0x20 [<ffffffff810ecbd1>] task_work_run+0x81/0xc0 [<ffffffff810022f3>] exit_to_usermode_loop+0xb3/0xc0 [<ffffffff81002dc0>] syscall_return_slowpath+0xb0/0xc0 [<ffffffff81885f73>] entry_SYSCALL_64_fastpath+0xa6/0xa8 ---[ end trace 99b9af8484495c66 ]--- BTRFS: space_info 1 has 8044544 free, is not full BTRFS: space_info total=8388608, used=344064, pinned=0, reserved=0, may_use=409600, readonly=0 ------ The problem is in btrfs_check_data_free_space(), we reserve data space first and then reserve qgroup space. However if qgroup reserve failed, we didn't cleanup reserved data space, which leads to the kernel warning. Fix it by freeing reserved data space when qgroup_reserve_data() fails. Signed-off-by: Qu Wenruo <[email protected]> --- fs/btrfs/extent-tree.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 29e5d00..e349da0 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -4265,6 +4265,9 @@ int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len) * range, but don't impact performance on quota disable case. */ ret = btrfs_qgroup_reserve_data(inode, start, len); + if (ret < 0) + /* Qgroup reserve failed, need to cleanup reserved data space */ + btrfs_free_reserved_data_space(inode, start, len); return ret; }
-- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
