From e85fde5162bf1b242cbd6daf7dba0f9b457d592b Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Fri, 24 Jul 2020 14:46:10 +0800 Subject: btrfs: qgroup: fix qgroup meta rsv leak for subvolume operations [BUG] When quota is enabled for TEST_DEV, generic/013 sometimes fails like this: generic/013 14s ... _check_dmesg: something found in dmesg (see xfstests-dev/results//generic/013.dmesg) And with the following metadata leak: BTRFS warning (device dm-3): qgroup 0/1370 has unreleased space, type 2 rsv 49152 ------------[ cut here ]------------ WARNING: CPU: 2 PID: 47912 at fs/btrfs/disk-io.c:4078 close_ctree+0x1dc/0x323 [btrfs] Call Trace: btrfs_put_super+0x15/0x17 [btrfs] generic_shutdown_super+0x72/0x110 kill_anon_super+0x18/0x30 btrfs_kill_super+0x17/0x30 [btrfs] deactivate_locked_super+0x3b/0xa0 deactivate_super+0x40/0x50 cleanup_mnt+0x135/0x190 __cleanup_mnt+0x12/0x20 task_work_run+0x64/0xb0 __prepare_exit_to_usermode+0x1bc/0x1c0 __syscall_return_slowpath+0x47/0x230 do_syscall_64+0x64/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 ---[ end trace a6cfd45ba80e4e06 ]--- BTRFS error (device dm-3): qgroup reserved space leaked BTRFS info (device dm-3): disk space caching is enabled BTRFS info (device dm-3): has skinny extents [CAUSE] The qgroup preallocated meta rsv operations of that offending root are: btrfs_delayed_inode_reserve_metadata: rsv_meta_prealloc root=1370 num_bytes=131072 btrfs_delayed_inode_reserve_metadata: rsv_meta_prealloc root=1370 num_bytes=131072 btrfs_subvolume_reserve_metadata: rsv_meta_prealloc root=1370 num_bytes=49152 btrfs_delayed_inode_release_metadata: convert_meta_prealloc root=1370 num_bytes=-131072 btrfs_delayed_inode_release_metadata: convert_meta_prealloc root=1370 num_bytes=-131072 It's pretty obvious that, we reserve qgroup meta rsv in btrfs_subvolume_reserve_metadata(), but doesn't have corresponding release/convert calls in btrfs_subvolume_release_metadata(). This leads to the leakage. [FIX] To fix this bug, we should follow what we're doing in btrfs_delalloc_reserve_metadata(), where we reserve qgroup space, and add it to block_rsv->qgroup_rsv_reserved. And free the qgroup reserved metadata space when releasing the block_rsv. To do this, we need to change the btrfs_subvolume_release_metadata() to accept btrfs_root, and record the qgroup_to_release number, and call btrfs_qgroup_convert_reserved_meta() for it. Fixes: 733e03a0b26a ("btrfs: qgroup: Split meta rsv type into meta_prealloc and meta_pertrans") CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Josef Bacik Signed-off-by: Qu Wenruo Signed-off-by: David Sterba --- fs/btrfs/root-tree.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'fs/btrfs/root-tree.c') diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c index c89697486366..702dc5441f03 100644 --- a/fs/btrfs/root-tree.c +++ b/fs/btrfs/root-tree.c @@ -512,11 +512,20 @@ int btrfs_subvolume_reserve_metadata(struct btrfs_root *root, if (ret && qgroup_num_bytes) btrfs_qgroup_free_meta_prealloc(root, qgroup_num_bytes); + if (!ret) { + spin_lock(&rsv->lock); + rsv->qgroup_rsv_reserved += qgroup_num_bytes; + spin_unlock(&rsv->lock); + } return ret; } -void btrfs_subvolume_release_metadata(struct btrfs_fs_info *fs_info, +void btrfs_subvolume_release_metadata(struct btrfs_root *root, struct btrfs_block_rsv *rsv) { - btrfs_block_rsv_release(fs_info, rsv, (u64)-1, NULL); + struct btrfs_fs_info *fs_info = root->fs_info; + u64 qgroup_to_release; + + btrfs_block_rsv_release(fs_info, rsv, (u64)-1, &qgroup_to_release); + btrfs_qgroup_convert_reserved_meta(root, qgroup_to_release); } -- cgit v1.2.3