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| author | Qu Wenruo <wqu@suse.com> | 2020-07-14 03:12:20 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2020-07-27 12:55:44 +0200 |
| commit | a3cf0e4342b6af9e6b34a4b913c630fbd03a82ea (patch) | |
| tree | fa61bb56b994d99516f9c8430ad61a8bd235aa2e | |
| parent | btrfs: ref-verify: fix memory leak in add_block_entry (diff) | |
| download | linux-a3cf0e4342b6af9e6b34a4b913c630fbd03a82ea.tar.xz linux-a3cf0e4342b6af9e6b34a4b913c630fbd03a82ea.zip | |
btrfs: qgroup: free per-trans reserved space when a subvolume gets dropped
[BUG]
Sometime fsstress could lead to qgroup warning for case like
generic/013:
BTRFS warning (device dm-3): qgroup 0/259 has unreleased space, type 1 rsv 81920
------------[ cut here ]------------
WARNING: CPU: 9 PID: 24535 at fs/btrfs/disk-io.c:4142 close_ctree+0x1dc/0x323 [btrfs]
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010: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 6c341cdf9b6cc3c1 ]---
BTRFS error (device dm-3): qgroup reserved space leaked
While that subvolume 259 is no longer in that filesystem.
[CAUSE]
Normally per-trans qgroup reserved space is freed when a transaction is
committed, in commit_fs_roots().
However for completely dropped subvolume, that subvolume is completely
gone, thus is no longer in the fs_roots_radix, and its per-trans
reserved qgroup will never be freed.
Since the subvolume is already gone, leaked per-trans space won't cause
any trouble for end users.
[FIX]
Just call btrfs_qgroup_free_meta_all_pertrans() before a subvolume is
completely dropped.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
| -rw-r--r-- | fs/btrfs/extent-tree.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index c0bc35f932bf..96223813b618 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -5466,6 +5466,14 @@ int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc) } } + /* + * This subvolume is going to be completely dropped, and won't be + * recorded as dirty roots, thus pertrans meta rsv will not be freed at + * commit transaction time. So free it here manually. + */ + btrfs_qgroup_convert_reserved_meta(root, INT_MAX); + btrfs_qgroup_free_meta_all_pertrans(root); + if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) btrfs_add_dropped_root(trans, root); else |