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Commit 967ef513 authored by Justin Maggard's avatar Justin Maggard Committed by Chris Mason
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btrfs: qgroup: fix quota disable during rescan 



There's a race condition that leads to a NULL pointer dereference if you
disable quotas while a quota rescan is running.  To fix this, we just need
to wait for the quota rescan worker to actually exit before tearing down
the quota structures.

Signed-off-by: default avatarJustin Maggard <jmaggard@netgear.com>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent 036a9348

fs/btrfs/qgroup.c

+2 −1
Original line number Diff line number Diff line
@@ -993,9 +993,10 @@ int btrfs_quota_disable(struct btrfs_trans_handle *trans, 
	mutex_lock(&fs_info->qgroup_ioctl_lock);

	if (!fs_info->quota_root)

		goto out;

	spin_lock(&fs_info->qgroup_lock);

	fs_info->quota_enabled = 0;

	fs_info->pending_quota_state = 0;

	btrfs_qgroup_wait_for_completion(fs_info);

	spin_lock(&fs_info->qgroup_lock);

	quota_root = fs_info->quota_root;

	fs_info->quota_root = NULL;

	fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_ON;