From 3628b4ca64f24a4ec55055597d0cb1c814729f8b Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Tue, 9 Oct 2018 14:36:45 +0800 Subject: [PATCH] btrfs: qgroup: Avoid calling qgroup functions if qgroup is not enabled Some qgroup trace events like btrfs_qgroup_release_data() and btrfs_qgroup_free_delayed_ref() can still be triggered even if qgroup is not enabled. This is caused by the lack of qgroup status check before calling some qgroup functions. Thankfully the functions can handle quota disabled case well and just do nothing for qgroup disabled case. This patch will do earlier check before triggering related trace events. And for enabled <-> disabled race case: 1) For enabled->disabled case Disable will wipe out all qgroups data including reservation and excl/rfer. Even if we leak some reservation or numbers, it will still be cleared, so nothing will go wrong. 2) For disabled -> enabled case Current btrfs_qgroup_release_data() will use extent_io tree to ensure we won't underflow reservation. And for delayed_ref we use head->qgroup_reserved to record the reserved space, so in that case head->qgroup_reserved should be 0 and we won't underflow. CC: stable@vger.kernel.org # 4.14+ Reported-by: Chris Murphy Link: https://lore.kernel.org/linux-btrfs/CAJCQCtQau7DtuUUeycCkZ36qjbKuxNzsgqJ7+sJ6W0dK_NLE3w@mail.gmail.com/ Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/qgroup.c | 4 ++++ fs/btrfs/qgroup.h | 2 ++ 2 files changed, 6 insertions(+) diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index ac9690f36a94..27f517315388 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -3521,6 +3521,10 @@ static int __btrfs_qgroup_release_data(struct inode *inode, int trace_op = QGROUP_RELEASE; int ret; + if (!test_bit(BTRFS_FS_QUOTA_ENABLED, + &BTRFS_I(inode)->root->fs_info->flags)) + return 0; + /* In release case, we shouldn't have @reserved */ WARN_ON(!free && reserved); if (free && reserved) diff --git a/fs/btrfs/qgroup.h b/fs/btrfs/qgroup.h index 80ebeb3ab5ba..d8f78f5ab854 100644 --- a/fs/btrfs/qgroup.h +++ b/fs/btrfs/qgroup.h @@ -255,6 +255,8 @@ void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info, static inline void btrfs_qgroup_free_delayed_ref(struct btrfs_fs_info *fs_info, u64 ref_root, u64 num_bytes) { + if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) + return; trace_btrfs_qgroup_free_delayed_ref(fs_info, ref_root, num_bytes); btrfs_qgroup_free_refroot(fs_info, ref_root, num_bytes, BTRFS_QGROUP_RSV_DATA); -- 2.11.0