The allocation happens with GFP_KERNEL after a transaction has been
started, this can potentially cause deadlock if reclaim tries to get the
memory by flushing filesystem data.
The qgroup_ulist is not used during transaction start as the quotas are
not yet enabled but to provide the same semantics, use a temporary
variable and assign fs_info::qgroup_ulist as before.
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
---
fs/btrfs/qgroup.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index c1cd5558a646..9e49d5e132b8 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -887,6 +887,7 @@ int btrfs_quota_enable(struct btrfs_fs_info *fs_info)
struct btrfs_key found_key;
struct btrfs_qgroup *qgroup = NULL;
struct btrfs_trans_handle *trans = NULL;
+ struct ulist *tmp_ulist;
int ret = 0;
int slot;
@@ -894,6 +895,12 @@ int btrfs_quota_enable(struct btrfs_fs_info *fs_info)
if (fs_info->quota_root)
goto out;
+ tmp_ulist = ulist_alloc(GFP_KERNEL);
+ if (!tmp_ulist) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
/*
* 1 for quota root item
* 1 for BTRFS_QGROUP_STATUS item
@@ -909,12 +916,7 @@ int btrfs_quota_enable(struct btrfs_fs_info *fs_info)
goto out;
}
- fs_info->qgroup_ulist = ulist_alloc(GFP_KERNEL);
- if (!fs_info->qgroup_ulist) {
- ret = -ENOMEM;
- btrfs_abort_transaction(trans, ret);
- goto out;
- }
+ fs_info->qgroup_ulist = tmp_ulist;
/*
* initially create the quota tree
--
2.20.1
