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authorFilipe Manana <fdmanana@suse.com>2020-11-23 21:30:54 +0300
committerDavid Sterba <dsterba@suse.com>2020-11-23 23:16:40 +0300
commit7aa6d359845a9dbf7ad90b0b1b6347ef4764621f (patch)
treee34bbb885dfb58867e84da5e6ba1171660b250b7 /fs/btrfs/qgroup.c
parent3d05cad3c357a2b749912914356072b38435edfa (diff)
downloadlinux-7aa6d359845a9dbf7ad90b0b1b6347ef4764621f.tar.xz
btrfs: do nofs allocations when adding and removing qgroup relations
When adding or removing a qgroup relation we are doing a GFP_KERNEL allocation which is not safe because we are holding a transaction handle open and that can make us deadlock if the allocator needs to recurse into the filesystem. So just surround those calls with a nofs context. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/qgroup.c')
-rw-r--r--fs/btrfs/qgroup.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index a3f0d209fce5..d690ef702522 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -11,6 +11,7 @@
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/btrfs.h>
+#include <linux/sched/mm.h>
#include "ctree.h"
#include "transaction.h"
@@ -1324,13 +1325,17 @@ int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
struct btrfs_qgroup *member;
struct btrfs_qgroup_list *list;
struct ulist *tmp;
+ unsigned int nofs_flag;
int ret = 0;
/* Check the level of src and dst first */
if (btrfs_qgroup_level(src) >= btrfs_qgroup_level(dst))
return -EINVAL;
+ /* We hold a transaction handle open, must do a NOFS allocation. */
+ nofs_flag = memalloc_nofs_save();
tmp = ulist_alloc(GFP_KERNEL);
+ memalloc_nofs_restore(nofs_flag);
if (!tmp)
return -ENOMEM;
@@ -1387,10 +1392,14 @@ static int __del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
struct btrfs_qgroup_list *list;
struct ulist *tmp;
bool found = false;
+ unsigned int nofs_flag;
int ret = 0;
int ret2;
+ /* We hold a transaction handle open, must do a NOFS allocation. */
+ nofs_flag = memalloc_nofs_save();
tmp = ulist_alloc(GFP_KERNEL);
+ memalloc_nofs_restore(nofs_flag);
if (!tmp)
return -ENOMEM;