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authorJosef Bacik <josef@toxicpanda.com>2018-09-28 07:17:49 -0400
committerDavid Sterba <dsterba@suse.com>2018-10-15 17:23:38 +0200
commit84de76a2fb217dc1b6bc2965cc397d1648aa1404 (patch)
tree03c0908b3ed542b43d9d57bf0a5a41db70461403 /fs/btrfs
parentf45c752b65af46bf42963295c332865d95f97fff (diff)
downloadlinux-84de76a2fb217dc1b6bc2965cc397d1648aa1404.tar.bz2
btrfs: protect space cache inode alloc with GFP_NOFS
If we're allocating a new space cache inode it's likely going to be under a transaction handle, so we need to use memalloc_nofs_save() in order to avoid deadlocks, and more importantly lockdep messages that make xfstests fail. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/free-space-cache.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index ed097ff023e8..a1f379e8ad13 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -10,6 +10,7 @@
#include <linux/math64.h>
#include <linux/ratelimit.h>
#include <linux/error-injection.h>
+#include <linux/sched/mm.h>
#include "ctree.h"
#include "free-space-cache.h"
#include "transaction.h"
@@ -47,6 +48,7 @@ static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
struct btrfs_free_space_header *header;
struct extent_buffer *leaf;
struct inode *inode = NULL;
+ unsigned nofs_flag;
int ret;
key.objectid = BTRFS_FREE_SPACE_OBJECTID;
@@ -68,7 +70,13 @@ static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
btrfs_disk_key_to_cpu(&location, &disk_key);
btrfs_release_path(path);
+ /*
+ * We are often under a trans handle at this point, so we need to make
+ * sure NOFS is set to keep us from deadlocking.
+ */
+ nofs_flag = memalloc_nofs_save();
inode = btrfs_iget(fs_info->sb, &location, root, NULL);
+ memalloc_nofs_restore(nofs_flag);
if (IS_ERR(inode))
return inode;