On 16/5/20 1:40 am, David Sterba wrote:
On Thu, May 14, 2020 at 03:46:59AM +0800, Anand Jain wrote:
A full list of tests just started.
fs/btrfs/volumes.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 60ab41c12e50..ebc8565d0f73 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -984,7 +984,6 @@ static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
if (IS_ERR(fs_devices))
return fs_devices;
So now here's the device_list_mutex taken by a caller but inside
clone_fs_devices there's
fs_devices = alloc_fs_devices(orig->fsid, NULL);
just before this line and it does a GFP_KERNEL allocation.
Oh right the allocations. Its not just about the other locks
as I thought before.
There are two ways to fix.
Use GFP_NOFS
I am not yet sure if it not possible. There were some previous
work on the GFP flags. I need to review them. or,
Move the allocation outside the locks.
Looking into both of these choices.
Thanks, Anand
This could
deadlock through the allocator trying to flush data and then superblock
write locking the device_list_mutex again.
- mutex_lock(&orig->device_list_mutex);
fs_devices->total_devices = orig->total_devices;
list_for_each_entry(orig_dev, &orig->devices, dev_list) {
