On 06/21/2018 01:51 AM, David Sterba wrote:
Prepartory work to fix race between mount and device scan.
The callers will have to manage the critical section, eg. mount wants
to scan and then call btrfs_open_devices without the ioctl scan walking
in and modifying the fs devices in the meantime.
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Reviewed-by: Anand Jain <anand.jain@xxxxxxxxxx>
Thanks, Anand
---
fs/btrfs/super.c | 2 ++
fs/btrfs/volumes.c | 4 ++--
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 735402ed3154..ee82d02f5453 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1569,7 +1569,9 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
goto error_fs_info;
}
+ mutex_lock(&uuid_mutex);
error = btrfs_open_devices(fs_devices, mode, fs_type);
+ mutex_unlock(&uuid_mutex);
if (error)
goto error_fs_info;
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 958bfe1a725c..5336d9832ba4 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1145,7 +1145,8 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
{
int ret;
- mutex_lock(&uuid_mutex);
+ lockdep_assert_held(&uuid_mutex);
+
mutex_lock(&fs_devices->device_list_mutex);
if (fs_devices->opened) {
fs_devices->opened++;
@@ -1155,7 +1156,6 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
ret = open_fs_devices(fs_devices, flags, holder);
}
mutex_unlock(&fs_devices->device_list_mutex);
- mutex_unlock(&uuid_mutex);
return ret;
}
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
