btrfs: do btrfs_free_stale_devices outside of device_list_add

btrfs_free_stale_devices() looks for device path reused for another
filesystem, and deletes the older fs_devices::device entry.

In preparation to handle locking in device_list_add, move
btrfs_free_stale_devices outside as these two functions serve a
different purpose.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 3c3359d..c84a9e2 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -747,7 +747,8 @@ error_brelse:
  * error pointer when failed
  */
 static noinline struct btrfs_device *device_list_add(const char *path,
-                          struct btrfs_super_block *disk_super)
+                          struct btrfs_super_block *disk_super,
+                          bool *new_device_added)
 {
        struct btrfs_device *device;
        struct btrfs_fs_devices *fs_devices;
@@ -793,7 +794,7 @@ static noinline struct btrfs_device *device_list_add(const char *path,
                mutex_unlock(&fs_devices->device_list_mutex);
 
                device->fs_devices = fs_devices;
-               btrfs_free_stale_devices(path, device);
+               *new_device_added = true;
 
                if (disk_super->label[0])
                        pr_info("BTRFS: device label %s devid %llu transid %llu %s\n",
@@ -1204,6 +1205,7 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
                          struct btrfs_fs_devices **fs_devices_ret)
 {
        struct btrfs_super_block *disk_super;
+       bool new_device_added = false;
        struct btrfs_device *device;
        struct block_device *bdev;
        struct page *page;
@@ -1229,11 +1231,14 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
        }
 
        mutex_lock(&uuid_mutex);
-       device = device_list_add(path, disk_super);
-       if (IS_ERR(device))
+       device = device_list_add(path, disk_super, &new_device_added);
+       if (IS_ERR(device)) {
                ret = PTR_ERR(device);
-       else
+       } else {
                *fs_devices_ret = device->fs_devices;
+               if (new_device_added)
+                       btrfs_free_stale_devices(path, device);
+       }
        mutex_unlock(&uuid_mutex);
 
        btrfs_release_disk_super(page);