[PATCH 1/6] btrfs: do btrfs_free_stale_devices() outside of device_list_add()

[Anand Jain]

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

In preparation to handle proper locks in the device_list_add(),
move the btrfs_free_stale_devices() outside of the device_list_add()
as these two functions has two distinct purpose.

Signed-off-by: Anand Jain <anand.j...@oracle.com>
---
 fs/btrfs/volumes.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 0a47b4162d12..4edba7c5c050 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -750,7 +750,8 @@ static int btrfs_open_one_device(struct btrfs_fs_devices 
*fs_devices,
  * 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;
@@ -796,7 +797,7 @@ 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",
@@ -1223,6 +1224,7 @@ 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;
@@ -1248,11 +1250,14 @@ 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);
-- 
2.7.0

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