btrfs: factor __btrfs_open_devices() to create btrfs_open_one_device()

No functional changes, create btrfs_open_one_device() from
__btrfs_open_devices(). This is a preparatory work to add dynamic
device scan.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
[ minor whitespace fixes ]
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 04d2052..20039d6 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -659,6 +659,70 @@ static void btrfs_free_stale_device(struct btrfs_device *cur_dev)
        }
 }
 
+static int btrfs_open_one_device(struct btrfs_fs_devices *fs_devices,
+                       struct btrfs_device *device, fmode_t flags,
+                       void *holder)
+{
+       struct request_queue *q;
+       struct block_device *bdev;
+       struct buffer_head *bh;
+       struct btrfs_super_block *disk_super;
+       u64 devid;
+       int ret;
+
+       if (device->bdev)
+               return -EINVAL;
+       if (!device->name)
+               return -EINVAL;
+
+       ret = btrfs_get_bdev_and_sb(device->name->str, flags, holder, 1,
+                                   &bdev, &bh);
+       if (ret)
+               return ret;
+
+       disk_super = (struct btrfs_super_block *)bh->b_data;
+       devid = btrfs_stack_device_id(&disk_super->dev_item);
+       if (devid != device->devid)
+               goto error_brelse;
+
+       if (memcmp(device->uuid, disk_super->dev_item.uuid, BTRFS_UUID_SIZE))
+               goto error_brelse;
+
+       device->generation = btrfs_super_generation(disk_super);
+
+       if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
+               device->writeable = 0;
+               fs_devices->seeding = 1;
+       } else {
+               device->writeable = !bdev_read_only(bdev);
+       }
+
+       q = bdev_get_queue(bdev);
+       if (blk_queue_discard(q))
+               device->can_discard = 1;
+       if (!blk_queue_nonrot(q))
+               fs_devices->rotating = 1;
+
+       device->bdev = bdev;
+       device->in_fs_metadata = 0;
+       device->mode = flags;
+
+       fs_devices->open_devices++;
+       if (device->writeable && device->devid != BTRFS_DEV_REPLACE_DEVID) {
+               fs_devices->rw_devices++;
+               list_add(&device->dev_alloc_list, &fs_devices->alloc_list);
+       }
+       brelse(bh);
+
+       return 0;
+
+error_brelse:
+       brelse(bh);
+       blkdev_put(bdev, flags);
+
+       return -EINVAL;
+}
+
 /*
  * Add new device to list of registered devices
  *
@@ -1011,76 +1075,21 @@ int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
                                fmode_t flags, void *holder)
 {
-       struct request_queue *q;
-       struct block_device *bdev;
        struct list_head *head = &fs_devices->devices;
        struct btrfs_device *device;
        struct btrfs_device *latest_dev = NULL;
-       struct buffer_head *bh;
-       struct btrfs_super_block *disk_super;
-       u64 devid;
        int ret = 0;
 
        flags |= FMODE_EXCL;
 
        list_for_each_entry(device, head, dev_list) {
-               if (device->bdev)
-                       continue;
-               if (!device->name)
-                       continue;
-
                /* Just open everything we can; ignore failures here */
-               if (btrfs_get_bdev_and_sb(device->name->str, flags, holder, 1,
-                                           &bdev, &bh))
+               if (btrfs_open_one_device(fs_devices, device, flags, holder))
                        continue;
 
-               disk_super = (struct btrfs_super_block *)bh->b_data;
-               devid = btrfs_stack_device_id(&disk_super->dev_item);
-               if (devid != device->devid)
-                       goto error_brelse;
-
-               if (memcmp(device->uuid, disk_super->dev_item.uuid,
-                          BTRFS_UUID_SIZE))
-                       goto error_brelse;
-
-               device->generation = btrfs_super_generation(disk_super);
-
-               if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
-                       device->writeable = 0;
-                       fs_devices->seeding = 1;
-               } else {
-                       device->writeable = !bdev_read_only(bdev);
-               }
-
-               q = bdev_get_queue(bdev);
-               if (blk_queue_discard(q))
-                       device->can_discard = 1;
-               if (!blk_queue_nonrot(q))
-                       fs_devices->rotating = 1;
-
-               device->bdev = bdev;
-               device->in_fs_metadata = 0;
-               device->mode = flags;
-
-               fs_devices->open_devices++;
-               if (device->writeable &&
-                   device->devid != BTRFS_DEV_REPLACE_DEVID) {
-                       fs_devices->rw_devices++;
-                       list_add(&device->dev_alloc_list,
-                                &fs_devices->alloc_list);
-               }
-               brelse(bh);
-
                if (!latest_dev ||
                    device->generation > latest_dev->generation)
                        latest_dev = device;
-
-               continue;
-
-error_brelse:
-               brelse(bh);
-               blkdev_put(bdev, flags);
-               continue;
        }
        if (fs_devices->open_devices == 0) {
                ret = -EINVAL;