Btrfs: move some common code into a subfunction

Some code to open block devices, to read the superblock and to
handle errors was repeated multiple times in 3 places, and the
following patch makes use of it as well. This code is now moved
into a subfunction.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 92e586b..4def1fd 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -108,6 +108,44 @@ static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
        return NULL;
 }
 
+static int
+btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder,
+                     int flush, struct block_device **bdev,
+                     struct buffer_head **bh)
+{
+       int ret;
+
+       *bdev = blkdev_get_by_path(device_path, flags, holder);
+
+       if (IS_ERR(*bdev)) {
+               ret = PTR_ERR(*bdev);
+               printk(KERN_INFO "btrfs: open %s failed\n", device_path);
+               goto error;
+       }
+
+       if (flush)
+               filemap_write_and_wait((*bdev)->bd_inode->i_mapping);
+       ret = set_blocksize(*bdev, 4096);
+       if (ret) {
+               blkdev_put(*bdev, flags);
+               goto error;
+       }
+       invalidate_bdev(*bdev);
+       *bh = btrfs_read_dev_super(*bdev);
+       if (!*bh) {
+               ret = -EINVAL;
+               blkdev_put(*bdev, flags);
+               goto error;
+       }
+
+       return 0;
+
+error:
+       *bdev = NULL;
+       *bh = NULL;
+       return ret;
+}
+
 static void requeue_list(struct btrfs_pending_bios *pending_bios,
                        struct bio *head, struct bio *tail)
 {
@@ -637,18 +675,10 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
                if (!device->name)
                        continue;
 
-               bdev = blkdev_get_by_path(device->name->str, flags, holder);
-               if (IS_ERR(bdev)) {
-                       printk(KERN_INFO "btrfs: open %s failed\n", device->name->str);
-                       goto error;
-               }
-               filemap_write_and_wait(bdev->bd_inode->i_mapping);
-               invalidate_bdev(bdev);
-               set_blocksize(bdev, 4096);
-
-               bh = btrfs_read_dev_super(bdev);
-               if (!bh)
-                       goto error_close;
+               ret = btrfs_get_bdev_and_sb(device->name->str, flags, holder, 1,
+                                           &bdev, &bh);
+               if (ret)
+                       continue;
 
                disk_super = (struct btrfs_super_block *)bh->b_data;
                devid = btrfs_stack_device_id(&disk_super->dev_item);
@@ -697,9 +727,7 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 
 error_brelse:
                brelse(bh);
-error_close:
                blkdev_put(bdev, flags);
-error:
                continue;
        }
        if (fs_devices->open_devices == 0) {
@@ -744,22 +772,10 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
        u64 total_devices;
 
        flags |= FMODE_EXCL;
-       bdev = blkdev_get_by_path(path, flags, holder);
-
-       if (IS_ERR(bdev)) {
-               ret = PTR_ERR(bdev);
-               goto error;
-       }
-
        mutex_lock(&uuid_mutex);
-       ret = set_blocksize(bdev, 4096);
+       ret = btrfs_get_bdev_and_sb(path, flags, holder, 0, &bdev, &bh);
        if (ret)
-               goto error_close;
-       bh = btrfs_read_dev_super(bdev);
-       if (!bh) {
-               ret = -EINVAL;
-               goto error_close;
-       }
+               goto error;
        disk_super = (struct btrfs_super_block *)bh->b_data;
        devid = btrfs_stack_device_id(&disk_super->dev_item);
        transid = btrfs_super_generation(disk_super);
@@ -777,10 +793,9 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
        if (!ret && fs_devices_ret)
                (*fs_devices_ret)->total_devices = total_devices;
        brelse(bh);
-error_close:
-       mutex_unlock(&uuid_mutex);
        blkdev_put(bdev, flags);
 error:
+       mutex_unlock(&uuid_mutex);
        return ret;
 }
 
@@ -1374,20 +1389,12 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
                        goto out;
                }
        } else {
-               bdev = blkdev_get_by_path(device_path, FMODE_READ | FMODE_EXCL,
-                                         root->fs_info->bdev_holder);
-               if (IS_ERR(bdev)) {
-                       ret = PTR_ERR(bdev);
+               ret = btrfs_get_bdev_and_sb(device_path,
+                                           FMODE_READ | FMODE_EXCL,
+                                           root->fs_info->bdev_holder, 0,
+                                           &bdev, &bh);
+               if (ret)
                        goto out;
-               }
-
-               set_blocksize(bdev, 4096);
-               invalidate_bdev(bdev);
-               bh = btrfs_read_dev_super(bdev);
-               if (!bh) {
-                       ret = -EINVAL;
-                       goto error_close;
-               }
                disk_super = (struct btrfs_super_block *)bh->b_data;
                devid = btrfs_stack_device_id(&disk_super->dev_item);
                dev_uuid = disk_super->dev_item.uuid;