btrfs: factor out scratching of one regular super block

btrfs_scratch_superblocks open codes scratching super block of a
non-zoned super block.  Split the code to read, zero and write the
superblock for regular devices into a separate helper.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index bf0decaac7f3020e2081b471575a242a91bbf4ad..119dc26ca141cde4fc7d3bd6d3681a3a059f8171 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2014,42 +2014,43 @@ static u64 btrfs_num_devices(struct btrfs_fs_info *fs_info)
        return num_devices;
 }
 
+static void btrfs_scratch_superblock(struct btrfs_fs_info *fs_info,
+                                    struct block_device *bdev, int copy_num)
+{
+       struct btrfs_super_block *disk_super;
+       struct page *page;
+       int ret;
+
+       disk_super = btrfs_read_dev_one_super(bdev, copy_num, false);
+       if (IS_ERR(disk_super))
+               return;
+
+       memset(&disk_super->magic, 0, sizeof(disk_super->magic));
+       page = virt_to_page(disk_super);
+       set_page_dirty(page);
+       lock_page(page);
+       /* write_on_page() unlocks the page */
+       ret = write_one_page(page);
+       if (ret)
+               btrfs_warn(fs_info, "error clearing superblock number %d (%d)",
+                       copy_num, ret);
+       btrfs_release_disk_super(disk_super);
+}
+
 void btrfs_scratch_superblocks(struct btrfs_fs_info *fs_info,
                               struct block_device *bdev,
                               const char *device_path)
 {
-       struct btrfs_super_block *disk_super;
        int copy_num;
 
        if (!bdev)
                return;
 
        for (copy_num = 0; copy_num < BTRFS_SUPER_MIRROR_MAX; copy_num++) {
-               struct page *page;
-               int ret;
-
-               disk_super = btrfs_read_dev_one_super(bdev, copy_num, false);
-               if (IS_ERR(disk_super))
-                       continue;
-
-               if (bdev_is_zoned(bdev)) {
+               if (bdev_is_zoned(bdev))
                        btrfs_reset_sb_log_zones(bdev, copy_num);
-                       continue;
-               }
-
-               memset(&disk_super->magic, 0, sizeof(disk_super->magic));
-
-               page = virt_to_page(disk_super);
-               set_page_dirty(page);
-               lock_page(page);
-               /* write_on_page() unlocks the page */
-               ret = write_one_page(page);
-               if (ret)
-                       btrfs_warn(fs_info,
-                               "error clearing superblock number %d (%d)",
-                               copy_num, ret);
-               btrfs_release_disk_super(disk_super);
-
+               else
+                       btrfs_scratch_superblock(fs_info, bdev, copy_num);
        }
 
        /* Notify udev that device has changed */