btrfs-progs: use on-stack buffer for superblock

In update_disk_super_on_device,the buffer size is small, allocate it
onstack and get rid of one error path.

Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/btrfs-image.c b/btrfs-image.c
index 18ad398..630fdf8 100644 (file)
--- a/btrfs-image.c
+++ b/btrfs-image.c
@@ -2588,7 +2588,7 @@ static int update_disk_super_on_device(struct btrfs_fs_info *info,
        char fs_uuid[BTRFS_UUID_SIZE];
        u64 devid, type, io_align, io_width;
        u64 sector_size, total_bytes, bytes_used;
-       char *buf = NULL;
+       char buf[BTRFS_SUPER_INFO_SIZE];
        int fp = -1;
        int ret;
 
@@ -2636,13 +2636,6 @@ static int update_disk_super_on_device(struct btrfs_fs_info *info,
                goto out;
        }
 
-       buf = malloc(BTRFS_SUPER_INFO_SIZE);
-       if (!buf) {
-               ret = -ENOMEM;
-               close(fp);
-               return ret;
-       }
-
        memcpy(buf, info->super_copy, BTRFS_SUPER_INFO_SIZE);
 
        disk_super = (struct btrfs_super_block *)buf;
@@ -2672,7 +2665,6 @@ static int update_disk_super_on_device(struct btrfs_fs_info *info,
        write_backup_supers(fp, (u8 *)buf);
 
 out:
-       free(buf);
        if (fp != -1)
                close(fp);
        return ret;