1 files changed, 61 insertions, 0 deletions

diff --git a/fs/ocfs2/buffer_head_io.c b/fs/ocfs2/buffer_head_io.c
index c9037414f4f6..31aa61dc777b 100644
--- a/fs/ocfs2/buffer_head_io.c
+++ b/fs/ocfs2/buffer_head_io.c
@@ -280,3 +280,64 @@ bail:
         mlog_exit(status);
         return status;
 }
+
+/* Check whether the blkno is the super block or one of the backups. */
+static void ocfs2_check_super_or_backup(struct super_block *sb,
+                                        sector_t blkno)
+{
+        int i;
+        u64 backup_blkno;
+
+        if (blkno == OCFS2_SUPER_BLOCK_BLKNO)
+                return;
+
+        for (i = 0; i < OCFS2_MAX_BACKUP_SUPERBLOCKS; i++) {
+                backup_blkno = ocfs2_backup_super_blkno(sb, i);
+                if (backup_blkno == blkno)
+                        return;
+        }
+
+        BUG();
+}
+
+/*
+ * Write super block and backups doesn't need to collaborate with journal,
+ * so we don't need to lock ip_io_mutex and inode doesn't need to bea passed
+ * into this function.
+ */
+int ocfs2_write_super_or_backup(struct ocfs2_super *osb,
+                                struct buffer_head *bh)
+{
+        int ret = 0;
+
+        mlog_entry_void();
+
+        BUG_ON(buffer_jbd(bh));
+        ocfs2_check_super_or_backup(osb->sb, bh->b_blocknr);
+
+        if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb)) {
+                ret = -EROFS;
+                goto out;
+        }
+
+        lock_buffer(bh);
+        set_buffer_uptodate(bh);
+
+        /* remove from dirty list before I/O. */
+        clear_buffer_dirty(bh);
+
+        get_bh(bh); /* for end_buffer_write_sync() */
+        bh->b_end_io = end_buffer_write_sync;
+        submit_bh(WRITE, bh);
+
+        wait_on_buffer(bh);
+
+        if (!buffer_uptodate(bh)) {
+                ret = -EIO;
+                brelse(bh);
+        }
+
+out:
+        mlog_exit(ret);
+        return ret;
+}