f2fs: refactor f2fs_commit_super

Previously, f2fs_commit_super hacks the bh->blocknr to write the broken
alternate superblock.
Instead of it, we should use the correct logic to retrieve its buffer head
with locking it appropriately.

Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index bd7e9c6c42c80f5ac65a2a8a43a2ad9f8508e407..dbf16ade0e9a71b4c344bfd2642d3bcb56cce06f 100644 (file)
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1099,27 +1099,35 @@ out:
 int f2fs_commit_super(struct f2fs_sb_info *sbi, bool recover)
 {
        struct buffer_head *sbh = sbi->raw_super_buf;
-       sector_t block = sbh->b_blocknr;
+       struct buffer_head *bh;
        int err;
 
        /* write back-up superblock first */
-       sbh->b_blocknr = block ? 0 : 1;
-       mark_buffer_dirty(sbh);
-       err = sync_dirty_buffer(sbh);
+       bh = sb_getblk(sbi->sb, sbh->b_blocknr ? 0 : 1);
+       if (!bh)
+               return -EIO;
 
-       sbh->b_blocknr = block;
+       lock_buffer(bh);
+       memcpy(bh->b_data, sbh->b_data, sbh->b_size);
+       WARN_ON(sbh->b_size != F2FS_BLKSIZE);
+       set_buffer_uptodate(bh);
+       set_buffer_dirty(bh);
+       unlock_buffer(bh);
+
+       /* it's rare case, we can do fua all the time */
+       err = __sync_dirty_buffer(bh, WRITE_FLUSH_FUA);
+       brelse(bh);
 
        /* if we are in recovery path, skip writing valid superblock */
        if (recover || err)
-               goto out;
+               return err;
 
        /* write current valid superblock */
-       mark_buffer_dirty(sbh);
-       err = sync_dirty_buffer(sbh);
-out:
-       clear_buffer_write_io_error(sbh);
-       set_buffer_uptodate(sbh);
-       return err;
+       lock_buffer(sbh);
+       set_buffer_dirty(sbh);
+       unlock_buffer(sbh);
+
+       return __sync_dirty_buffer(sbh, WRITE_FLUSH_FUA);
 }
 
 static int f2fs_fill_super(struct super_block *sb, void *data, int silent)