[PATCH 2/3] f2fs: refactor f2fs_commit_super

From: Jaegeuk Kim
Date: Mon Dec 07 2015 - 17:54:39 EST


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.

Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
fs/f2fs/super.c | 32 ++++++++++++++++++++------------
1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index bd7e9c6..dbf16ad 100644
--- 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)
--
2.4.9 (Apple Git-60)

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