[PATCH 2/2] xfs: update dir3 leaf block metadata after swap

From: Jiachen Zhang <zhangjiachen.jaycee@bytedance.com>
To: Chandan Babu R <chandan.babu@oracle.com>,
	"Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <dchinner@redhat.com>,
	Allison Henderson <allison.henderson@oracle.com>,
	Zhang Tianci <zhangtianci.1997@bytedance.com>,
	Brian Foster <bfoster@redhat.com>, Ben Myers <bpm@sgi.com>,
	linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org,
	xieyongji@bytedance.com, me@jcix.top
Subject: [PATCH 2/2] xfs: update dir3 leaf block metadata after swap
Date: Tue, 28 Nov 2023 13:32:02 +0800	[thread overview]
Message-ID: <20231128053202.29007-3-zhangjiachen.jaycee@bytedance.com> (raw)
In-Reply-To: <20231128053202.29007-1-zhangjiachen.jaycee@bytedance.com>

From: Zhang Tianci <zhangtianci.1997@bytedance.com>

xfs_da3_swap_lastblock() copy the last block content to the dead block,
but do not update the metadata in it. We need update some metadata
for some kinds of type block, such as dir3 leafn block records its
blkno, we shall update it to the dead block blkno. Otherwise,
before write the xfs_buf to disk, the verify_write() will fail in
blk_hdr->blkno != xfs_buf->b_bn, then xfs will be shutdown.

We will get this warning:

  XFS (dm-0): Metadata corruption detected at xfs_dir3_leaf_verify+0xa8/0xe0 [xfs], xfs_dir3_leafn block 0x178
  XFS (dm-0): Unmount and run xfs_repair
  XFS (dm-0): First 128 bytes of corrupted metadata buffer:
  00000000e80f1917: 00 80 00 0b 00 80 00 07 3d ff 00 00 00 00 00 00  ........=.......
  000000009604c005: 00 00 00 00 00 00 01 a0 00 00 00 00 00 00 00 00  ................
  000000006b6fb2bf: e4 44 e3 97 b5 64 44 41 8b 84 60 0e 50 43 d9 bf  .D...dDA..`.PC..
  00000000678978a2: 00 00 00 00 00 00 00 83 01 73 00 93 00 00 00 00  .........s......
  00000000b28b247c: 99 29 1d 38 00 00 00 00 99 29 1d 40 00 00 00 00  .).8.....).@....
  000000002b2a662c: 99 29 1d 48 00 00 00 00 99 49 11 00 00 00 00 00  .).H.....I......
  00000000ea2ffbb8: 99 49 11 08 00 00 45 25 99 49 11 10 00 00 48 fe  .I....E%.I....H.
  0000000069e86440: 99 49 11 18 00 00 4c 6b 99 49 11 20 00 00 4d 97  .I....Lk.I. ..M.
  XFS (dm-0): xfs_do_force_shutdown(0x8) called from line 1423 of file fs/xfs/xfs_buf.c.  Return address = 00000000c0ff63c1
  XFS (dm-0): Corruption of in-memory data detected.  Shutting down filesystem
  XFS (dm-0): Please umount the filesystem and rectify the problem(s)

From the log above, we know xfs_buf->b_no is 0x178, but the block's hdr record
its blkno is 0x1a0.

Fixes: 24df33b45ecf ("xfs: add CRC checking to dir2 leaf blocks")
Signed-off-by: Zhang Tianci <zhangtianci.1997@bytedance.com>
---
 fs/xfs/libxfs/xfs_da_btree.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/libxfs/xfs_da_btree.c b/fs/xfs/libxfs/xfs_da_btree.c
index e576560b46e9..35f70e4c6447 100644
--- a/fs/xfs/libxfs/xfs_da_btree.c
+++ b/fs/xfs/libxfs/xfs_da_btree.c
@@ -2318,8 +2318,18 @@ xfs_da3_swap_lastblock(
 	 * Copy the last block into the dead buffer and log it.
 	 */
 	memcpy(dead_buf->b_addr, last_buf->b_addr, args->geo->blksize);
-	xfs_trans_log_buf(tp, dead_buf, 0, args->geo->blksize - 1);
 	dead_info = dead_buf->b_addr;
+	/*
+	 * Update the moved block's blkno if it's a dir3 leaf block
+	 */
+	if (dead_info->magic == cpu_to_be16(XFS_DIR3_LEAF1_MAGIC) ||
+	    dead_info->magic == cpu_to_be16(XFS_DIR3_LEAFN_MAGIC) ||
+	    dead_info->magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC)) {
+		struct xfs_da3_blkinfo *dap = (struct xfs_da3_blkinfo *)dead_info;
+
+		dap->blkno = cpu_to_be64(dead_buf->b_bn);
+	}
+	xfs_trans_log_buf(tp, dead_buf, 0, args->geo->blksize - 1);
 	/*
 	 * Get values from the moved block.
 	 */
-- 
2.20.1

