From 8fbb1877dfa5e26bda1baf8cc6abd3f805098486 Mon Sep 17 00:00:00 2001 From: Yuto Ohnuki Date: Sat, 11 Apr 2026 15:24:14 +0100 Subject: [PATCH] xfs: zero directory data block padding on write verification Old kernels did not zero the pad field in xfs_dir3_data_hdr when initializing directory data blocks, so existing filesystems may have non-zero padding on disk. Zero the pad field in xfs_dir3_data_write_verify alongside the existing LSN and checksum updates. The pad field is pure alignment padding with no runtime meaning, so zeroing it during write verification is safe and has no additional I/O cost. This lets filesystems gradually self-heal stale non-zero padding as directories are modified, without requiring an explicit repair pass. Suggested-by: Dave Chinner Signed-off-by: Yuto Ohnuki Reviewed-by: Darrick J. Wong Signed-off-by: Carlos Maiolino --- fs/xfs/libxfs/xfs_dir2_data.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/xfs/libxfs/xfs_dir2_data.c b/fs/xfs/libxfs/xfs_dir2_data.c index 35ff119aa84b..aecbab61014c 100644 --- a/fs/xfs/libxfs/xfs_dir2_data.c +++ b/fs/xfs/libxfs/xfs_dir2_data.c @@ -382,6 +382,7 @@ xfs_dir3_data_write_verify( struct xfs_mount *mp = bp->b_mount; struct xfs_buf_log_item *bip = bp->b_log_item; struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr; + struct xfs_dir3_data_hdr *datahdr3 = bp->b_addr; xfs_failaddr_t fa; fa = xfs_dir3_data_verify(bp); @@ -396,6 +397,11 @@ xfs_dir3_data_write_verify( if (bip) hdr3->lsn = cpu_to_be64(bip->bli_item.li_lsn); + /* + * Zero padding that may be stale from old kernels. + */ + datahdr3->pad = 0; + xfs_buf_update_cksum(bp, XFS_DIR3_DATA_CRC_OFF); }