On Wed, May 12, 2021 at 06:01:58PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@xxxxxxxxxx>
>
> The RTINHERIT bit can be set on a directory so that newly created
> regular files will have the REALTIME bit set to store their data on the
> realtime volume. If an extent size hint (and EXTSZINHERIT) are set on
> the directory, the hint will also be copied into the new file.
>
> As pointed out in previous patches, for realtime files we require the
> extent size hint be an integer multiple of the realtime extent, but we
> don't perform the same validation on a directory with both RTINHERIT and
> EXTSZINHERIT set, even though the only use-case of that combination is
> to propagate extent size hints into new realtime files. This leads to
> inode corruption errors when the bad values are propagated.
>
> Strengthen the validation routine to avoid this situation and fix the
> open-coded unit conversion while we're at it. Note that this is
> technically a breaking change to the ondisk format, but the risk should
> be minimal because (a) most vendors disable realtime, (b) letting
> unaligned hints propagate to new files would immediately crash the
> filesystem, and (c) xfs_repair flags such filesystems as corrupt, so
> anyone with such a configuration is broken already anyway.
>
> Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
> ---
Ok, so this looks more like a proper fix, but does this turn an existing
directory with (rtinherit && extszinherit) and a badly aligned extsz
hint into a read validation error?
Brian
> fs/xfs/libxfs/xfs_inode_buf.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
>
> diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
> index 5c9a7440d9e4..25261dd73290 100644
> --- a/fs/xfs/libxfs/xfs_inode_buf.c
> +++ b/fs/xfs/libxfs/xfs_inode_buf.c
> @@ -569,19 +569,20 @@ xfs_inode_validate_extsize(
> uint16_t mode,
> uint16_t flags)
> {
> - bool rt_flag;
> + bool rt_flag, rtinherit_flag;
> bool hint_flag;
> bool inherit_flag;
> uint32_t extsize_bytes;
> uint32_t blocksize_bytes;
>
> rt_flag = (flags & XFS_DIFLAG_REALTIME);
> + rtinherit_flag = (flags & XFS_DIFLAG_RTINHERIT);
> hint_flag = (flags & XFS_DIFLAG_EXTSIZE);
> inherit_flag = (flags & XFS_DIFLAG_EXTSZINHERIT);
> extsize_bytes = XFS_FSB_TO_B(mp, extsize);
>
> - if (rt_flag)
> - blocksize_bytes = mp->m_sb.sb_rextsize << mp->m_sb.sb_blocklog;
> + if (rt_flag || (rtinherit_flag && inherit_flag))
> + blocksize_bytes = XFS_FSB_TO_B(mp, mp->m_sb.sb_rextsize);
> else
> blocksize_bytes = mp->m_sb.sb_blocksize;
>
>
