Re: [PATCH v4 13/22] xfs: Unmap blocks according to forcealign

John Garry
2024-06-11T10:08:33Z

On 07/06/2024 15:39, John Garry wrote:
> For when forcealign is enabled, blocks in an inode need to be unmapped
> according to extent alignment, like what is already done for rtvol.
>
> Signed-off-by: John Garry <john.g.garry@oracle.com>
> ---
> fs/xfs/libxfs/xfs_bmap.c | 33 ++++++++++++++++++++++++++++-----
> 1 file changed, 28 insertions(+), 5 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> index c9cf138e13c4..2b6d5ebd8b4f 100644
> --- a/fs/xfs/libxfs/xfs_bmap.c
> +++ b/fs/xfs/libxfs/xfs_bmap.c
> @@ -5380,6 +5380,20 @@ xfs_bmap_del_extent_real(
> return 0;
> }
>
> +static xfs_extlen_t
> +xfs_bunmapi_align(
> + struct xfs_inode *ip,
> + xfs_fsblock_t bno)
> +{
> + if (xfs_inode_has_forcealign(ip)) {
> + if (is_power_of_2(ip->i_extsize))
> + return bno & (ip->i_extsize - 1);
> + return do_div(bno, ip->i_extsize);
> + }
> + ASSERT(XFS_IS_REALTIME_INODE(ip));
> + return xfs_rtb_to_rtxoff(ip->i_mount, bno);
> +}

This following updated version of xfs_bunmapi_align() seems to fix the
issue reported in
https://lore.kernel.org/linux-xfs/d96c6e91-44f0-41c5-bebc-a092dc8a8406@oracle.com/

static xfs_extlen_t
xfs_bunmapi_align(
struct xfs_inode *ip,
xfs_fsblock_t fsbno)
{
if (xfs_inode_has_forcealign(ip)) {
struct xfs_mount *mp = ip->i_mount;
xfs_agblock_t agbno = XFS_FSB_TO_AGBNO(mp,
fsbno);

if (is_power_of_2(ip->i_extsize))
return agbno & (ip->i_extsize - 1);
return do_div(agbno, ip->i_extsize);
}
ASSERT(XFS_IS_REALTIME_INODE(ip));
return xfs_rtb_to_rtxoff(ip->i_mount, fsbno);
}

> +
> /*
> * Unmap (remove) blocks from a file.
> * If nexts is nonzero then the number of extents to remove is limited to
> @@ -5402,6 +5416,7 @@ __xfs_bunmapi(
> struct xfs_bmbt_irec got; /* current extent record */
> struct xfs_ifork *ifp; /* inode fork pointer */
> int isrt; /* freeing in rt area */
> + int isforcealign; /* freeing for inode with forcealign */
> int logflags; /* transaction logging flags */
> xfs_extlen_t mod; /* rt extent offset */
> struct xfs_mount *mp = ip->i_mount;
> @@ -5439,6 +5454,8 @@ __xfs_bunmapi(
> }
> XFS_STATS_INC(mp, xs_blk_unmap);
> isrt = xfs_ifork_is_realtime(ip, whichfork);
> + isforcealign = (whichfork != XFS_ATTR_FORK) &&
> + xfs_inode_has_forcealign(ip);
> end = start + len;
>
> if (!xfs_iext_lookup_extent_before(ip, ifp, &end, &icur, &got)) {
> @@ -5490,11 +5507,10 @@ __xfs_bunmapi(
> if (del.br_startoff + del.br_blockcount > end + 1)
> del.br_blockcount = end + 1 - del.br_startoff;
>
> - if (!isrt || (flags & XFS_BMAPI_REMAP))
> + if ((!isrt && !isforcealign) || (flags & XFS_BMAPI_REMAP))
> goto delete;
>
> - mod = xfs_rtb_to_rtxoff(mp,
> - del.br_startblock + del.br_blockcount);
> + mod = xfs_bunmapi_align(ip, del.br_startblock + del.br_blockcount);
> if (mod) {
> /*
> * Realtime extent not lined up at the end.
> @@ -5542,9 +5558,16 @@ __xfs_bunmapi(
> goto nodelete;
> }
>
> - mod = xfs_rtb_to_rtxoff(mp, del.br_startblock);
> + mod = xfs_bunmapi_align(ip, del.br_startblock);
> if (mod) {
> - xfs_extlen_t off = mp->m_sb.sb_rextsize - mod;
> + xfs_extlen_t off;
> +
> + if (isforcealign) {
> + off = ip->i_extsize - mod;
> + } else {
> + ASSERT(isrt);
> + off = mp->m_sb.sb_rextsize - mod;
> + }
>
> /*
> * Realtime extent is lined up at the end but not