On Fri, Jun 21, 2024 at 10:05:32AM +0000, John Garry wrote:
> From: Dave Chinner <dchinner@xxxxxxxxxx>
>
> When forced allocation alignment is specified, the extent will
> be aligned to the extent size hint size rather than stripe
> alignment. If aligned allocation cannot be done, then the allocation
> is failed rather than attempting non-aligned fallbacks.
>
> Note: none of the per-inode force align configuration is present
> yet, so this just triggers off an "always false" wrapper function
> for the moment.
>
> Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
> Signed-off-by: John Garry <john.g.garry@xxxxxxxxxx>
Pretty straightfoward!
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
--D
> ---
> fs/xfs/libxfs/xfs_alloc.h | 1 +
> fs/xfs/libxfs/xfs_bmap.c | 29 +++++++++++++++++++++++------
> fs/xfs/xfs_inode.h | 5 +++++
> 3 files changed, 29 insertions(+), 6 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_alloc.h b/fs/xfs/libxfs/xfs_alloc.h
> index aa2c103d98f0..7de2e6f64882 100644
> --- a/fs/xfs/libxfs/xfs_alloc.h
> +++ b/fs/xfs/libxfs/xfs_alloc.h
> @@ -66,6 +66,7 @@ typedef struct xfs_alloc_arg {
> #define XFS_ALLOC_USERDATA (1 << 0)/* allocation is for user data*/
> #define XFS_ALLOC_INITIAL_USER_DATA (1 << 1)/* special case start of file */
> #define XFS_ALLOC_NOBUSY (1 << 2)/* Busy extents not allowed */
> +#define XFS_ALLOC_FORCEALIGN (1 << 3)/* forced extent alignment */
>
> /* freespace limit calculations */
> unsigned int xfs_alloc_set_aside(struct xfs_mount *mp);
> diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> index 528e3cd81ee6..9131ba8113a6 100644
> --- a/fs/xfs/libxfs/xfs_bmap.c
> +++ b/fs/xfs/libxfs/xfs_bmap.c
> @@ -3401,9 +3401,10 @@ xfs_bmap_alloc_account(
> * Calculate the extent start alignment and the extent length adjustments that
> * constrain this allocation.
> *
> - * Extent start alignment is currently determined by stripe configuration and is
> - * carried in args->alignment, whilst extent length adjustment is determined by
> - * extent size hints and is carried by args->prod and args->mod.
> + * Extent start alignment is currently determined by forced inode alignment or
> + * stripe configuration and is carried in args->alignment, whilst extent length
> + * adjustment is determined by extent size hints and is carried by args->prod
> + * and args->mod.
> *
> * Low level allocation code is free to either ignore or override these values
> * as required.
> @@ -3416,11 +3417,18 @@ xfs_bmap_compute_alignments(
> struct xfs_mount *mp = args->mp;
> xfs_extlen_t align = 0; /* minimum allocation alignment */
>
> - /* stripe alignment for allocation is determined by mount parameters */
> - if (mp->m_swidth && xfs_has_swalloc(mp))
> + /*
> + * Forced inode alignment takes preference over stripe alignment.
> + * Stripe alignment for allocation is determined by mount parameters.
> + */
> + if (xfs_inode_has_forcealign(ap->ip)) {
> + args->alignment = xfs_get_extsz_hint(ap->ip);
> + args->datatype |= XFS_ALLOC_FORCEALIGN;
> + } else if (mp->m_swidth && xfs_has_swalloc(mp)) {
> args->alignment = mp->m_swidth;
> - else if (mp->m_dalign)
> + } else if (mp->m_dalign) {
> args->alignment = mp->m_dalign;
> + }
>
> if (ap->flags & XFS_BMAPI_COWFORK)
> align = xfs_get_cowextsz_hint(ap->ip);
> @@ -3607,6 +3615,11 @@ xfs_bmap_btalloc_low_space(
> {
> int error;
>
> + if (args->alignment > 1 && (args->datatype & XFS_ALLOC_FORCEALIGN)) {
> + args->fsbno = NULLFSBLOCK;
> + return 0;
> + }
> +
> args->alignment = 1;
> if (args->minlen > ap->minlen) {
> args->minlen = ap->minlen;
> @@ -3658,6 +3671,8 @@ xfs_bmap_btalloc_filestreams(
>
> /* Attempt non-aligned allocation if we haven't already. */
> if (!error && args->fsbno == NULLFSBLOCK && args->alignment > 1) {
> + if (args->datatype & XFS_ALLOC_FORCEALIGN)
> + return error;
> args->alignment = 1;
> error = xfs_alloc_vextent_near_bno(args, ap->blkno);
> }
> @@ -3716,6 +3731,8 @@ xfs_bmap_btalloc_best_length(
>
> /* Attempt non-aligned allocation if we haven't already. */
> if (!error && args->fsbno == NULLFSBLOCK && args->alignment > 1) {
> + if (args->datatype & XFS_ALLOC_FORCEALIGN)
> + return error;
> args->alignment = 1;
> error = xfs_alloc_vextent_start_ag(args, ap->blkno);
> }
> diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
> index 292b90b5f2ac..42f999c1106c 100644
> --- a/fs/xfs/xfs_inode.h
> +++ b/fs/xfs/xfs_inode.h
> @@ -311,6 +311,11 @@ static inline bool xfs_inode_has_large_extent_counts(struct xfs_inode *ip)
> return ip->i_diflags2 & XFS_DIFLAG2_NREXT64;
> }
>
> +static inline bool xfs_inode_has_forcealign(struct xfs_inode *ip)
> +{
> + return false;
> +}
> +
> /*
> * Decide if this file is a realtime file whose data allocation unit is larger
> * than a single filesystem block.
> --
> 2.31.1
>
>
