@@ -2391,7 +2391,7 @@ xfs_alloc_space_available(
reservation = xfs_ag_resv_needed(pag, args->resv);
/* do we have enough contiguous free space for the allocation? */
- alloc_len = args->minlen + (args->alignment - 1) + args->minalignslop;
+ alloc_len = args->minlen + (args->alignment - 1) + args->alignslop;
longest = xfs_alloc_longest_free_extent(pag, min_free, reservation);
if (longest < alloc_len)
return false;
@@ -2420,7 +2420,7 @@ xfs_alloc_space_available(
* allocation as we know that will definitely succeed and match the
* callers alignment constraints.
*/
- alloc_len = args->maxlen + (args->alignment - 1) + args->minalignslop;
+ alloc_len = args->maxlen + (args->alignment - 1) + args->alignslop;
if (longest < alloc_len) {
args->maxlen = args->minlen;
ASSERT(args->maxlen > 0);
@@ -46,7 +46,7 @@ typedef struct xfs_alloc_arg {
xfs_extlen_t minleft; /* min blocks must be left after us */
xfs_extlen_t total; /* total blocks needed in xaction */
xfs_extlen_t alignment; /* align answer to multiple of this */
- xfs_extlen_t minalignslop; /* slop for minlen+alignment calcs */
+ xfs_extlen_t alignslop; /* slop for alignment calcs */
xfs_agblock_t min_agbno; /* set an agbno range for NEAR allocs */
xfs_agblock_t max_agbno; /* ... */
xfs_extlen_t len; /* output: actual size of extent */
@@ -3285,6 +3285,10 @@ xfs_bmap_select_minlen(
xfs_extlen_t blen)
{
+ /* Adjust best length for extent start alignment. */
+ if (blen > args->alignment)
+ blen -= args->alignment;
+
/*
* Since we used XFS_ALLOC_FLAG_TRYLOCK in _longest_free_extent(), it is
* possible that there is enough contiguous free space for this request.
@@ -3393,35 +3397,43 @@ xfs_bmap_alloc_account(
xfs_trans_mod_dquot_byino(ap->tp, ap->ip, fld, ap->length);
}
-static int
+/*
+ * 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.
+ *
+ * Low level allocation code is free to either ignore or override these values
+ * as required.
+ */
+static void
xfs_bmap_compute_alignments(
struct xfs_bmalloca *ap,
struct xfs_alloc_arg *args)
{
struct xfs_mount *mp = args->mp;
xfs_extlen_t align = 0; /* minimum allocation alignment */
- int stripe_align = 0;
/* stripe alignment for allocation is determined by mount parameters */
if (mp->m_swidth && xfs_has_swalloc(mp))
- stripe_align = mp->m_swidth;
+ args->alignment = mp->m_swidth;
else if (mp->m_dalign)
- stripe_align = mp->m_dalign;
+ args->alignment = mp->m_dalign;
if (ap->flags & XFS_BMAPI_COWFORK)
align = xfs_get_cowextsz_hint(ap->ip);
else if (ap->datatype & XFS_ALLOC_USERDATA)
align = xfs_get_extsz_hint(ap->ip);
+
if (align) {
if (xfs_bmap_extsize_align(mp, &ap->got, &ap->prev, align, 0,
ap->eof, 0, ap->conv, &ap->offset,
&ap->length))
ASSERT(0);
ASSERT(ap->length);
- }
- /* apply extent size hints if obtained earlier */
- if (align) {
args->prod = align;
div_u64_rem(ap->offset, args->prod, &args->mod);
if (args->mod)
@@ -3436,7 +3448,6 @@ xfs_bmap_compute_alignments(
args->mod = args->prod - args->mod;
}
- return stripe_align;
}
static void
@@ -3508,7 +3519,7 @@ xfs_bmap_exact_minlen_extent_alloc(
args.total = ap->total;
args.alignment = 1;
- args.minalignslop = 0;
+ args.alignslop = 0;
args.minleft = ap->minleft;
args.wasdel = ap->wasdel;
@@ -3548,7 +3559,6 @@ xfs_bmap_btalloc_at_eof(
struct xfs_bmalloca *ap,
struct xfs_alloc_arg *args,
xfs_extlen_t blen,
- int stripe_align,
bool ag_only)
{
struct xfs_mount *mp = args->mp;
@@ -3562,23 +3572,15 @@ xfs_bmap_btalloc_at_eof(
* allocation.
*/
if (ap->offset) {
- xfs_extlen_t nextminlen = 0;
+ xfs_extlen_t alignment = args->alignment;
/*
- * Compute the minlen+alignment for the next case. Set slop so
- * that the value of minlen+alignment+slop doesn't go up between
- * the calls.
+ * Compute the alignment slop for the fallback path so we ensure
+ * we account for the potential alignment space required by the
+ * fallback paths before we modify the AGF and AGFL here.
*/
args->alignment = 1;
- if (blen > stripe_align && blen <= args->maxlen)
- nextminlen = blen - stripe_align;
- else
- nextminlen = args->minlen;
- if (nextminlen + stripe_align > args->minlen + 1)
- args->minalignslop = nextminlen + stripe_align -
- args->minlen - 1;
- else
- args->minalignslop = 0;
+ args->alignslop = alignment - args->alignment;
if (!caller_pag)
args->pag = xfs_perag_get(mp, XFS_FSB_TO_AGNO(mp, ap->blkno));
@@ -3596,19 +3598,8 @@ xfs_bmap_btalloc_at_eof(
* Exact allocation failed. Reset to try an aligned allocation
* according to the original allocation specification.
*/
- args->alignment = stripe_align;
- args->minlen = nextminlen;
- args->minalignslop = 0;
- } else {
- /*
- * Adjust minlen to try and preserve alignment if we
- * can't guarantee an aligned maxlen extent.
- */
- args->alignment = stripe_align;
- if (blen > args->alignment &&
- blen <= args->maxlen + args->alignment)
- args->minlen = blen - args->alignment;
- args->minalignslop = 0;
+ args->alignment = alignment;
+ args->alignslop = 0;
}
if (ag_only) {
@@ -3626,9 +3617,8 @@ xfs_bmap_btalloc_at_eof(
return 0;
/*
- * Allocation failed, so turn return the allocation args to their
- * original non-aligned state so the caller can proceed on allocation
- * failure as if this function was never called.
+ * Aligned allocation failed, so all fallback paths from here drop the
+ * start alignment requirement as we know it will not succeed.
*/
args->alignment = 1;
return 0;
@@ -3636,7 +3626,9 @@ xfs_bmap_btalloc_at_eof(
/*
* We have failed multiple allocation attempts so now are in a low space
- * allocation situation. Try a locality first full filesystem minimum length
+ * allocation situation. We give up on any attempt at aligned allocation here.
+ *
+ * Try a locality first full filesystem minimum length
* allocation whilst still maintaining necessary total block reservation
* requirements.
*
@@ -3653,6 +3645,7 @@ xfs_bmap_btalloc_low_space(
{
int error;
+ args->alignment = 1;
if (args->minlen > ap->minlen) {
args->minlen = ap->minlen;
error = xfs_alloc_vextent_start_ag(args, ap->blkno);
@@ -3672,13 +3665,11 @@ xfs_bmap_btalloc_low_space(
static int
xfs_bmap_btalloc_filestreams(
struct xfs_bmalloca *ap,
- struct xfs_alloc_arg *args,
- int stripe_align)
+ struct xfs_alloc_arg *args)
{
xfs_extlen_t blen = 0;
int error = 0;
-
error = xfs_filestream_select_ag(ap, args, &blen);
if (error)
return error;
@@ -3697,8 +3688,7 @@ xfs_bmap_btalloc_filestreams(
args->minlen = xfs_bmap_select_minlen(ap, args, blen);
if (ap->aeof)
- error = xfs_bmap_btalloc_at_eof(ap, args, blen, stripe_align,
- true);
+ error = xfs_bmap_btalloc_at_eof(ap, args, blen, true);
if (!error && args->fsbno == NULLFSBLOCK)
error = xfs_alloc_vextent_near_bno(args, ap->blkno);
@@ -3722,8 +3712,7 @@ xfs_bmap_btalloc_filestreams(
static int
xfs_bmap_btalloc_best_length(
struct xfs_bmalloca *ap,
- struct xfs_alloc_arg *args,
- int stripe_align)
+ struct xfs_alloc_arg *args)
{
xfs_extlen_t blen = 0;
int error;
@@ -3747,8 +3736,7 @@ xfs_bmap_btalloc_best_length(
* trying.
*/
if (ap->aeof && !(ap->tp->t_flags & XFS_TRANS_LOWMODE)) {
- error = xfs_bmap_btalloc_at_eof(ap, args, blen, stripe_align,
- false);
+ error = xfs_bmap_btalloc_at_eof(ap, args, blen, false);
if (error || args->fsbno != NULLFSBLOCK)
return error;
}
@@ -3775,27 +3763,26 @@ xfs_bmap_btalloc(
.resv = XFS_AG_RESV_NONE,
.datatype = ap->datatype,
.alignment = 1,
- .minalignslop = 0,
+ .alignslop = 0,
};
xfs_fileoff_t orig_offset;
xfs_extlen_t orig_length;
int error;
- int stripe_align;
ASSERT(ap->length);
orig_offset = ap->offset;
orig_length = ap->length;
- stripe_align = xfs_bmap_compute_alignments(ap, &args);
+ xfs_bmap_compute_alignments(ap, &args);
/* Trim the allocation back to the maximum an AG can fit. */
args.maxlen = min(ap->length, mp->m_ag_max_usable);
if ((ap->datatype & XFS_ALLOC_USERDATA) &&
xfs_inode_is_filestream(ap->ip))
- error = xfs_bmap_btalloc_filestreams(ap, &args, stripe_align);
+ error = xfs_bmap_btalloc_filestreams(ap, &args);
else
- error = xfs_bmap_btalloc_best_length(ap, &args, stripe_align);
+ error = xfs_bmap_btalloc_best_length(ap, &args);
if (error)
return error;
@@ -758,12 +758,12 @@ xfs_ialloc_ag_alloc(
*
* For an exact allocation, alignment must be 1,
* however we need to take cluster alignment into account when
- * fixing up the freelist. Use the minalignslop field to
- * indicate that extra blocks might be required for alignment,
- * but not to use them in the actual exact allocation.
+ * fixing up the freelist. Use the alignslop field to indicate
+ * that extra blocks might be required for alignment, but not
+ * to use them in the actual exact allocation.
*/
args.alignment = 1;
- args.minalignslop = igeo->cluster_align - 1;
+ args.alignslop = igeo->cluster_align - 1;
/* Allow space for the inode btree to split. */
args.minleft = igeo->inobt_maxlevels;
@@ -783,7 +783,7 @@ xfs_ialloc_ag_alloc(
* on, so reset minalignslop to ensure it is not included in
* subsequent requests.
*/
- args.minalignslop = 0;
+ args.alignslop = 0;
}
if (unlikely(args.fsbno == NULLFSBLOCK)) {
@@ -1808,7 +1808,7 @@ DECLARE_EVENT_CLASS(xfs_alloc_class,
__field(xfs_extlen_t, minleft)
__field(xfs_extlen_t, total)
__field(xfs_extlen_t, alignment)
- __field(xfs_extlen_t, minalignslop)
+ __field(xfs_extlen_t, alignslop)
__field(xfs_extlen_t, len)
__field(char, wasdel)
__field(char, wasfromfl)
@@ -1827,7 +1827,7 @@ DECLARE_EVENT_CLASS(xfs_alloc_class,
__entry->minleft = args->minleft;
__entry->total = args->total;
__entry->alignment = args->alignment;
- __entry->minalignslop = args->minalignslop;
+ __entry->alignslop = args->alignslop;
__entry->len = args->len;
__entry->wasdel = args->wasdel;
__entry->wasfromfl = args->wasfromfl;
@@ -1836,7 +1836,7 @@ DECLARE_EVENT_CLASS(xfs_alloc_class,
__entry->highest_agno = args->tp->t_highest_agno;
),
TP_printk("dev %d:%d agno 0x%x agbno 0x%x minlen %u maxlen %u mod %u "
- "prod %u minleft %u total %u alignment %u minalignslop %u "
+ "prod %u minleft %u total %u alignment %u alignslop %u "
"len %u wasdel %d wasfromfl %d resv %d "
"datatype 0x%x highest_agno 0x%x",
MAJOR(__entry->dev), MINOR(__entry->dev),
@@ -1849,7 +1849,7 @@ DECLARE_EVENT_CLASS(xfs_alloc_class,
__entry->minleft,
__entry->total,
__entry->alignment,
- __entry->minalignslop,
+ __entry->alignslop,
__entry->len,
__entry->wasdel,
__entry->wasfromfl,