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xfs: factor out filestreams from xfs_bmap_btalloc_nullfb
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There's many if (filestreams) {} else {} branches in this function.
Split it out into a filestreams specific function so that we can
then work directly on cleaning up the filestreams code without
impacting the rest of the allocation algorithms.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
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Dave Chinner committed Feb 12, 2023
1 parent 35bf2b1 commit 89563e7
Showing 1 changed file with 96 additions and 71 deletions.
167 changes: 96 additions & 71 deletions fs/xfs/libxfs/xfs_bmap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3234,8 +3234,8 @@ xfs_bmap_btalloc_select_lengths(
return error;
}

STATIC int
xfs_bmap_btalloc_filestreams(
static int
xfs_bmap_btalloc_filestreams_select_lengths(
struct xfs_bmalloca *ap,
struct xfs_alloc_arg *args,
xfs_extlen_t *blen)
Expand Down Expand Up @@ -3576,54 +3576,109 @@ xfs_bmap_btalloc_at_eof(
return 0;
}

/*
* We have failed multiple allocation attempts so now are in a low space
* allocation situation. Try a locality first full filesystem minimum length
* allocation whilst still maintaining necessary total block reservation
* requirements.
*
* If that fails, we are now critically low on space, so perform a last resort
* allocation attempt: no reserve, no locality, blocking, minimum length, full
* filesystem free space scan. We also indicate to future allocations in this
* transaction that we are critically low on space so they don't waste time on
* allocation modes that are unlikely to succeed.
*/
static int
xfs_bmap_btalloc_best_length(
xfs_bmap_btalloc_low_space(
struct xfs_bmalloca *ap,
struct xfs_alloc_arg *args)
{
int error;

if (args->minlen > ap->minlen) {
args->minlen = ap->minlen;
error = xfs_alloc_vextent_start_ag(args, ap->blkno);
if (error || args->fsbno != NULLFSBLOCK)
return error;
}

/* Last ditch attempt before failure is declared. */
args->total = ap->minlen;
error = xfs_alloc_vextent_first_ag(args, 0);
if (error)
return error;
ap->tp->t_flags |= XFS_TRANS_LOWMODE;
return 0;
}

static int
xfs_bmap_btalloc_filestreams(
struct xfs_bmalloca *ap,
struct xfs_alloc_arg *args,
int stripe_align)
{
struct xfs_mount *mp = args->mp;
xfs_agnumber_t agno = xfs_filestream_lookup_ag(ap->ip);
xfs_extlen_t blen = 0;
bool is_filestream = false;
int error;

if ((ap->datatype & XFS_ALLOC_USERDATA) &&
xfs_inode_is_filestream(ap->ip))
is_filestream = true;
/* Determine the initial block number we will target for allocation. */
if (agno == NULLAGNUMBER)
agno = 0;
ap->blkno = XFS_AGB_TO_FSB(args->mp, agno, 0);
xfs_bmap_adjacent(ap);

/*
* Determine the initial block number we will target for allocation.
* If there is very little free space before we start a
* filestreams allocation, we're almost guaranteed to fail to
* find an AG with enough contiguous free space to succeed, so
* just go straight to the low space algorithm.
*/
if (is_filestream) {
xfs_agnumber_t agno = xfs_filestream_lookup_ag(ap->ip);
if (agno == NULLAGNUMBER)
agno = 0;
ap->blkno = XFS_AGB_TO_FSB(mp, agno, 0);
} else {
ap->blkno = XFS_INO_TO_FSB(mp, ap->ip->i_ino);
if (ap->tp->t_flags & XFS_TRANS_LOWMODE) {
args->minlen = ap->minlen;
return xfs_bmap_btalloc_low_space(ap, args);
}
xfs_bmap_adjacent(ap);

/*
* Search for an allocation group with a single extent large enough for
* the request. If one isn't found, then adjust the minimum allocation
* size to the largest space found.
*/
if (is_filestream) {
/*
* If there is very little free space before we start a
* filestreams allocation, we're almost guaranteed to fail to
* find an AG with enough contiguous free space to succeed, so
* just go straight to the low space algorithm.
*/
if (ap->tp->t_flags & XFS_TRANS_LOWMODE) {
args->minlen = ap->minlen;
goto critically_low_space;
}
error = xfs_bmap_btalloc_filestreams(ap, args, &blen);
} else {
error = xfs_bmap_btalloc_select_lengths(ap, args, &blen);
error = xfs_bmap_btalloc_filestreams_select_lengths(ap, args, &blen);
if (error)
return error;

if (ap->aeof) {
error = xfs_bmap_btalloc_at_eof(ap, args, blen, stripe_align,
true);
if (error || args->fsbno != NULLFSBLOCK)
return error;
}

error = xfs_alloc_vextent_near_bno(args, ap->blkno);
if (error || args->fsbno != NULLFSBLOCK)
return error;

return xfs_bmap_btalloc_low_space(ap, args);
}

static int
xfs_bmap_btalloc_best_length(
struct xfs_bmalloca *ap,
struct xfs_alloc_arg *args,
int stripe_align)
{
xfs_extlen_t blen = 0;
int error;

ap->blkno = XFS_INO_TO_FSB(args->mp, ap->ip->i_ino);
xfs_bmap_adjacent(ap);

/*
* Search for an allocation group with a single extent large enough for
* the request. If one isn't found, then adjust the minimum allocation
* size to the largest space found.
*/
error = xfs_bmap_btalloc_select_lengths(ap, args, &blen);
if (error)
return error;

Expand All @@ -3635,50 +3690,16 @@ xfs_bmap_btalloc_best_length(
*/
if (ap->aeof && !(ap->tp->t_flags & XFS_TRANS_LOWMODE)) {
error = xfs_bmap_btalloc_at_eof(ap, args, blen, stripe_align,
is_filestream);
if (error)
false);
if (error || args->fsbno != NULLFSBLOCK)
return error;
if (args->fsbno != NULLFSBLOCK)
return 0;
}

if (is_filestream)
error = xfs_alloc_vextent_near_bno(args, ap->blkno);
else
error = xfs_alloc_vextent_start_ag(args, ap->blkno);
if (error)
error = xfs_alloc_vextent_start_ag(args, ap->blkno);
if (error || args->fsbno != NULLFSBLOCK)
return error;
if (args->fsbno != NULLFSBLOCK)
return 0;

/*
* Try a locality first full filesystem minimum length allocation whilst
* still maintaining necessary total block reservation requirements.
*/
if (args->minlen > ap->minlen) {
args->minlen = ap->minlen;
error = xfs_alloc_vextent_start_ag(args, ap->blkno);
if (error)
return error;
}
if (args->fsbno != NULLFSBLOCK)
return 0;

/*
* We are now critically low on space, so this is a last resort
* allocation attempt: no reserve, no locality, blocking, minimum
* length, full filesystem free space scan. We also indicate to future
* allocations in this transaction that we are critically low on space
* so they don't waste time on allocation modes that are unlikely to
* succeed.
*/
critically_low_space:
args->total = ap->minlen;
error = xfs_alloc_vextent_first_ag(args, 0);
if (error)
return error;
ap->tp->t_flags |= XFS_TRANS_LOWMODE;
return 0;
return xfs_bmap_btalloc_low_space(ap, args);
}

static int
Expand Down Expand Up @@ -3712,7 +3733,11 @@ xfs_bmap_btalloc(
/* Trim the allocation back to the maximum an AG can fit. */
args.maxlen = min(ap->length, mp->m_ag_max_usable);

error = xfs_bmap_btalloc_best_length(ap, &args, stripe_align);
if ((ap->datatype & XFS_ALLOC_USERDATA) &&
xfs_inode_is_filestream(ap->ip))
error = xfs_bmap_btalloc_filestreams(ap, &args, stripe_align);
else
error = xfs_bmap_btalloc_best_length(ap, &args, stripe_align);
if (error)
return error;

Expand Down

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