[PATCH 35/42] xfs: merge new filestream AG selection into xfs_filestream_select_ag()

Dave Chinner
2023-02-09T22:26:47Z

This is largely a wrapper around xfs_filestream_pick_ag() that
repeats a lot of the lookups that we just merged back into
xfs_filestream_select_ag() from the lookup code. Merge the
xfs_filestream_new_ag() code back into _select_ag() to get rid
of all the unnecessary logic.

Indeed, this makes it obvious that if we have no parent inode,
the filestreams allocator always selects AG 0 regardless of whether
it is fit for purpose or not.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/xfs_filestream.c | 112 ++++++++++++++--------------------------
1 file changed, 40 insertions(+), 72 deletions(-)

diff --git a/fs/xfs/xfs_filestream.c b/fs/xfs/xfs_filestream.c
index 23044dab2001..713766729dcf 100644
--- a/fs/xfs/xfs_filestream.c
+++ b/fs/xfs/xfs_filestream.c
@@ -98,16 +98,18 @@ xfs_fstrm_free_func(
static int
xfs_filestream_pick_ag(
struct xfs_inode *ip,
- xfs_agnumber_t startag,
xfs_agnumber_t *agp,
int flags,
- xfs_extlen_t minlen)
+ xfs_extlen_t *longest)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_fstrm_item *item;
struct xfs_perag *pag;
- xfs_extlen_t longest, free = 0, minfree, maxfree = 0;
- xfs_agnumber_t ag, max_ag = NULLAGNUMBER;
+ xfs_extlen_t minlen = *longest;
+ xfs_extlen_t free = 0, minfree, maxfree = 0;
+ xfs_agnumber_t startag = *agp;
+ xfs_agnumber_t ag = startag;
+ xfs_agnumber_t max_ag = NULLAGNUMBER;
int err, trylock, nscan;

ASSERT(S_ISDIR(VFS_I(ip)->i_mode));
@@ -115,7 +117,6 @@ xfs_filestream_pick_ag(
/* 2% of an AG's blocks must be free for it to be chosen. */
minfree = mp->m_sb.sb_agblocks / 50;

- ag = startag;
*agp = NULLAGNUMBER;

/* For the first pass, don't sleep trying to init the per-AG. */
@@ -125,8 +126,8 @@ xfs_filestream_pick_ag(
trace_xfs_filestream_scan(mp, ip->i_ino, ag);

pag = xfs_perag_get(mp, ag);
- longest = 0;
- err = xfs_bmap_longest_free_extent(pag, NULL, &longest);
+ *longest = 0;
+ err = xfs_bmap_longest_free_extent(pag, NULL, longest);
if (err) {
xfs_perag_put(pag);
if (err != -EAGAIN)
@@ -152,7 +153,7 @@ xfs_filestream_pick_ag(
goto next_ag;
}

- if (((minlen && longest >= minlen) ||
+ if (((minlen && *longest >= minlen) ||
(!minlen && pag->pagf_freeblks >= minfree)) &&
(!xfs_perag_prefers_metadata(pag) ||
!(flags & XFS_PICK_USERDATA) ||
@@ -258,58 +259,6 @@ xfs_filestream_get_parent(
return dir ? XFS_I(dir) : NULL;
}

-/*
- * Pick a new allocation group for the current file and its file stream.
- *
- * This is called when the allocator can't find a suitable extent in the
- * current AG, and we have to move the stream into a new AG with more space.
- */
-static int
-xfs_filestream_new_ag(
- struct xfs_bmalloca *ap,
- xfs_agnumber_t *agp)
-{
- struct xfs_inode *ip = ap->ip, *pip;
- struct xfs_mount *mp = ip->i_mount;
- xfs_extlen_t minlen = ap->length;
- xfs_agnumber_t startag = 0;
- int flags = 0;
- int err = 0;
- struct xfs_mru_cache_elem *mru;
-
- *agp = NULLAGNUMBER;
-
- pip = xfs_filestream_get_parent(ip);
- if (!pip)
- goto exit;
-
- mru = xfs_mru_cache_remove(mp->m_filestream, pip->i_ino);
- if (mru) {
- struct xfs_fstrm_item *item =
- container_of(mru, struct xfs_fstrm_item, mru);
- startag = (item->ag + 1) % mp->m_sb.sb_agcount;
- }
-
- if (ap->datatype & XFS_ALLOC_USERDATA)
- flags |= XFS_PICK_USERDATA;
- if (ap->tp->t_flags & XFS_TRANS_LOWMODE)
- flags |= XFS_PICK_LOWSPACE;
-
- err = xfs_filestream_pick_ag(pip, startag, agp, flags, minlen);
-
- /*
- * Only free the item here so we skip over the old AG earlier.
- */
- if (mru)
- xfs_fstrm_free_func(mp, mru);
-
- xfs_irele(pip);
-exit:
- if (*agp == NULLAGNUMBER)
- *agp = 0;
- return err;
-}
-
/*
* Search for an allocation group with a single extent large enough for
* the request. If one isn't found, then the largest available free extent is
@@ -326,6 +275,7 @@ xfs_filestream_select_ag(
struct xfs_inode *pip = NULL;
xfs_agnumber_t agno = NULLAGNUMBER;
struct xfs_mru_cache_elem *mru;
+ int flags = 0;
int error;

args->total = ap->total;
@@ -334,13 +284,14 @@ xfs_filestream_select_ag(
pip = xfs_filestream_get_parent(ap->ip);
if (!pip) {
agno = 0;
- goto new_ag;
+ goto out_select;
}

mru = xfs_mru_cache_lookup(mp->m_filestream, pip->i_ino);
if (mru) {
agno = container_of(mru, struct xfs_fstrm_item, mru)->ag;
xfs_mru_cache_done(mp->m_filestream);
+ mru = NULL;

trace_xfs_filestream_lookup(mp, ap->ip->i_ino, agno);
xfs_irele(pip);
@@ -354,7 +305,7 @@ xfs_filestream_select_ag(
xfs_perag_rele(pag);
if (error) {
if (error != -EAGAIN)
- return error;
+ goto out_error;
*blen = 0;
}
}
@@ -366,13 +317,18 @@ xfs_filestream_select_ag(
mp->m_sb.sb_agcount;
mp->m_agfrotor = (mp->m_agfrotor + 1) %
(mp->m_sb.sb_agcount * rotorstep);
- xfs_irele(pip);
} else {
agno = XFS_INO_TO_AGNO(mp, pip->i_ino);
- xfs_irele(pip);
}

-new_ag:
+ /* Changing parent AG association now, so remove the existing one. */
+ mru = xfs_mru_cache_remove(mp->m_filestream, pip->i_ino);
+ if (mru) {
+ struct xfs_fstrm_item *item =
+ container_of(mru, struct xfs_fstrm_item, mru);
+ agno = (item->ag + 1) % mp->m_sb.sb_agcount;
+ xfs_fstrm_free_func(mp, mru);
+ }
ap->blkno = XFS_AGB_TO_FSB(args->mp, agno, 0);
xfs_bmap_adjacent(ap);

@@ -382,34 +338,46 @@ xfs_filestream_select_ag(
* larger free space available so we don't even try.
*/
if (ap->tp->t_flags & XFS_TRANS_LOWMODE)
- return 0;
+ goto out_select;

- error = xfs_filestream_new_ag(ap, &agno);
+ if (ap->datatype & XFS_ALLOC_USERDATA)
+ flags |= XFS_PICK_USERDATA;
+ if (ap->tp->t_flags & XFS_TRANS_LOWMODE)
+ flags |= XFS_PICK_LOWSPACE;
+
+ *blen = ap->length;
+ error = xfs_filestream_pick_ag(pip, &agno, flags, blen);
if (error)
- return error;
+ goto out_error;
if (agno == NULLAGNUMBER) {
agno = 0;
- goto out_select;
+ goto out_irele;
}

pag = xfs_perag_grab(mp, agno);
if (!pag)
- goto out_select;
+ goto out_irele;

error = xfs_bmap_longest_free_extent(pag, args->tp, blen);
xfs_perag_rele(pag);
if (error) {
if (error != -EAGAIN)
- return error;
+ goto out_error;
*blen = 0;
}

+out_irele:
+ xfs_irele(pip);
out_select:
ap->blkno = XFS_AGB_TO_FSB(mp, agno, 0);
return 0;
+
+out_error:
+ xfs_irele(pip);
+ return error;
+
}

-
void
xfs_filestream_deassociate(
struct xfs_inode *ip)
--
2.39.0