[PATCH 34/42] xfs: merge filestream AG lookup into xfs_filestream_select_ag()

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

The lookup currently either returns the cached filestream AG or it
calls xfs_filestreams_select_lengths() to looks up a new AG. This
has verify the AG that is selected, so we end up doing "select a new
AG loop in a couple of places when only one really is needed. Merge
the initial lookup functionality with the length selection so that
we only need to do a single pick loop on lookup or verification
failure.

This undoes a lot of the factoring that enabled the selection to be
moved over to the filestreams code. It makes
xfs_filestream_select_ag() an awful messier, but it has to be made
worse before it can get better in future patches...

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/xfs_filestream.c | 196 ++++++++++++++++------------------------
1 file changed, 76 insertions(+), 120 deletions(-)

diff --git a/fs/xfs/xfs_filestream.c b/fs/xfs/xfs_filestream.c
index a641404aa9a6..23044dab2001 100644
--- a/fs/xfs/xfs_filestream.c
+++ b/fs/xfs/xfs_filestream.c
@@ -258,55 +258,6 @@ xfs_filestream_get_parent(
return dir ? XFS_I(dir) : NULL;
}

-/*
- * Find the right allocation group for a file, either by finding an
- * existing file stream or creating a new one.
- *
- * Returns NULLAGNUMBER in case of an error.
- */
-static xfs_agnumber_t
-xfs_filestream_lookup_ag(
- struct xfs_inode *ip)
-{
- struct xfs_mount *mp = ip->i_mount;
- struct xfs_inode *pip = NULL;
- xfs_agnumber_t startag, ag = NULLAGNUMBER;
- struct xfs_mru_cache_elem *mru;
-
- ASSERT(S_ISREG(VFS_I(ip)->i_mode));
-
- pip = xfs_filestream_get_parent(ip);
- if (!pip)
- return NULLAGNUMBER;
-
- mru = xfs_mru_cache_lookup(mp->m_filestream, pip->i_ino);
- if (mru) {
- ag = container_of(mru, struct xfs_fstrm_item, mru)->ag;
- xfs_mru_cache_done(mp->m_filestream);
-
- trace_xfs_filestream_lookup(mp, ip->i_ino, ag);
- goto out;
- }
-
- /*
- * Set the starting AG using the rotor for inode32, otherwise
- * use the directory inode's AG.
- */
- if (xfs_is_inode32(mp)) {
- xfs_agnumber_t rotorstep = xfs_rotorstep;
- startag = (mp->m_agfrotor / rotorstep) % mp->m_sb.sb_agcount;
- mp->m_agfrotor = (mp->m_agfrotor + 1) %
- (mp->m_sb.sb_agcount * rotorstep);
- } else
- startag = XFS_INO_TO_AGNO(mp, pip->i_ino);
-
- if (xfs_filestream_pick_ag(pip, startag, &ag, 0, 0))
- ag = NULLAGNUMBER;
-out:
- xfs_irele(pip);
- return ag;
-}
-
/*
* Pick a new allocation group for the current file and its file stream.
*
@@ -359,66 +310,6 @@ xfs_filestream_new_ag(
return err;
}

-static int
-xfs_filestreams_select_lengths(
- struct xfs_bmalloca *ap,
- struct xfs_alloc_arg *args,
- xfs_extlen_t *blen)
-{
- struct xfs_mount *mp = ap->ip->i_mount;
- struct xfs_perag *pag;
- xfs_agnumber_t start_agno;
- int error;
-
- args->total = ap->total;
-
- start_agno = XFS_FSB_TO_AGNO(mp, ap->blkno);
- if (start_agno == NULLAGNUMBER)
- start_agno = 0;
-
- pag = xfs_perag_grab(mp, start_agno);
- if (pag) {
- error = xfs_bmap_longest_free_extent(pag, args->tp, blen);
- xfs_perag_rele(pag);
- if (error) {
- if (error != -EAGAIN)
- return error;
- *blen = 0;
- }
- }
-
- if (*blen < args->maxlen) {
- xfs_agnumber_t agno = start_agno;
-
- error = xfs_filestream_new_ag(ap, &agno);
- if (error)
- return error;
- if (agno == NULLAGNUMBER)
- goto out_select;
-
- pag = xfs_perag_grab(mp, agno);
- if (!pag)
- goto out_select;
-
- error = xfs_bmap_longest_free_extent(pag, args->tp, blen);
- xfs_perag_rele(pag);
- if (error) {
- if (error != -EAGAIN)
- return error;
- *blen = 0;
- }
- start_agno = agno;
- }
-
-out_select:
- /*
- * Set the failure fallback case to look in the selected AG as stream
- * may have moved.
- */
- ap->blkno = args->fsbno = XFS_AGB_TO_FSB(mp, start_agno, 0);
- return 0;
-}
-
/*
* 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
@@ -430,12 +321,59 @@ xfs_filestream_select_ag(
struct xfs_alloc_arg *args,
xfs_extlen_t *blen)
{
- xfs_agnumber_t start_agno = xfs_filestream_lookup_ag(ap->ip);
+ struct xfs_mount *mp = ap->ip->i_mount;
+ struct xfs_perag *pag;
+ struct xfs_inode *pip = NULL;
+ xfs_agnumber_t agno = NULLAGNUMBER;
+ struct xfs_mru_cache_elem *mru;
+ int error;

- /* Determine the initial block number we will target for allocation. */
- if (start_agno == NULLAGNUMBER)
- start_agno = 0;
- ap->blkno = XFS_AGB_TO_FSB(args->mp, start_agno, 0);
+ args->total = ap->total;
+ *blen = 0;
+
+ pip = xfs_filestream_get_parent(ap->ip);
+ if (!pip) {
+ agno = 0;
+ goto new_ag;
+ }
+
+ 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);
+
+ trace_xfs_filestream_lookup(mp, ap->ip->i_ino, agno);
+ xfs_irele(pip);
+
+ ap->blkno = XFS_AGB_TO_FSB(args->mp, agno, 0);
+ xfs_bmap_adjacent(ap);
+
+ pag = xfs_perag_grab(mp, agno);
+ if (pag) {
+ error = xfs_bmap_longest_free_extent(pag, args->tp, blen);
+ xfs_perag_rele(pag);
+ if (error) {
+ if (error != -EAGAIN)
+ return error;
+ *blen = 0;
+ }
+ }
+ if (*blen >= args->maxlen)
+ goto out_select;
+ } else if (xfs_is_inode32(mp)) {
+ xfs_agnumber_t rotorstep = xfs_rotorstep;
+ agno = (mp->m_agfrotor / rotorstep) %
+ 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:
+ ap->blkno = XFS_AGB_TO_FSB(args->mp, agno, 0);
xfs_bmap_adjacent(ap);

/*
@@ -446,14 +384,32 @@ xfs_filestream_select_ag(
if (ap->tp->t_flags & XFS_TRANS_LOWMODE)
return 0;

- /*
- * 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.
- */
- return xfs_filestreams_select_lengths(ap, args, blen);
+ error = xfs_filestream_new_ag(ap, &agno);
+ if (error)
+ return error;
+ if (agno == NULLAGNUMBER) {
+ agno = 0;
+ goto out_select;
+ }
+
+ pag = xfs_perag_grab(mp, agno);
+ if (!pag)
+ goto out_select;
+
+ error = xfs_bmap_longest_free_extent(pag, args->tp, blen);
+ xfs_perag_rele(pag);
+ if (error) {
+ if (error != -EAGAIN)
+ return error;
+ *blen = 0;
+ }
+
+out_select:
+ ap->blkno = XFS_AGB_TO_FSB(mp, agno, 0);
+ return 0;
}

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