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xfs: merge new filestream AG selection into xfs_filestream_select_ag()
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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>
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Dave Chinner committed Feb 12, 2023
1 parent a52dc2a commit ba34de8
Showing 1 changed file with 40 additions and 72 deletions.
112 changes: 40 additions & 72 deletions fs/xfs/xfs_filestream.c
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Original file line number Diff line number Diff line change
Expand Up @@ -98,24 +98,25 @@ 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));

/* 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. */
Expand All @@ -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)
Expand All @@ -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) ||
Expand Down Expand Up @@ -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
Expand All @@ -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;
Expand All @@ -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);
Expand All @@ -354,7 +305,7 @@ xfs_filestream_select_ag(
xfs_perag_rele(pag);
if (error) {
if (error != -EAGAIN)
return error;
goto out_error;
*blen = 0;
}
}
Expand All @@ -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);

Expand All @@ -382,33 +338,45 @@ 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;

if (ap->datatype & XFS_ALLOC_USERDATA)
flags |= XFS_PICK_USERDATA;
if (ap->tp->t_flags & XFS_TRANS_LOWMODE)
flags |= XFS_PICK_LOWSPACE;

error = xfs_filestream_new_ag(ap, &agno);
*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(
Expand Down

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