// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2006-2007 Silicon Graphics, Inc.
* Copyright (c) 2014 Christoph Hellwig.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_bmap.h"
#include "xfs_bmap_util.h"
#include "xfs_alloc.h"
#include "xfs_mru_cache.h"
#include "xfs_trace.h"
#include "xfs_ag.h"
#include "xfs_ag_resv.h"
#include "xfs_trans.h"
#include "xfs_filestream.h"
struct xfs_fstrm_item {
struct xfs_mru_cache_elem mru;
struct xfs_perag *pag; /* AG in use for this directory */
};
enum xfs_fstrm_alloc {
XFS_PICK_USERDATA = 1,
XFS_PICK_LOWSPACE = 2,
};
static void
xfs_fstrm_free_func(
void *data,
struct xfs_mru_cache_elem *mru)
{
struct xfs_fstrm_item *item =
container_of(mru, struct xfs_fstrm_item, mru);
struct xfs_perag *pag = item->pag;
trace_xfs_filestream_free(pag, mru->key);
atomic_dec(&pag->pagf_fstrms);
xfs_perag_rele(pag);
kfree(item);
}
/*
* Scan the AGs starting at start_agno looking for an AG that isn't in use and
* has at least minlen blocks free. If no AG is found to match the allocation
* requirements, pick the AG with the most free space in it.
*/
static int
xfs_filestream_pick_ag(
struct xfs_alloc_arg *args,
xfs_ino_t pino,
xfs_agnumber_t start_agno,
int flags,
xfs_extlen_t *longest)
{
struct xfs_mount *mp = args->mp;
struct xfs_perag *pag;
struct xfs_perag *max_pag = NULL;
xfs_extlen_t minlen = *longest;
xfs_extlen_t free = 0, minfree, maxfree = 0;
xfs_agnumber_t agno;
bool first_pass = true;
int err;
/* 2% of an AG's blocks must be free for it to be chosen. */
minfree = mp->m_sb.sb_agblocks / 50;
restart:
for_each_perag_wrap(mp, start_agno, agno, pag) {
trace_xfs_filestream_scan(pag, pino);
*longest = 0;
err = xfs_bmap_longest_free_extent(pag, NULL, longest);
if (err) {
if (err != -EAGAIN)
break;
/* Couldn't lock the AGF, skip this AG. */
err = 0;
continue;
}
/* Keep track of the AG with the most free blocks. */
if (pag->pagf_freeblks > maxfree) {
maxfree = pag->pagf_freeblks;
if (max_pag)
xfs_perag_rele(max_pag);
atomic_inc(&pag->pag_active_ref);
max_pag = pag;
}
/*
* The AG reference count does two things: it enforces mutual
* exclusion when examining the suitability of an AG in this
* loop, and it guards against two filestreams being established
* in the same AG as each other.
*/
if (atomic_inc_return(&pag->pagf_fstrms) <= 1) {
if (((minlen && *longest >= minlen) ||
(!minlen && pag->pagf_freeblks >= minfree)) &&
(!xfs_perag_prefers_metadata(pag) ||
!(flags & XFS_PICK_USERDATA) ||
(flags & XFS_PICK_LOWSPACE))) {
/* Break out, retaining the reference on the AG. */
free = pag->pagf_freeblks;
break;
}
}
/* Drop the reference on this AG, it's not usable. */
atomic_dec(&pag->pagf_fstrms);
}
if (err) {
xfs_perag_rele(pag);
if (max_pag)
xfs_perag_rele(max_pag);
return err;
}
if (!pag) {
/*
* Allow a second pass to give xfs_bmap_longest_free_extent()
* another attempt at locking AGFs that it might have skipped
* over before we fail.
*/
if (first_pass) {
first_pass = false;
goto restart;
}
/*
* We must be low on data space, so run a final lowspace
* optimised selection pass if we haven't already.
*/
if (!(flags & XFS_PICK_LOWSPACE)) {
flags |= XFS_PICK_LOWSPACE;
goto restart;
}
/*
* No unassociated AGs are available, so select the AG with the
* most free space, regardless of whether it's already in use by
* another filestream. It none suit, just use whatever AG we can
* grab.
*/
if (!max_pag) {
for_each_perag_wrap(args->mp, 0, start_agno, args->pag)
break;
atomic_inc(&args->pag->pagf_fstrms);
*longest = 0;
} else {
pag = max_pag;
free = maxfree;
atomic_inc(&pag->pagf_fstrms);
}
} else if (max_pag) {
xfs_perag_rele(max_pag);
}
trace_xfs_filestream_pick(pag, pino, free);
args->pag = pag;
return 0;
}
static struct xfs_inode *
xfs_filestream_get_parent(
struct xfs_inode *ip)
{
struct inode *inode = VFS_I(ip), *dir = NULL;
struct dentry *dentry, *parent;
dentry = d_find_alias(inode);
if (!dentry)
goto out;
parent = dget_parent(dentry);
if (!parent)
goto out_dput;
dir = igrab(d_inode(parent));
dput(parent);
out_dput:
dput(dentry);
out:
return dir ? XFS_I(dir) : NULL;
}
/*
* Lookup the mru cache for an existing association. If one exists and we can
* use it, return with an active perag reference indicating that the allocation
* will proceed with that association.
*
* If we have no association, or we cannot use the current one and have to
* destroy it, return with longest = 0 to tell the caller to create a new
* association.
*/
static int
xfs_filestream_lookup_association(
struct xfs_bmalloca *ap,
struct xfs_alloc_arg *args,
xfs_ino_t pino,
xfs_extlen_t *longest)
{
struct xfs_mount *mp = args->mp;
struct xfs_perag *pag;
struct xfs_mru_cache_elem *mru;
int error = 0;
*longest = 0;
mru = xfs_mru_cache_lookup(mp->m_filestream, pino);
if (!mru)
return 0;
/*
* Grab the pag and take an extra active reference for the caller whilst
* the mru item cannot go away. This means we'll pin the perag with
* the reference we get here even if the filestreams association is torn
* down immediately after we mark the lookup as done.
*/
pag = container_of(mru, struct xfs_fstrm_item, mru)->pag;
atomic_inc(&pag->pag_active_ref);
xfs_mru_cache_done(mp->m_filestream);
trace_xfs_filestream_lookup(pag, ap->ip->i_ino);
ap->blkno = XFS_AGB_TO_FSB(args->mp, pag->pag_agno, 0);
xfs_bmap_adjacent(ap);
/*
* If there is very little free space before we start a filestreams
* allocation, we're almost guaranteed to fail to find a large enough
* free space available so just use the cached AG.
*/
if (ap->tp->t_flags & XFS_TRANS_LOWMODE) {
*longest = 1;
goto out_done;
}
error = xfs_bmap_longest_free_extent(pag, args->tp, longest);
if (error == -EAGAIN)
error = 0;
if (error || *longest < args->maxlen) {
/* We aren't going to use this perag */
*longest = 0;
xfs_perag_rele(pag);
return error;
}
out_done:
args->pag = pag;
return 0;
}
static int
xfs_filestream_create_association(
struct xfs_bmalloca *ap,
struct xfs_alloc_arg *args,
xfs_ino_t pino,
xfs_extlen_t *longest)
{
struct xfs_mount *mp = args->mp;
struct xfs_mru_cache_elem *mru;
struct xfs_fstrm_item *item;
xfs_agnumber_t agno = XFS_INO_TO_AGNO(mp, pino);
int flags = 0;
int error;
/* Changing parent AG association now, so remove the existing one. */
mru = xfs_mru_cache_remove(mp->m_filestream, pino);
if (mru) {
struct xfs_fstrm_item *item =
container_of(mru, struct xfs_fstrm_item, mru);
agno = (item->pag->pag_agno + 1) % mp->m_sb.sb_agcount;
xfs_fstrm_free_func(mp, mru);
} 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);
}
ap->blkno = XFS_AGB_TO_FSB(args->mp, agno, 0);
xfs_bmap_adjacent(ap);
if (ap->datatype & XFS_ALLOC_USERDATA)
flags |= XFS_PICK_USERDATA;
if (ap->tp->t_flags & XFS_TRANS_LOWMODE)
flags |= XFS_PICK_LOWSPACE;
*longest = ap->length;
error = xfs_filestream_pick_ag(args, pino, agno, flags, longest);
if (error)
return error;
/*
* We are going to use this perag now, so create an assoication for it.
* xfs_filestream_pick_ag() has already bumped the perag fstrms counter
* for us, so all we need to do here is take another active reference to
* the perag for the cached association.
*
* If we fail to store the association, we need to drop the fstrms
* counter as well as drop the perag reference we take here for the
* item. We do not need to return an error for this failure - as long as
* we return a referenced AG, the allocation can still go ahead just
* fine.
*/
item = kmalloc(sizeof(*item), GFP_KERNEL | __GFP_RETRY_MAYFAIL);
if (!item)
goto out_put_fstrms;
atomic_inc(&args->pag->pag_active_ref);
item->pag = args->pag;
error = xfs_mru_cache_insert(mp->m_filestream, pino, &item->mru);
if (error)
goto out_free_item;
return 0;
out_free_item:
xfs_perag_rele(item->pag);
kfree(item);
out_put_fstrms:
atomic_dec(&args->pag->pagf_fstrms);
return 0;
}
/*
* Search for an allocation group with a single extent large enough for
* the request. First we look for an existing association and use that if it
* is found. Otherwise, we create a new association by selecting an AG that fits
* the allocation criteria.
*
* We return with a referenced perag in args->pag to indicate which AG we are
* allocating into or an error with no references held.
*/
int
xfs_filestream_select_ag(
struct xfs_bmalloca *ap,
struct xfs_alloc_arg *args,
xfs_extlen_t *longest)
{
struct xfs_mount *mp = args->mp;
struct xfs_inode *pip;
xfs_ino_t ino = 0;
int error = 0;
*longest = 0;
args->total = ap->total;
pip = xfs_filestream_get_parent(ap->ip);
if (pip) {
ino = pip->i_ino;
error = xfs_filestream_lookup_association(ap, args, ino,
longest);
xfs_irele(pip);
if (error)
return error;
if (*longest >= args->maxlen)
goto out_select;
if (ap->tp->t_flags & XFS_TRANS_LOWMODE)
goto out_select;
}
error = xfs_filestream_create_association(ap, args, ino, longest);
if (error)
return error;
out_select:
ap->blkno = XFS_AGB_TO_FSB(mp, args->pag->pag_agno, 0);
return 0;
}
void
xfs_filestream_deassociate(
struct xfs_inode *ip)
{
xfs_mru_cache_delete(ip->i_mount->m_filestream, ip->i_ino);
}
int
xfs_filestream_mount(
xfs_mount_t *mp)
{
/*
* The filestream timer tunable is currently fixed within the range of
* one second to four minutes, with five seconds being the default. The
* group count is somewhat arbitrary, but it'd be nice to adhere to the
* timer tunable to within about 10 percent. This requires at least 10
* groups.
*/
return xfs_mru_cache_create(&mp->m_filestream, mp,
xfs_fstrm_centisecs * 10, 10, xfs_fstrm_free_func);
}
void
xfs_filestream_unmount(
xfs_mount_t *mp)
{
xfs_mru_cache_destroy(mp->m_filestream);
}
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