linux/fs/gfs2/trans.c
Andreas Gruenbacher 2129b42888 gfs2: Per-revoke accounting in transactions
In the log, revokes are stored as a revoke descriptor (struct
gfs2_log_descriptor), followed by zero or more additional revoke blocks
(struct gfs2_meta_header).  On filesystems with a blocksize of 4k, the
revoke descriptor contains up to 503 revokes, and the metadata blocks
contain up to 509 revokes each.  We've so far been reserving space for
revokes in transactions in block granularity, so a lot more space than
necessary was being allocated and then released again.

This patch switches to assigning revokes to transactions individually
instead.  Initially, space for the revoke descriptor is reserved and
handed out to transactions.  When more revokes than that are reserved,
additional revoke blocks are added.  When the log is flushed, the space
for the additional revoke blocks is released, but we keep the space for
the revoke descriptor block allocated.

Transactions may still reserve more revokes than they will actually need
in the end, but now we won't overshoot the target as much, and by only
returning the space for excess revokes at log flush time, we further
reduce the amount of contention between processes.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-02-22 21:16:23 +01:00

330 lines
9.1 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/kallsyms.h>
#include <linux/gfs2_ondisk.h>
#include "gfs2.h"
#include "incore.h"
#include "glock.h"
#include "inode.h"
#include "log.h"
#include "lops.h"
#include "meta_io.h"
#include "trans.h"
#include "util.h"
#include "trace_gfs2.h"
static void gfs2_print_trans(struct gfs2_sbd *sdp, const struct gfs2_trans *tr)
{
fs_warn(sdp, "Transaction created at: %pSR\n", (void *)tr->tr_ip);
fs_warn(sdp, "blocks=%u revokes=%u reserved=%u touched=%u\n",
tr->tr_blocks, tr->tr_revokes, tr->tr_reserved,
test_bit(TR_TOUCHED, &tr->tr_flags));
fs_warn(sdp, "Buf %u/%u Databuf %u/%u Revoke %u\n",
tr->tr_num_buf_new, tr->tr_num_buf_rm,
tr->tr_num_databuf_new, tr->tr_num_databuf_rm,
tr->tr_num_revoke);
}
int __gfs2_trans_begin(struct gfs2_trans *tr, struct gfs2_sbd *sdp,
unsigned int blocks, unsigned int revokes,
unsigned long ip)
{
unsigned int extra_revokes;
if (current->journal_info) {
gfs2_print_trans(sdp, current->journal_info);
BUG();
}
BUG_ON(blocks == 0 && revokes == 0);
if (!test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags))
return -EROFS;
tr->tr_ip = ip;
tr->tr_blocks = blocks;
tr->tr_revokes = revokes;
tr->tr_reserved = GFS2_LOG_FLUSH_MIN_BLOCKS;
if (blocks) {
/*
* The reserved blocks are either used for data or metadata.
* We can have mixed data and metadata, each with its own log
* descriptor block; see calc_reserved().
*/
tr->tr_reserved += blocks + 1 + DIV_ROUND_UP(blocks - 1, databuf_limit(sdp));
}
INIT_LIST_HEAD(&tr->tr_databuf);
INIT_LIST_HEAD(&tr->tr_buf);
INIT_LIST_HEAD(&tr->tr_list);
INIT_LIST_HEAD(&tr->tr_ail1_list);
INIT_LIST_HEAD(&tr->tr_ail2_list);
if (gfs2_assert_warn(sdp, tr->tr_reserved <= sdp->sd_jdesc->jd_blocks))
return -EINVAL;
sb_start_intwrite(sdp->sd_vfs);
/*
* Try the reservations under sd_log_flush_lock to prevent log flushes
* from creating inconsistencies between the number of allocated and
* reserved revokes. If that fails, do a full-block allocation outside
* of the lock to avoid stalling log flushes. Then, allot the
* appropriate number of blocks to revokes, use as many revokes locally
* as needed, and "release" the surplus into the revokes pool.
*/
down_read(&sdp->sd_log_flush_lock);
if (gfs2_log_try_reserve(sdp, tr, &extra_revokes))
goto reserved;
up_read(&sdp->sd_log_flush_lock);
gfs2_log_reserve(sdp, tr, &extra_revokes);
down_read(&sdp->sd_log_flush_lock);
reserved:
gfs2_log_release_revokes(sdp, extra_revokes);
if (unlikely(!test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags))) {
gfs2_log_release_revokes(sdp, tr->tr_revokes);
up_read(&sdp->sd_log_flush_lock);
gfs2_log_release(sdp, tr->tr_reserved);
sb_end_intwrite(sdp->sd_vfs);
return -EROFS;
}
current->journal_info = tr;
return 0;
}
int gfs2_trans_begin(struct gfs2_sbd *sdp, unsigned int blocks,
unsigned int revokes)
{
struct gfs2_trans *tr;
int error;
tr = kmem_cache_zalloc(gfs2_trans_cachep, GFP_NOFS);
if (!tr)
return -ENOMEM;
error = __gfs2_trans_begin(tr, sdp, blocks, revokes, _RET_IP_);
if (error)
kmem_cache_free(gfs2_trans_cachep, tr);
return error;
}
void gfs2_trans_end(struct gfs2_sbd *sdp)
{
struct gfs2_trans *tr = current->journal_info;
s64 nbuf;
current->journal_info = NULL;
if (!test_bit(TR_TOUCHED, &tr->tr_flags)) {
gfs2_log_release_revokes(sdp, tr->tr_revokes);
up_read(&sdp->sd_log_flush_lock);
gfs2_log_release(sdp, tr->tr_reserved);
if (!test_bit(TR_ONSTACK, &tr->tr_flags))
gfs2_trans_free(sdp, tr);
sb_end_intwrite(sdp->sd_vfs);
return;
}
gfs2_log_release_revokes(sdp, tr->tr_revokes - tr->tr_num_revoke);
nbuf = tr->tr_num_buf_new + tr->tr_num_databuf_new;
nbuf -= tr->tr_num_buf_rm;
nbuf -= tr->tr_num_databuf_rm;
if (gfs2_assert_withdraw(sdp, nbuf <= tr->tr_blocks) ||
gfs2_assert_withdraw(sdp, tr->tr_num_revoke <= tr->tr_revokes))
gfs2_print_trans(sdp, tr);
gfs2_log_commit(sdp, tr);
if (!test_bit(TR_ONSTACK, &tr->tr_flags) &&
!test_bit(TR_ATTACHED, &tr->tr_flags))
gfs2_trans_free(sdp, tr);
up_read(&sdp->sd_log_flush_lock);
if (sdp->sd_vfs->s_flags & SB_SYNCHRONOUS)
gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL |
GFS2_LFC_TRANS_END);
sb_end_intwrite(sdp->sd_vfs);
}
static struct gfs2_bufdata *gfs2_alloc_bufdata(struct gfs2_glock *gl,
struct buffer_head *bh)
{
struct gfs2_bufdata *bd;
bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL);
bd->bd_bh = bh;
bd->bd_gl = gl;
INIT_LIST_HEAD(&bd->bd_list);
bh->b_private = bd;
return bd;
}
/**
* gfs2_trans_add_data - Add a databuf to the transaction.
* @gl: The inode glock associated with the buffer
* @bh: The buffer to add
*
* This is used in journaled data mode.
* We need to journal the data block in the same way as metadata in
* the functions above. The difference is that here we have a tag
* which is two __be64's being the block number (as per meta data)
* and a flag which says whether the data block needs escaping or
* not. This means we need a new log entry for each 251 or so data
* blocks, which isn't an enormous overhead but twice as much as
* for normal metadata blocks.
*/
void gfs2_trans_add_data(struct gfs2_glock *gl, struct buffer_head *bh)
{
struct gfs2_trans *tr = current->journal_info;
struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
struct gfs2_bufdata *bd;
lock_buffer(bh);
if (buffer_pinned(bh)) {
set_bit(TR_TOUCHED, &tr->tr_flags);
goto out;
}
gfs2_log_lock(sdp);
bd = bh->b_private;
if (bd == NULL) {
gfs2_log_unlock(sdp);
unlock_buffer(bh);
if (bh->b_private == NULL)
bd = gfs2_alloc_bufdata(gl, bh);
else
bd = bh->b_private;
lock_buffer(bh);
gfs2_log_lock(sdp);
}
gfs2_assert(sdp, bd->bd_gl == gl);
set_bit(TR_TOUCHED, &tr->tr_flags);
if (list_empty(&bd->bd_list)) {
set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
gfs2_pin(sdp, bd->bd_bh);
tr->tr_num_databuf_new++;
list_add_tail(&bd->bd_list, &tr->tr_databuf);
}
gfs2_log_unlock(sdp);
out:
unlock_buffer(bh);
}
void gfs2_trans_add_meta(struct gfs2_glock *gl, struct buffer_head *bh)
{
struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
struct gfs2_bufdata *bd;
struct gfs2_meta_header *mh;
struct gfs2_trans *tr = current->journal_info;
enum gfs2_freeze_state state = atomic_read(&sdp->sd_freeze_state);
lock_buffer(bh);
if (buffer_pinned(bh)) {
set_bit(TR_TOUCHED, &tr->tr_flags);
goto out;
}
gfs2_log_lock(sdp);
bd = bh->b_private;
if (bd == NULL) {
gfs2_log_unlock(sdp);
unlock_buffer(bh);
lock_page(bh->b_page);
if (bh->b_private == NULL)
bd = gfs2_alloc_bufdata(gl, bh);
else
bd = bh->b_private;
unlock_page(bh->b_page);
lock_buffer(bh);
gfs2_log_lock(sdp);
}
gfs2_assert(sdp, bd->bd_gl == gl);
set_bit(TR_TOUCHED, &tr->tr_flags);
if (!list_empty(&bd->bd_list))
goto out_unlock;
set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
mh = (struct gfs2_meta_header *)bd->bd_bh->b_data;
if (unlikely(mh->mh_magic != cpu_to_be32(GFS2_MAGIC))) {
fs_err(sdp, "Attempting to add uninitialised block to "
"journal (inplace block=%lld)\n",
(unsigned long long)bd->bd_bh->b_blocknr);
BUG();
}
if (unlikely(state == SFS_FROZEN)) {
fs_info(sdp, "GFS2:adding buf while frozen\n");
gfs2_assert_withdraw(sdp, 0);
}
if (unlikely(gfs2_withdrawn(sdp))) {
fs_info(sdp, "GFS2:adding buf while withdrawn! 0x%llx\n",
(unsigned long long)bd->bd_bh->b_blocknr);
}
gfs2_pin(sdp, bd->bd_bh);
mh->__pad0 = cpu_to_be64(0);
mh->mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
list_add(&bd->bd_list, &tr->tr_buf);
tr->tr_num_buf_new++;
out_unlock:
gfs2_log_unlock(sdp);
out:
unlock_buffer(bh);
}
void gfs2_trans_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
{
struct gfs2_trans *tr = current->journal_info;
BUG_ON(!list_empty(&bd->bd_list));
gfs2_add_revoke(sdp, bd);
set_bit(TR_TOUCHED, &tr->tr_flags);
tr->tr_num_revoke++;
}
void gfs2_trans_remove_revoke(struct gfs2_sbd *sdp, u64 blkno, unsigned int len)
{
struct gfs2_bufdata *bd, *tmp;
unsigned int n = len;
gfs2_log_lock(sdp);
list_for_each_entry_safe(bd, tmp, &sdp->sd_log_revokes, bd_list) {
if ((bd->bd_blkno >= blkno) && (bd->bd_blkno < (blkno + len))) {
list_del_init(&bd->bd_list);
gfs2_assert_withdraw(sdp, sdp->sd_log_num_revoke);
sdp->sd_log_num_revoke--;
if (bd->bd_gl)
gfs2_glock_remove_revoke(bd->bd_gl);
kmem_cache_free(gfs2_bufdata_cachep, bd);
gfs2_log_release_revokes(sdp, 1);
if (--n == 0)
break;
}
}
gfs2_log_unlock(sdp);
}
void gfs2_trans_free(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
{
if (tr == NULL)
return;
gfs2_assert_warn(sdp, list_empty(&tr->tr_ail1_list));
gfs2_assert_warn(sdp, list_empty(&tr->tr_ail2_list));
gfs2_assert_warn(sdp, list_empty(&tr->tr_databuf));
gfs2_assert_warn(sdp, list_empty(&tr->tr_buf));
kmem_cache_free(gfs2_trans_cachep, tr);
}