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alistair23-linux/fs/gfs2/trans.c
Steven Whitehouse 4513899092 GFS2: Use ->writepages for ordered writes 
Instead of using a list of buffers to write ahead of the journal
flush, this now uses a list of inodes and calls ->writepages
via filemap_fdatawrite() in order to achieve the same thing. For
most use cases this results in a shorter ordered write list,
as well as much larger i/os being issued.

The ordered write list is sorted by inode number before writing
in order to retain the disk block ordering between inodes as
per the previous code.

The previous ordered write code used to conflict in its assumptions
about how to write out the disk blocks with mpage_writepages()
so that with this updated version we can also use mpage_writepages()
for GFS2's ordered write, writepages implementation. So we will
also send larger i/os from writeback too.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-01-29 10:29:17 +00:00

306 lines
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/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License version 2.
*/
#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"
int gfs2_trans_begin(struct gfs2_sbd *sdp, unsigned int blocks,
unsigned int revokes)
{
struct gfs2_trans *tr;
int error;
BUG_ON(current->journal_info);
BUG_ON(blocks == 0 && revokes == 0);
if (!test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags))
return -EROFS;
tr = kzalloc(sizeof(struct gfs2_trans), GFP_NOFS);
if (!tr)
return -ENOMEM;
tr->tr_ip = (unsigned long)__builtin_return_address(0);
tr->tr_blocks = blocks;
tr->tr_revokes = revokes;
tr->tr_reserved = 1;
if (blocks)
tr->tr_reserved += 6 + blocks;
if (revokes)
tr->tr_reserved += gfs2_struct2blk(sdp, revokes,
sizeof(u64));
sb_start_intwrite(sdp->sd_vfs);
gfs2_holder_init(sdp->sd_trans_gl, LM_ST_SHARED, 0, &tr->tr_t_gh);
error = gfs2_glock_nq(&tr->tr_t_gh);
if (error)
goto fail_holder_uninit;
error = gfs2_log_reserve(sdp, tr->tr_reserved);
if (error)
goto fail_gunlock;
current->journal_info = tr;
return 0;
fail_gunlock:
gfs2_glock_dq(&tr->tr_t_gh);
fail_holder_uninit:
sb_end_intwrite(sdp->sd_vfs);
gfs2_holder_uninit(&tr->tr_t_gh);
kfree(tr);
return error;
}
/**
* gfs2_log_release - Release a given number of log blocks
* @sdp: The GFS2 superblock
* @blks: The number of blocks
*
*/
static void gfs2_log_release(struct gfs2_sbd *sdp, unsigned int blks)
{
atomic_add(blks, &sdp->sd_log_blks_free);
trace_gfs2_log_blocks(sdp, blks);
gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
sdp->sd_jdesc->jd_blocks);
up_read(&sdp->sd_log_flush_lock);
}
static void gfs2_print_trans(const struct gfs2_trans *tr)
{
print_symbol(KERN_WARNING "GFS2: Transaction created at: %s\n", tr->tr_ip);
printk(KERN_WARNING "GFS2: blocks=%u revokes=%u reserved=%u touched=%d\n",
tr->tr_blocks, tr->tr_revokes, tr->tr_reserved, tr->tr_touched);
printk(KERN_WARNING "GFS2: Buf %u/%u Databuf %u/%u Revoke %u/%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, tr->tr_num_revoke_rm);
}
void gfs2_trans_end(struct gfs2_sbd *sdp)
{
struct gfs2_trans *tr = current->journal_info;
s64 nbuf;
BUG_ON(!tr);
current->journal_info = NULL;
if (!tr->tr_touched) {
gfs2_log_release(sdp, tr->tr_reserved);
if (tr->tr_t_gh.gh_gl) {
gfs2_glock_dq(&tr->tr_t_gh);
gfs2_holder_uninit(&tr->tr_t_gh);
kfree(tr);
}
sb_end_intwrite(sdp->sd_vfs);
return;
}
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) &&
(tr->tr_num_revoke <= tr->tr_revokes)))
gfs2_print_trans(tr);
gfs2_log_commit(sdp, tr);
if (tr->tr_t_gh.gh_gl) {
gfs2_glock_dq(&tr->tr_t_gh);
gfs2_holder_uninit(&tr->tr_t_gh);
kfree(tr);
}
if (sdp->sd_vfs->s_flags & MS_SYNCHRONOUS)
gfs2_log_flush(sdp, NULL);
sb_end_intwrite(sdp->sd_vfs);
}
static struct gfs2_bufdata *gfs2_alloc_bufdata(struct gfs2_glock *gl,
struct buffer_head *bh,
const struct gfs2_log_operations *lops)
{
struct gfs2_bufdata *bd;
bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL);
bd->bd_bh = bh;
bd->bd_gl = gl;
bd->bd_ops = lops;
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 two distinct cases:
* i) In ordered write mode
* We put the data buffer on a list so that we can ensure that its
* synced to disk at the right time
* ii) 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_sbd;
struct address_space *mapping = bh->b_page->mapping;
struct gfs2_inode *ip = GFS2_I(mapping->host);
struct gfs2_bufdata *bd;
if (!gfs2_is_jdata(ip)) {
gfs2_ordered_add_inode(ip);
return;
}
lock_buffer(bh);
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, &gfs2_databuf_lops);
lock_buffer(bh);
gfs2_log_lock(sdp);
}
gfs2_assert(sdp, bd->bd_gl == gl);
tr->tr_touched = 1;
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++;
sdp->sd_log_num_databuf++;
list_add_tail(&bd->bd_list, &sdp->sd_log_le_databuf);
}
gfs2_log_unlock(sdp);
unlock_buffer(bh);
}
static void meta_lo_add(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
{
struct gfs2_meta_header *mh;
struct gfs2_trans *tr;
tr = current->journal_info;
tr->tr_touched = 1;
if (!list_empty(&bd->bd_list))
return;
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))) {
printk(KERN_ERR
"Attempting to add uninitialised block to journal (inplace block=%lld)\n",
(unsigned long long)bd->bd_bh->b_blocknr);
BUG();
}
gfs2_pin(sdp, bd->bd_bh);
mh->__pad0 = cpu_to_be64(0);
mh->mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
sdp->sd_log_num_buf++;
list_add(&bd->bd_list, &sdp->sd_log_le_buf);
tr->tr_num_buf_new++;
}
void gfs2_trans_add_meta(struct gfs2_glock *gl, struct buffer_head *bh)
{
struct gfs2_sbd *sdp = gl->gl_sbd;
struct gfs2_bufdata *bd;
lock_buffer(bh);
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, &gfs2_buf_lops);
unlock_page(bh->b_page);
lock_buffer(bh);
gfs2_log_lock(sdp);
}
gfs2_assert(sdp, bd->bd_gl == gl);
meta_lo_add(sdp, bd);
gfs2_log_unlock(sdp);
unlock_buffer(bh);
}
void gfs2_trans_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
{
struct gfs2_glock *gl = bd->bd_gl;
struct gfs2_trans *tr = current->journal_info;
BUG_ON(!list_empty(&bd->bd_list));
BUG_ON(!list_empty(&bd->bd_ail_st_list));
BUG_ON(!list_empty(&bd->bd_ail_gl_list));
bd->bd_ops = &gfs2_revoke_lops;
tr->tr_touched = 1;
tr->tr_num_revoke++;
sdp->sd_log_num_revoke++;
atomic_inc(&gl->gl_revokes);
set_bit(GLF_LFLUSH, &gl->gl_flags);
list_add(&bd->bd_list, &sdp->sd_log_le_revoke);
}
void gfs2_trans_add_unrevoke(struct gfs2_sbd *sdp, u64 blkno, unsigned int len)
{
struct gfs2_bufdata *bd, *tmp;
struct gfs2_trans *tr = current->journal_info;
unsigned int n = len;
gfs2_log_lock(sdp);
list_for_each_entry_safe(bd, tmp, &sdp->sd_log_le_revoke, 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--;
kmem_cache_free(gfs2_bufdata_cachep, bd);
tr->tr_num_revoke_rm++;
if (--n == 0)
break;
}
}
gfs2_log_unlock(sdp);
}
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