linux/fs/gfs2/trans.c
Steven Whitehouse d8348de06f GFS2: Fix deadlock on journal flush
This patch fixes a deadlock when the journal is flushed and there
are dirty inodes other than the one which caused the journal flush.
Originally the journal flushing code was trying to obtain the
transaction glock while running the flush code for an inode glock.
We no longer require the transaction glock at this point in time
since we know that any attempt to get the transaction glock from
another node will result in a journal flush. So if we are flushing
the journal, we can be sure that the transaction lock is still
cached from when the transaction was started.

By inlining a version of gfs2_trans_begin() (minus the bit which
gets the transaction glock) we can avoid the deadlock problems
caused if there is a demote request queued up on the transaction
glock.

In addition I've also moved the umount rwsem so that it covers
the glock workqueue, since it all demotions are done by this
workqueue now. That fixes a bug on umount which I came across
while fixing the original problem.

Reported-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-03-24 11:21:18 +00:00

178 lines
4.2 KiB
C

/*
* 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 "log.h"
#include "lops.h"
#include "meta_io.h"
#include "trans.h"
#include "util.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);
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));
INIT_LIST_HEAD(&tr->tr_list_buf);
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;
if (!test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags)) {
tr->tr_t_gh.gh_flags |= GL_NOCACHE;
error = -EROFS;
goto fail_gunlock;
}
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:
gfs2_holder_uninit(&tr->tr_t_gh);
kfree(tr);
return error;
}
void gfs2_trans_end(struct gfs2_sbd *sdp)
{
struct gfs2_trans *tr = current->journal_info;
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);
}
return;
}
if (gfs2_assert_withdraw(sdp, tr->tr_num_buf <= tr->tr_blocks)) {
fs_err(sdp, "tr_num_buf = %u, tr_blocks = %u ",
tr->tr_num_buf, tr->tr_blocks);
print_symbol(KERN_WARNING "GFS2: Transaction created at: %s\n", tr->tr_ip);
}
if (gfs2_assert_withdraw(sdp, tr->tr_num_revoke <= tr->tr_revokes)) {
fs_err(sdp, "tr_num_revoke = %u, tr_revokes = %u ",
tr->tr_num_revoke, tr->tr_revokes);
print_symbol(KERN_WARNING "GFS2: Transaction created at: %s\n", tr->tr_ip);
}
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);
}
/**
* gfs2_trans_add_bh - Add a to-be-modified buffer to the current transaction
* @gl: the glock the buffer belongs to
* @bh: The buffer to add
* @meta: True in the case of adding metadata
*
*/
void gfs2_trans_add_bh(struct gfs2_glock *gl, struct buffer_head *bh, int meta)
{
struct gfs2_sbd *sdp = gl->gl_sbd;
struct gfs2_bufdata *bd;
bd = bh->b_private;
if (bd)
gfs2_assert(sdp, bd->bd_gl == gl);
else {
gfs2_attach_bufdata(gl, bh, meta);
bd = bh->b_private;
}
lops_add(sdp, &bd->bd_le);
}
void gfs2_trans_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
{
BUG_ON(!list_empty(&bd->bd_le.le_list));
BUG_ON(!list_empty(&bd->bd_ail_st_list));
BUG_ON(!list_empty(&bd->bd_ail_gl_list));
lops_init_le(&bd->bd_le, &gfs2_revoke_lops);
lops_add(sdp, &bd->bd_le);
}
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_le.le_list) {
if ((bd->bd_blkno >= blkno) && (bd->bd_blkno < (blkno + len))) {
list_del_init(&bd->bd_le.le_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);
}
void gfs2_trans_add_rg(struct gfs2_rgrpd *rgd)
{
lops_add(rgd->rd_sbd, &rgd->rd_le);
}