linux/fs/gfs2/lock_dlm.c
Steven Whitehouse 009d851837 GFS2: Metadata address space clean up
Since the start of GFS2, an "extra" inode has been used to store
the metadata belonging to each inode. The only reason for using
this inode was to have an extra address space, the other fields
were unused. This means that the memory usage was rather inefficient.

The reason for keeping each inode's metadata in a separate address
space is that when glocks are requested on remote nodes, we need to
be able to efficiently locate the data and metadata which relating
to that glock (inode) in order to sync or sync and invalidate it
(depending on the remotely requested lock mode).

This patch adds a new type of glock, which has in addition to
its normal fields, has an address space. This applies to all
inode and rgrp glocks (but to no other glock types which remain
as before). As a result, we no longer need to have the second
inode.

This results in three major improvements:
 1. A saving of approx 25% of memory used in caching inodes
 2. A removal of the circular dependency between inodes and glocks
 3. No confusion between "normal" and "metadata" inodes in super.c

Although the first of these is the more immediately apparent, the
second is just as important as it now enables a number of clean
ups at umount time. Those will be the subject of future patches.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2010-03-01 14:07:37 +00:00

250 lines
5.4 KiB
C

/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2009 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/fs.h>
#include <linux/dlm.h>
#include <linux/types.h>
#include <linux/gfs2_ondisk.h>
#include "incore.h"
#include "glock.h"
#include "util.h"
static void gdlm_ast(void *arg)
{
struct gfs2_glock *gl = arg;
unsigned ret = gl->gl_state;
struct gfs2_sbd *sdp = gl->gl_sbd;
BUG_ON(gl->gl_lksb.sb_flags & DLM_SBF_DEMOTED);
if (gl->gl_lksb.sb_flags & DLM_SBF_VALNOTVALID)
memset(gl->gl_lvb, 0, GDLM_LVB_SIZE);
switch (gl->gl_lksb.sb_status) {
case -DLM_EUNLOCK: /* Unlocked, so glock can be freed */
if (gl->gl_ops->go_flags & GLOF_ASPACE)
kmem_cache_free(gfs2_glock_aspace_cachep, gl);
else
kmem_cache_free(gfs2_glock_cachep, gl);
if (atomic_dec_and_test(&sdp->sd_glock_disposal))
wake_up(&sdp->sd_glock_wait);
return;
case -DLM_ECANCEL: /* Cancel while getting lock */
ret |= LM_OUT_CANCELED;
goto out;
case -EAGAIN: /* Try lock fails */
goto out;
case -EINVAL: /* Invalid */
case -ENOMEM: /* Out of memory */
ret |= LM_OUT_ERROR;
goto out;
case 0: /* Success */
break;
default: /* Something unexpected */
BUG();
}
ret = gl->gl_req;
if (gl->gl_lksb.sb_flags & DLM_SBF_ALTMODE) {
if (gl->gl_req == LM_ST_SHARED)
ret = LM_ST_DEFERRED;
else if (gl->gl_req == LM_ST_DEFERRED)
ret = LM_ST_SHARED;
else
BUG();
}
set_bit(GLF_INITIAL, &gl->gl_flags);
gfs2_glock_complete(gl, ret);
return;
out:
if (!test_bit(GLF_INITIAL, &gl->gl_flags))
gl->gl_lksb.sb_lkid = 0;
gfs2_glock_complete(gl, ret);
}
static void gdlm_bast(void *arg, int mode)
{
struct gfs2_glock *gl = arg;
switch (mode) {
case DLM_LOCK_EX:
gfs2_glock_cb(gl, LM_ST_UNLOCKED);
break;
case DLM_LOCK_CW:
gfs2_glock_cb(gl, LM_ST_DEFERRED);
break;
case DLM_LOCK_PR:
gfs2_glock_cb(gl, LM_ST_SHARED);
break;
default:
printk(KERN_ERR "unknown bast mode %d", mode);
BUG();
}
}
/* convert gfs lock-state to dlm lock-mode */
static int make_mode(const unsigned int lmstate)
{
switch (lmstate) {
case LM_ST_UNLOCKED:
return DLM_LOCK_NL;
case LM_ST_EXCLUSIVE:
return DLM_LOCK_EX;
case LM_ST_DEFERRED:
return DLM_LOCK_CW;
case LM_ST_SHARED:
return DLM_LOCK_PR;
}
printk(KERN_ERR "unknown LM state %d", lmstate);
BUG();
return -1;
}
static u32 make_flags(const u32 lkid, const unsigned int gfs_flags,
const int req)
{
u32 lkf = 0;
if (gfs_flags & LM_FLAG_TRY)
lkf |= DLM_LKF_NOQUEUE;
if (gfs_flags & LM_FLAG_TRY_1CB) {
lkf |= DLM_LKF_NOQUEUE;
lkf |= DLM_LKF_NOQUEUEBAST;
}
if (gfs_flags & LM_FLAG_PRIORITY) {
lkf |= DLM_LKF_NOORDER;
lkf |= DLM_LKF_HEADQUE;
}
if (gfs_flags & LM_FLAG_ANY) {
if (req == DLM_LOCK_PR)
lkf |= DLM_LKF_ALTCW;
else if (req == DLM_LOCK_CW)
lkf |= DLM_LKF_ALTPR;
else
BUG();
}
if (lkid != 0)
lkf |= DLM_LKF_CONVERT;
lkf |= DLM_LKF_VALBLK;
return lkf;
}
static unsigned int gdlm_lock(struct gfs2_glock *gl,
unsigned int req_state, unsigned int flags)
{
struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
int error;
int req;
u32 lkf;
gl->gl_req = req_state;
req = make_mode(req_state);
lkf = make_flags(gl->gl_lksb.sb_lkid, flags, req);
/*
* Submit the actual lock request.
*/
error = dlm_lock(ls->ls_dlm, req, &gl->gl_lksb, lkf, gl->gl_strname,
GDLM_STRNAME_BYTES - 1, 0, gdlm_ast, gl, gdlm_bast);
if (error == -EAGAIN)
return 0;
if (error)
return LM_OUT_ERROR;
return LM_OUT_ASYNC;
}
static void gdlm_put_lock(struct kmem_cache *cachep, struct gfs2_glock *gl)
{
struct gfs2_sbd *sdp = gl->gl_sbd;
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
int error;
if (gl->gl_lksb.sb_lkid == 0) {
kmem_cache_free(cachep, gl);
if (atomic_dec_and_test(&sdp->sd_glock_disposal))
wake_up(&sdp->sd_glock_wait);
return;
}
error = dlm_unlock(ls->ls_dlm, gl->gl_lksb.sb_lkid, DLM_LKF_VALBLK,
NULL, gl);
if (error) {
printk(KERN_ERR "gdlm_unlock %x,%llx err=%d\n",
gl->gl_name.ln_type,
(unsigned long long)gl->gl_name.ln_number, error);
return;
}
}
static void gdlm_cancel(struct gfs2_glock *gl)
{
struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
dlm_unlock(ls->ls_dlm, gl->gl_lksb.sb_lkid, DLM_LKF_CANCEL, NULL, gl);
}
static int gdlm_mount(struct gfs2_sbd *sdp, const char *fsname)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
int error;
if (fsname == NULL) {
fs_info(sdp, "no fsname found\n");
return -EINVAL;
}
error = dlm_new_lockspace(fsname, strlen(fsname), &ls->ls_dlm,
DLM_LSFL_FS | DLM_LSFL_NEWEXCL |
(ls->ls_nodir ? DLM_LSFL_NODIR : 0),
GDLM_LVB_SIZE);
if (error)
printk(KERN_ERR "dlm_new_lockspace error %d", error);
return error;
}
static void gdlm_unmount(struct gfs2_sbd *sdp)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
if (ls->ls_dlm) {
dlm_release_lockspace(ls->ls_dlm, 2);
ls->ls_dlm = NULL;
}
}
static const match_table_t dlm_tokens = {
{ Opt_jid, "jid=%d"},
{ Opt_id, "id=%d"},
{ Opt_first, "first=%d"},
{ Opt_nodir, "nodir=%d"},
{ Opt_err, NULL },
};
const struct lm_lockops gfs2_dlm_ops = {
.lm_proto_name = "lock_dlm",
.lm_mount = gdlm_mount,
.lm_unmount = gdlm_unmount,
.lm_put_lock = gdlm_put_lock,
.lm_lock = gdlm_lock,
.lm_cancel = gdlm_cancel,
.lm_tokens = &dlm_tokens,
};