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linux/fs/gfs2/ops_super.c
Steven Whitehouse 719ee34467 GFS2: high time to take some time over atime 
Until now, we've used the same scheme as GFS1 for atime. This has failed
since atime is a per vfsmnt flag, not a per fs flag and as such the
"noatime" flag was not getting passed down to the filesystems. This
patch removes all the "special casing" around atime updates and we
simply use the VFS's atime code.

The net result is that GFS2 will now support all the same atime related
mount options of any other filesystem on a per-vfsmnt basis. We do lose
the "lazy atime" updates, but we gain "relatime". We could add lazy
atime to the VFS at a later date, if there is a requirement for that
variant still - I suspect relatime will be enough.

Also we lose about 100 lines of code after this patch has been applied,
and I have a suspicion that it will speed things up a bit, even when
atime is "on". So it seems like a nice clean up as well.

From a user perspective, everything stays the same except the loss of
the per-fs atime quantum tweekable (ought to be per-vfsmnt at the very
least, and to be honest I don't think anybody ever used it) and that a
number of options which were ignored before now work correctly.

Please let me know if you've got any comments. I'm pushing this out
early so that you can all see what my plans are.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-09-18 13:53:59 +01:00

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/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2008 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/statfs.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include <linux/kthread.h>
#include <linux/delay.h>
#include <linux/gfs2_ondisk.h>
#include <linux/crc32.h>
#include <linux/lm_interface.h>
#include <linux/time.h>
#include "gfs2.h"
#include "incore.h"
#include "glock.h"
#include "inode.h"
#include "log.h"
#include "mount.h"
#include "ops_super.h"
#include "quota.h"
#include "recovery.h"
#include "rgrp.h"
#include "super.h"
#include "sys.h"
#include "util.h"
#include "trans.h"
#include "dir.h"
#include "eattr.h"
#include "bmap.h"
#include "meta_io.h"
/**
* gfs2_write_inode - Make sure the inode is stable on the disk
* @inode: The inode
* @sync: synchronous write flag
*
* Returns: errno
*/
static int gfs2_write_inode(struct inode *inode, int sync)
{
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
struct gfs2_holder gh;
struct buffer_head *bh;
struct timespec atime;
struct gfs2_dinode *di;
int ret = 0;
/* Check this is a "normal" inode, etc */
if (!test_bit(GIF_USER, &ip->i_flags) ||
(current->flags & PF_MEMALLOC))
return 0;
ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
if (ret)
goto do_flush;
ret = gfs2_trans_begin(sdp, RES_DINODE, 0);
if (ret)
goto do_unlock;
ret = gfs2_meta_inode_buffer(ip, &bh);
if (ret == 0) {
di = (struct gfs2_dinode *)bh->b_data;
atime.tv_sec = be64_to_cpu(di->di_atime);
atime.tv_nsec = be32_to_cpu(di->di_atime_nsec);
if (timespec_compare(&inode->i_atime, &atime) > 0) {
gfs2_trans_add_bh(ip->i_gl, bh, 1);
gfs2_dinode_out(ip, bh->b_data);
}
brelse(bh);
}
gfs2_trans_end(sdp);
do_unlock:
gfs2_glock_dq_uninit(&gh);
do_flush:
if (sync != 0)
gfs2_log_flush(GFS2_SB(inode), ip->i_gl);
return ret;
}
/**
* gfs2_make_fs_ro - Turn a Read-Write FS into a Read-Only one
* @sdp: the filesystem
*
* Returns: errno
*/
static int gfs2_make_fs_ro(struct gfs2_sbd *sdp)
{
struct gfs2_holder t_gh;
int error;
gfs2_quota_sync(sdp);
gfs2_statfs_sync(sdp);
error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_SHARED, GL_NOCACHE,
&t_gh);
if (error && !test_bit(SDF_SHUTDOWN, &sdp->sd_flags))
return error;
gfs2_meta_syncfs(sdp);
gfs2_log_shutdown(sdp);
clear_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
if (t_gh.gh_gl)
gfs2_glock_dq_uninit(&t_gh);
gfs2_quota_cleanup(sdp);
return error;
}
/**
* gfs2_put_super - Unmount the filesystem
* @sb: The VFS superblock
*
*/
static void gfs2_put_super(struct super_block *sb)
{
struct gfs2_sbd *sdp = sb->s_fs_info;
int error;
/* Unfreeze the filesystem, if we need to */
mutex_lock(&sdp->sd_freeze_lock);
if (sdp->sd_freeze_count)
gfs2_glock_dq_uninit(&sdp->sd_freeze_gh);
mutex_unlock(&sdp->sd_freeze_lock);
kthread_stop(sdp->sd_quotad_process);
kthread_stop(sdp->sd_logd_process);
kthread_stop(sdp->sd_recoverd_process);
while (sdp->sd_glockd_num--)
kthread_stop(sdp->sd_glockd_process[sdp->sd_glockd_num]);
if (!(sb->s_flags & MS_RDONLY)) {
error = gfs2_make_fs_ro(sdp);
if (error)
gfs2_io_error(sdp);
}
/* At this point, we're through modifying the disk */
/* Release stuff */
iput(sdp->sd_jindex);
iput(sdp->sd_inum_inode);
iput(sdp->sd_statfs_inode);
iput(sdp->sd_rindex);
iput(sdp->sd_quota_inode);
gfs2_glock_put(sdp->sd_rename_gl);
gfs2_glock_put(sdp->sd_trans_gl);
if (!sdp->sd_args.ar_spectator) {
gfs2_glock_dq_uninit(&sdp->sd_journal_gh);
gfs2_glock_dq_uninit(&sdp->sd_jinode_gh);
gfs2_glock_dq_uninit(&sdp->sd_ir_gh);
gfs2_glock_dq_uninit(&sdp->sd_sc_gh);
gfs2_glock_dq_uninit(&sdp->sd_qc_gh);
iput(sdp->sd_ir_inode);
iput(sdp->sd_sc_inode);
iput(sdp->sd_qc_inode);
}
gfs2_glock_dq_uninit(&sdp->sd_live_gh);
gfs2_clear_rgrpd(sdp);
gfs2_jindex_free(sdp);
/* Take apart glock structures and buffer lists */
gfs2_gl_hash_clear(sdp);
/* Unmount the locking protocol */
gfs2_lm_unmount(sdp);
/* At this point, we're through participating in the lockspace */
gfs2_sys_fs_del(sdp);
kfree(sdp);
}
/**
* gfs2_write_super
* @sb: the superblock
*
*/
static void gfs2_write_super(struct super_block *sb)
{
sb->s_dirt = 0;
}
/**
* gfs2_sync_fs - sync the filesystem
* @sb: the superblock
*
* Flushes the log to disk.
*/
static int gfs2_sync_fs(struct super_block *sb, int wait)
{
sb->s_dirt = 0;
if (wait && sb->s_fs_info)
gfs2_log_flush(sb->s_fs_info, NULL);
return 0;
}
/**
* gfs2_write_super_lockfs - prevent further writes to the filesystem
* @sb: the VFS structure for the filesystem
*
*/
static void gfs2_write_super_lockfs(struct super_block *sb)
{
struct gfs2_sbd *sdp = sb->s_fs_info;
int error;
if (test_bit(SDF_SHUTDOWN, &sdp->sd_flags))
return;
for (;;) {
error = gfs2_freeze_fs(sdp);
if (!error)
break;
switch (error) {
case -EBUSY:
fs_err(sdp, "waiting for recovery before freeze\n");
break;
default:
fs_err(sdp, "error freezing FS: %d\n", error);
break;
}
fs_err(sdp, "retrying...\n");
msleep(1000);
}
}
/**
* gfs2_unlockfs - reallow writes to the filesystem
* @sb: the VFS structure for the filesystem
*
*/
static void gfs2_unlockfs(struct super_block *sb)
{
gfs2_unfreeze_fs(sb->s_fs_info);
}
/**
* gfs2_statfs - Gather and return stats about the filesystem
* @sb: The superblock
* @statfsbuf: The buffer
*
* Returns: 0 on success or error code
*/
static int gfs2_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct super_block *sb = dentry->d_inode->i_sb;
struct gfs2_sbd *sdp = sb->s_fs_info;
struct gfs2_statfs_change_host sc;
int error;
if (gfs2_tune_get(sdp, gt_statfs_slow))
error = gfs2_statfs_slow(sdp, &sc);
else
error = gfs2_statfs_i(sdp, &sc);
if (error)
return error;
buf->f_type = GFS2_MAGIC;
buf->f_bsize = sdp->sd_sb.sb_bsize;
buf->f_blocks = sc.sc_total;
buf->f_bfree = sc.sc_free;
buf->f_bavail = sc.sc_free;
buf->f_files = sc.sc_dinodes + sc.sc_free;
buf->f_ffree = sc.sc_free;
buf->f_namelen = GFS2_FNAMESIZE;
return 0;
}
/**
* gfs2_remount_fs - called when the FS is remounted
* @sb: the filesystem
* @flags: the remount flags
* @data: extra data passed in (not used right now)
*
* Returns: errno
*/
static int gfs2_remount_fs(struct super_block *sb, int *flags, char *data)
{
struct gfs2_sbd *sdp = sb->s_fs_info;
int error;
error = gfs2_mount_args(sdp, data, 1);
if (error)
return error;
if (sdp->sd_args.ar_spectator)
*flags |= MS_RDONLY;
else {
if (*flags & MS_RDONLY) {
if (!(sb->s_flags & MS_RDONLY))
error = gfs2_make_fs_ro(sdp);
} else if (!(*flags & MS_RDONLY) &&
(sb->s_flags & MS_RDONLY)) {
error = gfs2_make_fs_rw(sdp);
}
}
return error;
}
/**
* gfs2_drop_inode - Drop an inode (test for remote unlink)
* @inode: The inode to drop
*
* If we've received a callback on an iopen lock then its because a
* remote node tried to deallocate the inode but failed due to this node
* still having the inode open. Here we mark the link count zero
* since we know that it must have reached zero if the GLF_DEMOTE flag
* is set on the iopen glock. If we didn't do a disk read since the
* remote node removed the final link then we might otherwise miss
* this event. This check ensures that this node will deallocate the
* inode's blocks, or alternatively pass the baton on to another
* node for later deallocation.
*/
static void gfs2_drop_inode(struct inode *inode)
{
struct gfs2_inode *ip = GFS2_I(inode);
if (test_bit(GIF_USER, &ip->i_flags) && inode->i_nlink) {
struct gfs2_glock *gl = ip->i_iopen_gh.gh_gl;
if (gl && test_bit(GLF_DEMOTE, &gl->gl_flags))
clear_nlink(inode);
}
generic_drop_inode(inode);
}
/**
* gfs2_clear_inode - Deallocate an inode when VFS is done with it
* @inode: The VFS inode
*
*/
static void gfs2_clear_inode(struct inode *inode)
{
struct gfs2_inode *ip = GFS2_I(inode);
/* This tells us its a "real" inode and not one which only
* serves to contain an address space (see rgrp.c, meta_io.c)
* which therefore doesn't have its own glocks.
*/
if (test_bit(GIF_USER, &ip->i_flags)) {
ip->i_gl->gl_object = NULL;
gfs2_glock_schedule_for_reclaim(ip->i_gl);
gfs2_glock_put(ip->i_gl);
ip->i_gl = NULL;
if (ip->i_iopen_gh.gh_gl) {
ip->i_iopen_gh.gh_gl->gl_object = NULL;
gfs2_glock_dq_uninit(&ip->i_iopen_gh);
}
}
}
static int is_ancestor(const struct dentry *d1, const struct dentry *d2)
{
do {
if (d1 == d2)
return 1;
d1 = d1->d_parent;
} while (!IS_ROOT(d1));
return 0;
}
/**
* gfs2_show_options - Show mount options for /proc/mounts
* @s: seq_file structure
* @mnt: vfsmount
*
* Returns: 0 on success or error code
*/
static int gfs2_show_options(struct seq_file *s, struct vfsmount *mnt)
{
struct gfs2_sbd *sdp = mnt->mnt_sb->s_fs_info;
struct gfs2_args *args = &sdp->sd_args;
if (is_ancestor(mnt->mnt_root, sdp->sd_master_dir))
seq_printf(s, ",meta");
if (args->ar_lockproto[0])
seq_printf(s, ",lockproto=%s", args->ar_lockproto);
if (args->ar_locktable[0])
seq_printf(s, ",locktable=%s", args->ar_locktable);
if (args->ar_hostdata[0])
seq_printf(s, ",hostdata=%s", args->ar_hostdata);
if (args->ar_spectator)
seq_printf(s, ",spectator");
if (args->ar_ignore_local_fs)
seq_printf(s, ",ignore_local_fs");
if (args->ar_localflocks)
seq_printf(s, ",localflocks");
if (args->ar_localcaching)
seq_printf(s, ",localcaching");
if (args->ar_debug)
seq_printf(s, ",debug");
if (args->ar_upgrade)
seq_printf(s, ",upgrade");
if (args->ar_num_glockd != GFS2_GLOCKD_DEFAULT)
seq_printf(s, ",num_glockd=%u", args->ar_num_glockd);
if (args->ar_posix_acl)
seq_printf(s, ",acl");
if (args->ar_quota != GFS2_QUOTA_DEFAULT) {
char *state;
switch (args->ar_quota) {
case GFS2_QUOTA_OFF:
state = "off";
break;
case GFS2_QUOTA_ACCOUNT:
state = "account";
break;
case GFS2_QUOTA_ON:
state = "on";
break;
default:
state = "unknown";
break;
}
seq_printf(s, ",quota=%s", state);
}
if (args->ar_suiddir)
seq_printf(s, ",suiddir");
if (args->ar_data != GFS2_DATA_DEFAULT) {
char *state;
switch (args->ar_data) {
case GFS2_DATA_WRITEBACK:
state = "writeback";
break;
case GFS2_DATA_ORDERED:
state = "ordered";
break;
default:
state = "unknown";
break;
}
seq_printf(s, ",data=%s", state);
}
return 0;
}
/*
* We have to (at the moment) hold the inodes main lock to cover
* the gap between unlocking the shared lock on the iopen lock and
* taking the exclusive lock. I'd rather do a shared -> exclusive
* conversion on the iopen lock, but we can change that later. This
* is safe, just less efficient.
*/
static void gfs2_delete_inode(struct inode *inode)
{
struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_holder gh;
int error;
if (!test_bit(GIF_USER, &ip->i_flags))
goto out;
error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
if (unlikely(error)) {
gfs2_glock_dq_uninit(&ip->i_iopen_gh);
goto out;
}
gfs2_glock_dq_wait(&ip->i_iopen_gh);
gfs2_holder_reinit(LM_ST_EXCLUSIVE, LM_FLAG_TRY_1CB | GL_NOCACHE, &ip->i_iopen_gh);
error = gfs2_glock_nq(&ip->i_iopen_gh);
if (error)
goto out_uninit;
if (S_ISDIR(inode->i_mode) &&
(ip->i_di.di_flags & GFS2_DIF_EXHASH)) {
error = gfs2_dir_exhash_dealloc(ip);
if (error)
goto out_unlock;
}
if (ip->i_di.di_eattr) {
error = gfs2_ea_dealloc(ip);
if (error)
goto out_unlock;
}
if (!gfs2_is_stuffed(ip)) {
error = gfs2_file_dealloc(ip);
if (error)
goto out_unlock;
}
error = gfs2_dinode_dealloc(ip);
if (error)
goto out_unlock;
error = gfs2_trans_begin(sdp, 0, sdp->sd_jdesc->jd_blocks);
if (error)
goto out_unlock;
/* Needs to be done before glock release & also in a transaction */
truncate_inode_pages(&inode->i_data, 0);
gfs2_trans_end(sdp);
out_unlock:
gfs2_glock_dq(&ip->i_iopen_gh);
out_uninit:
gfs2_holder_uninit(&ip->i_iopen_gh);
gfs2_glock_dq_uninit(&gh);
if (error && error != GLR_TRYFAILED)
fs_warn(sdp, "gfs2_delete_inode: %d\n", error);
out:
truncate_inode_pages(&inode->i_data, 0);
clear_inode(inode);
}
static struct inode *gfs2_alloc_inode(struct super_block *sb)
{
struct gfs2_inode *ip;
ip = kmem_cache_alloc(gfs2_inode_cachep, GFP_KERNEL);
if (ip) {
ip->i_flags = 0;
ip->i_gl = NULL;
}
return &ip->i_inode;
}
static void gfs2_destroy_inode(struct inode *inode)
{
kmem_cache_free(gfs2_inode_cachep, inode);
}
const struct super_operations gfs2_super_ops = {
.alloc_inode = gfs2_alloc_inode,
.destroy_inode = gfs2_destroy_inode,
.write_inode = gfs2_write_inode,
.delete_inode = gfs2_delete_inode,
.put_super = gfs2_put_super,
.write_super = gfs2_write_super,
.sync_fs = gfs2_sync_fs,
.write_super_lockfs = gfs2_write_super_lockfs,
.unlockfs = gfs2_unlockfs,
.statfs = gfs2_statfs,
.remount_fs = gfs2_remount_fs,
.clear_inode = gfs2_clear_inode,
.drop_inode = gfs2_drop_inode,
.show_options = gfs2_show_options,
};
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