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Message-ID: <1341238012.2979.16.camel@sauron.fi.intel.com>
Date: Mon, 02 Jul 2012 17:06:52 +0300
From: Artem Bityutskiy <dedekind1@...il.com>
To: Al Viro <viro@...IV.linux.org.uk>
Cc: Jan Kara <jack@...e.cz>,
Linux FS Maling List <linux-fsdevel@...r.kernel.org>,
Linux Kernel Maling List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 7/7] affs: get rid of affs_sync_super
From: Artem Bityutskiy <artem.bityutskiy@...ux.intel.com>
Date: Tue, 5 Jun 2012 13:30:44 +0300
Subject: [PATCH v2 13/23] affs: get rid of affs_sync_super
This patch makes affs stop using the VFS '->write_super()' method along with
the 's_dirt' superblock flag, because they are on their way out.
The whole "superblock write-out" VFS infrastructure is served by the
'sync_supers()' kernel thread, which wakes up every 5 (by default) seconds and
writes out all dirty superblocks using the '->write_super()' call-back. But the
problem with this thread is that it wastes power by waking up the system every
5 seconds, even if there are no diry superblocks, or there are no client
file-systems which would need this (e.g., btrfs does not use
'->write_super()'). So we want to kill it completely and thus, we need to make
file-systems to stop using the '->write_super()' VFS service, and then remove
it together with the kernel thread.
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@...ux.intel.com>
---
fs/affs/affs.h | 6 ++++++
fs/affs/bitmap.c | 4 ++--
fs/affs/super.c | 48 +++++++++++++++++++++++++++++++++++++-----------
3 files changed, 45 insertions(+), 13 deletions(-)
|This is patch is the same except that it fixes several white-space
|issues. If you plrefer an incremental patch, please, let me know. The
|issues are:
|
|WARNING:SUSPECT_CODE_INDENT: suspect code indent for conditional statements (8, 15)
|#140: FILE: fs/affs/super.c:86:
|+ if (sb->s_flags & MS_RDONLY)
|+ return;
|
|WARNING:SUSPECT_CODE_INDENT: suspect code indent for conditional statements (8, 15)
|#144: FILE: fs/affs/super.c:90:
|+ if (!sbi->work_queued) {
|+ delay = msecs_to_jiffies(dirty_writeback_interval * 10);
diff --git a/fs/affs/affs.h b/fs/affs/affs.h
index 5a726e9..3a130e2 100644
--- a/fs/affs/affs.h
+++ b/fs/affs/affs.h
@@ -3,6 +3,7 @@
#include <linux/buffer_head.h>
#include <linux/amigaffs.h>
#include <linux/mutex.h>
+#include <linux/workqueue.h>
/* AmigaOS allows file names with up to 30 characters length.
* Names longer than that will be silently truncated. If you
@@ -101,6 +102,9 @@ struct affs_sb_info {
char s_volume[32]; /* Volume prefix for absolute symlinks. */
spinlock_t symlink_lock; /* protects the previous two */
struct super_block *sb; /* the VFS superblock object */
+ int work_queued; /* non-zero delayed work is queued */
+ struct delayed_work sb_work; /* superblock flush delayed work */
+ spinlock_t work_lock; /* protects sb_work and work_queued */
};
#define SF_INTL 0x0001 /* International filesystem. */
@@ -121,6 +125,8 @@ static inline struct affs_sb_info *AFFS_SB(struct super_block *sb)
return sb->s_fs_info;
}
+void affs_mark_sb_dirty(struct super_block *sb);
+
/* amigaffs.c */
extern int affs_insert_hash(struct inode *inode, struct buffer_head *bh);
diff --git a/fs/affs/bitmap.c b/fs/affs/bitmap.c
index 3e26271..6e0be43 100644
--- a/fs/affs/bitmap.c
+++ b/fs/affs/bitmap.c
@@ -103,7 +103,7 @@ affs_free_block(struct super_block *sb, u32 block)
*(__be32 *)bh->b_data = cpu_to_be32(tmp - mask);
mark_buffer_dirty(bh);
- sb->s_dirt = 1;
+ affs_mark_sb_dirty(sb);
bm->bm_free++;
mutex_unlock(&sbi->s_bmlock);
@@ -248,7 +248,7 @@ find_bit:
*(__be32 *)bh->b_data = cpu_to_be32(tmp + mask);
mark_buffer_dirty(bh);
- sb->s_dirt = 1;
+ affs_mark_sb_dirty(sb);
mutex_unlock(&sbi->s_bmlock);
diff --git a/fs/affs/super.c b/fs/affs/super.c
index 0496cbb..c70f1e5 100644
--- a/fs/affs/super.c
+++ b/fs/affs/super.c
@@ -17,6 +17,7 @@
#include <linux/magic.h>
#include <linux/sched.h>
#include <linux/slab.h>
+#include <linux/writeback.h>
#include "affs.h"
extern struct timezone sys_tz;
@@ -47,6 +48,7 @@ affs_put_super(struct super_block *sb)
struct affs_sb_info *sbi = AFFS_SB(sb);
pr_debug("AFFS: put_super()\n");
+ cancel_delayed_work_sync(&sbi->sb_work);
kfree(sbi->s_prefix);
affs_free_bitmap(sb);
affs_brelse(sbi->s_root_bh);
@@ -54,23 +56,45 @@ affs_put_super(struct super_block *sb)
sb->s_fs_info = NULL;
}
-static void
-affs_write_super(struct super_block *sb)
-{
- if (!(sb->s_flags & MS_RDONLY))
- affs_commit_super(sb, 1);
- sb->s_dirt = 0;
- pr_debug("AFFS: write_super() at %lu, clean=2\n", get_seconds());
-}
-
static int
affs_sync_fs(struct super_block *sb, int wait)
{
affs_commit_super(sb, wait);
- sb->s_dirt = 0;
return 0;
}
+static void flush_superblock(struct work_struct *work)
+{
+ struct affs_sb_info *sbi;
+ struct super_block *sb;
+
+ sbi = container_of(work, struct affs_sb_info, sb_work.work);
+ sb = sbi->sb;
+
+ spin_lock(&sbi->work_lock);
+ sbi->work_queued = 0;
+ spin_unlock(&sbi->work_lock);
+
+ affs_commit_super(sb, 1);
+}
+
+void affs_mark_sb_dirty(struct super_block *sb)
+{
+ struct affs_sb_info *sbi = AFFS_SB(sb);
+ unsigned long delay;
+
+ if (sb->s_flags & MS_RDONLY)
+ return;
+
+ spin_lock(&sbi->work_lock);
+ if (!sbi->work_queued) {
+ delay = msecs_to_jiffies(dirty_writeback_interval * 10);
+ queue_delayed_work(system_long_wq, &sbi->sb_work, delay);
+ sbi->work_queued = 1;
+ }
+ spin_unlock(&sbi->work_lock);
+}
+
static struct kmem_cache * affs_inode_cachep;
static struct inode *affs_alloc_inode(struct super_block *sb)
@@ -132,7 +156,6 @@ static const struct super_operations affs_sops = {
.write_inode = affs_write_inode,
.evict_inode = affs_evict_inode,
.put_super = affs_put_super,
- .write_super = affs_write_super,
.sync_fs = affs_sync_fs,
.statfs = affs_statfs,
.remount_fs = affs_remount,
@@ -302,6 +325,8 @@ static int affs_fill_super(struct super_block *sb, void *data, int silent)
sbi->sb = sb;
mutex_init(&sbi->s_bmlock);
spin_lock_init(&sbi->symlink_lock);
+ spin_lock_init(&sbi->work_lock);
+ INIT_DELAYED_WORK(&sbi->sb_work, flush_superblock);
if (!parse_options(data,&uid,&gid,&i,&reserved,&root_block,
&blocksize,&sbi->s_prefix,
@@ -526,6 +551,7 @@ affs_remount(struct super_block *sb, int *flags, char *data)
return -EINVAL;
}
+ flush_delayed_work_sync(&sbi->sb_work);
replace_mount_options(sb, new_opts);
sbi->s_flags = mount_flags;
--
1.7.10
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