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Message-ID: <1341238538.2979.21.camel@sauron.fi.intel.com>
Date: Mon, 02 Jul 2012 17:15:38 +0300
From: Artem Bityutskiy <dedekind1@...il.com>
To: Al Viro <viro@...IV.linux.org.uk>,
Andrew Morton <akpm@...ux-foundation.org>
Cc: Linux FS Maling List <linux-fsdevel@...r.kernel.org>,
Linux Kernel Maling List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 6/6] hfs: get rid of hfs_sync_super
From: Artem Bityutskiy <artem.bityutskiy@...ux.intel.com>
Date: Tue, 12 Jun 2012 10:40:56 +0300
Subject: [PATCH 19/23] hfs: get rid of hfs_sync_super
This patch makes hfs 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.
Tested using fsstress from the LTP project.
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@...ux.intel.com>
---
fs/hfs/extent.c | 2 +-
fs/hfs/hfs_fs.h | 9 +++++++-
fs/hfs/inode.c | 11 ++++------
fs/hfs/mdb.c | 2 ++
fs/hfs/super.c | 65 ++++++++++++++++++++++++++++++-------------------------
5 files changed, 50 insertions(+), 39 deletions(-)
|This is patch is the same except that it fixes several white-space
|issues. If you prefer an incremental patch, please, let me know. The
|issues are:
|
|WARNING:SUSPECT_CODE_INDENT: suspect code indent for conditional statements (8, 15)
|#213: FILE: fs/hfs/super.c:73:
|+ if (sb->s_flags & MS_RDONLY)
|+ return;
|
|WARNING:SUSPECT_CODE_INDENT: suspect code indent for conditional statements (8, 15)
|#217: FILE: fs/hfs/super.c:77:
|+ if (!sbi->work_queued) {
|+ delay = msecs_to_jiffies(dirty_writeback_interval * 10);
diff --git a/fs/hfs/extent.c b/fs/hfs/extent.c
index 2c16316..a67955a 100644
--- a/fs/hfs/extent.c
+++ b/fs/hfs/extent.c
@@ -432,7 +432,7 @@ out:
if (inode->i_ino < HFS_FIRSTUSER_CNID)
set_bit(HFS_FLG_ALT_MDB_DIRTY, &HFS_SB(sb)->flags);
set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
- sb->s_dirt = 1;
+ hfs_mark_mdb_dirty(sb);
}
return res;
diff --git a/fs/hfs/hfs_fs.h b/fs/hfs/hfs_fs.h
index 3515612..8275175 100644
--- a/fs/hfs/hfs_fs.h
+++ b/fs/hfs/hfs_fs.h
@@ -14,6 +14,7 @@
#include <linux/mutex.h>
#include <linux/buffer_head.h>
#include <linux/fs.h>
+#include <linux/workqueue.h>
#include <asm/byteorder.h>
#include <asm/uaccess.h>
@@ -143,6 +144,9 @@ struct hfs_sb_info {
u16 blockoffset;
int fs_div;
struct super_block *sb;
+ int work_queued; /* non-zero delayed work is queued */
+ struct delayed_work mdb_work; /* MDB flush delayed work */
+ spinlock_t work_lock; /* protects mdb_work and work_queued */
};
#define HFS_FLG_BITMAP_DIRTY 0
@@ -222,6 +226,9 @@ extern int hfs_compare_dentry(const struct dentry *parent,
extern void hfs_asc2mac(struct super_block *, struct hfs_name *, struct qstr *);
extern int hfs_mac2asc(struct super_block *, char *, const struct hfs_name *);
+/* super.c */
+extern void hfs_mark_mdb_dirty(struct super_block *sb);
+
extern struct timezone sys_tz;
/*
@@ -249,7 +256,7 @@ static inline const char *hfs_mdb_name(struct super_block *sb)
static inline void hfs_bitmap_dirty(struct super_block *sb)
{
set_bit(HFS_FLG_BITMAP_DIRTY, &HFS_SB(sb)->flags);
- sb->s_dirt = 1;
+ hfs_mark_mdb_dirty(sb);
}
#define sb_bread512(sb, sec, data) ({ \
diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c
index 629eba4..cb78138 100644
--- a/fs/hfs/inode.c
+++ b/fs/hfs/inode.c
@@ -220,7 +220,7 @@ struct inode *hfs_new_inode(struct inode *dir, struct qstr *name, umode_t mode)
insert_inode_hash(inode);
mark_inode_dirty(inode);
set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
- sb->s_dirt = 1;
+ hfs_mark_mdb_dirty(sb);
return inode;
}
@@ -235,7 +235,7 @@ void hfs_delete_inode(struct inode *inode)
if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
HFS_SB(sb)->root_dirs--;
set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
- sb->s_dirt = 1;
+ hfs_mark_mdb_dirty(sb);
return;
}
HFS_SB(sb)->file_count--;
@@ -248,7 +248,7 @@ void hfs_delete_inode(struct inode *inode)
}
}
set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
- sb->s_dirt = 1;
+ hfs_mark_mdb_dirty(sb);
}
void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext,
@@ -644,10 +644,7 @@ static int hfs_file_fsync(struct file *filp, loff_t start, loff_t end,
/* sync the superblock to buffers */
sb = inode->i_sb;
- if (sb->s_dirt) {
- sb->s_dirt = 0;
- hfs_mdb_commit(sb);
- }
+ flush_delayed_work_sync(&HFS_SB(sb)->mdb_work);
/* .. finally sync the buffers to disk */
err = sync_blockdev(sb->s_bdev);
if (!ret)
diff --git a/fs/hfs/mdb.c b/fs/hfs/mdb.c
index 5fd51a5..a5cd355 100644
--- a/fs/hfs/mdb.c
+++ b/fs/hfs/mdb.c
@@ -263,6 +263,8 @@ void hfs_mdb_commit(struct super_block *sb)
if (sb->s_flags & MS_RDONLY)
return;
+ cancel_delayed_work(&HFS_SB(sb)->mdb_work);
+
lock_buffer(HFS_SB(sb)->mdb_bh);
if (test_and_clear_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags)) {
/* These parameters may have been modified, so write them back */
diff --git a/fs/hfs/super.c b/fs/hfs/super.c
index 99c6239..14528ee 100644
--- a/fs/hfs/super.c
+++ b/fs/hfs/super.c
@@ -29,38 +29,9 @@ static struct kmem_cache *hfs_inode_cachep;
MODULE_LICENSE("GPL");
-/*
- * hfs_write_super()
- *
- * Description:
- * This function is called by the VFS only. When the filesystem
- * is mounted r/w it updates the MDB on disk.
- * Input Variable(s):
- * struct super_block *sb: Pointer to the hfs superblock
- * Output Variable(s):
- * NONE
- * Returns:
- * void
- * Preconditions:
- * 'sb' points to a "valid" (struct super_block).
- * Postconditions:
- * The MDB is marked 'unsuccessfully unmounted' by clearing bit 8 of drAtrb
- * (hfs_put_super() must set this flag!). Some MDB fields are updated
- * and the MDB buffer is written to disk by calling hfs_mdb_commit().
- */
-static void hfs_write_super(struct super_block *sb)
-{
- sb->s_dirt = 0;
-
- /* sync everything to the buffers */
- hfs_mdb_commit(sb);
-}
-
static int hfs_sync_fs(struct super_block *sb, int wait)
{
hfs_mdb_commit(sb);
- sb->s_dirt = 0;
-
return 0;
}
@@ -73,11 +44,44 @@ static int hfs_sync_fs(struct super_block *sb, int wait)
*/
static void hfs_put_super(struct super_block *sb)
{
+ cancel_delayed_work_sync(&HFS_SB(sb)->mdb_work);
hfs_mdb_close(sb);
/* release the MDB's resources */
hfs_mdb_put(sb);
}
+static void flush_mdb(struct work_struct *work)
+{
+ struct hfs_sb_info *sbi;
+ struct super_block *sb;
+
+ sbi = container_of(work, struct hfs_sb_info, mdb_work.work);
+ sb = sbi->sb;
+
+ spin_lock(&sbi->work_lock);
+ sbi->work_queued = 0;
+ spin_unlock(&sbi->work_lock);
+
+ hfs_mdb_commit(sb);
+}
+
+void hfs_mark_mdb_dirty(struct super_block *sb)
+{
+ struct hfs_sb_info *sbi = HFS_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->mdb_work, delay);
+ sbi->work_queued = 1;
+ }
+ spin_unlock(&sbi->work_lock);
+}
+
/*
* hfs_statfs()
*
@@ -177,7 +181,6 @@ static const struct super_operations hfs_super_operations = {
.write_inode = hfs_write_inode,
.evict_inode = hfs_evict_inode,
.put_super = hfs_put_super,
- .write_super = hfs_write_super,
.sync_fs = hfs_sync_fs,
.statfs = hfs_statfs,
.remount_fs = hfs_remount,
@@ -382,6 +385,8 @@ static int hfs_fill_super(struct super_block *sb, void *data, int silent)
sbi->sb = sb;
sb->s_fs_info = sbi;
+ spin_lock_init(&sbi->work_lock);
+ INIT_DELAYED_WORK(&sbi->mdb_work, flush_mdb);
res = -EINVAL;
if (!parse_options((char *)data, sbi)) {
--
1.7.10
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