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Commit 5687b578 authored by Artem Bityutskiy's avatar Artem Bityutskiy Committed by Al Viro
Browse files

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: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent b16ca626

fs/hfs/extent.c

+1 −1
Original line number Diff line number Diff line
@@ -432,7 +432,7 @@ int hfs_extend_file(struct inode *inode) 
		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;

fs/hfs/hfs_fs.h

+8 −1
Original line number Diff line number Diff line
@@ -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) ({			\

fs/hfs/inode.c

+4 −7
Original line number Diff line number Diff line
@@ -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)

fs/hfs/super.c

+35 −30
Original line number Diff line number Diff line
@@ -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)) {