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nilfs2: stop using periodic write_super callback 

This removes nilfs_write_super and commit super block in nilfs
internal thread, instead of periodic write_super callback.

VFS layer calls ->write_super callback periodically.  However,
it looks like that calling back is ommited when disk I/O is busy.
And when cleanerd (nilfs GC) is runnig, disk I/O tend to be busy thus
nilfs superblock is not synchronized as nilfs designed.

To avoid it, syncing superblock by nilfs thread instead of pdflush.

Signed-off-by: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This commit is contained in:
Jiro SEKIBA 2009-07-23 01:33:49 +09:00 committed by Ryusuke Konishi
parent 79efdd9411
commit 1dfa27105a
2 changed files with 7 additions and 46 deletions
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7
fs/nilfs2/segment.c
View File

@ -2501,7 +2501,8 @@ static int nilfs_segctor_construct(struct nilfs_sc_info *sci,
if (test_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags) &&
nilfs_discontinued(nilfs)) {
down_write(&nilfs->ns_sem);
req->sb_err = nilfs_commit_super(sbi, 0);
req->sb_err = nilfs_commit_super(sbi,
nilfs_altsb_need_update(nilfs));
up_write(&nilfs->ns_sem);
}
}
@ -2689,6 +2690,7 @@ static int nilfs_segctor_thread(void *arg)
} else {
DEFINE_WAIT(wait);
int should_sleep = 1;
struct the_nilfs *nilfs;
prepare_to_wait(&sci->sc_wait_daemon, &wait,
TASK_INTERRUPTIBLE);
@ -2709,6 +2711,9 @@ static int nilfs_segctor_thread(void *arg)
finish_wait(&sci->sc_wait_daemon, &wait);
timeout = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
time_after_eq(jiffies, sci->sc_timer->expires));
nilfs = sci->sc_sbi->s_nilfs;
if (sci->sc_super->s_dirt && nilfs_sb_need_update(nilfs))
set_nilfs_discontinued(nilfs);
}
goto loop;

46
fs/nilfs2/super.c
View File

@ -67,7 +67,6 @@ MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
"(NILFS)");
MODULE_LICENSE("GPL");
static void nilfs_write_super(struct super_block *sb);
static int nilfs_remount(struct super_block *sb, int *flags, char *data);
/**
@ -335,49 +334,6 @@ static void nilfs_put_super(struct super_block *sb)
unlock_kernel();
}
/**
* nilfs_write_super - write super block(s) of NILFS
* @sb: super_block
*
* nilfs_write_super() gets a fs-dependent lock, writes super block(s), and
* clears s_dirt. This function is called in the section protected by
* lock_super().
*
* The s_dirt flag is managed by each filesystem and we protect it by ns_sem
* of the struct the_nilfs. Lock order must be as follows:
*
* 1. lock_super()
* 2. down_write(&nilfs->ns_sem)
*
* Inside NILFS, locking ns_sem is enough to protect s_dirt and the buffer
* of the super block (nilfs->ns_sbp[]).
*
* In most cases, VFS functions call lock_super() before calling these
* methods. So we must be careful not to bring on deadlocks when using
* lock_super(); see generic_shutdown_super(), write_super(), and so on.
*
* Note that order of lock_kernel() and lock_super() depends on contexts
* of VFS. We should also note that lock_kernel() can be used in its
* protective section and only the outermost one has an effect.
*/
static void nilfs_write_super(struct super_block *sb)
{
struct nilfs_sb_info *sbi = NILFS_SB(sb);
struct the_nilfs *nilfs = sbi->s_nilfs;
down_write(&nilfs->ns_sem);
if (!(sb->s_flags & MS_RDONLY)) {
if (!nilfs_discontinued(nilfs) &&
!nilfs_sb_need_update(nilfs)) {
up_write(&nilfs->ns_sem);
return;
}
nilfs_commit_super(sbi, nilfs_altsb_need_update(nilfs));
}
sb->s_dirt = 0;
up_write(&nilfs->ns_sem);
}
static int nilfs_sync_fs(struct super_block *sb, int wait)
{
struct nilfs_sb_info *sbi = NILFS_SB(sb);
@ -558,7 +514,7 @@ static struct super_operations nilfs_sops = {
/* .drop_inode = nilfs_drop_inode, */
.delete_inode = nilfs_delete_inode,
.put_super = nilfs_put_super,
.write_super = nilfs_write_super,
/* .write_super = nilfs_write_super, */
.sync_fs = nilfs_sync_fs,
/* .write_super_lockfs */
/* .unlockfs */