Commit 1dfa2710 authored by Jiro SEKIBA's avatar Jiro SEKIBA Committed by Ryusuke Konishi
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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: default avatarJiro SEKIBA <jir@unicus.jp>
Signed-off-by: default avatarRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
parent 79efdd94

fs/nilfs2/segment.c

+6 −1
Original line number Diff line number Diff line
@@ -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;

fs/nilfs2/super.c

+1 −45
Original line number Diff line number Diff line
@@ -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 */

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