From 38ddb5725bd450537fe84c21d7ab4c03b6114b1e Mon Sep 17 00:00:00 2001
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Fri, 9 Mar 2012 00:12:05 +0000
Subject: [PATCH] Decomission mnt_noasync. Introduce MNTK_NOASYNC mnt_kern_flag
 which allows a filesystem to request VFS to not allow MNTK_ASYNC.

MFC after:	1 week
---
 sys/kern/vfs_mount.c      | 9 ++++++---
 sys/kern/vfs_subr.c       | 2 +-
 sys/sys/mount.h           | 2 +-
 sys/ufs/ffs/ffs_softdep.c | 3 +--
 4 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/sys/kern/vfs_mount.c b/sys/kern/vfs_mount.c
index ddc17cc326ea..93387cad51a8 100644
--- a/sys/kern/vfs_mount.c
+++ b/sys/kern/vfs_mount.c
@@ -851,7 +851,8 @@ vfs_domount_first(
 	mp->mnt_optnew = NULL;
 
 	MNT_ILOCK(mp);
-	if ((mp->mnt_flag & MNT_ASYNC) != 0 && mp->mnt_noasync == 0)
+	if ((mp->mnt_flag & MNT_ASYNC) != 0 &&
+	    (mp->mnt_kern_flag & MNTK_NOASYNC) == 0)
 		mp->mnt_kern_flag |= MNTK_ASYNC;
 	else
 		mp->mnt_kern_flag &= ~MNTK_ASYNC;
@@ -991,7 +992,8 @@ vfs_domount_update(
 		 */
 		mp->mnt_flag = (mp->mnt_flag & MNT_QUOTA) | (flag & ~MNT_QUOTA);
 	}
-	if ((mp->mnt_flag & MNT_ASYNC) != 0 && mp->mnt_noasync == 0)
+	if ((mp->mnt_flag & MNT_ASYNC) != 0 &&
+	    (mp->mnt_kern_flag & MNTK_NOASYNC) == 0)
 		mp->mnt_kern_flag |= MNTK_ASYNC;
 	else
 		mp->mnt_kern_flag &= ~MNTK_ASYNC;
@@ -1351,7 +1353,8 @@ dounmount(mp, flags, td)
 		}
 		mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
 		mp->mnt_flag |= async_flag;
-		if ((mp->mnt_flag & MNT_ASYNC) != 0 && mp->mnt_noasync == 0)
+		if ((mp->mnt_flag & MNT_ASYNC) != 0 &&
+		    (mp->mnt_kern_flag & MNTK_NOASYNC) == 0)
 			mp->mnt_kern_flag |= MNTK_ASYNC;
 		if (mp->mnt_kern_flag & MNTK_MWAIT) {
 			mp->mnt_kern_flag &= ~MNTK_MWAIT;
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index 8d3c6aa0674c..753875f301cc 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -2942,6 +2942,7 @@ DB_SHOW_COMMAND(mount, db_show_mount)
 	MNT_KERN_FLAG(MNTK_REFEXPIRE);
 	MNT_KERN_FLAG(MNTK_EXTENDED_SHARED);
 	MNT_KERN_FLAG(MNTK_SHARED_WRITES);
+	MNT_KERN_FLAG(MNTK_NOASYNC);
 	MNT_KERN_FLAG(MNTK_UNMOUNT);
 	MNT_KERN_FLAG(MNTK_MWAIT);
 	MNT_KERN_FLAG(MNTK_SUSPEND);
@@ -2994,7 +2995,6 @@ DB_SHOW_COMMAND(mount, db_show_mount)
 	db_printf("    mnt_gen = %d\n", mp->mnt_gen);
 	db_printf("    mnt_nvnodelistsize = %d\n", mp->mnt_nvnodelistsize);
 	db_printf("    mnt_writeopcount = %d\n", mp->mnt_writeopcount);
-	db_printf("    mnt_noasync = %u\n", mp->mnt_noasync);
 	db_printf("    mnt_maxsymlinklen = %d\n", mp->mnt_maxsymlinklen);
 	db_printf("    mnt_iosize_max = %d\n", mp->mnt_iosize_max);
 	db_printf("    mnt_hashseed = %u\n", mp->mnt_hashseed);
diff --git a/sys/sys/mount.h b/sys/sys/mount.h
index f68a046ba8a2..2b6041e94aaf 100644
--- a/sys/sys/mount.h
+++ b/sys/sys/mount.h
@@ -167,7 +167,6 @@ struct mount {
 	int		mnt_writeopcount;	/* (i) write syscalls pending */
 	int		mnt_kern_flag;		/* (i) kernel only flags */
 	uint64_t	mnt_flag;		/* (i) flags shared with user */
-	u_int		mnt_noasync;		/* (i) # noasync overrides */
 	struct vfsoptlist *mnt_opt;		/* current mount options */
 	struct vfsoptlist *mnt_optnew;		/* new options passed to fs */
 	int		mnt_maxsymlinklen;	/* max size of short symlink */
@@ -325,6 +324,7 @@ void          __mnt_vnode_markerfree(struct vnode **mvp, struct mount *mp);
 #define	MNTK_REFEXPIRE	0x00000020	/* refcount expiring is happening */
 #define MNTK_EXTENDED_SHARED	0x00000040 /* Allow shared locking for more ops */
 #define	MNTK_SHARED_WRITES	0x00000080 /* Allow shared locking for writes */
+#define MNTK_NOASYNC	0x00800000	/* disable async */
 #define MNTK_UNMOUNT	0x01000000	/* unmount in progress */
 #define	MNTK_MWAIT	0x02000000	/* waiting for unmount to finish */
 #define	MNTK_SUSPEND	0x08000000	/* request write suspension */
diff --git a/sys/ufs/ffs/ffs_softdep.c b/sys/ufs/ffs/ffs_softdep.c
index debb8389e80a..67ef6f4b53a1 100644
--- a/sys/ufs/ffs/ffs_softdep.c
+++ b/sys/ufs/ffs/ffs_softdep.c
@@ -2368,8 +2368,7 @@ softdep_mount(devvp, mp, fs, cred)
 	mp->mnt_flag = (mp->mnt_flag & ~MNT_ASYNC) | MNT_SOFTDEP;
 	if ((mp->mnt_kern_flag & MNTK_SOFTDEP) == 0) {
 		mp->mnt_kern_flag = (mp->mnt_kern_flag & ~MNTK_ASYNC) | 
-			MNTK_SOFTDEP;
-		mp->mnt_noasync++;
+			MNTK_SOFTDEP | MNTK_NOASYNC;
 	}
 	MNT_IUNLOCK(mp);
 	ump = VFSTOUFS(mp);