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Date:      Fri, 23 Aug 2019 19:40:11 +0000 (UTC)
From:      Konstantin Belousov <kib@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r351435 - in head/sys: kern sys ufs/ffs
Message-ID:  <201908231940.x7NJeBLt016364@repo.freebsd.org>
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Author: kib
Date: Fri Aug 23 19:40:10 2019
New Revision: 351435
URL: https://svnweb.freebsd.org/changeset/base/351435

Log:
  De-commision the MNTK_NOINSMNTQ kernel mount flag.
  
  After all the changes, its dynamic scope is same as for MNTK_UNMOUNT,
  but to allow the syncer vnode to be re-installed on unmount failure.
  But the case of syncer was already handled by using the VV_FORCEINSMQ
  flag for quite some time.
  
  Tested by:	pho
  Sponsored by:	The FreeBSD Foundation
  MFC after:	1 week

Modified:
  head/sys/kern/vfs_mount.c
  head/sys/kern/vfs_subr.c
  head/sys/sys/mount.h
  head/sys/ufs/ffs/ffs_softdep.c

Modified: head/sys/kern/vfs_mount.c
==============================================================================
--- head/sys/kern/vfs_mount.c	Fri Aug 23 18:26:34 2019	(r351434)
+++ head/sys/kern/vfs_mount.c	Fri Aug 23 19:40:10 2019	(r351435)
@@ -1387,14 +1387,13 @@ dounmount(struct mount *mp, int flags, struct thread *
 		dounmount_cleanup(mp, coveredvp, 0);
 		return (EBUSY);
 	}
-	mp->mnt_kern_flag |= MNTK_UNMOUNT | MNTK_NOINSMNTQ;
+	mp->mnt_kern_flag |= MNTK_UNMOUNT;
 	if (flags & MNT_NONBUSY) {
 		MNT_IUNLOCK(mp);
 		error = vfs_check_usecounts(mp);
 		MNT_ILOCK(mp);
 		if (error != 0) {
-			dounmount_cleanup(mp, coveredvp, MNTK_UNMOUNT |
-			    MNTK_NOINSMNTQ);
+			dounmount_cleanup(mp, coveredvp, MNTK_UNMOUNT);
 			return (error);
 		}
 	}
@@ -1456,7 +1455,6 @@ dounmount(struct mount *mp, int flags, struct thread *
 	 */
 	if (error && error != ENXIO) {
 		MNT_ILOCK(mp);
-		mp->mnt_kern_flag &= ~MNTK_NOINSMNTQ;
 		if ((mp->mnt_flag & MNT_RDONLY) == 0) {
 			MNT_IUNLOCK(mp);
 			vfs_allocate_syncvnode(mp);

Modified: head/sys/kern/vfs_subr.c
==============================================================================
--- head/sys/kern/vfs_subr.c	Fri Aug 23 18:26:34 2019	(r351434)
+++ head/sys/kern/vfs_subr.c	Fri Aug 23 19:40:10 2019	(r351435)
@@ -1698,7 +1698,7 @@ insmntque1(struct vnode *vp, struct mount *mp,
 	 */
 	MNT_ILOCK(mp);
 	VI_LOCK(vp);
-	if (((mp->mnt_kern_flag & MNTK_NOINSMNTQ) != 0 &&
+	if (((mp->mnt_kern_flag & MNTK_UNMOUNT) != 0 &&
 	    ((mp->mnt_kern_flag & MNTK_UNMOUNTF) != 0 ||
 	    mp->mnt_nvnodelistsize == 0)) &&
 	    (vp->v_vflag & VV_FORCEINSMQ) == 0) {
@@ -3818,7 +3818,6 @@ DB_SHOW_COMMAND(mount, db_show_mount)
 	MNT_KERN_FLAG(MNTK_UNMOUNTF);
 	MNT_KERN_FLAG(MNTK_ASYNC);
 	MNT_KERN_FLAG(MNTK_SOFTDEP);
-	MNT_KERN_FLAG(MNTK_NOINSMNTQ);
 	MNT_KERN_FLAG(MNTK_DRAINING);
 	MNT_KERN_FLAG(MNTK_REFEXPIRE);
 	MNT_KERN_FLAG(MNTK_EXTENDED_SHARED);

Modified: head/sys/sys/mount.h
==============================================================================
--- head/sys/sys/mount.h	Fri Aug 23 18:26:34 2019	(r351434)
+++ head/sys/sys/mount.h	Fri Aug 23 19:40:10 2019	(r351435)
@@ -368,23 +368,20 @@ void          __mnt_vnode_markerfree_active(struct vno
 /*
  * Internal filesystem control flags stored in mnt_kern_flag.
  *
- * MNTK_UNMOUNT locks the mount entry so that name lookup cannot proceed
- * past the mount point.  This keeps the subtree stable during mounts
- * and unmounts.
+ * MNTK_UNMOUNT locks the mount entry so that name lookup cannot
+ * proceed past the mount point.  This keeps the subtree stable during
+ * mounts and unmounts.  When non-forced unmount flushes all vnodes
+ * from the mp queue, the MNTK_UNMOUNT flag prevents insmntque() from
+ * queueing new vnodes.
  *
  * MNTK_UNMOUNTF permits filesystems to detect a forced unmount while
  * dounmount() is still waiting to lock the mountpoint. This allows
  * the filesystem to cancel operations that might otherwise deadlock
  * with the unmount attempt (used by NFS).
- *
- * MNTK_NOINSMNTQ is strict subset of MNTK_UNMOUNT. They are separated
- * to allow for failed unmount attempt to restore the syncer vnode for
- * the mount.
  */
 #define MNTK_UNMOUNTF	0x00000001	/* forced unmount in progress */
 #define MNTK_ASYNC	0x00000002	/* filtered async flag */
 #define MNTK_SOFTDEP	0x00000004	/* async disabled by softdep */
-#define MNTK_NOINSMNTQ	0x00000008	/* insmntque is not allowed */
 #define	MNTK_DRAINING	0x00000010	/* lock draining is happening */
 #define	MNTK_REFEXPIRE	0x00000020	/* refcount expiring is happening */
 #define MNTK_EXTENDED_SHARED	0x00000040 /* Allow shared locking for more ops */

Modified: head/sys/ufs/ffs/ffs_softdep.c
==============================================================================
--- head/sys/ufs/ffs/ffs_softdep.c	Fri Aug 23 18:26:34 2019	(r351434)
+++ head/sys/ufs/ffs/ffs_softdep.c	Fri Aug 23 19:40:10 2019	(r351435)
@@ -2028,8 +2028,6 @@ retry_flush:
 		if (oldmnt->mnt_kern_flag & MNTK_UNMOUNT) {
 			retry = 0;
 			MNT_ILOCK(oldmnt);
-			KASSERT((oldmnt->mnt_kern_flag & MNTK_NOINSMNTQ) != 0,
-			    ("softdep_flushfiles: !MNTK_NOINSMNTQ"));
 			morework = oldmnt->mnt_nvnodelistsize > 0;
 #ifdef QUOTA
 			ump = VFSTOUFS(oldmnt);

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