svn commit: r273967 - head/sys/ufs/ffs

[Konstantin Belousov]

Author: kib
Date: Sun Nov  2 13:14:55 2014
New Revision: 273967
URL: https://svnweb.freebsd.org/changeset/base/273967

Log:
  When non-forced unmount or remount rw->ro is performed, writes on UFS
  are not suspended.  In particular, on the SU-enabled vulumes, there is
  no reason why, between the call to softdep_flushfiles() and
  softdep_waitidle(), SU work items cannot be queued.
  
  Correct the condition to trigger the panic by only checking when
  forced operation is done.  Convert direct panic() call into KASSERT(),
  there is no invalid on-disk data structures directly involved, so
  follow the usual debugging vs. non-debugging approach.
  
  Reported and tested by:	pho
  Reviewed by:	mckusick
  Sponsored by:	The FreeBSD Foundation
  MFC after:	1 week

Modified:
  head/sys/ufs/ffs/ffs_softdep.c

Modified: head/sys/ufs/ffs/ffs_softdep.c
==============================================================================
--- head/sys/ufs/ffs/ffs_softdep.c	Sun Nov  2 13:10:31 2014	(r273966)
+++ head/sys/ufs/ffs/ffs_softdep.c	Sun Nov  2 13:14:55 2014	(r273967)
@@ -735,7 +735,7 @@ static struct malloc_type *memtype[] = {
 static	void check_clear_deps(struct mount *);
 static	void softdep_error(char *, int);
 static	int softdep_process_worklist(struct mount *, int);
-static	int softdep_waitidle(struct mount *);
+static	int softdep_waitidle(struct mount *, int);
 static	void drain_output(struct vnode *);
 static	struct buf *getdirtybuf(struct buf *, struct rwlock *, int);
 static	void clear_remove(struct mount *);
@@ -1911,7 +1911,7 @@ softdep_flushworklist(oldmnt, countp, td
 }
 
 static int
-softdep_waitidle(struct mount *mp)
+softdep_waitidle(struct mount *mp, int flags __unused)
 {
 	struct ufsmount *ump;
 	int error;
@@ -1921,8 +1921,9 @@ softdep_waitidle(struct mount *mp)
 	ACQUIRE_LOCK(ump);
 	for (i = 0; i < 10 && ump->softdep_deps; i++) {
 		ump->softdep_req = 1;
-		if (ump->softdep_on_worklist)
-			panic("softdep_waitidle: work added after flush.");
+		KASSERT((flags & FORCECLOSE) == 0 ||
+		    ump->softdep_on_worklist == 0,
+		    ("softdep_waitidle: work added after flush"));
 		msleep(&ump->softdep_deps, LOCK_PTR(ump), PVM, "softdeps", 1);
 	}
 	ump->softdep_req = 0;
@@ -1990,7 +1991,7 @@ retry_flush:
 		error = EBUSY;
 	}
 	if (!error)
-		error = softdep_waitidle(oldmnt);
+		error = softdep_waitidle(oldmnt, flags);
 	if (!error) {
 		if (oldmnt->mnt_kern_flag & MNTK_UNMOUNT) {
 			retry = 0;