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Date:      Wed, 20 Mar 2019 23:11:05 +0000 (UTC)
From:      Kirk McKusick <mckusick@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r345352 - head/sys/ufs/ffs
Message-ID:  <201903202311.x2KNB5wX002142@repo.freebsd.org>
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Author: mckusick
Date: Wed Mar 20 23:11:05 2019
New Revision: 345352
URL: https://svnweb.freebsd.org/changeset/base/345352

Log:
  This is an additional and hopefully final fix for bug report 230962.
  This bug was introduced with the change to use softdep_bp_to_mp()
  in January 2018 changes -r327723 and -r327821. The softdep_bp_to_mp()
  function failed to include VSOCK as one of the valid cases.
  
  Although local-domain sockets do not allocate blocks in the filesystem,
  they will allocate blocks if they use extended attributes (such as
  ACLs). Thus, softdep_bp_to_mp() needs to return a non-NULL mount
  pointer when presented with a socket vnode so that the soft updates
  write complete will properly process the soft updates structures
  associated with the extended attribute blocks. It was the failure
  to process these soft updates structures, thus leaving them hanging
  off the buffer, which lead to the "panic: softdep_deallocate_dependencies:
  dangling deps" when trying to clean up the buffer after it was written.
  
  PR:           230962
  Reported by:  2t8mr7kx9f@protonmail.com
  Reviewed by:  kib
  Tested by:    Peter Holm
  MFC after:    1 week
  Sponsored by: Netflix

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

Modified: head/sys/ufs/ffs/ffs_softdep.c
==============================================================================
--- head/sys/ufs/ffs/ffs_softdep.c	Wed Mar 20 22:49:41 2019	(r345351)
+++ head/sys/ufs/ffs/ffs_softdep.c	Wed Mar 20 23:11:05 2019	(r345352)
@@ -13970,6 +13970,8 @@ softdep_bp_to_mp(bp)
 	if (LIST_EMPTY(&bp->b_dep))
 		return (NULL);
 	vp = bp->b_vp;
+	KASSERT(vp != NULL,
+	    ("%s, buffer with dependencies lacks vnode", __func__));
 
 	/*
 	 * The ump mount point is stable after we get a correct
@@ -13979,17 +13981,33 @@ softdep_bp_to_mp(bp)
 	 * workitem might be freed while dereferenced.
 	 */
 retry:
-	if (vp->v_type == VCHR) {
+	switch (vp->v_type) {
+	case VCHR:
 		VI_LOCK(vp);
 		mp = vp->v_type == VCHR ? vp->v_rdev->si_mountpt : NULL;
 		VI_UNLOCK(vp);
 		if (mp == NULL)
 			goto retry;
-	} else if (vp->v_type == VREG || vp->v_type == VDIR ||
-	    vp->v_type == VLNK || vp->v_type == VFIFO) {
+		break;
+	case VREG:
+	case VDIR:
+	case VLNK:
+	case VFIFO:
+	case VSOCK:
 		mp = vp->v_mount;
-	} else {
-		return (NULL);
+		break;
+	case VBLK:
+		vn_printf(vp, "softdep_bp_to_mp: unexpected block device\n");
+		/* FALLTHROUGH */
+	case VNON:
+	case VBAD:
+	case VMARKER:
+		mp = NULL;
+		break;
+	default:
+		vn_printf(vp, "unknown vnode type");
+		mp = NULL;
+		break;
 	}
 	return (VFSTOUFS(mp));
 }

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