Introduce the option VFS_ALLOW_NONMPSAFE and turn it on by default on

all the architectures.
The option allows to mount non-MPSAFE filesystem. Without it, the
kernel will refuse to mount a non-MPSAFE filesytem.

This patch is part of the effort of killing non-MPSAFE filesystems
from the tree.

No MFC is expected for this patch.

Tested by:	gianni
Reviewed by:	kib

12 files changed, 47 insertions, 0 deletions

diff --git a/UPDATING b/UPDATING
index 1189f4c..dc17383 100644
--- a/UPDATING
+++ b/UPDATING
@@ -22,6 +22,12 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 10.x IS SLOW:
 	machines to maximize performance.  (To disable malloc debugging, run
 	ln -s aj /etc/malloc.conf.)
 
+20111108:
+	The option VFS_ALLOW_NONMPSAFE option has been added in order to
+	explicitely support non-MPSAFE filesystems.
+	It is on by default for all supported platform at this present
+	time.
+
 20111101:
 	The broken amd(4) driver has been replaced with esp(4) in the amd64,
 	i386 and pc98 GENERIC kernel configuration files.
diff --git a/sys/amd64/conf/DEFAULTS b/sys/amd64/conf/DEFAULTS
index 2c221cb..e39a9e4 100644
--- a/sys/amd64/conf/DEFAULTS
+++ b/sys/amd64/conf/DEFAULTS
@@ -22,3 +22,6 @@ options 	GEOM_PART_EBR_COMPAT
 options 	GEOM_PART_MBR
 
 options 	NEW_PCIB
+
+# Allow mounting non-MPSAFE filesystems
+options		VFS_ALLOW_NONMPSAFE
diff --git a/sys/arm/conf/DEFAULTS b/sys/arm/conf/DEFAULTS
index 591a0a1..3546d4e 100644
--- a/sys/arm/conf/DEFAULTS
+++ b/sys/arm/conf/DEFAULTS
@@ -9,3 +9,5 @@ device		mem
 
 options 	GEOM_PART_BSD
 options 	GEOM_PART_MBR
+
+options		VFS_ALLOW_NONMPSAFE
diff --git a/sys/conf/NOTES b/sys/conf/NOTES
index 882d49c..a3d33c2a 100644
--- a/sys/conf/NOTES
+++ b/sys/conf/NOTES
@@ -1104,6 +1104,9 @@ options 	XFS
 # unsuitable for inclusion on machines with untrusted local users.
 options 	VFS_AIO
 
+# Enable mounting of non-MPSAFE filesystems.
+options 	VFS_ALLOW_NONMPSAFE
+
 # Cryptographically secure random number generator; /dev/random
 device		random
 
diff --git a/sys/conf/options b/sys/conf/options
index 6ddecb8..61078bb 100644
--- a/sys/conf/options
+++ b/sys/conf/options
@@ -185,6 +185,7 @@ SYSVSHM		opt_sysvipc.h
 SW_WATCHDOG	opt_watchdog.h
 TURNSTILE_PROFILING
 VFS_AIO
+VFS_ALLOW_NONMPSAFE
 VERBOSE_SYSINIT	opt_global.h
 WLCACHE		opt_wavelan.h
 WLDEBUG		opt_wavelan.h
diff --git a/sys/i386/conf/DEFAULTS b/sys/i386/conf/DEFAULTS
index 78d807c..1c5cd96 100644
--- a/sys/i386/conf/DEFAULTS
+++ b/sys/i386/conf/DEFAULTS
@@ -30,3 +30,6 @@ options 	NATIVE
 device		atpic
 
 options 	NEW_PCIB
+
+# Allow mounting non-MPSAFE filesystems
+options		VFS_ALLOW_NONMPSAFE
diff --git a/sys/ia64/conf/DEFAULTS b/sys/ia64/conf/DEFAULTS
index a3e10d6..e31e26b 100644
--- a/sys/ia64/conf/DEFAULTS
+++ b/sys/ia64/conf/DEFAULTS
@@ -20,3 +20,6 @@ options 	GEOM_PART_GPT
 options 	GEOM_PART_MBR
 
 options 	NEW_PCIB
+
+# Allow mounting non-MPSAFE filesystems
+options		VFS_ALLOW_NONMPSAFE
diff --git a/sys/kern/vfs_mount.c b/sys/kern/vfs_mount.c
index 545a183..873f425 100644
--- a/sys/kern/vfs_mount.c
+++ b/sys/kern/vfs_mount.c
@@ -37,6 +37,8 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include "opt_vfs_allow_nonmpsafe.h"
+
 #include <sys/param.h>
 #include <sys/conf.h>
 #include <sys/fcntl.h>
@@ -798,6 +800,14 @@ vfs_domount_first(
 	 * get.  No freeing of cn_pnbuf.
 	 */
 	error = VFS_MOUNT(mp);
+#ifndef VFS_ALLOW_NONMPSAFE
+	if (error == 0 && VFS_NEEDSGIANT(mp)) {
+		(void)VFS_UNMOUNT(mp, fsflags);
+		error = ENXIO;
+		printf("%s: Mounting non-MPSAFE fs (%s) is disabled\n",
+		    __func__, mp->mnt_vfc->vfc_name);
+	}
+#endif
 	if (error != 0) {
 		vfs_unbusy(mp);
 		vfs_mount_destroy(mp);
@@ -807,6 +817,11 @@ vfs_domount_first(
 		vrele(vp);
 		return (error);
 	}
+#ifdef VFS_ALLOW_NONMPSAFE
+	if (VFS_NEEDSGIANT(mp))
+		printf("%s: Mounting non-MPSAFE fs (%s) is deprecated\n",
+		    __func__, mp->mnt_vfc->vfc_name);
+#endif
 
 	if (mp->mnt_opt != NULL)
 		vfs_freeopts(mp->mnt_opt);
diff --git a/sys/mips/conf/DEFAULTS b/sys/mips/conf/DEFAULTS
index f09ef54..f015e89 100644
--- a/sys/mips/conf/DEFAULTS
+++ b/sys/mips/conf/DEFAULTS
@@ -9,3 +9,5 @@ device		uart_ns8250
 
 options 	GEOM_PART_BSD
 options 	GEOM_PART_MBR
+
+options		VFS_ALLOW_NONMPSAFE
diff --git a/sys/pc98/conf/DEFAULTS b/sys/pc98/conf/DEFAULTS
index 6c8b561..342a604 100644
--- a/sys/pc98/conf/DEFAULTS
+++ b/sys/pc98/conf/DEFAULTS
@@ -29,3 +29,6 @@ options 	GEOM_PART_PC98
 device		atpic
 
 options 	NEW_PCIB
+
+# Allow mounting non-MPSAFE filesystems
+options		VFS_ALLOW_NONMPSAFE
diff --git a/sys/powerpc/conf/DEFAULTS b/sys/powerpc/conf/DEFAULTS
index 658c221..54d1940 100644
--- a/sys/powerpc/conf/DEFAULTS
+++ b/sys/powerpc/conf/DEFAULTS
@@ -12,3 +12,6 @@ device		uart_z8530
 
 options 	GEOM_PART_APM
 options 	GEOM_PART_MBR
+
+# Allow mounting non-MPSAFE filesystems
+options		VFS_ALLOW_NONMPSAFE
diff --git a/sys/sparc64/conf/DEFAULTS b/sys/sparc64/conf/DEFAULTS
index c99480c..f1305a8 100644
--- a/sys/sparc64/conf/DEFAULTS
+++ b/sys/sparc64/conf/DEFAULTS
@@ -21,3 +21,6 @@ options 	GEOM_PART_VTOC8
 options 	SUNKBD_EMULATE_ATKBD
 
 options 	NEW_PCIB
+
+# Allow mounting non-MPSAFE filesystems
+options		VFS_ALLOW_NONMPSAFE