Date: Fri, 2 Nov 2012 03:59:23 GMT From: Garrett Cooper <yanegomi@gmail.com> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/173278: kern_getfsstat incorrectly assumes that flags is a bitmask Message-ID: <201211020359.qA23xN36092876@red.freebsd.org> Resent-Message-ID: <201211020400.qA24002R062261@freefall.freebsd.org>
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>Number: 173278
>Category: kern
>Synopsis: kern_getfsstat incorrectly assumes that flags is a bitmask
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Nov 02 04:00:00 UTC 2012
>Closed-Date:
>Last-Modified:
>Originator: Garrett Cooper
>Release: 9.1-PRERELEASE
>Organization:
EMC Isilon
>Environment:
FreeBSD forza.west.isilon.com 9.1-PRERELEASE FreeBSD 9.1-PRERELEASE #0 r240770: Thu Sep 20 19:28:45 PDT 2012 gcooper@forza.west.isilon.com:/usr/obj/usr/src/sys/FORZA amd64
>Description:
kern_getfsstat incorrectly assumes that flags is a bitmask, when in fact the values that can be passed as flags should be mutually exclusive (from sys/sys/mount.h):
413 /*
414 * Flags for various system call interfaces.
415 *
416 * waitfor flags to vfs_sync() and getfsstat()
417 */
418 #define MNT_WAIT 1 /* synchronously wait for I/O to complete */
419 #define MNT_NOWAIT 2 /* start all I/O, but do not wait for it */
420 #define MNT_LAZY 3 /* push data not written by filesystem synce r */
421 #define MNT_SUSPEND 4 /* Suspend file system after sync */
..
The following patch should fix kern_getfsstat, but it's untested:
Index: sys/kern/vfs_syscalls.c
===================================================================
--- sys/kern/vfs_syscalls.c (revision 242321)
+++ sys/kern/vfs_syscalls.c (working copy)
@@ -504,8 +504,7 @@ kern_getfsstat(struct thread *td, struct statfs **
* refresh the fsstat cache. MNT_NOWAIT or MNT_LAZY
* overrides MNT_WAIT.
*/
- if (((flags & (MNT_LAZY|MNT_NOWAIT)) == 0 ||
- (flags & MNT_WAIT)) &&
+ if (flags == MNT_WAIT &&
(error = VFS_STATFS(mp, sp))) {
mtx_lock(&mountlist_mtx);
nmp = TAILQ_NEXT(mp, mnt_list);
Noticed by rhestilow <AT> isilon <DON'T-SPAM-ME DOT> com.
>How-To-Repeat:
Call getfsstat with flags == MNT_LAZY.
>Fix:
Patch attached with submission follows:
Index: sys/kern/vfs_syscalls.c
===================================================================
--- sys/kern/vfs_syscalls.c (revision 242321)
+++ sys/kern/vfs_syscalls.c (working copy)
@@ -504,8 +504,7 @@
* refresh the fsstat cache. MNT_NOWAIT or MNT_LAZY
* overrides MNT_WAIT.
*/
- if (((flags & (MNT_LAZY|MNT_NOWAIT)) == 0 ||
- (flags & MNT_WAIT)) &&
+ if (flags == MNT_WAIT &&
(error = VFS_STATFS(mp, sp))) {
mtx_lock(&mountlist_mtx);
nmp = TAILQ_NEXT(mp, mnt_list);
>Release-Note:
>Audit-Trail:
>Unformatted:
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