Date: Sat, 24 Jul 1999 11:52:07 -0700 (PDT) From: bob@pmr.com To: freebsd-gnats-submit@freebsd.org Subject: bin/12789: Confusing error msg when dumping a filesystem by mount point thats not in /etc/fstab Message-ID: <19990724185207.7764614DE6@hub.freebsd.org>
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>Number: 12789
>Category: bin
>Synopsis: Confusing error msg when dumping a filesystem by mount point thats not in /etc/fstab
>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: Sat Jul 24 12:00:01 PDT 1999
>Closed-Date:
>Last-Modified:
>Originator: Bob Willcox
>Release: 3.2-stable
>Organization:
Power Micro Research
>Environment:
FreeBSD luke.pmr.com 3.2-STABLE FreeBSD 3.2-STABLE #7: Tue Jul 20 12:00:05 CDT 1999 bob@luke.pmr.com:/usr/src/sys/compile/LUKE i386
>Description:
When dumping a filesystem by specifying its mount point (rather than its
special file name) if there is no entry in fstab for the filesystem dump
fails with what can be a misleading error message.
For example if I dump /bsd (which has no fstab entry I get):
bob@luke-pf /usr/src/sbin/dump> dump -0ab 32 -f /dev/null /bsd
DUMP: Date of this level 0 dump: Sat Jul 24 13:21:19 1999
DUMP: Date of last level 0 dump: the epoch
DUMP: Dumping /bsd to /dev/null
DUMP: bad sblock magic number
What has happened here is that dump, because it did not find an entry
for /bsd in /etc/fstab has opened the directory /bsd and tried to dump
it (and, of course, failed since it has no superblock).
>How-To-Repeat:
Run dump against a mounted filesystem that has no entry in /etc/fstab
and specifify its mount point rather than the special file path.
>Fix:
I have implemented a simple additional check to see that the open file
(should be the filesystem) isn't a directory (as it will be in this case).
If it is a directory, the changed code prints a warning message to assist
the user in diagnosing what he has done wrong.
The output from dump will now look like this:
bob@luke-pf /usr/src/sbin/dump> /usr/obj/usr/src/sbin/dump/dump -0ab 32 -f /d >
DUMP: Date of this level 0 dump: Sat Jul 24 13:47:39 1999
DUMP: Date of last level 0 dump: the epoch
DUMP: Dumping /bsd to /dev/null
DUMP: WARNING: /bsd will be processed as a directory, not a filesystem
DUMP: bad sblock magic number
DUMP: The ENTIRE dump is aborted.
There are, no doubt, other and likely better ways to solve this problem
but this worked for me (next time I won't spend so much time tracking
down what's really wrong).
Here is a patch for the change should you be interested:
Index: src/sbin/dump/main.c
===================================================================
RCS file: /usr/cvs/FreeBSD/src/sbin/dump/main.c,v
retrieving revision 1.18
diff -u -r1.18 main.c
--- main.c 1998/09/16 20:52:12 1.18
+++ main.c 1999/07/24 18:47:32
@@ -68,6 +68,7 @@
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
+#include <sys/stat.h>
#include "dump.h"
#include "pathnames.h"
@@ -104,6 +105,7 @@
register int ch;
int i, anydirskipped, bflag = 0, Tflag = 0, honorlevel = 1;
ino_t maxino;
+ struct stat sb;
spcl.c_date = 0;
(void)time((time_t *)&spcl.c_date);
@@ -327,6 +333,11 @@
msg("Cannot open %s\n", disk);
exit(X_STARTUP);
}
+ if (fstat(diskfd, &sb))
+ quit("unable to fstat filesystem");
+ if (S_ISDIR(sb.st_mode))
+ msg("WARNING: %s will be processed as a directory, not a filesystem\n",
+ disk);
sync();
sblock = (struct fs *)sblock_buf;
bread(SBOFF, (char *) sblock, SBSIZE);
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