On Tue, Aug 29, 2006 at 01:03:51PM -0400, Theodore Tso wrote:
> On Tue, Aug 29, 2006 at 11:09:35AM -0400, Sev Binello wrote:
> > From a strictly practical and immediate stand point,
> > what is the best way to handle this situation if it should occur again in
> > the near future ?
>
> Without any kernel patches, the best thing to do is, (a) don't restore
> the path to the device, (b) unmount the filesystem, (c) Compile the
> enclosed flushb program (also found in the e2fsprogs sources, but not
> compiled by most or all distributions), and run it: "flushb
> /dev/hdXX", and only after completing all of these steps, you can
> restore the path and do fsck of the filesystem if you are feeling
> sufficiently paranoid, and then remount it.
option (d) run blockdev --flushbufs /dev/hdXX
Ted, you may drop flushb. blockdev from util-linux can do it.
- coywolf
>
> I wish I could offer you something better, but that's what we have at
> the moment.
>
> - Ted
>
> /*
> * flushb.c --- This routine flushes the disk buffers for a disk
> *
> * Copyright 1997, 2000, by Theodore Ts'o.
> *
> * WARNING: use of flushb on some older 2.2 kernels on a heavily loaded
> * system will corrupt filesystems. This program is not really useful
> * beyond for benchmarking scripts.
> *
> * %Begin-Header%
> * This file may be redistributed under the terms of the GNU Public
> * License.
> * %End-Header%
> */
>
> #include <stdio.h>
> #include <string.h>
> #include <unistd.h>
> #include <stdlib.h>
> #include <fcntl.h>
> #include <sys/ioctl.h>
> #include <sys/mount.h>
>
> /* For Linux, define BLKFLSBUF if necessary */
> #if (!defined(BLKFLSBUF) && defined(__linux__))
> #define BLKFLSBUF _IO(0x12,97) /* flush buffer cache */
> #endif
>
> const char *progname;
>
> static void usage(void)
> {
> fprintf(stderr, "Usage: %s disk\n", progname);
> exit(1);
> }
>
> int main(int argc, char **argv)
> {
> int fd;
>
> progname = argv[0];
> if (argc != 2)
> usage();
>
> fd = open(argv[1], O_RDONLY, 0);
> if (fd < 0) {
> perror("open");
> exit(1);
> }
> /*
> * Note: to reread the partition table, use the ioctl
> * BLKRRPART instead of BLKFSLBUF.
> */
> if (ioctl(fd, BLKFLSBUF, 0) < 0) {
> perror("ioctl BLKFLSBUF");
> exit(1);
> }
> return 0;
> }
--
Coywolf Qi Hunt
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