Hi,
On Sat, 11 Sep 2010 15:40:12 -0400, Matteo Frigo wrote:
> To check whether a file system is mounted, nilfs-tune was comparing
> the device name to the contents of /etc/mtab. This check does not
> detect a mounted file system when the device has multiple names, which
> is a common case when using LVM. (LVM creates symbolic links from
> /dev/mapper/vg-lv to /dev/dm-X.)
>
> This patch, borrowed from the analogous check in e2fsprogs, compares
> the device number (field st_rdev of struct stat) rather than the
> device name.
>
> Signed-off-by: Matteo Frigo <athena@xxxxxxxx>
The patch looks sane except for the checkpatch warnings below:
> WARNING: line over 80 characters
> #526: FILE: nilfs-tune.c:526:
> + fprintf(stderr, "ERROR: %s is currently mounted. Aborting execution.\n"
>
> WARNING: line over 80 characters
> #529: FILE: nilfs-tune.c:529:
> + "You can use the \"-f\" option to force this operation.\n",
>
> total: 0 errors, 2 warnings, 535 lines checked
I will adopt your patch with minor amendment.
Thank you.
Ryusuke Konishi
> ---
> configure.ac | 3 +-
> sbin/nilfs-tune/nilfs-tune.c | 69 +++++++++++++++++++++++++++++++----------
> 2 files changed, 54 insertions(+), 18 deletions(-)
>
> diff --git a/configure.ac b/configure.ac
> index af75142..963e2fd 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -37,7 +37,8 @@ AC_HEADER_STDC
> AC_HEADER_SYS_WAIT
> AC_CHECK_HEADERS([fcntl.h libintl.h limits.h locale.h mntent.h paths.h \
> stdlib.h string.h strings.h sys/ioctl.h sys/mount.h \
> - sys/time.h syslog.h unistd.h linux/types.h grp.h pwd.h])
> + sys/time.h syslog.h unistd.h linux/types.h grp.h pwd.h \
> + mntent.h])
>
> # Checks for typedefs, structures, and compiler characteristics.
> AC_C_CONST
> diff --git a/sbin/nilfs-tune/nilfs-tune.c b/sbin/nilfs-tune/nilfs-tune.c
> index 18513f2..5b7f030 100644
> --- a/sbin/nilfs-tune/nilfs-tune.c
> +++ b/sbin/nilfs-tune/nilfs-tune.c
> @@ -58,6 +58,11 @@
> #include <pwd.h>
> #endif /* HAVE_PWD_H */
>
> +#ifdef HAVE_MNTENT_H
> +#include <mntent.h>
> +#endif
> +
> +#include <sys/stat.h>
> #include <ctype.h>
>
> #include <errno.h>
> @@ -444,26 +449,57 @@ int modify_nilfs(char *device, struct nilfs_tune_options *opts)
> return ret;
> }
>
> -/* Code borrowed from nilfs2-util/sbin/mkfs/mkfs.c */
> +/* check_mount() checks whether DEVICE is a mounted file system.
> + Returns 0 if the DEVICE is *not* mounted (which we consider a
> + successful outcome), and -1 if DEVICE is mounted or if the mount
> + status cannot be determined.
> +
> + Derived from e2fsprogs/lib/ext2fs/ismounted.c
> + Copyright (C) 1995,1996,1997,1998,1999,2000 Theodore Ts'o,
> + LGPL v2
> +*/
> static int check_mount(const char *device)
> {
> - FILE *fp;
> - char line[LINE_BUFFER_SIZE];
> -
> - fp = fopen(MOUNTS, "r");
> - if (fp == NULL) {
> + struct mntent *mnt;
> + struct stat st_buf;
> + FILE *f;
> + dev_t file_dev = 0, file_rdev = 0;
> + ino_t file_ino = 0;
> +
> + f = setmntent(MOUNTS, "r");
> + if (f == NULL) {
> fprintf(stderr, "Error: cannot open %s!", MOUNTS);
> - return 1;
> + return -1;
> }
>
> - while (fgets(line, LINE_BUFFER_SIZE, fp) != NULL) {
> - if (strncmp(strtok(line, " "), device, strlen(device)) == 0) {
> - fclose(fp);
> - return 1;
> + if (stat(device, &st_buf) == 0) {
> + if (S_ISBLK(st_buf.st_mode)) {
> + file_rdev = st_buf.st_rdev;
> + } else {
> + file_dev = st_buf.st_dev;
> + file_ino = st_buf.st_ino;
> }
> }
> - fclose(fp);
> - return 0;
> +
> + while ((mnt = getmntent(f)) != NULL) {
> + if (mnt->mnt_fsname[0] != '/')
> + continue;
> + if (strcmp(device, mnt->mnt_fsname) == 0)
> + break;
> + if (stat(mnt->mnt_fsname, &st_buf) == 0) {
> + if (S_ISBLK(st_buf.st_mode)) {
> + if (file_rdev && (file_rdev == st_buf.st_rdev))
> + break;
> + } else {
> + if (file_dev && ((file_dev == st_buf.st_dev) &&
> + (file_ino == st_buf.st_ino)))
> + break;
> + }
> + }
> + }
> +
> + endmntent(f);
> + return (mnt == NULL) ? 0 : -1;
> }
>
> int main(int argc, char *argv[])
> @@ -486,12 +522,11 @@ int main(int argc, char *argv[])
> exit(EXIT_FAILURE);
> }
>
> - if (!opts.force && opts.flags == O_RDWR && check_mount(device)) {
> - fprintf(stderr, "Warning: %s is currently mounted.\n"
> + if (!opts.force && opts.flags == O_RDWR && (check_mount(device) < 0)) {
> + fprintf(stderr, "ERROR: %s is currently mounted. Aborting execution.\n"
> "Running nilfs-tune on a mounted file system "
> "may cause SEVERE damage.\n"
> - "You can force to modify file system by "
> - "\"-f\" option.\n",
> + "You can use the \"-f\" option to force this operation.\n",
> device);
> exit(EXIT_SUCCESS);
> }
> --
> 1.7.1
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