On Wed, 2006-11-08 at 22:03 -0500, Jeff Moyer wrote:
> Hi, Ian, list,
>
> Here is a patch to consult /proc/mounts instead of /etc/mtab when
> deciding if a path has already been mounted. The problem with using
> /etc/mtab, as you know, is that it sometimes does not get updated. We
> know that /proc/mounts will always be right, so why not use it?
Good for v4 but keep in mind that in v5 /proc/mounts can have a lot of
entries compared to /etc/mtab. The cost of doing this can be quite high.
mount(8) must play well with mtab for v5.
>
> The patch will determine if /proc/mounts is available at run-time, and
> so will continue to work in the event that proc isn't available.
>
> Comments welcome.
>
> -Jeff
>
> diff --git a/daemon/automount.c b/daemon/automount.c
> index c09eaf6..766c472 100644
> --- a/daemon/automount.c
> +++ b/daemon/automount.c
> @@ -333,7 +333,7 @@ static int umount_multi(const char *path
>
> debug("umount_multi: path=%s incl=%d\n", path, incl);
>
> - mntlist = get_mnt_list(_PATH_MOUNTED, path, incl);
> + mntlist = get_mnt_list(path_mounted, path, incl);
>
> if (!mntlist) {
> warn("umount_multi: no mounts found under %s", path);
> @@ -445,7 +445,7 @@ static int mount_autofs(char *path)
> struct stat st;
> int len;
>
> - if ((ap.state != ST_INIT) || is_mounted(_PATH_MOUNTED, path)) {
> + if ((ap.state != ST_INIT) || is_mounted(path_mounted, path)) {
> /* This can happen if an autofs process is already running*/
> error("mount_autofs: already mounted");
> return -1;
> @@ -1844,6 +1844,16 @@ int handle_mounts(char *path)
> return 0;
> }
>
> +void init_path_mounted(void)
> +{
> + struct stat st;
> +
> + if (stat(PROC_MOUNTS, &st) == 0)
> + path_mounted = PROC_MOUNTS;
> + else
> + path_mounted = _PATH_MOUNTED;
> +}
> +
> int main(int argc, char *argv[])
> {
> char *path, *map, *mapfmt;
> @@ -1928,6 +1938,8 @@ int main(int argc, char *argv[])
> if (!dumpmap)
> become_daemon();
>
> + init_path_mounted();
> +
> path = argv[0];
> map = argv[1];
> mapargv = (const char **) &argv[2];
> diff --git a/daemon/spawn.c b/daemon/spawn.c
> index 53887f9..b7e1511 100644
> --- a/daemon/spawn.c
> +++ b/daemon/spawn.c
> @@ -119,7 +119,7 @@ void discard_pending(int sig)
> */
> int signal_children(int sig)
> {
> - struct mnt_list *mnts = get_mnt_list(_PATH_MOUNTED, "/", 0);
> + struct mnt_list *mnts = get_mnt_list(path_mounted, "/", 0);
> struct mnt_list *next;
> pid_t pgrp = getpgrp();
> int ret = -1;
> diff --git a/include/automount.h b/include/automount.h
> index 14ec07b..c5f4707 100644
> --- a/include/automount.h
> +++ b/include/automount.h
> @@ -40,6 +40,7 @@ #endif
> #define AUTOFS_SUPER_MAGIC 0x00000187L
>
> #define DEFAULT_TIMEOUT (5*60) /* 5 minutes */
> +#define PROC_MOUNTS "/proc/mounts"
> #define AUTOFS_LOCK "/var/lock/autofs" /* To serialize access to mount
> */
> #define MOUNTED_LOCK _PATH_MOUNTED "~" /* mounts' lock file */
> #define MTAB_NOTUPDATED 0x1000 /* mtab succeded but
> not updated */
> @@ -121,6 +122,7 @@ struct autofs_point {
> };
>
> extern struct autofs_point ap;
> +const char *path_mounted;
>
> /* Standard function used by daemon or modules */
>
> diff --git a/lib/cache.c b/lib/cache.c
> index 0f71fe2..c774dc0 100644
> --- a/lib/cache.c
> +++ b/lib/cache.c
> @@ -268,7 +268,7 @@ int cache_delete(const char *root, const
> if (!path)
> return CHE_FAIL;
>
> - if (is_mounted(_PATH_MOUNTED, path)) {
> + if (is_mounted(path_mounted, path)) {
> free(path);
> return CHE_FAIL;
> }
> @@ -439,7 +439,7 @@ int cache_ghost(const char *root, int gh
> break;
>
> case LKP_MOUNT:
> - if (!is_mounted(_PATH_MOUNTED, gc.direct_base))
> {
> + if (!is_mounted(path_mounted, gc.direct_base)) {
> debug("cache_ghost: attempting to mount
> map, "
> "key %s",
> gc.direct_base);
> diff --git a/lib/mounts.c b/lib/mounts.c
> index 1e40fc1..1dacf14 100644
> --- a/lib/mounts.c
> +++ b/lib/mounts.c
> @@ -294,7 +294,7 @@ int contained_in_local_fs(const char *pa
> if (!path || !pathlen || pathlen > PATH_MAX)
> return 0;
>
> - mnts = get_mnt_list(_PATH_MOUNTED, "/", 1);
> + mnts = get_mnt_list(path_mounted, "/", 1);
> if (!mnts)
> return 0;
>
> @@ -309,13 +309,15 @@ int contained_in_local_fs(const char *pa
> rv = statfs(this->path, &fs);
> if (rv != -1 && fs.f_type == AUTOFS_SUPER_MAGIC)
> ret = 1;
> + /* What is the below testing? --JEM */
> else if (this->fs_name[0] == '/') {
> if (strlen(this->fs_name) > 1) {
> if (this->fs_name[1] != '/')
> ret = 1;
> } else
> ret = 1;
> - }
> + } else if (!strncmp(this->fs_name, "rootfs", 6))
> + ret = 1;
> break;
> }
> }
> @@ -357,7 +359,7 @@ int allow_owner_mount(const char *path)
> struct mntent ent;
> int ret = 0;
>
> - if (getuid() || is_mounted(_PATH_MOUNTED, path))
> + if (getuid() || is_mounted(path_mounted, path))
> return 0;
>
> if (find_mntent(_PATH_MNTTAB, path, &ent)) {
> diff --git a/modules/mount_autofs.c b/modules/mount_autofs.c
> index f0edb0a..08ae5f1 100644
> --- a/modules/mount_autofs.c
> +++ b/modules/mount_autofs.c
> @@ -71,7 +71,7 @@ int mount_mount(const char *root, const
> debug(MODPREFIX "fullpath=%s what=%s options=%s",
> fullpath, what, options);
>
> - if (is_mounted(_PATH_MOUNTED, fullpath)) {
> + if (is_mounted(path_mounted, fullpath)) {
> error(MODPREFIX
> "warning: about to mount over %s, continuing", fullpath);
> return 0;
> diff --git a/modules/mount_bind.c b/modules/mount_bind.c
> index 20ab7bf..fbf1546 100644
> --- a/modules/mount_bind.c
> +++ b/modules/mount_bind.c
> @@ -121,7 +121,7 @@ int mount_mount(const char *root, const
> if (!status)
> existed = 0;
>
> - if (is_mounted(_PATH_MOUNTED, fullpath)) {
> + if (is_mounted(path_mounted, fullpath)) {
> error(MODPREFIX
> "warning: %s is already mounted", fullpath);
> return 0;
> diff --git a/modules/mount_ext2.c b/modules/mount_ext2.c
> index 38d67bf..b2efb96 100644
> --- a/modules/mount_ext2.c
> +++ b/modules/mount_ext2.c
> @@ -69,7 +69,7 @@ int mount_mount(const char *root, const
> if (!status)
> existed = 0;
>
> - if (is_mounted(_PATH_MOUNTED, fullpath)) {
> + if (is_mounted(path_mounted, fullpath)) {
> error(MODPREFIX
> "warning: %s is already mounted", fullpath);
> return 0;
> diff --git a/modules/mount_generic.c b/modules/mount_generic.c
> index b3179d6..0fe6a3d 100644
> --- a/modules/mount_generic.c
> +++ b/modules/mount_generic.c
> @@ -68,7 +68,7 @@ int mount_mount(const char *root, const
> if (!status)
> existed = 0;
>
> - if (is_mounted(_PATH_MOUNTED, fullpath)) {
> + if (is_mounted(path_mounted, fullpath)) {
> error(MODPREFIX "warning: %s is already mounted", fullpath);
> return 0;
> }
> diff --git a/modules/mount_nfs.c b/modules/mount_nfs.c
> index 3f9de50..c0546b9 100644
> --- a/modules/mount_nfs.c
> +++ b/modules/mount_nfs.c
> @@ -596,7 +596,7 @@ #endif
> if (!status)
> existed = 0;
>
> - if (is_mounted(_PATH_MOUNTED, fullpath)) {
> + if (is_mounted(path_mounted, fullpath)) {
> error(MODPREFIX
> "warning: %s is already mounted", fullpath);
> return 0;
>
_______________________________________________
autofs mailing list
[email protected]
http://linux.kernel.org/mailman/listinfo/autofs
