[Cluster-devel] [PATCH] libgfs2: Return more context from is_pathname_mounted and rename it

[Andrew Price <anprice@redhat.com>]

This one fell off my radar somehow. Reviews appreciated.

Andy

On 12/10/13 23:14, Andrew Price wrote:
> is_pathname_mounted is renamed lgfs2_find_mnt and now returns more
> context through the isdev and mnt parameters. It now only takes one path
> and returns whether it is the name of the device or the mount point
> using *isdev. It also sets *mnt to the struct mntent found by
> getmntent() so that the caller can check its contents itself.
>
> Callers have been updated and a bug where gfs2_grow wasn't working when
> the device name was provided by the user has been fixed.
>
> Signed-off-by: Andrew Price <anprice@redhat.com>
> ---
>   gfs2/fsck/initialize.c |  9 ++++-----
>   gfs2/libgfs2/libgfs2.h |  3 ++-
>   gfs2/libgfs2/misc.c    | 55 ++++++++++++++++++++++++++++++--------------------
>   gfs2/mkfs/main_grow.c  | 24 ++++++++++++++++------
>   gfs2/mkfs/main_jadd.c  | 23 ++++++++++++++++-----
>   5 files changed, 75 insertions(+), 39 deletions(-)
>
> diff --git a/gfs2/fsck/initialize.c b/gfs2/fsck/initialize.c
> index 6612fe7..1cc15ec 100644
> --- a/gfs2/fsck/initialize.c
> +++ b/gfs2/fsck/initialize.c
> @@ -1475,7 +1475,8 @@ int initialize(struct gfs2_sbd *sdp, int force_check, int preen,
>
>   	sdp->device_fd = open(opts.device, open_flag);
>   	if (sdp->device_fd < 0) {
> -		int is_mounted, ro;
> +		int isdev;
> +		struct mntent *mnt;
>
>   		if (open_flag == O_RDONLY || errno != EBUSY) {
>   			log_crit( _("Unable to open device: %s\n"),
> @@ -1490,18 +1491,16 @@ int initialize(struct gfs2_sbd *sdp, int force_check, int preen,
>   		   function checks for device as well. */
>   		strncpy(sdp->device_name, opts.device,
>   			sizeof(sdp->device_name));
> -		sdp->path_name = sdp->device_name; /* This gets overwritten */
> -		is_mounted = is_pathname_mounted(sdp->path_name, sdp->device_name, &ro);
>   		/* If the device is busy, but not because it's mounted, fail.
>   		   This protects against cases where the file system is LVM
>   		   and perhaps mounted on a different node. */
> -		if (!is_mounted)
> +		if (lgfs2_find_mnt(opts.device, &isdev, &mnt) || mnt == NULL)
>   			goto mount_fail;
>   		/* If the device is mounted, but not mounted RO, fail.  This
>   		   protects them against cases where the file system is
>   		   mounted RW, but still allows us to check our own root
>   		   file system. */
> -		if (!ro)
> +		if (!hasmntopt(mnt, MNTOPT_RO))
>   			goto mount_fail;
>   		/* The device is mounted RO, so it's likely our own root
>   		   file system.  We can only do so much to protect the users
> diff --git a/gfs2/libgfs2/libgfs2.h b/gfs2/libgfs2/libgfs2.h
> index f864a08..993f605 100644
> --- a/gfs2/libgfs2/libgfs2.h
> +++ b/gfs2/libgfs2/libgfs2.h
> @@ -12,6 +12,7 @@
>   #include <linux/limits.h>
>   #include <endian.h>
>   #include <byteswap.h>
> +#include <mntent.h>
>
>   #include <linux/gfs2_ondisk.h>
>   #include "osi_list.h"
> @@ -714,7 +715,7 @@ extern int metafs_interrupted;
>   extern int compute_heightsize(struct gfs2_sbd *sdp, uint64_t *heightsize,
>   		uint32_t *maxheight, uint32_t bsize1, int diptrs, int inptrs);
>   extern int compute_constants(struct gfs2_sbd *sdp);
> -extern int is_pathname_mounted(char *path_name, char *device_name, int *ro_mount);
> +extern int lgfs2_find_mnt(const char *path, int *isdev, struct mntent **mnt);
>   extern int find_gfs2_meta(struct gfs2_sbd *sdp);
>   extern int dir_exists(const char *dir);
>   extern int mount_gfs2_meta(struct gfs2_sbd *sdp);
> diff --git a/gfs2/libgfs2/misc.c b/gfs2/libgfs2/misc.c
> index 7f500e6..6bc95a9 100644
> --- a/gfs2/libgfs2/misc.c
> +++ b/gfs2/libgfs2/misc.c
> @@ -102,20 +102,27 @@ int compute_constants(struct gfs2_sbd *sdp)
>   	return 0;
>   }
>
> -int is_pathname_mounted(char *path_name, char *device_name, int *ro_mount)
> +/**
> + * lgfs2_find_mnt - Find a mounted file system relating to a path.
> + * path:  The path
> + * isdev: Will be non-zero if the path is the device or zero if the path is the mount directory
> + * mnt:   When the return value is 0, this will either be NULL for "not found" or
> + *        it will point to the found mount point.
> + * Returns 0 to indicate a successful scan of the mount points or non-zero on error with errno set.
> + *         On success, *mnt will be NULL or a valid pointer as noted above.
> + */
> +int lgfs2_find_mnt(const char *path, int *isdev, struct mntent **mnt)
>   {
>   	FILE *fp;
> -	struct mntent *mnt;
>   	dev_t file_dev=0, file_rdev=0;
>   	ino_t file_ino=0;
>   	struct stat st_buf;
>
> -	*ro_mount = 0;
>   	if ((fp = setmntent("/proc/mounts", "r")) == NULL) {
>   		perror("open: /proc/mounts");
> -		return 0;
> +		return 1;
>   	}
> -	if (stat(path_name, &st_buf) == 0) {
> +	if (stat(path, &st_buf) == 0) {
>   		if (S_ISBLK(st_buf.st_mode)) {
>   #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */
>   			file_rdev = st_buf.st_rdev;
> @@ -125,42 +132,46 @@ int is_pathname_mounted(char *path_name, char *device_name, int *ro_mount)
>   			file_ino = st_buf.st_ino;
>   		}
>   	}
> -	while ((mnt = getmntent (fp)) != NULL) {
> +	while ((*mnt = getmntent(fp)) != NULL) {
>   		/* Check if they specified the device instead of mnt point */
> -		if (strcmp(device_name, mnt->mnt_fsname) == 0) {
> -			strcpy(path_name, mnt->mnt_dir); /* fix it */
> +		if (strcmp(path, (*mnt)->mnt_fsname) == 0) {
> +			*isdev = 1;
>   			break;
>   		}
> -		if (strcmp(path_name, mnt->mnt_dir) == 0) {
> -			strcpy(device_name, mnt->mnt_fsname); /* fix it */
> +		if (strcmp(path, (*mnt)->mnt_dir) == 0) {
> +			*isdev = 0;
>   			break;
>   		}
> -		if (stat(mnt->mnt_fsname, &st_buf) == 0) {
> +		if (stat((*mnt)->mnt_fsname, &st_buf) == 0) {
>   			if (S_ISBLK(st_buf.st_mode)) {
>   #ifndef __GNU__
> -				if (file_rdev && (file_rdev == st_buf.st_rdev))
> +				if (file_rdev && (file_rdev == st_buf.st_rdev)) {
> +					*isdev = 1;
>   					break;
> +				}
>   #endif  /* __GNU__ */
>   			} else {
>   				if (file_dev && ((file_dev == st_buf.st_dev) &&
> -						 (file_ino == st_buf.st_ino)))
> +						 (file_ino == st_buf.st_ino))) {
> +					*isdev = 0;
>   					break;
> +				}
>   			}
>   		}
>   	}
>   	endmntent (fp);
> -	if (mnt == NULL)
> -		return 0;
> -	if (stat(mnt->mnt_dir, &st_buf) < 0) {
> +	if (*mnt == NULL)
> +		return 0; /* Success. Answer is no. */
> +	if (stat((*mnt)->mnt_dir, &st_buf) < 0) {
>   		if (errno == ENOENT)
> -			return 0;
> +			return 1;
>   	}
>   	/* Can't trust fstype because / has "rootfs". */
> -	if (file_rdev && (st_buf.st_dev != file_rdev))
> -		return 0;
> -	if (hasmntopt(mnt, MNTOPT_RO))
> -               *ro_mount = 1;
> -	return 1; /* mounted */
> +	if (file_rdev && (st_buf.st_dev != file_rdev)) {
> +		errno = EINVAL;
> +		return 1;
> +	}
> +	return 0; /* Success. Answer is yes. */
>   }
>
>   static int lock_for_admin(struct gfs2_sbd *sdp)
> diff --git a/gfs2/mkfs/main_grow.c b/gfs2/mkfs/main_grow.c
> index 5db91d9..4c8807e 100644
> --- a/gfs2/mkfs/main_grow.c
> +++ b/gfs2/mkfs/main_grow.c
> @@ -323,7 +323,6 @@ main_grow(int argc, char *argv[])
>   	int rgcount, rindex_fd;
>   	char rindex_name[PATH_MAX];
>   	int error = EXIT_SUCCESS;
> -	int ro_mnt = 0;
>
>   	memset(sdp, 0, sizeof(struct gfs2_sbd));
>   	sdp->bsize = GFS2_DEFAULT_BSIZE;
> @@ -335,16 +334,29 @@ main_grow(int argc, char *argv[])
>   	
>   	while ((argc - optind) > 0) {
>   		int sane;
> +		int isdev = 0;
> +		struct mntent *mnt;
>   		struct rgrp_tree *last_rgrp;
>
> -		strncpy(sdp->device_name, argv[optind], PATH_MAX - 1);
> -		sdp->path_name = argv[optind++];
> -
> -		if ((!is_pathname_mounted(sdp->path_name, sdp->device_name, &ro_mnt))) {
> -			perror(sdp->path_name);
> +		if (lgfs2_find_mnt(argv[optind], &isdev, &mnt)) {
> +			perror(argv[optind]);
>   			exit(EXIT_FAILURE);
>   		}
>
> +		if (mnt == NULL) {
> +			fprintf(stderr, "%s: not a mounted gfs2 file system\n", argv[optind++]);
> +			continue;
> +		}
> +
> +		if (isdev) {
> +			strncpy(sdp->device_name, argv[optind], PATH_MAX - 1);
> +			sdp->path_name = mnt->mnt_dir;
> +		} else {
> +			strncpy(sdp->device_name, mnt->mnt_fsname, PATH_MAX - 1);
> +			sdp->path_name = argv[optind];
> +		}
> +		optind++;
> +
>   		sdp->path_fd = open(sdp->path_name, O_RDONLY | O_CLOEXEC);
>   		if (sdp->path_fd < 0){
>   			perror(sdp->path_name);
> diff --git a/gfs2/mkfs/main_jadd.c b/gfs2/mkfs/main_jadd.c
> index b6cd8e4..9240838 100644
> --- a/gfs2/mkfs/main_jadd.c
> +++ b/gfs2/mkfs/main_jadd.c
> @@ -490,8 +490,9 @@ add_j(struct gfs2_sbd *sdp)
>   void main_jadd(int argc, char *argv[])
>   {
>   	struct gfs2_sbd sbd, *sdp = &sbd;
> +	struct mntent *mnt;
>   	unsigned int total;
> -	int ro_mnt = 0;
> +	int isdev;
>
>   	memset(sdp, 0, sizeof(struct gfs2_sbd));
>   	sdp->jsize = GFS2_DEFAULT_JSIZE;
> @@ -500,14 +501,26 @@ void main_jadd(int argc, char *argv[])
>
>   	decode_arguments(argc, argv, sdp);
>   	verify_arguments(sdp);
> -	
> -	sdp->path_fd = open(sdp->path_name, O_RDONLY | O_CLOEXEC);
> -	if (sdp->path_fd < 0){
> +
> +	if (lgfs2_find_mnt(sdp->path_name, &isdev, &mnt)) {
>   		perror(sdp->path_name);
>   		exit(EXIT_FAILURE);
>   	}
>
> -	if (!is_pathname_mounted(sdp->path_name, sdp->device_name, &ro_mnt)) {
> +	if (mnt == NULL) {
> +		fprintf(stderr, "%s: not a mounted gfs2 file system\n", sdp->path_name);
> +		exit(EXIT_FAILURE);
> +	}
> +
> +	if (isdev) {
> +		strncpy(sdp->device_name, sdp->path_name, PATH_MAX - 1);
> +		sdp->path_name = mnt->mnt_dir;
> +	} else {
> +		strncpy(sdp->device_name, mnt->mnt_fsname, PATH_MAX - 1);
> +	}
> +
> +	sdp->path_fd = open(sdp->path_name, O_RDONLY | O_CLOEXEC);
> +	if (sdp->path_fd < 0){
>   		perror(sdp->path_name);
>   		exit(EXIT_FAILURE);
>   	}
>