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/*
* Copyright (C) 2011 Red Hat, Inc. All rights reserved.
*
* This file is part of LVM2.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU Lesser General Public License v.2.1.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "lib.h"
#include "filter.h"
#include "filter-mpath.h"
#include "activate.h"
#ifdef linux
#include <dirent.h>
#define MPATH_PREFIX "mpath-"
static const char *get_sysfs_name(struct device *dev)
{
const char *name;
if (!(name = strrchr(dev_name(dev), '/'))) {
log_error("Cannot find '/' in device name.");
return NULL;
}
name++;
if (!*name) {
log_error("Device name is not valid.");
return NULL;
}
return name;
}
static int get_sysfs_string(const char *path, char *buffer, int max_size)
{
FILE *fp;
int r = 0;
if (!(fp = fopen(path, "r"))) {
log_sys_error("fopen", path);
return 0;
}
if (!fgets(buffer, max_size, fp))
log_sys_error("fgets", path);
else
r = 1;
if (fclose(fp))
log_sys_error("fclose", path);
return r;
}
static int get_sysfs_get_major_minor(const char *sysfs_dir, const char *kname, int *major, int *minor)
{
char path[PATH_MAX], buffer[64];
if (dm_snprintf(path, sizeof(path), "%s/block/%s/dev", sysfs_dir, kname) < 0) {
log_error("Sysfs path string is too long.");
return 0;
}
if (!get_sysfs_string(path, buffer, sizeof(buffer)))
return_0;
if (sscanf(buffer, "%d:%d", major, minor) != 2) {
log_error("Failed to parse major minor from %s", buffer);
return 0;
}
return 1;
}
static int get_parent_mpath(const char *dir, char *name, int max_size)
{
struct dirent *d;
DIR *dr;
int r = 0;
if (!(dr = opendir(dir))) {
log_sys_error("opendir", dir);
return 0;
}
*name = '\0';
while ((d = readdir(dr))) {
if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
continue;
/* There should be only one holder if it is multipath */
if (*name) {
r = 0;
break;
}
strncpy(name, d->d_name, max_size);
r = 1;
}
if (closedir(dr))
log_sys_error("closedir", dir);
return r;
}
static int dev_is_mpath(struct dev_filter *f, struct device *dev)
{
const char *name;
char path[PATH_MAX+1];
char parent_name[PATH_MAX+1];
struct stat info;
const char *sysfs_dir = f->private;
int major, minor;
/* Limit this filter only to SCSI devices */
if (!major_is_scsi_device(MAJOR(dev->dev)))
return 0;
if (!(name = get_sysfs_name(dev)))
return_0;
if (dm_snprintf(path, PATH_MAX, "%s/block/%s/holders", sysfs_dir, name) < 0) {
log_error("Sysfs path to check mpath is too long.");
return 0;
}
/* also will filter out partitions */
if (stat(path, &info))
return 0;
if (!S_ISDIR(info.st_mode)) {
log_error("Path %s is not a directory.", path);
return 0;
}
if (!get_parent_mpath(path, parent_name, PATH_MAX))
return 0;
if (!get_sysfs_get_major_minor(sysfs_dir, parent_name, &major, &minor))
return_0;
if (major != dm_major()) {
log_error("mpath major %d is not dm major %d.", major, dm_major());
return 0;
}
return lvm_dm_prefix_check(major, minor, MPATH_PREFIX);
}
static int _ignore_mpath(struct dev_filter *f, struct device *dev)
{
if (dev_is_mpath(f, dev) == 1) {
log_debug("%s: Skipping mpath component device", dev_name(dev));
return 0;
}
return 1;
}
static void _destroy(struct dev_filter *f)
{
if (f->use_count)
log_error(INTERNAL_ERROR "Destroying mpath filter while in use %u times.", f->use_count);
dm_free(f->private);
dm_free(f);
}
struct dev_filter *mpath_filter_create(const char *sysfs_dir)
{
struct dev_filter *f;
if (!*sysfs_dir) {
log_verbose("No proc filesystem found: skipping multipath filter");
return NULL;
}
if (!(f = dm_malloc(sizeof(*f)))) {
log_error("mpath filter allocation failed");
return NULL;
}
f->passes_filter = _ignore_mpath;
f->destroy = _destroy;
f->use_count = 0;
if (!(f->private = dm_strdup(sysfs_dir))) {
log_error("Cannot duplicate sysfs dir.");
dm_free(f);
return NULL;
}
return f;
}
#else
struct dev_filter *mpath_filter_create(const char *sysfs_dir __attribute__((unused)))
{
return NULL;
}
#endif
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