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f8b52f2763
sysfs-based multipath component detection quit if a device had multiple holders, and in this case would fail to detect a device was an mpath component.
484 lines
12 KiB
C
484 lines
12 KiB
C
/*
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* Copyright (C) 2011 Red Hat, Inc. All rights reserved.
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*
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* This file is part of LVM2.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU Lesser General Public License v.2.1.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "base/memory/zalloc.h"
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#include "lib/misc/lib.h"
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#include "lib/activate/activate.h"
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#include "lib/commands/toolcontext.h"
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#include "lib/device/device_id.h"
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#ifdef UDEV_SYNC_SUPPORT
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#include <libudev.h>
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#include "lib/device/dev-ext-udev-constants.h"
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#endif
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#include <dirent.h>
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#define MPATH_PREFIX "mpath-"
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/*
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* This hash table keeps track of whether a given dm device
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* is a mpath device or not.
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*
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* If dm-3 is an mpath device, then the constant "2" is stored in
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* the hash table with the key of the dm minor number ("3" for dm-3).
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* If dm-3 is not an mpath device, then the constant "1" is stored in
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* the hash table with the key of the dm minor number.
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*/
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static struct dm_pool *_hash_mem;
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static struct dm_hash_table *_minor_hash_tab;
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static struct dm_hash_table *_wwid_hash_tab;
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#define MAX_WWID_LINE 512
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/*
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* do we need to check the multipath.conf blacklist?
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*/
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static void _read_wwid_file(const char *config_wwids_file)
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{
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FILE *fp;
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char line[MAX_WWID_LINE];
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char *wwid, *p;
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int count = 0;
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if (config_wwids_file[0] != '/') {
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log_print("Ignoring unknown multipath_wwids_file.");
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return;
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}
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if (!(fp = fopen(config_wwids_file, "r"))) {
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log_debug("multipath wwids file not found");
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return;
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}
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while (fgets(line, sizeof(line), fp)) {
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if (line[0] == '#')
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continue;
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wwid = line;
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if (line[0] == '/')
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wwid++;
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/* skip the initial '3' */
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wwid++;
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if ((p = strchr(wwid, '/')))
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*p = '\0';
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(void) dm_hash_insert_binary(_wwid_hash_tab, wwid, strlen(wwid), (void*)1);
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count++;
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}
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if (fclose(fp))
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stack;
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log_debug("multipath wwids read %d from %s", count, config_wwids_file);
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}
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int dev_mpath_init(const char *config_wwids_file)
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{
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struct dm_pool *mem;
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struct dm_hash_table *minor_tab;
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struct dm_hash_table *wwid_tab;
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if (!(mem = dm_pool_create("mpath", 256))) {
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log_error("mpath pool creation failed.");
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return 0;
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}
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if (!(minor_tab = dm_hash_create(110))) {
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log_error("mpath hash table creation failed.");
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dm_pool_destroy(mem);
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return 0;
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}
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_hash_mem = mem;
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_minor_hash_tab = minor_tab;
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/* multipath_wwids_file="" disables the use of the file */
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if (config_wwids_file && !strlen(config_wwids_file)) {
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log_debug("multipath wwids file disabled.");
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return 1;
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}
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if (!(wwid_tab = dm_hash_create(110))) {
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log_error("mpath hash table creation failed.");
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dm_hash_destroy(_minor_hash_tab);
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dm_pool_destroy(_hash_mem);
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_minor_hash_tab = NULL;
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_hash_mem = NULL;
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return 0;
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}
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_wwid_hash_tab = wwid_tab;
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_read_wwid_file(config_wwids_file);
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return 1;
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}
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void dev_mpath_exit(void)
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{
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if (_minor_hash_tab)
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dm_hash_destroy(_minor_hash_tab);
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if (_wwid_hash_tab)
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dm_hash_destroy(_wwid_hash_tab);
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if (_hash_mem)
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dm_pool_destroy(_hash_mem);
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_minor_hash_tab = NULL;
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_wwid_hash_tab = NULL;
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_hash_mem = NULL;
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}
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/*
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* given "/dev/foo" return "foo"
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*/
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static const char *_get_sysfs_name(struct device *dev)
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{
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const char *name;
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if (!(name = strrchr(dev_name(dev), '/'))) {
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log_error("Cannot find '/' in device name.");
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return NULL;
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}
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name++;
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if (!*name) {
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log_error("Device name is not valid.");
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return NULL;
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}
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return name;
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}
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/*
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* given major:minor
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* readlink translates /sys/dev/block/major:minor to /sys/.../foo
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* from /sys/.../foo return "foo"
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*/
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static const char *_get_sysfs_name_by_devt(const char *sysfs_dir, dev_t devno,
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char *buf, size_t buf_size)
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{
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const char *name;
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char path[PATH_MAX];
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int size;
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if (dm_snprintf(path, sizeof(path), "%sdev/block/%d:%d", sysfs_dir,
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(int) MAJOR(devno), (int) MINOR(devno)) < 0) {
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log_error("Sysfs path string is too long.");
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return NULL;
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}
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if ((size = readlink(path, buf, buf_size - 1)) < 0) {
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log_sys_error("readlink", path);
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return NULL;
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}
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buf[size] = '\0';
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if (!(name = strrchr(buf, '/'))) {
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log_error("Cannot find device name in sysfs path.");
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return NULL;
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}
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name++;
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return name;
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}
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static int _get_sysfs_string(const char *path, char *buffer, int max_size)
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{
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FILE *fp;
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int r = 0;
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if (!(fp = fopen(path, "r"))) {
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log_sys_error("fopen", path);
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return 0;
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}
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if (!fgets(buffer, max_size, fp))
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log_sys_error("fgets", path);
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else
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r = 1;
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if (fclose(fp))
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log_sys_error("fclose", path);
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return r;
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}
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static int _get_sysfs_dm_mpath(struct dev_types *dt, const char *sysfs_dir, const char *holder_name)
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{
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char path[PATH_MAX];
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char buffer[128];
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if (dm_snprintf(path, sizeof(path), "%sblock/%s/dm/uuid", sysfs_dir, holder_name) < 0) {
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log_error("Sysfs path string is too long.");
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return 0;
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}
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buffer[0] = '\0';
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if (!_get_sysfs_string(path, buffer, sizeof(buffer)))
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return_0;
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if (!strncmp(buffer, MPATH_PREFIX, 6))
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return 1;
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return 0;
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}
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#ifdef UDEV_SYNC_SUPPORT
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static int _dev_is_mpath_component_udev(struct device *dev)
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{
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const char *value;
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struct dev_ext *ext;
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/*
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* external_device_info_source="udev" enables these udev checks.
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* external_device_info_source="none" disables them.
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*/
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if (!(ext = dev_ext_get(dev)))
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return_0;
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value = udev_device_get_property_value((struct udev_device *)ext->handle, DEV_EXT_UDEV_BLKID_TYPE);
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if (value && !strcmp(value, DEV_EXT_UDEV_BLKID_TYPE_MPATH))
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return 1;
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value = udev_device_get_property_value((struct udev_device *)ext->handle, DEV_EXT_UDEV_MPATH_DEVICE_PATH);
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if (value && !strcmp(value, "1"))
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return 1;
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return 0;
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}
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#else
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static int _dev_is_mpath_component_udev(struct device *dev)
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{
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return 0;
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}
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#endif
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static int _dev_is_mpath_component_sysfs(struct cmd_context *cmd, struct device *dev)
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{
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struct dev_types *dt = cmd->dev_types;
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const char *part_name;
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const char *name; /* e.g. "sda" for "/dev/sda" */
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char link_path[PATH_MAX]; /* some obscure, unpredictable sysfs path */
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char holders_path[PATH_MAX]; /* e.g. "/sys/block/sda/holders/" */
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char dm_dev_path[PATH_MAX]; /* e.g. "/dev/dm-1" */
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char *holder_name; /* e.g. "dm-1" */
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const char *sysfs_dir = dm_sysfs_dir();
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DIR *dr;
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struct dirent *de;
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int dev_major = MAJOR(dev->dev);
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int dev_minor = MINOR(dev->dev);
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int dm_dev_major;
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int dm_dev_minor;
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struct stat info;
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dev_t primary_dev;
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int is_mpath_component = 0;
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/* multipathing is only known to exist for SCSI or NVME devices */
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if (!major_is_scsi_device(dt, dev_major) && !dev_is_nvme(dt, dev))
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return 0;
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switch (dev_get_primary_dev(dt, dev, &primary_dev)) {
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case 2: /* The dev is partition. */
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part_name = dev_name(dev); /* name of original dev for log_debug msg */
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/* gets "foo" for "/dev/foo" where "/dev/foo" comes from major:minor */
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if (!(name = _get_sysfs_name_by_devt(sysfs_dir, primary_dev, link_path, sizeof(link_path))))
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return_0;
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log_debug_devs("%s: Device is a partition, using primary "
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"device %s for mpath component detection",
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part_name, name);
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break;
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case 1: /* The dev is already a primary dev. Just continue with the dev. */
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/* gets "foo" for "/dev/foo" */
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if (!(name = _get_sysfs_name(dev)))
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return_0;
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break;
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default: /* 0, error. */
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log_warn("Failed to get primary device for %d:%d.", dev_major, dev_minor);
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return 0;
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}
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if (dm_snprintf(holders_path, sizeof(holders_path), "%sblock/%s/holders", sysfs_dir, name) < 0) {
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log_warn("Sysfs path to check mpath is too long.");
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return 0;
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}
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/* also will filter out partitions */
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if (stat(holders_path, &info))
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return 0;
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if (!S_ISDIR(info.st_mode)) {
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log_warn("Path %s is not a directory.", holders_path);
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return 0;
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}
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/*
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* If any holder is a dm mpath device, then return 1;
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*/
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if (!(dr = opendir(holders_path))) {
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log_debug("Device %s has no holders dir", dev_name(dev));
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return 0;
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}
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while ((de = readdir(dr))) {
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if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, ".."))
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continue;
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/*
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* holder_name is e.g. "dm-1"
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* dm_dev_path is then e.g. "/dev/dm-1"
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*/
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holder_name = de->d_name;
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if (dm_snprintf(dm_dev_path, sizeof(dm_dev_path), "%s/%s", cmd->dev_dir, holder_name) < 0) {
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log_warn("dm device path to check mpath is too long.");
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continue;
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}
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/*
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* stat "/dev/dm-1" which is the holder of the dev we're checking
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* dm_dev_major:dm_dev_minor come from stat("/dev/dm-1")
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*/
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if (stat(dm_dev_path, &info)) {
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log_debug_devs("dev_is_mpath_component %s holder %s stat result %d",
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dev_name(dev), dm_dev_path, errno);
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continue;
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}
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dm_dev_major = (int)MAJOR(info.st_rdev);
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dm_dev_minor = (int)MINOR(info.st_rdev);
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if (dm_dev_major != dt->device_mapper_major) {
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log_debug_devs("dev_is_mpath_component %s holder %s %d:%d does not have dm major",
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dev_name(dev), dm_dev_path, dm_dev_major, dm_dev_minor);
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continue;
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}
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/*
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* A previous call may have checked if dm_dev_minor is mpath and saved
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* the result in the hash table. If there's a saved result just use that.
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*
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* The minor number of "/dev/dm-1" is added to the hash table with
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* const value 2 meaning that dm minor 1 (for /dev/dm-1) is a multipath dev
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* and const value 1 meaning that dm minor 1 is not a multipath dev.
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*/
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if (_minor_hash_tab) {
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long look = (long) dm_hash_lookup_binary(_minor_hash_tab, &dm_dev_minor, sizeof(dm_dev_minor));
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if (look > 0) {
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log_debug_devs("dev_is_mpath_component %s holder %s %u:%u already checked as %sbeing mpath.",
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dev_name(dev), holder_name, dm_dev_major, dm_dev_minor, (look > 1) ? "" : "not ");
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is_mpath_component = (look == 2);
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goto out;
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}
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/* no saved result for dm_dev_minor, so check the uuid for it */
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}
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/*
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* Returns 1 if /sys/block/<holder_name>/dm/uuid indicates that
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* <holder_name> is a dm device with dm uuid prefix mpath-.
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* When true, <holder_name> will be something like "dm-1".
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*/
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if (_get_sysfs_dm_mpath(dt, sysfs_dir, holder_name)) {
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log_debug_devs("dev_is_mpath_component %s holder %s %u:%u ignore mpath component",
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dev_name(dev), holder_name, dm_dev_major, dm_dev_minor);
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/* For future checks, save that the dm minor refers to mpath ("2" == is mpath) */
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if (_minor_hash_tab)
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(void) dm_hash_insert_binary(_minor_hash_tab, &dm_dev_minor, sizeof(dm_dev_minor), (void*)2);
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is_mpath_component = 1;
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goto out;
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}
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/* For future checks, save that the dm minor does not refer to mpath ("1" == is not mpath) */
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if (_minor_hash_tab)
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(void) dm_hash_insert_binary(_minor_hash_tab, &dm_dev_minor, sizeof(dm_dev_minor), (void*)1);
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}
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out:
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if (closedir(dr))
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stack;
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return is_mpath_component;
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}
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static int _dev_in_wwid_file(struct cmd_context *cmd, struct device *dev)
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{
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char sysbuf[PATH_MAX] = { 0 };
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char *wwid;
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long look;
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if (!_wwid_hash_tab)
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return 0;
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if (!read_sys_block(cmd, dev, "device/wwid", sysbuf, sizeof(sysbuf)))
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return 0;
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if (!sysbuf[0])
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return 0;
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/*
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* sysfs prints wwid as <typestr>.<value>
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* multipath wwid uses '3'<value>
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* does "<typestr>." always correspond to "3"?
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*/
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if (!(wwid = strchr(sysbuf, '.')))
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return 0;
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/* skip the type and dot, just as '3' was skipped from wwids entry */
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wwid++;
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look = (long) dm_hash_lookup_binary(_wwid_hash_tab, wwid, strlen(wwid));
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if (look) {
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log_debug_devs("dev_is_mpath_component %s multipath wwid %s", dev_name(dev), wwid);
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return 1;
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}
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return 0;
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}
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int dev_is_mpath_component(struct cmd_context *cmd, struct device *dev)
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{
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if (_dev_is_mpath_component_sysfs(cmd, dev) == 1)
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goto found;
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if (_dev_in_wwid_file(cmd, dev))
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goto found;
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if (external_device_info_source() == DEV_EXT_UDEV) {
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if (_dev_is_mpath_component_udev(dev) == 1)
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goto found;
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}
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return 0;
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found:
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return 1;
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}
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