/* * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "base/memory/zalloc.h" #include "lib/misc/lib.h" #include "lib/filters/filter.h" #include "lib/activate/activate.h" #include "lib/commands/toolcontext.h" #ifdef UDEV_SYNC_SUPPORT #include #include "lib/device/dev-ext-udev-constants.h" #endif #ifdef __linux__ #include #define MPATH_PREFIX "mpath-" struct mpath_priv { struct dm_pool *mem; struct dev_filter f; struct dev_types *dt; struct dm_hash_table *hash; }; /* * given "/dev/foo" return "foo" */ 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; } /* * given major:minor * readlink translates /sys/dev/block/major:minor to /sys/.../foo * from /sys/.../foo return "foo" */ static const char *_get_sysfs_name_by_devt(const char *sysfs_dir, dev_t devno, char *buf, size_t buf_size) { const char *name; char path[PATH_MAX]; int size; if (dm_snprintf(path, sizeof(path), "%sdev/block/%d:%d", sysfs_dir, (int) MAJOR(devno), (int) MINOR(devno)) < 0) { log_error("Sysfs path string is too long."); return NULL; } if ((size = readlink(path, buf, buf_size - 1)) < 0) { log_sys_error("readlink", path); return NULL; } buf[size] = '\0'; if (!(name = strrchr(buf, '/'))) { log_error("Cannot find device name in sysfs path."); return NULL; } name++; 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_dm_mpath(struct dev_types *dt, const char *sysfs_dir, const char *holder_name) { char path[PATH_MAX]; char buffer[128]; if (dm_snprintf(path, sizeof(path), "%sblock/%s/dm/uuid", sysfs_dir, holder_name) < 0) { log_error("Sysfs path string is too long."); return 0; } buffer[0] = '\0'; if (!_get_sysfs_string(path, buffer, sizeof(buffer))) return_0; if (!strncmp(buffer, MPATH_PREFIX, 6)) return 1; return 0; } static int _get_holder_name(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; } #ifdef UDEV_SYNC_SUPPORT static int _udev_dev_is_mpath_component(struct device *dev) { const char *value; struct dev_ext *ext; if (!(ext = dev_ext_get(dev))) return_0; value = udev_device_get_property_value((struct udev_device *)ext->handle, DEV_EXT_UDEV_BLKID_TYPE); if (value && !strcmp(value, DEV_EXT_UDEV_BLKID_TYPE_MPATH)) return 1; value = udev_device_get_property_value((struct udev_device *)ext->handle, DEV_EXT_UDEV_MPATH_DEVICE_PATH); if (value && !strcmp(value, "1")) return 1; return 0; } #else static int _udev_dev_is_mpath_component(struct device *dev) { return 0; } #endif static int _native_dev_is_mpath_component(struct cmd_context *cmd, struct dev_filter *f, struct device *dev) { struct mpath_priv *mp = (struct mpath_priv *) f->private; struct dev_types *dt = mp->dt; const char *part_name; const char *name; /* e.g. "sda" for "/dev/sda" */ char link_path[PATH_MAX]; /* some obscure, unpredictable sysfs path */ char holders_path[PATH_MAX]; /* e.g. "/sys/block/sda/holders/" */ char dm_dev_path[PATH_MAX]; /* e.g. "/dev/dm-1" */ char holder_name[128] = { 0 }; /* e.g. "dm-1" */ const char *sysfs_dir = dm_sysfs_dir(); int dev_major = MAJOR(dev->dev); int dev_minor = MINOR(dev->dev); int dm_dev_major; int dm_dev_minor; struct stat info; dev_t primary_dev; long look; /* Limit this filter to SCSI or NVME devices */ if (!major_is_scsi_device(dt, dev_major) && !dev_is_nvme(dt, dev)) return 0; switch (dev_get_primary_dev(dt, dev, &primary_dev)) { case 2: /* The dev is partition. */ part_name = dev_name(dev); /* name of original dev for log_debug msg */ /* gets "foo" for "/dev/foo" where "/dev/foo" comes from major:minor */ if (!(name = _get_sysfs_name_by_devt(sysfs_dir, primary_dev, link_path, sizeof(link_path)))) return_0; log_debug_devs("%s: Device is a partition, using primary " "device %s for mpath component detection", part_name, name); break; case 1: /* The dev is already a primary dev. Just continue with the dev. */ /* gets "foo" for "/dev/foo" */ if (!(name = _get_sysfs_name(dev))) return_0; break; default: /* 0, error. */ log_warn("Failed to get primary device for %d:%d.", dev_major, dev_minor); return 0; } if (dm_snprintf(holders_path, sizeof(holders_path), "%sblock/%s/holders", sysfs_dir, name) < 0) { log_warn("Sysfs path to check mpath is too long."); return 0; } /* also will filter out partitions */ if (stat(holders_path, &info)) return 0; if (!S_ISDIR(info.st_mode)) { log_warn("Path %s is not a directory.", holders_path); return 0; } /* * If holders dir contains an entry such as "dm-1", then this sets * holder_name to "dm-1". * * If holders dir is empty, return 0 (this is generally where * devs that are not mpath components return.) */ if (!_get_holder_name(holders_path, holder_name, sizeof(holder_name))) return 0; if (dm_snprintf(dm_dev_path, sizeof(dm_dev_path), "%s/%s", cmd->dev_dir, holder_name) < 0) { log_warn("dm device path to check mpath is too long."); return 0; } /* * stat "/dev/dm-1" which is the holder of the dev we're checking * dm_dev_major:dm_dev_minor come from stat("/dev/dm-1") */ if (stat(dm_dev_path, &info)) { log_debug("filter-mpath %s holder %s stat result %d", dev_name(dev), dm_dev_path, errno); return 0; } dm_dev_major = (int)MAJOR(info.st_rdev); dm_dev_minor = (int)MINOR(info.st_rdev); if (dm_dev_major != dt->device_mapper_major) { log_debug_devs("filter-mpath %s holder %s %d:%d does not have dm major", dev_name(dev), dm_dev_path, dm_dev_major, dm_dev_minor); return 0; } /* * Save the result of checking that "/dev/dm-1" is an mpath device * to avoid repeating it for each path component. * The minor number of "/dev/dm-1" is added to the hash table with * const value 2 meaning that dm minor 1 (for /dev/dm-1) is a multipath dev * and const value 1 meaning that dm minor 1 is not a multipath dev. */ look = (long) dm_hash_lookup_binary(mp->hash, &dm_dev_minor, sizeof(dm_dev_minor)); if (look > 0) { log_debug_devs("filter-mpath %s holder %s %u:%u already checked as %sbeing mpath.", dev_name(dev), holder_name, dm_dev_major, dm_dev_minor, (look > 1) ? "" : "not "); return (look > 1) ? 1 : 0; } /* * Returns 1 if /sys/block//dm/uuid indicates that * is a dm device with dm uuid prefix mpath-. * When true, will be something like "dm-1". * * (Is a hash table worth it to avoid reading one sysfs file?) */ if (_get_sysfs_dm_mpath(dt, sysfs_dir, holder_name)) { log_debug_devs("filter-mpath %s holder %s %u:%u ignore mpath component", dev_name(dev), holder_name, dm_dev_major, dm_dev_minor); (void) dm_hash_insert_binary(mp->hash, &dm_dev_minor, sizeof(dm_dev_minor), (void*)2); return 1; } (void) dm_hash_insert_binary(mp->hash, &dm_dev_minor, sizeof(dm_dev_minor), (void*)1); return 0; } static int _dev_is_mpath_component(struct cmd_context *cmd, struct dev_filter *f, struct device *dev) { if (dev->ext.src == DEV_EXT_NONE) return _native_dev_is_mpath_component(cmd, f, dev); if (dev->ext.src == DEV_EXT_UDEV) return _udev_dev_is_mpath_component(dev); log_error(INTERNAL_ERROR "Missing hook for mpath recognition " "using external device info source %s", dev_ext_name(dev)); return 0; } #define MSG_SKIPPING "%s: Skipping mpath component device" static int _ignore_mpath_component(struct cmd_context *cmd, struct dev_filter *f, struct device *dev, const char *use_filter_name) { dev->filtered_flags &= ~DEV_FILTERED_MPATH_COMPONENT; if (_dev_is_mpath_component(cmd, f, dev) == 1) { if (dev->ext.src == DEV_EXT_NONE) log_debug_devs(MSG_SKIPPING, dev_name(dev)); else log_debug_devs(MSG_SKIPPING " [%s:%p]", dev_name(dev), dev_ext_name(dev), dev->ext.handle); dev->filtered_flags |= DEV_FILTERED_MPATH_COMPONENT; return 0; } return 1; } static void _destroy(struct dev_filter *f) { struct mpath_priv *mp = (struct mpath_priv*) f->private; if (f->use_count) log_error(INTERNAL_ERROR "Destroying mpath filter while in use %u times.", f->use_count); dm_hash_destroy(mp->hash); dm_pool_destroy(mp->mem); } struct dev_filter *mpath_filter_create(struct dev_types *dt) { const char *sysfs_dir = dm_sysfs_dir(); struct mpath_priv *mp; struct dm_pool *mem; struct dm_hash_table *hash; if (!*sysfs_dir) { log_verbose("No proc filesystem found: skipping multipath filter"); return NULL; } if (!(hash = dm_hash_create(110))) { log_error("mpath hash table creation failed."); return NULL; } if (!(mem = dm_pool_create("mpath", 256))) { log_error("mpath pool creation failed."); dm_hash_destroy(hash); return NULL; } if (!(mp = dm_pool_zalloc(mem, sizeof(*mp)))) { log_error("mpath filter allocation failed."); goto bad; } mp->f.passes_filter = _ignore_mpath_component; mp->f.destroy = _destroy; mp->f.use_count = 0; mp->f.private = mp; mp->f.name = "mpath"; mp->dt = dt; mp->mem = mem; mp->hash = hash; log_debug_devs("mpath filter initialised."); return &mp->f; bad: dm_pool_destroy(mem); dm_hash_destroy(hash); return NULL; } #else struct dev_filter *mpath_filter_create(struct dev_types *dt) { return NULL; } #endif