From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Benjamin Marzinski Date: Tue, 19 May 2020 12:08:41 -0500 Subject: [PATCH] libmultipath: make sysfs_is_multipathed able to return wwid sysfs_is_multipathed reads the wwid of the dm device holding a path to check if its a multipath device. Add code to optinally set pp->wwid to that wwid. This will be used by a future patch. Reviewed-by: Martin Wilck Signed-off-by: Benjamin Marzinski --- libmultipath/sysfs.c | 24 +++++++++++++++++++----- libmultipath/sysfs.h | 2 +- multipath/main.c | 7 ++++--- 3 files changed, 24 insertions(+), 9 deletions(-) diff --git a/libmultipath/sysfs.c b/libmultipath/sysfs.c index 62ec2ed7..12a82d95 100644 --- a/libmultipath/sysfs.c +++ b/libmultipath/sysfs.c @@ -295,7 +295,7 @@ static int select_dm_devs(const struct dirent *di) return fnmatch("dm-*", di->d_name, FNM_FILE_NAME) == 0; } -bool sysfs_is_multipathed(const struct path *pp) +bool sysfs_is_multipathed(struct path *pp, bool set_wwid) { char pathbuf[PATH_MAX]; struct scandir_result sr; @@ -325,7 +325,7 @@ bool sysfs_is_multipathed(const struct path *pp) for (i = 0; i < r && !found; i++) { long fd; int nr; - char uuid[6]; + char uuid[WWID_SIZE + UUID_PREFIX_LEN]; if (safe_snprintf(pathbuf + n, sizeof(pathbuf) - n, "/%s/dm/uuid", di[i]->d_name)) @@ -339,12 +339,26 @@ bool sysfs_is_multipathed(const struct path *pp) pthread_cleanup_push(close_fd, (void *)fd); nr = read(fd, uuid, sizeof(uuid)); - if (nr == sizeof(uuid) && !memcmp(uuid, "mpath-", sizeof(uuid))) + if (nr > (int)UUID_PREFIX_LEN && + !memcmp(uuid, UUID_PREFIX, UUID_PREFIX_LEN)) found = true; else if (nr < 0) { - condlog(1, "%s: error reading from %s: %s", - __func__, pathbuf, strerror(errno)); + condlog(1, "%s: error reading from %s: %m", + __func__, pathbuf); } + if (found && set_wwid) { + nr -= UUID_PREFIX_LEN; + memcpy(pp->wwid, uuid + UUID_PREFIX_LEN, nr); + if (nr == WWID_SIZE) { + condlog(4, "%s: overflow while reading from %s", + __func__, pathbuf); + pp->wwid[0] = '\0'; + } else { + pp->wwid[nr] = '\0'; + strchop(pp->wwid); + } + } + pthread_cleanup_pop(1); } pthread_cleanup_pop(1); diff --git a/libmultipath/sysfs.h b/libmultipath/sysfs.h index 9ae30b39..72b39ab2 100644 --- a/libmultipath/sysfs.h +++ b/libmultipath/sysfs.h @@ -14,5 +14,5 @@ ssize_t sysfs_bin_attr_get_value(struct udev_device *dev, const char *attr_name, unsigned char * value, size_t value_len); int sysfs_get_size (struct path *pp, unsigned long long * size); int sysfs_check_holders(char * check_devt, char * new_devt); -bool sysfs_is_multipathed(const struct path *pp); +bool sysfs_is_multipathed(struct path *pp, bool set_wwid); #endif diff --git a/multipath/main.c b/multipath/main.c index cf9d2a28..545ead87 100644 --- a/multipath/main.c +++ b/multipath/main.c @@ -638,7 +638,8 @@ configure (struct config *conf, enum mpath_cmds cmd, * Shortcut for find_multipaths smart: * Quick check if path is already multipathed. */ - if (sysfs_is_multipathed(VECTOR_SLOT(pathvec, 0))) { + if (sysfs_is_multipathed(VECTOR_SLOT(pathvec, 0), + false)) { r = RTVL_YES; goto print_valid; } @@ -747,8 +748,8 @@ configure (struct config *conf, enum mpath_cmds cmd, /* * Check if we raced with multipathd */ - r = sysfs_is_multipathed(VECTOR_SLOT(pathvec, 0)) ? - RTVL_YES : RTVL_NO; + r = sysfs_is_multipathed(VECTOR_SLOT(pathvec, 0), + false) ? RTVL_YES : RTVL_NO; } goto print_valid; } -- 2.17.2