From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin Wilck Subject: [PATCH v3 09/20] libmultipath: functions to indicate mapping failure in /dev/shm Date: Mon, 2 Apr 2018 21:50:40 +0200 Message-ID: <20180402195051.26854-10-mwilck@suse.com> References: <20180402195051.26854-1-mwilck@suse.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180402195051.26854-1-mwilck@suse.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Christophe Varoqui , Benjamin Marzinski Cc: Julian Andres Klode , dm-devel@redhat.com, Martin Wilck List-Id: dm-devel.ids Create a simple API that indicates failure to create a map for a certain WWID. This will allow multipathd to indicate to other tools (in particular, "multipath -u" during udev processing) that an attempt to create a map for a certain wwid failed. The indicator is simply the existence of a file under /dev/shm/multipath/failed_wwids. Signed-off-by: Martin Wilck --- libmultipath/defaults.h | 1 + libmultipath/wwids.c | 110 ++++++++++++++++++++++++++++++++++++++++++++++++ libmultipath/wwids.h | 11 +++++ 3 files changed, 122 insertions(+) diff --git a/libmultipath/defaults.h b/libmultipath/defaults.h index 690182c..19ad2bf 100644 --- a/libmultipath/defaults.h +++ b/libmultipath/defaults.h @@ -53,5 +53,6 @@ #define DEFAULT_WWIDS_FILE "/etc/multipath/wwids" #define DEFAULT_PRKEYS_FILE "/etc/multipath/prkeys" #define DEFAULT_CONFIG_DIR "/etc/multipath/conf.d" +#define MULTIPATH_SHM_BASE "/dev/shm/multipath/" char * set_default (char * str); diff --git a/libmultipath/wwids.c b/libmultipath/wwids.c index 5a2e86d..5351e3c 100644 --- a/libmultipath/wwids.c +++ b/libmultipath/wwids.c @@ -5,6 +5,7 @@ #include #include #include +#include #include "checkers.h" #include "vector.h" @@ -331,3 +332,112 @@ remember_wwid(char *wwid) condlog(4, "wwid %s already in wwids file", wwid); return ret; } + +static const char shm_dir[] = MULTIPATH_SHM_BASE "failed_wwids"; +static const char shm_lock[] = ".lock"; +static const char shm_header[] = "multipath shm lock file, don't edit"; +static char _shm_lock_path[sizeof(shm_dir)+sizeof(shm_lock)]; +static const char *shm_lock_path = &_shm_lock_path[0]; + +static void init_shm_paths(void) +{ + snprintf(_shm_lock_path, sizeof(_shm_lock_path), + "%s/%s", shm_dir, shm_lock); +} + +static pthread_once_t shm_path_once = PTHREAD_ONCE_INIT; + +static int multipath_shm_open(bool rw) +{ + int fd; + int can_write; + + pthread_once(&shm_path_once, init_shm_paths); + fd = open_file(shm_lock_path, &can_write, shm_header); + + if (fd >= 0 && rw && !can_write) { + close(fd); + condlog(1, "failed to open %s for writing", shm_dir); + return -1; + } + + return fd; +} + +static void multipath_shm_close(void *arg) +{ + long fd = (long)arg; + + close(fd); + unlink(shm_lock_path); +} + +static int _failed_wwid_op(const char *wwid, bool rw, + int(*func)(const char*), const char *msg) +{ + char path[PATH_MAX]; + long lockfd; + int r = -1; + + if (snprintf(path, sizeof(path), "%s/%s", shm_dir, wwid) + >= sizeof(path)) { + condlog(1, "%s: path name overflow", __func__); + return -1; + } + + lockfd = multipath_shm_open(rw); + if (lockfd == -1) + return -1; + + pthread_cleanup_push(multipath_shm_close, (void*)lockfd); + r = func(path); + pthread_cleanup_pop(1); + + if (r == WWID_FAILED_ERROR) + condlog(1, "%s: %s: %s", msg, wwid, strerror(errno)); + else if (r == WWID_FAILED_CHANGED) + condlog(3, "%s: %s", msg, wwid); + else if (!rw) + condlog(4, "%s: %s is %s", msg, wwid, + r == WWID_IS_FAILED ? "failed" : "good"); + + return r; +} + +static int _is_failed(const char *path) +{ + struct stat st; + + if (lstat(path, &st) == 0) + return WWID_IS_FAILED; + else if (errno == ENOENT) + return WWID_IS_NOT_FAILED; + else + return WWID_FAILED_ERROR; +} + +static int _mark_failed(const char *path) +{ + /* Called from _failed_wwid_op: we know that shm_lock_path exists */ + if (_is_failed(path) == WWID_IS_FAILED) + return WWID_FAILED_UNCHANGED; + return (link(shm_lock_path, path) == 0 ? WWID_FAILED_CHANGED : + WWID_FAILED_ERROR); +} + +static int _unmark_failed(const char *path) +{ + if (_is_failed(path) == WWID_IS_NOT_FAILED) + return WWID_FAILED_UNCHANGED; + return (unlink(path) == 0 ? WWID_FAILED_CHANGED : WWID_FAILED_ERROR); +} + +#define declare_failed_wwid_op(op, rw) \ +int op ## _wwid(const char *wwid) \ +{ \ + return _failed_wwid_op(wwid, (rw), _ ## op, #op); \ +} + +declare_failed_wwid_op(is_failed, false) +declare_failed_wwid_op(mark_failed, true) +declare_failed_wwid_op(unmark_failed, true) diff --git a/libmultipath/wwids.h b/libmultipath/wwids.h index d9a78b3..0c6ee54 100644 --- a/libmultipath/wwids.h +++ b/libmultipath/wwids.h @@ -18,4 +18,15 @@ int check_wwids_file(char *wwid, int write_wwid); int remove_wwid(char *wwid); int replace_wwids(vector mp); +enum { + WWID_IS_NOT_FAILED = 0, + WWID_IS_FAILED, + WWID_FAILED_UNCHANGED, + WWID_FAILED_CHANGED, + WWID_FAILED_ERROR = -1, +}; + +int is_failed_wwid(const char *wwid); +int mark_failed_wwid(const char *wwid); +int unmark_failed_wwid(const char *wwid); #endif /* _WWIDS_H */ -- 2.16.1