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 <mwilck@xxxxxxxx>
---
libmultipath/wwids.c | 102 +++++++++++++++++++++++++++++++++++++++++++++++++++
libmultipath/wwids.h | 4 +-
2 files changed, 105 insertions(+), 1 deletion(-)
diff --git a/libmultipath/wwids.c b/libmultipath/wwids.c
index 5a2e86dcd7e2..e0fdcb34dbc6 100644
--- a/libmultipath/wwids.c
+++ b/libmultipath/wwids.c
@@ -5,6 +5,7 @@
#include <limits.h>
#include <stdio.h>
#include <sys/types.h>
+#include <sys/stat.h>
#include "checkers.h"
#include "vector.h"
@@ -331,3 +332,104 @@ remember_wwid(char *wwid)
condlog(4, "wwid %s already in wwids file", wwid);
return ret;
}
+
+static const char shm_dir[] = "/dev/shm/multipath/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 int multipath_shm_open(bool rw)
+{
+ int fd;
+ int can_write;
+
+ if (shm_lock_path[0] == '\0')
+ snprintf(_shm_lock_path, sizeof(_shm_lock_path),
+ "%s/%s", shm_dir, shm_lock);
+ 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;
+}
+
+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 == -1)
+ condlog(1, "%s: %s: %s", msg, wwid, strerror(errno));
+ else if (rw && r == 1) /* r == 0 means nothing changed */
+ condlog(3, "%s: %s", msg, wwid);
+ else if (!rw)
+ condlog(4, "%s: %s is %s", msg, wwid, r ? "failed" : "good");
+
+ return r;
+}
+
+static int _is_failed(const char *path)
+{
+ struct stat st;
+
+ if (lstat(path, &st) == 0)
+ return 1;
+ else if (errno == ENOENT)
+ return 0;
+ else
+ return -1;
+}
+
+static int _mark_failed(const char *path)
+{
+ /* Called from _failed_wwid_op: we know that shm_lock_path exists */
+ if (_is_failed(path) == 1)
+ return 0;
+ return (link(shm_lock_path, path) == 0 ? 1 : -1);
+}
+
+static int _unmark_failed(const char *path)
+{
+ if (_is_failed(path) == 0)
+ return 0;
+ return (unlink(path) == 0 ? 1 : -1);
+}
+
+#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 d9a78b38ccf8..d00e1f58137c 100644
--- a/libmultipath/wwids.h
+++ b/libmultipath/wwids.h
@@ -17,5 +17,7 @@ int remember_wwid(char *wwid);
int check_wwids_file(char *wwid, int write_wwid);
int remove_wwid(char *wwid);
int replace_wwids(vector mp);
-
+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
--
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