partition_delimiter is UNSET by default, falling back to the kernel
default behavior to use "p" for devices ending in a digit, and ""
for others. However, the udev rules for kpartx have always used the
delimiter "-part". If a map name is changed (e.g. if an alias is
reconfigured), multipathd first sets partition names e.g. to name "mpatha1",
which is later changed to "mpatha-part1" by kpartx during udev rule
processing. That's inefficient and superfluous. However, if a distribution
simply changed DEFAULT_PARTITION_DELIM to "-part", users wouldn't be able
to restore the default behavior any more.
This patch allows to set 'partition_delimiter "/UNSET/"' in multipath.conf
to force the previous default behavior, even if the distribution default is
something other than UNSET. The string "/UNSET/" is not a valid partition
delimiter because filenames can't contain slashes, thus user freedom isn't
constrained by this patch.
Signed-off-by: Martin Wilck <mwilck@xxxxxxxx>
---
libmultipath/config.c | 3 ++-
libmultipath/defaults.c | 2 ++
libmultipath/defaults.h | 2 ++
libmultipath/dict.c | 24 ++++++++++++++++++++++--
multipath/multipath.conf.5 | 16 ++++++++++++----
5 files changed, 40 insertions(+), 7 deletions(-)
diff --git a/libmultipath/config.c b/libmultipath/config.c
index fc0ec8d3..afa309da 100644
--- a/libmultipath/config.c
+++ b/libmultipath/config.c
@@ -704,7 +704,8 @@ load_config (char * file)
conf->checkint = DEFAULT_CHECKINT;
conf->max_checkint = 0;
conf->force_sync = DEFAULT_FORCE_SYNC;
- conf->partition_delim = DEFAULT_PARTITION_DELIM;
+ conf->partition_delim = (default_partition_delim != NULL ?
+ strdup(default_partition_delim) : NULL);
conf->processed_main_config = 0;
conf->find_multipaths = DEFAULT_FIND_MULTIPATHS;
conf->uxsock_timeout = DEFAULT_REPLY_TIMEOUT;
diff --git a/libmultipath/defaults.c b/libmultipath/defaults.c
index 7130e56f..c20bb0d2 100644
--- a/libmultipath/defaults.c
+++ b/libmultipath/defaults.c
@@ -6,6 +6,8 @@
#include "defaults.h"
#include "memory.h"
+const char * const default_partition_delim = DEFAULT_PARTITION_DELIM;
+
char *
set_default (char * str)
{
diff --git a/libmultipath/defaults.h b/libmultipath/defaults.h
index f076b4b0..7f3839fc 100644
--- a/libmultipath/defaults.h
+++ b/libmultipath/defaults.h
@@ -36,6 +36,7 @@
#define DEFAULT_FLUSH FLUSH_DISABLED
#define DEFAULT_USER_FRIENDLY_NAMES USER_FRIENDLY_NAMES_OFF
#define DEFAULT_FORCE_SYNC 0
+#define UNSET_PARTITION_DELIM "/UNSET/"
#define DEFAULT_PARTITION_DELIM NULL
#define DEFAULT_SKIP_KPARTX SKIP_KPARTX_OFF
#define DEFAULT_DISABLE_CHANGED_WWIDS 1
@@ -59,3 +60,4 @@
#define MULTIPATH_SHM_BASE "/dev/shm/multipath/"
char * set_default (char * str);
+extern const char *const default_partition_delim;
diff --git a/libmultipath/dict.c b/libmultipath/dict.c
index fc107e9b..d0188806 100644
--- a/libmultipath/dict.c
+++ b/libmultipath/dict.c
@@ -275,8 +275,28 @@ declare_def_snprint(reassign_maps, print_yes_no)
declare_def_handler(multipath_dir, set_str)
declare_def_snprint(multipath_dir, print_str)
-declare_def_handler(partition_delim, set_str)
-declare_def_snprint(partition_delim, print_str)
+static int def_partition_delim_handler(struct config *conf, vector strvec)
+{
+ int rc = set_str(strvec, &conf->partition_delim);
+
+ if (rc != 0)
+ return rc;
+
+ if (!strcmp(conf->partition_delim, UNSET_PARTITION_DELIM)) {
+ FREE(conf->partition_delim);
+ conf->partition_delim = NULL;
+ }
+ return 0;
+}
+
+static int snprint_def_partition_delim(struct config *conf, char *buff,
+ int len, const void *data)
+{
+ if (default_partition_delim == NULL || conf->partition_delim != NULL)
+ return print_str(buff, len, conf->partition_delim);
+ else
+ return print_str(buff, len, UNSET_PARTITION_DELIM);
+}
static const char * const find_multipaths_optvals[] = {
[FIND_MULTIPATHS_OFF] = "off",
diff --git a/multipath/multipath.conf.5 b/multipath/multipath.conf.5
index 109c3dc0..e4b25a05 100644
--- a/multipath/multipath.conf.5
+++ b/multipath/multipath.conf.5
@@ -858,10 +858,18 @@ The default is: \fBno\fR
.
.TP
.B partition_delimiter
-If this value is not set, when multipath renames a device, it will act just
-like the kpartx default does, only adding a \fI"p"\fR to names ending in a
-number. If this parameter is set, multipath will act like kpartx does with
-the \fI-p\fR option is used, and always add delimiter.
+This parameter controls how multipath chooses the names of partition devices
+of multipath maps if a multipath map is renamed (e.g. if a map alias is added
+or changed). If this parameter is set to a string other than "/UNSET/" (even
+the empty string), multipath inserts that string between device name and
+partition number to construct the partition device name.
+Otherwise (i.e. if this parameter is unset or has the value "/UNSET/"),
+the behavior depends on the map name: if it ends in a digit, a \fI"p"\fR is
+inserted between name and partition number; otherwise, the partition number is
+simply appended.
+Distributions may use a non-null default value for this option; in this case,
+the user must set it to "/UNSET/" to obtain the original \fB<unset>\fR
+behavior. Use \fImultipath -T\fR to check the current settings.
.RS
.TP
The default is: \fB<unset>\fR
--
2.17.1
--
dm-devel mailing list
dm-devel@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/dm-devel
