[dm-devel] [PATCH 1/2] libmultipath: check if user_friendly_name is in use
Benjamin Marzinski
bmarzins at redhat.com
Wed Mar 10 21:15:14 UTC 2021
If there are multipath devices that have user_friendly_names but do not
have their bindings in the bindings_file, get_user_friendly_alias() can
currently give out those names again. This can result in an incorrect
entry in the bindings file, and a device that gets created with a WWID
alias instead of a user_friendly_name. This situation can happen after
the pivot root, if a multipath device is created in the initramfs. If
this device doesn't have a binding in the regular filesystem
bindings_file and a new multipath device is created before it can add
its binding, the new device can steal that user_friendly_name during
multipathd's initial configure.
To solve this, get_user_friendly_alias() now calls lookup_binding() with
a new paramter, telling it to check if the id it found is already in use
by a diffent device. If so, lookup_binding() will continue to check open
ids, until it finds one that it not currently in use by a dm device.
Signed-off-by: Benjamin Marzinski <bmarzins at redhat.com>
---
libmultipath/alias.c | 48 +++++++++++++++++++++++++++++++++++++++++---
tests/alias.c | 22 ++++++++++----------
2 files changed, 56 insertions(+), 14 deletions(-)
diff --git a/libmultipath/alias.c b/libmultipath/alias.c
index a7ba485a..02bc9d65 100644
--- a/libmultipath/alias.c
+++ b/libmultipath/alias.c
@@ -21,6 +21,7 @@
#include "config.h"
#include "util.h"
#include "errno.h"
+#include "devmapper.h"
/*
@@ -119,6 +120,28 @@ scan_devname(const char *alias, const char *prefix)
return n;
}
+static int
+id_already_taken(int id, const char *prefix, const char *map_wwid)
+{
+ char alias[LINE_MAX];
+
+ if (format_devname(alias, id, LINE_MAX, prefix) < 0)
+ return 0;
+
+ if (dm_map_present(alias)) {
+ char wwid[WWID_SIZE];
+
+ /* If both the name and the wwid match, then it's fine.*/
+ if (dm_get_uuid(alias, wwid, sizeof(wwid)) == 0 &&
+ strncmp(map_wwid, wwid, sizeof(wwid)) == 0)
+ return 0;
+ condlog(3, "%s: alias '%s' already taken, but not in bindings file. reselecting alias", map_wwid, alias);
+ return 1;
+ }
+ return 0;
+}
+
+
/*
* Returns: 0 if matching entry in WWIDs file found
* -1 if an error occurs
@@ -128,7 +151,7 @@ scan_devname(const char *alias, const char *prefix)
*/
static int
lookup_binding(FILE *f, const char *map_wwid, char **map_alias,
- const char *prefix)
+ const char *prefix, int check_if_taken)
{
char buf[LINE_MAX];
unsigned int line_nr = 0;
@@ -183,12 +206,31 @@ lookup_binding(FILE *f, const char *map_wwid, char **map_alias,
return 0;
}
}
+ if (!prefix && check_if_taken)
+ id = -1;
if (id >= smallest_bigger_id) {
if (biggest_id < INT_MAX)
id = biggest_id + 1;
else
id = -1;
}
+ if (id > 0 && check_if_taken) {
+ while(id_already_taken(id, prefix, map_wwid)) {
+ if (id == INT_MAX) {
+ id = -1;
+ break;
+ }
+ id++;
+ if (id == smallest_bigger_id) {
+ if (biggest_id == INT_MAX) {
+ id = -1;
+ break;
+ }
+ if (biggest_id >= smallest_bigger_id)
+ id = biggest_id + 1;
+ }
+ }
+ }
if (id < 0) {
condlog(0, "no more available user_friendly_names");
return -1;
@@ -331,7 +373,7 @@ use_existing_alias (const char *wwid, const char *file, const char *alias_old,
goto out;
}
- id = lookup_binding(f, wwid, &alias, NULL);
+ id = lookup_binding(f, wwid, &alias, NULL, 0);
if (alias) {
condlog(3, "Use existing binding [%s] for WWID [%s]",
alias, wwid);
@@ -388,7 +430,7 @@ get_user_friendly_alias(const char *wwid, const char *file, const char *prefix,
return NULL;
}
- id = lookup_binding(f, wwid, &alias, prefix);
+ id = lookup_binding(f, wwid, &alias, prefix, 1);
if (id < 0) {
fclose(f);
return NULL;
diff --git a/tests/alias.c b/tests/alias.c
index 5e0bfea3..344aba73 100644
--- a/tests/alias.c
+++ b/tests/alias.c
@@ -357,7 +357,7 @@ static void lb_empty(void **state)
will_return(__wrap_fgets, NULL);
expect_condlog(3, "No matching wwid [WWID0] in bindings file.\n");
- rc = lookup_binding(NULL, "WWID0", &alias, NULL);
+ rc = lookup_binding(NULL, "WWID0", &alias, NULL, 0);
assert_int_equal(rc, 1);
assert_ptr_equal(alias, NULL);
}
@@ -370,7 +370,7 @@ static void lb_match_a(void **state)
will_return(__wrap_fgets, "MPATHa WWID0\n");
expect_condlog(3, "Found matching wwid [WWID0] in bindings file."
" Setting alias to MPATHa\n");
- rc = lookup_binding(NULL, "WWID0", &alias, "MPATH");
+ rc = lookup_binding(NULL, "WWID0", &alias, "MPATH", 0);
assert_int_equal(rc, 0);
assert_ptr_not_equal(alias, NULL);
assert_string_equal(alias, "MPATHa");
@@ -385,7 +385,7 @@ static void lb_nomatch_a(void **state)
will_return(__wrap_fgets, "MPATHa WWID0\n");
will_return(__wrap_fgets, NULL);
expect_condlog(3, "No matching wwid [WWID1] in bindings file.\n");
- rc = lookup_binding(NULL, "WWID1", &alias, "MPATH");
+ rc = lookup_binding(NULL, "WWID1", &alias, "MPATH", 0);
assert_int_equal(rc, 2);
assert_ptr_equal(alias, NULL);
}
@@ -399,7 +399,7 @@ static void lb_match_c(void **state)
will_return(__wrap_fgets, "MPATHc WWID1\n");
expect_condlog(3, "Found matching wwid [WWID1] in bindings file."
" Setting alias to MPATHc\n");
- rc = lookup_binding(NULL, "WWID1", &alias, "MPATH");
+ rc = lookup_binding(NULL, "WWID1", &alias, "MPATH", 0);
assert_int_equal(rc, 0);
assert_ptr_not_equal(alias, NULL);
assert_string_equal(alias, "MPATHc");
@@ -415,7 +415,7 @@ static void lb_nomatch_a_c(void **state)
will_return(__wrap_fgets, "MPATHc WWID1\n");
will_return(__wrap_fgets, NULL);
expect_condlog(3, "No matching wwid [WWID2] in bindings file.\n");
- rc = lookup_binding(NULL, "WWID2", &alias, "MPATH");
+ rc = lookup_binding(NULL, "WWID2", &alias, "MPATH", 0);
assert_int_equal(rc, 2);
assert_ptr_equal(alias, NULL);
}
@@ -429,7 +429,7 @@ static void lb_nomatch_c_a(void **state)
will_return(__wrap_fgets, "MPATHa WWID0\n");
will_return(__wrap_fgets, NULL);
expect_condlog(3, "No matching wwid [WWID2] in bindings file.\n");
- rc = lookup_binding(NULL, "WWID2", &alias, "MPATH");
+ rc = lookup_binding(NULL, "WWID2", &alias, "MPATH", 0);
assert_int_equal(rc, 2);
assert_ptr_equal(alias, NULL);
}
@@ -444,7 +444,7 @@ static void lb_nomatch_a_b(void **state)
will_return(__wrap_fgets, "MPATHb WWID1\n");
will_return(__wrap_fgets, NULL);
expect_condlog(3, "No matching wwid [WWID2] in bindings file.\n");
- rc = lookup_binding(NULL, "WWID2", &alias, "MPATH");
+ rc = lookup_binding(NULL, "WWID2", &alias, "MPATH", 0);
assert_int_equal(rc, 3);
assert_ptr_equal(alias, NULL);
}
@@ -460,7 +460,7 @@ static void lb_nomatch_a_b_bad(void **state)
will_return(__wrap_fgets, NULL);
expect_condlog(3, "Ignoring malformed line 3 in bindings file\n");
expect_condlog(3, "No matching wwid [WWID2] in bindings file.\n");
- rc = lookup_binding(NULL, "WWID2", &alias, "MPATH");
+ rc = lookup_binding(NULL, "WWID2", &alias, "MPATH", 0);
assert_int_equal(rc, 3);
assert_ptr_equal(alias, NULL);
}
@@ -475,7 +475,7 @@ static void lb_nomatch_b_a(void **state)
will_return(__wrap_fgets, "MPATHa WWID0\n");
will_return(__wrap_fgets, NULL);
expect_condlog(3, "No matching wwid [WWID2] in bindings file.\n");
- rc = lookup_binding(NULL, "WWID2", &alias, "MPATH");
+ rc = lookup_binding(NULL, "WWID2", &alias, "MPATH", 0);
assert_int_equal(rc, 27);
assert_ptr_equal(alias, NULL);
}
@@ -491,7 +491,7 @@ static void lb_nomatch_int_max(void **state)
will_return(__wrap_fgets, "MPATHa WWID0\n");
will_return(__wrap_fgets, NULL);
expect_condlog(0, "no more available user_friendly_names\n");
- rc = lookup_binding(NULL, "WWID2", &alias, "MPATH");
+ rc = lookup_binding(NULL, "WWID2", &alias, "MPATH", 0);
assert_int_equal(rc, -1);
assert_ptr_equal(alias, NULL);
}
@@ -506,7 +506,7 @@ static void lb_nomatch_int_max_m1(void **state)
will_return(__wrap_fgets, "MPATHa WWID0\n");
will_return(__wrap_fgets, NULL);
expect_condlog(3, "No matching wwid [WWID2] in bindings file.\n");
- rc = lookup_binding(NULL, "WWID2", &alias, "MPATH");
+ rc = lookup_binding(NULL, "WWID2", &alias, "MPATH", 0);
assert_int_equal(rc, INT_MAX);
assert_ptr_equal(alias, NULL);
}
--
2.17.2
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