Use dev_t for devnm2devid and devid2devnm

Commit 4dd2df0966ec added a trip through makedev(), major(), and minor() for
device major and minor numbers. This would cause mdadm to fail in operating
on a device with a minor number bigger than (2^19)-1 due to it changing
from dev_t to a signed int and back.

Where this was found as a problem was when a array was created with a device
specified as a name like /dev/md/raidname and there were already 128 arrays
on the system. In this case, mdadm would chose 1048575 ((2^20)-1) for the
array and minor number. This would cause the major and minor number to become
negative when generated from devnm2devid() and passed to major() and minor()
in open_dev_excl(). open_dev_excl() would then call dev_open() which would
detect the negative minor number and call open() on the *char containing the
major:minor pair which isn't a valid file.

Signed-off-by: Mike Lovell <mlovell@bluehost.com>
Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/mdopen.c b/mdopen.c
index 28410f46..e71d7586 100644
--- a/mdopen.c
+++ b/mdopen.c
@@ -348,7 +348,7 @@ int create_mddev(char *dev, char *name, int autof, int trustworthy,
 		if (lstat(devname, &stb) == 0) {
 			/* Must be the correct device, else error */
 			if ((stb.st_mode&S_IFMT) != S_IFBLK ||
-			    stb.st_rdev != (dev_t)devnm2devid(devnm)) {
+			    stb.st_rdev != devnm2devid(devnm)) {
 				pr_err("%s exists but looks wrong, please fix\n",
 					devname);
 				return -1;
@@ -452,7 +452,7 @@ char *find_free_devnm(int use_partitions)
 		if (!use_udev()) {
 			/* make sure it is new to /dev too, at least as a
 			 * non-standard */
-			int devid = devnm2devid(devnm);
+			dev_t devid = devnm2devid(devnm);
 			if (devid) {
 				char *dn = map_dev(major(devid),
 						   minor(devid), 0);