block: do_mounts - accept root=<non-existant partition>
Some devices, like md, may create partitions only at first access,
so allow root= to be set to a valid non-existant partition of an
existing disk. This applies only to non-initramfs root mounting.
This fixes a regression from 2.6.24 which did allow this to happen and
broke some users machines :(
Acked-by: Neil Brown <neilb@suse.de>
Tested-by: Joao Luis Meloni Assirati <assirati@nonada.if.usp.br>
Cc: stable <stable@kernel.org>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 3885e70..660c1e5 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -76,6 +76,7 @@
char s[32];
char *p;
dev_t res = 0;
+ int part;
if (strncmp(name, "/dev/", 5) != 0) {
unsigned maj, min;
@@ -106,7 +107,31 @@
for (p = s; *p; p++)
if (*p == '/')
*p = '!';
- res = blk_lookup_devt(s);
+ res = blk_lookup_devt(s, 0);
+ if (res)
+ goto done;
+
+ /*
+ * try non-existant, but valid partition, which may only exist
+ * after revalidating the disk, like partitioned md devices
+ */
+ while (p > s && isdigit(p[-1]))
+ p--;
+ if (p == s || !*p || *p == '0')
+ goto fail;
+
+ /* try disk name without <part number> */
+ part = simple_strtoul(p, NULL, 10);
+ *p = '\0';
+ res = blk_lookup_devt(s, part);
+ if (res)
+ goto done;
+
+ /* try disk name without p<part number> */
+ if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
+ goto fail;
+ p[-1] = '\0';
+ res = blk_lookup_devt(s, part);
if (res)
goto done;
