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>
This commit is contained in:
Kay Sievers
2008-05-06 22:31:33 +02:00
committed by Greg Kroah-Hartman
parent 9604006d28
commit 30f2f0eb4b
3 changed files with 34 additions and 6 deletions

View File

@@ -76,6 +76,7 @@ dev_t name_to_dev_t(char *name)
char s[32];
char *p;
dev_t res = 0;
int part;
if (strncmp(name, "/dev/", 5) != 0) {
unsigned maj, min;
@@ -106,7 +107,31 @@ dev_t name_to_dev_t(char *name)
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;