Commit 30f2f0eb authored by Kay Sievers's avatar Kay Sievers Committed by Greg Kroah-Hartman
Browse files

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: default avatarNeil Brown <neilb@suse.de>
Tested-by: default avatarJoao Luis Meloni Assirati <assirati@nonada.if.usp.br>
Cc: stable <stable@kernel.org>
Signed-off-by: default avatarKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 9604006d

block/genhd.c

+6 −3
Original line number Diff line number Diff line
@@ -653,7 +653,7 @@ void genhd_media_change_notify(struct gendisk *disk) 
EXPORT_SYMBOL_GPL(genhd_media_change_notify);

#endif  /*  0  */



dev_t blk_lookup_devt(const char *name)

dev_t blk_lookup_devt(const char *name, int part)

{

	struct device *dev;

	dev_t devt = MKDEV(0, 0);
@@ -661,7 +661,11 @@ dev_t blk_lookup_devt(const char *name) 
	mutex_lock(&block_class_lock);

	list_for_each_entry(dev, &block_class.devices, node) {

		if (strcmp(dev->bus_id, name) == 0) {

			devt = dev->devt;

			struct gendisk *disk = dev_to_disk(dev);



			if (part < disk->minors)

				devt = MKDEV(MAJOR(dev->devt),

					     MINOR(dev->devt) + part);

			break;

		}

	}
@@ -669,7 +673,6 @@ dev_t blk_lookup_devt(const char *name) 


	return devt;

}



EXPORT_SYMBOL(blk_lookup_devt);



struct gendisk *alloc_disk(int minors)

include/linux/genhd.h

+2 −2
Original line number Diff line number Diff line
@@ -525,7 +525,7 @@ struct unixware_disklabel { 
#define ADDPART_FLAG_RAID	1

#define ADDPART_FLAG_WHOLEDISK	2



extern dev_t blk_lookup_devt(const char *name);

extern dev_t blk_lookup_devt(const char *name, int part);

extern char *disk_name (struct gendisk *hd, int part, char *buf);



extern int rescan_partitions(struct gendisk *disk, struct block_device *bdev);
@@ -553,7 +553,7 @@ static inline struct block_device *bdget_disk(struct gendisk *disk, int index) 


static inline void printk_all_partitions(void) { }



static inline dev_t blk_lookup_devt(const char *name)

static inline dev_t blk_lookup_devt(const char *name, int part)

{

	dev_t devt = MKDEV(0, 0);

	return devt;

init/do_mounts.c

+26 −1
Original line number Diff line number Diff line
@@ -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;

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