[PATCH] Re: Lost Partition

Alexander Viro (viro@math.psu.edu)
Thu, 11 Oct 2001 09:19:58 -0400 (EDT)


On Thu, 11 Oct 2001, Vincent Sweeney wrote:

> I have just upgrade my kernel to 2.4.12 and in the process I've lost a
> partition on my secondary IDE drive. Since this is my /usr partition
> it's kind of important ;)

Please, see if the following fixes the problem.

--- S11/fs/partitions/msdos.c Tue Oct 9 21:47:27 2001
+++ /tmp/msdos.c Thu Oct 11 09:18:22 2001
@@ -103,21 +103,20 @@
*/

static void extended_partition(struct gendisk *hd, struct block_device *bdev,
- int minor, int *current_minor)
+ int minor, unsigned long first_size, int *current_minor)
{
struct partition *p;
Sector sect;
unsigned char *data;
- unsigned long first_sector, first_size, this_sector, this_size;
+ unsigned long first_sector, this_sector, this_size;
int mask = (1 << hd->minor_shift) - 1;
int sector_size = get_hardsect_size(to_kdev_t(bdev->bd_dev)) / 512;
int loopct = 0; /* number of links followed
without finding a data partition */
int i;

- first_sector = hd->part[minor].start_sect;
- first_size = hd->part[minor].nr_sects;
- this_sector = first_sector;
+ this_sector = first_sector = hd->part[minor].start_sect;
+ this_size = first_size;

while (1) {
if (++loopct > 100)
@@ -133,8 +132,6 @@

p = (struct partition *) (data + 0x1be);

- this_size = hd->part[minor].nr_sects;
-
/*
* Usually, the first entry is the real data partition,
* the 2nd entry is the next extended partition, or empty,
@@ -196,6 +193,7 @@
goto done; /* nothing left to do */

this_sector = first_sector + START_SECT(p) * sector_size;
+ this_size = NR_SECTS(p) * sector_size;
minor = *current_minor;
put_dev_sector(sect);
}
@@ -586,12 +584,13 @@
}
#endif
if (is_extended_partition(p)) {
+ unsigned long size = hd->part[minor].nr_sects;
printk(" <");
/* prevent someone doing mkfs or mkswap on an
extended partition, but leave room for LILO */
- if (hd->part[minor].nr_sects > 2)
+ if (size > 2)
hd->part[minor].nr_sects = 2;
- extended_partition(hd, bdev, minor, &current_minor);
+ extended_partition(hd, bdev, minor, size, &current_minor);
printk(" >");
}
}

-
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