On Thu, 28 Feb 2008 13:32:01 +0100 Frank Seidel <fseidel@xxxxxxx> wrote: > Most fat formatted media without partition table contains > zeros in the boot indication and the other tested bytes > and so falls through the checks in msdos_partition, leading > it to return with 1 (all is fine). > But some (e.g. WinXP formatted) fat fomated medias don't > use boot_ind and so the check fails and causes a > "unkown partition table" warning eventhough there is none > and everything would be fine. > This additional check directly verifies if there is a > fat formatted medium without a partition table. > > Signed-off-by: Frank Seidel <fseidel@xxxxxxx> > --- > fs/partitions/msdos.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > --- a/fs/partitions/msdos.c > +++ b/fs/partitions/msdos.c > @@ -18,7 +18,7 @@ > * > * Re-organised Feb 1998 Russell King > */ > - > +#include <linux/msdos_fs.h> > > #include "check.h" > #include "msdos.h" > @@ -419,6 +419,7 @@ int msdos_partition(struct parsed_partit > Sector sect; > unsigned char *data; > struct partition *p; > + struct fat_boot_sector *fb; > int slot; > > data = read_dev_sector(bdev, 0, §); > @@ -441,6 +442,12 @@ int msdos_partition(struct parsed_partit > * partition table. Reject this in case the boot indicator > * is not 0 or 0x80. > */ > + fb = (struct fat_boot_sector *) data; > + if (fb->reserved && fb->fats && FAT_VALID_MEDIA(fb->media)) { > + printk("\n"); > + put_dev_sector(sect); > + return 1; > + } > p = (struct partition *) (data + 0x1be); > for (slot = 1; slot <= 4; slot++, p++) { > if (p->boot_ind != 0 && p->boot_ind != 0x80) { fs/partitions/msdos.c: In function 'msdos_partition': fs/partitions/msdos.c:446: warning: comparison is always true due to limited range of data type didn't you get this? The reason is that FAT_VALID_MEDIA() is bogus: #define FAT_VALID_MEDIA(x) ((0xF8 <= (x) && (x) <= 0xFF) || (x) == 0xF0) It appears that the on-disk field which FAT_VALID_MEDIA() is designed to test is only 8-bit, so the comparison with 0xff is pointless. The only existing caller of FAT_VALID_MEDIA() cheats by copying the value into a local unsigned int first. So I'll leave things as they are for now, but I'd ask that someone can confirm that we should simply remove the 0xff test from FAT_VALID_MEDIA()? -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html