Attachment 198218 Details for Bug 364365

[patch] patch v2

mypartfixup2.patch (text/plain), 2.33 KB, created by Frank Seidel on 2008-03-03 10:57:11 UTC

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Creator: Frank Seidel

Created: 2008-03-03 10:57:11 UTC

Size: 2.33 KB

patch

obsolete

>Subject: fat: detect media without partition table correctly
>From: Frank Seidel <fseidel@suse.de>
>
>I received a complaint that some FAT formated medias
>(e.g. sd memory cards) trigger a "unknown partition table" message even though
>there is no partition table and they work correctly, while in general
>(when e.g. formated with mkdosfs or even Windows Vista) this message is not
>shown.
>
>Currently this seems only to happen when the medias get formatted with
>Windows XP (and possibly Win 2000). Then the boot indicator byte contains
>garbage (part of text message) and so do the other parts checked by
>msdos_paritition which then later triggers this message.
>
>References: novell bug #364365
>
>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@suse.de>
>Cc: Andreas Dilger <adilger@sun.com>
>Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
>Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
>---
> fs/partitions/msdos.c |   15 ++++++++++++---
> 1 file changed, 12 insertions(+), 3 deletions(-)
>
>--- 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, &sect);
>@@ -444,8 +445,16 @@ int msdos_partition(struct parsed_partit
> 	p = (struct partition *) (data + 0x1be);
> 	for (slot = 1; slot <= 4; slot++, p++) {
> 		if (p->boot_ind != 0 && p->boot_ind != 0x80) {
>-			put_dev_sector(sect);
>-			return 0;
>+			fb = (struct fat_boot_sector *) data;
>+			if (slot == 1 && fb->reserved && fb->fats
>+				&& fat_valid_media(fb->media)) {
>+				printk("\n");
>+				put_dev_sector(sect);
>+				return 1;
>+			} else {
>+				put_dev_sector(sect);
>+				return 0;
>+			}
> 		}
> 	}
>

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