[PATCH] fat/inode.c

Two years ago, OGAWA Hirofumi removed some ugly code and
added a few simple tests to the FAT filesystem code,
intended to avoid recognizing non-FAT as FAT (for people who
fail to specify rootfstype=, forcing the kernel to guess).

That worked fairly well, until this year.

I have now seen a thread in Czech and a report from Holland that
involved the "FAT: bogus sectors-per-track value" error message.

The patch below removes this test again. The advantage is that
some real-life FAT filesystems can be mounted again.

The disadvantage that more non-FAT fss will be accepted as FAT.

Ferry van Steen <freaky@bananateam.nl> reports "the patch Andries
Brouwer gave me seems to work".
Signed-off-by: Andries Brouwer <aeb@cwi.nl>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/fat/inode.c

@@ -843,18 +843,12 @@ int fat_fill_super(struct super_block *sb, void *data, int silent,
 		brelse(bh);
 		goto out_invalid;
 	}
-	if (!b->secs_track) {
-		if (!silent)
-			printk(KERN_ERR "FAT: bogus sectors-per-track value\n");
-		brelse(bh);
-		goto out_invalid;
-	}
-	if (!b->heads) {
-		if (!silent)
-			printk(KERN_ERR "FAT: bogus number-of-heads value\n");
-		brelse(bh);
-		goto out_invalid;
-	}
+
+	/*
+	 * Earlier we checked here that b->secs_track and b->head are nonzero,
+	 * but it turns out valid FAT filesystems can have zero there.
+	 */
+
 	media = b->media;
 	if (!FAT_VALID_MEDIA(media)) {
 		if (!silent)