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List:       linux-ide
Subject:    [PATCH] ide-floppy: Fix unformatted media crash
From:       Alan <alan () lxorguk ! ukuu ! org ! uk>
Date:       2007-01-31 17:41:23
Message-ID: 20070131174123.17aba9d1 () localhost ! localdomain
[Download RAW message or body]

A ZIP or similar with unformatted media will cause crashes when attempts
are made to read/write it in some cases. This is because bs_factor is
zero and we divide by it causing an oops.

As the size of a non-accessible/non-existant media is really a bit of a
zen question it doesn't matter if non-existant media is 512 bytes per
sector or zero. Setting it to 1 causes us to generate 512 bytes/sector
accesses and error properly.

Signed-off-by: Alan Cox <alan@redhat.com>

Based on a fix found lurking in an ancient bugzilla entry since about 2004 (ugghhh)

diff -u --new-file --recursive --exclude-from /usr/src/exclude \
linux.vanilla-2.6.20-rc6-mm3/drivers/ide/ide-floppy.c \
                linux-2.6.20-rc6-mm3/drivers/ide/ide-floppy.c
--- linux.vanilla-2.6.20-rc6-mm3/drivers/ide/ide-floppy.c	2007-01-31 \
                14:20:40.000000000 +0000
+++ linux-2.6.20-rc6-mm3/drivers/ide/ide-floppy.c	2007-01-31 14:33:42.000000000 +0000
@@ -1434,7 +1434,8 @@
 	
 	drive->bios_cyl = 0;
 	drive->bios_head = drive->bios_sect = 0;
-	floppy->blocks = floppy->bs_factor = 0;
+	floppy->blocks = 0;
+	floppy->bs_factor = 1;
 	set_capacity(floppy->disk, 0);
 
 	idefloppy_create_read_capacity_cmd(&pc);

-
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