From 8b9d96666529a979acf4825391efcc7c8a3e9f12 Mon Sep 17 00:00:00 2001 From: Heinz Mauelshagen Date: Wed, 12 Mar 2014 00:40:05 +0100 Subject: [PATCH] dm cache: fix truncation bug when copying a block to/from >2TB fast device During demotion or promotion to a cache's >2TB fast device we must not truncate the cache block's associated sector to 32bits. The 32bit temporary result of from_cblock() caused a 32bit multiplication when calculating the sector of the fast device in issue_copy_real(). Use an intermediate 64bit type to store the 32bit from_cblock() to allow for proper 64bit multiplication. Here is an example of how this bug manifests on an ext4 filesystem: EXT4-fs error (device dm-0): ext4_mb_generate_buddy:756: group 17136, 32768 clusters in bitmap, 30688 in gd; block bitmap corrupt. JBD2: Spotted dirty metadata buffer (dev = dm-0, blocknr = 0). There's a risk of filesystem corruption in case of system crash. Signed-off-by: Heinz Mauelshagen Acked-by: Joe Thornber Signed-off-by: Mike Snitzer Cc: stable@vger.kernel.org --- Reading git-format-patch failed