From 90ba983f6889e65a3b506b30dc606aa9d1d46cd2 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Mon, 11 Mar 2013 23:39:59 -0400 Subject: ext4: use atomic64_t for the per-flexbg free_clusters count A user who was using a 8TB+ file system and with a very large flexbg size (> 65536) could cause the atomic_t used in the struct flex_groups to overflow. This was detected by PaX security patchset: http://forums.grsecurity.net/viewtopic.php?f=3&t=3289&p=12551#p12551 This bug was introduced in commit 9f24e4208f7e, so it's been around since 2.6.30. :-( Fix this by using an atomic64_t for struct orlav_stats's free_clusters. Signed-off-by: "Theodore Ts'o" Reviewed-by: Lukas Czerner Cc: stable@vger.kernel.org --- fs/ext4/ialloc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/ext4/ialloc.c') diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index 32fd2b9075dd..6c5bb8d993fe 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -324,8 +324,8 @@ error_return: } struct orlov_stats { + __u64 free_clusters; __u32 free_inodes; - __u32 free_clusters; __u32 used_dirs; }; @@ -342,7 +342,7 @@ static void get_orlov_stats(struct super_block *sb, ext4_group_t g, if (flex_size > 1) { stats->free_inodes = atomic_read(&flex_group[g].free_inodes); - stats->free_clusters = atomic_read(&flex_group[g].free_clusters); + stats->free_clusters = atomic64_read(&flex_group[g].free_clusters); stats->used_dirs = atomic_read(&flex_group[g].used_dirs); return; } -- cgit