ext4: Widen type of ext4_sb_info.s_mb_maxs[]

I chased the cause of following ext4 oops report which is tested on
ia64 box.

http://bugzilla.kernel.org/show_bug.cgi?id=12018

The cause is the size of s_mb_maxs array that is defined as "unsigned
short" in ext4_sb_info structure.  If the file system's block size is
8k or greater, an unsigned short is not wide enough to contain the
value fs->blocksize << 3.

Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Miao Xie <miaox@cn.fujitsu.com>
Cc: stable@kernel.org

2 files changed, 4 insertions, 1 deletions

diff --git a/fs/ext4/ext4_sb.h b/fs/ext4/ext4_sb.h
index ad7ea09baa72..3db800f399a6 100644
--- a/fs/ext4/ext4_sb.h
+++ b/fs/ext4/ext4_sb.h
@@ -102,7 +102,8 @@ struct ext4_sb_info {
         spinlock_t s_reserve_lock;
         spinlock_t s_md_lock;
         tid_t s_last_transaction;
-        unsigned short *s_mb_offsets, *s_mb_maxs;
+        unsigned short *s_mb_offsets;
+        unsigned int *s_mb_maxs;
 
         /* tunables */
         unsigned long s_stripe;
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 444ad998f72e..7beab7141dd5 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2493,6 +2493,8 @@ int ext4_mb_init(struct super_block *sb, int needs_recovery)
         if (sbi->s_mb_offsets == NULL) {
                 return -ENOMEM;
         }
+
+        i = (sb->s_blocksize_bits + 2) * sizeof(unsigned int);
         sbi->s_mb_maxs = kmalloc(i, GFP_KERNEL);
         if (sbi->s_mb_maxs == NULL) {
                 kfree(sbi->s_mb_maxs);