From 967c9a98626b1e402ab042bd770b7109532f49fb Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Fri, 31 May 2013 19:39:56 -0400 Subject: ext4: fix overflow when counting used blocks on 32-bit architectures commit 8af8eecc1331dbf5e8c662022272cf667e213da5 upstream. The arithmetics adding delalloc blocks to the number of used blocks in ext4_getattr() can easily overflow on 32-bit archs as we first multiply number of blocks by blocksize and then divide back by 512. Make the arithmetics more clever and also use proper type (unsigned long long instead of unsigned long). Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o Signed-off-by: Ben Hutchings --- fs/ext4/inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs') diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 025b4b6573d7..45778a62928c 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4335,7 +4335,7 @@ int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) { struct inode *inode; - unsigned long delalloc_blocks; + unsigned long long delalloc_blocks; inode = dentry->d_inode; generic_fillattr(inode, stat); @@ -4352,7 +4352,7 @@ int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry, */ delalloc_blocks = EXT4_I(inode)->i_reserved_data_blocks; - stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9; + stat->blocks += delalloc_blocks << (inode->i_sb->s_blocksize_bits-9); return 0; } -- cgit v1.2.3