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authorJan Kara <jack@suse.cz>2013-05-31 19:39:56 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-07-21 18:21:32 -0700
commitbb39c83ce5453f7b702865d7fe5cc283689d8810 (patch)
tree97127b430dda9c8be17486654325fd5c528a2157
parentb9ea84239c8098c367680278d1daa4d69ae88719 (diff)
downloadvexpress-lsk-bb39c83ce5453f7b702865d7fe5cc283689d8810.tar.gz
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 <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/ext4/inode.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c2434f89e9e..ccbfbbb12dc 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4808,7 +4808,7 @@ 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);
@@ -4826,7 +4826,7 @@ int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
delalloc_blocks = EXT4_C2B(EXT4_SB(inode->i_sb),
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;
}