ext4: fix mmap data corruption when blocksize < pagesize

Use truncate_isize_extended() when hole is being created in a file so that
->page_mkwrite() will get called for the partial tail page if it is
mmaped (see the first patch in the series for details).

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index d5dd7d4..0918452 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4514,8 +4514,12 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
                                ext4_orphan_del(NULL, inode);
                                goto err_out;
                        }
-               } else
+               } else {
+                       loff_t oldsize = inode->i_size;
+
                        i_size_write(inode, attr->ia_size);
+                       pagecache_isize_extended(inode, oldsize, inode->i_size);
+               }
 
                /*
                 * Blocks are going to be removed from the inode. Wait