ext4: fix mmap data corruption when blocksize < pagesize

commit d6320cbfc92910a3e5f10c42d98c231c98db4f60 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index b56062d..6b6e8c5 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4645,8 +4645,12 @@ 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