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

1 files changed, 5 insertions, 1 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index d5dd7d46844e..091845298f48 100644
--- 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