+static int __ocfs2_page_mkwrite(struct inode *inode, struct buffer_head *di_bh,
+ struct page *page)
+{
+ int ret;
+ struct address_space *mapping = inode->i_mapping;
+ loff_t pos = page->index << PAGE_CACHE_SHIFT;
+ unsigned int len = PAGE_CACHE_SIZE;
+ pgoff_t last_index;
+ struct page *locked_page = NULL;
+ void *fsdata;
+ loff_t size = i_size_read(inode);
+
+ /*
+ * Another node might have truncated while we were waiting on
+ * cluster locks.
+ */
+ last_index = size >> PAGE_CACHE_SHIFT;
+ if (page->index > last_index) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /*
+ * The i_size check above doesn't catch the case where nodes
+ * truncated and then re-extended the file. We'll re-check the
+ * page mapping after taking the page lock inside of
+ * ocfs2_write_begin_nolock().
+ */
+ if (!PageUptodate(page) || page->mapping != inode->i_mapping) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /*
+ * Call ocfs2_write_begin() and ocfs2_write_end() to take
+ * advantage of the allocation code there. We pass a write
+ * length of the whole page (chopped to i_size) to make sure
+ * the whole thing is allocated.
+ *
+ * Since we know the page is up to date, we don't have to
+ * worry about ocfs2_write_begin() skipping some buffer reads
+ * because the "write" would invalidate their data.
+ */
+ if (page->index == last_index)
+ len = size & ~PAGE_CACHE_MASK;
+
+ ret = ocfs2_write_begin_nolock(mapping, pos, len, 0, &locked_page,
+ &fsdata, di_bh, page);
+ if (ret) {
+ if (ret != -ENOSPC)
+ mlog_errno(ret);
+ goto out;
+ }
+
+ ret = ocfs2_write_end_nolock(mapping, pos, len, len, locked_page,
+ fsdata);
+ if (ret < 0) {
+ mlog_errno(ret);
+ goto out;
+ }
+ BUG_ON(ret != len);
+ ret = 0;
+out:
+ return ret;
+}
+
+static int ocfs2_page_mkwrite(struct vm_area_struct *vma, struct page *page)
+{
+ struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
+ struct buffer_head *di_bh = NULL;
+ sigset_t blocked, oldset;
+ int ret, ret2;
+
+ ret = ocfs2_vm_op_block_sigs(&blocked, &oldset);
+ if (ret < 0) {
+ mlog_errno(ret);
+ return ret;
+ }
+
+ /*
+ * The cluster locks taken will block a truncate from another
+ * node. Taking the data lock will also ensure that we don't
+ * attempt page truncation as part of a downconvert.
+ */
+ ret = ocfs2_meta_lock(inode, &di_bh, 1);
+ if (ret < 0) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ /*
+ * The alloc sem should be enough to serialize with
+ * ocfs2_truncate_file() changing i_size as well as any thread
+ * modifying the inode btree.
+ */
+ down_write(&OCFS2_I(inode)->ip_alloc_sem);
+
+ ret = ocfs2_data_lock(inode, 1);
+ if (ret < 0) {
+ mlog_errno(ret);
+ goto out_meta_unlock;
+ }
+
+ ret = __ocfs2_page_mkwrite(inode, di_bh, page);
+
+ ocfs2_data_unlock(inode, 1);
+
+out_meta_unlock:
+ up_write(&OCFS2_I(inode)->ip_alloc_sem);
+
+ brelse(di_bh);
+ ocfs2_meta_unlock(inode, 1);
+
+out:
+ ret2 = ocfs2_vm_op_unblock_sigs(&oldset);
+ if (ret2 < 0)
+ mlog_errno(ret2);
+
+ return ret;
+}
+