+/*
+ * Prevent concurrent writepages on inode
+ *
+ * This is done by adding a negative bias to the inode write counter
+ * and waiting for all pending writes to finish.
+ */
+void fuse_set_nowrite(struct inode *inode)
+{
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_inode *fi = get_fuse_inode(inode);
+
+ BUG_ON(!mutex_is_locked(&inode->i_mutex));
+
+ spin_lock(&fc->lock);
+ BUG_ON(fi->writectr < 0);
+ fi->writectr += FUSE_NOWRITE;
+ spin_unlock(&fc->lock);
+ wait_event(fi->page_waitq, fi->writectr == FUSE_NOWRITE);
+}
+
+/*
+ * Allow writepages on inode
+ *
+ * Remove the bias from the writecounter and send any queued
+ * writepages.
+ */
+static void __fuse_release_nowrite(struct inode *inode)
+{
+ struct fuse_inode *fi = get_fuse_inode(inode);
+
+ BUG_ON(fi->writectr != FUSE_NOWRITE);
+ fi->writectr = 0;
+ fuse_flush_writepages(inode);
+}
+
+void fuse_release_nowrite(struct inode *inode)
+{
+ struct fuse_conn *fc = get_fuse_conn(inode);
+
+ spin_lock(&fc->lock);
+ __fuse_release_nowrite(inode);
+ spin_unlock(&fc->lock);
+}
+