1 files changed, 85 insertions, 0 deletions
diff --git a/fs/nfs/symlink.c b/fs/nfs/symlink.c
new file mode 100644
index 000000000..0e27a2e4e
--- /dev/null
+++ b/fs/nfs/symlink.c
@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/nfs/symlink.c
+ *
+ *  Copyright (C) 1992  Rick Sladkey
+ *
+ *  Optimization changes Copyright (C) 1994 Florian La Roche
+ *
+ *  Jun 7 1999, cache symlink lookups in the page cache.  -DaveM
+ *
+ *  nfs symlink handling code
+ */
+
+#include <linux/time.h>
+#include <linux/errno.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/nfs.h>
+#include <linux/nfs2.h>
+#include <linux/nfs_fs.h>
+#include <linux/pagemap.h>
+#include <linux/stat.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+
+/* Symlink caching in the page cache is even more simplistic
+ * and straight-forward than readdir caching.
+ */
+
+static int nfs_symlink_filler(struct file *file, struct folio *folio)
+{
+	struct inode *inode = folio->mapping->host;
+	int error;
+
+	error = NFS_PROTO(inode)->readlink(inode, &folio->page, 0, PAGE_SIZE);
+	if (error < 0)
+		goto error;
+	folio_mark_uptodate(folio);
+	folio_unlock(folio);
+	return 0;
+
+error:
+	folio_set_error(folio);
+	folio_unlock(folio);
+	return -EIO;
+}
+
+static const char *nfs_get_link(struct dentry *dentry,
+				struct inode *inode,
+				struct delayed_call *done)
+{
+	struct page *page;
+	void *err;
+
+	if (!dentry) {
+		err = ERR_PTR(nfs_revalidate_mapping_rcu(inode));
+		if (err)
+			return err;
+		page = find_get_page(inode->i_mapping, 0);
+		if (!page)
+			return ERR_PTR(-ECHILD);
+		if (!PageUptodate(page)) {
+			put_page(page);
+			return ERR_PTR(-ECHILD);
+		}
+	} else {
+		err = ERR_PTR(nfs_revalidate_mapping(inode, inode->i_mapping));
+		if (err)
+			return err;
+		page = read_cache_page(&inode->i_data, 0, nfs_symlink_filler,
+				NULL);
+		if (IS_ERR(page))
+			return ERR_CAST(page);
+	}
+	set_delayed_call(done, page_put_link, page);
+	return page_address(page);
+}
+
+/*
+ * symlinks can't do much...
+ */
+const struct inode_operations nfs_symlink_inode_operations = {
+	.get_link	= nfs_get_link,
+	.getattr	= nfs_getattr,
+	.setattr	= nfs_setattr,
+};