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-rw-r--r--fs/nfs/symlink.c85
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,
+};