// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/fs/nfs/symlink.c
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*
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* Copyright (C) 1992 Rick Sladkey
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*
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* Optimization changes Copyright (C) 1994 Florian La Roche
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*
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* Jun 7 1999, cache symlink lookups in the page cache. -DaveM
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*
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* nfs symlink handling code
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*/
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#include <linux/time.h>
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#include <linux/errno.h>
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#include <linux/sunrpc/clnt.h>
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#include <linux/nfs.h>
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#include <linux/nfs2.h>
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#include <linux/nfs_fs.h>
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#include <linux/pagemap.h>
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#include <linux/stat.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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/* Symlink caching in the page cache is even more simplistic
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* and straight-forward than readdir caching.
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*/
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static int nfs_symlink_filler(void *data, struct page *page)
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{
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struct inode *inode = data;
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int error;
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error = NFS_PROTO(inode)->readlink(inode, page, 0, PAGE_SIZE);
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if (error < 0)
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goto error;
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SetPageUptodate(page);
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unlock_page(page);
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return 0;
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error:
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SetPageError(page);
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unlock_page(page);
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return -EIO;
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}
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static const char *nfs_get_link(struct dentry *dentry,
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struct inode *inode,
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struct delayed_call *done)
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{
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struct page *page;
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void *err;
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if (!dentry) {
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err = ERR_PTR(nfs_revalidate_mapping_rcu(inode));
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if (err)
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return err;
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page = find_get_page(inode->i_mapping, 0);
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if (!page)
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return ERR_PTR(-ECHILD);
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if (!PageUptodate(page)) {
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put_page(page);
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return ERR_PTR(-ECHILD);
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}
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} else {
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err = ERR_PTR(nfs_revalidate_mapping(inode, inode->i_mapping));
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if (err)
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return err;
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page = read_cache_page(&inode->i_data, 0, nfs_symlink_filler,
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inode);
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if (IS_ERR(page))
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return ERR_CAST(page);
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}
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set_delayed_call(done, page_put_link, page);
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return page_address(page);
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}
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/*
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* symlinks can't do much...
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*/
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const struct inode_operations nfs_symlink_inode_operations = {
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.get_link = nfs_get_link,
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.getattr = nfs_getattr,
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.setattr = nfs_setattr,
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};
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