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// 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(void *data, struct page *page)
{
struct inode *inode = data;
int error;
error = NFS_PROTO(inode)->readlink(inode, page, 0, PAGE_SIZE);
if (error < 0)
goto error;
SetPageUptodate(page);
unlock_page(page);
return 0;
error:
SetPageError(page);
unlock_page(page);
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,
inode);
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,
};
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