[linux.git] / fs / nfs / symlink.c

// 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 inode *inode, struct page *page)
{
	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,
					(filler_t *)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,
};
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* linux/fs/nfs/symlink.c
	4	*
	5	* Copyright (C) 1992 Rick Sladkey
	6	*
	7	* Optimization changes Copyright (C) 1994 Florian La Roche
	8	*
	9	* Jun 7 1999, cache symlink lookups in the page cache. -DaveM
	10	*
	11	* nfs symlink handling code
	12	*/
	13
1da177e4 LT	14	#include <linux/time.h>
	15	#include <linux/errno.h>
	16	#include <linux/sunrpc/clnt.h>
	17	#include <linux/nfs.h>
	18	#include <linux/nfs2.h>
	19	#include <linux/nfs_fs.h>
	20	#include <linux/pagemap.h>
	21	#include <linux/stat.h>
	22	#include <linux/mm.h>
1da177e4	23	#include <linux/string.h>
1da177e4 LT	24
	25	/* Symlink caching in the page cache is even more simplistic
	26	* and straight-forward than readdir caching.
1da177e4 LT	27	*/
1da177e4 LT	28
1da177e4 LT	29	static int nfs_symlink_filler(struct inode inode, struct page page)
1da177e4 LT	30	{
1da177e4 LT	31	int error;
1da177e4 LT	32
cc314eef	33	error = NFS_PROTO(inode)->readlink(inode, page, 0, PAGE_SIZE);
1da177e4 LT	34	if (error < 0)
	35	goto error;
	36	SetPageUptodate(page);
	37	unlock_page(page);
	38	return 0;
	39
	40	error:
	41	SetPageError(page);
	42	unlock_page(page);
	43	return -EIO;
	44	}
	45
6b255391	46	static const char nfs_get_link(struct dentry dentry,
fceef393 AV	47	struct inode *inode,
fceef393 AV	48	struct delayed_call *done)
1da177e4	49	{
1da177e4	50	struct page *page;
717d44e8 TM	51	void *err;
717d44e8 TM	52
0d0def49 AV	53	if (!dentry) {
	54	err = ERR_PTR(nfs_revalidate_mapping_rcu(inode));
	55	if (err)
	56	return err;
	57	page = find_get_page(inode->i_mapping, 0);
	58	if (!page)
	59	return ERR_PTR(-ECHILD);
	60	if (!PageUptodate(page)) {
	61	put_page(page);
	62	return ERR_PTR(-ECHILD);
	63	}
	64	} else {
	65	err = ERR_PTR(nfs_revalidate_mapping(inode, inode->i_mapping));
	66	if (err)
	67	return err;
	68	page = read_cache_page(&inode->i_data, 0,
	69	(filler_t *)nfs_symlink_filler, inode);
	70	if (IS_ERR(page))
	71	return ERR_CAST(page);
	72	}
fceef393	73	set_delayed_call(done, page_put_link, page);
21fc61c7	74	return page_address(page);
1da177e4 LT	75	}
1da177e4 LT	76
1da177e4 LT	77	/*
	78	* symlinks can't do much...
	79	*/
92e1d5be	80	const struct inode_operations nfs_symlink_inode_operations = {
6b255391	81	.get_link = nfs_get_link,
1da177e4 LT	82	.getattr = nfs_getattr,
	83	.setattr = nfs_setattr,
	84	};