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

/*
 *  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
 */

#define NFS_NEED_XDR_TYPES
#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/slab.h>
#include <linux/string.h>
#include <linux/smp_lock.h>
#include <linux/namei.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;

	lock_kernel();
	error = NFS_PROTO(inode)->readlink(inode, page, 0, PAGE_SIZE);
	unlock_kernel();
	if (error < 0)
		goto error;
	SetPageUptodate(page);
	unlock_page(page);
	return 0;

error:
	SetPageError(page);
	unlock_page(page);
	return -EIO;
}

static void *nfs_follow_link(struct dentry *dentry, struct nameidata *nd)
{
	struct inode *inode = dentry->d_inode;
	struct page *page;
	void *err = ERR_PTR(nfs_revalidate_inode(NFS_SERVER(inode), inode));
	if (err)
		goto read_failed;
	page = read_cache_page(&inode->i_data, 0,
				(filler_t *)nfs_symlink_filler, inode);
	if (IS_ERR(page)) {
		err = page;
		goto read_failed;
	}
	if (!PageUptodate(page)) {
		err = ERR_PTR(-EIO);
		goto getlink_read_error;
	}
	nd_set_link(nd, kmap(page));
	return page;

getlink_read_error:
	page_cache_release(page);
read_failed:
	nd_set_link(nd, err);
	return NULL;
}

static void nfs_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
{
	if (cookie) {
		struct page *page = cookie;
		kunmap(page);
		page_cache_release(page);
	}
}

/*
 * symlinks can't do much...
 */
struct inode_operations nfs_symlink_inode_operations = {
	.readlink	= generic_readlink,
	.follow_link	= nfs_follow_link,
	.put_link	= nfs_put_link,
	.getattr	= nfs_getattr,
	.setattr	= nfs_setattr,
};
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/nfs/symlink.c
	3	*
	4	* Copyright (C) 1992 Rick Sladkey
	5	*
	6	* Optimization changes Copyright (C) 1994 Florian La Roche
	7	*
	8	* Jun 7 1999, cache symlink lookups in the page cache. -DaveM
	9	*
	10	* nfs symlink handling code
	11	*/
	12
	13	#define NFS_NEED_XDR_TYPES
	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>
	23	#include <linux/slab.h>
	24	#include <linux/string.h>
	25	#include <linux/smp_lock.h>
	26	#include <linux/namei.h>
	27
	28	/* Symlink caching in the page cache is even more simplistic
	29	* and straight-forward than readdir caching.
1da177e4 LT	30	*/
1da177e4 LT	31
1da177e4 LT	32	static int nfs_symlink_filler(struct inode inode, struct page page)
1da177e4 LT	33	{
1da177e4 LT	34	int error;
	35
	36	lock_kernel();
cc314eef	37	error = NFS_PROTO(inode)->readlink(inode, page, 0, PAGE_SIZE);
1da177e4 LT	38	unlock_kernel();
	39	if (error < 0)
	40	goto error;
	41	SetPageUptodate(page);
	42	unlock_page(page);
	43	return 0;
	44
	45	error:
	46	SetPageError(page);
	47	unlock_page(page);
	48	return -EIO;
	49	}
	50
cc314eef	51	static void nfs_follow_link(struct dentry dentry, struct nameidata *nd)
1da177e4 LT	52	{
	53	struct inode *inode = dentry->d_inode;
	54	struct page *page;
1da177e4 LT	55	void *err = ERR_PTR(nfs_revalidate_inode(NFS_SERVER(inode), inode));
	56	if (err)
	57	goto read_failed;
	58	page = read_cache_page(&inode->i_data, 0,
	59	(filler_t *)nfs_symlink_filler, inode);
	60	if (IS_ERR(page)) {
	61	err = page;
	62	goto read_failed;
	63	}
	64	if (!PageUptodate(page)) {
	65	err = ERR_PTR(-EIO);
	66	goto getlink_read_error;
	67	}
cc314eef LT	68	nd_set_link(nd, kmap(page));
cc314eef LT	69	return page;
1da177e4 LT	70
	71	getlink_read_error:
	72	page_cache_release(page);
	73	read_failed:
	74	nd_set_link(nd, err);
cc314eef	75	return NULL;
1da177e4 LT	76	}
1da177e4 LT	77
cc314eef	78	static void nfs_put_link(struct dentry dentry, struct nameidata nd, void *cookie)
1da177e4	79	{
cc314eef LT	80	if (cookie) {
cc314eef LT	81	struct page *page = cookie;
1da177e4 LT	82	kunmap(page);
	83	page_cache_release(page);
	84	}
	85	}
	86
	87	/*
	88	* symlinks can't do much...
	89	*/
	90	struct inode_operations nfs_symlink_inode_operations = {
	91	.readlink = generic_readlink,
	92	.follow_link = nfs_follow_link,
	93	.put_link = nfs_put_link,
	94	.getattr = nfs_getattr,
	95	.setattr = nfs_setattr,
	96	};