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#include <linux/time.h> 14#include <linux/errno.h> 15#include <linux/sunrpc/clnt.h> 16#include <linux/nfs.h> 17#include <linux/nfs2.h> 18#include <linux/nfs_fs.h> 19#include <linux/pagemap.h> 20#include <linux/stat.h> 21#include <linux/mm.h> 22#include <linux/string.h> 23#include <linux/namei.h> 24 25/* Symlink caching in the page cache is even more simplistic 26 * and straight-forward than readdir caching. 27 */ 28 29static int nfs_symlink_filler(struct inode *inode, struct page *page) 30{ 31 int error; 32 33 error = NFS_PROTO(inode)->readlink(inode, page, 0, PAGE_SIZE); 34 if (error < 0) 35 goto error; 36 SetPageUptodate(page); 37 unlock_page(page); 38 return 0; 39 40error: 41 SetPageError(page); 42 unlock_page(page); 43 return -EIO; 44} 45 46static void *nfs_follow_link(struct dentry *dentry, struct nameidata *nd) 47{ 48 struct inode *inode = dentry->d_inode; 49 struct page *page; 50 void *err; 51 52 err = ERR_PTR(nfs_revalidate_mapping(inode, inode->i_mapping)); 53 if (err) 54 goto read_failed; 55 page = read_cache_page(&inode->i_data, 0, 56 (filler_t *)nfs_symlink_filler, inode); 57 if (IS_ERR(page)) { 58 err = page; 59 goto read_failed; 60 } 61 nd_set_link(nd, kmap(page)); 62 return page; 63 64read_failed: 65 nd_set_link(nd, err); 66 return NULL; 67} 68 69/* 70 * symlinks can't do much... 71 */ 72const struct inode_operations nfs_symlink_inode_operations = { 73 .readlink = generic_readlink, 74 .follow_link = nfs_follow_link, 75 .put_link = page_put_link, 76 .getattr = nfs_getattr, 77 .setattr = nfs_setattr, 78}; 79