/* * 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, };