| 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 | |
| 29 | static 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 | |
| 40 | error: |
| 41 | SetPageError(page); |
| 42 | unlock_page(page); |
| 43 | return -EIO; |
| 44 | } |
| 45 | |
| 46 | static 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 | |
| 64 | read_failed: |
| 65 | nd_set_link(nd, err); |
| 66 | return NULL; |
| 67 | } |
| 68 | |
| 69 | /* |
| 70 | * symlinks can't do much... |
| 71 | */ |
| 72 | const 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 | }; |