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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 | /* * 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> /* 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; /* We place the length at the beginning of the page, * in host byte order, followed by the string. The * XDR response verification will NULL terminate it. */ lock_kernel(); error = NFS_PROTO(inode)->readlink(inode, page); unlock_kernel(); if (error < 0) goto error; SetPageUptodate(page); unlock_page(page); return 0; error: SetPageError(page); unlock_page(page); return -EIO; } static char *nfs_getlink(struct inode *inode, struct page **ppage) { struct page *page; u32 *p; page = ERR_PTR(nfs_revalidate_inode(NFS_SERVER(inode), inode)); if (page) goto read_failed; page = read_cache_page(&inode->i_data, 0, (filler_t *)nfs_symlink_filler, inode); if (IS_ERR(page)) goto read_failed; if (!PageUptodate(page)) goto getlink_read_error; *ppage = page; p = kmap(page); return (char*)(p+1); getlink_read_error: page_cache_release(page); page = ERR_PTR(-EIO); read_failed: return (char*)page; } static int nfs_readlink(struct dentry *dentry, char __user *buffer, int buflen) { struct inode *inode = dentry->d_inode; struct page *page = NULL; int res = vfs_readlink(dentry,buffer,buflen,nfs_getlink(inode,&page)); if (page) { kunmap(page); page_cache_release(page); } return res; } static int nfs_follow_link(struct dentry *dentry, struct nameidata *nd) { struct inode *inode = dentry->d_inode; struct page *page = NULL; int res = vfs_follow_link(nd, nfs_getlink(inode,&page)); if (page) { kunmap(page); page_cache_release(page); } return res; } /* * symlinks can't do much... */ struct inode_operations nfs_symlink_inode_operations = { .readlink = nfs_readlink, .follow_link = nfs_follow_link, .getattr = nfs_getattr, .setattr = nfs_setattr, }; |