1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (c) 2015, Primary Data, Inc. All rights reserved. 4 * 5 * Tao Peng <bergwolf@primarydata.com> 6 */ 7 #include <linux/dcache.h> 8 #include <linux/exportfs.h> 9 #include <linux/nfs.h> 10 #include <linux/nfs_fs.h> 11 12 #include "internal.h" 13 #include "nfstrace.h" 14 15 #define NFSDBG_FACILITY NFSDBG_VFS 16 17 enum { 18 FILEID_HIGH_OFF = 0, /* inode fileid high */ 19 FILEID_LOW_OFF, /* inode fileid low */ 20 FILE_I_TYPE_OFF, /* inode type */ 21 EMBED_FH_OFF /* embeded server fh */ 22 }; 23 24 25 static struct nfs_fh *nfs_exp_embedfh(__u32 *p) 26 { 27 return (struct nfs_fh *)(p + EMBED_FH_OFF); 28 } 29 30 /* 31 * Let's break subtree checking for now... otherwise we'll have to embed parent fh 32 * but there might not be enough space. 33 */ 34 static int 35 nfs_encode_fh(struct inode *inode, __u32 *p, int *max_len, struct inode *parent) 36 { 37 struct nfs_fh *server_fh = NFS_FH(inode); 38 struct nfs_fh *clnt_fh = nfs_exp_embedfh(p); 39 size_t fh_size = offsetof(struct nfs_fh, data) + server_fh->size; 40 int len = EMBED_FH_OFF + XDR_QUADLEN(fh_size); 41 42 dprintk("%s: max fh len %d inode %p parent %p", 43 __func__, *max_len, inode, parent); 44 45 if (*max_len < len || IS_AUTOMOUNT(inode)) { 46 dprintk("%s: fh len %d too small, required %d\n", 47 __func__, *max_len, len); 48 *max_len = len; 49 return FILEID_INVALID; 50 } 51 if (IS_AUTOMOUNT(inode)) { 52 *max_len = FILEID_INVALID; 53 goto out; 54 } 55 56 p[FILEID_HIGH_OFF] = NFS_FILEID(inode) >> 32; 57 p[FILEID_LOW_OFF] = NFS_FILEID(inode); 58 p[FILE_I_TYPE_OFF] = inode->i_mode & S_IFMT; 59 p[len - 1] = 0; /* Padding */ 60 nfs_copy_fh(clnt_fh, server_fh); 61 *max_len = len; 62 out: 63 dprintk("%s: result fh fileid %llu mode %u size %d\n", 64 __func__, NFS_FILEID(inode), inode->i_mode, *max_len); 65 return *max_len; 66 } 67 68 static struct dentry * 69 nfs_fh_to_dentry(struct super_block *sb, struct fid *fid, 70 int fh_len, int fh_type) 71 { 72 struct nfs4_label *label = NULL; 73 struct nfs_fattr *fattr = NULL; 74 struct nfs_fh *server_fh = nfs_exp_embedfh(fid->raw); 75 size_t fh_size = offsetof(struct nfs_fh, data) + server_fh->size; 76 const struct nfs_rpc_ops *rpc_ops; 77 struct dentry *dentry; 78 struct inode *inode; 79 int len = EMBED_FH_OFF + XDR_QUADLEN(fh_size); 80 u32 *p = fid->raw; 81 int ret; 82 83 /* NULL translates to ESTALE */ 84 if (fh_len < len || fh_type != len) 85 return NULL; 86 87 fattr = nfs_alloc_fattr(); 88 if (fattr == NULL) { 89 dentry = ERR_PTR(-ENOMEM); 90 goto out; 91 } 92 93 fattr->fileid = ((u64)p[FILEID_HIGH_OFF] << 32) + p[FILEID_LOW_OFF]; 94 fattr->mode = p[FILE_I_TYPE_OFF]; 95 fattr->valid |= NFS_ATTR_FATTR_FILEID | NFS_ATTR_FATTR_TYPE; 96 97 dprintk("%s: fileid %llu mode %d\n", __func__, fattr->fileid, fattr->mode); 98 99 inode = nfs_ilookup(sb, fattr, server_fh); 100 if (inode) 101 goto out_found; 102 103 label = nfs4_label_alloc(NFS_SB(sb), GFP_KERNEL); 104 if (IS_ERR(label)) { 105 dentry = ERR_CAST(label); 106 goto out_free_fattr; 107 } 108 109 rpc_ops = NFS_SB(sb)->nfs_client->rpc_ops; 110 ret = rpc_ops->getattr(NFS_SB(sb), server_fh, fattr, label); 111 if (ret) { 112 dprintk("%s: getattr failed %d\n", __func__, ret); 113 dentry = ERR_PTR(ret); 114 goto out_free_label; 115 } 116 117 inode = nfs_fhget(sb, server_fh, fattr, label); 118 119 out_found: 120 dentry = d_obtain_alias(inode); 121 122 out_free_label: 123 nfs4_label_free(label); 124 out_free_fattr: 125 nfs_free_fattr(fattr); 126 out: 127 return dentry; 128 } 129 130 static struct dentry * 131 nfs_get_parent(struct dentry *dentry) 132 { 133 int ret; 134 struct inode *inode = d_inode(dentry), *pinode; 135 struct super_block *sb = inode->i_sb; 136 struct nfs_server *server = NFS_SB(sb); 137 struct nfs_fattr *fattr = NULL; 138 struct nfs4_label *label = NULL; 139 struct dentry *parent; 140 struct nfs_rpc_ops const *ops = server->nfs_client->rpc_ops; 141 struct nfs_fh fh; 142 143 if (!ops->lookupp) 144 return ERR_PTR(-EACCES); 145 146 fattr = nfs_alloc_fattr(); 147 if (fattr == NULL) { 148 parent = ERR_PTR(-ENOMEM); 149 goto out; 150 } 151 152 label = nfs4_label_alloc(server, GFP_KERNEL); 153 if (IS_ERR(label)) { 154 parent = ERR_CAST(label); 155 goto out_free_fattr; 156 } 157 158 ret = ops->lookupp(inode, &fh, fattr, label); 159 if (ret) { 160 parent = ERR_PTR(ret); 161 goto out_free_label; 162 } 163 164 pinode = nfs_fhget(sb, &fh, fattr, label); 165 parent = d_obtain_alias(pinode); 166 out_free_label: 167 nfs4_label_free(label); 168 out_free_fattr: 169 nfs_free_fattr(fattr); 170 out: 171 return parent; 172 } 173 174 const struct export_operations nfs_export_ops = { 175 .encode_fh = nfs_encode_fh, 176 .fh_to_dentry = nfs_fh_to_dentry, 177 .get_parent = nfs_get_parent, 178 }; 179