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) { 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 52 p[FILEID_HIGH_OFF] = NFS_FILEID(inode) >> 32; 53 p[FILEID_LOW_OFF] = NFS_FILEID(inode); 54 p[FILE_I_TYPE_OFF] = inode->i_mode & S_IFMT; 55 p[len - 1] = 0; /* Padding */ 56 nfs_copy_fh(clnt_fh, server_fh); 57 *max_len = len; 58 dprintk("%s: result fh fileid %llu mode %u size %d\n", 59 __func__, NFS_FILEID(inode), inode->i_mode, *max_len); 60 return *max_len; 61 } 62 63 static struct dentry * 64 nfs_fh_to_dentry(struct super_block *sb, struct fid *fid, 65 int fh_len, int fh_type) 66 { 67 struct nfs_fattr *fattr = NULL; 68 struct nfs_fh *server_fh = nfs_exp_embedfh(fid->raw); 69 size_t fh_size = offsetof(struct nfs_fh, data) + server_fh->size; 70 const struct nfs_rpc_ops *rpc_ops; 71 struct dentry *dentry; 72 struct inode *inode; 73 int len = EMBED_FH_OFF + XDR_QUADLEN(fh_size); 74 u32 *p = fid->raw; 75 int ret; 76 77 /* NULL translates to ESTALE */ 78 if (fh_len < len || fh_type != len) 79 return NULL; 80 81 fattr = nfs_alloc_fattr_with_label(NFS_SB(sb)); 82 if (fattr == NULL) { 83 dentry = ERR_PTR(-ENOMEM); 84 goto out; 85 } 86 87 fattr->fileid = ((u64)p[FILEID_HIGH_OFF] << 32) + p[FILEID_LOW_OFF]; 88 fattr->mode = p[FILE_I_TYPE_OFF]; 89 fattr->valid |= NFS_ATTR_FATTR_FILEID | NFS_ATTR_FATTR_TYPE; 90 91 dprintk("%s: fileid %llu mode %d\n", __func__, fattr->fileid, fattr->mode); 92 93 inode = nfs_ilookup(sb, fattr, server_fh); 94 if (inode) 95 goto out_found; 96 97 rpc_ops = NFS_SB(sb)->nfs_client->rpc_ops; 98 ret = rpc_ops->getattr(NFS_SB(sb), server_fh, fattr, NULL); 99 if (ret) { 100 dprintk("%s: getattr failed %d\n", __func__, ret); 101 trace_nfs_fh_to_dentry(sb, server_fh, fattr->fileid, ret); 102 dentry = ERR_PTR(ret); 103 goto out_free_fattr; 104 } 105 106 inode = nfs_fhget(sb, server_fh, fattr); 107 108 out_found: 109 dentry = d_obtain_alias(inode); 110 out_free_fattr: 111 nfs_free_fattr(fattr); 112 out: 113 return dentry; 114 } 115 116 static struct dentry * 117 nfs_get_parent(struct dentry *dentry) 118 { 119 int ret; 120 struct inode *inode = d_inode(dentry), *pinode; 121 struct super_block *sb = inode->i_sb; 122 struct nfs_server *server = NFS_SB(sb); 123 struct nfs_fattr *fattr = NULL; 124 struct dentry *parent; 125 struct nfs_rpc_ops const *ops = server->nfs_client->rpc_ops; 126 struct nfs_fh fh; 127 128 if (!ops->lookupp) 129 return ERR_PTR(-EACCES); 130 131 fattr = nfs_alloc_fattr_with_label(server); 132 if (fattr == NULL) 133 return ERR_PTR(-ENOMEM); 134 135 ret = ops->lookupp(inode, &fh, fattr); 136 if (ret) { 137 parent = ERR_PTR(ret); 138 goto out; 139 } 140 141 pinode = nfs_fhget(sb, &fh, fattr); 142 parent = d_obtain_alias(pinode); 143 out: 144 nfs_free_fattr(fattr); 145 return parent; 146 } 147 148 const struct export_operations nfs_export_ops = { 149 .encode_fh = nfs_encode_fh, 150 .fh_to_dentry = nfs_fh_to_dentry, 151 .get_parent = nfs_get_parent, 152 .flags = EXPORT_OP_NOWCC|EXPORT_OP_NOSUBTREECHK| 153 EXPORT_OP_CLOSE_BEFORE_UNLINK|EXPORT_OP_REMOTE_FS| 154 EXPORT_OP_NOATOMIC_ATTR, 155 }; 156