1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (c) 2004-2005 Silicon Graphics, Inc. 4 * All Rights Reserved. 5 */ 6 #include "xfs.h" 7 #include "xfs_shared.h" 8 #include "xfs_format.h" 9 #include "xfs_log_format.h" 10 #include "xfs_trans_resv.h" 11 #include "xfs_mount.h" 12 #include "xfs_dir2.h" 13 #include "xfs_export.h" 14 #include "xfs_inode.h" 15 #include "xfs_trans.h" 16 #include "xfs_inode_item.h" 17 #include "xfs_icache.h" 18 #include "xfs_pnfs.h" 19 20 /* 21 * Note that we only accept fileids which are long enough rather than allow 22 * the parent generation number to default to zero. XFS considers zero a 23 * valid generation number not an invalid/wildcard value. 24 */ 25 static int xfs_fileid_length(int fileid_type) 26 { 27 switch (fileid_type) { 28 case FILEID_INO32_GEN: 29 return 2; 30 case FILEID_INO32_GEN_PARENT: 31 return 4; 32 case FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG: 33 return 3; 34 case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG: 35 return 6; 36 } 37 return FILEID_INVALID; 38 } 39 40 STATIC int 41 xfs_fs_encode_fh( 42 struct inode *inode, 43 __u32 *fh, 44 int *max_len, 45 struct inode *parent) 46 { 47 struct xfs_mount *mp = XFS_M(inode->i_sb); 48 struct fid *fid = (struct fid *)fh; 49 struct xfs_fid64 *fid64 = (struct xfs_fid64 *)fh; 50 int fileid_type; 51 int len; 52 53 /* Directories don't need their parent encoded, they have ".." */ 54 if (!parent) 55 fileid_type = FILEID_INO32_GEN; 56 else 57 fileid_type = FILEID_INO32_GEN_PARENT; 58 59 /* 60 * If the filesystem may contain 64bit inode numbers, we need 61 * to use larger file handles that can represent them. 62 * 63 * While we only allocate inodes that do not fit into 32 bits any 64 * large enough filesystem may contain them, thus the slightly 65 * confusing looking conditional below. 66 */ 67 if (!xfs_has_small_inums(mp) || xfs_is_inode32(mp)) 68 fileid_type |= XFS_FILEID_TYPE_64FLAG; 69 70 /* 71 * Only encode if there is enough space given. In practice 72 * this means we can't export a filesystem with 64bit inodes 73 * over NFSv2 with the subtree_check export option; the other 74 * seven combinations work. The real answer is "don't use v2". 75 */ 76 len = xfs_fileid_length(fileid_type); 77 if (*max_len < len) { 78 *max_len = len; 79 return FILEID_INVALID; 80 } 81 *max_len = len; 82 83 switch (fileid_type) { 84 case FILEID_INO32_GEN_PARENT: 85 fid->i32.parent_ino = XFS_I(parent)->i_ino; 86 fid->i32.parent_gen = parent->i_generation; 87 fallthrough; 88 case FILEID_INO32_GEN: 89 fid->i32.ino = XFS_I(inode)->i_ino; 90 fid->i32.gen = inode->i_generation; 91 break; 92 case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG: 93 fid64->parent_ino = XFS_I(parent)->i_ino; 94 fid64->parent_gen = parent->i_generation; 95 fallthrough; 96 case FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG: 97 fid64->ino = XFS_I(inode)->i_ino; 98 fid64->gen = inode->i_generation; 99 break; 100 } 101 102 return fileid_type; 103 } 104 105 STATIC struct inode * 106 xfs_nfs_get_inode( 107 struct super_block *sb, 108 u64 ino, 109 u32 generation) 110 { 111 xfs_mount_t *mp = XFS_M(sb); 112 xfs_inode_t *ip; 113 int error; 114 115 /* 116 * NFS can sometimes send requests for ino 0. Fail them gracefully. 117 */ 118 if (ino == 0) 119 return ERR_PTR(-ESTALE); 120 121 /* 122 * The XFS_IGET_UNTRUSTED means that an invalid inode number is just 123 * fine and not an indication of a corrupted filesystem as clients can 124 * send invalid file handles and we have to handle it gracefully.. 125 */ 126 error = xfs_iget(mp, NULL, ino, XFS_IGET_UNTRUSTED, 0, &ip); 127 if (error) { 128 129 /* 130 * EINVAL means the inode cluster doesn't exist anymore. 131 * EFSCORRUPTED means the metadata pointing to the inode cluster 132 * or the inode cluster itself is corrupt. This implies the 133 * filehandle is stale, so we should translate it here. 134 * We don't use ESTALE directly down the chain to not 135 * confuse applications using bulkstat that expect EINVAL. 136 */ 137 switch (error) { 138 case -EINVAL: 139 case -ENOENT: 140 case -EFSCORRUPTED: 141 error = -ESTALE; 142 break; 143 default: 144 break; 145 } 146 return ERR_PTR(error); 147 } 148 149 if (VFS_I(ip)->i_generation != generation) { 150 xfs_irele(ip); 151 return ERR_PTR(-ESTALE); 152 } 153 154 return VFS_I(ip); 155 } 156 157 STATIC struct dentry * 158 xfs_fs_fh_to_dentry(struct super_block *sb, struct fid *fid, 159 int fh_len, int fileid_type) 160 { 161 struct xfs_fid64 *fid64 = (struct xfs_fid64 *)fid; 162 struct inode *inode = NULL; 163 164 if (fh_len < xfs_fileid_length(fileid_type)) 165 return NULL; 166 167 switch (fileid_type) { 168 case FILEID_INO32_GEN_PARENT: 169 case FILEID_INO32_GEN: 170 inode = xfs_nfs_get_inode(sb, fid->i32.ino, fid->i32.gen); 171 break; 172 case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG: 173 case FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG: 174 inode = xfs_nfs_get_inode(sb, fid64->ino, fid64->gen); 175 break; 176 } 177 178 return d_obtain_alias(inode); 179 } 180 181 STATIC struct dentry * 182 xfs_fs_fh_to_parent(struct super_block *sb, struct fid *fid, 183 int fh_len, int fileid_type) 184 { 185 struct xfs_fid64 *fid64 = (struct xfs_fid64 *)fid; 186 struct inode *inode = NULL; 187 188 if (fh_len < xfs_fileid_length(fileid_type)) 189 return NULL; 190 191 switch (fileid_type) { 192 case FILEID_INO32_GEN_PARENT: 193 inode = xfs_nfs_get_inode(sb, fid->i32.parent_ino, 194 fid->i32.parent_gen); 195 break; 196 case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG: 197 inode = xfs_nfs_get_inode(sb, fid64->parent_ino, 198 fid64->parent_gen); 199 break; 200 } 201 202 return d_obtain_alias(inode); 203 } 204 205 STATIC struct dentry * 206 xfs_fs_get_parent( 207 struct dentry *child) 208 { 209 int error; 210 struct xfs_inode *cip; 211 212 error = xfs_lookup(XFS_I(d_inode(child)), &xfs_name_dotdot, &cip, NULL); 213 if (unlikely(error)) 214 return ERR_PTR(error); 215 216 return d_obtain_alias(VFS_I(cip)); 217 } 218 219 STATIC int 220 xfs_fs_nfs_commit_metadata( 221 struct inode *inode) 222 { 223 return xfs_log_force_inode(XFS_I(inode)); 224 } 225 226 const struct export_operations xfs_export_operations = { 227 .encode_fh = xfs_fs_encode_fh, 228 .fh_to_dentry = xfs_fs_fh_to_dentry, 229 .fh_to_parent = xfs_fs_fh_to_parent, 230 .get_parent = xfs_fs_get_parent, 231 .commit_metadata = xfs_fs_nfs_commit_metadata, 232 #ifdef CONFIG_EXPORTFS_BLOCK_OPS 233 .get_uuid = xfs_fs_get_uuid, 234 .map_blocks = xfs_fs_map_blocks, 235 .commit_blocks = xfs_fs_commit_blocks, 236 #endif 237 }; 238