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_log.h" 19 #include "xfs_pnfs.h" 20 21 /* 22 * Note that we only accept fileids which are long enough rather than allow 23 * the parent generation number to default to zero. XFS considers zero a 24 * valid generation number not an invalid/wildcard value. 25 */ 26 static int xfs_fileid_length(int fileid_type) 27 { 28 switch (fileid_type) { 29 case FILEID_INO32_GEN: 30 return 2; 31 case FILEID_INO32_GEN_PARENT: 32 return 4; 33 case FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG: 34 return 3; 35 case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG: 36 return 6; 37 } 38 return FILEID_INVALID; 39 } 40 41 STATIC int 42 xfs_fs_encode_fh( 43 struct inode *inode, 44 __u32 *fh, 45 int *max_len, 46 struct inode *parent) 47 { 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 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_M(inode->i_sb)->m_flags & XFS_MOUNT_SMALL_INUMS) || 68 (XFS_M(inode->i_sb)->m_flags & XFS_MOUNT_32BITINODES)) 69 fileid_type |= XFS_FILEID_TYPE_64FLAG; 70 71 /* 72 * Only encode if there is enough space given. In practice 73 * this means we can't export a filesystem with 64bit inodes 74 * over NFSv2 with the subtree_check export option; the other 75 * seven combinations work. The real answer is "don't use v2". 76 */ 77 len = xfs_fileid_length(fileid_type); 78 if (*max_len < len) { 79 *max_len = len; 80 return FILEID_INVALID; 81 } 82 *max_len = len; 83 84 switch (fileid_type) { 85 case FILEID_INO32_GEN_PARENT: 86 fid->i32.parent_ino = XFS_I(parent)->i_ino; 87 fid->i32.parent_gen = parent->i_generation; 88 /*FALLTHRU*/ 89 case FILEID_INO32_GEN: 90 fid->i32.ino = XFS_I(inode)->i_ino; 91 fid->i32.gen = inode->i_generation; 92 break; 93 case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG: 94 fid64->parent_ino = XFS_I(parent)->i_ino; 95 fid64->parent_gen = parent->i_generation; 96 /*FALLTHRU*/ 97 case FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG: 98 fid64->ino = XFS_I(inode)->i_ino; 99 fid64->gen = inode->i_generation; 100 break; 101 } 102 103 return fileid_type; 104 } 105 106 STATIC struct inode * 107 xfs_nfs_get_inode( 108 struct super_block *sb, 109 u64 ino, 110 u32 generation) 111 { 112 xfs_mount_t *mp = XFS_M(sb); 113 xfs_inode_t *ip; 114 int error; 115 116 /* 117 * NFS can sometimes send requests for ino 0. Fail them gracefully. 118 */ 119 if (ino == 0) 120 return ERR_PTR(-ESTALE); 121 122 /* 123 * The XFS_IGET_UNTRUSTED means that an invalid inode number is just 124 * fine and not an indication of a corrupted filesystem as clients can 125 * send invalid file handles and we have to handle it gracefully.. 126 */ 127 error = xfs_iget(mp, NULL, ino, XFS_IGET_UNTRUSTED, 0, &ip); 128 if (error) { 129 130 /* 131 * EINVAL means the inode cluster doesn't exist anymore. 132 * EFSCORRUPTED means the metadata pointing to the inode cluster 133 * or the inode cluster itself is corrupt. This implies the 134 * filehandle is stale, so we should translate it here. 135 * We don't use ESTALE directly down the chain to not 136 * confuse applications using bulkstat that expect EINVAL. 137 */ 138 switch (error) { 139 case -EINVAL: 140 case -ENOENT: 141 case -EFSCORRUPTED: 142 error = -ESTALE; 143 break; 144 default: 145 break; 146 } 147 return ERR_PTR(error); 148 } 149 150 if (VFS_I(ip)->i_generation != generation) { 151 xfs_irele(ip); 152 return ERR_PTR(-ESTALE); 153 } 154 155 return VFS_I(ip); 156 } 157 158 STATIC struct dentry * 159 xfs_fs_fh_to_dentry(struct super_block *sb, struct fid *fid, 160 int fh_len, int fileid_type) 161 { 162 struct xfs_fid64 *fid64 = (struct xfs_fid64 *)fid; 163 struct inode *inode = NULL; 164 165 if (fh_len < xfs_fileid_length(fileid_type)) 166 return NULL; 167 168 switch (fileid_type) { 169 case FILEID_INO32_GEN_PARENT: 170 case FILEID_INO32_GEN: 171 inode = xfs_nfs_get_inode(sb, fid->i32.ino, fid->i32.gen); 172 break; 173 case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG: 174 case FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG: 175 inode = xfs_nfs_get_inode(sb, fid64->ino, fid64->gen); 176 break; 177 } 178 179 return d_obtain_alias(inode); 180 } 181 182 STATIC struct dentry * 183 xfs_fs_fh_to_parent(struct super_block *sb, struct fid *fid, 184 int fh_len, int fileid_type) 185 { 186 struct xfs_fid64 *fid64 = (struct xfs_fid64 *)fid; 187 struct inode *inode = NULL; 188 189 if (fh_len < xfs_fileid_length(fileid_type)) 190 return NULL; 191 192 switch (fileid_type) { 193 case FILEID_INO32_GEN_PARENT: 194 inode = xfs_nfs_get_inode(sb, fid->i32.parent_ino, 195 fid->i32.parent_gen); 196 break; 197 case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG: 198 inode = xfs_nfs_get_inode(sb, fid64->parent_ino, 199 fid64->parent_gen); 200 break; 201 } 202 203 return d_obtain_alias(inode); 204 } 205 206 STATIC struct dentry * 207 xfs_fs_get_parent( 208 struct dentry *child) 209 { 210 int error; 211 struct xfs_inode *cip; 212 213 error = xfs_lookup(XFS_I(d_inode(child)), &xfs_name_dotdot, &cip, NULL); 214 if (unlikely(error)) 215 return ERR_PTR(error); 216 217 return d_obtain_alias(VFS_I(cip)); 218 } 219 220 STATIC int 221 xfs_fs_nfs_commit_metadata( 222 struct inode *inode) 223 { 224 struct xfs_inode *ip = XFS_I(inode); 225 struct xfs_mount *mp = ip->i_mount; 226 xfs_lsn_t lsn = 0; 227 228 xfs_ilock(ip, XFS_ILOCK_SHARED); 229 if (xfs_ipincount(ip)) 230 lsn = ip->i_itemp->ili_last_lsn; 231 xfs_iunlock(ip, XFS_ILOCK_SHARED); 232 233 if (!lsn) 234 return 0; 235 return xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, NULL); 236 } 237 238 const struct export_operations xfs_export_operations = { 239 .encode_fh = xfs_fs_encode_fh, 240 .fh_to_dentry = xfs_fs_fh_to_dentry, 241 .fh_to_parent = xfs_fs_fh_to_parent, 242 .get_parent = xfs_fs_get_parent, 243 .commit_metadata = xfs_fs_nfs_commit_metadata, 244 #ifdef CONFIG_EXPORTFS_BLOCK_OPS 245 .get_uuid = xfs_fs_get_uuid, 246 .map_blocks = xfs_fs_map_blocks, 247 .commit_blocks = xfs_fs_commit_blocks, 248 #endif 249 }; 250