1 #include <linux/ceph/ceph_debug.h> 2 3 #include <linux/exportfs.h> 4 #include <linux/slab.h> 5 #include <asm/unaligned.h> 6 7 #include "super.h" 8 #include "mds_client.h" 9 10 /* 11 * NFS export support 12 * 13 * NFS re-export of a ceph mount is, at present, only semireliable. 14 * The basic issue is that the Ceph architectures doesn't lend itself 15 * well to generating filehandles that will remain valid forever. 16 * 17 * So, we do our best. If you're lucky, your inode will be in the 18 * client's cache. If it's not, and you have a connectable fh, then 19 * the MDS server may be able to find it for you. Otherwise, you get 20 * ESTALE. 21 * 22 * There are ways to this more reliable, but in the non-connectable fh 23 * case, we won't every work perfectly, and in the connectable case, 24 * some changes are needed on the MDS side to work better. 25 */ 26 27 /* 28 * Basic fh 29 */ 30 struct ceph_nfs_fh { 31 u64 ino; 32 } __attribute__ ((packed)); 33 34 /* 35 * Larger 'connectable' fh that includes parent ino and name hash. 36 * Use this whenever possible, as it works more reliably. 37 */ 38 struct ceph_nfs_confh { 39 u64 ino, parent_ino; 40 u32 parent_name_hash; 41 } __attribute__ ((packed)); 42 43 /* 44 * The presence of @parent_inode here tells us whether NFS wants a 45 * connectable file handle. However, we want to make a connectionable 46 * file handle unconditionally so that the MDS gets as much of a hint 47 * as possible. That means we only use @parent_dentry to indicate 48 * whether nfsd wants a connectable fh, and whether we should indicate 49 * failure from a too-small @max_len. 50 */ 51 static int ceph_encode_fh(struct inode *inode, u32 *rawfh, int *max_len, 52 struct inode *parent_inode) 53 { 54 int type; 55 struct ceph_nfs_fh *fh = (void *)rawfh; 56 struct ceph_nfs_confh *cfh = (void *)rawfh; 57 int connected_handle_length = sizeof(*cfh)/4; 58 int handle_length = sizeof(*fh)/4; 59 struct dentry *dentry = d_find_alias(inode); 60 struct dentry *parent; 61 62 /* don't re-export snaps */ 63 if (ceph_snap(inode) != CEPH_NOSNAP) 64 return -EINVAL; 65 66 /* if we found an alias, generate a connectable fh */ 67 if (*max_len >= connected_handle_length && dentry) { 68 dout("encode_fh %p connectable\n", dentry); 69 spin_lock(&dentry->d_lock); 70 parent = dentry->d_parent; 71 cfh->ino = ceph_ino(inode); 72 cfh->parent_ino = ceph_ino(parent->d_inode); 73 cfh->parent_name_hash = ceph_dentry_hash(parent->d_inode, 74 dentry); 75 *max_len = connected_handle_length; 76 type = 2; 77 spin_unlock(&dentry->d_lock); 78 } else if (*max_len >= handle_length) { 79 if (parent_inode) { 80 /* nfsd wants connectable */ 81 *max_len = connected_handle_length; 82 type = 255; 83 } else { 84 dout("encode_fh %p\n", dentry); 85 fh->ino = ceph_ino(inode); 86 *max_len = handle_length; 87 type = 1; 88 } 89 } else { 90 *max_len = handle_length; 91 type = 255; 92 } 93 if (dentry) 94 dput(dentry); 95 return type; 96 } 97 98 /* 99 * convert regular fh to dentry 100 * 101 * FIXME: we should try harder by querying the mds for the ino. 102 */ 103 static struct dentry *__fh_to_dentry(struct super_block *sb, 104 struct ceph_nfs_fh *fh, int fh_len) 105 { 106 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc; 107 struct inode *inode; 108 struct dentry *dentry; 109 struct ceph_vino vino; 110 int err; 111 112 if (fh_len < sizeof(*fh) / 4) 113 return ERR_PTR(-ESTALE); 114 115 dout("__fh_to_dentry %llx\n", fh->ino); 116 vino.ino = fh->ino; 117 vino.snap = CEPH_NOSNAP; 118 inode = ceph_find_inode(sb, vino); 119 if (!inode) { 120 struct ceph_mds_request *req; 121 122 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPINO, 123 USE_ANY_MDS); 124 if (IS_ERR(req)) 125 return ERR_CAST(req); 126 127 req->r_ino1 = vino; 128 req->r_num_caps = 1; 129 err = ceph_mdsc_do_request(mdsc, NULL, req); 130 inode = req->r_target_inode; 131 if (inode) 132 ihold(inode); 133 ceph_mdsc_put_request(req); 134 if (!inode) 135 return ERR_PTR(-ESTALE); 136 } 137 138 dentry = d_obtain_alias(inode); 139 if (IS_ERR(dentry)) { 140 pr_err("fh_to_dentry %llx -- inode %p but ENOMEM\n", 141 fh->ino, inode); 142 iput(inode); 143 return dentry; 144 } 145 err = ceph_init_dentry(dentry); 146 if (err < 0) { 147 iput(inode); 148 return ERR_PTR(err); 149 } 150 dout("__fh_to_dentry %llx %p dentry %p\n", fh->ino, inode, dentry); 151 return dentry; 152 } 153 154 /* 155 * convert connectable fh to dentry 156 */ 157 static struct dentry *__cfh_to_dentry(struct super_block *sb, 158 struct ceph_nfs_confh *cfh, int fh_len) 159 { 160 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc; 161 struct inode *inode; 162 struct dentry *dentry; 163 struct ceph_vino vino; 164 int err; 165 166 if (fh_len < sizeof(*cfh) / 4) 167 return ERR_PTR(-ESTALE); 168 169 dout("__cfh_to_dentry %llx (%llx/%x)\n", 170 cfh->ino, cfh->parent_ino, cfh->parent_name_hash); 171 172 vino.ino = cfh->ino; 173 vino.snap = CEPH_NOSNAP; 174 inode = ceph_find_inode(sb, vino); 175 if (!inode) { 176 struct ceph_mds_request *req; 177 178 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPHASH, 179 USE_ANY_MDS); 180 if (IS_ERR(req)) 181 return ERR_CAST(req); 182 183 req->r_ino1 = vino; 184 req->r_ino2.ino = cfh->parent_ino; 185 req->r_ino2.snap = CEPH_NOSNAP; 186 req->r_path2 = kmalloc(16, GFP_NOFS); 187 snprintf(req->r_path2, 16, "%d", cfh->parent_name_hash); 188 req->r_num_caps = 1; 189 err = ceph_mdsc_do_request(mdsc, NULL, req); 190 inode = req->r_target_inode; 191 if (inode) 192 ihold(inode); 193 ceph_mdsc_put_request(req); 194 if (!inode) 195 return ERR_PTR(err ? err : -ESTALE); 196 } 197 198 dentry = d_obtain_alias(inode); 199 if (IS_ERR(dentry)) { 200 pr_err("cfh_to_dentry %llx -- inode %p but ENOMEM\n", 201 cfh->ino, inode); 202 iput(inode); 203 return dentry; 204 } 205 err = ceph_init_dentry(dentry); 206 if (err < 0) { 207 iput(inode); 208 return ERR_PTR(err); 209 } 210 dout("__cfh_to_dentry %llx %p dentry %p\n", cfh->ino, inode, dentry); 211 return dentry; 212 } 213 214 static struct dentry *ceph_fh_to_dentry(struct super_block *sb, struct fid *fid, 215 int fh_len, int fh_type) 216 { 217 if (fh_type == 1) 218 return __fh_to_dentry(sb, (struct ceph_nfs_fh *)fid->raw, 219 fh_len); 220 else 221 return __cfh_to_dentry(sb, (struct ceph_nfs_confh *)fid->raw, 222 fh_len); 223 } 224 225 /* 226 * get parent, if possible. 227 * 228 * FIXME: we could do better by querying the mds to discover the 229 * parent. 230 */ 231 static struct dentry *ceph_fh_to_parent(struct super_block *sb, 232 struct fid *fid, 233 int fh_len, int fh_type) 234 { 235 struct ceph_nfs_confh *cfh = (void *)fid->raw; 236 struct ceph_vino vino; 237 struct inode *inode; 238 struct dentry *dentry; 239 int err; 240 241 if (fh_type == 1) 242 return ERR_PTR(-ESTALE); 243 if (fh_len < sizeof(*cfh) / 4) 244 return ERR_PTR(-ESTALE); 245 246 pr_debug("fh_to_parent %llx/%d\n", cfh->parent_ino, 247 cfh->parent_name_hash); 248 249 vino.ino = cfh->ino; 250 vino.snap = CEPH_NOSNAP; 251 inode = ceph_find_inode(sb, vino); 252 if (!inode) 253 return ERR_PTR(-ESTALE); 254 255 dentry = d_obtain_alias(inode); 256 if (IS_ERR(dentry)) { 257 pr_err("fh_to_parent %llx -- inode %p but ENOMEM\n", 258 cfh->ino, inode); 259 iput(inode); 260 return dentry; 261 } 262 err = ceph_init_dentry(dentry); 263 if (err < 0) { 264 iput(inode); 265 return ERR_PTR(err); 266 } 267 dout("fh_to_parent %llx %p dentry %p\n", cfh->ino, inode, dentry); 268 return dentry; 269 } 270 271 const struct export_operations ceph_export_ops = { 272 .encode_fh = ceph_encode_fh, 273 .fh_to_dentry = ceph_fh_to_dentry, 274 .fh_to_parent = ceph_fh_to_parent, 275 }; 276