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 static int ceph_encode_fh(struct dentry *dentry, u32 *rawfh, int *max_len, 44 int connectable) 45 { 46 int type; 47 struct ceph_nfs_fh *fh = (void *)rawfh; 48 struct ceph_nfs_confh *cfh = (void *)rawfh; 49 struct dentry *parent; 50 struct inode *inode = dentry->d_inode; 51 int connected_handle_length = sizeof(*cfh)/4; 52 int handle_length = sizeof(*fh)/4; 53 54 /* don't re-export snaps */ 55 if (ceph_snap(inode) != CEPH_NOSNAP) 56 return -EINVAL; 57 58 spin_lock(&dentry->d_lock); 59 parent = dget(dentry->d_parent); 60 spin_unlock(&dentry->d_lock); 61 62 if (*max_len >= connected_handle_length) { 63 dout("encode_fh %p connectable\n", dentry); 64 cfh->ino = ceph_ino(dentry->d_inode); 65 cfh->parent_ino = ceph_ino(parent->d_inode); 66 cfh->parent_name_hash = ceph_dentry_hash(parent->d_inode, 67 dentry); 68 *max_len = connected_handle_length; 69 type = 2; 70 } else if (*max_len >= handle_length) { 71 if (connectable) { 72 *max_len = connected_handle_length; 73 type = 255; 74 } else { 75 dout("encode_fh %p\n", dentry); 76 fh->ino = ceph_ino(dentry->d_inode); 77 *max_len = handle_length; 78 type = 1; 79 } 80 } else { 81 *max_len = handle_length; 82 type = 255; 83 } 84 dput(parent); 85 return type; 86 } 87 88 /* 89 * convert regular fh to dentry 90 * 91 * FIXME: we should try harder by querying the mds for the ino. 92 */ 93 static struct dentry *__fh_to_dentry(struct super_block *sb, 94 struct ceph_nfs_fh *fh) 95 { 96 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc; 97 struct inode *inode; 98 struct dentry *dentry; 99 struct ceph_vino vino; 100 int err; 101 102 dout("__fh_to_dentry %llx\n", fh->ino); 103 vino.ino = fh->ino; 104 vino.snap = CEPH_NOSNAP; 105 inode = ceph_find_inode(sb, vino); 106 if (!inode) { 107 struct ceph_mds_request *req; 108 109 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPINO, 110 USE_ANY_MDS); 111 if (IS_ERR(req)) 112 return ERR_CAST(req); 113 114 req->r_ino1 = vino; 115 req->r_num_caps = 1; 116 err = ceph_mdsc_do_request(mdsc, NULL, req); 117 inode = req->r_target_inode; 118 if (inode) 119 ihold(inode); 120 ceph_mdsc_put_request(req); 121 if (!inode) 122 return ERR_PTR(-ESTALE); 123 } 124 125 dentry = d_obtain_alias(inode); 126 if (IS_ERR(dentry)) { 127 pr_err("fh_to_dentry %llx -- inode %p but ENOMEM\n", 128 fh->ino, inode); 129 iput(inode); 130 return dentry; 131 } 132 err = ceph_init_dentry(dentry); 133 if (err < 0) { 134 iput(inode); 135 return ERR_PTR(err); 136 } 137 dout("__fh_to_dentry %llx %p dentry %p\n", fh->ino, inode, dentry); 138 return dentry; 139 } 140 141 /* 142 * convert connectable fh to dentry 143 */ 144 static struct dentry *__cfh_to_dentry(struct super_block *sb, 145 struct ceph_nfs_confh *cfh) 146 { 147 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc; 148 struct inode *inode; 149 struct dentry *dentry; 150 struct ceph_vino vino; 151 int err; 152 153 dout("__cfh_to_dentry %llx (%llx/%x)\n", 154 cfh->ino, cfh->parent_ino, cfh->parent_name_hash); 155 156 vino.ino = cfh->ino; 157 vino.snap = CEPH_NOSNAP; 158 inode = ceph_find_inode(sb, vino); 159 if (!inode) { 160 struct ceph_mds_request *req; 161 162 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPHASH, 163 USE_ANY_MDS); 164 if (IS_ERR(req)) 165 return ERR_CAST(req); 166 167 req->r_ino1 = vino; 168 req->r_ino2.ino = cfh->parent_ino; 169 req->r_ino2.snap = CEPH_NOSNAP; 170 req->r_path2 = kmalloc(16, GFP_NOFS); 171 snprintf(req->r_path2, 16, "%d", cfh->parent_name_hash); 172 req->r_num_caps = 1; 173 err = ceph_mdsc_do_request(mdsc, NULL, req); 174 inode = req->r_target_inode; 175 if (inode) 176 ihold(inode); 177 ceph_mdsc_put_request(req); 178 if (!inode) 179 return ERR_PTR(err ? err : -ESTALE); 180 } 181 182 dentry = d_obtain_alias(inode); 183 if (IS_ERR(dentry)) { 184 pr_err("cfh_to_dentry %llx -- inode %p but ENOMEM\n", 185 cfh->ino, inode); 186 iput(inode); 187 return dentry; 188 } 189 err = ceph_init_dentry(dentry); 190 if (err < 0) { 191 iput(inode); 192 return ERR_PTR(err); 193 } 194 dout("__cfh_to_dentry %llx %p dentry %p\n", cfh->ino, inode, dentry); 195 return dentry; 196 } 197 198 static struct dentry *ceph_fh_to_dentry(struct super_block *sb, struct fid *fid, 199 int fh_len, int fh_type) 200 { 201 if (fh_type == 1) 202 return __fh_to_dentry(sb, (struct ceph_nfs_fh *)fid->raw); 203 else 204 return __cfh_to_dentry(sb, (struct ceph_nfs_confh *)fid->raw); 205 } 206 207 /* 208 * get parent, if possible. 209 * 210 * FIXME: we could do better by querying the mds to discover the 211 * parent. 212 */ 213 static struct dentry *ceph_fh_to_parent(struct super_block *sb, 214 struct fid *fid, 215 int fh_len, int fh_type) 216 { 217 struct ceph_nfs_confh *cfh = (void *)fid->raw; 218 struct ceph_vino vino; 219 struct inode *inode; 220 struct dentry *dentry; 221 int err; 222 223 if (fh_type == 1) 224 return ERR_PTR(-ESTALE); 225 226 pr_debug("fh_to_parent %llx/%d\n", cfh->parent_ino, 227 cfh->parent_name_hash); 228 229 vino.ino = cfh->ino; 230 vino.snap = CEPH_NOSNAP; 231 inode = ceph_find_inode(sb, vino); 232 if (!inode) 233 return ERR_PTR(-ESTALE); 234 235 dentry = d_obtain_alias(inode); 236 if (IS_ERR(dentry)) { 237 pr_err("fh_to_parent %llx -- inode %p but ENOMEM\n", 238 cfh->ino, inode); 239 iput(inode); 240 return dentry; 241 } 242 err = ceph_init_dentry(dentry); 243 if (err < 0) { 244 iput(inode); 245 return ERR_PTR(err); 246 } 247 dout("fh_to_parent %llx %p dentry %p\n", cfh->ino, inode, dentry); 248 return dentry; 249 } 250 251 const struct export_operations ceph_export_ops = { 252 .encode_fh = ceph_encode_fh, 253 .fh_to_dentry = ceph_fh_to_dentry, 254 .fh_to_parent = ceph_fh_to_parent, 255 }; 256