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 = dentry->d_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 if (*max_len >= connected_handle_length) { 59 dout("encode_fh %p connectable\n", dentry); 60 cfh->ino = ceph_ino(dentry->d_inode); 61 cfh->parent_ino = ceph_ino(parent->d_inode); 62 cfh->parent_name_hash = ceph_dentry_hash(parent); 63 *max_len = connected_handle_length; 64 type = 2; 65 } else if (*max_len >= handle_length) { 66 if (connectable) { 67 *max_len = connected_handle_length; 68 return 255; 69 } 70 dout("encode_fh %p\n", dentry); 71 fh->ino = ceph_ino(dentry->d_inode); 72 *max_len = handle_length; 73 type = 1; 74 } else { 75 *max_len = handle_length; 76 return 255; 77 } 78 return type; 79 } 80 81 /* 82 * convert regular fh to dentry 83 * 84 * FIXME: we should try harder by querying the mds for the ino. 85 */ 86 static struct dentry *__fh_to_dentry(struct super_block *sb, 87 struct ceph_nfs_fh *fh) 88 { 89 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc; 90 struct inode *inode; 91 struct dentry *dentry; 92 struct ceph_vino vino; 93 int err; 94 95 dout("__fh_to_dentry %llx\n", fh->ino); 96 vino.ino = fh->ino; 97 vino.snap = CEPH_NOSNAP; 98 inode = ceph_find_inode(sb, vino); 99 if (!inode) { 100 struct ceph_mds_request *req; 101 102 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPINO, 103 USE_ANY_MDS); 104 if (IS_ERR(req)) 105 return ERR_CAST(req); 106 107 req->r_ino1 = vino; 108 req->r_num_caps = 1; 109 err = ceph_mdsc_do_request(mdsc, NULL, req); 110 inode = req->r_target_inode; 111 if (inode) 112 igrab(inode); 113 ceph_mdsc_put_request(req); 114 if (!inode) 115 return ERR_PTR(-ESTALE); 116 } 117 118 dentry = d_obtain_alias(inode); 119 if (IS_ERR(dentry)) { 120 pr_err("fh_to_dentry %llx -- inode %p but ENOMEM\n", 121 fh->ino, inode); 122 iput(inode); 123 return dentry; 124 } 125 err = ceph_init_dentry(dentry); 126 127 if (err < 0) { 128 iput(inode); 129 return ERR_PTR(err); 130 } 131 dout("__fh_to_dentry %llx %p dentry %p\n", fh->ino, inode, dentry); 132 return dentry; 133 } 134 135 /* 136 * convert connectable fh to dentry 137 */ 138 static struct dentry *__cfh_to_dentry(struct super_block *sb, 139 struct ceph_nfs_confh *cfh) 140 { 141 struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc; 142 struct inode *inode; 143 struct dentry *dentry; 144 struct ceph_vino vino; 145 int err; 146 147 dout("__cfh_to_dentry %llx (%llx/%x)\n", 148 cfh->ino, cfh->parent_ino, cfh->parent_name_hash); 149 150 vino.ino = cfh->ino; 151 vino.snap = CEPH_NOSNAP; 152 inode = ceph_find_inode(sb, vino); 153 if (!inode) { 154 struct ceph_mds_request *req; 155 156 req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPHASH, 157 USE_ANY_MDS); 158 if (IS_ERR(req)) 159 return ERR_CAST(req); 160 161 req->r_ino1 = vino; 162 req->r_ino2.ino = cfh->parent_ino; 163 req->r_ino2.snap = CEPH_NOSNAP; 164 req->r_path2 = kmalloc(16, GFP_NOFS); 165 snprintf(req->r_path2, 16, "%d", cfh->parent_name_hash); 166 req->r_num_caps = 1; 167 err = ceph_mdsc_do_request(mdsc, NULL, req); 168 inode = req->r_target_inode; 169 if (inode) 170 igrab(inode); 171 ceph_mdsc_put_request(req); 172 if (!inode) 173 return ERR_PTR(err ? err : -ESTALE); 174 } 175 176 dentry = d_obtain_alias(inode); 177 if (IS_ERR(dentry)) { 178 pr_err("cfh_to_dentry %llx -- inode %p but ENOMEM\n", 179 cfh->ino, inode); 180 iput(inode); 181 return dentry; 182 } 183 err = ceph_init_dentry(dentry); 184 if (err < 0) { 185 iput(inode); 186 return ERR_PTR(err); 187 } 188 dout("__cfh_to_dentry %llx %p dentry %p\n", cfh->ino, inode, dentry); 189 return dentry; 190 } 191 192 static struct dentry *ceph_fh_to_dentry(struct super_block *sb, struct fid *fid, 193 int fh_len, int fh_type) 194 { 195 if (fh_type == 1) 196 return __fh_to_dentry(sb, (struct ceph_nfs_fh *)fid->raw); 197 else 198 return __cfh_to_dentry(sb, (struct ceph_nfs_confh *)fid->raw); 199 } 200 201 /* 202 * get parent, if possible. 203 * 204 * FIXME: we could do better by querying the mds to discover the 205 * parent. 206 */ 207 static struct dentry *ceph_fh_to_parent(struct super_block *sb, 208 struct fid *fid, 209 int fh_len, int fh_type) 210 { 211 struct ceph_nfs_confh *cfh = (void *)fid->raw; 212 struct ceph_vino vino; 213 struct inode *inode; 214 struct dentry *dentry; 215 int err; 216 217 if (fh_type == 1) 218 return ERR_PTR(-ESTALE); 219 220 pr_debug("fh_to_parent %llx/%d\n", cfh->parent_ino, 221 cfh->parent_name_hash); 222 223 vino.ino = cfh->ino; 224 vino.snap = CEPH_NOSNAP; 225 inode = ceph_find_inode(sb, vino); 226 if (!inode) 227 return ERR_PTR(-ESTALE); 228 229 dentry = d_obtain_alias(inode); 230 if (IS_ERR(dentry)) { 231 pr_err("fh_to_parent %llx -- inode %p but ENOMEM\n", 232 cfh->ino, inode); 233 iput(inode); 234 return dentry; 235 } 236 err = ceph_init_dentry(dentry); 237 if (err < 0) { 238 iput(inode); 239 return ERR_PTR(err); 240 } 241 dout("fh_to_parent %llx %p dentry %p\n", cfh->ino, inode, dentry); 242 return dentry; 243 } 244 245 const struct export_operations ceph_export_ops = { 246 .encode_fh = ceph_encode_fh, 247 .fh_to_dentry = ceph_fh_to_dentry, 248 .fh_to_parent = ceph_fh_to_parent, 249 }; 250