1 #include <linux/ceph/ceph_debug.h> 2 3 #include <linux/file.h> 4 #include <linux/namei.h> 5 #include <linux/random.h> 6 7 #include "super.h" 8 #include "mds_client.h" 9 #include <linux/ceph/pagelist.h> 10 11 static u64 lock_secret; 12 13 static inline u64 secure_addr(void *addr) 14 { 15 u64 v = lock_secret ^ (u64)(unsigned long)addr; 16 /* 17 * Set the most significant bit, so that MDS knows the 'owner' 18 * is sufficient to identify the owner of lock. (old code uses 19 * both 'owner' and 'pid') 20 */ 21 v |= (1ULL << 63); 22 return v; 23 } 24 25 void __init ceph_flock_init(void) 26 { 27 get_random_bytes(&lock_secret, sizeof(lock_secret)); 28 } 29 30 /** 31 * Implement fcntl and flock locking functions. 32 */ 33 static int ceph_lock_message(u8 lock_type, u16 operation, struct file *file, 34 int cmd, u8 wait, struct file_lock *fl) 35 { 36 struct inode *inode = file_inode(file); 37 struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc; 38 struct ceph_mds_request *req; 39 int err; 40 u64 length = 0; 41 u64 owner; 42 43 req = ceph_mdsc_create_request(mdsc, operation, USE_AUTH_MDS); 44 if (IS_ERR(req)) 45 return PTR_ERR(req); 46 req->r_inode = inode; 47 ihold(inode); 48 req->r_num_caps = 1; 49 50 /* mds requires start and length rather than start and end */ 51 if (LLONG_MAX == fl->fl_end) 52 length = 0; 53 else 54 length = fl->fl_end - fl->fl_start + 1; 55 56 if (lock_type == CEPH_LOCK_FCNTL) 57 owner = secure_addr(fl->fl_owner); 58 else 59 owner = secure_addr(fl->fl_file); 60 61 dout("ceph_lock_message: rule: %d, op: %d, owner: %llx, pid: %llu, " 62 "start: %llu, length: %llu, wait: %d, type: %d", (int)lock_type, 63 (int)operation, owner, (u64)fl->fl_pid, fl->fl_start, length, 64 wait, fl->fl_type); 65 66 req->r_args.filelock_change.rule = lock_type; 67 req->r_args.filelock_change.type = cmd; 68 req->r_args.filelock_change.owner = cpu_to_le64(owner); 69 req->r_args.filelock_change.pid = cpu_to_le64((u64)fl->fl_pid); 70 req->r_args.filelock_change.start = cpu_to_le64(fl->fl_start); 71 req->r_args.filelock_change.length = cpu_to_le64(length); 72 req->r_args.filelock_change.wait = wait; 73 74 err = ceph_mdsc_do_request(mdsc, inode, req); 75 76 if (operation == CEPH_MDS_OP_GETFILELOCK) { 77 fl->fl_pid = le64_to_cpu(req->r_reply_info.filelock_reply->pid); 78 if (CEPH_LOCK_SHARED == req->r_reply_info.filelock_reply->type) 79 fl->fl_type = F_RDLCK; 80 else if (CEPH_LOCK_EXCL == req->r_reply_info.filelock_reply->type) 81 fl->fl_type = F_WRLCK; 82 else 83 fl->fl_type = F_UNLCK; 84 85 fl->fl_start = le64_to_cpu(req->r_reply_info.filelock_reply->start); 86 length = le64_to_cpu(req->r_reply_info.filelock_reply->start) + 87 le64_to_cpu(req->r_reply_info.filelock_reply->length); 88 if (length >= 1) 89 fl->fl_end = length -1; 90 else 91 fl->fl_end = 0; 92 93 } 94 ceph_mdsc_put_request(req); 95 dout("ceph_lock_message: rule: %d, op: %d, pid: %llu, start: %llu, " 96 "length: %llu, wait: %d, type: %d, err code %d", (int)lock_type, 97 (int)operation, (u64)fl->fl_pid, fl->fl_start, 98 length, wait, fl->fl_type, err); 99 return err; 100 } 101 102 /** 103 * Attempt to set an fcntl lock. 104 * For now, this just goes away to the server. Later it may be more awesome. 105 */ 106 int ceph_lock(struct file *file, int cmd, struct file_lock *fl) 107 { 108 u8 lock_cmd; 109 int err; 110 u8 wait = 0; 111 u16 op = CEPH_MDS_OP_SETFILELOCK; 112 113 if (!(fl->fl_flags & FL_POSIX)) 114 return -ENOLCK; 115 /* No mandatory locks */ 116 if (__mandatory_lock(file->f_mapping->host) && fl->fl_type != F_UNLCK) 117 return -ENOLCK; 118 119 dout("ceph_lock, fl_owner: %p", fl->fl_owner); 120 121 /* set wait bit as appropriate, then make command as Ceph expects it*/ 122 if (IS_GETLK(cmd)) 123 op = CEPH_MDS_OP_GETFILELOCK; 124 else if (IS_SETLKW(cmd)) 125 wait = 1; 126 127 if (F_RDLCK == fl->fl_type) 128 lock_cmd = CEPH_LOCK_SHARED; 129 else if (F_WRLCK == fl->fl_type) 130 lock_cmd = CEPH_LOCK_EXCL; 131 else 132 lock_cmd = CEPH_LOCK_UNLOCK; 133 134 err = ceph_lock_message(CEPH_LOCK_FCNTL, op, file, lock_cmd, wait, fl); 135 if (!err) { 136 if (op != CEPH_MDS_OP_GETFILELOCK) { 137 dout("mds locked, locking locally"); 138 err = posix_lock_file(file, fl, NULL); 139 if (err && (CEPH_MDS_OP_SETFILELOCK == op)) { 140 /* undo! This should only happen if 141 * the kernel detects local 142 * deadlock. */ 143 ceph_lock_message(CEPH_LOCK_FCNTL, op, file, 144 CEPH_LOCK_UNLOCK, 0, fl); 145 dout("got %d on posix_lock_file, undid lock", 146 err); 147 } 148 } 149 150 } else if (err == -ERESTARTSYS) { 151 dout("undoing lock\n"); 152 ceph_lock_message(CEPH_LOCK_FCNTL, op, file, 153 CEPH_LOCK_UNLOCK, 0, fl); 154 } 155 return err; 156 } 157 158 int ceph_flock(struct file *file, int cmd, struct file_lock *fl) 159 { 160 u8 lock_cmd; 161 int err; 162 u8 wait = 0; 163 164 if (!(fl->fl_flags & FL_FLOCK)) 165 return -ENOLCK; 166 /* No mandatory locks */ 167 if (__mandatory_lock(file->f_mapping->host) && fl->fl_type != F_UNLCK) 168 return -ENOLCK; 169 170 dout("ceph_flock, fl_file: %p", fl->fl_file); 171 172 if (IS_SETLKW(cmd)) 173 wait = 1; 174 175 if (F_RDLCK == fl->fl_type) 176 lock_cmd = CEPH_LOCK_SHARED; 177 else if (F_WRLCK == fl->fl_type) 178 lock_cmd = CEPH_LOCK_EXCL; 179 else 180 lock_cmd = CEPH_LOCK_UNLOCK; 181 182 err = ceph_lock_message(CEPH_LOCK_FLOCK, CEPH_MDS_OP_SETFILELOCK, 183 file, lock_cmd, wait, fl); 184 if (!err) { 185 err = flock_lock_file_wait(file, fl); 186 if (err) { 187 ceph_lock_message(CEPH_LOCK_FLOCK, 188 CEPH_MDS_OP_SETFILELOCK, 189 file, CEPH_LOCK_UNLOCK, 0, fl); 190 dout("got %d on flock_lock_file_wait, undid lock", err); 191 } 192 } else if (err == -ERESTARTSYS) { 193 dout("undoing lock\n"); 194 ceph_lock_message(CEPH_LOCK_FLOCK, 195 CEPH_MDS_OP_SETFILELOCK, 196 file, CEPH_LOCK_UNLOCK, 0, fl); 197 } 198 return err; 199 } 200 201 /** 202 * Must be called with lock_flocks() already held. Fills in the passed 203 * counter variables, so you can prepare pagelist metadata before calling 204 * ceph_encode_locks. 205 */ 206 void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count) 207 { 208 struct file_lock *lock; 209 210 *fcntl_count = 0; 211 *flock_count = 0; 212 213 for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) { 214 if (lock->fl_flags & FL_POSIX) 215 ++(*fcntl_count); 216 else if (lock->fl_flags & FL_FLOCK) 217 ++(*flock_count); 218 } 219 dout("counted %d flock locks and %d fcntl locks", 220 *flock_count, *fcntl_count); 221 } 222 223 /** 224 * Encode the flock and fcntl locks for the given inode into the ceph_filelock 225 * array. Must be called with inode->i_lock already held. 226 * If we encounter more of a specific lock type than expected, return -ENOSPC. 227 */ 228 int ceph_encode_locks_to_buffer(struct inode *inode, 229 struct ceph_filelock *flocks, 230 int num_fcntl_locks, int num_flock_locks) 231 { 232 struct file_lock *lock; 233 int err = 0; 234 int seen_fcntl = 0; 235 int seen_flock = 0; 236 int l = 0; 237 238 dout("encoding %d flock and %d fcntl locks", num_flock_locks, 239 num_fcntl_locks); 240 241 for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) { 242 if (lock->fl_flags & FL_POSIX) { 243 ++seen_fcntl; 244 if (seen_fcntl > num_fcntl_locks) { 245 err = -ENOSPC; 246 goto fail; 247 } 248 err = lock_to_ceph_filelock(lock, &flocks[l]); 249 if (err) 250 goto fail; 251 ++l; 252 } 253 } 254 for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) { 255 if (lock->fl_flags & FL_FLOCK) { 256 ++seen_flock; 257 if (seen_flock > num_flock_locks) { 258 err = -ENOSPC; 259 goto fail; 260 } 261 err = lock_to_ceph_filelock(lock, &flocks[l]); 262 if (err) 263 goto fail; 264 ++l; 265 } 266 } 267 fail: 268 return err; 269 } 270 271 /** 272 * Copy the encoded flock and fcntl locks into the pagelist. 273 * Format is: #fcntl locks, sequential fcntl locks, #flock locks, 274 * sequential flock locks. 275 * Returns zero on success. 276 */ 277 int ceph_locks_to_pagelist(struct ceph_filelock *flocks, 278 struct ceph_pagelist *pagelist, 279 int num_fcntl_locks, int num_flock_locks) 280 { 281 int err = 0; 282 __le32 nlocks; 283 284 nlocks = cpu_to_le32(num_fcntl_locks); 285 err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks)); 286 if (err) 287 goto out_fail; 288 289 err = ceph_pagelist_append(pagelist, flocks, 290 num_fcntl_locks * sizeof(*flocks)); 291 if (err) 292 goto out_fail; 293 294 nlocks = cpu_to_le32(num_flock_locks); 295 err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks)); 296 if (err) 297 goto out_fail; 298 299 err = ceph_pagelist_append(pagelist, 300 &flocks[num_fcntl_locks], 301 num_flock_locks * sizeof(*flocks)); 302 out_fail: 303 return err; 304 } 305 306 /* 307 * Given a pointer to a lock, convert it to a ceph filelock 308 */ 309 int lock_to_ceph_filelock(struct file_lock *lock, 310 struct ceph_filelock *cephlock) 311 { 312 int err = 0; 313 cephlock->start = cpu_to_le64(lock->fl_start); 314 cephlock->length = cpu_to_le64(lock->fl_end - lock->fl_start + 1); 315 cephlock->client = cpu_to_le64(0); 316 cephlock->pid = cpu_to_le64((u64)lock->fl_pid); 317 if (lock->fl_flags & FL_POSIX) 318 cephlock->owner = cpu_to_le64(secure_addr(lock->fl_owner)); 319 else 320 cephlock->owner = cpu_to_le64(secure_addr(lock->fl_file)); 321 322 switch (lock->fl_type) { 323 case F_RDLCK: 324 cephlock->type = CEPH_LOCK_SHARED; 325 break; 326 case F_WRLCK: 327 cephlock->type = CEPH_LOCK_EXCL; 328 break; 329 case F_UNLCK: 330 cephlock->type = CEPH_LOCK_UNLOCK; 331 break; 332 default: 333 dout("Have unknown lock type %d", lock->fl_type); 334 err = -EINVAL; 335 } 336 337 return err; 338 } 339