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