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