source4/ntvfs/posix/pvfs_lock.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    POSIX NTVFS backend - locking
   5
   6    Copyright (C) Andrew Tridgell 2004
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "vfs_posix.h"
  24 #include "system/time.h"
  25 #include "../lib/util/dlinklist.h"
  26 #include "messaging/messaging.h"
  27
  28
  29 /*
  30   check if we can perform IO on a range that might be locked
  31 */
  32 NTSTATUS pvfs_check_lock(struct pvfs_state *pvfs,
  33                          struct pvfs_file *f,
  34                          uint32_t smbpid,
  35                          uint64_t offset, uint64_t count,
  36                          enum brl_type rw)
  37 {
  38         if (!(pvfs->flags & PVFS_FLAG_STRICT_LOCKING)) {
  39                 return NT_STATUS_OK;
  40         }
  41
  42         return brlock_locktest(pvfs->brl_context,
  43                             f->brl_handle,
  44                             smbpid,
  45                             offset, count, rw);
  46 }
  47
  48 /* this state structure holds information about a lock we are waiting on */
  49 struct pvfs_pending_lock {
  50         struct pvfs_pending_lock *next, *prev;
  51         struct pvfs_state *pvfs;
  52         union smb_lock *lck;
  53         struct pvfs_file *f;
  54         struct ntvfs_request *req;
  55         int pending_lock;
  56         struct pvfs_wait *wait_handle;
  57         struct timeval end_time;
  58 };
  59
  60 /*
  61   a secondary attempt to setup a lock has failed - back out
  62   the locks we did get and send an error
  63 */
  64 static void pvfs_lock_async_failed(struct pvfs_state *pvfs,
  65                                    struct ntvfs_request *req,
  66                                    struct pvfs_file *f,
  67                                    struct smb_lock_entry *locks,
  68                                    int i,
  69                                    NTSTATUS status)
  70 {
  71         /* undo the locks we just did */
  72         for (i--;i>=0;i--) {
  73                 brlock_unlock(pvfs->brl_context,
  74                            f->brl_handle,
  75                            locks[i].pid,
  76                            locks[i].offset,
  77                            locks[i].count);
  78                 f->lock_count--;
  79         }
  80         req->async_states->status = status;
  81         req->async_states->send_fn(req);
  82 }
  83
  84
  85 /*
  86   called when we receive a pending lock notification. It means that
  87   either our lock timed out or someone else has unlocked a overlapping
  88   range, so we should try the lock again. Note that on timeout we
  89   do retry the lock, giving it a last chance.
  90 */
  91 static void pvfs_pending_lock_continue(void *private_data, enum pvfs_wait_notice reason)
  92 {
  93         struct pvfs_pending_lock *pending = talloc_get_type(private_data,
  94                                             struct pvfs_pending_lock);
  95         struct pvfs_state *pvfs = pending->pvfs;
  96         struct pvfs_file *f = pending->f;
  97         struct ntvfs_request *req = pending->req;
  98         union smb_lock *lck = pending->lck;
  99         struct smb_lock_entry *locks;
 100         enum brl_type rw;
 101         NTSTATUS status;
 102         int i;
 103         bool timed_out;
 104
 105         timed_out = (reason != PVFS_WAIT_EVENT);
 106
 107         locks = lck->lockx.in.locks + lck->lockx.in.ulock_cnt;
 108
 109         if (lck->lockx.in.mode & LOCKING_ANDX_SHARED_LOCK) {
 110                 rw = READ_LOCK;
 111         } else {
 112                 rw = WRITE_LOCK;
 113         }
 114
 115         DLIST_REMOVE(f->pending_list, pending);
 116
 117         /* we don't retry on a cancel */
 118         if (reason == PVFS_WAIT_CANCEL) {
 119                 if (pvfs->ntvfs->ctx->protocol < PROTOCOL_SMB2_02) {
 120                         status = NT_STATUS_FILE_LOCK_CONFLICT;
 121                 } else {
 122                         status = NT_STATUS_CANCELLED;
 123                 }
 124         } else {
 125                 /*
 126                  * here it's important to pass the pending pointer
 127                  * because with this we'll get the correct error code
 128                  * FILE_LOCK_CONFLICT in the error case
 129                  */
 130                 status = brlock_lock(pvfs->brl_context,
 131                                   f->brl_handle,
 132                                   locks[pending->pending_lock].pid,
 133                                   locks[pending->pending_lock].offset,
 134                                   locks[pending->pending_lock].count,
 135                                   rw, pending);
 136         }
 137         if (NT_STATUS_IS_OK(status)) {
 138                 f->lock_count++;
 139                 timed_out = false;
 140         }
 141
 142         /* if we have failed and timed out, or succeeded, then we
 143            don't need the pending lock any more */
 144         if (NT_STATUS_IS_OK(status) || timed_out) {
 145                 NTSTATUS status2;
 146                 status2 = brlock_remove_pending(pvfs->brl_context,
 147                                              f->brl_handle, pending);
 148                 if (!NT_STATUS_IS_OK(status2)) {
 149                         DEBUG(0,("pvfs_lock: failed to remove pending lock - %s\n", nt_errstr(status2)));
 150                 }
 151                 talloc_free(pending->wait_handle);
 152         }
 153
 154         if (!NT_STATUS_IS_OK(status)) {
 155                 if (timed_out) {
 156                         /* no more chances */
 157                         pvfs_lock_async_failed(pvfs, req, f, locks, pending->pending_lock, status);
 158                         talloc_free(pending);
 159                 } else {
 160                         /* we can try again */
 161                         DLIST_ADD(f->pending_list, pending);
 162                 }
 163                 return;
 164         }
 165
 166         /* if we haven't timed out yet, then we can do more pending locks */
 167         if (rw == READ_LOCK) {
 168                 rw = PENDING_READ_LOCK;
 169         } else {
 170                 rw = PENDING_WRITE_LOCK;
 171         }
 172
 173         /* we've now got the pending lock. try and get the rest, which might
 174            lead to more pending locks */
 175         for (i=pending->pending_lock+1;i<lck->lockx.in.lock_cnt;i++) {
 176                 pending->pending_lock = i;
 177
 178                 status = brlock_lock(pvfs->brl_context,
 179                                   f->brl_handle,
 180                                   locks[i].pid,
 181                                   locks[i].offset,
 182                                   locks[i].count,
 183                                   rw, pending);
 184                 if (!NT_STATUS_IS_OK(status)) {
 185                         /* a timed lock failed - setup a wait message to handle
 186                            the pending lock notification or a timeout */
 187                         pending->wait_handle = pvfs_wait_message(pvfs, req, MSG_BRL_RETRY,
 188                                                                  pending->end_time,
 189                                                                  pvfs_pending_lock_continue,
 190                                                                  pending);
 191                         if (pending->wait_handle == NULL) {
 192                                 pvfs_lock_async_failed(pvfs, req, f, locks, i, NT_STATUS_NO_MEMORY);
 193                                 talloc_free(pending);
 194                         } else {
 195                                 talloc_steal(pending, pending->wait_handle);
 196                                 DLIST_ADD(f->pending_list, pending);
 197                         }
 198                         return;
 199                 }
 200
 201                 f->lock_count++;
 202         }
 203
 204         /* we've managed to get all the locks. Tell the client */
 205         req->async_states->status = NT_STATUS_OK;
 206         req->async_states->send_fn(req);
 207         talloc_free(pending);
 208 }
 209
 210
 211 /*
 212   called when we close a file that might have locks
 213 */
 214 void pvfs_lock_close(struct pvfs_state *pvfs, struct pvfs_file *f)
 215 {
 216         struct pvfs_pending_lock *p, *next;
 217
 218         if (f->lock_count || f->pending_list) {
 219                 DEBUG(5,("pvfs_lock: removing %.0f locks on close\n",
 220                          (double)f->lock_count));
 221                 brlock_close(f->pvfs->brl_context, f->brl_handle);
 222                 f->lock_count = 0;
 223         }
 224
 225         /* reply to all the pending lock requests, telling them the
 226            lock failed */
 227         for (p=f->pending_list;p;p=next) {
 228                 next = p->next;
 229                 DLIST_REMOVE(f->pending_list, p);
 230                 p->req->async_states->status = NT_STATUS_RANGE_NOT_LOCKED;
 231                 p->req->async_states->send_fn(p->req);
 232         }
 233 }
 234
 235
 236 /*
 237   cancel a set of locks
 238 */
 239 static NTSTATUS pvfs_lock_cancel(struct pvfs_state *pvfs, struct ntvfs_request *req, union smb_lock *lck,
 240                                  struct pvfs_file *f)
 241 {
 242         struct pvfs_pending_lock *p;
 243
 244         for (p=f->pending_list;p;p=p->next) {
 245                 /* check if the lock request matches exactly - you can only cancel with exact matches */
 246                 if (p->lck->lockx.in.ulock_cnt == lck->lockx.in.ulock_cnt &&
 247                     p->lck->lockx.in.lock_cnt  == lck->lockx.in.lock_cnt &&
 248                     p->lck->lockx.in.file.ntvfs== lck->lockx.in.file.ntvfs &&
 249                     p->lck->lockx.in.mode      == (lck->lockx.in.mode & ~LOCKING_ANDX_CANCEL_LOCK)) {
 250                         int i;
 251
 252                         for (i=0;i<lck->lockx.in.ulock_cnt + lck->lockx.in.lock_cnt;i++) {
 253                                 if (p->lck->lockx.in.locks[i].pid != lck->lockx.in.locks[i].pid ||
 254                                     p->lck->lockx.in.locks[i].offset != lck->lockx.in.locks[i].offset ||
 255                                     p->lck->lockx.in.locks[i].count != lck->lockx.in.locks[i].count) {
 256                                         break;
 257                                 }
 258                         }
 259                         if (i < lck->lockx.in.ulock_cnt) continue;
 260
 261                         /* an exact match! we can cancel it, which is equivalent
 262                            to triggering the timeout early */
 263                         pvfs_pending_lock_continue(p, PVFS_WAIT_TIMEOUT);
 264                         return NT_STATUS_OK;
 265                 }
 266         }
 267
 268         return NT_STATUS_DOS(ERRDOS, ERRcancelviolation);
 269 }
 270
 271
 272 /*
 273   lock or unlock a byte range
 274 */
 275 NTSTATUS pvfs_lock(struct ntvfs_module_context *ntvfs,
 276                    struct ntvfs_request *req, union smb_lock *lck)
 277 {
 278         struct pvfs_state *pvfs = talloc_get_type(ntvfs->private_data,
 279                                   struct pvfs_state);
 280         struct pvfs_file *f;
 281         struct smb_lock_entry *locks;
 282         int i;
 283         enum brl_type rw;
 284         struct pvfs_pending_lock *pending = NULL;
 285         NTSTATUS status;
 286
 287         if (lck->generic.level != RAW_LOCK_GENERIC) {
 288                 return ntvfs_map_lock(ntvfs, req, lck);
 289         }
 290
 291         if (lck->lockx.in.mode & LOCKING_ANDX_OPLOCK_RELEASE) {
 292                 return pvfs_oplock_release(ntvfs, req, lck);
 293         }
 294
 295         f = pvfs_find_fd(pvfs, req, lck->lockx.in.file.ntvfs);
 296         if (!f) {
 297                 return NT_STATUS_INVALID_HANDLE;
 298         }
 299
 300         if (f->handle->fd == -1) {
 301                 return NT_STATUS_FILE_IS_A_DIRECTORY;
 302         }
 303
 304         status = pvfs_break_level2_oplocks(f);
 305         NT_STATUS_NOT_OK_RETURN(status);
 306
 307         if (lck->lockx.in.timeout != 0 &&
 308             (req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
 309                 pending = talloc(f, struct pvfs_pending_lock);
 310                 if (pending == NULL) {
 311                         return NT_STATUS_NO_MEMORY;
 312                 }
 313
 314                 pending->pvfs = pvfs;
 315                 pending->lck = lck;
 316                 pending->f = f;
 317                 pending->req = req;
 318
 319                 pending->end_time =
 320                         timeval_current_ofs_msec(lck->lockx.in.timeout);
 321         }
 322
 323         if (lck->lockx.in.mode & LOCKING_ANDX_SHARED_LOCK) {
 324                 rw = pending? PENDING_READ_LOCK : READ_LOCK;
 325         } else {
 326                 rw = pending? PENDING_WRITE_LOCK : WRITE_LOCK;
 327         }
 328
 329         if (lck->lockx.in.mode & LOCKING_ANDX_CANCEL_LOCK) {
 330                 talloc_free(pending);
 331                 return pvfs_lock_cancel(pvfs, req, lck, f);
 332         }
 333
 334         if (lck->lockx.in.mode & LOCKING_ANDX_CHANGE_LOCKTYPE) {
 335                 /* this seems to not be supported by any windows server,
 336                    or used by any clients */
 337                 talloc_free(pending);
 338                 return NT_STATUS_DOS(ERRDOS, ERRnoatomiclocks);
 339         }
 340
 341         /* the unlocks happen first */
 342         locks = lck->lockx.in.locks;
 343
 344         for (i=0;i<lck->lockx.in.ulock_cnt;i++) {
 345                 status = brlock_unlock(pvfs->brl_context,
 346                                     f->brl_handle,
 347                                     locks[i].pid,
 348                                     locks[i].offset,
 349                                     locks[i].count);
 350                 if (!NT_STATUS_IS_OK(status)) {
 351                         talloc_free(pending);
 352                         return status;
 353                 }
 354                 f->lock_count--;
 355         }
 356
 357         locks += i;
 358
 359         for (i=0;i<lck->lockx.in.lock_cnt;i++) {
 360                 if (pending) {
 361                         pending->pending_lock = i;
 362                 }
 363
 364                 status = brlock_lock(pvfs->brl_context,
 365                                   f->brl_handle,
 366                                   locks[i].pid,
 367                                   locks[i].offset,
 368                                   locks[i].count,
 369                                   rw, pending);
 370                 if (!NT_STATUS_IS_OK(status)) {
 371                         if (pending) {
 372                                 /* a timed lock failed - setup a wait message to handle
 373                                    the pending lock notification or a timeout */
 374                                 pending->wait_handle = pvfs_wait_message(pvfs, req, MSG_BRL_RETRY,
 375                                                                          pending->end_time,
 376                                                                          pvfs_pending_lock_continue,
 377                                                                          pending);
 378                                 if (pending->wait_handle == NULL) {
 379                                         talloc_free(pending);
 380                                         return NT_STATUS_NO_MEMORY;
 381                                 }
 382                                 talloc_steal(pending, pending->wait_handle);
 383                                 DLIST_ADD(f->pending_list, pending);
 384                                 return NT_STATUS_OK;
 385                         }
 386
 387                         /* undo the locks we just did */
 388                         for (i--;i>=0;i--) {
 389                                 brlock_unlock(pvfs->brl_context,
 390                                            f->brl_handle,
 391                                            locks[i].pid,
 392                                            locks[i].offset,
 393                                            locks[i].count);
 394                                 f->lock_count--;
 395                         }
 396                         talloc_free(pending);
 397                         return status;
 398                 }
 399                 f->lock_count++;
 400         }
 401
 402         talloc_free(pending);
 403         return NT_STATUS_OK;
 404 }