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                          uint16_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 brl_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         void *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         /* in SMB2 mode we also try to unlock failing lock */
  72         if (req->ctx->protocol != PROTOCOL_SMB2) {
  73                 i--;
  74         }
  75
  76         /* undo the locks we just did */
  77         for (;i>=0;i--) {
  78                 brl_unlock(pvfs->brl_context,
  79                            f->brl_handle,
  80                            locks[i].pid,
  81                            locks[i].offset,
  82                            locks[i].count);
  83                 f->lock_count--;
  84         }
  85         req->async_states->status = status;
  86         req->async_states->send_fn(req);
  87 }
  88
  89
  90 /*
  91   called when we receive a pending lock notification. It means that
  92   either our lock timed out or someone else has unlocked a overlapping
  93   range, so we should try the lock again. Note that on timeout we
  94   do retry the lock, giving it a last chance.
  95 */
  96 static void pvfs_pending_lock_continue(void *private, enum pvfs_wait_notice reason)
  97 {
  98         struct pvfs_pending_lock *pending = private;
  99         struct pvfs_state *pvfs = pending->pvfs;
 100         struct pvfs_file *f = pending->f;
 101         struct ntvfs_request *req = pending->req;
 102         union smb_lock *lck = pending->lck;
 103         struct smb_lock_entry *locks;
 104         enum brl_type rw;
 105         NTSTATUS status;
 106         int i;
 107         BOOL timed_out;
 108
 109         timed_out = (reason != PVFS_WAIT_EVENT);
 110
 111         locks = lck->lockx.in.locks + lck->lockx.in.ulock_cnt;
 112
 113         if (lck->lockx.in.mode & LOCKING_ANDX_SHARED_LOCK) {
 114                 rw = READ_LOCK;
 115         } else {
 116                 rw = WRITE_LOCK;
 117         }
 118
 119         DLIST_REMOVE(f->pending_list, pending);
 120
 121         /* we don't retry on a cancel */
 122         if (reason == PVFS_WAIT_CANCEL) {
 123                 status = NT_STATUS_FILE_LOCK_CONFLICT;
 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 = brl_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 = brl_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                 } else {
 159                         /* we can try again */
 160                         DLIST_ADD(f->pending_list, pending);
 161                 }
 162                 return;
 163         }
 164
 165         /* if we haven't timed out yet, then we can do more pending locks */
 166         if (rw == READ_LOCK) {
 167                 rw = PENDING_READ_LOCK;
 168         } else {
 169                 rw = PENDING_WRITE_LOCK;
 170         }
 171
 172         /* we've now got the pending lock. try and get the rest, which might
 173            lead to more pending locks */
 174         for (i=pending->pending_lock+1;i<lck->lockx.in.lock_cnt;i++) {
 175                 if (pending) {
 176                         pending->pending_lock = i;
 177                 }
 178
 179                 status = brl_lock(pvfs->brl_context,
 180                                   f->brl_handle,
 181                                   locks[i].pid,
 182                                   locks[i].offset,
 183                                   locks[i].count,
 184                                   rw, pending);
 185                 if (!NT_STATUS_IS_OK(status)) {
 186                         if (pending) {
 187                                 /* a timed lock failed - setup a wait message to handle
 188                                    the pending lock notification or a timeout */
 189                                 pending->wait_handle = pvfs_wait_message(pvfs, req, MSG_BRL_RETRY,
 190                                                                          pending->end_time,
 191                                                                          pvfs_pending_lock_continue,
 192                                                                          pending);
 193                                 if (pending->wait_handle == NULL) {
 194                                         pvfs_lock_async_failed(pvfs, req, f, locks, i, NT_STATUS_NO_MEMORY);
 195                                 } else {
 196                                         talloc_steal(pending, pending->wait_handle);
 197                                         DLIST_ADD(f->pending_list, pending);
 198                                 }
 199                                 return;
 200                         }
 201                         pvfs_lock_async_failed(pvfs, req, f, locks, i, status);
 202                         return;
 203                 }
 204
 205                 f->lock_count++;
 206         }
 207
 208         /* we've managed to get all the locks. Tell the client */
 209         req->async_states->status = NT_STATUS_OK;
 210         req->async_states->send_fn(req);
 211 }
 212
 213
 214 /*
 215   called when we close a file that might have locks
 216 */
 217 void pvfs_lock_close(struct pvfs_state *pvfs, struct pvfs_file *f)
 218 {
 219         struct pvfs_pending_lock *p, *next;
 220
 221         if (f->lock_count || f->pending_list) {
 222                 DEBUG(5,("pvfs_lock: removing %.0f locks on close\n",
 223                          (double)f->lock_count));
 224                 brl_close(f->pvfs->brl_context, f->brl_handle);
 225                 f->lock_count = 0;
 226         }
 227
 228         /* reply to all the pending lock requests, telling them the
 229            lock failed */
 230         for (p=f->pending_list;p;p=next) {
 231                 next = p->next;
 232                 DLIST_REMOVE(f->pending_list, p);
 233                 p->req->async_states->status = NT_STATUS_RANGE_NOT_LOCKED;
 234                 p->req->async_states->send_fn(p->req);
 235         }
 236 }
 237
 238
 239 /*
 240   cancel a set of locks
 241 */
 242 static NTSTATUS pvfs_lock_cancel(struct pvfs_state *pvfs, struct ntvfs_request *req, union smb_lock *lck,
 243                                  struct pvfs_file *f)
 244 {
 245         struct pvfs_pending_lock *p;
 246
 247         for (p=f->pending_list;p;p=p->next) {
 248                 /* check if the lock request matches exactly - you can only cancel with exact matches */
 249                 if (p->lck->lockx.in.ulock_cnt == lck->lockx.in.ulock_cnt &&
 250                     p->lck->lockx.in.lock_cnt  == lck->lockx.in.lock_cnt &&
 251                     p->lck->lockx.in.file.ntvfs== lck->lockx.in.file.ntvfs &&
 252                     p->lck->lockx.in.mode      == (lck->lockx.in.mode & ~LOCKING_ANDX_CANCEL_LOCK)) {
 253                         int i;
 254
 255                         for (i=0;i<lck->lockx.in.ulock_cnt + lck->lockx.in.lock_cnt;i++) {
 256                                 if (p->lck->lockx.in.locks[i].pid != lck->lockx.in.locks[i].pid ||
 257                                     p->lck->lockx.in.locks[i].offset != lck->lockx.in.locks[i].offset ||
 258                                     p->lck->lockx.in.locks[i].count != lck->lockx.in.locks[i].count) {
 259                                         break;
 260                                 }
 261                         }
 262                         if (i < lck->lockx.in.ulock_cnt) continue;
 263
 264                         /* an exact match! we can cancel it, which is equivalent
 265                            to triggering the timeout early */
 266                         pvfs_pending_lock_continue(p, PVFS_WAIT_TIMEOUT);
 267                         return NT_STATUS_OK;
 268                 }
 269         }
 270
 271         return NT_STATUS_DOS(ERRDOS, ERRcancelviolation);
 272 }
 273
 274
 275 /*
 276   lock or unlock a byte range
 277 */
 278 NTSTATUS pvfs_lock(struct ntvfs_module_context *ntvfs,
 279                    struct ntvfs_request *req, union smb_lock *lck)
 280 {
 281         struct pvfs_state *pvfs = ntvfs->private_data;
 282         struct pvfs_file *f;
 283         struct smb_lock_entry *locks;
 284         int i;
 285         enum brl_type rw;
 286         struct pvfs_pending_lock *pending = NULL;
 287         NTSTATUS status;
 288
 289         if (lck->generic.level != RAW_LOCK_GENERIC) {
 290                 return ntvfs_map_lock(ntvfs, req, lck);
 291         }
 292
 293         f = pvfs_find_fd(pvfs, req, lck->lockx.in.file.ntvfs);
 294         if (!f) {
 295                 return NT_STATUS_INVALID_HANDLE;
 296         }
 297
 298         if (f->handle->fd == -1) {
 299                 return NT_STATUS_FILE_IS_A_DIRECTORY;
 300         }
 301
 302         if (lck->lockx.in.timeout != 0 &&
 303             (req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
 304                 pending = talloc(f, struct pvfs_pending_lock);
 305                 if (pending == NULL) {
 306                         return NT_STATUS_NO_MEMORY;
 307                 }
 308
 309                 pending->pvfs = pvfs;
 310                 pending->lck = lck;
 311                 pending->f = f;
 312                 pending->req = req;
 313
 314                 pending->end_time =
 315                         timeval_current_ofs(lck->lockx.in.timeout/1000,
 316                                             1000*(lck->lockx.in.timeout%1000));
 317         }
 318
 319         if (lck->lockx.in.mode & LOCKING_ANDX_SHARED_LOCK) {
 320                 rw = pending? PENDING_READ_LOCK : READ_LOCK;
 321         } else {
 322                 rw = pending? PENDING_WRITE_LOCK : WRITE_LOCK;
 323         }
 324
 325         if (lck->lockx.in.mode & LOCKING_ANDX_CANCEL_LOCK) {
 326                 return pvfs_lock_cancel(pvfs, req, lck, f);
 327         }
 328
 329         if (lck->lockx.in.mode & LOCKING_ANDX_CHANGE_LOCKTYPE) {
 330                 /* this seems to not be supported by any windows server,
 331                    or used by any clients */
 332                 return NT_STATUS_DOS(ERRDOS, ERRnoatomiclocks);
 333         }
 334
 335         if (lck->lockx.in.mode & LOCKING_ANDX_OPLOCK_RELEASE) {
 336                 DEBUG(0,("received unexpected oplock break\n"));
 337                 return NT_STATUS_NOT_IMPLEMENTED;
 338         }
 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 = brl_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                         return status;
 352                 }
 353                 f->lock_count--;
 354         }
 355
 356         locks += i;
 357
 358         for (i=0;i<lck->lockx.in.lock_cnt;i++) {
 359                 if (pending) {
 360                         pending->pending_lock = i;
 361                 }
 362
 363                 status = brl_lock(pvfs->brl_context,
 364                                   f->brl_handle,
 365                                   locks[i].pid,
 366                                   locks[i].offset,
 367                                   locks[i].count,
 368                                   rw, pending);
 369                 if (!NT_STATUS_IS_OK(status)) {
 370                         if (pending) {
 371                                 /* a timed lock failed - setup a wait message to handle
 372                                    the pending lock notification or a timeout */
 373                                 pending->wait_handle = pvfs_wait_message(pvfs, req, MSG_BRL_RETRY,
 374                                                                          pending->end_time,
 375                                                                          pvfs_pending_lock_continue,
 376                                                                          pending);
 377                                 if (pending->wait_handle == NULL) {
 378                                         return NT_STATUS_NO_MEMORY;
 379                                 }
 380                                 talloc_steal(pending, pending->wait_handle);
 381                                 DLIST_ADD(f->pending_list, pending);
 382                                 return NT_STATUS_OK;
 383                         }
 384                         /* in SMB2 mode we also try to unlock failing lock */
 385                         if (req->ctx->protocol != PROTOCOL_SMB2) {
 386                                 i--;
 387                         }
 388                         /* undo the locks we just did */
 389                         for (;i>=0;i--) {
 390                                 brl_unlock(pvfs->brl_context,
 391                                            f->brl_handle,
 392                                            locks[i].pid,
 393                                            locks[i].offset,
 394                                            locks[i].count);
 395                                 f->lock_count--;
 396                         }
 397                         return status;
 398                 }
 399                 f->lock_count++;
 400         }
 401
 402         return NT_STATUS_OK;
 403 }