2 Unix SMB/Netbios implementation.
4 read/write to a files_struct
5 Copyright (C) Andrew Tridgell 1992-1998
6 Copyright (C) Jeremy Allison 2000-2002. - write cache.
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.
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.
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/>.
23 #include "smbd/globals.h"
25 static bool setup_write_cache(files_struct *, SMB_OFF_T);
27 /****************************************************************************
28 Read from write cache if we can.
29 ****************************************************************************/
31 static bool read_from_write_cache(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
33 write_cache *wcp = fsp->wcp;
39 if( n > wcp->data_size || pos < wcp->offset || pos + n > wcp->offset + wcp->data_size) {
43 memcpy(data, wcp->data + (pos - wcp->offset), n);
45 DO_PROFILE_INC(writecache_read_hits);
50 /****************************************************************************
52 ****************************************************************************/
54 ssize_t read_file(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
56 ssize_t ret=0,readret;
58 /* you can't read from print files */
59 if (fsp->print_file) {
64 * Serve from write cache if we can.
67 if(read_from_write_cache(fsp, data, pos, n)) {
68 fsp->fh->pos = pos + n;
69 fsp->fh->position_information = fsp->fh->pos;
73 flush_write_cache(fsp, READ_FLUSH);
81 readret = SMB_VFS_PREAD(fsp,data,n,pos);
84 if ((errno == EAGAIN) && numretries) {
85 DEBUG(3,("read_file EAGAIN retry in 10 seconds\n"));
92 #else /* NO DMF fix. */
93 readret = SMB_VFS_PREAD(fsp,data,n,pos);
104 DEBUG(10,("read_file (%s): pos = %.0f, size = %lu, returned %lu\n",
105 fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
108 fsp->fh->position_information = fsp->fh->pos;
113 /****************************************************************************
114 *Really* write to a file.
115 ****************************************************************************/
117 static ssize_t real_write_file(struct smb_request *req,
126 ret = vfs_write_data(req, fsp, data, n);
129 if (pos && lp_strict_allocate(SNUM(fsp->conn))) {
130 if (vfs_fill_sparse(fsp, pos) == -1) {
134 ret = vfs_pwrite_data(req, fsp, data, n, pos);
137 DEBUG(10,("real_write_file (%s): pos = %.0f, size = %lu, returned %ld\n",
138 fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
143 /* Yes - this is correct - writes don't update this. JRA. */
144 /* Found by Samba4 tests. */
146 fsp->position_information = fsp->pos;
153 /****************************************************************************
154 File size cache change.
155 Updates size on disk but doesn't flush the cache.
156 ****************************************************************************/
158 static int wcp_file_size_change(files_struct *fsp)
161 write_cache *wcp = fsp->wcp;
163 wcp->file_size = wcp->offset + wcp->data_size;
164 ret = SMB_VFS_FTRUNCATE(fsp, wcp->file_size);
166 DEBUG(0,("wcp_file_size_change (%s): ftruncate of size %.0f error %s\n",
167 fsp->fsp_name, (double)wcp->file_size, strerror(errno) ));
172 static void update_write_time_handler(struct event_context *ctx,
173 struct timed_event *te,
177 files_struct *fsp = (files_struct *)private_data;
179 /* Remove the timed event handler. */
180 TALLOC_FREE(fsp->update_write_time_event);
181 DEBUG(5, ("Update write time on %s\n", fsp->fsp_name));
183 /* change the write time if not already changed by someone else */
184 update_write_time(fsp);
187 /*********************************************************
188 Schedule a write time update for WRITE_TIME_UPDATE_USEC_DELAY
190 *********************************************************/
192 void trigger_write_time_update(struct files_struct *fsp)
196 if (fsp->write_time_forced) {
197 /* No point - "sticky" write times
203 if (fsp->update_write_time_triggered) {
205 * We only update the write time
206 * on the first write. After that
207 * no other writes affect this.
211 fsp->update_write_time_triggered = true;
213 delay = lp_parm_int(SNUM(fsp->conn),
214 "smbd", "writetimeupdatedelay",
215 WRITE_TIME_UPDATE_USEC_DELAY);
217 /* trigger the update 2 seconds later */
218 fsp->update_write_time_on_close = true;
219 fsp->update_write_time_event =
220 event_add_timed(smbd_event_context(), NULL,
221 timeval_current_ofs(0, delay),
222 update_write_time_handler, fsp);
225 void trigger_write_time_update_immediate(struct files_struct *fsp)
227 if (fsp->write_time_forced) {
229 * No point - "sticky" write times
235 TALLOC_FREE(fsp->update_write_time_event);
236 DEBUG(5, ("Update write time immediate on %s\n", fsp->fsp_name));
238 fsp->update_write_time_triggered = true;
240 fsp->update_write_time_on_close = false;
241 update_write_time(fsp);
244 /****************************************************************************
246 ****************************************************************************/
248 ssize_t write_file(struct smb_request *req,
254 write_cache *wcp = fsp->wcp;
255 ssize_t total_written = 0;
258 if (fsp->print_file) {
262 if (!rap_to_pjobid(fsp->rap_print_jobid, sharename, &jobid)) {
263 DEBUG(3,("write_file: Unable to map RAP jobid %u to jobid.\n",
264 (unsigned int)fsp->rap_print_jobid ));
269 return print_job_write(SNUM(fsp->conn), jobid, data, pos, n);
272 if (!fsp->can_write) {
277 if (!fsp->modified) {
279 fsp->modified = True;
281 if (SMB_VFS_FSTAT(fsp, &st) == 0) {
283 trigger_write_time_update(fsp);
284 dosmode = dos_mode(fsp->conn,fsp->fsp_name,&st);
285 if ((lp_store_dos_attributes(SNUM(fsp->conn)) ||
286 MAP_ARCHIVE(fsp->conn)) &&
287 !IS_DOS_ARCHIVE(dosmode)) {
288 file_set_dosmode(fsp->conn,fsp->fsp_name,
295 * If this is the first write and we have an exclusive oplock then setup
299 if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && !wcp) {
300 setup_write_cache(fsp, st.st_size);
307 DO_PROFILE_INC(writecache_total_writes);
308 if (!fsp->oplock_type) {
309 DO_PROFILE_INC(writecache_non_oplock_writes);
314 * If this file is level II oplocked then we need
315 * to grab the shared memory lock and inform all
316 * other files with a level II lock that they need
317 * to flush their read caches. We keep the lock over
318 * the shared memory area whilst doing this.
321 release_level_2_oplocks_on_change(fsp);
324 if (profile_p && profile_p->writecache_total_writes % 500 == 0) {
325 DEBUG(3,("WRITECACHE: initwrites=%u abutted=%u total=%u \
326 nonop=%u allocated=%u active=%u direct=%u perfect=%u readhits=%u\n",
327 profile_p->writecache_init_writes,
328 profile_p->writecache_abutted_writes,
329 profile_p->writecache_total_writes,
330 profile_p->writecache_non_oplock_writes,
331 profile_p->writecache_allocated_write_caches,
332 profile_p->writecache_num_write_caches,
333 profile_p->writecache_direct_writes,
334 profile_p->writecache_num_perfect_writes,
335 profile_p->writecache_read_hits ));
337 DEBUG(3,("WRITECACHE: Flushes SEEK=%d, READ=%d, WRITE=%d, READRAW=%d, OPLOCK=%d, CLOSE=%d, SYNC=%d\n",
338 profile_p->writecache_flushed_writes[SEEK_FLUSH],
339 profile_p->writecache_flushed_writes[READ_FLUSH],
340 profile_p->writecache_flushed_writes[WRITE_FLUSH],
341 profile_p->writecache_flushed_writes[READRAW_FLUSH],
342 profile_p->writecache_flushed_writes[OPLOCK_RELEASE_FLUSH],
343 profile_p->writecache_flushed_writes[CLOSE_FLUSH],
344 profile_p->writecache_flushed_writes[SYNC_FLUSH] ));
348 if (wcp && req->unread_bytes) {
349 /* If we're using receivefile don't
350 * deal with a write cache.
352 flush_write_cache(fsp, WRITE_FLUSH);
353 delete_write_cache(fsp);
358 DO_PROFILE_INC(writecache_direct_writes);
359 total_written = real_write_file(req, fsp, data, pos, n);
360 return total_written;
363 DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f wcp->data_size=%u\n",
364 fsp->fsp_name, fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size));
366 fsp->fh->pos = pos + n;
369 * If we have active cache and it isn't contiguous then we flush.
370 * NOTE: There is a small problem with running out of disk ....
373 if (wcp->data_size) {
374 bool cache_flush_needed = False;
376 if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
378 /* ASCII art.... JRA.
380 +--------------+-----
381 | Cached data | Rest of allocated cache buffer....
382 +--------------+-----
384 +-------------------+
386 +-------------------+
391 * Start of write overlaps or abutts the existing data.
394 size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
396 memcpy(wcp->data + (pos - wcp->offset), data, data_used);
399 * Update the current buffer size with the new data.
402 if(pos + data_used > wcp->offset + wcp->data_size) {
403 wcp->data_size = pos + data_used - wcp->offset;
407 * Update the file size if changed.
410 if (wcp->offset + wcp->data_size > wcp->file_size) {
411 if (wcp_file_size_change(fsp) == -1) {
417 * If we used all the data then
424 cache_flush_needed = True;
427 * Move the start of data forward by the amount used,
428 * cut down the amount left by the same amount.
435 DO_PROFILE_INC(writecache_abutted_writes);
436 total_written = data_used;
440 } else if ((pos < wcp->offset) && (pos + n > wcp->offset) &&
441 (pos + n <= wcp->offset + wcp->alloc_size)) {
443 /* ASCII art.... JRA.
449 +-------------------+
451 +-------------------+
456 * End of write overlaps the existing data.
459 size_t data_used = pos + n - wcp->offset;
461 memcpy(wcp->data, data + n - data_used, data_used);
464 * Update the current buffer size with the new data.
467 if(pos + n > wcp->offset + wcp->data_size) {
468 wcp->data_size = pos + n - wcp->offset;
472 * Update the file size if changed.
475 if (wcp->offset + wcp->data_size > wcp->file_size) {
476 if (wcp_file_size_change(fsp) == -1) {
482 * We don't need to move the start of data, but we
483 * cut down the amount left by the amount used.
489 * We cannot have used all the data here.
492 cache_flush_needed = True;
494 DO_PROFILE_INC(writecache_abutted_writes);
495 total_written = data_used;
499 } else if ( (pos >= wcp->file_size) &&
500 (wcp->offset + wcp->data_size == wcp->file_size) &&
501 (pos > wcp->offset + wcp->data_size) &&
502 (pos < wcp->offset + wcp->alloc_size) ) {
504 /* ASCII art.... JRA.
508 +---------------+---------------+
509 | Cached data | Cache buffer |
510 +---------------+---------------+
512 +-------------------+
514 +-------------------+
519 * Non-contiguous write part of which fits within
520 * the cache buffer and is extending the file
521 * and the cache contents reflect the current
522 * data up to the current end of the file.
527 if(pos + n <= wcp->offset + wcp->alloc_size) {
530 data_used = wcp->offset + wcp->alloc_size - pos;
534 * Fill in the non-continuous area with zeros.
537 memset(wcp->data + wcp->data_size, '\0',
538 pos - (wcp->offset + wcp->data_size) );
540 memcpy(wcp->data + (pos - wcp->offset), data, data_used);
543 * Update the current buffer size with the new data.
546 if(pos + data_used > wcp->offset + wcp->data_size) {
547 wcp->data_size = pos + data_used - wcp->offset;
551 * Update the file size if changed.
554 if (wcp->offset + wcp->data_size > wcp->file_size) {
555 if (wcp_file_size_change(fsp) == -1) {
561 * If we used all the data then
568 cache_flush_needed = True;
572 * Move the start of data forward by the amount used,
573 * cut down the amount left by the same amount.
580 DO_PROFILE_INC(writecache_abutted_writes);
581 total_written = data_used;
585 } else if ( (pos >= wcp->file_size) &&
587 (wcp->file_size == wcp->offset + wcp->data_size) &&
588 (pos < wcp->file_size + wcp->alloc_size)) {
594 +---------------+---------------+
595 | Cached data | Cache buffer |
596 +---------------+---------------+
598 |<------- allocated size ---------------->|
604 MS-Office seems to do this a lot to determine if there's enough
605 space on the filesystem to write a new file.
610 +-----------------------+--------+
611 | Zeroed Cached data | 1 Byte |
612 +-----------------------+--------+
615 flush_write_cache(fsp, WRITE_FLUSH);
616 wcp->offset = wcp->file_size;
617 wcp->data_size = pos - wcp->file_size + 1;
618 memset(wcp->data, '\0', wcp->data_size);
619 memcpy(wcp->data + wcp->data_size-1, data, 1);
622 * Update the file size if changed.
625 if (wcp->offset + wcp->data_size > wcp->file_size) {
626 if (wcp_file_size_change(fsp) == -1) {
635 /* ASCII art..... JRA.
639 +---------------+---------------+
640 | Cached data | Cache buffer |
641 +---------------+---------------+
643 +-------------------+
645 +-------------------+
649 +---------------+---------------+
650 | Cached data | Cache buffer |
651 +---------------+---------------+
653 +-------------------+
655 +-------------------+
659 +---------------+---------------+
660 | Cached data | Cache buffer |
661 +---------------+---------------+
663 +-----------------------------------------------------+
665 +-----------------------------------------------------+
670 * Write is bigger than buffer, or there is no overlap on the
674 DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
675 len = %u\n",fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
678 * If write would fit in the cache, and is larger than
679 * the data already in the cache, flush the cache and
680 * preferentially copy the data new data into it. Otherwise
681 * just write the data directly.
684 if ( n <= wcp->alloc_size && n > wcp->data_size) {
685 cache_flush_needed = True;
687 ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
690 * If the write overlaps the entire cache, then
691 * discard the current contents of the cache.
692 * Fix from Rasmus Borup Hansen rbh@math.ku.dk.
695 if ((pos <= wcp->offset) &&
696 (pos + n >= wcp->offset + wcp->data_size) ) {
697 DEBUG(9,("write_file: discarding overwritten write \
698 cache: fd = %d, off=%.0f, size=%u\n", fsp->fh->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
702 DO_PROFILE_INC(writecache_direct_writes);
707 if (pos + ret > wcp->file_size) {
708 wcp->file_size = pos + ret;
718 if (cache_flush_needed) {
719 DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
720 n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
721 write_path, fsp->fh->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
722 (double)wcp->offset, (unsigned int)wcp->data_size ));
724 flush_write_cache(fsp, WRITE_FLUSH);
729 * If the write request is bigger than the cache
730 * size, write it all out.
733 if (n > wcp->alloc_size ) {
734 ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
739 if (pos + ret > wcp->file_size) {
740 wcp->file_size = pos + n;
743 DO_PROFILE_INC(writecache_direct_writes);
744 return total_written + n;
748 * If there's any data left, cache it.
753 if (wcp->data_size) {
754 DO_PROFILE_INC(writecache_abutted_writes);
756 DO_PROFILE_INC(writecache_init_writes);
759 memcpy(wcp->data+wcp->data_size, data, n);
760 if (wcp->data_size == 0) {
762 DO_PROFILE_INC(writecache_num_write_caches);
767 * Update the file size if changed.
770 if (wcp->offset + wcp->data_size > wcp->file_size) {
771 if (wcp_file_size_change(fsp) == -1) {
775 DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
776 (double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
779 return total_written; /* .... that's a write :) */
782 return total_written;
785 /****************************************************************************
786 Delete the write cache structure.
787 ****************************************************************************/
789 void delete_write_cache(files_struct *fsp)
797 if(!(wcp = fsp->wcp)) {
801 DO_PROFILE_DEC(writecache_allocated_write_caches);
802 allocated_write_caches--;
804 SMB_ASSERT(wcp->data_size == 0);
806 SAFE_FREE(wcp->data);
809 DEBUG(10,("delete_write_cache: File %s deleted write cache\n", fsp->fsp_name ));
812 /****************************************************************************
813 Setup the write cache structure.
814 ****************************************************************************/
816 static bool setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
818 ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
821 if (allocated_write_caches >= MAX_WRITE_CACHES) {
825 if(alloc_size == 0 || fsp->wcp) {
829 if((wcp = SMB_MALLOC_P(write_cache)) == NULL) {
830 DEBUG(0,("setup_write_cache: malloc fail.\n"));
834 wcp->file_size = file_size;
836 wcp->alloc_size = alloc_size;
838 if((wcp->data = (char *)SMB_MALLOC(wcp->alloc_size)) == NULL) {
839 DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
840 (unsigned int)wcp->alloc_size ));
845 memset(wcp->data, '\0', wcp->alloc_size );
848 DO_PROFILE_INC(writecache_allocated_write_caches);
849 allocated_write_caches++;
851 DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n",
852 fsp->fsp_name, (unsigned long)wcp->alloc_size ));
857 /****************************************************************************
858 Cope with a size change.
859 ****************************************************************************/
861 void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
864 /* The cache *must* have been flushed before we do this. */
865 if (fsp->wcp->data_size != 0) {
867 if (asprintf(&msg, "set_filelen_write_cache: size change "
868 "on file %s with write cache size = %lu\n",
870 (unsigned long)fsp->wcp->data_size) != -1) {
873 smb_panic("set_filelen_write_cache");
876 fsp->wcp->file_size = file_size;
880 /*******************************************************************
881 Flush a write cache struct to disk.
882 ********************************************************************/
884 ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
886 write_cache *wcp = fsp->wcp;
890 if(!wcp || !wcp->data_size) {
894 data_size = wcp->data_size;
897 DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
899 DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
900 fsp->fh->fd, (double)wcp->offset, (unsigned int)data_size));
903 if(data_size == wcp->alloc_size) {
904 DO_PROFILE_INC(writecache_num_perfect_writes);
908 ret = real_write_file(NULL, fsp, wcp->data, wcp->offset, data_size);
911 * Ensure file size if kept up to date if write extends file.
914 if ((ret != -1) && (wcp->offset + ret > wcp->file_size)) {
915 wcp->file_size = wcp->offset + ret;
921 /*******************************************************************
923 ********************************************************************/
925 NTSTATUS sync_file(connection_struct *conn, files_struct *fsp, bool write_through)
927 if (fsp->fh->fd == -1)
928 return NT_STATUS_INVALID_HANDLE;
930 if (lp_strict_sync(SNUM(conn)) &&
931 (lp_syncalways(SNUM(conn)) || write_through)) {
932 int ret = flush_write_cache(fsp, SYNC_FLUSH);
934 return map_nt_error_from_unix(errno);
936 ret = SMB_VFS_FSYNC(fsp);
938 return map_nt_error_from_unix(errno);
944 /************************************************************
945 Perform a stat whether a valid fd or not.
946 ************************************************************/
948 int fsp_stat(files_struct *fsp, SMB_STRUCT_STAT *pst)
950 if (fsp->fh->fd == -1) {
951 return SMB_VFS_STAT(fsp->conn, fsp->fsp_name, pst);
953 return SMB_VFS_FSTAT(fsp, pst);