summaryrefslogtreecommitdiff
path: root/source3/modules/onefs_system.c
blob: 46f38265b1689de34f9c84e802c7f3bdcc2b740b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
/*
 * Unix SMB/CIFS implementation.
 * Support for OneFS system interfaces.
 *
 * Copyright (C) Tim Prouty, 2008
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#include "includes.h"
#include "onefs.h"
#include "onefs_config.h"
#include "oplock_onefs.h"

#include <ifs/ifs_syscalls.h>
#include <isi_acl/isi_acl_util.h>
#include <sys/isi_acl.h>

/*
 * Initialize the sm_lock struct before passing it to ifs_createfile.
 */
static void smlock_init(connection_struct *conn, struct sm_lock *sml,
    bool isexe, uint32_t access_mask, uint32_t share_access,
    uint32_t create_options)
{
	sml->sm_type.doc = false;
	sml->sm_type.isexe = isexe;
	sml->sm_type.statonly = is_stat_open(access_mask);
	sml->sm_type.access_mask = access_mask;
	sml->sm_type.share_access = share_access;

	/*
	 * private_options was previously used for DENY_DOS/DENY_FCB checks in
	 * the kernel, but are now properly handled by fcb_or_dos_open. In
	 * these cases, ifs_createfile will return a sharing violation, which
	 * gives fcb_or_dos_open the chance to open a duplicate file handle.
	 */
	sml->sm_type.private_options = 0;

	/* 1 second delay is handled in onefs_open.c by deferring the open */
	sml->sm_timeout = timeval_set(0, 0);
}

static void smlock_dump(int debuglevel, const struct sm_lock *sml)
{
	if (sml == NULL) {
		DEBUG(debuglevel, ("sml == NULL\n"));
		return;
	}

	DEBUG(debuglevel,
	      ("smlock: doc=%s, isexec=%s, statonly=%s, access_mask=0x%x, "
	       "share_access=0x%x, private_options=0x%x timeout=%d/%d\n",
	       sml->sm_type.doc ? "True" : "False",
	       sml->sm_type.isexe ? "True" : "False",
	       sml->sm_type.statonly ? "True" : "False",
	       sml->sm_type.access_mask,
	       sml->sm_type.share_access,
	       sml->sm_type.private_options,
	       (int)sml->sm_timeout.tv_sec,
	       (int)sml->sm_timeout.tv_usec));
}

/**
 * External interface to ifs_createfile
 */
int onefs_sys_create_file(connection_struct *conn,
			  int base_fd,
			  const char *path,
		          uint32_t access_mask,
		          uint32_t open_access_mask,
			  uint32_t share_access,
			  uint32_t create_options,
			  int flags,
			  mode_t mode,
			  int oplock_request,
			  uint64_t id,
			  struct security_descriptor *sd,
			  uint32_t dos_flags,
			  int *granted_oplock)
{
	struct sm_lock sml, *psml = NULL;
	enum oplock_type onefs_oplock;
	enum oplock_type onefs_granted_oplock = OPLOCK_NONE;
	struct ifs_security_descriptor ifs_sd = {}, *pifs_sd = NULL;
	int secinfo = 0;
	int ret_fd = -1;
	uint32_t onefs_dos_attributes;
	struct ifs_createfile_flags cf_flags = CF_FLAGS_NONE;

	START_PROFILE(syscall_createfile);

	/* Setup security descriptor and get secinfo. */
	if (sd != NULL) {
		NTSTATUS status;

		secinfo = (get_sec_info(sd) & IFS_SEC_INFO_KNOWN_MASK);

		status = onefs_samba_sd_to_sd(secinfo, sd, &ifs_sd, SNUM(conn));

		if (!NT_STATUS_IS_OK(status)) {
			DEBUG(1, ("SD initialization failure: %s",
				  nt_errstr(status)));
			errno = EINVAL;
			goto out;
		}

		pifs_sd = &ifs_sd;
	}

	/* Stripping off private bits will be done for us. */
	onefs_oplock = onefs_samba_oplock_to_oplock(oplock_request);

	if (!lp_oplocks(SNUM(conn))) {
		SMB_ASSERT(onefs_oplock == OPLOCK_NONE);
	}

	/* Convert samba dos flags to UF_DOS_* attributes. */
	onefs_dos_attributes = dos_attributes_to_stat_dos_flags(dos_flags);

	/**
	 * Deal with kernel creating Default ACLs. (Isilon bug 47447.)
	 *
	 * 1) "nt acl support = no", default_acl = no
	 * 2) "inherit permissions = yes", default_acl = no
	 */
	if (lp_nt_acl_support(SNUM(conn)) && !lp_inherit_perms(SNUM(conn)))
		cf_flags = cf_flags_or(cf_flags, CF_FLAGS_DEFAULT_ACL);

	/*
	 * Some customer workflows require the execute bit to be ignored.
	 */
	if (lp_parm_bool(SNUM(conn), PARM_ONEFS_TYPE,
			 PARM_ALLOW_EXECUTE_ALWAYS,
			 PARM_ALLOW_EXECUTE_ALWAYS_DEFAULT) &&
	    (open_access_mask & FILE_EXECUTE)) {

		DEBUG(3, ("Stripping execute bit from %s: (0x%x)\n", path,
			  open_access_mask));

		/* Strip execute. */
		open_access_mask &= ~FILE_EXECUTE;

		/*
		 * Add READ_DATA, so we're not left with desired_access=0. An
		 * execute call should imply the client will read the data.
		 */
		open_access_mask |= FILE_READ_DATA;

		DEBUGADD(3, ("New stripped access mask: 0x%x\n",
			     open_access_mask));
	}

	DEBUG(10,("onefs_sys_create_file: base_fd = %d, "
		  "open_access_mask = 0x%x, flags = 0x%x, mode = 0%o, "
		  "desired_oplock = %s, id = 0x%x, secinfo = 0x%x, sd = %p, "
		  "dos_attributes = 0x%x, path = %s, "
		  "default_acl=%s\n", base_fd,
		  (unsigned int)open_access_mask,
		  (unsigned int)flags,
		  (unsigned int)mode,
		  onefs_oplock_str(onefs_oplock),
		  (unsigned int)id,
		  (unsigned int)secinfo, sd,
		  (unsigned int)onefs_dos_attributes, path,
		  cf_flags_and_bool(cf_flags, CF_FLAGS_DEFAULT_ACL) ?
		      "true" : "false"));

	/* Initialize smlock struct for files/dirs but not internal opens */
	if (!(oplock_request & INTERNAL_OPEN_ONLY)) {
		smlock_init(conn, &sml, is_executable(path), access_mask,
		    share_access, create_options);
		psml = &sml;
	}

	smlock_dump(10, psml);

	ret_fd = ifs_createfile(base_fd, path,
	    (enum ifs_ace_rights)open_access_mask, flags & ~O_ACCMODE, mode,
	    onefs_oplock, id, psml, secinfo, pifs_sd, onefs_dos_attributes,
	    cf_flags, &onefs_granted_oplock);

	DEBUG(10,("onefs_sys_create_file(%s): ret_fd = %d, "
		  "onefs_granted_oplock = %s\n",
		  ret_fd < 0 ? strerror(errno) : "success", ret_fd,
		  onefs_oplock_str(onefs_granted_oplock)));

	if (granted_oplock) {
		*granted_oplock =
		    onefs_oplock_to_samba_oplock(onefs_granted_oplock);
	}

 out:
	END_PROFILE(syscall_createfile);
	aclu_free_sd(pifs_sd, false);

	return ret_fd;
}

/**
 * FreeBSD based sendfile implementation that allows for atomic semantics.
 */
static ssize_t onefs_sys_do_sendfile(int tofd, int fromfd,
    const DATA_BLOB *header, SMB_OFF_T offset, size_t count, bool atomic)
{
	size_t total=0;
	struct sf_hdtr hdr;
	struct iovec hdtrl;
	size_t hdr_len = 0;
	int flags = 0;

	if (atomic) {
		flags = SF_ATOMIC;
	}

	hdr.headers = &hdtrl;
	hdr.hdr_cnt = 1;
	hdr.trailers = NULL;
	hdr.trl_cnt = 0;

	/* Set up the header iovec. */
	if (header) {
		hdtrl.iov_base = header->data;
		hdtrl.iov_len = hdr_len = header->length;
	} else {
		hdtrl.iov_base = NULL;
		hdtrl.iov_len = 0;
	}

	total = count;
	while (total + hdtrl.iov_len) {
		SMB_OFF_T nwritten;
		int ret;

		/*
		 * FreeBSD sendfile returns 0 on success, -1 on error.
		 * Remember, the tofd and fromfd are reversed..... :-).
		 * nwritten includes the header data sent.
		 */

		do {
			ret = sendfile(fromfd, tofd, offset, total, &hdr,
				       &nwritten, flags);
		} while (ret == -1 && errno == EINTR);

		/* On error we're done. */
		if (ret == -1) {
			return -1;
		}

		/*
		 * If this was an ATOMIC sendfile, nwritten doesn't
		 * necessarily indicate an error.  It could mean count > than
		 * what sendfile can handle atomically (usually 64K) or that
		 * there was a short read due to the file being truncated.
		 */
		if (nwritten == 0) {
			return atomic ? 0 : -1;
		}

		/*
		 * An atomic sendfile should never send partial data!
		 */
		if (atomic && nwritten != total + hdtrl.iov_len) {
			DEBUG(0,("Atomic sendfile() sent partial data: "
				 "%llu of %d\n", nwritten,
				 total + hdtrl.iov_len));
			return -1;
		}

		/*
		 * If this was a short (signal interrupted) write we may need
		 * to subtract it from the header data, or null out the header
		 * data altogether if we wrote more than hdtrl.iov_len bytes.
		 * We change nwritten to be the number of file bytes written.
		 */

		if (hdtrl.iov_base && hdtrl.iov_len) {
			if (nwritten >= hdtrl.iov_len) {
				nwritten -= hdtrl.iov_len;
				hdtrl.iov_base = NULL;
				hdtrl.iov_len = 0;
			} else {
				hdtrl.iov_base =
				    (caddr_t)hdtrl.iov_base + nwritten;
				hdtrl.iov_len -= nwritten;
				nwritten = 0;
			}
		}
		total -= nwritten;
		offset += nwritten;
	}
	return count + hdr_len;
}

/**
 * Handles the subtleties of using sendfile with CIFS.
 */
ssize_t onefs_sys_sendfile(connection_struct *conn, int tofd, int fromfd,
			   const DATA_BLOB *header, SMB_OFF_T offset,
			   size_t count)
{
	bool atomic = false;
	ssize_t ret = 0;

	START_PROFILE_BYTES(syscall_sendfile, count);

	if (lp_parm_bool(SNUM(conn), PARM_ONEFS_TYPE,
			 PARM_ATOMIC_SENDFILE,
			 PARM_ATOMIC_SENDFILE_DEFAULT)) {
		atomic = true;
	}

	/* Try the sendfile */
	ret = onefs_sys_do_sendfile(tofd, fromfd, header, offset, count,
				    atomic);

	/* If the sendfile wasn't atomic, we're done. */
	if (!atomic) {
		DEBUG(10, ("non-atomic sendfile read %ul bytes", ret));
		END_PROFILE(syscall_sendfile);
		return ret;
	}

	/*
	 * Atomic sendfile takes care to not write anything to the socket
	 * until all of the requested bytes have been read from the file.
	 * There are two atomic cases that need to be handled.
	 *
	 *  1. The file was truncated causing less data to be read than was
	 *     requested.  In this case, we return back to the caller to
	 *     indicate 0 bytes were written to the socket.  This should
	 *     prompt the caller to fallback to the standard read path: read
	 *     the data, create a header that indicates how many bytes were
	 *     actually read, and send the header/data back to the client.
	 *
	 *     This saves us from standard sendfile behavior of sending a
	 *     header promising more data then will actually be sent.  The
	 *     only two options are to close the socket and kill the client
	 *     connection, or write a bunch of 0s.  Closing the client
	 *     connection is bad because there could actually be multiple
	 *     sessions multiplexed from the same client that are all dropped
	 *     because of a truncate.  Writing the remaining data as 0s also
	 *     isn't good, because the client will have an incorrect version
	 *     of the file.  If the file is written back to the server, the 0s
	 *     will be written back.  Fortunately, atomic sendfile allows us
	 *     to avoid making this choice in most cases.
	 *
	 *  2. One downside of atomic sendfile, is that there is a limit on
	 *     the number of bytes that can be sent atomically.  The kernel
	 *     has a limited amount of mbuf space that it can read file data
	 *     into without exhausting the system's mbufs, so a buffer of
	 *     length xfsize is used.  The xfsize at the time of writing this
	 *     is 64K.  xfsize bytes are read from the file, and subsequently
	 *     written to the socket.  This makes it impossible to do the
	 *     sendfile atomically for a byte count > xfsize.
	 *
	 *     To cope with large requests, atomic sendfile returns -1 with
	 *     errno set to E2BIG.  Since windows maxes out at 64K writes,
	 *     this is currently only a concern with non-windows clients.
	 *     Posix extensions allow the full 24bit bytecount field to be
	 *     used in ReadAndX, and clients such as smbclient and the linux
	 *     cifs client can request up to 16MB reads!  There are a few
	 *     options for handling large sendfile requests.
	 *
	 *	a. Fall back to the standard read path.  This is unacceptable
	 *         because it would require prohibitively large mallocs.
	 *
	 *	b. Fall back to using samba's fake_send_file which emulates
	 *	   the kernel sendfile in userspace.  This still has the same
	 *	   problem of sending the header before all of the data has
	 *	   been read, so it doesn't buy us anything, and has worse
	 *	   performance than the kernel's zero-copy sendfile.
	 *
	 *	c. Use non-atomic sendfile syscall to attempt a zero copy
	 *	   read, and hope that there isn't a short read due to
	 *	   truncation.  In the case of a short read, there are two
	 *	   options:
	 *
	 *	    1. Kill the client connection
	 *
	 *	    2. Write zeros to the socket for the remaining bytes
	 *	       promised in the header.
	 *
	 *	   It is safer from a data corruption perspective to kill the
	 *	   client connection, so this is our default behavior, but if
	 *	   this causes problems this can be configured to write zeros
	 *	   via smb.conf.
	 */

	/* Handle case 1: short read -> truncated file. */
	if (ret == 0) {
		END_PROFILE(syscall_sendfile);
		return ret;
	}

	/* Handle case 2: large read. */
	if (ret == -1 && errno == E2BIG) {

		if (!lp_parm_bool(SNUM(conn), PARM_ONEFS_TYPE,
				 PARM_SENDFILE_LARGE_READS,
				 PARM_SENDFILE_LARGE_READS_DEFAULT)) {
			DEBUG(3, ("Not attempting non-atomic large sendfile: "
				  "%lu bytes\n", count));
			END_PROFILE(syscall_sendfile);
			return 0;
		}

		if (count < 0x10000) {
			DEBUG(0, ("Count < 2^16 and E2BIG was returned! %lu",
				  count));
		}

		DEBUG(10, ("attempting non-atomic large sendfile: %lu bytes\n",
			   count));

		/* Try a non-atomic sendfile. */
		ret = onefs_sys_do_sendfile(tofd, fromfd, header, offset,
					    count, false);
		/* Real error: kill the client connection. */
		if (ret == -1) {
			DEBUG(1, ("error on non-atomic large sendfile "
				  "(%lu bytes): %s\n", count,
				  strerror(errno)));
			END_PROFILE(syscall_sendfile);
			return ret;
		}

		/* Short read: kill the client connection. */
		if (ret != count + header->length) {
			DEBUG(1, ("short read on non-atomic large sendfile "
				  "(%lu of %lu bytes): %s\n", ret, count,
				  strerror(errno)));

			/*
			 * Returning ret here would cause us to drop into the
			 * codepath that calls sendfile_short_send, which
			 * sends the client a bunch of zeros instead.
			 * Returning -1 kills the connection.
			 */
			if (lp_parm_bool(SNUM(conn), PARM_ONEFS_TYPE,
				PARM_SENDFILE_SAFE,
				PARM_SENDFILE_SAFE_DEFAULT)) {
				END_PROFILE(syscall_sendfile);
				return -1;
			}

			END_PROFILE(syscall_sendfile);
			return ret;
		}

		DEBUG(10, ("non-atomic large sendfile successful\n"));
	}

	/* There was error in the atomic sendfile. */
	if (ret == -1) {
		DEBUG(1, ("error on %s sendfile (%lu bytes): %s\n",
			  atomic ? "atomic" : "non-atomic",
			  count, strerror(errno)));
	}

	END_PROFILE(syscall_sendfile);
	return ret;
}

/**
 * Only talloc the spill buffer once (reallocing when necessary).
 */
static char *get_spill_buffer(size_t new_count)
{
	static int cur_count = 0;
	static char *spill_buffer = NULL;

	/* If a sufficiently sized buffer exists, just return. */
	if (new_count <= cur_count) {
		SMB_ASSERT(spill_buffer);
		return spill_buffer;
	}

	/* Allocate the first time. */
	if (cur_count == 0) {
		SMB_ASSERT(!spill_buffer);
		spill_buffer = talloc_array(NULL, char, new_count);
		if (spill_buffer) {
			cur_count = new_count;
		}
		return spill_buffer;
	}

	/* A buffer exists, but it's not big enough, so realloc. */
	SMB_ASSERT(spill_buffer);
	spill_buffer = talloc_realloc(NULL, spill_buffer, char, new_count);
	if (spill_buffer) {
		cur_count = new_count;
	}
	return spill_buffer;
}

/**
 * recvfile does zero-copy writes given an fd to write to, and a socket with
 * some data to write.  If recvfile read more than it was able to write, it
 * spills the data into a buffer.  After first reading any additional data
 * from the socket into the buffer, the spill buffer is then written with a
 * standard pwrite.
 */
ssize_t onefs_sys_recvfile(int fromfd, int tofd, SMB_OFF_T offset,
			   size_t count)
{
	char *spill_buffer = NULL;
	bool socket_drained = false;
	int ret;
	off_t total_rbytes = 0;
	off_t total_wbytes = 0;
	off_t rbytes;
	off_t wbytes;

	START_PROFILE_BYTES(syscall_recvfile, count);

	DEBUG(10,("onefs_recvfile: from = %d, to = %d, offset=%llu, count = "
		  "%lu\n", fromfd, tofd, offset, count));

	if (count == 0) {
		END_PROFILE(syscall_recvfile);
		return 0;
	}

	/*
	 * Setup up a buffer for recvfile to spill data that has been read
	 * from the socket but not written.
	 */
	spill_buffer = get_spill_buffer(count);
	if (spill_buffer == NULL) {
		ret = -1;
		goto out;
	}

	/*
	 * Keep trying recvfile until:
	 *  - There is no data left to read on the socket, or
	 *  - bytes read != bytes written, or
	 *  - An error is returned that isn't EINTR/EAGAIN
	 */
	do {
		/* Keep track of bytes read/written for recvfile */
		rbytes = 0;
		wbytes = 0;

		DEBUG(10, ("calling recvfile loop, offset + total_wbytes = "
			   "%llu, count - total_rbytes = %llu\n",
			   offset + total_wbytes, count - total_rbytes));

		ret = recvfile(tofd, fromfd, offset + total_wbytes,
			       count - total_wbytes, &rbytes, &wbytes, 0,
			       spill_buffer);

		DEBUG(10, ("recvfile ret = %d, errno = %d, rbytes = %llu, "
			   "wbytes = %llu\n", ret, ret >= 0 ? 0 : errno,
			   rbytes, wbytes));

		/* Update our progress so far */
		total_rbytes += rbytes;
		total_wbytes += wbytes;

	} while ((count - total_rbytes) && (rbytes == wbytes) &&
		 (ret == -1 && (errno == EINTR || errno == EAGAIN)));

	DEBUG(10, ("total_rbytes = %llu, total_wbytes = %llu\n",
		   total_rbytes, total_wbytes));

	/* Log if recvfile didn't write everything it read. */
	if (total_rbytes != total_wbytes) {
		DEBUG(0, ("partial recvfile: total_rbytes=%llu but "
			  "total_wbytes=%llu, diff = %llu\n", total_rbytes,
			  total_wbytes, total_rbytes - total_wbytes));
		SMB_ASSERT(total_rbytes > total_wbytes);
	}

	/*
	 * If there is still data on the socket, read it off.
	 */
	while (total_rbytes < count) {

		DEBUG(0, ("shallow recvfile (%s), reading %llu\n",
			  strerror(errno), count - total_rbytes));

		/*
		 * Read the remaining data into the spill buffer.  recvfile
		 * may already have some data in the spill buffer, so start
		 * filling the buffer at total_rbytes - total_wbytes.
		 */
		ret = sys_read(fromfd,
			       spill_buffer + (total_rbytes - total_wbytes),
			       count - total_rbytes);

		if (ret <= 0) {
			if (ret == 0) {
				DEBUG(0, ("shallow recvfile read: EOF\n"));
			} else {
				DEBUG(0, ("shallow recvfile read failed: %s\n",
					  strerror(errno)));
			}
			/* Socket is dead, so treat as if it were drained. */
			socket_drained = true;
			goto out;
		}

		/* Data was read so update the rbytes */
		total_rbytes += ret;
	}

	if (total_rbytes != count) {
		smb_panic("Unread recvfile data still on the socket!");
	}

	/*
	 * Now write any spilled data + the extra data read off the socket.
	 */
	while (total_wbytes < count) {

		DEBUG(0, ("partial recvfile, writing %llu\n", count - total_wbytes));

		ret = sys_pwrite(tofd, spill_buffer, count - total_wbytes,
				 offset + total_wbytes);

		if (ret == -1) {
			DEBUG(0, ("partial recvfile write failed: %s\n",
				  strerror(errno)));
			goto out;
		}

		/* Data was written so update the wbytes */
		total_wbytes += ret;
	}

	/* Success! */
	ret = total_wbytes;

out:

	END_PROFILE(syscall_recvfile);

	/* Make sure we always try to drain the socket. */
	if (!socket_drained && count - total_rbytes) {
		int saved_errno = errno;

		if (drain_socket(fromfd, count - total_rbytes) !=
		    count - total_rbytes) {
			/* Socket is dead! */
			DEBUG(0, ("drain socket failed: %d\n", errno));
		}
		errno = saved_errno;
	}

	return ret;
}