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1// SPDX-License-Identifier: GPL-2.0-only
2/* Network filesystem write subrequest result collection, assessment
3 * and retrying.
4 *
5 * Copyright (C) 2024 Red Hat, Inc. All Rights Reserved.
6 * Written by David Howells (dhowells@redhat.com)
7 */
8
9#include <linux/export.h>
10#include <linux/fs.h>
11#include <linux/mm.h>
12#include <linux/pagemap.h>
13#include <linux/slab.h>
14#include "internal.h"
15
16/* Notes made in the collector */
17#define HIT_PENDING 0x01 /* A front op was still pending */
18#define NEED_REASSESS 0x02 /* Need to loop round and reassess */
19#define MADE_PROGRESS 0x04 /* Made progress cleaning up a stream or the folio set */
20#define BUFFERED 0x08 /* The pagecache needs cleaning up */
21#define NEED_RETRY 0x10 /* A front op requests retrying */
22#define SAW_FAILURE 0x20 /* One stream or hit a permanent failure */
23
24/*
25 * Successful completion of write of a folio to the server and/or cache. Note
26 * that we are not allowed to lock the folio here on pain of deadlocking with
27 * truncate.
28 */
29int netfs_folio_written_back(struct folio *folio)
30{
31 enum netfs_folio_trace why = netfs_folio_trace_clear;
32 struct netfs_inode *ictx = netfs_inode(folio->mapping->host);
33 struct netfs_folio *finfo;
34 struct netfs_group *group = NULL;
35 int gcount = 0;
36
37 if ((finfo = netfs_folio_info(folio))) {
38 /* Streaming writes cannot be redirtied whilst under writeback,
39 * so discard the streaming record.
40 */
41 unsigned long long fend;
42
43 fend = folio_pos(folio) + finfo->dirty_offset + finfo->dirty_len;
44 if (fend > ictx->zero_point)
45 ictx->zero_point = fend;
46
47 folio_detach_private(folio);
48 group = finfo->netfs_group;
49 gcount++;
50 kfree(finfo);
51 why = netfs_folio_trace_clear_s;
52 goto end_wb;
53 }
54
55 if ((group = netfs_folio_group(folio))) {
56 if (group == NETFS_FOLIO_COPY_TO_CACHE) {
57 why = netfs_folio_trace_clear_cc;
58 folio_detach_private(folio);
59 goto end_wb;
60 }
61
62 /* Need to detach the group pointer if the page didn't get
63 * redirtied. If it has been redirtied, then it must be within
64 * the same group.
65 */
66 why = netfs_folio_trace_redirtied;
67 if (!folio_test_dirty(folio)) {
68 folio_detach_private(folio);
69 gcount++;
70 why = netfs_folio_trace_clear_g;
71 }
72 }
73
74end_wb:
75 trace_netfs_folio(folio, why);
76 folio_end_writeback(folio);
77 return gcount;
78}
79
80/*
81 * Unlock any folios we've finished with.
82 */
83static void netfs_writeback_unlock_folios(struct netfs_io_request *wreq,
84 unsigned int *notes)
85{
86 struct folio_queue *folioq = wreq->buffer;
87 unsigned long long collected_to = wreq->collected_to;
88 unsigned int slot = wreq->buffer_head_slot;
89
90 if (wreq->origin == NETFS_PGPRIV2_COPY_TO_CACHE) {
91 if (netfs_pgpriv2_unlock_copied_folios(wreq))
92 *notes |= MADE_PROGRESS;
93 return;
94 }
95
96 if (slot >= folioq_nr_slots(folioq)) {
97 folioq = netfs_delete_buffer_head(wreq);
98 slot = 0;
99 }
100
101 for (;;) {
102 struct folio *folio;
103 struct netfs_folio *finfo;
104 unsigned long long fpos, fend;
105 size_t fsize, flen;
106
107 folio = folioq_folio(folioq, slot);
108 if (WARN_ONCE(!folio_test_writeback(folio),
109 "R=%08x: folio %lx is not under writeback\n",
110 wreq->debug_id, folio->index))
111 trace_netfs_folio(folio, netfs_folio_trace_not_under_wback);
112
113 fpos = folio_pos(folio);
114 fsize = folio_size(folio);
115 finfo = netfs_folio_info(folio);
116 flen = finfo ? finfo->dirty_offset + finfo->dirty_len : fsize;
117
118 fend = min_t(unsigned long long, fpos + flen, wreq->i_size);
119
120 trace_netfs_collect_folio(wreq, folio, fend, collected_to);
121
122 /* Unlock any folio we've transferred all of. */
123 if (collected_to < fend)
124 break;
125
126 wreq->nr_group_rel += netfs_folio_written_back(folio);
127 wreq->cleaned_to = fpos + fsize;
128 *notes |= MADE_PROGRESS;
129
130 /* Clean up the head folioq. If we clear an entire folioq, then
131 * we can get rid of it provided it's not also the tail folioq
132 * being filled by the issuer.
133 */
134 folioq_clear(folioq, slot);
135 slot++;
136 if (slot >= folioq_nr_slots(folioq)) {
137 if (READ_ONCE(wreq->buffer_tail) == folioq)
138 break;
139 folioq = netfs_delete_buffer_head(wreq);
140 slot = 0;
141 }
142
143 if (fpos + fsize >= collected_to)
144 break;
145 }
146
147 wreq->buffer = folioq;
148 wreq->buffer_head_slot = slot;
149}
150
151/*
152 * Perform retries on the streams that need it.
153 */
154static void netfs_retry_write_stream(struct netfs_io_request *wreq,
155 struct netfs_io_stream *stream)
156{
157 struct list_head *next;
158
159 _enter("R=%x[%x:]", wreq->debug_id, stream->stream_nr);
160
161 if (list_empty(&stream->subrequests))
162 return;
163
164 if (stream->source == NETFS_UPLOAD_TO_SERVER &&
165 wreq->netfs_ops->retry_request)
166 wreq->netfs_ops->retry_request(wreq, stream);
167
168 if (unlikely(stream->failed))
169 return;
170
171 /* If there's no renegotiation to do, just resend each failed subreq. */
172 if (!stream->prepare_write) {
173 struct netfs_io_subrequest *subreq;
174
175 list_for_each_entry(subreq, &stream->subrequests, rreq_link) {
176 if (test_bit(NETFS_SREQ_FAILED, &subreq->flags))
177 break;
178 if (__test_and_clear_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags)) {
179 struct iov_iter source = subreq->io_iter;
180
181 iov_iter_revert(&source, subreq->len - source.count);
182 netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit);
183 netfs_reissue_write(stream, subreq, &source);
184 }
185 }
186 return;
187 }
188
189 next = stream->subrequests.next;
190
191 do {
192 struct netfs_io_subrequest *subreq = NULL, *from, *to, *tmp;
193 struct iov_iter source;
194 unsigned long long start, len;
195 size_t part;
196 bool boundary = false;
197
198 /* Go through the stream and find the next span of contiguous
199 * data that we then rejig (cifs, for example, needs the wsize
200 * renegotiating) and reissue.
201 */
202 from = list_entry(next, struct netfs_io_subrequest, rreq_link);
203 to = from;
204 start = from->start + from->transferred;
205 len = from->len - from->transferred;
206
207 if (test_bit(NETFS_SREQ_FAILED, &from->flags) ||
208 !test_bit(NETFS_SREQ_NEED_RETRY, &from->flags))
209 return;
210
211 list_for_each_continue(next, &stream->subrequests) {
212 subreq = list_entry(next, struct netfs_io_subrequest, rreq_link);
213 if (subreq->start + subreq->transferred != start + len ||
214 test_bit(NETFS_SREQ_BOUNDARY, &subreq->flags) ||
215 !test_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags))
216 break;
217 to = subreq;
218 len += to->len;
219 }
220
221 /* Determine the set of buffers we're going to use. Each
222 * subreq gets a subset of a single overall contiguous buffer.
223 */
224 netfs_reset_iter(from);
225 source = from->io_iter;
226 source.count = len;
227
228 /* Work through the sublist. */
229 subreq = from;
230 list_for_each_entry_from(subreq, &stream->subrequests, rreq_link) {
231 if (!len)
232 break;
233 /* Renegotiate max_len (wsize) */
234 trace_netfs_sreq(subreq, netfs_sreq_trace_retry);
235 __clear_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags);
236 subreq->retry_count++;
237 stream->prepare_write(subreq);
238
239 part = min(len, stream->sreq_max_len);
240 subreq->len = part;
241 subreq->start = start;
242 subreq->transferred = 0;
243 len -= part;
244 start += part;
245 if (len && subreq == to &&
246 __test_and_clear_bit(NETFS_SREQ_BOUNDARY, &to->flags))
247 boundary = true;
248
249 netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit);
250 netfs_reissue_write(stream, subreq, &source);
251 if (subreq == to)
252 break;
253 }
254
255 /* If we managed to use fewer subreqs, we can discard the
256 * excess; if we used the same number, then we're done.
257 */
258 if (!len) {
259 if (subreq == to)
260 continue;
261 list_for_each_entry_safe_from(subreq, tmp,
262 &stream->subrequests, rreq_link) {
263 trace_netfs_sreq(subreq, netfs_sreq_trace_discard);
264 list_del(&subreq->rreq_link);
265 netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_done);
266 if (subreq == to)
267 break;
268 }
269 continue;
270 }
271
272 /* We ran out of subrequests, so we need to allocate some more
273 * and insert them after.
274 */
275 do {
276 subreq = netfs_alloc_subrequest(wreq);
277 subreq->source = to->source;
278 subreq->start = start;
279 subreq->debug_index = atomic_inc_return(&wreq->subreq_counter);
280 subreq->stream_nr = to->stream_nr;
281 subreq->retry_count = 1;
282
283 trace_netfs_sreq_ref(wreq->debug_id, subreq->debug_index,
284 refcount_read(&subreq->ref),
285 netfs_sreq_trace_new);
286 netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit);
287
288 list_add(&subreq->rreq_link, &to->rreq_link);
289 to = list_next_entry(to, rreq_link);
290 trace_netfs_sreq(subreq, netfs_sreq_trace_retry);
291
292 stream->sreq_max_len = len;
293 stream->sreq_max_segs = INT_MAX;
294 switch (stream->source) {
295 case NETFS_UPLOAD_TO_SERVER:
296 netfs_stat(&netfs_n_wh_upload);
297 stream->sreq_max_len = umin(len, wreq->wsize);
298 break;
299 case NETFS_WRITE_TO_CACHE:
300 netfs_stat(&netfs_n_wh_write);
301 break;
302 default:
303 WARN_ON_ONCE(1);
304 }
305
306 stream->prepare_write(subreq);
307
308 part = umin(len, stream->sreq_max_len);
309 subreq->len = subreq->transferred + part;
310 len -= part;
311 start += part;
312 if (!len && boundary) {
313 __set_bit(NETFS_SREQ_BOUNDARY, &to->flags);
314 boundary = false;
315 }
316
317 netfs_reissue_write(stream, subreq, &source);
318 if (!len)
319 break;
320
321 } while (len);
322
323 } while (!list_is_head(next, &stream->subrequests));
324}
325
326/*
327 * Perform retries on the streams that need it. If we're doing content
328 * encryption and the server copy changed due to a third-party write, we may
329 * need to do an RMW cycle and also rewrite the data to the cache.
330 */
331static void netfs_retry_writes(struct netfs_io_request *wreq)
332{
333 struct netfs_io_subrequest *subreq;
334 struct netfs_io_stream *stream;
335 int s;
336
337 /* Wait for all outstanding I/O to quiesce before performing retries as
338 * we may need to renegotiate the I/O sizes.
339 */
340 for (s = 0; s < NR_IO_STREAMS; s++) {
341 stream = &wreq->io_streams[s];
342 if (!stream->active)
343 continue;
344
345 list_for_each_entry(subreq, &stream->subrequests, rreq_link) {
346 wait_on_bit(&subreq->flags, NETFS_SREQ_IN_PROGRESS,
347 TASK_UNINTERRUPTIBLE);
348 }
349 }
350
351 // TODO: Enc: Fetch changed partial pages
352 // TODO: Enc: Reencrypt content if needed.
353 // TODO: Enc: Wind back transferred point.
354 // TODO: Enc: Mark cache pages for retry.
355
356 for (s = 0; s < NR_IO_STREAMS; s++) {
357 stream = &wreq->io_streams[s];
358 if (stream->need_retry) {
359 stream->need_retry = false;
360 netfs_retry_write_stream(wreq, stream);
361 }
362 }
363}
364
365/*
366 * Collect and assess the results of various write subrequests. We may need to
367 * retry some of the results - or even do an RMW cycle for content crypto.
368 *
369 * Note that we have a number of parallel, overlapping lists of subrequests,
370 * one to the server and one to the local cache for example, which may not be
371 * the same size or starting position and may not even correspond in boundary
372 * alignment.
373 */
374static void netfs_collect_write_results(struct netfs_io_request *wreq)
375{
376 struct netfs_io_subrequest *front, *remove;
377 struct netfs_io_stream *stream;
378 unsigned long long collected_to, issued_to;
379 unsigned int notes;
380 int s;
381
382 _enter("%llx-%llx", wreq->start, wreq->start + wreq->len);
383 trace_netfs_collect(wreq);
384 trace_netfs_rreq(wreq, netfs_rreq_trace_collect);
385
386reassess_streams:
387 issued_to = atomic64_read(&wreq->issued_to);
388 smp_rmb();
389 collected_to = ULLONG_MAX;
390 if (wreq->origin == NETFS_WRITEBACK ||
391 wreq->origin == NETFS_WRITETHROUGH ||
392 wreq->origin == NETFS_PGPRIV2_COPY_TO_CACHE)
393 notes = BUFFERED;
394 else
395 notes = 0;
396
397 /* Remove completed subrequests from the front of the streams and
398 * advance the completion point on each stream. We stop when we hit
399 * something that's in progress. The issuer thread may be adding stuff
400 * to the tail whilst we're doing this.
401 */
402 for (s = 0; s < NR_IO_STREAMS; s++) {
403 stream = &wreq->io_streams[s];
404 /* Read active flag before list pointers */
405 if (!smp_load_acquire(&stream->active))
406 continue;
407
408 front = stream->front;
409 while (front) {
410 trace_netfs_collect_sreq(wreq, front);
411 //_debug("sreq [%x] %llx %zx/%zx",
412 // front->debug_index, front->start, front->transferred, front->len);
413
414 if (stream->collected_to < front->start) {
415 trace_netfs_collect_gap(wreq, stream, issued_to, 'F');
416 stream->collected_to = front->start;
417 }
418
419 /* Stall if the front is still undergoing I/O. */
420 if (test_bit(NETFS_SREQ_IN_PROGRESS, &front->flags)) {
421 notes |= HIT_PENDING;
422 break;
423 }
424 smp_rmb(); /* Read counters after I-P flag. */
425
426 if (stream->failed) {
427 stream->collected_to = front->start + front->len;
428 notes |= MADE_PROGRESS | SAW_FAILURE;
429 goto cancel;
430 }
431 if (front->start + front->transferred > stream->collected_to) {
432 stream->collected_to = front->start + front->transferred;
433 stream->transferred = stream->collected_to - wreq->start;
434 notes |= MADE_PROGRESS;
435 }
436 if (test_bit(NETFS_SREQ_FAILED, &front->flags)) {
437 stream->failed = true;
438 stream->error = front->error;
439 if (stream->source == NETFS_UPLOAD_TO_SERVER)
440 mapping_set_error(wreq->mapping, front->error);
441 notes |= NEED_REASSESS | SAW_FAILURE;
442 break;
443 }
444 if (front->transferred < front->len) {
445 stream->need_retry = true;
446 notes |= NEED_RETRY | MADE_PROGRESS;
447 break;
448 }
449
450 cancel:
451 /* Remove if completely consumed. */
452 spin_lock_bh(&wreq->lock);
453
454 remove = front;
455 list_del_init(&front->rreq_link);
456 front = list_first_entry_or_null(&stream->subrequests,
457 struct netfs_io_subrequest, rreq_link);
458 stream->front = front;
459 spin_unlock_bh(&wreq->lock);
460 netfs_put_subrequest(remove, false,
461 notes & SAW_FAILURE ?
462 netfs_sreq_trace_put_cancel :
463 netfs_sreq_trace_put_done);
464 }
465
466 /* If we have an empty stream, we need to jump it forward
467 * otherwise the collection point will never advance.
468 */
469 if (!front && issued_to > stream->collected_to) {
470 trace_netfs_collect_gap(wreq, stream, issued_to, 'E');
471 stream->collected_to = issued_to;
472 }
473
474 if (stream->collected_to < collected_to)
475 collected_to = stream->collected_to;
476 }
477
478 if (collected_to != ULLONG_MAX && collected_to > wreq->collected_to)
479 wreq->collected_to = collected_to;
480
481 for (s = 0; s < NR_IO_STREAMS; s++) {
482 stream = &wreq->io_streams[s];
483 if (stream->active)
484 trace_netfs_collect_stream(wreq, stream);
485 }
486
487 trace_netfs_collect_state(wreq, wreq->collected_to, notes);
488
489 /* Unlock any folios that we have now finished with. */
490 if (notes & BUFFERED) {
491 if (wreq->cleaned_to < wreq->collected_to)
492 netfs_writeback_unlock_folios(wreq, ¬es);
493 } else {
494 wreq->cleaned_to = wreq->collected_to;
495 }
496
497 // TODO: Discard encryption buffers
498
499 if (notes & NEED_RETRY)
500 goto need_retry;
501 if ((notes & MADE_PROGRESS) && test_bit(NETFS_RREQ_PAUSE, &wreq->flags)) {
502 trace_netfs_rreq(wreq, netfs_rreq_trace_unpause);
503 clear_and_wake_up_bit(NETFS_RREQ_PAUSE, &wreq->flags);
504 }
505
506 if (notes & NEED_REASSESS) {
507 //cond_resched();
508 goto reassess_streams;
509 }
510 if (notes & MADE_PROGRESS) {
511 //cond_resched();
512 goto reassess_streams;
513 }
514
515out:
516 netfs_put_group_many(wreq->group, wreq->nr_group_rel);
517 wreq->nr_group_rel = 0;
518 _leave(" = %x", notes);
519 return;
520
521need_retry:
522 /* Okay... We're going to have to retry one or both streams. Note
523 * that any partially completed op will have had any wholly transferred
524 * folios removed from it.
525 */
526 _debug("retry");
527 netfs_retry_writes(wreq);
528 goto out;
529}
530
531/*
532 * Perform the collection of subrequests, folios and encryption buffers.
533 */
534void netfs_write_collection_worker(struct work_struct *work)
535{
536 struct netfs_io_request *wreq = container_of(work, struct netfs_io_request, work);
537 struct netfs_inode *ictx = netfs_inode(wreq->inode);
538 size_t transferred;
539 int s;
540
541 _enter("R=%x", wreq->debug_id);
542
543 netfs_see_request(wreq, netfs_rreq_trace_see_work);
544 if (!test_bit(NETFS_RREQ_IN_PROGRESS, &wreq->flags)) {
545 netfs_put_request(wreq, false, netfs_rreq_trace_put_work);
546 return;
547 }
548
549 netfs_collect_write_results(wreq);
550
551 /* We're done when the app thread has finished posting subreqs and all
552 * the queues in all the streams are empty.
553 */
554 if (!test_bit(NETFS_RREQ_ALL_QUEUED, &wreq->flags)) {
555 netfs_put_request(wreq, false, netfs_rreq_trace_put_work);
556 return;
557 }
558 smp_rmb(); /* Read ALL_QUEUED before lists. */
559
560 transferred = LONG_MAX;
561 for (s = 0; s < NR_IO_STREAMS; s++) {
562 struct netfs_io_stream *stream = &wreq->io_streams[s];
563 if (!stream->active)
564 continue;
565 if (!list_empty(&stream->subrequests)) {
566 netfs_put_request(wreq, false, netfs_rreq_trace_put_work);
567 return;
568 }
569 if (stream->transferred < transferred)
570 transferred = stream->transferred;
571 }
572
573 /* Okay, declare that all I/O is complete. */
574 wreq->transferred = transferred;
575 trace_netfs_rreq(wreq, netfs_rreq_trace_write_done);
576
577 if (wreq->io_streams[1].active &&
578 wreq->io_streams[1].failed) {
579 /* Cache write failure doesn't prevent writeback completion
580 * unless we're in disconnected mode.
581 */
582 ictx->ops->invalidate_cache(wreq);
583 }
584
585 if (wreq->cleanup)
586 wreq->cleanup(wreq);
587
588 if (wreq->origin == NETFS_DIO_WRITE &&
589 wreq->mapping->nrpages) {
590 /* mmap may have got underfoot and we may now have folios
591 * locally covering the region we just wrote. Attempt to
592 * discard the folios, but leave in place any modified locally.
593 * ->write_iter() is prevented from interfering by the DIO
594 * counter.
595 */
596 pgoff_t first = wreq->start >> PAGE_SHIFT;
597 pgoff_t last = (wreq->start + wreq->transferred - 1) >> PAGE_SHIFT;
598 invalidate_inode_pages2_range(wreq->mapping, first, last);
599 }
600
601 if (wreq->origin == NETFS_DIO_WRITE)
602 inode_dio_end(wreq->inode);
603
604 _debug("finished");
605 trace_netfs_rreq(wreq, netfs_rreq_trace_wake_ip);
606 clear_and_wake_up_bit(NETFS_RREQ_IN_PROGRESS, &wreq->flags);
607
608 if (wreq->iocb) {
609 size_t written = min(wreq->transferred, wreq->len);
610 wreq->iocb->ki_pos += written;
611 if (wreq->iocb->ki_complete)
612 wreq->iocb->ki_complete(
613 wreq->iocb, wreq->error ? wreq->error : written);
614 wreq->iocb = VFS_PTR_POISON;
615 }
616
617 netfs_clear_subrequests(wreq, false);
618 netfs_put_request(wreq, false, netfs_rreq_trace_put_work_complete);
619}
620
621/*
622 * Wake the collection work item.
623 */
624void netfs_wake_write_collector(struct netfs_io_request *wreq, bool was_async)
625{
626 if (!work_pending(&wreq->work)) {
627 netfs_get_request(wreq, netfs_rreq_trace_get_work);
628 if (!queue_work(system_unbound_wq, &wreq->work))
629 netfs_put_request(wreq, was_async, netfs_rreq_trace_put_work_nq);
630 }
631}
632
633/**
634 * netfs_write_subrequest_terminated - Note the termination of a write operation.
635 * @_op: The I/O request that has terminated.
636 * @transferred_or_error: The amount of data transferred or an error code.
637 * @was_async: The termination was asynchronous
638 *
639 * This tells the library that a contributory write I/O operation has
640 * terminated, one way or another, and that it should collect the results.
641 *
642 * The caller indicates in @transferred_or_error the outcome of the operation,
643 * supplying a positive value to indicate the number of bytes transferred or a
644 * negative error code. The library will look after reissuing I/O operations
645 * as appropriate and writing downloaded data to the cache.
646 *
647 * If @was_async is true, the caller might be running in softirq or interrupt
648 * context and we can't sleep.
649 *
650 * When this is called, ownership of the subrequest is transferred back to the
651 * library, along with a ref.
652 *
653 * Note that %_op is a void* so that the function can be passed to
654 * kiocb::term_func without the need for a casting wrapper.
655 */
656void netfs_write_subrequest_terminated(void *_op, ssize_t transferred_or_error,
657 bool was_async)
658{
659 struct netfs_io_subrequest *subreq = _op;
660 struct netfs_io_request *wreq = subreq->rreq;
661 struct netfs_io_stream *stream = &wreq->io_streams[subreq->stream_nr];
662
663 _enter("%x[%x] %zd", wreq->debug_id, subreq->debug_index, transferred_or_error);
664
665 switch (subreq->source) {
666 case NETFS_UPLOAD_TO_SERVER:
667 netfs_stat(&netfs_n_wh_upload_done);
668 break;
669 case NETFS_WRITE_TO_CACHE:
670 netfs_stat(&netfs_n_wh_write_done);
671 break;
672 case NETFS_INVALID_WRITE:
673 break;
674 default:
675 BUG();
676 }
677
678 if (IS_ERR_VALUE(transferred_or_error)) {
679 subreq->error = transferred_or_error;
680 if (subreq->error == -EAGAIN)
681 set_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags);
682 else
683 set_bit(NETFS_SREQ_FAILED, &subreq->flags);
684 trace_netfs_failure(wreq, subreq, transferred_or_error, netfs_fail_write);
685
686 switch (subreq->source) {
687 case NETFS_WRITE_TO_CACHE:
688 netfs_stat(&netfs_n_wh_write_failed);
689 break;
690 case NETFS_UPLOAD_TO_SERVER:
691 netfs_stat(&netfs_n_wh_upload_failed);
692 break;
693 default:
694 break;
695 }
696 trace_netfs_rreq(wreq, netfs_rreq_trace_set_pause);
697 set_bit(NETFS_RREQ_PAUSE, &wreq->flags);
698 } else {
699 if (WARN(transferred_or_error > subreq->len - subreq->transferred,
700 "Subreq excess write: R=%x[%x] %zd > %zu - %zu",
701 wreq->debug_id, subreq->debug_index,
702 transferred_or_error, subreq->len, subreq->transferred))
703 transferred_or_error = subreq->len - subreq->transferred;
704
705 subreq->error = 0;
706 subreq->transferred += transferred_or_error;
707
708 if (subreq->transferred < subreq->len)
709 set_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags);
710 }
711
712 trace_netfs_sreq(subreq, netfs_sreq_trace_terminated);
713
714 clear_and_wake_up_bit(NETFS_SREQ_IN_PROGRESS, &subreq->flags);
715
716 /* If we are at the head of the queue, wake up the collector,
717 * transferring a ref to it if we were the ones to do so.
718 */
719 if (list_is_first(&subreq->rreq_link, &stream->subrequests))
720 netfs_wake_write_collector(wreq, was_async);
721
722 netfs_put_subrequest(subreq, was_async, netfs_sreq_trace_put_terminated);
723}
724EXPORT_SYMBOL(netfs_write_subrequest_terminated);