summaryrefslogtreecommitdiffstats
path: root/fs/netfs/write_collect.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/netfs/write_collect.c')
-rw-r--r--fs/netfs/write_collect.c809
1 files changed, 809 insertions, 0 deletions
diff --git a/fs/netfs/write_collect.c b/fs/netfs/write_collect.c
new file mode 100644
index 0000000000..488147439f
--- /dev/null
+++ b/fs/netfs/write_collect.c
@@ -0,0 +1,809 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Network filesystem write subrequest result collection, assessment
+ * and retrying.
+ *
+ * Copyright (C) 2024 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/export.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/slab.h>
+#include "internal.h"
+
+/* Notes made in the collector */
+#define HIT_PENDING 0x01 /* A front op was still pending */
+#define SOME_EMPTY 0x02 /* One of more streams are empty */
+#define ALL_EMPTY 0x04 /* All streams are empty */
+#define MAYBE_DISCONTIG 0x08 /* A front op may be discontiguous (rounded to PAGE_SIZE) */
+#define NEED_REASSESS 0x10 /* Need to loop round and reassess */
+#define REASSESS_DISCONTIG 0x20 /* Reassess discontiguity if contiguity advances */
+#define MADE_PROGRESS 0x40 /* Made progress cleaning up a stream or the folio set */
+#define BUFFERED 0x80 /* The pagecache needs cleaning up */
+#define NEED_RETRY 0x100 /* A front op requests retrying */
+#define SAW_FAILURE 0x200 /* One stream or hit a permanent failure */
+
+/*
+ * Successful completion of write of a folio to the server and/or cache. Note
+ * that we are not allowed to lock the folio here on pain of deadlocking with
+ * truncate.
+ */
+int netfs_folio_written_back(struct folio *folio)
+{
+ enum netfs_folio_trace why = netfs_folio_trace_clear;
+ struct netfs_folio *finfo;
+ struct netfs_group *group = NULL;
+ int gcount = 0;
+
+ if ((finfo = netfs_folio_info(folio))) {
+ /* Streaming writes cannot be redirtied whilst under writeback,
+ * so discard the streaming record.
+ */
+ folio_detach_private(folio);
+ group = finfo->netfs_group;
+ gcount++;
+ kfree(finfo);
+ why = netfs_folio_trace_clear_s;
+ goto end_wb;
+ }
+
+ if ((group = netfs_folio_group(folio))) {
+ if (group == NETFS_FOLIO_COPY_TO_CACHE) {
+ why = netfs_folio_trace_clear_cc;
+ folio_detach_private(folio);
+ goto end_wb;
+ }
+
+ /* Need to detach the group pointer if the page didn't get
+ * redirtied. If it has been redirtied, then it must be within
+ * the same group.
+ */
+ why = netfs_folio_trace_redirtied;
+ if (!folio_test_dirty(folio)) {
+ folio_detach_private(folio);
+ gcount++;
+ why = netfs_folio_trace_clear_g;
+ }
+ }
+
+end_wb:
+ trace_netfs_folio(folio, why);
+ folio_end_writeback(folio);
+ return gcount;
+}
+
+/*
+ * Get hold of a folio we have under writeback. We don't want to get the
+ * refcount on it.
+ */
+static struct folio *netfs_writeback_lookup_folio(struct netfs_io_request *wreq, loff_t pos)
+{
+ XA_STATE(xas, &wreq->mapping->i_pages, pos / PAGE_SIZE);
+ struct folio *folio;
+
+ rcu_read_lock();
+
+ for (;;) {
+ xas_reset(&xas);
+ folio = xas_load(&xas);
+ if (xas_retry(&xas, folio))
+ continue;
+
+ if (!folio || xa_is_value(folio))
+ kdebug("R=%08x: folio %lx (%llx) not present",
+ wreq->debug_id, xas.xa_index, pos / PAGE_SIZE);
+ BUG_ON(!folio || xa_is_value(folio));
+
+ if (folio == xas_reload(&xas))
+ break;
+ }
+
+ rcu_read_unlock();
+
+ if (WARN_ONCE(!folio_test_writeback(folio),
+ "R=%08x: folio %lx is not under writeback\n",
+ wreq->debug_id, folio->index)) {
+ trace_netfs_folio(folio, netfs_folio_trace_not_under_wback);
+ }
+ return folio;
+}
+
+/*
+ * Unlock any folios we've finished with.
+ */
+static void netfs_writeback_unlock_folios(struct netfs_io_request *wreq,
+ unsigned long long collected_to,
+ unsigned int *notes)
+{
+ for (;;) {
+ struct folio *folio;
+ struct netfs_folio *finfo;
+ unsigned long long fpos, fend;
+ size_t fsize, flen;
+
+ folio = netfs_writeback_lookup_folio(wreq, wreq->cleaned_to);
+
+ fpos = folio_pos(folio);
+ fsize = folio_size(folio);
+ finfo = netfs_folio_info(folio);
+ flen = finfo ? finfo->dirty_offset + finfo->dirty_len : fsize;
+
+ fend = min_t(unsigned long long, fpos + flen, wreq->i_size);
+
+ trace_netfs_collect_folio(wreq, folio, fend, collected_to);
+
+ if (fpos + fsize > wreq->contiguity) {
+ trace_netfs_collect_contig(wreq, fpos + fsize,
+ netfs_contig_trace_unlock);
+ wreq->contiguity = fpos + fsize;
+ }
+
+ /* Unlock any folio we've transferred all of. */
+ if (collected_to < fend)
+ break;
+
+ wreq->nr_group_rel += netfs_folio_written_back(folio);
+ wreq->cleaned_to = fpos + fsize;
+ *notes |= MADE_PROGRESS;
+
+ if (fpos + fsize >= collected_to)
+ break;
+ }
+}
+
+/*
+ * Perform retries on the streams that need it.
+ */
+static void netfs_retry_write_stream(struct netfs_io_request *wreq,
+ struct netfs_io_stream *stream)
+{
+ struct list_head *next;
+
+ kenter("R=%x[%x:]", wreq->debug_id, stream->stream_nr);
+
+ if (list_empty(&stream->subrequests))
+ return;
+
+ if (stream->source == NETFS_UPLOAD_TO_SERVER &&
+ wreq->netfs_ops->retry_request)
+ wreq->netfs_ops->retry_request(wreq, stream);
+
+ if (unlikely(stream->failed))
+ return;
+
+ /* If there's no renegotiation to do, just resend each failed subreq. */
+ if (!stream->prepare_write) {
+ struct netfs_io_subrequest *subreq;
+
+ list_for_each_entry(subreq, &stream->subrequests, rreq_link) {
+ if (test_bit(NETFS_SREQ_FAILED, &subreq->flags))
+ break;
+ if (__test_and_clear_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags)) {
+ __set_bit(NETFS_SREQ_RETRYING, &subreq->flags);
+ netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit);
+ netfs_reissue_write(stream, subreq);
+ }
+ }
+ return;
+ }
+
+ next = stream->subrequests.next;
+
+ do {
+ struct netfs_io_subrequest *subreq = NULL, *from, *to, *tmp;
+ unsigned long long start, len;
+ size_t part;
+ bool boundary = false;
+
+ /* Go through the stream and find the next span of contiguous
+ * data that we then rejig (cifs, for example, needs the wsize
+ * renegotiating) and reissue.
+ */
+ from = list_entry(next, struct netfs_io_subrequest, rreq_link);
+ to = from;
+ start = from->start + from->transferred;
+ len = from->len - from->transferred;
+
+ if (test_bit(NETFS_SREQ_FAILED, &from->flags) ||
+ !test_bit(NETFS_SREQ_NEED_RETRY, &from->flags))
+ return;
+
+ list_for_each_continue(next, &stream->subrequests) {
+ subreq = list_entry(next, struct netfs_io_subrequest, rreq_link);
+ if (subreq->start + subreq->transferred != start + len ||
+ test_bit(NETFS_SREQ_BOUNDARY, &subreq->flags) ||
+ !test_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags))
+ break;
+ to = subreq;
+ len += to->len;
+ }
+
+ /* Work through the sublist. */
+ subreq = from;
+ list_for_each_entry_from(subreq, &stream->subrequests, rreq_link) {
+ if (!len)
+ break;
+ /* Renegotiate max_len (wsize) */
+ trace_netfs_sreq(subreq, netfs_sreq_trace_retry);
+ __clear_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags);
+ __set_bit(NETFS_SREQ_RETRYING, &subreq->flags);
+ stream->prepare_write(subreq);
+
+ part = min(len, subreq->max_len);
+ subreq->len = part;
+ subreq->start = start;
+ subreq->transferred = 0;
+ len -= part;
+ start += part;
+ if (len && subreq == to &&
+ __test_and_clear_bit(NETFS_SREQ_BOUNDARY, &to->flags))
+ boundary = true;
+
+ netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit);
+ netfs_reissue_write(stream, subreq);
+ if (subreq == to)
+ break;
+ }
+
+ /* If we managed to use fewer subreqs, we can discard the
+ * excess; if we used the same number, then we're done.
+ */
+ if (!len) {
+ if (subreq == to)
+ continue;
+ list_for_each_entry_safe_from(subreq, tmp,
+ &stream->subrequests, rreq_link) {
+ trace_netfs_sreq(subreq, netfs_sreq_trace_discard);
+ list_del(&subreq->rreq_link);
+ netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_done);
+ if (subreq == to)
+ break;
+ }
+ continue;
+ }
+
+ /* We ran out of subrequests, so we need to allocate some more
+ * and insert them after.
+ */
+ do {
+ subreq = netfs_alloc_subrequest(wreq);
+ subreq->source = to->source;
+ subreq->start = start;
+ subreq->max_len = len;
+ subreq->max_nr_segs = INT_MAX;
+ subreq->debug_index = atomic_inc_return(&wreq->subreq_counter);
+ subreq->stream_nr = to->stream_nr;
+ __set_bit(NETFS_SREQ_RETRYING, &subreq->flags);
+
+ trace_netfs_sreq_ref(wreq->debug_id, subreq->debug_index,
+ refcount_read(&subreq->ref),
+ netfs_sreq_trace_new);
+ netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit);
+
+ list_add(&subreq->rreq_link, &to->rreq_link);
+ to = list_next_entry(to, rreq_link);
+ trace_netfs_sreq(subreq, netfs_sreq_trace_retry);
+
+ switch (stream->source) {
+ case NETFS_UPLOAD_TO_SERVER:
+ netfs_stat(&netfs_n_wh_upload);
+ subreq->max_len = min(len, wreq->wsize);
+ break;
+ case NETFS_WRITE_TO_CACHE:
+ netfs_stat(&netfs_n_wh_write);
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ }
+
+ stream->prepare_write(subreq);
+
+ part = min(len, subreq->max_len);
+ subreq->len = subreq->transferred + part;
+ len -= part;
+ start += part;
+ if (!len && boundary) {
+ __set_bit(NETFS_SREQ_BOUNDARY, &to->flags);
+ boundary = false;
+ }
+
+ netfs_reissue_write(stream, subreq);
+ if (!len)
+ break;
+
+ } while (len);
+
+ } while (!list_is_head(next, &stream->subrequests));
+}
+
+/*
+ * Perform retries on the streams that need it. If we're doing content
+ * encryption and the server copy changed due to a third-party write, we may
+ * need to do an RMW cycle and also rewrite the data to the cache.
+ */
+static void netfs_retry_writes(struct netfs_io_request *wreq)
+{
+ struct netfs_io_subrequest *subreq;
+ struct netfs_io_stream *stream;
+ int s;
+
+ /* Wait for all outstanding I/O to quiesce before performing retries as
+ * we may need to renegotiate the I/O sizes.
+ */
+ for (s = 0; s < NR_IO_STREAMS; s++) {
+ stream = &wreq->io_streams[s];
+ if (!stream->active)
+ continue;
+
+ list_for_each_entry(subreq, &stream->subrequests, rreq_link) {
+ wait_on_bit(&subreq->flags, NETFS_SREQ_IN_PROGRESS,
+ TASK_UNINTERRUPTIBLE);
+ }
+ }
+
+ // TODO: Enc: Fetch changed partial pages
+ // TODO: Enc: Reencrypt content if needed.
+ // TODO: Enc: Wind back transferred point.
+ // TODO: Enc: Mark cache pages for retry.
+
+ for (s = 0; s < NR_IO_STREAMS; s++) {
+ stream = &wreq->io_streams[s];
+ if (stream->need_retry) {
+ stream->need_retry = false;
+ netfs_retry_write_stream(wreq, stream);
+ }
+ }
+}
+
+/*
+ * Collect and assess the results of various write subrequests. We may need to
+ * retry some of the results - or even do an RMW cycle for content crypto.
+ *
+ * Note that we have a number of parallel, overlapping lists of subrequests,
+ * one to the server and one to the local cache for example, which may not be
+ * the same size or starting position and may not even correspond in boundary
+ * alignment.
+ */
+static void netfs_collect_write_results(struct netfs_io_request *wreq)
+{
+ struct netfs_io_subrequest *front, *remove;
+ struct netfs_io_stream *stream;
+ unsigned long long collected_to;
+ unsigned int notes;
+ int s;
+
+ kenter("%llx-%llx", wreq->start, wreq->start + wreq->len);
+ trace_netfs_collect(wreq);
+ trace_netfs_rreq(wreq, netfs_rreq_trace_collect);
+
+reassess_streams:
+ smp_rmb();
+ collected_to = ULLONG_MAX;
+ if (wreq->origin == NETFS_WRITEBACK)
+ notes = ALL_EMPTY | BUFFERED | MAYBE_DISCONTIG;
+ else if (wreq->origin == NETFS_WRITETHROUGH)
+ notes = ALL_EMPTY | BUFFERED;
+ else
+ notes = ALL_EMPTY;
+
+ /* Remove completed subrequests from the front of the streams and
+ * advance the completion point on each stream. We stop when we hit
+ * something that's in progress. The issuer thread may be adding stuff
+ * to the tail whilst we're doing this.
+ *
+ * We must not, however, merge in discontiguities that span whole
+ * folios that aren't under writeback. This is made more complicated
+ * by the folios in the gap being of unpredictable sizes - if they even
+ * exist - but we don't want to look them up.
+ */
+ for (s = 0; s < NR_IO_STREAMS; s++) {
+ loff_t rstart, rend;
+
+ stream = &wreq->io_streams[s];
+ /* Read active flag before list pointers */
+ if (!smp_load_acquire(&stream->active))
+ continue;
+
+ front = stream->front;
+ while (front) {
+ trace_netfs_collect_sreq(wreq, front);
+ //kdebug("sreq [%x] %llx %zx/%zx",
+ // front->debug_index, front->start, front->transferred, front->len);
+
+ /* Stall if there may be a discontinuity. */
+ rstart = round_down(front->start, PAGE_SIZE);
+ if (rstart > wreq->contiguity) {
+ if (wreq->contiguity > stream->collected_to) {
+ trace_netfs_collect_gap(wreq, stream,
+ wreq->contiguity, 'D');
+ stream->collected_to = wreq->contiguity;
+ }
+ notes |= REASSESS_DISCONTIG;
+ break;
+ }
+ rend = round_up(front->start + front->len, PAGE_SIZE);
+ if (rend > wreq->contiguity) {
+ trace_netfs_collect_contig(wreq, rend,
+ netfs_contig_trace_collect);
+ wreq->contiguity = rend;
+ if (notes & REASSESS_DISCONTIG)
+ notes |= NEED_REASSESS;
+ }
+ notes &= ~MAYBE_DISCONTIG;
+
+ /* Stall if the front is still undergoing I/O. */
+ if (test_bit(NETFS_SREQ_IN_PROGRESS, &front->flags)) {
+ notes |= HIT_PENDING;
+ break;
+ }
+ smp_rmb(); /* Read counters after I-P flag. */
+
+ if (stream->failed) {
+ stream->collected_to = front->start + front->len;
+ notes |= MADE_PROGRESS | SAW_FAILURE;
+ goto cancel;
+ }
+ if (front->start + front->transferred > stream->collected_to) {
+ stream->collected_to = front->start + front->transferred;
+ stream->transferred = stream->collected_to - wreq->start;
+ notes |= MADE_PROGRESS;
+ }
+ if (test_bit(NETFS_SREQ_FAILED, &front->flags)) {
+ stream->failed = true;
+ stream->error = front->error;
+ if (stream->source == NETFS_UPLOAD_TO_SERVER)
+ mapping_set_error(wreq->mapping, front->error);
+ notes |= NEED_REASSESS | SAW_FAILURE;
+ break;
+ }
+ if (front->transferred < front->len) {
+ stream->need_retry = true;
+ notes |= NEED_RETRY | MADE_PROGRESS;
+ break;
+ }
+
+ cancel:
+ /* Remove if completely consumed. */
+ spin_lock(&wreq->lock);
+
+ remove = front;
+ list_del_init(&front->rreq_link);
+ front = list_first_entry_or_null(&stream->subrequests,
+ struct netfs_io_subrequest, rreq_link);
+ stream->front = front;
+ if (!front) {
+ unsigned long long jump_to = atomic64_read(&wreq->issued_to);
+
+ if (stream->collected_to < jump_to) {
+ trace_netfs_collect_gap(wreq, stream, jump_to, 'A');
+ stream->collected_to = jump_to;
+ }
+ }
+
+ spin_unlock(&wreq->lock);
+ netfs_put_subrequest(remove, false,
+ notes & SAW_FAILURE ?
+ netfs_sreq_trace_put_cancel :
+ netfs_sreq_trace_put_done);
+ }
+
+ if (front)
+ notes &= ~ALL_EMPTY;
+ else
+ notes |= SOME_EMPTY;
+
+ if (stream->collected_to < collected_to)
+ collected_to = stream->collected_to;
+ }
+
+ if (collected_to != ULLONG_MAX && collected_to > wreq->collected_to)
+ wreq->collected_to = collected_to;
+
+ /* If we have an empty stream, we need to jump it forward over any gap
+ * otherwise the collection point will never advance.
+ *
+ * Note that the issuer always adds to the stream with the lowest
+ * so-far submitted start, so if we see two consecutive subreqs in one
+ * stream with nothing between then in another stream, then the second
+ * stream has a gap that can be jumped.
+ */
+ if (notes & SOME_EMPTY) {
+ unsigned long long jump_to = wreq->start + READ_ONCE(wreq->submitted);
+
+ for (s = 0; s < NR_IO_STREAMS; s++) {
+ stream = &wreq->io_streams[s];
+ if (stream->active &&
+ stream->front &&
+ stream->front->start < jump_to)
+ jump_to = stream->front->start;
+ }
+
+ for (s = 0; s < NR_IO_STREAMS; s++) {
+ stream = &wreq->io_streams[s];
+ if (stream->active &&
+ !stream->front &&
+ stream->collected_to < jump_to) {
+ trace_netfs_collect_gap(wreq, stream, jump_to, 'B');
+ stream->collected_to = jump_to;
+ }
+ }
+ }
+
+ for (s = 0; s < NR_IO_STREAMS; s++) {
+ stream = &wreq->io_streams[s];
+ if (stream->active)
+ trace_netfs_collect_stream(wreq, stream);
+ }
+
+ trace_netfs_collect_state(wreq, wreq->collected_to, notes);
+
+ /* Unlock any folios that we have now finished with. */
+ if (notes & BUFFERED) {
+ unsigned long long clean_to = min(wreq->collected_to, wreq->contiguity);
+
+ if (wreq->cleaned_to < clean_to)
+ netfs_writeback_unlock_folios(wreq, clean_to, &notes);
+ } else {
+ wreq->cleaned_to = wreq->collected_to;
+ }
+
+ // TODO: Discard encryption buffers
+
+ /* If all streams are discontiguous with the last folio we cleared, we
+ * may need to skip a set of folios.
+ */
+ if ((notes & (MAYBE_DISCONTIG | ALL_EMPTY)) == MAYBE_DISCONTIG) {
+ unsigned long long jump_to = ULLONG_MAX;
+
+ for (s = 0; s < NR_IO_STREAMS; s++) {
+ stream = &wreq->io_streams[s];
+ if (stream->active && stream->front &&
+ stream->front->start < jump_to)
+ jump_to = stream->front->start;
+ }
+
+ trace_netfs_collect_contig(wreq, jump_to, netfs_contig_trace_jump);
+ wreq->contiguity = jump_to;
+ wreq->cleaned_to = jump_to;
+ wreq->collected_to = jump_to;
+ for (s = 0; s < NR_IO_STREAMS; s++) {
+ stream = &wreq->io_streams[s];
+ if (stream->collected_to < jump_to)
+ stream->collected_to = jump_to;
+ }
+ //cond_resched();
+ notes |= MADE_PROGRESS;
+ goto reassess_streams;
+ }
+
+ if (notes & NEED_RETRY)
+ goto need_retry;
+ if ((notes & MADE_PROGRESS) && test_bit(NETFS_RREQ_PAUSE, &wreq->flags)) {
+ trace_netfs_rreq(wreq, netfs_rreq_trace_unpause);
+ clear_bit_unlock(NETFS_RREQ_PAUSE, &wreq->flags);
+ wake_up_bit(&wreq->flags, NETFS_RREQ_PAUSE);
+ }
+
+ if (notes & NEED_REASSESS) {
+ //cond_resched();
+ goto reassess_streams;
+ }
+ if (notes & MADE_PROGRESS) {
+ //cond_resched();
+ goto reassess_streams;
+ }
+
+out:
+ netfs_put_group_many(wreq->group, wreq->nr_group_rel);
+ wreq->nr_group_rel = 0;
+ kleave(" = %x", notes);
+ return;
+
+need_retry:
+ /* Okay... We're going to have to retry one or both streams. Note
+ * that any partially completed op will have had any wholly transferred
+ * folios removed from it.
+ */
+ kdebug("retry");
+ netfs_retry_writes(wreq);
+ goto out;
+}
+
+/*
+ * Perform the collection of subrequests, folios and encryption buffers.
+ */
+void netfs_write_collection_worker(struct work_struct *work)
+{
+ struct netfs_io_request *wreq = container_of(work, struct netfs_io_request, work);
+ struct netfs_inode *ictx = netfs_inode(wreq->inode);
+ size_t transferred;
+ int s;
+
+ kenter("R=%x", wreq->debug_id);
+
+ netfs_see_request(wreq, netfs_rreq_trace_see_work);
+ if (!test_bit(NETFS_RREQ_IN_PROGRESS, &wreq->flags)) {
+ netfs_put_request(wreq, false, netfs_rreq_trace_put_work);
+ return;
+ }
+
+ netfs_collect_write_results(wreq);
+
+ /* We're done when the app thread has finished posting subreqs and all
+ * the queues in all the streams are empty.
+ */
+ if (!test_bit(NETFS_RREQ_ALL_QUEUED, &wreq->flags)) {
+ netfs_put_request(wreq, false, netfs_rreq_trace_put_work);
+ return;
+ }
+ smp_rmb(); /* Read ALL_QUEUED before lists. */
+
+ transferred = LONG_MAX;
+ for (s = 0; s < NR_IO_STREAMS; s++) {
+ struct netfs_io_stream *stream = &wreq->io_streams[s];
+ if (!stream->active)
+ continue;
+ if (!list_empty(&stream->subrequests)) {
+ netfs_put_request(wreq, false, netfs_rreq_trace_put_work);
+ return;
+ }
+ if (stream->transferred < transferred)
+ transferred = stream->transferred;
+ }
+
+ /* Okay, declare that all I/O is complete. */
+ wreq->transferred = transferred;
+ trace_netfs_rreq(wreq, netfs_rreq_trace_write_done);
+
+ if (wreq->io_streams[1].active &&
+ wreq->io_streams[1].failed) {
+ /* Cache write failure doesn't prevent writeback completion
+ * unless we're in disconnected mode.
+ */
+ ictx->ops->invalidate_cache(wreq);
+ }
+
+ if (wreq->cleanup)
+ wreq->cleanup(wreq);
+
+ if (wreq->origin == NETFS_DIO_WRITE &&
+ wreq->mapping->nrpages) {
+ /* mmap may have got underfoot and we may now have folios
+ * locally covering the region we just wrote. Attempt to
+ * discard the folios, but leave in place any modified locally.
+ * ->write_iter() is prevented from interfering by the DIO
+ * counter.
+ */
+ pgoff_t first = wreq->start >> PAGE_SHIFT;
+ pgoff_t last = (wreq->start + wreq->transferred - 1) >> PAGE_SHIFT;
+ invalidate_inode_pages2_range(wreq->mapping, first, last);
+ }
+
+ if (wreq->origin == NETFS_DIO_WRITE)
+ inode_dio_end(wreq->inode);
+
+ kdebug("finished");
+ trace_netfs_rreq(wreq, netfs_rreq_trace_wake_ip);
+ clear_bit_unlock(NETFS_RREQ_IN_PROGRESS, &wreq->flags);
+ wake_up_bit(&wreq->flags, NETFS_RREQ_IN_PROGRESS);
+
+ if (wreq->iocb) {
+ size_t written = min(wreq->transferred, wreq->len);
+ wreq->iocb->ki_pos += written;
+ if (wreq->iocb->ki_complete)
+ wreq->iocb->ki_complete(
+ wreq->iocb, wreq->error ? wreq->error : written);
+ wreq->iocb = VFS_PTR_POISON;
+ }
+
+ netfs_clear_subrequests(wreq, false);
+ netfs_put_request(wreq, false, netfs_rreq_trace_put_work_complete);
+}
+
+/*
+ * Wake the collection work item.
+ */
+void netfs_wake_write_collector(struct netfs_io_request *wreq, bool was_async)
+{
+ if (!work_pending(&wreq->work)) {
+ netfs_get_request(wreq, netfs_rreq_trace_get_work);
+ if (!queue_work(system_unbound_wq, &wreq->work))
+ netfs_put_request(wreq, was_async, netfs_rreq_trace_put_work_nq);
+ }
+}
+
+/**
+ * netfs_write_subrequest_terminated - Note the termination of a write operation.
+ * @_op: The I/O request that has terminated.
+ * @transferred_or_error: The amount of data transferred or an error code.
+ * @was_async: The termination was asynchronous
+ *
+ * This tells the library that a contributory write I/O operation has
+ * terminated, one way or another, and that it should collect the results.
+ *
+ * The caller indicates in @transferred_or_error the outcome of the operation,
+ * supplying a positive value to indicate the number of bytes transferred or a
+ * negative error code. The library will look after reissuing I/O operations
+ * as appropriate and writing downloaded data to the cache.
+ *
+ * If @was_async is true, the caller might be running in softirq or interrupt
+ * context and we can't sleep.
+ *
+ * When this is called, ownership of the subrequest is transferred back to the
+ * library, along with a ref.
+ *
+ * Note that %_op is a void* so that the function can be passed to
+ * kiocb::term_func without the need for a casting wrapper.
+ */
+void netfs_write_subrequest_terminated(void *_op, ssize_t transferred_or_error,
+ bool was_async)
+{
+ struct netfs_io_subrequest *subreq = _op;
+ struct netfs_io_request *wreq = subreq->rreq;
+ struct netfs_io_stream *stream = &wreq->io_streams[subreq->stream_nr];
+
+ kenter("%x[%x] %zd", wreq->debug_id, subreq->debug_index, transferred_or_error);
+
+ switch (subreq->source) {
+ case NETFS_UPLOAD_TO_SERVER:
+ netfs_stat(&netfs_n_wh_upload_done);
+ break;
+ case NETFS_WRITE_TO_CACHE:
+ netfs_stat(&netfs_n_wh_write_done);
+ break;
+ case NETFS_INVALID_WRITE:
+ break;
+ default:
+ BUG();
+ }
+
+ if (IS_ERR_VALUE(transferred_or_error)) {
+ subreq->error = transferred_or_error;
+ if (subreq->error == -EAGAIN)
+ set_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags);
+ else
+ set_bit(NETFS_SREQ_FAILED, &subreq->flags);
+ trace_netfs_failure(wreq, subreq, transferred_or_error, netfs_fail_write);
+
+ switch (subreq->source) {
+ case NETFS_WRITE_TO_CACHE:
+ netfs_stat(&netfs_n_wh_write_failed);
+ break;
+ case NETFS_UPLOAD_TO_SERVER:
+ netfs_stat(&netfs_n_wh_upload_failed);
+ break;
+ default:
+ break;
+ }
+ trace_netfs_rreq(wreq, netfs_rreq_trace_set_pause);
+ set_bit(NETFS_RREQ_PAUSE, &wreq->flags);
+ } else {
+ if (WARN(transferred_or_error > subreq->len - subreq->transferred,
+ "Subreq excess write: R=%x[%x] %zd > %zu - %zu",
+ wreq->debug_id, subreq->debug_index,
+ transferred_or_error, subreq->len, subreq->transferred))
+ transferred_or_error = subreq->len - subreq->transferred;
+
+ subreq->error = 0;
+ subreq->transferred += transferred_or_error;
+
+ if (subreq->transferred < subreq->len)
+ set_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags);
+ }
+
+ trace_netfs_sreq(subreq, netfs_sreq_trace_terminated);
+
+ clear_bit_unlock(NETFS_SREQ_IN_PROGRESS, &subreq->flags);
+ wake_up_bit(&subreq->flags, NETFS_SREQ_IN_PROGRESS);
+
+ /* If we are at the head of the queue, wake up the collector,
+ * transferring a ref to it if we were the ones to do so.
+ */
+ if (list_is_first(&subreq->rreq_link, &stream->subrequests))
+ netfs_wake_write_collector(wreq, was_async);
+
+ netfs_put_subrequest(subreq, was_async, netfs_sreq_trace_put_terminated);
+}
+EXPORT_SYMBOL(netfs_write_subrequest_terminated);