4 files changed, 45 insertions, 171 deletions

diff --git a/fs/netfs/write_collect.c b/fs/netfs/write_collect.c
index 2a47af45faa0..4280dc6ec035 100644
--- a/fs/netfs/write_collect.c
+++ b/fs/netfs/write_collect.c
@@ -15,15 +15,11 @@
 
 /* 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 */
+#define NEED_REASSESS		0x02	/* Need to loop round and reassess */
+#define MADE_PROGRESS		0x04	/* Made progress cleaning up a stream or the folio set */
+#define BUFFERED		0x08	/* The pagecache needs cleaning up */
+#define NEED_RETRY		0x10	/* A front op requests retrying */
+#define SAW_FAILURE		0x20	/* One stream or hit a permanent failure */
 
 /*
  * Successful completion of write of a folio to the server and/or cache.  Note
@@ -85,10 +81,10 @@ end_wb:
  * 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)
 {
 	struct folio_queue *folioq = wreq->buffer;
+	unsigned long long collected_to = wreq->collected_to;
 	unsigned int slot = wreq->buffer_head_slot;
 
 	if (slot >= folioq_nr_slots(folioq)) {
@@ -117,12 +113,6 @@ static void netfs_writeback_unlock_folios(struct netfs_io_request *wreq,
 
 		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;
@@ -380,7 +370,7 @@ 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 long long collected_to, issued_to;
 	unsigned int notes;
 	int s;
 
@@ -389,28 +379,21 @@ static void netfs_collect_write_results(struct netfs_io_request *wreq)
 	trace_netfs_rreq(wreq, netfs_rreq_trace_collect);
 
 reassess_streams:
+	issued_to = atomic64_read(&wreq->issued_to);
 	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;
+	if (wreq->origin == NETFS_WRITEBACK ||
+	    wreq->origin == NETFS_WRITETHROUGH)
+		notes = BUFFERED;
 	else
-		notes = ALL_EMPTY;
+		notes = 0;
 
 	/* 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))
@@ -422,26 +405,10 @@ reassess_streams:
 			//_debug("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;
+			if (stream->collected_to < front->start) {
+				trace_netfs_collect_gap(wreq, stream, issued_to, 'F');
+				stream->collected_to = front->start;
 			}
-			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)) {
@@ -483,15 +450,6 @@ reassess_streams:
 			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_bh(&wreq->lock);
 			netfs_put_subrequest(remove, false,
 					     notes & SAW_FAILURE ?
@@ -499,10 +457,13 @@ reassess_streams:
 					     netfs_sreq_trace_put_done);
 		}
 
-		if (front)
-			notes &= ~ALL_EMPTY;
-		else
-			notes |= SOME_EMPTY;
+		/* If we have an empty stream, we need to jump it forward
+		 * otherwise the collection point will never advance.
+		 */
+		if (!front && issued_to > stream->collected_to) {
+			trace_netfs_collect_gap(wreq, stream, issued_to, 'E');
+			stream->collected_to = issued_to;
+		}
 
 		if (stream->collected_to < collected_to)
 			collected_to = stream->collected_to;
@@ -511,36 +472,6 @@ reassess_streams:
 	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)
@@ -551,43 +482,14 @@ reassess_streams:
 
 	/* 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);
+		if (wreq->cleaned_to < wreq->collected_to)
+			netfs_writeback_unlock_folios(wreq, &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)) {
diff --git a/fs/netfs/write_issue.c b/fs/netfs/write_issue.c
index 9ead075962f0..25fb7e166cc0 100644
--- a/fs/netfs/write_issue.c
+++ b/fs/netfs/write_issue.c
@@ -107,7 +107,6 @@ struct netfs_io_request *netfs_create_write_req(struct address_space *mapping,
 	if (is_buffered && netfs_is_cache_enabled(ictx))
 		fscache_begin_write_operation(&wreq->cache_resources, netfs_i_cookie(ictx));
 
-	wreq->contiguity = wreq->start;
 	wreq->cleaned_to = wreq->start;
 
 	wreq->io_streams[0].stream_nr		= 0;
@@ -158,6 +157,7 @@ static void netfs_prepare_write(struct netfs_io_request *wreq,
 	subreq->source		= stream->source;
 	subreq->start		= start;
 	subreq->stream_nr	= stream->stream_nr;
+	subreq->io_iter		= wreq->io_iter;
 
 	_enter("R=%x[%x]", wreq->debug_id, subreq->debug_index);
 
@@ -213,22 +213,15 @@ static void netfs_prepare_write(struct netfs_io_request *wreq,
  * netfs_write_subrequest_terminated() when complete.
  */
 static void netfs_do_issue_write(struct netfs_io_stream *stream,
-				 struct netfs_io_subrequest *subreq,
-				 struct iov_iter *source)
+				 struct netfs_io_subrequest *subreq)
 {
 	struct netfs_io_request *wreq = subreq->rreq;
-	size_t size = subreq->len - subreq->transferred;
 
 	_enter("R=%x[%x],%zx", wreq->debug_id, subreq->debug_index, subreq->len);
 
 	if (test_bit(NETFS_SREQ_FAILED, &subreq->flags))
 		return netfs_write_subrequest_terminated(subreq, subreq->error, false);
 
-	// TODO: Use encrypted buffer
-	subreq->io_iter = *source;
-	iov_iter_advance(source, size);
-	iov_iter_truncate(&subreq->io_iter, size);
-
 	trace_netfs_sreq(subreq, netfs_sreq_trace_submit);
 	stream->issue_write(subreq);
 }
@@ -237,8 +230,15 @@ void netfs_reissue_write(struct netfs_io_stream *stream,
 			 struct netfs_io_subrequest *subreq,
 			 struct iov_iter *source)
 {
+	size_t size = subreq->len - subreq->transferred;
+
+	// TODO: Use encrypted buffer
+	subreq->io_iter = *source;
+	iov_iter_advance(source, size);
+	iov_iter_truncate(&subreq->io_iter, size);
+
 	__set_bit(NETFS_SREQ_IN_PROGRESS, &subreq->flags);
-	netfs_do_issue_write(stream, subreq, source);
+	netfs_do_issue_write(stream, subreq);
 }
 
 static void netfs_issue_write(struct netfs_io_request *wreq,
@@ -249,10 +249,8 @@ static void netfs_issue_write(struct netfs_io_request *wreq,
 	if (!subreq)
 		return;
 	stream->construct = NULL;
-
-	if (subreq->start + subreq->len > wreq->start + wreq->submitted)
-		WRITE_ONCE(wreq->submitted, subreq->start + subreq->len - wreq->start);
-	netfs_do_issue_write(stream, subreq, &wreq->io_iter);
+	subreq->io_iter.count = subreq->len;
+	netfs_do_issue_write(stream, subreq);
 }
 
 /*
@@ -464,10 +462,11 @@ static int netfs_write_folio(struct netfs_io_request *wreq,
 		if (choose_s < 0)
 			break;
 		stream = &wreq->io_streams[choose_s];
+		wreq->io_iter.iov_offset = stream->submit_off;
 
+		atomic64_set(&wreq->issued_to, fpos + stream->submit_off);
 		part = netfs_advance_write(wreq, stream, fpos + stream->submit_off,
 					   stream->submit_len, to_eof);
-		atomic64_set(&wreq->issued_to, fpos + stream->submit_off);
 		stream->submit_off += part;
 		stream->submit_max_len -= part;
 		if (part > stream->submit_len)
@@ -478,6 +477,8 @@ static int netfs_write_folio(struct netfs_io_request *wreq,
 			debug = true;
 	}
 
+	wreq->io_iter.iov_offset = 0;
+	iov_iter_advance(&wreq->io_iter, fsize);
 	atomic64_set(&wreq->issued_to, fpos + fsize);
 
 	if (!debug)
@@ -526,10 +527,10 @@ int netfs_writepages(struct address_space *mapping,
 	netfs_stat(&netfs_n_wh_writepages);
 
 	do {
-		_debug("wbiter %lx %llx", folio->index, wreq->start + wreq->submitted);
+		_debug("wbiter %lx %llx", folio->index, atomic64_read(&wreq->issued_to));
 
 		/* It appears we don't have to handle cyclic writeback wrapping. */
-		WARN_ON_ONCE(wreq && folio_pos(folio) < wreq->start + wreq->submitted);
+		WARN_ON_ONCE(wreq && folio_pos(folio) < atomic64_read(&wreq->issued_to));
 
 		if (netfs_folio_group(folio) != NETFS_FOLIO_COPY_TO_CACHE &&
 		    unlikely(!test_bit(NETFS_RREQ_UPLOAD_TO_SERVER, &wreq->flags))) {
@@ -673,6 +674,7 @@ int netfs_unbuffered_write(struct netfs_io_request *wreq, bool may_wait, size_t
 		part = netfs_advance_write(wreq, upload, start, len, false);
 		start += part;
 		len -= part;
+		iov_iter_advance(&wreq->io_iter, part);
 		if (test_bit(NETFS_RREQ_PAUSE, &wreq->flags)) {
 			trace_netfs_rreq(wreq, netfs_rreq_trace_wait_pause);
 			wait_on_bit(&wreq->flags, NETFS_RREQ_PAUSE, TASK_UNINTERRUPTIBLE);
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index f7b444f4f251..bd0e3d147822 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -257,7 +257,6 @@ struct netfs_io_request {
 	unsigned long long	i_size;		/* Size of the file */
 	unsigned long long	start;		/* Start position */
 	atomic64_t		issued_to;	/* Write issuer folio cursor */
-	unsigned long long	contiguity;	/* Tracking for gaps in the writeback sequence */
 	unsigned long long	collected_to;	/* Point we've collected to */
 	unsigned long long	cleaned_to;	/* Position we've cleaned folios to */
 	pgoff_t			no_unlock_folio; /* Don't unlock this folio after read */
diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h
index 4e13774a06e6..58bf23002fc1 100644
--- a/include/trace/events/netfs.h
+++ b/include/trace/events/netfs.h
@@ -512,33 +512,6 @@ TRACE_EVENT(netfs_collect,
 		      __entry->start + __entry->len)
 	    );
 
-TRACE_EVENT(netfs_collect_contig,
-	    TP_PROTO(const struct netfs_io_request *wreq, unsigned long long to,
-		     enum netfs_collect_contig_trace type),
-
-	    TP_ARGS(wreq, to, type),
-
-	    TP_STRUCT__entry(
-		    __field(unsigned int,		wreq)
-		    __field(enum netfs_collect_contig_trace, type)
-		    __field(unsigned long long,		contiguity)
-		    __field(unsigned long long,		to)
-			     ),
-
-	    TP_fast_assign(
-		    __entry->wreq	= wreq->debug_id;
-		    __entry->type	= type;
-		    __entry->contiguity	= wreq->contiguity;
-		    __entry->to		= to;
-			   ),
-
-	    TP_printk("R=%08x %llx -> %llx %s",
-		      __entry->wreq,
-		      __entry->contiguity,
-		      __entry->to,
-		      __print_symbolic(__entry->type, netfs_collect_contig_traces))
-	    );
-
 TRACE_EVENT(netfs_collect_sreq,
 	    TP_PROTO(const struct netfs_io_request *wreq,
 		     const struct netfs_io_subrequest *subreq),
@@ -610,7 +583,6 @@ TRACE_EVENT(netfs_collect_state,
 		    __field(unsigned int,	notes		)
 		    __field(unsigned long long,	collected_to	)
 		    __field(unsigned long long,	cleaned_to	)
-		    __field(unsigned long long,	contiguity	)
 			     ),
 
 	    TP_fast_assign(
@@ -618,12 +590,11 @@ TRACE_EVENT(netfs_collect_state,
 		    __entry->notes	= notes;
 		    __entry->collected_to = collected_to;
 		    __entry->cleaned_to	= wreq->cleaned_to;
-		    __entry->contiguity = wreq->contiguity;
 			   ),
 
-	    TP_printk("R=%08x cto=%llx fto=%llx ctg=%llx n=%x",
+	    TP_printk("R=%08x col=%llx cln=%llx n=%x",
 		      __entry->wreq, __entry->collected_to,
-		      __entry->cleaned_to, __entry->contiguity,
+		      __entry->cleaned_to,
 		      __entry->notes)
 	    );