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
|
// SPDX-License-Identifier: GPL-2.0-only
/* Network filesystem read subrequest retrying.
*
* Copyright (C) 2024 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <linux/fs.h>
#include <linux/slab.h>
#include "internal.h"
static void netfs_reissue_read(struct netfs_io_request *rreq,
struct netfs_io_subrequest *subreq)
{
struct iov_iter *io_iter = &subreq->io_iter;
if (iov_iter_is_folioq(io_iter)) {
subreq->curr_folioq = (struct folio_queue *)io_iter->folioq;
subreq->curr_folioq_slot = io_iter->folioq_slot;
subreq->curr_folio_order = subreq->curr_folioq->orders[subreq->curr_folioq_slot];
}
atomic_inc(&rreq->nr_outstanding);
__set_bit(NETFS_SREQ_IN_PROGRESS, &subreq->flags);
netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit);
subreq->rreq->netfs_ops->issue_read(subreq);
}
/*
* Go through the list of failed/short reads, retrying all retryable ones. We
* need to switch failed cache reads to network downloads.
*/
static void netfs_retry_read_subrequests(struct netfs_io_request *rreq)
{
struct netfs_io_subrequest *subreq;
struct netfs_io_stream *stream0 = &rreq->io_streams[0];
LIST_HEAD(sublist);
LIST_HEAD(queue);
_enter("R=%x", rreq->debug_id);
if (list_empty(&rreq->subrequests))
return;
if (rreq->netfs_ops->retry_request)
rreq->netfs_ops->retry_request(rreq, NULL);
/* If there's no renegotiation to do, just resend each retryable subreq
* up to the first permanently failed one.
*/
if (!rreq->netfs_ops->prepare_read &&
!test_bit(NETFS_RREQ_COPY_TO_CACHE, &rreq->flags)) {
struct netfs_io_subrequest *subreq;
list_for_each_entry(subreq, &rreq->subrequests, rreq_link) {
if (test_bit(NETFS_SREQ_FAILED, &subreq->flags))
break;
if (__test_and_clear_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags)) {
netfs_reset_iter(subreq);
netfs_reissue_read(rreq, subreq);
}
}
return;
}
/* Okay, we need to renegotiate all the download requests and flip any
* failed cache reads over to being download requests and negotiate
* those also. All fully successful subreqs have been removed from the
* list and any spare data from those has been donated.
*
* What we do is decant the list and rebuild it one subreq at a time so
* that we don't end up with donations jumping over a gap we're busy
* populating with smaller subrequests. In the event that the subreq
* we just launched finishes before we insert the next subreq, it'll
* fill in rreq->prev_donated instead.
* Note: Alternatively, we could split the tail subrequest right before
* we reissue it and fix up the donations under lock.
*/
list_splice_init(&rreq->subrequests, &queue);
do {
struct netfs_io_subrequest *from;
struct iov_iter source;
unsigned long long start, len;
size_t part, deferred_next_donated = 0;
bool boundary = false;
/* Go through the subreqs and find the next span of contiguous
* buffer that we then rejig (cifs, for example, needs the
* rsize renegotiating) and reissue.
*/
from = list_first_entry(&queue, struct netfs_io_subrequest, rreq_link);
list_move_tail(&from->rreq_link, &sublist);
start = from->start + from->transferred;
len = from->len - from->transferred;
_debug("from R=%08x[%x] s=%llx ctl=%zx/%zx/%zx",
rreq->debug_id, from->debug_index,
from->start, from->consumed, from->transferred, from->len);
if (test_bit(NETFS_SREQ_FAILED, &from->flags) ||
!test_bit(NETFS_SREQ_NEED_RETRY, &from->flags))
goto abandon;
deferred_next_donated = from->next_donated;
while ((subreq = list_first_entry_or_null(
&queue, struct netfs_io_subrequest, rreq_link))) {
if (subreq->start != start + len ||
subreq->transferred > 0 ||
!test_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags))
break;
list_move_tail(&subreq->rreq_link, &sublist);
len += subreq->len;
deferred_next_donated = subreq->next_donated;
if (test_bit(NETFS_SREQ_BOUNDARY, &subreq->flags))
break;
}
_debug(" - range: %llx-%llx %llx", start, start + len - 1, len);
/* Determine the set of buffers we're going to use. Each
* subreq gets a subset of a single overall contiguous buffer.
*/
netfs_reset_iter(from);
source = from->io_iter;
source.count = len;
/* Work through the sublist. */
while ((subreq = list_first_entry_or_null(
&sublist, struct netfs_io_subrequest, rreq_link))) {
list_del(&subreq->rreq_link);
subreq->source = NETFS_DOWNLOAD_FROM_SERVER;
subreq->start = start - subreq->transferred;
subreq->len = len + subreq->transferred;
stream0->sreq_max_len = subreq->len;
__clear_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags);
__set_bit(NETFS_SREQ_RETRYING, &subreq->flags);
spin_lock_bh(&rreq->lock);
list_add_tail(&subreq->rreq_link, &rreq->subrequests);
subreq->prev_donated += rreq->prev_donated;
rreq->prev_donated = 0;
trace_netfs_sreq(subreq, netfs_sreq_trace_retry);
spin_unlock_bh(&rreq->lock);
BUG_ON(!len);
/* Renegotiate max_len (rsize) */
if (rreq->netfs_ops->prepare_read(subreq) < 0) {
trace_netfs_sreq(subreq, netfs_sreq_trace_reprep_failed);
__set_bit(NETFS_SREQ_FAILED, &subreq->flags);
}
part = umin(len, stream0->sreq_max_len);
if (unlikely(rreq->io_streams[0].sreq_max_segs))
part = netfs_limit_iter(&source, 0, part, stream0->sreq_max_segs);
subreq->len = subreq->transferred + part;
subreq->io_iter = source;
iov_iter_truncate(&subreq->io_iter, part);
iov_iter_advance(&source, part);
len -= part;
start += part;
if (!len) {
if (boundary)
__set_bit(NETFS_SREQ_BOUNDARY, &subreq->flags);
subreq->next_donated = deferred_next_donated;
} else {
__clear_bit(NETFS_SREQ_BOUNDARY, &subreq->flags);
subreq->next_donated = 0;
}
netfs_reissue_read(rreq, subreq);
if (!len)
break;
/* If we ran out of subrequests, allocate another. */
if (list_empty(&sublist)) {
subreq = netfs_alloc_subrequest(rreq);
if (!subreq)
goto abandon;
subreq->source = NETFS_DOWNLOAD_FROM_SERVER;
subreq->start = start;
/* We get two refs, but need just one. */
netfs_put_subrequest(subreq, false, netfs_sreq_trace_new);
trace_netfs_sreq(subreq, netfs_sreq_trace_split);
list_add_tail(&subreq->rreq_link, &sublist);
}
}
/* If we managed to use fewer subreqs, we can discard the
* excess.
*/
while ((subreq = list_first_entry_or_null(
&sublist, struct netfs_io_subrequest, 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);
}
} while (!list_empty(&queue));
return;
/* If we hit ENOMEM, fail all remaining subrequests */
abandon:
list_splice_init(&sublist, &queue);
list_for_each_entry(subreq, &queue, rreq_link) {
if (!subreq->error)
subreq->error = -ENOMEM;
__clear_bit(NETFS_SREQ_FAILED, &subreq->flags);
__clear_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags);
__clear_bit(NETFS_SREQ_RETRYING, &subreq->flags);
}
spin_lock_bh(&rreq->lock);
list_splice_tail_init(&queue, &rreq->subrequests);
spin_unlock_bh(&rreq->lock);
}
/*
* Retry reads.
*/
void netfs_retry_reads(struct netfs_io_request *rreq)
{
trace_netfs_rreq(rreq, netfs_rreq_trace_resubmit);
atomic_inc(&rreq->nr_outstanding);
netfs_retry_read_subrequests(rreq);
if (atomic_dec_and_test(&rreq->nr_outstanding))
netfs_rreq_terminated(rreq, false);
}
/*
* Unlock any the pages that haven't been unlocked yet due to abandoned
* subrequests.
*/
void netfs_unlock_abandoned_read_pages(struct netfs_io_request *rreq)
{
struct folio_queue *p;
for (p = rreq->buffer; p; p = p->next) {
for (int slot = 0; slot < folioq_count(p); slot++) {
struct folio *folio = folioq_folio(p, slot);
if (folio && !folioq_is_marked2(p, slot)) {
trace_netfs_folio(folio, netfs_folio_trace_abandon);
folio_unlock(folio);
}
}
}
}
|
