1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Read with PG_private_2 [DEPRECATED].
3 *
4 * Copyright (C) 2024 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8 #include <linux/export.h>
9 #include <linux/fs.h>
10 #include <linux/mm.h>
11 #include <linux/pagemap.h>
12 #include <linux/slab.h>
13 #include <linux/task_io_accounting_ops.h>
14 #include "internal.h"
15
16 /*
17 * [DEPRECATED] Mark page as requiring copy-to-cache using PG_private_2. The
18 * third mark in the folio queue is used to indicate that this folio needs
19 * writing.
20 */
21 void netfs_pgpriv2_mark_copy_to_cache(struct netfs_io_subrequest *subreq,
22 struct netfs_io_request *rreq,
23 struct folio_queue *folioq,
24 int slot)
25 {
26 struct folio *folio = folioq_folio(folioq, slot);
27
28 trace_netfs_folio(folio, netfs_folio_trace_copy_to_cache);
29 folio_start_private_2(folio);
30 folioq_mark3(folioq, slot);
31 }
32
33 /*
34 * [DEPRECATED] Cancel PG_private_2 on all marked folios in the event of an
35 * unrecoverable error.
36 */
37 static void netfs_pgpriv2_cancel(struct folio_queue *folioq)
38 {
39 struct folio *folio;
40 int slot;
41
42 while (folioq) {
43 if (!folioq->marks3) {
44 folioq = folioq->next;
45 continue;
46 }
47
48 slot = __ffs(folioq->marks3);
49 folio = folioq_folio(folioq, slot);
50
51 trace_netfs_folio(folio, netfs_folio_trace_cancel_copy);
52 folio_end_private_2(folio);
53 folioq_unmark3(folioq, slot);
54 }
55 }
56
57 /*
58 * [DEPRECATED] Copy a folio to the cache with PG_private_2 set.
59 */
60 static int netfs_pgpriv2_copy_folio(struct netfs_io_request *wreq, struct folio *folio)
61 {
62 struct netfs_io_stream *cache = &wreq->io_streams[1];
63 size_t fsize = folio_size(folio), flen = fsize;
64 loff_t fpos = folio_pos(folio), i_size;
65 bool to_eof = false;
66
67 _enter("");
68
69 /* netfs_perform_write() may shift i_size around the page or from out
70 * of the page to beyond it, but cannot move i_size into or through the
71 * page since we have it locked.
72 */
73 i_size = i_size_read(wreq->inode);
74
75 if (fpos >= i_size) {
76 /* mmap beyond eof. */
77 _debug("beyond eof");
78 folio_end_private_2(folio);
79 return 0;
80 }
81
82 if (fpos + fsize > wreq->i_size)
83 wreq->i_size = i_size;
84
85 if (flen > i_size - fpos) {
86 flen = i_size - fpos;
87 to_eof = true;
88 } else if (flen == i_size - fpos) {
89 to_eof = true;
90 }
91
92 _debug("folio %zx %zx", flen, fsize);
93
94 trace_netfs_folio(folio, netfs_folio_trace_store_copy);
95
96 /* Attach the folio to the rolling buffer. */
97 if (netfs_buffer_append_folio(wreq, folio, false) < 0)
98 return -ENOMEM;
99
100 cache->submit_extendable_to = fsize;
101 cache->submit_off = 0;
102 cache->submit_len = flen;
103
104 /* Attach the folio to one or more subrequests. For a big folio, we
105 * could end up with thousands of subrequests if the wsize is small -
106 * but we might need to wait during the creation of subrequests for
107 * network resources (eg. SMB credits).
108 */
109 do {
110 ssize_t part;
111
112 wreq->io_iter.iov_offset = cache->submit_off;
113
114 atomic64_set(&wreq->issued_to, fpos + cache->submit_off);
115 cache->submit_extendable_to = fsize - cache->submit_off;
116 part = netfs_advance_write(wreq, cache, fpos + cache->submit_off,
117 cache->submit_len, to_eof);
118 cache->submit_off += part;
119 if (part > cache->submit_len)
120 cache->submit_len = 0;
121 else
122 cache->submit_len -= part;
123 } while (cache->submit_len > 0);
124
125 wreq->io_iter.iov_offset = 0;
126 iov_iter_advance(&wreq->io_iter, fsize);
127 atomic64_set(&wreq->issued_to, fpos + fsize);
128
129 if (flen < fsize)
130 netfs_issue_write(wreq, cache);
131
132 _leave(" = 0");
133 return 0;
134 }
135
136 /*
137 * [DEPRECATED] Go through the buffer and write any folios that are marked with
138 * the third mark to the cache.
139 */
140 void netfs_pgpriv2_write_to_the_cache(struct netfs_io_request *rreq)
141 {
142 struct netfs_io_request *wreq;
143 struct folio_queue *folioq;
144 struct folio *folio;
145 int error = 0;
146 int slot = 0;
147
148 _enter("");
149
150 if (!fscache_resources_valid(&rreq->cache_resources))
151 goto couldnt_start;
152
153 /* Need the first folio to be able to set up the op. */
154 for (folioq = rreq->buffer; folioq; folioq = folioq->next) {
155 if (folioq->marks3) {
156 slot = __ffs(folioq->marks3);
157 break;
158 }
159 }
160 if (!folioq)
161 return;
162 folio = folioq_folio(folioq, slot);
163
164 wreq = netfs_create_write_req(rreq->mapping, NULL, folio_pos(folio),
165 NETFS_PGPRIV2_COPY_TO_CACHE);
166 if (IS_ERR(wreq)) {
167 kleave(" [create %ld]", PTR_ERR(wreq));
168 goto couldnt_start;
169 }
170
171 trace_netfs_write(wreq, netfs_write_trace_copy_to_cache);
172 netfs_stat(&netfs_n_wh_copy_to_cache);
173
174 for (;;) {
175 error = netfs_pgpriv2_copy_folio(wreq, folio);
176 if (error < 0)
177 break;
178
179 folioq_unmark3(folioq, slot);
180 if (!folioq->marks3) {
181 folioq = folioq->next;
182 if (!folioq)
183 break;
184 }
185
186 slot = __ffs(folioq->marks3);
187 folio = folioq_folio(folioq, slot);
188 }
189
190 netfs_issue_write(wreq, &wreq->io_streams[1]);
191 smp_wmb(); /* Write lists before ALL_QUEUED. */
192 set_bit(NETFS_RREQ_ALL_QUEUED, &wreq->flags);
193
194 netfs_put_request(wreq, false, netfs_rreq_trace_put_return);
195 _leave(" = %d", error);
196 couldnt_start:
197 netfs_pgpriv2_cancel(rreq->buffer);
198 }
199
200 /*
201 * [DEPRECATED] Remove the PG_private_2 mark from any folios we've finished
202 * copying.
203 */
204 bool netfs_pgpriv2_unlock_copied_folios(struct netfs_io_request *wreq)
205 {
206 struct folio_queue *folioq = wreq->buffer;
207 unsigned long long collected_to = wreq->collected_to;
208 unsigned int slot = wreq->buffer_head_slot;
209 bool made_progress = false;
210
211 if (slot >= folioq_nr_slots(folioq)) {
212 folioq = netfs_delete_buffer_head(wreq);
213 slot = 0;
214 }
215
216 for (;;) {
217 struct folio *folio;
218 unsigned long long fpos, fend;
219 size_t fsize, flen;
220
221 folio = folioq_folio(folioq, slot);
222 if (WARN_ONCE(!folio_test_private_2(folio),
223 "R=%08x: folio %lx is not marked private_2\n",
224 wreq->debug_id, folio->index))
225 trace_netfs_folio(folio, netfs_folio_trace_not_under_wback);
226
227 fpos = folio_pos(folio);
228 fsize = folio_size(folio);
229 flen = fsize;
230
231 fend = min_t(unsigned long long, fpos + flen, wreq->i_size);
232
233 trace_netfs_collect_folio(wreq, folio, fend, collected_to);
234
235 /* Unlock any folio we've transferred all of. */
236 if (collected_to < fend)
237 break;
238
239 trace_netfs_folio(folio, netfs_folio_trace_end_copy);
240 folio_end_private_2(folio);
241 wreq->cleaned_to = fpos + fsize;
242 made_progress = true;
243
244 /* Clean up the head folioq. If we clear an entire folioq, then
245 * we can get rid of it provided it's not also the tail folioq
246 * being filled by the issuer.
247 */
248 folioq_clear(folioq, slot);
249 slot++;
250 if (slot >= folioq_nr_slots(folioq)) {
251 if (READ_ONCE(wreq->buffer_tail) == folioq)
252 break;
253 folioq = netfs_delete_buffer_head(wreq);
254 slot = 0;
255 }
256
257 if (fpos + fsize >= collected_to)
258 break;
259 }
260
261 wreq->buffer = folioq;
262 wreq->buffer_head_slot = slot;
263 return made_progress;
264 }
265
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