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] Copy a folio to the cache with PG_private_2 set.
18 */
netfs_pgpriv2_copy_folio(struct netfs_io_request * creq,struct folio * folio)19 static void netfs_pgpriv2_copy_folio(struct netfs_io_request *creq, struct folio *folio)
20 {
21 struct netfs_io_stream *cache = &creq->io_streams[1];
22 size_t fsize = folio_size(folio), flen = fsize;
23 loff_t fpos = folio_pos(folio), i_size;
24 bool to_eof = false;
25
26 _enter("");
27
28 /* netfs_perform_write() may shift i_size around the page or from out
29 * of the page to beyond it, but cannot move i_size into or through the
30 * page since we have it locked.
31 */
32 i_size = i_size_read(creq->inode);
33
34 if (fpos >= i_size) {
35 /* mmap beyond eof. */
36 _debug("beyond eof");
37 folio_end_private_2(folio);
38 return;
39 }
40
41 if (fpos + fsize > creq->i_size)
42 creq->i_size = i_size;
43
44 if (flen > i_size - fpos) {
45 flen = i_size - fpos;
46 to_eof = true;
47 } else if (flen == i_size - fpos) {
48 to_eof = true;
49 }
50
51 _debug("folio %zx %zx", flen, fsize);
52
53 trace_netfs_folio(folio, netfs_folio_trace_store_copy);
54
55 /* Attach the folio to the rolling buffer. */
56 if (rolling_buffer_append(&creq->buffer, folio, 0) < 0) {
57 clear_bit(NETFS_RREQ_FOLIO_COPY_TO_CACHE, &creq->flags);
58 return;
59 }
60
61 cache->submit_extendable_to = fsize;
62 cache->submit_off = 0;
63 cache->submit_len = flen;
64
65 /* Attach the folio to one or more subrequests. For a big folio, we
66 * could end up with thousands of subrequests if the wsize is small -
67 * but we might need to wait during the creation of subrequests for
68 * network resources (eg. SMB credits).
69 */
70 do {
71 ssize_t part;
72
73 creq->buffer.iter.iov_offset = cache->submit_off;
74
75 atomic64_set(&creq->issued_to, fpos + cache->submit_off);
76 cache->submit_extendable_to = fsize - cache->submit_off;
77 part = netfs_advance_write(creq, cache, fpos + cache->submit_off,
78 cache->submit_len, to_eof);
79 cache->submit_off += part;
80 if (part > cache->submit_len)
81 cache->submit_len = 0;
82 else
83 cache->submit_len -= part;
84 } while (cache->submit_len > 0);
85
86 creq->buffer.iter.iov_offset = 0;
87 rolling_buffer_advance(&creq->buffer, fsize);
88 atomic64_set(&creq->issued_to, fpos + fsize);
89
90 if (flen < fsize)
91 netfs_issue_write(creq, cache);
92 }
93
94 /*
95 * [DEPRECATED] Set up copying to the cache.
96 */
netfs_pgpriv2_begin_copy_to_cache(struct netfs_io_request * rreq,struct folio * folio)97 static struct netfs_io_request *netfs_pgpriv2_begin_copy_to_cache(
98 struct netfs_io_request *rreq, struct folio *folio)
99 {
100 struct netfs_io_request *creq;
101
102 if (!fscache_resources_valid(&rreq->cache_resources))
103 goto cancel;
104
105 creq = netfs_create_write_req(rreq->mapping, NULL, folio_pos(folio),
106 NETFS_PGPRIV2_COPY_TO_CACHE);
107 if (IS_ERR(creq))
108 goto cancel;
109
110 if (!creq->io_streams[1].avail)
111 goto cancel_put;
112
113 trace_netfs_write(creq, netfs_write_trace_copy_to_cache);
114 netfs_stat(&netfs_n_wh_copy_to_cache);
115 rreq->copy_to_cache = creq;
116 return creq;
117
118 cancel_put:
119 netfs_put_request(creq, false, netfs_rreq_trace_put_return);
120 cancel:
121 rreq->copy_to_cache = ERR_PTR(-ENOBUFS);
122 clear_bit(NETFS_RREQ_FOLIO_COPY_TO_CACHE, &rreq->flags);
123 return ERR_PTR(-ENOBUFS);
124 }
125
126 /*
127 * [DEPRECATED] Mark page as requiring copy-to-cache using PG_private_2 and add
128 * it to the copy write request.
129 */
netfs_pgpriv2_copy_to_cache(struct netfs_io_request * rreq,struct folio * folio)130 void netfs_pgpriv2_copy_to_cache(struct netfs_io_request *rreq, struct folio *folio)
131 {
132 struct netfs_io_request *creq = rreq->copy_to_cache;
133
134 if (!creq)
135 creq = netfs_pgpriv2_begin_copy_to_cache(rreq, folio);
136 if (IS_ERR(creq))
137 return;
138
139 trace_netfs_folio(folio, netfs_folio_trace_copy_to_cache);
140 folio_start_private_2(folio);
141 netfs_pgpriv2_copy_folio(creq, folio);
142 }
143
144 /*
145 * [DEPRECATED] End writing to the cache, flushing out any outstanding writes.
146 */
netfs_pgpriv2_end_copy_to_cache(struct netfs_io_request * rreq)147 void netfs_pgpriv2_end_copy_to_cache(struct netfs_io_request *rreq)
148 {
149 struct netfs_io_request *creq = rreq->copy_to_cache;
150
151 if (IS_ERR_OR_NULL(creq))
152 return;
153
154 netfs_issue_write(creq, &creq->io_streams[1]);
155 smp_wmb(); /* Write lists before ALL_QUEUED. */
156 set_bit(NETFS_RREQ_ALL_QUEUED, &creq->flags);
157
158 netfs_put_request(creq, false, netfs_rreq_trace_put_return);
159 creq->copy_to_cache = NULL;
160 }
161
162 /*
163 * [DEPRECATED] Remove the PG_private_2 mark from any folios we've finished
164 * copying.
165 */
netfs_pgpriv2_unlock_copied_folios(struct netfs_io_request * creq)166 bool netfs_pgpriv2_unlock_copied_folios(struct netfs_io_request *creq)
167 {
168 struct folio_queue *folioq = creq->buffer.tail;
169 unsigned long long collected_to = creq->collected_to;
170 unsigned int slot = creq->buffer.first_tail_slot;
171 bool made_progress = false;
172
173 if (slot >= folioq_nr_slots(folioq)) {
174 folioq = rolling_buffer_delete_spent(&creq->buffer);
175 slot = 0;
176 }
177
178 for (;;) {
179 struct folio *folio;
180 unsigned long long fpos, fend;
181 size_t fsize, flen;
182
183 folio = folioq_folio(folioq, slot);
184 if (WARN_ONCE(!folio_test_private_2(folio),
185 "R=%08x: folio %lx is not marked private_2\n",
186 creq->debug_id, folio->index))
187 trace_netfs_folio(folio, netfs_folio_trace_not_under_wback);
188
189 fpos = folio_pos(folio);
190 fsize = folio_size(folio);
191 flen = fsize;
192
193 fend = min_t(unsigned long long, fpos + flen, creq->i_size);
194
195 trace_netfs_collect_folio(creq, folio, fend, collected_to);
196
197 /* Unlock any folio we've transferred all of. */
198 if (collected_to < fend)
199 break;
200
201 trace_netfs_folio(folio, netfs_folio_trace_end_copy);
202 folio_end_private_2(folio);
203 creq->cleaned_to = fpos + fsize;
204 made_progress = true;
205
206 /* Clean up the head folioq. If we clear an entire folioq, then
207 * we can get rid of it provided it's not also the tail folioq
208 * being filled by the issuer.
209 */
210 folioq_clear(folioq, slot);
211 slot++;
212 if (slot >= folioq_nr_slots(folioq)) {
213 folioq = rolling_buffer_delete_spent(&creq->buffer);
214 if (!folioq)
215 goto done;
216 slot = 0;
217 }
218
219 if (fpos + fsize >= collected_to)
220 break;
221 }
222
223 creq->buffer.tail = folioq;
224 done:
225 creq->buffer.first_tail_slot = slot;
226 return made_progress;
227 }
228