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 */ 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 */ 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 */ 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 */ 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 */ 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