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 __set_bit(NETFS_RREQ_OFFLOAD_COLLECTION, &creq->flags); 114 trace_netfs_copy2cache(rreq, creq); 115 trace_netfs_write(creq, netfs_write_trace_copy_to_cache); 116 netfs_stat(&netfs_n_wh_copy_to_cache); 117 rreq->copy_to_cache = creq; 118 return creq; 119 120 cancel_put: 121 netfs_put_request(creq, netfs_rreq_trace_put_return); 122 cancel: 123 rreq->copy_to_cache = ERR_PTR(-ENOBUFS); 124 clear_bit(NETFS_RREQ_FOLIO_COPY_TO_CACHE, &rreq->flags); 125 return ERR_PTR(-ENOBUFS); 126 } 127 128 /* 129 * [DEPRECATED] Mark page as requiring copy-to-cache using PG_private_2 and add 130 * it to the copy write request. 131 */ 132 void netfs_pgpriv2_copy_to_cache(struct netfs_io_request *rreq, struct folio *folio) 133 { 134 struct netfs_io_request *creq = rreq->copy_to_cache; 135 136 if (!creq) 137 creq = netfs_pgpriv2_begin_copy_to_cache(rreq, folio); 138 if (IS_ERR(creq)) 139 return; 140 141 trace_netfs_folio(folio, netfs_folio_trace_copy_to_cache); 142 folio_start_private_2(folio); 143 netfs_pgpriv2_copy_folio(creq, folio); 144 } 145 146 /* 147 * [DEPRECATED] End writing to the cache, flushing out any outstanding writes. 148 */ 149 void netfs_pgpriv2_end_copy_to_cache(struct netfs_io_request *rreq) 150 { 151 struct netfs_io_request *creq = rreq->copy_to_cache; 152 153 if (IS_ERR_OR_NULL(creq)) 154 return; 155 156 netfs_issue_write(creq, &creq->io_streams[1]); 157 smp_wmb(); /* Write lists before ALL_QUEUED. */ 158 set_bit(NETFS_RREQ_ALL_QUEUED, &creq->flags); 159 trace_netfs_rreq(rreq, netfs_rreq_trace_end_copy_to_cache); 160 if (list_empty_careful(&creq->io_streams[1].subrequests)) 161 netfs_wake_collector(creq); 162 163 netfs_put_request(creq, netfs_rreq_trace_put_return); 164 creq->copy_to_cache = NULL; 165 } 166 167 /* 168 * [DEPRECATED] Remove the PG_private_2 mark from any folios we've finished 169 * copying. 170 */ 171 bool netfs_pgpriv2_unlock_copied_folios(struct netfs_io_request *creq) 172 { 173 struct folio_queue *folioq = creq->buffer.tail; 174 unsigned long long collected_to = creq->collected_to; 175 unsigned int slot = creq->buffer.first_tail_slot; 176 bool made_progress = false; 177 178 if (slot >= folioq_nr_slots(folioq)) { 179 folioq = rolling_buffer_delete_spent(&creq->buffer); 180 slot = 0; 181 } 182 183 for (;;) { 184 struct folio *folio; 185 unsigned long long fpos, fend; 186 size_t fsize, flen; 187 188 folio = folioq_folio(folioq, slot); 189 if (WARN_ONCE(!folio_test_private_2(folio), 190 "R=%08x: folio %lx is not marked private_2\n", 191 creq->debug_id, folio->index)) 192 trace_netfs_folio(folio, netfs_folio_trace_not_under_wback); 193 194 fpos = folio_pos(folio); 195 fsize = folio_size(folio); 196 flen = fsize; 197 198 fend = min_t(unsigned long long, fpos + flen, creq->i_size); 199 200 trace_netfs_collect_folio(creq, folio, fend, collected_to); 201 202 /* Unlock any folio we've transferred all of. */ 203 if (collected_to < fend) 204 break; 205 206 trace_netfs_folio(folio, netfs_folio_trace_end_copy); 207 folio_end_private_2(folio); 208 creq->cleaned_to = fpos + fsize; 209 made_progress = true; 210 211 /* Clean up the head folioq. If we clear an entire folioq, then 212 * we can get rid of it provided it's not also the tail folioq 213 * being filled by the issuer. 214 */ 215 folioq_clear(folioq, slot); 216 slot++; 217 if (slot >= folioq_nr_slots(folioq)) { 218 folioq = rolling_buffer_delete_spent(&creq->buffer); 219 if (!folioq) 220 goto done; 221 slot = 0; 222 } 223 224 if (fpos + fsize >= collected_to) 225 break; 226 } 227 228 creq->buffer.tail = folioq; 229 done: 230 creq->buffer.first_tail_slot = slot; 231 return made_progress; 232 } 233