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, creq->gfp) < 0) { 57 folio_end_private_2(folio); 58 clear_bit(NETFS_RREQ_FOLIO_COPY_TO_CACHE, &creq->flags); 59 return; 60 } 61 62 cache->submit_extendable_to = fsize; 63 cache->submit_off = 0; 64 cache->submit_len = flen; 65 66 /* Attach the folio to one or more subrequests. For a big folio, we 67 * could end up with thousands of subrequests if the wsize is small - 68 * but we might need to wait during the creation of subrequests for 69 * network resources (eg. SMB credits). 70 */ 71 do { 72 ssize_t part; 73 74 creq->buffer.iter.iov_offset = cache->submit_off; 75 76 atomic64_set(&creq->issued_to, fpos + cache->submit_off); 77 cache->submit_extendable_to = fsize - cache->submit_off; 78 part = netfs_advance_write(creq, cache, fpos + cache->submit_off, 79 cache->submit_len, to_eof); 80 cache->submit_off += part; 81 if (part > cache->submit_len) 82 cache->submit_len = 0; 83 else 84 cache->submit_len -= part; 85 } while (cache->submit_len > 0); 86 87 creq->buffer.iter.iov_offset = 0; 88 rolling_buffer_advance(&creq->buffer, fsize); 89 atomic64_set(&creq->issued_to, fpos + fsize); 90 91 if (flen < fsize) 92 netfs_issue_write(creq, cache); 93 } 94 95 /* 96 * [DEPRECATED] Set up copying to the cache. 97 */ 98 static struct netfs_io_request *netfs_pgpriv2_begin_copy_to_cache( 99 struct netfs_io_request *rreq, struct folio *folio) 100 { 101 struct netfs_io_request *creq; 102 103 if (!fscache_resources_valid(&rreq->cache_resources)) 104 goto cancel; 105 106 creq = netfs_create_write_req(rreq->mapping, NULL, folio_pos(folio), 107 NETFS_PGPRIV2_COPY_TO_CACHE); 108 if (IS_ERR(creq)) 109 goto cancel; 110 111 if (!creq->io_streams[1].avail) 112 goto cancel_put; 113 114 __set_bit(NETFS_RREQ_OFFLOAD_COLLECTION, &creq->flags); 115 trace_netfs_copy2cache(rreq, creq); 116 trace_netfs_write(creq, netfs_write_trace_copy_to_cache); 117 netfs_stat(&netfs_n_wh_copy_to_cache); 118 rreq->copy_to_cache = creq; 119 return creq; 120 121 cancel_put: 122 netfs_put_failed_request(creq); 123 cancel: 124 rreq->copy_to_cache = ERR_PTR(-ENOBUFS); 125 clear_bit(NETFS_RREQ_FOLIO_COPY_TO_CACHE, &rreq->flags); 126 return ERR_PTR(-ENOBUFS); 127 } 128 129 /* 130 * [DEPRECATED] Mark page as requiring copy-to-cache using PG_private_2 and add 131 * it to the copy write request. 132 */ 133 void netfs_pgpriv2_copy_to_cache(struct netfs_io_request *rreq, struct folio *folio) 134 { 135 struct netfs_io_request *creq = rreq->copy_to_cache; 136 137 if (!creq) 138 creq = netfs_pgpriv2_begin_copy_to_cache(rreq, folio); 139 if (IS_ERR(creq)) 140 return; 141 142 trace_netfs_folio(folio, netfs_folio_trace_copy_to_cache); 143 folio_start_private_2(folio); 144 netfs_pgpriv2_copy_folio(creq, folio); 145 } 146 147 /* 148 * [DEPRECATED] End writing to the cache, flushing out any outstanding writes. 149 */ 150 void netfs_pgpriv2_end_copy_to_cache(struct netfs_io_request *rreq) 151 { 152 struct netfs_io_request *creq = rreq->copy_to_cache; 153 154 if (IS_ERR_OR_NULL(creq)) 155 return; 156 157 netfs_issue_write(creq, &creq->io_streams[1]); 158 smp_wmb(); /* Write lists before ALL_QUEUED. */ 159 set_bit(NETFS_RREQ_ALL_QUEUED, &creq->flags); 160 trace_netfs_rreq(rreq, netfs_rreq_trace_end_copy_to_cache); 161 if (list_empty_careful(&creq->io_streams[1].subrequests)) 162 netfs_wake_collector(creq); 163 164 netfs_put_request(creq, netfs_rreq_trace_put_return); 165 creq->copy_to_cache = NULL; 166 } 167 168 /* 169 * [DEPRECATED] Remove the PG_private_2 mark from any folios we've finished 170 * copying. 171 */ 172 bool netfs_pgpriv2_unlock_copied_folios(struct netfs_io_request *creq) 173 { 174 struct folio_queue *folioq = creq->buffer.tail; 175 unsigned long long collected_to = creq->collected_to; 176 unsigned int slot = creq->buffer.first_tail_slot; 177 bool made_progress = false; 178 179 if (slot >= folioq_nr_slots(folioq)) { 180 folioq = rolling_buffer_delete_spent(&creq->buffer); 181 slot = 0; 182 } 183 184 for (;;) { 185 struct folio *folio; 186 unsigned long long fpos, fend; 187 size_t fsize, flen; 188 189 folio = folioq_folio(folioq, slot); 190 if (WARN_ONCE(!folio_test_private_2(folio), 191 "R=%08x: folio %lx is not marked private_2\n", 192 creq->debug_id, folio->index)) 193 trace_netfs_folio(folio, netfs_folio_trace_not_under_wback); 194 195 fpos = folio_pos(folio); 196 fsize = folio_size(folio); 197 flen = fsize; 198 199 fend = min_t(unsigned long long, fpos + flen, creq->i_size); 200 201 trace_netfs_collect_folio(creq, folio, fend, collected_to); 202 203 /* Unlock any folio we've transferred all of. */ 204 if (collected_to < fend) 205 break; 206 207 trace_netfs_folio(folio, netfs_folio_trace_end_copy); 208 folio_end_private_2(folio); 209 creq->cleaned_to = fpos + fsize; 210 made_progress = true; 211 212 /* Clean up the head folioq. If we clear an entire folioq, then 213 * we can get rid of it provided it's not also the tail folioq 214 * being filled by the issuer. 215 */ 216 folioq_clear(folioq, slot); 217 slot++; 218 if (slot >= folioq_nr_slots(folioq)) { 219 folioq = rolling_buffer_delete_spent(&creq->buffer); 220 if (!folioq) 221 goto done; 222 slot = 0; 223 } 224 225 if (fpos + fsize >= collected_to) 226 break; 227 } 228 229 creq->buffer.tail = folioq; 230 done: 231 creq->buffer.first_tail_slot = slot; 232 return made_progress; 233 } 234