1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2017-2018 HUAWEI, Inc. 4 * http://www.huawei.com/ 5 * Created by Gao Xiang <gaoxiang25@huawei.com> 6 */ 7 #include "internal.h" 8 #include <linux/prefetch.h> 9 10 #include <trace/events/erofs.h> 11 12 static void erofs_readendio(struct bio *bio) 13 { 14 struct bio_vec *bvec; 15 blk_status_t err = bio->bi_status; 16 struct bvec_iter_all iter_all; 17 18 bio_for_each_segment_all(bvec, bio, iter_all) { 19 struct page *page = bvec->bv_page; 20 21 /* page is already locked */ 22 DBG_BUGON(PageUptodate(page)); 23 24 if (err) 25 SetPageError(page); 26 else 27 SetPageUptodate(page); 28 29 unlock_page(page); 30 /* page could be reclaimed now */ 31 } 32 bio_put(bio); 33 } 34 35 struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr) 36 { 37 struct inode *const bd_inode = sb->s_bdev->bd_inode; 38 struct address_space *const mapping = bd_inode->i_mapping; 39 40 return read_cache_page_gfp(mapping, blkaddr, 41 mapping_gfp_constraint(mapping, ~__GFP_FS)); 42 } 43 44 static int erofs_map_blocks_flatmode(struct inode *inode, 45 struct erofs_map_blocks *map, 46 int flags) 47 { 48 int err = 0; 49 erofs_blk_t nblocks, lastblk; 50 u64 offset = map->m_la; 51 struct erofs_inode *vi = EROFS_I(inode); 52 bool tailendpacking = (vi->datalayout == EROFS_INODE_FLAT_INLINE); 53 54 trace_erofs_map_blocks_flatmode_enter(inode, map, flags); 55 56 nblocks = DIV_ROUND_UP(inode->i_size, PAGE_SIZE); 57 lastblk = nblocks - tailendpacking; 58 59 if (offset >= inode->i_size) { 60 /* leave out-of-bound access unmapped */ 61 map->m_flags = 0; 62 map->m_plen = 0; 63 goto out; 64 } 65 66 /* there is no hole in flatmode */ 67 map->m_flags = EROFS_MAP_MAPPED; 68 69 if (offset < blknr_to_addr(lastblk)) { 70 map->m_pa = blknr_to_addr(vi->raw_blkaddr) + map->m_la; 71 map->m_plen = blknr_to_addr(lastblk) - offset; 72 } else if (tailendpacking) { 73 /* 2 - inode inline B: inode, [xattrs], inline last blk... */ 74 struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb); 75 76 map->m_pa = iloc(sbi, vi->nid) + vi->inode_isize + 77 vi->xattr_isize + erofs_blkoff(map->m_la); 78 map->m_plen = inode->i_size - offset; 79 80 /* inline data should be located in one meta block */ 81 if (erofs_blkoff(map->m_pa) + map->m_plen > PAGE_SIZE) { 82 erofs_err(inode->i_sb, 83 "inline data cross block boundary @ nid %llu", 84 vi->nid); 85 DBG_BUGON(1); 86 err = -EFSCORRUPTED; 87 goto err_out; 88 } 89 90 map->m_flags |= EROFS_MAP_META; 91 } else { 92 erofs_err(inode->i_sb, 93 "internal error @ nid: %llu (size %llu), m_la 0x%llx", 94 vi->nid, inode->i_size, map->m_la); 95 DBG_BUGON(1); 96 err = -EIO; 97 goto err_out; 98 } 99 100 out: 101 map->m_llen = map->m_plen; 102 103 err_out: 104 trace_erofs_map_blocks_flatmode_exit(inode, map, flags, 0); 105 return err; 106 } 107 108 int erofs_map_blocks(struct inode *inode, 109 struct erofs_map_blocks *map, int flags) 110 { 111 if (erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout)) { 112 int err = z_erofs_map_blocks_iter(inode, map, flags); 113 114 if (map->mpage) { 115 put_page(map->mpage); 116 map->mpage = NULL; 117 } 118 return err; 119 } 120 return erofs_map_blocks_flatmode(inode, map, flags); 121 } 122 123 static inline struct bio *erofs_read_raw_page(struct bio *bio, 124 struct address_space *mapping, 125 struct page *page, 126 erofs_off_t *last_block, 127 unsigned int nblocks, 128 bool ra) 129 { 130 struct inode *const inode = mapping->host; 131 struct super_block *const sb = inode->i_sb; 132 erofs_off_t current_block = (erofs_off_t)page->index; 133 int err; 134 135 DBG_BUGON(!nblocks); 136 137 if (PageUptodate(page)) { 138 err = 0; 139 goto has_updated; 140 } 141 142 /* note that for readpage case, bio also equals to NULL */ 143 if (bio && 144 /* not continuous */ 145 *last_block + 1 != current_block) { 146 submit_bio_retry: 147 submit_bio(bio); 148 bio = NULL; 149 } 150 151 if (!bio) { 152 struct erofs_map_blocks map = { 153 .m_la = blknr_to_addr(current_block), 154 }; 155 erofs_blk_t blknr; 156 unsigned int blkoff; 157 158 err = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW); 159 if (err) 160 goto err_out; 161 162 /* zero out the holed page */ 163 if (!(map.m_flags & EROFS_MAP_MAPPED)) { 164 zero_user_segment(page, 0, PAGE_SIZE); 165 SetPageUptodate(page); 166 167 /* imply err = 0, see erofs_map_blocks */ 168 goto has_updated; 169 } 170 171 /* for RAW access mode, m_plen must be equal to m_llen */ 172 DBG_BUGON(map.m_plen != map.m_llen); 173 174 blknr = erofs_blknr(map.m_pa); 175 blkoff = erofs_blkoff(map.m_pa); 176 177 /* deal with inline page */ 178 if (map.m_flags & EROFS_MAP_META) { 179 void *vsrc, *vto; 180 struct page *ipage; 181 182 DBG_BUGON(map.m_plen > PAGE_SIZE); 183 184 ipage = erofs_get_meta_page(inode->i_sb, blknr); 185 186 if (IS_ERR(ipage)) { 187 err = PTR_ERR(ipage); 188 goto err_out; 189 } 190 191 vsrc = kmap_atomic(ipage); 192 vto = kmap_atomic(page); 193 memcpy(vto, vsrc + blkoff, map.m_plen); 194 memset(vto + map.m_plen, 0, PAGE_SIZE - map.m_plen); 195 kunmap_atomic(vto); 196 kunmap_atomic(vsrc); 197 flush_dcache_page(page); 198 199 SetPageUptodate(page); 200 /* TODO: could we unlock the page earlier? */ 201 unlock_page(ipage); 202 put_page(ipage); 203 204 /* imply err = 0, see erofs_map_blocks */ 205 goto has_updated; 206 } 207 208 /* pa must be block-aligned for raw reading */ 209 DBG_BUGON(erofs_blkoff(map.m_pa)); 210 211 /* max # of continuous pages */ 212 if (nblocks > DIV_ROUND_UP(map.m_plen, PAGE_SIZE)) 213 nblocks = DIV_ROUND_UP(map.m_plen, PAGE_SIZE); 214 if (nblocks > BIO_MAX_PAGES) 215 nblocks = BIO_MAX_PAGES; 216 217 bio = bio_alloc(GFP_NOIO, nblocks); 218 219 bio->bi_end_io = erofs_readendio; 220 bio_set_dev(bio, sb->s_bdev); 221 bio->bi_iter.bi_sector = (sector_t)blknr << 222 LOG_SECTORS_PER_BLOCK; 223 bio->bi_opf = REQ_OP_READ; 224 } 225 226 err = bio_add_page(bio, page, PAGE_SIZE, 0); 227 /* out of the extent or bio is full */ 228 if (err < PAGE_SIZE) 229 goto submit_bio_retry; 230 231 *last_block = current_block; 232 233 /* shift in advance in case of it followed by too many gaps */ 234 if (bio->bi_iter.bi_size >= bio->bi_max_vecs * PAGE_SIZE) { 235 /* err should reassign to 0 after submitting */ 236 err = 0; 237 goto submit_bio_out; 238 } 239 240 return bio; 241 242 err_out: 243 /* for sync reading, set page error immediately */ 244 if (!ra) { 245 SetPageError(page); 246 ClearPageUptodate(page); 247 } 248 has_updated: 249 unlock_page(page); 250 251 /* if updated manually, continuous pages has a gap */ 252 if (bio) 253 submit_bio_out: 254 submit_bio(bio); 255 return err ? ERR_PTR(err) : NULL; 256 } 257 258 /* 259 * since we dont have write or truncate flows, so no inode 260 * locking needs to be held at the moment. 261 */ 262 static int erofs_raw_access_readpage(struct file *file, struct page *page) 263 { 264 erofs_off_t last_block; 265 struct bio *bio; 266 267 trace_erofs_readpage(page, true); 268 269 bio = erofs_read_raw_page(NULL, page->mapping, 270 page, &last_block, 1, false); 271 272 if (IS_ERR(bio)) 273 return PTR_ERR(bio); 274 275 DBG_BUGON(bio); /* since we have only one bio -- must be NULL */ 276 return 0; 277 } 278 279 static int erofs_raw_access_readpages(struct file *filp, 280 struct address_space *mapping, 281 struct list_head *pages, 282 unsigned int nr_pages) 283 { 284 erofs_off_t last_block; 285 struct bio *bio = NULL; 286 gfp_t gfp = readahead_gfp_mask(mapping); 287 struct page *page = list_last_entry(pages, struct page, lru); 288 289 trace_erofs_readpages(mapping->host, page, nr_pages, true); 290 291 for (; nr_pages; --nr_pages) { 292 page = list_entry(pages->prev, struct page, lru); 293 294 prefetchw(&page->flags); 295 list_del(&page->lru); 296 297 if (!add_to_page_cache_lru(page, mapping, page->index, gfp)) { 298 bio = erofs_read_raw_page(bio, mapping, page, 299 &last_block, nr_pages, true); 300 301 /* all the page errors are ignored when readahead */ 302 if (IS_ERR(bio)) { 303 pr_err("%s, readahead error at page %lu of nid %llu\n", 304 __func__, page->index, 305 EROFS_I(mapping->host)->nid); 306 307 bio = NULL; 308 } 309 } 310 311 /* pages could still be locked */ 312 put_page(page); 313 } 314 DBG_BUGON(!list_empty(pages)); 315 316 /* the rare case (end in gaps) */ 317 if (bio) 318 submit_bio(bio); 319 return 0; 320 } 321 322 static int erofs_get_block(struct inode *inode, sector_t iblock, 323 struct buffer_head *bh, int create) 324 { 325 struct erofs_map_blocks map = { 326 .m_la = iblock << 9, 327 }; 328 int err; 329 330 err = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW); 331 if (err) 332 return err; 333 334 if (map.m_flags & EROFS_MAP_MAPPED) 335 bh->b_blocknr = erofs_blknr(map.m_pa); 336 337 return err; 338 } 339 340 static sector_t erofs_bmap(struct address_space *mapping, sector_t block) 341 { 342 struct inode *inode = mapping->host; 343 344 if (EROFS_I(inode)->datalayout == EROFS_INODE_FLAT_INLINE) { 345 erofs_blk_t blks = i_size_read(inode) >> LOG_BLOCK_SIZE; 346 347 if (block >> LOG_SECTORS_PER_BLOCK >= blks) 348 return 0; 349 } 350 351 return generic_block_bmap(mapping, block, erofs_get_block); 352 } 353 354 /* for uncompressed (aligned) files and raw access for other files */ 355 const struct address_space_operations erofs_raw_access_aops = { 356 .readpage = erofs_raw_access_readpage, 357 .readpages = erofs_raw_access_readpages, 358 .bmap = erofs_bmap, 359 }; 360 361