1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2017-2018 HUAWEI, Inc.
4 * http://www.huawei.com/
5 * Created by Gao Xiang <gaoxiang25@huawei.com>
8 #include <linux/prefetch.h>
10 #include <trace/events/erofs.h>
12 static inline void read_endio(struct bio *bio)
14 struct super_block *const sb = bio->bi_private;
16 blk_status_t err = bio->bi_status;
17 struct bvec_iter_all iter_all;
19 if (time_to_inject(EROFS_SB(sb), FAULT_READ_IO)) {
20 erofs_show_injection_info(FAULT_READ_IO);
24 bio_for_each_segment_all(bvec, bio, iter_all) {
25 struct page *page = bvec->bv_page;
27 /* page is already locked */
28 DBG_BUGON(PageUptodate(page));
33 SetPageUptodate(page);
36 /* page could be reclaimed now */
41 static struct bio *erofs_grab_raw_bio(struct super_block *sb,
43 unsigned int nr_pages,
46 struct bio *bio = bio_alloc(GFP_NOIO, nr_pages);
48 bio->bi_end_io = read_endio;
49 bio_set_dev(bio, sb->s_bdev);
50 bio->bi_iter.bi_sector = (sector_t)blkaddr << LOG_SECTORS_PER_BLOCK;
53 bio->bi_opf = REQ_OP_READ | REQ_META;
55 bio->bi_opf = REQ_OP_READ;
60 struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr)
62 struct inode *const bd_inode = sb->s_bdev->bd_inode;
63 struct address_space *const mapping = bd_inode->i_mapping;
64 const gfp_t gfp = mapping_gfp_constraint(mapping, ~__GFP_FS);
69 page = find_or_create_page(mapping, blkaddr, gfp);
71 return ERR_PTR(-ENOMEM);
73 DBG_BUGON(!PageLocked(page));
75 if (!PageUptodate(page)) {
78 bio = erofs_grab_raw_bio(sb, blkaddr, 1, true);
80 if (bio_add_page(bio, page, PAGE_SIZE, 0) != PAGE_SIZE) {
88 /* this page has been truncated by others */
89 if (page->mapping != mapping) {
95 /* more likely a read error */
96 if (!PageUptodate(page)) {
109 static int erofs_map_blocks_flatmode(struct inode *inode,
110 struct erofs_map_blocks *map,
114 erofs_blk_t nblocks, lastblk;
115 u64 offset = map->m_la;
116 struct erofs_inode *vi = EROFS_I(inode);
117 bool tailendpacking = (vi->datalayout == EROFS_INODE_FLAT_INLINE);
119 trace_erofs_map_blocks_flatmode_enter(inode, map, flags);
121 nblocks = DIV_ROUND_UP(inode->i_size, PAGE_SIZE);
122 lastblk = nblocks - tailendpacking;
124 if (offset >= inode->i_size) {
125 /* leave out-of-bound access unmapped */
131 /* there is no hole in flatmode */
132 map->m_flags = EROFS_MAP_MAPPED;
134 if (offset < blknr_to_addr(lastblk)) {
135 map->m_pa = blknr_to_addr(vi->raw_blkaddr) + map->m_la;
136 map->m_plen = blknr_to_addr(lastblk) - offset;
137 } else if (tailendpacking) {
138 /* 2 - inode inline B: inode, [xattrs], inline last blk... */
139 struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
141 map->m_pa = iloc(sbi, vi->nid) + vi->inode_isize +
142 vi->xattr_isize + erofs_blkoff(map->m_la);
143 map->m_plen = inode->i_size - offset;
145 /* inline data should be located in one meta block */
146 if (erofs_blkoff(map->m_pa) + map->m_plen > PAGE_SIZE) {
147 errln("inline data cross block boundary @ nid %llu",
154 map->m_flags |= EROFS_MAP_META;
156 errln("internal error @ nid: %llu (size %llu), m_la 0x%llx",
157 vi->nid, inode->i_size, map->m_la);
164 map->m_llen = map->m_plen;
167 trace_erofs_map_blocks_flatmode_exit(inode, map, flags, 0);
171 int erofs_map_blocks(struct inode *inode,
172 struct erofs_map_blocks *map, int flags)
174 if (erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout)) {
175 int err = z_erofs_map_blocks_iter(inode, map, flags);
178 put_page(map->mpage);
183 return erofs_map_blocks_flatmode(inode, map, flags);
186 static inline struct bio *erofs_read_raw_page(struct bio *bio,
187 struct address_space *mapping,
189 erofs_off_t *last_block,
190 unsigned int nblocks,
193 struct inode *const inode = mapping->host;
194 struct super_block *const sb = inode->i_sb;
195 erofs_off_t current_block = (erofs_off_t)page->index;
200 if (PageUptodate(page)) {
205 /* note that for readpage case, bio also equals to NULL */
208 *last_block + 1 != current_block) {
215 struct erofs_map_blocks map = {
216 .m_la = blknr_to_addr(current_block),
221 err = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);
225 /* zero out the holed page */
226 if (!(map.m_flags & EROFS_MAP_MAPPED)) {
227 zero_user_segment(page, 0, PAGE_SIZE);
228 SetPageUptodate(page);
230 /* imply err = 0, see erofs_map_blocks */
234 /* for RAW access mode, m_plen must be equal to m_llen */
235 DBG_BUGON(map.m_plen != map.m_llen);
237 blknr = erofs_blknr(map.m_pa);
238 blkoff = erofs_blkoff(map.m_pa);
240 /* deal with inline page */
241 if (map.m_flags & EROFS_MAP_META) {
245 DBG_BUGON(map.m_plen > PAGE_SIZE);
247 ipage = erofs_get_meta_page(inode->i_sb, blknr);
250 err = PTR_ERR(ipage);
254 vsrc = kmap_atomic(ipage);
255 vto = kmap_atomic(page);
256 memcpy(vto, vsrc + blkoff, map.m_plen);
257 memset(vto + map.m_plen, 0, PAGE_SIZE - map.m_plen);
260 flush_dcache_page(page);
262 SetPageUptodate(page);
263 /* TODO: could we unlock the page earlier? */
267 /* imply err = 0, see erofs_map_blocks */
271 /* pa must be block-aligned for raw reading */
272 DBG_BUGON(erofs_blkoff(map.m_pa));
274 /* max # of continuous pages */
275 if (nblocks > DIV_ROUND_UP(map.m_plen, PAGE_SIZE))
276 nblocks = DIV_ROUND_UP(map.m_plen, PAGE_SIZE);
277 if (nblocks > BIO_MAX_PAGES)
278 nblocks = BIO_MAX_PAGES;
280 bio = erofs_grab_raw_bio(sb, blknr, nblocks, false);
283 err = bio_add_page(bio, page, PAGE_SIZE, 0);
284 /* out of the extent or bio is full */
286 goto submit_bio_retry;
288 *last_block = current_block;
290 /* shift in advance in case of it followed by too many gaps */
291 if (bio->bi_iter.bi_size >= bio->bi_max_vecs * PAGE_SIZE) {
292 /* err should reassign to 0 after submitting */
300 /* for sync reading, set page error immediately */
303 ClearPageUptodate(page);
308 /* if updated manually, continuous pages has a gap */
312 return err ? ERR_PTR(err) : NULL;
316 * since we dont have write or truncate flows, so no inode
317 * locking needs to be held at the moment.
319 static int erofs_raw_access_readpage(struct file *file, struct page *page)
321 erofs_off_t last_block;
324 trace_erofs_readpage(page, true);
326 bio = erofs_read_raw_page(NULL, page->mapping,
327 page, &last_block, 1, false);
332 DBG_BUGON(bio); /* since we have only one bio -- must be NULL */
336 static int erofs_raw_access_readpages(struct file *filp,
337 struct address_space *mapping,
338 struct list_head *pages,
339 unsigned int nr_pages)
341 erofs_off_t last_block;
342 struct bio *bio = NULL;
343 gfp_t gfp = readahead_gfp_mask(mapping);
344 struct page *page = list_last_entry(pages, struct page, lru);
346 trace_erofs_readpages(mapping->host, page, nr_pages, true);
348 for (; nr_pages; --nr_pages) {
349 page = list_entry(pages->prev, struct page, lru);
351 prefetchw(&page->flags);
352 list_del(&page->lru);
354 if (!add_to_page_cache_lru(page, mapping, page->index, gfp)) {
355 bio = erofs_read_raw_page(bio, mapping, page,
356 &last_block, nr_pages, true);
358 /* all the page errors are ignored when readahead */
360 pr_err("%s, readahead error at page %lu of nid %llu\n",
361 __func__, page->index,
362 EROFS_I(mapping->host)->nid);
368 /* pages could still be locked */
371 DBG_BUGON(!list_empty(pages));
373 /* the rare case (end in gaps) */
379 static int erofs_get_block(struct inode *inode, sector_t iblock,
380 struct buffer_head *bh, int create)
382 struct erofs_map_blocks map = {
387 err = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);
391 if (map.m_flags & EROFS_MAP_MAPPED)
392 bh->b_blocknr = erofs_blknr(map.m_pa);
397 static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
399 struct inode *inode = mapping->host;
401 if (EROFS_I(inode)->datalayout == EROFS_INODE_FLAT_INLINE) {
402 erofs_blk_t blks = i_size_read(inode) >> LOG_BLOCK_SIZE;
404 if (block >> LOG_SECTORS_PER_BLOCK >= blks)
408 return generic_block_bmap(mapping, block, erofs_get_block);
411 /* for uncompressed (aligned) files and raw access for other files */
412 const struct address_space_operations erofs_raw_access_aops = {
413 .readpage = erofs_raw_access_readpage,
414 .readpages = erofs_raw_access_readpages,