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 /* prio -- true is used for dir */
42 struct page *__erofs_get_meta_page(struct super_block *sb,
43 erofs_blk_t blkaddr, bool prio, bool nofail)
45 struct inode *const bd_inode = sb->s_bdev->bd_inode;
46 struct address_space *const mapping = bd_inode->i_mapping;
47 /* prefer retrying in the allocator to blindly looping below */
48 const gfp_t gfp = mapping_gfp_constraint(mapping, ~__GFP_FS) |
49 (nofail ? __GFP_NOFAIL : 0);
50 unsigned int io_retries = nofail ? EROFS_IO_MAX_RETRIES_NOFAIL : 0;
55 page = find_or_create_page(mapping, blkaddr, gfp);
56 if (unlikely(!page)) {
58 return ERR_PTR(-ENOMEM);
60 DBG_BUGON(!PageLocked(page));
62 if (!PageUptodate(page)) {
65 bio = erofs_grab_bio(sb, blkaddr, 1, sb, read_endio, nofail);
72 err = bio_add_page(bio, page, PAGE_SIZE, 0);
73 if (unlikely(err != PAGE_SIZE)) {
78 __submit_bio(bio, REQ_OP_READ,
79 REQ_META | (prio ? REQ_PRIO : 0));
83 /* this page has been truncated by others */
84 if (unlikely(page->mapping != mapping)) {
91 /* more likely a read error */
92 if (unlikely(!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_vnode *vi = EROFS_V(inode);
118 trace_erofs_map_blocks_flatmode_enter(inode, map, flags);
120 nblocks = DIV_ROUND_UP(inode->i_size, PAGE_SIZE);
121 lastblk = nblocks - is_inode_flat_inline(inode);
123 if (unlikely(offset >= inode->i_size)) {
124 /* leave out-of-bound access unmapped */
130 /* there is no hole in flatmode */
131 map->m_flags = EROFS_MAP_MAPPED;
133 if (offset < blknr_to_addr(lastblk)) {
134 map->m_pa = blknr_to_addr(vi->raw_blkaddr) + map->m_la;
135 map->m_plen = blknr_to_addr(lastblk) - offset;
136 } else if (is_inode_flat_inline(inode)) {
137 /* 2 - inode inline B: inode, [xattrs], inline last blk... */
138 struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
140 map->m_pa = iloc(sbi, vi->nid) + vi->inode_isize +
141 vi->xattr_isize + erofs_blkoff(map->m_la);
142 map->m_plen = inode->i_size - offset;
144 /* inline data should be located in one meta block */
145 if (erofs_blkoff(map->m_pa) + map->m_plen > PAGE_SIZE) {
146 errln("inline data cross block boundary @ nid %llu",
153 map->m_flags |= EROFS_MAP_META;
155 errln("internal error @ nid: %llu (size %llu), m_la 0x%llx",
156 vi->nid, inode->i_size, map->m_la);
163 map->m_llen = map->m_plen;
166 trace_erofs_map_blocks_flatmode_exit(inode, map, flags, 0);
170 int erofs_map_blocks(struct inode *inode,
171 struct erofs_map_blocks *map, int flags)
173 if (unlikely(is_inode_layout_compression(inode))) {
174 int err = z_erofs_map_blocks_iter(inode, map, flags);
177 put_page(map->mpage);
182 return erofs_map_blocks_flatmode(inode, map, flags);
185 static inline struct bio *erofs_read_raw_page(struct bio *bio,
186 struct address_space *mapping,
188 erofs_off_t *last_block,
189 unsigned int nblocks,
192 struct inode *const inode = mapping->host;
193 struct super_block *const sb = inode->i_sb;
194 erofs_off_t current_block = (erofs_off_t)page->index;
199 if (PageUptodate(page)) {
204 /* note that for readpage case, bio also equals to NULL */
207 *last_block + 1 != current_block) {
209 __submit_bio(bio, REQ_OP_READ, 0);
214 struct erofs_map_blocks map = {
215 .m_la = blknr_to_addr(current_block),
220 err = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);
224 /* zero out the holed page */
225 if (unlikely(!(map.m_flags & EROFS_MAP_MAPPED))) {
226 zero_user_segment(page, 0, PAGE_SIZE);
227 SetPageUptodate(page);
229 /* imply err = 0, see erofs_map_blocks */
233 /* for RAW access mode, m_plen must be equal to m_llen */
234 DBG_BUGON(map.m_plen != map.m_llen);
236 blknr = erofs_blknr(map.m_pa);
237 blkoff = erofs_blkoff(map.m_pa);
239 /* deal with inline page */
240 if (map.m_flags & EROFS_MAP_META) {
244 DBG_BUGON(map.m_plen > PAGE_SIZE);
246 ipage = erofs_get_meta_page(inode->i_sb, blknr, 0);
249 err = PTR_ERR(ipage);
253 vsrc = kmap_atomic(ipage);
254 vto = kmap_atomic(page);
255 memcpy(vto, vsrc + blkoff, map.m_plen);
256 memset(vto + map.m_plen, 0, PAGE_SIZE - map.m_plen);
259 flush_dcache_page(page);
261 SetPageUptodate(page);
262 /* TODO: could we unlock the page earlier? */
266 /* imply err = 0, see erofs_map_blocks */
270 /* pa must be block-aligned for raw reading */
271 DBG_BUGON(erofs_blkoff(map.m_pa));
273 /* max # of continuous pages */
274 if (nblocks > DIV_ROUND_UP(map.m_plen, PAGE_SIZE))
275 nblocks = DIV_ROUND_UP(map.m_plen, PAGE_SIZE);
276 if (nblocks > BIO_MAX_PAGES)
277 nblocks = BIO_MAX_PAGES;
279 bio = erofs_grab_bio(sb, blknr, nblocks, sb,
288 err = bio_add_page(bio, page, PAGE_SIZE, 0);
289 /* out of the extent or bio is full */
291 goto submit_bio_retry;
293 *last_block = current_block;
295 /* shift in advance in case of it followed by too many gaps */
296 if (bio->bi_iter.bi_size >= bio->bi_max_vecs * PAGE_SIZE) {
297 /* err should reassign to 0 after submitting */
305 /* for sync reading, set page error immediately */
308 ClearPageUptodate(page);
313 /* if updated manually, continuous pages has a gap */
316 __submit_bio(bio, REQ_OP_READ, 0);
318 return unlikely(err) ? ERR_PTR(err) : NULL;
322 * since we dont have write or truncate flows, so no inode
323 * locking needs to be held at the moment.
325 static int erofs_raw_access_readpage(struct file *file, struct page *page)
327 erofs_off_t last_block;
330 trace_erofs_readpage(page, true);
332 bio = erofs_read_raw_page(NULL, page->mapping,
333 page, &last_block, 1, false);
338 DBG_BUGON(bio); /* since we have only one bio -- must be NULL */
342 static int erofs_raw_access_readpages(struct file *filp,
343 struct address_space *mapping,
344 struct list_head *pages,
345 unsigned int nr_pages)
347 erofs_off_t last_block;
348 struct bio *bio = NULL;
349 gfp_t gfp = readahead_gfp_mask(mapping);
350 struct page *page = list_last_entry(pages, struct page, lru);
352 trace_erofs_readpages(mapping->host, page, nr_pages, true);
354 for (; nr_pages; --nr_pages) {
355 page = list_entry(pages->prev, struct page, lru);
357 prefetchw(&page->flags);
358 list_del(&page->lru);
360 if (!add_to_page_cache_lru(page, mapping, page->index, gfp)) {
361 bio = erofs_read_raw_page(bio, mapping, page,
362 &last_block, nr_pages, true);
364 /* all the page errors are ignored when readahead */
366 pr_err("%s, readahead error at page %lu of nid %llu\n",
367 __func__, page->index,
368 EROFS_V(mapping->host)->nid);
374 /* pages could still be locked */
377 DBG_BUGON(!list_empty(pages));
379 /* the rare case (end in gaps) */
381 __submit_bio(bio, REQ_OP_READ, 0);
385 static int erofs_get_block(struct inode *inode, sector_t iblock,
386 struct buffer_head *bh, int create)
388 struct erofs_map_blocks map = {
393 err = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);
397 if (map.m_flags & EROFS_MAP_MAPPED)
398 bh->b_blocknr = erofs_blknr(map.m_pa);
403 static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
405 struct inode *inode = mapping->host;
407 if (is_inode_flat_inline(inode)) {
408 erofs_blk_t blks = i_size_read(inode) >> LOG_BLOCK_SIZE;
410 if (block >> LOG_SECTORS_PER_BLOCK >= blks)
414 return generic_block_bmap(mapping, block, erofs_get_block);
417 /* for uncompressed (aligned) files and raw access for other files */
418 const struct address_space_operations erofs_raw_access_aops = {
419 .readpage = erofs_raw_access_readpage,
420 .readpages = erofs_raw_access_readpages,