// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2017-2018 HUAWEI, Inc. * http://www.huawei.com/ * Created by Gao Xiang <gaoxiang25@huawei.com> */ #include "internal.h" #include <linux/prefetch.h> #include <trace/events/erofs.h> static void erofs_readendio(struct bio *bio) { struct bio_vec *bvec; blk_status_t err = bio->bi_status; struct bvec_iter_all iter_all; bio_for_each_segment_all(bvec, bio, iter_all) { struct page *page = bvec->bv_page; /* page is already locked */ DBG_BUGON(PageUptodate(page)); if (err) SetPageError(page); else SetPageUptodate(page); unlock_page(page); /* page could be reclaimed now */ } bio_put(bio); } struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr) { struct address_space *const mapping = sb->s_bdev->bd_inode->i_mapping; struct page *page; page = read_cache_page_gfp(mapping, blkaddr, mapping_gfp_constraint(mapping, ~__GFP_FS)); /* should already be PageUptodate */ if (!IS_ERR(page)) lock_page(page); return page; } static int erofs_map_blocks_flatmode(struct inode *inode, struct erofs_map_blocks *map, int flags) { int err = 0; erofs_blk_t nblocks, lastblk; u64 offset = map->m_la; struct erofs_inode *vi = EROFS_I(inode); bool tailendpacking = (vi->datalayout == EROFS_INODE_FLAT_INLINE); trace_erofs_map_blocks_flatmode_enter(inode, map, flags); nblocks = DIV_ROUND_UP(inode->i_size, PAGE_SIZE); lastblk = nblocks - tailendpacking; if (offset >= inode->i_size) { /* leave out-of-bound access unmapped */ map->m_flags = 0; map->m_plen = 0; goto out; } /* there is no hole in flatmode */ map->m_flags = EROFS_MAP_MAPPED; if (offset < blknr_to_addr(lastblk)) { map->m_pa = blknr_to_addr(vi->raw_blkaddr) + map->m_la; map->m_plen = blknr_to_addr(lastblk) - offset; } else if (tailendpacking) { /* 2 - inode inline B: inode, [xattrs], inline last blk... */ struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb); map->m_pa = iloc(sbi, vi->nid) + vi->inode_isize + vi->xattr_isize + erofs_blkoff(map->m_la); map->m_plen = inode->i_size - offset; /* inline data should be located in one meta block */ if (erofs_blkoff(map->m_pa) + map->m_plen > PAGE_SIZE) { erofs_err(inode->i_sb, "inline data cross block boundary @ nid %llu", vi->nid); DBG_BUGON(1); err = -EFSCORRUPTED; goto err_out; } map->m_flags |= EROFS_MAP_META; } else { erofs_err(inode->i_sb, "internal error @ nid: %llu (size %llu), m_la 0x%llx", vi->nid, inode->i_size, map->m_la); DBG_BUGON(1); err = -EIO; goto err_out; } out: map->m_llen = map->m_plen; err_out: trace_erofs_map_blocks_flatmode_exit(inode, map, flags, 0); return err; } int erofs_map_blocks(struct inode *inode, struct erofs_map_blocks *map, int flags) { if (erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout)) { int err = z_erofs_map_blocks_iter(inode, map, flags); if (map->mpage) { put_page(map->mpage); map->mpage = NULL; } return err; } return erofs_map_blocks_flatmode(inode, map, flags); } static inline struct bio *erofs_read_raw_page(struct bio *bio, struct address_space *mapping, struct page *page, erofs_off_t *last_block, unsigned int nblocks, bool ra) { struct inode *const inode = mapping->host; struct super_block *const sb = inode->i_sb; erofs_off_t current_block = (erofs_off_t)page->index; int err; DBG_BUGON(!nblocks); if (PageUptodate(page)) { err = 0; goto has_updated; } /* note that for readpage case, bio also equals to NULL */ if (bio && /* not continuous */ *last_block + 1 != current_block) { submit_bio_retry: submit_bio(bio); bio = NULL; } if (!bio) { struct erofs_map_blocks map = { .m_la = blknr_to_addr(current_block), }; erofs_blk_t blknr; unsigned int blkoff; err = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW); if (err) goto err_out; /* zero out the holed page */ if (!(map.m_flags & EROFS_MAP_MAPPED)) { zero_user_segment(page, 0, PAGE_SIZE); SetPageUptodate(page); /* imply err = 0, see erofs_map_blocks */ goto has_updated; } /* for RAW access mode, m_plen must be equal to m_llen */ DBG_BUGON(map.m_plen != map.m_llen); blknr = erofs_blknr(map.m_pa); blkoff = erofs_blkoff(map.m_pa); /* deal with inline page */ if (map.m_flags & EROFS_MAP_META) { void *vsrc, *vto; struct page *ipage; DBG_BUGON(map.m_plen > PAGE_SIZE); ipage = erofs_get_meta_page(inode->i_sb, blknr); if (IS_ERR(ipage)) { err = PTR_ERR(ipage); goto err_out; } vsrc = kmap_atomic(ipage); vto = kmap_atomic(page); memcpy(vto, vsrc + blkoff, map.m_plen); memset(vto + map.m_plen, 0, PAGE_SIZE - map.m_plen); kunmap_atomic(vto); kunmap_atomic(vsrc); flush_dcache_page(page); SetPageUptodate(page); /* TODO: could we unlock the page earlier? */ unlock_page(ipage); put_page(ipage); /* imply err = 0, see erofs_map_blocks */ goto has_updated; } /* pa must be block-aligned for raw reading */ DBG_BUGON(erofs_blkoff(map.m_pa)); /* max # of continuous pages */ if (nblocks > DIV_ROUND_UP(map.m_plen, PAGE_SIZE)) nblocks = DIV_ROUND_UP(map.m_plen, PAGE_SIZE); if (nblocks > BIO_MAX_PAGES) nblocks = BIO_MAX_PAGES; bio = bio_alloc(GFP_NOIO, nblocks); bio->bi_end_io = erofs_readendio; bio_set_dev(bio, sb->s_bdev); bio->bi_iter.bi_sector = (sector_t)blknr << LOG_SECTORS_PER_BLOCK; bio->bi_opf = REQ_OP_READ; } err = bio_add_page(bio, page, PAGE_SIZE, 0); /* out of the extent or bio is full */ if (err < PAGE_SIZE) goto submit_bio_retry; *last_block = current_block; /* shift in advance in case of it followed by too many gaps */ if (bio->bi_iter.bi_size >= bio->bi_max_vecs * PAGE_SIZE) { /* err should reassign to 0 after submitting */ err = 0; goto submit_bio_out; } return bio; err_out: /* for sync reading, set page error immediately */ if (!ra) { SetPageError(page); ClearPageUptodate(page); } has_updated: unlock_page(page); /* if updated manually, continuous pages has a gap */ if (bio) submit_bio_out: submit_bio(bio); return err ? ERR_PTR(err) : NULL; } /* * since we dont have write or truncate flows, so no inode * locking needs to be held at the moment. */ static int erofs_raw_access_readpage(struct file *file, struct page *page) { erofs_off_t last_block; struct bio *bio; trace_erofs_readpage(page, true); bio = erofs_read_raw_page(NULL, page->mapping, page, &last_block, 1, false); if (IS_ERR(bio)) return PTR_ERR(bio); DBG_BUGON(bio); /* since we have only one bio -- must be NULL */ return 0; } static int erofs_raw_access_readpages(struct file *filp, struct address_space *mapping, struct list_head *pages, unsigned int nr_pages) { erofs_off_t last_block; struct bio *bio = NULL; gfp_t gfp = readahead_gfp_mask(mapping); struct page *page = list_last_entry(pages, struct page, lru); trace_erofs_readpages(mapping->host, page, nr_pages, true); for (; nr_pages; --nr_pages) { page = list_entry(pages->prev, struct page, lru); prefetchw(&page->flags); list_del(&page->lru); if (!add_to_page_cache_lru(page, mapping, page->index, gfp)) { bio = erofs_read_raw_page(bio, mapping, page, &last_block, nr_pages, true); /* all the page errors are ignored when readahead */ if (IS_ERR(bio)) { pr_err("%s, readahead error at page %lu of nid %llu\n", __func__, page->index, EROFS_I(mapping->host)->nid); bio = NULL; } } /* pages could still be locked */ put_page(page); } DBG_BUGON(!list_empty(pages)); /* the rare case (end in gaps) */ if (bio) submit_bio(bio); return 0; } static int erofs_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh, int create) { struct erofs_map_blocks map = { .m_la = iblock << 9, }; int err; err = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW); if (err) return err; if (map.m_flags & EROFS_MAP_MAPPED) bh->b_blocknr = erofs_blknr(map.m_pa); return err; } static sector_t erofs_bmap(struct address_space *mapping, sector_t block) { struct inode *inode = mapping->host; if (EROFS_I(inode)->datalayout == EROFS_INODE_FLAT_INLINE) { erofs_blk_t blks = i_size_read(inode) >> LOG_BLOCK_SIZE; if (block >> LOG_SECTORS_PER_BLOCK >= blks) return 0; } return generic_block_bmap(mapping, block, erofs_get_block); } /* for uncompressed (aligned) files and raw access for other files */ const struct address_space_operations erofs_raw_access_aops = { .readpage = erofs_raw_access_readpage, .readpages = erofs_raw_access_readpages, .bmap = erofs_bmap, };