This commit adds functions for meta and raw data, and also provides address_space_operations for raw data access. Signed-off-by: Miao Xie <miaoxie@xxxxxxxxxx> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx> Signed-off-by: Gao Xiang <gaoxiang25@xxxxxxxxxx> --- drivers/staging/erofs/data.c | 362 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 362 insertions(+) create mode 100644 drivers/staging/erofs/data.c diff --git a/drivers/staging/erofs/data.c b/drivers/staging/erofs/data.c new file mode 100644 index 0000000..4ddb5c0 --- /dev/null +++ b/drivers/staging/erofs/data.c @@ -0,0 +1,362 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/drivers/staging/erofs/data.c + * + * Copyright (C) 2017-2018 HUAWEI, Inc. + * http://www.huawei.com/ + * Created by Gao Xiang <gaoxiang25@xxxxxxxxxx> + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file COPYING in the main directory of the Linux + * distribution for more details. + */ +#include "internal.h" +#include <linux/prefetch.h> + +static inline void read_endio(struct bio *bio) +{ + int i; + struct bio_vec *bvec; + const blk_status_t err = bio->bi_status; + + bio_for_each_segment_all(bvec, bio, i) { + struct page *page = bvec->bv_page; + + /* page is already locked */ + BUG_ON(PageUptodate(page)); + + if (unlikely(err)) + SetPageError(page); + else + SetPageUptodate(page); + + unlock_page(page); + /* page could be reclaimed now */ + } + bio_put(bio); +} + +static void __submit_bio(struct bio *bio, unsigned op, unsigned op_flags) +{ + bio_set_op_attrs(bio, op, op_flags); + submit_bio(bio); +} + +static struct bio *prepare_bio(struct super_block *sb, + erofs_blk_t blkaddr, unsigned nr_pages) +{ + struct bio *bio = bio_alloc(GFP_NOIO | __GFP_NOFAIL, nr_pages); + + BUG_ON(bio == NULL); + + bio->bi_end_io = read_endio; + bio_set_dev(bio, sb->s_bdev); + bio->bi_iter.bi_sector = blkaddr << LOG_SECTORS_PER_BLOCK; + + return bio; +} + +/* prio -- true is used for dir */ +struct page *erofs_get_meta_page(struct super_block *sb, + erofs_blk_t blkaddr, bool prio) +{ + struct inode *bd_inode = sb->s_bdev->bd_inode; + struct address_space *mapping = bd_inode->i_mapping; + struct page *page; + +repeat: + page = find_or_create_page(mapping, blkaddr, + /* + * Prefer looping in the allocator rather than here, + * at least that code knows what it's doing. + */ + mapping_gfp_constraint(mapping, ~__GFP_FS) | __GFP_NOFAIL); + + BUG_ON(!page || !PageLocked(page)); + + if (!PageUptodate(page)) { + struct bio *bio; + int err; + + bio = prepare_bio(sb, blkaddr, 1); + err = bio_add_page(bio, page, PAGE_SIZE, 0); + BUG_ON(err != PAGE_SIZE); + + __submit_bio(bio, REQ_OP_READ, + REQ_META | (prio ? REQ_PRIO : 0)); + + lock_page(page); + + /* the page has been truncated by others? */ + if (unlikely(page->mapping != mapping)) { + unlock_page(page); + put_page(page); + goto repeat; + } + + /* more likely a read error */ + if (unlikely(!PageUptodate(page))) { + unlock_page(page); + put_page(page); + + page = ERR_PTR(-EIO); + } + } + return page; +} + +static int erofs_map_blocks_flatmode(struct inode *inode, + struct erofs_map_blocks *map, + int flags) +{ + erofs_blk_t nblocks, lastblk; + u64 offset = map->m_la; + struct erofs_vnode *vi = EROFS_V(inode); + + BUG_ON(is_inode_layout_compression(inode)); + + nblocks = DIV_ROUND_UP(inode->i_size, PAGE_SIZE); + lastblk = nblocks - is_inode_layout_inline(inode); + + if (unlikely(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 (is_inode_layout_inline(inode)) { + /* 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 locate in one meta block */ + BUG_ON(erofs_blkoff(map->m_pa) + map->m_plen > PAGE_SIZE); + map->m_flags |= EROFS_MAP_META; + } else { + errln("internal error @ nid: %llu (size %llu), m_la 0x%llx", + vi->nid, inode->i_size, map->m_la); + BUG(); + } + +out: + map->m_llen = map->m_plen; + debugln("%s, m_la 0x%llx m_pa %llx m_len %llu", + __func__, map->m_la, map->m_pa, map->m_plen); + return 0; +} + +int erofs_map_blocks(struct inode *inode, + struct erofs_map_blocks *map, int flags) +{ + if (unlikely(is_inode_layout_compression(inode))) + return -ENOTSUPP; + + 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 nblocks, + bool ra) +{ + struct inode *inode = mapping->host; + erofs_off_t current_block = (erofs_off_t)page->index; + int err; + + BUG_ON(!nblocks); + + if (PageUptodate(page)) { + err = 0; + goto has_updated; + } + + if (cleancache_get_page(page) == 0) { + err = 0; + SetPageUptodate(page); + goto has_updated; + } + + /* note that for readpage case, bio also equals to NULL */ + if (bio != NULL && + /* not continuous */ + *last_block + 1 != current_block) { +submit_bio_retry: + __submit_bio(bio, REQ_OP_READ, 0); + bio = NULL; + } + + if (bio == NULL) { + struct erofs_map_blocks map = { + .m_la = blknr_to_addr(current_block), + }; + + err = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW); + if (unlikely(err)) + goto err_out; + + /* zero out the holed page */ + if (unlikely(!(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 */ + BUG_ON(map.m_plen != map.m_llen); + + /* deal with inline page */ + if (map.m_flags & EROFS_MAP_META) { + void *vsrc, *vto; + struct page *ipage; + + BUG_ON(map.m_plen > PAGE_SIZE); + + ipage = erofs_get_meta_page(inode->i_sb, + erofs_blknr(map.m_pa), 0); + + if (IS_ERR(ipage)) { + err = PTR_ERR(ipage); + goto err_out; + } + + vsrc = kmap_atomic(ipage); + vto = kmap_atomic(page); + memcpy(vto, vsrc + erofs_blkoff(map.m_pa), 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 */ + BUG_ON(erofs_blkoff(map.m_pa) != 0); + + /* 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 = prepare_bio(inode->i_sb, erofs_blknr(map.m_pa), nblocks); + } + + 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 (unlikely(bio->bi_vcnt >= bio->bi_max_vecs)) { + /* 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 != NULL) +submit_bio_out: + __submit_bio(bio, REQ_OP_READ, 0); + + return unlikely(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; + + bio = erofs_read_raw_page(NULL, page->mapping, + page, &last_block, 1, false); + + if (IS_ERR(bio)) + return PTR_ERR(bio); + + BUG_ON(bio != NULL); /* 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 nr_pages) +{ + erofs_off_t last_block; + struct bio *bio = NULL; + gfp_t gfp = readahead_gfp_mask(mapping); + + for (; nr_pages; --nr_pages) { + struct page *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_V(mapping->host)->nid); + + bio = NULL; + } + } + + /* pages could still be locked */ + put_page(page); + } + BUG_ON(!list_empty(pages)); + + /* the rare case (end in gaps) */ + if (unlikely(bio != NULL)) + __submit_bio(bio, REQ_OP_READ, 0); + return 0; +} + +/* 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, +}; + -- 1.9.1 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
