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