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staging: erofs: add raw address_space operations
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@huawei.com> Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Gao Xiang
Greg Kroah-Hartman
parent
ba2b77a820
commit
81781b02f9
362
drivers/staging/erofs/data.c
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362
drivers/staging/erofs/data.c
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@ -0,0 +1,362 @@
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// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/drivers/staging/erofs/data.c
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*
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* Copyright (C) 2017-2018 HUAWEI, Inc.
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* http://www.huawei.com/
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* Created by Gao Xiang <gaoxiang25@huawei.com>
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file COPYING in the main directory of the Linux
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* distribution for more details.
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*/
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#include "internal.h"
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#include <linux/prefetch.h>
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static inline void read_endio(struct bio *bio)
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{
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int i;
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struct bio_vec *bvec;
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const blk_status_t err = bio->bi_status;
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bio_for_each_segment_all(bvec, bio, i) {
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struct page *page = bvec->bv_page;
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/* page is already locked */
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BUG_ON(PageUptodate(page));
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if (unlikely(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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static void __submit_bio(struct bio *bio, unsigned op, unsigned op_flags)
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{
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bio_set_op_attrs(bio, op, op_flags);
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submit_bio(bio);
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}
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static struct bio *prepare_bio(struct super_block *sb,
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erofs_blk_t blkaddr, unsigned nr_pages)
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{
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struct bio *bio = bio_alloc(GFP_NOIO | __GFP_NOFAIL, nr_pages);
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BUG_ON(bio == NULL);
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bio->bi_end_io = read_endio;
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bio_set_dev(bio, sb->s_bdev);
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bio->bi_iter.bi_sector = blkaddr << LOG_SECTORS_PER_BLOCK;
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return bio;
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}
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/* prio -- true is used for dir */
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struct page *erofs_get_meta_page(struct super_block *sb,
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erofs_blk_t blkaddr, bool prio)
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{
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struct inode *bd_inode = sb->s_bdev->bd_inode;
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struct address_space *mapping = bd_inode->i_mapping;
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struct page *page;
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repeat:
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page = find_or_create_page(mapping, blkaddr,
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/*
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* Prefer looping in the allocator rather than here,
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* at least that code knows what it's doing.
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*/
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mapping_gfp_constraint(mapping, ~__GFP_FS) | __GFP_NOFAIL);
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BUG_ON(!page || !PageLocked(page));
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if (!PageUptodate(page)) {
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struct bio *bio;
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int err;
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bio = prepare_bio(sb, blkaddr, 1);
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err = bio_add_page(bio, page, PAGE_SIZE, 0);
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BUG_ON(err != PAGE_SIZE);
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__submit_bio(bio, REQ_OP_READ,
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REQ_META | (prio ? REQ_PRIO : 0));
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lock_page(page);
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/* the page has been truncated by others? */
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if (unlikely(page->mapping != mapping)) {
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unlock_page(page);
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put_page(page);
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goto repeat;
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}
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/* more likely a read error */
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if (unlikely(!PageUptodate(page))) {
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unlock_page(page);
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put_page(page);
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page = ERR_PTR(-EIO);
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}
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}
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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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erofs_blk_t nblocks, lastblk;
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u64 offset = map->m_la;
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struct erofs_vnode *vi = EROFS_V(inode);
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BUG_ON(is_inode_layout_compression(inode));
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nblocks = DIV_ROUND_UP(inode->i_size, PAGE_SIZE);
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lastblk = nblocks - is_inode_layout_inline(inode);
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if (unlikely(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 (is_inode_layout_inline(inode)) {
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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 locate in one meta block */
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BUG_ON(erofs_blkoff(map->m_pa) + map->m_plen > PAGE_SIZE);
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map->m_flags |= EROFS_MAP_META;
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} else {
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errln("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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BUG();
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}
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out:
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map->m_llen = map->m_plen;
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debugln("%s, m_la 0x%llx m_pa %llx m_len %llu",
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__func__, map->m_la, map->m_pa, map->m_plen);
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return 0;
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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 (unlikely(is_inode_layout_compression(inode)))
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return -ENOTSUPP;
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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(
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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 nblocks,
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bool ra)
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{
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struct inode *inode = mapping->host;
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erofs_off_t current_block = (erofs_off_t)page->index;
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int err;
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BUG_ON(!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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if (cleancache_get_page(page) == 0) {
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err = 0;
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SetPageUptodate(page);
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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 != NULL &&
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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, REQ_OP_READ, 0);
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bio = NULL;
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}
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if (bio == NULL) {
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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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err = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);
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if (unlikely(err))
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goto err_out;
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/* zero out the holed page */
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if (unlikely(!(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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BUG_ON(map.m_plen != map.m_llen);
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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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BUG_ON(map.m_plen > PAGE_SIZE);
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ipage = erofs_get_meta_page(inode->i_sb,
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erofs_blknr(map.m_pa), 0);
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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 + erofs_blkoff(map.m_pa), 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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BUG_ON(erofs_blkoff(map.m_pa) != 0);
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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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if (nblocks > BIO_MAX_PAGES)
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nblocks = BIO_MAX_PAGES;
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bio = prepare_bio(inode->i_sb, erofs_blknr(map.m_pa), nblocks);
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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 (unlikely(bio->bi_vcnt >= bio->bi_max_vecs)) {
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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 != NULL)
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submit_bio_out:
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__submit_bio(bio, REQ_OP_READ, 0);
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return unlikely(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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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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BUG_ON(bio != NULL); /* since we have only one bio -- must be NULL */
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return 0;
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}
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static int erofs_raw_access_readpages(struct file *filp,
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struct address_space *mapping,
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struct list_head *pages, unsigned nr_pages)
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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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gfp_t gfp = readahead_gfp_mask(mapping);
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for (; nr_pages; --nr_pages) {
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struct page *page = list_entry(pages->prev, struct page, lru);
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prefetchw(&page->flags);
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list_del(&page->lru);
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if (!add_to_page_cache_lru(page, mapping, page->index, gfp)) {
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bio = erofs_read_raw_page(bio, mapping, page,
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&last_block, nr_pages, 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_V(mapping->host)->nid);
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bio = NULL;
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}
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}
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/* pages could still be locked */
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put_page(page);
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}
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BUG_ON(!list_empty(pages));
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/* the rare case (end in gaps) */
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if (unlikely(bio != NULL))
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__submit_bio(bio, REQ_OP_READ, 0);
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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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.readpages = erofs_raw_access_readpages,
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};
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