linux-stable/fs/erofs/data.c
Gao Xiang 618f40ea02 erofs: use read_cache_page_gfp for erofs_get_meta_page
As Christoph said [1], "I'd much prefer to just use
read_cache_page_gfp, and live with the fact that this
allocates bufferheads behind you for now.  I'll try to
speed up my attempts to get rid of the buffer heads on
the block device mapping instead. "

This simplifies the code a lot and a minor thing is
"no REQ_META (e.g. for blktrace) on metadata at all..."

[1] https://lore.kernel.org/r/20190903153704.GA2201@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Link: https://lore.kernel.org/r/20190904020912.63925-26-gaoxiang25@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-05 20:10:09 +02:00

360 lines
8.5 KiB
C

// 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 inode *const bd_inode = sb->s_bdev->bd_inode;
struct address_space *const mapping = bd_inode->i_mapping;
return read_cache_page_gfp(mapping, blkaddr,
mapping_gfp_constraint(mapping, ~__GFP_FS));
}
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,
};