erofs: fix mis-inplace determination related with noio chain

Fix a recent cleanup patch. noio (bypass) chain is
handled asynchronously against submit chain, therefore
inplace I/O or pagevec cannot be applied to such pages.
Add detailed comment for this as well.

Fixes: 97e86a858b ("staging: erofs: tidy up decompression frontend")
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Link: https://lore.kernel.org/r/20190922100434.229340-1-gaoxiang25@huawei.com
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
This commit is contained in:
Gao Xiang 2019-09-22 18:04:34 +08:00
parent 55252ab72b
commit dc76ea8c10
1 changed files with 10 additions and 2 deletions

View File

@ -575,7 +575,7 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
struct erofs_map_blocks *const map = &fe->map;
struct z_erofs_collector *const clt = &fe->clt;
const loff_t offset = page_offset(page);
bool tight = (clt->mode >= COLLECT_PRIMARY_HOOKED);
bool tight = true;
enum z_erofs_cache_alloctype cache_strategy;
enum z_erofs_page_type page_type;
@ -628,8 +628,16 @@ restart_now:
preload_compressed_pages(clt, MNGD_MAPPING(sbi),
cache_strategy, pagepool);
tight &= (clt->mode >= COLLECT_PRIMARY_HOOKED);
hitted:
/*
* Ensure the current partial page belongs to this submit chain rather
* than other concurrent submit chains or the noio(bypass) chain since
* those chains are handled asynchronously thus the page cannot be used
* for inplace I/O or pagevec (should be processed in strict order.)
*/
tight &= (clt->mode >= COLLECT_PRIMARY_HOOKED &&
clt->mode != COLLECT_PRIMARY_FOLLOWED_NOINPLACE);
cur = end - min_t(unsigned int, offset + end - map->m_la, end);
if (!(map->m_flags & EROFS_MAP_MAPPED)) {
zero_user_segment(page, cur, end);