Commit c665b394 authored by Jeffle Xu's avatar Jeffle Xu Committed by Gao Xiang
Browse files

erofs: implement fscache-based data readahead 



Implement fscache-based data readahead. Also registers an individual
bdi for each erofs instance to enable readahead.

Signed-off-by: default avatarJeffle Xu <jefflexu@linux.alibaba.com>
Reviewed-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220425122143.56815-21-jefflexu@linux.alibaba.com


Acked-by: default avatarChao Yu <chao@kernel.org>
Signed-off-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
parent bd735bda

fs/erofs/fscache.c

+90 −0
Original line number Diff line number Diff line
@@ -162,12 +162,102 @@ static int erofs_fscache_readpage(struct file *file, struct page *page) 
	return ret;

}



static void erofs_fscache_unlock_folios(struct readahead_control *rac,

					size_t len)

{

	while (len) {

		struct folio *folio = readahead_folio(rac);



		len -= folio_size(folio);

		folio_mark_uptodate(folio);

		folio_unlock(folio);

	}

}



static void erofs_fscache_readahead(struct readahead_control *rac)

{

	struct inode *inode = rac->mapping->host;

	struct super_block *sb = inode->i_sb;

	size_t len, count, done = 0;

	erofs_off_t pos;

	loff_t start, offset;

	int ret;



	if (!readahead_count(rac))

		return;



	start = readahead_pos(rac);

	len = readahead_length(rac);



	do {

		struct erofs_map_blocks map;

		struct erofs_map_dev mdev;



		pos = start + done;

		map.m_la = pos;



		ret = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);

		if (ret)

			return;



		offset = start + done;

		count = min_t(size_t, map.m_llen - (pos - map.m_la),

			      len - done);



		if (!(map.m_flags & EROFS_MAP_MAPPED)) {

			struct iov_iter iter;



			iov_iter_xarray(&iter, READ, &rac->mapping->i_pages,

					offset, count);

			iov_iter_zero(count, &iter);



			erofs_fscache_unlock_folios(rac, count);

			ret = count;

			continue;

		}



		if (map.m_flags & EROFS_MAP_META) {

			struct folio *folio = readahead_folio(rac);



			ret = erofs_fscache_readpage_inline(folio, &map);

			if (!ret) {

				folio_mark_uptodate(folio);

				ret = folio_size(folio);

			}



			folio_unlock(folio);

			continue;

		}



		mdev = (struct erofs_map_dev) {

			.m_deviceid = map.m_deviceid,

			.m_pa = map.m_pa,

		};

		ret = erofs_map_dev(sb, &mdev);

		if (ret)

			return;



		ret = erofs_fscache_read_folios(mdev.m_fscache->cookie,

				rac->mapping, offset, count,

				mdev.m_pa + (pos - map.m_la));

		/*

		 * For the error cases, the folios will be unlocked when

		 * .readahead() returns.

		 */

		if (!ret) {

			erofs_fscache_unlock_folios(rac, count);

			ret = count;

		}

	} while (ret > 0 && ((done += ret) < len));

}



static const struct address_space_operations erofs_fscache_meta_aops = {

	.readpage = erofs_fscache_meta_readpage,

};



const struct address_space_operations erofs_fscache_access_aops = {

	.readpage = erofs_fscache_readpage,

	.readahead = erofs_fscache_readahead,

};



int erofs_fscache_register_cookie(struct super_block *sb,

fs/erofs/super.c

+4 −0
Original line number Diff line number Diff line
@@ -658,6 +658,10 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc) 
						    sbi->opt.fsid, true);

		if (err)

			return err;



		err = super_setup_bdi(sb);

		if (err)

			return err;

	} else {

		if (!sb_set_blocksize(sb, EROFS_BLKSIZ)) {

			erofs_err(sb, "failed to set erofs blksize");