Commit 5375e7c8 authored by Jeffle Xu's avatar Jeffle Xu Committed by Gao Xiang
Browse files

erofs: implement fscache-based metadata read 



Implement the data plane of reading metadata from primary data blob
over fscache.

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/20220425122143.56815-18-jefflexu@linux.alibaba.com


Acked-by: default avatarChao Yu <chao@kernel.org>
Signed-off-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
parent 955b478e

fs/erofs/data.c

+15 −4
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
 */

#include "internal.h"

#include <linux/prefetch.h>

#include <linux/sched/mm.h>

#include <linux/dax.h>

#include <trace/events/erofs.h>
@@ -35,14 +36,20 @@ void *erofs_bread(struct erofs_buf *buf, struct inode *inode, 
	erofs_off_t offset = blknr_to_addr(blkaddr);

	pgoff_t index = offset >> PAGE_SHIFT;

	struct page *page = buf->page;

	struct folio *folio;

	unsigned int nofs_flag;



	if (!page || page->index != index) {

		erofs_put_metabuf(buf);

		page = read_cache_page_gfp(mapping, index,

				mapping_gfp_constraint(mapping, ~__GFP_FS));

		if (IS_ERR(page))

			return page;



		nofs_flag = memalloc_nofs_save();

		folio = read_cache_folio(mapping, index, NULL, NULL);

		memalloc_nofs_restore(nofs_flag);

		if (IS_ERR(folio))

			return folio;



		/* should already be PageUptodate, no need to lock page */

		page = folio_file_page(folio, index);

		buf->page = page;

	}

	if (buf->kmap_type == EROFS_NO_KMAP) {
@@ -63,6 +70,10 @@ void *erofs_bread(struct erofs_buf *buf, struct inode *inode, 
void *erofs_read_metabuf(struct erofs_buf *buf, struct super_block *sb,

			 erofs_blk_t blkaddr, enum erofs_kmap_type type)

{

	if (erofs_is_fscache_mode(sb))

		return erofs_bread(buf, EROFS_SB(sb)->s_fscache->inode,

				   blkaddr, type);



	return erofs_bread(buf, sb->s_bdev->bd_inode, blkaddr, type);

}

fs/erofs/fscache.c

+25 −0
Original line number Diff line number Diff line
@@ -59,7 +59,32 @@ static int erofs_fscache_read_folios(struct fscache_cookie *cookie, 
	return ret;

}



static int erofs_fscache_meta_readpage(struct file *data, struct page *page)

{

	int ret;

	struct folio *folio = page_folio(page);

	struct super_block *sb = folio_mapping(folio)->host->i_sb;

	struct erofs_map_dev mdev = {

		.m_deviceid = 0,

		.m_pa = folio_pos(folio),

	};



	ret = erofs_map_dev(sb, &mdev);

	if (ret)

		goto out;



	ret = erofs_fscache_read_folios(mdev.m_fscache->cookie,

			folio_mapping(folio), folio_pos(folio),

			folio_size(folio), mdev.m_pa);

	if (!ret)

		folio_mark_uptodate(folio);

out:

	folio_unlock(folio);

	return ret;

}



static const struct address_space_operations erofs_fscache_meta_aops = {

	.readpage = erofs_fscache_meta_readpage,

};



int erofs_fscache_register_cookie(struct super_block *sb,