Commit fe5de585 authored by Gao Xiang's avatar Gao Xiang
Browse files

erofs: use meta buffers for reading directories 

Previously, directory inodes are directly handled with page cache
interfaces.

In order to support sub-page directory blocks and folios, let's
convert them into the latest metabuf infrastructure as well and
this patch addresses the readdir case first.

Link: https://lore.kernel.org/r/20220316012246.95131-1-hsiangkao@linux.alibaba.com


Reviewed-by: default avatarChao Yu <chao@kernel.org>
Signed-off-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
parent a942da24

fs/erofs/data.c

+9 −3
Original line number Diff line number Diff line
@@ -28,10 +28,10 @@ void erofs_put_metabuf(struct erofs_buf *buf) 
	buf->page = NULL;

}



void *erofs_read_metabuf(struct erofs_buf *buf, struct super_block *sb,

void *erofs_bread(struct erofs_buf *buf, struct inode *inode,

		  erofs_blk_t blkaddr, enum erofs_kmap_type type)

{

	struct address_space *const mapping = sb->s_bdev->bd_inode->i_mapping;

	struct address_space *const mapping = inode->i_mapping;

	erofs_off_t offset = blknr_to_addr(blkaddr);

	pgoff_t index = offset >> PAGE_SHIFT;

	struct page *page = buf->page;
@@ -60,6 +60,12 @@ void *erofs_read_metabuf(struct erofs_buf *buf, struct super_block *sb, 
	return buf->base + (offset & ~PAGE_MASK);

}



void *erofs_read_metabuf(struct erofs_buf *buf, struct super_block *sb,

			 erofs_blk_t blkaddr, enum erofs_kmap_type type)

{

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

}



static int erofs_map_blocks_flatmode(struct inode *inode,

				     struct erofs_map_blocks *map,

				     int flags)

fs/erofs/dir.c

+6 −15
Original line number Diff line number Diff line
@@ -2,6 +2,7 @@ 
/*

 * Copyright (C) 2017-2018 HUAWEI, Inc.

 *             https://www.huawei.com/

 * Copyright (C) 2022, Alibaba Cloud

 */

#include "internal.h"
@@ -67,7 +68,7 @@ static int erofs_fill_dentries(struct inode *dir, struct dir_context *ctx, 
static int erofs_readdir(struct file *f, struct dir_context *ctx)

{

	struct inode *dir = file_inode(f);

	struct address_space *mapping = dir->i_mapping;

	struct erofs_buf buf = __EROFS_BUF_INITIALIZER;

	const size_t dirsize = i_size_read(dir);

	unsigned int i = ctx->pos / EROFS_BLKSIZ;

	unsigned int ofs = ctx->pos % EROFS_BLKSIZ;
@@ -75,26 +76,19 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx) 
	bool initial = true;



	while (ctx->pos < dirsize) {

		struct page *dentry_page;

		struct erofs_dirent *de;

		unsigned int nameoff, maxsize;



		dentry_page = read_mapping_page(mapping, i, NULL);

		if (dentry_page == ERR_PTR(-ENOMEM)) {

			err = -ENOMEM;

			break;

		} else if (IS_ERR(dentry_page)) {

		de = erofs_bread(&buf, dir, i, EROFS_KMAP);

		if (IS_ERR(de)) {

			erofs_err(dir->i_sb,

				  "fail to readdir of logical block %u of nid %llu",

				  i, EROFS_I(dir)->nid);

			err = -EFSCORRUPTED;

			err = PTR_ERR(de);

			break;

		}



		de = (struct erofs_dirent *)kmap(dentry_page);



		nameoff = le16_to_cpu(de->nameoff);



		if (nameoff < sizeof(struct erofs_dirent) ||

		    nameoff >= PAGE_SIZE) {

			erofs_err(dir->i_sb,
@@ -119,10 +113,6 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx) 
		err = erofs_fill_dentries(dir, ctx, de, &ofs,

					  nameoff, maxsize);

skip_this:

		kunmap(dentry_page);



		put_page(dentry_page);



		ctx->pos = blknr_to_addr(i) + ofs;



		if (err)
@@ -130,6 +120,7 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx) 
		++i;

		ofs = 0;

	}

	erofs_put_metabuf(&buf);

	return err < 0 ? err : 0;

}

fs/erofs/internal.h

+2 −0
Original line number Diff line number Diff line
@@ -479,6 +479,8 @@ struct erofs_map_dev { 
extern const struct file_operations erofs_file_fops;

void erofs_unmap_metabuf(struct erofs_buf *buf);

void erofs_put_metabuf(struct erofs_buf *buf);

void *erofs_bread(struct erofs_buf *buf, struct inode *inode,

		  erofs_blk_t blkaddr, enum erofs_kmap_type type);

void *erofs_read_metabuf(struct erofs_buf *buf, struct super_block *sb,

			 erofs_blk_t blkaddr, enum erofs_kmap_type type);

int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *dev);