Commit 500edd09 authored by Gao Xiang's avatar Gao Xiang
Browse files

erofs: use meta buffers for inode lookup 

This converts the remaining inode lookup part by using metabuf in a
straight-forward way. Except that it doesn't use kmap_atomic()
anymore since we now have to maintain two metabufs together.

After this patch, all uncompressed paths are handled with metabuf
instead of page structure.

Link: https://lore.kernel.org/r/20220316012246.95131-2-hsiangkao@linux.alibaba.com


Reviewed-by: default avatarChao Yu <chao@kernel.org>
Signed-off-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
parent fe5de585

fs/erofs/namei.c

+24 −30
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 "xattr.h"
@@ -86,14 +87,14 @@ static struct erofs_dirent *find_target_dirent(struct erofs_qstr *name, 
	return ERR_PTR(-ENOENT);

}



static struct page *find_target_block_classic(struct inode *dir,

static void *find_target_block_classic(struct erofs_buf *target,

				       struct inode *dir,

				       struct erofs_qstr *name,

				       int *_ndirents)

{

	unsigned int startprfx, endprfx;

	int head, back;

	struct address_space *const mapping = dir->i_mapping;

	struct page *candidate = ERR_PTR(-ENOENT);

	void *candidate = ERR_PTR(-ENOENT);



	startprfx = endprfx = 0;

	head = 0;
@@ -101,10 +102,11 @@ static struct page *find_target_block_classic(struct inode *dir, 


	while (head <= back) {

		const int mid = head + (back - head) / 2;

		struct page *page = read_mapping_page(mapping, mid, NULL);

		struct erofs_buf buf = __EROFS_BUF_INITIALIZER;

		struct erofs_dirent *de;



		if (!IS_ERR(page)) {

			struct erofs_dirent *de = kmap_atomic(page);

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

		if (!IS_ERR(de)) {

			const int nameoff = nameoff_from_disk(de->nameoff,

							      EROFS_BLKSIZ);

			const int ndirents = nameoff / sizeof(*de);
@@ -113,13 +115,12 @@ static struct page *find_target_block_classic(struct inode *dir, 
			struct erofs_qstr dname;



			if (!ndirents) {

				kunmap_atomic(de);

				put_page(page);

				erofs_put_metabuf(&buf);

				erofs_err(dir->i_sb,

					  "corrupted dir block %d @ nid %llu",

					  mid, EROFS_I(dir)->nid);

				DBG_BUGON(1);

				page = ERR_PTR(-EFSCORRUPTED);

				de = ERR_PTR(-EFSCORRUPTED);

				goto out;

			}
@@ -135,7 +136,6 @@ static struct page *find_target_block_classic(struct inode *dir, 


			/* string comparison without already matched prefix */

			diff = erofs_dirnamecmp(name, &dname, &matched);

			kunmap_atomic(de);



			if (!diff) {

				*_ndirents = 0;
@@ -145,11 +145,12 @@ static struct page *find_target_block_classic(struct inode *dir, 
				startprfx = matched;



				if (!IS_ERR(candidate))

					put_page(candidate);

				candidate = page;

					erofs_put_metabuf(target);

				*target = buf;

				candidate = de;

				*_ndirents = ndirents;

			} else {

				put_page(page);

				erofs_put_metabuf(&buf);



				back = mid - 1;

				endprfx = matched;
@@ -158,8 +159,8 @@ static struct page *find_target_block_classic(struct inode *dir, 
		}

out:		/* free if the candidate is valid */

		if (!IS_ERR(candidate))

			put_page(candidate);

		return page;

			erofs_put_metabuf(target);

		return de;

	}

	return candidate;

}
@@ -169,8 +170,7 @@ int erofs_namei(struct inode *dir, 
		erofs_nid_t *nid, unsigned int *d_type)

{

	int ndirents;

	struct page *page;

	void *data;

	struct erofs_buf buf = __EROFS_BUF_INITIALIZER;

	struct erofs_dirent *de;

	struct erofs_qstr qn;
@@ -181,26 +181,20 @@ int erofs_namei(struct inode *dir, 
	qn.end = name->name + name->len;



	ndirents = 0;

	page = find_target_block_classic(dir, &qn, &ndirents);



	if (IS_ERR(page))

		return PTR_ERR(page);

	de = find_target_block_classic(&buf, dir, &qn, &ndirents);

	if (IS_ERR(de))

		return PTR_ERR(de);



	data = kmap_atomic(page);

	/* the target page has been mapped */

	if (ndirents)

		de = find_target_dirent(&qn, data, EROFS_BLKSIZ, ndirents);

	else

		de = (struct erofs_dirent *)data;

		de = find_target_dirent(&qn, (u8 *)de, EROFS_BLKSIZ, ndirents);



	if (!IS_ERR(de)) {

		*nid = le64_to_cpu(de->nid);

		*d_type = de->file_type;

	}



	kunmap_atomic(data);

	put_page(page);



	erofs_put_metabuf(&buf);

	return PTR_ERR_OR_ZERO(de);

}