[WIP] [PATCH v3 12/12] erofs-utils: fuse: kill incomplate dcache - Gao Xiang via Linux-erofs

From: Gao Xiang via Linux-erofs <linux-erofs@lists.ozlabs.org>
To: linux-erofs@lists.ozlabs.org
Subject: [WIP] [PATCH v3 12/12] erofs-utils: fuse: kill incomplate dcache
Date: Mon,  2 Nov 2020 23:59:38 +0800	[thread overview]
Message-ID: <20201102155938.2679-3-hsiangkao@aol.com> (raw)
In-Reply-To: <20201102155938.2679-1-hsiangkao@aol.com>

useless at all, use simplist bare disk lookup way for now
(also libfuse has an internal dcache, we can use it as well.
 plus no need to introduce dcache for unpack tool.)

(will fold into the original patch.)

Signed-off-by: Gao Xiang <hsiangkao@aol.com>
---
 fuse/Makefile.am |   2 +-
 fuse/dentry.c    | 130 ----------------------------------
 fuse/dentry.h    |  43 ------------
 fuse/main.c      |   5 --
 fuse/namei.c     | 179 +++++++++++++++++++++++------------------------
 fuse/namei.h     |   5 --
 6 files changed, 88 insertions(+), 276 deletions(-)
 delete mode 100644 fuse/dentry.c
 delete mode 100644 fuse/dentry.h

diff --git a/fuse/Makefile.am b/fuse/Makefile.am
index 5ff0b4d0e6ab..84e5f834d6a4 100644
--- a/fuse/Makefile.am
+++ b/fuse/Makefile.am
@@ -3,7 +3,7 @@
 
 AUTOMAKE_OPTIONS = foreign
 bin_PROGRAMS     = erofsfuse
-erofsfuse_SOURCES = main.c dentry.c namei.c read.c readir.c zmap.c
+erofsfuse_SOURCES = main.c namei.c read.c readir.c zmap.c
 erofsfuse_CFLAGS = -Wall -Werror \
                    -I$(top_srcdir)/include \
                    $(shell pkg-config fuse --cflags) \
diff --git a/fuse/dentry.c b/fuse/dentry.c
deleted file mode 100644
index 0f722294d530..000000000000
--- a/fuse/dentry.c
+++ /dev/null
@@ -1,130 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0+
-/*
- * erofs-utils/fuse/dentry.c
- *
- * Created by Li Guifu <blucerlee@gmail.com>
- */
-#include <stdlib.h>
-#include "dentry.h"
-#include "erofs/internal.h"
-#include "erofs/print.h"
-
-#define DCACHE_ENTRY_CALLOC()   calloc(1, sizeof(struct dcache_entry))
-#define DCACHE_ENTRY_LIFE       8
-
-struct dcache_entry root_entry;
-
-int dcache_init_root(uint32_t nid)
-{
-	if (root_entry.nid)
-		return -1;
-
-	/* Root entry doesn't need most of the fields. Namely, it only uses the
-	 * nid field and the subdirs pointer.
-	 */
-	erofs_info("Initializing root_entry dcache entry");
-	root_entry.nid = nid;
-	root_entry.subdirs = NULL;
-	root_entry.siblings = NULL;
-
-	return 0;
-}
-
-/* Inserts a node as a subdirs of a given parent. The parent is updated to
- * point the newly inserted subdirs as the first subdirs. We return the new
- * entry so that further entries can be inserted.
- *
- *      [0]                  [0]
- *       /        ==>          \
- *      /         ==>           \
- * .->[1]->[2]-.       .->[1]->[3]->[2]-.
- * `-----------麓       `----------------麓
- */
-struct dcache_entry *dcache_insert(struct dcache_entry *parent,
-				   const char *name, int namelen, uint32_t nid)
-{
-	struct dcache_entry *new_entry;
-
-	erofs_dbg("Inserting %s,%d to dcache", name, namelen);
-
-	/* TODO: Deal with names that exceed the allocated size */
-	if (namelen + 1 > DCACHE_ENTRY_NAME_LEN)
-		return NULL;
-
-	if (parent == NULL)
-		parent = &root_entry;
-
-	new_entry = DCACHE_ENTRY_CALLOC();
-	if (!new_entry)
-		return NULL;
-
-	strncpy(new_entry->name, name, namelen);
-	new_entry->name[namelen] = 0;
-	new_entry->nid = nid;
-
-	if (!parent->subdirs) {
-		new_entry->siblings = new_entry;
-		parent->subdirs = new_entry;
-	} else {
-		new_entry->siblings = parent->subdirs->siblings;
-		parent->subdirs->siblings = new_entry;
-		parent->subdirs = new_entry;
-	}
-
-	return new_entry;
-}
-
-/* Lookup a cache entry for a given file name.  Return value is a struct pointer
- * that can be used to both obtain the nid number and insert further child
- * entries.
- * TODO: Prune entries by using the LRU counter
- */
-struct dcache_entry *dcache_lookup(struct dcache_entry *parent,
-				   const char *name, int namelen)
-{
-	struct dcache_entry *iter;
-
-	if (parent == NULL)
-		parent = &root_entry;
-
-	if (!parent->subdirs)
-		return NULL;
-
-	/* Iterate the list of siblings to see if there is any match */
-	iter = parent->subdirs;
-
-	do {
-		if (strncmp(iter->name, name, namelen) == 0 &&
-		    iter->name[namelen] == 0) {
-			parent->subdirs = iter;
-
-			return iter;
-		}
-
-		iter = iter->siblings;
-	} while (iter != parent->subdirs);
-
-	return NULL;
-}
-
-struct dcache_entry *dcache_try_insert(struct dcache_entry *parent,
-				   const char *name, int namelen, uint32_t nid)
-{
-	struct dcache_entry *d = dcache_lookup(parent, name, namelen);
-
-	if (d)
-		return d;
-
-	return dcache_insert(parent, name, namelen, nid);
-
-}
-erofs_nid_t dcache_get_nid(struct dcache_entry *entry)
-{
-	return entry ? entry->nid : root_entry.nid;
-}
-
-struct dcache_entry *dcache_root(void)
-{
-	return &root_entry;
-}
-
diff --git a/fuse/dentry.h b/fuse/dentry.h
deleted file mode 100644
index 12f4cf6bafd9..000000000000
--- a/fuse/dentry.h
+++ /dev/null
@@ -1,43 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0+ */
-/*
- * erofs-utils/fuse/dentry.h
- *
- * Created by Li Guifu <blucerlee@gmail.com>
- */
-#ifndef _EROFS_DENTRY_H
-#define _EROFS_DENTRY_H
-
-#include <stdint.h>
-#include "erofs/internal.h"
-
-/* fixme: Deal with names that exceed the allocated size */
-#ifdef __64BITS
-#define DCACHE_ENTRY_NAME_LEN       EROFS_NAME_LEN
-#else
-#define DCACHE_ENTRY_NAME_LEN       EROFS_NAME_LEN
-#endif
-
-/* This struct declares a node of a k-tree.  Every node has a pointer to one of
- * the subdirs and a pointer (in a circular list fashion) to its siblings.
- */
-
-struct dcache_entry {
-	struct dcache_entry *subdirs;
-	struct dcache_entry *siblings;
-	uint32_t nid;
-	uint16_t lru_count;
-	uint8_t user_count;
-	char name[DCACHE_ENTRY_NAME_LEN];
-};
-
-struct dcache_entry *dcache_insert(struct dcache_entry *parent,
-				   const char *name, int namelen, uint32_t n);
-struct dcache_entry *dcache_lookup(struct dcache_entry *parent,
-				   const char *name, int namelen);
-struct dcache_entry *dcache_try_insert(struct dcache_entry *parent,
-				       const char *name, int namelen,
-				       uint32_t nid);
-
-erofs_nid_t dcache_get_nid(struct dcache_entry *entry);
-int dcache_init_root(uint32_t n);
-#endif
diff --git a/fuse/main.c b/fuse/main.c
index e423312d9e1a..563b2c378952 100644
--- a/fuse/main.c
+++ b/fuse/main.c
@@ -116,11 +116,6 @@ static void signal_handle_sigsegv(int signal)
 void *erofs_init(struct fuse_conn_info *info)
 {
 	erofs_info("Using FUSE protocol %d.%d", info->proto_major, info->proto_minor);
-
-	if (inode_init(sbi.root_nid) != 0) {
-		erofs_err("inode initialization failed");
-		abort();
-	}
 	return NULL;
 }
 
diff --git a/fuse/namei.c b/fuse/namei.c
index 4c428dbc59f6..5ee3f8d2a4b6 100644
--- a/fuse/namei.c
+++ b/fuse/namei.c
@@ -16,7 +16,6 @@
 #include "erofs/defs.h"
 #include "erofs/print.h"
 #include "erofs/io.h"
-#include "dentry.h"
 
 #define IS_PATH_SEPARATOR(__c)      ((__c) == '/')
 #define MINORBITS	20
@@ -99,124 +98,127 @@ int erofs_iget_by_nid(erofs_nid_t nid, struct erofs_vnode *vi)
 	return 0;
 }
 
-/* dirent + name string */
-struct dcache_entry *list_name(const char *buf, struct dcache_entry *parent,
-				const char *name, unsigned int len,
-				uint32_t dirend)
+
+struct erofs_dirent *find_target_dirent(erofs_nid_t pnid,
+					void *dentry_blk,
+					const char *name, unsigned int len,
+					unsigned int nameoff,
+					unsigned int maxsize)
 {
-	struct dcache_entry *entry = NULL;
-	struct erofs_dirent *ds, *de;
-
-	ds = (struct erofs_dirent *)buf;
-	de = (struct erofs_dirent *)(buf + le16_to_cpu(ds->nameoff));
-
-	while (ds < de) {
-		erofs_nid_t nid = le64_to_cpu(ds->nid);
-		uint16_t nameoff = le16_to_cpu(ds->nameoff);
-		char *d_name = (char *)(buf + nameoff);
-		uint16_t name_len = (ds + 1 >= de) ?
-			(uint16_t)strnlen(d_name, dirend - nameoff) :
-			le16_to_cpu(ds[1].nameoff) - nameoff;
-
-		#if defined(EROFS_DEBUG_ENTRY)
-		{
-			char debug[EROFS_BLKSIZ];
-
-			memcpy(debug, d_name, name_len);
-			debug[name_len] = '\0';
-			erofs_info("list entry: %s nid=%u", debug, nid);
+	struct erofs_dirent *de = dentry_blk;
+	const struct erofs_dirent *end = dentry_blk + nameoff;
+
+	while (de < end) {
+		const char *de_name;
+		unsigned int de_namelen;
+
+		nameoff = le16_to_cpu(de->nameoff);
+		de_name = (char *)dentry_blk + nameoff;
+
+		/* the last dirent in the block? */
+		if (de + 1 >= end)
+			de_namelen = strnlen(de_name, maxsize - nameoff);
+		else
+			de_namelen = le16_to_cpu(de[1].nameoff) - nameoff;
+
+		/* a corrupted entry is found */
+		if (nameoff + de_namelen > maxsize ||
+		    de_namelen > EROFS_NAME_LEN) {
+			erofs_err("bogus dirent @ nid %llu", pnid | 0ULL);
+			DBG_BUGON(1);
+			return ERR_PTR(-EFSCORRUPTED);
 		}
-		#endif
-
-		entry = dcache_try_insert(parent, d_name, name_len, nid);
-		if (len == name_len && !memcmp(name, d_name, name_len))
-			return entry;
 
-		entry = NULL;
-		++ds;
+		if (len == de_namelen && !memcmp(de_name, name, de_namelen))
+			return de;
+		++de;
 	}
-
-	return entry;
+	return NULL;
 }
 
-struct dcache_entry *disk_lookup(struct dcache_entry *parent, const char *name,
-		unsigned int name_len)
+int erofs_namei(erofs_nid_t *nid,
+		const char *name, unsigned int len)
 {
 	int ret;
 	char buf[EROFS_BLKSIZ];
-	struct dcache_entry *entry = NULL;
 	struct erofs_vnode v;
-	uint32_t nr_cnt, dir_nr, dirsize, blkno;
 
-	ret = erofs_iget_by_nid(parent->nid, &v);
+	ret = erofs_iget_by_nid(*nid, &v);
 	if (ret)
-		return NULL;
-
-	/* to check whether dirent is in the inline dirs */
-	blkno = v.raw_blkaddr;
-	dirsize = v.i_size;
-	dir_nr = erofs_blknr(dirsize);
-
-	nr_cnt = 0;
-	while (nr_cnt < dir_nr) {
-		ret = blk_read(buf, blkno + nr_cnt, 1);
-		if (ret < 0)
-			return NULL;
-
-		entry = list_name(buf, parent, name, name_len, EROFS_BLKSIZ);
-		if (entry)
-			goto next;
-
-		++nr_cnt;
-	}
-
-	if (v.datalayout == EROFS_INODE_FLAT_INLINE) {
-		uint32_t dir_off = erofs_blkoff(dirsize);
-		off_t dir_addr = iloc(dcache_get_nid(parent)) +
-			v.inode_isize + v.xattr_isize;
-
-		memset(buf, 0, sizeof(buf));
-		ret = dev_read(buf, dir_addr, dir_off);
-		if (ret < 0)
-			return NULL;
+		return ret;
 
-		entry = list_name(buf, parent, name, name_len, dir_off);
+	{
+		unsigned int offset = 0;
+
+		struct erofs_inode tmp = {
+			.u = {
+				.i_blkaddr = v.raw_blkaddr,
+			},
+			.nid = v.nid,
+			.i_size = v.i_size,
+			.datalayout = v.datalayout,
+			.inode_isize = v.inode_isize,
+			.xattr_isize = v.xattr_isize,
+		};
+
+		while (offset < v.i_size) {
+			int maxsize = min(v.i_size - offset, EROFS_BLKSIZ);
+			struct erofs_dirent *de = (void *)buf;
+			unsigned int nameoff;
+
+			ret = erofs_read_raw_data(&tmp, buf, offset, maxsize);
+			if (ret)
+				return ret;
+
+			nameoff = le16_to_cpu(de->nameoff);
+
+			if (nameoff < sizeof(struct erofs_dirent) ||
+			    nameoff >= PAGE_SIZE) {
+				erofs_err("invalid de[0].nameoff %u @ nid %llu",
+					  nameoff, *nid | 0ULL);
+				return -EFSCORRUPTED;
+			}
+
+			de = find_target_dirent(*nid, buf, name, len,
+						nameoff, maxsize);
+			if (IS_ERR(de))
+				return PTR_ERR(de);
+
+			if (de) {
+				*nid = le64_to_cpu(de->nid);
+				return 0;
+			}
+			offset += maxsize;
+		}
 	}
-next:
-	return entry;
+	return -ENOENT;
 }
 
 extern struct dcache_entry root_entry;
 int walk_path(const char *_path, erofs_nid_t *out_nid)
 {
-	struct dcache_entry *next, *ret;
+	int ret;
+	erofs_nid_t nid = sbi.root_nid;
 	const char *path = _path;
 
-	ret = next = &root_entry;
 	for (;;) {
 		uint8_t path_len;
 
 		path = skip_trailing_backslash(path);
 		path_len = get_path_token_len(path);
-		ret = next;
 		if (path_len == 0)
 			break;
 
-		next = dcache_lookup(ret, path, path_len);
-		if (!next) {
-			next = disk_lookup(ret, path, path_len);
-			if (!next)
-				return -ENOENT;
-		}
+		ret = erofs_namei(&nid, path, path_len);
+		if (ret)
+			return ret;
 
 		path += path_len;
 	}
 
-	if (!ret)
-		return -ENOENT;
-	erofs_dbg("find path = %s nid=%u", _path, ret->nid);
+	erofs_dbg("find path = %s nid=%llu", _path, nid | 0ULL);
 
-	*out_nid = ret->nid;
+	*out_nid = nid;
 	return 0;
 
 }
@@ -233,10 +235,3 @@ int erofs_iget_by_path(const char *path, struct erofs_vnode *v)
 	return erofs_iget_by_nid(nid, v);
 }
 
-int inode_init(erofs_nid_t root)
-{
-	dcache_init_root(root);
-
-	return 0;
-}
-
diff --git a/fuse/namei.h b/fuse/namei.h
index 1803a673daaf..2625ec58d434 100644
--- a/fuse/namei.h
+++ b/fuse/namei.h
@@ -10,13 +10,8 @@
 #include "erofs/internal.h"
 #include "erofs_fs.h"
 
-int inode_init(erofs_nid_t root);
-struct dcache_entry *get_cached_dentry(struct dcache_entry **parent,
-				       const char **path);
 int erofs_iget_by_path(const char *path, struct erofs_vnode *v);
 int erofs_iget_by_nid(erofs_nid_t nid, struct erofs_vnode *v);
-struct dcache_entry *disk_lookup(struct dcache_entry *parent, const char *name,
-		unsigned int name_len);
 int walk_path(const char *path, erofs_nid_t *out_nid);
 
 #endif
-- 
2.24.0

