From b235a0f3410f4c1c4a15fb010bb6c6dc06120665 Mon Sep 17 00:00:00 2001
From: ChenXiaoSong <chenxiaosong@chenxiaosong.com>
Date: Thu, 16 May 2024 08:01:27 +0000
Subject: [PATCH] debug vfs

Signed-off-by: ChenXiaoSong <chenxiaosong@chenxiaosong.com>
---
 fs/ext2/dir.c      |  4 +++
 fs/ext2/file.c     |  6 ++++
 fs/namei.c         | 89 ++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/fs.h |  4 ++-
 4 files changed, 102 insertions(+), 1 deletion(-)

diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c
index b335f17f682f..c96ee8e59805 100644
--- a/fs/ext2/dir.c
+++ b/fs/ext2/dir.c
@@ -266,6 +266,10 @@ ext2_readdir(struct file *file, struct dir_context *ctx)
 	bool need_revalidate = !inode_eq_iversion(inode, file->f_version);
 	bool has_filetype;
 
+	debug_get_full_path(inode);
+	debug_inode_nlink(inode);
+	debug_sb_mounts(inode);
+
 	if (pos > inode->i_size - EXT2_DIR_REC_LEN(1))
 		return 0;
 
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index 1039e5bf90af..3b34278c81e6 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -281,6 +281,12 @@ static ssize_t ext2_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
 
 static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file_inode(file);
+	debug_get_full_path(inode);
+	debug_inode_nlink(inode);
+	debug_sb_mounts(inode);
+
 #ifdef CONFIG_FS_DAX
 	if (IS_DAX(iocb->ki_filp->f_mapping->host))
 		return ext2_dax_read_iter(iocb, to);
diff --git a/fs/namei.c b/fs/namei.c
index 94565bd7e73f..7ba2e6701091 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -5227,3 +5227,92 @@ const struct inode_operations page_symlink_inode_operations = {
 	.get_link	= page_get_link,
 };
 EXPORT_SYMBOL(page_symlink_inode_operations);
+
+void debug_inode_nlink(struct inode *inode)
+{
+	unsigned int nlink = inode->i_nlink;
+	struct dentry *tmp = NULL;
+	printk("%s:%d, inode:%px, nlink:%d\n",
+	       __func__, __LINE__, inode, nlink);
+
+	/*
+	struct hlist_head i_dentry
+	struct hlist_node d_alias
+
+	hlist_for_each_entry(pos=tmp, &i_dentry=&inode->i_dentry, member=d_u.d_alias)
+
+	for (tmp = container_of((&i_dentry)->first, struct dentry, member);\
+	     tmp;                                                       \
+	     tmp = container_of((tmp)->member.next, struct dentry, member))
+	 */
+	hlist_for_each_entry(tmp, &inode->i_dentry, d_u.d_alias) {
+		printk("%s:%d, name:%s, dentry:%px, inode:%px\n",
+		       __func__, __LINE__, tmp->d_name.name, tmp, tmp->d_inode);
+	}
+}
+EXPORT_SYMBOL(debug_inode_nlink);
+
+void debug_sb_mounts(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+	struct mount *mnt;
+	char *buffer = (char *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+	char *mpt_path;
+	printk("%s:%d, sb:%px\n", __func__, __LINE__, sb);
+	/*
+	struct list_head mnt_instance
+	struct list_head s_mounts
+	 */
+	list_for_each_entry(mnt, &sb->s_mounts, mnt_instance) {
+		mpt_path = dentry_path_raw(mnt->mnt_mountpoint, buffer,
+					    PAGE_SIZE);
+		printk("%s:%d, mountpoint path:%s, mnt_mountpoint:%px, mnt:%px, sb:%px\n", __func__, __LINE__, mpt_path, mnt->mnt_mountpoint, mnt, mnt->mnt.mnt_sb);
+	}
+	free_page((unsigned long)buffer);
+}
+EXPORT_SYMBOL(debug_sb_mounts);
+
+void debug_get_full_path(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+	char *buffer = (char *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+	char *tmp_path = (char *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+	char *full_path = (char *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+	struct mount *mnt;
+	char *file_path;
+	struct dentry *dentry = d_find_alias(inode);
+
+	file_path = dentry_path_raw(dentry, buffer, PAGE_SIZE);
+
+	while (1) {
+		printk("%s:%d, file_path:%s\n", __func__, __LINE__, file_path);
+		memcpy(tmp_path, full_path, PAGE_SIZE);
+		snprintf(full_path, PAGE_SIZE, "%s%s", file_path, tmp_path);
+		printk("%s:%d, full_path:%s\n", __func__, __LINE__, full_path);
+		/*
+		struct list_head s_mounts
+		struct list_head mnt_instance
+
+		list_for_each_entry(pos=mnt, &s_mounts=&sb->s_mounts, member=mnt_instance)
+
+		for (mnt = list_first_entry((&s_mounts)->next, struct struct mount, member);        \
+		     !list_entry_is_head(mnt, head, member);                    \
+		     pos = list_next_entry(mnt, member))
+		 */
+		list_for_each_entry(mnt, &sb->s_mounts, mnt_instance) {
+			file_path = dentry_path_raw(mnt->mnt_mountpoint, buffer,
+						    PAGE_SIZE);
+			sb = mnt->mnt_mountpoint->d_inode->i_sb;
+			break;
+		}
+		// sb is new super block
+		if (mnt->mnt.mnt_sb == sb)
+			break;
+	}
+
+	free_page((unsigned long)buffer);
+	free_page((unsigned long)tmp_path);
+	free_page((unsigned long)full_path);
+	dput(dentry); // 与d_find_alias配套
+}
+EXPORT_SYMBOL(debug_get_full_path);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 4a40823c3c67..d6d27e96ca88 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3377,5 +3377,7 @@ extern int vfs_fadvise(struct file *file, loff_t offset, loff_t len,
 		       int advice);
 extern int generic_fadvise(struct file *file, loff_t offset, loff_t len,
 			   int advice);
-
+extern void debug_inode_nlink(struct inode *inode);
+extern void debug_get_full_path(struct inode *inode);
+extern void debug_sb_mounts(struct inode *inode);
 #endif /* _LINUX_FS_H */
-- 
2.34.1