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	 407c6726ca
			
		
	
	
		407c6726ca
		
	
	
	
	
		
			
			Looking at how dentry is removed via the tracefs system, I found that
eventfs does not do everything that it did under tracefs. The tracefs
removal of a dentry calls simple_recursive_removal() that does a lot more
than a simple d_invalidate().
As it should be a requirement that any eventfs_inode that has a dentry, so
does its parent. When removing a eventfs_inode, if it has a dentry, a call
to simple_recursive_removal() on that dentry should clean up all the
dentries underneath it.
Add WARN_ON_ONCE() to check for the parent having a dentry if any children
do.
Link: https://lore.kernel.org/all/20231101022553.GE1957730@ZenIV/
Link: https://lkml.kernel.org/r/20231101172650.552471568@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Fixes: 5bdcd5f533 ("eventfs: Implement removal of meta data from eventfs")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
		
	
			
		
			
				
	
	
		
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			82 lines
		
	
	
	
		
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| /* SPDX-License-Identifier: GPL-2.0 */
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| #ifndef _TRACEFS_INTERNAL_H
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| #define _TRACEFS_INTERNAL_H
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| 
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| enum {
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| 	TRACEFS_EVENT_INODE		= BIT(1),
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| 	TRACEFS_EVENT_TOP_INODE		= BIT(2),
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| };
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| 
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| struct tracefs_inode {
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| 	unsigned long           flags;
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| 	void                    *private;
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| 	struct inode            vfs_inode;
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| };
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| 
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| /*
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|  * struct eventfs_attr - cache the mode and ownership of a eventfs entry
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|  * @mode:	saved mode plus flags of what is saved
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|  * @uid:	saved uid if changed
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|  * @gid:	saved gid if changed
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|  */
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| struct eventfs_attr {
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| 	int				mode;
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| 	kuid_t				uid;
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| 	kgid_t				gid;
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| };
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| 
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| /*
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|  * struct eventfs_inode - hold the properties of the eventfs directories.
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|  * @list:	link list into the parent directory
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|  * @entries:	the array of entries representing the files in the directory
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|  * @name:	the name of the directory to create
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|  * @children:	link list into the child eventfs_inode
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|  * @dentry:     the dentry of the directory
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|  * @d_parent:   pointer to the parent's dentry
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|  * @d_children: The array of dentries to represent the files when created
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|  * @entry_attrs: Saved mode and ownership of the @d_children
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|  * @attr:	Saved mode and ownership of eventfs_inode itself
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|  * @data:	The private data to pass to the callbacks
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|  * @is_freed:	Flag set if the eventfs is on its way to be freed
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|  *                Note if is_freed is set, then dentry is corrupted.
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|  * @nr_entries: The number of items in @entries
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|  */
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| struct eventfs_inode {
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| 	struct list_head		list;
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| 	const struct eventfs_entry	*entries;
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| 	const char			*name;
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| 	struct list_head		children;
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| 	struct dentry			*dentry; /* Check is_freed to access */
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| 	struct dentry			*d_parent;
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| 	struct dentry			**d_children;
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| 	struct eventfs_attr		*entry_attrs;
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| 	struct eventfs_attr		attr;
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| 	void				*data;
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| 	/*
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| 	 * Union - used for deletion
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| 	 * @llist:	for calling dput() if needed after RCU
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| 	 * @rcu:	eventfs_inode to delete in RCU
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| 	 */
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| 	union {
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| 		struct llist_node	llist;
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| 		struct rcu_head		rcu;
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| 	};
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| 	unsigned int			is_freed:1;
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| 	unsigned int			nr_entries:31;
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| };
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| 
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| static inline struct tracefs_inode *get_tracefs(const struct inode *inode)
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| {
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| 	return container_of(inode, struct tracefs_inode, vfs_inode);
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| }
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| 
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| struct dentry *tracefs_start_creating(const char *name, struct dentry *parent);
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| struct dentry *tracefs_end_creating(struct dentry *dentry);
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| struct dentry *tracefs_failed_creating(struct dentry *dentry);
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| struct inode *tracefs_get_inode(struct super_block *sb);
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| struct dentry *eventfs_start_creating(const char *name, struct dentry *parent);
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| struct dentry *eventfs_failed_creating(struct dentry *dentry);
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| struct dentry *eventfs_end_creating(struct dentry *dentry);
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| void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry);
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| 
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| #endif /* _TRACEFS_INTERNAL_H */
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