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Commit 16f60ec3 authored by Al Viro's avatar Al Viro Committed by Amit Pundir
Browse files

UPSTREAM: new primitive: debugfs_create_automount() 



Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>

Bug: 31856701
Change-Id: If112981485e85f6554f64f97fe5ea396e9460330
(cherry picked from commit 77b3da6e3232d3b4d4b8addb4b05799fe98f3bf8)
Signed-off-by: default avatarPaul Lawrence <paullawrence@google.com>
parent 46e3a232

fs/debugfs/inode.c

+48 −0
Original line number Diff line number Diff line
@@ -184,6 +184,18 @@ static const struct super_operations debugfs_super_operations = { 
	.evict_inode	= debugfs_evict_inode,

};



static struct vfsmount *debugfs_automount(struct path *path)

{

	struct vfsmount *(*f)(void *);

	f = (struct vfsmount *(*)(void *))path->dentry->d_fsdata;

	return f(path->dentry->d_inode->i_private);

}



static const struct dentry_operations debugfs_dops = {

	.d_delete = always_delete_dentry,

	.d_automount = debugfs_automount,

};



static int debug_fill_super(struct super_block *sb, void *data, int silent)

{

	static struct tree_descr debug_files[] = {{""}};
@@ -208,6 +220,7 @@ static int debug_fill_super(struct super_block *sb, void *data, int silent) 
		goto fail;



	sb->s_op = &debugfs_super_operations;

	sb->s_d_op = &debugfs_dops;



	debugfs_apply_options(sb);
@@ -376,6 +389,41 @@ struct dentry *debugfs_create_dir(const char *name, struct dentry *parent) 
}

EXPORT_SYMBOL_GPL(debugfs_create_dir);



/**

 * debugfs_create_automount - create automount point in the debugfs filesystem

 * @name: a pointer to a string containing the name of the file to create.

 * @parent: a pointer to the parent dentry for this file.  This should be a

 *          directory dentry if set.  If this parameter is NULL, then the

 *          file will be created in the root of the debugfs filesystem.

 * @f: function to be called when pathname resolution steps on that one.

 * @data: opaque argument to pass to f().

 *

 * @f should return what ->d_automount() would.

 */

struct dentry *debugfs_create_automount(const char *name,

					struct dentry *parent,

					struct vfsmount *(*f)(void *),

					void *data)

{

	struct dentry *dentry = start_creating(name, parent);

	struct inode *inode;



	if (IS_ERR(dentry))

		return NULL;



	inode = debugfs_get_inode(dentry->d_sb);

	if (unlikely(!inode))

		return failed_creating(dentry);



	inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;

	inode->i_flags |= S_AUTOMOUNT;

	inode->i_private = data;

	dentry->d_fsdata = (void *)f;

	d_instantiate(dentry, inode);

	return end_creating(dentry);

}

EXPORT_SYMBOL(debugfs_create_automount);



/**

 * debugfs_create_symlink- create a symbolic link in the debugfs filesystem

 * @name: a pointer to a string containing the name of the symbolic link to

include/linux/debugfs.h

+5 −0
Original line number Diff line number Diff line
@@ -55,6 +55,11 @@ struct dentry *debugfs_create_dir(const char *name, struct dentry *parent); 
struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,

				      const char *dest);



struct dentry *debugfs_create_automount(const char *name,

					struct dentry *parent,

					struct vfsmount *(*f)(void *),

					void *data);



void debugfs_remove(struct dentry *dentry);

void debugfs_remove_recursive(struct dentry *dentry);