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Commit 2d864651 authored by Al Viro's avatar Al Viro
Browse files

introduce kern_path_mountpoint() 



Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 197df04c

fs/namei.c

+24 −11
Original line number Diff line number Diff line
@@ -2360,6 +2360,20 @@ path_mountpoint(int dfd, const char *name, struct path *path, unsigned int flags 
	return err;

}



static int

filename_mountpoint(int dfd, struct filename *s, struct path *path,

			unsigned int flags)

{

	int error = path_mountpoint(dfd, s->name, path, flags | LOOKUP_RCU);

	if (unlikely(error == -ECHILD))

		error = path_mountpoint(dfd, s->name, path, flags);

	if (unlikely(error == -ESTALE))

		error = path_mountpoint(dfd, s->name, path, flags | LOOKUP_REVAL);

	if (likely(!error))

		audit_inode(s, path->dentry, 0);

	return error;

}



/**

 * user_path_mountpoint_at - lookup a path from userland in order to umount it

 * @dfd:	directory file descriptor
@@ -2380,23 +2394,22 @@ user_path_mountpoint_at(int dfd, const char __user *name, unsigned int flags, 
{

	struct filename *s = getname(name);

	int error;



	if (IS_ERR(s))

		return PTR_ERR(s);



	error = path_mountpoint(dfd, s->name, path, flags | LOOKUP_RCU);

	if (unlikely(error == -ECHILD))

		error = path_mountpoint(dfd, s->name, path, flags);

	if (unlikely(error == -ESTALE))

		error = path_mountpoint(dfd, s->name, path, flags | LOOKUP_REVAL);



	if (likely(!error))

		audit_inode(s, path->dentry, 0);



	error = filename_mountpoint(dfd, s, path, flags);

	putname(s);

	return error;

}



int

kern_path_mountpoint(int dfd, const char *name, struct path *path,

			unsigned int flags)

{

	struct filename s = {.name = name};

	return filename_mountpoint(dfd, &s, path, flags);

}

EXPORT_SYMBOL(kern_path_mountpoint);



/*

 * It's inline, so penalty for filesystems that don't use sticky bit is

 * minimal.

include/linux/namei.h

+1 −0
Original line number Diff line number Diff line
@@ -70,6 +70,7 @@ extern struct dentry *kern_path_create(int, const char *, struct path *, unsigne 
extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);

extern void done_path_create(struct path *, struct dentry *);

extern struct dentry *kern_path_locked(const char *, struct path *);

extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int);



extern struct dentry *lookup_one_len(const char *, struct dentry *, int);