Commit 3a291c97 authored by Al Viro's avatar Al Viro
Browse files

d_path: saner calling conventions for __dentry_path() 



1) lift NUL-termination into the callers
2) pass pointer to the end of buffer instead of that to beginning.

(1) allows to simplify dentry_path() - we don't need to play silly
games with restoring the leading / of "//deleted" after __dentry_path()
would've overwritten it with NUL.

We also do not need to check if (either) prepend() in there fails -
if the buffer is not large enough, we'll end with negative buflen
after prepend() and __dentry_path() will return the right value
(ERR_PTR(-ENAMETOOLONG)) just fine.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent dfe50876

fs/d_path.c

+13 −20
Original line number Diff line number Diff line
@@ -326,22 +326,21 @@ char *simple_dname(struct dentry *dentry, char *buffer, int buflen) 
/*

 * Write full pathname from the root of the filesystem into the buffer.

 */

static char *__dentry_path(const struct dentry *d, char *buf, int buflen)

static char *__dentry_path(const struct dentry *d, char *p, int buflen)

{

	const struct dentry *dentry;

	char *end, *retval;

	int len, seq = 0;

	int error = 0;



	if (buflen < 2)

	if (buflen < 1)

		goto Elong;



	rcu_read_lock();

restart:

	dentry = d;

	end = buf + buflen;

	end = p;

	len = buflen;

	prepend(&end, &len, "", 1);

	/* Get '/' right */

	retval = end-1;

	*retval = '/';
@@ -373,27 +372,21 @@ static char *__dentry_path(const struct dentry *d, char *buf, int buflen) 


char *dentry_path_raw(const struct dentry *dentry, char *buf, int buflen)

{

	return __dentry_path(dentry, buf, buflen);

	char *p = buf + buflen;

	prepend(&p, &buflen, "", 1);

	return __dentry_path(dentry, p, buflen);

}

EXPORT_SYMBOL(dentry_path_raw);



char *dentry_path(const struct dentry *dentry, char *buf, int buflen)

{

	char *p = NULL;

	char *retval;

	char *p = buf + buflen;



	if (d_unlinked(dentry)) {

		p = buf + buflen;

		if (prepend(&p, &buflen, "//deleted", 10) != 0)

			goto Elong;

		buflen++;

	}

	retval = __dentry_path(dentry, buf, buflen);

	if (!IS_ERR(retval) && p)

		*p = '/';	/* restore '/' overriden with '\0' */

	return retval;

Elong:

	return ERR_PTR(-ENAMETOOLONG);

	if (unlikely(d_unlinked(dentry)))

		prepend(&p, &buflen, "//deleted", 10);

	else

		prepend(&p, &buflen, "", 1);

	return __dentry_path(dentry, p, buflen);

}



static void get_fs_root_and_pwd_rcu(struct fs_struct *fs, struct path *root,