Commit a4f5b521 authored by Al Viro's avatar Al Viro
Browse files

step_into(): lose inode argument 



make handle_mounts() always fetch it.  This is just the first step -
the callers of step_into() will stop trying to calculate the sucker,
etc.

The passed value should be equal to dentry->d_inode in all cases;
in RCU mode - fetched after we'd sampled ->d_seq.  Might as well
fetch it here.  We do need to validate ->d_seq, which duplicates
the check currently done in lookup_fast(); that duplication will
go away shortly.

After that change handle_mounts() always ignores the initial value of
*inode and always sets it on success.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 03fa86e9

fs/namei.c

+9 −6
Original line number Diff line number Diff line
@@ -1536,6 +1536,9 @@ static inline int handle_mounts(struct nameidata *nd, struct dentry *dentry, 
	path->dentry = dentry;

	if (nd->flags & LOOKUP_RCU) {

		unsigned int seq = nd->next_seq;

		*inode = dentry->d_inode;

		if (read_seqcount_retry(&dentry->d_seq, seq))

			return -ECHILD;

		if (unlikely(!*inode))

			return -ENOENT;

		if (likely(__follow_mount_rcu(nd, path, inode)))
@@ -1848,9 +1851,10 @@ static const char *pick_link(struct nameidata *nd, struct path *link, 
 * NOTE: dentry must be what nd->next_seq had been sampled from.

 */

static const char *step_into(struct nameidata *nd, int flags,

		     struct dentry *dentry, struct inode *inode)

		     struct dentry *dentry)

{

	struct path path;

	struct inode *inode;

	int err = handle_mounts(nd, dentry, &path, &inode);



	if (err < 0)
@@ -1976,7 +1980,7 @@ static const char *handle_dots(struct nameidata *nd, int type) 
			parent = follow_dotdot(nd, &inode);

		if (IS_ERR(parent))

			return ERR_CAST(parent);

		error = step_into(nd, WALK_NOFOLLOW, parent, inode);

		error = step_into(nd, WALK_NOFOLLOW, parent);

		if (unlikely(error))

			return error;
@@ -2021,7 +2025,7 @@ static const char *walk_component(struct nameidata *nd, int flags) 
	}

	if (!(flags & WALK_MORE) && nd->depth)

		put_link(nd);

	return step_into(nd, flags, dentry, inode);

	return step_into(nd, flags, dentry);

}



/*
@@ -2480,8 +2484,7 @@ static int handle_lookup_down(struct nameidata *nd) 
	if (!(nd->flags & LOOKUP_RCU))

		dget(nd->path.dentry);

	nd->next_seq = nd->seq;

	return PTR_ERR(step_into(nd, WALK_NOFOLLOW,

			nd->path.dentry, nd->inode));

	return PTR_ERR(step_into(nd, WALK_NOFOLLOW, nd->path.dentry));

}



/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
@@ -3470,7 +3473,7 @@ static const char *open_last_lookups(struct nameidata *nd, 
finish_lookup:

	if (nd->depth)

		put_link(nd);

	res = step_into(nd, WALK_TRAILING, dentry, inode);

	res = step_into(nd, WALK_TRAILING, dentry);

	if (unlikely(res))

		nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL);

	return res;