Commit 839d9f93 authored Jun 06, 2005 by Al Viro Committed by Linus Torvalds Jun 06, 2005

[PATCH] namei fixes (6/19)



mntget(path->mnt) in do_follow_link() moved down to right before the
__do_follow_link() call and rigth after loop: resp.

dput()+mntput() on non-ELOOP branch moved up to right after __do_follow_link()
call.

resulting
loop:
	mntget(path->mnt);
	path_release(nd);
	dput(path->mnt);
	mntput(path->mnt);
replaced with equivalent
	dput(path->mnt);
	path_release(nd);

Equivalent transformations - the reason why we have that mntget() is that
__do_follow_link() can drop a reference to nd->mnt and that's what holds
path->mnt.  So that call can happen at any point prior to __do_follow_link()
touching nd->mnt.  The rest is obvious.

NOTE: current tree relies on symlinks *never* being mounted on anything.  It's
not hard to get rid of that assumption (actually, that will come for free
later in the series).  For now we are just not making the situation worse than
it is.

Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent 1be4a090

fs/namei.c

+4 −5

Original line number	Diff line number	Diff line
		@@ -526,7 +526,6 @@ static inline int __do_follow_link(struct dentry dentry, struct nameidata nd)
		static inline int do_follow_link(struct path path, struct nameidata nd)
		{
		int err = -ELOOP;
		mntget(path->mnt);
		if (current->link_count >= MAX_NESTED_LINKS)
		goto loop;
		if (current->total_link_count >= 40)
		@@ -539,16 +538,16 @@ static inline int do_follow_link(struct path path, struct nameidata nd)
		current->link_count++;
		current->total_link_count++;
		nd->depth++;
		mntget(path->mnt);
		err = __do_follow_link(path->dentry, nd);
		current->link_count--;
		nd->depth--;
		dput(path->dentry);
		mntput(path->mnt);
		current->link_count--;
		nd->depth--;
		return err;
		loop:
		path_release(nd);
		dput(path->dentry);
		mntput(path->mnt);
		path_release(nd);
		return err;
		}

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