Commit ba7a4c1a authored Jun 06, 2005 by Al Viro Committed by Linus Torvalds Jun 06, 2005

[PATCH] namei fixes (13/19)



In open_namei() exit_dput: we have mntput() done in the wrong order -
if nd->mnt != path.mnt we end up doing
	mntput(nd->mnt);
	nd->mnt = path.mnt;
	dput(nd->dentry);
	mntput(nd->mnt);
which drops nd->dentry too late.  Fixed by having path.mnt go first.
That allows to switch O_NOFOLLOW under if (__follow_mount(...)) back
to exit_dput, while we are at it.

Fix for early-mntput() race + equivalent transformation.

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 a15a3f6f

fs/namei.c

+3 −7

Original line number	Diff line number	Diff line
		@@ -1501,11 +1501,8 @@ do_last:

		if (__follow_mount(&path)) {
		error = -ELOOP;
		if (flag & O_NOFOLLOW) {
		dput(path.dentry);
		mntput(path.mnt);
		goto exit;
		}
		if (flag & O_NOFOLLOW)
		goto exit_dput;
		}
		error = -ENOENT;
		if (!path.dentry->d_inode)
		@@ -1530,8 +1527,7 @@ ok:
		exit_dput:
		dput(path.dentry);
		if (nd->mnt != path.mnt)
		mntput(nd->mnt);
		nd->mnt = path.mnt;
		mntput(path.mnt);
		exit:
		path_release(nd);
		return error;

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