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Commit ba7a4c1a authored by Al Viro's avatar Al Viro Committed by Linus Torvalds
Browse files

[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: default avatarAl Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus 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;