Date: Wed, 20 Aug 2014 13:46:51 +0000 (UTC) From: Edward Tomasz Napierala <trasz@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r270207 - head/sys/fs/autofs Message-ID: <201408201346.s7KDkpXu014311@svn.freebsd.org>
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Author: trasz Date: Wed Aug 20 13:46:51 2014 New Revision: 270207 URL: http://svnweb.freebsd.org/changeset/base/270207 Log: Rework ".." lookup; previous one failed to properly busy the mountpoint. Reviewed by: kib@ MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Modified: head/sys/fs/autofs/autofs_vnops.c Modified: head/sys/fs/autofs/autofs_vnops.c ============================================================================== --- head/sys/fs/autofs/autofs_vnops.c Wed Aug 20 09:10:03 2014 (r270206) +++ head/sys/fs/autofs/autofs_vnops.c Wed Aug 20 13:46:51 2014 (r270207) @@ -198,6 +198,15 @@ mounted: } static int +autofs_vget_callback(struct mount *mp, void *arg, int lkflags __unused, + struct vnode **vpp) +{ + + + return (autofs_node_vn(arg, mp, vpp)); +} + +static int autofs_lookup(struct vop_lookup_args *ap) { struct vnode *dvp, *newvp, **vpp; @@ -217,24 +226,19 @@ autofs_lookup(struct vop_lookup_args *ap if (cnp->cn_flags & ISDOTDOT) { KASSERT(anp->an_parent != NULL, ("NULL parent")); /* - * Note that in this case, dvp is the child vnode, and we are - * looking up the parent vnode - exactly reverse from normal - * operation. To preserve lock order, we unlock the child - * (dvp), obtain the lock on parent (*vpp) in autofs_node_vn(), - * then relock the child. We use vhold()/vdrop() to prevent - * dvp from being freed in the meantime. + * Note that in this case, dvp is the child vnode, and we + * are looking up the parent vnode - exactly reverse from + * normal operation. Unlocking dvp requires some rather + * tricky unlock/relock dance to prevent mp from being freed; + * use vn_vget_ino_gen() which takes care of all that. */ - lock_flags = VOP_ISLOCKED(dvp); - vhold(dvp); - VOP_UNLOCK(dvp, 0); - error = autofs_node_vn(anp->an_parent, mp, vpp); + error = vn_vget_ino_gen(dvp, autofs_vget_callback, + anp->an_parent, 0, vpp); if (error != 0) { - AUTOFS_WARN("autofs_node_vn() failed with error %d", + AUTOFS_WARN("vn_vget_ino_gen() failed with error %d", error); + return (error); } - vn_lock(dvp, lock_flags | LK_RETRY); - vdrop(dvp); - return (error); }
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