Date: Thu, 9 Aug 2012 19:26:58 +0100 From: Attilio Rao <attilio@freebsd.org> To: Harald Schmalzbauer <h.schmalzbauer@omnilan.de> Cc: stable@freebsd.org, daichi@freebsd.org, Pavel Polyakov <bsd@kobyla.org> Subject: Re: lock violation in unionfs (9.0-STABLE r230270) Message-ID: <CAJ-FndDkuXksyFD2Nd-S7Ty3N8boSk37=a2nYagMkguRYd1r%2Bg@mail.gmail.com> In-Reply-To: <5022840B.3060708@omnilan.de> References: <op.v9l1byf89gyv16@pp> <CAJ-FndAFMV2iHcMKvMruCP%2BHRzwQuY1Jcd_o6ZEnTCiPV8_8oA@mail.gmail.com> <op.waqux6rr9gyv16@cel.home> <5022840B.3060708@omnilan.de>
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[-- Attachment #1 --] On 8/8/12, Harald Schmalzbauer <h.schmalzbauer@omnilan.de> wrote: > schrieb Pavel Polyakov am 06.03.2012 11:20 (localtime): >>>> mount -t unionfs -o noatime /usr /mnt >>>> >>>> insmntque: mp-safe fs and non-locked vp: 0xfffffe01d96704f0 is not >>>> exclusive locked but should be >>>> KDB: enter: lock violation >>> >>> Pavel, >>> can you give a spin to this patch?: >>> http://www.freebsd.org/~attilio/unionfs_missing_insmntque_lock.patch >>> >>> I think that the unlocking is due at that point as the vnode lock can >>> be switch later on. >>> >>> Let me know what you think about it and what the test does. >> >> Thanks! >> This patch fixes the problem with lock violation. Sorry I've tested it so >> late. > > Hello, > > this patch still applies cleanly to RELENG_9_1. Was there another fix > for the issue or has it just not been PR-sent and thus forgotten? Can you and Pavel try the attached patch? Unfortunately I had no time to test it, I just made in 5 free mins from a non-FreeBSD workstation, then you should be able to tell me if it works or not, even compiling it on a RELENG_9_1. Please try with INVARIANTS option on. Thanks, Attilio -- Peace can only be achieved by understanding - A. Einstein [-- Attachment #2 --] Index: sys/fs/unionfs/union_subr.c =================================================================== --- sys/fs/unionfs/union_subr.c (revision 239152) +++ sys/fs/unionfs/union_subr.c (working copy) @@ -237,7 +237,8 @@ unionfs_nodeget(struct mount *mp, struct vnode *up if (vp != NULLVP) { vref(vp); *vpp = vp; - goto unionfs_nodeget_out; + lockmgr(vp->v_vnlock, LK_EXCLUSIVE, NULL); + return (0); } } @@ -255,17 +256,19 @@ unionfs_nodeget(struct mount *mp, struct vnode *up */ unp = malloc(sizeof(struct unionfs_node), M_UNIONFSNODE, M_WAITOK | M_ZERO); + if (path != NULL) { + unp->un_path = (char *) + malloc(cnp->cn_namelen +1, M_UNIONFSPATH, M_WAITOK|M_ZERO); + bcopy(cnp->cn_nameptr, unp->un_path, cnp->cn_namelen); + unp->un_path[cnp->cn_namelen] = '\0'; + } error = getnewvnode("unionfs", mp, &unionfs_vnodeops, &vp); if (error != 0) { + free(unp->un_path, M_UNIONFSNODE); free(unp, M_UNIONFSNODE); return (error); } - error = insmntque(vp, mp); /* XXX: Too early for mpsafe fs */ - if (error != 0) { - free(unp, M_UNIONFSNODE); - return (error); - } if (dvp != NULLVP) vref(dvp); if (uppervp != NULLVP) @@ -286,15 +289,22 @@ unionfs_nodeget(struct mount *mp, struct vnode *up else vp->v_vnlock = lowervp->v_vnlock; - if (path != NULL) { - unp->un_path = (char *) - malloc(cnp->cn_namelen +1, M_UNIONFSPATH, M_WAITOK|M_ZERO); - bcopy(cnp->cn_nameptr, unp->un_path, cnp->cn_namelen); - unp->un_path[cnp->cn_namelen] = '\0'; - } vp->v_type = vt; vp->v_data = unp; + lockmgr(vp->v_vnlock, LK_EXCLUSIVE, NULL); + error = insmntque(vp, mp); + if (error != 0) { + if (dvp != NULLVP) + vrele(dvp); + if (uppervp != NULLVP) + vrele(uppervp); + if (lowervp != NULLVP) + vrele(lowervp); + free(unp->un_path, M_UNIONFSNODE); + free(unp, M_UNIONFSNODE); + return (error); + } if ((uppervp != NULLVP && ump->um_uppervp == uppervp) && (lowervp != NULLVP && ump->um_lowervp == lowervp)) vp->v_vflag |= VV_ROOT; @@ -317,11 +327,6 @@ unionfs_nodeget(struct mount *mp, struct vnode *up vref(vp); } else *vpp = vp; - -unionfs_nodeget_out: - if (lkflags & LK_TYPE_MASK) - vn_lock(vp, lkflags | LK_RETRY); - return (0); }
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