Date: Fri, 5 Sep 2014 13:25:27 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r271162 - stable/10/sys/ufs/ufs Message-ID: <201409051325.s85DPR9f012406@svn.freebsd.org>
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Author: kib Date: Fri Sep 5 13:25:27 2014 New Revision: 271162 URL: http://svnweb.freebsd.org/changeset/base/271162 Log: MFC r270797: Direct access to the quota files, in particular, lookup, causes lock conflict with the quota metadata access. Mark quota vnode lock as recursive and always exclusive to avoid the problem. Approved by: re (gjb) Modified: stable/10/sys/ufs/ufs/ufs_quota.c Directory Properties: stable/10/ (props changed) Modified: stable/10/sys/ufs/ufs/ufs_quota.c ============================================================================== --- stable/10/sys/ufs/ufs/ufs_quota.c Fri Sep 5 13:22:28 2014 (r271161) +++ stable/10/sys/ufs/ufs/ufs_quota.c Fri Sep 5 13:25:27 2014 (r271162) @@ -557,8 +557,21 @@ quotaon(struct thread *td, struct mount if (*vpp != vp) quotaoff1(td, mp, type); + /* + * When the directory vnode containing the quota file is + * inactivated, due to the shared lookup of the quota file + * vput()ing the dvp, the qsyncvp() call for the containing + * directory would try to acquire the quota lock exclusive. + * At the same time, lookup already locked the quota vnode + * shared. Mark the quota vnode lock as allowing recursion + * and automatically converting shared locks to exclusive. + * + * Also mark quota vnode as system. + */ vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); vp->v_vflag |= VV_SYSTEM; + VN_LOCK_AREC(vp); + VN_LOCK_DSHARE(vp); VOP_UNLOCK(vp, 0); *vpp = vp; /*
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