Date: Thu, 18 Apr 2013 23:20:16 +0000 (UTC) From: Rick Macklem <rmacklem@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r249630 - in head/sys: fs/nfsclient nfsclient Message-ID: <201304182320.r3INKGG6049041@svn.freebsd.org>
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Author: rmacklem Date: Thu Apr 18 23:20:16 2013 New Revision: 249630 URL: http://svnweb.freebsd.org/changeset/base/249630 Log: When an NFS unmount occurs, once vflush() writes the last dirty buffer for the last vnode on the mount back to the server, it returns. At that point, the code continues with the unmount, including freeing up the nfs specific part of the mount structure. It is possible that an nfsiod thread will try to check for an empty I/O queue in the nfs specific part of the mount structure after it has been free'd by the unmount. This patch avoids this problem by setting the iodmount entries for the mount back to NULL while holding the mutex in the unmount and checking the appropriate entry is non-NULL after acquiring the mutex in the nfsiod thread. Reported and tested by: pho Reviewed by: kib MFC after: 2 weeks Modified: head/sys/fs/nfsclient/nfs_clnfsiod.c head/sys/fs/nfsclient/nfs_clvfsops.c head/sys/nfsclient/nfs_nfsiod.c head/sys/nfsclient/nfs_vfsops.c Modified: head/sys/fs/nfsclient/nfs_clnfsiod.c ============================================================================== --- head/sys/fs/nfsclient/nfs_clnfsiod.c Thu Apr 18 22:54:41 2013 (r249629) +++ head/sys/fs/nfsclient/nfs_clnfsiod.c Thu Apr 18 23:20:16 2013 (r249630) @@ -304,6 +304,14 @@ nfssvc_iod(void *instance) } mtx_lock(&ncl_iod_mutex); /* + * Make sure the nmp hasn't been dismounted as soon as + * ncl_doio() completes for the last buffer. + */ + nmp = ncl_iodmount[myiod]; + if (nmp == NULL) + break; + + /* * If there are more than one iod on this mount, then defect * so that the iods can be shared out fairly between the mounts */ Modified: head/sys/fs/nfsclient/nfs_clvfsops.c ============================================================================== --- head/sys/fs/nfsclient/nfs_clvfsops.c Thu Apr 18 22:54:41 2013 (r249629) +++ head/sys/fs/nfsclient/nfs_clvfsops.c Thu Apr 18 23:20:16 2013 (r249630) @@ -81,6 +81,9 @@ extern struct timeval nfsboottime; extern struct nfsstats newnfsstats; extern int nfsrv_useacl; extern int nfscl_debuglevel; +extern enum nfsiod_state ncl_iodwant[NFS_MAXASYNCDAEMON]; +extern struct nfsmount *ncl_iodmount[NFS_MAXASYNCDAEMON]; +extern struct mtx ncl_iod_mutex; NFSCLSTATEMUTEX; MALLOC_DEFINE(M_NEWNFSREQ, "newnfsclient_req", "New NFS request header"); @@ -1472,7 +1475,7 @@ nfs_unmount(struct mount *mp, int mntfla { struct thread *td; struct nfsmount *nmp; - int error, flags = 0, trycnt = 0; + int error, flags = 0, i, trycnt = 0; struct nfsclds *dsp, *tdsp; td = curthread; @@ -1508,6 +1511,14 @@ nfs_unmount(struct mount *mp, int mntfla */ if ((mntflags & MNT_FORCE) == 0) nfscl_umount(nmp, td); + /* Make sure no nfsiods are assigned to this mount. */ + mtx_lock(&ncl_iod_mutex); + for (i = 0; i < NFS_MAXASYNCDAEMON; i++) + if (ncl_iodmount[i] == nmp) { + ncl_iodwant[i] = NFSIOD_AVAILABLE; + ncl_iodmount[i] = NULL; + } + mtx_unlock(&ncl_iod_mutex); newnfs_disconnect(&nmp->nm_sockreq); crfree(nmp->nm_sockreq.nr_cred); FREE(nmp->nm_nam, M_SONAME); Modified: head/sys/nfsclient/nfs_nfsiod.c ============================================================================== --- head/sys/nfsclient/nfs_nfsiod.c Thu Apr 18 22:54:41 2013 (r249629) +++ head/sys/nfsclient/nfs_nfsiod.c Thu Apr 18 23:20:16 2013 (r249630) @@ -308,6 +308,14 @@ nfssvc_iod(void *instance) mtx_unlock(&Giant); mtx_lock(&nfs_iod_mtx); /* + * Make sure the nmp hasn't been dismounted as soon as + * nfs_doio() completes for the last buffer. + */ + nmp = nfs_iodmount[myiod]; + if (nmp == NULL) + break; + + /* * If there are more than one iod on this mount, then defect * so that the iods can be shared out fairly between the mounts */ Modified: head/sys/nfsclient/nfs_vfsops.c ============================================================================== --- head/sys/nfsclient/nfs_vfsops.c Thu Apr 18 22:54:41 2013 (r249629) +++ head/sys/nfsclient/nfs_vfsops.c Thu Apr 18 23:20:16 2013 (r249630) @@ -1362,7 +1362,7 @@ static int nfs_unmount(struct mount *mp, int mntflags) { struct nfsmount *nmp; - int error, flags = 0; + int error, flags = 0, i; if (mntflags & MNT_FORCE) flags |= FORCECLOSE; @@ -1387,6 +1387,14 @@ nfs_unmount(struct mount *mp, int mntfla /* * We are now committed to the unmount. */ + /* Make sure no nfsiods are assigned to this mount. */ + mtx_lock(&nfs_iod_mtx); + for (i = 0; i < NFS_MAXASYNCDAEMON; i++) + if (nfs_iodmount[i] == nmp) { + nfs_iodwant[i] = NFSIOD_AVAILABLE; + nfs_iodmount[i] = NULL; + } + mtx_unlock(&nfs_iod_mtx); nfs_disconnect(nmp); free(nmp->nm_nam, M_SONAME);
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