> Author: asomers > Date: Thu Jun 6 15:04:50 2019 > New Revision: 348737 > URL: https://svnweb.freebsd.org/changeset/base/348737 > > Log: > Add a testing facility to manually reclaim a vnode > > Add the debug.try_reclaim_vnode sysctl. When a pathname is written to it, it > will be reclaimed, as long as it isn't already or doomed. The purpose is to > gain test coverage for vnode reclamation, which is otherwise hard to > achieve. > > Add the debug.ftry_reclaim_vnode sysctl. It does the same thing, except > that its argument is a file descriptor instead of a pathname.
Should not this all be wrapped in some #ifdef or other protection, is it really a good idea to have this on every single box running FreeBSD? > > Reviewed by: kib > MFC after: 2 weeks > Sponsored by: The FreeBSD Foundation > Differential Revision: https://reviews.freebsd.org/D20519 > > Modified: > head/sys/kern/vfs_subr.c > > Modified: head/sys/kern/vfs_subr.c > ============================================================================== > --- head/sys/kern/vfs_subr.c Thu Jun 6 12:44:43 2019 (r348736) > +++ head/sys/kern/vfs_subr.c Thu Jun 6 15:04:50 2019 (r348737) > @@ -50,6 +50,7 @@ __FBSDID("$FreeBSD$"); > #include <sys/systm.h> > #include <sys/bio.h> > #include <sys/buf.h> > +#include <sys/capsicum.h> > #include <sys/condvar.h> > #include <sys/conf.h> > #include <sys/counter.h> > @@ -338,6 +339,93 @@ SYSCTL_ULONG(_kern, OID_AUTO, minvnodes, CTLFLAG_RW, > static int vnlru_nowhere; > SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RW, > &vnlru_nowhere, 0, "Number of times the vnlru process ran without > success"); > + > +static int > +sysctl_try_reclaim_vnode(SYSCTL_HANDLER_ARGS) > +{ > + struct vnode *vp; > + struct nameidata nd; > + char *buf; > + unsigned long ndflags; > + int error; > + > + if (req->newptr == NULL) > + return (EINVAL); > + if (req->newlen > PATH_MAX) > + return (E2BIG); > + > + buf = malloc(PATH_MAX + 1, M_TEMP, M_WAITOK); > + error = SYSCTL_IN(req, buf, req->newlen); > + if (error != 0) > + goto out; > + > + buf[req->newlen] = '\0'; > + > + ndflags = LOCKLEAF | NOFOLLOW | AUDITVNODE1 | NOCACHE | SAVENAME; > + NDINIT(&nd, LOOKUP, ndflags, UIO_SYSSPACE, buf, curthread); > + if ((error = namei(&nd)) != 0) > + goto out; > + vp = nd.ni_vp; > + > + if ((vp->v_iflag & VI_DOOMED) != 0) { > + /* > + * This vnode is being recycled. Return != 0 to let the caller > + * know that the sysctl had no effect. Return EAGAIN because a > + * subsequent call will likely succeed (since namei will create > + * a new vnode if necessary) > + */ > + error = EAGAIN; > + goto putvnode; > + } > + > + counter_u64_add(recycles_count, 1); > + vgone(vp); > +putvnode: > + NDFREE(&nd, 0); > +out: > + free(buf, M_TEMP); > + return (error); > +} > + > +static int > +sysctl_ftry_reclaim_vnode(SYSCTL_HANDLER_ARGS) > +{ > + struct thread *td = curthread; > + struct vnode *vp; > + struct file *fp; > + int error; > + int fd; > + > + if (req->newptr == NULL) > + return (EBADF); > + > + error = sysctl_handle_int(oidp, &fd, 0, req); > + if (error != 0) > + return (error); > + error = getvnode(curthread, fd, &cap_fcntl_rights, &fp); > + if (error != 0) > + return (error); > + vp = fp->f_vnode; > + > + error = vn_lock(vp, LK_EXCLUSIVE); > + if (error != 0) > + goto drop; > + > + counter_u64_add(recycles_count, 1); > + vgone(vp); > + VOP_UNLOCK(vp, 0); > +drop: > + fdrop(fp, td); > + return (error); > +} > + > +SYSCTL_PROC(_debug, OID_AUTO, try_reclaim_vnode, > + CTLTYPE_STRING | CTLFLAG_MPSAFE | CTLFLAG_WR, NULL, 0, > + sysctl_try_reclaim_vnode, "A", "Try to reclaim a vnode by its pathname"); > +SYSCTL_PROC(_debug, OID_AUTO, ftry_reclaim_vnode, > + CTLTYPE_INT | CTLFLAG_MPSAFE | CTLFLAG_WR, NULL, 0, > + sysctl_ftry_reclaim_vnode, "I", > + "Try to reclaim a vnode by its file descriptor"); > > /* Shift count for (uintptr_t)vp to initialize vp->v_hash. */ > static int vnsz2log; > > -- Rod Grimes rgri...@freebsd.org _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
