diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c index 7887fe95c863..f6828e1501fa 100644 --- a/sys/kern/vfs_subr.c +++ b/sys/kern/vfs_subr.c @@ -50,6 +50,7 @@ __FBSDID("$FreeBSD$"); #include #include #include +#include #include #include #include @@ -339,6 +340,93 @@ 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;