 @@ -1,1276 +1,1276 @@
-/*	$NetBSD: fss.c,v 1.112 2022/03/31 19:30:15 pgoyette Exp $	*/
+/*	$NetBSD: fss.c,v 1.113 2022/09/24 23:18:54 thorpej Exp $	*/
 /*-
  * Copyright (c) 2003 The NetBSD Foundation, Inc.
  * All rights reserved.
+ *
  * This code is derived from software contributed to The NetBSD Foundation
  * by Juergen Hannken-Illjes.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
+ *
  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  */
 /*
  * File system snapshot disk driver.
+ *
  * Block/character interface to the snapshot of a mounted file system.
  */
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: fss.c,v 1.112 2022/03/31 19:30:15 pgoyette Exp $");
+__KERNEL_RCSID(0, "$NetBSD: fss.c,v 1.113 2022/09/24 23:18:54 thorpej Exp $");
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/namei.h>
 #include <sys/proc.h>
 #include <sys/errno.h>
-#include <sys/malloc.h>
+#include <sys/kmem.h>
 #include <sys/buf.h>
 #include <sys/ioctl.h>
 #include <sys/disklabel.h>
 #include <sys/device.h>
 #include <sys/disk.h>
 #include <sys/stat.h>
 #include <sys/mount.h>
 #include <sys/vnode.h>
 #include <sys/file.h>
 #include <sys/uio.h>
 #include <sys/conf.h>
 #include <sys/kthread.h>
 #include <sys/fstrans.h>
 #include <sys/vfs_syscalls.h>		/* For do_sys_unlink(). */
 #include <miscfs/specfs/specdev.h>
 #include <dev/fssvar.h>
 #include <uvm/uvm.h>
 #include "ioconf.h"
 dev_type_open(fss_open);
 dev_type_close(fss_close);
 dev_type_read(fss_read);
 dev_type_write(fss_write);
 dev_type_ioctl(fss_ioctl);
 dev_type_strategy(fss_strategy);
 dev_type_dump(fss_dump);
 dev_type_size(fss_size);
 static void fss_unmount_hook(struct mount *);
 static int fss_copy_on_write(void *, struct buf *, bool);
 static inline void fss_error(struct fss_softc *, const char *);
 static int fss_create_files(struct fss_softc *, struct fss_set *,
     off_t *, struct lwp *);
 static int fss_create_snapshot(struct fss_softc *, struct fss_set *,
     struct lwp *);
 static int fss_delete_snapshot(struct fss_softc *, struct lwp *);
 static int fss_softc_alloc(struct fss_softc *);
 static void fss_softc_free(struct fss_softc *);
 static int fss_read_cluster(struct fss_softc *, u_int32_t);
 static void fss_bs_thread(void *);
 static int fss_bs_io(struct fss_softc *, fss_io_type,
     u_int32_t, off_t, int, void *, size_t *);
 static u_int32_t *fss_bs_indir(struct fss_softc *, u_int32_t);
 static kmutex_t fss_device_lock;	/* Protect all units. */
 static kcondvar_t fss_device_cv;	/* Serialize snapshot creation. */
 static bool fss_creating = false;	/* Currently creating a snapshot. */
 static int fss_num_attached = 0;	/* Number of attached devices. */
 static struct vfs_hooks fss_vfs_hooks = {
 	.vh_unmount = fss_unmount_hook
 };
 const struct bdevsw fss_bdevsw = {
 	.d_open = fss_open,
 	.d_close = fss_close,
 	.d_strategy = fss_strategy,
 	.d_ioctl = fss_ioctl,
 	.d_dump = fss_dump,
 	.d_psize = fss_size,
 	.d_discard = nodiscard,
 	.d_flag = D_DISK | D_MPSAFE
 };
 const struct cdevsw fss_cdevsw = {
 	.d_open = fss_open,
 	.d_close = fss_close,
 	.d_read = fss_read,
 	.d_write = fss_write,
 	.d_ioctl = fss_ioctl,
 	.d_stop = nostop,
 	.d_tty = notty,
 	.d_poll = nopoll,
 	.d_mmap = nommap,
 	.d_kqfilter = nokqfilter,
 	.d_discard = nodiscard,
 	.d_flag = D_DISK | D_MPSAFE
 };
 static int fss_match(device_t, cfdata_t, void *);
 static void fss_attach(device_t, device_t, void *);
 static int fss_detach(device_t, int);
 CFATTACH_DECL_NEW(fss, sizeof(struct fss_softc),
     fss_match, fss_attach, fss_detach, NULL);
 void
 fssattach(int num)
+{
 	mutex_init(&fss_device_lock, MUTEX_DEFAULT, IPL_NONE);
 	cv_init(&fss_device_cv, "snapwait");
 	if (config_cfattach_attach(fss_cd.cd_name, &fss_ca))
 		aprint_error("%s: unable to register\n", fss_cd.cd_name);
+}
 static int
 fss_match(device_t self, cfdata_t cfdata, void *aux)
+{
 	return 1;
+}
 static void
 fss_attach(device_t parent, device_t self, void *aux)
+{
 	struct fss_softc *sc = device_private(self);
 	sc->sc_dev = self;
 	sc->sc_bdev = NODEV;
 	mutex_init(&sc->sc_slock, MUTEX_DEFAULT, IPL_NONE);
 	cv_init(&sc->sc_work_cv, "fssbs");
 	cv_init(&sc->sc_cache_cv, "cowwait");
 	bufq_alloc(&sc->sc_bufq, "fcfs", 0);
-	sc->sc_dkdev = malloc(sizeof(*sc->sc_dkdev), M_DEVBUF, M_WAITOK);
+	sc->sc_dkdev = kmem_zalloc(sizeof(*sc->sc_dkdev), KM_SLEEP);
 	sc->sc_dkdev->dk_info = NULL;
 	disk_init(sc->sc_dkdev, device_xname(self), NULL);
 	if (!pmf_device_register(self, NULL, NULL))
 		aprint_error_dev(self, "couldn't establish power handler\n");
 	if (fss_num_attached++ == 0)
 		vfs_hooks_attach(&fss_vfs_hooks);
+}
 static int
 fss_detach(device_t self, int flags)
+{
 	struct fss_softc *sc = device_private(self);
 	mutex_enter(&sc->sc_slock);
 	if (sc->sc_state != FSS_IDLE) {
 		mutex_exit(&sc->sc_slock);
 		return EBUSY;
+	}
 	mutex_exit(&sc->sc_slock);
 	if (--fss_num_attached == 0)
 		vfs_hooks_detach(&fss_vfs_hooks);
 	pmf_device_deregister(self);
 	mutex_destroy(&sc->sc_slock);
 	cv_destroy(&sc->sc_work_cv);
 	cv_destroy(&sc->sc_cache_cv);
 	bufq_drain(sc->sc_bufq);
 	bufq_free(sc->sc_bufq);
 	disk_destroy(sc->sc_dkdev);
-	free(sc->sc_dkdev, M_DEVBUF);
+	kmem_free(sc->sc_dkdev, sizeof(*sc->sc_dkdev));
 	return 0;
+}
 int
 fss_open(dev_t dev, int flags, int mode, struct lwp *l)
+{
 	int mflag;
 	cfdata_t cf;
 	struct fss_softc *sc;
 	mflag = (mode == S_IFCHR ? FSS_CDEV_OPEN : FSS_BDEV_OPEN);
 	mutex_enter(&fss_device_lock);
 	sc = device_lookup_private(&fss_cd, minor(dev));
 	if (sc == NULL) {
-		cf = malloc(sizeof(*cf), M_DEVBUF, M_WAITOK);
+		cf = kmem_zalloc(sizeof(*cf), KM_SLEEP);
 		cf->cf_name = fss_cd.cd_name;
 		cf->cf_atname = fss_cd.cd_name;
 		cf->cf_unit = minor(dev);
 		cf->cf_fstate = FSTATE_STAR;
 		sc = device_private(config_attach_pseudo(cf));
 		if (sc == NULL) {
 			mutex_exit(&fss_device_lock);
 			return ENOMEM;
+		}
 		sc->sc_state = FSS_IDLE;
+	}
 	mutex_enter(&sc->sc_slock);
 	sc->sc_flags |= mflag;
 	mutex_exit(&sc->sc_slock);
 	mutex_exit(&fss_device_lock);
 	return 0;
+}
 int
 fss_close(dev_t dev, int flags, int mode, struct lwp *l)
+{
 	int mflag, error;
 	cfdata_t cf;
 	struct fss_softc *sc = device_lookup_private(&fss_cd, minor(dev));
 	if (sc == NULL)
 		return ENXIO;
 	mflag = (mode == S_IFCHR ? FSS_CDEV_OPEN : FSS_BDEV_OPEN);
 	error = 0;
 	mutex_enter(&fss_device_lock);
 restart:
 	mutex_enter(&sc->sc_slock);
 	if ((sc->sc_flags & (FSS_CDEV_OPEN|FSS_BDEV_OPEN)) != mflag) {
 		sc->sc_flags &= ~mflag;
 		mutex_exit(&sc->sc_slock);
 		mutex_exit(&fss_device_lock);
 		return 0;
+	}
 	if (sc->sc_state != FSS_IDLE &&
 	    (sc->sc_uflags & FSS_UNCONFIG_ON_CLOSE) != 0) {
 		sc->sc_uflags &= ~FSS_UNCONFIG_ON_CLOSE;
 		mutex_exit(&sc->sc_slock);
 		error = fss_ioctl(dev, FSSIOCCLR, NULL, FWRITE, l);
 		goto restart;
+	}
 	if (sc->sc_state != FSS_IDLE) {
 		mutex_exit(&sc->sc_slock);
 		mutex_exit(&fss_device_lock);
 		return error;
+	}
 	KASSERT(sc->sc_state == FSS_IDLE);
 	KASSERT((sc->sc_flags & (FSS_CDEV_OPEN|FSS_BDEV_OPEN)) == mflag);
 	mutex_exit(&sc->sc_slock);
 	cf = device_cfdata(sc->sc_dev);
 	error = config_detach(sc->sc_dev, DETACH_QUIET);
 	if (! error)
-		free(cf, M_DEVBUF);
+		kmem_free(cf, sizeof(*cf));
 	mutex_exit(&fss_device_lock);
 	return error;
+}
 void
 fss_strategy(struct buf *bp)
+{
 	const bool write = ((bp->b_flags & B_READ) != B_READ);
 	struct fss_softc *sc = device_lookup_private(&fss_cd, minor(bp->b_dev));
 	if (sc == NULL) {
 		bp->b_error = ENXIO;
 		goto done;
+	}
 	mutex_enter(&sc->sc_slock);
 	if (write || sc->sc_state != FSS_ACTIVE) {
 		bp->b_error = (write ? EROFS : ENXIO);
 		goto done;
+	}
 	/* Check bounds for non-persistent snapshots. */
 	if ((sc->sc_flags & FSS_PERSISTENT) == 0 &&
 	    bounds_check_with_mediasize(bp, DEV_BSIZE,
 	    btodb(FSS_CLTOB(sc, sc->sc_clcount - 1) + sc->sc_clresid)) <= 0)
 		goto done;
 	bp->b_rawblkno = bp->b_blkno;
 	bufq_put(sc->sc_bufq, bp);
 	cv_signal(&sc->sc_work_cv);
 	mutex_exit(&sc->sc_slock);
 	return;
 done:
 	if (sc != NULL)
 		mutex_exit(&sc->sc_slock);
 	bp->b_resid = bp->b_bcount;
 	biodone(bp);
+}
 int
 fss_read(dev_t dev, struct uio *uio, int flags)
+{
 	return physio(fss_strategy, NULL, dev, B_READ, minphys, uio);
+}
 int
 fss_write(dev_t dev, struct uio *uio, int flags)
+{
 	return physio(fss_strategy, NULL, dev, B_WRITE, minphys, uio);
+}
 int
 fss_ioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
+{
 	int error = 0;
 	struct fss_softc *sc = device_lookup_private(&fss_cd, minor(dev));
 	struct fss_set _fss;
 	struct fss_set *fss = (struct fss_set *)data;
 	struct fss_set50 *fss50 = (struct fss_set50 *)data;
 	struct fss_get *fsg = (struct fss_get *)data;
 #ifndef _LP64
 	struct fss_get50 *fsg50 = (struct fss_get50 *)data;
 #endif
 	if (sc == NULL)
 		return ENXIO;
 	switch (cmd) {
 	case FSSIOCSET50:
 		fss = &_fss;
 		fss->fss_mount = fss50->fss_mount;
 		fss->fss_bstore = fss50->fss_bstore;
 		fss->fss_csize = fss50->fss_csize;
 		fss->fss_flags = 0;
 		/* Fall through */
 	case FSSIOCSET:
 		mutex_enter(&sc->sc_slock);
 		if ((flag & FWRITE) == 0)
 			error = EPERM;
 		if (error == 0 && sc->sc_state != FSS_IDLE) {
 			error = EBUSY;
 		} else {
 			sc->sc_state = FSS_CREATING;
 			copyinstr(fss->fss_mount, sc->sc_mntname,
 			    sizeof(sc->sc_mntname), NULL);
 			memset(&sc->sc_time, 0, sizeof(sc->sc_time));
 			sc->sc_clshift = 0;
+		}
 		mutex_exit(&sc->sc_slock);
 		if (error)
 			break;
 		/*
 		 * Serialize snapshot creation.
 		 */
 		mutex_enter(&fss_device_lock);
 		while (fss_creating) {
 			error = cv_wait_sig(&fss_device_cv, &fss_device_lock);
 			if (error) {
 				mutex_enter(&sc->sc_slock);
 				KASSERT(sc->sc_state == FSS_CREATING);
 				sc->sc_state = FSS_IDLE;
 				mutex_exit(&sc->sc_slock);
 				mutex_exit(&fss_device_lock);
 				break;
+			}
+		}
 		fss_creating = true;
 		mutex_exit(&fss_device_lock);
 		error = fss_create_snapshot(sc, fss, l);
 		mutex_enter(&sc->sc_slock);
 		if (error == 0) {
 			KASSERT(sc->sc_state == FSS_ACTIVE);
 			sc->sc_uflags = fss->fss_flags;
 		} else {
 			KASSERT(sc->sc_state == FSS_CREATING);
 			sc->sc_state = FSS_IDLE;
+		}
 		mutex_exit(&sc->sc_slock);
 		mutex_enter(&fss_device_lock);
 		fss_creating = false;
 		cv_broadcast(&fss_device_cv);
 		mutex_exit(&fss_device_lock);
 		break;
 	case FSSIOCCLR:
 		mutex_enter(&sc->sc_slock);
 		if ((flag & FWRITE) == 0) {
 			error = EPERM;
 		} else if (sc->sc_state != FSS_ACTIVE) {
 			error = EBUSY;
 		} else {
 			sc->sc_state = FSS_DESTROYING;
+		}
 		mutex_exit(&sc->sc_slock);
 		if (error)
 			break;
 		error = fss_delete_snapshot(sc, l);
 		mutex_enter(&sc->sc_slock);
 		if (error)
 			fss_error(sc, "Failed to delete snapshot");
 		else
 			KASSERT(sc->sc_state == FSS_IDLE);
 		mutex_exit(&sc->sc_slock);
 		break;
 #ifndef _LP64
 	case FSSIOCGET50:
 		mutex_enter(&sc->sc_slock);
 		if (sc->sc_state == FSS_IDLE) {
 			error = ENXIO;
 		} else if ((sc->sc_flags & FSS_PERSISTENT) == 0) {
 			memcpy(fsg50->fsg_mount, sc->sc_mntname, MNAMELEN);
 			fsg50->fsg_csize = FSS_CLSIZE(sc);
 			timeval_to_timeval50(&sc->sc_time, &fsg50->fsg_time);
 			fsg50->fsg_mount_size = sc->sc_clcount;
 			fsg50->fsg_bs_size = sc->sc_clnext;
 			error = 0;
 		} else {
 			memcpy(fsg50->fsg_mount, sc->sc_mntname, MNAMELEN);
 			fsg50->fsg_csize = 0;
 			timeval_to_timeval50(&sc->sc_time, &fsg50->fsg_time);
 			fsg50->fsg_mount_size = 0;
 			fsg50->fsg_bs_size = 0;
 			error = 0;
+		}
 		mutex_exit(&sc->sc_slock);
 		break;
 #endif /* _LP64 */
 	case FSSIOCGET:
 		mutex_enter(&sc->sc_slock);
 		if (sc->sc_state == FSS_IDLE) {
 			error = ENXIO;
 		} else if ((sc->sc_flags & FSS_PERSISTENT) == 0) {
 			memcpy(fsg->fsg_mount, sc->sc_mntname, MNAMELEN);
 			fsg->fsg_csize = FSS_CLSIZE(sc);
 			fsg->fsg_time = sc->sc_time;
 			fsg->fsg_mount_size = sc->sc_clcount;
 			fsg->fsg_bs_size = sc->sc_clnext;
 			error = 0;
 		} else {
 			memcpy(fsg->fsg_mount, sc->sc_mntname, MNAMELEN);
 			fsg->fsg_csize = 0;
 			fsg->fsg_time = sc->sc_time;
 			fsg->fsg_mount_size = 0;
 			fsg->fsg_bs_size = 0;
 			error = 0;
+		}
 		mutex_exit(&sc->sc_slock);
 		break;
 	case FSSIOFSET:
 		mutex_enter(&sc->sc_slock);
 		sc->sc_uflags = *(int *)data;
 		mutex_exit(&sc->sc_slock);
 		error = 0;
 		break;
 	case FSSIOFGET:
 		mutex_enter(&sc->sc_slock);
 		*(int *)data = sc->sc_uflags;
 		mutex_exit(&sc->sc_slock);
 		error = 0;
 		break;
 	default:
 		error = EINVAL;
 		break;
+	}
 	return error;
+}
 int
 fss_size(dev_t dev)
+{
 	return -1;
+}
 int
 fss_dump(dev_t dev, daddr_t blkno, void *va,
     size_t size)
+{
 	return EROFS;
+}
 /*
  * An error occurred reading or writing the snapshot or backing store.
  * If it is the first error log to console and disestablish cow handler.
  * The caller holds the mutex.
  */
 static inline void
 fss_error(struct fss_softc *sc, const char *msg)
+{
 	KASSERT(mutex_owned(&sc->sc_slock));
 	if ((sc->sc_flags & FSS_ERROR))
 		return;
 	aprint_error_dev(sc->sc_dev, "snapshot invalid: %s\n", msg);
 	if ((sc->sc_flags & FSS_PERSISTENT) == 0) {
 		mutex_exit(&sc->sc_slock);
 		fscow_disestablish(sc->sc_mount, fss_copy_on_write, sc);
 		mutex_enter(&sc->sc_slock);
+	}
 	sc->sc_flags |= FSS_ERROR;
+}
 /*
  * Allocate the variable sized parts of the softc and
  * fork the kernel thread.
+ *
  * The fields sc_clcount, sc_clshift, sc_cache_size and sc_indir_size
  * must be initialized.
  */
 static int
 fss_softc_alloc(struct fss_softc *sc)
+{
 	int i, error;
 	if ((sc->sc_flags & FSS_PERSISTENT) == 0) {
 		sc->sc_copied =
 		    kmem_zalloc(howmany(sc->sc_clcount, NBBY), KM_SLEEP);
 		sc->sc_cache = kmem_alloc(sc->sc_cache_size *
 		    sizeof(struct fss_cache), KM_SLEEP);
 		for (i = 0; i < sc->sc_cache_size; i++) {
 			sc->sc_cache[i].fc_type = FSS_CACHE_FREE;
 			sc->sc_cache[i].fc_data =
 			    kmem_alloc(FSS_CLSIZE(sc), KM_SLEEP);
 			cv_init(&sc->sc_cache[i].fc_state_cv, "cowwait1");
+		}
 		sc->sc_indir_valid =
 		    kmem_zalloc(howmany(sc->sc_indir_size, NBBY), KM_SLEEP);
 		sc->sc_indir_data = kmem_zalloc(FSS_CLSIZE(sc), KM_SLEEP);
 	} else {
 		sc->sc_copied = NULL;
 		sc->sc_cache = NULL;
 		sc->sc_indir_valid = NULL;
 		sc->sc_indir_data = NULL;
+	}
 	sc->sc_flags |= FSS_BS_THREAD;
 	if ((error = kthread_create(PRI_BIO, KTHREAD_MUSTJOIN, NULL,
 	    fss_bs_thread, sc, &sc->sc_bs_lwp,
 	    "%s", device_xname(sc->sc_dev))) != 0) {
 		sc->sc_flags &= ~FSS_BS_THREAD;
 		return error;
+	}
 	disk_attach(sc->sc_dkdev);
 	return 0;
+}
 /*
  * Free the variable sized parts of the softc.
  */
 static void
 fss_softc_free(struct fss_softc *sc)
+{
 	int i;
 	if ((sc->sc_flags & FSS_BS_THREAD) != 0) {
 		mutex_enter(&sc->sc_slock);
 		sc->sc_flags &= ~FSS_BS_THREAD;
 		cv_signal(&sc->sc_work_cv);
 		mutex_exit(&sc->sc_slock);
 		kthread_join(sc->sc_bs_lwp);
 		disk_detach(sc->sc_dkdev);
+	}
 	if (sc->sc_copied != NULL)
 		kmem_free(sc->sc_copied, howmany(sc->sc_clcount, NBBY));
 	sc->sc_copied = NULL;
 	if (sc->sc_cache != NULL) {
 		for (i = 0; i < sc->sc_cache_size; i++)
 			if (sc->sc_cache[i].fc_data != NULL) {
 				cv_destroy(&sc->sc_cache[i].fc_state_cv);
 				kmem_free(sc->sc_cache[i].fc_data,
 				    FSS_CLSIZE(sc));
+			}
 		kmem_free(sc->sc_cache,
 		    sc->sc_cache_size*sizeof(struct fss_cache));
+	}
 	sc->sc_cache = NULL;
 	if (sc->sc_indir_valid != NULL)
 		kmem_free(sc->sc_indir_valid, howmany(sc->sc_indir_size, NBBY));
 	sc->sc_indir_valid = NULL;
 	if (sc->sc_indir_data != NULL)
 		kmem_free(sc->sc_indir_data, FSS_CLSIZE(sc));
 	sc->sc_indir_data = NULL;
+}
 /*
  * Set all active snapshots on this file system into ERROR state.
  */
 static void
 fss_unmount_hook(struct mount *mp)
+{
 	int i;
 	struct fss_softc *sc;
 	mutex_enter(&fss_device_lock);
 	for (i = 0; i < fss_cd.cd_ndevs; i++) {
 		if ((sc = device_lookup_private(&fss_cd, i)) == NULL)
 			continue;
 		mutex_enter(&sc->sc_slock);
 		if (sc->sc_state != FSS_IDLE && sc->sc_mount == mp)
 			fss_error(sc, "forced by unmount");
 		mutex_exit(&sc->sc_slock);
+	}
 	mutex_exit(&fss_device_lock);
+}
 /*
  * A buffer is written to the snapshotted block device. Copy to
  * backing store if needed.
  */
 static int
 fss_copy_on_write(void *v, struct buf *bp, bool data_valid)
+{
 	int error;
 	u_int32_t cl, ch, c;
 	struct fss_softc *sc = v;
 	mutex_enter(&sc->sc_slock);
 	if (sc->sc_state != FSS_ACTIVE) {
 		mutex_exit(&sc->sc_slock);
 		return 0;
+	}
 	cl = FSS_BTOCL(sc, dbtob(bp->b_blkno));
 	ch = FSS_BTOCL(sc, dbtob(bp->b_blkno)+bp->b_bcount-1);
 	error = 0;
 	if (curlwp == uvm.pagedaemon_lwp) {
 		for (c = cl; c <= ch; c++)
 			if (isclr(sc->sc_copied, c)) {
 				error = ENOMEM;
 				break;
+			}
+	}
 	mutex_exit(&sc->sc_slock);
 	if (error == 0)
 		for (c = cl; c <= ch; c++) {
 			error = fss_read_cluster(sc, c);
 			if (error)
 				break;
+		}
 	return error;
+}
 /*
  * Lookup and open needed files.
+ *
  * For file system internal snapshot initializes sc_mntname, sc_mount,
  * sc_bs_vp and sc_time.
+ *
  * Otherwise returns dev and size of the underlying block device.
  * Initializes sc_mntname, sc_mount, sc_bdev, sc_bs_vp and sc_mount
  */
 static int
 fss_create_files(struct fss_softc *sc, struct fss_set *fss,
     off_t *bsize, struct lwp *l)
+{
 	int error, bits, fsbsize;
 	uint64_t numsec;
 	unsigned int secsize;
 	struct timespec ts;
 	/* distinguish lookup 1 from lookup 2 to reduce mistakes */
 	struct pathbuf *pb2;
 	struct vnode *vp, *vp2;
 	/*
 	 * Get the mounted file system.
 	 */
 	error = namei_simple_user(fss->fss_mount,
 				NSM_FOLLOW_NOEMULROOT, &vp);
 	if (error != 0)
 		return error;
 	if ((vp->v_vflag & VV_ROOT) != VV_ROOT) {
 		vrele(vp);
 		return EINVAL;
+	}
 	sc->sc_mount = vp->v_mount;
 	memcpy(sc->sc_mntname, sc->sc_mount->mnt_stat.f_mntonname, MNAMELEN);
 	vrele(vp);
 	/*
 	 * Check for file system internal snapshot.
 	 */
 	error = namei_simple_user(fss->fss_bstore,
 				NSM_FOLLOW_NOEMULROOT, &vp);
 	if (error != 0)
 		return error;
 	if (vp->v_type == VREG && vp->v_mount == sc->sc_mount) {
 		sc->sc_flags |= FSS_PERSISTENT;
 		sc->sc_bs_vp = vp;
 		fsbsize = sc->sc_bs_vp->v_mount->mnt_stat.f_iosize;
 		bits = sizeof(sc->sc_bs_bshift)*NBBY;
 		for (sc->sc_bs_bshift = 1; sc->sc_bs_bshift < bits;
 		    sc->sc_bs_bshift++)
 			if (FSS_FSBSIZE(sc) == fsbsize)
 				break;
 		if (sc->sc_bs_bshift >= bits)
 			return EINVAL;
 		sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1;
 		sc->sc_clshift = 0;
 		if ((fss->fss_flags & FSS_UNLINK_ON_CREATE) != 0) {
 			error = do_sys_unlink(fss->fss_bstore, UIO_USERSPACE);
 			if (error)
 				return error;
+		}
 		error = vn_lock(vp, LK_EXCLUSIVE);
 		if (error != 0)
 			return error;
 		error = VFS_SNAPSHOT(sc->sc_mount, sc->sc_bs_vp, &ts);
 		TIMESPEC_TO_TIMEVAL(&sc->sc_time, &ts);
 		VOP_UNLOCK(sc->sc_bs_vp);
 		return error;
+	}
 	vrele(vp);
 	/*
 	 * Get the block device it is mounted on and its size.
 	 */
 	error = spec_node_lookup_by_mount(sc->sc_mount, &vp);
 	if (error)
 		return error;
 	sc->sc_bdev = vp->v_rdev;
 	error = getdisksize(vp, &numsec, &secsize);
 	vrele(vp);
 	if (error)
 		return error;
 	*bsize = (off_t)numsec*secsize;
 	/*
 	 * Get the backing store
 	 */
 	error = pathbuf_copyin(fss->fss_bstore, &pb2);
 	if (error) {
  		return error;
+	}
 	error = vn_open(NULL, pb2, 0, FREAD|FWRITE, 0, &vp2, NULL, NULL);
 	if (error != 0) {
 		pathbuf_destroy(pb2);
 		return error;
+	}
 	VOP_UNLOCK(vp2);
 	sc->sc_bs_vp = vp2;
 	if (vp2->v_type != VREG && vp2->v_type != VCHR) {
 		vrele(vp2);
 		pathbuf_destroy(pb2);
 		return EINVAL;
+	}
 	pathbuf_destroy(pb2);
 	if ((fss->fss_flags & FSS_UNLINK_ON_CREATE) != 0) {
 		error = do_sys_unlink(fss->fss_bstore, UIO_USERSPACE);
 		if (error)
 			return error;
+	}
 	if (sc->sc_bs_vp->v_type == VREG) {
 		fsbsize = sc->sc_bs_vp->v_mount->mnt_stat.f_iosize;
 		if (fsbsize & (fsbsize-1))	/* No power of two */
 			return EINVAL;
 		for (sc->sc_bs_bshift = 1; sc->sc_bs_bshift < 32;
 		    sc->sc_bs_bshift++)
 			if (FSS_FSBSIZE(sc) == fsbsize)
 				break;
 		if (sc->sc_bs_bshift >= 32)
 			return EINVAL;
 		sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1;
 	} else {
 		sc->sc_bs_bshift = DEV_BSHIFT;
 		sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1;
+	}
 	return 0;
+}
 /*
  * Create a snapshot.
  */
 static int
 fss_create_snapshot(struct fss_softc *sc, struct fss_set *fss, struct lwp *l)
+{
 	int len, error;
 	u_int32_t csize;
 	off_t bsize;
 	bsize = 0;	/* XXX gcc */
 	/*
 	 * Open needed files.
 	 */
 	if ((error = fss_create_files(sc, fss, &bsize, l)) != 0)
 		goto bad;
 	if (sc->sc_flags & FSS_PERSISTENT) {
 		fss_softc_alloc(sc);
 		mutex_enter(&sc->sc_slock);
 		sc->sc_state = FSS_ACTIVE;
 		mutex_exit(&sc->sc_slock);
 		return 0;
+	}
 	/*
 	 * Set cluster size. Must be a power of two and
 	 * a multiple of backing store block size.
 	 */
 	if (fss->fss_csize <= 0)
 		csize = MAXPHYS;
 	else
 		csize = fss->fss_csize;
 	if (bsize/csize > FSS_CLUSTER_MAX)
 		csize = bsize/FSS_CLUSTER_MAX+1;
 	for (sc->sc_clshift = sc->sc_bs_bshift; sc->sc_clshift < 32;
 	    sc->sc_clshift++)
 		if (FSS_CLSIZE(sc) >= csize)
 			break;
 	if (sc->sc_clshift >= 32) {
 		error = EINVAL;
 		goto bad;
+	}
 	sc->sc_clmask = FSS_CLSIZE(sc)-1;
 	/*
 	 * Set number of cache slots.
 	 */
 	if (FSS_CLSIZE(sc) <= 8192)
 		sc->sc_cache_size = 32;
 	else if (FSS_CLSIZE(sc) <= 65536)
 		sc->sc_cache_size = 8;
 	else
 		sc->sc_cache_size = 4;
 	/*
 	 * Set number of clusters and size of last cluster.
 	 */
 	sc->sc_clcount = FSS_BTOCL(sc, bsize-1)+1;
 	sc->sc_clresid = FSS_CLOFF(sc, bsize-1)+1;
 	/*
 	 * Set size of indirect table.
 	 */
 	len = sc->sc_clcount*sizeof(u_int32_t);
 	sc->sc_indir_size = FSS_BTOCL(sc, len)+1;
 	sc->sc_clnext = sc->sc_indir_size;
 	sc->sc_indir_cur = 0;
 	if ((error = fss_softc_alloc(sc)) != 0)
 		goto bad;
 	/*
 	 * Activate the snapshot.
 	 */
 	if ((error = vfs_suspend(sc->sc_mount, 0)) != 0)
 		goto bad;
 	microtime(&sc->sc_time);
 	vrele_flush(sc->sc_mount);
 	error = VFS_SYNC(sc->sc_mount, MNT_WAIT, curlwp->l_cred);
 	if (error == 0)
 		error = fscow_establish(sc->sc_mount, fss_copy_on_write, sc);
 	if (error == 0) {
 		mutex_enter(&sc->sc_slock);
 		sc->sc_state = FSS_ACTIVE;
 		mutex_exit(&sc->sc_slock);
+	}
 	vfs_resume(sc->sc_mount);
 	if (error != 0)
 		goto bad;
 	aprint_debug_dev(sc->sc_dev, "%s snapshot active\n", sc->sc_mntname);
 	aprint_debug_dev(sc->sc_dev,
 	    "%u clusters of %u, %u cache slots, %u indir clusters\n",
 	    sc->sc_clcount, FSS_CLSIZE(sc),
 	    sc->sc_cache_size, sc->sc_indir_size);
 	return 0;
 bad:
 	fss_softc_free(sc);
 	if (sc->sc_bs_vp != NULL) {
 		if (sc->sc_flags & FSS_PERSISTENT)
 			vrele(sc->sc_bs_vp);
 		else
 			vn_close(sc->sc_bs_vp, FREAD|FWRITE, l->l_cred);
+	}
 	sc->sc_bs_vp = NULL;
 	return error;
+}
 /*
  * Delete a snapshot.
  */
 static int
 fss_delete_snapshot(struct fss_softc *sc, struct lwp *l)
+{
 	mutex_enter(&sc->sc_slock);
 	if ((sc->sc_flags & FSS_PERSISTENT) == 0 &&
 	    (sc->sc_flags & FSS_ERROR) == 0) {
 		mutex_exit(&sc->sc_slock);
 		fscow_disestablish(sc->sc_mount, fss_copy_on_write, sc);
 	} else {
 		mutex_exit(&sc->sc_slock);
+	}
 	fss_softc_free(sc);
 	if (sc->sc_flags & FSS_PERSISTENT)
 		vrele(sc->sc_bs_vp);
 	else
 		vn_close(sc->sc_bs_vp, FREAD|FWRITE, l->l_cred);
 	mutex_enter(&sc->sc_slock);
 	sc->sc_state = FSS_IDLE;
 	sc->sc_mount = NULL;
 	sc->sc_bdev = NODEV;
 	sc->sc_bs_vp = NULL;
 	sc->sc_flags &= ~FSS_PERSISTENT;
 	mutex_exit(&sc->sc_slock);
 	return 0;
+}
 /*
  * Read a cluster from the snapshotted block device to the cache.
  */
 static int
 fss_read_cluster(struct fss_softc *sc, u_int32_t cl)
+{
 	int error, todo, offset, len;
 	daddr_t dblk;
 	struct buf *bp, *mbp;
 	struct fss_cache *scp, *scl;
 	/*
 	 * Get a free cache slot.
 	 */
 	scl = sc->sc_cache+sc->sc_cache_size;
 	mutex_enter(&sc->sc_slock);
 restart:
 	if (isset(sc->sc_copied, cl) || sc->sc_state != FSS_ACTIVE) {
 		mutex_exit(&sc->sc_slock);
 		return 0;
+	}
 	for (scp = sc->sc_cache; scp < scl; scp++) {
 		if (scp->fc_type == FSS_CACHE_VALID) {
 			if (scp->fc_cluster == cl) {
 				mutex_exit(&sc->sc_slock);
 				return 0;
+			}
 		} else if (scp->fc_type == FSS_CACHE_BUSY) {
 			if (scp->fc_cluster == cl) {
 				cv_wait(&scp->fc_state_cv, &sc->sc_slock);
 				goto restart;
+			}
+		}
+	}
 	for (scp = sc->sc_cache; scp < scl; scp++)
 		if (scp->fc_type == FSS_CACHE_FREE) {
 			scp->fc_type = FSS_CACHE_BUSY;
 			scp->fc_cluster = cl;
 			break;
+		}
 	if (scp >= scl) {
 		cv_wait(&sc->sc_cache_cv, &sc->sc_slock);
 		goto restart;
+	}
 	mutex_exit(&sc->sc_slock);
 	/*
 	 * Start the read.
 	 */
 	dblk = btodb(FSS_CLTOB(sc, cl));
 	if (cl == sc->sc_clcount-1) {
 		todo = sc->sc_clresid;
 		memset((char *)scp->fc_data + todo, 0, FSS_CLSIZE(sc) - todo);
 	} else
 		todo = FSS_CLSIZE(sc);
 	offset = 0;
 	mbp = getiobuf(NULL, true);
 	mbp->b_bufsize = todo;
 	mbp->b_data = scp->fc_data;
 	mbp->b_resid = mbp->b_bcount = todo;
 	mbp->b_flags = B_READ;
 	mbp->b_cflags = BC_BUSY;
 	mbp->b_dev = sc->sc_bdev;
 	while (todo > 0) {
 		len = todo;
 		if (len > MAXPHYS)
 			len = MAXPHYS;
 		if (btodb(FSS_CLTOB(sc, cl)) == dblk && len == todo)
 			bp = mbp;
 		else {
 			bp = getiobuf(NULL, true);
 			nestiobuf_setup(mbp, bp, offset, len);
+		}
 		bp->b_lblkno = 0;
 		bp->b_blkno = dblk;
 		bdev_strategy(bp);
 		dblk += btodb(len);
 		offset += len;
 		todo -= len;
+	}
 	error = biowait(mbp);
 	if (error == 0 && mbp->b_resid != 0)
 		error = EIO;
 	putiobuf(mbp);
 	mutex_enter(&sc->sc_slock);
 	scp->fc_type = (error ? FSS_CACHE_FREE : FSS_CACHE_VALID);
 	cv_broadcast(&scp->fc_state_cv);
 	if (error == 0) {
 		setbit(sc->sc_copied, scp->fc_cluster);
 		cv_signal(&sc->sc_work_cv);
+	}
 	mutex_exit(&sc->sc_slock);
 	return error;
+}
 /*
  * Read/write clusters from/to backing store.
  * For persistent snapshots must be called with cl == 0. off is the
  * offset into the snapshot.
  */
 static int
 fss_bs_io(struct fss_softc *sc, fss_io_type rw,
     u_int32_t cl, off_t off, int len, void *data, size_t *resid)
+{
 	int error;
 	off += FSS_CLTOB(sc, cl);
 	vn_lock(sc->sc_bs_vp, LK_EXCLUSIVE|LK_RETRY);
 	error = vn_rdwr((rw == FSS_READ ? UIO_READ : UIO_WRITE), sc->sc_bs_vp,
 	    data, len, off, UIO_SYSSPACE,
 	    IO_ADV_ENCODE(POSIX_FADV_NOREUSE) | IO_NODELOCKED,
 	    sc->sc_bs_lwp->l_cred, resid, NULL);
 	if (error == 0) {
 		rw_enter(sc->sc_bs_vp->v_uobj.vmobjlock, RW_WRITER);
 		error = VOP_PUTPAGES(sc->sc_bs_vp, trunc_page(off),
 		    round_page(off+len), PGO_CLEANIT | PGO_FREE | PGO_SYNCIO);
+	}
 	VOP_UNLOCK(sc->sc_bs_vp);
 	return error;
+}
 /*
  * Get a pointer to the indirect slot for this cluster.
  */
 static u_int32_t *
 fss_bs_indir(struct fss_softc *sc, u_int32_t cl)
+{
 	u_int32_t icl;
 	int ioff;
 	icl = cl/(FSS_CLSIZE(sc)/sizeof(u_int32_t));
 	ioff = cl%(FSS_CLSIZE(sc)/sizeof(u_int32_t));
 	if (sc->sc_indir_cur == icl)
 		return &sc->sc_indir_data[ioff];
 	if (sc->sc_indir_dirty) {
 		if (fss_bs_io(sc, FSS_WRITE, sc->sc_indir_cur, 0,
 		    FSS_CLSIZE(sc), (void *)sc->sc_indir_data, NULL) != 0)
 			return NULL;
 		setbit(sc->sc_indir_valid, sc->sc_indir_cur);
+	}
 	sc->sc_indir_dirty = 0;
 	sc->sc_indir_cur = icl;
 	if (isset(sc->sc_indir_valid, sc->sc_indir_cur)) {
 		if (fss_bs_io(sc, FSS_READ, sc->sc_indir_cur, 0,
 		    FSS_CLSIZE(sc), (void *)sc->sc_indir_data, NULL) != 0)
 			return NULL;
 	} else
 		memset(sc->sc_indir_data, 0, FSS_CLSIZE(sc));
 	return &sc->sc_indir_data[ioff];
+}
 /*
  * The kernel thread (one for every active snapshot).
+ *
  * After wakeup it cleans the cache and runs the I/O requests.
  */
 static void
 fss_bs_thread(void *arg)
+{
 	bool thread_idle, is_valid;
 	int error, i, todo, len, crotor, is_read;
 	long off;
 	char *addr;
 	u_int32_t c, cl, ch, *indirp;
 	size_t resid;
 	struct buf *bp, *nbp;
 	struct fss_softc *sc;
 	struct fss_cache *scp, *scl;
 	sc = arg;
 	scl = sc->sc_cache+sc->sc_cache_size;
 	crotor = 0;
 	thread_idle = false;
 	mutex_enter(&sc->sc_slock);
 	for (;;) {
 		if (thread_idle)
 			cv_wait(&sc->sc_work_cv, &sc->sc_slock);
 		thread_idle = true;
 		if ((sc->sc_flags & FSS_BS_THREAD) == 0) {
 			mutex_exit(&sc->sc_slock);
 			kthread_exit(0);
+		}
 		/*
 		 * Process I/O requests (persistent)
 		 */
 		if (sc->sc_flags & FSS_PERSISTENT) {
 			if ((bp = bufq_get(sc->sc_bufq)) == NULL)
 				continue;
 			is_valid = (sc->sc_state == FSS_ACTIVE);
 			is_read = (bp->b_flags & B_READ);
 			thread_idle = false;
 			mutex_exit(&sc->sc_slock);
 			if (is_valid) {
 				disk_busy(sc->sc_dkdev);
 				error = fss_bs_io(sc, FSS_READ, 0,
 				    dbtob(bp->b_blkno), bp->b_bcount,
 				    bp->b_data, &resid);
 				if (error)
 					resid = bp->b_bcount;
 				disk_unbusy(sc->sc_dkdev,
 				    (error ? 0 : bp->b_bcount), is_read);
 			} else {
 				error = ENXIO;
 				resid = bp->b_bcount;
+			}
 			bp->b_error = error;
 			bp->b_resid = resid;
 			biodone(bp);
 			mutex_enter(&sc->sc_slock);
 			continue;
+		}
 		/*
 		 * Clean the cache
 		 */
 		for (i = 0; i < sc->sc_cache_size; i++) {
 			crotor = (crotor + 1) % sc->sc_cache_size;
 			scp = sc->sc_cache + crotor;
 			if (scp->fc_type != FSS_CACHE_VALID)
 				continue;
 			mutex_exit(&sc->sc_slock);
 			thread_idle = false;
 			indirp = fss_bs_indir(sc, scp->fc_cluster);
 			if (indirp != NULL) {
 				error = fss_bs_io(sc, FSS_WRITE, sc->sc_clnext,
 , FSS_CLSIZE(sc), scp->fc_data, NULL);
 			} else
 				error = EIO;
 			mutex_enter(&sc->sc_slock);
 			if (error == 0) {
 				*indirp = sc->sc_clnext++;
 				sc->sc_indir_dirty = 1;
 			} else
 				fss_error(sc, "write error on backing store");
 			scp->fc_type = FSS_CACHE_FREE;
 			cv_broadcast(&sc->sc_cache_cv);
 			break;
+		}
 		/*
 		 * Process I/O requests
 		 */
 		if ((bp = bufq_get(sc->sc_bufq)) == NULL)
 			continue;
 		is_valid = (sc->sc_state == FSS_ACTIVE);
 		is_read = (bp->b_flags & B_READ);
 		thread_idle = false;
 		if (!is_valid) {
 			mutex_exit(&sc->sc_slock);
 			bp->b_error = ENXIO;
 			bp->b_resid = bp->b_bcount;
 			biodone(bp);
 			mutex_enter(&sc->sc_slock);
 			continue;
+		}
 		disk_busy(sc->sc_dkdev);
 		/*
 		 * First read from the snapshotted block device unless
 		 * this request is completely covered by backing store.
 		 */
 		cl = FSS_BTOCL(sc, dbtob(bp->b_blkno));
 		off = FSS_CLOFF(sc, dbtob(bp->b_blkno));