Add GEOM class "VFS" for filesystems and other buffer cache users

of GEOM devices.

There is nothing magic about this, it just gives a bufobj interface
to GEOM.

2 files changed, 194 insertions, 0 deletions

diff --git a/sys/geom/geom_vfs.c b/sys/geom/geom_vfs.c
new file mode 100644
index 0000000..2a1885c
--- /dev/null
+++ b/sys/geom/geom_vfs.c
@@ -0,0 +1,152 @@
+/*-
+ * Copyright (c) 2004 Poul-Henning Kamp
+ * All rights reserved.
+ *
+ * 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 AUTHOR 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 AUTHOR 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.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/bio.h>
+#include <sys/kernel.h>
+#include <sys/malloc.h>
+#include <sys/vnode.h>
+
+#include <geom/geom.h>
+#include <geom/geom_vfs.h>
+
+/*
+ * subroutines for use by filesystems.
+ *
+ * XXX: should maybe live somewhere else ?
+ */
+#include <sys/buf.h>
+
+static struct buf_ops __g_vfs_bufops = {
+	.bop_name =	"GEOM_VFS",
+	.bop_write =	bufwrite,
+	.bop_strategy =	g_vfs_strategy,	
+};
+
+struct buf_ops *g_vfs_bufops = &__g_vfs_bufops;
+
+static struct g_class g_vfs_class = {
+	.name =		"VFS",
+	.version =	G_VERSION,
+	.orphan =	g_vfs_orphan,
+};
+
+DECLARE_GEOM_CLASS(g_vfs_class, g_vfs);
+
+static void
+g_vfs_done(struct bio *bip)
+{
+	struct buf *bp;
+
+	if (bip->bio_error) {
+		printf("ffs_geom_done():");
+		g_print_bio(bip);
+		printf("error = %d\n", bip->bio_error);
+	}
+	bp = bip->bio_caller2;
+	bp->b_error = bip->bio_error;
+	bp->b_ioflags = bip->bio_flags;
+	if (bip->bio_error)
+		bp->b_ioflags |= BIO_ERROR;
+	bp->b_resid = bp->b_bcount - bip->bio_completed;
+	g_destroy_bio(bip);
+	mtx_lock(&Giant);
+	bufdone(bp);
+	mtx_unlock(&Giant);
+}
+
+void
+g_vfs_strategy(struct bufobj *bo, struct buf *bp)
+{
+	struct g_consumer *cp;
+	struct bio *bip;
+
+	cp = bo->bo_private;
+	G_VALID_CONSUMER(cp);
+
+	bip = g_alloc_bio();
+	bip->bio_cmd = bp->b_iocmd;
+	bip->bio_offset = bp->b_iooffset;
+	bip->bio_data = bp->b_data;
+	bip->bio_done = g_vfs_done;
+	bip->bio_caller2 = bp;
+	bip->bio_length = bp->b_bcount;
+	g_io_request(bip, cp);
+}
+
+void
+g_vfs_orphan(struct g_consumer *cp)
+{
+
+	/*
+	 * Don't do anything here yet.
+	 *
+	 * Ideally we should detach the consumer already now, but that
+	 * leads to a locking requirement in the I/O path to see if we have
+	 * a consumer or not.  Considering how ugly things are going to get
+	 * anyway as none of our filesystems are graceful about i/o errors,
+	 * this is not important right now.
+	 *
+	 * Down the road, this is the place where we could give the user
+	 * a "Abort, Retry or Ignore" option to replace the media again.
+	 */
+}
+
+int
+g_vfs_open(struct vnode *vp, struct g_consumer **cpp, const char *fsname, int wr)
+{
+	struct g_geom *gp;
+	struct g_provider *pp;
+	struct g_consumer *cp;
+	struct bufobj *bo;
+	int error;
+
+	g_topology_assert();
+
+	*cpp = NULL;
+	pp = g_dev_getprovider(vp->v_rdev);
+	if (pp == NULL)
+		return (ENOENT);
+	gp = g_new_geomf(&g_vfs_class, "%s.%s", fsname, pp->name);
+	cp = g_new_consumer(gp);
+	g_attach(cp, pp);
+	error = g_access(cp, 1, wr, 1);
+	if (error) {
+		g_wither_geom(gp, ENXIO);
+		return (error);
+	}
+	*cpp = cp;
+	bo = &vp->v_bufobj;
+	bo->bo_ops = g_vfs_bufops;
+	bo->bo_private = cp;
+	bo->bo_bsize = pp->sectorsize;
+
+	return (error);
+}
diff --git a/sys/geom/geom_vfs.h b/sys/geom/geom_vfs.h
new file mode 100644
index 0000000..6c2bacb
--- /dev/null
+++ b/sys/geom/geom_vfs.h
@@ -0,0 +1,42 @@
+/*-
+ * Copyright (c) 2004 Poul-Henning Kamp
+ * All rights reserved.
+ *
+ * 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 AUTHOR 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 AUTHOR 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.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _GEOM_GEOM_VFS_H_
+#define _GEOM_GEOM_VFS_H_
+
+struct vnode;
+struct bufobj;
+struct buf;
+
+extern struct buf_ops *g_vfs_bufops;
+
+void g_vfs_strategy(struct bufobj *bo, struct buf *bp);
+void g_vfs_orphan(struct g_consumer *cp);
+int g_vfs_open(struct vnode *vp, struct g_consumer **cpp, const char *fsname, int wr);
+
+#endif /* _GEOM_GEOM_VFS_H_ */