1 files changed, 477 insertions, 0 deletions

diff --git a/sys/kern/vfs_init.c b/sys/kern/vfs_init.c
new file mode 100644
index 0000000..b221cd3
--- /dev/null
+++ b/sys/kern/vfs_init.c
@@ -0,0 +1,477 @@
+/*
+ * Copyright (c) 1989, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed
+ * to Berkeley by John Heidemann of the UCLA Ficus project.
+ *
+ * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project
+ *
+ * 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.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
+ *
+ *	@(#)vfs_init.c	8.3 (Berkeley) 1/4/94
+ * $FreeBSD$
+ */
+
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/mount.h>
+#include <sys/sysctl.h>
+#include <sys/vnode.h>
+#include <sys/malloc.h>
+
+
+MALLOC_DEFINE(M_VNODE, "vnodes", "Dynamically allocated vnodes");
+
+/*
+ * The highest defined VFS number.
+ */
+int maxvfsconf = VFS_GENERIC + 1;
+
+/*
+ * Single-linked list of configured VFSes.
+ * New entries are added/deleted by vfs_register()/vfs_unregister()
+ */
+struct vfsconf *vfsconf;
+
+/*
+ * vfs_init.c
+ *
+ * Allocate and fill in operations vectors.
+ *
+ * An undocumented feature of this approach to defining operations is that
+ * there can be multiple entries in vfs_opv_descs for the same operations
+ * vector. This allows third parties to extend the set of operations
+ * supported by another layer in a binary compatibile way. For example,
+ * assume that NFS needed to be modified to support Ficus. NFS has an entry
+ * (probably nfs_vnopdeop_decls) declaring all the operations NFS supports by
+ * default. Ficus could add another entry (ficus_nfs_vnodeop_decl_entensions)
+ * listing those new operations Ficus adds to NFS, all without modifying the
+ * NFS code. (Of couse, the OTW NFS protocol still needs to be munged, but
+ * that is a(whole)nother story.) This is a feature.
+ */
+
+/* Table of known vnodeop vectors (list of VFS vnode vectors) */
+static const struct vnodeopv_desc **vnodeopv_descs;
+static int vnodeopv_num;
+
+/* Table of known descs (list of vnode op handlers "vop_access_desc") */
+static struct vnodeop_desc **vfs_op_descs;
+/* Reference counts for vfs_op_descs */
+static int *vfs_op_desc_refs;
+/* Number of descriptions */
+static int num_op_descs;
+/* Number of entries in each description */
+static int vfs_opv_numops = 64;
+
+/* Allow this number to be tuned at boot */
+TUNABLE_INT("vfs.opv_numops", &vfs_opv_numops);
+SYSCTL_INT(_vfs, OID_AUTO, opv_numops, CTLFLAG_RD, &vfs_opv_numops,
+	0, "Maximum number of operations in vop_t vector");
+
+static int int_cmp(const void *a, const void *b);
+
+static int
+int_cmp(const void *a, const void *b)
+{
+	return(*(const int *)a - *(const int *)b);
+}
+
+/*
+ * Recalculate the operations vector/description (those parts of it that can
+ * be recalculated, that is.)
+ * Always allocate operations vector large enough to hold vfs_opv_numops
+ * entries. The vector is never freed or deallocated once it is initialized,
+ * so that vnodes might safely reference it through their v_op pointer without
+ * vector changing suddenly from under them.
+ */
+static void
+vfs_opv_recalc(void)
+{
+	int i, j, k;
+	int *vfs_op_offsets;
+	vop_t ***opv_desc_vector_p;
+	vop_t **opv_desc_vector;
+	struct vnodeopv_entry_desc *opve_descp;
+	const struct vnodeopv_desc *opv;
+
+	if (vfs_op_descs == NULL)
+		panic("vfs_opv_recalc called with null vfs_op_descs");
+
+	/*
+	 * Allocate and initialize temporary array to store
+	 * offsets. Sort it to put all uninitialized entries
+	 * first and to make holes in existing offset sequence
+	 * detectable.
+	 */
+	MALLOC(vfs_op_offsets, int *,
+		num_op_descs * sizeof(int), M_TEMP, M_WAITOK);
+	if (vfs_op_offsets == NULL)
+		panic("vfs_opv_recalc: no memory");
+	for (i = 0; i < num_op_descs; i++)
+		vfs_op_offsets[i] = vfs_op_descs[i]->vdesc_offset;
+	qsort(vfs_op_offsets, num_op_descs, sizeof(int), int_cmp);
+
+	/*
+	 * Run through and make sure all known descs have an offset.
+	 * Use vfs_op_offsets to locate holes in offset sequence and
+	 * reuse them.
+	 * vop_default_desc is hardwired at offset 1, and offset 0
+	 * is a panic sanity check.
+	 */
+	j = 1; k = 1;
+	for (i = 0; i < num_op_descs; i++) {
+		if (vfs_op_descs[i]->vdesc_offset != 0)
+			continue;
+		/*
+		 * Look at two adjacent entries vfs_op_offsets[j - 1] and
+		 * vfs_op_offsets[j] and see if we can fit a new offset
+		 * number in between. If not, look at the next pair until
+		 * hole is found or the end of the vfs_op_offsets vector is
+		 * reached. j has been initialized to 1 above so that
+		 * referencing (j-1)-th element is safe and the loop will
+		 * never execute if num_op_descs is 1. For each new value s
+		 * of i the j loop pick up from where previous iteration has
+		 * left off. When the last hole has been consumed or if no
+		 * hole has been found, we will start allocating new numbers
+		 * starting from the biggest already available offset + 1.
+		 */
+		for (; j < num_op_descs; j++) {
+			if (vfs_op_offsets[j - 1] < k && vfs_op_offsets[j] > k)
+				break;
+			k = vfs_op_offsets[j] + 1;
+		}
+		vfs_op_descs[i]->vdesc_offset = k++;
+	}
+	FREE(vfs_op_offsets, M_TEMP);
+
+	/* Panic if new vops will cause vector overflow */
+	if (k > vfs_opv_numops)
+		panic("VFS: Ran out of vop_t vector entries. %d entries required, only %d available.\n", k, vfs_opv_numops);
+
+	/*
+	 * Allocate and fill in the vectors
+	 */
+	for (i = 0; i < vnodeopv_num; i++) {
+		opv = vnodeopv_descs[i];
+		opv_desc_vector_p = opv->opv_desc_vector_p;
+		if (*opv_desc_vector_p == NULL)
+			MALLOC(*opv_desc_vector_p, vop_t **,
+				vfs_opv_numops * sizeof(vop_t *), M_VNODE,
+				M_WAITOK | M_ZERO);
+
+		/* Fill in, with slot 0 being to return EOPNOTSUPP */
+		opv_desc_vector = *opv_desc_vector_p;
+		opv_desc_vector[0] = (vop_t *)vop_eopnotsupp;
+		for (j = 0; opv->opv_desc_ops[j].opve_op; j++) {
+			opve_descp = &(opv->opv_desc_ops[j]);
+			opv_desc_vector[opve_descp->opve_op->vdesc_offset] =
+				opve_descp->opve_impl;
+		}
+
+		/* Replace unfilled routines with their default (slot 1). */
+		opv_desc_vector = *(opv->opv_desc_vector_p);
+		if (opv_desc_vector[1] == NULL)
+			panic("vfs_opv_recalc: vector without a default.");
+		for (j = 0; j < vfs_opv_numops; j++)
+			if (opv_desc_vector[j] == NULL)
+				opv_desc_vector[j] = opv_desc_vector[1];
+	}
+}
+
+/* Add a set of vnode operations (a description) to the table above. */
+void
+vfs_add_vnodeops(const void *data)
+{
+	const struct vnodeopv_desc *opv;
+	const struct vnodeopv_desc **newopv;
+	struct vnodeop_desc **newop;
+	int *newref;
+	vop_t **opv_desc_vector;
+	struct vnodeop_desc *desc;
+	int i, j;
+
+	opv = (const struct vnodeopv_desc *)data;
+	MALLOC(newopv, const struct vnodeopv_desc **,
+	       (vnodeopv_num + 1) * sizeof(*newopv), M_VNODE, M_WAITOK);
+	if (vnodeopv_descs) {
+		bcopy(vnodeopv_descs, newopv, vnodeopv_num * sizeof(*newopv));
+		FREE(vnodeopv_descs, M_VNODE);
+	}
+	newopv[vnodeopv_num] = opv;
+	vnodeopv_descs = newopv;
+	vnodeopv_num++;
+
+	/* See if we have turned up a new vnode op desc */
+	opv_desc_vector = *(opv->opv_desc_vector_p);
+	for (i = 0; (desc = opv->opv_desc_ops[i].opve_op); i++) {
+		for (j = 0; j < num_op_descs; j++) {
+			if (desc == vfs_op_descs[j]) {
+				/* found it, increase reference count */
+				vfs_op_desc_refs[j]++;
+				break;
+			}
+		}
+		if (j == num_op_descs) {
+			/* not found, new entry */
+			MALLOC(newop, struct vnodeop_desc **,
+			       (num_op_descs + 1) * sizeof(*newop),
+			       M_VNODE, M_WAITOK);
+			/* new reference count (for unload) */
+			MALLOC(newref, int *,
+				(num_op_descs + 1) * sizeof(*newref),
+				M_VNODE, M_WAITOK);
+			if (vfs_op_descs) {
+				bcopy(vfs_op_descs, newop,
+					num_op_descs * sizeof(*newop));
+				FREE(vfs_op_descs, M_VNODE);
+			}
+			if (vfs_op_desc_refs) {
+				bcopy(vfs_op_desc_refs, newref,
+					num_op_descs * sizeof(*newref));
+				FREE(vfs_op_desc_refs, M_VNODE);
+			}
+			newop[num_op_descs] = desc;
+			newref[num_op_descs] = 1;
+			vfs_op_descs = newop;
+			vfs_op_desc_refs = newref;
+			num_op_descs++;
+		}
+	}
+	vfs_opv_recalc();
+}
+
+/* Remove a vnode type from the vnode description table above. */
+void
+vfs_rm_vnodeops(const void *data)
+{
+	const struct vnodeopv_desc *opv;
+	const struct vnodeopv_desc **newopv;
+	struct vnodeop_desc **newop;
+	int *newref;
+	vop_t **opv_desc_vector;
+	struct vnodeop_desc *desc;
+	int i, j, k;
+
+	opv = (const struct vnodeopv_desc *)data;
+	/* Lower ref counts on descs in the table and release if zero */
+	for (i = 0; (desc = opv->opv_desc_ops[i].opve_op); i++) {
+		for (j = 0; j < num_op_descs; j++) {
+			if (desc == vfs_op_descs[j]) {
+				/* found it, decrease reference count */
+				vfs_op_desc_refs[j]--;
+				break;
+			}
+		}
+		for (j = 0; j < num_op_descs; j++) {
+			if (vfs_op_desc_refs[j] > 0)
+				continue;
+			if (vfs_op_desc_refs[j] < 0)
+				panic("vfs_remove_vnodeops: negative refcnt");
+			/* Entry is going away - replace it with defaultop */
+			for (k = 0; k < vnodeopv_num; k++) {
+				opv_desc_vector = 
+					*(vnodeopv_descs[k]->opv_desc_vector_p);
+				if (opv_desc_vector != NULL)
+					opv_desc_vector[desc->vdesc_offset] =
+						opv_desc_vector[1];
+			}
+			MALLOC(newop, struct vnodeop_desc **,
+			       (num_op_descs - 1) * sizeof(*newop),
+			       M_VNODE, M_WAITOK);
+			/* new reference count (for unload) */
+			MALLOC(newref, int *,
+				(num_op_descs - 1) * sizeof(*newref),
+				M_VNODE, M_WAITOK);
+			for (k = j; k < (num_op_descs - 1); k++) {
+				vfs_op_descs[k] = vfs_op_descs[k + 1];
+				vfs_op_desc_refs[k] = vfs_op_desc_refs[k + 1];
+			}
+			bcopy(vfs_op_descs, newop,
+				(num_op_descs - 1) * sizeof(*newop));
+			bcopy(vfs_op_desc_refs, newref,
+				(num_op_descs - 1) * sizeof(*newref));
+			FREE(vfs_op_descs, M_VNODE);
+			FREE(vfs_op_desc_refs, M_VNODE);
+			vfs_op_descs = newop;
+			vfs_op_desc_refs = newref;
+			num_op_descs--;
+		}
+	}
+
+	for (i = 0; i < vnodeopv_num; i++) {
+		if (vnodeopv_descs[i] == opv) {
+			for (j = i; j < (vnodeopv_num - 1); j++)
+				vnodeopv_descs[j] = vnodeopv_descs[j + 1];
+			break;
+		}
+	}
+	if (i == vnodeopv_num)
+		panic("vfs_remove_vnodeops: opv not found");
+	opv_desc_vector = *(opv->opv_desc_vector_p);
+	if (opv_desc_vector != NULL)
+		FREE(opv_desc_vector, M_VNODE);
+	MALLOC(newopv, const struct vnodeopv_desc **,
+	       (vnodeopv_num - 1) * sizeof(*newopv), M_VNODE, M_WAITOK);
+	bcopy(vnodeopv_descs, newopv, (vnodeopv_num - 1) * sizeof(*newopv));
+	FREE(vnodeopv_descs, M_VNODE);
+	vnodeopv_descs = newopv;
+	vnodeopv_num--;
+
+	vfs_opv_recalc();
+}
+
+/*
+ * Routines having to do with the management of the vnode table.
+ */
+struct vattr va_null;
+
+/*
+ * Initialize the vnode structures and initialize each filesystem type.
+ */
+/* ARGSUSED*/
+static void
+vfsinit(void *dummy)
+{
+
+	vattr_null(&va_null);
+}
+SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_FIRST, vfsinit, NULL)
+
+/* Register a new filesystem type in the global table */
+int
+vfs_register(struct vfsconf *vfc)
+{
+	struct sysctl_oid *oidp;
+	struct vfsconf *vfsp;
+
+	vfsp = NULL;
+	if (vfsconf)
+		for (vfsp = vfsconf; vfsp->vfc_next; vfsp = vfsp->vfc_next)
+			if (strcmp(vfc->vfc_name, vfsp->vfc_name) == 0)
+				return EEXIST;
+
+	vfc->vfc_typenum = maxvfsconf++;
+	if (vfsp)
+		vfsp->vfc_next = vfc;
+	else
+		vfsconf = vfc;
+	vfc->vfc_next = NULL;
+
+	/*
+	 * If this filesystem has a sysctl node under vfs
+	 * (i.e. vfs.xxfs), then change the oid number of that node to 
+	 * match the filesystem's type number.  This allows user code
+	 * which uses the type number to read sysctl variables defined
+	 * by the filesystem to continue working. Since the oids are
+	 * in a sorted list, we need to make sure the order is
+	 * preserved by re-registering the oid after modifying its
+	 * number.
+	 */
+	SLIST_FOREACH(oidp, &sysctl__vfs_children, oid_link)
+		if (strcmp(oidp->oid_name, vfc->vfc_name) == 0) {
+			sysctl_unregister_oid(oidp);
+			oidp->oid_number = vfc->vfc_typenum;
+			sysctl_register_oid(oidp);
+		}
+
+	/*
+	 * Call init function for this VFS...
+	 */
+	(*(vfc->vfc_vfsops->vfs_init))(vfc);
+
+	return 0;
+}
+
+
+/* Remove registration of a filesystem type */
+int
+vfs_unregister(struct vfsconf *vfc)
+{
+	struct vfsconf *vfsp, *prev_vfsp;
+	int error, i, maxtypenum;
+
+	i = vfc->vfc_typenum;
+
+	prev_vfsp = NULL;
+	for (vfsp = vfsconf; vfsp;
+			prev_vfsp = vfsp, vfsp = vfsp->vfc_next) {
+		if (!strcmp(vfc->vfc_name, vfsp->vfc_name))
+			break;
+	}
+	if (vfsp == NULL)
+		return EINVAL;
+	if (vfsp->vfc_refcount)
+		return EBUSY;
+	if (vfc->vfc_vfsops->vfs_uninit != NULL) {
+		error = (*vfc->vfc_vfsops->vfs_uninit)(vfsp);
+		if (error)
+			return (error);
+	}
+	if (prev_vfsp)
+		prev_vfsp->vfc_next = vfsp->vfc_next;
+	else
+		vfsconf = vfsp->vfc_next;
+	maxtypenum = VFS_GENERIC;
+	for (vfsp = vfsconf; vfsp != NULL; vfsp = vfsp->vfc_next)
+		if (maxtypenum < vfsp->vfc_typenum)
+			maxtypenum = vfsp->vfc_typenum;
+	maxvfsconf = maxtypenum + 1;
+	return 0;
+}
+
+/*
+ * Standard kernel module handling code for filesystem modules.
+ * Referenced from VFS_SET().
+ */
+int
+vfs_modevent(module_t mod, int type, void *data)
+{
+	struct vfsconf *vfc;
+	int error = 0;
+
+	vfc = (struct vfsconf *)data;
+
+	switch (type) {
+	case MOD_LOAD:
+		if (vfc)
+			error = vfs_register(vfc);
+		break;
+
+	case MOD_UNLOAD:
+		if (vfc)
+			error = vfs_unregister(vfc);
+		break;
+	default:	/* including MOD_SHUTDOWN */
+		break;
+	}
+	return (error);
+}