1 files changed, 285 insertions, 0 deletions
diff --git a/sys/fs/pseudofs/pseudofs_fileno.c b/sys/fs/pseudofs/pseudofs_fileno.c
new file mode 100644
index 0000000..877b7b8
--- /dev/null
+++ b/sys/fs/pseudofs/pseudofs_fileno.c
@@ -0,0 +1,285 @@
+/*-
+ * Copyright (c) 2001 Dag-Erling Coïdan Smørgrav
+ * 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
+ *    in this position and unchanged.
+ * 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. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
+ *
+ *      $FreeBSD$
+ */
+
+#include <sys/param.h>
+#include <sys/kernel.h>
+#include <sys/systm.h>
+#include <sys/malloc.h>
+#include <sys/mount.h>
+#include <sys/proc.h>
+#include <sys/sbuf.h>
+#include <sys/sysctl.h>
+
+#include <machine/limits.h>
+
+#include <fs/pseudofs/pseudofs.h>
+#include <fs/pseudofs/pseudofs_internal.h>
+
+static MALLOC_DEFINE(M_PFSFILENO, "pseudofs_fileno", "pseudofs fileno bitmap");
+
+static struct mtx pfs_fileno_mutex;
+
+#define PFS_BITMAP_SIZE	4096
+#define PFS_SLOT_BITS	(sizeof(unsigned int) * CHAR_BIT)
+#define PFS_BITMAP_BITS	(PFS_BITMAP_SIZE * PFS_SLOT_BITS)
+struct pfs_bitmap {
+	u_int32_t		 pb_offset;
+	int			 pb_used;
+	unsigned int		 pb_bitmap[PFS_BITMAP_SIZE];
+	struct pfs_bitmap	*pb_next;
+};
+
+/*
+ * Initialization
+ */
+void
+pfs_fileno_load(void)
+{
+	mtx_init(&pfs_fileno_mutex, "pseudofs_fileno", MTX_DEF);
+}
+
+/*
+ * Teardown
+ */
+void
+pfs_fileno_unload(void)
+{
+	mtx_destroy(&pfs_fileno_mutex);
+}
+
+/*
+ * Initialize fileno bitmap
+ */
+void
+pfs_fileno_init(struct pfs_info *pi)
+{
+	struct pfs_bitmap *pb;
+	
+	MALLOC(pb, struct pfs_bitmap *, sizeof *pb,
+	    M_PFSFILENO, M_WAITOK|M_ZERO);
+
+	mtx_lock(&pi->pi_mutex);
+	
+	pb->pb_bitmap[0] = 07;
+	pb->pb_used = 3;
+	pi->pi_bitmap = pb;
+	pi->pi_root->pn_fileno = 2;
+
+	mtx_unlock(&pi->pi_mutex);
+}
+
+/*
+ * Tear down fileno bitmap
+ */
+void
+pfs_fileno_uninit(struct pfs_info *pi)
+{
+	struct pfs_bitmap *pb, *npb;
+	int used;
+	
+	mtx_lock(&pi->pi_mutex);
+	
+	pb = pi->pi_bitmap;
+	pi->pi_bitmap = NULL;
+	
+	mtx_unlock(&pi->pi_mutex);
+
+	for (used = 0; pb; pb = npb) {
+		npb = pb->pb_next;
+		used += pb->pb_used;
+		FREE(pb, M_PFSFILENO);
+	}
+	if (used > 2)
+		printf("WARNING: %d file numbers still in use\n", used);
+}
+
+/*
+ * Get the next available file number
+ */
+static u_int32_t
+pfs_get_fileno(struct pfs_info *pi)
+{
+	struct pfs_bitmap *pb, *ppb;
+	u_int32_t fileno;
+	unsigned int *p;
+	int i;
+
+	mtx_lock(&pi->pi_mutex);
+	
+	/* look for the first page with free bits */
+	for (ppb = NULL, pb = pi->pi_bitmap; pb; ppb = pb, pb = pb->pb_next)
+		if (pb->pb_used != PFS_BITMAP_BITS)
+			break;
+
+	/* out of pages? */
+	if (pb == NULL) {
+		mtx_unlock(&pi->pi_mutex);
+		MALLOC(pb, struct pfs_bitmap *, sizeof *pb,
+		    M_PFSFILENO, M_WAITOK|M_ZERO);
+		mtx_lock(&pi->pi_mutex);
+		/* protect against possible race */
+		while (ppb->pb_next)
+			ppb = ppb->pb_next;
+		pb->pb_offset = ppb->pb_offset + PFS_BITMAP_BITS;
+		ppb->pb_next = pb;
+	}
+
+	/* find the first free slot */
+	for (i = 0; i < PFS_BITMAP_SIZE; ++i)
+		if (pb->pb_bitmap[i] != UINT_MAX)
+			break;
+	
+	/* find the first available bit and flip it */
+	fileno = pb->pb_offset + i * PFS_SLOT_BITS;
+	p = &pb->pb_bitmap[i];
+	for (i = 0; i < PFS_SLOT_BITS; ++i, ++fileno)
+		if ((*p & (unsigned int)(1 << i)) == 0)
+			break;
+	KASSERT(i < PFS_SLOT_BITS,
+	    ("slot has free bits, yet doesn't"));
+	*p |= (unsigned int)(1 << i);
+	++pb->pb_used;
+	
+	mtx_unlock(&pi->pi_mutex);
+	
+	return fileno;
+}
+
+/*
+ * Free a file number
+ */
+static void
+pfs_free_fileno(struct pfs_info *pi, u_int32_t fileno)
+{
+	struct pfs_bitmap *pb;
+	unsigned int *p;
+	int i;
+
+	mtx_lock(&pi->pi_mutex);
+	
+	/* find the right page */
+	for (pb = pi->pi_bitmap;
+	     pb && fileno >= PFS_BITMAP_BITS;
+	     pb = pb->pb_next, fileno -= PFS_BITMAP_BITS)
+		/* nothing */ ;
+	KASSERT(pb,
+	    ("fileno isn't in any bitmap"));
+
+	/* find the right bit in the right slot and flip it */
+	p = &pb->pb_bitmap[fileno / PFS_SLOT_BITS];
+	i = fileno % PFS_SLOT_BITS;
+	KASSERT(*p & (unsigned int)(1 << i),
+	    ("fileno is already free"));
+	*p &= ~((unsigned int)(1 << i));
+	--pb->pb_used;
+
+	mtx_unlock(&pi->pi_mutex);
+}
+
+/*
+ * Allocate a file number
+ */
+void
+pfs_fileno_alloc(struct pfs_info *pi, struct pfs_node *pn)
+{
+	/* make sure our parent has a file number */
+	if (pn->pn_parent && !pn->pn_parent->pn_fileno)
+		pfs_fileno_alloc(pi, pn->pn_parent);
+	
+	switch (pn->pn_type) {
+	case pfstype_root:
+	case pfstype_dir:
+	case pfstype_file:
+	case pfstype_symlink:
+		pn->pn_fileno = pfs_get_fileno(pi);
+		break;
+	case pfstype_this:
+		KASSERT(pn->pn_parent != NULL,
+		    ("pfstype_this node has no parent"));
+		pn->pn_fileno = pn->pn_parent->pn_fileno;
+		break;
+	case pfstype_parent:
+		KASSERT(pn->pn_parent != NULL,
+		    ("pfstype_parent node has no parent"));
+		if (pn->pn_parent == pi->pi_root) {
+			pn->pn_fileno = pn->pn_parent->pn_fileno;
+			break;
+		}
+		KASSERT(pn->pn_parent->pn_parent != NULL,
+		    ("pfstype_parent node has no grandparent"));
+		pn->pn_fileno = pn->pn_parent->pn_parent->pn_fileno;
+		break;
+	case pfstype_procdep:
+		KASSERT(1,
+		    ("pfs_fileno_alloc() called for pfstype_procdep node"));
+		break;
+	case pfstype_none:
+		KASSERT(1,
+		    ("pfs_fileno_alloc() called for pfstype_none node"));
+		break;
+ 	}
+	
+	printf("pfs_fileno_alloc(): %s: ", pi->pi_name);
+	if (pn->pn_parent) {
+		if (pn->pn_parent->pn_parent) {
+			printf("%s/", pn->pn_parent->pn_parent->pn_name);
+		}
+		printf("%s/", pn->pn_parent->pn_name);
+	}
+	printf("%s -> %d\n", pn->pn_name, pn->pn_fileno);
+}
+
+/*
+ * Release a file number
+ */
+void
+pfs_fileno_free(struct pfs_info *pi, struct pfs_node *pn)
+{
+	switch (pn->pn_type) {
+	case pfstype_root:
+	case pfstype_dir:
+	case pfstype_file:
+	case pfstype_symlink:
+		pfs_free_fileno(pi, pn->pn_fileno);
+		break;
+	case pfstype_this:
+	case pfstype_parent:
+		/* ignore these, as they don't "own" their file number */
+		break;
+	case pfstype_procdep:
+		KASSERT(1,
+		    ("pfs_fileno_free() called for pfstype_procdep node"));
+		break;
+	case pfstype_none:
+		KASSERT(1,
+		    ("pfs_fileno_free() called for pfstype_none node"));
+		break;
+	}
+}