MFp4: Add tmpfs, an efficient memory file system.

Please note that, this is currently considered as an
experimental feature so there could be some rough
edges.  Consult http://wiki.freebsd.org/TMPFS for
more information.

For now, connect tmpfs to build on i386 and amd64
architectures only.  Please let us know if you have
success with other platforms.

This work was developed by Julio M. Merino Vidal
for NetBSD as a SoC project; Rohit Jalan ported it
from NetBSD to FreeBSD.  Howard Su and Glen Leeder
are worked on it to continue this effort.

Obtained from:	NetBSD via p4
Submitted by:	Howard Su (with some minor changes)
Approved by:	re (kensmith)

1 files changed, 418 insertions, 0 deletions

diff --git a/sys/fs/tmpfs/tmpfs_vfsops.c b/sys/fs/tmpfs/tmpfs_vfsops.c
new file mode 100644
index 0000000..e5d3d6e
--- /dev/null
+++ b/sys/fs/tmpfs/tmpfs_vfsops.c
@@ -0,0 +1,418 @@
+/*	$NetBSD: tmpfs_vfsops.c,v 1.10 2005/12/11 12:24:29 christos Exp $	*/
+
+/*
+ * Copyright (c) 2005 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Julio M. Merino Vidal, developed as part of Google's Summer of Code
+ * 2005 program.
+ *
+ * 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 NetBSD
+ *        Foundation, Inc. and its contributors.
+ * 4. Neither the name of The NetBSD Foundation 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 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.
+ */
+
+/*
+ * Efficient memory file system.
+ *
+ * tmpfs is a file system that uses NetBSD's virtual memory sub-system
+ * (the well-known UVM) to store file data and metadata in an efficient
+ * way.  This means that it does not follow the structure of an on-disk
+ * file system because it simply does not need to.  Instead, it uses
+ * memory-specific data structures and algorithms to automatically
+ * allocate and release resources.
+ */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#include <sys/kernel.h>
+#include <sys/stat.h>
+#include <sys/systm.h>
+#include <sys/sysctl.h>
+
+#include <vm/vm.h>
+#include <vm/vm_object.h>
+#include <vm/vm_param.h>
+
+#include <fs/tmpfs/tmpfs.h>
+
+/*
+ * Default permission for root node 
+ */
+#define TMPFS_DEFAULT_ROOT_MODE	(S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)
+
+MALLOC_DEFINE(M_TMPFSMNT, "tmpfs mount", "tmpfs mount structures");
+
+/* --------------------------------------------------------------------- */
+
+static int	tmpfs_mount(struct mount *, struct thread *);
+static int	tmpfs_unmount(struct mount *, int, struct thread *);
+static int	tmpfs_root(struct mount *, int flags, struct vnode **,
+		    struct thread *);
+static int	tmpfs_fhtovp(struct mount *, struct fid *, struct vnode **);
+static int	tmpfs_statfs(struct mount *, struct statfs *, struct thread *);
+
+/* --------------------------------------------------------------------- */
+
+static const char *tmpfs_opts[] = {
+	"from", "size", "inodes", "uid", "gid", "mode", 
+	NULL
+};
+
+/* --------------------------------------------------------------------- */
+
+#define SWI_MAXMIB	3
+
+static int
+get_swpgtotal(void)
+{
+	struct xswdev xsd;
+	char *sname = "vm.swap_info";
+	int soid[SWI_MAXMIB], oid[2];
+	int unswdev, total, dmmax, nswapdev;
+	size_t mibi, len;
+
+	total = 0;
+
+	len = sizeof(dmmax);
+	if (kernel_sysctlbyname(curthread, "vm.dmmax", &dmmax, &len,
+				NULL, 0, NULL, 0) != 0)
+		return total;
+
+	len = sizeof(nswapdev);
+	if (kernel_sysctlbyname(curthread, "vm.nswapdev", 
+				&nswapdev, &len,
+				NULL, 0, NULL, 0) != 0)
+		return total;
+
+	mibi = (SWI_MAXMIB - 1) * sizeof(int);
+	oid[0] = 0;
+	oid[1] = 3;
+
+	if (kernel_sysctl(curthread, oid, 2, 
+			soid, &mibi, (void *)sname, strlen(sname),
+			NULL, 0) != 0)
+		return total;
+
+	mibi = (SWI_MAXMIB - 1);
+	for (unswdev = 0; unswdev < nswapdev; ++unswdev) {
+		soid[mibi] = unswdev;
+		len = sizeof(struct xswdev);
+		if (kernel_sysctl(curthread, 
+				soid, mibi + 1, &xsd, &len, NULL, 0, 
+				NULL, 0) != 0)
+			return total;
+		if (len == sizeof(struct xswdev))
+			total += (xsd.xsw_nblks - dmmax);
+	}
+
+	/* Not Reached */
+	return total;
+}
+
+/* --------------------------------------------------------------------- */
+
+static int
+tmpfs_mount(struct mount *mp, struct thread *l)
+{
+	struct tmpfs_args args;
+	struct tmpfs_mount *tmp;
+	struct tmpfs_node *root;
+	size_t pages, mem_size;
+	ino_t nodes;
+	int error;
+
+	if (vfs_filteropt(mp->mnt_optnew, tmpfs_opts))
+		return (EINVAL);
+
+	if (mp->mnt_flag & MNT_UPDATE) {
+		/* XXX: There is no support yet to update file system
+		 * settings.  Should be added. */
+
+		return EOPNOTSUPP;
+	}
+
+	if (vfs_scanopt(mp->mnt_optnew, "gid", "%d", &args.ta_root_gid) != 1)
+		args.ta_root_gid = 0;
+	if (vfs_scanopt(mp->mnt_optnew, "uid", "%d", &args.ta_root_uid) != 1)
+		args.ta_root_uid = 0;
+	if (vfs_scanopt(mp->mnt_optnew, "mode", "%o", &args.ta_root_mode) != 1)
+		args.ta_root_mode = TMPFS_DEFAULT_ROOT_MODE;
+	if(vfs_scanopt(mp->mnt_optnew, "inodes", "%d", &args.ta_nodes_max) != 1)
+		args.ta_nodes_max = 0;
+
+	if(vfs_scanopt(mp->mnt_optnew, 
+			"size", 
+			"%qu", &args.ta_size_max) != 1)
+		args.ta_size_max = 0;
+
+	/* Do not allow mounts if we do not have enough memory to preserve
+	 * the minimum reserved pages. */
+	mem_size = cnt.v_free_count + cnt.v_inactive_count + get_swpgtotal();
+	mem_size -= mem_size > cnt.v_wire_count ? cnt.v_wire_count : mem_size;
+	if (mem_size < TMPFS_PAGES_RESERVED)
+		return ENOSPC;
+
+	/* Get the maximum number of memory pages this file system is
+	 * allowed to use, based on the maximum size the user passed in
+	 * the mount structure.  A value of zero is treated as if the
+	 * maximum available space was requested. */
+	if (args.ta_size_max < PAGE_SIZE || args.ta_size_max >= SIZE_MAX)
+		pages = SIZE_MAX;
+	else
+		pages = args.ta_size_max / PAGE_SIZE +
+		    (args.ta_size_max % PAGE_SIZE == 0 ? 0 : 1);
+	MPASS(pages > 0);
+
+	if (args.ta_nodes_max <= 3)
+		nodes = 3 + pages * PAGE_SIZE / 1024;
+	else
+		nodes = args.ta_nodes_max;
+	MPASS(nodes >= 3);
+
+	/* Allocate the tmpfs mount structure and fill it. */
+	tmp = (struct tmpfs_mount *)malloc(sizeof(struct tmpfs_mount),
+	    M_TMPFSMNT, M_WAITOK | M_ZERO);
+	
+	mtx_init(&tmp->allnode_lock, "tmpfs allnode lock", NULL, MTX_DEF);
+	tmp->tm_nodes_max = nodes;
+	tmp->tm_nodes_last = 2;
+	tmp->tm_nodes_inuse = 0;
+	tmp->tm_maxfilesize = get_swpgtotal() * PAGE_SIZE;
+	LIST_INIT(&tmp->tm_nodes_used);
+	LIST_INIT(&tmp->tm_nodes_avail);
+
+	tmp->tm_pages_max = pages;
+	tmp->tm_pages_used = 0;
+	tmp->tm_dirent_pool = tmpfs_zone_create(
+					"TMPFS dirent",
+					sizeof(struct tmpfs_dirent),
+					UMA_ALIGN_PTR,
+	    				tmp);
+	tmp->tm_node_pool = tmpfs_zone_create(
+					"TMPFS node",
+					sizeof(struct tmpfs_node),
+					UMA_ALIGN_PTR,
+					tmp);
+	tmpfs_str_zone_create(&tmp->tm_str_pool, tmp);
+
+	/* Allocate the root node. */
+	error = tmpfs_alloc_node(tmp, VDIR, args.ta_root_uid,
+	    args.ta_root_gid, args.ta_root_mode & ALLPERMS, NULL, NULL,
+	    VNOVAL, l, &root);
+
+	if (error != 0 || root == NULL) {
+	    tmpfs_str_zone_destroy(&tmp->tm_str_pool);
+	    tmpfs_zone_destroy(tmp->tm_node_pool);
+	    tmpfs_zone_destroy(tmp->tm_dirent_pool);
+	    free(tmp, M_TMPFSMNT);
+	    return error;
+	}
+	tmp->tm_root = root;
+
+	MNT_ILOCK(mp);
+	mp->mnt_flag |= MNT_LOCAL;
+	mp->mnt_kern_flag |= MNTK_MPSAFE;
+	MNT_IUNLOCK(mp);
+	
+	mp->mnt_data = tmp;
+	mp->mnt_stat.f_namemax = MAXNAMLEN;
+	vfs_getnewfsid(mp);
+	vfs_mountedfrom(mp, "tmpfs");
+
+	return 0;
+}
+
+/* --------------------------------------------------------------------- */
+
+/* ARGSUSED2 */
+static int
+tmpfs_unmount(struct mount *mp, int mntflags, struct thread *l)
+{
+	int error;
+	int flags = 0;
+	struct tmpfs_mount *tmp;
+	struct tmpfs_node *node;
+
+	/* Handle forced unmounts. */
+	if (mntflags & MNT_FORCE)
+		flags |= FORCECLOSE;
+
+	/* Finalize all pending I/O. */
+	error = vflush(mp, 0, flags, l);
+	if (error != 0)
+		return error;
+
+	tmp = VFS_TO_TMPFS(mp);
+	
+	/* Free all associated data.  The loop iterates over the linked list
+	 * we have containing all used nodes.  For each of them that is
+	 * a directory, we free all its directory entries.  Note that after
+	 * freeing a node, it will automatically go to the available list,
+	 * so we will later have to iterate over it to release its items. */
+	node = LIST_FIRST(&tmp->tm_nodes_used);
+	while (node != NULL) {
+		struct tmpfs_node *next;
+
+		if (node->tn_type == VDIR) {
+			struct tmpfs_dirent *de;
+
+			de = TAILQ_FIRST(&node->tn_dir.tn_dirhead);
+			while (de != NULL) {
+				struct tmpfs_dirent *nde;
+
+				nde = TAILQ_NEXT(de, td_entries);
+				tmpfs_free_dirent(tmp, de, FALSE);
+				de = nde;
+				node->tn_size -= sizeof(struct tmpfs_dirent);
+			}
+		}
+
+		next = LIST_NEXT(node, tn_entries);
+		tmpfs_free_node(tmp, node);
+		node = next;
+	}
+	node = LIST_FIRST(&tmp->tm_nodes_avail);
+	while (node != NULL) {
+		struct tmpfs_node *next;
+
+		next = LIST_NEXT(node, tn_entries);
+		LIST_REMOVE(node, tn_entries);
+		tmpfs_zone_free(tmp->tm_node_pool, node);
+		node = next;
+	}
+
+	tmpfs_zone_destroy(tmp->tm_dirent_pool);
+	tmpfs_zone_destroy(tmp->tm_node_pool);
+	tmpfs_str_zone_destroy(&tmp->tm_str_pool);
+
+	mtx_destroy(&tmp->allnode_lock);
+	MPASS(tmp->tm_pages_used == 0);
+
+	/* Throw away the tmpfs_mount structure. */
+	free(mp->mnt_data, M_TMPFSMNT);
+	mp->mnt_data = NULL;
+	
+	MNT_ILOCK(mp);
+	mp->mnt_flag &= ~MNT_LOCAL;
+	MNT_IUNLOCK(mp);
+	return 0;
+}
+
+/* --------------------------------------------------------------------- */
+
+static int
+tmpfs_root(struct mount *mp, int flags, struct vnode **vpp, struct thread *td)
+{
+	int error;
+	error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, vpp, td);
+
+	if (!error)
+		(*vpp)->v_vflag = VV_ROOT;
+
+	return error;
+}
+
+/* --------------------------------------------------------------------- */
+
+static int
+tmpfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
+{
+	boolean_t found;
+	struct tmpfs_fid *tfhp;
+	struct tmpfs_mount *tmp;
+	struct tmpfs_node *node;
+
+	tmp = VFS_TO_TMPFS(mp);
+
+	tfhp = (struct tmpfs_fid *)fhp;
+	if (tfhp->tf_len != sizeof(struct tmpfs_fid))
+		return EINVAL;
+
+	if (tfhp->tf_id >= tmp->tm_nodes_max)
+		return EINVAL;
+
+	found = FALSE;
+
+	TMPFS_LOCK(tmp);
+	LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) {
+		if (node->tn_id == tfhp->tf_id &&
+		    node->tn_gen == tfhp->tf_gen) {
+			found = TRUE;
+			break;
+		}
+	}
+	TMPFS_UNLOCK(tmp);
+
+	return found ? tmpfs_alloc_vp(mp, node, vpp, curthread) : EINVAL;
+}
+
+/* --------------------------------------------------------------------- */
+
+/* ARGSUSED2 */
+static int
+tmpfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *l)
+{
+	fsfilcnt_t freenodes;
+	struct tmpfs_mount *tmp;
+
+	tmp = VFS_TO_TMPFS(mp);
+
+	sbp->f_iosize = PAGE_SIZE; 
+	sbp->f_bsize = PAGE_SIZE;
+
+	sbp->f_blocks = TMPFS_PAGES_MAX(tmp);
+	sbp->f_bavail = sbp->f_bfree = TMPFS_PAGES_AVAIL(tmp);
+
+	freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_inuse,
+	    TMPFS_PAGES_AVAIL(tmp) * PAGE_SIZE / sizeof(struct tmpfs_node));
+
+	sbp->f_files = freenodes + tmp->tm_nodes_inuse;
+	sbp->f_ffree = freenodes;
+	/* sbp->f_owner = tmp->tn_uid; */
+
+	return 0;
+}
+
+/* --------------------------------------------------------------------- */
+
+/*
+ * tmpfs vfs operations.
+ */
+
+struct vfsops tmpfs_vfsops = {
+	.vfs_mount =			tmpfs_mount,
+	.vfs_unmount =			tmpfs_unmount,
+	.vfs_root =			tmpfs_root,
+	.vfs_statfs =			tmpfs_statfs,
+	.vfs_fhtovp =			tmpfs_fhtovp,
+};
+VFS_SET(tmpfs_vfsops, tmpfs, 0);