694a586a43
method, so that callers can indicate the minimum vnode locking requirement. This will allow some file systems to choose to return a LK_SHARED locked vnode when LK_SHARED is specified for the flags argument. This patch only adds the flag. It does not change any file system to use it and all callers specify LK_EXCLUSIVE, so file system semantics are not changed. Reviewed by: kib
421 lines
11 KiB
C
421 lines
11 KiB
C
/* $NetBSD: tmpfs_vfsops.c,v 1.10 2005/12/11 12:24:29 christos Exp $ */
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/*-
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* Copyright (c) 2005 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Julio M. Merino Vidal, developed as part of Google's Summer of Code
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* 2005 program.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Efficient memory file system.
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*
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* tmpfs is a file system that uses NetBSD's virtual memory sub-system
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* (the well-known UVM) to store file data and metadata in an efficient
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* way. This means that it does not follow the structure of an on-disk
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* file system because it simply does not need to. Instead, it uses
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* memory-specific data structures and algorithms to automatically
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* allocate and release resources.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/limits.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/kernel.h>
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#include <sys/stat.h>
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#include <sys/systm.h>
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#include <sys/sysctl.h>
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#include <vm/vm.h>
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#include <vm/vm_object.h>
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#include <vm/vm_param.h>
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#include <fs/tmpfs/tmpfs.h>
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/*
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* Default permission for root node
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*/
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#define TMPFS_DEFAULT_ROOT_MODE (S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)
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MALLOC_DEFINE(M_TMPFSMNT, "tmpfs mount", "tmpfs mount structures");
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MALLOC_DEFINE(M_TMPFSNAME, "tmpfs name", "tmpfs file names");
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/* --------------------------------------------------------------------- */
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static int tmpfs_mount(struct mount *);
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static int tmpfs_unmount(struct mount *, int);
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static int tmpfs_root(struct mount *, int flags, struct vnode **);
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static int tmpfs_fhtovp(struct mount *, struct fid *, int,
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struct vnode **);
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static int tmpfs_statfs(struct mount *, struct statfs *);
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/* --------------------------------------------------------------------- */
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static const char *tmpfs_opts[] = {
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"from", "size", "maxfilesize", "inodes", "uid", "gid", "mode", "export",
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NULL
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};
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/* --------------------------------------------------------------------- */
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static int
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tmpfs_node_ctor(void *mem, int size, void *arg, int flags)
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{
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struct tmpfs_node *node = (struct tmpfs_node *)mem;
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node->tn_gen++;
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node->tn_size = 0;
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node->tn_status = 0;
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node->tn_flags = 0;
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node->tn_links = 0;
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node->tn_vnode = NULL;
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node->tn_vpstate = 0;
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return (0);
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}
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static void
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tmpfs_node_dtor(void *mem, int size, void *arg)
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{
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struct tmpfs_node *node = (struct tmpfs_node *)mem;
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node->tn_type = VNON;
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}
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static int
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tmpfs_node_init(void *mem, int size, int flags)
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{
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struct tmpfs_node *node = (struct tmpfs_node *)mem;
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node->tn_id = 0;
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mtx_init(&node->tn_interlock, "tmpfs node interlock", NULL, MTX_DEF);
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node->tn_gen = arc4random();
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return (0);
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}
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static void
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tmpfs_node_fini(void *mem, int size)
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{
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struct tmpfs_node *node = (struct tmpfs_node *)mem;
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mtx_destroy(&node->tn_interlock);
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}
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static int
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tmpfs_mount(struct mount *mp)
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{
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struct tmpfs_mount *tmp;
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struct tmpfs_node *root;
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size_t pages;
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uint32_t nodes;
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int error;
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/* Size counters. */
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u_int nodes_max;
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u_quad_t size_max, maxfilesize;
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/* Root node attributes. */
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uid_t root_uid;
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gid_t root_gid;
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mode_t root_mode;
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struct vattr va;
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if (vfs_filteropt(mp->mnt_optnew, tmpfs_opts))
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return (EINVAL);
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if (mp->mnt_flag & MNT_UPDATE) {
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/* XXX: There is no support yet to update file system
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* settings. Should be added. */
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return EOPNOTSUPP;
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}
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printf("WARNING: TMPFS is considered to be a highly experimental "
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"feature in FreeBSD.\n");
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vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY);
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error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred);
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VOP_UNLOCK(mp->mnt_vnodecovered, 0);
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if (error)
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return (error);
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if (mp->mnt_cred->cr_ruid != 0 ||
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vfs_scanopt(mp->mnt_optnew, "gid", "%d", &root_gid) != 1)
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root_gid = va.va_gid;
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if (mp->mnt_cred->cr_ruid != 0 ||
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vfs_scanopt(mp->mnt_optnew, "uid", "%d", &root_uid) != 1)
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root_uid = va.va_uid;
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if (mp->mnt_cred->cr_ruid != 0 ||
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vfs_scanopt(mp->mnt_optnew, "mode", "%ho", &root_mode) != 1)
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root_mode = va.va_mode;
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if (vfs_scanopt(mp->mnt_optnew, "inodes", "%u", &nodes_max) != 1)
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nodes_max = 0;
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if (vfs_scanopt(mp->mnt_optnew, "size", "%qu", &size_max) != 1)
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size_max = 0;
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if (vfs_scanopt(mp->mnt_optnew, "maxfilesize", "%qu",
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&maxfilesize) != 1)
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maxfilesize = 0;
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/* Do not allow mounts if we do not have enough memory to preserve
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* the minimum reserved pages. */
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if (tmpfs_mem_info() < TMPFS_PAGES_RESERVED)
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return ENOSPC;
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/* Get the maximum number of memory pages this file system is
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* allowed to use, based on the maximum size the user passed in
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* the mount structure. A value of zero is treated as if the
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* maximum available space was requested. */
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if (size_max < PAGE_SIZE || size_max > SIZE_MAX - PAGE_SIZE)
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pages = SIZE_MAX;
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else
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pages = howmany(size_max, PAGE_SIZE);
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MPASS(pages > 0);
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if (nodes_max <= 3) {
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if (pages > UINT32_MAX - 3)
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nodes = UINT32_MAX;
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else
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nodes = pages + 3;
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} else
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nodes = nodes_max;
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MPASS(nodes >= 3);
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/* Allocate the tmpfs mount structure and fill it. */
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tmp = (struct tmpfs_mount *)malloc(sizeof(struct tmpfs_mount),
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M_TMPFSMNT, M_WAITOK | M_ZERO);
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mtx_init(&tmp->allnode_lock, "tmpfs allnode lock", NULL, MTX_DEF);
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tmp->tm_nodes_max = nodes;
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tmp->tm_nodes_inuse = 0;
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tmp->tm_maxfilesize = maxfilesize > 0 ? maxfilesize : UINT64_MAX;
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LIST_INIT(&tmp->tm_nodes_used);
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tmp->tm_pages_max = pages;
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tmp->tm_pages_used = 0;
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tmp->tm_ino_unr = new_unrhdr(2, INT_MAX, &tmp->allnode_lock);
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tmp->tm_dirent_pool = uma_zcreate("TMPFS dirent",
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sizeof(struct tmpfs_dirent),
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NULL, NULL, NULL, NULL,
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UMA_ALIGN_PTR, 0);
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tmp->tm_node_pool = uma_zcreate("TMPFS node",
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sizeof(struct tmpfs_node),
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tmpfs_node_ctor, tmpfs_node_dtor,
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tmpfs_node_init, tmpfs_node_fini,
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UMA_ALIGN_PTR, 0);
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/* Allocate the root node. */
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error = tmpfs_alloc_node(tmp, VDIR, root_uid,
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root_gid, root_mode & ALLPERMS, NULL, NULL,
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VNOVAL, &root);
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if (error != 0 || root == NULL) {
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uma_zdestroy(tmp->tm_node_pool);
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uma_zdestroy(tmp->tm_dirent_pool);
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delete_unrhdr(tmp->tm_ino_unr);
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free(tmp, M_TMPFSMNT);
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return error;
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}
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KASSERT(root->tn_id == 2, ("tmpfs root with invalid ino: %d", root->tn_id));
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tmp->tm_root = root;
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MNT_ILOCK(mp);
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mp->mnt_flag |= MNT_LOCAL;
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mp->mnt_kern_flag |= MNTK_MPSAFE;
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MNT_IUNLOCK(mp);
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mp->mnt_data = tmp;
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mp->mnt_stat.f_namemax = MAXNAMLEN;
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vfs_getnewfsid(mp);
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vfs_mountedfrom(mp, "tmpfs");
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return 0;
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}
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/* --------------------------------------------------------------------- */
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/* ARGSUSED2 */
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static int
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tmpfs_unmount(struct mount *mp, int mntflags)
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{
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int error;
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int flags = 0;
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struct tmpfs_mount *tmp;
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struct tmpfs_node *node;
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/* Handle forced unmounts. */
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if (mntflags & MNT_FORCE)
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flags |= FORCECLOSE;
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/* Finalize all pending I/O. */
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error = vflush(mp, 0, flags, curthread);
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if (error != 0)
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return error;
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tmp = VFS_TO_TMPFS(mp);
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/* Free all associated data. The loop iterates over the linked list
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* we have containing all used nodes. For each of them that is
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* a directory, we free all its directory entries. Note that after
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* freeing a node, it will automatically go to the available list,
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* so we will later have to iterate over it to release its items. */
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node = LIST_FIRST(&tmp->tm_nodes_used);
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while (node != NULL) {
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struct tmpfs_node *next;
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if (node->tn_type == VDIR) {
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struct tmpfs_dirent *de;
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de = TAILQ_FIRST(&node->tn_dir.tn_dirhead);
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while (de != NULL) {
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struct tmpfs_dirent *nde;
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nde = TAILQ_NEXT(de, td_entries);
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tmpfs_free_dirent(tmp, de, FALSE);
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de = nde;
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node->tn_size -= sizeof(struct tmpfs_dirent);
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}
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}
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next = LIST_NEXT(node, tn_entries);
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tmpfs_free_node(tmp, node);
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node = next;
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}
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uma_zdestroy(tmp->tm_dirent_pool);
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uma_zdestroy(tmp->tm_node_pool);
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delete_unrhdr(tmp->tm_ino_unr);
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mtx_destroy(&tmp->allnode_lock);
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MPASS(tmp->tm_pages_used == 0);
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MPASS(tmp->tm_nodes_inuse == 0);
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/* Throw away the tmpfs_mount structure. */
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free(mp->mnt_data, M_TMPFSMNT);
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mp->mnt_data = NULL;
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MNT_ILOCK(mp);
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mp->mnt_flag &= ~MNT_LOCAL;
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MNT_IUNLOCK(mp);
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return 0;
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}
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/* --------------------------------------------------------------------- */
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static int
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tmpfs_root(struct mount *mp, int flags, struct vnode **vpp)
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{
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int error;
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error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, flags, vpp);
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if (!error)
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(*vpp)->v_vflag |= VV_ROOT;
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return error;
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}
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/* --------------------------------------------------------------------- */
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static int
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tmpfs_fhtovp(struct mount *mp, struct fid *fhp, int flags,
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struct vnode **vpp)
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{
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boolean_t found;
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struct tmpfs_fid *tfhp;
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struct tmpfs_mount *tmp;
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struct tmpfs_node *node;
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tmp = VFS_TO_TMPFS(mp);
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tfhp = (struct tmpfs_fid *)fhp;
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if (tfhp->tf_len != sizeof(struct tmpfs_fid))
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return EINVAL;
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if (tfhp->tf_id >= tmp->tm_nodes_max)
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return EINVAL;
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found = FALSE;
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TMPFS_LOCK(tmp);
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LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) {
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if (node->tn_id == tfhp->tf_id &&
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node->tn_gen == tfhp->tf_gen) {
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found = TRUE;
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break;
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}
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}
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TMPFS_UNLOCK(tmp);
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if (found)
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return (tmpfs_alloc_vp(mp, node, LK_EXCLUSIVE, vpp));
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return (EINVAL);
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}
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/* --------------------------------------------------------------------- */
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/* ARGSUSED2 */
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static int
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tmpfs_statfs(struct mount *mp, struct statfs *sbp)
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{
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fsfilcnt_t freenodes;
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struct tmpfs_mount *tmp;
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tmp = VFS_TO_TMPFS(mp);
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sbp->f_iosize = PAGE_SIZE;
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sbp->f_bsize = PAGE_SIZE;
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sbp->f_blocks = TMPFS_PAGES_MAX(tmp);
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sbp->f_bavail = sbp->f_bfree = TMPFS_PAGES_AVAIL(tmp);
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freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_inuse,
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TMPFS_PAGES_AVAIL(tmp) * PAGE_SIZE / sizeof(struct tmpfs_node));
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sbp->f_files = freenodes + tmp->tm_nodes_inuse;
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sbp->f_ffree = freenodes;
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/* sbp->f_owner = tmp->tn_uid; */
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return 0;
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}
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/* --------------------------------------------------------------------- */
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/*
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* tmpfs vfs operations.
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*/
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struct vfsops tmpfs_vfsops = {
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.vfs_mount = tmpfs_mount,
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.vfs_unmount = tmpfs_unmount,
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.vfs_root = tmpfs_root,
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.vfs_statfs = tmpfs_statfs,
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.vfs_fhtovp = tmpfs_fhtovp,
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};
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VFS_SET(tmpfs_vfsops, tmpfs, 0);
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