465 lines
12 KiB
C
465 lines
12 KiB
C
/* $NetBSD: tmpfs_vfsops.c,v 1.44 2008/07/29 09:10:09 pooka Exp $ */
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/*
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* Copyright (c) 2005, 2006, 2007 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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__KERNEL_RCSID(0, "$NetBSD: tmpfs_vfsops.c,v 1.44 2008/07/29 09:10:09 pooka Exp $");
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#include <sys/param.h>
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#include <sys/types.h>
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#include <sys/kmem.h>
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#include <sys/mount.h>
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#include <sys/stat.h>
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#include <sys/systm.h>
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#include <sys/vnode.h>
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#include <sys/proc.h>
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#include <sys/module.h>
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#include <miscfs/genfs/genfs.h>
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#include <fs/tmpfs/tmpfs.h>
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#include <fs/tmpfs/tmpfs_args.h>
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MODULE(MODULE_CLASS_VFS, tmpfs, NULL);
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/* --------------------------------------------------------------------- */
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static int tmpfs_mount(struct mount *, const char *, void *, size_t *);
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static int tmpfs_start(struct mount *, int);
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static int tmpfs_unmount(struct mount *, int);
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static int tmpfs_root(struct mount *, struct vnode **);
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static int tmpfs_vget(struct mount *, ino_t, struct vnode **);
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static int tmpfs_fhtovp(struct mount *, struct fid *, struct vnode **);
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static int tmpfs_vptofh(struct vnode *, struct fid *, size_t *);
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static int tmpfs_statvfs(struct mount *, struct statvfs *);
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static int tmpfs_sync(struct mount *, int, kauth_cred_t);
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static void tmpfs_init(void);
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static void tmpfs_done(void);
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static int tmpfs_snapshot(struct mount *, struct vnode *,
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struct timespec *);
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/* --------------------------------------------------------------------- */
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static int
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tmpfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
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{
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struct lwp *l = curlwp;
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int error;
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ino_t nodes;
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size_t pages;
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struct tmpfs_mount *tmp;
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struct tmpfs_node *root;
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struct tmpfs_args *args = data;
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if (*data_len < sizeof *args)
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return EINVAL;
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/* Handle retrieval of mount point arguments. */
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if (mp->mnt_flag & MNT_GETARGS) {
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if (mp->mnt_data == NULL)
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return EIO;
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tmp = VFS_TO_TMPFS(mp);
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args->ta_version = TMPFS_ARGS_VERSION;
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args->ta_nodes_max = tmp->tm_nodes_max;
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args->ta_size_max = tmp->tm_pages_max * PAGE_SIZE;
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root = tmp->tm_root;
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args->ta_root_uid = root->tn_uid;
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args->ta_root_gid = root->tn_gid;
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args->ta_root_mode = root->tn_mode;
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*data_len = sizeof *args;
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return 0;
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}
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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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if (args->ta_version != TMPFS_ARGS_VERSION)
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return EINVAL;
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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(true) < TMPFS_PAGES_RESERVED)
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return EINVAL;
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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 (args->ta_size_max < PAGE_SIZE || args->ta_size_max >= SIZE_MAX)
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pages = SIZE_MAX;
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else
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pages = args->ta_size_max / PAGE_SIZE +
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(args->ta_size_max % PAGE_SIZE == 0 ? 0 : 1);
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if (pages > INT_MAX)
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pages = INT_MAX;
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KASSERT(pages > 0);
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if (args->ta_nodes_max <= 3)
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nodes = 3 + pages * PAGE_SIZE / 1024;
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else
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nodes = args->ta_nodes_max;
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if (nodes > INT_MAX)
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nodes = INT_MAX;
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KASSERT(nodes >= 3);
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/* Allocate the tmpfs mount structure and fill it. */
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tmp = kmem_alloc(sizeof(struct tmpfs_mount), KM_SLEEP);
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if (tmp == NULL)
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return ENOMEM;
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tmp->tm_nodes_max = nodes;
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tmp->tm_nodes_cnt = 0;
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LIST_INIT(&tmp->tm_nodes);
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mutex_init(&tmp->tm_lock, MUTEX_DEFAULT, IPL_NONE);
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tmp->tm_pages_max = pages;
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tmp->tm_pages_used = 0;
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tmpfs_pool_init(&tmp->tm_dirent_pool, sizeof(struct tmpfs_dirent),
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"dirent", tmp);
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tmpfs_pool_init(&tmp->tm_node_pool, sizeof(struct tmpfs_node),
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"node", tmp);
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tmpfs_str_pool_init(&tmp->tm_str_pool, tmp);
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/* Allocate the root node. */
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error = tmpfs_alloc_node(tmp, VDIR, args->ta_root_uid,
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args->ta_root_gid, args->ta_root_mode & ALLPERMS, NULL, NULL,
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VNOVAL, &root);
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KASSERT(error == 0 && root != NULL);
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root->tn_links++;
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tmp->tm_root = root;
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mp->mnt_data = tmp;
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mp->mnt_flag |= MNT_LOCAL;
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mp->mnt_stat.f_namemax = MAXNAMLEN;
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mp->mnt_fs_bshift = PAGE_SHIFT;
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mp->mnt_dev_bshift = DEV_BSHIFT;
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mp->mnt_iflag |= IMNT_MPSAFE;
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vfs_getnewfsid(mp);
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return set_statvfs_info(path, UIO_USERSPACE, "tmpfs", UIO_SYSSPACE,
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mp->mnt_op->vfs_name, mp, l);
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}
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/* --------------------------------------------------------------------- */
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static int
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tmpfs_start(struct mount *mp, int flags)
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{
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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, NULL, flags);
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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);
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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_spec.tn_dir.tn_dir);
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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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tmpfs_pool_destroy(&tmp->tm_dirent_pool);
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tmpfs_pool_destroy(&tmp->tm_node_pool);
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tmpfs_str_pool_destroy(&tmp->tm_str_pool);
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KASSERT(tmp->tm_pages_used == 0);
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/* Throw away the tmpfs_mount structure. */
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mutex_destroy(&tmp->tm_lock);
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kmem_free(tmp, sizeof(*tmp));
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mp->mnt_data = NULL;
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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, struct vnode **vpp)
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{
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return tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, vpp);
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}
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/* --------------------------------------------------------------------- */
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static int
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tmpfs_vget(struct mount *mp, ino_t ino,
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struct vnode **vpp)
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{
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printf("tmpfs_vget called; need for it unknown yet\n");
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return EOPNOTSUPP;
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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, struct vnode **vpp)
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{
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bool found;
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struct tmpfs_fid tfh;
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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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if (fhp->fid_len != sizeof(struct tmpfs_fid))
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return EINVAL;
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memcpy(&tfh, fhp, sizeof(struct tmpfs_fid));
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if (tfh.tf_id >= tmp->tm_nodes_max)
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return EINVAL;
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found = false;
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mutex_enter(&tmp->tm_lock);
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LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) {
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if (node->tn_id == tfh.tf_id &&
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node->tn_gen == tfh.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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mutex_exit(&tmp->tm_lock);
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/* XXXAD nothing to prevent 'node' from being removed. */
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return found ? tmpfs_alloc_vp(mp, node, vpp) : EINVAL;
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}
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/* --------------------------------------------------------------------- */
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static int
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tmpfs_vptofh(struct vnode *vp, struct fid *fhp, size_t *fh_size)
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{
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struct tmpfs_fid tfh;
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struct tmpfs_node *node;
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if (*fh_size < sizeof(struct tmpfs_fid)) {
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*fh_size = sizeof(struct tmpfs_fid);
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return E2BIG;
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}
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*fh_size = sizeof(struct tmpfs_fid);
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node = VP_TO_TMPFS_NODE(vp);
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memset(&tfh, 0, sizeof(tfh));
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tfh.tf_len = sizeof(struct tmpfs_fid);
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tfh.tf_gen = node->tn_gen;
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tfh.tf_id = node->tn_id;
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memcpy(fhp, &tfh, sizeof(tfh));
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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_statvfs(struct mount *mp, struct statvfs *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 = sbp->f_frsize = 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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sbp->f_bresvd = 0;
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freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_cnt,
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TMPFS_PAGES_AVAIL(tmp) * PAGE_SIZE / sizeof(struct tmpfs_node));
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sbp->f_files = tmp->tm_nodes_cnt + freenodes;
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sbp->f_favail = sbp->f_ffree = freenodes;
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sbp->f_fresvd = 0;
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copy_statvfs_info(sbp, mp);
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return 0;
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}
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/* --------------------------------------------------------------------- */
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/* ARGSUSED0 */
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static int
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tmpfs_sync(struct mount *mp, int waitfor,
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kauth_cred_t uc)
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{
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return 0;
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}
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/* --------------------------------------------------------------------- */
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static void
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tmpfs_init(void)
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{
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}
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/* --------------------------------------------------------------------- */
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static void
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tmpfs_done(void)
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{
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}
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/* --------------------------------------------------------------------- */
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static int
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tmpfs_snapshot(struct mount *mp, struct vnode *vp,
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struct timespec *ctime)
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{
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return EOPNOTSUPP;
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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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extern const struct vnodeopv_desc tmpfs_fifoop_opv_desc;
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extern const struct vnodeopv_desc tmpfs_specop_opv_desc;
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extern const struct vnodeopv_desc tmpfs_vnodeop_opv_desc;
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const struct vnodeopv_desc * const tmpfs_vnodeopv_descs[] = {
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&tmpfs_fifoop_opv_desc,
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&tmpfs_specop_opv_desc,
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&tmpfs_vnodeop_opv_desc,
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NULL,
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};
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struct vfsops tmpfs_vfsops = {
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MOUNT_TMPFS, /* vfs_name */
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sizeof (struct tmpfs_args),
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tmpfs_mount, /* vfs_mount */
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tmpfs_start, /* vfs_start */
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tmpfs_unmount, /* vfs_unmount */
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tmpfs_root, /* vfs_root */
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(void *)eopnotsupp, /* vfs_quotactl */
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tmpfs_statvfs, /* vfs_statvfs */
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tmpfs_sync, /* vfs_sync */
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tmpfs_vget, /* vfs_vget */
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tmpfs_fhtovp, /* vfs_fhtovp */
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tmpfs_vptofh, /* vfs_vptofh */
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tmpfs_init, /* vfs_init */
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NULL, /* vfs_reinit */
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tmpfs_done, /* vfs_done */
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NULL, /* vfs_mountroot */
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tmpfs_snapshot, /* vfs_snapshot */
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vfs_stdextattrctl, /* vfs_extattrctl */
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(void *)eopnotsupp, /* vfs_suspendctl */
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genfs_renamelock_enter,
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genfs_renamelock_exit,
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(void *)eopnotsupp,
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tmpfs_vnodeopv_descs,
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0, /* vfs_refcount */
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{ NULL, NULL },
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};
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static int
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tmpfs_modcmd(modcmd_t cmd, void *arg)
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{
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switch (cmd) {
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case MODULE_CMD_INIT:
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return vfs_attach(&tmpfs_vfsops);
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case MODULE_CMD_FINI:
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return vfs_detach(&tmpfs_vfsops);
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default:
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return ENOTTY;
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}
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}
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