namevfs.c revision d5dbd18d69de8954ab5ceb588e99d43fc9b21d46
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */
#pragma ident "%Z%%M% %I% %E% SMI" /* from S5R4 1.28 */
/*
* This file supports the vfs operations for the NAMEFS file system.
*/
#include <sys/types.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/debug.h>
#include <sys/errno.h>
#include <sys/kmem.h>
#include <sys/inline.h>
#include <sys/file.h>
#include <sys/proc.h>
#include <sys/stat.h>
#include <sys/statvfs.h>
#include <sys/mount.h>
#include <sys/sysmacros.h>
#include <sys/var.h>
#include <sys/vfs.h>
#include <sys/vnode.h>
#include <sys/mode.h>
#include <sys/pcb.h>
#include <sys/signal.h>
#include <sys/user.h>
#include <sys/uio.h>
#include <sys/cred.h>
#include <sys/fs/namenode.h>
#include <sys/stream.h>
#include <sys/strsubr.h>
#include <sys/cmn_err.h>
#include <sys/modctl.h>
#include <fs/fs_subr.h>
#include <sys/policy.h>
#include <sys/vmem.h>
#define NM_INOQUANT (64 * 1024)
/*
* Define global data structures.
*/
dev_t namedev;
int namefstype;
struct namenode *nm_filevp_hash[NM_FILEVP_HASH_SIZE];
struct vfs namevfs;
kmutex_t ntable_lock;
static vmem_t *nm_inoarena; /* vmem arena to allocate inode no's from */
static kmutex_t nm_inolock;
/*
* Functions to allocate node id's starting from 1. Based on vmem routines.
* The vmem arena is extended in NM_INOQUANT chunks.
*/
uint64_t
namenodeno_alloc(void)
{
uint64_t nno;
mutex_enter(&nm_inolock);
nno = (uint64_t)(uintptr_t)
vmem_alloc(nm_inoarena, 1, VM_NOSLEEP + VM_FIRSTFIT);
if (nno == 0) {
(void) vmem_add(nm_inoarena, (void *)(vmem_size(nm_inoarena,
VMEM_ALLOC | VMEM_FREE) + 1), NM_INOQUANT, VM_SLEEP);
nno = (uint64_t)(uintptr_t)
vmem_alloc(nm_inoarena, 1, VM_SLEEP + VM_FIRSTFIT);
ASSERT(nno != 0);
}
mutex_exit(&nm_inolock);
ASSERT32(nno <= ULONG_MAX);
return (nno);
}
static void
namenodeno_init(void)
{
nm_inoarena = vmem_create("namefs_inodes", (void *)1, NM_INOQUANT, 1,
NULL, NULL, NULL, 1, VM_SLEEP);
mutex_init(&nm_inolock, NULL, MUTEX_DEFAULT, NULL);
}
void
namenodeno_free(uint64_t nn)
{
void *vaddr = (void *)(uintptr_t)nn;
ASSERT32((uint64_t)(uintptr_t)vaddr == nn);
mutex_enter(&nm_inolock);
vmem_free(nm_inoarena, vaddr, 1);
mutex_exit(&nm_inolock);
}
/*
* Insert a namenode into the nm_filevp_hash table.
*
* Each link has a unique namenode with a unique nm_mountvp field.
* The nm_filevp field of the namenode need not be unique, since a
* file descriptor may be mounted to multiple nodes at the same time.
* We hash on nm_filevp since that's what discriminates the searches
* in namefind() and nm_unmountall().
*/
void
nameinsert(struct namenode *nodep)
{
struct namenode **bucket;
ASSERT(MUTEX_HELD(&ntable_lock));
bucket = NM_FILEVP_HASH(nodep->nm_filevp);
nodep->nm_nextp = *bucket;
*bucket = nodep;
}
/*
* Remove a namenode from the hash table, if present.
*/
void
nameremove(struct namenode *nodep)
{
struct namenode *np, **npp;
ASSERT(MUTEX_HELD(&ntable_lock));
for (npp = NM_FILEVP_HASH(nodep->nm_filevp); (np = *npp) != NULL;
npp = &np->nm_nextp) {
if (np == nodep) {
*npp = np->nm_nextp;
return;
}
}
}
/*
* Search for a namenode that has a nm_filevp == vp and nm_mountpt == mnt.
* If mnt is NULL, return the first link with nm_filevp of vp.
* Returns namenode pointer on success, NULL on failure.
*/
struct namenode *
namefind(vnode_t *vp, vnode_t *mnt)
{
struct namenode *np;
ASSERT(MUTEX_HELD(&ntable_lock));
for (np = *NM_FILEVP_HASH(vp); np != NULL; np = np->nm_nextp)
if (np->nm_filevp == vp &&
(mnt == NULL || np->nm_mountpt == mnt))
break;
return (np);
}
/*
* Force the unmouting of a file descriptor from ALL of the nodes
* that it was mounted to.
* At the present time, the only usage for this routine is in the
* event one end of a pipe was mounted. At the time the unmounted
* end gets closed down, the mounted end is forced to be unmounted.
*
* This routine searches the namenode hash list for all namenodes
* that have a nm_filevp field equal to vp. Each time one is found,
* the dounmount() routine is called. This causes the nm_unmount()
* routine to be called and thus, the file descriptor is unmounted
* from the node.
*
* At the start of this routine, the reference count for vp is
* incremented to protect the vnode from being released in the
* event the mount was the only thing keeping the vnode active.
* If that is the case, the VOP_CLOSE operation is applied to
* the vnode, prior to it being released.
*/
static int
nm_umountall(vnode_t *vp, cred_t *crp)
{
vfs_t *vfsp;
struct namenode *nodep;
int error = 0;
int realerr = 0;
/*
* For each namenode that is associated with the file:
* If the v_vfsp field is not namevfs, dounmount it. Otherwise,
* it was created in nm_open() and will be released in time.
* The following loop replicates some code from nm_find. That
* routine can't be used as is since the list isn't strictly
* consumed as it is traversed.
*/
mutex_enter(&ntable_lock);
nodep = *NM_FILEVP_HASH(vp);
while (nodep) {
if (nodep->nm_filevp == vp &&
(vfsp = NMTOV(nodep)->v_vfsp) != NULL && vfsp != &namevfs) {
/*
* If the vn_vfswlock fails, skip the vfs since
* somebody else may be unmounting it.
*/
if (vn_vfswlock(vfsp->vfs_vnodecovered)) {
realerr = EBUSY;
nodep = nodep->nm_nextp;
continue;
}
/*
* Can't hold ntable_lock across call to do_unmount
* because nm_unmount tries to acquire it. This means
* there is a window where another mount of vp can
* happen so it is possible that after nm_unmountall
* there are still some mounts. This situation existed
* without MT locking because dounmount can sleep
* so another mount could happen during that time.
* This situation is unlikely and doesn't really cause
* any problems.
*/
mutex_exit(&ntable_lock);
if ((error = dounmount(vfsp, 0, crp)) != 0)
realerr = error;
mutex_enter(&ntable_lock);
/*
* Since we dropped the ntable_lock, we
* have to start over from the beginning.
* If for some reasons dounmount() fails,
* start from beginning means that we will keep on
* trying unless another thread unmounts it for us.
*/
nodep = *NM_FILEVP_HASH(vp);
} else
nodep = nodep->nm_nextp;
}
mutex_exit(&ntable_lock);
return (realerr);
}
/*
* Force the unmouting of a file descriptor from ALL of the nodes
* that it was mounted to. XXX: fifo_close() calls this routine.
*
* nm_umountall() may return EBUSY.
* nm_unmountall() will keep on trying until it succeeds.
*/
int
nm_unmountall(vnode_t *vp, cred_t *crp)
{
int error;
/*
* Nm_umuontall() returns only if it succeeds or
* return with error EBUSY. If EBUSY, that means
* it cannot acquire the lock on the covered vnode,
* and we will keep on trying.
*/
for (;;) {
error = nm_umountall(vp, crp);
if (error != EBUSY)
break;
delay(1); /* yield cpu briefly, then try again */
}
return (error);
}
/*
* Mount a file descriptor onto the node in the file system.
* Create a new vnode, update the attributes with info from the
* file descriptor and the mount point. The mask, mode, uid, gid,
* atime, mtime and ctime are taken from the mountpt. Link count is
* set to one, the file system id is namedev and nodeid is unique
* for each mounted object. Other attributes are taken from mount point.
* Make sure user is owner (or root) with write permissions on mount point.
* Hash the new vnode and return 0.
* Upon entry to this routine, the file descriptor is in the
* fd field of a struct namefd. Copy that structure from user
* space and retrieve the file descriptor.
*/
static int
nm_mount(vfs_t *vfsp, vnode_t *mvp, struct mounta *uap, cred_t *crp)
{
struct namefd namefdp;
struct vnode *filevp; /* file descriptor vnode */
struct file *fp;
struct vnode *newvp; /* vnode representing this mount */
struct namenode *nodep; /* namenode for this mount */
struct vattr filevattr; /* attributes of file dec. */
struct vattr *vattrp; /* attributes of this mount */
char *resource_name;
char *resource_nodetype;
statvfs64_t *svfsp;
int error = 0;
/*
* Get the file descriptor from user space.
* Make sure the file descriptor is valid and has an
* associated file pointer.
* If so, extract the vnode from the file pointer.
*/
if (uap->datalen != sizeof (struct namefd))
return (EINVAL);
if (copyin(uap->dataptr, &namefdp, uap->datalen))
return (EFAULT);
if ((fp = getf(namefdp.fd)) == NULL)
return (EBADF);
/*
* If the mount point already has something mounted
* on it, disallow this mount. (This restriction may
* be removed in a later release).
* Or unmount has completed but the namefs ROOT vnode
* count has not decremented to zero, disallow this mount.
*/
mutex_enter(&mvp->v_lock);
if ((mvp->v_flag & VROOT) || (mvp->v_vfsp == &namevfs)) {
mutex_exit(&mvp->v_lock);
releasef(namefdp.fd);
return (EBUSY);
}
mutex_exit(&mvp->v_lock);
filevp = fp->f_vnode;
if (filevp->v_type == VDIR || filevp->v_type == VPORT) {
releasef(namefdp.fd);
return (EINVAL);
}
/*
* If the fd being mounted refers to neither a door nor a stream,
* make sure the caller is privileged.
*/
if (filevp->v_type != VDOOR && filevp->v_stream == NULL) {
if (secpolicy_fs_mount(crp, filevp, vfsp) != 0) {
/* fd is neither a stream nor a door */
releasef(namefdp.fd);
return (EINVAL);
}
}
/*
* Make sure the file descriptor is not the root of some
* file system.
* If it's not, create a reference and allocate a namenode
* to represent this mount request.
*/
if (filevp->v_flag & VROOT) {
releasef(namefdp.fd);
return (EBUSY);
}
nodep = kmem_zalloc(sizeof (struct namenode), KM_SLEEP);
mutex_init(&nodep->nm_lock, NULL, MUTEX_DEFAULT, NULL);
vattrp = &nodep->nm_vattr;
vattrp->va_mask = AT_ALL;
if (error = VOP_GETATTR(mvp, vattrp, 0, crp))
goto out;
filevattr.va_mask = AT_ALL;
if (error = VOP_GETATTR(filevp, &filevattr, 0, crp))
goto out;
/*
* Make sure the user is the owner of the mount point
* or has sufficient privileges.
*/
if (error = secpolicy_vnode_owner(crp, vattrp->va_uid))
goto out;
/*
* Make sure the user has write permissions on the
* mount point (or has sufficient privileges).
*/
if (!(vattrp->va_mode & VWRITE) &&
secpolicy_vnode_access(crp, mvp, vattrp->va_uid, VWRITE) != 0) {
error = EACCES;
goto out;
}
/*
* If the file descriptor has file/record locking, don't
* allow the mount to succeed.
*/
if (vn_has_flocks(filevp)) {
error = EACCES;
goto out;
}
/*
* Initialize the namenode.
*/
if (filevp->v_stream) {
struct stdata *stp = filevp->v_stream;
mutex_enter(&stp->sd_lock);
stp->sd_flag |= STRMOUNT;
mutex_exit(&stp->sd_lock);
}
nodep->nm_filevp = filevp;
mutex_enter(&fp->f_tlock);
fp->f_count++;
mutex_exit(&fp->f_tlock);
releasef(namefdp.fd);
nodep->nm_filep = fp;
nodep->nm_mountpt = mvp;
/*
* The attributes for the mounted file descriptor were initialized
* above by applying VOP_GETATTR to the mount point. Some of
* the fields of the attributes structure will be overwritten
* by the attributes from the file descriptor.
*/
vattrp->va_type = filevattr.va_type;
vattrp->va_fsid = namedev;
vattrp->va_nodeid = namenodeno_alloc();
vattrp->va_nlink = 1;
vattrp->va_size = filevattr.va_size;
vattrp->va_rdev = filevattr.va_rdev;
vattrp->va_blksize = filevattr.va_blksize;
vattrp->va_nblocks = filevattr.va_nblocks;
vattrp->va_seq = 0;
/*
* Initialize new vnode structure for the mounted file descriptor.
*/
nodep->nm_vnode = vn_alloc(KM_SLEEP);
newvp = NMTOV(nodep);
newvp->v_flag = filevp->v_flag | VROOT | VNOMAP | VNOSWAP;
vn_setops(newvp, nm_vnodeops);
newvp->v_vfsp = vfsp;
newvp->v_stream = filevp->v_stream;
newvp->v_type = filevp->v_type;
newvp->v_rdev = filevp->v_rdev;
newvp->v_data = (caddr_t)nodep;
vn_exists(newvp);
/*
* Initialize the vfs structure.
*/
vfsp->vfs_vnodecovered = NULL;
vfsp->vfs_flag |= VFS_UNLINKABLE;
vfsp->vfs_bsize = 1024;
vfsp->vfs_fstype = namefstype;
vfs_make_fsid(&vfsp->vfs_fsid, namedev, namefstype);
vfsp->vfs_data = (caddr_t)nodep;
vfsp->vfs_dev = namedev;
vfsp->vfs_bcount = 0;
/*
* Set the name we mounted from.
*/
switch (filevp->v_type) {
case VPROC: /* VOP_GETATTR() translates this to VREG */
case VREG: resource_nodetype = "file"; break;
case VDIR: resource_nodetype = "directory"; break;
case VBLK: resource_nodetype = "device"; break;
case VCHR: resource_nodetype = "device"; break;
case VLNK: resource_nodetype = "link"; break;
case VFIFO: resource_nodetype = "fifo"; break;
case VDOOR: resource_nodetype = "door"; break;
case VSOCK: resource_nodetype = "socket"; break;
default: resource_nodetype = "resource"; break;
}
#define RESOURCE_NAME_SZ 128 /* Maximum length of the resource name */
resource_name = kmem_alloc(RESOURCE_NAME_SZ, KM_SLEEP);
svfsp = kmem_alloc(sizeof (statvfs64_t), KM_SLEEP);
error = VFS_STATVFS(filevp->v_vfsp, svfsp);
if (error == 0) {
(void) snprintf(resource_name, RESOURCE_NAME_SZ,
"unspecified_%s_%s", svfsp->f_basetype, resource_nodetype);
} else {
(void) snprintf(resource_name, RESOURCE_NAME_SZ,
"unspecified_%s", resource_nodetype);
}
vfs_setresource(vfsp, resource_name);
kmem_free(svfsp, sizeof (statvfs64_t));
kmem_free(resource_name, RESOURCE_NAME_SZ);
#undef RESOURCE_NAME_SZ
/*
* Insert the namenode.
*/
mutex_enter(&ntable_lock);
nameinsert(nodep);
mutex_exit(&ntable_lock);
return (0);
out:
releasef(namefdp.fd);
kmem_free(nodep, sizeof (struct namenode));
return (error);
}
/*
* Unmount a file descriptor from a node in the file system.
* If the user is not the owner of the file and is not privileged,
* the request is denied.
* Otherwise, remove the namenode from the hash list.
* If the mounted file descriptor was that of a stream and this
* was the last mount of the stream, turn off the STRMOUNT flag.
* If the rootvp is referenced other than through the mount,
* nm_inactive will clean up.
*/
static int
nm_unmount(vfs_t *vfsp, int flag, cred_t *crp)
{
struct namenode *nodep = (struct namenode *)vfsp->vfs_data;
vnode_t *vp, *thisvp;
struct file *fp = NULL;
ASSERT((nodep->nm_flag & NMNMNT) == 0);
/*
* forced unmount is not supported by this file system
* and thus, ENOTSUP, is being returned.
*/
if (flag & MS_FORCE) {
return (ENOTSUP);
}
vp = nodep->nm_filevp;
mutex_enter(&nodep->nm_lock);
if (secpolicy_vnode_owner(crp, nodep->nm_vattr.va_uid) != 0) {
mutex_exit(&nodep->nm_lock);
return (EPERM);
}
mutex_exit(&nodep->nm_lock);
mutex_enter(&ntable_lock);
nameremove(nodep);
thisvp = NMTOV(nodep);
mutex_enter(&thisvp->v_lock);
if (thisvp->v_count-- == 1) {
fp = nodep->nm_filep;
mutex_exit(&thisvp->v_lock);
vn_invalid(thisvp);
vn_free(thisvp);
namenodeno_free(nodep->nm_vattr.va_nodeid);
kmem_free(nodep, sizeof (struct namenode));
} else {
thisvp->v_flag &= ~VROOT;
thisvp->v_vfsp = &namevfs;
mutex_exit(&thisvp->v_lock);
}
if (namefind(vp, NULLVP) == NULL && vp->v_stream) {
struct stdata *stp = vp->v_stream;
mutex_enter(&stp->sd_lock);
stp->sd_flag &= ~STRMOUNT;
mutex_exit(&stp->sd_lock);
}
mutex_exit(&ntable_lock);
if (fp != NULL)
(void) closef(fp);
return (0);
}
/*
* Create a reference to the root of a mounted file descriptor.
* This routine is called from lookupname() in the event a path
* is being searched that has a mounted file descriptor in it.
*/
static int
nm_root(vfs_t *vfsp, vnode_t **vpp)
{
struct namenode *nodep = (struct namenode *)vfsp->vfs_data;
struct vnode *vp = NMTOV(nodep);
VN_HOLD(vp);
*vpp = vp;
return (0);
}
/*
* Return in sp the status of this file system.
*/
static int
nm_statvfs(vfs_t *vfsp, struct statvfs64 *sp)
{
dev32_t d32;
bzero(sp, sizeof (*sp));
sp->f_bsize = 1024;
sp->f_frsize = 1024;
(void) cmpldev(&d32, vfsp->vfs_dev);
sp->f_fsid = d32;
(void) strcpy(sp->f_basetype, vfssw[vfsp->vfs_fstype].vsw_name);
sp->f_flag = vf_to_stf(vfsp->vfs_flag);
return (0);
}
/*
* Since this file system has no disk blocks of its own, apply
* the VOP_FSYNC operation on the mounted file descriptor.
*/
static int
nm_sync(vfs_t *vfsp, short flag, cred_t *crp)
{
struct namenode *nodep;
if (vfsp == NULL)
return (0);
nodep = (struct namenode *)vfsp->vfs_data;
if (flag & SYNC_CLOSE)
return (nm_umountall(nodep->nm_filevp, crp));
return (VOP_FSYNC(nodep->nm_filevp, FSYNC, crp));
}
/*
* File system initialization routine. Save the file system type,
* establish a file system device number and initialize nm_filevp_hash[].
*/
int
nameinit(int fstype, char *name)
{
static const fs_operation_def_t nm_vfsops_template[] = {
VFSNAME_MOUNT, nm_mount,
VFSNAME_UNMOUNT, nm_unmount,
VFSNAME_ROOT, nm_root,
VFSNAME_STATVFS, nm_statvfs,
VFSNAME_SYNC, (fs_generic_func_p) nm_sync,
NULL, NULL
};
static const fs_operation_def_t nm_dummy_vfsops_template[] = {
VFSNAME_STATVFS, nm_statvfs,
VFSNAME_SYNC, (fs_generic_func_p) nm_sync,
NULL, NULL
};
int error;
int dev;
vfsops_t *namefs_vfsops;
vfsops_t *dummy_vfsops;
error = vfs_setfsops(fstype, nm_vfsops_template, &namefs_vfsops);
if (error != 0) {
cmn_err(CE_WARN, "nameinit: bad vfs ops template");
return (error);
}
error = vfs_makefsops(nm_dummy_vfsops_template, &dummy_vfsops);
if (error != 0) {
(void) vfs_freevfsops_by_type(fstype);
cmn_err(CE_WARN, "nameinit: bad dummy vfs ops template");
return (error);
}
error = vn_make_ops(name, nm_vnodeops_template, &nm_vnodeops);
if (error != 0) {
(void) vfs_freevfsops_by_type(fstype);
vfs_freevfsops(dummy_vfsops);
cmn_err(CE_WARN, "nameinit: bad vnode ops template");
return (error);
}
namefstype = fstype;
if ((dev = getudev()) == (major_t)-1) {
cmn_err(CE_WARN, "nameinit: can't get unique device");
dev = 0;
}
mutex_init(&ntable_lock, NULL, MUTEX_DEFAULT, NULL);
namedev = makedevice(dev, 0);
bzero(nm_filevp_hash, sizeof (nm_filevp_hash));
vfs_setops(&namevfs, dummy_vfsops);
namevfs.vfs_vnodecovered = NULL;
namevfs.vfs_bsize = 1024;
namevfs.vfs_fstype = namefstype;
vfs_make_fsid(&namevfs.vfs_fsid, namedev, namefstype);
namevfs.vfs_dev = namedev;
return (0);
}
static mntopts_t nm_mntopts = {
NULL,
0
};
static vfsdef_t vfw = {
VFSDEF_VERSION,
"namefs",
nameinit,
VSW_HASPROTO,
&nm_mntopts
};
/*
* Module linkage information for the kernel.
*/
static struct modlfs modlfs = {
&mod_fsops, "filesystem for namefs", &vfw
};
static struct modlinkage modlinkage = {
MODREV_1, (void *)&modlfs, NULL
};
int
_init(void)
{
namenodeno_init();
return (mod_install(&modlinkage));
}
int
_fini(void)
{
return (EBUSY);
}
int
_info(struct modinfo *modinfop)
{
return (mod_info(&modlinkage, modinfop));
}