fs/coda/coda_vfsops.c

/*-
 *             Coda: an Experimental Distributed File System
 *                              Release 3.1
 *
 *           Copyright (c) 1987-1998 Carnegie Mellon University
 *                          All Rights Reserved
 *
 * Permission  to  use, copy, modify and distribute this software and its
 * documentation is hereby granted,  provided  that  both  the  copyright
 * notice  and  this  permission  notice  appear  in  all  copies  of the
 * software, derivative works or  modified  versions,  and  any  portions
 * thereof, and that both notices appear in supporting documentation, and
 * that credit is given to Carnegie Mellon University  in  all  documents
 * and publicity pertaining to direct or indirect use of this code or its
 * derivatives.
 *
 * CODA IS AN EXPERIMENTAL SOFTWARE SYSTEM AND IS  KNOWN  TO  HAVE  BUGS,
 * SOME  OF  WHICH MAY HAVE SERIOUS CONSEQUENCES.  CARNEGIE MELLON ALLOWS
 * FREE USE OF THIS SOFTWARE IN ITS "AS IS" CONDITION.   CARNEGIE  MELLON
 * DISCLAIMS  ANY  LIABILITY  OF  ANY  KIND  FOR  ANY  DAMAGES WHATSOEVER
 * RESULTING DIRECTLY OR INDIRECTLY FROM THE USE OF THIS SOFTWARE  OR  OF
 * ANY DERIVATIVE WORK.
 *
 * Carnegie  Mellon  encourages  users  of  this  software  to return any
 * improvements or extensions that  they  make,  and  to  grant  Carnegie
 * Mellon the rights to redistribute these changes without encumbrance.
 *
 *  	@(#) src/sys/cfs/coda_vfsops.c,v 1.1.1.1 1998/08/29 21:14:52 rvb Exp $
 */

/*-
 * Mach Operating System
 * Copyright (c) 1989 Carnegie-Mellon University
 * All rights reserved.  The CMU software License Agreement specifies
 * the terms and conditions for use and redistribution.
 */

/*
 * This code was written for the Coda filesystem at Carnegie Mellon
 * University.  Contributers include David Steere, James Kistler, and
 * M. Satyanarayanan.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD: head/sys/fs/coda/coda_vfsops.c 176139 2008-02-10 11:18:12Z rwatson $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/proc.h>

#include <fs/coda/coda.h>
#include <fs/coda/cnode.h>
#include <fs/coda/coda_vfsops.h>
#include <fs/coda/coda_venus.h>
#include <fs/coda/coda_subr.h>
#include <fs/coda/coda_opstats.h>

MALLOC_DEFINE(M_CODA, "coda", "Various Coda Structures");

int codadebug = 0;
int coda_vfsop_print_entry = 0;
#define	ENTRY do {							\
	if (coda_vfsop_print_entry)					\
		myprintf(("Entered %s\n", __func__));			\
} while (0)

struct vnode *coda_ctlvp;

/*
 * Structure to keep statistics of internally generated/satisfied calls.
 */
static struct coda_op_stats coda_vfsopstats[CODA_VFSOPS_SIZE];

#define	MARK_ENTRY(op)		(coda_vfsopstats[op].entries++)
#define	MARK_INT_SAT(op)	(coda_vfsopstats[op].sat_intrn++)
#define	MARK_INT_FAIL(op)	(coda_vfsopstats[op].unsat_intrn++)
#define	MARK_INT_GEN(op)	(coda_vfsopstats[op].gen_intrn++)

int
coda_vfsopstats_init(void)
{
	int i;

	for (i=0; i<CODA_VFSOPS_SIZE;i++) {
		coda_vfsopstats[i].opcode = i;
		coda_vfsopstats[i].entries = 0;
		coda_vfsopstats[i].sat_intrn = 0;
		coda_vfsopstats[i].unsat_intrn = 0;
		coda_vfsopstats[i].gen_intrn = 0;
	}
	return (0);
}

static const char *coda_opts[] = { "from", NULL };
/*
 * cfs mount vfsop
 *
 * Set up mount info record and attach it to vfs struct.
 */
/*ARGSUSED*/
int
coda_mount(struct mount *vfsp, struct thread *td)
{
	struct vnode *dvp;
	struct cnode *cp;
	struct cdev *dev;
	struct coda_mntinfo *mi;
	struct vnode *rootvp;
	CodaFid rootfid = INVAL_FID;
	CodaFid ctlfid = CTL_FID;
	int error;
	struct nameidata ndp;
	ENTRY;
	char *from;

	if (vfs_filteropt(vfsp->mnt_optnew, coda_opts))
		return (EINVAL);
	from = vfs_getopts(vfsp->mnt_optnew, "from", &error);
	if (error)
		return (error);
	coda_vfsopstats_init();
	coda_vnodeopstats_init();
	MARK_ENTRY(CODA_MOUNT_STATS);
	if (CODA_MOUNTED(vfsp)) {
		MARK_INT_FAIL(CODA_MOUNT_STATS);
		return (EBUSY);
	}

	/*
	 * Validate mount device.  Similar to getmdev().
	 */
	NDINIT(&ndp, LOOKUP, FOLLOW, UIO_SYSSPACE, from, td);
	error = namei(&ndp);
	dvp = ndp.ni_vp;
	if (error) {
		MARK_INT_FAIL(CODA_MOUNT_STATS);
		return (error);
	}
	if (dvp->v_type != VCHR) {
		MARK_INT_FAIL(CODA_MOUNT_STATS);
		vrele(dvp);
		NDFREE(&ndp, NDF_ONLY_PNBUF);
		return (ENXIO);
	}
	dev = dvp->v_rdev;
	vrele(dvp);
	NDFREE(&ndp, NDF_ONLY_PNBUF);

	/*
	 * Initialize the mount record and link it to the vfs struct.
	 */
	mi = dev2coda_mntinfo(dev);
	if (!mi) {
		MARK_INT_FAIL(CODA_MOUNT_STATS);
		printf("Coda mount: %s is not a cfs device\n", from);
		return (ENXIO);
	}
	if (!VC_OPEN(&mi->mi_vcomm)) {
		MARK_INT_FAIL(CODA_MOUNT_STATS);
		return (ENODEV);
	}

	/*
	 * No initialization (here) of mi_vcomm!
	 */
	vfsp->mnt_data = mi;
	vfs_getnewfsid (vfsp);
	mi->mi_vfsp = vfsp;
	mi->mi_started = 0;			/* XXX See coda_root() */

	/*
	 * Make a root vnode to placate the Vnode interface, but don't
	 * actually make the CODA_ROOT call to venus until the first call to
	 * coda_root in case a server is down while venus is starting.
	 */
	cp = make_coda_node(&rootfid, vfsp, VDIR);
	rootvp = CTOV(cp);
	rootvp->v_vflag |= VV_ROOT;
	cp = make_coda_node(&ctlfid, vfsp, VREG);
	coda_ctlvp = CTOV(cp);

	/*
	 * Add vfs and rootvp to chain of vfs hanging off mntinfo.
	 */
	mi->mi_vfsp = vfsp;
	mi->mi_rootvp = rootvp;
	vfs_mountedfrom(vfsp, from);

	/*
	 * Error is currently guaranteed to be zero, but in case some code
	 * changes...
	 */
	CODADEBUG(1, myprintf(("coda_mount returned %d\n", error)););
	if (error)
		MARK_INT_FAIL(CODA_MOUNT_STATS);
	else
		MARK_INT_SAT(CODA_MOUNT_STATS);
	return (error);
}

int
coda_unmount(struct mount *vfsp, int mntflags, struct thread *td)
{
	struct coda_mntinfo *mi = vftomi(vfsp);
	int active, error = 0;

	ENTRY;
	MARK_ENTRY(CODA_UMOUNT_STATS);
	if (!CODA_MOUNTED(vfsp)) {
		MARK_INT_FAIL(CODA_UMOUNT_STATS);
		return (EINVAL);
	}
	if (mi->mi_vfsp == vfsp) {
		/*
		 * We found the victim.
		 */
		if (!IS_UNMOUNTING(VTOC(mi->mi_rootvp)))
			return (EBUSY); 	/* Venus is still running */
#ifdef DEBUG
		printf("coda_unmount: ROOT: vp %p, cp %p\n", mi->mi_rootvp,
		    VTOC(mi->mi_rootvp));
#endif
		vrele(mi->mi_rootvp);
		mi->mi_rootvp = NULL;
		vrele(coda_ctlvp);
		coda_ctlvp = NULL;
		active = coda_kill(vfsp, NOT_DOWNCALL);
		error = vflush(mi->mi_vfsp, 0, FORCECLOSE, td);
#ifdef CODA_VERBOSE
		printf("coda_unmount: active = %d, vflush active %d\n",
		    active, error);
#endif
		error = 0;
		/*
		 * I'm going to take this out to allow lookups to go through.
		 * I'm not sure it's important anyway. -- DCS 2/2/94
		 */
		/* vfsp->VFS_DATA = NULL; */

		/*
		 * No more vfsp's to hold onto.
		 */
		mi->mi_vfsp = NULL;

		if (error)
			MARK_INT_FAIL(CODA_UMOUNT_STATS);
		else
			MARK_INT_SAT(CODA_UMOUNT_STATS);
		return (error);
	}
	return (EINVAL);
}

/*
 * Find root of cfs.
 */
int
coda_root(struct mount *vfsp, int flags, struct vnode **vpp,
     struct thread *td)
{
	struct coda_mntinfo *mi = vftomi(vfsp);
	struct vnode **result;
	int error;
	struct proc *p = td->td_proc;
	CodaFid VFid;
	static const CodaFid invalfid = INVAL_FID;

	ENTRY;
	MARK_ENTRY(CODA_ROOT_STATS);
	result = NULL;
	if (vfsp == mi->mi_vfsp) {
		/*
		 * Cache the root across calls.  We only need to pass the
		 * request on to Venus if the root vnode is the dummy we
		 * installed in coda_mount() with all c_fid members zeroed.
		 *
		 * XXX In addition, we assume that the first call to
		 * coda_root() is from vfs_mount() (before the call to
		 * checkdirs()) and return the dummy root node to avoid a
		 * deadlock.  This bug is fixed in the Coda CVS repository
		 * but not in any released versions as of 6 Mar 2003.
		 */
		if (memcmp(&VTOC(mi->mi_rootvp)->c_fid, &invalfid,
		    sizeof(CodaFid)) != 0 || mi->mi_started == 0) {
			/*
			 * Found valid root.
			 */
			*vpp = mi->mi_rootvp;
			mi->mi_started = 1;

			/*
			 * On Mach, this is vref.  On FreeBSD, vref +
			 * vn_lock.
			 */
			vref(*vpp);
			vn_lock(*vpp, LK_EXCLUSIVE | LK_RETRY);
			MARK_INT_SAT(CODA_ROOT_STATS);
			return (0);
		}
	}

	error = venus_root(vftomi(vfsp), td->td_ucred, p, &VFid);
	if (!error) {
		/*
		 * Save the new rootfid in the cnode, and rehash the cnode
		 * into the cnode hash with the new fid key.
		 */
		coda_unsave(VTOC(mi->mi_rootvp));
		VTOC(mi->mi_rootvp)->c_fid = VFid;
		coda_save(VTOC(mi->mi_rootvp));
		*vpp = mi->mi_rootvp;
		vref(*vpp);
		vn_lock(*vpp, LK_EXCLUSIVE | LK_RETRY);
		MARK_INT_SAT(CODA_ROOT_STATS);
	} else if (error == ENODEV || error == EINTR) {
		/*
		 * Gross hack here!
		 *
		 * If Venus fails to respond to the CODA_ROOT call, coda_call
		 * returns ENODEV. Return the uninitialized root vnode to
		 * allow vfs operations such as unmount to continue.  Without
		 * this hack, there is no way to do an unmount if Venus dies
		 * before a successful CODA_ROOT call is done.  All vnode
		 * operations will fail.
		 */
		*vpp = mi->mi_rootvp;
		vref(*vpp);
		vn_lock(*vpp, LK_EXCLUSIVE | LK_RETRY);
		MARK_INT_FAIL(CODA_ROOT_STATS);
		error = 0;
	} else {
		CODADEBUG(CODA_ROOT, myprintf(("error %d in CODA_ROOT\n",
		    error)););
		MARK_INT_FAIL(CODA_ROOT_STATS);
	}
	return (error);
}

/*
 * Get filesystem statistics.
 */
int
coda_statfs(struct mount *vfsp, struct statfs *sbp, struct thread *td)
{

	ENTRY;
	MARK_ENTRY(CODA_STATFS_STATS);
	if (!CODA_MOUNTED(vfsp)) {
		MARK_INT_FAIL(CODA_STATFS_STATS);
		return (EINVAL);
	}

	/*
	 * XXX - what to do about f_flags, others? --bnoble
	 *
	 * We just make up free space counts that are sufficiently large.
	 */
	sbp->f_flags = 0;
	sbp->f_bsize = 8192; /* XXX */
	sbp->f_iosize = 8192; /* XXX */
#define	CODA_SFS_SIZ	0x8AB75D
	sbp->f_blocks = CODA_SFS_SIZ;
	sbp->f_bfree = CODA_SFS_SIZ;
	sbp->f_bavail = CODA_SFS_SIZ;
	sbp->f_files = CODA_SFS_SIZ;
	sbp->f_ffree = CODA_SFS_SIZ;
	MARK_INT_SAT(CODA_STATFS_STATS);
	return (0);
}

/*
 * Flush any pending I/O.
 */
int
coda_sync(struct mount *vfsp, int waitfor, struct thread *td)
{

	ENTRY;
	MARK_ENTRY(CODA_SYNC_STATS);
	MARK_INT_SAT(CODA_SYNC_STATS);
	return (0);
}

/*
 * fhtovp is now what vget used to be in 4.3-derived systems.  For some silly
 * reason, vget is now keyed by a 32 bit ino_t, rather than a type-specific
 * fid.
 *
 * XXX: coda_fhtovp is currently not hooked up, so no NFS export for Coda.
 * We leave it here in the hopes that someone will find it someday and hook
 * it up.  Among other things, it will need some reworking to match the
 * vfs_fhtovp_t prototype.
 */
int
coda_fhtovp(struct mount *vfsp, struct fid *fhp, struct mbuf *nam,
    struct vnode **vpp, int *exflagsp, struct ucred **creadanonp)
{
	struct cfid *cfid = (struct cfid *)fhp;
	struct cnode *cp = NULL;
	int error;
	struct thread *td = curthread; /* XXX -mach */
	struct proc *p = td->td_proc;
	CodaFid VFid;
	int vtype;

	ENTRY;
	MARK_ENTRY(CODA_VGET_STATS);

	/*
	 * Check for vget of control object.
	 */
	if (IS_CTL_FID(&cfid->cfid_fid)) {
		*vpp = coda_ctlvp;
		vref(coda_ctlvp);
		MARK_INT_SAT(CODA_VGET_STATS);
		return (0);
	}
	error = venus_fhtovp(vftomi(vfsp), &cfid->cfid_fid, td->td_ucred, p,
	    &VFid, &vtype);
	if (error) {
		CODADEBUG(CODA_VGET, myprintf(("vget error %d\n",error)););
		*vpp = NULL;
	} else {
		CODADEBUG(CODA_VGET, myprintf(("vget: %s type %d result "
		    "%d\n", coda_f2s(&VFid), vtype, error)););
		cp = make_coda_node(&VFid, vfsp, vtype);
		*vpp = CTOV(cp);
	}
	return (error);
}

struct vfsops coda_vfsops = {
	.vfs_mount =		coda_mount,
	.vfs_root = 		coda_root,
	.vfs_statfs =		coda_statfs,
	.vfs_sync = 		coda_sync,
	.vfs_unmount =		coda_unmount,
};
VFS_SET(coda_vfsops, coda, VFCF_NETWORK);