freebsd-skq/sys/fs/coda/coda_subr.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/coda/coda_subr.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.
 */

/*-
 * NOTES: rvb
 * 1.	Added coda_unmounting to mark all cnodes as being UNMOUNTING.  This
 *	has to be done before dounmount is called.  Because some of the
 *	routines that dounmount calls before coda_unmounted might try to
 *	force flushes to venus.  The vnode pager does this.
 * 2.	coda_unmounting marks all cnodes scanning coda_cache.
 * 3.	cfs_checkunmounting (under DEBUG) checks all cnodes by chasing the
 *	vnodes under the /coda mount point.
 * 4.	coda_cacheprint (under DEBUG) prints names with vnode/cnode address.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/mount.h>

#include <fs/coda/coda.h>
#include <fs/coda/cnode.h>
#include <fs/coda/coda_subr.h>

static int coda_active = 0;
static int coda_reuse = 0;
static int coda_new = 0;

static struct cnode *coda_freelist = NULL;
static struct cnode *coda_cache[CODA_CACHESIZE];

#define	CNODE_NEXT(cp)	((cp)->c_next)

#ifdef CODA_COMPAT_5
#define	coda_hash(fid)	(((fid)->Volume + (fid)->Vnode) & (CODA_CACHESIZE-1))
#define	IS_DIR(cnode)	(cnode.Vnode & 0x1)
#else
#define	coda_hash(fid)	(coda_f2i(fid) & (CODA_CACHESIZE-1))
#define	IS_DIR(cnode)	(cnode.opaque[2] & 0x1)
#endif

/*
 * Allocate a cnode.
 */
struct cnode *
coda_alloc(void)
{
	struct cnode *cp;

	if (coda_freelist != NULL) {
		cp = coda_freelist;
		coda_freelist = CNODE_NEXT(cp);
		coda_reuse++;
	} else {
		CODA_ALLOC(cp, struct cnode *, sizeof(struct cnode));

		/*
		 * FreeBSD vnodes don't have any Pager info in them ('cause
		 * there are no external pagers, duh!).
		 */
#define	VNODE_VM_INFO_INIT(vp)         /* MT */
		VNODE_VM_INFO_INIT(CTOV(cp));
		coda_new++;
	}
	bzero(cp, sizeof (struct cnode));
	return (cp);
}

/*
 * Deallocate a cnode.
 */
void
coda_free(struct cnode *cp)
{

	CNODE_NEXT(cp) = coda_freelist;
	coda_freelist = cp;
}

/*
 * Put a cnode in the hash table.
 */
void
coda_save(struct cnode *cp)
{

	CNODE_NEXT(cp) = coda_cache[coda_hash(&cp->c_fid)];
	coda_cache[coda_hash(&cp->c_fid)] = cp;
}

/*
 * Remove a cnode from the hash table.
 */
void
coda_unsave(struct cnode *cp)
{
	struct cnode *ptr;
	struct cnode *ptrprev = NULL;

	ptr = coda_cache[coda_hash(&cp->c_fid)];
	while (ptr != NULL) {
		if (ptr == cp) {
			if (ptrprev == NULL)
				coda_cache[coda_hash(&cp->c_fid)] =
				    CNODE_NEXT(ptr);
	    		else
				CNODE_NEXT(ptrprev) = CNODE_NEXT(ptr);
			CNODE_NEXT(cp) = (struct cnode *)NULL;
			return;
		}
		ptrprev = ptr;
		ptr = CNODE_NEXT(ptr);
	}
}

/*
 * Lookup a cnode by fid. If the cnode is dying, it is bogus so skip it.
 *
 * NOTE: this allows multiple cnodes with same fid -- dcs 1/25/95
 */
struct cnode *
coda_find(struct CodaFid *fid)
{
	struct cnode *cp;

	cp = coda_cache[coda_hash(fid)];
	while (cp) {
		if (coda_fid_eq(&(cp->c_fid), fid) && (!IS_UNMOUNTING(cp))) {
			coda_active++;
			return (cp);
		}
		cp = CNODE_NEXT(cp);
	}
	return (NULL);
}

/*
 * Clear all cached access control decisions from Coda.
 */
static void
coda_acccache_purge(struct mount *mnt)
{
	struct cnode *cp;
	int hash;

	for (hash = 0; hash < CODA_CACHESIZE; hash++) {
		for (cp = coda_cache[hash]; cp != NULL;
		    cp = CNODE_NEXT(cp)) {
			if (CTOV(cp)->v_mount == mnt && VALID_ACCCACHE(cp)) {
				CODADEBUG(CODA_FLUSH, myprintf(("acccache "
				    "purge fid %s uid %d mode 0x%x\n",
				    coda_f2s(&cp->c_fid), cp->c_cached_uid,
				    (int)cp->c_cached_mode)););
				cp->c_flags &= ~C_ACCCACHE;
			}
		}
	}
}

/*
 * When a user loses their tokens (or other related events), we invalidate
 * any cached access rights in the access cache.  In the Linux version of
 * Coda, we maintain a global epoch and simply bump it to invalidate all
 * cached results generated in the epoch.  For now, we walk all cnodes and
 * manually invalidate just that uid in FreeBSD.
 */
static void
coda_acccache_purgeuser(struct mount *mnt, uid_t uid)
{
	struct cnode *cp;
	int hash;

	for (hash = 0; hash < CODA_CACHESIZE; hash++) {
		for (cp = coda_cache[hash]; cp != NULL;
		    cp = CNODE_NEXT(cp)) {
			if (CTOV(cp)->v_mount == mnt &&
			    VALID_ACCCACHE(cp) && (cp->c_cached_uid == uid)) {
				CODADEBUG(CODA_PURGEUSER, myprintf((
				    "acccache purgeuser fid %s uid %d mode "
				    "0x%x\n", coda_f2s(&cp->c_fid),
				    cp->c_cached_uid, (int)cp->c_cached_mode)););
				cp->c_flags &= ~C_ACCCACHE;
			}
		}
	}
}

/*
 * coda_kill is called as a side effect to vcopen.  To prevent any cnodes
 * left around from an earlier run of a venus or warden from causing problems
 * with the new instance, mark any outstanding cnodes as dying.  Future
 * operations on these cnodes should fail (excepting coda_inactive of
 * course!).  Since multiple venii/wardens can be running, only kill the
 * cnodes for a particular entry in the coda_mnttbl. -- DCS 12/1/94
 *
 * XXX: I don't believe any special behavior is required with respect to the
 * global namecache here, as /coda will have unmounted and hence cache_flush
 * will have run...?
 */
int
coda_kill(struct mount *whoIam, enum dc_status dcstat)
{
	int hash, count = 0;
	struct cnode *cp;

	/*-
	 * Algorithm is as follows:
	 *     Second, flush whatever vnodes we can from the name cache.
	 *
	 *     Finally, step through whatever is left and mark them dying.
	 *        This prevents any operation at all.
	 *
	 * This is slightly overkill, but should work.  Eventually it'd be
	 * nice to only flush those entries from the namecache that reference
	 * a vnode in this vfs.
	 *
	 * XXXRW: Perhaps we no longer need to purge the name cache when
	 * using the VFS name cache, as unmount will do that.
	 */
	cache_purgevfs(whoIam);
	for (hash = 0; hash < CODA_CACHESIZE; hash++) {
		for (cp = coda_cache[hash];cp != NULL;
		    cp = CNODE_NEXT(cp)) {
			if (CTOV(cp)->v_mount == whoIam) {
#ifdef DEBUG
				printf("coda_kill: vp %p, cp %p\n", CTOV(cp),
				    cp);
#endif
				count++;
				CODADEBUG(CODA_FLUSH, myprintf(("Live cnode "
				    "fid %s flags %d count %d\n",
				    coda_f2s(&cp->c_fid), cp->c_flags,
				    vrefcnt(CTOV(cp)))););
			}
		}
	}
	return (count);
}

/*
 * There are two reasons why a cnode may be in use, it may be in the name
 * cache or it may be executing.
 */
void
coda_flush(struct coda_mntinfo *mnt, enum dc_status dcstat)
{
	int hash;
	struct cnode *cp;

	coda_clstat.ncalls++;
	coda_clstat.reqs[CODA_FLUSH]++;

	coda_acccache_purge(mnt->mi_vfsp);
	cache_purgevfs(mnt->mi_vfsp);
	for (hash = 0; hash < CODA_CACHESIZE; hash++) {
		for (cp = coda_cache[hash]; cp != NULL;
		    cp = CNODE_NEXT(cp)) {
			/*
			 * Only files that can be executed need to be flushed
			 * from the VM.
			 *
			 * NOTE: Currently this doesn't do anything, but
			 * perhaps it should?
			 */
			if (!IS_DIR(cp->c_fid))
				coda_vmflush(cp);
		}
	}
}

/*
 * As a debugging measure, print out any cnodes that lived through a name
 * cache flush.
 */
void
coda_testflush(void)
{
	int hash;
	struct cnode *cp;

	for (hash = 0; hash < CODA_CACHESIZE; hash++) {
		for (cp = coda_cache[hash]; cp != NULL;
		    cp = CNODE_NEXT(cp))
			myprintf(("Live cnode fid %s count %d\n",
			    coda_f2s(&cp->c_fid), CTOV(cp)->v_usecount));
	}
}

/*
 * First, step through all cnodes and mark them unmounting.  FreeBSD kernels
 * may try to fsync them now that venus is dead, which would be a bad thing.
 */
void
coda_unmounting(struct mount *whoIam)
{
	int hash;
	struct cnode *cp;

	for (hash = 0; hash < CODA_CACHESIZE; hash++) {
		for (cp = coda_cache[hash]; cp != NULL;
		    cp = CNODE_NEXT(cp)) {
			if (CTOV(cp)->v_mount == whoIam) {
				if (cp->c_flags & (C_LOCKED|C_WANTED)) {
					printf("coda_unmounting: Unlocking "
					    "%p\n", cp);
					cp->c_flags &= ~(C_LOCKED|C_WANTED);
					wakeup((caddr_t) cp);
				}
				cp->c_flags |= C_UNMOUNTING;
			}
		}
	}
}

#ifdef DEBUG
void
coda_checkunmounting(struct mount *mp)
{
	struct vnode *vp, *nvp;
	struct cnode *cp;
	int count = 0, bad = 0;

	MNT_VNODE_FOREACH_ALL(vp, mp, nvp) {
		cp = VTOC(vp);
		count++;
		if (!(cp->c_flags & C_UNMOUNTING)) {
			bad++;
			printf("vp %p, cp %p missed\n", vp, cp);
			cp->c_flags |= C_UNMOUNTING;
		}
		VI_UNLOCK(vp);
	}
}

void
coda_cacheprint(struct mount *whoIam)
{
	int hash;
	struct cnode *cp;
	int count = 0;

	printf("coda_cacheprint: coda_ctlvp %p, cp %p", coda_ctlvp,
	    VTOC(coda_ctlvp));

#if 0
	coda_nc_name(VTOC(coda_ctlvp));
#endif
	printf("\n");
	for (hash = 0; hash < CODA_CACHESIZE; hash++) {
		for (cp = coda_cache[hash]; cp != NULL;
		    cp = CNODE_NEXT(cp)) {
			if (CTOV(cp)->v_mount == whoIam) {
				printf("coda_cacheprint: vp %p, cp %p",
				    CTOV(cp), cp);
#if 0
				coda_nc_name(cp);
#endif
				printf("\n");
				count++;
			}
		}
	}
	printf("coda_cacheprint: count %d\n", count);
}
#endif

/*-
 * There are 6 cases where invalidations occur.  The semantics of each is
 * listed here:
 *
 * CODA_FLUSH     -- Flush all entries from the name cache and the cnode
 *                   cache.
 *
 * CODA_PURGEUSER -- Flush all entries from the name cache for a specific
 *                   user.   This call is a result of token expiration.
 *
 * The next two are the result of callbacks on a file or directory:
 *
 * CODA_ZAPDIR    -- Flush the attributes for the dir from its cnode.  Zap
 *                   all children of this directory from the namecache.
 *
 * CODA_ZAPFILE   -- Flush the attributes for a file.
 *
 * The fifth is a result of Venus detecting an inconsistent file:
 *
 * CODA_PURGEFID  -- Flush the attribute for the file; if it is a dir (odd
 *                   vnode), purge its children from the namecache; remove
 *                   the file from the namecache.
 *
 * The sixth allows Venus to replace local fids with global ones during
 * reintegration.
 *
 * CODA_REPLACE   -- Replace one CodaFid with another throughout the name
 *                   cache.
 */
int
handleDownCall(struct coda_mntinfo *mnt, int opcode, union outputArgs *out)
{
	int error;

	/*
	 * Handle invalidate requests.
	 */
	switch (opcode) {
	case CODA_FLUSH: {
		coda_flush(mnt, IS_DOWNCALL);

		/* Print any remaining cnodes. */
		CODADEBUG(CODA_FLUSH, coda_testflush(););
		return (0);
	}

	case CODA_PURGEUSER: {
		coda_clstat.ncalls++;
		coda_clstat.reqs[CODA_PURGEUSER]++;

		/* XXX - need to prevent fsync's. */

		/*
		 * Purge any access cache entries for the uid.
		 */
#ifdef CODA_COMPAT_5
	  	coda_acccache_purgeuser(mnt->mi_vfsp,
		    out->coda_purgeuser.cred.cr_uid);
#else
		coda_acccache_purgeuser(mnt->mi_vfsp,
		    out->coda_purgeuser.uid);
#endif
		return (0);
	}

	case CODA_ZAPFILE: {
		struct cnode *cp;

		error = 0;
		coda_clstat.ncalls++;
		coda_clstat.reqs[CODA_ZAPFILE]++;
		cp = coda_find(&out->coda_zapfile.Fid);
		if (cp != NULL) {
			vref(CTOV(cp));
			cache_purge(CTOV(cp));
			cp->c_flags &= ~(C_VATTR | C_ACCCACHE);
			ASSERT_VOP_LOCKED(CTOV(cp), "coda HandleDownCall");
			if (VOP_IS_TEXT(CTOV(cp)))
				error = coda_vmflush(cp);
			CODADEBUG(CODA_ZAPFILE,
			myprintf(("zapfile: fid = %s, refcnt = %d, error = "
			    "%d\n", coda_f2s(&cp->c_fid),
			    CTOV(cp)->v_usecount - 1, error)););
			if (vrefcnt(CTOV(cp)) == 1)
				cp->c_flags |= C_PURGING;
			vrele(CTOV(cp));
		}
		return (error);
      }

      case CODA_ZAPDIR: {
		struct cnode *cp;

		coda_clstat.ncalls++;
		coda_clstat.reqs[CODA_ZAPDIR]++;
		cp = coda_find(&out->coda_zapdir.Fid);
		if (cp != NULL) {
			vref(CTOV(cp));
			cache_purge(CTOV(cp));
			cp->c_flags &= ~(C_VATTR | C_ACCCACHE);
			CODADEBUG(CODA_ZAPDIR, myprintf(("zapdir: fid = %s, "
			    "refcnt = %d\n", coda_f2s(&cp->c_fid),
			    CTOV(cp)->v_usecount - 1)););
			if (vrefcnt(CTOV(cp)) == 1)
				cp->c_flags |= C_PURGING;
			vrele(CTOV(cp));
		}
		return (0);
      }

      case CODA_PURGEFID: {
		struct cnode *cp;

		error = 0;
		coda_clstat.ncalls++;
		coda_clstat.reqs[CODA_PURGEFID]++;
		cp = coda_find(&out->coda_purgefid.Fid);
		if (cp != NULL) {
			vref(CTOV(cp));
			cache_purge(CTOV(cp));
			cp->c_flags &= ~(C_VATTR | C_ACCCACHE);
			ASSERT_VOP_LOCKED(CTOV(cp), "coda HandleDownCall");
			if (!(IS_DIR(out->coda_purgefid.Fid))
			    && VOP_IS_TEXT(CTOV(cp)))
				error = coda_vmflush(cp);
			CODADEBUG(CODA_PURGEFID, myprintf(("purgefid: fid "
			    "= %s, refcnt = %d, error = %d\n",
			    coda_f2s(&cp->c_fid),
			    CTOV(cp)->v_usecount - 1, error)););
			if (vrefcnt(CTOV(cp)) == 1)
				cp->c_flags |= C_PURGING;
			vrele(CTOV(cp));
		}
		return (error);
	}

	case CODA_REPLACE: {
		struct cnode *cp = NULL;

		coda_clstat.ncalls++;
		coda_clstat.reqs[CODA_REPLACE]++;
		cp = coda_find(&out->coda_replace.OldFid);
		if (cp != NULL) {
			/*
			 * Remove the cnode from the hash table, replace the
			 * fid, and reinsert.  Clear the attribute cache as
			 * the "inode number" may have changed (it's just a
			 * hash of the fid, and the fid is changing).
			 */
			vref(CTOV(cp));
			coda_unsave(cp);
			cp->c_fid = out->coda_replace.NewFid;
			cp->c_flags &= ~C_VATTR;
			coda_save(cp);
			CODADEBUG(CODA_REPLACE, myprintf(("replace: oldfid "
			    "= %s, newfid = %s, cp = %p\n",
			    coda_f2s(&out->coda_replace.OldFid),
			    coda_f2s(&cp->c_fid), cp)););
			vrele(CTOV(cp));
	  	}
		return (0);
	}
	default:
		myprintf(("handleDownCall: unknown opcode %d\n", opcode));
		return (EINVAL);
	}
}

int
coda_vmflush(struct cnode *cp)
{

	return (0);
}

/*
 * Kernel-internal debugging switches.
 */
void
coda_debugon(void)
{

	codadebug = -1;
	coda_vnop_print_entry = 1;
	coda_psdev_print_entry = 1;
	coda_vfsop_print_entry = 1;
}

void
coda_debugoff(void)
{

	codadebug = 0;
	coda_vnop_print_entry = 0;
	coda_psdev_print_entry = 0;
	coda_vfsop_print_entry = 0;
}

/*-
 * Utilities used by both client and server
 * Standard levels:
 * 0) no debugging
 * 1) hard failures
 * 2) soft failures
 * 3) current test software
 * 4) main procedure entry points
 * 5) main procedure exit points
 * 6) utility procedure entry points
 * 7) utility procedure exit points
 * 8) obscure procedure entry points
 * 9) obscure procedure exit points
 * 10) random stuff
 * 11) all <= 1
 * 12) all <= 2
 * 13) all <= 3
 * ...
 */