upcall.c

ARM 嵌入式 系统 设计与实例开发 实验教材 二源码

        CDEBUG(D_INODE, " result %d\n",error);
	CODA_FREE(inp, insize);
        return error;
}

int venus_fsync(struct super_block *sb, struct ViceFid *fid)
{
        union inputArgs *inp;
        union outputArgs *outp; 
	int insize, outsize, error;
	
	insize=SIZE(fsync);
	UPARG(CODA_FSYNC);

        inp->coda_fsync.VFid = *fid;
        error = coda_upcall(coda_sbp(sb), sizeof(union inputArgs), 
                            &outsize, inp);

	CODA_FREE(inp, insize);
	return error;
}

int venus_access(struct super_block *sb, struct ViceFid *fid, int mask)
{
        union inputArgs *inp;
        union outputArgs *outp; 
	int insize, outsize, error;

	insize = SIZE(access);
	UPARG(CODA_ACCESS);

        inp->coda_access.VFid = *fid;
        inp->coda_access.flags = mask;

	error = coda_upcall(coda_sbp(sb), insize, &outsize, inp);

	CODA_FREE(inp, insize);
	return error;
}


int venus_pioctl(struct super_block *sb, struct ViceFid *fid,
		 unsigned int cmd, struct PioctlData *data)
{
        union inputArgs *inp;
        union outputArgs *outp;  
	int insize, outsize, error;
	int iocsize;

	insize = VC_MAXMSGSIZE;
	UPARG(CODA_IOCTL);

        /* build packet for Venus */
        if (data->vi.in_size > VC_MAXDATASIZE) {
		error = -EINVAL;
		goto exit;
        }

        inp->coda_ioctl.VFid = *fid;
    
        /* the cmd field was mutated by increasing its size field to
         * reflect the path and follow args. We need to subtract that
         * out before sending the command to Venus.  */
        inp->coda_ioctl.cmd = (cmd & ~(PIOCPARM_MASK << 16));	
        iocsize = ((cmd >> 16) & PIOCPARM_MASK) - sizeof(char *) - sizeof(int);
        inp->coda_ioctl.cmd |= (iocsize & PIOCPARM_MASK) <<	16;	
    
        /* in->coda_ioctl.rwflag = flag; */
        inp->coda_ioctl.len = data->vi.in_size;
        inp->coda_ioctl.data = (char *)(INSIZE(ioctl));
     
        /* get the data out of user space */
        if ( copy_from_user((char*)inp + (long)inp->coda_ioctl.data,
			    data->vi.in, data->vi.in_size) ) {
		error = -EINVAL;
	        goto exit;
	}

        error = coda_upcall(coda_sbp(sb), SIZE(ioctl) + data->vi.in_size,
                            &outsize, inp);
        
        if (error) {
	        printk("coda_pioctl: Venus returns: %d for %s\n", 
		       error, coda_f2s(fid));
		goto exit; 
	}
        
	/* Copy out the OUT buffer. */
        if (outp->coda_ioctl.len > data->vi.out_size) {
                CDEBUG(D_FILE, "return len %d <= request len %d\n",
                      outp->coda_ioctl.len, 
                      data->vi.out_size);
		error = -EINVAL;
        } else {
		error = verify_area(VERIFY_WRITE, data->vi.out, 
                                    data->vi.out_size);
		if ( error ) goto exit;

		if (copy_to_user(data->vi.out, 
				 (char *)outp + (long)outp->coda_ioctl.data, 
				 data->vi.out_size)) {
			error = -EINVAL;
			goto exit;
		}
        }

 exit:
	CODA_FREE(inp, insize);
	return error;
}

int venus_statfs(struct super_block *sb, struct statfs *sfs) 
{ 
        union inputArgs *inp;
        union outputArgs *outp;
        int insize, outsize, error;
        
	insize = max_t(unsigned int, INSIZE(statfs), OUTSIZE(statfs));
	UPARG(CODA_STATFS);

        error = coda_upcall(coda_sbp(sb), insize, &outsize, inp);
	
        if (!error) {
		sfs->f_blocks = outp->coda_statfs.stat.f_blocks;
		sfs->f_bfree  = outp->coda_statfs.stat.f_bfree;
		sfs->f_bavail = outp->coda_statfs.stat.f_bavail;
		sfs->f_files  = outp->coda_statfs.stat.f_files;
		sfs->f_ffree  = outp->coda_statfs.stat.f_ffree;
	} else {
		printk("coda_statfs: Venus returns: %d\n", error);
	}

        CDEBUG(D_INODE, " result %d\n",error);
        CODA_FREE(inp, insize);
        return error;
}

/*
 * coda_upcall and coda_downcall routines.
 * 
 */

static inline unsigned long coda_waitfor_upcall(struct upc_req *vmp,
						struct venus_comm *vcommp)
{
	DECLARE_WAITQUEUE(wait, current);
 	struct timeval begin = { 0, 0 }, end = { 0, 0 };

	vmp->uc_posttime = jiffies;

	if (coda_upcall_timestamping)
		do_gettimeofday(&begin);

	add_wait_queue(&vmp->uc_sleep, &wait);
	for (;;) {
		if ( !coda_hard && vmp->uc_opcode != CODA_CLOSE ) 
			set_current_state(TASK_INTERRUPTIBLE);
		else
			set_current_state(TASK_UNINTERRUPTIBLE);

                /* venus died */
                if ( !vcommp->vc_inuse )
                        break;

		/* got a reply */
		if ( vmp->uc_flags & ( REQ_WRITE | REQ_ABORT ) )
			break;

		if ( !coda_hard && vmp->uc_opcode != CODA_CLOSE && signal_pending(current) ) {
			/* if this process really wants to die, let it go */
			if ( sigismember(&(current->pending.signal), SIGKILL) ||
			     sigismember(&(current->pending.signal), SIGINT) )
				break;
			/* signal is present: after timeout always return 
			   really smart idea, probably useless ... */
			if ( jiffies - vmp->uc_posttime > coda_timeout * HZ )
				break; 
		}
		schedule();
	}
	remove_wait_queue(&vmp->uc_sleep, &wait);
	set_current_state(TASK_RUNNING);

	if (coda_upcall_timestamping && begin.tv_sec != 0) {
		do_gettimeofday(&end);

		if (end.tv_usec < begin.tv_usec) {
			end.tv_usec += 1000000; end.tv_sec--;
		}
		end.tv_sec  -= begin.tv_sec;
		end.tv_usec -= begin.tv_usec;
	}

	CDEBUG(D_SPECIAL, "begin: %ld.%06ld, elapsed: %ld.%06ld\n",
		begin.tv_sec, (unsigned long)begin.tv_usec,
		end.tv_sec, (unsigned long)end.tv_usec);

	return 	((end.tv_sec * 1000000) + end.tv_usec);
}


/* 
 * coda_upcall will return an error in the case of 
 * failed communication with Venus _or_ will peek at Venus
 * reply and return Venus' error.
 *
 * As venus has 2 types of errors, normal errors (positive) and internal
 * errors (negative), normal errors are negated, while internal errors
 * are all mapped to -EINTR, while showing a nice warning message. (jh)
 * 
 */
static int coda_upcall(struct coda_sb_info *sbi, 
		int inSize, int *outSize, 
		union inputArgs *buffer) 
{
	unsigned long runtime; 
	struct venus_comm *vcommp;
	union outputArgs *out;
	struct upc_req *req;
	int error = 0;

	vcommp = sbi->sbi_vcomm;
	if ( !vcommp->vc_inuse ) {
		printk("No pseudo device in upcall comms at %p\n", vcommp);
                return -ENXIO;
	}

	/* Format the request message. */
	req = upc_alloc();
	if (!req) {
		printk("Failed to allocate upc_req structure\n");
		return -ENOMEM;
	}
	req->uc_data = (void *)buffer;
	req->uc_flags = 0;
	req->uc_inSize = inSize;
	req->uc_outSize = *outSize ? *outSize : inSize;
	req->uc_opcode = ((union inputArgs *)buffer)->ih.opcode;
	req->uc_unique = ++vcommp->vc_seq;
	init_waitqueue_head(&req->uc_sleep);
	
	/* Fill in the common input args. */
	((union inputArgs *)buffer)->ih.unique = req->uc_unique;

	/* Append msg to pending queue and poke Venus. */
	list_add(&(req->uc_chain), vcommp->vc_pending.prev);
        
	CDEBUG(D_UPCALL, 
	       "Proc %d wake Venus for(opc,uniq) =(%d,%d) msg at %p.zzz.\n",
	       current->pid, req->uc_opcode, req->uc_unique, req);

	wake_up_interruptible(&vcommp->vc_waitq);
	/* We can be interrupted while we wait for Venus to process
	 * our request.  If the interrupt occurs before Venus has read
	 * the request, we dequeue and return. If it occurs after the
	 * read but before the reply, we dequeue, send a signal
	 * message, and return. If it occurs after the reply we ignore
	 * it. In no case do we want to restart the syscall.  If it
	 * was interrupted by a venus shutdown (psdev_close), return
	 * ENODEV.  */

	/* Go to sleep.  Wake up on signals only after the timeout. */
	runtime = coda_waitfor_upcall(req, vcommp);
	coda_upcall_stats(((union inputArgs *)buffer)->ih.opcode, runtime);

	CDEBUG(D_TIMING, "opc: %d time: %ld uniq: %d size: %d\n",
	       req->uc_opcode, jiffies - req->uc_posttime, 
	       req->uc_unique, req->uc_outSize);
	CDEBUG(D_UPCALL, 
	       "..process %d woken up by Venus for req at %p, data at %p\n", 
	       current->pid, req, req->uc_data);
	if (vcommp->vc_inuse) {      /* i.e. Venus is still alive */
	    /* Op went through, interrupt or not... */
	    if (req->uc_flags & REQ_WRITE) {
		out = (union outputArgs *)req->uc_data;
		/* here we map positive Venus errors to kernel errors */
		error = -out->oh.result;
		CDEBUG(D_UPCALL, 
		       "upcall: (u,o,r) (%ld, %ld, %ld) out at %p\n", 
		       out->oh.unique, out->oh.opcode, out->oh.result, out);
		*outSize = req->uc_outSize;
		goto exit;
	    }
	    if ( !(req->uc_flags & REQ_READ) && signal_pending(current)) { 
		/* Interrupted before venus read it. */
		CDEBUG(D_UPCALL, 
		       "Interrupted before read:(op,un) (%d.%d), flags = %x\n",
		       req->uc_opcode, req->uc_unique, req->uc_flags);
		list_del(&(req->uc_chain));
		/* perhaps the best way to convince the app to
		   give up? */
		error = -EINTR;
		goto exit;
	    } 
	    if ( (req->uc_flags & REQ_READ) && signal_pending(current) ) {
		    /* interrupted after Venus did its read, send signal */
		    union inputArgs *sig_inputArgs;
		    struct upc_req *sig_req;
		    
		    CDEBUG(D_UPCALL, 
			   "Sending Venus a signal: op = %d.%d, flags = %x\n",
			   req->uc_opcode, req->uc_unique, req->uc_flags);
		    
		    list_del(&(req->uc_chain));
		    error = -ENOMEM;
		    sig_req = upc_alloc();
		    if (!sig_req) goto exit;

		    CODA_ALLOC((sig_req->uc_data), char *, sizeof(struct coda_in_hdr));
		    if (!sig_req->uc_data) {
			upc_free(sig_req);
			goto exit;
		    }
		    
		    error = -EINTR;
		    sig_inputArgs = (union inputArgs *)sig_req->uc_data;
		    sig_inputArgs->ih.opcode = CODA_SIGNAL;
		    sig_inputArgs->ih.unique = req->uc_unique;
		    
		    sig_req->uc_flags = REQ_ASYNC;
		    sig_req->uc_opcode = sig_inputArgs->ih.opcode;
		    sig_req->uc_unique = sig_inputArgs->ih.unique;
		    sig_req->uc_inSize = sizeof(struct coda_in_hdr);
		    sig_req->uc_outSize = sizeof(struct coda_in_hdr);
		    CDEBUG(D_UPCALL, 
			   "coda_upcall: enqueing signal msg (%d, %d)\n",
			   sig_req->uc_opcode, sig_req->uc_unique);
		    
		    /* insert at head of queue! */
		    list_add(&(sig_req->uc_chain), &vcommp->vc_pending);
		    wake_up_interruptible(&vcommp->vc_waitq);
	    } else {
		    printk("Coda: Strange interruption..\n");
		    error = -EINTR;
	    }
	} else {	/* If venus died i.e. !VC_OPEN(vcommp) */
	        printk("coda_upcall: Venus dead on (op,un) (%d.%d) flags %d\n",
		       req->uc_opcode, req->uc_unique, req->uc_flags);
		error = -ENODEV;
	}

 exit:
	upc_free(req);
	if (error) 
	        badclstats();
	return error;
}

/*  
    The statements below are part of the Coda opportunistic
    programming -- taken from the Mach/BSD kernel code for Coda. 
    You don't get correct semantics by stating what needs to be
    done without guaranteeing the invariants needed for it to happen.
    When will be have time to find out what exactly is going on?  (pjb)
*/


/* 
 * There are 7 cases where cache 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 arise as the result of callbacks on a file or directory.
 * CODA_ZAPFILE   -- flush the cached attributes for a file.

 * CODA_ZAPDIR    -- flush the attributes for the dir and
 *                  force a new lookup for all the children
                    of this dir.

 *
 * The next is a result of Venus detecting an inconsistent file.
 * CODA_PURGEFID  -- flush the attribute for the file
 *                  purge it and its children from the dcache
 *
 * The last  allows Venus to replace local fids with global ones
 * during reintegration.
 *
 * CODA_REPLACE -- replace one ViceFid with another throughout the name cache */

int coda_downcall(int opcode, union outputArgs * out, struct super_block *sb)
{
	/* Handle invalidation requests. */
          if ( !sb || !sb->s_root || !sb->s_root->d_inode) { 
	          CDEBUG(D_DOWNCALL, "coda_downcall: opcode %d, no sb!\n", opcode);
		  return 0; 
	  }

	  switch (opcode) {

	  case CODA_FLUSH : {
	           clstats(CODA_FLUSH);
		   CDEBUG(D_DOWNCALL, "CODA_FLUSH\n");
		   coda_cache_clear_all(sb, NULL);
		   shrink_dcache_sb(sb);
		   coda_flag_inode(sb->s_root->d_inode, C_FLUSH);
		   return(0);
	  }

	  case CODA_PURGEUSER : {
	           struct coda_cred *cred = &out->coda_purgeuser.cred;
		   CDEBUG(D_DOWNCALL, "CODA_PURGEUSER\n");
		   if ( !cred ) {
		           printk("PURGEUSER: null cred!\n");
			   return 0;
		   }
		   clstats(CODA_PURGEUSER);
		   coda_cache_clear_all(sb, cred);
		   return(0);
	  }

	  case CODA_ZAPDIR : {
	          struct inode *inode;
		  ViceFid *fid = &out->coda_zapdir.CodaFid;
		  CDEBUG(D_DOWNCALL, "zapdir: fid = %s...\n", coda_f2s(fid));
		  clstats(CODA_ZAPDIR);

		  inode = coda_fid_to_inode(fid, sb);
		  if (inode) {
			  CDEBUG(D_DOWNCALL, "zapdir: inode = %ld children flagged\n", 
				 inode->i_ino);
			  coda_flag_inode_children(inode, C_PURGE);
			  CDEBUG(D_DOWNCALL, "zapdir: inode = %ld cache cleared\n", inode->i_ino);
	                  coda_flag_inode(inode, C_VATTR);
			  iput(inode);
		  } else 
			  CDEBUG(D_DOWNCALL, "zapdir: no inode\n");
		  
		  return(0);
	  }

	  case CODA_ZAPFILE : {
	          struct inode *inode;
		  struct ViceFid *fid = &out->coda_zapfile.CodaFid;
		  clstats(CODA_ZAPFILE);
		  CDEBUG(D_DOWNCALL, "zapfile: fid = %s\n", coda_f2s(fid));
		  inode = coda_fid_to_inode(fid, sb);
		  if ( inode ) {
			  CDEBUG(D_DOWNCALL, "zapfile: inode = %ld\n",
				 inode->i_ino);
	                  coda_flag_inode(inode, C_VATTR);
			  iput(inode);
		  } else 
			  CDEBUG(D_DOWNCALL, "zapfile: no inode\n");
		  return 0;
	  }

	  case CODA_PURGEFID : {
	          struct inode *inode;
		  ViceFid *fid = &out->coda_purgefid.CodaFid;
		  CDEBUG(D_DOWNCALL, "purgefid: fid = %s\n", coda_f2s(fid));
		  clstats(CODA_PURGEFID);
		  inode = coda_fid_to_inode(fid, sb);
		  if ( inode ) { 
			CDEBUG(D_DOWNCALL, "purgefid: inode = %ld\n",
			       inode->i_ino);
			coda_flag_inode_children(inode, C_PURGE);

			/* catch the dentries later if some are still busy */
			coda_flag_inode(inode, C_PURGE);
			d_prune_aliases(inode);

			iput(inode);
		  } else 
			CDEBUG(D_DOWNCALL, "purgefid: no inode\n");
		  return 0;
	  }

	  case CODA_REPLACE : {
	          struct inode *inode;
		  ViceFid *oldfid = &out->coda_replace.OldFid;
		  ViceFid *newfid = &out->coda_replace.NewFid;
		  clstats(CODA_REPLACE);
		  CDEBUG(D_DOWNCALL, "CODA_REPLACE\n");
		  inode = coda_fid_to_inode(oldfid, sb);
		  if ( inode ) { 
			  CDEBUG(D_DOWNCALL, "replacefid: inode = %ld\n",
				 inode->i_ino);
			  coda_replace_fid(inode, oldfid, newfid);
			  iput(inode);
		  }else 
			  CDEBUG(D_DOWNCALL, "purgefid: no inode\n");
		  
		  return 0;
	  }
	  }
	  return 0;
}