Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 961 insertions, 0 deletions

diff --git a/fs/coda/upcall.c b/fs/coda/upcall.c
new file mode 100644
index 0000000000..cd6a3721f6
--- /dev/null
+++ b/fs/coda/upcall.c
@@ -0,0 +1,961 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Mostly platform independent upcall operations to Venus:
+ *  -- upcalls
+ *  -- upcall routines
+ *
+ * Linux 2.0 version
+ * Copyright (C) 1996 Peter J. Braam <braam@maths.ox.ac.uk>, 
+ * Michael Callahan <callahan@maths.ox.ac.uk> 
+ * 
+ * Redone for Linux 2.1
+ * Copyright (C) 1997 Carnegie Mellon University
+ *
+ * Carnegie Mellon University encourages users of this code to contribute
+ * improvements to the Coda project. Contact Peter Braam <coda@cs.cmu.edu>.
+ */
+
+#include <linux/signal.h>
+#include <linux/sched/signal.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/stat.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/uaccess.h>
+#include <linux/vmalloc.h>
+#include <linux/vfs.h>
+
+#include <linux/coda.h>
+#include "coda_psdev.h"
+#include "coda_linux.h"
+#include "coda_cache.h"
+
+#include "coda_int.h"
+
+static int coda_upcall(struct venus_comm *vc, int inSize, int *outSize,
+		       union inputArgs *buffer);
+
+static void *alloc_upcall(int opcode, int size)
+{
+	union inputArgs *inp;
+
+	inp = kvzalloc(size, GFP_KERNEL);
+        if (!inp)
+		return ERR_PTR(-ENOMEM);
+
+        inp->ih.opcode = opcode;
+	inp->ih.pid = task_pid_nr_ns(current, &init_pid_ns);
+	inp->ih.pgid = task_pgrp_nr_ns(current, &init_pid_ns);
+	inp->ih.uid = from_kuid(&init_user_ns, current_fsuid());
+
+	return (void*)inp;
+}
+
+#define UPARG(op)\
+do {\
+	inp = (union inputArgs *)alloc_upcall(op, insize); \
+        if (IS_ERR(inp)) { return PTR_ERR(inp); }\
+        outp = (union outputArgs *)(inp); \
+        outsize = insize; \
+} while (0)
+
+#define INSIZE(tag) sizeof(struct coda_ ## tag ## _in)
+#define OUTSIZE(tag) sizeof(struct coda_ ## tag ## _out)
+#define SIZE(tag)  max_t(unsigned int, INSIZE(tag), OUTSIZE(tag))
+
+
+/* the upcalls */
+int venus_rootfid(struct super_block *sb, struct CodaFid *fidp)
+{
+        union inputArgs *inp;
+        union outputArgs *outp;
+        int insize, outsize, error;
+
+        insize = SIZE(root);
+        UPARG(CODA_ROOT);
+
+	error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
+	if (!error)
+		*fidp = outp->coda_root.VFid;
+
+	kvfree(inp);
+	return error;
+}
+
+int venus_getattr(struct super_block *sb, struct CodaFid *fid, 
+		     struct coda_vattr *attr) 
+{
+        union inputArgs *inp;
+        union outputArgs *outp;
+        int insize, outsize, error;
+
+        insize = SIZE(getattr); 
+	UPARG(CODA_GETATTR);
+        inp->coda_getattr.VFid = *fid;
+
+	error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
+	if (!error)
+		*attr = outp->coda_getattr.attr;
+
+	kvfree(inp);
+        return error;
+}
+
+int venus_setattr(struct super_block *sb, struct CodaFid *fid, 
+		  struct coda_vattr *vattr)
+{
+        union inputArgs *inp;
+        union outputArgs *outp;
+        int insize, outsize, error;
+	
+	insize = SIZE(setattr);
+	UPARG(CODA_SETATTR);
+
+        inp->coda_setattr.VFid = *fid;
+	inp->coda_setattr.attr = *vattr;
+
+	error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
+
+	kvfree(inp);
+        return error;
+}
+
+int venus_lookup(struct super_block *sb, struct CodaFid *fid, 
+		    const char *name, int length, int * type, 
+		    struct CodaFid *resfid)
+{
+        union inputArgs *inp;
+        union outputArgs *outp;
+        int insize, outsize, error;
+	int offset;
+
+	offset = INSIZE(lookup);
+        insize = max_t(unsigned int, offset + length +1, OUTSIZE(lookup));
+	UPARG(CODA_LOOKUP);
+
+        inp->coda_lookup.VFid = *fid;
+	inp->coda_lookup.name = offset;
+	inp->coda_lookup.flags = CLU_CASE_SENSITIVE;
+        /* send Venus a null terminated string */
+        memcpy((char *)(inp) + offset, name, length);
+        *((char *)inp + offset + length) = '\0';
+
+	error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
+	if (!error) {
+		*resfid = outp->coda_lookup.VFid;
+		*type = outp->coda_lookup.vtype;
+	}
+
+	kvfree(inp);
+	return error;
+}
+
+int venus_close(struct super_block *sb, struct CodaFid *fid, int flags,
+		kuid_t uid)
+{
+	union inputArgs *inp;
+	union outputArgs *outp;
+	int insize, outsize, error;
+	
+	insize = SIZE(release);
+	UPARG(CODA_CLOSE);
+	
+	inp->ih.uid = from_kuid(&init_user_ns, uid);
+        inp->coda_close.VFid = *fid;
+        inp->coda_close.flags = flags;
+
+	error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
+
+	kvfree(inp);
+        return error;
+}
+
+int venus_open(struct super_block *sb, struct CodaFid *fid,
+		  int flags, struct file **fh)
+{
+        union inputArgs *inp;
+        union outputArgs *outp;
+        int insize, outsize, error;
+       
+	insize = SIZE(open_by_fd);
+	UPARG(CODA_OPEN_BY_FD);
+
+	inp->coda_open_by_fd.VFid = *fid;
+	inp->coda_open_by_fd.flags = flags;
+
+	error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
+	if (!error)
+		*fh = outp->coda_open_by_fd.fh;
+
+	kvfree(inp);
+	return error;
+}	
+
+int venus_mkdir(struct super_block *sb, struct CodaFid *dirfid, 
+		   const char *name, int length, 
+		   struct CodaFid *newfid, struct coda_vattr *attrs)
+{
+        union inputArgs *inp;
+        union outputArgs *outp;
+        int insize, outsize, error;
+        int offset;
+
+	offset = INSIZE(mkdir);
+	insize = max_t(unsigned int, offset + length + 1, OUTSIZE(mkdir));
+	UPARG(CODA_MKDIR);
+
+        inp->coda_mkdir.VFid = *dirfid;
+        inp->coda_mkdir.attr = *attrs;
+	inp->coda_mkdir.name = offset;
+        /* Venus must get null terminated string */
+        memcpy((char *)(inp) + offset, name, length);
+        *((char *)inp + offset + length) = '\0';
+
+	error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
+	if (!error) {
+		*attrs = outp->coda_mkdir.attr;
+		*newfid = outp->coda_mkdir.VFid;
+	}
+
+	kvfree(inp);
+	return error;        
+}
+
+
+int venus_rename(struct super_block *sb, struct CodaFid *old_fid, 
+		 struct CodaFid *new_fid, size_t old_length, 
+		 size_t new_length, const char *old_name, 
+		 const char *new_name)
+{
+	union inputArgs *inp;
+        union outputArgs *outp;
+        int insize, outsize, error; 
+	int offset, s;
+	
+	offset = INSIZE(rename);
+	insize = max_t(unsigned int, offset + new_length + old_length + 8,
+		     OUTSIZE(rename)); 
+ 	UPARG(CODA_RENAME);
+
+        inp->coda_rename.sourceFid = *old_fid;
+        inp->coda_rename.destFid =  *new_fid;
+        inp->coda_rename.srcname = offset;
+
+        /* Venus must receive an null terminated string */
+        s = ( old_length & ~0x3) +4; /* round up to word boundary */
+        memcpy((char *)(inp) + offset, old_name, old_length);
+        *((char *)inp + offset + old_length) = '\0';
+
+        /* another null terminated string for Venus */
+        offset += s;
+        inp->coda_rename.destname = offset;
+        s = ( new_length & ~0x3) +4; /* round up to word boundary */
+        memcpy((char *)(inp) + offset, new_name, new_length);
+        *((char *)inp + offset + new_length) = '\0';
+
+	error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
+
+	kvfree(inp);
+	return error;
+}
+
+int venus_create(struct super_block *sb, struct CodaFid *dirfid, 
+		 const char *name, int length, int excl, int mode,
+		 struct CodaFid *newfid, struct coda_vattr *attrs) 
+{
+        union inputArgs *inp;
+        union outputArgs *outp;
+        int insize, outsize, error;
+        int offset;
+
+        offset = INSIZE(create);
+	insize = max_t(unsigned int, offset + length + 1, OUTSIZE(create));
+	UPARG(CODA_CREATE);
+
+        inp->coda_create.VFid = *dirfid;
+        inp->coda_create.attr.va_mode = mode;
+	inp->coda_create.excl = excl;
+        inp->coda_create.mode = mode;
+        inp->coda_create.name = offset;
+
+        /* Venus must get null terminated string */
+        memcpy((char *)(inp) + offset, name, length);
+        *((char *)inp + offset + length) = '\0';
+
+	error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
+	if (!error) {
+		*attrs = outp->coda_create.attr;
+		*newfid = outp->coda_create.VFid;
+	}
+
+	kvfree(inp);
+	return error;        
+}
+
+int venus_rmdir(struct super_block *sb, struct CodaFid *dirfid, 
+		    const char *name, int length)
+{
+        union inputArgs *inp;
+        union outputArgs *outp;
+        int insize, outsize, error;
+        int offset;
+
+        offset = INSIZE(rmdir);
+	insize = max_t(unsigned int, offset + length + 1, OUTSIZE(rmdir));
+	UPARG(CODA_RMDIR);
+
+        inp->coda_rmdir.VFid = *dirfid;
+        inp->coda_rmdir.name = offset;
+        memcpy((char *)(inp) + offset, name, length);
+	*((char *)inp + offset + length) = '\0';
+
+	error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
+
+	kvfree(inp);
+	return error;
+}
+
+int venus_remove(struct super_block *sb, struct CodaFid *dirfid, 
+		    const char *name, int length)
+{
+        union inputArgs *inp;
+        union outputArgs *outp;
+        int error=0, insize, outsize, offset;
+
+        offset = INSIZE(remove);
+	insize = max_t(unsigned int, offset + length + 1, OUTSIZE(remove));
+	UPARG(CODA_REMOVE);
+
+        inp->coda_remove.VFid = *dirfid;
+        inp->coda_remove.name = offset;
+        memcpy((char *)(inp) + offset, name, length);
+	*((char *)inp + offset + length) = '\0';
+
+	error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
+
+	kvfree(inp);
+	return error;
+}
+
+int venus_readlink(struct super_block *sb, struct CodaFid *fid, 
+		      char *buffer, int *length)
+{ 
+        union inputArgs *inp;
+        union outputArgs *outp;
+        int insize, outsize, error;
+        int retlen;
+        char *result;
+        
+	insize = max_t(unsigned int,
+		     INSIZE(readlink), OUTSIZE(readlink)+ *length);
+	UPARG(CODA_READLINK);
+
+        inp->coda_readlink.VFid = *fid;
+
+	error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
+	if (!error) {
+		retlen = outp->coda_readlink.count;
+		if (retlen >= *length)
+			retlen = *length - 1;
+		*length = retlen;
+		result =  (char *)outp + (long)outp->coda_readlink.data;
+		memcpy(buffer, result, retlen);
+		*(buffer + retlen) = '\0';
+	}
+
+	kvfree(inp);
+        return error;
+}
+
+
+
+int venus_link(struct super_block *sb, struct CodaFid *fid, 
+		  struct CodaFid *dirfid, const char *name, int len )
+{
+        union inputArgs *inp;
+        union outputArgs *outp;
+        int insize, outsize, error;
+        int offset;
+
+	offset = INSIZE(link);
+	insize = max_t(unsigned int, offset  + len + 1, OUTSIZE(link));
+        UPARG(CODA_LINK);
+
+        inp->coda_link.sourceFid = *fid;
+        inp->coda_link.destFid = *dirfid;
+        inp->coda_link.tname = offset;
+
+        /* make sure strings are null terminated */
+        memcpy((char *)(inp) + offset, name, len);
+        *((char *)inp + offset + len) = '\0';
+
+	error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
+
+	kvfree(inp);
+        return error;
+}
+
+int venus_symlink(struct super_block *sb, struct CodaFid *fid,
+		     const char *name, int len,
+		     const char *symname, int symlen)
+{
+        union inputArgs *inp;
+        union outputArgs *outp;
+        int insize, outsize, error;
+        int offset, s;
+
+        offset = INSIZE(symlink);
+	insize = max_t(unsigned int, offset + len + symlen + 8, OUTSIZE(symlink));
+	UPARG(CODA_SYMLINK);
+        
+        /*        inp->coda_symlink.attr = *tva; XXXXXX */ 
+        inp->coda_symlink.VFid = *fid;
+
+	/* Round up to word boundary and null terminate */
+        inp->coda_symlink.srcname = offset;
+        s = ( symlen  & ~0x3 ) + 4; 
+        memcpy((char *)(inp) + offset, symname, symlen);
+        *((char *)inp + offset + symlen) = '\0';
+        
+	/* Round up to word boundary and null terminate */
+        offset += s;
+        inp->coda_symlink.tname = offset;
+        s = (len & ~0x3) + 4;
+        memcpy((char *)(inp) + offset, name, len);
+        *((char *)inp + offset + len) = '\0';
+
+	error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
+
+	kvfree(inp);
+        return error;
+}
+
+int venus_fsync(struct super_block *sb, struct CodaFid *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_vcp(sb), insize, &outsize, inp);
+
+	kvfree(inp);
+	return error;
+}
+
+int venus_access(struct super_block *sb, struct CodaFid *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_vcp(sb), insize, &outsize, inp);
+
+	kvfree(inp);
+	return error;
+}
+
+
+int venus_pioctl(struct super_block *sb, struct CodaFid *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;
+        }
+
+        if (data->vi.out_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_vcp(sb), SIZE(ioctl) + data->vi.in_size,
+			    &outsize, inp);
+
+        if (error) {
+		pr_warn("%s: Venus returns: %d for %s\n",
+			__func__, error, coda_f2s(fid));
+		goto exit; 
+	}
+
+	if (outsize < (long)outp->coda_ioctl.data + outp->coda_ioctl.len) {
+		error = -EINVAL;
+		goto exit;
+	}
+        
+	/* Copy out the OUT buffer. */
+        if (outp->coda_ioctl.len > data->vi.out_size) {
+		error = -EINVAL;
+		goto exit;
+        }
+
+	/* Copy out the OUT buffer. */
+	if (copy_to_user(data->vi.out,
+			 (char *)outp + (long)outp->coda_ioctl.data,
+			 outp->coda_ioctl.len)) {
+		error = -EFAULT;
+		goto exit;
+	}
+
+ exit:
+	kvfree(inp);
+	return error;
+}
+
+int venus_statfs(struct dentry *dentry, struct kstatfs *sfs)
+{ 
+        union inputArgs *inp;
+        union outputArgs *outp;
+        int insize, outsize, error;
+        
+	insize = SIZE(statfs);
+	UPARG(CODA_STATFS);
+
+	error = coda_upcall(coda_vcp(dentry->d_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;
+	}
+
+	kvfree(inp);
+        return error;
+}
+
+int venus_access_intent(struct super_block *sb, struct CodaFid *fid,
+			bool *access_intent_supported,
+			size_t count, loff_t ppos, int type)
+{
+	union inputArgs *inp;
+	union outputArgs *outp;
+	int insize, outsize, error;
+	bool finalizer =
+		type == CODA_ACCESS_TYPE_READ_FINISH ||
+		type == CODA_ACCESS_TYPE_WRITE_FINISH;
+
+	if (!*access_intent_supported && !finalizer)
+		return 0;
+
+	insize = SIZE(access_intent);
+	UPARG(CODA_ACCESS_INTENT);
+
+	inp->coda_access_intent.VFid = *fid;
+	inp->coda_access_intent.count = count;
+	inp->coda_access_intent.pos = ppos;
+	inp->coda_access_intent.type = type;
+
+	error = coda_upcall(coda_vcp(sb), insize,
+			    finalizer ? NULL : &outsize, inp);
+
+	/*
+	 * we have to free the request buffer for synchronous upcalls
+	 * or when asynchronous upcalls fail, but not when asynchronous
+	 * upcalls succeed
+	 */
+	if (!finalizer || error)
+		kvfree(inp);
+
+	/* Chunked access is not supported or an old Coda client */
+	if (error == -EOPNOTSUPP) {
+		*access_intent_supported = false;
+		error = 0;
+	}
+	return error;
+}
+
+/*
+ * coda_upcall and coda_downcall routines.
+ */
+static void coda_block_signals(sigset_t *old)
+{
+	spin_lock_irq(&current->sighand->siglock);
+	*old = current->blocked;
+
+	sigfillset(&current->blocked);
+	sigdelset(&current->blocked, SIGKILL);
+	sigdelset(&current->blocked, SIGSTOP);
+	sigdelset(&current->blocked, SIGINT);
+
+	recalc_sigpending();
+	spin_unlock_irq(&current->sighand->siglock);
+}
+
+static void coda_unblock_signals(sigset_t *old)
+{
+	spin_lock_irq(&current->sighand->siglock);
+	current->blocked = *old;
+	recalc_sigpending();
+	spin_unlock_irq(&current->sighand->siglock);
+}
+
+/* Don't allow signals to interrupt the following upcalls before venus
+ * has seen them,
+ * - CODA_CLOSE or CODA_RELEASE upcall  (to avoid reference count problems)
+ * - CODA_STORE				(to avoid data loss)
+ * - CODA_ACCESS_INTENT                 (to avoid reference count problems)
+ */
+#define CODA_INTERRUPTIBLE(r) (!coda_hard && \
+			       (((r)->uc_opcode != CODA_CLOSE && \
+				 (r)->uc_opcode != CODA_STORE && \
+				 (r)->uc_opcode != CODA_ACCESS_INTENT && \
+				 (r)->uc_opcode != CODA_RELEASE) || \
+				(r)->uc_flags & CODA_REQ_READ))
+
+static inline void coda_waitfor_upcall(struct venus_comm *vcp,
+				       struct upc_req *req)
+{
+	DECLARE_WAITQUEUE(wait, current);
+	unsigned long timeout = jiffies + coda_timeout * HZ;
+	sigset_t old;
+	int blocked;
+
+	coda_block_signals(&old);
+	blocked = 1;
+
+	add_wait_queue(&req->uc_sleep, &wait);
+	for (;;) {
+		if (CODA_INTERRUPTIBLE(req))
+			set_current_state(TASK_INTERRUPTIBLE);
+		else
+			set_current_state(TASK_UNINTERRUPTIBLE);
+
+		/* got a reply */
+		if (req->uc_flags & (CODA_REQ_WRITE | CODA_REQ_ABORT))
+			break;
+
+		if (blocked && time_after(jiffies, timeout) &&
+		    CODA_INTERRUPTIBLE(req))
+		{
+			coda_unblock_signals(&old);
+			blocked = 0;
+		}
+
+		if (signal_pending(current)) {
+			list_del(&req->uc_chain);
+			break;
+		}
+
+		mutex_unlock(&vcp->vc_mutex);
+		if (blocked)
+			schedule_timeout(HZ);
+		else
+			schedule();
+		mutex_lock(&vcp->vc_mutex);
+	}
+	if (blocked)
+		coda_unblock_signals(&old);
+
+	remove_wait_queue(&req->uc_sleep, &wait);
+	set_current_state(TASK_RUNNING);
+}
+
+
+/*
+ * 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 venus_comm *vcp,
+		       int inSize, int *outSize,
+		       union inputArgs *buffer)
+{
+	union outputArgs *out;
+	union inputArgs *sig_inputArgs;
+	struct upc_req *req = NULL, *sig_req;
+	int error;
+
+	mutex_lock(&vcp->vc_mutex);
+
+	if (!vcp->vc_inuse) {
+		pr_notice("Venus dead, not sending upcall\n");
+		error = -ENXIO;
+		goto exit;
+	}
+
+	/* Format the request message. */
+	req = kmalloc(sizeof(struct upc_req), GFP_KERNEL);
+	if (!req) {
+		error = -ENOMEM;
+		goto exit;
+	}
+
+	buffer->ih.unique = ++vcp->vc_seq;
+
+	req->uc_data = (void *)buffer;
+	req->uc_flags = outSize ? 0 : CODA_REQ_ASYNC;
+	req->uc_inSize = inSize;
+	req->uc_outSize = (outSize && *outSize) ? *outSize : inSize;
+	req->uc_opcode = buffer->ih.opcode;
+	req->uc_unique = buffer->ih.unique;
+	init_waitqueue_head(&req->uc_sleep);
+
+	/* Append msg to pending queue and poke Venus. */
+	list_add_tail(&req->uc_chain, &vcp->vc_pending);
+	wake_up_interruptible(&vcp->vc_waitq);
+
+	/* We can return early on asynchronous requests */
+	if (outSize == NULL) {
+		mutex_unlock(&vcp->vc_mutex);
+		return 0;
+	}
+
+	/* 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. */
+	coda_waitfor_upcall(vcp, req);
+
+	/* Op went through, interrupt or not... */
+	if (req->uc_flags & CODA_REQ_WRITE) {
+		out = (union outputArgs *)req->uc_data;
+		/* here we map positive Venus errors to kernel errors */
+		error = -out->oh.result;
+		*outSize = req->uc_outSize;
+		goto exit;
+	}
+
+	error = -EINTR;
+	if ((req->uc_flags & CODA_REQ_ABORT) || !signal_pending(current)) {
+		pr_warn("Unexpected interruption.\n");
+		goto exit;
+	}
+
+	/* Interrupted before venus read it. */
+	if (!(req->uc_flags & CODA_REQ_READ))
+		goto exit;
+
+	/* Venus saw the upcall, make sure we can send interrupt signal */
+	if (!vcp->vc_inuse) {
+		pr_info("Venus dead, not sending signal.\n");
+		goto exit;
+	}
+
+	error = -ENOMEM;
+	sig_req = kmalloc(sizeof(struct upc_req), GFP_KERNEL);
+	if (!sig_req) goto exit;
+
+	sig_inputArgs = kvzalloc(sizeof(*sig_inputArgs), GFP_KERNEL);
+	if (!sig_inputArgs) {
+		kfree(sig_req);
+		goto exit;
+	}
+
+	error = -EINTR;
+	sig_inputArgs->ih.opcode = CODA_SIGNAL;
+	sig_inputArgs->ih.unique = req->uc_unique;
+
+	sig_req->uc_flags = CODA_REQ_ASYNC;
+	sig_req->uc_opcode = sig_inputArgs->ih.opcode;
+	sig_req->uc_unique = sig_inputArgs->ih.unique;
+	sig_req->uc_data = (void *)sig_inputArgs;
+	sig_req->uc_inSize = sizeof(struct coda_in_hdr);
+	sig_req->uc_outSize = sizeof(struct coda_in_hdr);
+
+	/* insert at head of queue! */
+	list_add(&(sig_req->uc_chain), &vcp->vc_pending);
+	wake_up_interruptible(&vcp->vc_waitq);
+
+exit:
+	kfree(req);
+	mutex_unlock(&vcp->vc_mutex);
+	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 CodaFid with another throughout the name cache */
+
+int coda_downcall(struct venus_comm *vcp, int opcode, union outputArgs *out,
+		  size_t nbytes)
+{
+	struct inode *inode = NULL;
+	struct CodaFid *fid = NULL, *newfid;
+	struct super_block *sb;
+
+	/*
+	 * Make sure we have received enough data from the cache
+	 * manager to populate the necessary fields in the buffer
+	 */
+	switch (opcode) {
+	case CODA_PURGEUSER:
+		if (nbytes < sizeof(struct coda_purgeuser_out))
+			return -EINVAL;
+		break;
+
+	case CODA_ZAPDIR:
+		if (nbytes < sizeof(struct coda_zapdir_out))
+			return -EINVAL;
+		break;
+
+	case CODA_ZAPFILE:
+		if (nbytes < sizeof(struct coda_zapfile_out))
+			return -EINVAL;
+		break;
+
+	case CODA_PURGEFID:
+		if (nbytes < sizeof(struct coda_purgefid_out))
+			return -EINVAL;
+		break;
+
+	case CODA_REPLACE:
+		if (nbytes < sizeof(struct coda_replace_out))
+			return -EINVAL;
+		break;
+	}
+
+	/* Handle invalidation requests. */
+	mutex_lock(&vcp->vc_mutex);
+	sb = vcp->vc_sb;
+	if (!sb || !sb->s_root)
+		goto unlock_out;
+
+	switch (opcode) {
+	case CODA_FLUSH:
+		coda_cache_clear_all(sb);
+		shrink_dcache_sb(sb);
+		if (d_really_is_positive(sb->s_root))
+			coda_flag_inode(d_inode(sb->s_root), C_FLUSH);
+		break;
+
+	case CODA_PURGEUSER:
+		coda_cache_clear_all(sb);
+		break;
+
+	case CODA_ZAPDIR:
+		fid = &out->coda_zapdir.CodaFid;
+		break;
+
+	case CODA_ZAPFILE:
+		fid = &out->coda_zapfile.CodaFid;
+		break;
+
+	case CODA_PURGEFID:
+		fid = &out->coda_purgefid.CodaFid;
+		break;
+
+	case CODA_REPLACE:
+		fid = &out->coda_replace.OldFid;
+		break;
+	}
+	if (fid)
+		inode = coda_fid_to_inode(fid, sb);
+
+unlock_out:
+	mutex_unlock(&vcp->vc_mutex);
+
+	if (!inode)
+		return 0;
+
+	switch (opcode) {
+	case CODA_ZAPDIR:
+		coda_flag_inode_children(inode, C_PURGE);
+		coda_flag_inode(inode, C_VATTR);
+		break;
+
+	case CODA_ZAPFILE:
+		coda_flag_inode(inode, C_VATTR);
+		break;
+
+	case CODA_PURGEFID:
+		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);
+		break;
+
+	case CODA_REPLACE:
+		newfid = &out->coda_replace.NewFid;
+		coda_replace_fid(inode, fid, newfid);
+		break;
+	}
+	iput(inode);
+	return 0;
+}