[src/trunk]: src/sys/rump/librump/rumpvfs * open backend device once when the...

[pooka <pooka%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/30e25a22963e
branches:  trunk
changeset: 761632:30e25a22963e
user:      pooka <pooka%NetBSD.org@localhost>
date:      Thu Feb 03 15:36:30 2011 +0000

description:
* open backend device once when the rumpblk is registered instead of
  every time the virtual device is opened.  this takes care of e.g.
  a midlife chmod crisis
* when mapping initial windows, consistently look at host size and
  host offset.  otherwise we might end up in a situation with 0
  initial windows mapped, and that will cause a crash later.

diffstat:

 sys/rump/librump/rumpvfs/rumpblk.c |  115 +++++++++++++++++++++++++++---------
 1 files changed, 87 insertions(+), 28 deletions(-)

diffs (213 lines):

diff -r 95c6795d1f71 -r 30e25a22963e sys/rump/librump/rumpvfs/rumpblk.c
--- a/sys/rump/librump/rumpvfs/rumpblk.c        Thu Feb 03 11:25:27 2011 +0000
+++ b/sys/rump/librump/rumpvfs/rumpblk.c        Thu Feb 03 15:36:30 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: rumpblk.c,v 1.44 2011/02/03 10:06:06 pooka Exp $       */
+/*     $NetBSD: rumpblk.c,v 1.45 2011/02/03 15:36:30 pooka Exp $       */
 
 /*
  * Copyright (c) 2009 Antti Kantee.  All Rights Reserved.
@@ -52,7 +52,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: rumpblk.c,v 1.44 2011/02/03 10:06:06 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: rumpblk.c,v 1.45 2011/02/03 15:36:30 pooka Exp $");
 
 #include <sys/param.h>
 #include <sys/buf.h>
@@ -71,6 +71,15 @@
 #include "rump_private.h"
 #include "rump_vfs_private.h"
 
+/*
+ * O_DIRECT is the fastest alternative, but since it falls back to
+ * non-direct writes silently, I am not sure it will always be 100% safe.
+ * Use it and play with it, but do that with caution.
+ */
+#if 0
+#define HAS_ODIRECT
+#endif
+
 #if 0
 #define DPRINTF(x) printf x
 #else
@@ -99,6 +108,7 @@
 static struct rblkdev {
        char *rblk_path;
        int rblk_fd;
+       int rblk_mode;
 #ifdef HAS_ODIRECT
        int rblk_dfd;
 #endif
@@ -152,6 +162,9 @@
        rumpblk_ioctl, nostop, notty, nopoll, nommap, nokqfilter, D_DISK
 };
 
+static int backend_open(struct rblkdev *, const char *);
+static int backend_close(struct rblkdev *);
+
 /* fail every n out of BLKFAIL_MAX */
 #define BLKFAIL_MAX 10000
 static int blkfail;
@@ -422,10 +435,12 @@
        }
 
        rblk = &minors[i];
+       rblk->rblk_path = __UNCONST("taken");
+       mutex_exit(&rumpblk_lock);
+
        len = strlen(path);
        rblk->rblk_path = malloc(len + 1, M_TEMP, M_WAITOK);
        strcpy(rblk->rblk_path, path);
-       rblk->rblk_fd = -1;
        rblk->rblk_hostoffset = offset;
        if (size != RUMPBLK_SIZENOTSET) {
                KASSERT(size + offset <= flen);
@@ -437,7 +452,13 @@
        rblk->rblk_hostsize = flen;
        rblk->rblk_ftype = ftype;
        makedefaultlabel(&rblk->rblk_label, rblk->rblk_size, i);
-       mutex_exit(&rumpblk_lock);
+
+       if ((error = backend_open(rblk, path)) != 0) {
+               memset(&rblk->rblk_label, 0, sizeof(rblk->rblk_label));
+               free(rblk->rblk_path, M_TEMP);
+               rblk->rblk_path = NULL;
+               return error;
+       }
 
        *dmin = i;
        return 0;
@@ -465,41 +486,52 @@
                return ENOENT;
 
        rblk = &minors[i];
-       KASSERT(rblk->rblk_fd == -1);
+       backend_close(rblk);
 
        wincleanup(rblk);
        free(rblk->rblk_path, M_TEMP);
+       memset(&rblk->rblk_label, 0, sizeof(rblk->rblk_label));
        rblk->rblk_path = NULL;
-       memset(&rblk->rblk_label, 0, sizeof(rblk->rblk_label));
 
        return 0;
 }
 
-int
-rumpblk_open(dev_t dev, int flag, int fmt, struct lwp *l)
+static int
+backend_open(struct rblkdev *rblk, const char *path)
 {
-       struct rblkdev *rblk = &minors[minor(dev)];
        int error, fd;
 
-       if (rblk->rblk_path == NULL)
-               return ENXIO;
-
-       if (rblk->rblk_fd != -1)
-               return 0; /* XXX: refcount, open mode */
-       flag &= ~O_TRUNC;
-       fd = rumpuser_open(rblk->rblk_path, OFLAGS(flag), &error);
-       if (error)
-               return error;
+       KASSERT(rblk->rblk_fd != -1);
+       fd = rumpuser_open(path, O_RDWR, &error);
+       if (error) {
+               fd = rumpuser_open(path, O_RDONLY, &error);
+               if (error)
+                       return error;
+               rblk->rblk_mode = FREAD;
 
 #ifdef HAS_ODIRECT
-       rblk->rblk_dfd = rumpuser_open(rblk->rblk_path,
-           OFLAGS(flag) | O_DIRECT, &error);
-       if (error)
-               return error;
+               rblk->rblk_dfd = rumpuser_open(path,
+                   O_RDONLY | O_DIRECT, &error);
+               if (error) {
+                       close(fd);
+                       return error;
+               }
 #endif
+       } else {
+               rblk->rblk_mode = FREAD|FWRITE;
+
+#ifdef HAS_ODIRECT
+               rblk->rblk_dfd = rumpuser_open(path,
+                   O_RDWR | O_DIRECT, &error);
+               if (error) {
+                       close(fd);
+                       return error;
+               }
+#endif
+       }
 
        if (rblk->rblk_ftype == RUMPUSER_FT_REG) {
-               uint64_t fsize = rblk->rblk_size, off = rblk->rblk_hostoffset;
+               uint64_t fsize= rblk->rblk_hostsize, off= rblk->rblk_hostoffset;
                struct blkwin *win;
                int i, winsize;
 
@@ -510,9 +542,9 @@
                 */
 
                rblk->rblk_mmflags = 0;
-               if (flag & FREAD)
+               if (rblk->rblk_mode & FREAD)
                        rblk->rblk_mmflags |= RUMPUSER_FILEMMAP_READ;
-               if (flag & FWRITE) {
+               if (rblk->rblk_mode & FWRITE) {
                        rblk->rblk_mmflags |= RUMPUSER_FILEMMAP_WRITE;
                        rblk->rblk_mmflags |= RUMPUSER_FILEMMAP_SHARED;
                }
@@ -548,10 +580,9 @@
        return 0;
 }
 
-int
-rumpblk_close(dev_t dev, int flag, int fmt, struct lwp *l)
+static int
+backend_close(struct rblkdev *rblk)
 {
-       struct rblkdev *rblk = &minors[minor(dev)];
        int dummy;
 
        if (rblk->rblk_mmflags)
@@ -559,6 +590,34 @@
        rumpuser_fsync(rblk->rblk_fd, &dummy);
        rumpuser_close(rblk->rblk_fd, &dummy);
        rblk->rblk_fd = -1;
+#ifdef HAS_ODIRECT
+       if (rblk->rblk_dfd != -1) {
+               rumpuser_close(rblk->rblk_dfd, &dummy);
+               rblk->rblk_dfd = -1;
+       }
+#endif
+
+       return 0;
+}
+
+int
+rumpblk_open(dev_t dev, int flag, int fmt, struct lwp *l)
+{
+       struct rblkdev *rblk = &minors[minor(dev)];
+
+       if (rblk->rblk_fd == -1)
+               return ENXIO;
+
+       if (((flag & (FREAD|FWRITE)) & ~rblk->rblk_mode) != 0) {
+               return EACCES;
+       }
+
+       return 0;
+}
+
+int
+rumpblk_close(dev_t dev, int flag, int fmt, struct lwp *l)
+{
 
        return 0;
 }