Patchwork [-V3,5/8] hw/9pfs: Add open flag to fid

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Submitter Aneesh Kumar K.V
Date March 5, 2011, 5:52 p.m.
Message ID <1299347533-17047-5-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
Download mbox | patch
Permalink /patch/85540/
State New
Headers show

Comments

Aneesh Kumar K.V - March 5, 2011, 5:52 p.m.
We use this flag when we reopen the file. We need
to track open flag because if the open request have
flags like O_SYNC, we want to open the file with same flag
in host too

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 hw/9pfs/virtio-9p.c |   56 +++++++++++++++++++++++++++++++++++++++++---------
 hw/9pfs/virtio-9p.h |    1 +
 2 files changed, 47 insertions(+), 10 deletions(-)
Stefan Hajnoczi - March 13, 2011, 4:38 p.m.
On Sat, Mar 5, 2011 at 5:52 PM, Aneesh Kumar K.V
<aneesh.kumar@linux.vnet.ibm.com> wrote:
> +static int get_dotl_openflags(int oflags)
> +{
> +    int flags;
> +    /*
> +     * Since we can share the fd between multiple fids,
> +     * open the file in read write mode
> +     */

I didn't know that fds are shared between fids.  Also this code does
not always open O_RDWR.  This comment is incorrect (perhaps a later
patch changes assumptions, I haven't looked yet, but introducing
temporary inconsistencies makes it difficult to review and potentially
confusing for git-bisect users).

Stefan
Aneesh Kumar K.V - March 13, 2011, 7:01 p.m.
On Sun, 13 Mar 2011 16:38:39 +0000, Stefan Hajnoczi <stefanha@gmail.com> wrote:
> On Sat, Mar 5, 2011 at 5:52 PM, Aneesh Kumar K.V
> <aneesh.kumar@linux.vnet.ibm.com> wrote:
> > +static int get_dotl_openflags(int oflags)
> > +{
> > +    int flags;
> > +    /*
> > +     * Since we can share the fd between multiple fids,
> > +     * open the file in read write mode
> > +     */
> 
> I didn't know that fds are shared between fids.  Also this code does
> not always open O_RDWR.  This comment is incorrect (perhaps a later
> patch changes assumptions, I haven't looked yet, but introducing
> temporary inconsistencies makes it difficult to review and potentially
> confusing for git-bisect users).
> 

What i wanted to say there was, we can possibly look at sharing fd
between multiple fids. Will update the comment.

-aneesh

Patch

diff --git a/hw/9pfs/virtio-9p.c b/hw/9pfs/virtio-9p.c
index ce09e55..1fa7256 100644
--- a/hw/9pfs/virtio-9p.c
+++ b/hw/9pfs/virtio-9p.c
@@ -22,6 +22,8 @@ 
 int debug_9p_pdu;
 static void v9fs_reclaim_fd(V9fsState *s);
 
+#define PASS_OPEN_FLAG (O_SYNC | O_DSYNC | O_RSYNC |  \
+                        O_EXCL)
 enum {
     Oread   = 0x00,
     Owrite  = 0x01,
@@ -68,6 +70,28 @@  static int omode_to_uflags(int8_t mode)
     return ret;
 }
 
+static int get_dotl_openflags(int oflags)
+{
+    int flags;
+    /*
+     * Since we can share the fd between multiple fids,
+     * open the file in read write mode
+     */
+    if ((oflags & O_ACCMODE) != O_RDONLY) {
+        flags = O_RDWR;
+    } else {
+        flags = O_RDONLY;
+    }
+    /*
+     * If the client asked for any of the below flags we
+     * should open the file with same open flag
+     */
+    if (oflags & PASS_OPEN_FLAG) {
+        flags |=  oflags & PASS_OPEN_FLAG;
+    }
+    return flags;
+}
+
 void cred_init(FsCred *credp)
 {
     credp->fc_uid = -1;
@@ -456,9 +480,9 @@  static V9fsFidState *lookup_fid(V9fsState *s, int32_t fid)
              * descriptors.
              */
             if (f->fsmap.fid_type == P9_FID_FILE) {
-                /* FIXME!! should we remember the open flags ?*/
                 if (f->fsmap.fs.fd == -1) {
-                    f->fsmap.fs.fd = v9fs_do_open(s, &f->fsmap.path, O_RDWR);
+                    f->fsmap.fs.fd = v9fs_do_open(s, &f->fsmap.path,
+                                                  f->fsmap.open_flags);
                 }
             }
             /*
@@ -1815,14 +1839,19 @@  static void v9fs_open_post_lstat(V9fsState *s, V9fsOpenState *vs, int err)
         v9fs_open_post_opendir(s, vs, err);
     } else {
         if (s->proto_version == V9FS_PROTO_2000L) {
-            flags = vs->mode;
-            flags &= ~(O_NOCTTY | O_ASYNC | O_CREAT);
-            /* Ignore direct disk access hint until the server supports it. */
-            flags &= ~O_DIRECT;
+            flags = get_dotl_openflags(vs->mode);
         } else {
             flags = omode_to_uflags(vs->mode);
         }
         vs->fidp->fsmap.fs.fd = v9fs_do_open(s, &vs->fidp->fsmap.path, flags);
+        vs->fidp->fsmap.open_flags = flags;
+        if (flags & O_EXCL) {
+            /*
+             * We let the host file system do O_EXCL check
+             * We should not reclaim such fd
+             */
+            vs->fidp->fsmap.flags  |= FID_NON_RECLAIMABLE;
+        }
         v9fs_open_post_open(s, vs, err);
     }
     return;
@@ -1941,11 +1970,17 @@  static void v9fs_lcreate(V9fsState *s, V9fsPDU *pdu)
     v9fs_string_sprintf(&vs->fullname, "%s/%s", vs->fidp->fsmap.path.data,
              vs->name.data);
 
-    /* Ignore direct disk access hint until the server supports it. */
-    flags &= ~O_DIRECT;
-
+    flags = get_dotl_openflags(flags);
     vs->fidp->fsmap.fs.fd = v9fs_do_open2(s, vs->fullname.data, vs->fidp->uid,
-            gid, flags, mode);
+                                          gid, flags | O_CREAT, mode);
+    vs->fidp->fsmap.open_flags = flags;
+    if (flags & O_EXCL) {
+        /*
+         * We let the host file system do O_EXCL check
+         * We should not reclaim such fd
+         */
+        vs->fidp->fsmap.flags  |= FID_NON_RECLAIMABLE;
+    }
     v9fs_lcreate_post_do_open2(s, vs, err);
     return;
 
@@ -2653,6 +2688,7 @@  static void v9fs_create_post_lstat(V9fsState *s, V9fsCreateState *vs, int err)
                                               -1,
                                               omode_to_uflags(vs->mode)|O_CREAT,
                                               vs->perm);
+        vs->fidp->fsmap.open_flags = omode_to_uflags(vs->mode);
         v9fs_create_post_open2(s, vs, err);
     }
 
diff --git a/hw/9pfs/virtio-9p.h b/hw/9pfs/virtio-9p.h
index b0f8210..10809ba 100644
--- a/hw/9pfs/virtio-9p.h
+++ b/hw/9pfs/virtio-9p.h
@@ -196,6 +196,7 @@  typedef struct V9fsfidmap {
         DIR *dir;
         V9fsXattr xattr;
     } fs;
+    int open_flags;
     int fid_type;
     V9fsString path;
     int flags;