[Qemu-devel] [PATCH -v2 22/22] virtio-9p: Update existing fid path on rename

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

We need to make sure that we update the path component of the existing
fid's when we rename a file. The client is not expected to clunk these fids
pointing to the old name. If we don't update any operation on the old unopened
fid will point to the old name and will fail

Add BUG_ON to make sure when we clone a fid, we don't have open descriptor
attached to the fid. We also need to make sure that when we open a fid, the
specified fid should not already be opened. Capture the case by adding a BUG_ON

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 hw/virtio-9p.c |   39 +++++++++++++++++++++++++++++++++++++++
 1 files changed, 39 insertions(+), 0 deletions(-)

diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c
index c8ab6b6..9aa4b72 100644
--- a/hw/virtio-9p.c
+++ b/hw/virtio-9p.c
@@ -955,6 +955,9 @@ static void v9fs_walk(V9fsState *s, V9fsPDU *pdu)
 
     /* FIXME: is this really valid? */
     if (fid == newfid) {
+
+        BUG_ON(vs->fidp->fd != -1);
+        BUG_ON(vs->fidp->dir);
         v9fs_string_init(&vs->path);
         vs->name_idx = 0;
 
@@ -1120,6 +1123,9 @@ static void v9fs_open(V9fsState *s, V9fsPDU *pdu)
         goto out;
     }
 
+    BUG_ON(vs->fidp->fd != -1);
+    BUG_ON(vs->fidp->dir);
+
     err = posix_lstat(s, &vs->fidp->path, &vs->stbuf);
 
     v9fs_open_post_lstat(s, vs, err);
@@ -1877,8 +1883,19 @@ out:
     qemu_free(vs);
 }
 
+static void v9fs_fix_path(V9fsString *dst, V9fsString *src, int len)
+{
+    V9fsString str;
+    v9fs_string_init(&str);
+    v9fs_string_copy(&str, dst);
+    v9fs_string_sprintf(dst, "%s%s", src->data, str.data+len);
+    v9fs_string_free(&str);
+}
+
+
 static void v9fs_wstat_post_chown(V9fsState *s, V9fsWstatState *vs, int err)
 {
+    V9fsFidState *fidp;
     if (err < 0) {
         goto out;
     }
@@ -1905,6 +1922,28 @@ static void v9fs_wstat_post_chown(V9fsState *s, V9fsWstatState *vs, int err)
         if (strcmp(new_name, vs->fidp->path.data) != 0) {
             if (posix_rename(s, &vs->fidp->path, &vs->nname)) {
                 err = -errno;
+            } else {
+                /*
+                 * Fixup fid's pointing to the old name to
+                 * start pointing to the new name
+                 */
+                for (fidp = s->fid_list; fidp; fidp = fidp->next) {
+
+                    if (vs->fidp == fidp) {
+                        /*
+                         * we replace name of this fid towards the end
+                         * so that our below strcmp will work
+                         */
+                        continue;
+                    }
+                    if (!strncmp(vs->fidp->path.data, fidp->path.data,
+                                 strlen(vs->fidp->path.data))) {
+                        /* replace the name */
+                        v9fs_fix_path(&fidp->path, &vs->nname,
+                                      strlen(vs->fidp->path.data));
+                    }
+                }
+                v9fs_string_copy(&vs->fidp->path, &vs->nname);
             }
         }
     }
-- 
1.7.0.2.273.gc2413