[Qemu-devel] [PATCH] Fix bug with virtio-9p rename

[Sassan Panahinejad <sassan@sassan.me.uk>]

After renaming a file, any existing references to the file are updated.
However, in addition to this, it would update any files whos names began with that of the file being moved.
Therefore when renaming somefile.txt to somefile.txt-old, any references to somefile.txt-new became somefile.txt-old-new.
This breaks debconf and probably many other applications.
This patch fixes the problem. Now only files exactly matching, or files which are a subdirectory of a directory being moved are affected.

Signed-off-by: Sassan Panahinejad <sassan@sassan.me.uk>
---
 hw/virtio-9p.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c
index 2530f6d..a2f096d 100644
--- a/hw/virtio-9p.c
+++ b/hw/virtio-9p.c
@@ -2810,8 +2810,15 @@ static int v9fs_complete_rename(V9fsState *s, V9fsRenameState *vs)
                     */
                     continue;
                 }
+                /*
+                * Fix the name if
+                * A: The file is the one we're moving
+                * Or B: The file is a subdirectory of one we're moving
+                */
                 if (!strncmp(vs->fidp->path.data, fidp->path.data,
-                    strlen(vs->fidp->path.data))) {
+                    strlen(vs->fidp->path.data)) &&
+                    (strlen(vs->fidp->path.data) == strlen(fidp->path.data) ||
+                    fidp->path.data[strlen(vs->fidp->path.data)] == '/')) {
                     /* replace the name */
                     v9fs_fix_path(&fidp->path, &vs->name,
                                   strlen(vs->fidp->path.data));
-- 
1.7.0.4