1 files changed, 40 insertions, 23 deletions

diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index 0cd0c14c2a..aebadeaa03 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -1766,9 +1766,9 @@ static bool same_stat_id(const struct stat *a, const struct stat *b)
 
 static void coroutine_fn v9fs_walk(void *opaque)
 {
-    int name_idx;
+    int name_idx, nwalked;
     g_autofree V9fsQID *qids = NULL;
-    int i, err = 0;
+    int i, err = 0, any_err = 0;
     V9fsPath dpath, path;
     P9ARRAY_REF(V9fsPath) pathes = NULL;
     uint16_t nwnames;
@@ -1834,54 +1834,61 @@ static void coroutine_fn v9fs_walk(void *opaque)
      * driver code altogether inside the following block.
      */
     v9fs_co_run_in_worker({
+        nwalked = 0;
         if (v9fs_request_cancelled(pdu)) {
-            err = -EINTR;
+            any_err |= err = -EINTR;
             break;
         }
         err = s->ops->lstat(&s->ctx, &dpath, &fidst);
         if (err < 0) {
-            err = -errno;
+            any_err |= err = -errno;
             break;
         }
         stbuf = fidst;
-        for (name_idx = 0; name_idx < nwnames; name_idx++) {
+        for (; nwalked < nwnames; nwalked++) {
             if (v9fs_request_cancelled(pdu)) {
-                err = -EINTR;
+                any_err |= err = -EINTR;
                 break;
             }
             if (!same_stat_id(&pdu->s->root_st, &stbuf) ||
-                strcmp("..", wnames[name_idx].data))
+                strcmp("..", wnames[nwalked].data))
             {
                 err = s->ops->name_to_path(&s->ctx, &dpath,
-                                           wnames[name_idx].data,
-                                           &pathes[name_idx]);
+                                           wnames[nwalked].data,
+                                           &pathes[nwalked]);
                 if (err < 0) {
-                    err = -errno;
+                    any_err |= err = -errno;
                     break;
                 }
                 if (v9fs_request_cancelled(pdu)) {
-                    err = -EINTR;
+                    any_err |= err = -EINTR;
                     break;
                 }
-                err = s->ops->lstat(&s->ctx, &pathes[name_idx], &stbuf);
+                err = s->ops->lstat(&s->ctx, &pathes[nwalked], &stbuf);
                 if (err < 0) {
-                    err = -errno;
+                    any_err |= err = -errno;
                     break;
                 }
-                stbufs[name_idx] = stbuf;
-                v9fs_path_copy(&dpath, &pathes[name_idx]);
+                stbufs[nwalked] = stbuf;
+                v9fs_path_copy(&dpath, &pathes[nwalked]);
             }
         }
     });
     /*
      * Handle all the rest of this Twalk request on main thread ...
+     *
+     * NOTE: -EINTR is an exception where we deviate from the protocol spec
+     * and simply send a (R)Lerror response instead of bothering to assemble
+     * a (deducted) Rwalk response; because -EINTR is always the result of a
+     * Tflush request, so client would no longer wait for a response in this
+     * case anyway.
      */
-    if (err < 0) {
+    if ((err < 0 && !nwalked) || err == -EINTR) {
         goto out;
     }
 
-    err = stat_to_qid(pdu, &fidst, &qid);
-    if (err < 0) {
+    any_err |= err = stat_to_qid(pdu, &fidst, &qid);
+    if (err < 0 && !nwalked) {
         goto out;
     }
     stbuf = fidst;
@@ -1890,20 +1897,29 @@ static void coroutine_fn v9fs_walk(void *opaque)
     v9fs_path_copy(&dpath, &fidp->path);
     v9fs_path_copy(&path, &fidp->path);
 
-    for (name_idx = 0; name_idx < nwnames; name_idx++) {
+    for (name_idx = 0; name_idx < nwalked; name_idx++) {
         if (!same_stat_id(&pdu->s->root_st, &stbuf) ||
             strcmp("..", wnames[name_idx].data))
         {
             stbuf = stbufs[name_idx];
-            err = stat_to_qid(pdu, &stbuf, &qid);
+            any_err |= err = stat_to_qid(pdu, &stbuf, &qid);
             if (err < 0) {
-                goto out;
+                break;
             }
             v9fs_path_copy(&path, &pathes[name_idx]);
             v9fs_path_copy(&dpath, &path);
         }
         memcpy(&qids[name_idx], &qid, sizeof(qid));
     }
+    if (any_err < 0) {
+        if (!name_idx) {
+            /* don't send any QIDs, send Rlerror instead */
+            goto out;
+        } else {
+            /* send QIDs (not Rlerror), but fid MUST remain unaffected */
+            goto send_qids;
+        }
+    }
     if (fid == newfid) {
         if (fidp->fid_type != P9_FID_NONE) {
             err = -EINVAL;
@@ -1921,8 +1937,9 @@ static void coroutine_fn v9fs_walk(void *opaque)
         newfidp->uid = fidp->uid;
         v9fs_path_copy(&newfidp->path, &path);
     }
-    err = v9fs_walk_marshal(pdu, nwnames, qids);
-    trace_v9fs_walk_return(pdu->tag, pdu->id, nwnames, qids);
+send_qids:
+    err = v9fs_walk_marshal(pdu, name_idx, qids);
+    trace_v9fs_walk_return(pdu->tag, pdu->id, name_idx, qids);
 out:
     put_fid(pdu, fidp);
     if (newfidp) {