Merge remote-tracking branch 'remotes/cschoenebeck/tags/pull-9p-20200812' into staging

9pfs: Fix severe performance issue of Treaddir requests.

# gpg: Signature made Wed 12 Aug 2020 11:06:21 BST
# gpg:                using RSA key 96D8D110CF7AF8084F88590134C2B58765A47395
# gpg:                issuer "qemu_oss@crudebyte.com"
# gpg: Good signature from "Christian Schoenebeck <qemu_oss@crudebyte.com>" [unknown]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: ECAB 1A45 4014 1413 BA38  4926 30DB 47C3 A012 D5F4
#      Subkey fingerprint: 96D8 D110 CF7A F808 4F88  5901 34C2 B587 65A4 7395

* remotes/cschoenebeck/tags/pull-9p-20200812:
  9pfs: clarify latency of v9fs_co_run_in_worker()
  9pfs: differentiate readdir lock between 9P2000.u vs. 9P2000.L
  9pfs: T_readdir latency optimization
  9pfs: add new function v9fs_co_readdir_many()
  9pfs: split out fs driver core of v9fs_co_readdir()
  9pfs: make v9fs_readdir_response_size() public
  tests/virtio-9p: added split readdir tests

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 108 insertions, 0 deletions

diff --git a/tests/qtest/virtio-9p-test.c b/tests/qtest/virtio-9p-test.c
index 2167322..de30b71 100644
--- a/tests/qtest/virtio-9p-test.c
+++ b/tests/qtest/virtio-9p-test.c
@@ -578,6 +578,7 @@ static bool fs_dirents_contain_name(struct V9fsDirent *e, const char* name)
     return false;
 }
 
+/* basic readdir test where reply fits into a single response message */
 static void fs_readdir(void *obj, void *data, QGuestAllocator *t_alloc)
 {
     QVirtio9P *v9p = obj;
@@ -631,6 +632,89 @@ static void fs_readdir(void *obj, void *data, QGuestAllocator *t_alloc)
     g_free(wnames[0]);
 }
 
+/* readdir test where overall request is split over several messages */
+static void fs_readdir_split(void *obj, void *data, QGuestAllocator *t_alloc,
+                             uint32_t count)
+{
+    QVirtio9P *v9p = obj;
+    alloc = t_alloc;
+    char *const wnames[] = { g_strdup(QTEST_V9FS_SYNTH_READDIR_DIR) };
+    uint16_t nqid;
+    v9fs_qid qid;
+    uint32_t nentries, npartialentries;
+    struct V9fsDirent *entries, *tail, *partialentries;
+    P9Req *req;
+    int fid;
+    uint64_t offset;
+
+    fs_attach(v9p, NULL, t_alloc);
+
+    fid = 1;
+    offset = 0;
+    entries = NULL;
+    nentries = 0;
+    tail = NULL;
+
+    req = v9fs_twalk(v9p, 0, fid, 1, wnames, 0);
+    v9fs_req_wait_for_reply(req, NULL);
+    v9fs_rwalk(req, &nqid, NULL);
+    g_assert_cmpint(nqid, ==, 1);
+
+    req = v9fs_tlopen(v9p, fid, O_DIRECTORY, 0);
+    v9fs_req_wait_for_reply(req, NULL);
+    v9fs_rlopen(req, &qid, NULL);
+
+    /*
+     * send as many Treaddir requests as required to get all directory
+     * entries
+     */
+    while (true) {
+        npartialentries = 0;
+        partialentries = NULL;
+
+        req = v9fs_treaddir(v9p, fid, offset, count, 0);
+        v9fs_req_wait_for_reply(req, NULL);
+        v9fs_rreaddir(req, &count, &npartialentries, &partialentries);
+        if (npartialentries > 0 && partialentries) {
+            if (!entries) {
+                entries = partialentries;
+                nentries = npartialentries;
+                tail = partialentries;
+            } else {
+                tail->next = partialentries;
+                nentries += npartialentries;
+            }
+            while (tail->next) {
+                tail = tail->next;
+            }
+            offset = tail->offset;
+        } else {
+            break;
+        }
+    }
+
+    g_assert_cmpint(
+        nentries, ==,
+        QTEST_V9FS_SYNTH_READDIR_NFILES + 2 /* "." and ".." */
+    );
+
+    /*
+     * Check all file names exist in returned entries, ignore their order
+     * though.
+     */
+    g_assert_cmpint(fs_dirents_contain_name(entries, "."), ==, true);
+    g_assert_cmpint(fs_dirents_contain_name(entries, ".."), ==, true);
+    for (int i = 0; i < QTEST_V9FS_SYNTH_READDIR_NFILES; ++i) {
+        char *name = g_strdup_printf(QTEST_V9FS_SYNTH_READDIR_FILE, i);
+        g_assert_cmpint(fs_dirents_contain_name(entries, name), ==, true);
+        g_free(name);
+    }
+
+    v9fs_free_dirents(entries);
+
+    g_free(wnames[0]);
+}
+
 static void fs_walk_no_slash(void *obj, void *data, QGuestAllocator *t_alloc)
 {
     QVirtio9P *v9p = obj;
@@ -793,6 +877,24 @@ static void fs_flush_ignored(void *obj, void *data, QGuestAllocator *t_alloc)
     g_free(wnames[0]);
 }
 
+static void fs_readdir_split_128(void *obj, void *data,
+                                 QGuestAllocator *t_alloc)
+{
+    fs_readdir_split(obj, data, t_alloc, 128);
+}
+
+static void fs_readdir_split_256(void *obj, void *data,
+                                 QGuestAllocator *t_alloc)
+{
+    fs_readdir_split(obj, data, t_alloc, 256);
+}
+
+static void fs_readdir_split_512(void *obj, void *data,
+                                 QGuestAllocator *t_alloc)
+{
+    fs_readdir_split(obj, data, t_alloc, 512);
+}
+
 static void register_virtio_9p_test(void)
 {
     qos_add_test("config", "virtio-9p", pci_config, NULL);
@@ -810,6 +912,12 @@ static void register_virtio_9p_test(void)
     qos_add_test("fs/flush/ignored", "virtio-9p", fs_flush_ignored,
                  NULL);
     qos_add_test("fs/readdir/basic", "virtio-9p", fs_readdir, NULL);
+    qos_add_test("fs/readdir/split_512", "virtio-9p",
+                 fs_readdir_split_512, NULL);
+    qos_add_test("fs/readdir/split_256", "virtio-9p",
+                 fs_readdir_split_256, NULL);
+    qos_add_test("fs/readdir/split_128", "virtio-9p",
+                 fs_readdir_split_128, NULL);
 }
 
 libqos_init(register_virtio_9p_test);