From a7e7af18d64164fac42581452f6dc3c07650fcae Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Fri, 30 Jul 2021 10:19:57 +0100
Subject: [PATCH] delay: Add delay-open and delay-close

Useful for simulating VDDK which has very slow connection.

(cherry picked from commit de8dcd3a34a38b088a0f9a6f8ca754702ad1f598)
---
 filters/delay/delay.c                 | 58 ++++++++++++++++++++++++++-
 filters/delay/nbdkit-delay-filter.pod | 27 +++++++++++--
 2 files changed, 80 insertions(+), 5 deletions(-)

diff --git a/filters/delay/delay.c b/filters/delay/delay.c
index 5a925aa4..df3729a7 100644
--- a/filters/delay/delay.c
+++ b/filters/delay/delay.c
@@ -48,6 +48,8 @@ static unsigned delay_zero_ms = 0;   /* zero delay (milliseconds) */
 static unsigned delay_trim_ms = 0;   /* trim delay (milliseconds) */
 static unsigned delay_extents_ms = 0;/* extents delay (milliseconds) */
 static unsigned delay_cache_ms = 0;  /* cache delay (milliseconds) */
+static unsigned delay_open_ms = 0;   /* open delay (milliseconds) */
+static unsigned delay_close_ms = 0;  /* close delay (milliseconds) */
 
 static int delay_fast_zero = 1; /* whether delaying zero includes fast zero */
 
@@ -126,6 +128,18 @@ cache_delay (int *err)
   return delay (delay_cache_ms, err);
 }
 
+static int
+open_delay (int *err)
+{
+  return delay (delay_open_ms, err);
+}
+
+static int
+close_delay (int *err)
+{
+  return delay (delay_close_ms, err);
+}
+
 /* Called for each key=value passed on the command line. */
 static int
 delay_config (nbdkit_next_config *next, nbdkit_backend *nxdata,
@@ -182,6 +196,16 @@ delay_config (nbdkit_next_config *next, nbdkit_backend *nxdata,
       return -1;
     return 0;
   }
+  else if (strcmp (key, "delay-open") == 0) {
+    if (parse_delay (key, value, &delay_open_ms) == -1)
+      return -1;
+    return 0;
+  }
+  else if (strcmp (key, "delay-close") == 0) {
+    if (parse_delay (key, value, &delay_close_ms) == -1)
+      return -1;
+    return 0;
+  }
   else
     return next (nxdata, key, value);
 }
@@ -195,7 +219,9 @@ delay_config (nbdkit_next_config *next, nbdkit_backend *nxdata,
   "delay-extents=<NN>[ms]         Extents delay in seconds/milliseconds.\n" \
   "delay-cache=<NN>[ms]           Cache delay in seconds/milliseconds.\n" \
   "wdelay=<NN>[ms]                Write, zero and trim delay in secs/msecs.\n" \
-  "delay-fast-zero=<BOOL>         Delay fast zero requests (default true).\n"
+  "delay-fast-zero=<BOOL>         Delay fast zero requests (default true).\n" \
+  "delay-open=<NN>[ms]            Open delay in seconds/milliseconds.\n" \
+  "delay-close=<NN>[ms]           Close delay in seconds/milliseconds."
 
 /* Override the plugin's .can_fast_zero if needed */
 static int
@@ -208,6 +234,34 @@ delay_can_fast_zero (nbdkit_next *next,
   return next->can_fast_zero (next);
 }
 
+/* Open connection. */
+static void *
+delay_open (nbdkit_next_open *next, nbdkit_context *nxdata,
+            int readonly, const char *exportname, int is_tls)
+{
+  int err;
+
+  if (open_delay (&err) == -1) {
+    errno = err;
+    nbdkit_error ("delay: %m");
+    return NULL;
+  }
+
+  if (next (nxdata, readonly, exportname) == -1)
+    return NULL;
+
+  return NBDKIT_HANDLE_NOT_NEEDED;
+}
+
+/* Close connection. */
+static void
+delay_close (void *handle)
+{
+  int err;
+
+  close_delay (&err);
+}
+
 /* Read data. */
 static int
 delay_pread (nbdkit_next *next,
@@ -285,6 +339,8 @@ static struct nbdkit_filter filter = {
   .config            = delay_config,
   .config_help       = delay_config_help,
   .can_fast_zero     = delay_can_fast_zero,
+  .open              = delay_open,
+  .close             = delay_close,
   .pread             = delay_pread,
   .pwrite            = delay_pwrite,
   .zero              = delay_zero,
diff --git a/filters/delay/nbdkit-delay-filter.pod b/filters/delay/nbdkit-delay-filter.pod
index d6961a9e..11ae544b 100644
--- a/filters/delay/nbdkit-delay-filter.pod
+++ b/filters/delay/nbdkit-delay-filter.pod
@@ -9,10 +9,15 @@ nbdkit-delay-filter - nbdkit delay filter
  nbdkit --filter=delay plugin rdelay=NNms wdelay=NNms [plugin-args...]
 
  nbdkit --filter=delay plugin [plugin-args ...]
-          delay-read=(SECS|NNms) delay-write=(SECS|NNms)
-          delay-zero=(SECS|NNms) delay-trim=(SECS|NNms)
-          delay-extents=(SECS|NNms) delay-cache=(SECS|NNms)
+          delay-read=(SECS|NNms)
+          delay-write=(SECS|NNms)
+          delay-zero=(SECS|NNms)
+          delay-trim=(SECS|NNms)
+          delay-extents=(SECS|NNms)
+          delay-cache=(SECS|NNms)
           delay-fast-zero=BOOL
+          delay-open=(SECS|NNms)
+          delay-close=(SECS|NNms)
 
 =head1 DESCRIPTION
 
@@ -108,6 +113,20 @@ delay as any other zero request; but setting this parameter to false
 instantly fails a fast zero response without waiting for or consulting
 the plugin.
 
+=item B<delay-open=>SECS
+
+=item B<delay-open=>NNB<ms>
+
+=item B<delay-close=>SECS
+
+=item B<delay-close=>NNB<ms>
+
+(nbdkit E<ge> 1.28)
+
+Delay open and close operations by C<SECS> seconds or C<NN>
+milliseconds.  Open corresponds to client connection.  Close may not
+be visible to clients if they abruptly disconnect.
+
 =back
 
 =head1 FILES
@@ -140,4 +159,4 @@ Richard W.M. Jones
 
 =head1 COPYRIGHT
 
-Copyright (C) 2018 Red Hat Inc.
+Copyright (C) 2018-2021 Red Hat Inc.
-- 
2.31.1