From fb3ad956dce7a426329f4b3ff9354fd4e8949d75 Mon Sep 17 00:00:00 2001
From: Uri Lublin <uril@redhat.com>
Date: Mon, 30 Mar 2009 23:15:52 +0300
Subject: [PATCH 11/12] block: set high watermark and get a notification when reached

Added a monitor command block_set_watermark.
Keeping watermark in bs structure.
The user gets one notification per request.
For additional notification the user must set a new watermark.

In this patch only qcow2 format actually check the watermark
and send notifications.

Signed-off-by: Uri Lublin <uril@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Bugzilla: 489964
RH-Upstream-status: pending
Acked-by: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: john cooper <john.cooper@redhat.com>
---
 qemu/block-qcow2.c |    9 +++++++++
 qemu/block.c       |    7 +++++++
 qemu/block.h       |    2 ++
 qemu/block_int.h   |    3 +++
 qemu/monitor.c     |   21 +++++++++++++++++++++
 5 files changed, 42 insertions(+), 0 deletions(-)

diff --git a/qemu/block-qcow2.c b/qemu/block-qcow2.c
index 8ef4f1b..41750ed 100644
--- a/qemu/block-qcow2.c
+++ b/qemu/block-qcow2.c
@@ -2378,6 +2378,15 @@ retry:
 
     if (s->highest_alloc < s->free_cluster_index) {
         s->highest_alloc = s->free_cluster_index;
+        if (bs->high_watermark) {
+            uint64_t ha = (s->highest_alloc << s->cluster_bits);
+            if (ha >= bs->high_watermark) {
+                term_printf("high watermark reached for %s alloc=%" PRIu64
+                            " mark=%" PRIu64 "\n",
+                            bs->device_name, ha, bs->high_watermark);
+                bs->high_watermark = 0;
+            }
+        }
     }
 
     return (s->free_cluster_index - nb_clusters) << s->cluster_bits;
diff --git a/qemu/block.c b/qemu/block.c
index 106270c..c847088 100644
--- a/qemu/block.c
+++ b/qemu/block.c
@@ -1116,6 +1116,13 @@ void bdrv_flush_all(void)
             bdrv_flush(bs);
 }
 
+
+void bdrv_set_high_watermark(BlockDriverState *bs, uint64_t offset)
+{
+    bs->high_watermark = offset;
+}
+
+
 /*
  * Returns true iff the specified sector is present in the disk image. Drivers
  * not implementing the functionality are assumed to not support backing files,
diff --git a/qemu/block.h b/qemu/block.h
index d74f388..c3798bd 100644
--- a/qemu/block.h
+++ b/qemu/block.h
@@ -104,6 +104,8 @@ int qemu_key_check(BlockDriverState *bs, const char *name);
 void bdrv_flush(BlockDriverState *bs);
 void bdrv_flush_all(void);
 
+void bdrv_set_high_watermark(BlockDriverState *bs, uint64_t offset);
+
 int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
 	int *pnum);
 
diff --git a/qemu/block_int.h b/qemu/block_int.h
index a4629ef..9541b2e 100644
--- a/qemu/block_int.h
+++ b/qemu/block_int.h
@@ -123,6 +123,9 @@ struct BlockDriverState {
 
     void *sync_aiocb;
 
+    /* high watermark -- notify if it was reached */
+    uint64_t high_watermark;
+
     /* I/O stats (display with "info blockstats"). */
     uint64_t rd_bytes;
     uint64_t wr_bytes;
diff --git a/qemu/monitor.c b/qemu/monitor.c
index 7022744..d8296ab 100644
--- a/qemu/monitor.c
+++ b/qemu/monitor.c
@@ -595,6 +595,24 @@ static void do_gdbserver(const char *port)
 }
 #endif
 
+void do_block_set_watermark(char *device, int megs)
+{
+    uint64_t offset = ((uint64_t)megs) << 20;
+    BlockDriverState *bs;
+
+    bs = bdrv_find(device);
+    if (!bs) {
+        term_printf("device not found\n");
+        return;
+    }
+
+    if (megs < 0)
+        term_printf("ileggal offset\n");
+    else
+        bdrv_set_high_watermark(bs, offset);
+}
+
+
 static void term_printc(int c)
 {
     term_printf("'");
@@ -1623,6 +1641,9 @@ static term_cmd_t term_cmds[] = {
 #endif
     { "notify", "ss", do_notify_async_events,
       "vnc|rtc|migration|reboot|shutdown|vmstop on|off", "enable / disable printing of notifications for the specified event" },
+    { "block_set_watermark", "Bi", do_block_set_watermark,
+      "block-device offset(in MB)",
+      "set watermark, get notification when reached"},
     { NULL, NULL, },
 };
 
-- 
1.6.1