[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [RFC PATCH 03/14] quorum: ignore 0-length child

From: Max Reitz
Subject: Re: [Qemu-devel] [RFC PATCH 03/14] quorum: ignore 0-length child
Date: Wed, 18 Mar 2015 08:57:12 -0400
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0

On 2015-03-18 at 01:29, Wen Congyang wrote:
On 02/24/2015 04:43 AM, Max Reitz wrote:
On 2015-02-11 at 22:07, Wen Congyang wrote:
We connect to NBD server when starting block replication, so
the length is 0 before starting block replication.

Signed-off-by: Wen Congyang <address@hidden>
Signed-off-by: zhanghailiang <address@hidden>
Signed-off-by: Gonglei <address@hidden>
   block/quorum.c | 5 +++++
   1 file changed, 5 insertions(+)

diff --git a/block/quorum.c b/block/quorum.c
index 5ed1ff8..e6aff5f 100644
--- a/block/quorum.c
+++ b/block/quorum.c
@@ -734,6 +734,11 @@ static int64_t quorum_getlength(BlockDriverState *bs)
           if (value < 0) {
               return value;
+        if (!value) {
+            continue;
+        }
           if (value != result) {
               return -EIO;
Hm, what do you think about some specific error value returned by your delayed 
NBD implementation? Like -ENOTCONN or something like that? Then we'd be able to 
discern a real 0-length block device from a not-yet-connected NBD server.
In my newest test, it cannot return -ENOTCONN, otherwise bdrv_open() will fail 
when we open the child.
Here is the backtrace:
(gdb) bt
#0  bdrv_open_common (bs=0x5555563b2230, file=0x0, options=0x5555563b55a0, 
flags=57410, drv=0x555555e90c00, errp=0x7fffffffd460) at block.c:1070
#1  0x000055555595ea72 in bdrv_open (pbs=0x7fffffffd5f8, filename=0x0, 
reference=0x0, options=0x5555563b55a0, flags=57410, drv=0x555555e90c00, 
errp=0x7fffffffd5e0) at block.c:1677
#2  0x000055555595e3a9 in bdrv_open_image (pbs=0x7fffffffd5f8, filename=0x0, 
options=0x5555563a6730, bdref_key=0x555555a86b4c "file", flags=57410, 
allow_none=true, errp=0x7fffffffd5e0) at block.c:1481
#3  0x000055555595e9ae in bdrv_open (pbs=0x555556388008, filename=0x0, 
reference=0x0, options=0x5555563a6730, flags=8258, drv=0x555555e8b800, 
errp=0x7fffffffd6b8) at block.c:1655
#4  0x00005555559b0058 in quorum_open (bs=0x55555639bd90, 
options=0x55555639f100, flags=8258, errp=0x7fffffffd758) at block/quorum.c:1000
#5  0x000055555595d0b8 in bdrv_open_common (bs=0x55555639bd90, file=0x0, 
options=0x55555639f100, flags=8258, drv=0x555555e8e5c0, errp=0x7fffffffd840) at 
#6  0x000055555595ea72 in bdrv_open (pbs=0x55555639bd50, filename=0x0, 
reference=0x0, options=0x55555639f100, flags=8258, drv=0x555555e8e5c0, 
errp=0x7fffffffdb70) at block.c:1677
#7  0x00005555559b3bd3 in blk_new_open (name=0x55555639bc60 "virtio0", 
filename=0x0, reference=0x0, options=0x55555639a420, flags=66, errp=0x7fffffffdb70) at 
#8  0x0000555555754f78 in blockdev_init (file=0x0, bs_opts=0x55555639a420, 
errp=0x7fffffffdb70) at blockdev.c:536
#9  0x0000555555755d90 in drive_new (all_opts=0x5555563777e0, 
block_default_type=IF_IDE) at blockdev.c:971
#10 0x000055555576b1f0 in drive_init_func (opts=0x5555563777e0, 
opaque=0x555556372b48) at vl.c:1104
#11 0x0000555555a1b019 in qemu_opts_foreach (list=0x555555e44060, func=0x55555576b1ba 
<drive_init_func>, opaque=0x555556372b48, abort_on_failure=1) at 
#12 0x00005555557743dd in main (argc=25, argv=0x7fffffffe0c8, 
envp=0x7fffffffe198) at vl.c:4191

refresh_total_sectors() will fail if we return -ENOTCONN.

Okay, then 0 will be fine, too.


reply via email to

[Prev in Thread] Current Thread [Next in Thread]