Re: [Qemu-devel] [PATCH V9 00/11] Quorum block driver

[Max Reitz <mreitz@redhat.com>]

[-- Attachment #1: Type: text/plain, Size: 3208 bytes --]

Am 29.10.2013 18:55, schrieb Max Reitz:
> Am 29.10.2013 08:59, schrieb Benoît Canet:
>> Le Friday 04 Oct 2013 à 16:31:56 (+0200), Max Reitz a écrit :
>>> On 2013-10-02 14:39, Benoît Canet wrote:
>>>> It must be applied on top of "block: Add BlockDriver.bdrv_check_ext_snapshot."
>>>>
>>>> This patchset create a block driver implementing a quorum using total qemu disk
>>>> images. Writes are mirrored on the $total files.
>>>> For the reading part the $total files are read at the same time and a vote is
>>>> done to determine if a qiov version is present $threshold or more times. It then
>>>> return this majority version to the upper layers.
>>>> When i < $threshold versions of the data are returned by the lower layer the
>>>> quorum is broken and the read return -EIO.
>>>>
>>>> The goal of this patchset is to be turned in a QEMU block filter living just
>>>> above raw-*.c and below qcow2/qed when the required infrastructure will be done.
>>>>
>>>> Main use of this feature will be people using NFS appliances which can be
>>>> subjected to bitflip errors.
>>>>
>>>> This patchset can be used to replace blkverify and the out of tree blkmirror.
>>>>
>>>> v9: integrate latests comments from kevin
>>>>
>>>> Benoît Canet (11):
>>>>   quorum: Create quorum.c, add QuorumSingleAIOCB and QuorumAIOCB.
>>>>   quorum: Create BDRVQuorumState and BlkDriver and do init.
>>>>   quorum: Add quorum_aio_writev and its dependencies.
>>>>   blkverify: Extract qemu_iovec_clone() and qemu_iovec_compare() from
>>>>     blkverify.
>>>>   quorum: Add quorum_aio_readv.
>>>>   quorum: Add quorum mechanism.
>>>>   quorum: Add quorum_getlength().
>>>>   quorum: Add quorum_invalidate_cache().
>>>>   quorum: Add quorum_co_get_block_status.
>>>>   quorum: Add quorum_co_flush().
>>>>   quorum: Add quorum_open() and quorum_close().
>>>>
>>>>  block/Makefile.objs       |    1 +
>>>>  block/blkverify.c         |  108 +----
>>>>  block/quorum.c            | 1035 +++++++++++++++++++++++++++++++++++++++++++++
>>>>  configure                 |   36 ++
>>>>  include/monitor/monitor.h |    2 +
>>>>  include/qemu-common.h     |    2 +
>>>>  monitor.c                 |    2 +
>>>>  util/iov.c                |  103 +++++
>>>>  8 files changed, 1183 insertions(+), 106 deletions(-)
>>>>  create mode 100644 block/quorum.c
>>>>
>>> Could you add a qemu-iotest if possible?
>> I don't see how to specify quorum to qemu-io for bytes checking.
>>
>> Best regards
>>
>> Benoît
> As of commit b543c5cd, you can pass options to the block driver through
> qemu-io -c open. The problem for quorum is that it cannot handle the
> filename option (which qemu-io will always set). I've attached a diff to
> change this behavior (which makes the path parameter for open optional
> and passes NULL to bdrv_open if it is not given). You're free to make
> use of it. ;-)
>
> If this diff is applied, you can invoke qemu-io with quorum for example
> as following:
> qemu-io -c 'open -o
> file.driver=quorum,file.children.0.file.filename=[Image
> 1],file.children.1.file.filename=[Image 2],file.vote_threshold=[x]'
>
> Max

Obviously forgot to attach the diff.

Max

[-- Attachment #2: qemu-io-open.diff --]
[-- Type: text/plain, Size: 2331 bytes --]

diff --git a/qemu-io.c b/qemu-io.c
index 3b3340a..4d0e9f6 100644
--- a/qemu-io.c
+++ b/qemu-io.c
@@ -57,8 +57,13 @@ static int openfile(char *name, int flags, int growable, QDict *opts)
 
     if (growable) {
         if (bdrv_file_open(&qemuio_bs, name, opts, flags, &local_err)) {
-            fprintf(stderr, "%s: can't open device %s: %s\n", progname, name,
-                    error_get_pretty(local_err));
+            if (name) {
+                fprintf(stderr, "%s: can't open device %s: %s\n", progname,
+                        name, error_get_pretty(local_err));
+            } else {
+                fprintf(stderr, "%s: can't open device: %s\n", progname,
+                        error_get_pretty(local_err));
+            }
             error_free(local_err);
             return 1;
         }
@@ -66,8 +71,13 @@ static int openfile(char *name, int flags, int growable, QDict *opts)
         qemuio_bs = bdrv_new("hda");
 
         if (bdrv_open(qemuio_bs, name, opts, flags, NULL, &local_err) < 0) {
-            fprintf(stderr, "%s: can't open device %s: %s\n", progname, name,
-                    error_get_pretty(local_err));
+            if (name) {
+                fprintf(stderr, "%s: can't open device %s: %s\n", progname,
+                        name, error_get_pretty(local_err));
+            } else {
+                fprintf(stderr, "%s: can't open device: %s\n", progname,
+                        error_get_pretty(local_err));
+            }
             error_free(local_err);
             bdrv_unref(qemuio_bs);
             qemuio_bs = NULL;
@@ -127,6 +137,7 @@ static int open_f(BlockDriverState *bs, int argc, char **argv)
     int c;
     QemuOpts *qopts;
     QDict *opts = NULL;
+    char *filename = NULL;
 
     while ((c = getopt(argc, argv, "snrgo:")) != EOF) {
         switch (c) {
@@ -160,11 +171,13 @@ static int open_f(BlockDriverState *bs, int argc, char **argv)
         flags |= BDRV_O_RDWR;
     }
 
-    if (optind != argc - 1) {
+    if (optind == argc - 1) {
+        filename = argv[optind];
+    } else if (optind < argc - 1) {
         return qemuio_command_usage(&open_cmd);
     }
 
-    return openfile(argv[optind], flags, growable, opts);
+    return openfile(filename, flags, growable, opts);
 }
 
 static int quit_f(BlockDriverState *bs, int argc, char **argv)