[Qemu-devel] [PULL 0/9] Block layer patches

[Qemu-devel] [PULL 0/9] Block layer patches

[Kevin Wolf]

The following changes since commit d61d1a1fb2f1db6c54651844a28389c523f3f8c7:

  Merge remote-tracking branch 'remotes/kraxel/tags/fixes-20190402-pull-request' into staging (2019-04-02 08:18:24 +0100)

are available in the Git repository at:

  git://repo.or.cz/qemu/kevin.git tags/for-upstream

for you to fetch changes up to f18957b854495129f2e8d6838df3bf47d1c1479c:

  tests/qemu-iotests/235: Allow fallback to tcg (2019-04-02 12:04:56 +0200)

----------------------------------------------------------------
Block layer patches:

- file-posix: Ignore unlock failure instead of crashing
- gluster: Limit the transfer size to 512 MiB
- stream: Fix backing chain freezing
- qemu-img: Enable BDRV_REQ_MAY_UNMAP for zero writes in convert
- iotests fixes

----------------------------------------------------------------
Alberto Garcia (3):
      block: continue until base is found in bdrv_freeze_backing_chain() et al
      block: freeze the backing chain earlier in stream_start()
      block: test block-stream with a base node that is used by block-commit

Nir Soffer (1):
      qemu-img: Enable BDRV_REQ_MAY_UNMAP in convert

Stefano Garzarella (1):
      block/gluster: limit the transfer size to 512 MiB

Thomas Huth (3):
      iotests: Fix test 200 on s390x without virtio-pci
      tests/qemu-iotests: Remove redundant COPYING file
      tests/qemu-iotests/235: Allow fallback to tcg

Vladimir Sementsov-Ogievskiy (1):
      block/file-posix: do not fail on unlock bytes

 block.c                    |  21 ++-
 block/file-posix.c         |  12 ++
 block/gluster.c            |  16 +++
 block/stream.c             |  13 +-
 qemu-img.c                 |   3 +-
 tests/qemu-iotests/030     |  17 +++
 tests/qemu-iotests/030.out |   4 +-
 tests/qemu-iotests/200     |  14 +-
 tests/qemu-iotests/235     |   2 +-
 tests/qemu-iotests/COPYING | 339 ---------------------------------------------
 10 files changed, 82 insertions(+), 359 deletions(-)
 delete mode 100644 tests/qemu-iotests/COPYING

[Qemu-devel] [PULL 1/9] iotests: Fix test 200 on s390x without virtio-pci

[Kevin Wolf]

From: Thomas Huth <thuth@redhat.com>

virtio-pci is optional on s390x, e.g. in downstream RHEL builds, it
is disabled. On s390x, virtio-ccw should be used instead. Other tests
like 051 or 240 already use virtio-scsi-ccw instead of virtio-scsi-pci
on s390x, so let's do the same here and always use virtio-scsi-ccw on
s390x.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 tests/qemu-iotests/200 | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/tests/qemu-iotests/200 b/tests/qemu-iotests/200
index 12d25f4a1c..1c0f8cafc2 100755
--- a/tests/qemu-iotests/200
+++ b/tests/qemu-iotests/200
@@ -52,13 +52,21 @@ ${QEMU_IMG} create -f $IMGFMT -F $IMGFMT "${TEST_IMG}" -b "${BACKING_IMG}" 512M
 
 ${QEMU_IO} -c "write -P 0xa5 512 300M" "${BACKING_IMG}" | _filter_qemu_io
 
+case "$QEMU_DEFAULT_MACHINE" in
+  s390-ccw-virtio)
+      virtio_scsi="-device virtio-scsi-ccw,id=scsi0,iothread=iothread0"
+      ;;
+  *)
+      virtio_scsi="-device pci-bridge,id=bridge1,chassis_nr=1,bus=pci.0
+          -device virtio-scsi-pci,bus=bridge1,addr=0x1f,id=scsi0,iothread=iothread0"
+      ;;
+esac
+
 echo
 echo === Starting QEMU VM ===
 echo
 qemu_comm_method="qmp"
-_launch_qemu -device pci-bridge,id=bridge1,chassis_nr=1,bus=pci.0 \
-             -object iothread,id=iothread0 \
-             -device virtio-scsi-pci,bus=bridge1,addr=0x1f,id=scsi0,iothread=iothread0 \
+_launch_qemu -object iothread,id=iothread0 $virtio_scsi \
              -drive file="${TEST_IMG}",media=disk,if=none,cache=$CACHEMODE,id=drive_sysdisk,format=$IMGFMT \
              -device scsi-hd,drive=drive_sysdisk,bus=scsi0.0,id=sysdisk,bootindex=0
 h1=$QEMU_HANDLE
-- 
2.20.1

[Qemu-devel] [PULL 2/9] qemu-img: Enable BDRV_REQ_MAY_UNMAP in convert

[Kevin Wolf]

From: Nir Soffer <nirsof@gmail.com>

With Kevin's "block: Fix slow pre-zeroing in qemu-img convert"[1]
(commit c9fdcf202f, 'qemu-img: Use BDRV_REQ_NO_FALLBACK for
pre-zeroing') we skip the pre zero step called like this:

    blk_make_zero(s->target, BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK)

And we write zeroes later using:

    blk_co_pwrite_zeroes(s->target,
                         sector_num << BDRV_SECTOR_BITS,
                         n << BDRV_SECTOR_BITS, 0);

Since we use flags=0, this is translated to NBD_CMD_WRITE_ZEROES with
NBD_CMD_FLAG_NO_HOLE flag, which cause the NBD server to allocated space
instead of punching a hole.

Here is an example failure:

$ dd if=/dev/urandom of=src.img bs=1M count=5
$ truncate -s 50m src.img
$ truncate -s 50m dst.img
$ nbdkit -f -v -e '' -U nbd.sock file file=dst.img

$ ./qemu-img convert -n src.img nbd:unix:nbd.sock

We can see in nbdkit log that it received the NBD_CMD_FLAG_NO_HOLE
(may_trim=0):

nbdkit: file[1]: debug: newstyle negotiation: flags: export 0x4d
nbdkit: file[1]: debug: pwrite count=2097152 offset=0
nbdkit: file[1]: debug: pwrite count=2097152 offset=2097152
nbdkit: file[1]: debug: pwrite count=1048576 offset=4194304
nbdkit: file[1]: debug: zero count=33554432 offset=5242880 may_trim=0
nbdkit: file[1]: debug: zero count=13631488 offset=38797312 may_trim=0
nbdkit: file[1]: debug: flush

And the image became fully allocated:

$ qemu-img info dst.img
virtual size: 50M (52428800 bytes)
disk size: 50M

With this change we see that nbdkit did not receive the
NBD_CMD_FLAG_NO_HOLE (may_trim=1):

nbdkit: file[1]: debug: newstyle negotiation: flags: export 0x4d
nbdkit: file[1]: debug: pwrite count=2097152 offset=0
nbdkit: file[1]: debug: pwrite count=2097152 offset=2097152
nbdkit: file[1]: debug: pwrite count=1048576 offset=4194304
nbdkit: file[1]: debug: zero count=33554432 offset=5242880 may_trim=1
nbdkit: file[1]: debug: zero count=13631488 offset=38797312 may_trim=1
nbdkit: file[1]: debug: flush

And the file is sparse as expected:

$ qemu-img info dst.img
virtual size: 50M (52428800 bytes)
disk size: 5.0M

[1] http://lists.nongnu.org/archive/html/qemu-block/2019-03/msg00761.html

Signed-off-by: Nir Soffer <nsoffer@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 qemu-img.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/qemu-img.c b/qemu-img.c
index 76a961df82..aa6f81f1ea 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1756,7 +1756,8 @@ static int coroutine_fn convert_co_write(ImgConvertState *s, int64_t sector_num,
             }
             ret = blk_co_pwrite_zeroes(s->target,
                                        sector_num << BDRV_SECTOR_BITS,
-                                       n << BDRV_SECTOR_BITS, 0);
+                                       n << BDRV_SECTOR_BITS,
+                                       BDRV_REQ_MAY_UNMAP);
             if (ret < 0) {
                 return ret;
             }
-- 
2.20.1

[Qemu-devel] [PULL 3/9] block/gluster: limit the transfer size to 512 MiB

[Kevin Wolf]

From: Stefano Garzarella <sgarzare@redhat.com>

Several versions of GlusterFS (3.12? -> 6.0.1) fail when the
transfer size is greater or equal to 1024 MiB, so we are
limiting the transfer size to 512 MiB to avoid this rare issue.

Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1691320
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Niels de Vos <ndevos@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/gluster.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/block/gluster.c b/block/gluster.c
index 51f184cbd8..e664ca4462 100644
--- a/block/gluster.c
+++ b/block/gluster.c
@@ -9,6 +9,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/units.h"
 #include <glusterfs/api/glfs.h>
 #include "block/block_int.h"
 #include "block/qdict.h"
@@ -41,6 +42,12 @@
 #define GLUSTER_DEBUG_MAX           9
 #define GLUSTER_OPT_LOGFILE         "logfile"
 #define GLUSTER_LOGFILE_DEFAULT     "-" /* handled in libgfapi as /dev/stderr */
+/*
+ * Several versions of GlusterFS (3.12? -> 6.0.1) fail when the transfer size
+ * is greater or equal to 1024 MiB, so we are limiting the transfer size to 512
+ * MiB to avoid this rare issue.
+ */
+#define GLUSTER_MAX_TRANSFER        (512 * MiB)
 
 #define GERR_INDEX_HINT "hint: check in 'server' array index '%d'\n"
 
@@ -887,6 +894,11 @@ out:
     return ret;
 }
 
+static void qemu_gluster_refresh_limits(BlockDriverState *bs, Error **errp)
+{
+    bs->bl.max_transfer = GLUSTER_MAX_TRANSFER;
+}
+
 static int qemu_gluster_reopen_prepare(BDRVReopenState *state,
                                        BlockReopenQueue *queue, Error **errp)
 {
@@ -1544,6 +1556,7 @@ static BlockDriver bdrv_gluster = {
     .bdrv_co_pwrite_zeroes        = qemu_gluster_co_pwrite_zeroes,
 #endif
     .bdrv_co_block_status         = qemu_gluster_co_block_status,
+    .bdrv_refresh_limits          = qemu_gluster_refresh_limits,
     .create_opts                  = &qemu_gluster_create_opts,
     .strong_runtime_opts          = gluster_strong_open_opts,
 };
@@ -1574,6 +1587,7 @@ static BlockDriver bdrv_gluster_tcp = {
     .bdrv_co_pwrite_zeroes        = qemu_gluster_co_pwrite_zeroes,
 #endif
     .bdrv_co_block_status         = qemu_gluster_co_block_status,
+    .bdrv_refresh_limits          = qemu_gluster_refresh_limits,
     .create_opts                  = &qemu_gluster_create_opts,
     .strong_runtime_opts          = gluster_strong_open_opts,
 };
@@ -1604,6 +1618,7 @@ static BlockDriver bdrv_gluster_unix = {
     .bdrv_co_pwrite_zeroes        = qemu_gluster_co_pwrite_zeroes,
 #endif
     .bdrv_co_block_status         = qemu_gluster_co_block_status,
+    .bdrv_refresh_limits          = qemu_gluster_refresh_limits,
     .create_opts                  = &qemu_gluster_create_opts,
     .strong_runtime_opts          = gluster_strong_open_opts,
 };
@@ -1640,6 +1655,7 @@ static BlockDriver bdrv_gluster_rdma = {
     .bdrv_co_pwrite_zeroes        = qemu_gluster_co_pwrite_zeroes,
 #endif
     .bdrv_co_block_status         = qemu_gluster_co_block_status,
+    .bdrv_refresh_limits          = qemu_gluster_refresh_limits,
     .create_opts                  = &qemu_gluster_create_opts,
     .strong_runtime_opts          = gluster_strong_open_opts,
 };
-- 
2.20.1

[Qemu-devel] [PULL 4/9] tests/qemu-iotests: Remove redundant COPYING file

[Kevin Wolf]

From: Thomas Huth <thuth@redhat.com>

The file tests/qemu-iotests/COPYING is the same text as in the
COPYING file in the main directory. So as far as I can see, we don't
need the duplicate here.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 tests/qemu-iotests/COPYING | 339 -------------------------------------
 1 file changed, 339 deletions(-)
 delete mode 100644 tests/qemu-iotests/COPYING

diff --git a/tests/qemu-iotests/COPYING b/tests/qemu-iotests/COPYING
deleted file mode 100644
index 00ccfbb628..0000000000
--- a/tests/qemu-iotests/COPYING
+++ /dev/null
@@ -1,339 +0,0 @@
-		    GNU GENERAL PUBLIC LICENSE
-		       Version 2, June 1991
-
- Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
- 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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-TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
-YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
-PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
-POSSIBILITY OF SUCH DAMAGES.
-
-		     END OF TERMS AND CONDITIONS
-\f
-	    How to Apply These Terms to Your New Programs
-
-  If you develop a new program, and you want it to be of the greatest
-possible use to the public, the best way to achieve this is to make it
-free software which everyone can redistribute and change under these terms.
-
-  To do so, attach the following notices to the program.  It is safest
-to attach them to the start of each source file to most effectively
-convey the exclusion of warranty; and each file should have at least
-the "copyright" line and a pointer to where the full notice is found.
-
-    <one line to give the program's name and a brief idea of what it does.>
-    Copyright (C) <year>  <name of author>
-
-    This program is free software; you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation; either version 2 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-
-    You should have received a copy of the GNU General Public License along
-    with this program; if not, write to the Free Software Foundation, Inc.,
-    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
-
-Also add information on how to contact you by electronic and paper mail.
-
-If the program is interactive, make it output a short notice like this
-when it starts in an interactive mode:
-
-    Gnomovision version 69, Copyright (C) year name of author
-    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
-    This is free software, and you are welcome to redistribute it
-    under certain conditions; type `show c' for details.
-
-The hypothetical commands `show w' and `show c' should show the appropriate
-parts of the General Public License.  Of course, the commands you use may
-be called something other than `show w' and `show c'; they could even be
-mouse-clicks or menu items--whatever suits your program.
-
-You should also get your employer (if you work as a programmer) or your
-school, if any, to sign a "copyright disclaimer" for the program, if
-necessary.  Here is a sample; alter the names:
-
-  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
-  `Gnomovision' (which makes passes at compilers) written by James Hacker.
-
-  <signature of Ty Coon>, 1 April 1989
-  Ty Coon, President of Vice
-
-This General Public License does not permit incorporating your program into
-proprietary programs.  If your program is a subroutine library, you may
-consider it more useful to permit linking proprietary applications with the
-library.  If this is what you want to do, use the GNU Lesser General
-Public License instead of this License.
-- 
2.20.1

[Qemu-devel] [PULL 5/9] block/file-posix: do not fail on unlock bytes

[Kevin Wolf]

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

bdrv_replace_child() calls bdrv_check_perm() with error_abort on
loosening permissions. However file-locking operations may fail even
in this case, for example on NFS. And this leads to Qemu crash.

Let's avoid such errors. Note, that we ignore such things anyway on
permission update commit and abort.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/file-posix.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/block/file-posix.c b/block/file-posix.c
index db4cccbe51..1cf4ee49eb 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -815,6 +815,18 @@ static int raw_handle_perm_lock(BlockDriverState *bs,
 
     switch (op) {
     case RAW_PL_PREPARE:
+        if ((s->perm | new_perm) == s->perm &&
+            (s->shared_perm & new_shared) == s->shared_perm)
+        {
+            /*
+             * We are going to unlock bytes, it should not fail. If it fail due
+             * to some fs-dependent permission-unrelated reasons (which occurs
+             * sometimes on NFS and leads to abort in bdrv_replace_child) we
+             * can't prevent such errors by any check here. And we ignore them
+             * anyway in ABORT and COMMIT.
+             */
+            return 0;
+        }
         ret = raw_apply_lock_bytes(s, s->fd, s->perm | new_perm,
                                    ~s->shared_perm | ~new_shared,
                                    false, errp);
-- 
2.20.1

[Qemu-devel] [PULL 6/9] block: continue until base is found in bdrv_freeze_backing_chain() et al

[Kevin Wolf]

From: Alberto Garcia <berto@igalia.com>

All three functions that handle the BdrvChild.frozen attribute walk
the backing chain from 'bs' to 'base' and stop either when 'base' is
found or at the end of the chain if 'base' is NULL.

However if 'base' is not found then the functions return without
errors as if it was NULL.

This is wrong: if the caller passed an incorrect parameter that means
that there is a bug in the code.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/block.c b/block.c
index 0a93ee9ac8..3050854528 100644
--- a/block.c
+++ b/block.c
@@ -4218,14 +4218,15 @@ BlockDriverState *bdrv_find_base(BlockDriverState *bs)
 /*
  * Return true if at least one of the backing links between @bs and
  * @base is frozen. @errp is set if that's the case.
+ * @base must be reachable from @bs, or NULL.
  */
 bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base,
                                   Error **errp)
 {
     BlockDriverState *i;
 
-    for (i = bs; i != base && i->backing; i = backing_bs(i)) {
-        if (i->backing->frozen) {
+    for (i = bs; i != base; i = backing_bs(i)) {
+        if (i->backing && i->backing->frozen) {
             error_setg(errp, "Cannot change '%s' link from '%s' to '%s'",
                        i->backing->name, i->node_name,
                        backing_bs(i)->node_name);
@@ -4240,6 +4241,7 @@ bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base,
  * Freeze all backing links between @bs and @base.
  * If any of the links is already frozen the operation is aborted and
  * none of the links are modified.
+ * @base must be reachable from @bs, or NULL.
  * Returns 0 on success. On failure returns < 0 and sets @errp.
  */
 int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base,
@@ -4251,8 +4253,10 @@ int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base,
         return -EPERM;
     }
 
-    for (i = bs; i != base && i->backing; i = backing_bs(i)) {
-        i->backing->frozen = true;
+    for (i = bs; i != base; i = backing_bs(i)) {
+        if (i->backing) {
+            i->backing->frozen = true;
+        }
     }
 
     return 0;
@@ -4261,14 +4265,17 @@ int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base,
 /*
  * Unfreeze all backing links between @bs and @base. The caller must
  * ensure that all links are frozen before using this function.
+ * @base must be reachable from @bs, or NULL.
  */
 void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base)
 {
     BlockDriverState *i;
 
-    for (i = bs; i != base && i->backing; i = backing_bs(i)) {
-        assert(i->backing->frozen);
-        i->backing->frozen = false;
+    for (i = bs; i != base; i = backing_bs(i)) {
+        if (i->backing) {
+            assert(i->backing->frozen);
+            i->backing->frozen = false;
+        }
     }
 }
 
-- 
2.20.1

[Qemu-devel] [PULL 7/9] block: freeze the backing chain earlier in stream_start()

[Kevin Wolf]

From: Alberto Garcia <berto@igalia.com>

Commit 6585493369819a48d34a86d57ec6b97cb5cd9bc0 added code to freeze
the backing chain from 'top' to 'base' for the duration of the
block-stream job.

The problem is that the freezing happens too late in stream_start():
during the bdrv_reopen_set_read_only() call earlier in that function
another job can jump in and remove the base image. If that happens we
have an invalid chain and QEMU crashes.

This patch puts the bdrv_freeze_backing_chain() call at the beginning
of the function.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/stream.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/block/stream.c b/block/stream.c
index 6253c86fae..bfaebb861a 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -238,11 +238,16 @@ void stream_start(const char *job_id, BlockDriverState *bs,
     BlockDriverState *iter;
     bool bs_read_only;
 
+    if (bdrv_freeze_backing_chain(bs, base, errp) < 0) {
+        return;
+    }
+
     /* Make sure that the image is opened in read-write mode */
     bs_read_only = bdrv_is_read_only(bs);
     if (bs_read_only) {
         if (bdrv_reopen_set_read_only(bs, false, errp) != 0) {
-            return;
+            bs_read_only = false;
+            goto fail;
         }
     }
 
@@ -269,11 +274,6 @@ void stream_start(const char *job_id, BlockDriverState *bs,
                            &error_abort);
     }
 
-    if (bdrv_freeze_backing_chain(bs, base, errp) < 0) {
-        job_early_fail(&s->common.job);
-        goto fail;
-    }
-
     s->base = base;
     s->backing_file_str = g_strdup(backing_file_str);
     s->bs_read_only = bs_read_only;
@@ -288,4 +288,5 @@ fail:
     if (bs_read_only) {
         bdrv_reopen_set_read_only(bs, true, NULL);
     }
+    bdrv_unfreeze_backing_chain(bs, base);
 }
-- 
2.20.1

[Qemu-devel] [PULL 8/9] block: test block-stream with a base node that is used by block-commit

[Kevin Wolf]

From: Alberto Garcia <berto@igalia.com>

The base node of a block-stream operation indicates the first image
from the backing chain starting from which no data is copied to the
top node.

The block-stream job allows others to use that base image, so a second
block-stream job could be writing to it at the same time. An important
restriction is that the base image must not disappear while the stream
job is ongoing. stream_start() freezes the backing chain from top to
base with that purpose but it does it too late in the code so there is
a race condition there.

This bug was fixed in the previous commit, and this patch contains an
iotest for this scenario.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 tests/qemu-iotests/030     | 17 +++++++++++++++++
 tests/qemu-iotests/030.out |  4 ++--
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/tests/qemu-iotests/030 b/tests/qemu-iotests/030
index 276e06b5ba..c6311d1825 100755
--- a/tests/qemu-iotests/030
+++ b/tests/qemu-iotests/030
@@ -314,6 +314,23 @@ class TestParallelOps(iotests.QMPTestCase):
 
         self.wait_until_completed(drive='commit-drive0')
 
+    # In this case the base node of the stream job is the same as the
+    # top node of commit job. Since block-commit removes the top node
+    # when it finishes, this is not allowed.
+    def test_overlapping_4(self):
+        self.assert_no_active_block_jobs()
+
+        # Commit from node2 into node0
+        result = self.vm.qmp('block-commit', device='drive0', top=self.imgs[2], base=self.imgs[0])
+        self.assert_qmp(result, 'return', {})
+
+        # Stream from node2 into node4
+        result = self.vm.qmp('block-stream', device='node4', base_node='node2', job_id='node4')
+        self.assert_qmp(result, 'error/class', 'GenericError')
+
+        self.wait_until_completed()
+        self.assert_no_active_block_jobs()
+
     # Test a block-stream and a block-commit job in parallel
     # Here the stream job is supposed to finish quickly in order to reproduce
     # the scenario that triggers the bug fixed in 3d5d319e1221 and 1a63a907507
diff --git a/tests/qemu-iotests/030.out b/tests/qemu-iotests/030.out
index 42314e9c00..4fd1c2dcd2 100644
--- a/tests/qemu-iotests/030.out
+++ b/tests/qemu-iotests/030.out
@@ -1,5 +1,5 @@
-........................
+.........................
 ----------------------------------------------------------------------
-Ran 24 tests
+Ran 25 tests
 
 OK
-- 
2.20.1

[Qemu-devel] [PULL 9/9] tests/qemu-iotests/235: Allow fallback to tcg

[Kevin Wolf]

From: Thomas Huth <thuth@redhat.com>

iotest 235 currently only works with KVM - this is bad for systems where
it is not available, e.g. CI pipelines. The test also works when using
"tcg" as accelerator, so we can simply add that to the list of accelerators,
too.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 tests/qemu-iotests/235 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/qemu-iotests/235 b/tests/qemu-iotests/235
index 75c203b30c..2b6a8c13be 100755
--- a/tests/qemu-iotests/235
+++ b/tests/qemu-iotests/235
@@ -49,7 +49,7 @@ qemu_img_create('-f', iotests.imgfmt, '-o', 'preallocation=metadata', disk,
                 str(size))
 
 vm = QEMUMachine(iotests.qemu_prog)
-vm.add_args('-machine', 'accel=kvm')
+vm.add_args('-machine', 'accel=kvm:tcg')
 if iotests.qemu_default_machine == 's390-ccw-virtio':
         vm.add_args('-no-shutdown')
 vm.add_args('-drive', 'id=src,file=' + disk)
-- 
2.20.1

Re: [Qemu-devel] [PULL 0/9] Block layer patches

[Peter Maydell]

On Tue, 2 Apr 2019 at 19:49, Kevin Wolf <kwolf@redhat.com> wrote:
>
> The following changes since commit d61d1a1fb2f1db6c54651844a28389c523f3f8c7:
>
>   Merge remote-tracking branch 'remotes/kraxel/tags/fixes-20190402-pull-request' into staging (2019-04-02 08:18:24 +0100)
>
> are available in the Git repository at:
>
>   git://repo.or.cz/qemu/kevin.git tags/for-upstream
>
> for you to fetch changes up to f18957b854495129f2e8d6838df3bf47d1c1479c:
>
>   tests/qemu-iotests/235: Allow fallback to tcg (2019-04-02 12:04:56 +0200)
>
> ----------------------------------------------------------------
> Block layer patches:
>
> - file-posix: Ignore unlock failure instead of crashing
> - gluster: Limit the transfer size to 512 MiB
> - stream: Fix backing chain freezing
> - qemu-img: Enable BDRV_REQ_MAY_UNMAP for zero writes in convert
> - iotests fixes

Applied, thanks.

Please update the changelog at https://wiki.qemu.org/ChangeLog/4.0
for any user-visible changes.

-- PMM