Skip to content

Q
Qemu

mirror_resources / Qemu
12 个月 前同步成功

通知 4
Star 0
Fork 0
Q
Qemu

体验新版 GitCode，发现更多精彩内容 >>

切换分支/标签
  1. 13 3月, 2019 11 次提交
    • K
      file-posix: Make auto-read-only dynamic · 23dece19
      由 Kevin Wolf 提交于 
      Until now, with auto-read-only=on we tried to open the file read-write
first and if that failed, read-only was tried. This is actually not good
enough for libvirt, which gives QEMU SELinux permissions for read-write
only as soon as it actually intends to write to the image. So we need to
be able to switch between read-only and read-write at runtime.

This patch makes auto-read-only dynamic, i.e. the file is opened
read-only as long as no user of the node has requested write
permissions, but it is automatically reopened read-write as soon as the
first writer is attached. Conversely, if the last writer goes away, the
file is reopened read-only again.

bs->read_only is no longer set for auto-read-only=on files even if the
file descriptor is opened read-only because it will be transparently
upgraded as soon as a writer is attached. This changes the output of
qemu-iotests 232.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
      23dece19
    • K
      file-posix: Prepare permission code for fd switching · 6ceabe6f
      由 Kevin Wolf 提交于 
      In order to be able to dynamically reopen the file read-only or
read-write, depending on the users that are attached, we need to be able
to switch to a different file descriptor during the permission change.

This interacts with reopen, which also creates a new file descriptor and
performs permission changes internally. In this case, the permission
change code must reuse the reopen file descriptor instead of creating a
third one.

In turn, reopen can drop its code to copy file locks to the new file
descriptor because that is now done when applying the new permissions.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
      6ceabe6f
    • K
      file-posix: Lock new fd in raw_reopen_prepare() · a6aeca0c
      由 Kevin Wolf 提交于 
      There is no reason why we can take locks on the new file descriptor only
in raw_reopen_commit() where error handling isn't possible any more.
Instead, we can already do this in raw_reopen_prepare().
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
      a6aeca0c
    • K
      file-posix: Store BDRVRawState.reopen_state during reopen · e0c9cf3a
      由 Kevin Wolf 提交于 
      We'll want to access the file descriptor in the reopen_state while
processing permission changes in the context of the repoen.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
      e0c9cf3a
    • K
      file-posix: Factor out raw_reconfigure_getfd() · 5cec2870
      由 Kevin Wolf 提交于 
      Signed-off-by: NKevin Wolf <kwolf@redhat.com>
      5cec2870
    • K
      file-posix: Fix bdrv_open_flags() for snapshot=on · 30855137
      由 Kevin Wolf 提交于 
      Using a different read-only setting for bs->open_flags than for the
flags to the driver's open function is just inconsistent and a bad idea.
After this patch, the temporary snapshot keeps being opened read-only if
read-only=on,snapshot=on is passed.

If we wanted to change this behaviour to make only the orginal image
file read-only, but the temporary overlay read-write (as the comment in
the removed code suggests), that change would have to be made in
bdrv_temp_snapshot_options() (where the comment suggests otherwise).

Addressing this inconsistency before introducing dynamic auto-read-only
is important because otherwise we would immediately try to reopen the
temporary overlay even though the file is already unlinked.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
      30855137
    • K
      block: Make permission changes in reopen less wrong · 69b736e7
      由 Kevin Wolf 提交于 
      The way that reopen interacts with permission changes has one big
problem: Both operations are recursive, and the permissions are changes
for each node in the reopen queue.

For a simple graph that consists just of parent and child,
.bdrv_check_perm will be called twice for the child, once recursively
when adjusting the permissions of parent, and once again when the child
itself is reopened.

Even worse, the first .bdrv_check_perm call happens before
.bdrv_reopen_prepare was called for the child and the second one is
called afterwards.

Making sure that .bdrv_check_perm (and the other permission callbacks)
are called only once is hard. We can cope with multiple calls right now,
but as soon as file-posix gets a dynamic auto-read-only that may need to
open a new file descriptor, we get the additional requirement that all
of them are after the .bdrv_reopen_prepare call.

So reorder things in bdrv_reopen_multiple() to first call
.bdrv_reopen_prepare for all involved nodes and only then adjust
permissions.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
      69b736e7
    • K
      block: Avoid useless local_err · a4615ab3
      由 Kevin Wolf 提交于 
      Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NAlberto Garcia <berto@igalia.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
      a4615ab3
    • K
      qemu-iotests: commit to backing file with auto-read-only · 12efe428
      由 Kevin Wolf 提交于 
      Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
      12efe428
    • K
      tests/virtio-blk-test: Disable auto-read-only · 70304118
      由 Kevin Wolf 提交于 
      tests/virtio-blk-test uses a temporary image file that it deletes while
QEMU is still running, so it can't be reopened when writers are
attached or detached. Disable auto-read-only to keep it always writable.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
      70304118
    • V
      qapi: drop x- from x-block-latency-histogram-set · cb8aac37
      由 Vladimir Sementsov-Ogievskiy 提交于 
      Drop x- and x_ prefixes for latency histograms and update version to
4.0
Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
      cb8aac37
  3. 12 3月, 2019 29 次提交