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  1. 29 5月, 2016 1 次提交
  3. 23 5月, 2016 1 次提交
  5. 12 5月, 2016 3 次提交
    • E
      block: Honor BDRV_REQ_FUA during write_zeroes · 465fe887
      由 Eric Blake 提交于 
      The block layer has a couple of cases where it can lose
Force Unit Access semantics when writing a large block of
zeroes, such that the request returns before the zeroes
have been guaranteed to land on underlying media.

SCSI does not support FUA during WRITESAME(10/16); FUA is only
supported if it falls back to WRITE(10/16).  But where the
underlying device is new enough to not need a fallback, it
means that any upper layer request with FUA semantics was
silently ignoring BDRV_REQ_FUA.

Conversely, NBD has situations where it can support FUA but not
ZERO_WRITE; when that happens, the generic block layer fallback
to bdrv_driver_pwritev() (or the older bdrv_co_writev() in qemu
2.6) was losing the FUA flag.

The problem of losing flags unrelated to ZERO_WRITE has been
latent in bdrv_co_do_write_zeroes() since commit aa7bfbff, but
back then, it did not matter because there was no FUA flag.  It
became observable when commit 93f5e6d8 paved the way for flags
that can impact correctness, when we should have been using
bdrv_co_writev_flags() with modified flags.  Compare to commit
9eeb6dd1, which got flag manipulation right in
bdrv_co_do_zero_pwritev().

Symptoms: I tested with qemu-io with default writethrough cache
(which is supposed to use FUA semantics on every write), and
targetted an NBD client connected to a server that intentionally
did not advertise NBD_FLAG_SEND_FUA.  When doing 'write 0 512',
the NBD client sent two operations (NBD_CMD_WRITE then
NBD_CMD_FLUSH) to get the fallback FUA semantics; but when doing
'write -z 0 512', the NBD client sent only NBD_CMD_WRITE.

The fix is do to a cleanup bdrv_co_flush() at the end of the
operation if any step in the middle relied on a BDS that does
not natively support FUA for that step (note that we don't
need to flush after every operation, if the operation is broken
into chunks based on bounce-buffer sizing).  Each BDS gains a
new flag .supported_zero_flags, which parallels the use of
.supported_write_flags but only when accessing a zero write
operation (the flags MUST be different, because of SCSI having
different semantics based on WRITE vs. WRITESAME; and also
because BDRV_REQ_MAY_UNMAP only makes sense on zero writes).

Also fix some documentation to describe -ENOTSUP semantics,
particularly since iscsi depends on those semantics.

Down the road, we may want to add a driver where its
.bdrv_co_pwritev() honors all three of BDRV_REQ_FUA,
BDRV_REQ_ZERO_WRITE, and BDRV_REQ_MAY_UNMAP, and advertise
this via bs->supported_write_flags for blocks opened by that
driver; such a driver should NOT supply .bdrv_co_write_zeroes
nor .supported_zero_flags.  But none of the drivers touched
in this patch want to do that (the act of writing zeroes is
different enough from normal writes to deserve a second
callback).
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Acked-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
      465fe887
    • E
      block: Make supported_write_flags a per-bds property · 4df863f3
      由 Eric Blake 提交于 
      Pre-patch, .supported_write_flags lives at the driver level, which
means we are blindly declaring that all block devices using a
given driver will either equally support FUA, or that we need a
fallback at the block layer.  But there are drivers where FUA
support is a per-block decision: the NBD block driver is dependent
on the remote server advertising NBD_FLAG_SEND_FUA (and has
fallback code to duplicate the flush that the block layer would do
if NBD had not set .supported_write_flags); and the iscsi block
driver is dependent on the mode sense bits advertised by the
underlying device (and is currently silently ignoring FUA requests
if the underlying device does not support FUA).

The fix is to make supported flags as a per-BDS option, set during
.bdrv_open().  This patch moves the variable and fixes NBD and iscsi
to set it only conditionally; later patches will then further
simplify the NBD driver to quit duplicating work done at the block
layer, as well as tackle the fact that SCSI does not support FUA
semantics on WRITESAME(10/16) but only on WRITE(10/16).
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Acked-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
      4df863f3
    • K
      block: Introduce bdrv_driver_pwritev() · 78a07294
      由 Kevin Wolf 提交于 
      This is a function that simply calls into the block driver for doing a
write, providing the byte granularity interface we want to eventually
have everywhere, and using whatever interface that driver supports.

This one is a bit more interesting than the version for reads: It adds
support for .bdrv_co_writev_flags() everywhere, so that drivers
implementing this function can drop .bdrv_co_writev() now.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
      78a07294
  7. 30 3月, 2016 2 次提交
  9. 01 3月, 2016 1 次提交
  11. 03 2月, 2016 2 次提交
  13. 20 1月, 2016 1 次提交
  15. 16 1月, 2016 1 次提交
    • Z
      iscsi: send readcapacity10 when readcapacity16 failed · 1cb6d137
      由 Zhu Lingshan 提交于 
      When play with Dell MD3000 target, for sure it
is a TYPE_DISK, but readcapacity16 would fail.
Then we find that readcapacity10 succeeded. It
looks like the target just support readcapacity10
even through it is a TYPE_DISK or have some
TYPE_ROM characteristics.

This patch can give a chance to send
readcapacity16 when readcapacity10 failed.
This patch is not harmful to original pathes
Signed-off-by: NZhu Lingshan <lszhu@suse.com>
Message-Id: <1451359934-9236-1-git-send-email-lszhu@suse.com>
[Don't fall through on UNIT ATTENTION. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      1cb6d137
  17. 11 1月, 2016 1 次提交
  19. 12 11月, 2015 2 次提交
  21. 05 11月, 2015 1 次提交
    • F
      iscsi: Translate scsi sense into error code · e01dd3da
      由 Fam Zheng 提交于 
      Previously we return -EIO blindly when anything goes wrong. Add a helper
function to parse sense fields and try to make the return code more
meaningful.

This also fixes the default werror configuration (enospc) when we're
using qcow2 on an iscsi lun. The old -EIO not being treated as out of
space error failed to trigger vm stop.
Signed-off-by: NFam Zheng <famz@redhat.com>
Message-Id: <1446699609-11376-1-git-send-email-famz@redhat.com>
[libiscsi 1.9 compatibility - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      e01dd3da
  23. 24 10月, 2015 1 次提交
  25. 08 9月, 2015 1 次提交
  27. 02 7月, 2015 2 次提交
    • P
      block/iscsi: restore compatiblity with libiscsi 1.9.0 · 9049736e
      由 Peter Lieven 提交于 
      RHEL7 and others are stuck with libiscsi 1.9.0 since there
unfortunately was an ABI breakage after that release.
Signed-off-by: NPeter Lieven <pl@kamp.de>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Message-id: 1435313881-19366-1-git-send-email-pl@kamp.de
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
      9049736e
    • P
      block/iscsi: add support for request timeouts · 5dd7a535
      由 Peter Lieven 提交于 
      libiscsi starting with 1.15 will properly support timeout of iscsi
commands. The default will remain no timeout, but this can
be changed via cmdline parameters, e.g.:

qemu -iscsi timeout=30 -drive file=iscsi://...

If a timeout occurs a reconnect is scheduled and the timed out command
will be requeued for processing after a successful reconnect.

The required API call iscsi_set_timeout is present since libiscsi
1.10 which was released in October 2013. However, due to some bugs
in the libiscsi code the use is not recommended before version 1.15.

Please note that this patch bumps the libiscsi requirement to 1.10
to have all function and macros defined. The patch fixes also a
off-by-one error in the NOP timeout calculation which was fixed
while touching these code parts.
Signed-off-by: NPeter Lieven <pl@kamp.de>
Message-id: 1434455107-19328-1-git-send-email-pl@kamp.de
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
      5dd7a535
  29. 23 6月, 2015 3 次提交
  31. 03 6月, 2015 1 次提交
  33. 28 4月, 2015 9 次提交
  35. 09 4月, 2015 1 次提交
    • P
      block/iscsi: handle zero events from iscsi_which_events · 05b685fb
      由 Peter Lieven 提交于 
      newer libiscsi versions may return zero events from iscsi_which_events.

In this case iscsi_service will return immediately without any progress.
To avoid busy waiting for iscsi_which_events to change we deregister all
read and write handlers in this case and schedule a timer to periodically
check iscsi_which_events for changed events.

Next libiscsi version will introduce async reconnects and zero events
are returned while libiscsi is waiting for a reconnect retry.
Signed-off-by: NPeter Lieven <pl@kamp.de>
Message-id: 1428437295-29577-1-git-send-email-pl@kamp.de
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
      05b685fb
  37. 10 3月, 2015 1 次提交
  39. 28 2月, 2015 1 次提交
  41. 03 1月, 2015 1 次提交
  43. 03 11月, 2014 3 次提交