On Fri, Jul 07, 2017 at 06:25:24PM -0400, John Snow wrote: > Last time, on DRAGON BALL Q:
Didn't know of this before; just learnt the reference. > On 07/06/2017 10:36 AM, Kashyap Chamarthy wrote: > > [A lot of good documentation] > > > + > > +So, the following is the flow for `block-commit_Case-3`_ -- to convert a > > +disk image chain such as this:: > > + > > Maybe drop the "So, " > > "The following is the flow for 'Block Commit Case 3' to convert a disk > image chain such as this:" Fixed in v6. > > + [A] <-- [B] <-- [C] <-- [D] > > + > > +Into (where content from all the subsequent overlays, [B], and [C], > > +including the active layer, [D], is committed back to [A] -- which is > > +where live QEMU is performing all its current writes):: > > + > > "Into: " > > > + [A] > > + > > "Where content from all [...] its current writes." Fixed in v6. [...] > > +Then, (optionally) query for the status of the active block operations > > +(we can see the 'commit' job is now ready to be completed, as indicated > > +by the line *"ready": true*):: > > + > > Then, optionally query for the status of the active block operations. We > can see the 'commit' job is now ready to be completed, as indicated by > the line *"ready": true*. Fixed in v6. [...] > > +.. note:: > > + The invocation for rest of the cases (2, 4, and 5), discussed in the > > + previous section, is omitted for brevity. > > + > > As a joke I almost want to write "The invocation for cases 2, 4, and 5 > are left as an exercise to the reader." Heh, I considered that, too. Maybe I should do it. But somehow I can't bring myself to. :-) > > +(1) Issuing the command ``block-job-cancel``, after it emits the event > > nix the comma Nixed in v6. [...] > > +(2) Issuing the command ``block-job-complete``, after it emits the event > > nix the comma In v6. [...] > > +A note on synchronization modes -- determines *what* part of the disk > > +image chain must be copied to the target. Currently, there are four > > +different kinds: > > + > > You've got a note here, followed by a note box. Maybe just: > > "About synchronization modes: The synchronization mode determines > *which* part of the disk image chain will be copied to the target. > Currently, there are four different kinds:" Yep, fixed as such in v6. (And I also see that two occurences of "synchronization mode" is OK in this instance.) [...] > > + .. note:: In the case of ``drive-backup`` (or ``blockdev-backup``), > > + the behavior of ``none`` sychronization mode is different. > > + Normally, a ``backup`` job consists of two parts: Anything > > + that is overwritten by the guest is first copied out to > > + the backup, and in the background the whole image is > > + copied from start to end. With ``sync=none``, it's only > > + the first part. [...] > > +(5) Gracefully complete the 'mirror' block device job, and observe for > > + the event ``BLOCK_JOB_COMPLETED`` > > + > > "observe for the event" is slightly awkward Replaced it with "notice the event" (fixed 5 occurences throughout the doc). > > +(6) Shutdown the guest, by issuing the QMP ``quit`` command, so that > > + caches are flushed > > + > > nix both commas Nixed in v6. [...] > > +QMP invocation for ``blockdev-backup`` > > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > + > > +Given, a disk image chain of depth 1, where image [B] is the active > > +overlay (live QEMU is writing to it):: > > + > > Given a disk image chain of depth 1 where image [B] is the active > overlay (live QEMU is writing it) Fixed in v6. > > + [A] <-- [B] > > + > > +The following is the procedure to copy the content from the entire chain > > +to a target image (say, [E]), which has the full content from [A] and > > +[B]. > > + > > +Create the overlay, [B]:: > > the overlay [B] Likewise :-) > > +Create a target image, that will contain the copy:: > > sans comma Yep. > > + > > + $ qemu-img create -f qcow2 e.qcow2 39M > > + > > +Then, add it to QEMU via ``blockdev-add``:: > > + > > and one more time Sure. </embarassed> > > + > > +Then, invoke ``blockdev-backup``, to copy the contents from the entire > > +image chain, consisting of images [A], and [B], to the target image > > +'e.qcow2':: > > + > > Then invoke bd-b to copy the contents from the entire image chain, > consisting of images [A] and [B] to the target image e.qcow2: Comma-wildness again. Fixed in v6. > > +Once the above 'backup' operation has completed, an event, > > +``BLOCK_JOB_COMPLETED``, will be emitted, signalling successful > > +completion. > > + > > "the event BLOCK_JOB_COMPLETED will be emitted, signalling" Fixed in v6. [...] > > +The end result will be, the image 'e.qcow2' containing a > > Goodbye sweet comma, savor the void :-) Yep, v6 savors a lot of void. > > +point-in-time backup of the disk image chain -- i.e. contents from > > +images [A], and [B] at the time the ``blockdev-backup`` command was > > +initiated. > > + > > images [A] and [B] Yep. > > +One way to confirm the backup disk image contains the identical content > > +with the disk image chain is to compare the backup, and the contents of > > Could kill this comma too. Killed in v6. [...] > That's all I got for now. It's looking very good, thank you for your > time. Please consider all of my suggestions are just that. There is a > reason I am not an English professor :) They are useful suggestions. :-) I'm a stickler for English, and I like to get it right. Appreciate the patience! -- /kashyap
