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Re: [PATCH] xfs_io: v7 add the lseek() SEEK_DATA/SEEK_HOLE support

To: Eric Sandeen <sandeen@xxxxxxxxxxx>
Subject: Re: [PATCH] xfs_io: v7 add the lseek() SEEK_DATA/SEEK_HOLE support
From: Mark Tinguely <tinguely@xxxxxxx>
Date: Fri, 23 Aug 2013 10:18:49 -0500
Cc: xfs-oss <xfs@xxxxxxxxxxx>
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <52177AA0.5080403@xxxxxxxxxxx>
References: <20130822213148.224998379@xxxxxxx> <52169488.2040303@xxxxxxxxxxx> <521762F4.4050603@xxxxxxx> <08C24AC4-BA56-41C5-BC5C-0DBE2A5C1033@xxxxxxxxxxx> <5217785B.9010804@xxxxxxx> <52177AA0.5080403@xxxxxxxxxxx>
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On 08/23/13 10:07, Eric Sandeen wrote:
On 8/23/13 9:57 AM, Mark Tinguely wrote:
On 08/23/13 08:34, Eric Sandeen wrote:
On Aug 23, 2013, at 8:26 AM, Mark Tinguely<tinguely@xxxxxxx>   wrote:

On 08/22/13 17:45, Eric Sandeen wrote:
On 8/22/13 4:31 PM, Mark Tinguely wrote:

Add the lseek SEEK_DATA/SEEK_HOLE support into xfs_io.
The result from the lseek() call will be printed to the output.
For example:

xfs_io>    seek -h 609k
HOLE    630784

Signed-off-by: Mark Tinguely<tinguely@xxxxxxx>
   version 7 or 8 - Eric what number is this?

Go for 13, for luck!

I think this looks ok, I won't torture you any longer.  If there's anything
to fix up when it really gets used in earnest we can do it then.

(it crossed my mind that for the "-r" and "-a" invocations it might be good to 
out the offset which was sent for each SEEK_* "whence," but *shrug*)

Thanks for all the iterations,

Reviewed-by: Eric Sandeen<sandeen@xxxxxxxxxx>

Rich, hold off on commit, I can quickly add the whence. We can see how she 

Was just an idle thought... See if it makes sense I guess...


without whence:
xfs_io>  seek -ar 0
HOLE    0
DATA    528384
HOLE    532480
DATA    819200
HOLE    823296

xfs_io>  seek -dh 512k
HOLE    524288
DATA    528384

xfs_io>  seek -rd 0
DATA    528384
DATA    819200


after with whence:

Don't hate me, but if you do this, now I think it needs a header ;)

I was looking at the output and knew you were going to suggest it.

I dunno, what do you think, does it have value in general?

for -ar no because we are alternating data and hole - the last result is the new input. But for all the holes and all the data it is an improvement.

The question is should we print the starting offset in only the "-r" option or for all cases to be consistent?

I vote to just add the starting offset in all output...

I'd propose this:  Merge it as I reviewed it, if you're happy,
just printing the results of the seeks.

Make sense to have it. Let me post the new version. of course the real luck of the irish is with me today, v7 has a bug in it. "wow, I could have had a v8".

I was thinking that down the line just for edge case testing
we might want to be able to pass in other "whences."

Later enhancements could also add a "-w" option to explicitly print
out the passed-in or recursively-selected "whence" if that output
is desired for comparisons or sanity checking.

Might be good to stop polishing this for now and do any other
enhancements in later patches.

Your call,


xfs_io>  seek -ar 0:
HOLE    0       0
DATA    0       528384
HOLE    528384  532480
DATA    532480  819200
HOLE    819200  823296

xfs_io>  seek -dh 512k:

HOLE    524288
DATA    528384

xfs_io>  seek -rd 0
DATA    0       528384
DATA    532480  819200

Seems to make most sense in the case of -rd and -rh



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