* With respect to XFS Bitmap flush to disk
@ 2017-02-27 2:11 Halsey Pian
2017-02-27 11:23 ` Stefan Ring
2017-02-27 15:33 ` Eric Sandeen
0 siblings, 2 replies; 3+ messages in thread
From: Halsey Pian @ 2017-02-27 2:11 UTC (permalink / raw)
To: linux-xfs; +Cc: halsey.pian
Dear All,
Recently, I try to read analyze the bitmap of XFS file system, it seems that I cannot read the latest bitmap from hard disk involving the XFS, and cannot read the accurate info even after a long time. For example, i cannot get the relevant bitmap info after I add/delete a big file to/from XFS file system.
I tried several solution, and find it out that I must execute xfs_freeze for the XFS partition in CentOS7, and it seems that xfs_freeze doesn’t work for XFS version included in Redhat6.5, I must umount/mount the xfs, then I can get the latest bitmap info related to the latest data located in disk.
What strategy does XFS use to cache/flush bitmap to hard disk? How can I get the accurate bitmap info especially for Redhat6 series Operating System? Could you please give help on it?
Thanks in advance! ☺
Halsey Pian
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: With respect to XFS Bitmap flush to disk
2017-02-27 2:11 With respect to XFS Bitmap flush to disk Halsey Pian
@ 2017-02-27 11:23 ` Stefan Ring
2017-02-27 15:33 ` Eric Sandeen
1 sibling, 0 replies; 3+ messages in thread
From: Stefan Ring @ 2017-02-27 11:23 UTC (permalink / raw)
To: linux-xfs
On Mon, Feb 27, 2017 at 3:11 AM, Halsey Pian <halsey.pian@gmail.com> wrote:
>
> I tried several solution, and find it out that I must execute xfs_freeze for the XFS partition in CentOS7, and it seems that xfs_freeze doesn’t work for XFS version included in Redhat6.5, I must umount/mount the xfs, then I can get the latest bitmap info related to the latest data located in disk.
Why do you think that xfs_freeze does not work on el6?
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: With respect to XFS Bitmap flush to disk
2017-02-27 2:11 With respect to XFS Bitmap flush to disk Halsey Pian
2017-02-27 11:23 ` Stefan Ring
@ 2017-02-27 15:33 ` Eric Sandeen
1 sibling, 0 replies; 3+ messages in thread
From: Eric Sandeen @ 2017-02-27 15:33 UTC (permalink / raw)
To: Halsey Pian, linux-xfs
On 2/26/17 8:11 PM, Halsey Pian wrote:
> Dear All,
>
> Recently, I try to read analyze the bitmap of XFS file system, it
> seems that I cannot read the latest bitmap from hard disk involving
> the XFS, and cannot read the accurate info even after a long time.
> For example, i cannot get the relevant bitmap info after I add/delete
> a big file to/from XFS file system.
In general, attempting to read metadata from a mounted block device
isn't going to be reliable. For one, changes may only be staged
in the log, and not yet in their final disk location.
> I tried several solution, and find it out that I must execute
> xfs_freeze for the XFS partition in CentOS7, and it seems that
> xfs_freeze doesn’t work for XFS version included in Redhat6.5, I must
> umount/mount the xfs, then I can get the latest bitmap info related
> to the latest data located in disk.
>
> What strategy does XFS use to cache/flush bitmap to hard disk? How
> can I get the accurate bitmap info especially for Redhat6 series
> Operating System? Could you please give help on it?
The short answer is "you can't." Directly reading the block device
while mounted isn't a supported use of the filesystem.
What are you trying to do, here?
Thanks,
-Eric
> Thanks in advance! ☺
>
>
>
>
> Halsey Pian
>
>
> -- To unsubscribe from this list: send the line "unsubscribe
> linux-xfs" in the body of a message to majordomo@vger.kernel.org More
> majordomo info at http://vger.kernel.org/majordomo-info.html
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2017-02-27 15:41 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-02-27 2:11 With respect to XFS Bitmap flush to disk Halsey Pian
2017-02-27 11:23 ` Stefan Ring
2017-02-27 15:33 ` Eric Sandeen
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.