* misreported st_blocks (AllocationSize)
@ 2022-05-11 19:33 Steve French
2022-05-11 20:20 ` Darrick J. Wong
0 siblings, 1 reply; 2+ messages in thread
From: Steve French @ 2022-05-11 19:33 UTC (permalink / raw)
To: linux-fsdevel; +Cc: samba-technical, CIFS
Was investigating trying to fix emulation of some fallocate flags, and
was wondering how common is it for a fs to very loosely report
allocation size (st_blocks) for a file - ie the allocation sizes does
not match the allocate ranges returned by fiemap (or
SEEK_HOLE/SEEK_DATA). Presumably there are Linux fs that coalesce
ranges on the fly so allocation sizes may be a 'guess' for some fs.
How common is this for it to be off?
--
Thanks,
Steve
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: misreported st_blocks (AllocationSize)
2022-05-11 19:33 misreported st_blocks (AllocationSize) Steve French
@ 2022-05-11 20:20 ` Darrick J. Wong
0 siblings, 0 replies; 2+ messages in thread
From: Darrick J. Wong @ 2022-05-11 20:20 UTC (permalink / raw)
To: Steve French; +Cc: linux-fsdevel, samba-technical, CIFS
On Wed, May 11, 2022 at 02:33:01PM -0500, Steve French wrote:
> Was investigating trying to fix emulation of some fallocate flags, and
> was wondering how common is it for a fs to very loosely report
> allocation size (st_blocks) for a file - ie the allocation sizes does
> not match the allocate ranges returned by fiemap (or
> SEEK_HOLE/SEEK_DATA). Presumably there are Linux fs that coalesce
> ranges on the fly so allocation sizes may be a 'guess' for some fs.
>
> How common is this for it to be off?
Very common -- XFS reports /all/ file block usage in st_blocks,
including the extent mapping trees and staging areas for copy on write.
--D
> --
> Thanks,
>
> Steve
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-05-11 19:33 misreported st_blocks (AllocationSize) Steve French
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