Messages in this thread | | | Date | Wed, 3 Apr 2024 16:29:14 +0800 | Subject | Re: [PATCH v3 00/13] fiemap extension for more physical information | From | Gao Xiang <> |
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Hi,
On 2024/4/3 15:22, Sweet Tea Dorminy wrote: > For many years, various btrfs users have written programs to discover > the actual disk space used by files, using root-only interfaces. > However, this information is a great fit for fiemap: it is inherently > tied to extent information, all filesystems can use it, and the > capabilities required for FIEMAP make sense for this additional > information also. > > Hence, this patchset adds various additional information to fiemap, > and extends filesystems (but not iomap) to return it. This uses some of > the reserved padding in the fiemap extent structure, so programs unaware > of the changes will be unaffected.
I'm not sure why here iomap was excluded technically or I'm missing some previous comments?
> > This is based on next-20240403. I've tested the btrfs part of this with > the standard btrfs testing matrix locally and manually, and done minimal > testing of the non-btrfs parts. > > I'm unsure whether btrfs should be returning the entire physical extent > referenced by a particular logical range, or just the part of the > physical extent referenced by that range. The v2 thread has a discussion > of this.
Could you also make iomap support new FIEMAP physical extent information? since compressed EROFS uses iomap FIEMAP interface to report compressed extents ("z_erofs_iomap_report_ops") but there is no way to return correct compressed lengths, that is unexpected.
Thanks, Gao Xiang
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