Re: FileFallocate misbehaving on XFS

On 2024-Dec-11, Andres Freund wrote:

> One thing that I think we should definitely do is to include more detail in
> the error message. mdzeroextend()'s error messages don't include how many
> blocks the relation was to be extended by. Neither mdextend() nor
> mdzeroextend() include the offset at which the extension failed.

I proposed a patch at
https://postgr.es/m/202409110955.6njbwzm4ocus@alvherre.pgsql

FileFallocate failure:
        errmsg("could not allocate additional %lld bytes from position %lld in file \"%s\": %m",
               (long long) addbytes, (long long) seekpos,
               FilePathName(v->mdfd_vfd)),

FileZero failure:
        errmsg("could not zero additional %lld bytes from position %lld file \"%s\": %m",
               (long long) addbytes, (long long) seekpos,
               FilePathName(v->mdfd_vfd)),

I'm not sure that we need to talk about blocks, given that the
underlying syscalls don't work in blocks anyway.  IMO we should just
report bytes.

-- 
Álvaro Herrera               48°01'N 7°57'E  —  https://www.EnterpriseDB.com/
"No hay ausente sin culpa ni presente sin disculpa" (Prov. francés)