Date: Wed, 05 Jun 2024 09:48:55 +0100 From: Norman Gray <gray@nxg.name> To: =?utf-8?q?Dag-Erling_Sm=C3=B8rgrav?= <des@FreeBSD.org> Cc: FreeBSD Questions <freebsd-questions@freebsd.org> Subject: Re: quotactl(2) units of reported sizes on ZFS Message-ID: <28D77DB4-B8F1-4680-8891-F3CA454FC9F4@nxg.name> In-Reply-To: <861q5c4akw.fsf@ltc.des.dev> References: <432AE47C-1502-4BFA-B680-7DAF6DDC601A@nxg.name> <861q5c4akw.fsf@ltc.des.dev>
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Dag-Erling, hello. On 4 Jun 2024, at 23:17, Dag-Erling Sm=C3=B8rgrav wrote: > Norman Gray <gray@nxg.name> writes: >> The call quotactl(2) reports quota sizes in units of 'blocks', but how= >> big is a block? Traditionally, of course, the answer is 512B, [...] > > You could simply have stopped there, it's a POSIX requirement. That's an interesting direction to come from -- thanks! Can you point to chapter and verse, though? Looking at [1], and specific= ally the specification of the contents of sys/stat.h [2], I find: > The unit for the st_blocks member of the stat structure is not defined = within POSIX.1-2017. In some implementations it is 512 bytes. It may diff= er on a file system basis. There is no correlation between values of the = st_blocks and st_blksize, and the f_bsize (from <sys/statvfs.h>) structur= e members. That's stat.h, of course, rather than anything to do with quotas specific= ally. But POSIX doesn't mention quotas (not surprisingly), so if the quo= tactl manpage were going to silently adopt a POSIX unit definition, it's = stat.h I'd expect it to come from. Individual utilities -- for example `ulimit` [3] or `df` -- document that= one or other argument is in units of 512B 'blocks', but that's a user-in= terface issue. Best wishes, Norman [1] The Open Group Base Specifications Issue 7, 2018 edition <https://pub= s.opengroup.org/onlinepubs/9699919799/toc.htm> [2] https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/sys_stat.h.= html [3] https://pubs.opengroup.org/onlinepubs/9699919799/utilities/ulimit.htm= l -- = Norman Gray : https://nxg.me.uk
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