Messages in this thread |  | | Date | Mon, 24 Feb 2003 11:20:09 +0100 | From | Andries Brouwer <> | Subject | Re: [PATCH] comments on st_blksize and f_bsize for 2.5 |
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On Tue, Feb 18, 2003 at 08:25:40PM +0300, Hans Reiser wrote:
> Since a few applications, and the linux manpages, seem to not really > understand what these are for, they need comments like SUSv2 has for > them. A larger discussion will be provided if requested.
> + unsigned int st_blksize; /* Optimal I/O size */
> + int f_bsize; /* Filesystem blocksize */
Yes, discussion - I wouldnt mind seeing details.
The trivial part is st_blksize: all agree. Quoting the man page:
The value st_blksize gives the "preferred" blocksize for efficient file system I/O. (Writing to a file in smaller chunks may cause an inefficient read-modify-rewrite.)
The nontrivial part is f_bsize. As far as I can see BSD and SYSV and SUS all differ. And there are the use in struct statfs and the use in struct statvfs that are nonequivalent.
Maybe BSD f_iosize, f_bsize in statfs corresponds to SYSV f_bsize, f_frsize in statfs. Linux is again a bit different.
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