linux-kernel - Re: [patch 12/12] fuse: add blksize field to fuse

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 05 Oct 2007 01:15:05 +0200
From:	Miklos Szeredi <miklos@...redi.hu>
To:	akpm@...ux-foundation.org
CC:	miklos@...redi.hu, linux-kernel@...r.kernel.org
Subject: Re: [patch 12/12] fuse: add blksize field to fuse_attr

> > From: Miklos Szeredi <mszeredi@...e.cz>
> > 
> > Allow the userspace filesystem to supply a blksize value to be
> > returned by stat() and friends.  If the field is zero, it defaults to
> > the old PAGE_CACHE_SIZE value.
> > 
> 
> Why does fuse need this feature?

There are cases, when the filesystem will be passed the buffer from a
single read or write call, namely:

 1) in 'direct-io' mode (not O_DIRECT), read/write requests don't go
    through the page cache, but go directly to the userspace fs

 2) currently buffered writes are done with single page requests, but
    if Nick's ->perform_write() patch goes it, it will be possible to
    do larger write requests.  But only if the original write() was
    also bigger than a page.


In these cases the filesystem might want to give a hint to the app
about the optimal I/O size.

Miklos
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/