From: Jan Kara <jack@suse.cz>
To: Jan Blunck <jblunck@suse.de>
Cc: linux-fsdevel@vger.kernel.org,
"Christoph Hellwig" <hch@infradead.org>,
"Alan Cox" <alan@lxorguk.ukuu.org.uk>,
"Linux-Kernel Mailinglist" <linux-kernel@vger.kernel.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
jkacur@redhat.com, "Arnd Bergmann" <arnd@arndb.de>,
"Frédéric Weisbecker" <fweisbec@gmail.com>,
"Jamie Lokier" <jamie@shareable.org>,
"H. Peter Anvin" <hpa@zytor.com>,
"Petr Vandrovec" <vandrove@vc.cvut.cz>,
"Anders Larsen" <al@alarsen.net>, "Jan Kara" <jack@suse.cz>
Subject: Re: [PATCH 13/15] Do not fallback to default_llseek() when readdir() uses BKL
Date: Fri, 20 Nov 2009 22:27:32 +0100 [thread overview]
Message-ID: <20091120212732.GD15631@duck.suse.cz> (raw)
In-Reply-To: <1258735245-25826-14-git-send-email-jblunck@suse.de>
On Fri 20-11-09 17:40:43, Jan Blunck wrote:
> Do not use the fallback default_llseek() if the readdir operation of the
> filesystem still uses the big kernel lock. Since llseek() modifies
> file->f_pos of the directory directly it may need locking to not confuse
> readdir which usually uses file->f_pos directly as well. Since the special
> characteristics of the BKL (unlocked on schedule) are not necessary in this
> case, the inode mutex can be used for locking as provided by
> generic_file_llseek(). This is only possible since all filesystems, except
> reiserfs, either use a directory as a flat file or with disk address
> offsets. Reiserfs on the other hand uses a 32bit hash off the filename as
> the offset so generic_file_llseek() can get used as well since the hash is
> always smaller than sb->s_maxbytes (= (512 << 32) - blocksize).
>
> Signed-off-by: Jan Blunck <jblunck@suse.de>
> ---
> fs/udf/dir.c | 1 +
For the UDF part:
Acked-by: Jan Kara <jack@suse.cz>
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
next prev parent reply other threads:[~2009-11-20 21:27 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-20 16:40 [PATCH 00/15] Remove BKL from default_llseek() and other issues (v2) Jan Blunck
2009-11-20 16:40 ` [PATCH 01/15] Introduce noop_llseek() Jan Blunck
2009-11-20 17:05 ` Jamie Lokier
2009-11-20 17:11 ` Jan Blunck
2009-11-21 16:56 ` Arnd Bergmann
2009-11-20 16:40 ` [PATCH 02/15] osst: Use noop_llseek() instead of default_llseek() Jan Blunck
2009-11-20 17:09 ` Jamie Lokier
2009-11-20 17:25 ` Jan Blunck
2009-11-20 16:40 ` [PATCH 03/15] osst: Update ppos instead of using file->f_pos Jan Blunck
2009-11-20 17:13 ` Jamie Lokier
2009-11-20 17:16 ` Jamie Lokier
2009-11-20 16:40 ` [PATCH 04/15] s390: tape_char should update " Jan Blunck
2009-11-20 16:40 ` [PATCH 05/15] flash_read should update ppos instead of file->f_pos Jan Blunck
2009-11-20 16:40 ` [PATCH 06/15] eeprom_read()/eeprom_write() " Jan Blunck
2009-11-20 16:40 ` [PATCH 07/15] sched_feat_write: Update " Jan Blunck
2009-11-20 16:40 ` [PATCH 08/15] airo: Use " Jan Blunck
2009-11-20 16:40 ` [PATCH 09/15] frv: remove "struct file *" argument from sysctl ->proc_handler Jan Blunck
2009-11-20 16:40 ` [PATCH 10/15] mISDN: Remove unnecessary test on f_pos Jan Blunck
2009-11-20 16:40 ` [PATCH 11/15] zcrypt: Use nonseekable_open() Jan Blunck
2009-11-20 16:40 ` [PATCH 12/15] rtc-m41t80: " Jan Blunck
2009-11-20 16:40 ` [PATCH 13/15] Do not fallback to default_llseek() when readdir() uses BKL Jan Blunck
2009-11-20 21:27 ` Jan Kara [this message]
2009-11-21 18:03 ` Anders Larsen
2009-11-20 16:40 ` [PATCH 14/15] BKL: Remove BKL from default_llseek() Jan Blunck
2009-11-20 16:40 ` [PATCH 15/15] BKL: Update documentation on llseek( \b) Jan Blunck
2009-11-20 17:02 ` [PATCH 15/15] BKL: Update documentation on llseek(\b) Alan Cox
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