From: Christoph Hellwig <hch@infradead.org>
To: Alessio Igor Bogani <abogani@texware.it>
Cc: Jan Kara <jack@suse.cz>, Arnd Bergmann <arnd@arndb.de>,
Christoph Hellwig <hch@infradead.org>,
Tim Bird <tim.bird@am.sony.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 4/4] udf: Replace bkl with a mutex for protect udf_sb_info struct
Date: Sat, 6 Nov 2010 14:16:17 -0400 [thread overview]
Message-ID: <20101106181617.GE13315@infradead.org> (raw)
In-Reply-To: <1289065631-2256-4-git-send-email-abogani@texware.it>
> + mutex_lock(&sbi->lock);
> result = udf_relocate_blocks(inode->i_sb,
> old_block, &new_block);
> + mutex_unlock(&sbi->lock);
Moving the locking inside udf_relocate_blocks would be cleaner.
> @@ -570,7 +569,7 @@ static int udf_remount_fs(struct super_block *sb, int *flags, char *options)
> if (!udf_parse_options(options, &uopt, true))
> return -EINVAL;
>
> - lock_kernel();
> + mutex_lock(&sbi->lock);
What are you protecting against here? Concurrent remount calls are
protects against by the VFS. Is there any reader that takes sbi->lock
to get a consistent view of the various options? It doesn't seem you
introduce one in this series, so it seems we could do fine without any
locking.
> - unlock_kernel();
> return -ENOMEM;
> }
>
> + mutex_init(&sbi->lock);
> + mutex_lock(&sbi->lock);
What are you locking against here? I can't fine anything that puts the
superblock on a global list in fill_super, and I can't find any code
that would look a superblock up that's not fully set up. I don't think
synchronization here in fill_super is needed at all.
> + /* Serialize writer access, replace the old bkl */
> + struct mutex lock;
Same comment as for the per-inode mutex applies here, too.
next prev parent reply other threads:[~2010-11-06 18:16 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-06 17:47 [PATCH 1/4] udf: Add missed protection for s_lvid_dirty Alessio Igor Bogani
2010-11-06 17:47 ` [PATCH 2/4] udf: Remove unnecessary bkl usages Alessio Igor Bogani
2010-11-06 18:06 ` Christoph Hellwig
2010-11-06 17:47 ` [PATCH 3/4] udf: Replace bkl with a mutex for protect udf_inode_info struct Alessio Igor Bogani
2010-11-06 18:10 ` Christoph Hellwig
2010-11-06 17:47 ` [PATCH 4/4] udf: Replace bkl with a mutex for protect udf_sb_info struct Alessio Igor Bogani
2010-11-06 18:16 ` Christoph Hellwig [this message]
2010-11-06 18:05 ` [PATCH 1/4] udf: Add missed protection for s_lvid_dirty Christoph Hellwig
2010-11-07 14:14 ` Jan Kara
2010-11-07 14:27 ` Christoph Hellwig
2010-11-07 15:06 ` Jan Kara
2010-11-15 22:46 ` Arnd Bergmann
2010-11-16 0:43 ` Jan Kara
2010-11-16 13:03 ` Alessio Igor Bogani
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