From: Theodore Ts'o <tytso@mit.edu>
To: "Lukáš Czerner" <lczerner@redhat.com>
Cc: Ext4 Developers List <linux-ext4@vger.kernel.org>
Subject: Re: [PATCH 4/7] ext4: refactor punch hole code
Date: Tue, 26 Mar 2013 22:38:16 -0400 [thread overview]
Message-ID: <20130327023816.GC2697@thunk.org> (raw)
In-Reply-To: <alpine.LFD.2.00.1303261334060.2455@(none)>
On Tue, Mar 26, 2013 at 01:54:19PM +0100, Lukáš Czerner wrote:
> > + /* Wait all existing dio workers, newcomers will block on i_mutex */
> > + ext4_inode_block_unlocked_dio(inode);
>
> This was not present in the indirect punch hole code, does it means
> that there was a bug ? If so maybe it's worth mentioning in the
> description?
Yes, I'm pretty sure it was a bug. The
ext4_inode_block_unlocked_dio() call was added in the extents code
path by commit 02d262dffcf4c. The problem is that i_mutex will not
block DIO readers in dioread_nolock mode. One of the problems with
not having done the code refactorization earlier was that a bug fixed
in one code path doesn't necessarily get fixed in another.
I'll add a comment to this effect in the commit description.
> > + if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
> > + credits = ext4_writepage_trans_blocks(inode);
> > + else
> > + credits = ext4_blocks_for_truncate(inode);
> > + handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
> > + ext4_blocks_for_truncate(inode));
>
> Hmm, shouldn't we be using 'credits' instead of
> ext4_blocks_for_truncate(inode) here ?
Yes, good catch!
Thanks,
- Ted
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next prev parent reply other threads:[~2013-03-27 2:38 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-25 0:06 [PATCH 0/7] ext4 code simplification and clean ups Theodore Ts'o
2013-03-25 0:06 ` [PATCH 1/7] ext4: collapse handling of data=ordered and data=writeback codepaths Theodore Ts'o
2013-03-27 12:57 ` Lukáš Czerner
2013-03-25 0:06 ` [PATCH 2/7] ext4: fold ext4_generic_write_end() into ext4_write_end() Theodore Ts'o
2013-03-27 12:58 ` Lukáš Czerner
2013-03-27 15:35 ` Jan Kara
2013-03-25 0:06 ` [PATCH 3/7] ext4: fold ext4_alloc_blocks() in ext4_alloc_branch() Theodore Ts'o
2013-03-27 17:01 ` Jan Kara
2013-03-25 0:06 ` [PATCH 4/7] ext4: refactor punch hole code Theodore Ts'o
[not found] ` <alpine.LFD.2.00.1303261334060.2455@(none)>
2013-03-27 2:38 ` Theodore Ts'o [this message]
2013-03-27 10:49 ` Lukáš Czerner
2013-03-25 0:06 ` [PATCH 5/7] ext4: refactor truncate code Theodore Ts'o
[not found] ` <alpine.LFD.2.00.1303271128480.2455@(none)>
2013-03-27 12:36 ` Theodore Ts'o
2013-03-27 13:31 ` Lukáš Czerner
2013-03-25 0:06 ` [PATCH 6/7] ext4: add mutex_is_locked() assertion to ext4_truncate() Theodore Ts'o
2013-03-26 9:31 ` Lukáš Czerner
2013-03-27 2:29 ` Theodore Ts'o
2013-03-25 0:06 ` [PATCH 7/7] ext4: add might_sleep() annotations Theodore Ts'o
2013-03-26 9:48 ` Lukáš Czerner
2013-03-26 9:49 ` Lukáš Czerner
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