On Wed, Sep 9, 2009 at 6:35 PM, Theodore Tso<tytso@xxxxxxx> wrote:
> On Wed, Sep 09, 2009 at 05:07:28PM -0700, Curt Wohlgemuth wrote:
>>
>> First, ext4_journal_forget() is called from ext4_forget() only when
>> we're journalling; without a journal, ext4_journal_forget() is only
>> called for various non-extent paths. ext4_forget() could be changed,
>> of course...
>
> Ext4_forget() calls either ext4_journal_forget() or
> ext4_journal_revoke(). So we need to fix up both functions.
>
> - Ted
>
> commit 4afdf0958f6f7b878e6d85cb4e0c0c12a0bd74e2
> Author: Theodore Ts'o <tytso@xxxxxxx>
> Date: Wed Sep 9 21:32:41 2009 -0400
>
> ext4: Use bforget() in no journal mode for ext4_journal_{forget,revoke}()
>
> When ext4 is using a journal, a metadata block which is deallocated
> must be passed into the journal layer so it can be dropped from the
> current transaction and/or revoked. This is done by calling the
> functions ext4_journal_forget() and ext4_journal_revoke(), which call
> jbd2_journal_forget(), and jbd2_journal_revoke(), respectively.
>
> Since the jbd2_journal_forget() and jbd2_journal_revoke() call
> bforget(), if ext4 is not using a journal, ext4_journal_forget() and
> ext4_journal_revoke() must call bforget() to avoid a dirty metadata
> block overwriting a block after it has been reallocated and reused for
> another inode's data block.
>
> Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
>
> diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c
> index eb27fd0..ecb9ca4 100644
> --- a/fs/ext4/ext4_jbd2.c
> +++ b/fs/ext4/ext4_jbd2.c
> @@ -44,7 +44,7 @@ int __ext4_journal_forget(const char *where, handle_t *handle,
> handle, err);
> }
> else
> - brelse(bh);
> + bforget(bh);
> return err;
> }
>
> @@ -60,7 +60,7 @@ int __ext4_journal_revoke(const char *where, handle_t *handle,
> handle, err);
> }
> else
> - brelse(bh);
> + bforget(bh);
> return err;
> }
This looks quite reasonable to me. And of course, your patch fixes
the brelse() calls that I added back in July.
Of course, validating this patch on my end will be tough; I need at
least a week of no corruptions to convince myself that the problem is
fixed, to the same degree that my call to sync_dirty_buffer() works.
Thanks,
Curt
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