Re: [PATCH v3 02/18] jbd2: change jbd2_journal_invalidatepage to accept length

[Jan Kara <jack@suse.cz>]

On Tue 09-04-13 11:14:11, Lukas Czerner wrote:
> invalidatepage now accepts range to invalidate and there are two file
> system using jbd2 also implementing punch hole feature which can benefit
> from this. We need to implement the same thing for jbd2 layer in order to
> allow those file system take benefit of this functionality.
> 
> This commit adds length argument to the jbd2_journal_invalidatepage()
> and updates all instances in ext4 and ocfs2.
  Looks good. You can add:
Reviewed-by: Jan Kara <jack@suse.cz>

								Honza
> 
> Signed-off-by: Lukas Czerner <lczerner@redhat.com>
> ---
>  fs/ext4/inode.c       |    3 ++-
>  fs/jbd2/transaction.c |   24 +++++++++++++++++-------
>  fs/ocfs2/aops.c       |    3 ++-
>  include/linux/jbd2.h  |    2 +-
>  4 files changed, 22 insertions(+), 10 deletions(-)
> 
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index f5bf189..69595f5 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -3000,7 +3000,8 @@ static int __ext4_journalled_invalidatepage(struct page *page,
>  	if (offset == 0)
>  		ClearPageChecked(page);
>  
> -	return jbd2_journal_invalidatepage(journal, page, offset);
> +	return jbd2_journal_invalidatepage(journal, page, offset,
> +					   PAGE_CACHE_SIZE - offset);
>  }
>  
>  /* Wrapper for aops... */
> diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
> index 325bc01..d334e17 100644
> --- a/fs/jbd2/transaction.c
> +++ b/fs/jbd2/transaction.c
> @@ -2027,18 +2027,23 @@ zap_buffer_unlocked:
>   * void jbd2_journal_invalidatepage()
>   * @journal: journal to use for flush...
>   * @page:    page to flush
> - * @offset:  length of page to invalidate.
> + * @offset:  start of the range to invalidate
> + * @length:  length of the range to invalidate
>   *
> - * Reap page buffers containing data after offset in page. Can return -EBUSY
> - * if buffers are part of the committing transaction and the page is straddling
> - * i_size. Caller then has to wait for current commit and try again.
> + * Reap page buffers containing data after in the specified range in page.
> + * Can return -EBUSY if buffers are part of the committing transaction and
> + * the page is straddling i_size. Caller then has to wait for current commit
> + * and try again.
>   */
>  int jbd2_journal_invalidatepage(journal_t *journal,
>  				struct page *page,
> -				unsigned long offset)
> +				unsigned int offset,
> +				unsigned int length)
>  {
>  	struct buffer_head *head, *bh, *next;
> +	unsigned int stop = offset + length;
>  	unsigned int curr_off = 0;
> +	int partial_page = (offset || length < PAGE_CACHE_SIZE);
>  	int may_free = 1;
>  	int ret = 0;
>  
> @@ -2047,6 +2052,8 @@ int jbd2_journal_invalidatepage(journal_t *journal,
>  	if (!page_has_buffers(page))
>  		return 0;
>  
> +	BUG_ON(stop > PAGE_CACHE_SIZE || stop < length);
> +
>  	/* We will potentially be playing with lists other than just the
>  	 * data lists (especially for journaled data mode), so be
>  	 * cautious in our locking. */
> @@ -2056,10 +2063,13 @@ int jbd2_journal_invalidatepage(journal_t *journal,
>  		unsigned int next_off = curr_off + bh->b_size;
>  		next = bh->b_this_page;
>  
> +		if (next_off > stop)
> +			return 0;
> +
>  		if (offset <= curr_off) {
>  			/* This block is wholly outside the truncation point */
>  			lock_buffer(bh);
> -			ret = journal_unmap_buffer(journal, bh, offset > 0);
> +			ret = journal_unmap_buffer(journal, bh, partial_page);
>  			unlock_buffer(bh);
>  			if (ret < 0)
>  				return ret;
> @@ -2070,7 +2080,7 @@ int jbd2_journal_invalidatepage(journal_t *journal,
>  
>  	} while (bh != head);
>  
> -	if (!offset) {
> +	if (!partial_page) {
>  		if (may_free && try_to_free_buffers(page))
>  			J_ASSERT(!page_has_buffers(page));
>  	}
> diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
> index ecb86ca..7c47755 100644
> --- a/fs/ocfs2/aops.c
> +++ b/fs/ocfs2/aops.c
> @@ -608,7 +608,8 @@ static void ocfs2_invalidatepage(struct page *page, unsigned int offset,
>  {
>  	journal_t *journal = OCFS2_SB(page->mapping->host->i_sb)->journal->j_journal;
>  
> -	jbd2_journal_invalidatepage(journal, page, offset);
> +	jbd2_journal_invalidatepage(journal, page, offset,
> +				    PAGE_CACHE_SIZE - offset);
>  }
>  
>  static int ocfs2_releasepage(struct page *page, gfp_t wait)
> diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
> index f9fe889..8c34abd 100644
> --- a/include/linux/jbd2.h
> +++ b/include/linux/jbd2.h
> @@ -1090,7 +1090,7 @@ extern int	 jbd2_journal_dirty_metadata (handle_t *, struct buffer_head *);
>  extern int	 jbd2_journal_forget (handle_t *, struct buffer_head *);
>  extern void	 journal_sync_buffer (struct buffer_head *);
>  extern int	 jbd2_journal_invalidatepage(journal_t *,
> -				struct page *, unsigned long);
> +				struct page *, unsigned int, unsigned int);
>  extern int	 jbd2_journal_try_to_free_buffers(journal_t *, struct page *, gfp_t);
>  extern int	 jbd2_journal_stop(handle_t *);
>  extern int	 jbd2_journal_flush (journal_t *);
> -- 
> 1.7.7.6
> 
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-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

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