Re: [PATCH v3 04/18] jbd: change journal_invalidatepage() to accept length

[Jan Kara <jack@suse.cz>]

On Tue 09-04-13 11:14:13, Lukas Czerner wrote:
> ->invalidatepage() aop now accepts range to invalidate so we can make
> use of it in journal_invalidatepage() and all the users in ext3 file
> system. Also update ext3 trace point to print out length argument.
> 
> Signed-off-by: Lukas Czerner <lczerner@redhat.com>
  Looks good. You can add:
Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/ext3/inode.c             |    6 +++---
>  fs/jbd/transaction.c        |   19 ++++++++++++++-----
>  include/linux/jbd.h         |    2 +-
>  include/trace/events/ext3.h |   12 +++++++-----
>  4 files changed, 25 insertions(+), 14 deletions(-)
> 
> diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
> index 349d4ce..b12936b 100644
> --- a/fs/ext3/inode.c
> +++ b/fs/ext3/inode.c
> @@ -1828,15 +1828,15 @@ static void ext3_invalidatepage(struct page *page, unsigned int offset,
>  {
>  	journal_t *journal = EXT3_JOURNAL(page->mapping->host);
>  
> -	trace_ext3_invalidatepage(page, offset);
> +	trace_ext3_invalidatepage(page, offset, length);
>  
>  	/*
>  	 * If it's a full truncate we just forget about the pending dirtying
>  	 */
> -	if (offset == 0)
> +	if (offset == 0 && length == PAGE_CACHE_SIZE)
>  		ClearPageChecked(page);
>  
> -	journal_invalidatepage(journal, page, offset);
> +	journal_invalidatepage(journal, page, offset, length);
>  }
>  
>  static int ext3_releasepage(struct page *page, gfp_t wait)
> diff --git a/fs/jbd/transaction.c b/fs/jbd/transaction.c
> index 071d690..a1fef89 100644
> --- a/fs/jbd/transaction.c
> +++ b/fs/jbd/transaction.c
> @@ -2020,16 +2020,20 @@ zap_buffer_unlocked:
>   * void journal_invalidatepage() - invalidate a journal page
>   * @journal: journal to use for flush
>   * @page:    page to flush
> - * @offset:  length of page to invalidate.
> + * @offset:  offset of the range to invalidate
> + * @length:  length of the range to invalidate
>   *
> - * Reap page buffers containing data after offset in page.
> + * Reap page buffers containing data in specified range in page.
>   */
>  void 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;
>  
>  	if (!PageLocked(page))
> @@ -2037,6 +2041,8 @@ void journal_invalidatepage(journal_t *journal,
>  	if (!page_has_buffers(page))
>  		return;
>  
> +	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. */
> @@ -2046,11 +2052,14 @@ void journal_invalidatepage(journal_t *journal,
>  		unsigned int next_off = curr_off + bh->b_size;
>  		next = bh->b_this_page;
>  
> +		if (next_off > stop)
> +			return;
> +
>  		if (offset <= curr_off) {
>  			/* This block is wholly outside the truncation point */
>  			lock_buffer(bh);
>  			may_free &= journal_unmap_buffer(journal, bh,
> -							 offset > 0);
> +							 partial_page);
>  			unlock_buffer(bh);
>  		}
>  		curr_off = next_off;
> @@ -2058,7 +2067,7 @@ void 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/include/linux/jbd.h b/include/linux/jbd.h
> index c8f3297..d02e16c 100644
> --- a/include/linux/jbd.h
> +++ b/include/linux/jbd.h
> @@ -840,7 +840,7 @@ extern void	 journal_release_buffer (handle_t *, struct buffer_head *);
>  extern int	 journal_forget (handle_t *, struct buffer_head *);
>  extern void	 journal_sync_buffer (struct buffer_head *);
>  extern void	 journal_invalidatepage(journal_t *,
> -				struct page *, unsigned long);
> +				struct page *, unsigned int, unsigned int);
>  extern int	 journal_try_to_free_buffers(journal_t *, struct page *, gfp_t);
>  extern int	 journal_stop(handle_t *);
>  extern int	 journal_flush (journal_t *);
> diff --git a/include/trace/events/ext3.h b/include/trace/events/ext3.h
> index 15d11a3..6797b9d 100644
> --- a/include/trace/events/ext3.h
> +++ b/include/trace/events/ext3.h
> @@ -290,13 +290,14 @@ DEFINE_EVENT(ext3__page_op, ext3_releasepage,
>  );
>  
>  TRACE_EVENT(ext3_invalidatepage,
> -	TP_PROTO(struct page *page, unsigned long offset),
> +	TP_PROTO(struct page *page, unsigned int offset, unsigned int length),
>  
> -	TP_ARGS(page, offset),
> +	TP_ARGS(page, offset, length),
>  
>  	TP_STRUCT__entry(
>  		__field(	pgoff_t, index			)
> -		__field(	unsigned long, offset		)
> +		__field(	unsigned int, offset		)
> +		__field(	unsigned int, length		)
>  		__field(	ino_t,	ino			)
>  		__field(	dev_t,	dev			)
>  
> @@ -305,14 +306,15 @@ TRACE_EVENT(ext3_invalidatepage,
>  	TP_fast_assign(
>  		__entry->index	= page->index;
>  		__entry->offset	= offset;
> +		__entry->length	= length;
>  		__entry->ino	= page->mapping->host->i_ino;
>  		__entry->dev	= page->mapping->host->i_sb->s_dev;
>  	),
>  
> -	TP_printk("dev %d,%d ino %lu page_index %lu offset %lu",
> +	TP_printk("dev %d,%d ino %lu page_index %lu offset %u length %u",
>  		  MAJOR(__entry->dev), MINOR(__entry->dev),
>  		  (unsigned long) __entry->ino,
> -		  __entry->index, __entry->offset)
> +		  __entry->index, __entry->offset, __entry->length)
>  );
>  
>  TRACE_EVENT(ext3_discard_blocks,
> -- 
> 1.7.7.6
> 
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-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

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