[v2,1/3] fs: remove redundant cache invalidation after async direct-io write
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Message ID 157270037850.4812.15036239021726025572.stgit@buzz
State New
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Series
  • [v2,1/3] fs: remove redundant cache invalidation after async direct-io write
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Commit Message

Konstantin Khlebnikov Nov. 2, 2019, 1:12 p.m. UTC
Function generic_file_direct_write() invalidates cache at entry. Second
time this should be done when request completes. But this function calls
second invalidation at exit unconditionally even for async requests.

This patch skips second invalidation for async requests (-EIOCBQUEUED).

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
---
 mm/filemap.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Comments

Jan Kara Nov. 21, 2019, 4:21 p.m. UTC | #1
On Sat 02-11-19 16:12:58, Konstantin Khlebnikov wrote:
> Function generic_file_direct_write() invalidates cache at entry. Second
> time this should be done when request completes. But this function calls
> second invalidation at exit unconditionally even for async requests.
> 
> This patch skips second invalidation for async requests (-EIOCBQUEUED).
> 
> Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>

Looks good to me. You can add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  mm/filemap.c |    6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 85b7d087eb45..288e38199068 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -3218,9 +3218,11 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
>  	 * Most of the time we do not need this since dio_complete() will do
>  	 * the invalidation for us. However there are some file systems that
>  	 * do not end up with dio_complete() being called, so let's not break
> -	 * them by removing it completely
> +	 * them by removing it completely.
> +	 *
> +	 * Skip invalidation for async writes or if mapping has no pages.
>  	 */
> -	if (mapping->nrpages)
> +	if (written > 0 && mapping->nrpages)
>  		invalidate_inode_pages2_range(mapping,
>  					pos >> PAGE_SHIFT, end);
>  
>

Patch
diff mbox series

diff --git a/mm/filemap.c b/mm/filemap.c
index 85b7d087eb45..288e38199068 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3218,9 +3218,11 @@  generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
 	 * Most of the time we do not need this since dio_complete() will do
 	 * the invalidation for us. However there are some file systems that
 	 * do not end up with dio_complete() being called, so let's not break
-	 * them by removing it completely
+	 * them by removing it completely.
+	 *
+	 * Skip invalidation for async writes or if mapping has no pages.
 	 */
-	if (mapping->nrpages)
+	if (written > 0 && mapping->nrpages)
 		invalidate_inode_pages2_range(mapping,
 					pos >> PAGE_SHIFT, end);