[PATCH] xfs_io: Improvements to copy_range return code handling

[PATCH] xfs_io: Improvements to copy_range return code handling

[Anna Schumaker]

If copy_file_range() returns 0, then that means no data was copied.  We
should break out of the loop in this case to prevent looping
indefinitely.

Additionally, if an error is returned by copy_file_range() then we need
to print out the string form to be used by error checking tests in
xfstests.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
---
 io/copy_file_range.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/io/copy_file_range.c b/io/copy_file_range.c
index eddc634..161bdcf 100644
--- a/io/copy_file_range.c
+++ b/io/copy_file_range.c
@@ -49,8 +49,11 @@ copy_file_range(int fd, loff_t *src, loff_t *dst, size_t len)
 
 	do {
 		ret = syscall(__NR_copy_file_range, fd, src, file->fd, dst, len, 0);
-		if (ret == -1)
+		if (ret == -1) {
+			fprintf(stderr, _("copy_range: %s\n"), strerror(errno));
 			return errno;
+		} else if (ret == 0)
+			break;
 		len -= ret;
 	} while (len > 0);
 
-- 
2.10.2

Re: [PATCH] xfs_io: Improvements to copy_range return code handling

[Dave Chinner]

On Thu, Dec 08, 2016 at 01:44:47PM -0500, Anna Schumaker wrote:
> If copy_file_range() returns 0, then that means no data was copied.  We
> should break out of the loop in this case to prevent looping
> indefinitely.
> 
> Additionally, if an error is returned by copy_file_range() then we need
> to print out the string form to be used by error checking tests in
> xfstests.
> 
> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
> ---
>  io/copy_file_range.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/io/copy_file_range.c b/io/copy_file_range.c
> index eddc634..161bdcf 100644
> --- a/io/copy_file_range.c
> +++ b/io/copy_file_range.c
> @@ -49,8 +49,11 @@ copy_file_range(int fd, loff_t *src, loff_t *dst, size_t len)
>  
>  	do {
>  		ret = syscall(__NR_copy_file_range, fd, src, file->fd, dst, len, 0);
> -		if (ret == -1)
> +		if (ret == -1) {
> +			fprintf(stderr, _("copy_range: %s\n"), strerror(errno));

perror("copy_range")?

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com