Btrfs devel - Mar 2010 - [PATCH 09/18] btrfs: Fix return value of read_extent_buffer_pages() when lock page failed

From: Zhao Lei <zhaolei@cn.fujitsu.com>

read_extent_buffer_pages() should return error value instead of 0 when
lock page failed, we fix this problem.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
---
 fs/btrfs/extent_io.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index bdfbfa6..3194c79 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3419,8 +3419,10 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
 	for (i = start_i; i < num_pages; i++) {
 		page = extent_buffer_page(eb, i);
 		if (!wait) {
-			if (!trylock_page(page))
+			if (!trylock_page(page)) {
+				ret = -EIO;
 				goto unlock_exit;
+			}
 		} else {
 			lock_page(page);
 		}
-- 
1.6.5.2


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On Thu, Mar 25, 2010 at 08:33:27PM +0800, Miao Xie
wrote:
> From: Zhao Lei <zhaolei@cn.fujitsu.com>
> 
> read_extent_buffer_pages() should return error value instead of 0 when
> lock page failed, we fix this problem.
[ Thanks for all of these patches! ]

This isn''t strictly an IO error, the caller has said they are not
willing to wait, so we don''t wait.  That''s different from
finding a page
where the IO had failed.

In general we ignore the errors until the caller is willing to wait for
the result.

-chris
> 
> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
> ---
>  fs/btrfs/extent_io.c |    4 +++-
>  1 files changed, 3 insertions(+), 1 deletions(-)
> 
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index bdfbfa6..3194c79 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -3419,8 +3419,10 @@ int read_extent_buffer_pages(struct extent_io_tree
*tree,
>  	for (i = start_i; i < num_pages; i++) {
>  		page = extent_buffer_page(eb, i);
>  		if (!wait) {
> -			if (!trylock_page(page))
> +			if (!trylock_page(page)) {
> +				ret = -EIO;
>  				goto unlock_exit;
> +			}
>  		} else {
>  			lock_page(page);
>  		}
> -- 
> 1.6.5.2
> 
> 
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Chris Mason wrote:
> On Thu, Mar 25, 2010 at 08:33:27PM +0800, Miao Xie wrote:
>> From: Zhao Lei <zhaolei@cn.fujitsu.com>
>>
>> read_extent_buffer_pages() should return error value instead of 0 when
>> lock page failed, we fix this problem.
> 
> [ Thanks for all of these patches! ]
> 
> This isn''t strictly an IO error, the caller has said they are not
> willing to wait, so we don''t wait.  That''s different from
finding a page
> where the IO had failed.
> 
> In general we ignore the errors until the caller is willing to wait for
> the result.
> 
> -chris
Hello, chris

Thanks for your response.
I''ll drop this patch.

Thanks
Zhaolei
>> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
>> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
>> ---
>>  fs/btrfs/extent_io.c |    4 +++-
>>  1 files changed, 3 insertions(+), 1 deletions(-)
>>
>> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
>> index bdfbfa6..3194c79 100644
>> --- a/fs/btrfs/extent_io.c
>> +++ b/fs/btrfs/extent_io.c
>> @@ -3419,8 +3419,10 @@ int read_extent_buffer_pages(struct
extent_io_tree *tree,
>>  	for (i = start_i; i < num_pages; i++) {
>>  		page = extent_buffer_page(eb, i);
>>  		if (!wait) {
>> -			if (!trylock_page(page))
>> +			if (!trylock_page(page)) {
>> +				ret = -EIO;
>>  				goto unlock_exit;
>> +			}
>>  		} else {
>>  			lock_page(page);
>>  		}
>> -- 
>> 1.6.5.2
>>
>>
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linux-btrfs" in
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