Re: [PATCH 1/2] btrfs: Remove invalid null checks from btrfs_cleanup_dirty_bgs

2018-02-13 Thread David Sterba 
On Thu, Feb 08, 2018 at 10:57:11AM -0800, Liu Bo wrote:
> On Thu, Feb 08, 2018 at 06:25:17PM +0200, Nikolay Borisov wrote:
> > list_first_entry is essentially a wrapper over cotnainer_of. The latter
> > can never return null even if it's working on inconsistent list since it
> > will either crash or return some offset in the wrong struct.
> > Additionally, for the dirty_bgs list the iteration is done under
> > dirty_bgs_lock which ensures consistency of the list.
> > 
> 
> Reviewed-by: Liu Bo 

Added to next, thanks.
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Re: [PATCH 1/2] btrfs: Remove invalid null checks from btrfs_cleanup_dirty_bgs

2018-02-08 Thread Liu Bo 
On Thu, Feb 08, 2018 at 06:25:17PM +0200, Nikolay Borisov wrote:
> list_first_entry is essentially a wrapper over cotnainer_of. The latter
> can never return null even if it's working on inconsistent list since it
> will either crash or return some offset in the wrong struct.
> Additionally, for the dirty_bgs list the iteration is done under
> dirty_bgs_lock which ensures consistency of the list.
> 

Reviewed-by: Liu Bo 

-liubo

> Signed-off-by: Nikolay Borisov 
> ---
>  fs/btrfs/disk-io.c | 9 -
>  1 file changed, 9 deletions(-)
> 
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index aca906971abe..1b3989c54d7c 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -4323,11 +4323,6 @@ void btrfs_cleanup_dirty_bgs(struct btrfs_transaction 
> *cur_trans,
>   cache = list_first_entry(&cur_trans->dirty_bgs,
>struct btrfs_block_group_cache,
>dirty_list);
> - if (!cache) {
> - btrfs_err(fs_info, "orphan block group dirty_bgs list");
> - spin_unlock(&cur_trans->dirty_bgs_lock);
> - return;
> - }
>  
>   if (!list_empty(&cache->io_list)) {
>   spin_unlock(&cur_trans->dirty_bgs_lock);
> @@ -4351,10 +4346,6 @@ void btrfs_cleanup_dirty_bgs(struct btrfs_transaction 
> *cur_trans,
>   cache = list_first_entry(&cur_trans->io_bgs,
>struct btrfs_block_group_cache,
>io_list);
> - if (!cache) {
> - btrfs_err(fs_info, "orphan block group on io_bgs list");
> - return;
> - }
>  
>   list_del_init(&cache->io_list);
>   spin_lock(&cache->lock);
> -- 
> 2.7.4
> 
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[PATCH 1/2] btrfs: Remove invalid null checks from btrfs_cleanup_dirty_bgs

2018-02-08 Thread Nikolay Borisov 
list_first_entry is essentially a wrapper over cotnainer_of. The latter
can never return null even if it's working on inconsistent list since it
will either crash or return some offset in the wrong struct.
Additionally, for the dirty_bgs list the iteration is done under
dirty_bgs_lock which ensures consistency of the list.

Signed-off-by: Nikolay Borisov 
---
 fs/btrfs/disk-io.c | 9 -
 1 file changed, 9 deletions(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index aca906971abe..1b3989c54d7c 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -4323,11 +4323,6 @@ void btrfs_cleanup_dirty_bgs(struct btrfs_transaction 
*cur_trans,
cache = list_first_entry(&cur_trans->dirty_bgs,
 struct btrfs_block_group_cache,
 dirty_list);
-   if (!cache) {
-   btrfs_err(fs_info, "orphan block group dirty_bgs list");
-   spin_unlock(&cur_trans->dirty_bgs_lock);
-   return;
-   }
 
if (!list_empty(&cache->io_list)) {
spin_unlock(&cur_trans->dirty_bgs_lock);
@@ -4351,10 +4346,6 @@ void btrfs_cleanup_dirty_bgs(struct btrfs_transaction 
*cur_trans,
cache = list_first_entry(&cur_trans->io_bgs,
 struct btrfs_block_group_cache,
 io_list);
-   if (!cache) {
-   btrfs_err(fs_info, "orphan block group on io_bgs list");
-   return;
-   }
 
list_del_init(&cache->io_list);
spin_lock(&cache->lock);
-- 
2.7.4

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