Ocfs2 devel - May 2020 - [PATCH 1/2] ocfs2: clear links count in ocfs2_mknod() if an error occurs

In this condition, the inode can not be wiped when error happened.
ocfs2_mkdir()
  ->ocfs2_mknod()
    ->ocfs2_mknod_locked()
      ->__ocfs2_mknod_locked()
        ->ocfs2_set_links_count() // i_links_count is 2
    -> ... // an error accrue, goto roll_back or leave.
    ->ocfs2_commit_trans()
    ->iput(inode)
      ->evict()
        ->ocfs2_evict_inode()
          ->ocfs2_delete_inode()
            ->ocfs2_inode_lock()
              ->ocfs2_inode_lock_update()
                ->ocfs2_refresh_inode()
                  ->set_nlink();    // inode->i_nlink is 2 now.
            /* if wipe is 0, it will goto bail_unlock_inode */
            ->ocfs2_query_inode_wipe()
              ->if (inode->i_nlink) return; // wipe is 0.
            /* inode can not be wiped */
            ->ocfs2_wipe_inode()
So, we need clear links before the transaction committed.

Signed-off-by: Yan Wang <wangyan122 at huawei.com>
Reviewed-by: Jun Piao <piaojun at huawei.com>
---
 fs/ocfs2/namei.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
index 5381020aaa9a..e61fdd8972ec 100644
--- a/fs/ocfs2/namei.c
+++ b/fs/ocfs2/namei.c
@@ -453,8 +453,12 @@ static int ocfs2_mknod(struct inode *dir,
 leave:
 	if (status < 0 && did_quota_inode)
 		dquot_free_inode(inode);
-	if (handle)
+	if (handle) {
+		if (status < 0 && new_fe_bh != NULL)
+			ocfs2_set_links_count((struct ocfs2_dinode *)
+					new_fe_bh->b_data, 0);
 		ocfs2_commit_trans(osb, handle);
+	}

 	ocfs2_inode_unlock(dir, 1);
 	if (did_block_signals)
@@ -598,6 +602,8 @@ static int __ocfs2_mknod_locked(struct inode *dir,
 leave:
 	if (status < 0) {
 		if (*new_fe_bh) {
+			if (fe)
+				ocfs2_set_links_count(fe, 0);
 			brelse(*new_fe_bh);
 			*new_fe_bh = NULL;
 		}
@@ -2023,8 +2029,12 @@ static int ocfs2_symlink(struct inode *dir,
 					ocfs2_clusters_to_bytes(osb->sb, 1));
 	if (status < 0 && did_quota_inode)
 		dquot_free_inode(inode);
-	if (handle)
+	if (handle) {
+		if (status < 0 && new_fe_bh != NULL)
+			ocfs2_set_links_count((struct ocfs2_dinode *)
+					new_fe_bh->b_data, 0);
 		ocfs2_commit_trans(osb, handle);
+	}

 	ocfs2_inode_unlock(dir, 1);
 	if (did_block_signals)
-- 
2.23.0

On Tue, 26 May 2020 15:45:35 +0800 Wangyan <wangyan122 at huawei.com>
wrote:
> In this condition, the inode can not be wiped when error happened.
> ocfs2_mkdir()
>   ->ocfs2_mknod()
>     ->ocfs2_mknod_locked()
>       ->__ocfs2_mknod_locked()
>         ->ocfs2_set_links_count() // i_links_count is 2
>     -> ... // an error accrue, goto roll_back or leave.
>     ->ocfs2_commit_trans()
>     ->iput(inode)
>       ->evict()
>         ->ocfs2_evict_inode()
>           ->ocfs2_delete_inode()
>             ->ocfs2_inode_lock()
>               ->ocfs2_inode_lock_update()
>                 ->ocfs2_refresh_inode()
>                   ->set_nlink();    // inode->i_nlink is 2 now.
>             /* if wipe is 0, it will goto bail_unlock_inode */
>             ->ocfs2_query_inode_wipe()
>               ->if (inode->i_nlink) return; // wipe is 0.
>             /* inode can not be wiped */
>             ->ocfs2_wipe_inode()
> So, we need clear links before the transaction committed.
Do we think these fixes should be backported into -stable kernels?

Hi,

On 2020/5/26 15:45, Wangyan wrote:
> In this condition, the inode can not be wiped when error happened.
> ocfs2_mkdir()
>   ->ocfs2_mknod()
>     ->ocfs2_mknod_locked()
>       ->__ocfs2_mknod_locked()
>         ->ocfs2_set_links_count() // i_links_count is 2
>     -> ... // an error accrue, goto roll_back or leave.
>     ->ocfs2_commit_trans()
>     ->iput(inode)
>       ->evict()
>         ->ocfs2_evict_inode()
>           ->ocfs2_delete_inode()
>             ->ocfs2_inode_lock()
>               ->ocfs2_inode_lock_update()
>                 ->ocfs2_refresh_inode()
>                   ->set_nlink();    // inode->i_nlink is 2 now.
>             /* if wipe is 0, it will goto bail_unlock_inode */
>             ->ocfs2_query_inode_wipe()
>               ->if (inode->i_nlink) return; // wipe is 0.
>             /* inode can not be wiped */
>             ->ocfs2_wipe_inode()
> So, we need clear links before the transaction committed.
> 
> Signed-off-by: Yan Wang <wangyan122 at huawei.com>
> Reviewed-by: Jun Piao <piaojun at huawei.com>
> ---
>  fs/ocfs2/namei.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
> index 5381020aaa9a..e61fdd8972ec 100644
> --- a/fs/ocfs2/namei.c
> +++ b/fs/ocfs2/namei.c
> @@ -453,8 +453,12 @@ static int ocfs2_mknod(struct inode *dir,
>  leave:
>  	if (status < 0 && did_quota_inode)
>  		dquot_free_inode(inode);
> -	if (handle)
> +	if (handle) {
> +		if (status < 0 && new_fe_bh != NULL)
> +			ocfs2_set_links_count((struct ocfs2_dinode *)
> +					new_fe_bh->b_data, 0);
Seems no need to do this rollback under handle?
Only if (status < 0 && new_fe_bh) will be okay.
>  		ocfs2_commit_trans(osb, handle);
> +	}
> 
>  	ocfs2_inode_unlock(dir, 1);
>  	if (did_block_signals)
> @@ -598,6 +602,8 @@ static int __ocfs2_mknod_locked(struct inode *dir,
>  leave:
>  	if (status < 0) {
>  		if (*new_fe_bh) {
> +			if (fe)
> +				ocfs2_set_links_count(fe, 0);
Leave this to caller will be enough.

Thanks,
Joseph
>  			brelse(*new_fe_bh);>  			*new_fe_bh = NULL;
>  		}
> @@ -2023,8 +2029,12 @@ static int ocfs2_symlink(struct inode *dir,
>  					ocfs2_clusters_to_bytes(osb->sb, 1));
>  	if (status < 0 && did_quota_inode)
>  		dquot_free_inode(inode);
> -	if (handle)
> +	if (handle) {
> +		if (status < 0 && new_fe_bh != NULL)
> +			ocfs2_set_links_count((struct ocfs2_dinode *)
> +					new_fe_bh->b_data, 0);
>  		ocfs2_commit_trans(osb, handle);
> +	}
> 
>  	ocfs2_inode_unlock(dir, 1);
>  	if (did_block_signals)
>