[PATCH] Btrfs: fix btrfs_evict_inode to handle abnormal inodes correctly

[PATCH] Btrfs: fix btrfs_evict_inode to handle abnormal inodes correctly

[Liu Bo]

This regression is introduced in
commit 3d48d9810de4 ("btrfs: Handle uninitialised inode eviction").

There are two problems,

a) it is ->destroy_inode() that does the final free on inode, not
   ->evict_inode(),
b) clear_inode() must be called before ->evict_inode() returns.

This could end up hitting BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
in evict() because I_CLEAR is set in clear_inode().

Fixes: commit 3d48d9810de4 ("btrfs: Handle uninitialised inode eviction")
Cc: <stable@vger.kernel.org> # v4.7-rc6+
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
---
 fs/btrfs/inode.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 281a250..bc6ef73 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5286,7 +5286,7 @@ void btrfs_evict_inode(struct inode *inode)
 	trace_btrfs_inode_evict(inode);
 
 	if (!root) {
-		kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
+		clear_inode(inode);
 		return;
 	}
 
-- 
2.9.4

Re: [PATCH] Btrfs: fix btrfs_evict_inode to handle abnormal inodes correctly

[Nikolay Borisov]

On 25.01.2018 20:02, Liu Bo wrote:
> This regression is introduced in
> commit 3d48d9810de4 ("btrfs: Handle uninitialised inode eviction").
> 
> There are two problems,
> 
> a) it is ->destroy_inode() that does the final free on inode, not
>    ->evict_inode(),
> b) clear_inode() must be called before ->evict_inode() returns.
> 
> This could end up hitting BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
> in evict() because I_CLEAR is set in clear_inode().
> 

Oops, It seems I've missed that when I wrote the original patch.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>

> Fixes: commit 3d48d9810de4 ("btrfs: Handle uninitialised inode eviction")
> Cc: <stable@vger.kernel.org> # v4.7-rc6+
> Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
> ---
>  fs/btrfs/inode.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 281a250..bc6ef73 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -5286,7 +5286,7 @@ void btrfs_evict_inode(struct inode *inode)
>  	trace_btrfs_inode_evict(inode);
>  
>  	if (!root) {
> -		kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
> +		clear_inode(inode);
>  		return;
>  	}
>  
> 

Re: [PATCH] Btrfs: fix btrfs_evict_inode to handle abnormal inodes correctly

[Josef Bacik]

On Thu, Jan 25, 2018 at 11:02:53AM -0700, Liu Bo wrote:
> This regression is introduced in
> commit 3d48d9810de4 ("btrfs: Handle uninitialised inode eviction").
> 
> There are two problems,
> 
> a) it is ->destroy_inode() that does the final free on inode, not
>    ->evict_inode(),
> b) clear_inode() must be called before ->evict_inode() returns.
> 
> This could end up hitting BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
> in evict() because I_CLEAR is set in clear_inode().
> 
> Fixes: commit 3d48d9810de4 ("btrfs: Handle uninitialised inode eviction")
> Cc: <stable@vger.kernel.org> # v4.7-rc6+
> Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
> ---

Reviewed-by: Josef Bacik <jbacik@fb.com>

Thanks,

Josef