diff mbox

[v2] Btrfs: fix unexpected balance crash due to BUG_ON

Message ID 1468257695-22445-1-git-send-email-bo.li.liu@oracle.com (mailing list archive)
State Superseded
Headers show

Commit Message

Liu Bo July 11, 2016, 5:21 p.m. UTC
Mounting a btrfs can resume previous balance operations asynchronously.
An user got a crash when one drive has some corrupt sectors.

Since balance can cancel itself in case of any error, we can gracefully
return errors to upper layers and let balance do the cancel job.

Reported-by: sash <master.b.at.raven@chefmail.de>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
---
v2: - Initialize path with NULL.
    - Show more information when we bail out.

 fs/btrfs/volumes.c | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

Comments

Chris Mason July 11, 2016, 8:39 p.m. UTC | #1
On 07/11/2016 01:21 PM, Liu Bo wrote:
> Mounting a btrfs can resume previous balance operations asynchronously.
> An user got a crash when one drive has some corrupt sectors.
>
> Since balance can cancel itself in case of any error, we can gracefully
> return errors to upper layers and let balance do the cancel job.
>
> Reported-by: sash <master.b.at.raven@chefmail.de>
> Signed-off-by: Liu Bo <bo.li.liu@oracle.com>

v2 Looks good, thanks Liu.

Signed-off-by: Chris Mason <clm@fb.com>
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Filipe Manana July 12, 2016, 8:45 a.m. UTC | #2
On Mon, Jul 11, 2016 at 6:21 PM, Liu Bo <bo.li.liu@oracle.com> wrote:
> Mounting a btrfs can resume previous balance operations asynchronously.
> An user got a crash when one drive has some corrupt sectors.
>
> Since balance can cancel itself in case of any error, we can gracefully
> return errors to upper layers and let balance do the cancel job.
>
> Reported-by: sash <master.b.at.raven@chefmail.de>
> Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
> ---
> v2: - Initialize path with NULL.
>     - Show more information when we bail out.
>
>  fs/btrfs/volumes.c | 30 ++++++++++++++++++++++++++----
>  1 file changed, 26 insertions(+), 4 deletions(-)
>
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index 589f128..348a183 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -3421,7 +3421,7 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
>         u64 size_to_free;
>         u64 chunk_type;
>         struct btrfs_chunk *chunk;
> -       struct btrfs_path *path;
> +       struct btrfs_path *path = NULL;
>         struct btrfs_key key;
>         struct btrfs_key found_key;
>         struct btrfs_trans_handle *trans;
> @@ -3455,13 +3455,35 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
>                 ret = btrfs_shrink_device(device, old_size - size_to_free);
>                 if (ret == -ENOSPC)
>                         break;
> -               BUG_ON(ret);
> +               if (ret) {
> +                       /* btrfs_shrink_device never returns ret > 0 */
> +                       WARN_ON(ret > 0);
> +                       goto error;
> +               }
>
>                 trans = btrfs_start_transaction(dev_root, 0);
> -               BUG_ON(IS_ERR(trans));
> +               if (IS_ERR(trans)) {
> +                       ret = PTR_ERR(trans);
> +                       btrfs_info(fs_info,
> +                "%s:%d fails on btrfs_start_transaction() right after shrinking devivce %s (original size is %llu new size is %llu",

devivce -> device

> +                                  __func__, __LINE__,
> +                                  rcu_str_deref(device->name), old_size,
> +                                  old_size - size_to_free);
> +                       goto error;
> +               }
>
>                 ret = btrfs_grow_device(trans, device, old_size);
> -               BUG_ON(ret);
> +               if (ret) {
> +                       btrfs_end_transaction(trans, dev_root);
> +                       /* btrfs_grow_device never returns ret > 0 */
> +                       WARN_ON(ret > 0);
> +                       btrfs_info(fs_info,
> +                "%s:%d fails on btrfs_grow_device() right after shrinking devivce %s (original size is %llu new size is %llu",

devivce -> device

> +                                  __func__, __LINE__,
> +                                  rcu_str_deref(device->name), old_size,
> +                                  old_size - size_to_free);
> +                       goto error;
> +               }
>
>                 btrfs_end_transaction(trans, dev_root);
>         }
> --
> 2.5.5
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
David Sterba July 12, 2016, 12:02 p.m. UTC | #3
On Mon, Jul 11, 2016 at 10:21:35AM -0700, Liu Bo wrote:
> +		}
>  
>  		trans = btrfs_start_transaction(dev_root, 0);
> -		BUG_ON(IS_ERR(trans));
> +		if (IS_ERR(trans)) {
> +			ret = PTR_ERR(trans);
> +			btrfs_info(fs_info,

This could be btrfs_info_in_rcu for clarity (using the rcu_string)

> +		 "%s:%d fails on btrfs_start_transaction() right after shrinking devivce %s (original size is %llu new size is %llu",
> +				   __func__, __LINE__,

I'm not sure the function and line is necessary, we don't use it
anywhere else. I'd suggest a slight modification:

		"resize: unable to start transaction after shrinking device %s (error %d), old size %llu, new size %llu"

> +				   rcu_str_deref(device->name), old_size,
> +				   old_size - size_to_free);
> +			goto error;
> +		}
>  
>  		ret = btrfs_grow_device(trans, device, old_size);
> -		BUG_ON(ret);
> +		if (ret) {
> +			btrfs_end_transaction(trans, dev_root);
> +			/* btrfs_grow_device never returns ret > 0 */
> +			WARN_ON(ret > 0);
> +			btrfs_info(fs_info,
> +		 "%s:%d fails on btrfs_grow_device() right after shrinking devivce %s (original size is %llu new size is %llu",

"resize: unable to grow device after shrinking device %s (error %d), old size %llu, new size %llu"
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
diff mbox

Patch

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 589f128..348a183 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3421,7 +3421,7 @@  static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 	u64 size_to_free;
 	u64 chunk_type;
 	struct btrfs_chunk *chunk;
-	struct btrfs_path *path;
+	struct btrfs_path *path = NULL;
 	struct btrfs_key key;
 	struct btrfs_key found_key;
 	struct btrfs_trans_handle *trans;
@@ -3455,13 +3455,35 @@  static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 		ret = btrfs_shrink_device(device, old_size - size_to_free);
 		if (ret == -ENOSPC)
 			break;
-		BUG_ON(ret);
+		if (ret) {
+			/* btrfs_shrink_device never returns ret > 0 */
+			WARN_ON(ret > 0);
+			goto error;
+		}
 
 		trans = btrfs_start_transaction(dev_root, 0);
-		BUG_ON(IS_ERR(trans));
+		if (IS_ERR(trans)) {
+			ret = PTR_ERR(trans);
+			btrfs_info(fs_info,
+		 "%s:%d fails on btrfs_start_transaction() right after shrinking devivce %s (original size is %llu new size is %llu",
+				   __func__, __LINE__,
+				   rcu_str_deref(device->name), old_size,
+				   old_size - size_to_free);
+			goto error;
+		}
 
 		ret = btrfs_grow_device(trans, device, old_size);
-		BUG_ON(ret);
+		if (ret) {
+			btrfs_end_transaction(trans, dev_root);
+			/* btrfs_grow_device never returns ret > 0 */
+			WARN_ON(ret > 0);
+			btrfs_info(fs_info,
+		 "%s:%d fails on btrfs_grow_device() right after shrinking devivce %s (original size is %llu new size is %llu",
+				   __func__, __LINE__,
+				   rcu_str_deref(device->name), old_size,
+				   old_size - size_to_free);
+			goto error;
+		}
 
 		btrfs_end_transaction(trans, dev_root);
 	}