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* [PATCH] quota: add missing use of dq_data_lock in __dquot_initialize
@ 2013-02-27 19:43 Jeff Mahoney
  2013-03-01  9:35 ` Jan Kara
  0 siblings, 1 reply; 2+ messages in thread
From: Jeff Mahoney @ 2013-02-27 19:43 UTC (permalink / raw)
  To: Linux FS Maling List; +Cc: Jan Kara

The bulk of __dquot_initialize runs under the dqptr_sem which
protects the inode->i_dquot pointers. It doesn't protect the
dereferenced contents, though. Those are protected by the
dq_data_lock, which is missing around the dquot_resv_space call.

Cc: Jan Kara <jack@suse.com>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
--

 fs/quota/dquot.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -1439,8 +1439,11 @@ static void __dquot_initialize(struct in
 			 * did a write before quota was turned on
 			 */
 			rsv = inode_get_rsv_space(inode);
-			if (unlikely(rsv))
+			if (unlikely(rsv)) {
+				spin_lock(&dq_data_lock);
 				dquot_resv_space(inode->i_dquot[cnt], rsv);
+				spin_unlock(&dq_data_lock);
+			}
 		}
 	}
 out_err:

-- 
Jeff Mahoney
SUSE Labs

^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH] quota: add missing use of dq_data_lock in __dquot_initialize
  2013-02-27 19:43 [PATCH] quota: add missing use of dq_data_lock in __dquot_initialize Jeff Mahoney
@ 2013-03-01  9:35 ` Jan Kara
  0 siblings, 0 replies; 2+ messages in thread
From: Jan Kara @ 2013-03-01  9:35 UTC (permalink / raw)
  To: Jeff Mahoney; +Cc: Linux FS Maling List, Jan Kara

On Wed 27-02-13 14:43:09, Jeff Mahoney wrote:
> The bulk of __dquot_initialize runs under the dqptr_sem which
> protects the inode->i_dquot pointers. It doesn't protect the
> dereferenced contents, though. Those are protected by the
> dq_data_lock, which is missing around the dquot_resv_space call.
> 
> Cc: Jan Kara <jack@suse.com>
> Signed-off-by: Jeff Mahoney <jeffm@suse.com>
  Thanks! I've merged the patch. Just one small nitpick - git(1) expects
diffstat to be separated by three dashes (not two) so I had to fix that up
so that it doesn't appear in the commit message. Not sure how that happened
in your submission but I wanted to point that out just in case it was some
systematic error...

								Honza
> --
> 
>  fs/quota/dquot.c |    5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> --- a/fs/quota/dquot.c
> +++ b/fs/quota/dquot.c
> @@ -1439,8 +1439,11 @@ static void __dquot_initialize(struct in
>  			 * did a write before quota was turned on
>  			 */
>  			rsv = inode_get_rsv_space(inode);
> -			if (unlikely(rsv))
> +			if (unlikely(rsv)) {
> +				spin_lock(&dq_data_lock);
>  				dquot_resv_space(inode->i_dquot[cnt], rsv);
> +				spin_unlock(&dq_data_lock);
> +			}
>  		}
>  	}
>  out_err:
> 
> -- 
> Jeff Mahoney
> SUSE Labs
> --
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-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

^ permalink raw reply	[flat|nested] 2+ messages in thread

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