[dm-devel] GFP_KERNEL in ext4 (was: [PATCH 4/4] Support discard if at least one underlying device supports it)

[Mikulas Patocka]

> ---
>  include/linux/blkdev.h |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> Index: linux-2.6.35-rc3-fast/include/linux/blkdev.h
> ===================================================================
> --- linux-2.6.35-rc3-fast.orig/include/linux/blkdev.h	2010-07-02 21:59:21.000000000 +0200
> +++ linux-2.6.35-rc3-fast/include/linux/blkdev.h	2010-07-02 21:59:37.000000000 +0200
> @@ -1021,7 +1021,7 @@ static inline int sb_issue_discard(struc
>  	block <<= (sb->s_blocksize_bits - 9);
>  	nr_blocks <<= (sb->s_blocksize_bits - 9);
>  	return blkdev_issue_discard(sb->s_bdev, block, nr_blocks, GFP_KERNEL,
> 				   BLKDEV_IFL_WAIT | BLKDEV_IFL_BARRIER);
>  }
>  
>  extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
> 

A note for ext4 developers: is that GFP_KERNEL safe? Can't it recurse back 
to ext4 and attempt to flush more data?

I'm not familiar enough with ext4 to declare that it is/isn't a bug, but 
it looks suspicious.

Mikulas