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Message-ID: <alpine.LFD.2.00.1310071717550.1975@localhost.localdomain>
Date:	Mon, 7 Oct 2013 17:30:17 +0200 (CEST)
From:	Lukáš Czerner <lczerner@...hat.com>
To:	"Darrick J. Wong" <darrick.wong@...cle.com>
cc:	tytso@....edu, linux-ext4@...r.kernel.org
Subject: Re: [PATCH 15/31] e2fsck: Teach EA refcounting code to handle 48bit
 block addresses

On Mon, 30 Sep 2013, Darrick J. Wong wrote:

> Date: Mon, 30 Sep 2013 18:28:18 -0700
> From: Darrick J. Wong <darrick.wong@...cle.com>
> To: tytso@....edu, darrick.wong@...cle.com
> Cc: linux-ext4@...r.kernel.org
> Subject: [PATCH 15/31] e2fsck: Teach EA refcounting code to handle 48bit block
>      addresses

Did you meant to say 64bit ?

> 
> The extended attribute refcounting code only accepts blk_t, which is dangerous
> because EA blocks can exist at high addresses (> 2^32) as well.  Therefore,
> widen the block fields to 64 bits.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com>
> ---
>  e2fsck/e2fsck.h      |   12 ++++++------
>  e2fsck/ea_refcount.c |   36 ++++++++++++++++++------------------
>  2 files changed, 24 insertions(+), 24 deletions(-)
> 
> 
> diff --git a/e2fsck/e2fsck.h b/e2fsck/e2fsck.h
> index 13d70f1..f1df525 100644
> --- a/e2fsck/e2fsck.h
> +++ b/e2fsck/e2fsck.h
> @@ -432,17 +432,17 @@ extern struct dx_dir_info *e2fsck_dx_dir_info_iter(e2fsck_t ctx, int *control);
>  /* ea_refcount.c */
>  extern errcode_t ea_refcount_create(int size, ext2_refcount_t *ret);
>  extern void ea_refcount_free(ext2_refcount_t refcount);
> -extern errcode_t ea_refcount_fetch(ext2_refcount_t refcount, blk_t blk,
> +extern errcode_t ea_refcount_fetch(ext2_refcount_t refcount, blk64_t blk,
>  				   int *ret);
>  extern errcode_t ea_refcount_increment(ext2_refcount_t refcount,
> -				       blk_t blk, int *ret);
> +				       blk64_t blk, int *ret);
>  extern errcode_t ea_refcount_decrement(ext2_refcount_t refcount,
> -				       blk_t blk, int *ret);
> +				       blk64_t blk, int *ret);
>  extern errcode_t ea_refcount_store(ext2_refcount_t refcount,
> -				   blk_t blk, int count);
> -extern blk_t ext2fs_get_refcount_size(ext2_refcount_t refcount);
> +				   blk64_t blk, int count);
> +extern blk64_t ext2fs_get_refcount_size(ext2_refcount_t refcount);
>  extern void ea_refcount_intr_begin(ext2_refcount_t refcount);
> -extern blk_t ea_refcount_intr_next(ext2_refcount_t refcount, int *ret);
> +extern blk64_t ea_refcount_intr_next(ext2_refcount_t refcount, int *ret);
>  
>  /* ehandler.c */
>  extern const char *ehandler_operation(const char *op);
> diff --git a/e2fsck/ea_refcount.c b/e2fsck/ea_refcount.c
> index e66e636..bcce6a0 100644
> --- a/e2fsck/ea_refcount.c
> +++ b/e2fsck/ea_refcount.c
> @@ -25,14 +25,14 @@
>   * checked, its bit is set in the block_ea_map bitmap.
>   */
>  struct ea_refcount_el {
> -	blk_t	ea_blk;
> +	blk64_t	ea_blk;
>  	int	ea_count;
>  };
>  
>  struct ea_refcount {
> -	blk_t		count;
> -	blk_t		size;
> -	blk_t		cursor;
> +	blk64_t		count;
> +	blk64_t		size;
> +	blk64_t		cursor;

I am not sure if we really need count, size and cursor to be blk_t
let alone blk64_t. It's a bit misleading because AFAICT those
variable does not represent block numbers at all. Maybe it should be
changed to something less confusing, preferably matching the actual
xattr implementation ?

Thanks!
-Lukas

>  	struct ea_refcount_el	*list;
>  };
>  
> @@ -111,11 +111,11 @@ static void refcount_collapse(ext2_refcount_t refcount)
>   * 	specified position.
>   */
>  static struct ea_refcount_el *insert_refcount_el(ext2_refcount_t refcount,
> -						 blk_t blk, int pos)
> +						 blk64_t blk, int pos)
>  {
>  	struct ea_refcount_el 	*el;
>  	errcode_t		retval;
> -	blk_t			new_size = 0;
> +	blk64_t			new_size = 0;
>  	int			num;
>  
>  	if (refcount->count >= refcount->size) {
> @@ -153,7 +153,7 @@ static struct ea_refcount_el *insert_refcount_el(ext2_refcount_t refcount,
>   * 	and we can't find an entry, create one in the sorted list.
>   */
>  static struct ea_refcount_el *get_refcount_el(ext2_refcount_t refcount,
> -					      blk_t blk, int create)
> +					      blk64_t blk, int create)
>  {
>  	int	low, high, mid;
>  
> @@ -206,7 +206,7 @@ retry:
>  	return 0;
>  }
>  
> -errcode_t ea_refcount_fetch(ext2_refcount_t refcount, blk_t blk,
> +errcode_t ea_refcount_fetch(ext2_refcount_t refcount, blk64_t blk,
>  				int *ret)
>  {
>  	struct ea_refcount_el	*el;
> @@ -220,7 +220,7 @@ errcode_t ea_refcount_fetch(ext2_refcount_t refcount, blk_t blk,
>  	return 0;
>  }
>  
> -errcode_t ea_refcount_increment(ext2_refcount_t refcount, blk_t blk, int *ret)
> +errcode_t ea_refcount_increment(ext2_refcount_t refcount, blk64_t blk, int *ret)
>  {
>  	struct ea_refcount_el	*el;
>  
> @@ -234,7 +234,7 @@ errcode_t ea_refcount_increment(ext2_refcount_t refcount, blk_t blk, int *ret)
>  	return 0;
>  }
>  
> -errcode_t ea_refcount_decrement(ext2_refcount_t refcount, blk_t blk, int *ret)
> +errcode_t ea_refcount_decrement(ext2_refcount_t refcount, blk64_t blk, int *ret)
>  {
>  	struct ea_refcount_el	*el;
>  
> @@ -249,7 +249,7 @@ errcode_t ea_refcount_decrement(ext2_refcount_t refcount, blk_t blk, int *ret)
>  	return 0;
>  }
>  
> -errcode_t ea_refcount_store(ext2_refcount_t refcount, blk_t blk, int count)
> +errcode_t ea_refcount_store(ext2_refcount_t refcount, blk64_t blk, int count)
>  {
>  	struct ea_refcount_el	*el;
>  
> @@ -263,7 +263,7 @@ errcode_t ea_refcount_store(ext2_refcount_t refcount, blk_t blk, int count)
>  	return 0;
>  }
>  
> -blk_t ext2fs_get_refcount_size(ext2_refcount_t refcount)
> +blk64_t ext2fs_get_refcount_size(ext2_refcount_t refcount)
>  {
>  	if (!refcount)
>  		return 0;
> @@ -277,7 +277,7 @@ void ea_refcount_intr_begin(ext2_refcount_t refcount)
>  }
>  
>  
> -blk_t ea_refcount_intr_next(ext2_refcount_t refcount,
> +blk64_t ea_refcount_intr_next(ext2_refcount_t refcount,
>  				int *ret)
>  {
>  	struct ea_refcount_el	*list;
> @@ -370,7 +370,7 @@ int main(int argc, char **argv)
>  	int	i = 0;
>  	ext2_refcount_t refcount;
>  	int		size, arg;
> -	blk_t		blk;
> +	blk64_t		blk;
>  	errcode_t	retval;
>  
>  	while (1) {
> @@ -394,7 +394,7 @@ int main(int argc, char **argv)
>  			printf("Freeing refcount\n");
>  			break;
>  		case BCODE_STORE:
> -			blk = (blk_t) bcode_program[i++];
> +			blk = (blk64_t) bcode_program[i++];
>  			arg = bcode_program[i++];
>  			printf("Storing blk %u with value %d\n", blk, arg);
>  			retval = ea_refcount_store(refcount, blk, arg);
> @@ -403,7 +403,7 @@ int main(int argc, char **argv)
>  					"while storing blk %u", blk);
>  			break;
>  		case BCODE_FETCH:
> -			blk = (blk_t) bcode_program[i++];
> +			blk = (blk64_t) bcode_program[i++];
>  			retval = ea_refcount_fetch(refcount, blk, &arg);
>  			if (retval)
>  				com_err("ea_refcount_fetch", retval,
> @@ -413,7 +413,7 @@ int main(int argc, char **argv)
>  				       blk, arg);
>  			break;
>  		case BCODE_INCR:
> -			blk = (blk_t) bcode_program[i++];
> +			blk = (blk64_t) bcode_program[i++];
>  			retval = ea_refcount_increment(refcount, blk, &arg);
>  			if (retval)
>  				com_err("ea_refcount_increment", retval,
> @@ -423,7 +423,7 @@ int main(int argc, char **argv)
>  				       blk, arg);
>  			break;
>  		case BCODE_DECR:
> -			blk = (blk_t) bcode_program[i++];
> +			blk = (blk64_t) bcode_program[i++];
>  			retval = ea_refcount_decrement(refcount, blk, &arg);
>  			if (retval)
>  				com_err("ea_refcount_decrement", retval,
> 
> --
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