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Re: [PATCH 1/3] xfs_repair: Fix fragmented multiblock dir2 handling in b

To: Eric Sandeen <sandeen@xxxxxxxxxx>
Subject: Re: [PATCH 1/3] xfs_repair: Fix fragmented multiblock dir2 handling in blkmap_getn()
From: Ben Myers <bpm@xxxxxxx>
Date: Thu, 31 May 2012 15:55:40 -0500
Cc: xfs-oss <xfs@xxxxxxxxxxx>
In-reply-to: <4FBABD3E.2050700@xxxxxxxxxx>
References: <4FBABCAB.20300@xxxxxxxxxx> <4FBABD3E.2050700@xxxxxxxxxx>
User-agent: Mutt/1.5.20 (2009-06-14)
Hey Eric,

On Mon, May 21, 2012 at 05:10:06PM -0500, Eric Sandeen wrote:
> blkmap_getn() contains a loop which populates an array of extents
> with mapping information for a dir2 "block," which may consist
> of multiple filesystem blocks.
> 
> As written, the loop re-allocates the array for each new extent,
> leaking the previously allocated memory and worse, losing the
> previously filled-in extent information.
> 
> Fix this by only allocating the array once, for the maximum
> possible number of extents - the number of fs blocks in the dir
> block.
> 
> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
> ---
> 
> diff --git a/repair/bmap.c b/repair/bmap.c
> index 2f1c307..c43ca7f 100644
> --- a/repair/bmap.c
> +++ b/repair/bmap.c
> @@ -168,7 +168,8 @@ blkmap_getn(
>               /*
>                * rare case - multiple extents for a single dir block
>                */
> -             bmp = malloc(nb * sizeof(bmap_ext_t));
> +             if (!bmp)
> +                     bmp = malloc(nb * sizeof(bmap_ext_t));

Cool.  That's an area where we don't have much test coverage.  I don't see a
single '-n size' in xfstests.

This looks good to me.  FWICS all the callers free it later.

Reviewed-by: Ben Myers <bpm@xxxxxxx>

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