On Mon, Apr 10, 2017 at 03:47:53PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> The function block_to_bt plays an integral role in determining the btree
> geometry of a block that we want to manipulate with the debugger.
> Normally we use the block magic to find the geometry profile, but if the
> magic is bad we'll never find it and return NULL. The callers of this
> function do not check for NULL and crash.
>
> Therefore, if we can't find a geometry profile matching the magic
> number, use the iocursor type to guess the profile and scowl about that
> to stdout. This makes it so that even with a corrupt magic we can try
> to print the fields instead of crashing the debugger.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> v2: be less macro-happy and only evaluate hascrc once
> ---
> db/btblock.c | 52 ++++++++++++++++++++++++++++++++++++++++++++--------
> 1 file changed, 44 insertions(+), 8 deletions(-)
>
>
> diff --git a/db/btblock.c b/db/btblock.c
> index 835a5f0..e494f3e 100644
> --- a/db/btblock.c
> +++ b/db/btblock.c
> @@ -25,6 +25,8 @@
> #include "print.h"
> #include "bit.h"
> #include "init.h"
> +#include "io.h"
> +#include "output.h"
>
> /*
> * Definition of the possible btree block layouts.
> @@ -122,13 +124,50 @@ static struct xfs_db_btree *
> block_to_bt(
> struct xfs_btree_block *bb)
> {
> - struct xfs_db_btree *btp = &btrees[0];
> + struct xfs_db_btree *btp;
> + uint32_t magic;
> + bool crc;
> +
> + magic = be32_to_cpu((bb)->bb_magic);
> + for (btp = &btrees[0]; btp->magic != 0; btp++)
> + if (magic == btp->magic)
> + return btp;
{}
-Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
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