[Cluster-devel] [fsck.gfs2 patch] fsck.gfs2: remove duplicate designation during undo

[Andrew Price <anprice@redhat.com>]

Hi,

Looks good to me, ACK to all 5 patches.

Andy

On 09/01/15 19:34, Bob Peterson wrote:
> Hi,
>
> This patch fixes a problem whereby fsck.gfs2's pass1 would perform this
> sequence of events:
> 1. Metadata block X is identified as being referenced from dinode D1.
> 2. Metadata block X is identified as being referenced from another dinode, D2,
>     which makes it a duplicate reference, but so far, no serious errors were
>     found for that dinode.
> 3. Dinode D2 is found later to be irreparably damaged, and needs to be removed.
> When D2 is deleted, the duplicate reference from D2 is removed and block X is
> not freed because D1 still references it. However, it's still marked as a
> duplicate and requires processing in pass1b.
>
> Later, pass1b resolves the duplicate and determine's there is really only one
> reference remaining, so it makes the correct decision. However, it should not
> be necessary. The "undo" functions should remove the duplicate reference if
> (and only if) the only reference was from D2. Note, though, that if the
> corruption is found later in the cycle (after "undo" is possible) the duplicate
> reference MUST remain and be resolved by pass1b.
>
> Regards,
>
> Bob Peterson
> Red Hat File Systems
>
> Signed-off-by: Bob Peterson <rpeterso@redhat.com>
> ---
> diff --git a/gfs2/fsck/pass1.c b/gfs2/fsck/pass1.c
> index a4ba04c..73b054c 100644
> --- a/gfs2/fsck/pass1.c
> +++ b/gfs2/fsck/pass1.c
> @@ -364,6 +364,11 @@ static int undo_reference(struct gfs2_inode *ip, uint64_t block, int meta,
>   				  "from another inode; not freeing.\n"),
>   				(unsigned long long)block,
>   				(unsigned long long)block);
> +			if (dt->refs == 1) {
> +				log_err(_("This was the only duplicate "
> +					  "reference so far; removing it.\n"));
> +				dup_delete(dt);
> +			}
>   			return 1;
>   		}
>   	}
> @@ -1055,8 +1060,13 @@ static int rangecheck_block(struct gfs2_inode *ip, uint64_t block,
>   			  (unsigned long long)ip->i_di.di_num.no_addr);
>   		if ((*bad_pointers) <= BAD_POINTER_TOLERANCE)
>   			return meta_is_good;
> -		else
> +		else {
> +			log_debug(_("Inode 0x%llx bad pointer tolerance "
> +				    "exceeded: block 0x%llx.\n"),
> +				  (unsigned long long)ip->i_di.di_num.no_addr,
> +				  (unsigned long long)block);
>   			return meta_error; /* Exits check_metatree quicker */
> +		}
>   	}
>   	return meta_is_good;
>   }
>