[Cluster-devel] [gfs2-utils PATCH] gfs2_edit: Make 'j' jump to journaled block on log descriptors

[Andrew Price <anprice@redhat.com>]

On 25/05/16 19:03, Bob Peterson wrote:
> Hi,
>
> This is a bit of a quick hack, but it works:
>
> The jump command ordinarily jumps to the absolute block in the file
> system. That makes sense for almost all cases. For log descriptors,
> you're usually more interested in the journaled blocks than the
> actual blocks. So this patch makes 'j' jump to the journaled version
> of the block rather than the absolute block, when you're looking
> at a log descriptor block.
>
> Signed-off-by: Bob Peterson <rpeterso@redhat.com>

ACK

Andy

> ---
> diff --git a/gfs2/edit/hexedit.c b/gfs2/edit/hexedit.c
> index 2ce111d..40a719e 100644
> --- a/gfs2/edit/hexedit.c
> +++ b/gfs2/edit/hexedit.c
> @@ -545,6 +545,17 @@ static const struct lgfs2_metadata *find_mtype(uint32_t mtype, const unsigned ve
>  	return NULL;
>  }
>
> +static int get_pnum(int ptroffset)
> +{
> +	int pnum;
> +
> +	pnum = pgnum * screen_chunk_size;
> +	pnum += (ptroffset - struct_len);
> +	pnum /= sizeof(uint64_t);
> +
> +	return pnum;
> +}
> +
>  /* ------------------------------------------------------------------------ */
>  /* hexdump - hex dump the filesystem block to the screen                    */
>  /* ------------------------------------------------------------------------ */
> @@ -559,6 +570,7 @@ static int hexdump(uint64_t startaddr, int len, int trunc_zeros,
>  	int print_field, cursor_line;
>  	const uint32_t block_type = get_block_type(bh, NULL);
>  	uint64_t *ref;
> +	int ptroffset = 0;
>
>  	strcpy(edit_fmt,"%02x");
>  	pointer = (unsigned char *)lpBuffer + offset;
> @@ -679,19 +691,17 @@ static int hexdump(uint64_t startaddr, int len, int trunc_zeros,
>  		}
>  		if (cursor_line) {
>  			if (block_type == GFS2_METATYPE_IN ||
> +			    block_type == GFS2_METATYPE_LD ||
>  			    ((block_type == GFS2_METATYPE_DI) &&
>  			     ((struct gfs2_dinode*)bh->b_data)->di_height) ||
>  			     S_ISDIR(di.di_mode)) {
> -				int ptroffset = edit_row[dmode] * 16 +
> +				ptroffset = edit_row[dmode] * 16 +
>  					edit_col[dmode];
>
>  				if (ptroffset >= struct_len || pgnum) {
> -					int pnum;
> -
> -					pnum = pgnum * screen_chunk_size;
> -					pnum += (ptroffset - struct_len);
> -					pnum /= sizeof(uint64_t);
> -
> +					int pnum = get_pnum(ptroffset);
> +					if (block_type == GFS2_METATYPE_LD)
> +						print_gfs2("*");
>  					print_gfs2("pointer 0x%x", pnum);
>  				}
>  			}
> @@ -713,6 +723,13 @@ static int hexdump(uint64_t startaddr, int len, int trunc_zeros,
>  		if ((const char *)pointer >= zeros_strt)
>  			break;
>  	} /* while */
> +	if (block_type == GFS2_METATYPE_LD && ptroffset >= struct_len) {
> +		COLORS_NORMAL;
> +		eol(0);
> +		print_gfs2("         * 'j' will jump to the journaled block, "
> +			   "not the absolute block.");
> +		eol(0);
> +	}
>  	if (sbd.gfs1) {
>  		COLORS_NORMAL;
>  		print_gfs2("         *** This seems to be a GFS-1 file system ***");
> @@ -1610,18 +1627,28 @@ static void pagedn(void)
>
>  /* ------------------------------------------------------------------------ */
>  /* jump - jump to the address the cursor is on                              */
> +/*                                                                          */
> +/* If the cursor is in a log descriptor, jump to the log-descriptor version */
> +/* of the block instead of the "real" block.                                */
>  /* ------------------------------------------------------------------------ */
>  static void jump(void)
>  {
>  	if (dmode == HEX_MODE) {
>  		unsigned int col2;
>  		uint64_t *b;
> +		const uint32_t block_type = get_block_type(bh, NULL);
>  		
> -		if (edit_row[dmode] >= 0) {
> +		/* special exception for log descriptors: jump the journaled
> +		   version of the block, not the "real" block */
> +		if (block_type == GFS2_METATYPE_LD) {
> +			int ptroffset = edit_row[dmode] * 16 + edit_col[dmode];
> +			int pnum = get_pnum(ptroffset);
> +			temp_blk = bh->b_blocknr + pnum + 1;
> +		} else if (edit_row[dmode] >= 0) {
>  			col2 = edit_col[dmode] & 0x08;/* thus 0-7->0, 8-15->8 */
>  			b = (uint64_t *)&bh->b_data[edit_row[dmode]*16 +
>  						    offset + col2];
> -			temp_blk=be64_to_cpu(*b);
> +			temp_blk = be64_to_cpu(*b);
>  		}
>  	}
>  	else
>