[U-Boot] [PATCH 7/8] JFFS2: Use CLEANMARKER to reduce scanning time

[Heiko Schocher denx <hs@denx.de>]

Hello Mark,

Am 29.06.2015 um 07:02 schrieb Mark Tomlinson:
> If a sector has a CLEANMARKER at the beginning, it indicates that the
> entire sector has been erased. Therefore, if this is found, we can skip the
> entire block. This was not being done before this patch.
>
> The code now does the same as the kernel does when encountering a
> CLEANMARKER. It still checks that the next few words are FFFFFFFF, and if
> so, the block is assumed to be empty, and so is skipped.
>
> Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
> ---
>
>   fs/jffs2/jffs2_1pass.c | 22 ++++++++++++++++++++++
>   1 file changed, 22 insertions(+)

Beside of your comment style

Reviewed-by: Heiko Schocher <hs@denx.de>

bye,
Heiko
>
> diff --git a/fs/jffs2/jffs2_1pass.c b/fs/jffs2/jffs2_1pass.c
> index d78fb06..26a748f 100644
> --- a/fs/jffs2/jffs2_1pass.c
> +++ b/fs/jffs2/jffs2_1pass.c
> @@ -1520,6 +1520,8 @@ jffs2_1pass_build_lists(struct part_info * part)
>   		uint32_t sumlen;
>   		int ret;
>   #endif
> +		/* Indicates a sector with a CLEANMARKER was found */
> +		int clean_sector = 0;
>
>   		/* Set buf_size to maximum length */
>   		buf_size = DEFAULT_EMPTY_SCAN_SIZE;
> @@ -1643,6 +1645,13 @@ jffs2_1pass_build_lists(struct part_info * part)
>   					ofs += 4;
>   				}
>   				/* Ran off end. */
> +				/* If this sector had a clean marker at the
> +				 * beginning, and immediately following this
> +				 * have been a bunch of FF bytes, treat the
> +				 * entire sector as empty.
> +				 */
> +				if (clean_sector)
> +					break;
>
>   				/* See how much more there is to read in this
>   				 * eraseblock...
> @@ -1664,6 +1673,10 @@ jffs2_1pass_build_lists(struct part_info * part)
>   				buf_ofs = ofs;
>   				goto more_empty;
>   			}
> +			/* Found something not erased in the sector, so reset
> +			 * the 'clean_sector' flag.
> +			 */
> +			clean_sector = 0;
>   			if (node->magic != JFFS2_MAGIC_BITMASK ||
>   					!hdr_crc(node)) {
>   				ofs += 4;
> @@ -1745,6 +1758,15 @@ jffs2_1pass_build_lists(struct part_info * part)
>   						"%d != %zu\n",
>   						node->totlen,
>   						sizeof(struct jffs2_unknown_node));
> +				if ((node->totlen ==
> +				     sizeof(struct jffs2_unknown_node)) &&
> +				    (ofs == sector_ofs)) {
> +					/* Found a CLEANMARKER at the beginning
> +					 * of the sector. It's in the correct
> +					 * place with correct size and CRC.
> +					 */
> +					clean_sector = 1;
> +				}
>   				break;
>   			case JFFS2_NODETYPE_PADDING:
>   				if (node->totlen < sizeof(struct jffs2_unknown_node))
>

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