Re: [PATCH 10/10] Add yaffs2 file system: Hook in to Linux tree

[Jesper Juhl]

Hi Charles,

A few minor comments below.


On Fri, 14 Jan 2011, Charles Manning wrote:

> Change existing Makefile, Kconfig and MAINTAINERS.
> Add yaffs2 specific Makefile and Kconfig
> 
> Signed-off-by: Charles Manning <cdhmanning@xxxxxxxxx>
> ---
>  MAINTAINERS        |    7 ++
>  fs/Kconfig         |    1 +
>  fs/Makefile        |    1 +
>  fs/yaffs2/Kconfig  |  161 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  fs/yaffs2/Makefile |   17 ++++++
>  5 files changed, 187 insertions(+), 0 deletions(-)
>  create mode 100644 fs/yaffs2/Kconfig
>  create mode 100644 fs/yaffs2/Makefile
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 64d7621..4cc7215 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -6838,6 +6838,13 @@ L:	linux-serial@xxxxxxxxxxxxxxx
>  S:	Maintained
>  F:	drivers/serial/uartlite.c
>  
> +YAFFS2 FLASH FILE SYSTEM
> +M:	Charles Manning <cdhmanning@xxxxxxxxx>
> +W:	http://www.yaffs.net/
> +L:	yaffs@xxxxxxxxxxxxxxxxxx
> +S:	Maintained
> +F:	fs/yaffs2
> +
>  YAM DRIVER FOR AX.25
>  M:	Jean-Paul Roubelat <jpr@xxxxxxxxx>
>  L:	linux-hams@xxxxxxxxxxxxxxx
> diff --git a/fs/Kconfig b/fs/Kconfig
> index 771f457..069abb1 100644
> --- a/fs/Kconfig
> +++ b/fs/Kconfig
> @@ -176,6 +176,7 @@ source "fs/hfsplus/Kconfig"
>  source "fs/befs/Kconfig"
>  source "fs/bfs/Kconfig"
>  source "fs/efs/Kconfig"
> +source "fs/yaffs2/Kconfig"
>  source "fs/jffs2/Kconfig"
>  # UBIFS File system configuration
>  source "fs/ubifs/Kconfig"
> diff --git a/fs/Makefile b/fs/Makefile
> index a7f7cef..e370ea5 100644
> --- a/fs/Makefile
> +++ b/fs/Makefile
> @@ -121,3 +121,4 @@ obj-$(CONFIG_BTRFS_FS)		+= btrfs/
>  obj-$(CONFIG_GFS2_FS)           += gfs2/
>  obj-$(CONFIG_EXOFS_FS)          += exofs/
>  obj-$(CONFIG_CEPH_FS)		+= ceph/
> +obj-$(CONFIG_YAFFS_FS)		+= yaffs2/
> diff --git a/fs/yaffs2/Kconfig b/fs/yaffs2/Kconfig
> new file mode 100644
> index 0000000..6354140
> --- /dev/null
> +++ b/fs/yaffs2/Kconfig
> @@ -0,0 +1,161 @@
> +#
> +# YAFFS file system configurations
> +#
> +
> +config YAFFS_FS
> +	tristate "YAFFS2 file system support"

"file system"

> +	default n
> +	depends on MTD_BLOCK
> +	select YAFFS_YAFFS1
> +	select YAFFS_YAFFS2
> +	help
> +	  YAFFS2, or Yet Another Flash Filing System, is a filing system

"filing system"

> +	  optimised for NAND Flash chips.
> +
> +	  To compile the YAFFS2 file system support as a module, choose M

"file system"

Why "file system" in some places and "filing system" in others?


> +	  here: the module will be called yaffs2.
> +
> +	  If unsure, say N.
> +
> +	  Further information on YAFFS2 is available at
> +	  <http://www.aleph1.co.uk/yaffs/>.
> +
> +config YAFFS_YAFFS1
> +	bool "512 byte / page devices"
> +	depends on YAFFS_FS
> +	default y
> +	help
> +	  Enable YAFFS1 support -- yaffs for 512 byte / page devices
> +
> +	  Not needed for 2K-page devices.
> +
> +	  If unsure, say Y.
> +
> +config YAFFS_9BYTE_TAGS
> +	bool "Use older-style on-NAND data format with pageStatus byte"
> +	depends on YAFFS_YAFFS1
> +	default n
> +	help
> +
> +	  Older-style on-NAND data format has a "pageStatus" byte to record
> +	  chunk/page state.  This byte is zero when the page is discarded.
> +	  Choose this option if you have existing on-NAND data using this
> +	  format that you need to continue to support.  New data written
> +	  also uses the older-style format.  Note: Use of this option
> +	  generally requires that MTD's oob layout be adjusted to use the
> +	  older-style format.  See notes on tags formats and MTD versions
> +	  in yaffs_mtdif1.c.
> +
> +	  If unsure, say N.
> +
> +config YAFFS_DOES_ECC
> +	bool "Lets Yaffs do its own ECC"

Shouldn't this read "Let Yaffs do its own ECC" ?
Ohh and why the different capitalization? Here it is "Yaffs", elsewhere it 
it is "YAFFS".


> +	depends on YAFFS_FS && YAFFS_YAFFS1 && !YAFFS_9BYTE_TAGS
> +	default n
> +	help
> +	  This enables Yaffs to use its own ECC functions instead of using

Again - "Yaffs" vs "YAFFS". Personally I'd say "pick one".


> +	  the ones from the generic MTD-NAND driver.
> +
> +	  If unsure, say N.
> +
> +config YAFFS_ECC_WRONG_ORDER
> +	bool "Use the same ecc byte order as Steven Hill's nand_ecc.c"

Shouldn't this be "Use the same ECC byte order ..." ?


> +	depends on YAFFS_FS && YAFFS_DOES_ECC && !YAFFS_9BYTE_TAGS
> +	default n
> +	help
> +	  This makes yaffs_ecc.c use the same ecc byte order as Steven
> +	  Hill's nand_ecc.c. If not set, then you get the same ecc byte

ECC?


> +	  order as SmartMedia.
> +
> +	  If unsure, say N.
> +
> +config YAFFS_YAFFS2
> +	bool "2048 byte (or larger) / page devices"
> +	depends on YAFFS_FS
> +	default y
> +	help
> +	  Enable YAFFS2 support -- yaffs for >= 2K bytes per page devices

YAFFS vs Yaffs vs yaffs... - elsewhere as well, not pointing this out for 
the rest of the patch..


> +
> +	  If unsure, say Y.
> +
> +config YAFFS_AUTO_YAFFS2
> +	bool "Autoselect yaffs2 format"
> +	depends on YAFFS_YAFFS2
> +	default y
> +	help
> +	  Without this, you need to explicitely use yaffs2 as the file
> +	  system type. With this, you can say "yaffs" and yaffs or yaffs2
> +	  will be used depending on the device page size (yaffs on
> +	  512-byte page devices, yaffs2 on 2K page devices).
> +
> +	  If unsure, say Y.
> +
> +config YAFFS_DISABLE_TAGS_ECC
> +	bool "Disable YAFFS from doing ECC on tags by default"
> +	depends on YAFFS_FS && YAFFS_YAFFS2
> +	default n
> +	help
> +	  This defaults Yaffs to using its own ECC calculations on tags instead of
> +	  just relying on the MTD.
> +	  This behavior can also be overridden with tags_ecc_on and
> +	  tags_ecc_off mount options.
> +
> +	  If unsure, say N.
> +
> +config YAFFS_ALWAYS_CHECK_CHUNK_ERASED
> +	bool "Force chunk erase check"
> +	depends on YAFFS_FS
> +	default n
> +	help
> +          Normally YAFFS only checks chunks before writing until an erased

You don't have this extra indentation at the start of the first line for 
other help entries...


> +	  chunk is found. This helps to detect any partially written
> +	  chunks that might have happened due to power loss.
> +
> +	  Enabling this forces on the test that chunks are erased in flash
> +	  before writing to them. This takes more time but is potentially
> +	  a bit more secure.
> +
> +	  Suggest setting Y during development and ironing out driver

Perhaps "It is suggested to set this to Y during development ..." or "We 
recommend setting this to Y during .." - the current wording is a little 
clumsy IMHO.

> +	  issues etc. Suggest setting to N if you want faster writing.
> +

Same for "N".


> +	  If unsure, say Y.
> +
> +config YAFFS_EMPTY_LOST_AND_FOUND
> +	bool "Empty lost and found on boot"
> +	depends on YAFFS_FS
> +	default n
> +	help
> +	  If this is enabled then the contents of lost and found is
> +	  automatically dumped at mount.

Hmm, isn't the dir named "lost+found", not "lost and found" ?


> +
> +	  If unsure, say N.
> +
> +config YAFFS_DISABLE_BLOCK_REFRESHING
> +	bool "Disable yaffs2 block refreshing"
> +	depends on YAFFS_FS
> +	default n
> +	help
> +	 If this is set, then block refreshing is disabled.
> +	 Block refreshing infrequently refreshes the oldest block in
> +	 a yaffs2 file system. This mechanism helps to refresh flash to
> +	 mitigate against data loss. This is particularly useful for MLC.
> +
> +	  If unsure, say N.
> +
> +config YAFFS_DISABLE_BACKGROUND
> +	bool "Disable yaffs2 background processing"
> +	depends on YAFFS_FS
> +	default n
> +	help
> +	 If this is set, then background processing is disabled.
> +	 Background processing makes many foreground activities faster.
> +
> +	 If unsure, say N.
> +
> +config YAFFS_XATTR
> +	bool "Enable yaffs2 xattr support"
> +	depends on YAFFS_FS
> +	default y
> +	help
> +	 If this is set then yaffs2 will provide xattr support.
> +	 If unsure, say Y.

You usually have a blank line before the "If unsure, say X" line, but not 
here - I think you should have.


> diff --git a/fs/yaffs2/Makefile b/fs/yaffs2/Makefile
> new file mode 100644
> index 0000000..e63a28a
> --- /dev/null
> +++ b/fs/yaffs2/Makefile
> @@ -0,0 +1,17 @@
> +#
> +# Makefile for the linux YAFFS filesystem routines.
> +#
> +
> +obj-$(CONFIG_YAFFS_FS) += yaffs.o
> +
> +yaffs-y := yaffs_ecc.o yaffs_vfs.o yaffs_guts.o yaffs_checkptrw.o
> +yaffs-y += yaffs_packedtags1.o yaffs_packedtags2.o yaffs_nand.o
> +yaffs-y += yaffs_tagscompat.o yaffs_tagsvalidity.o
> +yaffs-y += yaffs_mtdif.o yaffs_mtdif1.o yaffs_mtdif2.o
> +yaffs-y += yaffs_nameval.o yaffs_attribs.o
> +yaffs-y += yaffs_allocator.o
> +yaffs-y += yaffs_yaffs1.o
> +yaffs-y += yaffs_yaffs2.o
> +yaffs-y += yaffs_bitmap.o
> +yaffs-y += yaffs_verify.o
> +
> 

-- 
Jesper Juhl <jj@xxxxxxxxxxxxx>            http://www.chaosbits.net/
Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html
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