Re: [PATCH v11 16/21] vfs,ext2: Remove CONFIG_EXT2_FS_XIP and rename CONFIG_FS_XIP to CONFIG_FS_DAX

[Mathieu Desnoyers <mathieu.desnoyers@efficios.com>]

On 25-Sep-2014 04:33:33 PM, Matthew Wilcox wrote:
> The fewer Kconfig options we have the better.  Use the generic
> CONFIG_FS_DAX to enable XIP support in ext2 as well as in the core.
> 
> Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
> ---
>  fs/Kconfig         | 21 ++++++++++++++-------
>  fs/Makefile        |  2 +-
>  fs/ext2/Kconfig    | 11 -----------
>  fs/ext2/ext2.h     |  2 +-
>  fs/ext2/file.c     |  4 ++--
>  fs/ext2/super.c    |  4 ++--
>  include/linux/fs.h |  4 ++--
>  7 files changed, 22 insertions(+), 26 deletions(-)
> 
> diff --git a/fs/Kconfig b/fs/Kconfig
> index 312393f..a9eb53d 100644
> --- a/fs/Kconfig
> +++ b/fs/Kconfig
> @@ -13,13 +13,6 @@ if BLOCK
>  source "fs/ext2/Kconfig"
>  source "fs/ext3/Kconfig"
>  source "fs/ext4/Kconfig"
> -
> -config FS_XIP
> -# execute in place
> -	bool
> -	depends on EXT2_FS_XIP
> -	default y
> -
>  source "fs/jbd/Kconfig"
>  source "fs/jbd2/Kconfig"
>  
> @@ -40,6 +33,20 @@ source "fs/ocfs2/Kconfig"
>  source "fs/btrfs/Kconfig"
>  source "fs/nilfs2/Kconfig"
>  
> +config FS_DAX
> +	bool "Direct Access support"
> +	depends on MMU
> +	help
> +	  Direct Access (DAX) can be used on memory-backed block devices.
> +	  If the block device supports DAX and the filesystem supports DAX,
> +	  then you can avoid using the pagecache to buffer I/Os.  Turning
> +	  on this option will compile in support for DAX; you will need to
> +	  mount the filesystem using the -o xip option.

There is a mismatch between the documentation file (earlier patch): -o
dax, and this config description: -o xip.

I guess we might want to switch the mount option to "-o dax" and
document it as such, and since it should be usable transparently for the
same use-cases "-o xip" was enabling, we might want to keep parsing of
"-o xip" in the code for backward compatibility.

Thoughts ?

Thanks,

Mathieu

> +
> +	  If you do not have a block device that is capable of using this,
> +	  or if unsure, say N.  Saying Y will increase the size of the kernel
> +	  by about 2kB.
> +
>  endif # BLOCK
>  
>  # Posix ACL utility routines
> diff --git a/fs/Makefile b/fs/Makefile
> index 0325ec3..df4a4cf 100644
> --- a/fs/Makefile
> +++ b/fs/Makefile
> @@ -28,7 +28,7 @@ obj-$(CONFIG_SIGNALFD)		+= signalfd.o
>  obj-$(CONFIG_TIMERFD)		+= timerfd.o
>  obj-$(CONFIG_EVENTFD)		+= eventfd.o
>  obj-$(CONFIG_AIO)               += aio.o
> -obj-$(CONFIG_FS_XIP)		+= dax.o
> +obj-$(CONFIG_FS_DAX)		+= dax.o
>  obj-$(CONFIG_FILE_LOCKING)      += locks.o
>  obj-$(CONFIG_COMPAT)		+= compat.o compat_ioctl.o
>  obj-$(CONFIG_BINFMT_AOUT)	+= binfmt_aout.o
> diff --git a/fs/ext2/Kconfig b/fs/ext2/Kconfig
> index 14a6780..c634874e 100644
> --- a/fs/ext2/Kconfig
> +++ b/fs/ext2/Kconfig
> @@ -42,14 +42,3 @@ config EXT2_FS_SECURITY
>  
>  	  If you are not using a security module that requires using
>  	  extended attributes for file security labels, say N.
> -
> -config EXT2_FS_XIP
> -	bool "Ext2 execute in place support"
> -	depends on EXT2_FS && MMU
> -	help
> -	  Execute in place can be used on memory-backed block devices. If you
> -	  enable this option, you can select to mount block devices which are
> -	  capable of this feature without using the page cache.
> -
> -	  If you do not use a block device that is capable of using this,
> -	  or if unsure, say N.
> diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
> index 5ecf570..b30c3bd 100644
> --- a/fs/ext2/ext2.h
> +++ b/fs/ext2/ext2.h
> @@ -380,7 +380,7 @@ struct ext2_inode {
>  #define EXT2_MOUNT_NO_UID32		0x000200  /* Disable 32-bit UIDs */
>  #define EXT2_MOUNT_XATTR_USER		0x004000  /* Extended user attributes */
>  #define EXT2_MOUNT_POSIX_ACL		0x008000  /* POSIX Access Control Lists */
> -#ifdef CONFIG_FS_XIP
> +#ifdef CONFIG_FS_DAX
>  #define EXT2_MOUNT_XIP			0x010000  /* Execute in place */
>  #else
>  #define EXT2_MOUNT_XIP			0
> diff --git a/fs/ext2/file.c b/fs/ext2/file.c
> index da8dc64..46b333d 100644
> --- a/fs/ext2/file.c
> +++ b/fs/ext2/file.c
> @@ -25,7 +25,7 @@
>  #include "xattr.h"
>  #include "acl.h"
>  
> -#ifdef CONFIG_EXT2_FS_XIP
> +#ifdef CONFIG_FS_DAX
>  static int ext2_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
>  {
>  	return dax_fault(vma, vmf, ext2_get_block);
> @@ -109,7 +109,7 @@ const struct file_operations ext2_file_operations = {
>  	.splice_write	= iter_file_splice_write,
>  };
>  
> -#ifdef CONFIG_EXT2_FS_XIP
> +#ifdef CONFIG_FS_DAX
>  const struct file_operations ext2_xip_file_operations = {
>  	.llseek		= generic_file_llseek,
>  	.read		= new_sync_read,
> diff --git a/fs/ext2/super.c b/fs/ext2/super.c
> index 0393c6d..feb53d8 100644
> --- a/fs/ext2/super.c
> +++ b/fs/ext2/super.c
> @@ -287,7 +287,7 @@ static int ext2_show_options(struct seq_file *seq, struct dentry *root)
>  		seq_puts(seq, ",grpquota");
>  #endif
>  
> -#if defined(CONFIG_EXT2_FS_XIP)
> +#ifdef CONFIG_FS_DAX
>  	if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
>  		seq_puts(seq, ",xip");
>  #endif
> @@ -549,7 +549,7 @@ static int parse_options(char *options, struct super_block *sb)
>  			break;
>  #endif
>  		case Opt_xip:
> -#ifdef CONFIG_EXT2_FS_XIP
> +#ifdef CONFIG_FS_DAX
>  			set_opt (sbi->s_mount_opt, XIP);
>  #else
>  			ext2_msg(sb, KERN_INFO, "xip option not supported");
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index d73db11..e6b48cc 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1642,7 +1642,7 @@ struct super_operations {
>  #define IS_IMA(inode)		((inode)->i_flags & S_IMA)
>  #define IS_AUTOMOUNT(inode)	((inode)->i_flags & S_AUTOMOUNT)
>  #define IS_NOSEC(inode)		((inode)->i_flags & S_NOSEC)
> -#ifdef CONFIG_FS_XIP
> +#ifdef CONFIG_FS_DAX
>  #define IS_DAX(inode)		((inode)->i_flags & S_DAX)
>  #else
>  #define IS_DAX(inode)		0
> @@ -2488,7 +2488,7 @@ extern loff_t fixed_size_llseek(struct file *file, loff_t offset,
>  extern int generic_file_open(struct inode * inode, struct file * filp);
>  extern int nonseekable_open(struct inode * inode, struct file * filp);
>  
> -#ifdef CONFIG_FS_XIP
> +#ifdef CONFIG_FS_DAX
>  int dax_clear_blocks(struct inode *, sector_t block, long size);
>  int dax_truncate_page(struct inode *, loff_t from, get_block_t);
>  ssize_t dax_do_io(int rw, struct kiocb *, struct inode *, struct iov_iter *,
> -- 
> 2.1.0
> 
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org.  For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
> 
> 

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
Key fingerprint: 2A0B 4ED9 15F2 D3FA 45F5  B162 1728 0A97 8118 6ACF

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>