On Fri, 15 Jan 2010 14:30:10 -0500, "Theodore Ts'o" <tytso@xxxxxxx> wrote:
> Renaming the dio block allocation flags, variables, and functions
> introduced in Mingming's "Direct IO for holes and fallocate"
> patches so that they can be used by ext4 buffer write as well.
> Also changed the related function comments accordingly to cover
> both direct write and buffer wirte cases.
>
> Signed-off-by: Jiaying Zhang <jiayingz@xxxxxxxxxx>
> Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
> ---
> fs/ext4/ext4.h | 18 ++++++------
> fs/ext4/extents.c | 24 +++++++-------
> fs/ext4/fsync.c | 2 +-
> fs/ext4/inode.c | 84 ++++++++++++++++++++++++-----------------------------
> fs/ext4/super.c | 2 +-
> 5 files changed, 61 insertions(+), 69 deletions(-)
>
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 2ca1b41..b1dcbb7 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -133,7 +133,7 @@ struct mpage_da_data {
> int pages_written;
> int retval;
> };
> -#define DIO_AIO_UNWRITTEN 0x1
> +#define EXT4_IO_UNWRITTEN 0x1
> typedef struct ext4_io_end {
> struct list_head list; /* per-file finished AIO list */
> struct inode *inode; /* file being written to */
> @@ -364,13 +364,13 @@ struct ext4_new_group_data {
> /* caller is from the direct IO path, request to creation of an
> unitialized extents if not allocated, split the uninitialized
> extent if blocks has been preallocated already*/
> -#define EXT4_GET_BLOCKS_DIO 0x0008
> +#define EXT4_GET_BLOCKS_PRE_IO 0x0008
> #define EXT4_GET_BLOCKS_CONVERT 0x0010
> -#define EXT4_GET_BLOCKS_DIO_CREATE_EXT (EXT4_GET_BLOCKS_DIO|\
> +#define EXT4_GET_BLOCKS_IO_CREATE_EXT (EXT4_GET_BLOCKS_PRE_IO|\
> EXT4_GET_BLOCKS_CREATE_UNINIT_EXT)
> - /* Convert extent to initialized after direct IO complete */
> -#define EXT4_GET_BLOCKS_DIO_CONVERT_EXT (EXT4_GET_BLOCKS_CONVERT|\
> - EXT4_GET_BLOCKS_DIO_CREATE_EXT)
> + /* Convert extent to initialized after IO complete */
> +#define EXT4_GET_BLOCKS_IO_CONVERT_EXT (EXT4_GET_BLOCKS_CONVERT|\
> + EXT4_GET_BLOCKS_IO_CREATE_EXT)
>
All these flags are really confusing. I guess we can make it much more
cleaner. For ex: Why is EXT4_GET_BLOCKS_IO_CONVERT_EXT enabling
EXT4_GET_BLOCKS_CREATE_UNINIT_EXT. The renaming to PRE_IO made it
better. But i guess these names should be self documenting.
How about
EXT4_GET_BLOCKS_CREATE. Indicate we should do block
allocation. But that flag alone doesn't say whether we are suppose
to create init or uninit extent.
EXT4_GET_BLOCKS_UNINIT_EXT -> Request the creation of uninit extent
EXT4_GET_BLOCKS_CREATE_UNINIT_EXT -> EXT4_GET_BLOCKS_CREATE|EXT4_GET_BLOCKS_UNINIT_EXT;
EXT4_GET_BLOCKS_DELALLOC_RESERVE -> Request for delayed allocaion
reservation
EXT4_GET_BLOCKS_PRE_IO -> 0x0008 -> Indicate that we should do all
necessary extent split and make the requested range in to single extent.
EXT4_GET_BLOCKS_CONVERT_IO -> Convert the specified range which should be a
single extent into init and then try to merge the extent to left/right
EXT4_GET_BLOCKS_IO_CREATE_EXT -> EXT4_GET_BLOCKS_PRE_IO | EXT4_GET_BLOCKS_CREATE_UNINIT_EXT
EXT4_GET_BLOCKS_IO_CONVERT_EXT -> EXT4_GET_BLOCKS_CREATE | EXT4_GET_BLOCKS_CONVERT_IO;
So from the above list it is only the last flag that is different from
what is already there. But i guess we need more documentation around
these flags.
-aneesh
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