Re: [PATCH 1/3] statxat: Provide IOC flags for Windows fs attributes

[Andreas Dilger <adilger at dilger dot ca>]

On Nov 12, 2013, at 10:35 AM, David Howells <dhowells@redhat.com> wrote:
> Provide IOC flags for Windows fs attributes so that they can be retrieved (or
> even altered) using the FS_IOC_[GS]ETFLAGS ioctl and read using statxat().
> 
> Signed-off-by: David Howells <dhowells@redhat.com>
> ---
> 
> include/uapi/linux/fs.h |    7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
> index 6c28b61bb690..8b966f48dd41 100644
> --- a/include/uapi/linux/fs.h
> +++ b/include/uapi/linux/fs.h
> @@ -191,10 +191,13 @@ struct inodes_stat_t {
> #define FS_EXTENT_FL			0x00080000 /* Extents */
> #define FS_DIRECTIO_FL			0x00100000 /* Use direct i/o */
> #define FS_NOCOW_FL			0x00800000 /* Do not cow file */
> +#define FS_HIDDEN_FL			0x10000000 /* Windows hidden file attribute */

The 0x10000000 flag is used by ext4 as EXT4_INLINE_DATA_FL.  This would basically fill
up all of the inode flags for ext2/3/4, and while there isn’t a guarantee that there
will not be any conflicts between FS_*_FL and EXT4_*_FL, it is a lot easier if they
are the same.

One option is to move FS_HIDDEN_FL over to use 0x04000000, which is currently used as
EXT4_SNAPFILE_DELETED_FL, but that is IMHO an ext4-internal flag that it isn’t in
common use anywhere, and isn’t so bad to have a conflict with.

Ted, any thoughts on this?

Cheers, Andreas

> +#define FS_SYSTEM_FL			0x20000000 /* Windows system file attribute */
> +#define FS_ARCHIVE_FL			0x40000000 /* Windows archive file attribute */
> #define FS_RESERVED_FL			0x80000000 /* reserved for ext2 lib */
> 
> -#define FS_FL_USER_VISIBLE		0x0003DFFF /* User visible flags */
> -#define FS_FL_USER_MODIFIABLE		0x000380FF /* User modifiable flags */
> +#define FS_FL_USER_VISIBLE		0x7003DFFF /* User visible flags */
> +#define FS_FL_USER_MODIFIABLE		0x700380FF /* User modifiable flags */
> 
> 
> #define SYNC_FILE_RANGE_WAIT_BEFORE	1
> 
> --
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Cheers, Andreas

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