On Sun, Aug 21, 2016 at 11:47:03PM +0200, Christoph Hellwig wrote:
> Filesystems like XFS that use extents should not set the
> FIEMAP_EXTENT_MERGED flag in the fiemap extent structures. To allow
> for both behaviors for the upcoming gfs2 usage split the iomap
> type field into type and flags, and only set FIEMAP_EXTENT_MERGED if
> the IOMAP_F_MERGED flag is set. The flags field will also come in
> handy for future features such as shared extents on reflink-enabled
> file systems.
You can add an:
Acked-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
I'm going to send in a similar patch adding a SHARED flag when I
send out the XFS reflink series for review later this week.
--D
>
> Reported-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> fs/iomap.c | 5 ++++-
> include/linux/iomap.h | 8 +++++++-
> 2 files changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/fs/iomap.c b/fs/iomap.c
> index 0342254..706270f 100644
> --- a/fs/iomap.c
> +++ b/fs/iomap.c
> @@ -428,9 +428,12 @@ static int iomap_to_fiemap(struct fiemap_extent_info *fi,
> break;
> }
>
> + if (iomap->flags & IOMAP_F_MERGED)
> + flags |= FIEMAP_EXTENT_MERGED;
> +
> return fiemap_fill_next_extent(fi, iomap->offset,
> iomap->blkno != IOMAP_NULL_BLOCK ? iomap->blkno << 9: 0,
> - iomap->length, flags | FIEMAP_EXTENT_MERGED);
> + iomap->length, flags);
>
> }
>
> diff --git a/include/linux/iomap.h b/include/linux/iomap.h
> index 3267df4..3d70ece 100644
> --- a/include/linux/iomap.h
> +++ b/include/linux/iomap.h
> @@ -19,6 +19,11 @@ struct vm_fault;
> #define IOMAP_UNWRITTEN 0x04 /* blocks allocated @blkno in unwritten
> state */
>
> /*
> + * Flags for iomap mappings:
> + */
> +#define IOMAP_F_MERGED 0x01 /* contains multiple blocks/extents */
> +
> +/*
> * Magic value for blkno:
> */
> #define IOMAP_NULL_BLOCK -1LL /* blkno is not valid */
> @@ -27,7 +32,8 @@ struct iomap {
> sector_t blkno; /* 1st sector of mapping, 512b units */
> loff_t offset; /* file offset of mapping, bytes */
> u64 length; /* length of mapping, bytes */
> - int type; /* type of mapping */
> + u16 type; /* type of mapping */
> + u16 flags; /* flags for mapping */
> struct block_device *bdev; /* block device for I/O */
> };
>
> --
> 2.1.4
>
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