On Tue, Oct 15, 2024 at 06:13:50AM +0200, Christoph Hellwig wrote:
> iomap_want_unshare_iter currently sits in fs/iomap/buffered-io.c, which
> depends on CONFIG_BLOCK. It is also in used in fs/dax.c whіch has no
> such dependency. Given that it is a trivial check turn it into an inline
> in include/linux/iomap.h to fix the DAX && !BLOCK build.
>
> Fixes: 6ef6a0e821d3 ("iomap: share iomap_unshare_iter predicate code with fsdax")
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Heh, whoops. I forgot (a) that DAX && !BLOCK is a thing; and that
FS_DAX != DAX and was puzzling over this report yesterday.
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
--D
> ---
> fs/iomap/buffered-io.c | 17 -----------------
> include/linux/iomap.h | 19 +++++++++++++++++++
> 2 files changed, 19 insertions(+), 17 deletions(-)
>
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index 604f786be4bc54..ef0b68bccbb612 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -1270,23 +1270,6 @@ void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte,
> }
> EXPORT_SYMBOL_GPL(iomap_write_delalloc_release);
>
> -bool iomap_want_unshare_iter(const struct iomap_iter *iter)
> -{
> - /*
> - * Don't bother with blocks that are not shared to start with; or
> - * mappings that cannot be shared, such as inline data, delalloc
> - * reservations, holes or unwritten extents.
> - *
> - * Note that we use srcmap directly instead of iomap_iter_srcmap as
> - * unsharing requires providing a separate source map, and the presence
> - * of one is a good indicator that unsharing is needed, unlike
> - * IOMAP_F_SHARED which can be set for any data that goes into the COW
> - * fork for XFS.
> - */
> - return (iter->iomap.flags & IOMAP_F_SHARED) &&
> - iter->srcmap.type == IOMAP_MAPPED;
> -}
> -
> static loff_t iomap_unshare_iter(struct iomap_iter *iter)
> {
> struct iomap *iomap = &iter->iomap;
> diff --git a/include/linux/iomap.h b/include/linux/iomap.h
> index e04c060e8fe185..664c5f2f0aaa2d 100644
> --- a/include/linux/iomap.h
> +++ b/include/linux/iomap.h
> @@ -270,6 +270,25 @@ static inline loff_t iomap_last_written_block(struct inode *inode, loff_t pos,
> return round_up(pos + written, i_blocksize(inode));
> }
>
> +/*
> + * Check if the range needs to be unshared for a FALLOC_FL_UNSHARE_RANGE
> + * operation.
> + *
> + * Don't bother with blocks that are not shared to start with; or mappings that
> + * cannot be shared, such as inline data, delalloc reservations, holes or
> + * unwritten extents.
> + *
> + * Note that we use srcmap directly instead of iomap_iter_srcmap as unsharing
> + * requires providing a separate source map, and the presence of one is a good
> + * indicator that unsharing is needed, unlike IOMAP_F_SHARED which can be set
> + * for any data that goes into the COW fork for XFS.
> + */
> +static inline bool iomap_want_unshare_iter(const struct iomap_iter *iter)
> +{
> + return (iter->iomap.flags & IOMAP_F_SHARED) &&
> + iter->srcmap.type == IOMAP_MAPPED;
> +}
> +
> ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
> const struct iomap_ops *ops, void *private);
> int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops);
> --
> 2.45.2
>
>
