On Wed, May 09, 2018 at 09:48:07AM +0200, Christoph Hellwig wrote:
> This adds a simple iomap-based implementation of the legacy ->bmap
> interface. Note that we can't easily add checks for rt or reflink
> files, so these will have to remain in the callers. This interface
> just needs to die..
You /can/ check these...
if (iomap->bdev != inode->i_sb->s_bdev)
return 0;
if (iomap->flags & IOMAP_F_SHARED)
return 0;
> Signed-off-by: Christoph Hellwig <[email protected]>
> ---
> fs/iomap.c | 29 +++++++++++++++++++++++++++++
> include/linux/iomap.h | 3 +++
> 2 files changed, 32 insertions(+)
>
> diff --git a/fs/iomap.c b/fs/iomap.c
> index af525cb47339..049e0c4aacac 100644
> --- a/fs/iomap.c
> +++ b/fs/iomap.c
> @@ -1201,3 +1201,32 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> return ret;
> }
> EXPORT_SYMBOL_GPL(iomap_dio_rw);
> +
> +static loff_t
> +iomap_bmap_actor(struct inode *inode, loff_t pos, loff_t length,
> + void *data, struct iomap *iomap)
> +{
> + sector_t *bno = data;
> +
> + if (iomap->type == IOMAP_MAPPED)
> + *bno = (iomap->addr + pos - iomap->offset) >> inode->i_blkbits;
Does this need to be careful w.r.t. overflow on systems where sector_t
is a 32-bit unsigned long?
Also, ioctl_fibmap() typecasts the returned sector_t to an int, which
also seems broken. I agree the interface needs to die, but ioctls take
a long time to deprecate.
--D
> + return 0;
> +}
> +
> +/* legacy ->bmap interface. 0 is the error return (!) */
> +sector_t
> +iomap_bmap(struct address_space *mapping, sector_t bno,
> + const struct iomap_ops *ops)
> +{
> + struct inode *inode = mapping->host;
> + loff_t pos = bno >> inode->i_blkbits;
> + unsigned blocksize = i_blocksize(inode);
> +
> + if (filemap_write_and_wait(mapping))
> + return 0;
> +
> + bno = 0;
> + iomap_apply(inode, pos, blocksize, 0, ops, &bno, iomap_bmap_actor);
> + return bno;
> +}
> +EXPORT_SYMBOL_GPL(iomap_bmap);
> diff --git a/include/linux/iomap.h b/include/linux/iomap.h
> index 19a07de28212..07f73224c38b 100644
> --- a/include/linux/iomap.h
> +++ b/include/linux/iomap.h
> @@ -4,6 +4,7 @@
>
> #include <linux/types.h>
>
> +struct address_space;
> struct fiemap_extent_info;
> struct inode;
> struct iov_iter;
> @@ -95,6 +96,8 @@ loff_t iomap_seek_hole(struct inode *inode, loff_t offset,
> const struct iomap_ops *ops);
> loff_t iomap_seek_data(struct inode *inode, loff_t offset,
> const struct iomap_ops *ops);
> +sector_t iomap_bmap(struct address_space *mapping, sector_t bno,
> + const struct iomap_ops *ops);
>
> /*
> * Flags for direct I/O ->end_io:
> --
> 2.17.0
>
> --
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