Re: [PATCH 26/29] fsdax: shift partition offset handling into the file systems

["Darrick J. Wong" <djwong@kernel.org>]

On Mon, Nov 29, 2021 at 11:22:00AM +0100, Christoph Hellwig wrote:
> Remove the last user of ->bdev in dax.c by requiring the file system to
> pass in an address that already includes the DAX offset.  As part of the
> only set ->bdev or ->daxdev when actually required in the ->iomap_begin
> methods.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> [erofs]

Looks like a straightfoward conversion.  In addition to reviewing the
xfs parts, I spot-checked the ext* bits and didn't see anything
obviously wrong there, but you might want to get an ack from Ted and
Jan.

Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
>  fs/dax.c            |  6 +-----
>  fs/erofs/data.c     | 11 +++++++++--
>  fs/erofs/internal.h |  1 +
>  fs/ext2/inode.c     |  8 ++++++--
>  fs/ext4/inode.c     | 16 +++++++++++-----
>  fs/xfs/xfs_iomap.c  | 10 ++++++++--
>  6 files changed, 36 insertions(+), 16 deletions(-)
> 
> diff --git a/fs/dax.c b/fs/dax.c
> index 148e8b0967f35..e0eecd8e3a8f8 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -711,11 +711,7 @@ int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
>  
>  static pgoff_t dax_iomap_pgoff(const struct iomap *iomap, loff_t pos)
>  {
> -	phys_addr_t paddr = iomap->addr + (pos & PAGE_MASK) - iomap->offset;
> -
> -	if (iomap->bdev)
> -		paddr += (get_start_sect(iomap->bdev) << SECTOR_SHIFT);
> -	return PHYS_PFN(paddr);
> +	return PHYS_PFN(iomap->addr + (pos & PAGE_MASK) - iomap->offset);
>  }
>  
>  static int copy_cow_page_dax(struct vm_fault *vmf, const struct iomap_iter *iter)
> diff --git a/fs/erofs/data.c b/fs/erofs/data.c
> index 0e35ef3f9f3d7..9b1bb177ce303 100644
> --- a/fs/erofs/data.c
> +++ b/fs/erofs/data.c
> @@ -159,6 +159,7 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
>  	/* primary device by default */
>  	map->m_bdev = sb->s_bdev;
>  	map->m_daxdev = EROFS_SB(sb)->dax_dev;
> +	map->m_dax_part_off = EROFS_SB(sb)->dax_part_off;
>  
>  	if (map->m_deviceid) {
>  		down_read(&devs->rwsem);
> @@ -169,6 +170,7 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
>  		}
>  		map->m_bdev = dif->bdev;
>  		map->m_daxdev = dif->dax_dev;
> +		map->m_dax_part_off = dif->dax_part_off;
>  		up_read(&devs->rwsem);
>  	} else if (devs->extra_devices) {
>  		down_read(&devs->rwsem);
> @@ -185,6 +187,7 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
>  				map->m_pa -= startoff;
>  				map->m_bdev = dif->bdev;
>  				map->m_daxdev = dif->dax_dev;
> +				map->m_dax_part_off = dif->dax_part_off;
>  				break;
>  			}
>  		}
> @@ -215,9 +218,13 @@ static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
>  	if (ret)
>  		return ret;
>  
> -	iomap->bdev = mdev.m_bdev;
> -	iomap->dax_dev = mdev.m_daxdev;
>  	iomap->offset = map.m_la;
> +	if (flags & IOMAP_DAX) {
> +		iomap->dax_dev = mdev.m_daxdev;
> +		iomap->offset += mdev.m_dax_part_off;
> +	} else {
> +		iomap->bdev = mdev.m_bdev;
> +	}
>  	iomap->length = map.m_llen;
>  	iomap->flags = 0;
>  	iomap->private = NULL;
> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
> index c1e65346e9f15..5c2a83876220c 100644
> --- a/fs/erofs/internal.h
> +++ b/fs/erofs/internal.h
> @@ -438,6 +438,7 @@ static inline int z_erofs_map_blocks_iter(struct inode *inode,
>  struct erofs_map_dev {
>  	struct block_device *m_bdev;
>  	struct dax_device *m_daxdev;
> +	u64 m_dax_part_off;
>  
>  	erofs_off_t m_pa;
>  	unsigned int m_deviceid;
> diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
> index 01d69618277de..602578b72d8c5 100644
> --- a/fs/ext2/inode.c
> +++ b/fs/ext2/inode.c
> @@ -817,9 +817,11 @@ static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
>  		return ret;
>  
>  	iomap->flags = 0;
> -	iomap->bdev = inode->i_sb->s_bdev;
>  	iomap->offset = (u64)first_block << blkbits;
> -	iomap->dax_dev = sbi->s_daxdev;
> +	if (flags & IOMAP_DAX)
> +		iomap->dax_dev = sbi->s_daxdev;
> +	else
> +		iomap->bdev = inode->i_sb->s_bdev;
>  
>  	if (ret == 0) {
>  		iomap->type = IOMAP_HOLE;
> @@ -828,6 +830,8 @@ static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
>  	} else {
>  		iomap->type = IOMAP_MAPPED;
>  		iomap->addr = (u64)bno << blkbits;
> +		if (flags & IOMAP_DAX)
> +			iomap->addr += sbi->s_dax_part_off;
>  		iomap->length = (u64)ret << blkbits;
>  		iomap->flags |= IOMAP_F_MERGED;
>  	}
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 89c4a174bd393..ccafcbc146d3e 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -3272,7 +3272,7 @@ static bool ext4_inode_datasync_dirty(struct inode *inode)
>  
>  static void ext4_set_iomap(struct inode *inode, struct iomap *iomap,
>  			   struct ext4_map_blocks *map, loff_t offset,
> -			   loff_t length)
> +			   loff_t length, unsigned int flags)
>  {
>  	u8 blkbits = inode->i_blkbits;
>  
> @@ -3289,8 +3289,10 @@ static void ext4_set_iomap(struct inode *inode, struct iomap *iomap,
>  	if (map->m_flags & EXT4_MAP_NEW)
>  		iomap->flags |= IOMAP_F_NEW;
>  
> -	iomap->bdev = inode->i_sb->s_bdev;
> -	iomap->dax_dev = EXT4_SB(inode->i_sb)->s_daxdev;
> +	if (flags & IOMAP_DAX)
> +		iomap->dax_dev = EXT4_SB(inode->i_sb)->s_daxdev;
> +	else
> +		iomap->bdev = inode->i_sb->s_bdev;
>  	iomap->offset = (u64) map->m_lblk << blkbits;
>  	iomap->length = (u64) map->m_len << blkbits;
>  
> @@ -3310,9 +3312,13 @@ static void ext4_set_iomap(struct inode *inode, struct iomap *iomap,
>  	if (map->m_flags & EXT4_MAP_UNWRITTEN) {
>  		iomap->type = IOMAP_UNWRITTEN;
>  		iomap->addr = (u64) map->m_pblk << blkbits;
> +		if (flags & IOMAP_DAX)
> +			iomap->addr += EXT4_SB(inode->i_sb)->s_dax_part_off;
>  	} else if (map->m_flags & EXT4_MAP_MAPPED) {
>  		iomap->type = IOMAP_MAPPED;
>  		iomap->addr = (u64) map->m_pblk << blkbits;
> +		if (flags & IOMAP_DAX)
> +			iomap->addr += EXT4_SB(inode->i_sb)->s_dax_part_off;
>  	} else {
>  		iomap->type = IOMAP_HOLE;
>  		iomap->addr = IOMAP_NULL_ADDR;
> @@ -3421,7 +3427,7 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
>  	if (ret < 0)
>  		return ret;
>  out:
> -	ext4_set_iomap(inode, iomap, &map, offset, length);
> +	ext4_set_iomap(inode, iomap, &map, offset, length, flags);
>  
>  	return 0;
>  }
> @@ -3541,7 +3547,7 @@ static int ext4_iomap_begin_report(struct inode *inode, loff_t offset,
>  		delalloc = ext4_iomap_is_delalloc(inode, &map);
>  
>  set_iomap:
> -	ext4_set_iomap(inode, iomap, &map, offset, length);
> +	ext4_set_iomap(inode, iomap, &map, offset, length, flags);
>  	if (delalloc && iomap->type == IOMAP_HOLE)
>  		iomap->type = IOMAP_DELALLOC;
>  
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index 0ed3e7674353b..e552ce541ec2d 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -71,15 +71,21 @@ xfs_bmbt_to_iomap(
>  		iomap->type = IOMAP_DELALLOC;
>  	} else {
>  		iomap->addr = BBTOB(xfs_fsb_to_db(ip, imap->br_startblock));
> +		if (mapping_flags & IOMAP_DAX)
> +			iomap->addr += target->bt_dax_part_off;
> +
>  		if (imap->br_state == XFS_EXT_UNWRITTEN)
>  			iomap->type = IOMAP_UNWRITTEN;
>  		else
>  			iomap->type = IOMAP_MAPPED;
> +
>  	}
>  	iomap->offset = XFS_FSB_TO_B(mp, imap->br_startoff);
>  	iomap->length = XFS_FSB_TO_B(mp, imap->br_blockcount);
> -	iomap->bdev = target->bt_bdev;
> -	iomap->dax_dev = target->bt_daxdev;
> +	if (mapping_flags & IOMAP_DAX)
> +		iomap->dax_dev = target->bt_daxdev;
> +	else
> +		iomap->bdev = target->bt_bdev;
>  	iomap->flags = iomap_flags;
>  
>  	if (xfs_ipincount(ip) &&
> -- 
> 2.30.2
>