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

Darrick J. Wong
2021-11-23T23:11:48Z

On Tue, Nov 09, 2021 at 09:33:06AM +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

As part of the ... ?

"...impending disentanglement of block_device and dax_device"?

Which I assume is why we make filesystems know about partition offsets
now?

> methods.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> 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/libxfs/xfs_bmap.c | 4 ++--
> fs/xfs/xfs_aops.c | 2 +-
> fs/xfs/xfs_iomap.c | 45 +++++++++++++++++++++++++---------------
> fs/xfs/xfs_iomap.h | 5 +++--
> fs/xfs/xfs_pnfs.c | 2 +-
> 10 files changed, 63 insertions(+), 37 deletions(-)
>
> diff --git a/fs/dax.c b/fs/dax.c
> index 0bd6cdcbacfc4..2c13c681edf09 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)

<skip to the xfs part, the ext* parts look ok and I didn't look at erofs>

> diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> index 4dccd4d90622d..74198dd82b035 100644
> --- a/fs/xfs/libxfs/xfs_bmap.c
> +++ b/fs/xfs/libxfs/xfs_bmap.c
> @@ -4551,7 +4551,7 @@ xfs_bmapi_convert_delalloc(
> * the extent. Just return the real extent at this offset.
> */
> if (!isnullstartblock(bma.got.br_startblock)) {
> - xfs_bmbt_to_iomap(ip, iomap, &bma.got, flags);
> + xfs_bmbt_to_iomap(ip, iomap, &bma.got, 0, flags);
> *seq = READ_ONCE(ifp->if_seq);
> goto out_trans_cancel;
> }
> @@ -4598,7 +4598,7 @@ xfs_bmapi_convert_delalloc(
> XFS_STATS_INC(mp, xs_xstrat_quick);
>
> ASSERT(!isnullstartblock(bma.got.br_startblock));
> - xfs_bmbt_to_iomap(ip, iomap, &bma.got, flags);
> + xfs_bmbt_to_iomap(ip, iomap, &bma.got, 0, flags);
> *seq = READ_ONCE(ifp->if_seq);
>
> if (whichfork == XFS_COW_FORK)
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index c8c15c3c31471..6ac3449a68ba0 100644
> --- a/fs/xfs/xfs_aops.c
> +++ b/fs/xfs/xfs_aops.c
> @@ -359,7 +359,7 @@ xfs_map_blocks(
> isnullstartblock(imap.br_startblock))
> goto allocate_blocks;
>
> - xfs_bmbt_to_iomap(ip, &wpc->iomap, &imap, 0);
> + xfs_bmbt_to_iomap(ip, &wpc->iomap, &imap, 0, 0);
> trace_xfs_map_blocks_found(ip, offset, count, whichfork, &imap);
> return 0;
> allocate_blocks:
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index 704292c6ce0c7..74dbf1fd99d39 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -54,7 +54,8 @@ xfs_bmbt_to_iomap(
> struct xfs_inode *ip,
> struct iomap *iomap,
> struct xfs_bmbt_irec *imap,
> - u16 flags)
> + unsigned int flags,
> + u16 iomap_flags)

The argument names confused me. Do @flags contains IOMAP_$FOO flags,
whereas @iomap_flags contains IOMAP_F_$FOO flags? Can these be changed
to "unsigned int iomap_flags" and "u16 iomap_f_flags" to make the flags
domain more obvious, please?

I'd also take "u16 mapping_flags" for the last parameter.

--D

> {
> struct xfs_mount *mp = ip->i_mount;
> struct xfs_buftarg *target = xfs_inode_buftarg(ip);
> @@ -71,16 +72,22 @@ xfs_bmbt_to_iomap(
> iomap->type = IOMAP_DELALLOC;
> } else {
> iomap->addr = BBTOB(xfs_fsb_to_db(ip, imap->br_startblock));
> + if (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;
> - iomap->flags = flags;
> + if (flags & IOMAP_DAX)
> + iomap->dax_dev = target->bt_daxdev;
> + else
> + iomap->bdev = target->bt_bdev;
> + iomap->flags = iomap_flags;
>
> if (xfs_ipincount(ip) &&
> (ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
> @@ -801,7 +808,7 @@ xfs_direct_write_iomap_begin(
>
> xfs_iunlock(ip, lockmode);
> trace_xfs_iomap_found(ip, offset, length, XFS_DATA_FORK, &imap);
> - return xfs_bmbt_to_iomap(ip, iomap, &imap, iomap_flags);
> + return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, iomap_flags);
>
> allocate_blocks:
> error = -EAGAIN;
> @@ -832,18 +839,19 @@ xfs_direct_write_iomap_begin(
> return error;
>
> trace_xfs_iomap_alloc(ip, offset, length, XFS_DATA_FORK, &imap);
> - return xfs_bmbt_to_iomap(ip, iomap, &imap, iomap_flags | IOMAP_F_NEW);
> + return xfs_bmbt_to_iomap(ip, iomap, &imap, flags,
> + iomap_flags | IOMAP_F_NEW);
>
> out_found_cow:
> xfs_iunlock(ip, lockmode);
> length = XFS_FSB_TO_B(mp, cmap.br_startoff + cmap.br_blockcount);
> trace_xfs_iomap_found(ip, offset, length - offset, XFS_COW_FORK, &cmap);
> if (imap.br_startblock != HOLESTARTBLOCK) {
> - error = xfs_bmbt_to_iomap(ip, srcmap, &imap, 0);
> + error = xfs_bmbt_to_iomap(ip, srcmap, &imap, flags, 0);
> if (error)
> return error;
> }
> - return xfs_bmbt_to_iomap(ip, iomap, &cmap, IOMAP_F_SHARED);
> + return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, IOMAP_F_SHARED);
>
> out_unlock:
> if (lockmode)
> @@ -1053,23 +1061,24 @@ xfs_buffered_write_iomap_begin(
> */
> xfs_iunlock(ip, XFS_ILOCK_EXCL);
> trace_xfs_iomap_alloc(ip, offset, count, allocfork, &imap);
> - return xfs_bmbt_to_iomap(ip, iomap, &imap, IOMAP_F_NEW);
> + return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, IOMAP_F_NEW);
>
> found_imap:
> xfs_iunlock(ip, XFS_ILOCK_EXCL);
> - return xfs_bmbt_to_iomap(ip, iomap, &imap, 0);
> + return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0);
>
> found_cow:
> xfs_iunlock(ip, XFS_ILOCK_EXCL);
> if (imap.br_startoff <= offset_fsb) {
> - error = xfs_bmbt_to_iomap(ip, srcmap, &imap, 0);
> + error = xfs_bmbt_to_iomap(ip, srcmap, &imap, flags, 0);
> if (error)
> return error;
> - return xfs_bmbt_to_iomap(ip, iomap, &cmap, IOMAP_F_SHARED);
> + return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags,
> + IOMAP_F_SHARED);
> }
>
> xfs_trim_extent(&cmap, offset_fsb, imap.br_startoff - offset_fsb);
> - return xfs_bmbt_to_iomap(ip, iomap, &cmap, 0);
> + return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, 0);
>
> out_unlock:
> xfs_iunlock(ip, XFS_ILOCK_EXCL);
> @@ -1178,7 +1187,8 @@ xfs_read_iomap_begin(
> if (error)
> return error;
> trace_xfs_iomap_found(ip, offset, length, XFS_DATA_FORK, &imap);
> - return xfs_bmbt_to_iomap(ip, iomap, &imap, shared ? IOMAP_F_SHARED : 0);
> + return xfs_bmbt_to_iomap(ip, iomap, &imap, flags,
> + shared ? IOMAP_F_SHARED : 0);
> }
>
> const struct iomap_ops xfs_read_iomap_ops = {
> @@ -1237,7 +1247,8 @@ xfs_seek_iomap_begin(
> if (data_fsb < cow_fsb + cmap.br_blockcount)
> end_fsb = min(end_fsb, data_fsb);
> xfs_trim_extent(&cmap, offset_fsb, end_fsb);
> - error = xfs_bmbt_to_iomap(ip, iomap, &cmap, IOMAP_F_SHARED);
> + error = xfs_bmbt_to_iomap(ip, iomap, &cmap, flags,
> + IOMAP_F_SHARED);
> /*
> * This is a COW extent, so we must probe the page cache
> * because there could be dirty page cache being backed
> @@ -1259,7 +1270,7 @@ xfs_seek_iomap_begin(
> imap.br_state = XFS_EXT_NORM;
> done:
> xfs_trim_extent(&imap, offset_fsb, end_fsb);
> - error = xfs_bmbt_to_iomap(ip, iomap, &imap, 0);
> + error = xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0);
> out_unlock:
> xfs_iunlock(ip, lockmode);
> return error;
> @@ -1306,7 +1317,7 @@ xfs_xattr_iomap_begin(
> if (error)
> return error;
> ASSERT(nimaps);
> - return xfs_bmbt_to_iomap(ip, iomap, &imap, 0);
> + return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0);
> }
>
> const struct iomap_ops xfs_xattr_iomap_ops = {
> diff --git a/fs/xfs/xfs_iomap.h b/fs/xfs/xfs_iomap.h
> index 5648262a71736..fe7a625361d95 100644
> --- a/fs/xfs/xfs_iomap.h
> +++ b/fs/xfs/xfs_iomap.h
> @@ -18,8 +18,9 @@ int xfs_iomap_write_unwritten(struct xfs_inode *, xfs_off_t, xfs_off_t, bool);
> xfs_fileoff_t xfs_iomap_eof_align_last_fsb(struct xfs_inode *ip,
> xfs_fileoff_t end_fsb);
>
> -int xfs_bmbt_to_iomap(struct xfs_inode *, struct iomap *,
> - struct xfs_bmbt_irec *, u16);
> +int xfs_bmbt_to_iomap(struct xfs_inode *ip, struct iomap *iomap,
> + struct xfs_bmbt_irec *imap, unsigned int flags,
> + u16 iomap_flags);
>
> int xfs_zero_range(struct xfs_inode *ip, loff_t pos, loff_t len,
> bool *did_zero);
> diff --git a/fs/xfs/xfs_pnfs.c b/fs/xfs/xfs_pnfs.c
> index e188e1cf97cc5..d6334abbc0b3e 100644
> --- a/fs/xfs/xfs_pnfs.c
> +++ b/fs/xfs/xfs_pnfs.c
> @@ -173,7 +173,7 @@ xfs_fs_map_blocks(
> }
> xfs_iunlock(ip, XFS_IOLOCK_EXCL);
>
> - error = xfs_bmbt_to_iomap(ip, iomap, &imap, 0);
> + error = xfs_bmbt_to_iomap(ip, iomap, &imap, 0, 0);
> *device_generation = mp->m_generation;
> return error;
> out_unlock:
> --
> 2.30.2
>