On Mon, Sep 09, 2019 at 08:27:17PM +0200, Christoph Hellwig wrote:
> Start untangling xfs_file_iomap_begin by splitting out the read-only
> case into its own set of iomap_ops with a very simply iomap_begin
> helper.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Looks ok,
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
--D
> ---
> fs/xfs/xfs_aops.c | 9 ++++---
> fs/xfs/xfs_file.c | 8 +++---
> fs/xfs/xfs_iomap.c | 61 ++++++++++++++++++++++++++++++++++------------
> fs/xfs/xfs_iomap.h | 1 +
> fs/xfs/xfs_iops.c | 2 +-
> 5 files changed, 58 insertions(+), 23 deletions(-)
>
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index 4e4a4d7df5ac..fe47a4d52247 100644
> --- a/fs/xfs/xfs_aops.c
> +++ b/fs/xfs/xfs_aops.c
> @@ -1158,7 +1158,7 @@ xfs_vm_bmap(
> */
> if (xfs_is_cow_inode(ip) || XFS_IS_REALTIME_INODE(ip))
> return 0;
> - return iomap_bmap(mapping, block, &xfs_iomap_ops);
> + return iomap_bmap(mapping, block, &xfs_read_iomap_ops);
> }
>
> STATIC int
> @@ -1167,7 +1167,7 @@ xfs_vm_readpage(
> struct page *page)
> {
> trace_xfs_vm_readpage(page->mapping->host, 1);
> - return iomap_readpage(page, &xfs_iomap_ops);
> + return iomap_readpage(page, &xfs_read_iomap_ops);
> }
>
> STATIC int
> @@ -1178,7 +1178,7 @@ xfs_vm_readpages(
> unsigned nr_pages)
> {
> trace_xfs_vm_readpages(mapping->host, nr_pages);
> - return iomap_readpages(mapping, pages, nr_pages, &xfs_iomap_ops);
> + return iomap_readpages(mapping, pages, nr_pages, &xfs_read_iomap_ops);
> }
>
> static int
> @@ -1188,7 +1188,8 @@ xfs_iomap_swapfile_activate(
> sector_t *span)
> {
> sis->bdev = xfs_find_bdev_for_inode(file_inode(swap_file));
> - return iomap_swapfile_activate(sis, swap_file, span, &xfs_iomap_ops);
> + return iomap_swapfile_activate(sis, swap_file, span,
> + &xfs_read_iomap_ops);
> }
>
> const struct address_space_operations xfs_address_space_operations = {
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 21bd3d575aaa..d8e2e36b84f7 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -187,7 +187,7 @@ xfs_file_dio_aio_read(
> file_accessed(iocb->ki_filp);
>
> xfs_ilock(ip, XFS_IOLOCK_SHARED);
> - ret = iomap_dio_rw(iocb, to, &xfs_iomap_ops, NULL);
> + ret = iomap_dio_rw(iocb, to, &xfs_read_iomap_ops, NULL);
> xfs_iunlock(ip, XFS_IOLOCK_SHARED);
>
> return ret;
> @@ -214,7 +214,7 @@ xfs_file_dax_read(
> xfs_ilock(ip, XFS_IOLOCK_SHARED);
> }
>
> - ret = dax_iomap_rw(iocb, to, &xfs_iomap_ops);
> + ret = dax_iomap_rw(iocb, to, &xfs_read_iomap_ops);
> xfs_iunlock(ip, XFS_IOLOCK_SHARED);
>
> file_accessed(iocb->ki_filp);
> @@ -1131,7 +1131,9 @@ __xfs_filemap_fault(
> if (IS_DAX(inode)) {
> pfn_t pfn;
>
> - ret = dax_iomap_fault(vmf, pe_size, &pfn, NULL, &xfs_iomap_ops);
> + ret = dax_iomap_fault(vmf, pe_size, &pfn, NULL,
> + (write_fault && !vmf->cow_page) ?
> + &xfs_iomap_ops : &xfs_read_iomap_ops);
> if (ret & VM_FAULT_NEEDDSYNC)
> ret = dax_finish_sync_fault(vmf, pe_size, pfn);
> } else {
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index 0ba67a8d8169..d0ed0cba9041 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -950,11 +950,13 @@ xfs_file_iomap_begin(
> u16 iomap_flags = 0;
> unsigned lockmode;
>
> + ASSERT(flags & (IOMAP_WRITE | IOMAP_ZERO));
> +
> if (XFS_FORCED_SHUTDOWN(mp))
> return -EIO;
>
> - if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && !(flags & IOMAP_DIRECT) &&
> - !IS_DAX(inode) && !xfs_get_extsz_hint(ip)) {
> + if (!(flags & IOMAP_DIRECT) && !IS_DAX(inode) &&
> + !xfs_get_extsz_hint(ip)) {
> /* Reserve delalloc blocks for regular writeback. */
> return xfs_file_iomap_begin_delay(inode, offset, length, flags,
> iomap, srcmap);
> @@ -975,17 +977,6 @@ xfs_file_iomap_begin(
> if (error)
> goto out_unlock;
>
> - if (flags & IOMAP_REPORT) {
> - /* Trim the mapping to the nearest shared extent boundary. */
> - error = xfs_reflink_trim_around_shared(ip, &imap, &shared);
> - if (error)
> - goto out_unlock;
> - }
> -
> - /* Non-modifying mapping requested, so we are done */
> - if (!(flags & (IOMAP_WRITE | IOMAP_ZERO)))
> - goto out_found;
> -
> /*
> * Break shared extents if necessary. Checks for non-blocking IO have
> * been done up front, so we don't need to do them here.
> @@ -1046,8 +1037,6 @@ xfs_file_iomap_begin(
> trace_xfs_iomap_alloc(ip, offset, length, XFS_DATA_FORK, &imap);
>
> out_finish:
> - if (shared)
> - iomap_flags |= IOMAP_F_SHARED;
> return xfs_bmbt_to_iomap(ip, iomap, &imap, iomap_flags);
>
> out_found:
> @@ -1150,6 +1139,48 @@ const struct iomap_ops xfs_iomap_ops = {
> .iomap_end = xfs_file_iomap_end,
> };
>
> +static int
> +xfs_read_iomap_begin(
> + struct inode *inode,
> + loff_t offset,
> + loff_t length,
> + unsigned flags,
> + struct iomap *iomap,
> + struct iomap *srcmap)
> +{
> + struct xfs_inode *ip = XFS_I(inode);
> + struct xfs_mount *mp = ip->i_mount;
> + struct xfs_bmbt_irec imap;
> + xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
> + xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, length);
> + int nimaps = 1, error = 0;
> + bool shared = false;
> + unsigned lockmode;
> +
> + ASSERT(!(flags & (IOMAP_WRITE | IOMAP_ZERO)));
> +
> + if (XFS_FORCED_SHUTDOWN(mp))
> + return -EIO;
> +
> + error = xfs_ilock_for_iomap(ip, flags, &lockmode);
> + if (error)
> + return error;
> + error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
> + &nimaps, 0);
> + if (!error && (flags & IOMAP_REPORT))
> + error = xfs_reflink_trim_around_shared(ip, &imap, &shared);
> + xfs_iunlock(ip, lockmode);
> +
> + 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);
> +}
> +
> +const struct iomap_ops xfs_read_iomap_ops = {
> + .iomap_begin = xfs_read_iomap_begin,
> +};
> +
> static int
> xfs_seek_iomap_begin(
> struct inode *inode,
> diff --git a/fs/xfs/xfs_iomap.h b/fs/xfs/xfs_iomap.h
> index 71d0ae460c44..61b1fc3e5143 100644
> --- a/fs/xfs/xfs_iomap.h
> +++ b/fs/xfs/xfs_iomap.h
> @@ -40,6 +40,7 @@ xfs_aligned_fsb_count(
> }
>
> extern const struct iomap_ops xfs_iomap_ops;
> +extern const struct iomap_ops xfs_read_iomap_ops;
> extern const struct iomap_ops xfs_seek_iomap_ops;
> extern const struct iomap_ops xfs_xattr_iomap_ops;
>
> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> index ff3c1fae5357..f0c7df82e18b 100644
> --- a/fs/xfs/xfs_iops.c
> +++ b/fs/xfs/xfs_iops.c
> @@ -1113,7 +1113,7 @@ xfs_vn_fiemap(
> &xfs_xattr_iomap_ops);
> } else {
> error = iomap_fiemap(inode, fieinfo, start, length,
> - &xfs_iomap_ops);
> + &xfs_read_iomap_ops);
> }
> xfs_iunlock(XFS_I(inode), XFS_IOLOCK_SHARED);
>
> --
> 2.20.1
>
