[PATCH v5 6/8] xfs: support write streams on realtime volumes

[Kanchan Joshi <joshi.k@samsung.com>]

From: Anuj Gupta <anuj20.g@samsung.com>

Enable write streams on non-zoned realtime volumes that have realtime
groups, partitioning RTGs among the streams as the AG side does.

Stream based RTG selection applies to the first allocation of a file;
later ones keep using the adjacent-allocation hint so the file stays
contiguous.

Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
---
 fs/xfs/xfs_inode.c   |  4 ++--
 fs/xfs/xfs_ioctl.c   |  3 ++-
 fs/xfs/xfs_rtalloc.c | 27 +++++++++++++++++++++++++++
 fs/xfs/xfs_super.c   |  7 +++++++
 4 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index df0a37c4d68a..c3503fe870ba 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -57,7 +57,7 @@ xfs_inode_max_write_streams(
 
 	if (xfs_inode_is_filestream(ip))
 		return 0;
-	if (XFS_IS_REALTIME_INODE(ip))
+	if (XFS_IS_REALTIME_INODE(ip) && xfs_has_zoned(ip->i_mount))
 		return 0;
 	return write_stream_pool_count(&xfs_inode_buftarg(ip)->bt_stream_pool);
 }
@@ -75,7 +75,7 @@ xfs_inode_set_write_stream(
 	if (!fd_file(f))
 		return -EBADF;
 	xfs_ilock(ip, XFS_ILOCK_EXCL);
-	if (XFS_IS_REALTIME_INODE(ip)) {
+	if (XFS_IS_REALTIME_INODE(ip) && xfs_has_zoned(ip->i_mount)) {
 		error = -EINVAL;
 		goto out_unlock;
 	}
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index bc6957ad06cb..4c0aff34e3c3 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -559,7 +559,8 @@ xfs_ioctl_setattr_xflags(
 
 	/* refuse a filestream/realtime flag change while a stream is attached */
 	if (READ_ONCE(VFS_I(ip)->i_write_stream) &&
-	    ((fa->fsx_xflags & FS_XFLAG_FILESTREAM) || rtflag))
+	    ((fa->fsx_xflags & FS_XFLAG_FILESTREAM) ||
+	     rtflag != XFS_IS_REALTIME_INODE(ip)))
 		return -EINVAL;
 
 	if (rtflag != XFS_IS_REALTIME_INODE(ip)) {
diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index 84efe5a8fb11..a291f1aca6eb 100644
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -2160,6 +2160,28 @@ xfs_rtallocate_align(
 	return 0;
 }
 
+static xfs_rtblock_t
+xfs_bmap_write_stream_rtbno(
+	struct xfs_inode	*ip,
+	unsigned int		stream_id)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	unsigned int		nr_rtgs = mp->m_sb.sb_rgcount;
+	unsigned int		nr_streams =
+		write_stream_pool_count(&mp->m_rtdev_targp->bt_stream_pool);
+	unsigned int		set_size = nr_rtgs / nr_streams;
+	xfs_rgnumber_t		start_rgno, target_rgno;
+
+	stream_id -= 1;	/* convert from 1-based to 0-based */
+	start_rgno = stream_id * set_size;
+	if (stream_id == nr_streams - 1)
+		set_size = nr_rtgs - start_rgno;
+	target_rgno = start_rgno + I_INO(ip) % set_size;
+
+	return (xfs_rtblock_t)target_rgno <<
+		mp->m_groups[XG_TYPE_RTG].blklog;
+}
+
 int
 xfs_bmap_rtalloc(
 	struct xfs_bmalloca	*ap)
@@ -2174,10 +2196,13 @@ xfs_bmap_rtalloc(
 	bool			noalign = false;
 	bool			initial_user_data =
 		ap->datatype & XFS_ALLOC_INITIAL_USER_DATA;
+	unsigned int		stream_id;
 	int			error;
 
 	ASSERT(!xfs_has_zoned(ap->tp->t_mountp));
 
+	stream_id = READ_ONCE(VFS_I(ap->ip)->i_write_stream);
+
 retry:
 	error = xfs_rtallocate_align(ap, &ralen, &raminlen, &prod, &noalign);
 	if (error)
@@ -2185,6 +2210,8 @@ xfs_bmap_rtalloc(
 
 	if (xfs_bmap_adjacent(ap))
 		bno_hint = ap->blkno;
+	else if (stream_id && xfs_has_rtgroups(ap->ip->i_mount))
+		bno_hint = xfs_bmap_write_stream_rtbno(ap->ip, stream_id);
 
 	if (xfs_has_rtgroups(ap->ip->i_mount)) {
 		error = xfs_rtallocate_rtgs(ap->tp, bno_hint, raminlen, ralen,
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 443b3d847150..5c92f8ebd8a7 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -637,6 +637,13 @@ xfs_setup_devices(
 		if (error)
 			return error;
 		xfs_update_bdi_rahead(mp);
+
+		if (xfs_has_rtgroups(mp) && !xfs_has_zoned(mp)) {
+			error = xfs_buftarg_init_streams(mp->m_rtdev_targp,
+					mp->m_sb.sb_rgcount);
+			if (error)
+				return error;
+		}
 	}
 
 	return 0;
-- 
2.25.1