[PATCH v5 24/28] btrfs: enable relocation in HMZONED mode

[Naohiro Aota <naohiro.aota@wdc.com>]

To serialize allocation and submit_bio, we introduced mutex around them. As
a result, preallocation must be completely disabled to avoid a deadlock.

Since current relocation process relies on preallocation to move file data
extents, it must be handled in another way. In HMZONED mode, we just
truncate the inode to the size that we wanted to pre-allocate. Then, we
flush dirty pages on the file before finishing relocation process.
run_delalloc_hmzoned() will handle all the allocation and submit IOs to
the underlying layers.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/relocation.c | 39 +++++++++++++++++++++++++++++++++++++--
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index d897a8e5e430..2d17b7566df4 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -3159,6 +3159,34 @@ int prealloc_file_extent_cluster(struct inode *inode,
 	if (ret)
 		goto out;
 
+	/*
+	 * In HMZONED, we cannot preallocate the file region. Instead,
+	 * we dirty and fiemap_write the region.
+	 */
+
+	if (btrfs_fs_incompat(btrfs_sb(inode->i_sb), HMZONED)) {
+		struct btrfs_root *root = BTRFS_I(inode)->root;
+		struct btrfs_trans_handle *trans;
+
+		end = cluster->end - offset + 1;
+		trans = btrfs_start_transaction(root, 1);
+		if (IS_ERR(trans))
+			return PTR_ERR(trans);
+
+		inode->i_ctime = current_time(inode);
+		i_size_write(inode, end);
+		btrfs_ordered_update_i_size(inode, end, NULL);
+		ret = btrfs_update_inode(trans, root, inode);
+		if (ret) {
+			btrfs_abort_transaction(trans, ret);
+			btrfs_end_transaction(trans);
+			return ret;
+		}
+		ret = btrfs_end_transaction(trans);
+
+		goto out;
+	}
+
 	cur_offset = prealloc_start;
 	while (nr < cluster->nr) {
 		start = cluster->boundary[nr] - offset;
@@ -3346,6 +3374,10 @@ static int relocate_file_extent_cluster(struct inode *inode,
 		btrfs_throttle(fs_info);
 	}
 	WARN_ON(nr != cluster->nr);
+	if (btrfs_fs_incompat(fs_info, HMZONED) && !ret) {
+		ret = btrfs_wait_ordered_range(inode, 0, (u64)-1);
+		WARN_ON(ret);
+	}
 out:
 	kfree(ra);
 	return ret;
@@ -4186,8 +4218,12 @@ static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
 	struct btrfs_path *path;
 	struct btrfs_inode_item *item;
 	struct extent_buffer *leaf;
+	u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC;
 	int ret;
 
+	if (btrfs_fs_incompat(trans->fs_info, HMZONED))
+		flags &= ~BTRFS_INODE_PREALLOC;
+
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
@@ -4202,8 +4238,7 @@ static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
 	btrfs_set_inode_generation(leaf, item, 1);
 	btrfs_set_inode_size(leaf, item, 0);
 	btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
-	btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
-					  BTRFS_INODE_PREALLOC);
+	btrfs_set_inode_flags(leaf, item, flags);
 	btrfs_mark_buffer_dirty(leaf);
 out:
 	btrfs_free_path(path);
-- 
2.24.0