[PATCH v5 1/3] btrfs: don't try to relocate the data relocation block-group

[Johannes Thumshirn]

From: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>

When relocating block-groups, either via auto reclaim or manual
balance, skip the data relocation block-group.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
---
 fs/btrfs/block-group.c | 2 ++
 fs/btrfs/relocation.c  | 7 +++++++
 fs/btrfs/volumes.c     | 2 ++
 3 files changed, 11 insertions(+)

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 9910bae89966..9a01bbad45f6 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -1921,6 +1921,8 @@ void btrfs_reclaim_bgs_work(struct work_struct *work)
 				div64_u64(zone_unusable * 100, bg->length));
 		trace_btrfs_reclaim_block_group(bg);
 		ret = btrfs_relocate_chunk(fs_info, bg->start);
+		if (ret == -EBUSY)
+			ret = 0;
 		if (ret) {
 			btrfs_dec_block_group_ro(bg);
 			btrfs_err(fs_info, "error relocating chunk %llu",
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 5f1a909a1d91..39e2db9af64f 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -4037,6 +4037,13 @@ int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
 	int rw = 0;
 	int err = 0;
 
+	spin_lock(&fs_info->relocation_bg_lock);
+	if (group_start == fs_info->data_reloc_bg) {
+		spin_unlock(&fs_info->relocation_bg_lock);
+		return -EBUSY;
+	}
+	spin_unlock(&fs_info->relocation_bg_lock);
+
 	/*
 	 * This only gets set if we had a half-deleted snapshot on mount.  We
 	 * cannot allow relocation to start while we're still trying to clean up
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 3f70f727dacf..75da3a32885b 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3367,6 +3367,8 @@ int btrfs_relocate_chunk(struct btrfs_fs_info *fs_info, u64 chunk_offset)
 	btrfs_scrub_pause(fs_info);
 	ret = btrfs_relocate_block_group(fs_info, chunk_offset);
 	btrfs_scrub_continue(fs_info);
+	if (ret == -EBUSY)
+		return 0;
 	if (ret) {
 		/*
 		 * If we had a transaction abort, stop all running scrubs.

-- 
2.43.0