[PATCH v3 0/2] btrfs: Set relative data on clear btrfs_block_group_cache->pinned

[PATCH v3 0/2] btrfs: Set relative data on clear btrfs_block_group_cache->pinned

[Zhaolei]

From: Zhao Lei <zhaolei@cn.fujitsu.com>

Changelog v1->v2:
 [PATCH 2/2] btrfs: add WARN_ON() to check is space_info op current
   Put WARN_ON()s under the ENOSPC_DEBUG mount option.
   Suggested by: David Sterba <dsterba@suse.cz>

Changelog v1->v2:
 drop patch of:
  Remove BUG_ON() when failed searching block_group_cache in unpin_extent_range()
  because Filipe Manana <fdmanana@suse.com> already fixed it with  better way.

Zhao Lei (2):
  btrfs: Set relative data on clear btrfs_block_group_cache->pinned
  btrfs: add WARN_ON() to check is space_info op current

 fs/btrfs/extent-tree.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

-- 
1.8.5.1

[PATCH v3 1/2] btrfs: Set relative data on clear btrfs_block_group_cache->pinned

[Zhaolei]

From: Zhao Lei <zhaolei@cn.fujitsu.com>

Bug1:
  space_info->bytes_readonly was set to very large(negative) value in
  btrfs_remove_block_group().

Reason:
  Current code set block_group_cache->pinned = 0 in btrfs_delete_unused_bgs(),
  but above space was not counted to space_info->bytes_readonly.

  Then in btrfs_remove_block_group():
    block_group->space_info->bytes_readonly -= block_group->key.offset;
  We can see following value in trace:
    btrfs_remove_block_group: pid=2677 comm=btrfs-cleaner WARNING: bytes_readonly=12582912, key.offset=134217728

Bug2:
  space_info->total_bytes_pinned grow to value larger than fs size.
  In a 1.2G fs, we can get following trace log:
  at first:
    ZL_DEBUG: add_pinned_bytes: pid=2710 comm=sync change total_bytes_pinned flags=1 869793792 + 95944704 = 965738496
  after some op:
    ZL_DEBUG: add_pinned_bytes: pid=2770 comm=sync change total_bytes_pinned flags=1 1780178944 + 95944704 = 1876123648
  after some op:
    ZL_DEBUG: add_pinned_bytes: pid=3193 comm=sync change total_bytes_pinned flags=1 2924568576 + 95551488 = 3020120064
  ...

Reason:
  Similar to bug1, we also need to adjust space_info->total_bytes_pinned
  in above code block.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
---
 fs/btrfs/extent-tree.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index dc25e13..bfb9105 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -9605,8 +9605,18 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
 		mutex_unlock(&fs_info->unused_bg_unpin_mutex);
 
 		/* Reset pinned so btrfs_put_block_group doesn't complain */
+		spin_lock(&space_info->lock);
+		spin_lock(&block_group->lock);
+
+		space_info->bytes_pinned -= block_group->pinned;
+		space_info->bytes_readonly += block_group->pinned;
+		percpu_counter_add(&space_info->total_bytes_pinned,
+				   -block_group->pinned);
 		block_group->pinned = 0;
 
+		spin_unlock(&block_group->lock);
+		spin_unlock(&space_info->lock);
+
 		/*
 		 * Btrfs_remove_chunk will abort the transaction if things go
 		 * horribly wrong.
-- 
1.8.5.1

[PATCH v3 2/2] btrfs: add WARN_ON() to check is space_info op current

[Zhaolei]

From: Zhao Lei <zhaolei@cn.fujitsu.com>

space_info's value calculation is some complex and easy to cause
bug, add WARN_ON() to help debug.

Changelog v1->v2:
 Put WARN_ON()s under the ENOSPC_DEBUG mount option.
 Suggested by: David Sterba <dsterba@suse.cz>

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
---
 fs/btrfs/extent-tree.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index bfb9105..6c19033 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -9415,9 +9415,19 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 
 	spin_lock(&block_group->space_info->lock);
 	list_del_init(&block_group->ro_list);
+
+	if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
+		WARN_ON(block_group->space_info->total_bytes
+			< block_group->key.offset);
+		WARN_ON(block_group->space_info->bytes_readonly
+			< block_group->key.offset);
+		WARN_ON(block_group->space_info->disk_total
+			< block_group->key.offset * factor);
+	}
 	block_group->space_info->total_bytes -= block_group->key.offset;
 	block_group->space_info->bytes_readonly -= block_group->key.offset;
 	block_group->space_info->disk_total -= block_group->key.offset * factor;
+
 	spin_unlock(&block_group->space_info->lock);
 
 	memcpy(&key, &block_group->key, sizeof(key));
-- 
1.8.5.1