[PATCH] Btrfs: remove level==0 check in balance_level

btrfs_search_slot()
   if (level != 0)
      setup_nodes_for_search()
          balance_level()

It is just impossible to have level=0 in balance_level.

Signed-off-by: Liu Bo <redacted>
---
 fs/btrfs/ctree.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 8b31caa60b0a..858085490e23 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c

@@ -1778,9 +1778,6 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 	int orig_slot = path->slots[level];
 	u64 orig_ptr;
 
-	if (level == 0)
-		return 0;
-
 	mid = path->nodes[level];
 
 	WARN_ON(path->locks[level] != BTRFS_WRITE_LOCK &&

-- 
1.8.3.1

On 12.09.2018 01:06, Liu Bo wrote:

btrfs_search_slot()
   if (level != 0)
      setup_nodes_for_search()
          balance_level()

It is just impossible to have level=0 in balance_level.

Signed-off-by: Liu Bo <redacted>

I concur with the analysis:

Reviewed-by: Nikolay Borisov <redacted>

On Wed, Sep 12, 2018 at 06:06:23AM +0800, Liu Bo wrote:

btrfs_search_slot()
   if (level != 0)
      setup_nodes_for_search()
          balance_level()

It is just impossible to have level=0 in balance_level.

While this is true, what do you think about adding ASSERT(level > 0) ?
This is to catch accidentally passing level 0.

On Wed, Sep 12, 2018 at 02:52:38PM +0200, David Sterba wrote:

On Wed, Sep 12, 2018 at 06:06:23AM +0800, Liu Bo wrote:

quoted

btrfs_search_slot()
   if (level != 0)
      setup_nodes_for_search()
          balance_level()

It is just impossible to have level=0 in balance_level.

While this is true, what do you think about adding ASSERT(level > 0) ?
This is to catch accidentally passing level 0.

Sounds good, will update it.

thanks,
-liubo

btrfs_search_slot()
   if (level != 0)
      setup_nodes_for_search()
          balance_level()

It is just impossible to have level=0 in balance_level.

Reviewed-by: Nikolay Borisov <redacted>
Signed-off-by: Liu Bo <redacted>
---
v2: add assertion for level just in case someone breaks the rule in the
future.

 fs/btrfs/ctree.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 8b31caa60b0a..ada44c786f2e 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c

@@ -1778,8 +1778,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 	int orig_slot = path->slots[level];
 	u64 orig_ptr;
 
-	if (level == 0)
-		return 0;
+	ASSERT(level > 0);
 
 	mid = path->nodes[level];
 

-- 
1.8.3.1

On Fri, Sep 14, 2018 at 01:55:59AM +0800, Liu Bo wrote:

btrfs_search_slot()
   if (level != 0)
      setup_nodes_for_search()
          balance_level()

It is just impossible to have level=0 in balance_level.

Reviewed-by: Nikolay Borisov <redacted>
Signed-off-by: Liu Bo <redacted>

Reviewed-by: David Sterba <dsterba@suse.com>