[PATCH] ext4: fix avefreec in find_group_orlov

[PATCH] ext4: fix avefreec in find_group_orlov

[Pan Dong]

The avefreec should be average free clusters instead
of average free blocks, otherwize Orlov's allocator
will not work properly when bigalloc enabled.

Signed-off-by: Pan Dong <pandong.peter@bytedance.com>
---
 fs/ext4/ialloc.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 71d321b3b984..6c6b6855e30d 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -400,7 +400,7 @@ static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
  *
  * We always try to spread first-level directories.
  *
- * If there are blockgroups with both free inodes and free blocks counts
+ * If there are blockgroups with both free inodes and free clusters counts
  * not worse than average we return one with smallest directory count.
  * Otherwise we simply return a random group.
  *
@@ -409,7 +409,7 @@ static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
  * It's OK to put directory into a group unless
  * it has too many directories already (max_dirs) or
  * it has too few free inodes left (min_inodes) or
- * it has too few free blocks left (min_blocks) or
+ * it has too few free clusters left (min_clusters) or
  * Parent's group is preferred, if it doesn't satisfy these
  * conditions we search cyclically through the rest. If none
  * of the groups look good we just look for a group with more
@@ -425,7 +425,7 @@ static int find_group_orlov(struct super_block *sb, struct inode *parent,
 	ext4_group_t real_ngroups = ext4_get_groups_count(sb);
 	int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
 	unsigned int freei, avefreei, grp_free;
-	ext4_fsblk_t freeb, avefreec;
+	ext4_fsblk_t freec, avefreec;
 	unsigned int ndirs;
 	int max_dirs, min_inodes;
 	ext4_grpblk_t min_clusters;
@@ -444,9 +444,8 @@ static int find_group_orlov(struct super_block *sb, struct inode *parent,
 
 	freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
 	avefreei = freei / ngroups;
-	freeb = EXT4_C2B(sbi,
-		percpu_counter_read_positive(&sbi->s_freeclusters_counter));
-	avefreec = freeb;
+	freec = percpu_counter_read_positive(&sbi->s_freeclusters_counter);
+	avefreec = freec;
 	do_div(avefreec, ngroups);
 	ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
 
-- 
2.20.1

Re: [PATCH] ext4: fix avefreec in find_group_orlov

[Theodore Ts'o]

On Tue, May 25, 2021 at 03:36:56PM +0800, Pan Dong wrote:
> The avefreec should be average free clusters instead
> of average free blocks, otherwize Orlov's allocator
> will not work properly when bigalloc enabled.
> 
> Signed-off-by: Pan Dong <pandong.peter@bytedance.com>

Applied, thanks.

				- Ted