[PATCH 4.19 024/421] ext4: fix avefreec in find_group_orlov

Greg Kroah-Hartman
2021-07-19T15:47:54Z

From: Pan Dong <pandong.peter@bytedance.com>

commit c89849cc0259f3d33624cc3bd127685c3c0fa25d upstream.

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

Cc: stable@kernel.org
Signed-off-by: Pan Dong <pandong.peter@bytedance.com>
Link: https://lore.kernel.org/r/20210525073656.31594-1-pandong.peter@bytedance.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/ext4/ialloc.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)

--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -399,7 +399,7 @@ static void get_orlov_stats(struct super
*
* 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.
*
@@ -408,7 +408,7 @@ static void get_orlov_stats(struct super
* 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
@@ -424,7 +424,7 @@ static int find_group_orlov(struct super
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;
@@ -443,9 +443,8 @@ static int find_group_orlov(struct super

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);