ext4: Use atomic_t's in struct flex_groups
Reduce pressure on the sb_bgl_lock family of locks by using atomic_t's
to track the number of free blocks and inodes in each flex_group.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index c06886a..546c7dd 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -938,10 +938,10 @@
if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
ext4_group_t flex_group;
flex_group = ext4_flex_group(sbi, input->group);
- sbi->s_flex_groups[flex_group].free_blocks +=
- input->free_blocks_count;
- sbi->s_flex_groups[flex_group].free_inodes +=
- EXT4_INODES_PER_GROUP(sb);
+ atomic_add(input->free_blocks_count,
+ &sbi->s_flex_groups[flex_group].free_blocks);
+ atomic_add(EXT4_INODES_PER_GROUP(sb),
+ &sbi->s_flex_groups[flex_group].free_inodes);
}
ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);