[PATCH v3 6/7] ext4: Enable support for ext4 multi-fsblock atomic write using bigalloc

["Ritesh Harjani (IBM)" <ritesh.list@xxxxxxxxx>]

Last couple of patches added the needed support for multi-fsblock atomic
writes using bigalloc. This patch ensures that filesystem advertizes the
needed atomic write unit min and max values for enabling multi-fsblock
atomic write support with bigalloc.

Co-developed-by: Ojaswin Mujoo <ojaswin@xxxxxxxxxxxxx>
Signed-off-by: Ojaswin Mujoo <ojaswin@xxxxxxxxxxxxx>
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
---
 fs/ext4/super.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 181934499624..508ea5cff1c7 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4442,12 +4442,12 @@ static int ext4_handle_clustersize(struct super_block *sb)
 /*
  * ext4_atomic_write_init: Initializes filesystem min & max atomic write units.
  * @sb: super block
- * TODO: Later add support for bigalloc
  */
 static void ext4_atomic_write_init(struct super_block *sb)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	struct block_device *bdev = sb->s_bdev;
+	unsigned int clustersize = sb->s_blocksize;
 
 	if (!bdev_can_atomic_write(bdev))
 		return;
@@ -4455,9 +4455,12 @@ static void ext4_atomic_write_init(struct super_block *sb)
 	if (!ext4_has_feature_extents(sb))
 		return;
 
+	if (ext4_has_feature_bigalloc(sb))
+		clustersize = EXT4_CLUSTER_SIZE(sb);
+
 	sbi->s_awu_min = max(sb->s_blocksize,
 			      bdev_atomic_write_unit_min_bytes(bdev));
-	sbi->s_awu_max = min(sb->s_blocksize,
+	sbi->s_awu_max = min(clustersize,
 			      bdev_atomic_write_unit_max_bytes(bdev));
 	if (sbi->s_awu_min && sbi->s_awu_max &&
 	    sbi->s_awu_min <= sbi->s_awu_max) {
-- 
2.49.0