diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 36fa20e81a3a..5fd62a0f28b6 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1166,10 +1166,6 @@ struct ext4_inode_info {
 #define	EXT4_VALID_FS			0x0001	/* Unmounted cleanly */
 #define	EXT4_ERROR_FS			0x0002	/* Errors detected */
 #define	EXT4_ORPHAN_FS			0x0004	/* Orphans being recovered */
-#define EXT4_FC_INELIGIBLE		0x0008	/* Fast commit ineligible */
-#define EXT4_FC_COMMITTING		0x0010	/* File system underoing a fast
-						 * commit.
-						 */
 #define EXT4_FC_REPLAY			0x0020	/* Fast commit replay ongoing */
 
 /*
@@ -1431,6 +1427,10 @@ struct ext4_super_block {
  */
 #define EXT4_MF_MNTDIR_SAMPLED		0x0001
 #define EXT4_MF_FS_ABORTED		0x0002	/* Fatal error detected */
+#define EXT4_MF_FC_INELIGIBLE		0x0004	/* Fast commit ineligible */
+#define EXT4_MF_FC_COMMITTING		0x0008	/* File system underoing a fast
+						 * commit.
+						 */
 
 #ifdef CONFIG_FS_ENCRYPTION
 #define DUMMY_ENCRYPTION_ENABLED(sbi) ((sbi)->s_dummy_enc_policy.policy != NULL)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 559100f3e23c..57cfa28919a9 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -1471,16 +1471,16 @@ static int ext4_ext_search_left(struct inode *inode,
 }
 
 /*
- * search the closest allocated block to the right for *logical
- * and returns it at @logical + it's physical address at @phys
- * if *logical is the largest allocated block, the function
- * returns 0 at @phys
- * return value contains 0 (success) or error code
+ * Search the closest allocated block to the right for *logical
+ * and returns it at @logical + it's physical address at @phys.
+ * If not exists, return 0 and @phys is set to 0. We will return
+ * 1 which means we found an allocated block and ret_ex is valid.
+ * Or return a (< 0) error code.
  */
 static int ext4_ext_search_right(struct inode *inode,
 				 struct ext4_ext_path *path,
 				 ext4_lblk_t *logical, ext4_fsblk_t *phys,
-				 struct ext4_extent **ret_ex)
+				 struct ext4_extent *ret_ex)
 {
 	struct buffer_head *bh = NULL;
 	struct ext4_extent_header *eh;
@@ -1574,10 +1574,11 @@ got_index:
 found_extent:
 	*logical = le32_to_cpu(ex->ee_block);
 	*phys = ext4_ext_pblock(ex);
-	*ret_ex = ex;
+	if (ret_ex)
+		*ret_ex = *ex;
 	if (bh)
 		put_bh(bh);
-	return 0;
+	return 1;
 }
 
 /*
@@ -2868,8 +2869,8 @@ again:
 			 */
 			lblk = ex_end + 1;
 			err = ext4_ext_search_right(inode, path, &lblk, &pblk,
-						    &ex);
-			if (err)
+						    NULL);
+			if (err < 0)
 				goto out;
 			if (pblk) {
 				partial.pclu = EXT4_B2C(sbi, pblk);
@@ -4039,7 +4040,7 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
 			struct ext4_map_blocks *map, int flags)
 {
 	struct ext4_ext_path *path = NULL;
-	struct ext4_extent newex, *ex, *ex2;
+	struct ext4_extent newex, *ex, ex2;
 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 	ext4_fsblk_t newblock = 0, pblk;
 	int err = 0, depth, ret;
@@ -4175,15 +4176,14 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
 	if (err)
 		goto out;
 	ar.lright = map->m_lblk;
-	ex2 = NULL;
 	err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
-	if (err)
+	if (err < 0)
 		goto out;
 
 	/* Check if the extent after searching to the right implies a
 	 * cluster we can use. */
-	if ((sbi->s_cluster_ratio > 1) && ex2 &&
-	    get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
+	if ((sbi->s_cluster_ratio > 1) && err &&
+	    get_implied_cluster_alloc(inode->i_sb, map, &ex2, path)) {
 		ar.len = allocated = map->m_len;
 		newblock = map->m_pblk;
 		goto got_allocated_blocks;
diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index 447c8d93f480..8d43058386c3 100644
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -269,7 +269,7 @@ void ext4_fc_mark_ineligible(struct super_block *sb, int reason)
 	    (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))
 		return;
 
-	sbi->s_mount_state |= EXT4_FC_INELIGIBLE;
+	sbi->s_mount_flags |= EXT4_MF_FC_INELIGIBLE;
 	WARN_ON(reason >= EXT4_FC_REASON_MAX);
 	sbi->s_fc_stats.fc_ineligible_reason_count[reason]++;
 }
@@ -292,7 +292,7 @@ void ext4_fc_start_ineligible(struct super_block *sb, int reason)
 }
 
 /*
- * Stop a fast commit ineligible update. We set EXT4_FC_INELIGIBLE flag here
+ * Stop a fast commit ineligible update. We set EXT4_MF_FC_INELIGIBLE flag here
  * to ensure that after stopping the ineligible update, at least one full
  * commit takes place.
  */
@@ -302,13 +302,13 @@ void ext4_fc_stop_ineligible(struct super_block *sb)
 	    (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))
 		return;
 
-	EXT4_SB(sb)->s_mount_state |= EXT4_FC_INELIGIBLE;
+	EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FC_INELIGIBLE;
 	atomic_dec(&EXT4_SB(sb)->s_fc_ineligible_updates);
 }
 
 static inline int ext4_fc_is_ineligible(struct super_block *sb)
 {
-	return (EXT4_SB(sb)->s_mount_state & EXT4_FC_INELIGIBLE) ||
+	return (EXT4_SB(sb)->s_mount_flags & EXT4_MF_FC_INELIGIBLE) ||
 		atomic_read(&EXT4_SB(sb)->s_fc_ineligible_updates);
 }
 
@@ -358,7 +358,7 @@ static int ext4_fc_track_template(
 	spin_lock(&sbi->s_fc_lock);
 	if (list_empty(&EXT4_I(inode)->i_fc_list))
 		list_add_tail(&EXT4_I(inode)->i_fc_list,
-				(sbi->s_mount_state & EXT4_FC_COMMITTING) ?
+				(sbi->s_mount_flags & EXT4_MF_FC_COMMITTING) ?
 				&sbi->s_fc_q[FC_Q_STAGING] :
 				&sbi->s_fc_q[FC_Q_MAIN]);
 	spin_unlock(&sbi->s_fc_lock);
@@ -411,7 +411,7 @@ static int __track_dentry_update(struct inode *inode, void *arg, bool update)
 	node->fcd_name.len = dentry->d_name.len;
 
 	spin_lock(&sbi->s_fc_lock);
-	if (sbi->s_mount_state & EXT4_FC_COMMITTING)
+	if (sbi->s_mount_flags & EXT4_MF_FC_COMMITTING)
 		list_add_tail(&node->fcd_list,
 				&sbi->s_fc_dentry_q[FC_Q_STAGING]);
 	else
@@ -846,7 +846,7 @@ static int ext4_fc_submit_inode_data_all(journal_t *journal)
 	int ret = 0;
 
 	spin_lock(&sbi->s_fc_lock);
-	sbi->s_mount_state |= EXT4_FC_COMMITTING;
+	sbi->s_mount_flags |= EXT4_MF_FC_COMMITTING;
 	list_for_each(pos, &sbi->s_fc_q[FC_Q_MAIN]) {
 		ei = list_entry(pos, struct ext4_inode_info, i_fc_list);
 		ext4_set_inode_state(&ei->vfs_inode, EXT4_STATE_FC_COMMITTING);
@@ -964,7 +964,6 @@ static int ext4_fc_commit_dentry_updates(journal_t *journal, u32 *crc)
 			fc_dentry->fcd_parent, fc_dentry->fcd_ino,
 			fc_dentry->fcd_name.len,
 			fc_dentry->fcd_name.name, crc)) {
-			spin_lock(&sbi->s_fc_lock);
 			ret = -ENOSPC;
 			goto lock_and_exit;
 		}
@@ -1191,8 +1190,8 @@ static void ext4_fc_cleanup(journal_t *journal, int full)
 	list_splice_init(&sbi->s_fc_q[FC_Q_STAGING],
 				&sbi->s_fc_q[FC_Q_STAGING]);
 
-	sbi->s_mount_state &= ~EXT4_FC_COMMITTING;
-	sbi->s_mount_state &= ~EXT4_FC_INELIGIBLE;
+	sbi->s_mount_flags &= ~EXT4_MF_FC_COMMITTING;
+	sbi->s_mount_flags &= ~EXT4_MF_FC_INELIGIBLE;
 
 	if (full)
 		sbi->s_fc_bytes = 0;
@@ -1617,8 +1616,10 @@ static int ext4_fc_replay_add_range(struct super_block *sb,
 		if (ret == 0) {
 			/* Range is not mapped */
 			path = ext4_find_extent(inode, cur, NULL, 0);
-			if (!path)
-				continue;
+			if (IS_ERR(path)) {
+				iput(inode);
+				return 0;
+			}
 			memset(&newex, 0, sizeof(newex));
 			newex.ee_block = cpu_to_le32(cur);
 			ext4_ext_store_pblock(
@@ -2078,6 +2079,8 @@ static int ext4_fc_replay(journal_t *journal, struct buffer_head *bh,
 
 void ext4_fc_init(struct super_block *sb, journal_t *journal)
 {
+	int num_fc_blocks;
+
 	/*
 	 * We set replay callback even if fast commit disabled because we may
 	 * could still have fast commit blocks that need to be replayed even if
@@ -2087,7 +2090,15 @@ void ext4_fc_init(struct super_block *sb, journal_t *journal)
 	if (!test_opt2(sb, JOURNAL_FAST_COMMIT))
 		return;
 	journal->j_fc_cleanup_callback = ext4_fc_cleanup;
-	if (jbd2_fc_init(journal, EXT4_NUM_FC_BLKS)) {
+	if (!buffer_uptodate(journal->j_sb_buffer)
+		&& ext4_read_bh_lock(journal->j_sb_buffer, REQ_META | REQ_PRIO,
+					true)) {
+		ext4_msg(sb, KERN_ERR, "I/O error on journal");
+		return;
+	}
+	num_fc_blocks = be32_to_cpu(journal->j_superblock->s_num_fc_blks);
+	if (jbd2_fc_init(journal, num_fc_blocks ? num_fc_blocks :
+					EXT4_NUM_FC_BLKS)) {
 		pr_warn("Error while enabling fast commits, turning off.");
 		ext4_clear_feature_fast_commit(sb);
 	}
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 739dc8ed4d21..afb48a980c19 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1931,7 +1931,7 @@ static int __ext4_journalled_writepage(struct page *page,
 	}
 	if (ret == 0)
 		ret = err;
-	err = ext4_jbd2_inode_add_write(handle, inode, 0, len);
+	err = ext4_jbd2_inode_add_write(handle, inode, page_offset(page), len);
 	if (ret == 0)
 		ret = err;
 	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
@@ -3331,10 +3331,12 @@ static bool ext4_inode_datasync_dirty(struct inode *inode)
 
 	if (journal) {
 		if (jbd2_transaction_committed(journal,
-					EXT4_I(inode)->i_datasync_tid))
-			return true;
-		return atomic_read(&EXT4_SB(inode->i_sb)->s_fc_subtid) >=
-			EXT4_I(inode)->i_fc_committed_subtid;
+			EXT4_I(inode)->i_datasync_tid))
+			return false;
+		if (test_opt2(inode->i_sb, JOURNAL_FAST_COMMIT))
+			return atomic_read(&EXT4_SB(inode->i_sb)->s_fc_subtid) <
+				EXT4_I(inode)->i_fc_committed_subtid;
+		return true;
 	}
 
 	/* Any metadata buffers to write? */
@@ -6181,7 +6183,8 @@ retry_alloc:
 			if (ext4_walk_page_buffers(handle, page_buffers(page),
 					0, len, NULL, write_end_fn))
 				goto out_error;
-			if (ext4_jbd2_inode_add_write(handle, inode, 0, len))
+			if (ext4_jbd2_inode_add_write(handle, inode,
+						      page_offset(page), len))
 				goto out_error;
 			ext4_set_inode_state(inode, EXT4_STATE_JDATA);
 		} else {
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index b370c3c10073..6f622c69f941 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4771,8 +4771,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	INIT_LIST_HEAD(&sbi->s_fc_dentry_q[FC_Q_MAIN]);
 	INIT_LIST_HEAD(&sbi->s_fc_dentry_q[FC_Q_STAGING]);
 	sbi->s_fc_bytes = 0;
-	sbi->s_mount_state &= ~EXT4_FC_INELIGIBLE;
-	sbi->s_mount_state &= ~EXT4_FC_COMMITTING;
+	sbi->s_mount_flags &= ~EXT4_MF_FC_INELIGIBLE;
+	sbi->s_mount_flags &= ~EXT4_MF_FC_COMMITTING;
 	spin_lock_init(&sbi->s_fc_lock);
 	memset(&sbi->s_fc_stats, 0, sizeof(sbi->s_fc_stats));
 	sbi->s_fc_replay_state.fc_regions = NULL;
diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
index 5ff33d18996a..4e27fe6ed3ae 100644
--- a/fs/ext4/sysfs.c
+++ b/fs/ext4/sysfs.c
@@ -315,6 +315,7 @@ EXT4_ATTR_FEATURE(casefold);
 EXT4_ATTR_FEATURE(verity);
 #endif
 EXT4_ATTR_FEATURE(metadata_csum_seed);
+EXT4_ATTR_FEATURE(fast_commit);
 
 static struct attribute *ext4_feat_attrs[] = {
 	ATTR_LIST(lazy_itable_init),
@@ -331,6 +332,7 @@ static struct attribute *ext4_feat_attrs[] = {
 	ATTR_LIST(verity),
 #endif
 	ATTR_LIST(metadata_csum_seed),
+	ATTR_LIST(fast_commit),
 	NULL,
 };
 ATTRIBUTE_GROUPS(ext4_feat);
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index fb3d71ad6eea..1d5566af48ac 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -263,7 +263,10 @@ typedef struct journal_superblock_s
 /* 0x0050 */
 	__u8	s_checksum_type;	/* checksum type */
 	__u8	s_padding2[3];
-	__u32	s_padding[42];
+/* 0x0054 */
+	__be32	s_num_fc_blks;		/* Number of fast commit blocks */
+/* 0x0058 */
+	__u32	s_padding[41];
 	__be32	s_checksum;		/* crc32c(superblock) */
 
 /* 0x0100 */
@@ -1253,7 +1256,7 @@ struct journal_s
 	 */
 	void (*j_fc_cleanup_callback)(struct journal_s *journal, int);
 
-	/*
+	/**
 	 * @j_fc_replay_callback:
 	 *
 	 * File-system specific function that performs replay of a fast