diff -drupN a/fs/fat/file.c b/fs/fat/file.c
--- a/fs/fat/file.c	2018-08-06 17:23:04.000000000 +0300
+++ b/fs/fat/file.c	2022-06-12 05:28:14.000000000 +0300
@@ -17,6 +17,10 @@
 #include <linux/falloc.h>
 #include "fat.h"
 
+#ifdef CONFIG_PRELLOCATE_FLAG
+static DEFINE_MUTEX (i_mutex);
+#endif
+
 static long fat_fallocate(struct file *file, int mode,
 			  loff_t offset, loff_t len);
 
@@ -121,6 +125,37 @@ static int fat_ioctl_get_volume_id(struc
 	return put_user(sbi->vol_id, user_attr);
 }
 
+static int fat_ioctl_fitrim(struct inode *inode, unsigned long arg)
+{
+	struct super_block *sb = inode->i_sb;
+	struct fstrim_range __user *user_range;
+	struct fstrim_range range;
+	struct request_queue *q = bdev_get_queue(sb->s_bdev);
+	int err;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (!blk_queue_discard(q))
+		return -EOPNOTSUPP;
+
+	user_range = (struct fstrim_range __user *)arg;
+	if (copy_from_user(&range, user_range, sizeof(range)))
+		return -EFAULT;
+
+	range.minlen = max_t(unsigned int, range.minlen,
+			     q->limits.discard_granularity);
+
+	err = fat_trim_fs(inode, &range);
+	if (err < 0)
+		return err;
+
+	if (copy_to_user(user_range, &range, sizeof(range)))
+		return -EFAULT;
+
+	return 0;
+}
+
 long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	struct inode *inode = file_inode(filp);
@@ -133,6 +168,8 @@ long fat_generic_ioctl(struct file *filp
 		return fat_ioctl_set_attributes(filp, user_attr);
 	case FAT_IOCTL_GET_VOLUME_ID:
 		return fat_ioctl_get_volume_id(inode, user_attr);
+	case FITRIM:
+		return fat_ioctl_fitrim(inode, arg);
 	default:
 		return -ENOTTY;	/* Inappropriate ioctl for device */
 	}
@@ -168,6 +205,17 @@ int fat_file_fsync(struct file *filp, lo
 	return res ? res : err;
 }
 
+#ifdef CONFIG_OPTIMIZE_METADATA_REFRESH
+int fat_file_flush(struct file *file, fl_owner_t id)
+{
+	struct address_space *mapping = file->f_mapping;
+	struct inode *inode = mapping->host;
+
+	inode->i_sb->s_op->write_inode(inode, NULL);
+
+	return 0;
+}
+#endif
 
 const struct file_operations fat_file_operations = {
 	.llseek		= generic_file_llseek,
@@ -182,6 +230,9 @@ const struct file_operations fat_file_op
 	.fsync		= fat_file_fsync,
 	.splice_read	= generic_file_splice_read,
 	.fallocate	= fat_fallocate,
+#ifdef CONFIG_OPTIMIZE_METADATA_REFRESH
+	.flush		= fat_file_flush,
+#endif
 };
 
 static int fat_cont_expand(struct inode *inode, loff_t size)
@@ -246,7 +297,17 @@ static long fat_fallocate(struct file *f
 	if (!S_ISREG(inode->i_mode))
 		return -EOPNOTSUPP;
 
+#ifdef CONFIG_PRELLOCATE_FLAG
+	if (check_prealloc(inode)) {
+		fat_msg(sb, KERN_ERR, "Repeatedly called fat_fallocate");
+		return -EOPNOTSUPP;
+	}
+#endif
+
 	inode_lock(inode);
+#ifdef CONFIG_PRELLOCATE_FLAG
+	mutex_lock(&i_mutex);
+#endif
 	if (mode & FALLOC_FL_KEEP_SIZE) {
 		ondisksize = inode->i_blocks << 9;
 		if ((offset + len) <= ondisksize)
@@ -271,7 +332,13 @@ static long fat_fallocate(struct file *f
 		err = fat_cont_expand(inode, (offset + len));
 	}
 
+#ifdef CONFIG_PRELLOCATE_FLAG
+	mark_prealloc(inode);
+#endif
 error:
+#ifdef CONFIG_PRELLOCATE_FLAG
+	mutex_unlock(&i_mutex);
+#endif
 	inode_unlock(inode);
 	return err;
 }
@@ -290,14 +357,19 @@ static int fat_free(struct inode *inode,
 	wait = IS_DIRSYNC(inode);
 	i_start = free_start = MSDOS_I(inode)->i_start;
 	i_logstart = MSDOS_I(inode)->i_logstart;
-
 	/* First, we write the new file size. */
+#ifdef CONFIG_TRUNCATE_NOMEM_RECLAIM
+	if (!skip && (inode->i_nlink == 0 || !check_prealloc(inode))) {
+#else
 	if (!skip) {
+#endif
 		MSDOS_I(inode)->i_start = 0;
 		MSDOS_I(inode)->i_logstart = 0;
 	}
+
 	MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
 	inode->i_ctime = inode->i_mtime = current_time(inode);
+
 	if (wait) {
 		err = fat_sync_inode(inode);
 		if (err) {
@@ -309,7 +381,11 @@ static int fat_free(struct inode *inode,
 		mark_inode_dirty(inode);
 
 	/* Write a new EOF, and get the remaining cluster chain for freeing. */
+#ifdef CONFIG_TRUNCATE_NOMEM_RECLAIM
+	if (skip && !check_prealloc(inode)) {
+#else
 	if (skip) {
+#endif
 		struct fat_entry fatent;
 		int ret, fclus, dclus;
 
@@ -340,8 +416,17 @@ static int fat_free(struct inode *inode,
 
 		free_start = ret;
 	}
-	inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9);
 
+#ifdef CONFIG_TRUNCATE_NOMEM_RECLAIM
+	if (check_prealloc(inode) && inode->i_nlink) {
+#ifdef CONFIG_TRUNCATE_NOMEM_RECLAIM_DISCARD
+		fat_discard_clusters(inode, free_start);
+#endif
+		return 0;
+	}
+#endif
+
+	inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9);
 	/* Freeing the remained cluster chain */
 	return fat_free_clusters(inode, free_start);
 }
@@ -468,10 +553,22 @@ int fat_setattr(struct dentry *dentry, s
 		inode_dio_wait(inode);
 
 		if (attr->ia_size > inode->i_size) {
+#ifdef CONFIG_TRUNCATE_NOMEM_RECLAIM
+			if (!check_prealloc(inode)) {
+				error = fat_cont_expand(inode, attr->ia_size);
+				if (error || attr->ia_valid == ATTR_SIZE)
+					goto out;
+				attr->ia_valid &= ~ATTR_SIZE;
+			} else {
+				pr_err("FAT ERR: (%s) incorrectly call ftruncate", __func__);
+				return -EOPNOTSUPP;
+			}
+#else
 			error = fat_cont_expand(inode, attr->ia_size);
 			if (error || attr->ia_valid == ATTR_SIZE)
 				goto out;
 			attr->ia_valid &= ~ATTR_SIZE;
+#endif
 		}
 	}