Merge tag 'exfat-for-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat

Pull exfat update from Namjae Jeon:

 - simplify and remove some redundant directory entry code

 - optimize the size of exfat_entry_set_cache and its allocation policy

 - improve the performance for creating files and directories

* tag 'exfat-for-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat:
  exfat: reuse exfat_find_location() to simplify exfat_get_dentry_set()
  exfat: fix overflow in sector and cluster conversion
  exfat: remove i_size_write() from __exfat_truncate()
  exfat: remove argument 'size' from exfat_truncate()
  exfat: remove unnecessary arguments from exfat_find_dir_entry()
  exfat: remove unneeded codes from __exfat_rename()
  exfat: remove call ilog2() from exfat_readdir()
  exfat: replace magic numbers with Macros
  exfat: rename exfat_free_dentry_set() to exfat_put_dentry_set()
  exfat: move exfat_entry_set_cache from heap to stack
  exfat: support dynamic allocate bh for exfat_entry_set_cache
  exfat: reduce the size of exfat_entry_set_cache
  exfat: hint the empty entry which at the end of cluster chain
  exfat: simplify empty entry hint

5 files changed, 187 insertions, 145 deletions

diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c
index 0fc08fdcba73..1dfa67f307f1 100644
--- a/fs/exfat/dir.c
+++ b/fs/exfat/dir.c
@@ -33,10 +33,9 @@ static void exfat_get_uniname_from_ext_entry(struct super_block *sb,
 		struct exfat_chain *p_dir, int entry, unsigned short *uniname)
 {
 	int i;
-	struct exfat_entry_set_cache *es;
+	struct exfat_entry_set_cache es;
 
-	es = exfat_get_dentry_set(sb, p_dir, entry, ES_ALL_ENTRIES);
-	if (!es)
+	if (exfat_get_dentry_set(&es, sb, p_dir, entry, ES_ALL_ENTRIES))
 		return;
 
 	/*
@@ -45,8 +44,8 @@ static void exfat_get_uniname_from_ext_entry(struct super_block *sb,
 	 * Third entry  : first file-name entry
 	 * So, the index of first file-name dentry should start from 2.
 	 */
-	for (i = 2; i < es->num_entries; i++) {
-		struct exfat_dentry *ep = exfat_get_dentry_cached(es, i);
+	for (i = ES_IDX_FIRST_FILENAME; i < es.num_entries; i++) {
+		struct exfat_dentry *ep = exfat_get_dentry_cached(&es, i);
 
 		/* end of name entry */
 		if (exfat_get_entry_type(ep) != TYPE_EXTEND)
@@ -56,13 +55,13 @@ static void exfat_get_uniname_from_ext_entry(struct super_block *sb,
 		uniname += EXFAT_FILE_NAME_LEN;
 	}
 
-	exfat_free_dentry_set(es, false);
+	exfat_put_dentry_set(&es, false);
 }
 
 /* read a directory entry from the opened directory */
 static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_entry *dir_entry)
 {
-	int i, dentries_per_clu, dentries_per_clu_bits = 0, num_ext;
+	int i, dentries_per_clu, num_ext;
 	unsigned int type, clu_offset, max_dentries;
 	struct exfat_chain dir, clu;
 	struct exfat_uni_name uni_name;
@@ -84,11 +83,10 @@ static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_ent
 			EXFAT_B_TO_CLU(i_size_read(inode), sbi), ei->flags);
 
 	dentries_per_clu = sbi->dentries_per_clu;
-	dentries_per_clu_bits = ilog2(dentries_per_clu);
 	max_dentries = (unsigned int)min_t(u64, MAX_EXFAT_DENTRIES,
-					   (u64)sbi->num_clusters << dentries_per_clu_bits);
+				(u64)EXFAT_CLU_TO_DEN(sbi->num_clusters, sbi));
 
-	clu_offset = dentry >> dentries_per_clu_bits;
+	clu_offset = EXFAT_DEN_TO_CLU(dentry, sbi);
 	exfat_chain_dup(&clu, &dir);
 
 	if (clu.flags == ALLOC_NO_FAT_CHAIN) {
@@ -163,7 +161,7 @@ static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_ent
 			dir_entry->entry = dentry;
 			brelse(bh);
 
-			ei->hint_bmap.off = dentry >> dentries_per_clu_bits;
+			ei->hint_bmap.off = EXFAT_DEN_TO_CLU(dentry, sbi);
 			ei->hint_bmap.clu = clu.dir;
 
 			*cpos = EXFAT_DEN_TO_B(dentry + 1 + num_ext);
@@ -337,7 +335,7 @@ int exfat_calc_num_entries(struct exfat_uni_name *p_uniname)
 		return -EINVAL;
 
 	/* 1 file entry + 1 stream entry + name entries */
-	return ((len - 1) / EXFAT_FILE_NAME_LEN + 3);
+	return ES_ENTRY_NUM(len);
 }
 
 unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
@@ -592,18 +590,18 @@ void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es)
 	unsigned short chksum = 0;
 	struct exfat_dentry *ep;
 
-	for (i = 0; i < es->num_entries; i++) {
+	for (i = ES_IDX_FILE; i < es->num_entries; i++) {
 		ep = exfat_get_dentry_cached(es, i);
 		chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
 					     chksum_type);
 		chksum_type = CS_DEFAULT;
 	}
-	ep = exfat_get_dentry_cached(es, 0);
+	ep = exfat_get_dentry_cached(es, ES_IDX_FILE);
 	ep->dentry.file.checksum = cpu_to_le16(chksum);
 	es->modified = true;
 }
 
-int exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync)
+int exfat_put_dentry_set(struct exfat_entry_set_cache *es, int sync)
 {
 	int i, err = 0;
 
@@ -615,7 +613,10 @@ int exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync)
 			bforget(es->bh[i]);
 		else
 			brelse(es->bh[i]);
-	kfree(es);
+
+	if (IS_DYNAMIC_ES(es))
+		kfree(es->bh);
+
 	return err;
 }
 
@@ -812,14 +813,14 @@ struct exfat_dentry *exfat_get_dentry_cached(
  *   pointer of entry set on success,
  *   NULL on failure.
  */
-struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
-		struct exfat_chain *p_dir, int entry, unsigned int type)
+int exfat_get_dentry_set(struct exfat_entry_set_cache *es,
+		struct super_block *sb, struct exfat_chain *p_dir, int entry,
+		unsigned int type)
 {
 	int ret, i, num_bh;
-	unsigned int off, byte_offset, clu = 0;
+	unsigned int off;
 	sector_t sec;
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
-	struct exfat_entry_set_cache *es;
 	struct exfat_dentry *ep;
 	int num_entries;
 	enum exfat_validate_dentry_mode mode = ES_MODE_STARTED;
@@ -827,52 +828,51 @@ struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
 
 	if (p_dir->dir == DIR_DELETED) {
 		exfat_err(sb, "access to deleted dentry");
-		return NULL;
+		return -EIO;
 	}
 
-	byte_offset = EXFAT_DEN_TO_B(entry);
-	ret = exfat_walk_fat_chain(sb, p_dir, byte_offset, &clu);
+	ret = exfat_find_location(sb, p_dir, entry, &sec, &off);
 	if (ret)
-		return NULL;
+		return ret;
 
-	es = kzalloc(sizeof(*es), GFP_KERNEL);
-	if (!es)
-		return NULL;
+	memset(es, 0, sizeof(*es));
 	es->sb = sb;
 	es->modified = false;
-
-	/* byte offset in cluster */
-	byte_offset = EXFAT_CLU_OFFSET(byte_offset, sbi);
-
-	/* byte offset in sector */
-	off = EXFAT_BLK_OFFSET(byte_offset, sb);
 	es->start_off = off;
-
-	/* sector offset in cluster */
-	sec = EXFAT_B_TO_BLK(byte_offset, sb);
-	sec += exfat_cluster_to_sector(sbi, clu);
+	es->bh = es->__bh;
 
 	bh = sb_bread(sb, sec);
 	if (!bh)
-		goto free_es;
+		return -EIO;
 	es->bh[es->num_bh++] = bh;
 
-	ep = exfat_get_dentry_cached(es, 0);
+	ep = exfat_get_dentry_cached(es, ES_IDX_FILE);
 	if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
-		goto free_es;
+		goto put_es;
 
 	num_entries = type == ES_ALL_ENTRIES ?
 		ep->dentry.file.num_ext + 1 : type;
 	es->num_entries = num_entries;
 
 	num_bh = EXFAT_B_TO_BLK_ROUND_UP(off + num_entries * DENTRY_SIZE, sb);
+	if (num_bh > ARRAY_SIZE(es->__bh)) {
+		es->bh = kmalloc_array(num_bh, sizeof(*es->bh), GFP_KERNEL);
+		if (!es->bh) {
+			brelse(bh);
+			return -ENOMEM;
+		}
+		es->bh[0] = bh;
+	}
+
 	for (i = 1; i < num_bh; i++) {
 		/* get the next sector */
 		if (exfat_is_last_sector_in_cluster(sbi, sec)) {
+			unsigned int clu = exfat_sector_to_cluster(sbi, sec);
+
 			if (p_dir->flags == ALLOC_NO_FAT_CHAIN)
 				clu++;
 			else if (exfat_get_next_cluster(sb, &clu))
-				goto free_es;
+				goto put_es;
 			sec = exfat_cluster_to_sector(sbi, clu);
 		} else {
 			sec++;
@@ -880,21 +880,51 @@ struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
 
 		bh = sb_bread(sb, sec);
 		if (!bh)
-			goto free_es;
+			goto put_es;
 		es->bh[es->num_bh++] = bh;
 	}
 
 	/* validate cached dentries */
-	for (i = 1; i < num_entries; i++) {
+	for (i = ES_IDX_STREAM; i < num_entries; i++) {
 		ep = exfat_get_dentry_cached(es, i);
 		if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
-			goto free_es;
+			goto put_es;
 	}
-	return es;
+	return 0;
+
+put_es:
+	exfat_put_dentry_set(es, false);
+	return -EIO;
+}
 
-free_es:
-	exfat_free_dentry_set(es, false);
-	return NULL;
+static inline void exfat_reset_empty_hint(struct exfat_hint_femp *hint_femp)
+{
+	hint_femp->eidx = EXFAT_HINT_NONE;
+	hint_femp->count = 0;
+}
+
+static inline void exfat_set_empty_hint(struct exfat_inode_info *ei,
+		struct exfat_hint_femp *candi_empty, struct exfat_chain *clu,
+		int dentry, int num_entries, int entry_type)
+{
+	if (ei->hint_femp.eidx == EXFAT_HINT_NONE ||
+	    ei->hint_femp.eidx > dentry) {
+		int total_entries = EXFAT_B_TO_DEN(i_size_read(&ei->vfs_inode));
+
+		if (candi_empty->count == 0) {
+			candi_empty->cur = *clu;
+			candi_empty->eidx = dentry;
+		}
+
+		if (entry_type == TYPE_UNUSED)
+			candi_empty->count += total_entries - dentry;
+		else
+			candi_empty->count++;
+
+		if (candi_empty->count == num_entries ||
+		    candi_empty->count + candi_empty->eidx == total_entries)
+			ei->hint_femp = *candi_empty;
+	}
 }
 
 enum {
@@ -917,17 +947,21 @@ enum {
  */
 int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
 		struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
-		int num_entries, unsigned int type, struct exfat_hint *hint_opt)
+		struct exfat_hint *hint_opt)
 {
 	int i, rewind = 0, dentry = 0, end_eidx = 0, num_ext = 0, len;
 	int order, step, name_len = 0;
-	int dentries_per_clu, num_empty = 0;
+	int dentries_per_clu;
 	unsigned int entry_type;
 	unsigned short *uniname = NULL;
 	struct exfat_chain clu;
 	struct exfat_hint *hint_stat = &ei->hint_stat;
 	struct exfat_hint_femp candi_empty;
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	int num_entries = exfat_calc_num_entries(p_uniname);
+
+	if (num_entries < 0)
+		return num_entries;
 
 	dentries_per_clu = sbi->dentries_per_clu;
 
@@ -939,10 +973,13 @@ int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
 		end_eidx = dentry;
 	}
 
-	candi_empty.eidx = EXFAT_HINT_NONE;
+	exfat_reset_empty_hint(&ei->hint_femp);
+
 rewind:
 	order = 0;
 	step = DIRENT_STEP_FILE;
+	exfat_reset_empty_hint(&candi_empty);
+
 	while (clu.dir != EXFAT_EOF_CLUSTER) {
 		i = dentry & (dentries_per_clu - 1);
 		for (; i < dentries_per_clu; i++, dentry++) {
@@ -962,26 +999,9 @@ rewind:
 			    entry_type == TYPE_DELETED) {
 				step = DIRENT_STEP_FILE;
 
-				num_empty++;
-				if (candi_empty.eidx == EXFAT_HINT_NONE &&
-						num_empty == 1) {
-					exfat_chain_set(&candi_empty.cur,
-						clu.dir, clu.size, clu.flags);
-				}
-
-				if (candi_empty.eidx == EXFAT_HINT_NONE &&
-						num_empty >= num_entries) {
-					candi_empty.eidx =
-						dentry - (num_empty - 1);
-					WARN_ON(candi_empty.eidx < 0);
-					candi_empty.count = num_empty;
-
-					if (ei->hint_femp.eidx ==
-							EXFAT_HINT_NONE ||
-						candi_empty.eidx <=
-							 ei->hint_femp.eidx)
-						ei->hint_femp = candi_empty;
-				}
+				exfat_set_empty_hint(ei, &candi_empty, &clu,
+						dentry, num_entries,
+						entry_type);
 
 				brelse(bh);
 				if (entry_type == TYPE_UNUSED)
@@ -989,17 +1009,14 @@ rewind:
 				continue;
 			}
 
-			num_empty = 0;
-			candi_empty.eidx = EXFAT_HINT_NONE;
+			exfat_reset_empty_hint(&candi_empty);
 
 			if (entry_type == TYPE_FILE || entry_type == TYPE_DIR) {
 				step = DIRENT_STEP_FILE;
 				hint_opt->clu = clu.dir;
 				hint_opt->eidx = i;
-				if (type == TYPE_ALL || type == entry_type) {
-					num_ext = ep->dentry.file.num_ext;
-					step = DIRENT_STEP_STRM;
-				}
+				num_ext = ep->dentry.file.num_ext;
+				step = DIRENT_STEP_STRM;
 				brelse(bh);
 				continue;
 			}
@@ -1090,12 +1107,19 @@ not_found:
 		rewind = 1;
 		dentry = 0;
 		clu.dir = p_dir->dir;
-		/* reset empty hint */
-		num_empty = 0;
-		candi_empty.eidx = EXFAT_HINT_NONE;
 		goto rewind;
 	}
 
+	/*
+	 * set the EXFAT_EOF_CLUSTER flag to avoid search
+	 * from the beginning again when allocated a new cluster
+	 */
+	if (ei->hint_femp.eidx == EXFAT_HINT_NONE) {
+		ei->hint_femp.cur.dir = EXFAT_EOF_CLUSTER;
+		ei->hint_femp.eidx = p_dir->size * dentries_per_clu;
+		ei->hint_femp.count = 0;
+	}
+
 	/* initialized hint_stat */
 	hint_stat->clu = p_dir->dir;
 	hint_stat->eidx = 0;
diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h
index a8f8eee4937c..bc6d21d7c5ad 100644
--- a/fs/exfat/exfat_fs.h
+++ b/fs/exfat/exfat_fs.h
@@ -9,6 +9,7 @@
 #include <linux/fs.h>
 #include <linux/ratelimit.h>
 #include <linux/nls.h>
+#include <linux/blkdev.h>
 
 #define EXFAT_ROOT_INO		1
 
@@ -41,6 +42,14 @@ enum {
 #define ES_2_ENTRIES		2
 #define ES_ALL_ENTRIES		0
 
+#define ES_IDX_FILE		0
+#define ES_IDX_STREAM		1
+#define ES_IDX_FIRST_FILENAME	2
+#define EXFAT_FILENAME_ENTRY_NUM(name_len) \
+	DIV_ROUND_UP(name_len, EXFAT_FILE_NAME_LEN)
+#define ES_IDX_LAST_FILENAME(name_len)	\
+	(ES_IDX_FIRST_FILENAME + EXFAT_FILENAME_ENTRY_NUM(name_len) - 1)
+
 #define DIR_DELETED		0xFFFF0321
 
 /* type values */
@@ -62,15 +71,11 @@ enum {
 #define TYPE_PADDING		0x0402
 #define TYPE_ACLTAB		0x0403
 #define TYPE_BENIGN_SEC		0x0800
-#define TYPE_ALL		0x0FFF
 
 #define MAX_CHARSET_SIZE	6 /* max size of multi-byte character */
 #define MAX_NAME_LENGTH		255 /* max len of file name excluding NULL */
 #define MAX_VFSNAME_BUF_SIZE	((MAX_NAME_LENGTH + 1) * MAX_CHARSET_SIZE)
 
-/* Enough size to hold 256 dentry (even 512 Byte sector) */
-#define DIR_CACHE_SIZE		(256*sizeof(struct exfat_dentry)/512+1)
-
 #define EXFAT_HINT_NONE		-1
 #define EXFAT_MIN_SUBDIR	2
 
@@ -95,12 +100,18 @@ enum {
 /*
  * helpers for block size to dentry size conversion.
  */
-#define EXFAT_B_TO_DEN_IDX(b, sbi)	\
-	((b) << ((sbi)->cluster_size_bits - DENTRY_SIZE_BITS))
 #define EXFAT_B_TO_DEN(b)		((b) >> DENTRY_SIZE_BITS)
 #define EXFAT_DEN_TO_B(b)		((b) << DENTRY_SIZE_BITS)
 
 /*
+ * helpers for cluster size to dentry size conversion.
+ */
+#define EXFAT_CLU_TO_DEN(clu, sbi)	\
+	((clu) << ((sbi)->cluster_size_bits - DENTRY_SIZE_BITS))
+#define EXFAT_DEN_TO_CLU(dentry, sbi)	\
+	((dentry) >> ((sbi)->cluster_size_bits - DENTRY_SIZE_BITS))
+
+/*
  * helpers for fat entry.
  */
 #define FAT_ENT_SIZE (4)
@@ -125,6 +136,17 @@ enum {
 #define BITS_PER_BYTE_MASK	0x7
 #define IGNORED_BITS_REMAINED(clu, clu_base) ((1 << ((clu) - (clu_base))) - 1)
 
+#define ES_ENTRY_NUM(name_len)	(ES_IDX_LAST_FILENAME(name_len) + 1)
+/* 19 entries = 1 file entry + 1 stream entry + 17 filename entries */
+#define ES_MAX_ENTRY_NUM	ES_ENTRY_NUM(MAX_NAME_LENGTH)
+
+/*
+ * 19 entries x 32 bytes/entry = 608 bytes.
+ * The 608 bytes are in 3 sectors at most (even 512 Byte sector).
+ */
+#define DIR_CACHE_SIZE		\
+	(DIV_ROUND_UP(EXFAT_DEN_TO_B(ES_MAX_ENTRY_NUM), SECTOR_SIZE) + 1)
+
 struct exfat_dentry_namebuf {
 	char *lfn;
 	int lfnbuf_len; /* usually MAX_UNINAME_BUF_SIZE */
@@ -166,13 +188,16 @@ struct exfat_hint {
 
 struct exfat_entry_set_cache {
 	struct super_block *sb;
-	bool modified;
 	unsigned int start_off;
 	int num_bh;
-	struct buffer_head *bh[DIR_CACHE_SIZE];
+	struct buffer_head *__bh[DIR_CACHE_SIZE];
+	struct buffer_head **bh;
 	unsigned int num_entries;
+	bool modified;
 };
 
+#define IS_DYNAMIC_ES(es)	((es)->__bh != (es)->bh)
+
 struct exfat_dir_entry {
 	struct exfat_chain dir;
 	int entry;
@@ -375,7 +400,7 @@ static inline sector_t exfat_cluster_to_sector(struct exfat_sb_info *sbi,
 		sbi->data_start_sector;
 }
 
-static inline int exfat_sector_to_cluster(struct exfat_sb_info *sbi,
+static inline unsigned int exfat_sector_to_cluster(struct exfat_sb_info *sbi,
 		sector_t sec)
 {
 	return ((sec - sbi->data_start_sector) >> sbi->sect_per_clus_bits) +
@@ -423,8 +448,8 @@ int exfat_trim_fs(struct inode *inode, struct fstrim_range *range);
 
 /* file.c */
 extern const struct file_operations exfat_file_operations;
-int __exfat_truncate(struct inode *inode, loff_t new_size);
-void exfat_truncate(struct inode *inode, loff_t size);
+int __exfat_truncate(struct inode *inode);
+void exfat_truncate(struct inode *inode);
 int exfat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 		  struct iattr *attr);
 int exfat_getattr(struct user_namespace *mnt_userns, const struct path *path,
@@ -464,15 +489,16 @@ void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es);
 int exfat_calc_num_entries(struct exfat_uni_name *p_uniname);
 int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
 		struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
-		int num_entries, unsigned int type, struct exfat_hint *hint_opt);
+		struct exfat_hint *hint_opt);
 int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu);
 struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
 		struct exfat_chain *p_dir, int entry, struct buffer_head **bh);
 struct exfat_dentry *exfat_get_dentry_cached(struct exfat_entry_set_cache *es,
 		int num);
-struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
-		struct exfat_chain *p_dir, int entry, unsigned int type);
-int exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync);
+int exfat_get_dentry_set(struct exfat_entry_set_cache *es,
+		struct super_block *sb, struct exfat_chain *p_dir, int entry,
+		unsigned int type);
+int exfat_put_dentry_set(struct exfat_entry_set_cache *es, int sync);
 int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir);
 
 /* inode.c */
diff --git a/fs/exfat/file.c b/fs/exfat/file.c
index 4e0793f35e8f..f5b29072775d 100644
--- a/fs/exfat/file.c
+++ b/fs/exfat/file.c
@@ -93,7 +93,7 @@ static int exfat_sanitize_mode(const struct exfat_sb_info *sbi,
 }
 
 /* resize the file length */
-int __exfat_truncate(struct inode *inode, loff_t new_size)
+int __exfat_truncate(struct inode *inode)
 {
 	unsigned int num_clusters_new, num_clusters_phys;
 	unsigned int last_clu = EXFAT_FREE_CLUSTER;
@@ -113,7 +113,7 @@ int __exfat_truncate(struct inode *inode, loff_t new_size)
 
 	exfat_chain_set(&clu, ei->start_clu, num_clusters_phys, ei->flags);
 
-	if (new_size > 0) {
+	if (i_size_read(inode) > 0) {
 		/*
 		 * Truncate FAT chain num_clusters after the first cluster
 		 * num_clusters = min(new, phys);
@@ -143,8 +143,6 @@ int __exfat_truncate(struct inode *inode, loff_t new_size)
 		ei->start_clu = EXFAT_EOF_CLUSTER;
 	}
 
-	i_size_write(inode, new_size);
-
 	if (ei->type == TYPE_FILE)
 		ei->attr |= ATTR_ARCHIVE;
 
@@ -189,7 +187,7 @@ int __exfat_truncate(struct inode *inode, loff_t new_size)
 	return 0;
 }
 
-void exfat_truncate(struct inode *inode, loff_t size)
+void exfat_truncate(struct inode *inode)
 {
 	struct super_block *sb = inode->i_sb;
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
@@ -207,7 +205,7 @@ void exfat_truncate(struct inode *inode, loff_t size)
 		goto write_size;
 	}
 
-	err = __exfat_truncate(inode, i_size_read(inode));
+	err = __exfat_truncate(inode);
 	if (err)
 		goto write_size;
 
@@ -310,7 +308,7 @@ int exfat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 		 * __exfat_write_inode() is called from exfat_truncate(), inode
 		 * is already written by it, so mark_inode_dirty() is unneeded.
 		 */
-		exfat_truncate(inode, attr->ia_size);
+		exfat_truncate(inode);
 		up_write(&EXFAT_I(inode)->truncate_lock);
 	} else
 		mark_inode_dirty(inode);
diff --git a/fs/exfat/inode.c b/fs/exfat/inode.c
index eac95bcd9a8a..5b644cb057fa 100644
--- a/fs/exfat/inode.c
+++ b/fs/exfat/inode.c
@@ -21,7 +21,7 @@ int __exfat_write_inode(struct inode *inode, int sync)
 {
 	unsigned long long on_disk_size;
 	struct exfat_dentry *ep, *ep2;
-	struct exfat_entry_set_cache *es = NULL;
+	struct exfat_entry_set_cache es;
 	struct super_block *sb = inode->i_sb;
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
 	struct exfat_inode_info *ei = EXFAT_I(inode);
@@ -42,11 +42,10 @@ int __exfat_write_inode(struct inode *inode, int sync)
 	exfat_set_volume_dirty(sb);
 
 	/* get the directory entry of given file or directory */
-	es = exfat_get_dentry_set(sb, &(ei->dir), ei->entry, ES_ALL_ENTRIES);
-	if (!es)
+	if (exfat_get_dentry_set(&es, sb, &(ei->dir), ei->entry, ES_ALL_ENTRIES))
 		return -EIO;
-	ep = exfat_get_dentry_cached(es, 0);
-	ep2 = exfat_get_dentry_cached(es, 1);
+	ep = exfat_get_dentry_cached(&es, ES_IDX_FILE);
+	ep2 = exfat_get_dentry_cached(&es, ES_IDX_STREAM);
 
 	ep->dentry.file.attr = cpu_to_le16(exfat_make_attr(inode));
 
@@ -83,8 +82,8 @@ int __exfat_write_inode(struct inode *inode, int sync)
 		ep2->dentry.stream.start_clu = EXFAT_FREE_CLUSTER;
 	}
 
-	exfat_update_dir_chksum_with_entry_set(es);
-	return exfat_free_dentry_set(es, sync);
+	exfat_update_dir_chksum_with_entry_set(&es);
+	return exfat_put_dentry_set(&es, sync);
 }
 
 int exfat_write_inode(struct inode *inode, struct writeback_control *wbc)
@@ -358,7 +357,7 @@ static void exfat_write_failed(struct address_space *mapping, loff_t to)
 	if (to > i_size_read(inode)) {
 		truncate_pagecache(inode, i_size_read(inode));
 		inode->i_mtime = inode->i_ctime = current_time(inode);
-		exfat_truncate(inode, EXFAT_I(inode)->i_size_aligned);
+		exfat_truncate(inode);
 	}
 }
 
@@ -622,7 +621,7 @@ void exfat_evict_inode(struct inode *inode)
 	if (!inode->i_nlink) {
 		i_size_write(inode, 0);
 		mutex_lock(&EXFAT_SB(inode->i_sb)->s_lock);
-		__exfat_truncate(inode, 0);
+		__exfat_truncate(inode);
 		mutex_unlock(&EXFAT_SB(inode->i_sb)->s_lock);
 	}
 
diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c
index b617bebc3d0f..5f995eba5dbb 100644
--- a/fs/exfat/namei.c
+++ b/fs/exfat/namei.c
@@ -224,11 +224,18 @@ static int exfat_search_empty_slot(struct super_block *sb,
 
 	if (hint_femp->eidx != EXFAT_HINT_NONE) {
 		dentry = hint_femp->eidx;
-		if (num_entries <= hint_femp->count) {
-			hint_femp->eidx = EXFAT_HINT_NONE;
-			return dentry;
-		}
 
+		/*
+		 * If hint_femp->count is enough, it is needed to check if
+		 * there are actual empty entries.
+		 * Otherwise, and if "dentry + hint_famp->count" is also equal
+		 * to "p_dir->size * dentries_per_clu", it means ENOSPC.
+		 */
+		if (dentry + hint_femp->count == p_dir->size * dentries_per_clu &&
+		    num_entries > hint_femp->count)
+			return -ENOSPC;
+
+		hint_femp->eidx = EXFAT_HINT_NONE;
 		exfat_chain_dup(&clu, &hint_femp->cur);
 	} else {
 		exfat_chain_dup(&clu, p_dir);
@@ -293,6 +300,12 @@ static int exfat_search_empty_slot(struct super_block *sb,
 		}
 	}
 
+	hint_femp->eidx = p_dir->size * dentries_per_clu - num_empty;
+	hint_femp->count = num_empty;
+	if (num_empty == 0)
+		exfat_chain_set(&hint_femp->cur, EXFAT_EOF_CLUSTER, 0,
+				clu.flags);
+
 	return -ENOSPC;
 }
 
@@ -369,15 +382,11 @@ static int exfat_find_empty_entry(struct inode *inode,
 			if (exfat_ent_set(sb, last_clu, clu.dir))
 				return -EIO;
 
-		if (hint_femp.eidx == EXFAT_HINT_NONE) {
-			/* the special case that new dentry
-			 * should be allocated from the start of new cluster
-			 */
-			hint_femp.eidx = EXFAT_B_TO_DEN_IDX(p_dir->size, sbi);
-			hint_femp.count = sbi->dentries_per_clu;
-
+		if (hint_femp.cur.dir == EXFAT_EOF_CLUSTER)
 			exfat_chain_set(&hint_femp.cur, clu.dir, 0, clu.flags);
-		}
+
+		hint_femp.count += sbi->dentries_per_clu;
+
 		hint_femp.cur.size++;
 		p_dir->size++;
 		size = EXFAT_CLU_TO_B(p_dir->size, sbi);
@@ -588,14 +597,14 @@ unlock:
 static int exfat_find(struct inode *dir, struct qstr *qname,
 		struct exfat_dir_entry *info)
 {
-	int ret, dentry, num_entries, count;
+	int ret, dentry, count;
 	struct exfat_chain cdir;
 	struct exfat_uni_name uni_name;
 	struct super_block *sb = dir->i_sb;
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
 	struct exfat_inode_info *ei = EXFAT_I(dir);
 	struct exfat_dentry *ep, *ep2;
-	struct exfat_entry_set_cache *es;
+	struct exfat_entry_set_cache es;
 	/* for optimized dir & entry to prevent long traverse of cluster chain */
 	struct exfat_hint hint_opt;
 
@@ -607,10 +616,6 @@ static int exfat_find(struct inode *dir, struct qstr *qname,
 	if (ret)
 		return ret;
 
-	num_entries = exfat_calc_num_entries(&uni_name);
-	if (num_entries < 0)
-		return num_entries;
-
 	/* check the validation of hint_stat and initialize it if required */
 	if (ei->version != (inode_peek_iversion_raw(dir) & 0xffffffff)) {
 		ei->hint_stat.clu = cdir.dir;
@@ -620,9 +625,7 @@ static int exfat_find(struct inode *dir, struct qstr *qname,
 	}
 
 	/* search the file name for directories */
-	dentry = exfat_find_dir_entry(sb, ei, &cdir, &uni_name,
-			num_entries, TYPE_ALL, &hint_opt);
-
+	dentry = exfat_find_dir_entry(sb, ei, &cdir, &uni_name, &hint_opt);
 	if (dentry < 0)
 		return dentry; /* -error value */
 
@@ -635,11 +638,10 @@ static int exfat_find(struct inode *dir, struct qstr *qname,
 	if (cdir.flags & ALLOC_NO_FAT_CHAIN)
 		cdir.size -= dentry / sbi->dentries_per_clu;
 	dentry = hint_opt.eidx;
-	es = exfat_get_dentry_set(sb, &cdir, dentry, ES_2_ENTRIES);
-	if (!es)
+	if (exfat_get_dentry_set(&es, sb, &cdir, dentry, ES_2_ENTRIES))
 		return -EIO;
-	ep = exfat_get_dentry_cached(es, 0);
-	ep2 = exfat_get_dentry_cached(es, 1);
+	ep = exfat_get_dentry_cached(&es, ES_IDX_FILE);
+	ep2 = exfat_get_dentry_cached(&es, ES_IDX_STREAM);
 
 	info->type = exfat_get_entry_type(ep);
 	info->attr = le16_to_cpu(ep->dentry.file.attr);
@@ -668,7 +670,7 @@ static int exfat_find(struct inode *dir, struct qstr *qname,
 			     ep->dentry.file.access_time,
 			     ep->dentry.file.access_date,
 			     0);
-	exfat_free_dentry_set(es, false);
+	exfat_put_dentry_set(&es, false);
 
 	if (ei->start_clu == EXFAT_FREE_CLUSTER) {
 		exfat_fs_error(sb,
@@ -1167,7 +1169,7 @@ static int __exfat_rename(struct inode *old_parent_inode,
 	struct exfat_inode_info *new_ei = NULL;
 	unsigned int new_entry_type = TYPE_UNUSED;
 	int new_entry = 0;
-	struct buffer_head *old_bh, *new_bh = NULL;
+	struct buffer_head *new_bh = NULL;
 
 	/* check the validity of pointer parameters */
 	if (new_path == NULL || strlen(new_path) == 0)
@@ -1183,13 +1185,6 @@ static int __exfat_rename(struct inode *old_parent_inode,
 		EXFAT_I(old_parent_inode)->flags);
 	dentry = ei->entry;
 
-	ep = exfat_get_dentry(sb, &olddir, dentry, &old_bh);
-	if (!ep) {
-		ret = -EIO;
-		goto out;
-	}
-	brelse(old_bh);
-
 	/* check whether new dir is existing directory and empty */
 	if (new_inode) {
 		ret = -EIO;