f2fs: align f2fs maximum name length to linux based filesystem

The maximum filename length supported in linux is 255 characters.
So let's follow that.
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

fs/f2fs/dir.c

@@ -189,6 +189,9 @@ struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir,
 	unsigned int max_depth;
 	unsigned int level;
 
+	if (namelen > F2FS_NAME_LEN)
+		return NULL;
+
 	if (npages == 0)
 		return NULL;
 

fs/f2fs/namei.c

@@ -197,7 +197,7 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
 	struct f2fs_dir_entry *de;
 	struct page *page;
 
-	if (dentry->d_name.len > F2FS_MAX_NAME_LEN)
+	if (dentry->d_name.len > F2FS_NAME_LEN)
 		return ERR_PTR(-ENAMETOOLONG);
 
 	de = f2fs_find_entry(dir, &dentry->d_name, &page);

fs/f2fs/super.c

@@ -180,7 +180,7 @@ static int f2fs_statfs(struct dentry *dentry, struct kstatfs *buf)
 	buf->f_files = sbi->total_node_count;
 	buf->f_ffree = sbi->total_node_count - valid_inode_count(sbi);
 
-	buf->f_namelen = F2FS_MAX_NAME_LEN;
+	buf->f_namelen = F2FS_NAME_LEN;
 	buf->f_fsid.val[0] = (u32)id;
 	buf->f_fsid.val[1] = (u32)(id >> 32);
 

include/linux/f2fs_fs.h

@@ -139,7 +139,7 @@ struct f2fs_extent {
 	__le32 len;		/* lengh of the extent */
 } __packed;
 
-#define F2FS_MAX_NAME_LEN	256
+#define F2FS_NAME_LEN		255
 #define ADDRS_PER_INODE         923	/* Address Pointers in an Inode */
 #define ADDRS_PER_BLOCK         1018	/* Address Pointers in a Direct Block */
 #define NIDS_PER_BLOCK          1018	/* Node IDs in an Indirect Block */
@@ -165,7 +165,8 @@ struct f2fs_inode {
 	__le32 i_flags;			/* file attributes */
 	__le32 i_pino;			/* parent inode number */
 	__le32 i_namelen;		/* file name length */
-	__u8 i_name[F2FS_MAX_NAME_LEN];	/* file name for SPOR */
+	__u8 i_name[F2FS_NAME_LEN];	/* file name for SPOR */
+	__u8 i_reserved2;		/* for backward compatibility */
 
 	struct f2fs_extent i_ext;	/* caching a largest extent */
 
@@ -362,10 +363,10 @@ struct f2fs_summary_block {
 typedef __le32	f2fs_hash_t;
 
 /* One directory entry slot covers 8bytes-long file name */
-#define F2FS_NAME_LEN		8
-#define F2FS_NAME_LEN_BITS	3
+#define F2FS_SLOT_LEN		8
+#define F2FS_SLOT_LEN_BITS	3
 
-#define GET_DENTRY_SLOTS(x)	((x + F2FS_NAME_LEN - 1) >> F2FS_NAME_LEN_BITS)
+#define GET_DENTRY_SLOTS(x)	((x + F2FS_SLOT_LEN - 1) >> F2FS_SLOT_LEN_BITS)
 
 /* the number of dentry in a block */
 #define NR_DENTRY_IN_BLOCK	214
@@ -377,10 +378,10 @@ typedef __le32	f2fs_hash_t;
 #define SIZE_OF_DENTRY_BITMAP	((NR_DENTRY_IN_BLOCK + BITS_PER_BYTE - 1) / \
 					BITS_PER_BYTE)
 #define SIZE_OF_RESERVED	(PAGE_SIZE - ((SIZE_OF_DIR_ENTRY + \
-				F2FS_NAME_LEN) * \
+				F2FS_SLOT_LEN) * \
 				NR_DENTRY_IN_BLOCK + SIZE_OF_DENTRY_BITMAP))
 
-/* One directory entry slot representing F2FS_NAME_LEN-sized file name */
+/* One directory entry slot representing F2FS_SLOT_LEN-sized file name */
 struct f2fs_dir_entry {
 	__le32 hash_code;	/* hash code of file name */
 	__le32 ino;		/* inode number */
@@ -394,7 +395,7 @@ struct f2fs_dentry_block {
 	__u8 dentry_bitmap[SIZE_OF_DENTRY_BITMAP];
 	__u8 reserved[SIZE_OF_RESERVED];
 	struct f2fs_dir_entry dentry[NR_DENTRY_IN_BLOCK];
-	__u8 filename[NR_DENTRY_IN_BLOCK][F2FS_NAME_LEN];
+	__u8 filename[NR_DENTRY_IN_BLOCK][F2FS_SLOT_LEN];
 } __packed;
 
 /* file types used in inode_info->flags */