staging: erofs: use common file type conversion

Deduplicate the EROFS file type conversion implementation and
remove EROFS_FT_* definitions since it's the same as defined
by POSIX, let's follow ext2 as Linus pointed out [1]
commit e108921894 ("ext2: use common file type conversion").

[1] https://lore.kernel.org/r/CAHk-=wiUs+b=iVKM3mVooXgVk7cmmC67KTmnAuL0cd_cMMVAKw@mail.gmail.com/

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Link: https://lore.kernel.org/r/20190816071142.8633-1-gaoxiang25@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/erofs/dir.c

@@ -8,17 +8,6 @@
  */
 #include "internal.h"
 
-static const unsigned char erofs_filetype_table[EROFS_FT_MAX] = {
-	[EROFS_FT_UNKNOWN]	= DT_UNKNOWN,
-	[EROFS_FT_REG_FILE]	= DT_REG,
-	[EROFS_FT_DIR]		= DT_DIR,
-	[EROFS_FT_CHRDEV]	= DT_CHR,
-	[EROFS_FT_BLKDEV]	= DT_BLK,
-	[EROFS_FT_FIFO]		= DT_FIFO,
-	[EROFS_FT_SOCK]		= DT_SOCK,
-	[EROFS_FT_SYMLINK]	= DT_LNK,
-};
-
 static void debug_one_dentry(unsigned char d_type, const char *de_name,
 			     unsigned int de_namelen)
 {
@@ -46,10 +35,7 @@ static int erofs_fill_dentries(struct inode *dir, struct dir_context *ctx,
 		unsigned int de_namelen;
 		unsigned char d_type;
 
-		if (de->file_type < EROFS_FT_MAX)
-			d_type = erofs_filetype_table[de->file_type];
-		else
-			d_type = DT_UNKNOWN;
+		d_type = fs_ftype_to_dtype(de->file_type);
 
 		nameoff = le16_to_cpu(de->nameoff);
 		de_name = (char *)dentry_blk + nameoff;

drivers/staging/erofs/erofs_fs.h

@@ -282,18 +282,11 @@ struct erofs_dirent {
 	__u8 reserved;  /* 11, reserved */
 } __packed;
 
-/* file types used in inode_info->flags */
-enum {
-	EROFS_FT_UNKNOWN,
-	EROFS_FT_REG_FILE,
-	EROFS_FT_DIR,
-	EROFS_FT_CHRDEV,
-	EROFS_FT_BLKDEV,
-	EROFS_FT_FIFO,
-	EROFS_FT_SOCK,
-	EROFS_FT_SYMLINK,
-	EROFS_FT_MAX
-};
+/*
+ * EROFS file types should match generic FT_* types and
+ * it seems no need to add BUILD_BUG_ONs since potential
+ * unmatchness will break other fses as well...
+ */
 
 #define EROFS_NAME_LEN      255
 

drivers/staging/erofs/namei.c

@@ -237,7 +237,7 @@ static struct dentry *erofs_lookup(struct inode *dir,
 	} else {
 		debugln("%s, %s (nid %llu) found, d_type %u", __func__,
 			dentry->d_name.name, nid, d_type);
-		inode = erofs_iget(dir->i_sb, nid, d_type == EROFS_FT_DIR);
+		inode = erofs_iget(dir->i_sb, nid, d_type == FT_DIR);
 	}
 	return d_splice_alias(inode, dentry);
 }