fs/ntfs3: Simplify initialization of $AttrDef and $UpCase

Replaced the two loops reading $AttrDef and $UpCase with
the inode_read_data() function.
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

fs/ntfs3/inode.c

@@ -1097,6 +1097,34 @@ int ntfs_flush_inodes(struct super_block *sb, struct inode *i1,
 	return ret;
 }
 
+/*
+ * Helper function to read file.
+ */
+int inode_read_data(struct inode *inode, void *data, size_t bytes)
+{
+	pgoff_t idx;
+	struct address_space *mapping = inode->i_mapping;
+
+	for (idx = 0; bytes; idx++) {
+		size_t op = bytes > PAGE_SIZE ? PAGE_SIZE : bytes;
+		struct page *page = read_mapping_page(mapping, idx, NULL);
+		void *kaddr;
+
+		if (IS_ERR(page))
+			return PTR_ERR(page);
+
+		kaddr = kmap_atomic(page);
+		memcpy(data, kaddr, op);
+		kunmap_atomic(kaddr);
+
+		put_page(page);
+
+		bytes -= op;
+		data = Add2Ptr(data, PAGE_SIZE);
+	}
+	return 0;
+}
+
 /*
  * ntfs_reparse_bytes
  *

fs/ntfs3/ntfs_fs.h

@@ -716,6 +716,7 @@ int ntfs3_write_inode(struct inode *inode, struct writeback_control *wbc);
 int ntfs_sync_inode(struct inode *inode);
 int ntfs_flush_inodes(struct super_block *sb, struct inode *i1,
 		      struct inode *i2);
+int inode_read_data(struct inode *inode, void *data, size_t bytes);
 int ntfs_create_inode(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *dentry, const struct cpu_str *uni,
 		      umode_t mode, dev_t dev, const char *symname, u32 size,
@@ -909,22 +910,6 @@ static inline bool ntfs_is_meta_file(struct ntfs_sb_info *sbi, CLST rno)
 	       rno == sbi->usn_jrnl_no;
 }
 
-static inline void ntfs_unmap_page(struct page *page)
-{
-	kunmap(page);
-	put_page(page);
-}
-
-static inline struct page *ntfs_map_page(struct address_space *mapping,
-					 unsigned long index)
-{
-	struct page *page = read_mapping_page(mapping, index, NULL);
-
-	if (!IS_ERR(page))
-		kmap(page);
-	return page;
-}
-
 static inline size_t wnd_zone_bit(const struct wnd_bitmap *wnd)
 {
 	return wnd->zone_bit;

fs/ntfs3/super.c

@@ -1163,7 +1163,7 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
 	CLST vcn, lcn, len;
 	struct ATTRIB *attr;
 	const struct VOLUME_INFO *info;
-	u32 idx, done, bytes;
+	u32 done, bytes;
 	struct ATTR_DEF_ENTRY *t;
 	u16 *shared;
 	struct MFT_REF ref;
@@ -1435,31 +1435,22 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
 		goto put_inode_out;
 	}
 
-	for (done = idx = 0; done < bytes; done += PAGE_SIZE, idx++) {
-		unsigned long tail = bytes - done;
-		struct page *page = ntfs_map_page(inode->i_mapping, idx);
-
-		if (IS_ERR(page)) {
-			err = PTR_ERR(page);
+	/* Read the entire file. */
+	err = inode_read_data(inode, sbi->def_table, bytes);
+	if (err) {
 		ntfs_err(sb, "Failed to read $AttrDef (%d).", err);
 		goto put_inode_out;
 	}
-		memcpy(Add2Ptr(t, done), page_address(page),
-		       min(PAGE_SIZE, tail));
-		ntfs_unmap_page(page);
 
-		if (!idx && ATTR_STD != t->type) {
+	if (ATTR_STD != t->type) {
 		ntfs_err(sb, "$AttrDef is corrupted.");
 		err = -EINVAL;
 		goto put_inode_out;
 	}
-	}
 
 	t += 1;
 	sbi->def_entries = 1;
 	done = sizeof(struct ATTR_DEF_ENTRY);
-	sbi->reparse.max_size = MAXIMUM_REPARSE_DATA_BUFFER_SIZE;
-	sbi->ea_max_size = 0x10000; /* default formatter value */
 
 	while (done + sizeof(struct ATTR_DEF_ENTRY) <= bytes) {
 		u32 t32 = le32_to_cpu(t->type);
@@ -1495,27 +1486,22 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
 		goto put_inode_out;
 	}
 
-	for (idx = 0; idx < (0x10000 * sizeof(short) >> PAGE_SHIFT); idx++) {
-		const __le16 *src;
-		u16 *dst = Add2Ptr(sbi->upcase, idx << PAGE_SHIFT);
-		struct page *page = ntfs_map_page(inode->i_mapping, idx);
-
-		if (IS_ERR(page)) {
-			err = PTR_ERR(page);
+	/* Read the entire file. */
+	err = inode_read_data(inode, sbi->upcase, 0x10000 * sizeof(short));
+	if (err) {
 		ntfs_err(sb, "Failed to read $UpCase (%d).", err);
 		goto put_inode_out;
 	}
 
-		src = page_address(page);
-
 #ifdef __BIG_ENDIAN
-		for (i = 0; i < PAGE_SIZE / sizeof(u16); i++)
+	{
+		const __le16 *src = sbi->upcase;
+		u16 *dst = sbi->upcase;
+
+		for (i = 0; i < 0x10000; i++)
 			*dst++ = le16_to_cpu(*src++);
-#else
-		memcpy(dst, src, PAGE_SIZE);
-#endif
-		ntfs_unmap_page(page);
 	}
+#endif
 
 	shared = ntfs_set_shared(sbi->upcase, 0x10000 * sizeof(short));
 	if (shared && sbi->upcase != shared) {