ext4: enable large folio for regular file

Besides fsverity, fscrypt, and the data=journal mode, ext4 now supports
large folios for regular files. Enable this feature by default. However,
since we cannot change the folio order limitation of mappings on active
inodes, setting the journal=data mode via ioctl on an active inode will
not take immediate effect in non-delalloc mode.

Signed-off-by: Zhang Yi <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Theodore Ts'o <[e-mail]>

fs/ext4/ext4.h

···
 				     struct buffer_head *bh));
 int do_journal_get_write_access(handle_t *handle, struct inode *inode,
 				struct buffer_head *bh);
+bool ext4_should_enable_large_folio(struct inode *inode);
 #define FALL_BACK_TO_NONDELALLOC 1
 #define CONVERT_INLINE_DATA	 2
 

fs/ext4/ext4_jbd2.c

···
 	    ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE) ||
 	    test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
 	    (ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA) &&
-	    !test_opt(inode->i_sb, DELALLOC))) {
+	    !test_opt(inode->i_sb, DELALLOC) &&
+	    !mapping_large_folio_support(inode->i_mapping))) {
 		/* We do not support data journalling for encrypted data */
 		if (S_ISREG(inode->i_mode) && IS_ENCRYPTED(inode))
 			return EXT4_INODE_ORDERED_DATA_MODE;  /* ordered */

fs/ext4/ialloc.c

···
 		}
 	}
 
+	if (ext4_should_enable_large_folio(inode))
+		mapping_set_large_folios(inode->i_mapping);
+
 	ext4_update_inode_fsync_trans(handle, inode, 1);
 
 	err = ext4_mark_inode_dirty(handle, inode);

fs/ext4/inode.c

···
 	return -EFSCORRUPTED;
 }
 
+bool ext4_should_enable_large_folio(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+
+	if (!S_ISREG(inode->i_mode))
+		return false;
+	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
+	    ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA))
+		return false;
+	if (ext4_has_feature_verity(sb))
+		return false;
+	if (ext4_has_feature_encrypt(sb))
+		return false;
+
+	return true;
+}
+
 struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
 			  ext4_iget_flags flags, const char *function,
 			  unsigned int line)
···
 		ret = -EFSCORRUPTED;
 		goto bad_inode;
 	}
+	if (ext4_should_enable_large_folio(inode))
+		mapping_set_large_folios(inode->i_mapping);
+
 	ret = check_igot_inode(inode, flags, function, line);
 	/*
 	 * -ESTALE here means there is nothing inherently wrong with the inode,