ext4: update quota information while swapping boot loader inode

While do swap between two inode, they swap i_data without update
quota information. Also, swap_inode_boot_loader can do "revert"
somtimes, so update the quota while all operations has been finished.
Signed-off-by: yangerkun <yangerkun@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

fs/ext4/ioctl.c

@@ -68,8 +68,6 @@ static void swap_inode_data(struct inode *inode1, struct inode *inode2)
 	ei2 = EXT4_I(inode2);
 
 	swap(inode1->i_version, inode2->i_version);
-	swap(inode1->i_blocks, inode2->i_blocks);
-	swap(inode1->i_bytes, inode2->i_bytes);
 	swap(inode1->i_atime, inode2->i_atime);
 	swap(inode1->i_mtime, inode2->i_mtime);
 
@@ -115,6 +113,9 @@ static long swap_inode_boot_loader(struct super_block *sb,
 	int err;
 	struct inode *inode_bl;
 	struct ext4_inode_info *ei_bl;
+	qsize_t size, size_bl, diff;
+	blkcnt_t blocks;
+	unsigned short bytes;
 
 	inode_bl = ext4_iget(sb, EXT4_BOOT_LOADER_INO, EXT4_IGET_SPECIAL);
 	if (IS_ERR(inode_bl))
@@ -180,6 +181,13 @@ static long swap_inode_boot_loader(struct super_block *sb,
 			memset(ei_bl->i_data, 0, sizeof(ei_bl->i_data));
 	}
 
+	err = dquot_initialize(inode);
+	if (err)
+		goto err_out1;
+
+	size = (qsize_t)(inode->i_blocks) * (1 << 9) + inode->i_bytes;
+	size_bl = (qsize_t)(inode_bl->i_blocks) * (1 << 9) + inode_bl->i_bytes;
+	diff = size - size_bl;
 	swap_inode_data(inode, inode_bl);
 
 	inode->i_ctime = inode_bl->i_ctime = current_time(inode);
@@ -193,24 +201,46 @@ static long swap_inode_boot_loader(struct super_block *sb,
 
 	err = ext4_mark_inode_dirty(handle, inode);
 	if (err < 0) {
+		/* No need to update quota information. */
 		ext4_warning(inode->i_sb,
 			"couldn't mark inode #%lu dirty (err %d)",
 			inode->i_ino, err);
 		/* Revert all changes: */
 		swap_inode_data(inode, inode_bl);
 		ext4_mark_inode_dirty(handle, inode);
-	} else {
-		err = ext4_mark_inode_dirty(handle, inode_bl);
-		if (err < 0) {
-			ext4_warning(inode_bl->i_sb,
-				"couldn't mark inode #%lu dirty (err %d)",
-				inode_bl->i_ino, err);
-			/* Revert all changes: */
-			swap_inode_data(inode, inode_bl);
-			ext4_mark_inode_dirty(handle, inode);
-			ext4_mark_inode_dirty(handle, inode_bl);
-		}
+		goto err_out1;
+	}
+
+	blocks = inode_bl->i_blocks;
+	bytes = inode_bl->i_bytes;
+	inode_bl->i_blocks = inode->i_blocks;
+	inode_bl->i_bytes = inode->i_bytes;
+	err = ext4_mark_inode_dirty(handle, inode_bl);
+	if (err < 0) {
+		/* No need to update quota information. */
+		ext4_warning(inode_bl->i_sb,
+			"couldn't mark inode #%lu dirty (err %d)",
+			inode_bl->i_ino, err);
+		goto revert;
 	}
+
+	/* Bootloader inode should not be counted into quota information. */
+	if (diff > 0)
+		dquot_free_space(inode, diff);
+	else
+		err = dquot_alloc_space(inode, -1 * diff);
+
+	if (err < 0) {
+revert:
+		/* Revert all changes: */
+		inode_bl->i_blocks = blocks;
+		inode_bl->i_bytes = bytes;
+		swap_inode_data(inode, inode_bl);
+		ext4_mark_inode_dirty(handle, inode);
+		ext4_mark_inode_dirty(handle, inode_bl);
+	}
+
+err_out1:
 	ext4_journal_stop(handle);
 	ext4_double_up_write_data_sem(inode, inode_bl);