fuse: Track process write operations in both direct and writethrough modes

Due to the fact that fuse does not count the write IO of processes in the
direct and writethrough write modes, user processes cannot track
write_bytes through the “/proc/[pid]/io” path. For example, the system
tool iotop cannot count the write operations of the corresponding process.
Signed-off-by: Zhou Jifeng <zhoujifeng@kylinos.com.cn>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/fuse/file.c

@@ -20,6 +20,7 @@
 #include <linux/fs.h>
 #include <linux/filelock.h>
 #include <linux/splice.h>
+#include <linux/task_io_accounting_ops.h>
 
 static int fuse_send_open(struct fuse_mount *fm, u64 nodeid,
 			  unsigned int open_flags, int opcode,
@@ -1405,7 +1406,7 @@ static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	struct address_space *mapping = file->f_mapping;
 	ssize_t written = 0;
 	struct inode *inode = mapping->host;
-	ssize_t err;
+	ssize_t err, count;
 	struct fuse_conn *fc = get_fuse_conn(inode);
 
 	if (fc->writeback_cache) {
@@ -1427,10 +1428,12 @@ static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
 writethrough:
 	inode_lock(inode);
 
-	err = generic_write_checks(iocb, from);
+	err = count = generic_write_checks(iocb, from);
 	if (err <= 0)
 		goto out;
 
+	task_io_account_write(count);
+
 	err = file_remove_privs(file);
 	if (err)
 		goto out;
@@ -1668,6 +1671,7 @@ static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	fuse_dio_lock(iocb, from, &exclusive);
 	res = generic_write_checks(iocb, from);
 	if (res > 0) {
+		task_io_account_write(res);
 		if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
 			res = fuse_direct_IO(iocb, from);
 		} else {