[PATCH 1/2] erofs-utils: lib: fix erofs_io_sendfile() again

[Gao Xiang]

The number of bytes written should be returned.

Fixes: 29466e7f1cbf ("erofs-utils: lib: fix erofs_io_sendfile()")
Signed-off-by: Gao Xiang <hsiangkao at linux.alibaba.com>
---
 lib/io.c     | 13 +++++++------
 mount/main.c | 12 ++++++------
 2 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/lib/io.c b/lib/io.c
index 440f69b..90d2e54 100644
--- a/lib/io.c
+++ b/lib/io.c
@@ -581,6 +581,7 @@ ssize_t erofs_io_sendfile(struct erofs_vfile *vout, struct erofs_vfile *vin,
 			  off_t *pos, size_t count)
 {
 	ssize_t read, written;
+	size_t rem = count;
 
 	if (vin->ops || vout->ops) {
 		if (vin->ops && vin->ops->sendfile)
@@ -600,13 +601,13 @@ ssize_t erofs_io_sendfile(struct erofs_vfile *vout, struct erofs_vfile *vin,
 			}
 			break;
 		}
-		count -= written;
+		rem -= written;
 	} while (written);
 #endif
-	while (count) {
+	while (rem) {
 		char buf[max(EROFS_MAX_BLOCK_SIZE, 32768)];
 
-		read = min_t(u64, count, sizeof(buf));
+		read = min_t(u64, rem, sizeof(buf));
 		if (pos)
 			read = erofs_io_pread(vin, buf, read, *pos);
 		else
@@ -615,17 +616,17 @@ ssize_t erofs_io_sendfile(struct erofs_vfile *vout, struct erofs_vfile *vin,
 			written = read;
 			break;
 		}
-		count -= read;
+		rem -= read;
 		if (pos)
 			*pos += read;
 		do {
 			written = erofs_io_write(vout, buf, read);
 			if (written < 0)
-				break;
+				return written;
 			read -= written;
 		} while (read);
 	}
-	return written < 0 ? written : count;
+	return written < 0 ? written : count - rem;
 }
 
 int erofs_io_xcopy(struct erofs_vfile *vout, off_t pos,
diff --git a/mount/main.c b/mount/main.c
index 53bd2b2..e25134c 100644
--- a/mount/main.c
+++ b/mount/main.c
@@ -577,7 +577,7 @@ static void *erofsmount_nbd_loopfn(void *arg)
 
 	while (1) {
 		struct erofs_nbd_request rq;
-		ssize_t rem;
+		ssize_t written;
 		off_t pos;
 
 		err = erofs_nbd_get_request(ctx->sk.fd, &rq);
@@ -597,13 +597,13 @@ static void *erofsmount_nbd_loopfn(void *arg)
 		erofs_nbd_send_reply_header(ctx->sk.fd, rq.cookie, 0);
 		pos = rq.from;
 		do {
-			rem = erofs_io_sendfile(&ctx->sk, &ctx->vd, &pos, rq.len);
-			if (rem == -EINTR) {
-				err = rem;
+			written = erofs_io_sendfile(&ctx->sk, &ctx->vd, &pos, rq.len);
+			if (written == -EINTR) {
+				err = written;
 				goto out;
 			}
-		} while (rem < 0);
-		err = __erofs_0write(ctx->sk.fd, rem);
+		} while (written < 0);
+		err = __erofs_0write(ctx->sk.fd, rq.len - written);
 		if (err) {
 			if (err > 0)
 				err = -EIO;
-- 
2.43.5