From 0a62ffbc2fa1917e29dbd751ff29be9e164e4c12 Mon Sep 17 00:00:00 2001
From: Zach Brown <zab@versity.com>
Date: Thu, 14 Jun 2018 14:10:28 -0700
Subject: [PATCH] scoutfs-utils: buffer staging

The stage command was trivially implemented by allocating, reading, and
staging the entire region in buffer.  This is unreasonable for large
file regions.  Implement the stage command by having it read each
portion of the region into a smaller buffer, starting with a meg.

Signed-off-by: Zach Brown <zab@versity.com>
---
 utils/src/stage_release.c | 54 ++++++++++++++++++++++++---------------
 1 file changed, 34 insertions(+), 20 deletions(-)

diff --git a/utils/src/stage_release.c b/utils/src/stage_release.c
index 293f012d..2e1ec342 100644
--- a/utils/src/stage_release.c
+++ b/utils/src/stage_release.c
@@ -18,6 +18,8 @@
 static int stage_cmd(int argc, char **argv)
 {
 	struct scoutfs_ioctl_stage args;
+	unsigned int buf_len = 1024 * 1024;
+	unsigned int bytes;
 	char *endptr = NULL;
 	char *buf = NULL;
 	int afd = -1;
@@ -82,33 +84,45 @@ static int stage_cmd(int argc, char **argv)
 		goto out;
 	}
 
-	buf = malloc(count);
+	buf = malloc(buf_len);
 	if (!buf) {
-		fprintf(stderr, "couldn't allocate %llu byte buffer\n",
-			count);
+		fprintf(stderr, "couldn't allocate %u byte buffer\n", buf_len);
 		ret = -ENOMEM;
 		goto out;
 	}
 
-	ret = read(afd, buf, count);
-	if (ret < count) {
-		fprintf(stderr, "archive read returned %d, not %llu: error %s (%d)\n",
-			ret, count, strerror(errno), errno);
-		ret = -EIO;
-		goto out;
+	while (count) {
+
+		bytes = min(count, buf_len);
+
+		ret = read(afd, buf, bytes);
+		if (ret <= 0) {
+			fprintf(stderr, "archive read returned %d: error %s (%d)\n",
+				ret, strerror(errno), errno);
+			ret = -EIO;
+			goto out;
+		}
+
+		bytes = ret;
+
+		args.data_version = vers;
+		args.buf_ptr = (unsigned long)buf;
+		args.offset = offset;
+		args.count = bytes;
+
+		count -= bytes;
+		offset += bytes;
+
+		ret = ioctl(fd, SCOUTFS_IOC_STAGE, &args);
+		if (ret != bytes) {
+			fprintf(stderr, "stage returned %d, not %u: error %s (%d)\n",
+				ret, bytes, strerror(errno), errno);
+			ret = -EIO;
+			goto out;
+		}
 	}
 
-	args.data_version = vers;
-	args.buf_ptr = (unsigned long)buf;
-	args.offset = offset;
-	args.count = count;
-
-	ret = ioctl(fd, SCOUTFS_IOC_STAGE, &args);
-	if (ret < count) {
-		fprintf(stderr, "stage returned %d, not %llu: error %s (%d)\n",
-			ret, count, strerror(errno), errno);
-		ret = -EIO;
-	}
+	ret = 0;
 out:
 	free(buf);
 	if (fd > -1)