From e4386c8cc0f7f2cfb09781d963b353310a3cd93a Mon Sep 17 00:00:00 2001
From: Karel Zak
Date: Wed, 12 Sep 2018 13:18:08 +0200
Subject: libfdisk: accept grain script header

The "grain" variable is used to calculate partitions alignment. The
default is 1MiB (or minimal I/O size). The libfdisk provides API to overwrite
this default, but this feature has been nowhere accessible for
end-user.

This patch support for "grain: <size>" in libfdisk scripts.

Addresses: https://github.com/karelzak/util-linux/issues/688
Signed-off-by: Karel Zak <kzak@redhat.com>
---
 libfdisk/src/alignment.c |  1 +
 libfdisk/src/script.c    | 24 +++++++++++++++++++++++-
 2 files changed, 24 insertions(+), 1 deletion(-)

(limited to 'libfdisk/src')

diff --git a/libfdisk/src/alignment.c b/libfdisk/src/alignment.c
index 891285aaa..a238c7bf0 100644
--- a/libfdisk/src/alignment.c
+++ b/libfdisk/src/alignment.c
@@ -338,6 +338,7 @@ int fdisk_save_user_grain(struct fdisk_context *cxt, unsigned long grain)
 	if (!cxt || grain % 512)
 		return -EINVAL;
 
+	DBG(CXT, ul_debugobj(cxt, "user grain size: %lu", grain));
 	cxt->user_grain = grain;
 	return 0;
 }
diff --git a/libfdisk/src/script.c b/libfdisk/src/script.c
index 1970e7b66..24c40f8ce 100644
--- a/libfdisk/src/script.c
+++ b/libfdisk/src/script.c
@@ -241,7 +241,6 @@ const char *fdisk_script_get_header(struct fdisk_script *dp, const char *name)
 	return fi ? fi->data : NULL;
 }
 
-
 /**
  * fdisk_script_set_header:
  * @dp: script instance
@@ -447,6 +446,14 @@ int fdisk_script_read_context(struct fdisk_script *dp, struct fdisk_context *cxt
 		}
 	}
 
+	if (!rc && fdisk_get_grain_size(cxt) != 2048 * 512) {
+		char buf[64];
+
+		snprintf(buf, sizeof(buf), "%zu", fdisk_get_grain_size(cxt));
+		rc = fdisk_script_set_header(dp, "grain", buf);
+	}
+
+
 	DBG(SCRIPT, ul_debugobj(dp, "read context done [rc=%d]", rc));
 	return rc;
 }
@@ -759,6 +766,7 @@ static int parse_line_header(struct fdisk_script *dp, char *s)
 			goto done;			/* only "sectors" supported */
 	} else if (strcmp(name, "label-id") == 0
 		   || strcmp(name, "device") == 0
+		   || strcmp(name, "grain") == 0
 		   || strcmp(name, "first-lba") == 0
 		   || strcmp(name, "last-lba") == 0
 		   || strcmp(name, "table-length") == 0) {
@@ -1432,6 +1440,20 @@ int fdisk_apply_script_headers(struct fdisk_context *cxt, struct fdisk_script *d
 	DBG(SCRIPT, ul_debugobj(dp, "applying script headers"));
 	fdisk_set_script(cxt, dp);
 
+	str = fdisk_script_get_header(dp, "grain");
+	if (str) {
+		uintmax_t sz;
+
+		rc = parse_size(str, &sz, NULL);
+		if (rc == 0)
+			rc = fdisk_save_user_grain(cxt, sz);
+		if (rc)
+			return rc;
+	}
+
+	if (fdisk_has_user_device_properties(cxt))
+		fdisk_apply_user_device_properties(cxt);
+
 	/* create empty label */
 	name = fdisk_script_get_header(dp, "label");
 	if (!name)
-- 
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