[Suspend2][ 21/35] [Suspend2] Make modifications to the filewriter signature.

[Nigel Cunningham <nigel@suspend2.net>]

Implement support for invalidating an image or marking that we've attempted
to resume from the image before.

Signed-off-by: Nigel Cunningham <nigel@suspend2.net>

 kernel/power/suspend_file.c |   51 +++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 51 insertions(+), 0 deletions(-)

diff --git a/kernel/power/suspend_file.c b/kernel/power/suspend_file.c
index 8e4431c..4df05c8 100644
--- a/kernel/power/suspend_file.c
+++ b/kernel/power/suspend_file.c
@@ -663,3 +663,54 @@ static int filewriter_read_header_cleanu
 	return 0;
 }
 
+static int filewriter_signature_op(int op)
+{
+	char *cur;
+	int result = 0, changed = 0;
+	struct filewriter_header *header;
+	
+	if(filewriter_target_bdev <= 0)
+		return -1;
+
+	cur = (char *) get_zeroed_page(GFP_ATOMIC);
+	if (!cur) {
+		printk("Unable to allocate a page for reading the image "
+				"signature.\n");
+		return -ENOMEM;
+	}
+
+	suspend_bio_ops.bdev_page_io(READ, filewriter_target_bdev,
+			target_firstblock,
+			virt_to_page(cur));
+
+	header = (struct filewriter_header *) cur;
+	result = parse_signature(header);
+		
+	switch (op) {
+		case INVALIDATE:
+			if (result == -1)
+				goto out;
+
+			strcpy(header->sig, NoImage);
+			header->resumed_before = 0;
+			result = changed = 1;
+			break;
+		case MARK_RESUME_ATTEMPTED:
+			if (result == 1) {
+				header->resumed_before = 1;
+				changed = 1;
+			}
+			break;
+	}
+
+	if (changed)
+		suspend_bio_ops.bdev_page_io(WRITE, filewriter_target_bdev,
+				target_firstblock,
+				virt_to_page(cur));
+
+out:
+	suspend_bio_ops.finish_all_io();
+	free_page((unsigned long) cur);
+	return result;
+}
+

--
Nigel Cunningham		nigel at suspend2 dot net