From 0540128709bdd046a640d05012455dcc3664f337 Mon Sep 17 00:00:00 2001
From: Kostas Missos <ctcaer@gmail.com>
Date: Wed, 22 Aug 2018 03:42:25 +0300
Subject: [PATCH] Faster backups

- Add file pre-allocations to greatly reduce overhead of FatFS.
This was missing before, because it takes 1.5KB payload size.

Speed bumps (no verify) are between 7 to 30% for exFAT and ~50% for FAT32, depending on the workload.
---
 bootloader/main.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/bootloader/main.c b/bootloader/main.c
index 402eb67..4a835e9 100644
--- a/bootloader/main.c
+++ b/bootloader/main.c
@@ -1023,6 +1023,12 @@ int dump_emmc_part(char *sd_path, sdmmc_storage_t *storage, emmc_part_t *part)
 
 		return 0;
 	}
+	u64 totalSize = (u64)((u64)totalSectors << 9);
+	if (!isSmallSdCard && sd_fs.fs_type == FS_EXFAT)
+		f_lseek(&fp, totalSize);
+	else
+		f_lseek(&fp, MIN(totalSize, multipartSplitSize));
+	f_lseek(&fp, 0);
 
 	u32 numSectorsPerIter = 0;
 	if (totalSectors > 0x200000)
@@ -1122,6 +1128,10 @@ int dump_emmc_part(char *sd_path, sdmmc_storage_t *storage, emmc_part_t *part)
 				return 0;
 			}
 			bytesWritten = 0;
+
+			totalSize = (u64)((u64)totalSectors << 9);
+			f_lseek(&fp, MIN(totalSize, multipartSplitSize));
+			f_lseek(&fp, 0);
 		}
 
 		retryCount = 0;
@@ -1141,6 +1151,8 @@ int dump_emmc_part(char *sd_path, sdmmc_storage_t *storage, emmc_part_t *part)
 
 				free(buf);
 				f_close(&fp);
+				f_unlink(outFilename);
+
 				return 0;
 			}
 		}
@@ -1153,6 +1165,8 @@ int dump_emmc_part(char *sd_path, sdmmc_storage_t *storage, emmc_part_t *part)
 
 			free(buf);
 			f_close(&fp);
+			f_unlink(outFilename);
+
 			return 0;
 		}
 		pct = (u64)((u64)(lba_curr - part->lba_start) * 100u) / (u64)(part->lba_end - part->lba_start);