From 3027cfe5436a2d7802a9b264cc5e329ee5de116b Mon Sep 17 00:00:00 2001
From: JING <chenjing139@huawei.com>
Date: Thu, 22 Apr 2021 11:12:28 +0800
Subject: [PATCH] fix ftruncate

---
 fs/fat/os_adapt/fatfs.c | 18 ++++++++++++++----
 fs/fat/os_adapt/fatfs.h |  6 +++---
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/fs/fat/os_adapt/fatfs.c b/fs/fat/os_adapt/fatfs.c
index 8a671370..fd0f2210 100644
--- a/fs/fat/os_adapt/fatfs.c
+++ b/fs/fat/os_adapt/fatfs.c
@@ -171,6 +171,19 @@ int fatfs_2_vfs(int result)
     return status;
 }
 
+static bool fatfs_is_last_cluster(FATFS *fs, DWORD cclust)
+{
+    switch (fs->fs_type) {
+        case FS_FAT12:
+            return (cclust == FAT12_END_OF_CLUSTER);
+        case FS_FAT16:
+            return (cclust == FAT16_END_OF_CLUSTER);
+        case FS_FAT32:
+        default:
+            return (cclust == FAT32_END_OF_CLUSTER);
+    }
+}
+
 static int fatfs_sync(unsigned long mountflags, FATFS *fs)
 {
 #ifdef LOSCFG_FS_FAT_CACHE
@@ -806,10 +819,7 @@ static FRESULT realloc_cluster(FILINFO *finfo, FFOBJID *obj, FSIZE_t size)
     if ((cclust == BAD_CLUSTER) || (cclust == DISK_ERROR)) {
         return FR_DISK_ERR;
     }
-    if ((obj->fs->fs_type == FS_FAT12 && cclust != FAT12_END_OF_FILE) ||
-        (obj->fs->fs_type == FS_FAT16 && cclust != FAT16_END_OF_FILE) ||
-        (obj->fs->fs_type == FS_FAT32 && cclust != FAT32_END_OF_FILE)) {
-        /* Remove extra cluster if existing */
+    if (!fatfs_is_last_cluster(obj->fs, cclust)) { /* Remove extra cluster if existing */
         result = remove_chain(obj, cclust, pclust);
         if (result != FR_OK) {
             return result;
diff --git a/fs/fat/os_adapt/fatfs.h b/fs/fat/os_adapt/fatfs.h
index f387a682..a7f63089 100644
--- a/fs/fat/os_adapt/fatfs.h
+++ b/fs/fat/os_adapt/fatfs.h
@@ -55,9 +55,9 @@ extern "C" {
 #define FAT32_MAXSIZE          0x100000000
 #define BAD_CLUSTER            0x7FFFFFFF
 #define DISK_ERROR             0xFFFFFFFF
-#define FAT12_END_OF_FILE      0x00000FFF
-#define FAT16_END_OF_FILE      0x0000FFFF
-#define FAT32_END_OF_FILE      0x0FFFFFFF
+#define FAT12_END_OF_CLUSTER   0x00000FFF
+#define FAT16_END_OF_CLUSTER   0x0000FFFF
+#define FAT32_END_OF_CLUSTER   0x0FFFFFFF
 #define FAT_ERROR              (-1)
 
 /* MBR */
-- 
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