AP_Filesystem: added interface for mount/unmount

we need to hold the FATFS semaphore when doing mount/unmount, which
means we must go via AP_Filesystem_FATFS

libraries/AP_Filesystem/AP_Filesystem.cpp

@@ -57,7 +57,7 @@ const AP_Filesystem::Backend AP_Filesystem::backends[] = {
 
 #define MAX_FD_PER_BACKEND 256U
 #define NUM_BACKENDS ARRAY_SIZE(backends)
-#define LOCAL_BACKEND backends[0];
+#define LOCAL_BACKEND backends[0]
 #define BACKEND_IDX(backend) (&(backend) - &backends[0])
 
 /*
@@ -215,6 +215,18 @@ bool AP_Filesystem::set_mtime(const char *filename, const uint32_t mtime_sec)
     return backend.fs.set_mtime(filename, mtime_sec);
 }
 
+// if filesystem is not running then try a remount
+bool AP_Filesystem::retry_mount(void)
+{
+    return LOCAL_BACKEND.fs.retry_mount();
+}
+
+// unmount filesystem for reboot
+void AP_Filesystem::unmount(void)
+{
+    return LOCAL_BACKEND.fs.unmount();
+}
+
 namespace AP
 {
 AP_Filesystem &FS()

libraries/AP_Filesystem/AP_Filesystem.h

@@ -83,6 +83,12 @@ public:
     // set modification time on a file
     bool set_mtime(const char *filename, const uint32_t mtime_sec);
 
+    // if filesystem is not running then try a remount. Return true if fs is mounted
+    bool retry_mount(void);
+
+    // unmount filesystem for reboot
+    void unmount(void);
+    
 private:
     struct Backend {
         const char *prefix;

libraries/AP_Filesystem/AP_Filesystem_FATFS.cpp

@@ -817,6 +817,24 @@ bool AP_Filesystem_FATFS::set_mtime(const char *filename, const uint32_t mtime_s
     return f_utime(filename, (FILINFO *)&fno) == FR_OK;
 }
 
+/*
+  retry mount of filesystem if needed
+*/
+bool AP_Filesystem_FATFS::retry_mount(void)
+{
+    WITH_SEMAPHORE(sem);
+    return sdcard_retry();
+}
+
+/*
+  unmount filesystem for reboot
+*/
+void AP_Filesystem_FATFS::unmount(void)
+{
+    WITH_SEMAPHORE(sem);
+    return sdcard_stop();
+}
+
 /*
   convert POSIX errno to text with user message.
 */

libraries/AP_Filesystem/AP_Filesystem_FATFS.h

@@ -48,4 +48,10 @@ public:
 
     // set modification time on a file
     bool set_mtime(const char *filename, const uint32_t mtime_sec) override;
+
+    // retry mount of filesystem if needed
+    bool retry_mount(void) override;
+
+    // unmount filesystem for reboot
+    void unmount(void) override;
 };

libraries/AP_Filesystem/AP_Filesystem_backend.h

@@ -49,4 +49,10 @@ public:
 
     // set modification time on a file
     virtual bool set_mtime(const char *filename, const uint32_t mtime_sec) { return false; }
+
+    // retry mount of filesystem if needed
+    virtual bool retry_mount(void) { return true; }
+
+    // unmount filesystem for reboot
+    virtual void unmount(void) {}
 };