Unmount all disks before going into USB slave mode

---
 firmware/common/dir_uncached.c |    4 ++--
 firmware/common/disk.c         |   25 ++++++++++++++++++++++++-
 firmware/common/file.c         |    4 ++--
 firmware/drivers/fat.c         |    4 ++--
 firmware/usb.c                 |    2 ++
 5 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/firmware/common/dir_uncached.c b/firmware/common/dir_uncached.c
index e4c4397..5d43166 100644
--- a/firmware/common/dir_uncached.c
+++ b/firmware/common/dir_uncached.c
@@ -36,7 +36,7 @@
 
 static DIR_UNCACHED opendirs[MAX_OPEN_DIRS];
 
-#ifdef HAVE_HOTSWAP
+#if defined(HAVE_HOTSWAP) || defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK))
 // release all dir handles on a given volume "by force", to avoid leaks
 int release_dirs(int volume)
 {
@@ -57,7 +57,7 @@ int release_dirs(int volume)
     }
     return closed; /* return how many we did */
 }
-#endif /* #ifdef HAVE_HOTSWAP */
+#endif /* #if defined(HAVE_HOTSWAP) || defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK)) */
 
 DIR_UNCACHED* opendir_uncached(const char* name)
 {
diff --git a/firmware/common/disk.c b/firmware/common/disk.c
index 6be9b47..649e328 100644
--- a/firmware/common/disk.c
+++ b/firmware/common/disk.c
@@ -23,7 +23,7 @@
 #include "storage.h"
 #include "debug.h"
 #include "fat.h"
-#ifdef HAVE_HOTSWAP
+#if defined(HAVE_HOTSWAP) || defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK))
 #include "dir.h" /* for release_dirs() */
 #include "file.h" /* for release_files() */
 #endif
@@ -257,3 +257,26 @@ int disk_unmount(int drive)
     return unmounted;
 }
 #endif /* #ifdef HAVE_HOTSWAP */
+
+#if defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK))
+int disk_unmount_all(void)
+{
+    int unmounted = 0;
+    int i;
+    mutex_lock(&disk_mutex);
+    for (i=0; i<NUM_VOLUMES; i++)
+    {
+        if (vol_drive[i] != -1)
+        {   /* force releasing resources */
+            vol_drive[i] = -1; /* mark unused */
+            unmounted++;
+            release_files(i);
+            release_dirs(i);
+            fat_unmount(i, false);
+        }
+    }
+    mutex_unlock(&disk_mutex);
+
+    return unmounted;
+}
+#endif /* defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK)) */
diff --git a/firmware/common/file.c b/firmware/common/file.c
index da85846..0278444 100644
--- a/firmware/common/file.c
+++ b/firmware/common/file.c
@@ -793,7 +793,7 @@ off_t filesize(int fd)
 }
 
 
-#ifdef HAVE_HOTSWAP
+#if defined(HAVE_HOTSWAP) || defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK))
 /* release all file handles on a given volume "by force", to avoid leaks */
 int release_files(int volume)
 {
@@ -814,4 +814,4 @@ int release_files(int volume)
     }
     return closed; /* return how many we did */
 }
-#endif /* #ifdef HAVE_HOTSWAP */
+#endif /* #if defined(HAVE_HOTSWAP) || defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK)) */
diff --git a/firmware/drivers/fat.c b/firmware/drivers/fat.c
index cff11d2..70ffb7f 100644
--- a/firmware/drivers/fat.c
+++ b/firmware/drivers/fat.c
@@ -479,7 +479,7 @@ int fat_mount(IF_MV2(int volume,) IF_MD2(int drive,) long startsector)
     return 0;
 }
 
-#ifdef HAVE_HOTSWAP
+#if defined(HAVE_HOTSWAP) || defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK))
 int fat_unmount(int volume, bool flush)
 {
     int rc;
@@ -518,7 +518,7 @@ int fat_unmount(int volume, bool flush)
 #endif
     return rc;
 }
-#endif /* #ifdef HAVE_HOTSWAP */
+#endif /* #if defined(HAVE_HOTSWAP) || defined(USE_ROCKBOX_USB) || (!defined(USB_NONE) && !defined(HAVE_USBSTACK)) */
 
 void fat_recalc_free(IF_MV_NONVOID(int volume))
 {
diff --git a/firmware/usb.c b/firmware/usb.c
index 9eaf201..6309c14 100644
--- a/firmware/usb.c
+++ b/firmware/usb.c
@@ -131,6 +131,7 @@ static inline void usb_slave_mode(bool on)
 #ifdef HAVE_PRIORITY_SCHEDULING
         thread_set_priority(THREAD_ID_CURRENT, PRIORITY_REALTIME);
 #endif
+        disk_unmount_all();
         usb_attach();
     }
     else /* usb_state == USB_INSERTED (only!) */
@@ -172,6 +173,7 @@ static inline void usb_slave_mode(bool on)
     if(on)
     {
         DEBUGF("Entering USB slave mode\n");
+        disk_unmount_all();
         storage_soft_reset();
         storage_init();
         storage_enable(false);
-- 
1.7.1