From 0c371f1b98031959850aee2e6b642f8b2a86b1d6 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Sun, 21 Dec 2014 13:31:27 +1100
Subject: [PATCH] DataFlash: don't try and open logfile on failure more than
 once

this prevents a corrupted microSD card from causing a continuous
attempt to open a log file while in flight, which can cause large
scheduler delays

Pair-Programmed-With: Grant Morphett <grant@gmorph.com>
---
 libraries/DataFlash/DataFlash_File.cpp | 37 ++++++++++++++++++++------
 libraries/DataFlash/DataFlash_File.h   |  1 +
 2 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/libraries/DataFlash/DataFlash_File.cpp b/libraries/DataFlash/DataFlash_File.cpp
index 48c659e1b7..6ac3f1c347 100644
--- a/libraries/DataFlash/DataFlash_File.cpp
+++ b/libraries/DataFlash/DataFlash_File.cpp
@@ -39,6 +39,7 @@ DataFlash_File::DataFlash_File(const char *log_directory) :
     _read_offset(0),
     _write_offset(0),
     _initialised(false),
+    _open_error(false),
     _log_directory(log_directory),
     _writebuf(NULL),
     _writebuf_size(16*1024),
@@ -128,7 +129,7 @@ void DataFlash_File::Init(const struct LogStructure *structure, uint8_t num_type
 // return true for CardInserted() if we successfully initialised
 bool DataFlash_File::CardInserted(void)
 {
-    return _initialised;
+    return _initialised && !_open_error;
 }
 
 
@@ -195,7 +196,7 @@ void DataFlash_File::EraseAll()
 /* Write a block of data at current offset */
 void DataFlash_File::WriteBlock(const void *pBuffer, uint16_t size)
 {
-    if (_write_fd == -1 || !_initialised || !_writes_enabled) {
+    if (_write_fd == -1 || !_initialised || _open_error || !_writes_enabled) {
         return;
     }
     uint16_t _head;
@@ -232,7 +233,7 @@ void DataFlash_File::WriteBlock(const void *pBuffer, uint16_t size)
 */
 void DataFlash_File::ReadBlock(void *pkt, uint16_t size)
 {
-    if (_read_fd == -1 || !_initialised) {
+    if (_read_fd == -1 || !_initialised || _open_error) {
         return;
     }
 
@@ -311,7 +312,7 @@ void DataFlash_File::get_log_boundaries(uint16_t log_num, uint16_t & start_page,
  */
 int16_t DataFlash_File::get_log_data(uint16_t log_num, uint16_t page, uint32_t offset, uint16_t len, uint8_t *data)
 {
-    if (!_initialised) {
+    if (!_initialised || _open_error) {
         return -1;
     }
     if (_read_fd != -1 && log_num != _read_fd_log_num) {
@@ -325,10 +326,17 @@ int16_t DataFlash_File::get_log_data(uint16_t log_num, uint16_t page, uint32_t o
         }
         stop_logging();
         _read_fd = ::open(fname, O_RDONLY);
-        free(fname);
         if (_read_fd == -1) {
+            _open_error = true;
+            int saved_errno = errno;
+            ::printf("Log read open fail for %s - %s\n",
+                     fname, strerror(saved_errno));
+            hal.console->printf("Log read open fail for %s - %s\n",
+                                fname, strerror(saved_errno));
+            free(fname);
             return -1;            
         }
+        free(fname);
         _read_offset = 0;
         _read_fd_log_num = log_num;
     }
@@ -408,6 +416,12 @@ uint16_t DataFlash_File::start_new_log(void)
 {
     stop_logging();
 
+    if (_open_error) {
+        // we have previously failed to open a file - don't try again
+        // to prevent us trying to open files while in flight
+        return 0xFFFF;
+    }
+
     if (_read_fd != -1) {
         ::close(_read_fd);
         _read_fd = -1;
@@ -423,11 +437,18 @@ uint16_t DataFlash_File::start_new_log(void)
     }
     char *fname = _log_file_name(log_num);
     _write_fd = ::open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666);
-    free(fname);
     if (_write_fd == -1) {
         _initialised = false;
+        _open_error = true;
+        int saved_errno = errno;
+        ::printf("Log open fail for %s - %s\n",
+                 fname, strerror(saved_errno));
+        hal.console->printf("Log open fail for %s - %s\n",
+                            fname, strerror(saved_errno));
+        free(fname);
         return 0xFFFF;
     }
+    free(fname);
     _write_offset = 0;
     _writebuf_head = 0;
     _writebuf_tail = 0;
@@ -452,7 +473,7 @@ void DataFlash_File::LogReadProcess(uint16_t log_num,
                                     AP_HAL::BetterStream *port)
 {
     uint8_t log_step = 0;
-    if (!_initialised) {
+    if (!_initialised || _open_error) {
         return;
     }
     if (_read_fd != -1) {
@@ -584,7 +605,7 @@ void DataFlash_File::ListAvailableLogs(AP_HAL::BetterStream *port)
 void DataFlash_File::_io_timer(void)
 {
     uint16_t _tail;
-    if (_write_fd == -1 || !_initialised) {
+    if (_write_fd == -1 || !_initialised || _open_error) {
         return;
     }
 
diff --git a/libraries/DataFlash/DataFlash_File.h b/libraries/DataFlash/DataFlash_File.h
index 1bd9657132..ef472e1564 100644
--- a/libraries/DataFlash/DataFlash_File.h
+++ b/libraries/DataFlash/DataFlash_File.h
@@ -58,6 +58,7 @@ private:
     uint32_t _read_offset;
     uint32_t _write_offset;
     volatile bool _initialised;
+    volatile bool _open_error;
     const char *_log_directory;
 
     /*