bch: fix sector buffer invalidation issue

drivers/bch/bch.h

@@ -81,7 +81,7 @@ EXTERN const struct file_operations g_bch_fops;
  * Public Function Prototypes
  ****************************************************************************/
 
-EXTERN int  bchlib_flushsector(FAR struct bchlib_s *bch);
+EXTERN int  bchlib_flushsector(FAR struct bchlib_s *bch, bool discard);
 EXTERN int  bchlib_readsector(FAR struct bchlib_s *bch, size_t sector);
 
 #undef EXTERN

drivers/bch/bchdev_driver.c

@@ -168,7 +168,7 @@ static int bch_close(FAR struct file *filep)
 
   /* Flush any dirty pages remaining in the cache */
 
-  bchlib_flushsector(bch);
+  bchlib_flushsector(bch, false);
 
   /* Decrement the reference count (I don't use bchlib_decref() because I
    * want the entire close operation to be atomic wrt other driver
@@ -424,7 +424,7 @@ static int bch_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
         {
           /* Flush any dirty pages remaining in the cache */
 
-          ret = bchlib_flushsector(bch);
+          ret = bchlib_flushsector(bch, false);
         }
         break;
 

drivers/bch/bchlib_cache.c

@@ -103,7 +103,7 @@ static int bch_cypher(FAR struct bchlib_s *bch, int encrypt)
  *
  ****************************************************************************/
 
-int bchlib_flushsector(FAR struct bchlib_s *bch)
+int bchlib_flushsector(FAR struct bchlib_s *bch, bool discard)
 {
   FAR struct inode *inode;
   ssize_t ret = OK;
@@ -144,6 +144,11 @@ int bchlib_flushsector(FAR struct bchlib_s *bch)
       bch->dirty = false;
     }
 
+  if (discard)
+    {
+      bch->sector = (size_t)-1;
+    }
+
   return (int)ret;
 }
 
@@ -151,7 +156,7 @@ int bchlib_flushsector(FAR struct bchlib_s *bch)
  * Name: bchlib_readsector
  *
  * Description:
- *   Flush the current contents of the sector buffer (if dirty)
+ *   Read the current sector contents into buffer
  *
  * Assumptions:
  *   Caller must assume mutual exclusion
@@ -167,15 +172,13 @@ int bchlib_readsector(FAR struct bchlib_s *bch, size_t sector)
     {
       inode = bch->inode;
 
-      ret = bchlib_flushsector(bch);
+      ret = bchlib_flushsector(bch, true);
       if (ret < 0)
         {
           ferr("Flush failed: %zd\n", ret);
           return (int)ret;
         }
 
-      bch->sector = (size_t)-1;
-
       ret = inode->u.i_bops->read(inode, bch->buffer, sector, 1);
       if (ret < 0)
         {

drivers/bch/bchlib_teardown.c

@@ -43,8 +43,7 @@
  * Name: bchlib_teardown
  *
  * Description:
- *   Setup so that the block driver referenced by 'blkdev' can be accessed
- *   similar to a character device.
+ *   Close the block driver and free resources
  *
  ****************************************************************************/
 
@@ -63,7 +62,7 @@ int bchlib_teardown(FAR void *handle)
 
   /* Flush any pending data to the block driver */
 
-  bchlib_flushsector(bch);
+  bchlib_flushsector(bch, false);
 
   /* Close the block driver */
 

drivers/bch/bchlib_write.c

@@ -133,7 +133,8 @@ ssize_t bchlib_write(FAR void *handle, FAR const char *buffer, size_t offset,
 
       /* Flush the dirty sector to keep the sector sequence */
 
-      ret = bchlib_flushsector(bch);
+      ret = bchlib_flushsector(bch, sector <= bch->sector &&
+                               bch->sector < (sector + nsectors));
       if (ret < 0)
         {
           ferr("ERROR: Flush failed: %d\n", ret);