Handle the case where unix-dotfile is used with URI parameter nolock=1.

FossilOrigin-Name: 3925a5b904e159d54455cfc73fe837a9c6ea3a6d60da63afde3242b4d6f67c90

1 files changed, 12 insertions, 7 deletions

diff --git a/src/os_unix.c b/src/os_unix.c
index 45ba0c001..c94c0c111 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -2279,16 +2279,21 @@ static int nolockClose(sqlite3_file *id) {
 
 /*
 ** This routine checks if there is a RESERVED lock held on the specified
-** file by this or any other process. The caller always holds a SHARED
-** lock when it is called. This means that no other connection could
-** hold a RESERVED lock, as unix-dotfile uses just a single exclusive lock -
-** the presence of the dotfile - for all 4 VFS locks. So this function sets
-** (*pResOut) to 0 (no other connection holds RESERVED) and returns SQLITE_OK.
+** file by this or any other process. If the caller holds a SHARED
+** or greater lock when it is called, then it is assumed that no other
+** client may hold RESERVED. Or, if the caller holds no lock, then it
+** is assumed another client holds RESERVED if the lock-file exists.
 */
 static int dotlockCheckReservedLock(sqlite3_file *id, int *pResOut) {
+  unixFile *pFile = (unixFile*)id;
   SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
-  assert( ((unixFile*)id)->eFileLock>=SHARED_LOCK );
-  *pResOut = 0;
+
+  if( pFile->eFileLock>=SHARED_LOCK ){
+    *pResOut = 0;
+  }else{
+    *pResOut = osAccess((const char*)pFile->lockingContext, 0)==0;
+  }
+  OSTRACE(("TEST WR-LOCK %d %d %d (dotlock)\n", pFile->h, 0, *pResOut));
   return SQLITE_OK;
 }