Only error out on a database file move when attempting to start a write

transaction.  Assume read transactions are still safe.  And make the error
SQLITE_READONLY_DBMOVED instead of SQLITE_IOERR_NODB.

FossilOrigin-Name: 28348f2ada98c616241a51aecb70b63e87e6ddbb

3 files changed, 17 insertions, 15 deletions

diff --git a/src/pager.c b/src/pager.c
index 78cb78ab2..5803b2927 100644
--- a/src/pager.c
+++ b/src/pager.c
@@ -4799,7 +4799,7 @@ int sqlite3PagerOpen(
 
 /* Verify that the database file has not be deleted or renamed out from
 ** under the pager.  Return SQLITE_OK if the database is still were it ought
-** to be on disk.  Return non-zero (SQLITE_IOERR_NODB or some other error
+** to be on disk.  Return non-zero (SQLITE_READONLY_DBMOVED or some other error
 ** code from sqlite3OsAccess()) if the database has gone missing.
 */
 static int databaseIsUnmoved(Pager *pPager){
@@ -4814,7 +4814,7 @@ static int databaseIsUnmoved(Pager *pPager){
   dc = sqlite3OsDeviceCharacteristics(pPager->fd);
   if( (dc&fixedFlags)==fixedFlags ) return SQLITE_OK;
   rc = sqlite3OsAccess(pPager->pVfs, pPager->zFilename, SQLITE_ACCESS_EXISTS, &x);
-  if( rc==SQLITE_OK && !x ) rc = SQLITE_IOERR_NODB;
+  if( rc==SQLITE_OK && !x ) rc = SQLITE_READONLY_DBMOVED;
   return rc;
 }
 
@@ -4991,10 +4991,6 @@ int sqlite3PagerSharedLock(Pager *pPager){
       goto failed;
     }
 
-    /* Verify that the database is unmoved and undeleted */
-    rc = databaseIsUnmoved(pPager);
-    if( rc ) goto failed;
-
     /* If a journal file exists, and there is no RESERVED lock on the
     ** database file, then it either needs to be played back or deleted.
     */
@@ -5498,13 +5494,19 @@ static int pager_open_journal(Pager *pPager){
             (SQLITE_OPEN_DELETEONCLOSE|SQLITE_OPEN_TEMP_JOURNAL):
             (SQLITE_OPEN_MAIN_JOURNAL)
           );
-  #ifdef SQLITE_ENABLE_ATOMIC_WRITE
-        rc = sqlite3JournalOpen(
-            pVfs, pPager->zJournal, pPager->jfd, flags, jrnlBufferSize(pPager)
-        );
-  #else
-        rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, flags, 0);
-  #endif
+
+        /* Verify that the database still has the same name as it did when
+        ** it was originally opened. */
+        rc = databaseIsUnmoved(pPager);
+        if( rc==SQLITE_OK ){
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
+          rc = sqlite3JournalOpen(
+              pVfs, pPager->zJournal, pPager->jfd, flags, jrnlBufferSize(pPager)
+          );
+#else
+          rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, flags, 0);
+#endif
+        }
       }
       assert( rc!=SQLITE_OK || isOpen(pPager->jfd) );
     }
diff --git a/src/sqlite.h.in b/src/sqlite.h.in
index de6b59b0b..f4692f286 100644
--- a/src/sqlite.h.in
+++ b/src/sqlite.h.in
@@ -475,7 +475,6 @@ int sqlite3_exec(
 #define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
 #define SQLITE_IOERR_GETTEMPPATH       (SQLITE_IOERR | (25<<8))
 #define SQLITE_IOERR_CONVPATH          (SQLITE_IOERR | (26<<8))
-#define SQLITE_IOERR_NODB              (SQLITE_IOERR | (27<<8))
 #define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
 #define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
 #define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
@@ -487,6 +486,7 @@ int sqlite3_exec(
 #define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
 #define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
 #define SQLITE_READONLY_ROLLBACK       (SQLITE_READONLY | (3<<8))
+#define SQLITE_READONLY_DBMOVED        (SQLITE_READONLY | (4<<8))
 #define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
 #define SQLITE_CONSTRAINT_CHECK        (SQLITE_CONSTRAINT | (1<<8))
 #define SQLITE_CONSTRAINT_COMMITHOOK   (SQLITE_CONSTRAINT | (2<<8))
diff --git a/src/test_vfstrace.c b/src/test_vfstrace.c
index 8d56cf894..c1792f116 100644
--- a/src/test_vfstrace.c
+++ b/src/test_vfstrace.c
@@ -262,7 +262,7 @@ static void vfstrace_print_errcode(
     case SQLITE_IOERR_SEEK:         zVal = "SQLITE_IOERR_SEEK";         break;
     case SQLITE_IOERR_GETTEMPPATH:  zVal = "SQLITE_IOERR_GETTEMPPATH";  break;
     case SQLITE_IOERR_CONVPATH:     zVal = "SQLITE_IOERR_CONVPATH";     break;
-    case SQLITE_IOERR_NODB:         zVal = "SQLITE_IOERR_NODB";         break;
+    case SQLITE_READONLY_DBMOVED:   zVal = "SQLITE_READONLY_DBMOVED";   break;
     case SQLITE_LOCKED_SHAREDCACHE: zVal = "SQLITE_LOCKED_SHAREDCACHE"; break;
     case SQLITE_BUSY_RECOVERY:      zVal = "SQLITE_BUSY_RECOVERY";      break;
     case SQLITE_CANTOPEN_NOTEMPDIR: zVal = "SQLITE_CANTOPEN_NOTEMPDIR"; break;