Simplifications to the locking logic in the unix-dotfile VFS.

FossilOrigin-Name: 583813525888c7e106f3e8cb46c1a507006daee6

3 files changed, 41 insertions, 65 deletions

diff --git a/manifest b/manifest
index 9c1ed4589..a4e23dcb0 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\sthe\ssqldiff\sutility\sprogram\sso\sthat\sit\sworks\sfor\sschemas\sthat\shave\ntables\swith\szero-length\scolumn\snames.
-D 2015-11-29T21:46:19.675
+C Simplifications\sto\sthe\slocking\slogic\sin\sthe\sunix-dotfile\sVFS.
+D 2015-11-30T00:05:39.456
 F Makefile.in d828db6afa6c1fa060d01e33e4674408df1942a1
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc e928e68168df69b353300ac87c10105206653a03
@@ -323,7 +323,7 @@ F src/os.c 8fd25588eeba74068d41102d26810e216999b6c8
 F src/os.h 3e57a24e2794a94d3cf2342c6d9a884888cd96bf
 F src/os_common.h abdb9a191a367793268fe553d25bab894e986a0e
 F src/os_setup.h c9d4553b5aaa6f73391448b265b89bed0b890faa
-F src/os_unix.c 951ef130fd491531d03f4ab07ba4ac4df7861364
+F src/os_unix.c d4ca37d4fa3d65d2d553751f147e61276f5e06bf
 F src/os_win.c 386fba30419e8458b13209781c2af5590eab2811
 F src/os_win.h eb7a47aa17b26b77eb97e4823f20a00b8bda12ca
 F src/pager.c f92aacd5216d8815136c9e0190041783c602641a
@@ -1405,7 +1405,7 @@ F tool/vdbe_profile.tcl 246d0da094856d72d2c12efec03250d71639d19f
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 48bd54594752d5be3337f12c72f28d2080cb630b
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P d6e177fd09c83d46adc5b5d36e9a439aa5397450
-R 6d96f803f67943fdc4d03a972304e707
+P 64263ccb8f9835c615242de6e28db24f953422fa
+R dc472c39e1975a0a69aca2b2404edc3d
 U drh
-Z e1ff9fd256204ded8600114936035e27
+Z 57f1db7fea7d09de3a215136ff8d3a37
diff --git a/manifest.uuid b/manifest.uuid
index 8041987da..edbe83548 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-64263ccb8f9835c615242de6e28db24f953422fa
\ No newline at end of file
+583813525888c7e106f3e8cb46c1a507006daee6
\ No newline at end of file
diff --git a/src/os_unix.c b/src/os_unix.c
index 82224e18f..eb20041ed 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -1350,6 +1350,7 @@ static int unixCheckReservedLock(sqlite3_file *id, int *pResOut){
   SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
 
   assert( pFile );
+  assert( pFile->eFileLock<=SHARED_LOCK );
   unixEnterMutex(); /* Because pFile->pInode is shared across threads */
 
   /* Check if a thread in this process holds such a lock */
@@ -1760,9 +1761,7 @@ static int posixUnlock(sqlite3_file *id, int eFileLock, int handleNFSUnlock){
         if( unixFileLock(pFile, &lock)==(-1) ){
           tErrno = errno;
           rc = SQLITE_IOERR_UNLOCK;
-          if( IS_LOCK_ERROR(rc) ){
-            storeLastErrno(pFile, tErrno);
-          }
+          storeLastErrno(pFile, tErrno);
           goto end_unlock;
         }
         lock.l_type = F_RDLCK;
@@ -1784,9 +1783,7 @@ static int posixUnlock(sqlite3_file *id, int eFileLock, int handleNFSUnlock){
         if( unixFileLock(pFile, &lock)==(-1) ){
           tErrno = errno;
           rc = SQLITE_IOERR_UNLOCK;
-          if( IS_LOCK_ERROR(rc) ){
-            storeLastErrno(pFile, tErrno);
-          }
+          storeLastErrno(pFile, tErrno);
           goto end_unlock;
         }
       }else
@@ -2037,17 +2034,7 @@ static int dotlockCheckReservedLock(sqlite3_file *id, int *pResOut) {
   SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
   
   assert( pFile );
-
-  /* Check if a thread in this process holds such a lock */
-  if( pFile->eFileLock>SHARED_LOCK ){
-    /* Either this connection or some other connection in the same process
-    ** holds a lock on the file.  No need to check further. */
-    reserved = 1;
-  }else{
-    /* The lock is held if and only if the lockfile exists */
-    const char *zLockFile = (const char*)pFile->lockingContext;
-    reserved = osAccess(zLockFile, 0)==0;
-  }
+  reserved = osAccess((const char*)pFile->lockingContext, 0)==0;
   OSTRACE(("TEST WR-LOCK %d %d %d (dotlock)\n", pFile->h, rc, reserved));
   *pResOut = reserved;
   return rc;
@@ -2109,7 +2096,7 @@ static int dotlockLock(sqlite3_file *id, int eFileLock) {
       rc = SQLITE_BUSY;
     } else {
       rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
-      if( IS_LOCK_ERROR(rc) ){
+      if( rc!=SQLITE_BUSY ){
         storeLastErrno(pFile, tErrno);
       }
     }
@@ -2156,14 +2143,12 @@ static int dotlockUnlock(sqlite3_file *id, int eFileLock) {
   /* To fully unlock the database, delete the lock file */
   assert( eFileLock==NO_LOCK );
   rc = osRmdir(zLockFile);
-  if( rc<0 && errno==ENOTDIR ) rc = osUnlink(zLockFile);
   if( rc<0 ){
     int tErrno = errno;
-    rc = 0;
-    if( ENOENT != tErrno ){
+    if( tErrno==ENOENT ){
+      rc = SQLITE_OK;
+    }else{
       rc = SQLITE_IOERR_UNLOCK;
-    }
-    if( IS_LOCK_ERROR(rc) ){
       storeLastErrno(pFile, tErrno);
     }
     return rc; 
@@ -2176,14 +2161,11 @@ static int dotlockUnlock(sqlite3_file *id, int eFileLock) {
 ** Close a file.  Make sure the lock has been released before closing.
 */
 static int dotlockClose(sqlite3_file *id) {
-  int rc = SQLITE_OK;
-  if( id ){
-    unixFile *pFile = (unixFile*)id;
-    dotlockUnlock(id, NO_LOCK);
-    sqlite3_free(pFile->lockingContext);
-    rc = closeUnixFile(id);
-  }
-  return rc;
+  unixFile *pFile = (unixFile*)id;
+  assert( id!=0 );
+  dotlockUnlock(id, NO_LOCK);
+  sqlite3_free(pFile->lockingContext);
+  return closeUnixFile(id);
 }
 /****************** End of the dot-file lock implementation *******************
 ******************************************************************************/
@@ -2249,10 +2231,8 @@ static int flockCheckReservedLock(sqlite3_file *id, int *pResOut){
         int tErrno = errno;
         /* unlock failed with an error */
         lrc = SQLITE_IOERR_UNLOCK; 
-        if( IS_LOCK_ERROR(lrc) ){
-          storeLastErrno(pFile, tErrno);
-          rc = lrc;
-        }
+        storeLastErrno(pFile, tErrno);
+        rc = lrc;
       }
     } else {
       int tErrno = errno;
@@ -2385,12 +2365,9 @@ static int flockUnlock(sqlite3_file *id, int eFileLock) {
 ** Close a file.
 */
 static int flockClose(sqlite3_file *id) {
-  int rc = SQLITE_OK;
-  if( id ){
-    flockUnlock(id, NO_LOCK);
-    rc = closeUnixFile(id);
-  }
-  return rc;
+  assert( id!=0 );
+  flockUnlock(id, NO_LOCK);
+  return closeUnixFile(id);
 }
 
 #endif /* SQLITE_ENABLE_LOCKING_STYLE && !OS_VXWORK */
@@ -3015,23 +2992,22 @@ static int afpUnlock(sqlite3_file *id, int eFileLock) {
 */
 static int afpClose(sqlite3_file *id) {
   int rc = SQLITE_OK;
-  if( id ){
-    unixFile *pFile = (unixFile*)id;
-    afpUnlock(id, NO_LOCK);
-    unixEnterMutex();
-    if( pFile->pInode && pFile->pInode->nLock ){
-      /* If there are outstanding locks, do not actually close the file just
-      ** yet because that would clear those locks.  Instead, add the file
-      ** descriptor to pInode->aPending.  It will be automatically closed when
-      ** the last lock is cleared.
-      */
-      setPendingFd(pFile);
-    }
-    releaseInodeInfo(pFile);
-    sqlite3_free(pFile->lockingContext);
-    rc = closeUnixFile(id);
-    unixLeaveMutex();
+  unixFile *pFile = (unixFile*)id;
+  assert( id!=0 );
+  afpUnlock(id, NO_LOCK);
+  unixEnterMutex();
+  if( pFile->pInode && pFile->pInode->nLock ){
+    /* If there are outstanding locks, do not actually close the file just
+    ** yet because that would clear those locks.  Instead, add the file
+    ** descriptor to pInode->aPending.  It will be automatically closed when
+    ** the last lock is cleared.
+    */
+    setPendingFd(pFile);
   }
+  releaseInodeInfo(pFile);
+  sqlite3_free(pFile->lockingContext);
+  rc = closeUnixFile(id);
+  unixLeaveMutex();
   return rc;
 }
 
@@ -7374,7 +7350,7 @@ static int proxyUnlock(sqlite3_file *id, int eFileLock) {
 ** Close a file that uses proxy locks.
 */
 static int proxyClose(sqlite3_file *id) {
-  if( id ){
+  if( ALWAYS(id) ){
     unixFile *pFile = (unixFile*)id;
     proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
     unixFile *lockProxy = pCtx->lockProxy;