Change ReleaseLruFile() usage so that if we cannot release any more

virtual FDs, we just return the ENFILE/EMFILE error to the caller,
rather than immediate elog().  This allows more robust behavior in
the postmaster, which uses AllocateFile() but does not want elog().

diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index 6a4ecb6..de6ca57 100644 (file)
--- a/src/backend/storage/file/fd.c
+++ b/src/backend/storage/file/fd.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/storage/file/fd.c,v 1.62 2000/07/05 21:10:05 tgl Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/storage/file/fd.c,v 1.63 2000/08/27 21:48:00 tgl Exp $
  *
  * NOTES:
  *
@@ -182,7 +182,7 @@ static void Delete(File file);
 static void LruDelete(File file);
 static void Insert(File file);
 static int     LruInsert(File file);
-static void ReleaseLruFile(void);
+static bool ReleaseLruFile(void);
 static File AllocateVfd(void);
 static void FreeVfd(File file);
 
@@ -230,13 +230,16 @@ tryAgain:
        if (fd >= 0)
                return fd;                              /* success! */
 
-       if ((errno == EMFILE || errno == ENFILE) && nfile > 0)
+       if (errno == EMFILE || errno == ENFILE)
        {
+               int             save_errno = errno;
+
                DO_DB(elog(DEBUG, "BasicOpenFile: not enough descs, retry, er= %d",
                                   errno));
                errno = 0;
-               ReleaseLruFile();
-               goto tryAgain;
+               if (ReleaseLruFile())
+                       goto tryAgain;
+               errno = save_errno;
        }
 
        return -1;                                      /* failure */
@@ -278,7 +281,7 @@ pg_nofile(void)
 #if defined(FDDEBUG)
 
 static void
-_dump_lru()
+_dump_lru(void)
 {
        int                     mru = VfdCache[0].lruLessRecently;
        Vfd                *vfdP = &VfdCache[mru];
@@ -389,7 +392,10 @@ LruInsert(File file)
        if (FileIsNotOpen(file))
        {
                while (nfile + numAllocatedFiles >= pg_nofile())
-                       ReleaseLruFile();
+               {
+                       if (! ReleaseLruFile())
+                               break;
+               }
 
                /*
                 * The open could still fail for lack of file descriptors, eg due
@@ -400,8 +406,7 @@ LruInsert(File file)
                                                                 vfdP->fileMode);
                if (vfdP->fd < 0)
                {
-                       DO_DB(elog(DEBUG, "RE_OPEN FAILED: %d",
-                                          errno));
+                       DO_DB(elog(DEBUG, "RE_OPEN FAILED: %d", errno));
                        return vfdP->fd;
                }
                else
@@ -427,24 +432,26 @@ LruInsert(File file)
        return 0;
 }
 
-static void
-ReleaseLruFile()
+static bool
+ReleaseLruFile(void)
 {
        DO_DB(elog(DEBUG, "ReleaseLruFile. Opened %d", nfile));
 
-       if (nfile <= 0)
-               elog(ERROR, "ReleaseLruFile: No open files available to be closed");
-
-       /*
-        * There are opened files and so there should be at least one used vfd
-        * in the ring.
-        */
-       Assert(VfdCache[0].lruMoreRecently != 0);
-       LruDelete(VfdCache[0].lruMoreRecently);
+       if (nfile > 0)
+       {
+               /*
+                * There are opened files and so there should be at least one used
+                * vfd in the ring.
+                */
+               Assert(VfdCache[0].lruMoreRecently != 0);
+               LruDelete(VfdCache[0].lruMoreRecently);
+               return true;                    /* freed a file */
+       }
+       return false;                           /* no files available to free */
 }
 
 static File
-AllocateVfd()
+AllocateVfd(void)
 {
        Index           i;
        File            file;
@@ -631,7 +638,10 @@ fileNameOpenFile(FileName fileName,
        vfdP = &VfdCache[file];
 
        while (nfile + numAllocatedFiles >= pg_nofile())
-               ReleaseLruFile();
+       {
+               if (! ReleaseLruFile())
+                       break;
+       }
 
        vfdP->fd = BasicOpenFile(fileName, fileFlags, fileMode);
 
@@ -1027,26 +1037,31 @@ AllocateFile(char *name, char *mode)
 {
        FILE       *file;
 
-       DO_DB(elog(DEBUG, "AllocateFile: Allocated %d.", numAllocatedFiles));
+       DO_DB(elog(DEBUG, "AllocateFile: Allocated %d", numAllocatedFiles));
 
        if (numAllocatedFiles >= MAX_ALLOCATED_FILES)
                elog(ERROR, "AllocateFile: too many private FDs demanded");
 
 TryAgain:
-       if ((file = fopen(name, mode)) == NULL)
+       if ((file = fopen(name, mode)) != NULL)
        {
-               if ((errno == EMFILE || errno == ENFILE) && nfile > 0)
-               {
-                       DO_DB(elog(DEBUG, "AllocateFile: not enough descs, retry, er= %d",
-                                          errno));
-                       errno = 0;
-                       ReleaseLruFile();
+               allocatedFiles[numAllocatedFiles++] = file;
+               return file;
+       }
+
+       if (errno == EMFILE || errno == ENFILE)
+       {
+               int             save_errno = errno;
+
+               DO_DB(elog(DEBUG, "AllocateFile: not enough descs, retry, er= %d",
+                                  errno));
+               errno = 0;
+               if (ReleaseLruFile())
                        goto TryAgain;
-               }
+               errno = save_errno;
        }
-       else
-               allocatedFiles[numAllocatedFiles++] = file;
-       return file;
+
+       return NULL;
 }
 
 void
@@ -1054,7 +1069,7 @@ FreeFile(FILE *file)
 {
        int                     i;
 
-       DO_DB(elog(DEBUG, "FreeFile: Allocated %d.", numAllocatedFiles));
+       DO_DB(elog(DEBUG, "FreeFile: Allocated %d", numAllocatedFiles));
 
        /* Remove file from list of allocated files, if it's present */
        for (i = numAllocatedFiles; --i >= 0;)
@@ -1079,7 +1094,7 @@ FreeFile(FILE *file)
  * change in the logical state of the VFDs.
  */
 void
-closeAllVfds()
+closeAllVfds(void)
 {
        Index           i;