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authorTom Lane2000-09-23 23:31:24 +0000
committerTom Lane2000-09-23 23:31:24 +0000
commitde3e0183b827b79454dd1fdf8ae822311bcbc532 (patch)
tree975d1705df5507cb84197a4152cc3e3cfb650df7
parentc954088b83eee2b764ddfafb3825f8c69fb8fd21 (diff)
Back-patch fix that allows AllocateFile() to return errno=ENFILE/EMFILE
after we are no longer able to close any more VFDs. This is needed to avoid postmaster crash under out-of-file-descriptors conditions.
-rw-r--r--src/backend/storage/file/fd.c57
1 files changed, 37 insertions, 20 deletions
diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index e3e1ff00e4c..4db92bc7a9a 100644
--- 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 1.56 2000/04/12 17:15:35 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/storage/file/fd.c,v 1.56.2.1 2000/09/23 23:31:24 tgl Exp $
*
* NOTES:
*
@@ -181,7 +181,7 @@ 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);
@@ -347,7 +347,10 @@ LruInsert(File file)
{
while (nfile + numAllocatedFiles >= pg_nofile())
- ReleaseLruFile();
+ {
+ if (! ReleaseLruFile())
+ break;
+ }
/*
* The open could still fail for lack of file descriptors, eg due
@@ -358,9 +361,12 @@ tryAgain:
vfdP->fd = open(vfdP->fileName, vfdP->fileFlags, vfdP->fileMode);
if (vfdP->fd < 0 && (errno == EMFILE || errno == ENFILE))
{
+ int save_errno = errno;
+
errno = 0;
- ReleaseLruFile();
- goto tryAgain;
+ if (ReleaseLruFile())
+ goto tryAgain;
+ errno = save_errno;
}
if (vfdP->fd < 0)
@@ -392,20 +398,22 @@ tryAgain:
return 0;
}
-static void
+static bool
ReleaseLruFile()
{
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 */
}
/*
@@ -612,17 +620,23 @@ fileNameOpenFile(FileName fileName,
vfdP = &VfdCache[file];
while (nfile + numAllocatedFiles >= pg_nofile())
- ReleaseLruFile();
+ {
+ if (! ReleaseLruFile())
+ break;
+ }
tryAgain:
vfdP->fd = open(fileName, fileFlags, fileMode);
if (vfdP->fd < 0 && (errno == EMFILE || errno == ENFILE))
{
+ int save_errno = errno;
+
DO_DB(elog(DEBUG, "fileNameOpenFile: not enough descs, retry, er= %d",
errno));
errno = 0;
- ReleaseLruFile();
- goto tryAgain;
+ if (ReleaseLruFile())
+ goto tryAgain;
+ errno = save_errno;
}
if (vfdP->fd < 0)
@@ -1004,11 +1018,14 @@ TryAgain:
{
if (errno == EMFILE || errno == ENFILE)
{
+ int save_errno = errno;
+
DO_DB(elog(DEBUG, "AllocateFile: not enough descs, retry, er= %d",
errno));
errno = 0;
- ReleaseLruFile();
- goto TryAgain;
+ if (ReleaseLruFile())
+ goto TryAgain;
+ errno = save_errno;
}
}
else