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Clean up CREATE DATABASE processing to make it more robust and get rid

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of special case for Windows port.  Put a PG_TRY around most of createdb()
to ensure that we remove copied subdirectories on failure, even if the
failure happens while creating the pg_database row.  (I think this explains
Oliver Siegmar's recent report.)  Having done that, there's no need for
the fragile assumption that copydir() mustn't ereport(ERROR), so simplify
its API.  Eliminate the old code that used system("cp ...") to copy
subdirectories, in favor of using copydir() on all platforms.  This not
only should allow much better error reporting, but allows us to fsync
the created files before trusting that the copy has succeeded.
This commit is contained in:
Tom Lane
2005-08-02 19:02:32 +00:00
parent 0001e98d54
commit 558730ac6b
6 changed files with 283 additions and 287 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
src/Makefile.global.in
View File

@@ -1,5 +1,5 @@
# -*-makefile-*-
# $PostgreSQL: pgsql/src/Makefile.global.in,v 1.218 2005/07/28 03:15:52 tgl Exp $
# $PostgreSQL: pgsql/src/Makefile.global.in,v 1.219 2005/08/02 19:02:31 tgl Exp $
#------------------------------------------------------------------------------
# All PostgreSQL makefiles include this file and use the variables it sets,
@@ -388,11 +388,10 @@ endif
##########################################################################
#
# substitute implementations of C library routines
# substitute implementations of C library routines (see src/port/)
LIBOBJS = @LIBOBJS@ dirmod.o exec.o noblock.o path.o pipe.o pgsleep.o pgstrcasecmp.o sprompt.o thread.o
LIBOBJS = @LIBOBJS@ copydir.o dirmod.o exec.o noblock.o path.o pipe.o pgsleep.o pgstrcasecmp.o sprompt.o thread.o
ifneq (,$(LIBOBJS))
LIBS := -lpgport $(LIBS)
# add location of libpgport.a to LDFLAGS
ifdef PGXS
@@ -400,7 +399,6 @@ override LDFLAGS := -L$(libdir) $(LDFLAGS)
else
override LDFLAGS := -L$(top_builddir)/src/port $(LDFLAGS)
endif
endif
# to make ws2_32.lib the last library, and always link with shfolder,
# so SHGetFolderName isn't picked up from shell32.dll

389
src/backend/commands/dbcommands.c
View File

@@ -15,7 +15,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/dbcommands.c,v 1.168 2005/07/31 17:19:17 tgl Exp $
* $PostgreSQL: pgsql/src/backend/commands/dbcommands.c,v 1.169 2005/08/02 19:02:31 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -79,14 +79,14 @@ createdb(const CreatedbStmt *stmt)
TransactionId src_vacuumxid;
TransactionId src_frozenxid;
Oid src_deftablespace;
Oid dst_deftablespace;
Relation pg_database_rel;
volatile Oid dst_deftablespace;
volatile Relation pg_database_rel = NULL;
HeapTuple tuple;
TupleDesc pg_database_dsc;
Datum new_record[Natts_pg_database];
char new_record_nulls[Natts_pg_database];
Oid dboid;
Oid datdba;
volatile Oid datdba;
ListCell *option;
DefElem *dtablespacename = NULL;
DefElem *downer = NULL;
@@ -96,12 +96,8 @@ createdb(const CreatedbStmt *stmt)
char *dbname = stmt->dbname;
char *dbowner = NULL;
const char *dbtemplate = NULL;
int encoding = -1;
int dbconnlimit = -1;
#ifndef WIN32
char buf[2 * MAXPGPATH + 100];
#endif
volatile int encoding = -1;
volatile int dbconnlimit = -1;
/* don't call this in a transaction block */
PreventTransactionChain((void *) stmt, "CREATE DATABASE");
@@ -363,207 +359,186 @@ createdb(const CreatedbStmt *stmt)
BufferSync();
/*
* Close virtual file descriptors so the kernel has more available for
* the system() calls below.
* Once we start copying subdirectories, we need to be able to clean
* 'em up if we fail. Establish a TRY block to make sure this happens.
* (This is not a 100% solution, because of the possibility of failure
* during transaction commit after we leave this routine, but it should
* handle most scenarios.)
*/
closeAllVfds();
/*
* Iterate through all tablespaces of the template database, and copy
* each one to the new database.
*/
rel = heap_open(TableSpaceRelationId, AccessShareLock);
scan = heap_beginscan(rel, SnapshotNow, 0, NULL);
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
PG_TRY();
{
Oid srctablespace = HeapTupleGetOid(tuple);
Oid dsttablespace;
char *srcpath;
char *dstpath;
struct stat st;
/* No need to copy global tablespace */
if (srctablespace == GLOBALTABLESPACE_OID)
continue;
srcpath = GetDatabasePath(src_dboid, srctablespace);
if (stat(srcpath, &st) < 0 || !S_ISDIR(st.st_mode) ||
directory_is_empty(srcpath))
/*
* Iterate through all tablespaces of the template database,
* and copy each one to the new database.
*/
rel = heap_open(TableSpaceRelationId, AccessShareLock);
scan = heap_beginscan(rel, SnapshotNow, 0, NULL);
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
/* Assume we can ignore it */
pfree(srcpath);
continue;
Oid srctablespace = HeapTupleGetOid(tuple);
Oid dsttablespace;
char *srcpath;
char *dstpath;
struct stat st;
/* No need to copy global tablespace */
if (srctablespace == GLOBALTABLESPACE_OID)
continue;
srcpath = GetDatabasePath(src_dboid, srctablespace);
if (stat(srcpath, &st) < 0 || !S_ISDIR(st.st_mode) ||
directory_is_empty(srcpath))
{
/* Assume we can ignore it */
pfree(srcpath);
continue;
}
if (srctablespace == src_deftablespace)
dsttablespace = dst_deftablespace;
else
dsttablespace = srctablespace;
dstpath = GetDatabasePath(dboid, dsttablespace);
/*
* Copy this subdirectory to the new location
*
* We don't need to copy subdirectories
*/
copydir(srcpath, dstpath, false);
/* Record the filesystem change in XLOG */
{
xl_dbase_create_rec xlrec;
XLogRecData rdata[1];
xlrec.db_id = dboid;
xlrec.tablespace_id = dsttablespace;
xlrec.src_db_id = src_dboid;
xlrec.src_tablespace_id = srctablespace;
rdata[0].data = (char *) &xlrec;
rdata[0].len = sizeof(xl_dbase_create_rec);
rdata[0].buffer = InvalidBuffer;
rdata[0].next = NULL;
(void) XLogInsert(RM_DBASE_ID, XLOG_DBASE_CREATE, rdata);
}
}
if (srctablespace == src_deftablespace)
dsttablespace = dst_deftablespace;
else
dsttablespace = srctablespace;
dstpath = GetDatabasePath(dboid, dsttablespace);
if (stat(dstpath, &st) == 0 || errno != ENOENT)
{
remove_dbtablespaces(dboid);
ereport(ERROR,
(errmsg("could not initialize database directory"),
errdetail("Directory \"%s\" already exists.",
dstpath)));
}
#ifndef WIN32
heap_endscan(scan);
heap_close(rel, AccessShareLock);
/*
* Copy this subdirectory to the new location
*
* XXX use of cp really makes this code pretty grotty, particularly
* with respect to lack of ability to report errors well. Someday
* rewrite to do it for ourselves.
* Now OK to grab exclusive lock on pg_database.
*/
pg_database_rel = heap_open(DatabaseRelationId, ExclusiveLock);
/* We might need to use cp -R one day for portability */
snprintf(buf, sizeof(buf), "cp -r '%s' '%s'",
srcpath, dstpath);
if (system(buf) != 0)
{
remove_dbtablespaces(dboid);
/* Check to see if someone else created same DB name meanwhile. */
if (get_db_info(dbname, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL))
ereport(ERROR,
(errmsg("could not initialize database directory"),
errdetail("Failing system command was: %s", buf),
errhint("Look in the postmaster's stderr log for more information.")));
}
#else /* WIN32 */
if (copydir(srcpath, dstpath) != 0)
{
/* copydir should already have given details of its troubles */
remove_dbtablespaces(dboid);
ereport(ERROR,
(errmsg("could not initialize database directory")));
}
#endif /* WIN32 */
(errcode(ERRCODE_DUPLICATE_DATABASE),
errmsg("database \"%s\" already exists", dbname)));
/* Record the filesystem change in XLOG */
{
xl_dbase_create_rec xlrec;
XLogRecData rdata[1];
/*
* Insert a new tuple into pg_database
*/
pg_database_dsc = RelationGetDescr(pg_database_rel);
xlrec.db_id = dboid;
xlrec.tablespace_id = dsttablespace;
xlrec.src_db_id = src_dboid;
xlrec.src_tablespace_id = srctablespace;
/* Form tuple */
MemSet(new_record, 0, sizeof(new_record));
MemSet(new_record_nulls, ' ', sizeof(new_record_nulls));
rdata[0].data = (char *) &xlrec;
rdata[0].len = sizeof(xl_dbase_create_rec);
rdata[0].buffer = InvalidBuffer;
rdata[0].next = NULL;
new_record[Anum_pg_database_datname - 1] =
DirectFunctionCall1(namein, CStringGetDatum(dbname));
new_record[Anum_pg_database_datdba - 1] = ObjectIdGetDatum(datdba);
new_record[Anum_pg_database_encoding - 1] = Int32GetDatum(encoding);
new_record[Anum_pg_database_datistemplate - 1] = BoolGetDatum(false);
new_record[Anum_pg_database_datallowconn - 1] = BoolGetDatum(true);
new_record[Anum_pg_database_datconnlimit - 1] = Int32GetDatum(dbconnlimit);
new_record[Anum_pg_database_datlastsysoid - 1] = ObjectIdGetDatum(src_lastsysoid);
new_record[Anum_pg_database_datvacuumxid - 1] = TransactionIdGetDatum(src_vacuumxid);
new_record[Anum_pg_database_datfrozenxid - 1] = TransactionIdGetDatum(src_frozenxid);
new_record[Anum_pg_database_dattablespace - 1] = ObjectIdGetDatum(dst_deftablespace);
(void) XLogInsert(RM_DBASE_ID, XLOG_DBASE_CREATE, rdata);
}
/*
* We deliberately set datconfig and datacl to defaults (NULL), rather
* than copying them from the template database. Copying datacl would
* be a bad idea when the owner is not the same as the template's
* owner. It's more debatable whether datconfig should be copied.
*/
new_record_nulls[Anum_pg_database_datconfig - 1] = 'n';
new_record_nulls[Anum_pg_database_datacl - 1] = 'n';
tuple = heap_formtuple(pg_database_dsc, new_record, new_record_nulls);
HeapTupleSetOid(tuple, dboid); /* override heap_insert's OID
* selection */
simple_heap_insert(pg_database_rel, tuple);
/* Update indexes */
CatalogUpdateIndexes(pg_database_rel, tuple);
/* Register owner dependency */
recordDependencyOnOwner(DatabaseRelationId, dboid, datdba);
/* Create pg_shdepend entries for objects within database */
copyTemplateDependencies(src_dboid, dboid);
/*
* We force a checkpoint before committing. This effectively means
* that committed XLOG_DBASE_CREATE operations will never need to be
* replayed (at least not in ordinary crash recovery; we still have
* to make the XLOG entry for the benefit of PITR operations).
* This avoids two nasty scenarios:
*
* #1: When PITR is off, we don't XLOG the contents of newly created
* indexes; therefore the drop-and-recreate-whole-directory behavior
* of DBASE_CREATE replay would lose such indexes.
*
* #2: Since we have to recopy the source database during DBASE_CREATE
* replay, we run the risk of copying changes in it that were committed
* after the original CREATE DATABASE command but before the system
* crash that led to the replay. This is at least unexpected and at
* worst could lead to inconsistencies, eg duplicate table names.
*
* (Both of these were real bugs in releases 8.0 through 8.0.3.)
*
* In PITR replay, the first of these isn't an issue, and the second
* is only a risk if the CREATE DATABASE and subsequent template
* database change both occur while a base backup is being taken.
* There doesn't seem to be much we can do about that except document
* it as a limitation.
*
* Perhaps if we ever implement CREATE DATABASE in a less cheesy
* way, we can avoid this.
*/
RequestCheckpoint(true, false);
/*
* Set flag to update flat database file at commit.
*/
database_file_update_needed();
}
heap_endscan(scan);
heap_close(rel, AccessShareLock);
/*
* Now OK to grab exclusive lock on pg_database.
*/
pg_database_rel = heap_open(DatabaseRelationId, ExclusiveLock);
/* Check to see if someone else created same DB name meanwhile. */
if (get_db_info(dbname, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL))
PG_CATCH();
{
/* Don't hold lock while doing recursive remove */
heap_close(pg_database_rel, ExclusiveLock);
/* Don't hold pg_database lock while doing recursive remove */
if (pg_database_rel != NULL)
heap_close(pg_database_rel, ExclusiveLock);
/* Throw away any successfully copied subdirectories */
remove_dbtablespaces(dboid);
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_DATABASE),
errmsg("database \"%s\" already exists", dbname)));
PG_RE_THROW();
}
/*
* Insert a new tuple into pg_database
*/
pg_database_dsc = RelationGetDescr(pg_database_rel);
/* Form tuple */
MemSet(new_record, 0, sizeof(new_record));
MemSet(new_record_nulls, ' ', sizeof(new_record_nulls));
new_record[Anum_pg_database_datname - 1] =
DirectFunctionCall1(namein, CStringGetDatum(dbname));
new_record[Anum_pg_database_datdba - 1] = ObjectIdGetDatum(datdba);
new_record[Anum_pg_database_encoding - 1] = Int32GetDatum(encoding);
new_record[Anum_pg_database_datistemplate - 1] = BoolGetDatum(false);
new_record[Anum_pg_database_datallowconn - 1] = BoolGetDatum(true);
new_record[Anum_pg_database_datconnlimit - 1] = Int32GetDatum(dbconnlimit);
new_record[Anum_pg_database_datlastsysoid - 1] = ObjectIdGetDatum(src_lastsysoid);
new_record[Anum_pg_database_datvacuumxid - 1] = TransactionIdGetDatum(src_vacuumxid);
new_record[Anum_pg_database_datfrozenxid - 1] = TransactionIdGetDatum(src_frozenxid);
new_record[Anum_pg_database_dattablespace - 1] = ObjectIdGetDatum(dst_deftablespace);
/*
* We deliberately set datconfig and datacl to defaults (NULL), rather
* than copying them from the template database. Copying datacl would
* be a bad idea when the owner is not the same as the template's
* owner. It's more debatable whether datconfig should be copied.
*/
new_record_nulls[Anum_pg_database_datconfig - 1] = 'n';
new_record_nulls[Anum_pg_database_datacl - 1] = 'n';
tuple = heap_formtuple(pg_database_dsc, new_record, new_record_nulls);
HeapTupleSetOid(tuple, dboid); /* override heap_insert's OID
* selection */
simple_heap_insert(pg_database_rel, tuple);
/* Update indexes */
CatalogUpdateIndexes(pg_database_rel, tuple);
/* Register owner dependency */
recordDependencyOnOwner(DatabaseRelationId, dboid, datdba);
/* Create pg_shdepend entries for objects within database */
copyTemplateDependencies(src_dboid, dboid);
PG_END_TRY();
/* Close pg_database, but keep exclusive lock till commit */
/* This has to be outside the PG_TRY */
heap_close(pg_database_rel, NoLock);
/*
* We force a checkpoint before committing. This effectively means
* that committed XLOG_DBASE_CREATE operations will never need to be
* replayed (at least not in ordinary crash recovery; we still have
* to make the XLOG entry for the benefit of PITR operations).
* This avoids two nasty scenarios:
*
* #1: When PITR is off, we don't XLOG the contents of newly created
* indexes; therefore the drop-and-recreate-whole-directory behavior
* of DBASE_CREATE replay would lose such indexes.
*
* #2: Since we have to recopy the source database during DBASE_CREATE
* replay, we run the risk of copying changes in it that were committed
* after the original CREATE DATABASE command but before the system
* crash that led to the replay. This is at least unexpected and at
* worst could lead to inconsistencies, eg duplicate table names.
*
* (Both of these were real bugs in releases 8.0 through 8.0.3.)
*
* In PITR replay, the first of these isn't an issue, and the second
* is only a risk if the CREATE DATABASE and subsequent template
* database change both occur while a base backup is being taken.
* There doesn't seem to be much we can do about that except document
* it as a limitation.
*
* Perhaps if we ever implement CREATE DATABASE in a less cheesy
* way, we can avoid this.
*/
RequestCheckpoint(true, false);
/*
* Set flag to update flat database file at commit.
*/
database_file_update_needed();
}
@@ -1348,10 +1323,6 @@ dbase_redo(XLogRecPtr lsn, XLogRecord *record)
char *dst_path;
struct stat st;
#ifndef WIN32
char buf[2 * MAXPGPATH + 100];
#endif
src_path = GetDatabasePath(xlrec->src_db_id, xlrec->src_tablespace_id);
dst_path = GetDatabasePath(xlrec->db_id, xlrec->tablespace_id);
@@ -1365,8 +1336,8 @@ dbase_redo(XLogRecPtr lsn, XLogRecord *record)
{
if (!rmtree(dst_path, true))
ereport(WARNING,
(errmsg("could not remove database directory \"%s\"",
dst_path)));
(errmsg("could not remove database directory \"%s\"",
dst_path)));
}
/*
@@ -1376,32 +1347,12 @@ dbase_redo(XLogRecPtr lsn, XLogRecord *record)
*/
BufferSync();
#ifndef WIN32
/*
* Copy this subdirectory to the new location
*
* XXX use of cp really makes this code pretty grotty, particularly
* with respect to lack of ability to report errors well. Someday
* rewrite to do it for ourselves.
* We don't need to copy subdirectories
*/
/* We might need to use cp -R one day for portability */
snprintf(buf, sizeof(buf), "cp -r '%s' '%s'",
src_path, dst_path);
if (system(buf) != 0)
ereport(ERROR,
(errmsg("could not initialize database directory"),
errdetail("Failing system command was: %s", buf),
errhint("Look in the postmaster's stderr log for more information.")));
#else /* WIN32 */
if (copydir(src_path, dst_path) != 0)
{
/* copydir should already have given details of its troubles */
ereport(ERROR,
(errmsg("could not initialize database directory")));
}
#endif /* WIN32 */
copydir(src_path, dst_path, false);
}
else if (info == XLOG_DBASE_DROP)
{

6
src/include/port.h
View File

@@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/port.h,v 1.79 2005/07/06 21:40:09 momjian Exp $
* $PostgreSQL: pgsql/src/include/port.h,v 1.80 2005/08/02 19:02:32 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -206,6 +206,8 @@ extern int pgsymlink(const char *oldpath, const char *newpath);
#endif /* defined(WIN32) || defined(__CYGWIN__) */
extern void copydir(char *fromdir, char *todir, bool recurse);
extern bool rmtree(char *path, bool rmtopdir);
#if defined(WIN32) && !defined(__CYGWIN__)
@@ -223,8 +225,6 @@ extern int win32_open(const char *, int,...);
#define pclose(a) _pclose(a)
#endif
extern int copydir(char *fromdir, char *todir);
/* Missing rand functions */
extern long lrand48(void);
extern void srand48(long seed);

156
src/port/copydir.c
View File

@@ -11,84 +11,140 @@
* as a service.
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/port/copydir.c,v 1.11 2005/03/24 02:11:20 tgl Exp $
* $PostgreSQL: pgsql/src/port/copydir.c,v 1.12 2005/08/02 19:02:32 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>
#include "storage/fd.h"
#undef mkdir /* no reason to use that macro because we
* ignore the 2nd arg */
static void copy_file(char *fromfile, char *tofile);
/*
* copydir: copy a directory (we only need to go one level deep)
* copydir: copy a directory
*
* Return 0 on success, nonzero on failure.
*
* NB: do not elog(ERROR) on failure. Return to caller so it can try to
* clean up.
* If recurse is false, subdirectories are ignored. Anything that's not
* a directory or a regular file is ignored.
*/
int
copydir(char *fromdir, char *todir)
void
copydir(char *fromdir, char *todir, bool recurse)
{
DIR *xldir;
struct dirent *xlde;
char fromfl[MAXPGPATH];
char tofl[MAXPGPATH];
char fromfile[MAXPGPATH];
char tofile[MAXPGPATH];
if (mkdir(todir) != 0)
{
ereport(WARNING,
if (mkdir(todir, S_IRUSR | S_IWUSR | S_IXUSR) != 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not create directory \"%s\": %m", todir)));
return -1;
}
xldir = AllocateDir(fromdir);
if (xldir == NULL)
{
ereport(WARNING,
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not open directory \"%s\": %m", fromdir)));
return -1;
}
errno = 0;
while ((xlde = readdir(xldir)) != NULL)
while ((xlde = ReadDir(xldir, fromdir)) != NULL)
{
snprintf(fromfl, MAXPGPATH, "%s/%s", fromdir, xlde->d_name);
snprintf(tofl, MAXPGPATH, "%s/%s", todir, xlde->d_name);
if (CopyFile(fromfl, tofl, TRUE) < 0)
{
ereport(WARNING,
struct stat fst;
if (strcmp(xlde->d_name, ".") == 0 ||
strcmp(xlde->d_name, "..") == 0)
continue;
snprintf(fromfile, MAXPGPATH, "%s/%s", fromdir, xlde->d_name);
snprintf(tofile, MAXPGPATH, "%s/%s", todir, xlde->d_name);
if (stat(fromfile, &fst) < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not copy file \"%s\": %m", fromfl)));
FreeDir(xldir);
return -1;
}
errno = 0;
}
#ifdef WIN32
errmsg("could not stat \"%s\": %m", fromfile)));
/*
* This fix is in mingw cvs (runtime/mingwex/dirent.c rev 1.4), but
* not in released version
*/
if (GetLastError() == ERROR_NO_MORE_FILES)
errno = 0;
#endif
if (errno)
{
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not read directory \"%s\": %m", fromdir)));
FreeDir(xldir);
return -1;
if (fst.st_mode & S_IFDIR)
{
/* recurse to handle subdirectories */
if (recurse)
copydir(fromfile, tofile, true);
}
else if (fst.st_mode & S_IFREG)
copy_file(fromfile, tofile);
}
FreeDir(xldir);
return 0;
}
/*
* copy one file
*/
static void
copy_file(char *fromfile, char *tofile)
{
char buffer[8 * BLCKSZ];
int srcfd;
int dstfd;
int nbytes;
/*
* Open the files
*/
srcfd = BasicOpenFile(fromfile, O_RDONLY | PG_BINARY, 0);
if (srcfd < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not open file \"%s\": %m", fromfile)));
dstfd = BasicOpenFile(tofile, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
S_IRUSR | S_IWUSR);
if (dstfd < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not create file \"%s\": %m", tofile)));
/*
* Do the data copying.
*/
for (;;)
{
nbytes = read(srcfd, buffer, sizeof(buffer));
if (nbytes < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not read file \"%s\": %m", fromfile)));
if (nbytes == 0)
break;
errno = 0;
if ((int) write(dstfd, buffer, nbytes) != nbytes)
{
/* if write didn't set errno, assume problem is no disk space */
if (errno == 0)
errno = ENOSPC;
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not write to file \"%s\": %m", tofile)));
}
}
/*
* Be paranoid here to ensure we catch problems.
*/
if (pg_fsync(dstfd) != 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not fsync file \"%s\": %m", tofile)));
if (close(dstfd))
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not close file \"%s\": %m", tofile)));
close(srcfd);
}