/*-------------------------------------------------------------------------
*
* tablespace.c
* Commands to manipulate table spaces
*
* Tablespaces in PostgreSQL are designed to allow users to determine
* where the data file(s) for a given database object reside on the file
* system.
*
* A tablespace represents a directory on the file system. At tablespace
* creation time, the directory must be empty. To simplify things and
* remove the possibility of having file name conflicts, we isolate
* files within a tablespace into database-specific subdirectories.
*
* To support file access via the information given in RelFileNode, we
* maintain a symbolic-link map in $PGDATA/pg_tblspc. The symlinks are
* named by tablespace OIDs and point to the actual tablespace directories.
* There is also a per-cluster version directory in each tablespace.
* Thus the full path to an arbitrary file is
* $PGDATA/pg_tblspc/spcoid/PG_MAJORVER_CATVER/dboid/relfilenode
* e.g.
* $PGDATA/pg_tblspc/20981/PG_9.0_201002161/719849/83292814
*
* There are two tablespaces created at initdb time: pg_global (for shared
* tables) and pg_default (for everything else). For backwards compatibility
* and to remain functional on platforms without symlinks, these tablespaces
* are accessed specially: they are respectively
* $PGDATA/global/relfilenode
* $PGDATA/base/dboid/relfilenode
*
* To allow CREATE DATABASE to give a new database a default tablespace
* that's different from the template database's default, we make the
* provision that a zero in pg_class.reltablespace means the database's
* default tablespace. Without this, CREATE DATABASE would have to go in
* and munge the system catalogs of the new database.
*
*
* Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/commands/tablespace.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <unistd.h>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "access/heapam.h"
#include "access/reloptions.h"
#include "access/htup_details.h"
#include "access/sysattr.h"
#include "access/xact.h"
#include "access/xlog.h"
#include "access/xloginsert.h"
#include "catalog/catalog.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/namespace.h"
#include "catalog/objectaccess.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_tablespace.h"
#include "commands/comment.h"
#include "commands/seclabel.h"
#include "commands/tablecmds.h"
#include "commands/tablespace.h"
#include "miscadmin.h"
#include "postmaster/bgwriter.h"
#include "storage/fd.h"
#include "storage/lmgr.h"
#include "storage/standby.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/tqual.h"
/* GUC variables */
char *default_tablespace = NULL;
char *temp_tablespaces = NULL;
static void create_tablespace_directories(const char *location,
const Oid tablespaceoid);
static bool destroy_tablespace_directories(Oid tablespaceoid, bool redo);
/*
* Each database using a table space is isolated into its own name space
* by a subdirectory named for the database OID. On first creation of an
* object in the tablespace, create the subdirectory. If the subdirectory
* already exists, fall through quietly.
*
* isRedo indicates that we are creating an object during WAL replay.
* In this case we will cope with the possibility of the tablespace
* directory not being there either --- this could happen if we are
* replaying an operation on a table in a subsequently-dropped tablespace.
* We handle this by making a directory in the place where the tablespace
* symlink would normally be. This isn't an exact replay of course, but
* it's the best we can do given the available information.
*
* If tablespaces are not supported, we still need it in case we have to
* re-create a database subdirectory (of $PGDATA/base) during WAL replay.
*/
void
TablespaceCreateDbspace(Oid spcNode, Oid dbNode, bool isRedo)
{
struct stat st;
char *dir;
/*
* The global tablespace doesn't have per-database subdirectories, so
* nothing to do for it.
*/
if (spcNode == GLOBALTABLESPACE_OID)
return;
Assert(OidIsValid(spcNode));
Assert(OidIsValid(dbNode));
dir = GetDatabasePath(dbNode, spcNode);
if (stat(dir, &st) < 0)
{
/* Directory does not exist? */
if (errno == ENOENT)
{
/*
* Acquire TablespaceCreateLock to ensure that no DROP TABLESPACE
* or TablespaceCreateDbspace is running concurrently.
*/
LWLockAcquire(TablespaceCreateLock, LW_EXCLUSIVE);
/*
* Recheck to see if someone created the directory while we were
* waiting for lock.
*/
if (stat(dir, &st) == 0 && S_ISDIR(st.st_mode))
{
/* Directory was created */
}
else
{
/* Directory creation failed? */
if (mkdir(dir, S_IRWXU) < 0)
{
char *parentdir;
/* Failure other than not exists or not in WAL replay? */
if (errno != ENOENT || !isRedo)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not create directory \"%s\": %m",
dir)));
/*
* Parent directories are missing during WAL replay, so
* continue by creating simple parent directories rather
* than a symlink.
*/
/* create two parents up if not exist */
parentdir = pstrdup(dir);
get_parent_directory(parentdir);
get_parent_directory(parentdir);
/* Can't create parent and it doesn't already exist? */
if (mkdir(parentdir, S_IRWXU) < 0 && errno != EEXIST)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not create directory \"%s\": %m",
parentdir)));
pfree(parentdir);
/* create one parent up if not exist */
parentdir = pstrdup(dir);
get_parent_directory(parentdir);
/* Can't create parent and it doesn't already exist? */
if (mkdir(parentdir, S_IRWXU) < 0 && errno != EEXIST)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not create directory \"%s\": %m",
parentdir)));
pfree(parentdir);
/* Create database directory */
if (mkdir(dir, S_IRWXU) < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not create directory \"%s\": %m",
dir)));
}
}
LWLockRelease(TablespaceCreateLock);
}
else
{
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not stat directory \"%s\": %m", dir)));
}
}
else
{
/* Is it not a directory? */
if (!S_ISDIR(st.st_mode))
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" exists but is not a directory",
dir)));
}
pfree(dir);
}
/*
* Create a table space
*
* Only superusers can create a tablespace. This seems a reasonable restriction
* since we're determining the system layout and, anyway, we probably have
* root if we're doing this kind of activity
*/
Oid
CreateTableSpace(CreateTableSpaceStmt *stmt)
{
#ifdef HAVE_SYMLINK
Relation rel;
Datum values[Natts_pg_tablespace];
bool nulls[Natts_pg_tablespace];
HeapTuple tuple;
Oid tablespaceoid;
char *location;
Oid ownerId;
Datum newOptions;
/* Must be super user */
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied to create tablespace \"%s\"",
stmt->tablespacename),
errhint("Must be superuser to create a tablespace.")));
/* However, the eventual owner of the tablespace need not be */
if (stmt->owner)
ownerId = get_role_oid(stmt->owner, false);
else
ownerId = GetUserId();
/* Unix-ify the offered path, and strip any trailing slashes */
location = pstrdup(stmt->location);
canonicalize_path(location);
/* disallow quotes, else CREATE DATABASE would be at risk */
if (strchr(location, '\''))
ereport(ERROR,
(errcode(ERRCODE_INVALID_NAME),
errmsg("tablespace location cannot contain single quotes")));
/*
* Allowing relative paths seems risky
*
* this also helps us ensure that location is not empty or whitespace
*/
if (!is_absolute_path(location))
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("tablespace location must be an absolute path")));
/*
* Check that location isn't too long. Remember that we're going to append
* 'PG_XXX/<dboid>/<relid>_<fork>.<nnn>'. FYI, we never actually
* reference the whole path here, but mkdir() uses the first two parts.
*/
if (strlen(location) + 1 + strlen(TABLESPACE_VERSION_DIRECTORY) + 1 +
OIDCHARS + 1 + OIDCHARS + 1 + FORKNAMECHARS + 1 + OIDCHARS > MAXPGPATH)
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("tablespace location \"%s\" is too long",
location)));
/*
* Disallow creation of tablespaces named "pg_xxx"; we reserve this
* namespace for system purposes.
*/
if (!allowSystemTableMods && IsReservedName(stmt->tablespacename))
ereport(ERROR,
(errcode(ERRCODE_RESERVED_NAME),
errmsg("unacceptable tablespace name \"%s\"",
stmt->tablespacename),
errdetail("The prefix \"pg_\" is reserved for system tablespaces.")));
/*
* Check that there is no other tablespace by this name. (The unique
* index would catch this anyway, but might as well give a friendlier
* message.)
*/
if (OidIsValid(get_tablespace_oid(stmt->tablespacename, true)))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("tablespace \"%s\" already exists",
stmt->tablespacename)));
/*
* Insert tuple into pg_tablespace. The purpose of doing this first is to
* lock the proposed tablename against other would-be creators. The
* insertion will roll back if we find problems below.
*/
rel = heap_open(TableSpaceRelationId, RowExclusiveLock);
MemSet(nulls, false, sizeof(nulls));
values[Anum_pg_tablespace_spcname - 1] =
DirectFunctionCall1(namein, CStringGetDatum(stmt->tablespacename));
values[Anum_pg_tablespace_spcowner - 1] =
ObjectIdGetDatum(ownerId);
nulls[Anum_pg_tablespace_spcacl - 1] = true;
/* Generate new proposed spcoptions (text array) */
newOptions = transformRelOptions((Datum) 0,
stmt->options,
NULL, NULL, false, false);
(void) tablespace_reloptions(newOptions, true);
if (newOptions != (Datum) 0)
values[Anum_pg_tablespace_spcoptions - 1] = newOptions;
else
nulls[Anum_pg_tablespace_spcoptions - 1] = true;
tuple = heap_form_tuple(rel->rd_att, values, nulls);
tablespaceoid = simple_heap_insert(rel, tuple);
CatalogUpdateIndexes(rel, tuple);
heap_freetuple(tuple);
/* Record dependency on owner */
recordDependencyOnOwner(TableSpaceRelationId, tablespaceoid, ownerId);
/* Post creation hook for new tablespace */
InvokeObjectPostCreateHook(TableSpaceRelationId, tablespaceoid, 0);
create_tablespace_directories(location, tablespaceoid);
/* Record the filesystem change in XLOG */
{
xl_tblspc_create_rec xlrec;
XLogRecData rdata[2];
xlrec.ts_id = tablespaceoid;
rdata[0].data = (char *) &xlrec;
rdata[0].len = offsetof(xl_tblspc_create_rec, ts_path);
rdata[0].buffer = InvalidBuffer;
rdata[0].next = &(rdata[1]);
rdata[1].data = (char *) location;
rdata[1].len = strlen(location) + 1;
rdata[1].buffer = InvalidBuffer;
rdata[1].next = NULL;
(void) XLogInsert(RM_TBLSPC_ID, XLOG_TBLSPC_CREATE, rdata);
}
/*
* Force synchronous commit, to minimize the window between creating the
* symlink on-disk and marking the transaction committed. It's not great
* that there is any window at all, but definitely we don't want to make
* it larger than necessary.
*/
ForceSyncCommit();
pfree(location);
/* We keep the lock on pg_tablespace until commit */
heap_close(rel, NoLock);
#else /* !HAVE_SYMLINK */
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("tablespaces are not supported on this platform")));
#endif /* HAVE_SYMLINK */
return tablespaceoid;
}
/*
* Drop a table space
*
* Be careful to check that the tablespace is empty.
*/
void
DropTableSpace(DropTableSpaceStmt *stmt)
{
#ifdef HAVE_SYMLINK
char *tablespacename = stmt->tablespacename;
HeapScanDesc scandesc;
Relation rel;
HeapTuple tuple;
ScanKeyData entry[1];
Oid tablespaceoid;
/*
* Find the target tuple
*/
rel = heap_open(TableSpaceRelationId, RowExclusiveLock);
ScanKeyInit(&entry[0],
Anum_pg_tablespace_spcname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(tablespacename));
scandesc = heap_beginscan_catalog(rel, 1, entry);
tuple = heap_getnext(scandesc, ForwardScanDirection);
if (!HeapTupleIsValid(tuple))
{
if (!stmt->missing_ok)
{
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("tablespace \"%s\" does not exist",
tablespacename)));
}
else
{
ereport(NOTICE,
(errmsg("tablespace \"%s\" does not exist, skipping",
tablespacename)));
/* XXX I assume I need one or both of these next two calls */
heap_endscan(scandesc);
heap_close(rel, NoLock);
}
return;
}
tablespaceoid = HeapTupleGetOid(tuple);
/* Must be tablespace owner */
if (!pg_tablespace_ownercheck(tablespaceoid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_TABLESPACE,
tablespacename);
/* Disallow drop of the standard tablespaces, even by superuser */
if (tablespaceoid == GLOBALTABLESPACE_OID ||
tablespaceoid == DEFAULTTABLESPACE_OID)
aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_TABLESPACE,
tablespacename);
/* DROP hook for the tablespace being removed */
InvokeObjectDropHook(TableSpaceRelationId, tablespaceoid, 0);
/*
* Remove the pg_tablespace tuple (this will roll back if we fail below)
*/
simple_heap_delete(rel, &tuple->t_self);
heap_endscan(scandesc);
/*
* Remove any comments or security labels on this tablespace.
*/
DeleteSharedComments(tablespaceoid, TableSpaceRelationId);
DeleteSharedSecurityLabel(tablespaceoid, TableSpaceRelationId);
/*
* Remove dependency on owner.
*/
deleteSharedDependencyRecordsFor(TableSpaceRelationId, tablespaceoid, 0);
/*
* Acquire TablespaceCreateLock to ensure that no TablespaceCreateDbspace
* is running concurrently.
*/
LWLockAcquire(TablespaceCreateLock, LW_EXCLUSIVE);
/*
* Try to remove the physical infrastructure.
*/
if (!destroy_tablespace_directories(tablespaceoid, false))
{
/*
* Not all files deleted? However, there can be lingering empty files
* in the directories, left behind by for example DROP TABLE, that
* have been scheduled for deletion at next checkpoint (see comments
* in mdunlink() for details). We could just delete them immediately,
* but we can't tell them apart from important data files that we
* mustn't delete. So instead, we force a checkpoint which will clean
* out any lingering files, and try again.
*
* XXX On Windows, an unlinked file persists in the directory listing
* until no process retains an open handle for the file. The DDL
* commands that schedule files for unlink send invalidation messages
* directing other PostgreSQL processes to close the files. DROP
* TABLESPACE should not give up on the tablespace becoming empty
* until all relevant invalidation processing is complete.
*/
RequestCheckpoint(CHECKPOINT_IMMEDIATE | CHECKPOINT_FORCE | CHECKPOINT_WAIT);
if (!destroy_tablespace_directories(tablespaceoid, false))
{
/* Still not empty, the files must be important then */
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("tablespace \"%s\" is not empty",
tablespacename)));
}
}
/* Record the filesystem change in XLOG */
{
xl_tblspc_drop_rec xlrec;
XLogRecData rdata[1];
xlrec.ts_id = tablespaceoid;
rdata[0].data = (char *) &xlrec;
rdata[0].len = sizeof(xl_tblspc_drop_rec);
rdata[0].buffer = InvalidBuffer;
rdata[0].next = NULL;
(void) XLogInsert(RM_TBLSPC_ID, XLOG_TBLSPC_DROP, rdata);
}
/*
* Note: because we checked that the tablespace was empty, there should be
* no need to worry about flushing shared buffers or free space map
* entries for relations in the tablespace.
*/
/*
* Force synchronous commit, to minimize the window between removing the
* files on-disk and marking the transaction committed. It's not great
* that there is any window at all, but definitely we don't want to make
* it larger than necessary.
*/
ForceSyncCommit();
/*
* Allow TablespaceCreateDbspace again.
*/
LWLockRelease(TablespaceCreateLock);
/* We keep the lock on pg_tablespace until commit */
heap_close(rel, NoLock);
#else /* !HAVE_SYMLINK */
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("tablespaces are not supported on this platform")));
#endif /* HAVE_SYMLINK */
}
/*
* create_tablespace_directories
*
* Attempt to create filesystem infrastructure linking $PGDATA/pg_tblspc/
* to the specified directory
*/
static void
create_tablespace_directories(const char *location, const Oid tablespaceoid)
{
char *linkloc;
char *location_with_version_dir;
struct stat st;
linkloc = psprintf("pg_tblspc/%u", tablespaceoid);
location_with_version_dir = psprintf("%s/%s", location,
TABLESPACE_VERSION_DIRECTORY);
/*
* Attempt to coerce target directory to safe permissions. If this fails,
* it doesn't exist or has the wrong owner.
*/
if (chmod(location, S_IRWXU) != 0)
{
if (errno == ENOENT)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_FILE),
errmsg("directory \"%s\" does not exist", location),
InRecovery ? errhint("Create this directory for the tablespace before "
"restarting the server.") : 0));
else
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not set permissions on directory \"%s\": %m",
location)));
}
if (InRecovery)
{
/*
* Our theory for replaying a CREATE is to forcibly drop the target
* subdirectory if present, and then recreate it. This may be more
* work than needed, but it is simple to implement.
*/
if (stat(location_with_version_dir, &st) == 0 && S_ISDIR(st.st_mode))
{
if (!rmtree(location_with_version_dir, true))
/* If this failed, mkdir() below is going to error. */
ereport(WARNING,
(errmsg("some useless files may be left behind in old database directory \"%s\"",
location_with_version_dir)));
}
}
/*
* The creation of the version directory prevents more than one tablespace
* in a single location.
*/
if (mkdir(location_with_version_dir, S_IRWXU) < 0)
{
if (errno == EEXIST)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("directory \"%s\" already in use as a tablespace",
location_with_version_dir)));
else
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not create directory \"%s\": %m",
location_with_version_dir)));
}
/*
* In recovery, remove old symlink, in case it points to the wrong place.
*
* On Windows, junction points act like directories so we must be able to
* apply rmdir; in general it seems best to make this code work like the
* symlink removal code in destroy_tablespace_directories, except that
* failure to remove is always an ERROR.
*/
if (InRecovery)
{
if (lstat(linkloc, &st) == 0 && S_ISDIR(st.st_mode))
{
if (rmdir(linkloc) < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not remove directory \"%s\": %m",
linkloc)));
}
else
{
if (unlink(linkloc) < 0 && errno != ENOENT)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not remove symbolic link \"%s\": %m",
linkloc)));
}
}
/*
* Create the symlink under PGDATA
*/
if (symlink(location, linkloc) < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not create symbolic link \"%s\": %m",
linkloc)));
pfree(linkloc);
pfree(location_with_version_dir);
}
/*
* destroy_tablespace_directories
*
* Attempt to remove filesystem infrastructure for the tablespace.
*
* 'redo' indicates we are redoing a drop from XLOG; in that case we should
* not throw an ERROR for problems, just LOG them. The worst consequence of
* not removing files here would be failure to release some disk space, which
* does not justify throwing an error that would require manual intervention
* to get the database running again.
*
* Returns TRUE if successful, FALSE if some subdirectory is not empty
*/
static bool
destroy_tablespace_directories(Oid tablespaceoid, bool redo)
{
char *linkloc;
char *linkloc_with_version_dir;
DIR *dirdesc;
struct dirent *de;
char *subfile;
struct stat st;
linkloc_with_version_dir = psprintf("pg_tblspc/%u/%s", tablespaceoid,
TABLESPACE_VERSION_DIRECTORY);
/*
* Check if the tablespace still contains any files. We try to rmdir each
* per-database directory we find in it. rmdir failure implies there are
* still files in that subdirectory, so give up. (We do not have to worry
* about undoing any already completed rmdirs, since the next attempt to
* use the tablespace from that database will simply recreate the
* subdirectory via TablespaceCreateDbspace.)
*
* Since we hold TablespaceCreateLock, no one else should be creating any
* fresh subdirectories in parallel. It is possible that new files are
* being created within subdirectories, though, so the rmdir call could
* fail. Worst consequence is a less friendly error message.
*
* If redo is true then ENOENT is a likely outcome here, and we allow it
* to pass without comment. In normal operation we still allow it, but
* with a warning. This is because even though ProcessUtility disallows
* DROP TABLESPACE in a transaction block, it's possible that a previous
* DROP failed and rolled back after removing the tablespace directories
* and/or symlink. We want to allow a new DROP attempt to succeed at
* removing the catalog entries (and symlink if still present), so we
* should not give a hard error here.
*/
dirdesc = AllocateDir(linkloc_with_version_dir);
if (dirdesc == NULL)
{
if (errno == ENOENT)
{
if (!redo)
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not open directory \"%s\": %m",
linkloc_with_version_dir)));
/* The symlink might still exist, so go try to remove it */
goto remove_symlink;
}
else if (redo)
{
/* in redo, just log other types of error */
ereport(LOG,
(errcode_for_file_access(),
errmsg("could not open directory \"%s\": %m",
linkloc_with_version_dir)));
pfree(linkloc_with_version_dir);
return false;
}
/* else let ReadDir report the error */
}
while ((de = ReadDir(dirdesc, linkloc_with_version_dir)) != NULL)
{
if (strcmp(de->d_name, ".") == 0 ||
strcmp(de->d_name, "..") == 0)
continue;
subfile = psprintf("%s/%s", linkloc_with_version_dir, de->d_name);
/* This check is just to deliver a friendlier error message */
if (!redo && !directory_is_empty(subfile))
{
FreeDir(dirdesc);
pfree(subfile);
pfree(linkloc_with_version_dir);
return false;
}
/* remove empty directory */
if (rmdir(subfile) < 0)
ereport(redo ? LOG : ERROR,
(errcode_for_file_access(),
errmsg("could not remove directory \"%s\": %m",
subfile)));
pfree(subfile);
}
FreeDir(dirdesc);
/* remove version directory */
if (rmdir(linkloc_with_version_dir) < 0)
{
ereport(redo ? LOG : ERROR,
(errcode_for_file_access(),
errmsg("could not remove directory \"%s\": %m",
linkloc_with_version_dir)));
pfree(linkloc_with_version_dir);
return false;
}
/*
* Try to remove the symlink. We must however deal with the possibility
* that it's a directory instead of a symlink --- this could happen during
* WAL replay (see TablespaceCreateDbspace), and it is also the case on
* Windows where junction points lstat() as directories.
*
* Note: in the redo case, we'll return true if this final step fails;
* there's no point in retrying it. Also, ENOENT should provoke no more
* than a warning.
*/
remove_symlink:
linkloc = pstrdup(linkloc_with_version_dir);
get_parent_directory(linkloc);
if (lstat(linkloc, &st) == 0 && S_ISDIR(st.st_mode))
{
if (rmdir(linkloc) < 0)
ereport(redo ? LOG : ERROR,
(errcode_for_file_access(),
errmsg("could not remove directory \"%s\": %m",
linkloc)));
}
else
{
if (unlink(linkloc) < 0)
{
int saved_errno = errno;
ereport(redo ? LOG : (saved_errno == ENOENT ? WARNING : ERROR),
(errcode_for_file_access(),
errmsg("could not remove symbolic link \"%s\": %m",
linkloc)));
}
}
pfree(linkloc_with_version_dir);
pfree(linkloc);
return true;
}
/*
* Check if a directory is empty.
*
* This probably belongs somewhere else, but not sure where...
*/
bool
directory_is_empty(const char *path)
{
DIR *dirdesc;
struct dirent *de;
dirdesc = AllocateDir(path);
while ((de = ReadDir(dirdesc, path)) != NULL)
{
if (strcmp(de->d_name, ".") == 0 ||
strcmp(de->d_name, "..") == 0)
continue;
FreeDir(dirdesc);
return false;
}
FreeDir(dirdesc);
return true;
}
/*
* Rename a tablespace
*/
Oid
RenameTableSpace(const char *oldname, const char *newname)
{
Oid tspId;
Relation rel;
ScanKeyData entry[1];
HeapScanDesc scan;
HeapTuple tup;
HeapTuple newtuple;
Form_pg_tablespace newform;
/* Search pg_tablespace */
rel = heap_open(TableSpaceRelationId, RowExclusiveLock);
ScanKeyInit(&entry[0],
Anum_pg_tablespace_spcname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(oldname));
scan = heap_beginscan_catalog(rel, 1, entry);
tup = heap_getnext(scan, ForwardScanDirection);
if (!HeapTupleIsValid(tup))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("tablespace \"%s\" does not exist",
oldname)));
tspId = HeapTupleGetOid(tup);
newtuple = heap_copytuple(tup);
newform = (Form_pg_tablespace) GETSTRUCT(newtuple);
heap_endscan(scan);
/* Must be owner */
if (!pg_tablespace_ownercheck(HeapTupleGetOid(newtuple), GetUserId()))
aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_TABLESPACE, oldname);
/* Validate new name */
if (!allowSystemTableMods && IsReservedName(newname))
ereport(ERROR,
(errcode(ERRCODE_RESERVED_NAME),
errmsg("unacceptable tablespace name \"%s\"", newname),
errdetail("The prefix \"pg_\" is reserved for system tablespaces.")));
/* Make sure the new name doesn't exist */
ScanKeyInit(&entry[0],
Anum_pg_tablespace_spcname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(newname));
scan = heap_beginscan_catalog(rel, 1, entry);
tup = heap_getnext(scan, ForwardScanDirection);
if (HeapTupleIsValid(tup))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("tablespace \"%s\" already exists",
newname)));
heap_endscan(scan);
/* OK, update the entry */
namestrcpy(&(newform->spcname), newname);
simple_heap_update(rel, &newtuple->t_self, newtuple);
CatalogUpdateIndexes(rel, newtuple);
InvokeObjectPostAlterHook(TableSpaceRelationId, tspId, 0);
heap_close(rel, NoLock);
return tspId;
}
/*
* Alter table space options
*/
Oid
AlterTableSpaceOptions(AlterTableSpaceOptionsStmt *stmt)
{
Relation rel;
ScanKeyData entry[1];
HeapScanDesc scandesc;
HeapTuple tup;
Oid tablespaceoid;
Datum datum;
Datum newOptions;
Datum repl_val[Natts_pg_tablespace];
bool isnull;
bool repl_null[Natts_pg_tablespace];
bool repl_repl[Natts_pg_tablespace];
HeapTuple newtuple;
/* Search pg_tablespace */
rel = heap_open(TableSpaceRelationId, RowExclusiveLock);
ScanKeyInit(&entry[0],
Anum_pg_tablespace_spcname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(stmt->tablespacename));
scandesc = heap_beginscan_catalog(rel, 1, entry);
tup = heap_getnext(scandesc, ForwardScanDirection);
if (!HeapTupleIsValid(tup))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("tablespace \"%s\" does not exist",
stmt->tablespacename)));
tablespaceoid = HeapTupleGetOid(tup);
/* Must be owner of the existing object */
if (!pg_tablespace_ownercheck(HeapTupleGetOid(tup), GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_TABLESPACE,
stmt->tablespacename);
/* Generate new proposed spcoptions (text array) */
datum = heap_getattr(tup, Anum_pg_tablespace_spcoptions,
RelationGetDescr(rel), &isnull);
newOptions = transformRelOptions(isnull ? (Datum) 0 : datum,
stmt->options, NULL, NULL, false,
stmt->isReset);
(void) tablespace_reloptions(newOptions, true);
/* Build new tuple. */
memset(repl_null, false, sizeof(repl_null));
memset(repl_repl, false, sizeof(repl_repl));
if (newOptions != (Datum) 0)
repl_val[Anum_pg_tablespace_spcoptions - 1] = newOptions;
else
repl_null[Anum_pg_tablespace_spcoptions - 1] = true;
repl_repl[Anum_pg_tablespace_spcoptions - 1] = true;
newtuple = heap_modify_tuple(tup, RelationGetDescr(rel), repl_val,
repl_null, repl_repl);
/* Update system catalog. */
simple_heap_update(rel, &newtuple->t_self, newtuple);
CatalogUpdateIndexes(rel, newtuple);
InvokeObjectPostAlterHook(TableSpaceRelationId, HeapTupleGetOid(tup), 0);
heap_freetuple(newtuple);
/* Conclude heap scan. */
heap_endscan(scandesc);
heap_close(rel, NoLock);
return tablespaceoid;
}
/*
* Routines for handling the GUC variable 'default_tablespace'.
*/
/* check_hook: validate new default_tablespace */
bool
check_default_tablespace(char **newval, void **extra, GucSource source)
{
/*
* If we aren't inside a transaction, we cannot do database access so
* cannot verify the name. Must accept the value on faith.
*/
if (IsTransactionState())
{
if (**newval != '\0' &&
!OidIsValid(get_tablespace_oid(*newval, true)))
{
/*
* When source == PGC_S_TEST, don't throw a hard error for a
* nonexistent tablespace, only a NOTICE. See comments in guc.h.
*/
if (source == PGC_S_TEST)
{
ereport(NOTICE,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("tablespace \"%s\" does not exist",
*newval)));
}
else
{
GUC_check_errdetail("Tablespace \"%s\" does not exist.",
*newval);
return false;
}
}
}
return true;
}
/*
* GetDefaultTablespace -- get the OID of the current default tablespace
*
* Temporary objects have different default tablespaces, hence the
* relpersistence parameter must be specified.
*
* May return InvalidOid to indicate "use the database's default tablespace".
*
* Note that caller is expected to check appropriate permissions for any
* result other than InvalidOid.
*
* This exists to hide (and possibly optimize the use of) the
* default_tablespace GUC variable.
*/
Oid
GetDefaultTablespace(char relpersistence)
{
Oid result;
/* The temp-table case is handled elsewhere */
if (relpersistence == RELPERSISTENCE_TEMP)
{
PrepareTempTablespaces();
return GetNextTempTableSpace();
}
/* Fast path for default_tablespace == "" */
if (default_tablespace == NULL || default_tablespace[0] == '\0')
return InvalidOid;
/*
* It is tempting to cache this lookup for more speed, but then we would
* fail to detect the case where the tablespace was dropped since the GUC
* variable was set. Note also that we don't complain if the value fails
* to refer to an existing tablespace; we just silently return InvalidOid,
* causing the new object to be created in the database's tablespace.
*/
result = get_tablespace_oid(default_tablespace, true);
/*
* Allow explicit specification of database's default tablespace in
* default_tablespace without triggering permissions checks.
*/
if (result == MyDatabaseTableSpace)
result = InvalidOid;
return result;
}
/*
* Routines for handling the GUC variable 'temp_tablespaces'.
*/
typedef struct
{
int numSpcs;
Oid tblSpcs[1]; /* VARIABLE LENGTH ARRAY */
} temp_tablespaces_extra;
/* check_hook: validate new temp_tablespaces */
bool
check_temp_tablespaces(char **newval, void **extra, GucSource source)
{
char *rawname;
List *namelist;
/* Need a modifiable copy of string */
rawname = pstrdup(*newval);
/* Parse string into list of identifiers */
if (!SplitIdentifierString(rawname, ',', &namelist))
{
/* syntax error in name list */
GUC_check_errdetail("List syntax is invalid.");
pfree(rawname);
list_free(namelist);
return false;
}
/*
* If we aren't inside a transaction, we cannot do database access so
* cannot verify the individual names. Must accept the list on faith.
* Fortunately, there's then also no need to pass the data to fd.c.
*/
if (IsTransactionState())
{
temp_tablespaces_extra *myextra;
Oid *tblSpcs;
int numSpcs;
ListCell *l;
/* temporary workspace until we are done verifying the list */
tblSpcs = (Oid *) palloc(list_length(namelist) * sizeof(Oid));
numSpcs = 0;
foreach(l, namelist)
{
char *curname = (char *) lfirst(l);
Oid curoid;
AclResult aclresult;
/* Allow an empty string (signifying database default) */
if (curname[0] == '\0')
{
tblSpcs[numSpcs++] = InvalidOid;
continue;
}
/*
* In an interactive SET command, we ereport for bad info. When
* source == PGC_S_TEST, don't throw a hard error for a
* nonexistent tablespace, only a NOTICE. See comments in guc.h.
*/
curoid = get_tablespace_oid(curname, source <= PGC_S_TEST);
if (curoid == InvalidOid)
{
if (source == PGC_S_TEST)
ereport(NOTICE,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("tablespace \"%s\" does not exist",
curname)));
continue;
}
/*
* Allow explicit specification of database's default tablespace
* in temp_tablespaces without triggering permissions checks.
*/
if (curoid == MyDatabaseTableSpace)
{
tblSpcs[numSpcs++] = InvalidOid;
continue;
}
/* Check permissions, similarly complaining only if interactive */
aclresult = pg_tablespace_aclcheck(curoid, GetUserId(),
ACL_CREATE);
if (aclresult != ACLCHECK_OK)
{
if (source >= PGC_S_INTERACTIVE)
aclcheck_error(aclresult, ACL_KIND_TABLESPACE, curname);
continue;
}
tblSpcs[numSpcs++] = curoid;
}
/* Now prepare an "extra" struct for assign_temp_tablespaces */
myextra = malloc(offsetof(temp_tablespaces_extra, tblSpcs) +
numSpcs * sizeof(Oid));
if (!myextra)
return false;
myextra->numSpcs = numSpcs;
memcpy(myextra->tblSpcs, tblSpcs, numSpcs * sizeof(Oid));
*extra = (void *) myextra;
pfree(tblSpcs);
}
pfree(rawname);
list_free(namelist);
return true;
}
/* assign_hook: do extra actions as needed */
void
assign_temp_tablespaces(const char *newval, void *extra)
{
temp_tablespaces_extra *myextra = (temp_tablespaces_extra *) extra;
/*
* If check_temp_tablespaces was executed inside a transaction, then pass
* the list it made to fd.c. Otherwise, clear fd.c's list; we must be
* still outside a transaction, or else restoring during transaction exit,
* and in either case we can just let the next PrepareTempTablespaces call
* make things sane.
*/
if (myextra)
SetTempTablespaces(myextra->tblSpcs, myextra->numSpcs);
else
SetTempTablespaces(NULL, 0);
}
/*
* PrepareTempTablespaces -- prepare to use temp tablespaces
*
* If we have not already done so in the current transaction, parse the
* temp_tablespaces GUC variable and tell fd.c which tablespace(s) to use
* for temp files.
*/
void
PrepareTempTablespaces(void)
{
char *rawname;
List *namelist;
Oid *tblSpcs;
int numSpcs;
ListCell *l;
/* No work if already done in current transaction */
if (TempTablespacesAreSet())
return;
/*
* Can't do catalog access unless within a transaction. This is just a
* safety check in case this function is called by low-level code that
* could conceivably execute outside a transaction. Note that in such a
* scenario, fd.c will fall back to using the current database's default
* tablespace, which should always be OK.
*/
if (!IsTransactionState())
return;
/* Need a modifiable copy of string */
rawname = pstrdup(temp_tablespaces);
/* Parse string into list of identifiers */
if (!SplitIdentifierString(rawname, ',', &namelist))
{
/* syntax error in name list */
SetTempTablespaces(NULL, 0);
pfree(rawname);
list_free(namelist);
return;
}
/* Store tablespace OIDs in an array in TopTransactionContext */
tblSpcs = (Oid *) MemoryContextAlloc(TopTransactionContext,
list_length(namelist) * sizeof(Oid));
numSpcs = 0;
foreach(l, namelist)
{
char *curname = (char *) lfirst(l);
Oid curoid;
AclResult aclresult;
/* Allow an empty string (signifying database default) */
if (curname[0] == '\0')
{
tblSpcs[numSpcs++] = InvalidOid;
continue;
}
/* Else verify that name is a valid tablespace name */
curoid = get_tablespace_oid(curname, true);
if (curoid == InvalidOid)
{
/* Skip any bad list elements */
continue;
}
/*
* Allow explicit specification of database's default tablespace in
* temp_tablespaces without triggering permissions checks.
*/
if (curoid == MyDatabaseTableSpace)
{
tblSpcs[numSpcs++] = InvalidOid;
continue;
}
/* Check permissions similarly */
aclresult = pg_tablespace_aclcheck(curoid, GetUserId(),
ACL_CREATE);
if (aclresult != ACLCHECK_OK)
continue;
tblSpcs[numSpcs++] = curoid;
}
SetTempTablespaces(tblSpcs, numSpcs);
pfree(rawname);
list_free(namelist);
}
/*
* get_tablespace_oid - given a tablespace name, look up the OID
*
* If missing_ok is false, throw an error if tablespace name not found. If
* true, just return InvalidOid.
*/
Oid
get_tablespace_oid(const char *tablespacename, bool missing_ok)
{
Oid result;
Relation rel;
HeapScanDesc scandesc;
HeapTuple tuple;
ScanKeyData entry[1];
/*
* Search pg_tablespace. We use a heapscan here even though there is an
* index on name, on the theory that pg_tablespace will usually have just
* a few entries and so an indexed lookup is a waste of effort.
*/
rel = heap_open(TableSpaceRelationId, AccessShareLock);
ScanKeyInit(&entry[0],
Anum_pg_tablespace_spcname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(tablespacename));
scandesc = heap_beginscan_catalog(rel, 1, entry);
tuple = heap_getnext(scandesc, ForwardScanDirection);
/* We assume that there can be at most one matching tuple */
if (HeapTupleIsValid(tuple))
result = HeapTupleGetOid(tuple);
else
result = InvalidOid;
heap_endscan(scandesc);
heap_close(rel, AccessShareLock);
if (!OidIsValid(result) && !missing_ok)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("tablespace \"%s\" does not exist",
tablespacename)));
return result;
}
/*
* get_tablespace_name - given a tablespace OID, look up the name
*
* Returns a palloc'd string, or NULL if no such tablespace.
*/
char *
get_tablespace_name(Oid spc_oid)
{
char *result;
Relation rel;
HeapScanDesc scandesc;
HeapTuple tuple;
ScanKeyData entry[1];
/*
* Search pg_tablespace. We use a heapscan here even though there is an
* index on oid, on the theory that pg_tablespace will usually have just a
* few entries and so an indexed lookup is a waste of effort.
*/
rel = heap_open(TableSpaceRelationId, AccessShareLock);
ScanKeyInit(&entry[0],
ObjectIdAttributeNumber,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(spc_oid));
scandesc = heap_beginscan_catalog(rel, 1, entry);
tuple = heap_getnext(scandesc, ForwardScanDirection);
/* We assume that there can be at most one matching tuple */
if (HeapTupleIsValid(tuple))
result = pstrdup(NameStr(((Form_pg_tablespace) GETSTRUCT(tuple))->spcname));
else
result = NULL;
heap_endscan(scandesc);
heap_close(rel, AccessShareLock);
return result;
}
/*
* TABLESPACE resource manager's routines
*/
void
tblspc_redo(XLogRecPtr lsn, XLogRecord *record)
{
uint8 info = record->xl_info & ~XLR_INFO_MASK;
/* Backup blocks are not used in tblspc records */
Assert(!(record->xl_info & XLR_BKP_BLOCK_MASK));
if (info == XLOG_TBLSPC_CREATE)
{
xl_tblspc_create_rec *xlrec = (xl_tblspc_create_rec *) XLogRecGetData(record);
char *location = xlrec->ts_path;
create_tablespace_directories(location, xlrec->ts_id);
}
else if (info == XLOG_TBLSPC_DROP)
{
xl_tblspc_drop_rec *xlrec = (xl_tblspc_drop_rec *) XLogRecGetData(record);
/*
* If we issued a WAL record for a drop tablespace it implies that
* there were no files in it at all when the DROP was done. That means
* that no permanent objects can exist in it at this point.
*
* It is possible for standby users to be using this tablespace as a
* location for their temporary files, so if we fail to remove all
* files then do conflict processing and try again, if currently
* enabled.
*
* Other possible reasons for failure include bollixed file
* permissions on a standby server when they were okay on the primary,
* etc etc. There's not much we can do about that, so just remove what
* we can and press on.
*/
if (!destroy_tablespace_directories(xlrec->ts_id, true))
{
ResolveRecoveryConflictWithTablespace(xlrec->ts_id);
/*
* If we did recovery processing then hopefully the backends who
* wrote temp files should have cleaned up and exited by now. So
* retry before complaining. If we fail again, this is just a LOG
* condition, because it's not worth throwing an ERROR for (as
* that would crash the database and require manual intervention
* before we could get past this WAL record on restart).
*/
if (!destroy_tablespace_directories(xlrec->ts_id, true))
ereport(LOG,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("directories for tablespace %u could not be removed",
xlrec->ts_id),
errhint("You can remove the directories manually if necessary.")));
}
}
else
elog(PANIC, "tblspc_redo: unknown op code %u", info);
}