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-rw-r--r--src/backend/access/transam/xlog.c61
-rw-r--r--src/backend/commands/dbcommands.c69
-rw-r--r--src/backend/commands/tablespace.c40
3 files changed, 139 insertions, 31 deletions
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 5f8e5e699ff..b9c130bcccb 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -8038,6 +8038,59 @@ StartupXLOG(void)
}
/*
+ * Verify that, in non-test mode, ./pg_tblspc doesn't contain any real
+ * directories.
+ *
+ * Replay of database creation XLOG records for databases that were later
+ * dropped can create fake directories in pg_tblspc. By the time consistency
+ * is reached these directories should have been removed; here we verify
+ * that this did indeed happen. This is to be called at the point where
+ * consistent state is reached.
+ *
+ * allow_in_place_tablespaces turns the PANIC into a WARNING, which is
+ * useful for testing purposes, and also allows for an escape hatch in case
+ * things go south.
+ */
+static void
+CheckTablespaceDirectory(void)
+{
+ DIR *dir;
+ struct dirent *de;
+
+ dir = AllocateDir("pg_tblspc");
+ while ((de = ReadDir(dir, "pg_tblspc")) != NULL)
+ {
+ char path[MAXPGPATH + 10];
+#ifndef WIN32
+ struct stat st;
+#endif
+
+ /* Skip entries of non-oid names */
+ if (strspn(de->d_name, "0123456789") != strlen(de->d_name))
+ continue;
+
+ snprintf(path, sizeof(path), "pg_tblspc/%s", de->d_name);
+
+#ifndef WIN32
+ if (lstat(path, &st) < 0)
+ ereport(LOG,
+ (errcode_for_file_access(),
+ errmsg("could not stat file \"%s\": %m",
+ path)));
+ else if (!S_ISLNK(st.st_mode))
+#else /* WIN32 */
+ if (!pgwin32_is_junction(path))
+#endif
+ ereport(allow_in_place_tablespaces ? WARNING : PANIC,
+ (errcode(ERRCODE_DATA_CORRUPTED),
+ errmsg("unexpected directory entry \"%s\" found in %s",
+ de->d_name, "pg_tblspc/"),
+ errdetail("All directory entries in pg_tblspc/ should be symbolic links."),
+ errhint("Remove those directories, or set allow_in_place_tablespaces to ON transiently to let recovery complete.")));
+ }
+}
+
+/*
* Checks if recovery has reached a consistent state. When consistency is
* reached and we have a valid starting standby snapshot, tell postmaster
* that it can start accepting read-only connections.
@@ -8107,6 +8160,14 @@ CheckRecoveryConsistency(void)
*/
XLogCheckInvalidPages();
+ /*
+ * Check that pg_tblspc doesn't contain any real directories. Replay
+ * of Database/CREATE_* records may have created ficticious tablespace
+ * directories that should have been removed by the time consistency
+ * was reached.
+ */
+ CheckTablespaceDirectory();
+
reachedConsistency = true;
ereport(LOG,
(errmsg("consistent recovery state reached at %X/%X",
diff --git a/src/backend/commands/dbcommands.c b/src/backend/commands/dbcommands.c
index f27c3fe8c1c..abe524f1121 100644
--- a/src/backend/commands/dbcommands.c
+++ b/src/backend/commands/dbcommands.c
@@ -46,6 +46,7 @@
#include "commands/defrem.h"
#include "commands/seclabel.h"
#include "commands/tablespace.h"
+#include "common/file_perm.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "pgstat.h"
@@ -2170,6 +2171,45 @@ get_database_name(Oid dbid)
}
/*
+ * recovery_create_dbdir()
+ *
+ * During recovery, there's a case where we validly need to recover a missing
+ * tablespace directory so that recovery can continue. This happens when
+ * recovery wants to create a database but the holding tablespace has been
+ * removed before the server stopped. Since we expect that the directory will
+ * be gone before reaching recovery consistency, and we have no knowledge about
+ * the tablespace other than its OID here, we create a real directory under
+ * pg_tblspc here instead of restoring the symlink.
+ *
+ * If only_tblspc is true, then the requested directory must be in pg_tblspc/
+ */
+static void
+recovery_create_dbdir(char *path, bool only_tblspc)
+{
+ struct stat st;
+
+ Assert(RecoveryInProgress());
+
+ if (stat(path, &st) == 0)
+ return;
+
+ if (only_tblspc && strstr(path, "pg_tblspc/") == NULL)
+ elog(PANIC, "requested to created invalid directory: %s", path);
+
+ if (reachedConsistency && !allow_in_place_tablespaces)
+ ereport(PANIC,
+ errmsg("missing directory \"%s\"", path));
+
+ elog(reachedConsistency ? WARNING : DEBUG1,
+ "creating missing directory: %s", path);
+
+ if (pg_mkdir_p(path, pg_dir_create_mode) != 0)
+ ereport(PANIC,
+ errmsg("could not create missing directory \"%s\": %m", path));
+}
+
+
+/*
* DATABASE resource manager's routines
*/
void
@@ -2185,6 +2225,7 @@ dbase_redo(XLogReaderState *record)
xl_dbase_create_rec *xlrec = (xl_dbase_create_rec *) XLogRecGetData(record);
char *src_path;
char *dst_path;
+ char *parent_path;
struct stat st;
src_path = GetDatabasePath(xlrec->src_db_id, xlrec->src_tablespace_id);
@@ -2205,6 +2246,34 @@ dbase_redo(XLogReaderState *record)
}
/*
+ * If the parent of the target path doesn't exist, create it now. This
+ * enables us to create the target underneath later. Note that if
+ * the database dir is not in a tablespace, the parent will always
+ * exist, so this never runs in that case.
+ */
+ parent_path = pstrdup(dst_path);
+ get_parent_directory(parent_path);
+ if (stat(parent_path, &st) < 0)
+ {
+ if (errno != ENOENT)
+ ereport(FATAL,
+ errmsg("could not stat directory \"%s\": %m",
+ dst_path));
+
+ recovery_create_dbdir(parent_path, true);
+ }
+ pfree(parent_path);
+
+ /*
+ * There's a case where the copy source directory is missing for the
+ * same reason above. Create the emtpy source directory so that
+ * copydir below doesn't fail. The directory will be dropped soon by
+ * recovery.
+ */
+ if (stat(src_path, &st) < 0 && errno == ENOENT)
+ recovery_create_dbdir(src_path, false);
+
+ /*
* Force dirty buffers out to disk, to ensure source database is
* up-to-date for the copy.
*/
diff --git a/src/backend/commands/tablespace.c b/src/backend/commands/tablespace.c
index 52f23e7467a..3c830d15f50 100644
--- a/src/backend/commands/tablespace.c
+++ b/src/backend/commands/tablespace.c
@@ -154,8 +154,6 @@ TablespaceCreateDbspace(Oid spcNode, Oid dbNode, bool isRedo)
/* Directory creation failed? */
if (MakePGDirectory(dir) < 0)
{
- char *parentdir;
-
/* Failure other than not exists or not in WAL replay? */
if (errno != ENOENT || !isRedo)
ereport(ERROR,
@@ -164,36 +162,16 @@ TablespaceCreateDbspace(Oid spcNode, Oid dbNode, bool isRedo)
dir)));
/*
- * Parent directories are missing during WAL replay, so
- * continue by creating simple parent directories rather
- * than a symlink.
+ * During WAL replay, it's conceivable that several levels
+ * of directories are missing if tablespaces are dropped
+ * further ahead of the WAL stream than we're currently
+ * replaying. An easy way forward is to create them as
+ * plain directories and hope they are removed by further
+ * WAL replay if necessary. If this also fails, there is
+ * trouble we cannot get out of, so just report that and
+ * bail out.
*/
-
- /* 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 (MakePGDirectory(parentdir) < 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 (MakePGDirectory(parentdir) < 0 && errno != EEXIST)
- ereport(ERROR,
- (errcode_for_file_access(),
- errmsg("could not create directory \"%s\": %m",
- parentdir)));
- pfree(parentdir);
-
- /* Create database directory */
- if (MakePGDirectory(dir) < 0)
+ if (pg_mkdir_p(dir, pg_dir_create_mode) < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not create directory \"%s\": %m",
generated by cgit v1.2.3 (git 2.25.1) at 2025-08-02 07:12:41 +0000