mirror of
https://git.postgresql.org/git/postgresql.git
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3638 lines
96 KiB
C
3638 lines
96 KiB
C
/*-------------------------------------------------------------------------
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*
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* fd.c
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* Virtual file descriptor code.
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*
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* Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* IDENTIFICATION
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* src/backend/storage/file/fd.c
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*
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* NOTES:
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*
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* This code manages a cache of 'virtual' file descriptors (VFDs).
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* The server opens many file descriptors for a variety of reasons,
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* including base tables, scratch files (e.g., sort and hash spool
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* files), and random calls to C library routines like system(3); it
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* is quite easy to exceed system limits on the number of open files a
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* single process can have. (This is around 1024 on many modern
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* operating systems, but may be lower on others.)
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*
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* VFDs are managed as an LRU pool, with actual OS file descriptors
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* being opened and closed as needed. Obviously, if a routine is
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* opened using these interfaces, all subsequent operations must also
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* be through these interfaces (the File type is not a real file
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* descriptor).
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*
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* For this scheme to work, most (if not all) routines throughout the
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* server should use these interfaces instead of calling the C library
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* routines (e.g., open(2) and fopen(3)) themselves. Otherwise, we
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* may find ourselves short of real file descriptors anyway.
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*
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* INTERFACE ROUTINES
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*
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* PathNameOpenFile and OpenTemporaryFile are used to open virtual files.
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* A File opened with OpenTemporaryFile is automatically deleted when the
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* File is closed, either explicitly or implicitly at end of transaction or
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* process exit. PathNameOpenFile is intended for files that are held open
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* for a long time, like relation files. It is the caller's responsibility
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* to close them, there is no automatic mechanism in fd.c for that.
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*
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* PathName(Create|Open|Delete)Temporary(File|Dir) are used to manage
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* temporary files that have names so that they can be shared between
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* backends. Such files are automatically closed and count against the
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* temporary file limit of the backend that creates them, but unlike anonymous
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* files they are not automatically deleted. See sharedfileset.c for a shared
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* ownership mechanism that provides automatic cleanup for shared files when
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* the last of a group of backends detaches.
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*
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* AllocateFile, AllocateDir, OpenPipeStream and OpenTransientFile are
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* wrappers around fopen(3), opendir(3), popen(3) and open(2), respectively.
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* They behave like the corresponding native functions, except that the handle
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* is registered with the current subtransaction, and will be automatically
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* closed at abort. These are intended mainly for short operations like
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* reading a configuration file; there is a limit on the number of files that
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* can be opened using these functions at any one time.
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*
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* Finally, BasicOpenFile is just a thin wrapper around open() that can
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* release file descriptors in use by the virtual file descriptors if
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* necessary. There is no automatic cleanup of file descriptors returned by
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* BasicOpenFile, it is solely the caller's responsibility to close the file
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* descriptor by calling close(2).
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*
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* If a non-virtual file descriptor needs to be held open for any length of
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* time, report it to fd.c by calling AcquireExternalFD or ReserveExternalFD
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* (and eventually ReleaseExternalFD), so that we can take it into account
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* while deciding how many VFDs can be open. This applies to FDs obtained
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* with BasicOpenFile as well as those obtained without use of any fd.c API.
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include <sys/file.h>
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#include <sys/param.h>
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#include <sys/stat.h>
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#ifndef WIN32
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#include <sys/mman.h>
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#endif
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#include <limits.h>
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#include <unistd.h>
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#include <fcntl.h>
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#ifdef HAVE_SYS_RESOURCE_H
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#include <sys/resource.h> /* for getrlimit */
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#endif
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#include "access/xact.h"
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#include "access/xlog.h"
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#include "catalog/pg_tablespace.h"
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#include "common/file_perm.h"
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#include "common/file_utils.h"
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#include "miscadmin.h"
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#include "pgstat.h"
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#include "portability/mem.h"
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#include "storage/fd.h"
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#include "storage/ipc.h"
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#include "utils/guc.h"
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#include "utils/resowner_private.h"
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/* Define PG_FLUSH_DATA_WORKS if we have an implementation for pg_flush_data */
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#if defined(HAVE_SYNC_FILE_RANGE)
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#define PG_FLUSH_DATA_WORKS 1
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#elif !defined(WIN32) && defined(MS_ASYNC)
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#define PG_FLUSH_DATA_WORKS 1
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#elif defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_DONTNEED)
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#define PG_FLUSH_DATA_WORKS 1
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#endif
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/*
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* We must leave some file descriptors free for system(), the dynamic loader,
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* and other code that tries to open files without consulting fd.c. This
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* is the number left free. (While we try fairly hard to prevent EMFILE
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* errors, there's never any guarantee that we won't get ENFILE due to
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* other processes chewing up FDs. So it's a bad idea to try to open files
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* without consulting fd.c. Nonetheless we cannot control all code.)
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*
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* Because this is just a fixed setting, we are effectively assuming that
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* no such code will leave FDs open over the long term; otherwise the slop
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* is likely to be insufficient. Note in particular that we expect that
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* loading a shared library does not result in any permanent increase in
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* the number of open files. (This appears to be true on most if not
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* all platforms as of Feb 2004.)
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*/
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#define NUM_RESERVED_FDS 10
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/*
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* If we have fewer than this many usable FDs after allowing for the reserved
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* ones, choke. (This value is chosen to work with "ulimit -n 64", but not
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* much less than that. Note that this value ensures numExternalFDs can be
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* at least 16; as of this writing, the contrib/postgres_fdw regression tests
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* will not pass unless that can grow to at least 14.)
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*/
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#define FD_MINFREE 48
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/*
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* A number of platforms allow individual processes to open many more files
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* than they can really support when *many* processes do the same thing.
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* This GUC parameter lets the DBA limit max_safe_fds to something less than
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* what the postmaster's initial probe suggests will work.
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*/
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int max_files_per_process = 1000;
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/*
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* Maximum number of file descriptors to open for operations that fd.c knows
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* about (VFDs, AllocateFile etc, or "external" FDs). This is initialized
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* to a conservative value, and remains that way indefinitely in bootstrap or
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* standalone-backend cases. In normal postmaster operation, the postmaster
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* calls set_max_safe_fds() late in initialization to update the value, and
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* that value is then inherited by forked subprocesses.
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*
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* Note: the value of max_files_per_process is taken into account while
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* setting this variable, and so need not be tested separately.
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*/
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int max_safe_fds = FD_MINFREE; /* default if not changed */
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/* Whether it is safe to continue running after fsync() fails. */
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bool data_sync_retry = false;
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/* Debugging.... */
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#ifdef FDDEBUG
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#define DO_DB(A) \
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do { \
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int _do_db_save_errno = errno; \
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A; \
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errno = _do_db_save_errno; \
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} while (0)
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#else
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#define DO_DB(A) \
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((void) 0)
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#endif
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#define VFD_CLOSED (-1)
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#define FileIsValid(file) \
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((file) > 0 && (file) < (int) SizeVfdCache && VfdCache[file].fileName != NULL)
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#define FileIsNotOpen(file) (VfdCache[file].fd == VFD_CLOSED)
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/* these are the assigned bits in fdstate below: */
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#define FD_DELETE_AT_CLOSE (1 << 0) /* T = delete when closed */
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#define FD_CLOSE_AT_EOXACT (1 << 1) /* T = close at eoXact */
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#define FD_TEMP_FILE_LIMIT (1 << 2) /* T = respect temp_file_limit */
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typedef struct vfd
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{
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int fd; /* current FD, or VFD_CLOSED if none */
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unsigned short fdstate; /* bitflags for VFD's state */
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ResourceOwner resowner; /* owner, for automatic cleanup */
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File nextFree; /* link to next free VFD, if in freelist */
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File lruMoreRecently; /* doubly linked recency-of-use list */
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File lruLessRecently;
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off_t fileSize; /* current size of file (0 if not temporary) */
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char *fileName; /* name of file, or NULL for unused VFD */
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/* NB: fileName is malloc'd, and must be free'd when closing the VFD */
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int fileFlags; /* open(2) flags for (re)opening the file */
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mode_t fileMode; /* mode to pass to open(2) */
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} Vfd;
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/*
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* Virtual File Descriptor array pointer and size. This grows as
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* needed. 'File' values are indexes into this array.
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* Note that VfdCache[0] is not a usable VFD, just a list header.
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*/
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static Vfd *VfdCache;
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static Size SizeVfdCache = 0;
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/*
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* Number of file descriptors known to be in use by VFD entries.
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*/
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static int nfile = 0;
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/*
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* Flag to tell whether it's worth scanning VfdCache looking for temp files
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* to close
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*/
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static bool have_xact_temporary_files = false;
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/*
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* Tracks the total size of all temporary files. Note: when temp_file_limit
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* is being enforced, this cannot overflow since the limit cannot be more
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* than INT_MAX kilobytes. When not enforcing, it could theoretically
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* overflow, but we don't care.
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*/
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static uint64 temporary_files_size = 0;
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/*
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* List of OS handles opened with AllocateFile, AllocateDir and
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* OpenTransientFile.
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*/
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typedef enum
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{
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AllocateDescFile,
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AllocateDescPipe,
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AllocateDescDir,
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AllocateDescRawFD
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} AllocateDescKind;
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typedef struct
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{
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AllocateDescKind kind;
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SubTransactionId create_subid;
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union
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{
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FILE *file;
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DIR *dir;
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int fd;
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} desc;
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} AllocateDesc;
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static int numAllocatedDescs = 0;
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static int maxAllocatedDescs = 0;
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static AllocateDesc *allocatedDescs = NULL;
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/*
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* Number of open "external" FDs reported to Reserve/ReleaseExternalFD.
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*/
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static int numExternalFDs = 0;
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/*
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* Number of temporary files opened during the current session;
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* this is used in generation of tempfile names.
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*/
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static long tempFileCounter = 0;
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/*
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* Array of OIDs of temp tablespaces. (Some entries may be InvalidOid,
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* indicating that the current database's default tablespace should be used.)
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* When numTempTableSpaces is -1, this has not been set in the current
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* transaction.
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*/
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static Oid *tempTableSpaces = NULL;
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static int numTempTableSpaces = -1;
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static int nextTempTableSpace = 0;
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/*--------------------
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*
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* Private Routines
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*
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* Delete - delete a file from the Lru ring
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* LruDelete - remove a file from the Lru ring and close its FD
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* Insert - put a file at the front of the Lru ring
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* LruInsert - put a file at the front of the Lru ring and open it
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* ReleaseLruFile - Release an fd by closing the last entry in the Lru ring
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* ReleaseLruFiles - Release fd(s) until we're under the max_safe_fds limit
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* AllocateVfd - grab a free (or new) file record (from VfdCache)
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* FreeVfd - free a file record
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*
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* The Least Recently Used ring is a doubly linked list that begins and
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* ends on element zero. Element zero is special -- it doesn't represent
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* a file and its "fd" field always == VFD_CLOSED. Element zero is just an
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* anchor that shows us the beginning/end of the ring.
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* Only VFD elements that are currently really open (have an FD assigned) are
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* in the Lru ring. Elements that are "virtually" open can be recognized
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* by having a non-null fileName field.
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*
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* example:
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*
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* /--less----\ /---------\
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* v \ v \
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* #0 --more---> LeastRecentlyUsed --more-\ \
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* ^\ | |
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* \\less--> MostRecentlyUsedFile <---/ |
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* \more---/ \--less--/
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*
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*--------------------
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*/
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static void Delete(File file);
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static void LruDelete(File file);
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static void Insert(File file);
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static int LruInsert(File file);
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static bool ReleaseLruFile(void);
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static void ReleaseLruFiles(void);
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static File AllocateVfd(void);
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static void FreeVfd(File file);
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static int FileAccess(File file);
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static File OpenTemporaryFileInTablespace(Oid tblspcOid, bool rejectError);
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static bool reserveAllocatedDesc(void);
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static int FreeDesc(AllocateDesc *desc);
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static void AtProcExit_Files(int code, Datum arg);
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static void CleanupTempFiles(bool isCommit, bool isProcExit);
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static void RemovePgTempRelationFiles(const char *tsdirname);
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static void RemovePgTempRelationFilesInDbspace(const char *dbspacedirname);
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static void walkdir(const char *path,
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void (*action) (const char *fname, bool isdir, int elevel),
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bool process_symlinks,
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int elevel);
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#ifdef PG_FLUSH_DATA_WORKS
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static void pre_sync_fname(const char *fname, bool isdir, int elevel);
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#endif
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static void datadir_fsync_fname(const char *fname, bool isdir, int elevel);
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static void unlink_if_exists_fname(const char *fname, bool isdir, int elevel);
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static int fsync_parent_path(const char *fname, int elevel);
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/*
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* pg_fsync --- do fsync with or without writethrough
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*/
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int
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pg_fsync(int fd)
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{
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#if !defined(WIN32) && defined(USE_ASSERT_CHECKING)
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struct stat st;
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/*
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* Some operating system implementations of fsync() have requirements
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* about the file access modes that were used when their file descriptor
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* argument was opened, and these requirements differ depending on whether
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* the file descriptor is for a directory.
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*
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* For any file descriptor that may eventually be handed to fsync(), we
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* should have opened it with access modes that are compatible with
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* fsync() on all supported systems, otherwise the code may not be
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* portable, even if it runs ok on the current system.
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*
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* We assert here that a descriptor for a file was opened with write
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* permissions (either O_RDWR or O_WRONLY) and for a directory without
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* write permissions (O_RDONLY).
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*
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* Ignore any fstat errors and let the follow-up fsync() do its work.
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* Doing this sanity check here counts for the case where fsync() is
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* disabled.
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*/
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if (fstat(fd, &st) == 0)
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{
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int desc_flags = fcntl(fd, F_GETFL);
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/*
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* O_RDONLY is historically 0, so just make sure that for directories
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* no write flags are used.
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*/
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if (S_ISDIR(st.st_mode))
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Assert((desc_flags & (O_RDWR | O_WRONLY)) == 0);
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else
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Assert((desc_flags & (O_RDWR | O_WRONLY)) != 0);
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}
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errno = 0;
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#endif
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/* #if is to skip the sync_method test if there's no need for it */
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#if defined(HAVE_FSYNC_WRITETHROUGH) && !defined(FSYNC_WRITETHROUGH_IS_FSYNC)
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if (sync_method == SYNC_METHOD_FSYNC_WRITETHROUGH)
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return pg_fsync_writethrough(fd);
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else
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#endif
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return pg_fsync_no_writethrough(fd);
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}
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/*
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* pg_fsync_no_writethrough --- same as fsync except does nothing if
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* enableFsync is off
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*/
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int
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pg_fsync_no_writethrough(int fd)
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{
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if (enableFsync)
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return fsync(fd);
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else
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return 0;
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}
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/*
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* pg_fsync_writethrough
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*/
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int
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pg_fsync_writethrough(int fd)
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{
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if (enableFsync)
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{
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#ifdef WIN32
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return _commit(fd);
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#elif defined(F_FULLFSYNC)
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return (fcntl(fd, F_FULLFSYNC, 0) == -1) ? -1 : 0;
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#else
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errno = ENOSYS;
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return -1;
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#endif
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}
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else
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return 0;
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}
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/*
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* pg_fdatasync --- same as fdatasync except does nothing if enableFsync is off
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*
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* Not all platforms have fdatasync; treat as fsync if not available.
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*/
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int
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pg_fdatasync(int fd)
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{
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if (enableFsync)
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{
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#ifdef HAVE_FDATASYNC
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return fdatasync(fd);
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#else
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return fsync(fd);
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#endif
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}
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else
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return 0;
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}
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/*
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* pg_flush_data --- advise OS that the described dirty data should be flushed
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*
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* offset of 0 with nbytes 0 means that the entire file should be flushed
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*/
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void
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pg_flush_data(int fd, off_t offset, off_t nbytes)
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{
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/*
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* Right now file flushing is primarily used to avoid making later
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* fsync()/fdatasync() calls have less impact. Thus don't trigger flushes
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* if fsyncs are disabled - that's a decision we might want to make
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* configurable at some point.
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*/
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if (!enableFsync)
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return;
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|
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/*
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* We compile all alternatives that are supported on the current platform,
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* to find portability problems more easily.
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*/
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#if defined(HAVE_SYNC_FILE_RANGE)
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{
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int rc;
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static bool not_implemented_by_kernel = false;
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if (not_implemented_by_kernel)
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return;
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|
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/*
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* sync_file_range(SYNC_FILE_RANGE_WRITE), currently linux specific,
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* tells the OS that writeback for the specified blocks should be
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* started, but that we don't want to wait for completion. Note that
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* this call might block if too much dirty data exists in the range.
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* This is the preferable method on OSs supporting it, as it works
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* reliably when available (contrast to msync()) and doesn't flush out
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* clean data (like FADV_DONTNEED).
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*/
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rc = sync_file_range(fd, offset, nbytes,
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SYNC_FILE_RANGE_WRITE);
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if (rc != 0)
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{
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int elevel;
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|
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/*
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|
* For systems that don't have an implementation of
|
|
* sync_file_range() such as Windows WSL, generate only one
|
|
* warning and then suppress all further attempts by this process.
|
|
*/
|
|
if (errno == ENOSYS)
|
|
{
|
|
elevel = WARNING;
|
|
not_implemented_by_kernel = true;
|
|
}
|
|
else
|
|
elevel = data_sync_elevel(WARNING);
|
|
|
|
ereport(elevel,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not flush dirty data: %m")));
|
|
}
|
|
|
|
return;
|
|
}
|
|
#endif
|
|
#if !defined(WIN32) && defined(MS_ASYNC)
|
|
{
|
|
void *p;
|
|
static int pagesize = 0;
|
|
|
|
/*
|
|
* On several OSs msync(MS_ASYNC) on a mmap'ed file triggers
|
|
* writeback. On linux it only does so if MS_SYNC is specified, but
|
|
* then it does the writeback synchronously. Luckily all common linux
|
|
* systems have sync_file_range(). This is preferable over
|
|
* FADV_DONTNEED because it doesn't flush out clean data.
|
|
*
|
|
* We map the file (mmap()), tell the kernel to sync back the contents
|
|
* (msync()), and then remove the mapping again (munmap()).
|
|
*/
|
|
|
|
/* mmap() needs actual length if we want to map whole file */
|
|
if (offset == 0 && nbytes == 0)
|
|
{
|
|
nbytes = lseek(fd, 0, SEEK_END);
|
|
if (nbytes < 0)
|
|
{
|
|
ereport(WARNING,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not determine dirty data size: %m")));
|
|
return;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Some platforms reject partial-page mmap() attempts. To deal with
|
|
* that, just truncate the request to a page boundary. If any extra
|
|
* bytes don't get flushed, well, it's only a hint anyway.
|
|
*/
|
|
|
|
/* fetch pagesize only once */
|
|
if (pagesize == 0)
|
|
pagesize = sysconf(_SC_PAGESIZE);
|
|
|
|
/* align length to pagesize, dropping any fractional page */
|
|
if (pagesize > 0)
|
|
nbytes = (nbytes / pagesize) * pagesize;
|
|
|
|
/* fractional-page request is a no-op */
|
|
if (nbytes <= 0)
|
|
return;
|
|
|
|
/*
|
|
* mmap could well fail, particularly on 32-bit platforms where there
|
|
* may simply not be enough address space. If so, silently fall
|
|
* through to the next implementation.
|
|
*/
|
|
if (nbytes <= (off_t) SSIZE_MAX)
|
|
p = mmap(NULL, nbytes, PROT_READ, MAP_SHARED, fd, offset);
|
|
else
|
|
p = MAP_FAILED;
|
|
|
|
if (p != MAP_FAILED)
|
|
{
|
|
int rc;
|
|
|
|
rc = msync(p, (size_t) nbytes, MS_ASYNC);
|
|
if (rc != 0)
|
|
{
|
|
ereport(data_sync_elevel(WARNING),
|
|
(errcode_for_file_access(),
|
|
errmsg("could not flush dirty data: %m")));
|
|
/* NB: need to fall through to munmap()! */
|
|
}
|
|
|
|
rc = munmap(p, (size_t) nbytes);
|
|
if (rc != 0)
|
|
{
|
|
/* FATAL error because mapping would remain */
|
|
ereport(FATAL,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not munmap() while flushing data: %m")));
|
|
}
|
|
|
|
return;
|
|
}
|
|
}
|
|
#endif
|
|
#if defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_DONTNEED)
|
|
{
|
|
int rc;
|
|
|
|
/*
|
|
* Signal the kernel that the passed in range should not be cached
|
|
* anymore. This has the, desired, side effect of writing out dirty
|
|
* data, and the, undesired, side effect of likely discarding useful
|
|
* clean cached blocks. For the latter reason this is the least
|
|
* preferable method.
|
|
*/
|
|
|
|
rc = posix_fadvise(fd, offset, nbytes, POSIX_FADV_DONTNEED);
|
|
|
|
if (rc != 0)
|
|
{
|
|
/* don't error out, this is just a performance optimization */
|
|
ereport(WARNING,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not flush dirty data: %m")));
|
|
}
|
|
|
|
return;
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Truncate a file to a given length by name.
|
|
*/
|
|
int
|
|
pg_truncate(const char *path, off_t length)
|
|
{
|
|
#ifdef WIN32
|
|
int save_errno;
|
|
int ret;
|
|
int fd;
|
|
|
|
fd = OpenTransientFile(path, O_RDWR | PG_BINARY);
|
|
if (fd >= 0)
|
|
{
|
|
ret = ftruncate(fd, 0);
|
|
save_errno = errno;
|
|
CloseTransientFile(fd);
|
|
errno = save_errno;
|
|
}
|
|
else
|
|
ret = -1;
|
|
|
|
return ret;
|
|
#else
|
|
return truncate(path, length);
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* fsync_fname -- fsync a file or directory, handling errors properly
|
|
*
|
|
* Try to fsync a file or directory. When doing the latter, ignore errors that
|
|
* indicate the OS just doesn't allow/require fsyncing directories.
|
|
*/
|
|
void
|
|
fsync_fname(const char *fname, bool isdir)
|
|
{
|
|
fsync_fname_ext(fname, isdir, false, data_sync_elevel(ERROR));
|
|
}
|
|
|
|
/*
|
|
* durable_rename -- rename(2) wrapper, issuing fsyncs required for durability
|
|
*
|
|
* This routine ensures that, after returning, the effect of renaming file
|
|
* persists in case of a crash. A crash while this routine is running will
|
|
* leave you with either the pre-existing or the moved file in place of the
|
|
* new file; no mixed state or truncated files are possible.
|
|
*
|
|
* It does so by using fsync on the old filename and the possibly existing
|
|
* target filename before the rename, and the target file and directory after.
|
|
*
|
|
* Note that rename() cannot be used across arbitrary directories, as they
|
|
* might not be on the same filesystem. Therefore this routine does not
|
|
* support renaming across directories.
|
|
*
|
|
* Log errors with the caller specified severity.
|
|
*
|
|
* Returns 0 if the operation succeeded, -1 otherwise. Note that errno is not
|
|
* valid upon return.
|
|
*/
|
|
int
|
|
durable_rename(const char *oldfile, const char *newfile, int elevel)
|
|
{
|
|
int fd;
|
|
|
|
/*
|
|
* First fsync the old and target path (if it exists), to ensure that they
|
|
* are properly persistent on disk. Syncing the target file is not
|
|
* strictly necessary, but it makes it easier to reason about crashes;
|
|
* because it's then guaranteed that either source or target file exists
|
|
* after a crash.
|
|
*/
|
|
if (fsync_fname_ext(oldfile, false, false, elevel) != 0)
|
|
return -1;
|
|
|
|
fd = OpenTransientFile(newfile, PG_BINARY | O_RDWR);
|
|
if (fd < 0)
|
|
{
|
|
if (errno != ENOENT)
|
|
{
|
|
ereport(elevel,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not open file \"%s\": %m", newfile)));
|
|
return -1;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
if (pg_fsync(fd) != 0)
|
|
{
|
|
int save_errno;
|
|
|
|
/* close file upon error, might not be in transaction context */
|
|
save_errno = errno;
|
|
CloseTransientFile(fd);
|
|
errno = save_errno;
|
|
|
|
ereport(elevel,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not fsync file \"%s\": %m", newfile)));
|
|
return -1;
|
|
}
|
|
|
|
if (CloseTransientFile(fd) != 0)
|
|
{
|
|
ereport(elevel,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not close file \"%s\": %m", newfile)));
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
/* Time to do the real deal... */
|
|
if (rename(oldfile, newfile) < 0)
|
|
{
|
|
ereport(elevel,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not rename file \"%s\" to \"%s\": %m",
|
|
oldfile, newfile)));
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* To guarantee renaming the file is persistent, fsync the file with its
|
|
* new name, and its containing directory.
|
|
*/
|
|
if (fsync_fname_ext(newfile, false, false, elevel) != 0)
|
|
return -1;
|
|
|
|
if (fsync_parent_path(newfile, elevel) != 0)
|
|
return -1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* durable_unlink -- remove a file in a durable manner
|
|
*
|
|
* This routine ensures that, after returning, the effect of removing file
|
|
* persists in case of a crash. A crash while this routine is running will
|
|
* leave the system in no mixed state.
|
|
*
|
|
* It does so by using fsync on the parent directory of the file after the
|
|
* actual removal is done.
|
|
*
|
|
* Log errors with the severity specified by caller.
|
|
*
|
|
* Returns 0 if the operation succeeded, -1 otherwise. Note that errno is not
|
|
* valid upon return.
|
|
*/
|
|
int
|
|
durable_unlink(const char *fname, int elevel)
|
|
{
|
|
if (unlink(fname) < 0)
|
|
{
|
|
ereport(elevel,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not remove file \"%s\": %m",
|
|
fname)));
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* To guarantee that the removal of the file is persistent, fsync its
|
|
* parent directory.
|
|
*/
|
|
if (fsync_parent_path(fname, elevel) != 0)
|
|
return -1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* durable_rename_excl -- rename a file in a durable manner, without
|
|
* overwriting an existing target file
|
|
*
|
|
* Similar to durable_rename(), except that this routine will fail if the
|
|
* target file already exists.
|
|
*
|
|
* Note that a crash in an unfortunate moment can leave you with two links to
|
|
* the target file.
|
|
*
|
|
* Log errors with the caller specified severity.
|
|
*
|
|
* Returns 0 if the operation succeeded, -1 otherwise. Note that errno is not
|
|
* valid upon return.
|
|
*/
|
|
int
|
|
durable_rename_excl(const char *oldfile, const char *newfile, int elevel)
|
|
{
|
|
/*
|
|
* Ensure that, if we crash directly after the rename/link, a file with
|
|
* valid contents is moved into place.
|
|
*/
|
|
if (fsync_fname_ext(oldfile, false, false, elevel) != 0)
|
|
return -1;
|
|
|
|
if (link(oldfile, newfile) < 0)
|
|
{
|
|
ereport(elevel,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not link file \"%s\" to \"%s\": %m",
|
|
oldfile, newfile)));
|
|
return -1;
|
|
}
|
|
unlink(oldfile);
|
|
|
|
/*
|
|
* Make change persistent in case of an OS crash, both the new entry and
|
|
* its parent directory need to be flushed.
|
|
*/
|
|
if (fsync_fname_ext(newfile, false, false, elevel) != 0)
|
|
return -1;
|
|
|
|
/* Same for parent directory */
|
|
if (fsync_parent_path(newfile, elevel) != 0)
|
|
return -1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* InitFileAccess --- initialize this module during backend startup
|
|
*
|
|
* This is called during either normal or standalone backend start.
|
|
* It is *not* called in the postmaster.
|
|
*/
|
|
void
|
|
InitFileAccess(void)
|
|
{
|
|
Assert(SizeVfdCache == 0); /* call me only once */
|
|
|
|
/* initialize cache header entry */
|
|
VfdCache = (Vfd *) malloc(sizeof(Vfd));
|
|
if (VfdCache == NULL)
|
|
ereport(FATAL,
|
|
(errcode(ERRCODE_OUT_OF_MEMORY),
|
|
errmsg("out of memory")));
|
|
|
|
MemSet((char *) &(VfdCache[0]), 0, sizeof(Vfd));
|
|
VfdCache->fd = VFD_CLOSED;
|
|
|
|
SizeVfdCache = 1;
|
|
|
|
/* register proc-exit hook to ensure temp files are dropped at exit */
|
|
on_proc_exit(AtProcExit_Files, 0);
|
|
}
|
|
|
|
/*
|
|
* count_usable_fds --- count how many FDs the system will let us open,
|
|
* and estimate how many are already open.
|
|
*
|
|
* We stop counting if usable_fds reaches max_to_probe. Note: a small
|
|
* value of max_to_probe might result in an underestimate of already_open;
|
|
* we must fill in any "gaps" in the set of used FDs before the calculation
|
|
* of already_open will give the right answer. In practice, max_to_probe
|
|
* of a couple of dozen should be enough to ensure good results.
|
|
*
|
|
* We assume stdin (FD 0) is available for dup'ing
|
|
*/
|
|
static void
|
|
count_usable_fds(int max_to_probe, int *usable_fds, int *already_open)
|
|
{
|
|
int *fd;
|
|
int size;
|
|
int used = 0;
|
|
int highestfd = 0;
|
|
int j;
|
|
|
|
#ifdef HAVE_GETRLIMIT
|
|
struct rlimit rlim;
|
|
int getrlimit_status;
|
|
#endif
|
|
|
|
size = 1024;
|
|
fd = (int *) palloc(size * sizeof(int));
|
|
|
|
#ifdef HAVE_GETRLIMIT
|
|
#ifdef RLIMIT_NOFILE /* most platforms use RLIMIT_NOFILE */
|
|
getrlimit_status = getrlimit(RLIMIT_NOFILE, &rlim);
|
|
#else /* but BSD doesn't ... */
|
|
getrlimit_status = getrlimit(RLIMIT_OFILE, &rlim);
|
|
#endif /* RLIMIT_NOFILE */
|
|
if (getrlimit_status != 0)
|
|
ereport(WARNING, (errmsg("getrlimit failed: %m")));
|
|
#endif /* HAVE_GETRLIMIT */
|
|
|
|
/* dup until failure or probe limit reached */
|
|
for (;;)
|
|
{
|
|
int thisfd;
|
|
|
|
#ifdef HAVE_GETRLIMIT
|
|
|
|
/*
|
|
* don't go beyond RLIMIT_NOFILE; causes irritating kernel logs on
|
|
* some platforms
|
|
*/
|
|
if (getrlimit_status == 0 && highestfd >= rlim.rlim_cur - 1)
|
|
break;
|
|
#endif
|
|
|
|
thisfd = dup(0);
|
|
if (thisfd < 0)
|
|
{
|
|
/* Expect EMFILE or ENFILE, else it's fishy */
|
|
if (errno != EMFILE && errno != ENFILE)
|
|
elog(WARNING, "dup(0) failed after %d successes: %m", used);
|
|
break;
|
|
}
|
|
|
|
if (used >= size)
|
|
{
|
|
size *= 2;
|
|
fd = (int *) repalloc(fd, size * sizeof(int));
|
|
}
|
|
fd[used++] = thisfd;
|
|
|
|
if (highestfd < thisfd)
|
|
highestfd = thisfd;
|
|
|
|
if (used >= max_to_probe)
|
|
break;
|
|
}
|
|
|
|
/* release the files we opened */
|
|
for (j = 0; j < used; j++)
|
|
close(fd[j]);
|
|
|
|
pfree(fd);
|
|
|
|
/*
|
|
* Return results. usable_fds is just the number of successful dups. We
|
|
* assume that the system limit is highestfd+1 (remember 0 is a legal FD
|
|
* number) and so already_open is highestfd+1 - usable_fds.
|
|
*/
|
|
*usable_fds = used;
|
|
*already_open = highestfd + 1 - used;
|
|
}
|
|
|
|
/*
|
|
* set_max_safe_fds
|
|
* Determine number of file descriptors that fd.c is allowed to use
|
|
*/
|
|
void
|
|
set_max_safe_fds(void)
|
|
{
|
|
int usable_fds;
|
|
int already_open;
|
|
|
|
/*----------
|
|
* We want to set max_safe_fds to
|
|
* MIN(usable_fds, max_files_per_process - already_open)
|
|
* less the slop factor for files that are opened without consulting
|
|
* fd.c. This ensures that we won't exceed either max_files_per_process
|
|
* or the experimentally-determined EMFILE limit.
|
|
*----------
|
|
*/
|
|
count_usable_fds(max_files_per_process,
|
|
&usable_fds, &already_open);
|
|
|
|
max_safe_fds = Min(usable_fds, max_files_per_process - already_open);
|
|
|
|
/*
|
|
* Take off the FDs reserved for system() etc.
|
|
*/
|
|
max_safe_fds -= NUM_RESERVED_FDS;
|
|
|
|
/*
|
|
* Make sure we still have enough to get by.
|
|
*/
|
|
if (max_safe_fds < FD_MINFREE)
|
|
ereport(FATAL,
|
|
(errcode(ERRCODE_INSUFFICIENT_RESOURCES),
|
|
errmsg("insufficient file descriptors available to start server process"),
|
|
errdetail("System allows %d, we need at least %d.",
|
|
max_safe_fds + NUM_RESERVED_FDS,
|
|
FD_MINFREE + NUM_RESERVED_FDS)));
|
|
|
|
elog(DEBUG2, "max_safe_fds = %d, usable_fds = %d, already_open = %d",
|
|
max_safe_fds, usable_fds, already_open);
|
|
}
|
|
|
|
/*
|
|
* Open a file with BasicOpenFilePerm() and pass default file mode for the
|
|
* fileMode parameter.
|
|
*/
|
|
int
|
|
BasicOpenFile(const char *fileName, int fileFlags)
|
|
{
|
|
return BasicOpenFilePerm(fileName, fileFlags, pg_file_create_mode);
|
|
}
|
|
|
|
/*
|
|
* BasicOpenFilePerm --- same as open(2) except can free other FDs if needed
|
|
*
|
|
* This is exported for use by places that really want a plain kernel FD,
|
|
* but need to be proof against running out of FDs. Once an FD has been
|
|
* successfully returned, it is the caller's responsibility to ensure that
|
|
* it will not be leaked on ereport()! Most users should *not* call this
|
|
* routine directly, but instead use the VFD abstraction level, which
|
|
* provides protection against descriptor leaks as well as management of
|
|
* files that need to be open for more than a short period of time.
|
|
*
|
|
* Ideally this should be the *only* direct call of open() in the backend.
|
|
* In practice, the postmaster calls open() directly, and there are some
|
|
* direct open() calls done early in backend startup. Those are OK since
|
|
* this module wouldn't have any open files to close at that point anyway.
|
|
*/
|
|
int
|
|
BasicOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode)
|
|
{
|
|
int fd;
|
|
|
|
tryAgain:
|
|
fd = open(fileName, fileFlags, fileMode);
|
|
|
|
if (fd >= 0)
|
|
return fd; /* success! */
|
|
|
|
if (errno == EMFILE || errno == ENFILE)
|
|
{
|
|
int save_errno = errno;
|
|
|
|
ereport(LOG,
|
|
(errcode(ERRCODE_INSUFFICIENT_RESOURCES),
|
|
errmsg("out of file descriptors: %m; release and retry")));
|
|
errno = 0;
|
|
if (ReleaseLruFile())
|
|
goto tryAgain;
|
|
errno = save_errno;
|
|
}
|
|
|
|
return -1; /* failure */
|
|
}
|
|
|
|
/*
|
|
* AcquireExternalFD - attempt to reserve an external file descriptor
|
|
*
|
|
* This should be used by callers that need to hold a file descriptor open
|
|
* over more than a short interval, but cannot use any of the other facilities
|
|
* provided by this module.
|
|
*
|
|
* The difference between this and the underlying ReserveExternalFD function
|
|
* is that this will report failure (by setting errno and returning false)
|
|
* if "too many" external FDs are already reserved. This should be used in
|
|
* any code where the total number of FDs to be reserved is not predictable
|
|
* and small.
|
|
*/
|
|
bool
|
|
AcquireExternalFD(void)
|
|
{
|
|
/*
|
|
* We don't want more than max_safe_fds / 3 FDs to be consumed for
|
|
* "external" FDs.
|
|
*/
|
|
if (numExternalFDs < max_safe_fds / 3)
|
|
{
|
|
ReserveExternalFD();
|
|
return true;
|
|
}
|
|
errno = EMFILE;
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* ReserveExternalFD - report external consumption of a file descriptor
|
|
*
|
|
* This should be used by callers that need to hold a file descriptor open
|
|
* over more than a short interval, but cannot use any of the other facilities
|
|
* provided by this module. This just tracks the use of the FD and closes
|
|
* VFDs if needed to ensure we keep NUM_RESERVED_FDS FDs available.
|
|
*
|
|
* Call this directly only in code where failure to reserve the FD would be
|
|
* fatal; for example, the WAL-writing code does so, since the alternative is
|
|
* session failure. Also, it's very unwise to do so in code that could
|
|
* consume more than one FD per process.
|
|
*
|
|
* Note: as long as everybody plays nice so that NUM_RESERVED_FDS FDs remain
|
|
* available, it doesn't matter too much whether this is called before or
|
|
* after actually opening the FD; but doing so beforehand reduces the risk of
|
|
* an EMFILE failure if not everybody played nice. In any case, it's solely
|
|
* caller's responsibility to keep the external-FD count in sync with reality.
|
|
*/
|
|
void
|
|
ReserveExternalFD(void)
|
|
{
|
|
/*
|
|
* Release VFDs if needed to stay safe. Because we do this before
|
|
* incrementing numExternalFDs, the final state will be as desired, i.e.,
|
|
* nfile + numAllocatedDescs + numExternalFDs <= max_safe_fds.
|
|
*/
|
|
ReleaseLruFiles();
|
|
|
|
numExternalFDs++;
|
|
}
|
|
|
|
/*
|
|
* ReleaseExternalFD - report release of an external file descriptor
|
|
*
|
|
* This is guaranteed not to change errno, so it can be used in failure paths.
|
|
*/
|
|
void
|
|
ReleaseExternalFD(void)
|
|
{
|
|
Assert(numExternalFDs > 0);
|
|
numExternalFDs--;
|
|
}
|
|
|
|
|
|
#if defined(FDDEBUG)
|
|
|
|
static void
|
|
_dump_lru(void)
|
|
{
|
|
int mru = VfdCache[0].lruLessRecently;
|
|
Vfd *vfdP = &VfdCache[mru];
|
|
char buf[2048];
|
|
|
|
snprintf(buf, sizeof(buf), "LRU: MOST %d ", mru);
|
|
while (mru != 0)
|
|
{
|
|
mru = vfdP->lruLessRecently;
|
|
vfdP = &VfdCache[mru];
|
|
snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "%d ", mru);
|
|
}
|
|
snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "LEAST");
|
|
elog(LOG, "%s", buf);
|
|
}
|
|
#endif /* FDDEBUG */
|
|
|
|
static void
|
|
Delete(File file)
|
|
{
|
|
Vfd *vfdP;
|
|
|
|
Assert(file != 0);
|
|
|
|
DO_DB(elog(LOG, "Delete %d (%s)",
|
|
file, VfdCache[file].fileName));
|
|
DO_DB(_dump_lru());
|
|
|
|
vfdP = &VfdCache[file];
|
|
|
|
VfdCache[vfdP->lruLessRecently].lruMoreRecently = vfdP->lruMoreRecently;
|
|
VfdCache[vfdP->lruMoreRecently].lruLessRecently = vfdP->lruLessRecently;
|
|
|
|
DO_DB(_dump_lru());
|
|
}
|
|
|
|
static void
|
|
LruDelete(File file)
|
|
{
|
|
Vfd *vfdP;
|
|
|
|
Assert(file != 0);
|
|
|
|
DO_DB(elog(LOG, "LruDelete %d (%s)",
|
|
file, VfdCache[file].fileName));
|
|
|
|
vfdP = &VfdCache[file];
|
|
|
|
/*
|
|
* Close the file. We aren't expecting this to fail; if it does, better
|
|
* to leak the FD than to mess up our internal state.
|
|
*/
|
|
if (close(vfdP->fd) != 0)
|
|
elog(vfdP->fdstate & FD_TEMP_FILE_LIMIT ? LOG : data_sync_elevel(LOG),
|
|
"could not close file \"%s\": %m", vfdP->fileName);
|
|
vfdP->fd = VFD_CLOSED;
|
|
--nfile;
|
|
|
|
/* delete the vfd record from the LRU ring */
|
|
Delete(file);
|
|
}
|
|
|
|
static void
|
|
Insert(File file)
|
|
{
|
|
Vfd *vfdP;
|
|
|
|
Assert(file != 0);
|
|
|
|
DO_DB(elog(LOG, "Insert %d (%s)",
|
|
file, VfdCache[file].fileName));
|
|
DO_DB(_dump_lru());
|
|
|
|
vfdP = &VfdCache[file];
|
|
|
|
vfdP->lruMoreRecently = 0;
|
|
vfdP->lruLessRecently = VfdCache[0].lruLessRecently;
|
|
VfdCache[0].lruLessRecently = file;
|
|
VfdCache[vfdP->lruLessRecently].lruMoreRecently = file;
|
|
|
|
DO_DB(_dump_lru());
|
|
}
|
|
|
|
/* returns 0 on success, -1 on re-open failure (with errno set) */
|
|
static int
|
|
LruInsert(File file)
|
|
{
|
|
Vfd *vfdP;
|
|
|
|
Assert(file != 0);
|
|
|
|
DO_DB(elog(LOG, "LruInsert %d (%s)",
|
|
file, VfdCache[file].fileName));
|
|
|
|
vfdP = &VfdCache[file];
|
|
|
|
if (FileIsNotOpen(file))
|
|
{
|
|
/* Close excess kernel FDs. */
|
|
ReleaseLruFiles();
|
|
|
|
/*
|
|
* The open could still fail for lack of file descriptors, eg due to
|
|
* overall system file table being full. So, be prepared to release
|
|
* another FD if necessary...
|
|
*/
|
|
vfdP->fd = BasicOpenFilePerm(vfdP->fileName, vfdP->fileFlags,
|
|
vfdP->fileMode);
|
|
if (vfdP->fd < 0)
|
|
{
|
|
DO_DB(elog(LOG, "re-open failed: %m"));
|
|
return -1;
|
|
}
|
|
else
|
|
{
|
|
++nfile;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* put it at the head of the Lru ring
|
|
*/
|
|
|
|
Insert(file);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Release one kernel FD by closing the least-recently-used VFD.
|
|
*/
|
|
static bool
|
|
ReleaseLruFile(void)
|
|
{
|
|
DO_DB(elog(LOG, "ReleaseLruFile. Opened %d", nfile));
|
|
|
|
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 */
|
|
}
|
|
|
|
/*
|
|
* Release kernel FDs as needed to get under the max_safe_fds limit.
|
|
* After calling this, it's OK to try to open another file.
|
|
*/
|
|
static void
|
|
ReleaseLruFiles(void)
|
|
{
|
|
while (nfile + numAllocatedDescs + numExternalFDs >= max_safe_fds)
|
|
{
|
|
if (!ReleaseLruFile())
|
|
break;
|
|
}
|
|
}
|
|
|
|
static File
|
|
AllocateVfd(void)
|
|
{
|
|
Index i;
|
|
File file;
|
|
|
|
DO_DB(elog(LOG, "AllocateVfd. Size %zu", SizeVfdCache));
|
|
|
|
Assert(SizeVfdCache > 0); /* InitFileAccess not called? */
|
|
|
|
if (VfdCache[0].nextFree == 0)
|
|
{
|
|
/*
|
|
* The free list is empty so it is time to increase the size of the
|
|
* array. We choose to double it each time this happens. However,
|
|
* there's not much point in starting *real* small.
|
|
*/
|
|
Size newCacheSize = SizeVfdCache * 2;
|
|
Vfd *newVfdCache;
|
|
|
|
if (newCacheSize < 32)
|
|
newCacheSize = 32;
|
|
|
|
/*
|
|
* Be careful not to clobber VfdCache ptr if realloc fails.
|
|
*/
|
|
newVfdCache = (Vfd *) realloc(VfdCache, sizeof(Vfd) * newCacheSize);
|
|
if (newVfdCache == NULL)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_OUT_OF_MEMORY),
|
|
errmsg("out of memory")));
|
|
VfdCache = newVfdCache;
|
|
|
|
/*
|
|
* Initialize the new entries and link them into the free list.
|
|
*/
|
|
for (i = SizeVfdCache; i < newCacheSize; i++)
|
|
{
|
|
MemSet((char *) &(VfdCache[i]), 0, sizeof(Vfd));
|
|
VfdCache[i].nextFree = i + 1;
|
|
VfdCache[i].fd = VFD_CLOSED;
|
|
}
|
|
VfdCache[newCacheSize - 1].nextFree = 0;
|
|
VfdCache[0].nextFree = SizeVfdCache;
|
|
|
|
/*
|
|
* Record the new size
|
|
*/
|
|
SizeVfdCache = newCacheSize;
|
|
}
|
|
|
|
file = VfdCache[0].nextFree;
|
|
|
|
VfdCache[0].nextFree = VfdCache[file].nextFree;
|
|
|
|
return file;
|
|
}
|
|
|
|
static void
|
|
FreeVfd(File file)
|
|
{
|
|
Vfd *vfdP = &VfdCache[file];
|
|
|
|
DO_DB(elog(LOG, "FreeVfd: %d (%s)",
|
|
file, vfdP->fileName ? vfdP->fileName : ""));
|
|
|
|
if (vfdP->fileName != NULL)
|
|
{
|
|
free(vfdP->fileName);
|
|
vfdP->fileName = NULL;
|
|
}
|
|
vfdP->fdstate = 0x0;
|
|
|
|
vfdP->nextFree = VfdCache[0].nextFree;
|
|
VfdCache[0].nextFree = file;
|
|
}
|
|
|
|
/* returns 0 on success, -1 on re-open failure (with errno set) */
|
|
static int
|
|
FileAccess(File file)
|
|
{
|
|
int returnValue;
|
|
|
|
DO_DB(elog(LOG, "FileAccess %d (%s)",
|
|
file, VfdCache[file].fileName));
|
|
|
|
/*
|
|
* Is the file open? If not, open it and put it at the head of the LRU
|
|
* ring (possibly closing the least recently used file to get an FD).
|
|
*/
|
|
|
|
if (FileIsNotOpen(file))
|
|
{
|
|
returnValue = LruInsert(file);
|
|
if (returnValue != 0)
|
|
return returnValue;
|
|
}
|
|
else if (VfdCache[0].lruLessRecently != file)
|
|
{
|
|
/*
|
|
* We now know that the file is open and that it is not the last one
|
|
* accessed, so we need to move it to the head of the Lru ring.
|
|
*/
|
|
|
|
Delete(file);
|
|
Insert(file);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Called whenever a temporary file is deleted to report its size.
|
|
*/
|
|
static void
|
|
ReportTemporaryFileUsage(const char *path, off_t size)
|
|
{
|
|
pgstat_report_tempfile(size);
|
|
|
|
if (log_temp_files >= 0)
|
|
{
|
|
if ((size / 1024) >= log_temp_files)
|
|
ereport(LOG,
|
|
(errmsg("temporary file: path \"%s\", size %lu",
|
|
path, (unsigned long) size)));
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Called to register a temporary file for automatic close.
|
|
* ResourceOwnerEnlargeFiles(CurrentResourceOwner) must have been called
|
|
* before the file was opened.
|
|
*/
|
|
static void
|
|
RegisterTemporaryFile(File file)
|
|
{
|
|
ResourceOwnerRememberFile(CurrentResourceOwner, file);
|
|
VfdCache[file].resowner = CurrentResourceOwner;
|
|
|
|
/* Backup mechanism for closing at end of xact. */
|
|
VfdCache[file].fdstate |= FD_CLOSE_AT_EOXACT;
|
|
have_xact_temporary_files = true;
|
|
}
|
|
|
|
/*
|
|
* Called when we get a shared invalidation message on some relation.
|
|
*/
|
|
#ifdef NOT_USED
|
|
void
|
|
FileInvalidate(File file)
|
|
{
|
|
Assert(FileIsValid(file));
|
|
if (!FileIsNotOpen(file))
|
|
LruDelete(file);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Open a file with PathNameOpenFilePerm() and pass default file mode for the
|
|
* fileMode parameter.
|
|
*/
|
|
File
|
|
PathNameOpenFile(const char *fileName, int fileFlags)
|
|
{
|
|
return PathNameOpenFilePerm(fileName, fileFlags, pg_file_create_mode);
|
|
}
|
|
|
|
/*
|
|
* open a file in an arbitrary directory
|
|
*
|
|
* NB: if the passed pathname is relative (which it usually is),
|
|
* it will be interpreted relative to the process' working directory
|
|
* (which should always be $PGDATA when this code is running).
|
|
*/
|
|
File
|
|
PathNameOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode)
|
|
{
|
|
char *fnamecopy;
|
|
File file;
|
|
Vfd *vfdP;
|
|
|
|
DO_DB(elog(LOG, "PathNameOpenFilePerm: %s %x %o",
|
|
fileName, fileFlags, fileMode));
|
|
|
|
/*
|
|
* We need a malloc'd copy of the file name; fail cleanly if no room.
|
|
*/
|
|
fnamecopy = strdup(fileName);
|
|
if (fnamecopy == NULL)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_OUT_OF_MEMORY),
|
|
errmsg("out of memory")));
|
|
|
|
file = AllocateVfd();
|
|
vfdP = &VfdCache[file];
|
|
|
|
/* Close excess kernel FDs. */
|
|
ReleaseLruFiles();
|
|
|
|
vfdP->fd = BasicOpenFilePerm(fileName, fileFlags, fileMode);
|
|
|
|
if (vfdP->fd < 0)
|
|
{
|
|
int save_errno = errno;
|
|
|
|
FreeVfd(file);
|
|
free(fnamecopy);
|
|
errno = save_errno;
|
|
return -1;
|
|
}
|
|
++nfile;
|
|
DO_DB(elog(LOG, "PathNameOpenFile: success %d",
|
|
vfdP->fd));
|
|
|
|
vfdP->fileName = fnamecopy;
|
|
/* Saved flags are adjusted to be OK for re-opening file */
|
|
vfdP->fileFlags = fileFlags & ~(O_CREAT | O_TRUNC | O_EXCL);
|
|
vfdP->fileMode = fileMode;
|
|
vfdP->fileSize = 0;
|
|
vfdP->fdstate = 0x0;
|
|
vfdP->resowner = NULL;
|
|
|
|
Insert(file);
|
|
|
|
return file;
|
|
}
|
|
|
|
/*
|
|
* Create directory 'directory'. If necessary, create 'basedir', which must
|
|
* be the directory above it. This is designed for creating the top-level
|
|
* temporary directory on demand before creating a directory underneath it.
|
|
* Do nothing if the directory already exists.
|
|
*
|
|
* Directories created within the top-level temporary directory should begin
|
|
* with PG_TEMP_FILE_PREFIX, so that they can be identified as temporary and
|
|
* deleted at startup by RemovePgTempFiles(). Further subdirectories below
|
|
* that do not need any particular prefix.
|
|
*/
|
|
void
|
|
PathNameCreateTemporaryDir(const char *basedir, const char *directory)
|
|
{
|
|
if (MakePGDirectory(directory) < 0)
|
|
{
|
|
if (errno == EEXIST)
|
|
return;
|
|
|
|
/*
|
|
* Failed. Try to create basedir first in case it's missing. Tolerate
|
|
* EEXIST to close a race against another process following the same
|
|
* algorithm.
|
|
*/
|
|
if (MakePGDirectory(basedir) < 0 && errno != EEXIST)
|
|
ereport(ERROR,
|
|
(errcode_for_file_access(),
|
|
errmsg("cannot create temporary directory \"%s\": %m",
|
|
basedir)));
|
|
|
|
/* Try again. */
|
|
if (MakePGDirectory(directory) < 0 && errno != EEXIST)
|
|
ereport(ERROR,
|
|
(errcode_for_file_access(),
|
|
errmsg("cannot create temporary subdirectory \"%s\": %m",
|
|
directory)));
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Delete a directory and everything in it, if it exists.
|
|
*/
|
|
void
|
|
PathNameDeleteTemporaryDir(const char *dirname)
|
|
{
|
|
struct stat statbuf;
|
|
|
|
/* Silently ignore missing directory. */
|
|
if (stat(dirname, &statbuf) != 0 && errno == ENOENT)
|
|
return;
|
|
|
|
/*
|
|
* Currently, walkdir doesn't offer a way for our passed in function to
|
|
* maintain state. Perhaps it should, so that we could tell the caller
|
|
* whether this operation succeeded or failed. Since this operation is
|
|
* used in a cleanup path, we wouldn't actually behave differently: we'll
|
|
* just log failures.
|
|
*/
|
|
walkdir(dirname, unlink_if_exists_fname, false, LOG);
|
|
}
|
|
|
|
/*
|
|
* Open a temporary file that will disappear when we close it.
|
|
*
|
|
* This routine takes care of generating an appropriate tempfile name.
|
|
* There's no need to pass in fileFlags or fileMode either, since only
|
|
* one setting makes any sense for a temp file.
|
|
*
|
|
* Unless interXact is true, the file is remembered by CurrentResourceOwner
|
|
* to ensure it's closed and deleted when it's no longer needed, typically at
|
|
* the end-of-transaction. In most cases, you don't want temporary files to
|
|
* outlive the transaction that created them, so this should be false -- but
|
|
* if you need "somewhat" temporary storage, this might be useful. In either
|
|
* case, the file is removed when the File is explicitly closed.
|
|
*/
|
|
File
|
|
OpenTemporaryFile(bool interXact)
|
|
{
|
|
File file = 0;
|
|
|
|
/*
|
|
* Make sure the current resource owner has space for this File before we
|
|
* open it, if we'll be registering it below.
|
|
*/
|
|
if (!interXact)
|
|
ResourceOwnerEnlargeFiles(CurrentResourceOwner);
|
|
|
|
/*
|
|
* If some temp tablespace(s) have been given to us, try to use the next
|
|
* one. If a given tablespace can't be found, we silently fall back to
|
|
* the database's default tablespace.
|
|
*
|
|
* BUT: if the temp file is slated to outlive the current transaction,
|
|
* force it into the database's default tablespace, so that it will not
|
|
* pose a threat to possible tablespace drop attempts.
|
|
*/
|
|
if (numTempTableSpaces > 0 && !interXact)
|
|
{
|
|
Oid tblspcOid = GetNextTempTableSpace();
|
|
|
|
if (OidIsValid(tblspcOid))
|
|
file = OpenTemporaryFileInTablespace(tblspcOid, false);
|
|
}
|
|
|
|
/*
|
|
* If not, or if tablespace is bad, create in database's default
|
|
* tablespace. MyDatabaseTableSpace should normally be set before we get
|
|
* here, but just in case it isn't, fall back to pg_default tablespace.
|
|
*/
|
|
if (file <= 0)
|
|
file = OpenTemporaryFileInTablespace(MyDatabaseTableSpace ?
|
|
MyDatabaseTableSpace :
|
|
DEFAULTTABLESPACE_OID,
|
|
true);
|
|
|
|
/* Mark it for deletion at close and temporary file size limit */
|
|
VfdCache[file].fdstate |= FD_DELETE_AT_CLOSE | FD_TEMP_FILE_LIMIT;
|
|
|
|
/* Register it with the current resource owner */
|
|
if (!interXact)
|
|
RegisterTemporaryFile(file);
|
|
|
|
return file;
|
|
}
|
|
|
|
/*
|
|
* Return the path of the temp directory in a given tablespace.
|
|
*/
|
|
void
|
|
TempTablespacePath(char *path, Oid tablespace)
|
|
{
|
|
/*
|
|
* Identify the tempfile directory for this tablespace.
|
|
*
|
|
* If someone tries to specify pg_global, use pg_default instead.
|
|
*/
|
|
if (tablespace == InvalidOid ||
|
|
tablespace == DEFAULTTABLESPACE_OID ||
|
|
tablespace == GLOBALTABLESPACE_OID)
|
|
snprintf(path, MAXPGPATH, "base/%s", PG_TEMP_FILES_DIR);
|
|
else
|
|
{
|
|
/* All other tablespaces are accessed via symlinks */
|
|
snprintf(path, MAXPGPATH, "pg_tblspc/%u/%s/%s",
|
|
tablespace, TABLESPACE_VERSION_DIRECTORY,
|
|
PG_TEMP_FILES_DIR);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Open a temporary file in a specific tablespace.
|
|
* Subroutine for OpenTemporaryFile, which see for details.
|
|
*/
|
|
static File
|
|
OpenTemporaryFileInTablespace(Oid tblspcOid, bool rejectError)
|
|
{
|
|
char tempdirpath[MAXPGPATH];
|
|
char tempfilepath[MAXPGPATH];
|
|
File file;
|
|
|
|
TempTablespacePath(tempdirpath, tblspcOid);
|
|
|
|
/*
|
|
* Generate a tempfile name that should be unique within the current
|
|
* database instance.
|
|
*/
|
|
snprintf(tempfilepath, sizeof(tempfilepath), "%s/%s%d.%ld",
|
|
tempdirpath, PG_TEMP_FILE_PREFIX, MyProcPid, tempFileCounter++);
|
|
|
|
/*
|
|
* Open the file. Note: we don't use O_EXCL, in case there is an orphaned
|
|
* temp file that can be reused.
|
|
*/
|
|
file = PathNameOpenFile(tempfilepath,
|
|
O_RDWR | O_CREAT | O_TRUNC | PG_BINARY);
|
|
if (file <= 0)
|
|
{
|
|
/*
|
|
* We might need to create the tablespace's tempfile directory, if no
|
|
* one has yet done so.
|
|
*
|
|
* Don't check for an error from MakePGDirectory; it could fail if
|
|
* someone else just did the same thing. If it doesn't work then
|
|
* we'll bomb out on the second create attempt, instead.
|
|
*/
|
|
(void) MakePGDirectory(tempdirpath);
|
|
|
|
file = PathNameOpenFile(tempfilepath,
|
|
O_RDWR | O_CREAT | O_TRUNC | PG_BINARY);
|
|
if (file <= 0 && rejectError)
|
|
elog(ERROR, "could not create temporary file \"%s\": %m",
|
|
tempfilepath);
|
|
}
|
|
|
|
return file;
|
|
}
|
|
|
|
|
|
/*
|
|
* Create a new file. The directory containing it must already exist. Files
|
|
* created this way are subject to temp_file_limit and are automatically
|
|
* closed at end of transaction, but are not automatically deleted on close
|
|
* because they are intended to be shared between cooperating backends.
|
|
*
|
|
* If the file is inside the top-level temporary directory, its name should
|
|
* begin with PG_TEMP_FILE_PREFIX so that it can be identified as temporary
|
|
* and deleted at startup by RemovePgTempFiles(). Alternatively, it can be
|
|
* inside a directory created with PathNameCreateTemporaryDir(), in which case
|
|
* the prefix isn't needed.
|
|
*/
|
|
File
|
|
PathNameCreateTemporaryFile(const char *path, bool error_on_failure)
|
|
{
|
|
File file;
|
|
|
|
ResourceOwnerEnlargeFiles(CurrentResourceOwner);
|
|
|
|
/*
|
|
* Open the file. Note: we don't use O_EXCL, in case there is an orphaned
|
|
* temp file that can be reused.
|
|
*/
|
|
file = PathNameOpenFile(path, O_RDWR | O_CREAT | O_TRUNC | PG_BINARY);
|
|
if (file <= 0)
|
|
{
|
|
if (error_on_failure)
|
|
ereport(ERROR,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not create temporary file \"%s\": %m",
|
|
path)));
|
|
else
|
|
return file;
|
|
}
|
|
|
|
/* Mark it for temp_file_limit accounting. */
|
|
VfdCache[file].fdstate |= FD_TEMP_FILE_LIMIT;
|
|
|
|
/* Register it for automatic close. */
|
|
RegisterTemporaryFile(file);
|
|
|
|
return file;
|
|
}
|
|
|
|
/*
|
|
* Open a file that was created with PathNameCreateTemporaryFile, possibly in
|
|
* another backend. Files opened this way don't count against the
|
|
* temp_file_limit of the caller, are automatically closed at the end of the
|
|
* transaction but are not deleted on close.
|
|
*/
|
|
File
|
|
PathNameOpenTemporaryFile(const char *path, int mode)
|
|
{
|
|
File file;
|
|
|
|
ResourceOwnerEnlargeFiles(CurrentResourceOwner);
|
|
|
|
file = PathNameOpenFile(path, mode | PG_BINARY);
|
|
|
|
/* If no such file, then we don't raise an error. */
|
|
if (file <= 0 && errno != ENOENT)
|
|
ereport(ERROR,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not open temporary file \"%s\": %m",
|
|
path)));
|
|
|
|
if (file > 0)
|
|
{
|
|
/* Register it for automatic close. */
|
|
RegisterTemporaryFile(file);
|
|
}
|
|
|
|
return file;
|
|
}
|
|
|
|
/*
|
|
* Delete a file by pathname. Return true if the file existed, false if
|
|
* didn't.
|
|
*/
|
|
bool
|
|
PathNameDeleteTemporaryFile(const char *path, bool error_on_failure)
|
|
{
|
|
struct stat filestats;
|
|
int stat_errno;
|
|
|
|
/* Get the final size for pgstat reporting. */
|
|
if (stat(path, &filestats) != 0)
|
|
stat_errno = errno;
|
|
else
|
|
stat_errno = 0;
|
|
|
|
/*
|
|
* Unlike FileClose's automatic file deletion code, we tolerate
|
|
* non-existence to support BufFileDeleteShared which doesn't know how
|
|
* many segments it has to delete until it runs out.
|
|
*/
|
|
if (stat_errno == ENOENT)
|
|
return false;
|
|
|
|
if (unlink(path) < 0)
|
|
{
|
|
if (errno != ENOENT)
|
|
ereport(error_on_failure ? ERROR : LOG,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not unlink temporary file \"%s\": %m",
|
|
path)));
|
|
return false;
|
|
}
|
|
|
|
if (stat_errno == 0)
|
|
ReportTemporaryFileUsage(path, filestats.st_size);
|
|
else
|
|
{
|
|
errno = stat_errno;
|
|
ereport(LOG,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not stat file \"%s\": %m", path)));
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* close a file when done with it
|
|
*/
|
|
void
|
|
FileClose(File file)
|
|
{
|
|
Vfd *vfdP;
|
|
|
|
Assert(FileIsValid(file));
|
|
|
|
DO_DB(elog(LOG, "FileClose: %d (%s)",
|
|
file, VfdCache[file].fileName));
|
|
|
|
vfdP = &VfdCache[file];
|
|
|
|
if (!FileIsNotOpen(file))
|
|
{
|
|
/* close the file */
|
|
if (close(vfdP->fd) != 0)
|
|
{
|
|
/*
|
|
* We may need to panic on failure to close non-temporary files;
|
|
* see LruDelete.
|
|
*/
|
|
elog(vfdP->fdstate & FD_TEMP_FILE_LIMIT ? LOG : data_sync_elevel(LOG),
|
|
"could not close file \"%s\": %m", vfdP->fileName);
|
|
}
|
|
|
|
--nfile;
|
|
vfdP->fd = VFD_CLOSED;
|
|
|
|
/* remove the file from the lru ring */
|
|
Delete(file);
|
|
}
|
|
|
|
if (vfdP->fdstate & FD_TEMP_FILE_LIMIT)
|
|
{
|
|
/* Subtract its size from current usage (do first in case of error) */
|
|
temporary_files_size -= vfdP->fileSize;
|
|
vfdP->fileSize = 0;
|
|
}
|
|
|
|
/*
|
|
* Delete the file if it was temporary, and make a log entry if wanted
|
|
*/
|
|
if (vfdP->fdstate & FD_DELETE_AT_CLOSE)
|
|
{
|
|
struct stat filestats;
|
|
int stat_errno;
|
|
|
|
/*
|
|
* If we get an error, as could happen within the ereport/elog calls,
|
|
* we'll come right back here during transaction abort. Reset the
|
|
* flag to ensure that we can't get into an infinite loop. This code
|
|
* is arranged to ensure that the worst-case consequence is failing to
|
|
* emit log message(s), not failing to attempt the unlink.
|
|
*/
|
|
vfdP->fdstate &= ~FD_DELETE_AT_CLOSE;
|
|
|
|
|
|
/* first try the stat() */
|
|
if (stat(vfdP->fileName, &filestats))
|
|
stat_errno = errno;
|
|
else
|
|
stat_errno = 0;
|
|
|
|
/* in any case do the unlink */
|
|
if (unlink(vfdP->fileName))
|
|
ereport(LOG,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not delete file \"%s\": %m", vfdP->fileName)));
|
|
|
|
/* and last report the stat results */
|
|
if (stat_errno == 0)
|
|
ReportTemporaryFileUsage(vfdP->fileName, filestats.st_size);
|
|
else
|
|
{
|
|
errno = stat_errno;
|
|
ereport(LOG,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not stat file \"%s\": %m", vfdP->fileName)));
|
|
}
|
|
}
|
|
|
|
/* Unregister it from the resource owner */
|
|
if (vfdP->resowner)
|
|
ResourceOwnerForgetFile(vfdP->resowner, file);
|
|
|
|
/*
|
|
* Return the Vfd slot to the free list
|
|
*/
|
|
FreeVfd(file);
|
|
}
|
|
|
|
/*
|
|
* FilePrefetch - initiate asynchronous read of a given range of the file.
|
|
*
|
|
* Currently the only implementation of this function is using posix_fadvise
|
|
* which is the simplest standardized interface that accomplishes this.
|
|
* We could add an implementation using libaio in the future; but note that
|
|
* this API is inappropriate for libaio, which wants to have a buffer provided
|
|
* to read into.
|
|
*/
|
|
int
|
|
FilePrefetch(File file, off_t offset, int amount, uint32 wait_event_info)
|
|
{
|
|
#if defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_WILLNEED)
|
|
int returnCode;
|
|
|
|
Assert(FileIsValid(file));
|
|
|
|
DO_DB(elog(LOG, "FilePrefetch: %d (%s) " INT64_FORMAT " %d",
|
|
file, VfdCache[file].fileName,
|
|
(int64) offset, amount));
|
|
|
|
returnCode = FileAccess(file);
|
|
if (returnCode < 0)
|
|
return returnCode;
|
|
|
|
pgstat_report_wait_start(wait_event_info);
|
|
returnCode = posix_fadvise(VfdCache[file].fd, offset, amount,
|
|
POSIX_FADV_WILLNEED);
|
|
pgstat_report_wait_end();
|
|
|
|
return returnCode;
|
|
#else
|
|
Assert(FileIsValid(file));
|
|
return 0;
|
|
#endif
|
|
}
|
|
|
|
void
|
|
FileWriteback(File file, off_t offset, off_t nbytes, uint32 wait_event_info)
|
|
{
|
|
int returnCode;
|
|
|
|
Assert(FileIsValid(file));
|
|
|
|
DO_DB(elog(LOG, "FileWriteback: %d (%s) " INT64_FORMAT " " INT64_FORMAT,
|
|
file, VfdCache[file].fileName,
|
|
(int64) offset, (int64) nbytes));
|
|
|
|
if (nbytes <= 0)
|
|
return;
|
|
|
|
returnCode = FileAccess(file);
|
|
if (returnCode < 0)
|
|
return;
|
|
|
|
pgstat_report_wait_start(wait_event_info);
|
|
pg_flush_data(VfdCache[file].fd, offset, nbytes);
|
|
pgstat_report_wait_end();
|
|
}
|
|
|
|
int
|
|
FileRead(File file, char *buffer, int amount, off_t offset,
|
|
uint32 wait_event_info)
|
|
{
|
|
int returnCode;
|
|
Vfd *vfdP;
|
|
|
|
Assert(FileIsValid(file));
|
|
|
|
DO_DB(elog(LOG, "FileRead: %d (%s) " INT64_FORMAT " %d %p",
|
|
file, VfdCache[file].fileName,
|
|
(int64) offset,
|
|
amount, buffer));
|
|
|
|
returnCode = FileAccess(file);
|
|
if (returnCode < 0)
|
|
return returnCode;
|
|
|
|
vfdP = &VfdCache[file];
|
|
|
|
retry:
|
|
pgstat_report_wait_start(wait_event_info);
|
|
returnCode = pg_pread(vfdP->fd, buffer, amount, offset);
|
|
pgstat_report_wait_end();
|
|
|
|
if (returnCode < 0)
|
|
{
|
|
/*
|
|
* Windows may run out of kernel buffers and return "Insufficient
|
|
* system resources" error. Wait a bit and retry to solve it.
|
|
*
|
|
* It is rumored that EINTR is also possible on some Unix filesystems,
|
|
* in which case immediate retry is indicated.
|
|
*/
|
|
#ifdef WIN32
|
|
DWORD error = GetLastError();
|
|
|
|
switch (error)
|
|
{
|
|
case ERROR_NO_SYSTEM_RESOURCES:
|
|
pg_usleep(1000L);
|
|
errno = EINTR;
|
|
break;
|
|
default:
|
|
_dosmaperr(error);
|
|
break;
|
|
}
|
|
#endif
|
|
/* OK to retry if interrupted */
|
|
if (errno == EINTR)
|
|
goto retry;
|
|
}
|
|
|
|
return returnCode;
|
|
}
|
|
|
|
int
|
|
FileWrite(File file, char *buffer, int amount, off_t offset,
|
|
uint32 wait_event_info)
|
|
{
|
|
int returnCode;
|
|
Vfd *vfdP;
|
|
|
|
Assert(FileIsValid(file));
|
|
|
|
DO_DB(elog(LOG, "FileWrite: %d (%s) " INT64_FORMAT " %d %p",
|
|
file, VfdCache[file].fileName,
|
|
(int64) offset,
|
|
amount, buffer));
|
|
|
|
returnCode = FileAccess(file);
|
|
if (returnCode < 0)
|
|
return returnCode;
|
|
|
|
vfdP = &VfdCache[file];
|
|
|
|
/*
|
|
* If enforcing temp_file_limit and it's a temp file, check to see if the
|
|
* write would overrun temp_file_limit, and throw error if so. Note: it's
|
|
* really a modularity violation to throw error here; we should set errno
|
|
* and return -1. However, there's no way to report a suitable error
|
|
* message if we do that. All current callers would just throw error
|
|
* immediately anyway, so this is safe at present.
|
|
*/
|
|
if (temp_file_limit >= 0 && (vfdP->fdstate & FD_TEMP_FILE_LIMIT))
|
|
{
|
|
off_t past_write = offset + amount;
|
|
|
|
if (past_write > vfdP->fileSize)
|
|
{
|
|
uint64 newTotal = temporary_files_size;
|
|
|
|
newTotal += past_write - vfdP->fileSize;
|
|
if (newTotal > (uint64) temp_file_limit * (uint64) 1024)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED),
|
|
errmsg("temporary file size exceeds temp_file_limit (%dkB)",
|
|
temp_file_limit)));
|
|
}
|
|
}
|
|
|
|
retry:
|
|
errno = 0;
|
|
pgstat_report_wait_start(wait_event_info);
|
|
returnCode = pg_pwrite(VfdCache[file].fd, buffer, amount, offset);
|
|
pgstat_report_wait_end();
|
|
|
|
/* if write didn't set errno, assume problem is no disk space */
|
|
if (returnCode != amount && errno == 0)
|
|
errno = ENOSPC;
|
|
|
|
if (returnCode >= 0)
|
|
{
|
|
/*
|
|
* Maintain fileSize and temporary_files_size if it's a temp file.
|
|
*/
|
|
if (vfdP->fdstate & FD_TEMP_FILE_LIMIT)
|
|
{
|
|
off_t past_write = offset + amount;
|
|
|
|
if (past_write > vfdP->fileSize)
|
|
{
|
|
temporary_files_size += past_write - vfdP->fileSize;
|
|
vfdP->fileSize = past_write;
|
|
}
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/*
|
|
* See comments in FileRead()
|
|
*/
|
|
#ifdef WIN32
|
|
DWORD error = GetLastError();
|
|
|
|
switch (error)
|
|
{
|
|
case ERROR_NO_SYSTEM_RESOURCES:
|
|
pg_usleep(1000L);
|
|
errno = EINTR;
|
|
break;
|
|
default:
|
|
_dosmaperr(error);
|
|
break;
|
|
}
|
|
#endif
|
|
/* OK to retry if interrupted */
|
|
if (errno == EINTR)
|
|
goto retry;
|
|
}
|
|
|
|
return returnCode;
|
|
}
|
|
|
|
int
|
|
FileSync(File file, uint32 wait_event_info)
|
|
{
|
|
int returnCode;
|
|
|
|
Assert(FileIsValid(file));
|
|
|
|
DO_DB(elog(LOG, "FileSync: %d (%s)",
|
|
file, VfdCache[file].fileName));
|
|
|
|
returnCode = FileAccess(file);
|
|
if (returnCode < 0)
|
|
return returnCode;
|
|
|
|
pgstat_report_wait_start(wait_event_info);
|
|
returnCode = pg_fsync(VfdCache[file].fd);
|
|
pgstat_report_wait_end();
|
|
|
|
return returnCode;
|
|
}
|
|
|
|
off_t
|
|
FileSize(File file)
|
|
{
|
|
Assert(FileIsValid(file));
|
|
|
|
DO_DB(elog(LOG, "FileSize %d (%s)",
|
|
file, VfdCache[file].fileName));
|
|
|
|
if (FileIsNotOpen(file))
|
|
{
|
|
if (FileAccess(file) < 0)
|
|
return (off_t) -1;
|
|
}
|
|
|
|
return lseek(VfdCache[file].fd, 0, SEEK_END);
|
|
}
|
|
|
|
int
|
|
FileTruncate(File file, off_t offset, uint32 wait_event_info)
|
|
{
|
|
int returnCode;
|
|
|
|
Assert(FileIsValid(file));
|
|
|
|
DO_DB(elog(LOG, "FileTruncate %d (%s)",
|
|
file, VfdCache[file].fileName));
|
|
|
|
returnCode = FileAccess(file);
|
|
if (returnCode < 0)
|
|
return returnCode;
|
|
|
|
pgstat_report_wait_start(wait_event_info);
|
|
returnCode = ftruncate(VfdCache[file].fd, offset);
|
|
pgstat_report_wait_end();
|
|
|
|
if (returnCode == 0 && VfdCache[file].fileSize > offset)
|
|
{
|
|
/* adjust our state for truncation of a temp file */
|
|
Assert(VfdCache[file].fdstate & FD_TEMP_FILE_LIMIT);
|
|
temporary_files_size -= VfdCache[file].fileSize - offset;
|
|
VfdCache[file].fileSize = offset;
|
|
}
|
|
|
|
return returnCode;
|
|
}
|
|
|
|
/*
|
|
* Return the pathname associated with an open file.
|
|
*
|
|
* The returned string points to an internal buffer, which is valid until
|
|
* the file is closed.
|
|
*/
|
|
char *
|
|
FilePathName(File file)
|
|
{
|
|
Assert(FileIsValid(file));
|
|
|
|
return VfdCache[file].fileName;
|
|
}
|
|
|
|
/*
|
|
* Return the raw file descriptor of an opened file.
|
|
*
|
|
* The returned file descriptor will be valid until the file is closed, but
|
|
* there are a lot of things that can make that happen. So the caller should
|
|
* be careful not to do much of anything else before it finishes using the
|
|
* returned file descriptor.
|
|
*/
|
|
int
|
|
FileGetRawDesc(File file)
|
|
{
|
|
Assert(FileIsValid(file));
|
|
return VfdCache[file].fd;
|
|
}
|
|
|
|
/*
|
|
* FileGetRawFlags - returns the file flags on open(2)
|
|
*/
|
|
int
|
|
FileGetRawFlags(File file)
|
|
{
|
|
Assert(FileIsValid(file));
|
|
return VfdCache[file].fileFlags;
|
|
}
|
|
|
|
/*
|
|
* FileGetRawMode - returns the mode bitmask passed to open(2)
|
|
*/
|
|
mode_t
|
|
FileGetRawMode(File file)
|
|
{
|
|
Assert(FileIsValid(file));
|
|
return VfdCache[file].fileMode;
|
|
}
|
|
|
|
/*
|
|
* Make room for another allocatedDescs[] array entry if needed and possible.
|
|
* Returns true if an array element is available.
|
|
*/
|
|
static bool
|
|
reserveAllocatedDesc(void)
|
|
{
|
|
AllocateDesc *newDescs;
|
|
int newMax;
|
|
|
|
/* Quick out if array already has a free slot. */
|
|
if (numAllocatedDescs < maxAllocatedDescs)
|
|
return true;
|
|
|
|
/*
|
|
* If the array hasn't yet been created in the current process, initialize
|
|
* it with FD_MINFREE / 3 elements. In many scenarios this is as many as
|
|
* we will ever need, anyway. We don't want to look at max_safe_fds
|
|
* immediately because set_max_safe_fds() may not have run yet.
|
|
*/
|
|
if (allocatedDescs == NULL)
|
|
{
|
|
newMax = FD_MINFREE / 3;
|
|
newDescs = (AllocateDesc *) malloc(newMax * sizeof(AllocateDesc));
|
|
/* Out of memory already? Treat as fatal error. */
|
|
if (newDescs == NULL)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_OUT_OF_MEMORY),
|
|
errmsg("out of memory")));
|
|
allocatedDescs = newDescs;
|
|
maxAllocatedDescs = newMax;
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Consider enlarging the array beyond the initial allocation used above.
|
|
* By the time this happens, max_safe_fds should be known accurately.
|
|
*
|
|
* We mustn't let allocated descriptors hog all the available FDs, and in
|
|
* practice we'd better leave a reasonable number of FDs for VFD use. So
|
|
* set the maximum to max_safe_fds / 3. (This should certainly be at
|
|
* least as large as the initial size, FD_MINFREE / 3, so we aren't
|
|
* tightening the restriction here.) Recall that "external" FDs are
|
|
* allowed to consume another third of max_safe_fds.
|
|
*/
|
|
newMax = max_safe_fds / 3;
|
|
if (newMax > maxAllocatedDescs)
|
|
{
|
|
newDescs = (AllocateDesc *) realloc(allocatedDescs,
|
|
newMax * sizeof(AllocateDesc));
|
|
/* Treat out-of-memory as a non-fatal error. */
|
|
if (newDescs == NULL)
|
|
return false;
|
|
allocatedDescs = newDescs;
|
|
maxAllocatedDescs = newMax;
|
|
return true;
|
|
}
|
|
|
|
/* Can't enlarge allocatedDescs[] any more. */
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* Routines that want to use stdio (ie, FILE*) should use AllocateFile
|
|
* rather than plain fopen(). This lets fd.c deal with freeing FDs if
|
|
* necessary to open the file. When done, call FreeFile rather than fclose.
|
|
*
|
|
* Note that files that will be open for any significant length of time
|
|
* should NOT be handled this way, since they cannot share kernel file
|
|
* descriptors with other files; there is grave risk of running out of FDs
|
|
* if anyone locks down too many FDs. Most callers of this routine are
|
|
* simply reading a config file that they will read and close immediately.
|
|
*
|
|
* fd.c will automatically close all files opened with AllocateFile at
|
|
* transaction commit or abort; this prevents FD leakage if a routine
|
|
* that calls AllocateFile is terminated prematurely by ereport(ERROR).
|
|
*
|
|
* Ideally this should be the *only* direct call of fopen() in the backend.
|
|
*/
|
|
FILE *
|
|
AllocateFile(const char *name, const char *mode)
|
|
{
|
|
FILE *file;
|
|
|
|
DO_DB(elog(LOG, "AllocateFile: Allocated %d (%s)",
|
|
numAllocatedDescs, name));
|
|
|
|
/* Can we allocate another non-virtual FD? */
|
|
if (!reserveAllocatedDesc())
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_INSUFFICIENT_RESOURCES),
|
|
errmsg("exceeded maxAllocatedDescs (%d) while trying to open file \"%s\"",
|
|
maxAllocatedDescs, name)));
|
|
|
|
/* Close excess kernel FDs. */
|
|
ReleaseLruFiles();
|
|
|
|
TryAgain:
|
|
if ((file = fopen(name, mode)) != NULL)
|
|
{
|
|
AllocateDesc *desc = &allocatedDescs[numAllocatedDescs];
|
|
|
|
desc->kind = AllocateDescFile;
|
|
desc->desc.file = file;
|
|
desc->create_subid = GetCurrentSubTransactionId();
|
|
numAllocatedDescs++;
|
|
return desc->desc.file;
|
|
}
|
|
|
|
if (errno == EMFILE || errno == ENFILE)
|
|
{
|
|
int save_errno = errno;
|
|
|
|
ereport(LOG,
|
|
(errcode(ERRCODE_INSUFFICIENT_RESOURCES),
|
|
errmsg("out of file descriptors: %m; release and retry")));
|
|
errno = 0;
|
|
if (ReleaseLruFile())
|
|
goto TryAgain;
|
|
errno = save_errno;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Open a file with OpenTransientFilePerm() and pass default file mode for
|
|
* the fileMode parameter.
|
|
*/
|
|
int
|
|
OpenTransientFile(const char *fileName, int fileFlags)
|
|
{
|
|
return OpenTransientFilePerm(fileName, fileFlags, pg_file_create_mode);
|
|
}
|
|
|
|
/*
|
|
* Like AllocateFile, but returns an unbuffered fd like open(2)
|
|
*/
|
|
int
|
|
OpenTransientFilePerm(const char *fileName, int fileFlags, mode_t fileMode)
|
|
{
|
|
int fd;
|
|
|
|
DO_DB(elog(LOG, "OpenTransientFile: Allocated %d (%s)",
|
|
numAllocatedDescs, fileName));
|
|
|
|
/* Can we allocate another non-virtual FD? */
|
|
if (!reserveAllocatedDesc())
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_INSUFFICIENT_RESOURCES),
|
|
errmsg("exceeded maxAllocatedDescs (%d) while trying to open file \"%s\"",
|
|
maxAllocatedDescs, fileName)));
|
|
|
|
/* Close excess kernel FDs. */
|
|
ReleaseLruFiles();
|
|
|
|
fd = BasicOpenFilePerm(fileName, fileFlags, fileMode);
|
|
|
|
if (fd >= 0)
|
|
{
|
|
AllocateDesc *desc = &allocatedDescs[numAllocatedDescs];
|
|
|
|
desc->kind = AllocateDescRawFD;
|
|
desc->desc.fd = fd;
|
|
desc->create_subid = GetCurrentSubTransactionId();
|
|
numAllocatedDescs++;
|
|
|
|
return fd;
|
|
}
|
|
|
|
return -1; /* failure */
|
|
}
|
|
|
|
/*
|
|
* Routines that want to initiate a pipe stream should use OpenPipeStream
|
|
* rather than plain popen(). This lets fd.c deal with freeing FDs if
|
|
* necessary. When done, call ClosePipeStream rather than pclose.
|
|
*
|
|
* This function also ensures that the popen'd program is run with default
|
|
* SIGPIPE processing, rather than the SIG_IGN setting the backend normally
|
|
* uses. This ensures desirable response to, eg, closing a read pipe early.
|
|
*/
|
|
FILE *
|
|
OpenPipeStream(const char *command, const char *mode)
|
|
{
|
|
FILE *file;
|
|
int save_errno;
|
|
|
|
DO_DB(elog(LOG, "OpenPipeStream: Allocated %d (%s)",
|
|
numAllocatedDescs, command));
|
|
|
|
/* Can we allocate another non-virtual FD? */
|
|
if (!reserveAllocatedDesc())
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_INSUFFICIENT_RESOURCES),
|
|
errmsg("exceeded maxAllocatedDescs (%d) while trying to execute command \"%s\"",
|
|
maxAllocatedDescs, command)));
|
|
|
|
/* Close excess kernel FDs. */
|
|
ReleaseLruFiles();
|
|
|
|
TryAgain:
|
|
fflush(stdout);
|
|
fflush(stderr);
|
|
pqsignal(SIGPIPE, SIG_DFL);
|
|
errno = 0;
|
|
file = popen(command, mode);
|
|
save_errno = errno;
|
|
pqsignal(SIGPIPE, SIG_IGN);
|
|
errno = save_errno;
|
|
if (file != NULL)
|
|
{
|
|
AllocateDesc *desc = &allocatedDescs[numAllocatedDescs];
|
|
|
|
desc->kind = AllocateDescPipe;
|
|
desc->desc.file = file;
|
|
desc->create_subid = GetCurrentSubTransactionId();
|
|
numAllocatedDescs++;
|
|
return desc->desc.file;
|
|
}
|
|
|
|
if (errno == EMFILE || errno == ENFILE)
|
|
{
|
|
ereport(LOG,
|
|
(errcode(ERRCODE_INSUFFICIENT_RESOURCES),
|
|
errmsg("out of file descriptors: %m; release and retry")));
|
|
if (ReleaseLruFile())
|
|
goto TryAgain;
|
|
errno = save_errno;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Free an AllocateDesc of any type.
|
|
*
|
|
* The argument *must* point into the allocatedDescs[] array.
|
|
*/
|
|
static int
|
|
FreeDesc(AllocateDesc *desc)
|
|
{
|
|
int result;
|
|
|
|
/* Close the underlying object */
|
|
switch (desc->kind)
|
|
{
|
|
case AllocateDescFile:
|
|
result = fclose(desc->desc.file);
|
|
break;
|
|
case AllocateDescPipe:
|
|
result = pclose(desc->desc.file);
|
|
break;
|
|
case AllocateDescDir:
|
|
result = closedir(desc->desc.dir);
|
|
break;
|
|
case AllocateDescRawFD:
|
|
result = close(desc->desc.fd);
|
|
break;
|
|
default:
|
|
elog(ERROR, "AllocateDesc kind not recognized");
|
|
result = 0; /* keep compiler quiet */
|
|
break;
|
|
}
|
|
|
|
/* Compact storage in the allocatedDescs array */
|
|
numAllocatedDescs--;
|
|
*desc = allocatedDescs[numAllocatedDescs];
|
|
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* Close a file returned by AllocateFile.
|
|
*
|
|
* Note we do not check fclose's return value --- it is up to the caller
|
|
* to handle close errors.
|
|
*/
|
|
int
|
|
FreeFile(FILE *file)
|
|
{
|
|
int i;
|
|
|
|
DO_DB(elog(LOG, "FreeFile: Allocated %d", numAllocatedDescs));
|
|
|
|
/* Remove file from list of allocated files, if it's present */
|
|
for (i = numAllocatedDescs; --i >= 0;)
|
|
{
|
|
AllocateDesc *desc = &allocatedDescs[i];
|
|
|
|
if (desc->kind == AllocateDescFile && desc->desc.file == file)
|
|
return FreeDesc(desc);
|
|
}
|
|
|
|
/* Only get here if someone passes us a file not in allocatedDescs */
|
|
elog(WARNING, "file passed to FreeFile was not obtained from AllocateFile");
|
|
|
|
return fclose(file);
|
|
}
|
|
|
|
/*
|
|
* Close a file returned by OpenTransientFile.
|
|
*
|
|
* Note we do not check close's return value --- it is up to the caller
|
|
* to handle close errors.
|
|
*/
|
|
int
|
|
CloseTransientFile(int fd)
|
|
{
|
|
int i;
|
|
|
|
DO_DB(elog(LOG, "CloseTransientFile: Allocated %d", numAllocatedDescs));
|
|
|
|
/* Remove fd from list of allocated files, if it's present */
|
|
for (i = numAllocatedDescs; --i >= 0;)
|
|
{
|
|
AllocateDesc *desc = &allocatedDescs[i];
|
|
|
|
if (desc->kind == AllocateDescRawFD && desc->desc.fd == fd)
|
|
return FreeDesc(desc);
|
|
}
|
|
|
|
/* Only get here if someone passes us a file not in allocatedDescs */
|
|
elog(WARNING, "fd passed to CloseTransientFile was not obtained from OpenTransientFile");
|
|
|
|
return close(fd);
|
|
}
|
|
|
|
/*
|
|
* Routines that want to use <dirent.h> (ie, DIR*) should use AllocateDir
|
|
* rather than plain opendir(). This lets fd.c deal with freeing FDs if
|
|
* necessary to open the directory, and with closing it after an elog.
|
|
* When done, call FreeDir rather than closedir.
|
|
*
|
|
* Returns NULL, with errno set, on failure. Note that failure detection
|
|
* is commonly left to the following call of ReadDir or ReadDirExtended;
|
|
* see the comments for ReadDir.
|
|
*
|
|
* Ideally this should be the *only* direct call of opendir() in the backend.
|
|
*/
|
|
DIR *
|
|
AllocateDir(const char *dirname)
|
|
{
|
|
DIR *dir;
|
|
|
|
DO_DB(elog(LOG, "AllocateDir: Allocated %d (%s)",
|
|
numAllocatedDescs, dirname));
|
|
|
|
/* Can we allocate another non-virtual FD? */
|
|
if (!reserveAllocatedDesc())
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_INSUFFICIENT_RESOURCES),
|
|
errmsg("exceeded maxAllocatedDescs (%d) while trying to open directory \"%s\"",
|
|
maxAllocatedDescs, dirname)));
|
|
|
|
/* Close excess kernel FDs. */
|
|
ReleaseLruFiles();
|
|
|
|
TryAgain:
|
|
if ((dir = opendir(dirname)) != NULL)
|
|
{
|
|
AllocateDesc *desc = &allocatedDescs[numAllocatedDescs];
|
|
|
|
desc->kind = AllocateDescDir;
|
|
desc->desc.dir = dir;
|
|
desc->create_subid = GetCurrentSubTransactionId();
|
|
numAllocatedDescs++;
|
|
return desc->desc.dir;
|
|
}
|
|
|
|
if (errno == EMFILE || errno == ENFILE)
|
|
{
|
|
int save_errno = errno;
|
|
|
|
ereport(LOG,
|
|
(errcode(ERRCODE_INSUFFICIENT_RESOURCES),
|
|
errmsg("out of file descriptors: %m; release and retry")));
|
|
errno = 0;
|
|
if (ReleaseLruFile())
|
|
goto TryAgain;
|
|
errno = save_errno;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Read a directory opened with AllocateDir, ereport'ing any error.
|
|
*
|
|
* This is easier to use than raw readdir() since it takes care of some
|
|
* otherwise rather tedious and error-prone manipulation of errno. Also,
|
|
* if you are happy with a generic error message for AllocateDir failure,
|
|
* you can just do
|
|
*
|
|
* dir = AllocateDir(path);
|
|
* while ((dirent = ReadDir(dir, path)) != NULL)
|
|
* process dirent;
|
|
* FreeDir(dir);
|
|
*
|
|
* since a NULL dir parameter is taken as indicating AllocateDir failed.
|
|
* (Make sure errno isn't changed between AllocateDir and ReadDir if you
|
|
* use this shortcut.)
|
|
*
|
|
* The pathname passed to AllocateDir must be passed to this routine too,
|
|
* but it is only used for error reporting.
|
|
*/
|
|
struct dirent *
|
|
ReadDir(DIR *dir, const char *dirname)
|
|
{
|
|
return ReadDirExtended(dir, dirname, ERROR);
|
|
}
|
|
|
|
/*
|
|
* Alternate version of ReadDir that allows caller to specify the elevel
|
|
* for any error report (whether it's reporting an initial failure of
|
|
* AllocateDir or a subsequent directory read failure).
|
|
*
|
|
* If elevel < ERROR, returns NULL after any error. With the normal coding
|
|
* pattern, this will result in falling out of the loop immediately as
|
|
* though the directory contained no (more) entries.
|
|
*/
|
|
struct dirent *
|
|
ReadDirExtended(DIR *dir, const char *dirname, int elevel)
|
|
{
|
|
struct dirent *dent;
|
|
|
|
/* Give a generic message for AllocateDir failure, if caller didn't */
|
|
if (dir == NULL)
|
|
{
|
|
ereport(elevel,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not open directory \"%s\": %m",
|
|
dirname)));
|
|
return NULL;
|
|
}
|
|
|
|
errno = 0;
|
|
if ((dent = readdir(dir)) != NULL)
|
|
return dent;
|
|
|
|
if (errno)
|
|
ereport(elevel,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not read directory \"%s\": %m",
|
|
dirname)));
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Close a directory opened with AllocateDir.
|
|
*
|
|
* Returns closedir's return value (with errno set if it's not 0).
|
|
* Note we do not check the return value --- it is up to the caller
|
|
* to handle close errors if wanted.
|
|
*
|
|
* Does nothing if dir == NULL; we assume that directory open failure was
|
|
* already reported if desired.
|
|
*/
|
|
int
|
|
FreeDir(DIR *dir)
|
|
{
|
|
int i;
|
|
|
|
/* Nothing to do if AllocateDir failed */
|
|
if (dir == NULL)
|
|
return 0;
|
|
|
|
DO_DB(elog(LOG, "FreeDir: Allocated %d", numAllocatedDescs));
|
|
|
|
/* Remove dir from list of allocated dirs, if it's present */
|
|
for (i = numAllocatedDescs; --i >= 0;)
|
|
{
|
|
AllocateDesc *desc = &allocatedDescs[i];
|
|
|
|
if (desc->kind == AllocateDescDir && desc->desc.dir == dir)
|
|
return FreeDesc(desc);
|
|
}
|
|
|
|
/* Only get here if someone passes us a dir not in allocatedDescs */
|
|
elog(WARNING, "dir passed to FreeDir was not obtained from AllocateDir");
|
|
|
|
return closedir(dir);
|
|
}
|
|
|
|
|
|
/*
|
|
* Close a pipe stream returned by OpenPipeStream.
|
|
*/
|
|
int
|
|
ClosePipeStream(FILE *file)
|
|
{
|
|
int i;
|
|
|
|
DO_DB(elog(LOG, "ClosePipeStream: Allocated %d", numAllocatedDescs));
|
|
|
|
/* Remove file from list of allocated files, if it's present */
|
|
for (i = numAllocatedDescs; --i >= 0;)
|
|
{
|
|
AllocateDesc *desc = &allocatedDescs[i];
|
|
|
|
if (desc->kind == AllocateDescPipe && desc->desc.file == file)
|
|
return FreeDesc(desc);
|
|
}
|
|
|
|
/* Only get here if someone passes us a file not in allocatedDescs */
|
|
elog(WARNING, "file passed to ClosePipeStream was not obtained from OpenPipeStream");
|
|
|
|
return pclose(file);
|
|
}
|
|
|
|
/*
|
|
* closeAllVfds
|
|
*
|
|
* Force all VFDs into the physically-closed state, so that the fewest
|
|
* possible number of kernel file descriptors are in use. There is no
|
|
* change in the logical state of the VFDs.
|
|
*/
|
|
void
|
|
closeAllVfds(void)
|
|
{
|
|
Index i;
|
|
|
|
if (SizeVfdCache > 0)
|
|
{
|
|
Assert(FileIsNotOpen(0)); /* Make sure ring not corrupted */
|
|
for (i = 1; i < SizeVfdCache; i++)
|
|
{
|
|
if (!FileIsNotOpen(i))
|
|
LruDelete(i);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* SetTempTablespaces
|
|
*
|
|
* Define a list (actually an array) of OIDs of tablespaces to use for
|
|
* temporary files. This list will be used until end of transaction,
|
|
* unless this function is called again before then. It is caller's
|
|
* responsibility that the passed-in array has adequate lifespan (typically
|
|
* it'd be allocated in TopTransactionContext).
|
|
*
|
|
* Some entries of the array may be InvalidOid, indicating that the current
|
|
* database's default tablespace should be used.
|
|
*/
|
|
void
|
|
SetTempTablespaces(Oid *tableSpaces, int numSpaces)
|
|
{
|
|
Assert(numSpaces >= 0);
|
|
tempTableSpaces = tableSpaces;
|
|
numTempTableSpaces = numSpaces;
|
|
|
|
/*
|
|
* Select a random starting point in the list. This is to minimize
|
|
* conflicts between backends that are most likely sharing the same list
|
|
* of temp tablespaces. Note that if we create multiple temp files in the
|
|
* same transaction, we'll advance circularly through the list --- this
|
|
* ensures that large temporary sort files are nicely spread across all
|
|
* available tablespaces.
|
|
*/
|
|
if (numSpaces > 1)
|
|
nextTempTableSpace = random() % numSpaces;
|
|
else
|
|
nextTempTableSpace = 0;
|
|
}
|
|
|
|
/*
|
|
* TempTablespacesAreSet
|
|
*
|
|
* Returns true if SetTempTablespaces has been called in current transaction.
|
|
* (This is just so that tablespaces.c doesn't need its own per-transaction
|
|
* state.)
|
|
*/
|
|
bool
|
|
TempTablespacesAreSet(void)
|
|
{
|
|
return (numTempTableSpaces >= 0);
|
|
}
|
|
|
|
/*
|
|
* GetTempTablespaces
|
|
*
|
|
* Populate an array with the OIDs of the tablespaces that should be used for
|
|
* temporary files. (Some entries may be InvalidOid, indicating that the
|
|
* current database's default tablespace should be used.) At most numSpaces
|
|
* entries will be filled.
|
|
* Returns the number of OIDs that were copied into the output array.
|
|
*/
|
|
int
|
|
GetTempTablespaces(Oid *tableSpaces, int numSpaces)
|
|
{
|
|
int i;
|
|
|
|
Assert(TempTablespacesAreSet());
|
|
for (i = 0; i < numTempTableSpaces && i < numSpaces; ++i)
|
|
tableSpaces[i] = tempTableSpaces[i];
|
|
|
|
return i;
|
|
}
|
|
|
|
/*
|
|
* GetNextTempTableSpace
|
|
*
|
|
* Select the next temp tablespace to use. A result of InvalidOid means
|
|
* to use the current database's default tablespace.
|
|
*/
|
|
Oid
|
|
GetNextTempTableSpace(void)
|
|
{
|
|
if (numTempTableSpaces > 0)
|
|
{
|
|
/* Advance nextTempTableSpace counter with wraparound */
|
|
if (++nextTempTableSpace >= numTempTableSpaces)
|
|
nextTempTableSpace = 0;
|
|
return tempTableSpaces[nextTempTableSpace];
|
|
}
|
|
return InvalidOid;
|
|
}
|
|
|
|
|
|
/*
|
|
* AtEOSubXact_Files
|
|
*
|
|
* Take care of subtransaction commit/abort. At abort, we close temp files
|
|
* that the subtransaction may have opened. At commit, we reassign the
|
|
* files that were opened to the parent subtransaction.
|
|
*/
|
|
void
|
|
AtEOSubXact_Files(bool isCommit, SubTransactionId mySubid,
|
|
SubTransactionId parentSubid)
|
|
{
|
|
Index i;
|
|
|
|
for (i = 0; i < numAllocatedDescs; i++)
|
|
{
|
|
if (allocatedDescs[i].create_subid == mySubid)
|
|
{
|
|
if (isCommit)
|
|
allocatedDescs[i].create_subid = parentSubid;
|
|
else
|
|
{
|
|
/* have to recheck the item after FreeDesc (ugly) */
|
|
FreeDesc(&allocatedDescs[i--]);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* AtEOXact_Files
|
|
*
|
|
* This routine is called during transaction commit or abort. All still-open
|
|
* per-transaction temporary file VFDs are closed, which also causes the
|
|
* underlying files to be deleted (although they should've been closed already
|
|
* by the ResourceOwner cleanup). Furthermore, all "allocated" stdio files are
|
|
* closed. We also forget any transaction-local temp tablespace list.
|
|
*
|
|
* The isCommit flag is used only to decide whether to emit warnings about
|
|
* unclosed files.
|
|
*/
|
|
void
|
|
AtEOXact_Files(bool isCommit)
|
|
{
|
|
CleanupTempFiles(isCommit, false);
|
|
tempTableSpaces = NULL;
|
|
numTempTableSpaces = -1;
|
|
}
|
|
|
|
/*
|
|
* AtProcExit_Files
|
|
*
|
|
* on_proc_exit hook to clean up temp files during backend shutdown.
|
|
* Here, we want to clean up *all* temp files including interXact ones.
|
|
*/
|
|
static void
|
|
AtProcExit_Files(int code, Datum arg)
|
|
{
|
|
CleanupTempFiles(false, true);
|
|
}
|
|
|
|
/*
|
|
* Close temporary files and delete their underlying files.
|
|
*
|
|
* isCommit: if true, this is normal transaction commit, and we don't
|
|
* expect any remaining files; warn if there are some.
|
|
*
|
|
* isProcExit: if true, this is being called as the backend process is
|
|
* exiting. If that's the case, we should remove all temporary files; if
|
|
* that's not the case, we are being called for transaction commit/abort
|
|
* and should only remove transaction-local temp files. In either case,
|
|
* also clean up "allocated" stdio files, dirs and fds.
|
|
*/
|
|
static void
|
|
CleanupTempFiles(bool isCommit, bool isProcExit)
|
|
{
|
|
Index i;
|
|
|
|
/*
|
|
* Careful here: at proc_exit we need extra cleanup, not just
|
|
* xact_temporary files.
|
|
*/
|
|
if (isProcExit || have_xact_temporary_files)
|
|
{
|
|
Assert(FileIsNotOpen(0)); /* Make sure ring not corrupted */
|
|
for (i = 1; i < SizeVfdCache; i++)
|
|
{
|
|
unsigned short fdstate = VfdCache[i].fdstate;
|
|
|
|
if (((fdstate & FD_DELETE_AT_CLOSE) || (fdstate & FD_CLOSE_AT_EOXACT)) &&
|
|
VfdCache[i].fileName != NULL)
|
|
{
|
|
/*
|
|
* If we're in the process of exiting a backend process, close
|
|
* all temporary files. Otherwise, only close temporary files
|
|
* local to the current transaction. They should be closed by
|
|
* the ResourceOwner mechanism already, so this is just a
|
|
* debugging cross-check.
|
|
*/
|
|
if (isProcExit)
|
|
FileClose(i);
|
|
else if (fdstate & FD_CLOSE_AT_EOXACT)
|
|
{
|
|
elog(WARNING,
|
|
"temporary file %s not closed at end-of-transaction",
|
|
VfdCache[i].fileName);
|
|
FileClose(i);
|
|
}
|
|
}
|
|
}
|
|
|
|
have_xact_temporary_files = false;
|
|
}
|
|
|
|
/* Complain if any allocated files remain open at commit. */
|
|
if (isCommit && numAllocatedDescs > 0)
|
|
elog(WARNING, "%d temporary files and directories not closed at end-of-transaction",
|
|
numAllocatedDescs);
|
|
|
|
/* Clean up "allocated" stdio files, dirs and fds. */
|
|
while (numAllocatedDescs > 0)
|
|
FreeDesc(&allocatedDescs[0]);
|
|
}
|
|
|
|
|
|
/*
|
|
* Remove temporary and temporary relation files left over from a prior
|
|
* postmaster session
|
|
*
|
|
* This should be called during postmaster startup. It will forcibly
|
|
* remove any leftover files created by OpenTemporaryFile and any leftover
|
|
* temporary relation files created by mdcreate.
|
|
*
|
|
* NOTE: we could, but don't, call this during a post-backend-crash restart
|
|
* cycle. The argument for not doing it is that someone might want to examine
|
|
* the temp files for debugging purposes. This does however mean that
|
|
* OpenTemporaryFile had better allow for collision with an existing temp
|
|
* file name.
|
|
*
|
|
* NOTE: this function and its subroutines generally report syscall failures
|
|
* with ereport(LOG) and keep going. Removing temp files is not so critical
|
|
* that we should fail to start the database when we can't do it.
|
|
*/
|
|
void
|
|
RemovePgTempFiles(void)
|
|
{
|
|
char temp_path[MAXPGPATH + 10 + sizeof(TABLESPACE_VERSION_DIRECTORY) + sizeof(PG_TEMP_FILES_DIR)];
|
|
DIR *spc_dir;
|
|
struct dirent *spc_de;
|
|
|
|
/*
|
|
* First process temp files in pg_default ($PGDATA/base)
|
|
*/
|
|
snprintf(temp_path, sizeof(temp_path), "base/%s", PG_TEMP_FILES_DIR);
|
|
RemovePgTempFilesInDir(temp_path, true, false);
|
|
RemovePgTempRelationFiles("base");
|
|
|
|
/*
|
|
* Cycle through temp directories for all non-default tablespaces.
|
|
*/
|
|
spc_dir = AllocateDir("pg_tblspc");
|
|
|
|
while ((spc_de = ReadDirExtended(spc_dir, "pg_tblspc", LOG)) != NULL)
|
|
{
|
|
if (strcmp(spc_de->d_name, ".") == 0 ||
|
|
strcmp(spc_de->d_name, "..") == 0)
|
|
continue;
|
|
|
|
snprintf(temp_path, sizeof(temp_path), "pg_tblspc/%s/%s/%s",
|
|
spc_de->d_name, TABLESPACE_VERSION_DIRECTORY, PG_TEMP_FILES_DIR);
|
|
RemovePgTempFilesInDir(temp_path, true, false);
|
|
|
|
snprintf(temp_path, sizeof(temp_path), "pg_tblspc/%s/%s",
|
|
spc_de->d_name, TABLESPACE_VERSION_DIRECTORY);
|
|
RemovePgTempRelationFiles(temp_path);
|
|
}
|
|
|
|
FreeDir(spc_dir);
|
|
|
|
/*
|
|
* In EXEC_BACKEND case there is a pgsql_tmp directory at the top level of
|
|
* DataDir as well. However, that is *not* cleaned here because doing so
|
|
* would create a race condition. It's done separately, earlier in
|
|
* postmaster startup.
|
|
*/
|
|
}
|
|
|
|
/*
|
|
* Process one pgsql_tmp directory for RemovePgTempFiles.
|
|
*
|
|
* If missing_ok is true, it's all right for the named directory to not exist.
|
|
* Any other problem results in a LOG message. (missing_ok should be true at
|
|
* the top level, since pgsql_tmp directories are not created until needed.)
|
|
*
|
|
* At the top level, this should be called with unlink_all = false, so that
|
|
* only files matching the temporary name prefix will be unlinked. When
|
|
* recursing it will be called with unlink_all = true to unlink everything
|
|
* under a top-level temporary directory.
|
|
*
|
|
* (These two flags could be replaced by one, but it seems clearer to keep
|
|
* them separate.)
|
|
*/
|
|
void
|
|
RemovePgTempFilesInDir(const char *tmpdirname, bool missing_ok, bool unlink_all)
|
|
{
|
|
DIR *temp_dir;
|
|
struct dirent *temp_de;
|
|
char rm_path[MAXPGPATH * 2];
|
|
|
|
temp_dir = AllocateDir(tmpdirname);
|
|
|
|
if (temp_dir == NULL && errno == ENOENT && missing_ok)
|
|
return;
|
|
|
|
while ((temp_de = ReadDirExtended(temp_dir, tmpdirname, LOG)) != NULL)
|
|
{
|
|
if (strcmp(temp_de->d_name, ".") == 0 ||
|
|
strcmp(temp_de->d_name, "..") == 0)
|
|
continue;
|
|
|
|
snprintf(rm_path, sizeof(rm_path), "%s/%s",
|
|
tmpdirname, temp_de->d_name);
|
|
|
|
if (unlink_all ||
|
|
strncmp(temp_de->d_name,
|
|
PG_TEMP_FILE_PREFIX,
|
|
strlen(PG_TEMP_FILE_PREFIX)) == 0)
|
|
{
|
|
struct stat statbuf;
|
|
|
|
if (lstat(rm_path, &statbuf) < 0)
|
|
{
|
|
ereport(LOG,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not stat file \"%s\": %m", rm_path)));
|
|
continue;
|
|
}
|
|
|
|
if (S_ISDIR(statbuf.st_mode))
|
|
{
|
|
/* recursively remove contents, then directory itself */
|
|
RemovePgTempFilesInDir(rm_path, false, true);
|
|
|
|
if (rmdir(rm_path) < 0)
|
|
ereport(LOG,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not remove directory \"%s\": %m",
|
|
rm_path)));
|
|
}
|
|
else
|
|
{
|
|
if (unlink(rm_path) < 0)
|
|
ereport(LOG,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not remove file \"%s\": %m",
|
|
rm_path)));
|
|
}
|
|
}
|
|
else
|
|
ereport(LOG,
|
|
(errmsg("unexpected file found in temporary-files directory: \"%s\"",
|
|
rm_path)));
|
|
}
|
|
|
|
FreeDir(temp_dir);
|
|
}
|
|
|
|
/* Process one tablespace directory, look for per-DB subdirectories */
|
|
static void
|
|
RemovePgTempRelationFiles(const char *tsdirname)
|
|
{
|
|
DIR *ts_dir;
|
|
struct dirent *de;
|
|
char dbspace_path[MAXPGPATH * 2];
|
|
|
|
ts_dir = AllocateDir(tsdirname);
|
|
|
|
while ((de = ReadDirExtended(ts_dir, tsdirname, LOG)) != NULL)
|
|
{
|
|
/*
|
|
* We're only interested in the per-database directories, which have
|
|
* numeric names. Note that this code will also (properly) ignore "."
|
|
* and "..".
|
|
*/
|
|
if (strspn(de->d_name, "0123456789") != strlen(de->d_name))
|
|
continue;
|
|
|
|
snprintf(dbspace_path, sizeof(dbspace_path), "%s/%s",
|
|
tsdirname, de->d_name);
|
|
RemovePgTempRelationFilesInDbspace(dbspace_path);
|
|
}
|
|
|
|
FreeDir(ts_dir);
|
|
}
|
|
|
|
/* Process one per-dbspace directory for RemovePgTempRelationFiles */
|
|
static void
|
|
RemovePgTempRelationFilesInDbspace(const char *dbspacedirname)
|
|
{
|
|
DIR *dbspace_dir;
|
|
struct dirent *de;
|
|
char rm_path[MAXPGPATH * 2];
|
|
|
|
dbspace_dir = AllocateDir(dbspacedirname);
|
|
|
|
while ((de = ReadDirExtended(dbspace_dir, dbspacedirname, LOG)) != NULL)
|
|
{
|
|
if (!looks_like_temp_rel_name(de->d_name))
|
|
continue;
|
|
|
|
snprintf(rm_path, sizeof(rm_path), "%s/%s",
|
|
dbspacedirname, de->d_name);
|
|
|
|
if (unlink(rm_path) < 0)
|
|
ereport(LOG,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not remove file \"%s\": %m",
|
|
rm_path)));
|
|
}
|
|
|
|
FreeDir(dbspace_dir);
|
|
}
|
|
|
|
/* t<digits>_<digits>, or t<digits>_<digits>_<forkname> */
|
|
bool
|
|
looks_like_temp_rel_name(const char *name)
|
|
{
|
|
int pos;
|
|
int savepos;
|
|
|
|
/* Must start with "t". */
|
|
if (name[0] != 't')
|
|
return false;
|
|
|
|
/* Followed by a non-empty string of digits and then an underscore. */
|
|
for (pos = 1; isdigit((unsigned char) name[pos]); ++pos)
|
|
;
|
|
if (pos == 1 || name[pos] != '_')
|
|
return false;
|
|
|
|
/* Followed by another nonempty string of digits. */
|
|
for (savepos = ++pos; isdigit((unsigned char) name[pos]); ++pos)
|
|
;
|
|
if (savepos == pos)
|
|
return false;
|
|
|
|
/* We might have _forkname or .segment or both. */
|
|
if (name[pos] == '_')
|
|
{
|
|
int forkchar = forkname_chars(&name[pos + 1], NULL);
|
|
|
|
if (forkchar <= 0)
|
|
return false;
|
|
pos += forkchar + 1;
|
|
}
|
|
if (name[pos] == '.')
|
|
{
|
|
int segchar;
|
|
|
|
for (segchar = 1; isdigit((unsigned char) name[pos + segchar]); ++segchar)
|
|
;
|
|
if (segchar <= 1)
|
|
return false;
|
|
pos += segchar;
|
|
}
|
|
|
|
/* Now we should be at the end. */
|
|
if (name[pos] != '\0')
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
|
|
/*
|
|
* Issue fsync recursively on PGDATA and all its contents.
|
|
*
|
|
* We fsync regular files and directories wherever they are, but we
|
|
* follow symlinks only for pg_wal and immediately under pg_tblspc.
|
|
* Other symlinks are presumed to point at files we're not responsible
|
|
* for fsyncing, and might not have privileges to write at all.
|
|
*
|
|
* Errors are logged but not considered fatal; that's because this is used
|
|
* only during database startup, to deal with the possibility that there are
|
|
* issued-but-unsynced writes pending against the data directory. We want to
|
|
* ensure that such writes reach disk before anything that's done in the new
|
|
* run. However, aborting on error would result in failure to start for
|
|
* harmless cases such as read-only files in the data directory, and that's
|
|
* not good either.
|
|
*
|
|
* Note that if we previously crashed due to a PANIC on fsync(), we'll be
|
|
* rewriting all changes again during recovery.
|
|
*
|
|
* Note we assume we're chdir'd into PGDATA to begin with.
|
|
*/
|
|
void
|
|
SyncDataDirectory(void)
|
|
{
|
|
bool xlog_is_symlink;
|
|
|
|
/* We can skip this whole thing if fsync is disabled. */
|
|
if (!enableFsync)
|
|
return;
|
|
|
|
/*
|
|
* If pg_wal is a symlink, we'll need to recurse into it separately,
|
|
* because the first walkdir below will ignore it.
|
|
*/
|
|
xlog_is_symlink = false;
|
|
|
|
#ifndef WIN32
|
|
{
|
|
struct stat st;
|
|
|
|
if (lstat("pg_wal", &st) < 0)
|
|
ereport(LOG,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not stat file \"%s\": %m",
|
|
"pg_wal")));
|
|
else if (S_ISLNK(st.st_mode))
|
|
xlog_is_symlink = true;
|
|
}
|
|
#else
|
|
if (pgwin32_is_junction("pg_wal"))
|
|
xlog_is_symlink = true;
|
|
#endif
|
|
|
|
/*
|
|
* If possible, hint to the kernel that we're soon going to fsync the data
|
|
* directory and its contents. Errors in this step are even less
|
|
* interesting than normal, so log them only at DEBUG1.
|
|
*/
|
|
#ifdef PG_FLUSH_DATA_WORKS
|
|
walkdir(".", pre_sync_fname, false, DEBUG1);
|
|
if (xlog_is_symlink)
|
|
walkdir("pg_wal", pre_sync_fname, false, DEBUG1);
|
|
walkdir("pg_tblspc", pre_sync_fname, true, DEBUG1);
|
|
#endif
|
|
|
|
/*
|
|
* Now we do the fsync()s in the same order.
|
|
*
|
|
* The main call ignores symlinks, so in addition to specially processing
|
|
* pg_wal if it's a symlink, pg_tblspc has to be visited separately with
|
|
* process_symlinks = true. Note that if there are any plain directories
|
|
* in pg_tblspc, they'll get fsync'd twice. That's not an expected case
|
|
* so we don't worry about optimizing it.
|
|
*/
|
|
walkdir(".", datadir_fsync_fname, false, LOG);
|
|
if (xlog_is_symlink)
|
|
walkdir("pg_wal", datadir_fsync_fname, false, LOG);
|
|
walkdir("pg_tblspc", datadir_fsync_fname, true, LOG);
|
|
}
|
|
|
|
/*
|
|
* walkdir: recursively walk a directory, applying the action to each
|
|
* regular file and directory (including the named directory itself).
|
|
*
|
|
* If process_symlinks is true, the action and recursion are also applied
|
|
* to regular files and directories that are pointed to by symlinks in the
|
|
* given directory; otherwise symlinks are ignored. Symlinks are always
|
|
* ignored in subdirectories, ie we intentionally don't pass down the
|
|
* process_symlinks flag to recursive calls.
|
|
*
|
|
* Errors are reported at level elevel, which might be ERROR or less.
|
|
*
|
|
* See also walkdir in file_utils.c, which is a frontend version of this
|
|
* logic.
|
|
*/
|
|
static void
|
|
walkdir(const char *path,
|
|
void (*action) (const char *fname, bool isdir, int elevel),
|
|
bool process_symlinks,
|
|
int elevel)
|
|
{
|
|
DIR *dir;
|
|
struct dirent *de;
|
|
|
|
dir = AllocateDir(path);
|
|
|
|
while ((de = ReadDirExtended(dir, path, elevel)) != NULL)
|
|
{
|
|
char subpath[MAXPGPATH * 2];
|
|
|
|
CHECK_FOR_INTERRUPTS();
|
|
|
|
if (strcmp(de->d_name, ".") == 0 ||
|
|
strcmp(de->d_name, "..") == 0)
|
|
continue;
|
|
|
|
snprintf(subpath, sizeof(subpath), "%s/%s", path, de->d_name);
|
|
|
|
switch (get_dirent_type(subpath, de, process_symlinks, elevel))
|
|
{
|
|
case PGFILETYPE_REG:
|
|
(*action) (subpath, false, elevel);
|
|
break;
|
|
case PGFILETYPE_DIR:
|
|
walkdir(subpath, action, false, elevel);
|
|
break;
|
|
default:
|
|
|
|
/*
|
|
* Errors are already reported directly by get_dirent_type(),
|
|
* and any remaining symlinks and unknown file types are
|
|
* ignored.
|
|
*/
|
|
break;
|
|
}
|
|
}
|
|
|
|
FreeDir(dir); /* we ignore any error here */
|
|
|
|
/*
|
|
* It's important to fsync the destination directory itself as individual
|
|
* file fsyncs don't guarantee that the directory entry for the file is
|
|
* synced. However, skip this if AllocateDir failed; the action function
|
|
* might not be robust against that.
|
|
*/
|
|
if (dir)
|
|
(*action) (path, true, elevel);
|
|
}
|
|
|
|
|
|
/*
|
|
* Hint to the OS that it should get ready to fsync() this file.
|
|
*
|
|
* Ignores errors trying to open unreadable files, and logs other errors at a
|
|
* caller-specified level.
|
|
*/
|
|
#ifdef PG_FLUSH_DATA_WORKS
|
|
|
|
static void
|
|
pre_sync_fname(const char *fname, bool isdir, int elevel)
|
|
{
|
|
int fd;
|
|
|
|
/* Don't try to flush directories, it'll likely just fail */
|
|
if (isdir)
|
|
return;
|
|
|
|
fd = OpenTransientFile(fname, O_RDONLY | PG_BINARY);
|
|
|
|
if (fd < 0)
|
|
{
|
|
if (errno == EACCES)
|
|
return;
|
|
ereport(elevel,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not open file \"%s\": %m", fname)));
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* pg_flush_data() ignores errors, which is ok because this is only a
|
|
* hint.
|
|
*/
|
|
pg_flush_data(fd, 0, 0);
|
|
|
|
if (CloseTransientFile(fd) != 0)
|
|
ereport(elevel,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not close file \"%s\": %m", fname)));
|
|
}
|
|
|
|
#endif /* PG_FLUSH_DATA_WORKS */
|
|
|
|
static void
|
|
datadir_fsync_fname(const char *fname, bool isdir, int elevel)
|
|
{
|
|
/*
|
|
* We want to silently ignoring errors about unreadable files. Pass that
|
|
* desire on to fsync_fname_ext().
|
|
*/
|
|
fsync_fname_ext(fname, isdir, true, elevel);
|
|
}
|
|
|
|
static void
|
|
unlink_if_exists_fname(const char *fname, bool isdir, int elevel)
|
|
{
|
|
if (isdir)
|
|
{
|
|
if (rmdir(fname) != 0 && errno != ENOENT)
|
|
ereport(elevel,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not remove directory \"%s\": %m", fname)));
|
|
}
|
|
else
|
|
{
|
|
/* Use PathNameDeleteTemporaryFile to report filesize */
|
|
PathNameDeleteTemporaryFile(fname, false);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* fsync_fname_ext -- Try to fsync a file or directory
|
|
*
|
|
* If ignore_perm is true, ignore errors upon trying to open unreadable
|
|
* files. Logs other errors at a caller-specified level.
|
|
*
|
|
* Returns 0 if the operation succeeded, -1 otherwise.
|
|
*/
|
|
int
|
|
fsync_fname_ext(const char *fname, bool isdir, bool ignore_perm, int elevel)
|
|
{
|
|
int fd;
|
|
int flags;
|
|
int returncode;
|
|
|
|
/*
|
|
* Some OSs require directories to be opened read-only whereas other
|
|
* systems don't allow us to fsync files opened read-only; so we need both
|
|
* cases here. Using O_RDWR will cause us to fail to fsync files that are
|
|
* not writable by our userid, but we assume that's OK.
|
|
*/
|
|
flags = PG_BINARY;
|
|
if (!isdir)
|
|
flags |= O_RDWR;
|
|
else
|
|
flags |= O_RDONLY;
|
|
|
|
fd = OpenTransientFile(fname, flags);
|
|
|
|
/*
|
|
* Some OSs don't allow us to open directories at all (Windows returns
|
|
* EACCES), just ignore the error in that case. If desired also silently
|
|
* ignoring errors about unreadable files. Log others.
|
|
*/
|
|
if (fd < 0 && isdir && (errno == EISDIR || errno == EACCES))
|
|
return 0;
|
|
else if (fd < 0 && ignore_perm && errno == EACCES)
|
|
return 0;
|
|
else if (fd < 0)
|
|
{
|
|
ereport(elevel,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not open file \"%s\": %m", fname)));
|
|
return -1;
|
|
}
|
|
|
|
returncode = pg_fsync(fd);
|
|
|
|
/*
|
|
* Some OSes don't allow us to fsync directories at all, so we can ignore
|
|
* those errors. Anything else needs to be logged.
|
|
*/
|
|
if (returncode != 0 && !(isdir && (errno == EBADF || errno == EINVAL)))
|
|
{
|
|
int save_errno;
|
|
|
|
/* close file upon error, might not be in transaction context */
|
|
save_errno = errno;
|
|
(void) CloseTransientFile(fd);
|
|
errno = save_errno;
|
|
|
|
ereport(elevel,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not fsync file \"%s\": %m", fname)));
|
|
return -1;
|
|
}
|
|
|
|
if (CloseTransientFile(fd) != 0)
|
|
{
|
|
ereport(elevel,
|
|
(errcode_for_file_access(),
|
|
errmsg("could not close file \"%s\": %m", fname)));
|
|
return -1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* fsync_parent_path -- fsync the parent path of a file or directory
|
|
*
|
|
* This is aimed at making file operations persistent on disk in case of
|
|
* an OS crash or power failure.
|
|
*/
|
|
static int
|
|
fsync_parent_path(const char *fname, int elevel)
|
|
{
|
|
char parentpath[MAXPGPATH];
|
|
|
|
strlcpy(parentpath, fname, MAXPGPATH);
|
|
get_parent_directory(parentpath);
|
|
|
|
/*
|
|
* get_parent_directory() returns an empty string if the input argument is
|
|
* just a file name (see comments in path.c), so handle that as being the
|
|
* current directory.
|
|
*/
|
|
if (strlen(parentpath) == 0)
|
|
strlcpy(parentpath, ".", MAXPGPATH);
|
|
|
|
if (fsync_fname_ext(parentpath, true, false, elevel) != 0)
|
|
return -1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Create a PostgreSQL data sub-directory
|
|
*
|
|
* The data directory itself, and most of its sub-directories, are created at
|
|
* initdb time, but we do have some occasions when we create directories in
|
|
* the backend (CREATE TABLESPACE, for example). In those cases, we want to
|
|
* make sure that those directories are created consistently. Today, that means
|
|
* making sure that the created directory has the correct permissions, which is
|
|
* what pg_dir_create_mode tracks for us.
|
|
*
|
|
* Note that we also set the umask() based on what we understand the correct
|
|
* permissions to be (see file_perm.c).
|
|
*
|
|
* For permissions other than the default, mkdir() can be used directly, but
|
|
* be sure to consider carefully such cases -- a sub-directory with incorrect
|
|
* permissions in a PostgreSQL data directory could cause backups and other
|
|
* processes to fail.
|
|
*/
|
|
int
|
|
MakePGDirectory(const char *directoryName)
|
|
{
|
|
return mkdir(directoryName, pg_dir_create_mode);
|
|
}
|
|
|
|
/*
|
|
* Return the passed-in error level, or PANIC if data_sync_retry is off.
|
|
*
|
|
* Failure to fsync any data file is cause for immediate panic, unless
|
|
* data_sync_retry is enabled. Data may have been written to the operating
|
|
* system and removed from our buffer pool already, and if we are running on
|
|
* an operating system that forgets dirty data on write-back failure, there
|
|
* may be only one copy of the data remaining: in the WAL. A later attempt to
|
|
* fsync again might falsely report success. Therefore we must not allow any
|
|
* further checkpoints to be attempted. data_sync_retry can in theory be
|
|
* enabled on systems known not to drop dirty buffered data on write-back
|
|
* failure (with the likely outcome that checkpoints will continue to fail
|
|
* until the underlying problem is fixed).
|
|
*
|
|
* Any code that reports a failure from fsync() or related functions should
|
|
* filter the error level with this function.
|
|
*/
|
|
int
|
|
data_sync_elevel(int elevel)
|
|
{
|
|
return data_sync_retry ? elevel : PANIC;
|
|
}
|