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src/include/storage/fd.h
248 строк
9 KB
Thomas Munro
Add file_extend_method=posix_fallocate,write_zeros.
06 фев 2026, 07:38
06 фев 2026, 07:38
f94e914
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/*------------------------------------------------------------------------- * * fd.h * Virtual file descriptor definitions. * * * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * src/include/storage/fd.h * *------------------------------------------------------------------------- */ /* * calls: * * File {Close, Read, ReadV, Write, WriteV, Size, Sync} * {Path Name Open, Allocate, Free} File * * These are NOT JUST RENAMINGS OF THE UNIX ROUTINES. * Use them for all file activity... * * File fd; * fd = PathNameOpenFile("foo", O_RDONLY); * * AllocateFile(); * FreeFile(); * * Use AllocateFile, not fopen, if you need a stdio file (FILE*); then * use FreeFile, not fclose, to close it. AVOID using stdio for files * that you intend to hold open for any length of time, since there is * no way for them to share kernel file descriptors with other files. * * Likewise, use AllocateDir/FreeDir, not opendir/closedir, to allocate * open directories (DIR*), and OpenTransientFile/CloseTransientFile for an * unbuffered file descriptor. * * If you really can't use any of the above, at least call AcquireExternalFD * or ReserveExternalFD to report any file descriptors that are held for any * length of time. Failure to do so risks unnecessary EMFILE errors. */ #ifndef FD_H #define FD_H #include "port/pg_iovec.h" #include <dirent.h> #include <fcntl.h> typedef int File; #define IO_DIRECT_DATA 0x01 #define IO_DIRECT_WAL 0x02 #define IO_DIRECT_WAL_INIT 0x04 enum FileExtendMethod { #ifdef HAVE_POSIX_FALLOCATE FILE_EXTEND_METHOD_POSIX_FALLOCATE, #endif FILE_EXTEND_METHOD_WRITE_ZEROS, }; /* Default to the first available file_extend_method. */ #define DEFAULT_FILE_EXTEND_METHOD 0 /* GUC parameter */ extern PGDLLIMPORT int max_files_per_process; extern PGDLLIMPORT bool data_sync_retry; extern PGDLLIMPORT int recovery_init_sync_method; extern PGDLLIMPORT int io_direct_flags; extern PGDLLIMPORT int file_extend_method; /* * This is private to fd.c, but exported for save/restore_backend_variables() */ extern PGDLLIMPORT int max_safe_fds; /* * On Windows, we have to interpret EACCES as possibly meaning the same as * ENOENT, because if a file is unlinked-but-not-yet-gone on that platform, * that's what you get. Ugh. This code is designed so that we don't * actually believe these cases are okay without further evidence (namely, * a pending fsync request getting canceled ... see ProcessSyncRequests). */ #ifndef WIN32 #define FILE_POSSIBLY_DELETED(err) ((err) == ENOENT) #else #define FILE_POSSIBLY_DELETED(err) ((err) == ENOENT || (err) == EACCES) #endif /* * O_DIRECT is not standard, but almost every Unix has it. We translate it * to the appropriate Windows flag in src/port/open.c. We simulate it with * fcntl(F_NOCACHE) on macOS inside fd.c's open() wrapper. We use the name * PG_O_DIRECT rather than defining O_DIRECT in that case (probably not a good * idea on a Unix). */ #if defined(O_DIRECT) #define PG_O_DIRECT O_DIRECT #elif defined(F_NOCACHE) #define PG_O_DIRECT 0x80000000 #define PG_O_DIRECT_USE_F_NOCACHE /* * The value we defined to stand in for O_DIRECT when simulating it with * F_NOCACHE had better not collide with any of the standard flags. */ StaticAssertDecl((PG_O_DIRECT & (O_APPEND | O_CLOEXEC | O_CREAT | O_DSYNC | O_EXCL | O_RDWR | O_RDONLY | O_SYNC | O_TRUNC | O_WRONLY)) == 0, "PG_O_DIRECT value collides with standard flag"); #else #define PG_O_DIRECT 0 #endif /* * prototypes for functions in fd.c */ struct PgAioHandle; /* Operations on virtual Files --- equivalent to Unix kernel file ops */ extern File PathNameOpenFile(const char *fileName, int fileFlags); extern File PathNameOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode); extern File OpenTemporaryFile(bool interXact); extern void FileClose(File file); extern int FilePrefetch(File file, pgoff_t offset, pgoff_t amount, uint32 wait_event_info); extern ssize_t FileReadV(File file, const struct iovec *iov, int iovcnt, pgoff_t offset, uint32 wait_event_info); extern ssize_t FileWriteV(File file, const struct iovec *iov, int iovcnt, pgoff_t offset, uint32 wait_event_info); extern int FileStartReadV(struct PgAioHandle *ioh, File file, int iovcnt, pgoff_t offset, uint32 wait_event_info); extern int FileSync(File file, uint32 wait_event_info); extern int FileZero(File file, pgoff_t offset, pgoff_t amount, uint32 wait_event_info); extern int FileFallocate(File file, pgoff_t offset, pgoff_t amount, uint32 wait_event_info); extern pgoff_t FileSize(File file); extern int FileTruncate(File file, pgoff_t offset, uint32 wait_event_info); extern void FileWriteback(File file, pgoff_t offset, pgoff_t nbytes, uint32 wait_event_info); extern char *FilePathName(File file); extern int FileGetRawDesc(File file); extern int FileGetRawFlags(File file); extern mode_t FileGetRawMode(File file); /* Operations used for sharing named temporary files */ extern File PathNameCreateTemporaryFile(const char *path, bool error_on_failure); extern File PathNameOpenTemporaryFile(const char *path, int mode); extern bool PathNameDeleteTemporaryFile(const char *path, bool error_on_failure); extern void PathNameCreateTemporaryDir(const char *basedir, const char *directory); extern void PathNameDeleteTemporaryDir(const char *dirname); extern void TempTablespacePath(char *path, Oid tablespace); /* Operations that allow use of regular stdio --- USE WITH CAUTION */ extern FILE *AllocateFile(const char *name, const char *mode); extern int FreeFile(FILE *file); /* Operations that allow use of pipe streams (popen/pclose) */ extern FILE *OpenPipeStream(const char *command, const char *mode); extern int ClosePipeStream(FILE *file); /* Operations to allow use of the <dirent.h> library routines */ extern DIR *AllocateDir(const char *dirname); extern struct dirent *ReadDir(DIR *dir, const char *dirname); extern struct dirent *ReadDirExtended(DIR *dir, const char *dirname, int elevel); extern int FreeDir(DIR *dir); /* Operations to allow use of a plain kernel FD, with automatic cleanup */ extern int OpenTransientFile(const char *fileName, int fileFlags); extern int OpenTransientFilePerm(const char *fileName, int fileFlags, mode_t fileMode); extern int CloseTransientFile(int fd); /* If you've really really gotta have a plain kernel FD, use this */ extern int BasicOpenFile(const char *fileName, int fileFlags); extern int BasicOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode); /* Use these for other cases, and also for long-lived BasicOpenFile FDs */ extern bool AcquireExternalFD(void); extern void ReserveExternalFD(void); extern void ReleaseExternalFD(void); /* Make a directory with default permissions */ extern int MakePGDirectory(const char *directoryName); /* Miscellaneous support routines */ extern void InitFileAccess(void); extern void InitTemporaryFileAccess(void); extern void set_max_safe_fds(void); extern void closeAllVfds(void); extern void SetTempTablespaces(Oid *tableSpaces, int numSpaces); extern bool TempTablespacesAreSet(void); extern int GetTempTablespaces(Oid *tableSpaces, int numSpaces); extern Oid GetNextTempTableSpace(void); extern void AtEOXact_Files(bool isCommit); extern void AtEOSubXact_Files(bool isCommit, SubTransactionId mySubid, SubTransactionId parentSubid); extern void RemovePgTempFiles(void); extern void RemovePgTempFilesInDir(const char *tmpdirname, bool missing_ok, bool unlink_all); extern bool looks_like_temp_rel_name(const char *name); extern int pg_fsync(int fd); extern int pg_fsync_no_writethrough(int fd); extern int pg_fsync_writethrough(int fd); extern int pg_fdatasync(int fd); extern bool pg_file_exists(const char *name); extern void pg_flush_data(int fd, pgoff_t offset, pgoff_t nbytes); extern int pg_truncate(const char *path, pgoff_t length); extern void fsync_fname(const char *fname, bool isdir); extern int fsync_fname_ext(const char *fname, bool isdir, bool ignore_perm, int elevel); extern int durable_rename(const char *oldfile, const char *newfile, int elevel); extern int durable_unlink(const char *fname, int elevel); extern void SyncDataDirectory(void); extern int data_sync_elevel(int elevel); static inline ssize_t FileRead(File file, void *buffer, size_t amount, pgoff_t offset, uint32 wait_event_info) { struct iovec iov = { .iov_base = buffer, .iov_len = amount }; return FileReadV(file, &iov, 1, offset, wait_event_info); } static inline ssize_t FileWrite(File file, const void *buffer, size_t amount, pgoff_t offset, uint32 wait_event_info) { struct iovec iov = { .iov_base = unconstify(void *, buffer), .iov_len = amount }; return FileWriteV(file, &iov, 1, offset, wait_event_info); } #endif /* FD_H */