Move fsync routines of initdb into src/common/

The intention is to used those in other utilities such as pg_basebackup
and pg_receivexlog.

From: Michael Paquier <michael.paquier@gmail.com>
This commit is contained in:
Peter Eisentraut 2016-09-29 12:00:00 -04:00
parent 6e654546fb
commit bf5bb2e85b
7 changed files with 313 additions and 263 deletions

View File

@ -61,6 +61,7 @@
#endif
#include "catalog/catalog.h"
#include "common/file_utils.h"
#include "common/restricted_token.h"
#include "common/username.h"
#include "mb/pg_wchar.h"
@ -70,13 +71,6 @@
#include "fe_utils/string_utils.h"
/* Define PG_FLUSH_DATA_WORKS if we have an implementation for pg_flush_data */
#if defined(HAVE_SYNC_FILE_RANGE)
#define PG_FLUSH_DATA_WORKS 1
#elif defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_DONTNEED)
#define PG_FLUSH_DATA_WORKS 1
#endif
/* Ideally this would be in a .h file, but it hardly seems worth the trouble */
extern const char *select_default_timezone(const char *share_path);
@ -237,13 +231,6 @@ static char **filter_lines_with_token(char **lines, const char *token);
#endif
static char **readfile(const char *path);
static void writefile(char *path, char **lines);
static void walkdir(const char *path,
void (*action) (const char *fname, bool isdir),
bool process_symlinks);
#ifdef PG_FLUSH_DATA_WORKS
static void pre_sync_fname(const char *fname, bool isdir);
#endif
static void fsync_fname_ext(const char *fname, bool isdir);
static FILE *popen_check(const char *command, const char *mode);
static void exit_nicely(void);
static char *get_id(void);
@ -270,7 +257,6 @@ static void load_plpgsql(FILE *cmdfd);
static void vacuum_db(FILE *cmdfd);
static void make_template0(FILE *cmdfd);
static void make_postgres(FILE *cmdfd);
static void fsync_pgdata(void);
static void trapsig(int signum);
static void check_ok(void);
static char *escape_quotes(const char *src);
@ -528,177 +514,6 @@ writefile(char *path, char **lines)
}
}
/*
* 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 but not considered fatal.
*
* See also walkdir in fd.c, which is a backend version of this logic.
*/
static void
walkdir(const char *path,
void (*action) (const char *fname, bool isdir),
bool process_symlinks)
{
DIR *dir;
struct dirent *de;
dir = opendir(path);
if (dir == NULL)
{
fprintf(stderr, _("%s: could not open directory \"%s\": %s\n"),
progname, path, strerror(errno));
return;
}
while (errno = 0, (de = readdir(dir)) != NULL)
{
char subpath[MAXPGPATH];
struct stat fst;
int sret;
if (strcmp(de->d_name, ".") == 0 ||
strcmp(de->d_name, "..") == 0)
continue;
snprintf(subpath, MAXPGPATH, "%s/%s", path, de->d_name);
if (process_symlinks)
sret = stat(subpath, &fst);
else
sret = lstat(subpath, &fst);
if (sret < 0)
{
fprintf(stderr, _("%s: could not stat file \"%s\": %s\n"),
progname, subpath, strerror(errno));
continue;
}
if (S_ISREG(fst.st_mode))
(*action) (subpath, false);
else if (S_ISDIR(fst.st_mode))
walkdir(subpath, action, false);
}
if (errno)
fprintf(stderr, _("%s: could not read directory \"%s\": %s\n"),
progname, path, strerror(errno));
(void) closedir(dir);
/*
* 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. Recent versions of ext4 have made the window much wider but
* it's been an issue for ext3 and other filesystems in the past.
*/
(*action) (path, true);
}
/*
* Hint to the OS that it should get ready to fsync() this file.
*
* Ignores errors trying to open unreadable files, and reports other errors
* non-fatally.
*/
#ifdef PG_FLUSH_DATA_WORKS
static void
pre_sync_fname(const char *fname, bool isdir)
{
int fd;
fd = open(fname, O_RDONLY | PG_BINARY);
if (fd < 0)
{
if (errno == EACCES || (isdir && errno == EISDIR))
return;
fprintf(stderr, _("%s: could not open file \"%s\": %s\n"),
progname, fname, strerror(errno));
return;
}
/*
* We do what pg_flush_data() would do in the backend: prefer to use
* sync_file_range, but fall back to posix_fadvise. We ignore errors
* because this is only a hint.
*/
#if defined(HAVE_SYNC_FILE_RANGE)
(void) sync_file_range(fd, 0, 0, SYNC_FILE_RANGE_WRITE);
#elif defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_DONTNEED)
(void) posix_fadvise(fd, 0, 0, POSIX_FADV_DONTNEED);
#else
#error PG_FLUSH_DATA_WORKS should not have been defined
#endif
(void) close(fd);
}
#endif /* PG_FLUSH_DATA_WORKS */
/*
* fsync_fname_ext -- Try to fsync a file or directory
*
* Ignores errors trying to open unreadable files, or trying to fsync
* directories on systems where that isn't allowed/required. Reports
* other errors non-fatally.
*/
static void
fsync_fname_ext(const char *fname, bool isdir)
{
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;
/*
* Open the file, silently ignoring errors about unreadable files (or
* unsupported operations, e.g. opening a directory under Windows), and
* logging others.
*/
fd = open(fname, flags);
if (fd < 0)
{
if (errno == EACCES || (isdir && errno == EISDIR))
return;
fprintf(stderr, _("%s: could not open file \"%s\": %s\n"),
progname, fname, strerror(errno));
return;
}
returncode = fsync(fd);
/*
* Some OSes don't allow us to fsync directories at all, so we can ignore
* those errors. Anything else needs to be reported.
*/
if (returncode != 0 && !(isdir && errno == EBADF))
fprintf(stderr, _("%s: could not fsync file \"%s\": %s\n"),
progname, fname, strerror(errno));
(void) close(fd);
}
/*
* Open a subcommand with suitable error messaging
*/
@ -2276,77 +2091,6 @@ make_postgres(FILE *cmdfd)
PG_CMD_PUTS(*line);
}
/*
* 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_xlog 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 reported but not considered fatal.
*/
static void
fsync_pgdata(void)
{
bool xlog_is_symlink;
char pg_xlog[MAXPGPATH];
char pg_tblspc[MAXPGPATH];
fputs(_("syncing data to disk ... "), stdout);
fflush(stdout);
snprintf(pg_xlog, MAXPGPATH, "%s/pg_xlog", pg_data);
snprintf(pg_tblspc, MAXPGPATH, "%s/pg_tblspc", pg_data);
/*
* If pg_xlog 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_xlog, &st) < 0)
fprintf(stderr, _("%s: could not stat file \"%s\": %s\n"),
progname, pg_xlog, strerror(errno));
else if (S_ISLNK(st.st_mode))
xlog_is_symlink = true;
}
#else
if (pgwin32_is_junction(pg_xlog))
xlog_is_symlink = true;
#endif
/*
* If possible, hint to the kernel that we're soon going to fsync the data
* directory and its contents.
*/
#ifdef PG_FLUSH_DATA_WORKS
walkdir(pg_data, pre_sync_fname, false);
if (xlog_is_symlink)
walkdir(pg_xlog, pre_sync_fname, false);
walkdir(pg_tblspc, pre_sync_fname, true);
#endif
/*
* Now we do the fsync()s in the same order.
*
* The main call ignores symlinks, so in addition to specially processing
* pg_xlog 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(pg_data, fsync_fname_ext, false);
if (xlog_is_symlink)
walkdir(pg_xlog, fsync_fname_ext, false);
walkdir(pg_tblspc, fsync_fname_ext, true);
check_ok();
}
/*
@ -3512,7 +3256,10 @@ main(int argc, char *argv[])
exit_nicely();
}
fsync_pgdata();
fputs(_("syncing data to disk ... "), stdout);
fflush(stdout);
fsync_pgdata(pg_data, progname);
check_ok();
return 0;
}
@ -3574,7 +3321,12 @@ main(int argc, char *argv[])
initialize_data_directory();
if (do_sync)
fsync_pgdata();
{
fputs(_("syncing data to disk ... "), stdout);
fflush(stdout);
fsync_pgdata(pg_data, progname);
check_ok();
}
else
printf(_("\nSync to disk skipped.\nThe data directory might become corrupt if the operating system crashes.\n"));

View File

@ -1,5 +1,5 @@
# src/bin/initdb/nls.mk
CATALOG_NAME = initdb
AVAIL_LANGUAGES = cs de es fr it ja ko pl pt_BR ru sv zh_CN
GETTEXT_FILES = findtimezone.c initdb.c ../../common/exec.c ../../common/fe_memutils.c ../../common/pgfnames.c ../../common/restricted_token.c ../../common/rmtree.c ../../common/username.c ../../common/wait_error.c ../../port/dirmod.c
GETTEXT_FILES = findtimezone.c initdb.c ../../common/exec.c ../../common/fe_memutils.c ../../common/file_utils.c ../../common/pgfnames.c ../../common/restricted_token.c ../../common/rmtree.c ../../common/username.c ../../common/wait_error.c ../../port/dirmod.c
GETTEXT_TRIGGERS = simple_prompt

View File

@ -1,5 +1,5 @@
# src/bin/pg_basebackup/nls.mk
CATALOG_NAME = pg_basebackup
AVAIL_LANGUAGES = de es fr it ko pl pt_BR ru zh_CN
GETTEXT_FILES = pg_basebackup.c pg_receivexlog.c pg_recvlogical.c receivelog.c streamutil.c ../../common/fe_memutils.c
GETTEXT_FILES = pg_basebackup.c pg_receivexlog.c pg_recvlogical.c receivelog.c streamutil.c ../../common/fe_memutils.c ../../common/file_utils.c
GETTEXT_TRIGGERS = simple_prompt

View File

@ -44,7 +44,7 @@ OBJS_COMMON = config_info.o controldata_utils.o exec.o ip.o keywords.o \
md5.o pg_lzcompress.o pgfnames.o psprintf.o relpath.o rmtree.o \
string.o username.o wait_error.o
OBJS_FRONTEND = $(OBJS_COMMON) fe_memutils.o restricted_token.o
OBJS_FRONTEND = $(OBJS_COMMON) fe_memutils.o file_utils.o restricted_token.o
OBJS_SRV = $(OBJS_COMMON:%.o=%_srv.o)

276
src/common/file_utils.c Normal file
View File

@ -0,0 +1,276 @@
/*-------------------------------------------------------------------------
*
* File-processing utility routines.
*
* Assorted utility functions to work on files.
*
*
* Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/common/file_utils.c
*
*-------------------------------------------------------------------------
*/
#include "postgres_fe.h"
#include <dirent.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>
#include "common/file_utils.h"
/* Define PG_FLUSH_DATA_WORKS if we have an implementation for pg_flush_data */
#if defined(HAVE_SYNC_FILE_RANGE)
#define PG_FLUSH_DATA_WORKS 1
#elif defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_DONTNEED)
#define PG_FLUSH_DATA_WORKS 1
#endif
#ifdef PG_FLUSH_DATA_WORKS
static void pre_sync_fname(const char *fname, bool isdir,
const char *progname);
#endif
static void walkdir(const char *path,
void (*action) (const char *fname, bool isdir, const char *progname),
bool process_symlinks, const char *progname);
/*
* 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_xlog 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 reported but not considered fatal.
*/
void
fsync_pgdata(const char *pg_data, const char *progname)
{
bool xlog_is_symlink;
char pg_xlog[MAXPGPATH];
char pg_tblspc[MAXPGPATH];
snprintf(pg_xlog, MAXPGPATH, "%s/pg_xlog", pg_data);
snprintf(pg_tblspc, MAXPGPATH, "%s/pg_tblspc", pg_data);
/*
* If pg_xlog 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_xlog, &st) < 0)
fprintf(stderr, _("%s: could not stat file \"%s\": %s\n"),
progname, pg_xlog, strerror(errno));
else if (S_ISLNK(st.st_mode))
xlog_is_symlink = true;
}
#else
if (pgwin32_is_junction(pg_xlog))
xlog_is_symlink = true;
#endif
/*
* If possible, hint to the kernel that we're soon going to fsync the data
* directory and its contents.
*/
#ifdef PG_FLUSH_DATA_WORKS
walkdir(pg_data, pre_sync_fname, false, progname);
if (xlog_is_symlink)
walkdir(pg_xlog, pre_sync_fname, false, progname);
walkdir(pg_tblspc, pre_sync_fname, true, progname);
#endif
/*
* Now we do the fsync()s in the same order.
*
* The main call ignores symlinks, so in addition to specially processing
* pg_xlog 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(pg_data, fsync_fname, false, progname);
if (xlog_is_symlink)
walkdir(pg_xlog, fsync_fname, false, progname);
walkdir(pg_tblspc, fsync_fname, true, progname);
}
/*
* 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 but not considered fatal.
*
* See also walkdir in fd.c, which is a backend version of this logic.
*/
static void
walkdir(const char *path,
void (*action) (const char *fname, bool isdir, const char *progname),
bool process_symlinks, const char *progname)
{
DIR *dir;
struct dirent *de;
dir = opendir(path);
if (dir == NULL)
{
fprintf(stderr, _("%s: could not open directory \"%s\": %s\n"),
progname, path, strerror(errno));
return;
}
while (errno = 0, (de = readdir(dir)) != NULL)
{
char subpath[MAXPGPATH];
struct stat fst;
int sret;
if (strcmp(de->d_name, ".") == 0 ||
strcmp(de->d_name, "..") == 0)
continue;
snprintf(subpath, MAXPGPATH, "%s/%s", path, de->d_name);
if (process_symlinks)
sret = stat(subpath, &fst);
else
sret = lstat(subpath, &fst);
if (sret < 0)
{
fprintf(stderr, _("%s: could not stat file \"%s\": %s\n"),
progname, subpath, strerror(errno));
continue;
}
if (S_ISREG(fst.st_mode))
(*action) (subpath, false, progname);
else if (S_ISDIR(fst.st_mode))
walkdir(subpath, action, false, progname);
}
if (errno)
fprintf(stderr, _("%s: could not read directory \"%s\": %s\n"),
progname, path, strerror(errno));
(void) closedir(dir);
/*
* 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. Recent versions of ext4 have made the window much wider but
* it's been an issue for ext3 and other filesystems in the past.
*/
(*action) (path, true, progname);
}
/*
* Hint to the OS that it should get ready to fsync() this file.
*
* Ignores errors trying to open unreadable files, and reports other errors
* non-fatally.
*/
#ifdef PG_FLUSH_DATA_WORKS
static void
pre_sync_fname(const char *fname, bool isdir, const char *progname)
{
int fd;
fd = open(fname, O_RDONLY | PG_BINARY);
if (fd < 0)
{
if (errno == EACCES || (isdir && errno == EISDIR))
return;
fprintf(stderr, _("%s: could not open file \"%s\": %s\n"),
progname, fname, strerror(errno));
return;
}
/*
* We do what pg_flush_data() would do in the backend: prefer to use
* sync_file_range, but fall back to posix_fadvise. We ignore errors
* because this is only a hint.
*/
#if defined(HAVE_SYNC_FILE_RANGE)
(void) sync_file_range(fd, 0, 0, SYNC_FILE_RANGE_WRITE);
#elif defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_DONTNEED)
(void) posix_fadvise(fd, 0, 0, POSIX_FADV_DONTNEED);
#else
#error PG_FLUSH_DATA_WORKS should not have been defined
#endif
(void) close(fd);
}
#endif /* PG_FLUSH_DATA_WORKS */
/*
* fsync_fname -- Try to fsync a file or directory
*
* Ignores errors trying to open unreadable files, or trying to fsync
* directories on systems where that isn't allowed/required. Reports
* other errors non-fatally.
*/
void
fsync_fname(const char *fname, bool isdir, const char *progname)
{
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;
/*
* Open the file, silently ignoring errors about unreadable files (or
* unsupported operations, e.g. opening a directory under Windows), and
* logging others.
*/
fd = open(fname, flags);
if (fd < 0)
{
if (errno == EACCES || (isdir && errno == EISDIR))
return;
fprintf(stderr, _("%s: could not open file \"%s\": %s\n"),
progname, fname, strerror(errno));
return;
}
returncode = fsync(fd);
/*
* Some OSes don't allow us to fsync directories at all, so we can ignore
* those errors. Anything else needs to be reported.
*/
if (returncode != 0 && !(isdir && errno == EBADF))
fprintf(stderr, _("%s: could not fsync file \"%s\": %s\n"),
progname, fname, strerror(errno));
(void) close(fd);
}

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@ -0,0 +1,22 @@
/*-------------------------------------------------------------------------
*
* File-processing utility routines for frontend code
*
* Assorted utility functions to work on files.
*
*
* Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/common/file_utils.h
*
*-------------------------------------------------------------------------
*/
#ifndef FILE_UTILS_H
#define FILE_UTILS_H
extern void fsync_fname(const char *fname, bool isdir,
const char *progname);
extern void fsync_pgdata(const char *pg_data, const char *progname);
#endif /* FILE_UTILS_H */

View File

@ -115,7 +115,7 @@ sub mkvcbuild
string.c username.c wait_error.c);
our @pgcommonfrontendfiles = (
@pgcommonallfiles, qw(fe_memutils.c
@pgcommonallfiles, qw(fe_memutils.c file_utils.c
restricted_token.c));
our @pgcommonbkndfiles = @pgcommonallfiles;