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Commit cb87f01

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dmpgprodmpgpro
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Merge commit '733cf3719583b1802c7177309cdb41b3b842d658' into PGPRO9_6
2 parents 0249fb4 + 733cf37 commit cb87f01

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16 files changed

+422
-258
lines changed

16 files changed

+422
-258
lines changed

‎contrib/pg_probackup/backup.c

Lines changed: 3 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -2,7 +2,8 @@
22
*
33
* backup.c: backup DB cluster, archived WAL
44
*
5-
* Copyright (c) 2009-2013, NIPPON TELEGRAPH AND TELEPHONE CORPORATION
5+
* Portions Copyright (c) 2009-2013, NIPPON TELEGRAPH AND TELEPHONE CORPORATION
6+
* Portions Copyright (c) 2015-2017, Postgres Professional
67
*
78
*-------------------------------------------------------------------------
89
*/
@@ -403,7 +404,6 @@ do_backup_database(parray *backup_list, bool smooth_checkpoint)
403404
int
404405
do_backup(bool smooth_checkpoint)
405406
{
406-
int ret;
407407
parray *backup_list;
408408
parray *files_database;
409409

@@ -432,12 +432,7 @@ do_backup(bool smooth_checkpoint)
432432
elog(LOG, "----------------------------------------");
433433

434434
/* get exclusive lock of backup catalog */
435-
ret = catalog_lock(true);
436-
if (ret == -1)
437-
elog(ERROR, "cannot lock backup catalog");
438-
else if (ret == 1)
439-
elog(ERROR,
440-
"another pg_probackup is running, skipping this backup");
435+
catalog_lock(true);
441436

442437
/* initialize backup result */
443438
current.status = BACKUP_STATUS_RUNNING;
@@ -508,9 +503,6 @@ do_backup(bool smooth_checkpoint)
508503

509504
pgBackupValidate(&current, false, false);
510505

511-
/* release catalog lock */
512-
catalog_unlock();
513-
514506
return 0;
515507
}
516508

‎contrib/pg_probackup/catalog.c

Lines changed: 169 additions & 34 deletions
Original file line numberDiff line numberDiff line change
@@ -2,7 +2,8 @@
22
*
33
* catalog.c: backup catalog opration
44
*
5-
* Copyright (c) 2009-2011, NIPPON TELEGRAPH AND TELEPHONE CORPORATION
5+
* Portions Copyright (c) 2009-2011, NIPPON TELEGRAPH AND TELEPHONE CORPORATION
6+
* Portions Copyright (c) 2015-2017, Postgres Professional
67
*
78
*-------------------------------------------------------------------------
89
*/
@@ -12,6 +13,7 @@
1213
#include <dirent.h>
1314
#include <fcntl.h>
1415
#include <libgen.h>
16+
#include <signal.h>
1517
#include <sys/file.h>
1618
#include <sys/stat.h>
1719
#include <sys/types.h>
@@ -25,42 +27,185 @@ static pgBackup *read_backup_from_file(const char *path);
2527

2628
#define BOOL_TO_STR(val) ((val) ? "true" : "false")
2729

28-
static int lock_fd = -1;
30+
static bool exit_hook_registered = false;
31+
static char lock_file[MAXPGPATH];
32+
33+
static void
34+
unlink_lock_atexit(void)
35+
{
36+
int res;
37+
res = unlink(lock_file);
38+
if (res != 0 && res != ENOENT)
39+
elog(WARNING, "%s: %s", lock_file, strerror(errno));
40+
}
2941

3042
/*
31-
* Lock of the catalog with pg_probackup.conf file and return 0.
32-
* If the lock is held by another one, return 1 immediately.
43+
* Create a lockfile.
3344
*/
3445
int
3546
catalog_lock(bool check_catalog)
3647
{
37-
int ret;
38-
char id_path[MAXPGPATH];
39-
40-
join_path_components(id_path, backup_path, BACKUP_CATALOG_CONF_FILE);
41-
lock_fd = open(id_path, O_RDWR);
42-
if (lock_fd == -1)
43-
elog(errno == ENOENT ? ERROR : ERROR,
44-
"cannot open file \"%s\": %s", id_path, strerror(errno));
45-
#ifdef __IBMC__
46-
ret = lockf(lock_fd, LOCK_EX | LOCK_NB, 0); /* non-blocking */
48+
int fd;
49+
char buffer[MAXPGPATH * 2 + 256];
50+
int ntries;
51+
int len;
52+
int encoded_pid;
53+
pid_t my_pid,
54+
my_p_pid;
55+
56+
join_path_components(lock_file, backup_path, BACKUP_CATALOG_PID);
57+
58+
/*
59+
* If the PID in the lockfile is our own PID or our parent's or
60+
* grandparent's PID, then the file must be stale (probably left over from
61+
* a previous system boot cycle). We need to check this because of the
62+
* likelihood that a reboot will assign exactly the same PID as we had in
63+
* the previous reboot, or one that's only one or two counts larger and
64+
* hence the lockfile's PID now refers to an ancestor shell process. We
65+
* allow pg_ctl to pass down its parent shell PID (our grandparent PID)
66+
* via the environment variable PG_GRANDPARENT_PID; this is so that
67+
* launching the postmaster via pg_ctl can be just as reliable as
68+
* launching it directly. There is no provision for detecting
69+
* further-removed ancestor processes, but if the init script is written
70+
* carefully then all but the immediate parent shell will be root-owned
71+
* processes and so the kill test will fail with EPERM. Note that we
72+
* cannot get a false negative this way, because an existing postmaster
73+
* would surely never launch a competing postmaster or pg_ctl process
74+
* directly.
75+
*/
76+
my_pid = getpid();
77+
#ifndef WIN32
78+
my_p_pid = getppid();
4779
#else
48-
ret = flock(lock_fd, LOCK_EX | LOCK_NB); /* non-blocking */
80+
81+
/*
82+
* Windows hasn't got getppid(), but doesn't need it since it's not using
83+
* real kill() either...
84+
*/
85+
my_p_pid = 0;
4986
#endif
50-
if (ret == -1)
87+
88+
/*
89+
* We need a loop here because of race conditions. But don't loop forever
90+
* (for example, a non-writable $backup_path directory might cause a failure
91+
* that won't go away). 100 tries seems like plenty.
92+
*/
93+
for (ntries = 0;; ntries++)
5194
{
52-
if (errno == EWOULDBLOCK)
95+
/*
96+
* Try to create the lock file --- O_EXCL makes this atomic.
97+
*
98+
* Think not to make the file protection weaker than 0600. See
99+
* comments below.
100+
*/
101+
fd = open(lock_file, O_RDWR | O_CREAT | O_EXCL, 0600);
102+
if (fd >= 0)
103+
break; /* Success; exit the retry loop */
104+
105+
/*
106+
* Couldn't create the pid file. Probably it already exists.
107+
*/
108+
if ((errno != EEXIST && errno != EACCES) || ntries > 100)
109+
elog(ERROR, "could not create lock file \"%s\": %s",
110+
lock_file, strerror(errno));
111+
112+
/*
113+
* Read the file to get the old owner's PID. Note race condition
114+
* here: file might have been deleted since we tried to create it.
115+
*/
116+
fd = open(lock_file, O_RDONLY, 0600);
117+
if (fd < 0)
53118
{
54-
close(lock_fd);
55-
return 1;
119+
if (errno == ENOENT)
120+
continue; /* race condition; try again */
121+
elog(ERROR, "could not open lock file \"%s\": %s",
122+
lock_file, strerror(errno));
56123
}
57-
else
124+
if ((len = read(fd, buffer, sizeof(buffer) - 1)) < 0)
125+
elog(ERROR, "could not read lock file \"%s\": %s",
126+
lock_file, strerror(errno));
127+
close(fd);
128+
129+
if (len == 0)
130+
elog(ERROR, "lock file \"%s\" is empty", lock_file);
131+
132+
buffer[len] = '\0';
133+
encoded_pid = atoi(buffer);
134+
135+
if (encoded_pid <= 0)
136+
elog(ERROR, "bogus data in lock file \"%s\": \"%s\"",
137+
lock_file, buffer);
138+
139+
/*
140+
* Check to see if the other process still exists
141+
*
142+
* Per discussion above, my_pid, my_p_pid can be
143+
* ignored as false matches.
144+
*
145+
* Normally kill() will fail with ESRCH if the given PID doesn't
146+
* exist.
147+
*/
148+
if (encoded_pid != my_pid && encoded_pid != my_p_pid)
58149
{
59-
int errno_tmp = errno;
60-
close(lock_fd);
61-
elog(ERROR, "cannot lock file \"%s\": %s", id_path,
62-
strerror(errno_tmp));
150+
if (kill(encoded_pid, 0) == 0 ||
151+
(errno != ESRCH && errno != EPERM))
152+
elog(ERROR, "lock file \"%s\" already exists", lock_file);
63153
}
154+
155+
/*
156+
* Looks like nobody's home. Unlink the file and try again to create
157+
* it. Need a loop because of possible race condition against other
158+
* would-be creators.
159+
*/
160+
if (unlink(lock_file) < 0)
161+
elog(ERROR, "could not remove old lock file \"%s\": %s",
162+
lock_file, strerror(errno));
163+
}
164+
165+
/*
166+
* Successfully created the file, now fill it.
167+
*/
168+
snprintf(buffer, sizeof(buffer), "%d\n", my_pid);
169+
170+
errno = 0;
171+
if (write(fd, buffer, strlen(buffer)) != strlen(buffer))
172+
{
173+
int save_errno = errno;
174+
175+
close(fd);
176+
unlink(lock_file);
177+
/* if write didn't set errno, assume problem is no disk space */
178+
errno = save_errno ? save_errno : ENOSPC;
179+
elog(ERROR, "could not write lock file \"%s\": %s",
180+
lock_file, strerror(errno));
181+
}
182+
if (fsync(fd) != 0)
183+
{
184+
int save_errno = errno;
185+
186+
close(fd);
187+
unlink(lock_file);
188+
errno = save_errno;
189+
elog(ERROR, "could not write lock file \"%s\": %s",
190+
lock_file, strerror(errno));
191+
}
192+
if (close(fd) != 0)
193+
{
194+
int save_errno = errno;
195+
196+
unlink(lock_file);
197+
errno = save_errno;
198+
elog(ERROR, "could not write lock file \"%s\": %s",
199+
lock_file, strerror(errno));
200+
}
201+
202+
/*
203+
* Arrange to unlink the lock file(s) at proc_exit.
204+
*/
205+
if (!exit_hook_registered)
206+
{
207+
atexit(unlink_lock_atexit);
208+
exit_hook_registered = true;
64209
}
65210

66211
if (check_catalog)
@@ -79,16 +224,6 @@ catalog_lock(bool check_catalog)
79224
return 0;
80225
}
81226

82-
/*
83-
* Release catalog lock.
84-
*/
85-
void
86-
catalog_unlock(void)
87-
{
88-
close(lock_fd);
89-
lock_fd = -1;
90-
}
91-
92227
/*
93228
* Create a pgBackup which taken at timestamp.
94229
* If no backup matches, return NULL.

‎contrib/pg_probackup/data.c

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -2,7 +2,8 @@
22
*
33
* data.c: data parsing pages
44
*
5-
* Copyright (c) 2009-2013, NIPPON TELEGRAPH AND TELEPHONE CORPORATION
5+
* Portions Copyright (c) 2009-2013, NIPPON TELEGRAPH AND TELEPHONE CORPORATION
6+
* Portions Copyright (c) 2015-2017, Postgres Professional
67
*
78
*-------------------------------------------------------------------------
89
*/

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