From d28b74e4bca1ab7fe54ddf4593f5b533bb436b68 Mon Sep 17 00:00:00 2001
From: rswindell <>
Date: Wed, 14 Aug 2019 05:59:30 +0000
Subject: [PATCH] Use "Open file description locks" when available (i.e. Linux
3.15 and later) This variation on fcntl() record-locks resolves
multiple-thread / forking issue with region locks. No longer falls back to
using flock() (whole-file locks), when OFD locks are available and used
successfully. At the least, this should provide a performance boost for
shared files using region locks (on Linux). No change for Windows (region
locks already worked sanely among multiple threads) and other *nixes (that
use POSIX fcntl() locks only).
---
src/xpdev/filewrap.c | 38 ++++++++++++++++++++++++++++++--------
1 file changed, 30 insertions(+), 8 deletions(-)
diff --git a/src/xpdev/filewrap.c b/src/xpdev/filewrap.c
index 4e9c91d061..2ebbb74c8f 100644
--- a/src/xpdev/filewrap.c
+++ b/src/xpdev/filewrap.c
@@ -90,7 +90,11 @@ off_t DLLCALL filelength(int fd)
int DLLCALL lock(int fd, off_t pos, off_t len)
{
#if defined(F_SANERDLCKNO) || !defined(BSD)
- struct flock alock;
+ struct flock alock = {0};
+ int cmd = F_SETLK;
+ #ifdef F_OFD_SETLK
+ cmd = F_OFD_SETLK;
+ #endif
#ifndef F_SANEWRLCKNO
int flags;
@@ -107,8 +111,13 @@ int DLLCALL lock(int fd, off_t pos, off_t len)
alock.l_start = pos;
alock.l_len = (int)len;
- if(fcntl(fd, F_SETLK, &alock)==-1 && errno != EINVAL)
- return(-1);
+ int result = fcntl(fd, cmd, &alock);
+ if(result == -1 && errno != EINVAL)
+ return -1;
+ #ifdef F_OFD_SETLK
+ if(result == 0)
+ return 0;
+ #endif
#endif
#if !defined(F_SANEWRLCKNO) && !defined(__QNX__) && !defined(__solaris__)
@@ -125,7 +134,11 @@ int DLLCALL unlock(int fd, off_t pos, off_t len)
{
#if defined(F_SANEUNLCK) || !defined(BSD)
- struct flock alock;
+ struct flock alock = {0};
+ int cmd = F_SETLK;
+#ifdef F_OFD_SETLK
+ cmd = F_OFD_SETLK;
+#endif
#ifdef F_SANEUNLCK
alock.l_type = F_SANEUNLCK; /* remove the lock */
#else
@@ -134,8 +147,13 @@ int DLLCALL unlock(int fd, off_t pos, off_t len)
alock.l_whence = L_SET;
alock.l_start = pos;
alock.l_len = (int)len;
- if(fcntl(fd, F_SETLK, &alock)==-1 && errno != EINVAL)
- return(-1);
+ int result = fcntl(fd, cmd, &alock);
+ if(result == -1 && errno != EINVAL)
+ return -1;
+#ifdef F_OFD_SETLK
+ if(result == 0)
+ return 0;
+#endif
#endif
#if !defined(F_SANEUNLCK) && !defined(__QNX__) && !defined(__solaris__)
@@ -192,7 +210,7 @@ int DLLCALL sopen(const char *fn, int sh_access, int share, ...)
int flock_op=LOCK_NB; /* non-blocking */
#endif
#if defined(F_SANEWRLCKNO) || !defined(BSD)
- struct flock alock;
+ struct flock alock = {0};
#endif
va_list ap;
@@ -208,13 +226,17 @@ int DLLCALL sopen(const char *fn, int sh_access, int share, ...)
if (share == SH_DENYNO || share == SH_COMPAT) /* no lock needed */
return fd;
#if defined(F_SANEWRLCKNO) || !defined(BSD)
+ int cmd = F_SETLK;
+#ifdef F_OFD_SETLK
+ cmd = F_OFD_SETLK;
+#endif
/* use fcntl (doesn't work correctly with threads) */
alock.l_type = share;
alock.l_whence = L_SET;
alock.l_start = 0;
alock.l_len = 0; /* lock to EOF */
- if(fcntl(fd, F_SETLK, &alock)==-1 && errno != EINVAL) { /* EINVAL means the file does not support locking */
+ if(fcntl(fd, cmd, &alock)==-1 && errno != EINVAL) { /* EINVAL means the file does not support locking */
close(fd);
return -1;
}
--
GitLab