unix.c: use posix_fallocate() (#409)

Using of posix_fallocate() guarantees that, if it succeed, the attempting to write to allocated space range does not fail because of lack of storage space. This prevents SIGBUS when trying to write to mmaped file and no space left. Co-Authored-by: Ivan Zakharyaschev <[email protected]> Reported-by: Mikhail Kulagin <m.kulagin at postgrespro dot ru> Co-authored-by: Ivan Zakharyaschev <[email protected]>
ClusterLabs · Jul 29, 2020 · 1c6229c · 1c6229c
1 parent caec56b
commit 1c6229c
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Showing 2 changed files with 13 additions and 1 deletion.
diff --git a/configure.ac b/configure.ac
@@ -259,7 +259,7 @@ AC_FUNC_CHOWN
 AC_FUNC_FORK
 AC_FUNC_MMAP
 AC_FUNC_STRERROR_R
-AC_CHECK_FUNCS([alarm fsync fdatasync ftruncate \
+AC_CHECK_FUNCS([alarm fsync fdatasync ftruncate posix_fallocate \
 		gettimeofday localtime localtime_r \
 		memset munmap socket \
 		strchr strrchr strdup strstr strcasecmp \

diff --git a/lib/unix.c b/lib/unix.c
@@ -26,6 +26,9 @@
 #ifdef HAVE_SYS_MMAN_H
 #include <sys/mman.h>
 #endif
+#if defined(HAVE_FCNTL_H) && defined(HAVE_POSIX_FALLOCATE)
+#include <fcntl.h>
+#endif
 
 #include "util_int.h"
 #include <qb/qbdefs.h>
@@ -112,6 +115,14 @@ qb_sys_mmap_file_open(char *path, const char *file, size_t bytes,
 		goto unlink_exit;
 	}
 
+#ifdef HAVE_POSIX_FALLOCATE
+	if ((res = posix_fallocate(fd, 0, bytes)) != 0) {
+		errno = res;
+		res = -1 * res;
+		qb_util_perror(LOG_ERR, "couldn't allocate file %s", path);
+		goto unlink_exit;
+	}
+#else
 	if (file_flags & O_CREAT) {
 		long page_size = sysconf(_SC_PAGESIZE);
 		long write_size = QB_MIN(page_size, bytes);
@@ -138,6 +149,7 @@ qb_sys_mmap_file_open(char *path, const char *file, size_t bytes,
 		}
 		free(buffer);
 	}
+#endif /* HAVE_POSIX_FALLOCATE */
 
 	return fd;