From 34a61b6c9eed3fad360066fb63132ebc7e0aaaa6 Mon Sep 17 00:00:00 2001
From: Khem Raj <raj.khem@gmail.com>
Date: Fri, 20 Feb 2015 05:12:48 +0000
Subject: [PATCH 06/11] journal: Use posix fallocate only if available

Some architecture ports in uclibc did not support it in past

Upstream-Status: Denied [no desire for uclibc support]

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
---
 src/journal/journal-file.c  | 16 +++++++++++++++-
 src/journal/journald-kmsg.c | 15 ++++++++++++++-
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/src/journal/journal-file.c b/src/journal/journal-file.c
index 2845e05..9431171 100644
--- a/src/journal/journal-file.c
+++ b/src/journal/journal-file.c
@@ -36,6 +36,8 @@
 #include "compress.h"
 #include "fsprg.h"
 
+#include "config.h"
+
 #define DEFAULT_DATA_HASH_TABLE_SIZE (2047ULL*sizeof(HashItem))
 #define DEFAULT_FIELD_HASH_TABLE_SIZE (333ULL*sizeof(HashItem))
 
@@ -354,7 +356,7 @@ static int journal_file_fstat(JournalFile *f) {
 
 static int journal_file_allocate(JournalFile *f, uint64_t offset, uint64_t size) {
         uint64_t old_size, new_size;
-        int r;
+        int r = 0;
 
         assert(f);
 
@@ -418,9 +420,21 @@ static int journal_file_allocate(JournalFile *f, uint64_t offset, uint64_t size)
         /* Note that the glibc fallocate() fallback is very
            inefficient, hence we try to minimize the allocation area
            as we can. */
+#ifdef HAVE_POSIX_FALLOCATE
         r = posix_fallocate(f->fd, old_size, new_size - old_size);
         if (r != 0)
                 return -r;
+#else
+        /* Write something every 512 bytes to make sure the block is allocated */
+        uint64_t len = new_size - old_size;
+        uint64_t offset = old_size;
+        for (offset += (len-1) % 512; len > 0; offset += 512) {
+                len -= 512;
+                if (pwrite(f->fd, "", 1, offset) != 1)
+                        return -errno;
+        }
+
+#endif /* HAVE_POSIX_FALLOCATE */
 
         f->header->arena_size = htole64(new_size - le64toh(f->header->header_size));
 
diff --git a/src/journal/journald-kmsg.c b/src/journal/journald-kmsg.c
index c4216c4..a998ed5 100644
--- a/src/journal/journald-kmsg.c
+++ b/src/journal/journald-kmsg.c
@@ -436,6 +436,7 @@ fail:
 int server_open_kernel_seqnum(Server *s) {
         _cleanup_close_ int fd;
         uint64_t *p;
+        int r = 0;
 
         assert(s);
 
@@ -449,7 +450,19 @@ int server_open_kernel_seqnum(Server *s) {
                 return 0;
         }
 
-        if (posix_fallocate(fd, 0, sizeof(uint64_t)) < 0) {
+#ifdef HAVE_POSIX_FALLOCATE
+        r = posix_fallocate(fd, 0, sizeof(uint64_t));
+#else
+        /* Use good old method to write zeros into the journal file
+           perhaps very inefficient yet working. */
+        char *buf = alloca(sizeof(uint64_t));
+        off_t oldpos = lseek(fd, 0, SEEK_CUR);
+        bzero(buf, sizeof(uint64_t));
+        lseek(fd, 0, SEEK_SET);
+        r = write(fd, buf, sizeof(uint64_t));
+        lseek(fd, oldpos, SEEK_SET);
+#endif /* HAVE_POSIX_FALLOCATE */
+        if (r < 0) {
                 log_error_errno(errno, "Failed to allocate sequential number file, ignoring: %m");
                 return 0;
         }
-- 
2.1.4