[Qemu-devel] [PATCH v8 2/2] linux-user: Add support for syncfs() syscall

[Aleksandar Markovic]

From: Aleksandar Markovic <address@hidden>

This patch implements Qemu user mode syncfs() syscall support. Syscall
syncfs() syncs the filesystem containing file determined by the open
file descriptor passed as the argument to syncfs().

The implementation consists of a straightforward invocation of host's
syncfs(). Configure and strace support is included as well.

Signed-off-by: Aleksandar Markovic <address@hidden>
---
 configure              | 18 ++++++++++++++++++
 linux-user/strace.list |  2 +-
 linux-user/syscall.c   |  5 +++++
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/configure b/configure
index 044e0cd..7b9984b 100755
--- a/configure
+++ b/configure
@@ -3913,6 +3913,21 @@ if compile_prog "" "" ; then
   clock_adjtime=yes
 fi
 
+# syncfs probe
+syncfs=no
+cat > $TMPC <<EOF
+#include <unistd.h>
+
+int main(void)
+{
+    return syncfs(0);
+}
+EOF
+syncfs=no
+if compile_prog "" "" ; then
+  syncfs=yes
+fi
+
 # Check if tools are available to build documentation.
 if test "$docs" != "no" ; then
   if has makeinfo && has pod2man; then
@@ -5201,6 +5216,9 @@ fi
 if test "$clock_adjtime" = "yes" ; then
   echo "CONFIG_CLOCK_ADJTIME=y" >> $config_host_mak
 fi
+if test "$syncfs" = "yes" ; then
+  echo "CONFIG_SYNCFS=y" >> $config_host_mak
+fi
 if test "$inotify" = "yes" ; then
   echo "CONFIG_INOTIFY=y" >> $config_host_mak
 fi
diff --git a/linux-user/strace.list b/linux-user/strace.list
index 9355075..c549f99 100644
--- a/linux-user/strace.list
+++ b/linux-user/strace.list
@@ -1462,7 +1462,7 @@
 { TARGET_NR_sync_file_range, "sync_file_range" , NULL, NULL, NULL },
 #endif
 #ifdef TARGET_NR_syncfs
-{ TARGET_NR_syncfs, "syncfs" , NULL, NULL, NULL },
+{ TARGET_NR_syncfs, "syncfs" , "%s(%d)", NULL, NULL },
 #endif
 #ifdef TARGET_NR_syscall
 { TARGET_NR_syscall, "syscall" , NULL, NULL, NULL },
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 25be16b..850f4cc 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -8071,6 +8071,11 @@ abi_long do_syscall(void *cpu_env, int num, abi_long 
arg1,
         sync();
         ret = 0;
         break;
+#if defined(TARGET_NR_syncfs) && defined(CONFIG_SYNCFS)
+    case TARGET_NR_syncfs:
+        ret = get_errno(syncfs(arg1));
+        break;
+#endif
     case TARGET_NR_kill:
         ret = get_errno(safe_kill(arg1, target_to_host_signal(arg2)));
         break;
-- 
2.9.3