From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Thu, 22 Aug 2013 09:29:03 +0000 (+0200)
Subject: osdep: warn if open(O_DIRECT) on fails with EINVAL
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a5813077aac7865f69b7ee46a594f3705429f7cd;p=qemu.git

osdep: warn if open(O_DIRECT) on fails with EINVAL

Print a warning when opening a file O_DIRECT fails with EINVAL.  This
saves users a lot of time trying to figure out the EINVAL error, which
is typical when attempting to open a file O_DIRECT on Linux tmpfs.

Reported-by: Deepak C Shetty <deepakcs@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---

diff --git a/util/osdep.c b/util/osdep.c
index 685c8ae889..62072b4be3 100644
--- a/util/osdep.c
+++ b/util/osdep.c
@@ -207,6 +207,13 @@ int qemu_open(const char *name, int flags, ...)
     }
 #endif
 
+#ifdef O_DIRECT
+    if (ret == -1 && errno == EINVAL && (flags & O_DIRECT)) {
+        error_report("file system may not support O_DIRECT");
+        errno = EINVAL; /* in case it was clobbered */
+    }
+#endif /* O_DIRECT */
+
     return ret;
 }