From 661b3e81a336570dfbf4c224595921d490ac792f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= Date: Tue, 21 Jul 2020 16:17:35 +0100 Subject: [PATCH] util: give a specific error message when O_DIRECT doesn't work MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A common error scenario is to tell QEMU to use O_DIRECT in combination with a filesystem that doesn't support it. To aid users to diagnosing their mistake we want to provide a clear error message when this happens. Reviewed-by: Markus Armbruster Reviewed-by: Eric Blake Signed-off-by: Daniel P. Berrangé --- util/osdep.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/util/osdep.c b/util/osdep.c index c99f1e7db2..8ea7a807c1 100644 --- a/util/osdep.c +++ b/util/osdep.c @@ -332,11 +332,24 @@ qemu_open_internal(const char *name, int flags, mode_t mode, Error **errp) if (ret == -1) { const char *action = flags & O_CREAT ? "create" : "open"; +#ifdef O_DIRECT + /* Give more helpful error message for O_DIRECT */ + if (errno == EINVAL && (flags & O_DIRECT)) { + ret = open(name, flags & ~O_DIRECT, mode); + if (ret != -1) { + close(ret); + error_setg(errp, "Could not %s '%s': " + "filesystem does not support O_DIRECT", + action, name); + errno = EINVAL; /* restore first open()'s errno */ + return -1; + } + } +#endif /* O_DIRECT */ error_setg_errno(errp, errno, "Could not %s '%s'", action, name); } - return ret; }