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: Eric Blake <[email protected]> Signed-off-by: Daniel P. Berrangé <[email protected]> --- util/osdep.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/util/osdep.c b/util/osdep.c index a4956fbf6b..6c24985f7a 100644 --- a/util/osdep.c +++ b/util/osdep.c @@ -345,6 +345,19 @@ 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 + 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' flags 0x%x: " + "filesystem does not support O_DIRECT", + action, name, flags); + errno = EINVAL; /* close() clobbered earlier errno */ + return -1; + } + } +#endif /* O_DIRECT */ error_setg_errno(errp, errno, "Could not %s '%s' flags 0x%x", action, name, flags); } -- 2.26.2
