[Qemu-devel] [PATCH 03/12] nbd: support NBD_SET_FLAGS ioctl

[Paolo Bonzini]

The nbd kernel module cannot enable DISCARD requests unless it is
informed about it.  The flags field in the header is used for this,
and this patch adds support for it.

Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
 nbd.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/nbd.c b/nbd.c
index 9ed2239..30cd78f 100644
--- a/nbd.c
+++ b/nbd.c
@@ -377,6 +377,14 @@ int nbd_init(int fd, int csock, uint32_t flags, off_t 
size, size_t blocksize)
         }
     }
 
+    if (ioctl(fd, NBD_SET_FLAGS, flags) < 0
+        && errno != ENOTTY) {
+        int serrno = errno;
+        LOG("Failed setting flags");
+        errno = serrno;
+        return -1;
+    }
+
     TRACE("Clearing NBD socket");
 
     if (ioctl(fd, NBD_CLEAR_SOCK) == -1) {
-- 
1.7.6