[Virtio-fs] [virtiofsd PATCH v6 3/6] virtiofsd: negotiate per-file DAX in FUSE_INIT

[Jeffle Xu]

Among the FUSE_INIT phase, guest virtiofs will advertise per-file DAX
if it's mounted with "-o dax=inode". Then virtiofsd is aware that
client is in per-file DAX mode, and will construct per-inode DAX
attribute accordingly.

Signed-off-by: Jeffle Xu <jefflexu at linux.alibaba.com>
---
 tools/virtiofsd/fuse_common.h   | 5 +++++
 tools/virtiofsd/fuse_lowlevel.c | 3 +++
 2 files changed, 8 insertions(+)

diff --git a/tools/virtiofsd/fuse_common.h b/tools/virtiofsd/fuse_common.h
index 8a75729be9..ee6fc64c23 100644
--- a/tools/virtiofsd/fuse_common.h
+++ b/tools/virtiofsd/fuse_common.h
@@ -372,6 +372,11 @@ struct fuse_file_info {
  */
 #define FUSE_CAP_HANDLE_KILLPRIV_V2 (1 << 28)
 
+/**
+ * Indicates support for per-file DAX.
+ */
+#define FUSE_CAP_PERFILE_DAX (1 << 29)
+
 /**
  * Ioctl flags
  *
diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c
index bee781982b..dbb0b3d275 100644
--- a/tools/virtiofsd/fuse_lowlevel.c
+++ b/tools/virtiofsd/fuse_lowlevel.c
@@ -2066,6 +2066,9 @@ static void do_init(fuse_req_t req, fuse_ino_t nodeid,
     if (arg->flags & FUSE_HANDLE_KILLPRIV_V2) {
         se->conn.capable |= FUSE_CAP_HANDLE_KILLPRIV_V2;
     }
+    if (arg->flags & FUSE_PERFILE_DAX) {
+        se->conn.capable |= FUSE_CAP_PERFILE_DAX;
+    }
 #ifdef HAVE_SPLICE
 #ifdef HAVE_VMSPLICE
     se->conn.capable |= FUSE_CAP_SPLICE_WRITE | FUSE_CAP_SPLICE_MOVE;
-- 
2.27.0