[PATCH] virtiofsd/passthrough_ll: don't remove O_DIRECT when cache=none

[Catherine Ho <catherine.hecx@gmail.com>]

cache=none means to bypass host cache. So we can't remove O_DIRECT flag in
unconditionally in update_open_flags();

Signed-off-by: Catherine Ho <catherine.hecx@gmail.com>
---
 tools/virtiofsd/passthrough_ll.c |   16 ++++++++++------
 1 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
index 4c35c95..889e144 100644
--- a/tools/virtiofsd/passthrough_ll.c
+++ b/tools/virtiofsd/passthrough_ll.c
@@ -1677,7 +1677,8 @@ static void lo_releasedir(fuse_req_t req, fuse_ino_t ino,
     fuse_reply_err(req, 0);
 }
 
-static void update_open_flags(int writeback, struct fuse_file_info *fi)
+static void update_open_flags(int writeback, int cache_mode,
+                              struct fuse_file_info *fi)
 {
     /*
      * With writeback cache, kernel may send read requests even
@@ -1702,10 +1703,13 @@ static void update_open_flags(int writeback, struct fuse_file_info *fi)
 
     /*
      * O_DIRECT in guest should not necessarily mean bypassing page
-     * cache on host as well. If somebody needs that behavior, it
-     * probably should be a configuration knob in daemon.
+     * cache on host as well. If cache=none, set the flag to O_DIRECT
      */
-    fi->flags &= ~O_DIRECT;
+    if (cache_mode == CACHE_NONE) {
+        fi->flags |= O_DIRECT;
+    } else {
+        fi->flags &= ~O_DIRECT;
+    }
 }
 
 static void lo_create(fuse_req_t req, fuse_ino_t parent, const char *name,
@@ -1737,7 +1741,7 @@ static void lo_create(fuse_req_t req, fuse_ino_t parent, const char *name,
         goto out;
     }
 
-    update_open_flags(lo->writeback, fi);
+    update_open_flags(lo->writeback, lo->cache, fi);
 
     fd = openat(parent_inode->fd, name, (fi->flags | O_CREAT) & ~O_NOFOLLOW,
                 mode);
@@ -1947,7 +1951,7 @@ static void lo_open(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi)
     fuse_log(FUSE_LOG_DEBUG, "lo_open(ino=%" PRIu64 ", flags=%d)\n", ino,
              fi->flags);
 
-    update_open_flags(lo->writeback, fi);
+    update_open_flags(lo->writeback, lo->cache, fi);
 
     sprintf(buf, "%i", lo_fd(req, ino));
     fd = openat(lo->proc_self_fd, buf, fi->flags & ~O_NOFOLLOW);
-- 
1.7.1