[PATCH 12/30] virtiofsd: Make fsync work even if only inode is passed in

[Dr. David Alan Gilbert (git)]

From: Vivek Goyal <address@hidden>

If caller has not sent file handle in request, then using inode, retrieve
the fd opened using O_PATH and use that to open file again and issue
fsync. This will be needed when dax_flush() calls fsync. At that time
we only have inode information (and not file).

Signed-off-by: Vivek Goyal <address@hidden>
---
 contrib/virtiofsd/fuse_lowlevel.c  |  9 ++++++---
 contrib/virtiofsd/passthrough_ll.c | 24 ++++++++++++++++++++++--
 2 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/contrib/virtiofsd/fuse_lowlevel.c 
b/contrib/virtiofsd/fuse_lowlevel.c
index ff68ec0c9d..6fe7506ead 100644
--- a/contrib/virtiofsd/fuse_lowlevel.c
+++ b/contrib/virtiofsd/fuse_lowlevel.c
@@ -1083,9 +1083,12 @@ static void do_fsync(fuse_req_t req, fuse_ino_t nodeid, 
const void *inarg)
        memset(&fi, 0, sizeof(fi));
        fi.fh = arg->fh;
 
-       if (req->se->op.fsync)
-               req->se->op.fsync(req, nodeid, datasync, &fi);
-       else
+       if (req->se->op.fsync) {
+               if (fi.fh == (uint64_t)-1)
+                       req->se->op.fsync(req, nodeid, datasync, NULL);
+               else
+                       req->se->op.fsync(req, nodeid, datasync, &fi);
+       } else
                fuse_reply_err(req, ENOSYS);
 }
 
diff --git a/contrib/virtiofsd/passthrough_ll.c 
b/contrib/virtiofsd/passthrough_ll.c
index 72fae9d10b..63a32c87c3 100644
--- a/contrib/virtiofsd/passthrough_ll.c
+++ b/contrib/virtiofsd/passthrough_ll.c
@@ -863,10 +863,30 @@ static void lo_fsync(fuse_req_t req, fuse_ino_t ino, int 
datasync,
 {
        int res;
        (void) ino;
+       int fd;
+       char *buf;
+
+       fuse_log(FUSE_LOG_DEBUG, "lo_fsync(ino=%" PRIu64 ", fi=0x%p)\n", ino,
+                (void *)fi);
+
+       if (!fi) {
+               res = asprintf(&buf, "/proc/self/fd/%i", lo_fd(req, ino));
+               if (res == -1)
+                       return (void) fuse_reply_err(req, errno);
+
+               fd = open(buf, O_RDWR);
+               free(buf);
+               if (fd == -1)
+                       return (void) fuse_reply_err(req, errno);
+       } else
+               fd = fi->fh;
+
        if (datasync)
-               res = fdatasync(fi->fh);
+               res = fdatasync(fd);
        else
-               res = fsync(fi->fh);
+               res = fsync(fd);
+       if (!fi)
+               close(fd);
        fuse_reply_err(req, res == -1 ? errno : 0);
 }
 
-- 
2.23.0