diff mbox series

[v2] virtiofsd/passthrough_ll: don't remove O_DIRECT when cache=none

Message ID 1586594144-24605-1-git-send-email-catherine.hecx@gmail.com
State New
Headers show
Series [v2] virtiofsd/passthrough_ll: don't remove O_DIRECT when cache=none | expand

Commit Message

Catherine Ho April 11, 2020, 8:35 a.m. UTC 
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>
---
v2: Fix to keep flags unchanged if cache=none, otherwise changed the file
    without O_DIRECT incorrectly.
 tools/virtiofsd/passthrough_ll.c |   14 ++++++++------
 1 files changed, 8 insertions(+), 6 deletions(-)
diff mbox series

Patch

diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
index 4c35c95..59e64dd 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 +1703,11 @@  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, keep the flag unchanged
      */
-    fi->flags &= ~O_DIRECT;
+    if (cache_mode != CACHE_NONE) {
+        fi->flags &= ~O_DIRECT;
+    }
 }
 
 static void lo_create(fuse_req_t req, fuse_ino_t parent, const char *name,
@@ -1737,7 +1739,7 @@  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 +1949,7 @@  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);