fuse: enable proper "fgetattr"-like semantics

GETATTR FUSE message can carry a file handle
reference in which case it serves as a hint
for the FUSE server that the stat data is
preferably acquired in context of the given
filehandle (which we call '"fgetattr"-like
semantics').

So far FUSE ignored the GETTATTR provided
filehandle and grabbed a file handle
heuristically. This caused confusion in the
caching layers, which has been tracked down
as one of the reasons of referred BUG.

As of the BUG, this is just a partial fix.

BUG: 1512691
Change-Id: I67eebbf5407ca725ed111fbda4181ead10d03f6d
Signed-off-by: Csaba Henk <csaba@redhat.com>

1 files changed, 13 insertions, 1 deletions

diff --git a/xlators/mount/fuse/src/fuse-bridge.c b/xlators/mount/fuse/src/fuse-bridge.c
index 076fbfddaf8..dee9b16abf3 100644
--- a/xlators/mount/fuse/src/fuse-bridge.c
+++ b/xlators/mount/fuse/src/fuse-bridge.c
@@ -930,7 +930,10 @@ fuse_getattr_resume (fuse_state_t *state)
         }
 
         if (!IA_ISDIR (state->loc.inode->ia_type)) {
-                state->fd = fd_lookup (state->loc.inode, 0);
+                if (state->fd == NULL)
+                        state->fd = fd_lookup (state->loc.inode, state->finh->pid);
+                if (state->fd == NULL)
+                        state->fd = fd_lookup (state->loc.inode, 0);
         }
 
         if (!state->fd) {
@@ -956,9 +959,18 @@ fuse_getattr_resume (fuse_state_t *state)
 static void
 fuse_getattr (xlator_t *this, fuse_in_header_t *finh, void *msg)
 {
+#if FUSE_KERNEL_MINOR_VERSION >= 9
+        struct fuse_getattr_in *fgi  = msg;
+        fuse_private_t         *priv = NULL;
+#endif
         fuse_state_t *state;
 
         GET_STATE (this, finh, state);
+#if FUSE_KERNEL_MINOR_VERSION >= 9
+        priv = this->private;
+        if (priv->proto_minor >= 9 && fgi->getattr_flags & FUSE_GETATTR_FH)
+                state->fd = fd_ref ((fd_t *)fgi->fh);
+#endif
 
         fuse_resolve_inode_init (state, &state->resolve, state->finh->nodeid);