fuse: fix truncate after open

Commit e1181ee6 "vfs: pass struct file to do_truncate on O_TRUNC
opens" broke the behavior of open(O_TRUNC|O_RDONLY) in fuse.  Fuse
assumed that when called from open, a truncate() will be done, not an
ftruncate().

Fix by restoring the old behavior, based on the ATTR_OPEN flag.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

1 files changed, 5 insertions, 2 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index bfed8447ed80..83543b5ff941 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1283,8 +1283,11 @@ static int fuse_do_setattr(struct dentry *entry, struct iattr *attr,
         if (err)
                 return err;
 
-        if ((attr->ia_valid & ATTR_OPEN) && fc->atomic_o_trunc)
-                return 0;
+        if (attr->ia_valid & ATTR_OPEN) {
+                if (fc->atomic_o_trunc)
+                        return 0;
+                file = NULL;
+        }
 
         if (attr->ia_valid & ATTR_SIZE)
                 is_truncate = true;