Merge tag 'v5.7-rc7' into perf/core, to pick up fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 18 insertions, 0 deletions

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index b0d42ece4d7c..981f11ec51bc 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -58,6 +58,24 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr)
 		if (attr->ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID))
 			attr->ia_valid &= ~ATTR_MODE;
 
+		/*
+		 * We might have to translate ovl file into real file object
+		 * once use cases emerge.  For now, simply don't let underlying
+		 * filesystem rely on attr->ia_file
+		 */
+		attr->ia_valid &= ~ATTR_FILE;
+
+		/*
+		 * If open(O_TRUNC) is done, VFS calls ->setattr with ATTR_OPEN
+		 * set.  Overlayfs does not pass O_TRUNC flag to underlying
+		 * filesystem during open -> do not pass ATTR_OPEN.  This
+		 * disables optimization in fuse which assumes open(O_TRUNC)
+		 * already set file size to 0.  But we never passed O_TRUNC to
+		 * fuse.  So by clearing ATTR_OPEN, fuse will be forced to send
+		 * setattr request to server.
+		 */
+		attr->ia_valid &= ~ATTR_OPEN;
+
 		inode_lock(upperdentry->d_inode);
 		old_cred = ovl_override_creds(dentry->d_sb);
 		err = notify_change(upperdentry, attr, NULL);