ovl: introduce copy up waitqueue
The overlay sb 'copyup_wq' and overlay inode 'copying' condition
variable are about to replace the upper sb rename_lock, as finer
grained synchronization objects for concurrent copy up.
Suggested-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 952286f..01157d6 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -263,3 +263,33 @@
{
return dentry_open(path, flags | O_NOATIME, current_cred());
}
+
+int ovl_copy_up_start(struct dentry *dentry)
+{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ struct ovl_entry *oe = dentry->d_fsdata;
+ int err;
+
+ spin_lock(&ofs->copyup_wq.lock);
+ err = wait_event_interruptible_locked(ofs->copyup_wq, !oe->copying);
+ if (!err) {
+ if (oe->__upperdentry)
+ err = 1; /* Already copied up */
+ else
+ oe->copying = true;
+ }
+ spin_unlock(&ofs->copyup_wq.lock);
+
+ return err;
+}
+
+void ovl_copy_up_end(struct dentry *dentry)
+{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ spin_lock(&ofs->copyup_wq.lock);
+ oe->copying = false;
+ wake_up_locked(&ofs->copyup_wq);
+ spin_unlock(&ofs->copyup_wq.lock);
+}