ovl: get_write_access() in truncate

[cascardo/linux.git] / fs / overlayfs / inode.c

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 8514d69..c831c2e 100644 (file)
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -59,16 +59,37 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr)
        if (err)
                goto out;
 
+       if (attr->ia_valid & ATTR_SIZE) {
+               struct inode *realinode = d_inode(ovl_dentry_real(dentry));
+
+               err = -ETXTBSY;
+               if (atomic_read(&realinode->i_writecount) < 0)
+                       goto out_drop_write;
+       }
+
        err = ovl_copy_up(dentry);
        if (!err) {
+               struct inode *winode = NULL;
+
                upperdentry = ovl_dentry_upper(dentry);
 
+               if (attr->ia_valid & ATTR_SIZE) {
+                       winode = d_inode(upperdentry);
+                       err = get_write_access(winode);
+                       if (err)
+                               goto out_drop_write;
+               }
+
                inode_lock(upperdentry->d_inode);
                err = notify_change(upperdentry, attr, NULL);
                if (!err)
                        ovl_copyattr(upperdentry->d_inode, dentry->d_inode);
                inode_unlock(upperdentry->d_inode);
+
+               if (winode)
+                       put_write_access(winode);
        }
+out_drop_write:
        ovl_drop_write(dentry);
 out:
        return err;