smb3: improve handling of share deleted (and share recreated)

When a share is deleted, returning EIO is confusing and no useful
information is logged. Improve the handling of this case by
at least logging a better error for this (and also mapping the error
differently to EREMCHG). See e.g. the new messages that would be logged:

[55243.639530] server share \\192.168.1.219\scratch deleted
[55243.642568] CIFS VFS: \\192.168.1.219\scratch BAD_NETWORK_NAME: \\192.168.1.219\scratch

In addition for the case where a share is deleted and then recreated
with the same name, have now fixed that so it works. This is sometimes
done for example, because the admin had to move a share to a different,
bigger local drive when a share is running low on space.

Signed-off-by: Steve French <[e-mail]>
Reviewed-by: Ronnie Sahlberg <[e-mail]>

fs/cifs/smb2inode.c

···
 		cifsFileInfo_put(cfile);
 
 	SMB2_open_free(&rqst[0]);
+	if (rc == -EREMCHG) {
+		printk_once(KERN_WARNING "server share %s deleted\n",
+			    tcon->treeName);
+		tcon->need_reconnect = true;
+	}
+
 	switch (command) {
 	case SMB2_OP_QUERY_INFO:
 		if (rc == 0) {

fs/cifs/smb2maperror.c

···
 	{STATUS_PRINT_QUEUE_FULL, -EIO, "STATUS_PRINT_QUEUE_FULL"},
 	{STATUS_NO_SPOOL_SPACE, -EIO, "STATUS_NO_SPOOL_SPACE"},
 	{STATUS_PRINT_CANCELLED, -EIO, "STATUS_PRINT_CANCELLED"},
-	{STATUS_NETWORK_NAME_DELETED, -EIO, "STATUS_NETWORK_NAME_DELETED"},
+	{STATUS_NETWORK_NAME_DELETED, -EREMCHG, "STATUS_NETWORK_NAME_DELETED"},
 	{STATUS_NETWORK_ACCESS_DENIED, -EACCES, "STATUS_NETWORK_ACCESS_DENIED"},
 	{STATUS_BAD_DEVICE_TYPE, -EIO, "STATUS_BAD_DEVICE_TYPE"},
 	{STATUS_BAD_NETWORK_NAME, -ENOENT, "STATUS_BAD_NETWORK_NAME"},

fs/cifs/smb2ops.c

···
 
 	/* Cached root is still invalid, continue normaly */
 
-	if (rc)
+	if (rc) {
+		if (rc == -EREMCHG) {
+			tcon->need_reconnect = true;
+			printk_once(KERN_WARNING "server share %s deleted\n",
+				    tcon->treeName);
+		}
 		goto oshr_exit;
+	}
 
 	o_rsp = (struct smb2_create_rsp *)rsp_iov[0].iov_base;
 	oparms.fid->persistent_fid = o_rsp->PersistentFileId;
···
 				resp_buftype, rsp_iov);
 	if (rc) {
 		free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base);
+		if (rc == -EREMCHG) {
+			tcon->need_reconnect = true;
+			printk_once(KERN_WARNING "server share %s deleted\n",
+				    tcon->treeName);
+		}
 		goto qic_exit;
 	}
 	*rsp = rsp_iov[1];

fs/cifs/smb2pdu.c

···
 		}
 		trace_smb3_open_err(xid, tcon->tid, ses->Suid,
 				    oparms->create_options, oparms->desired_access, rc);
+		if (rc == -EREMCHG) {
+			printk_once(KERN_WARNING "server share %s deleted\n",
+				    tcon->treeName);
+			tcon->need_reconnect = true;
+		}
 		goto creat_exit;
 	} else
 		trace_smb3_open_done(xid, rsp->PersistentFileId, tcon->tid,