CIFS: Fix SMB2 oplock break processing (fa9c2362) · Commits · 戴 / test

Even when mounting modern protocol version the server may be configured without supporting SMB2.1 leases and the client uses SMB2 oplock to optimize IO performance through local caching. However there is a problem in oplock break handling that leads to missing a break notification on the client who has a file opened. It latter causes big latencies to other clients that are trying to open the same file. The problem reproduces when there are multiple shares from the same server mounted on the client. The processing code tries to match persistent and volatile file ids from the break notification with an open file but it skips all share besides the first one. Fix this by looking up in all shares belonging to the server that issued the oplock break. Cc: Stable <stable@vger.kernel.org> Signed-off-by:

Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by:

Steve French <stfrench@microsoft.com>

fs/cifs/smb2misc.c

+3 −4

Original line number	Diff line number	Diff line
		@@ -667,10 +667,10 @@ smb2_is_valid_oplock_break(char buffer, struct TCP_Server_Info server)
		spin_lock(&cifs_tcp_ses_lock);
		list_for_each(tmp, &server->smb_ses_list) {
		ses = list_entry(tmp, struct cifs_ses, smb_ses_list);

		list_for_each(tmp1, &ses->tcon_list) {
		tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);

		cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
		spin_lock(&tcon->open_file_lock);
		list_for_each(tmp2, &tcon->openFileList) {
		cfile = list_entry(tmp2, struct cifsFileInfo,
		@@ -682,6 +682,8 @@ smb2_is_valid_oplock_break(char buffer, struct TCP_Server_Info server)
		continue;

		cifs_dbg(FYI, "file id match, oplock break\n");
		cifs_stats_inc(
		&tcon->stats.cifs_stats.num_oplock_brks);
		cinode = CIFS_I(d_inode(cfile->dentry));
		spin_lock(&cfile->file_info_lock);
		if (!CIFS_CACHE_WRITE(cinode) &&
		@@ -714,9 +716,6 @@ smb2_is_valid_oplock_break(char buffer, struct TCP_Server_Info server)
		return true;
		}
		spin_unlock(&tcon->open_file_lock);
		spin_unlock(&cifs_tcp_ses_lock);
		cifs_dbg(FYI, "No matching file for oplock break\n");
		return true;
		}
		}
		spin_unlock(&cifs_tcp_ses_lock);

Admin message