Lines Matching +full:lock +full:- +full:state
1 .. SPDX-License-Identifier: GPL-2.0
8 instances in order to maintain file open and lock state during
19 ------------
21 The NFSv4 protocol uses "lease-based file locking". Leases help
22 NFSv4 servers provide file lock guarantees and manage their
26 The server collects each client's file open and lock state under
35 and lock state after a certain period of time. When a client
36 restarts, it indicates to servers that open and lock state
42 their state, the server uses this list to distinguish amongst
43 clients that held state before the server restarted and clients
44 sending fresh OPEN and LOCK requests. This enables file locks to
48 ------------------------
54 - co_ownerid: An arbitrary but fixed string.
56 - boot verifier: A 64-bit incarnation verifier that enables a
72 - The "co_ownerid" string identifies the client during reboot
75 - The "co_ownerid" string helps servers distinguish the client
79 - Because it often appears on the network in the clear, the
82 - The content of the "co_ownerid" string is set and unchanging
84 - The NFSv4 protocol places a 1024-byte limit on the size of the
87 Protecting NFSv4 lease state
88 ----------------------------
100 Neither client can maintain open or lock state in this scenario.
108 state recovery after a server or client reboot is not guaranteed.
111 the client's previous open and lock state. This blocks access to
112 locked files until the server removes the orphaned state.
116 client to reclaim its open and lock state, and may give those locks
117 to other clients in the meantime. This is referred to as "lock
120 Lease stealing and lock stealing increase the potential for denial
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134 - NFS-root (diskless) clients, where the local DHCP server (or
137 - "Containers" within a single Linux host. If each container has
142 - Clients across multiple administrative domains that access a
161 Note that this file is empty on name-space creation. If the
162 container system has access to some sort of per-container identity
166 sha256sum /etc/machine-id | awk '{print $1}' \\
170 -----------------------
178 lease and lock stealing. However, it might be the only choice for
186 control this behavior. Alternately, a single-user client with a
193 flavor with Kerberos and the integrity QOS to prevent in-transit
197 ----------------
202 Once a client establishes open and lock state, the NFSv4 protocol
203 enables lease state to transition to other servers, following data
205 running applications. The Linux NFSv4 client facilitates state
213 - nfs(5)
214 - kerberos(7)
215 - RFC 7530 for the NFSv4.0 specification
216 - RFC 8881 for the NFSv4.1 specification.