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It is possible for two distinct clients to have the same cl_ipaddr: - if the client admin disables callback with clientaddr=0.0.0.0 on more than one client - if two clients behind separate NATs use the same private subnet number - if the client admin specifies the same address via clientaddr= mount option (pointing the server at the same NAT box, for example) Because of the way the Linux NFSv4.0 client constructs its client ID string by default, such clients could interfere with each others' lease state when mounting the same server: scnprintf(str, len, "Linux NFSv4.0 %s/%s %s", clp->cl_ipaddr, rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_ADDR), rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_PROTO)); cl_ipaddr is set to the value of the clientaddr= mount option. Two clients whose addresses are 192.168.3.77 that mount the same server (whose public IP address is, say, 3.4.5.6) would both generate the same client ID string when sending a SETCLIENTID: Linux NFSv4.0 192.168.3.77/3.4.5.6 tcp and thus the server would not be able to distinguish the clients' leases. If both clients are using AUTH_SYS when sending SETCLIENTID then the server could possibly permit the two clients to interfere with or purge each others' leases. To better ensure that Linux's NFSv4.0 client ID strings are distinct in these cases, remove cl_ipaddr from the client ID string and replace it with something more likely to be unique. Note that the replacement looks a lot like the uniform client ID string. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.