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Diffstat (limited to 'Documentation/filesystems/nfs/fault_injection.txt')
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diff --git a/Documentation/filesystems/nfs/fault_injection.txt b/Documentation/filesystems/nfs/fault_injection.txt deleted file mode 100644 index f3a5b0a8ac05..000000000000 --- a/Documentation/filesystems/nfs/fault_injection.txt +++ /dev/null @@ -1,69 +0,0 @@ - -Fault Injection -=============== -Fault injection is a method for forcing errors that may not normally occur, or -may be difficult to reproduce. Forcing these errors in a controlled environment -can help the developer find and fix bugs before their code is shipped in a -production system. Injecting an error on the Linux NFS server will allow us to -observe how the client reacts and if it manages to recover its state correctly. - -NFSD_FAULT_INJECTION must be selected when configuring the kernel to use this -feature. - - -Using Fault Injection -===================== -On the client, mount the fault injection server through NFS v4.0+ and do some -work over NFS (open files, take locks, ...). - -On the server, mount the debugfs filesystem to <debug_dir> and ls -<debug_dir>/nfsd. This will show a list of files that will be used for -injecting faults on the NFS server. As root, write a number n to the file -corresponding to the action you want the server to take. The server will then -process the first n items it finds. So if you want to forget 5 locks, echo '5' -to <debug_dir>/nfsd/forget_locks. A value of 0 will tell the server to forget -all corresponding items. A log message will be created containing the number -of items forgotten (check dmesg). - -Go back to work on the client and check if the client recovered from the error -correctly. - - -Available Faults -================ -forget_clients: - The NFS server keeps a list of clients that have placed a mount call. If - this list is cleared, the server will have no knowledge of who the client - is, forcing the client to reauthenticate with the server. - -forget_openowners: - The NFS server keeps a list of what files are currently opened and who - they were opened by. Clearing this list will force the client to reopen - its files. - -forget_locks: - The NFS server keeps a list of what files are currently locked in the VFS. - Clearing this list will force the client to reclaim its locks (files are - unlocked through the VFS as they are cleared from this list). - -forget_delegations: - A delegation is used to assure the client that a file, or part of a file, - has not changed since the delegation was awarded. Clearing this list will - force the client to reacquire its delegation before accessing the file - again. - -recall_delegations: - Delegations can be recalled by the server when another client attempts to - access a file. This test will notify the client that its delegation has - been revoked, forcing the client to reacquire the delegation before using - the file again. - - -tools/nfs/inject_faults.sh script -================================= -This script has been created to ease the fault injection process. This script -will detect the mounted debugfs directory and write to the files located there -based on the arguments passed by the user. For example, running -`inject_faults.sh forget_locks 1` as root will instruct the server to forget -one lock. Running `inject_faults forget_locks` will instruct the server to -forgetall locks. |