diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-01-14 12:26:41 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-01-14 12:26:41 -0800 |
commit | 0b48d42235caf627121f440b57d376f48a9af8b6 (patch) | |
tree | 400967c5fcb1cd08bbc0e1739e229f9717590f19 /Documentation/filesystems | |
parent | 8e63dd6e1c589ba99a18df9cbaa41c3178607641 (diff) | |
parent | 7a6ef8c72314f254c107c6a9ed7cb201961ee05a (diff) | |
download | linux-0b48d42235caf627121f440b57d376f48a9af8b6.tar.bz2 |
Merge branch 'for-3.3' of git://linux-nfs.org/~bfields/linux
* 'for-3.3' of git://linux-nfs.org/~bfields/linux: (31 commits)
nfsd4: nfsd4_create_clid_dir return value is unused
NFSD: Change name of extended attribute containing junction
svcrpc: don't revert to SVC_POOL_DEFAULT on nfsd shutdown
svcrpc: fix double-free on shutdown of nfsd after changing pool mode
nfsd4: be forgiving in the absence of the recovery directory
nfsd4: fix spurious 4.1 post-reboot failures
NFSD: forget_delegations should use list_for_each_entry_safe
NFSD: Only reinitilize the recall_lru list under the recall lock
nfsd4: initialize special stateid's at compile time
NFSd: use network-namespace-aware cache registering routines
SUNRPC: create svc_xprt in proper network namespace
svcrpc: update outdated BKL comment
nfsd41: allow non-reclaim open-by-fh's in 4.1
svcrpc: avoid memory-corruption on pool shutdown
svcrpc: destroy server sockets all at once
svcrpc: make svc_delete_xprt static
nfsd: Fix oops when parsing a 0 length export
nfsd4: Use kmemdup rather than duplicating its implementation
nfsd4: add a separate (lockowner, inode) lookup
nfsd4: fix CONFIG_NFSD_FAULT_INJECTION compile error
...
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r-- | Documentation/filesystems/nfs/00-INDEX | 2 | ||||
-rw-r--r-- | Documentation/filesystems/nfs/fault_injection.txt | 69 |
2 files changed, 71 insertions, 0 deletions
diff --git a/Documentation/filesystems/nfs/00-INDEX b/Documentation/filesystems/nfs/00-INDEX index a57e12411d2a..1716874a651e 100644 --- a/Documentation/filesystems/nfs/00-INDEX +++ b/Documentation/filesystems/nfs/00-INDEX @@ -2,6 +2,8 @@ - this file (nfs-related documentation). Exporting - explanation of how to make filesystems exportable. +fault_injection.txt + - information for using fault injection on the server knfsd-stats.txt - statistics which the NFS server makes available to user space. nfs.txt diff --git a/Documentation/filesystems/nfs/fault_injection.txt b/Documentation/filesystems/nfs/fault_injection.txt new file mode 100644 index 000000000000..426d166089a3 --- /dev/null +++ b/Documentation/filesystems/nfs/fault_injection.txt @@ -0,0 +1,69 @@ + +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 reaquire 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 reaquire 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. |