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path: root/fs/dlm/lock.c
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2009-01-08dlm: change rsbtbl rwlock to spinlockDavid Teigland
The rwlock is almost always used in write mode, so there's no reason to not use a spinlock instead. Signed-off-by: David Teigland <teigland@redhat.com>
2008-12-23dlm: add time stamp of blocking callbackDavid Teigland
Record the time the latest blocking callback was queued for a lock. This will be used for debugging in combination with lock queue timestamp changes in the previous patch. Signed-off-by: David Teigland <teigland@redhat.com>
2008-12-23dlm: change lock time stampingDavid Teigland
Use ktime instead of jiffies for timestamping lkb's. Also stamp the time on every lkb whenever it's added to a resource queue, instead of just stamping locks subject to timeouts. This will allow us to use timestamps more widely for debugging all locks. Signed-off-by: David Teigland <teigland@redhat.com>
2008-12-23dlm: improve how bast mode handlingDavid Teigland
The lkb bastmode value is set in the context of processing the lock, and read by the dlm_astd thread. Because it's accessed in these two separate contexts, the writing/reading ought to be done under a lock. This is simple to do by setting it and reading it when the lkb is added to and removed from dlm_astd's callback list which is properly locked. Signed-off-by: David Teigland <teigland@redhat.com>
2008-07-14dlm: fix uninitialized variable for search_rsb_list callersBenny Halevy
gcc 4.3.0 correctly emits the following warning. search_rsb_list does not *r_ret if no dlm_rsb is found and _search_rsb may pass the uninitialized value upstream on the error path when both calls to search_rsb_list return non-zero error. The fix sets *r_ret to NULL on search_rsb_list's not-found path. Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: David Teigland <teigland@redhat.com>
2008-07-14dlm: fix basts for granted CW waiting PR/CWDavid Teigland
The fix in commit 3650925893469ccb03dbcc6a440c5d363350f591 was addressing the case of a granted PR lock with waiting PR and CW locks. It's a special case that requires forcing a CW bast. However, that forced CW bast was incorrectly applying to a second condition where the granted lock was CW. So, the holder of a CW lock could receive an extraneous CW bast instead of a PR bast. This fix narrows the original special case to what was intended. Signed-off-by: David Teigland <teigland@redhat.com>
2008-04-21dlm: save master info after failed no-queue requestDavid Teigland
When a NOQUEUE request fails, the rsb res_master field is unnecessarily reset to -1, instead of leaving the valid master setting in place. We want to save the looked-up master values while the rsb is on the "toss list" so that another lookup can be avoided if the rsb is soon reused. The fix is to simply leave res_master value alone. Signed-off-by: David Teigland <teigland@redhat.com>
2008-04-21dlm: make dlm_print_rsb() staticAdrian Bunk
dlm_print_rsb() can now become static. Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: David Teigland <teigland@redhat.com>
2008-02-06dlm: eliminate astparam type castingDavid Teigland
Put lkb_astparam in a union with a dlm_user_args pointer to eliminate a lot of type casting. Signed-off-by: David Teigland <teigland@redhat.com>
2008-02-06dlm: proper types for asts and bastsDavid Teigland
Use proper types for ast and bast functions, and use consistent type for ast param. Signed-off-by: David Teigland <teigland@redhat.com>
2008-02-04dlm: fix overflows when copying from ->m_extra to lvbAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Teigland <teigland@redhat.com>
2008-02-04dlm: make find_rsb() fail gracefully when namelen is too largeAl Viro
We *can* get there from receive_request() and dlm_recover_master_copy() with namelen too large if incoming request is invalid; BUG() from DLM_ASSERT() in allocate_rsb() is a bit excessive reaction to that and in case of dlm_recover_master_copy() we would actually oops before that while calculating hash of up to 64Kb worth of data - with data actually being 64 _bytes_ in kmalloc()'ed struct. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Teigland <teigland@redhat.com>
2008-02-04dlm: receive_rcom_lock_args() overflow checkAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Teigland <teigland@redhat.com>
2008-02-04dlm: verify that places expecting rcom_lock have packet long enoughAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Teigland <teigland@redhat.com>
2008-02-04dlm: do not byteswap rcom_lockAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Teigland <teigland@redhat.com>
2008-02-04dlm: dlm_process_incoming_buffer() fixesAl Viro
* check that length is large enough to cover the non-variable part of message or rcom resp. (after checking that it's large enough to cover the header, of course). * kill more pointless casts Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Teigland <teigland@redhat.com>
2008-02-04dlm: use proper C for dlm/requestqueue stuff (and fix alignment bug)Al Viro
a) don't cast the pointer to dlm_header *, we use it as dlm_message * anyway. b) we copy the message into a queue element, then pass the pointer to copy to dlm_receive_message_saved(); declare it properly to make sure that we have the right alignment. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Teigland <teigland@redhat.com>
2008-01-30dlm: keep cached master rsbs during recoveryDavid Teigland
To prevent the master of an rsb from changing rapidly, an unused rsb is kept on the "toss list" for a period of time to be reused. The toss list was being cleared completely for each recovery, which is unnecessary. Much of the benefit of the toss list can be maintained if nodes keep rsb's in their toss list that they are the master of. These rsb's need to be included when the resource directory is rebuilt during recovery. Signed-off-by: David Teigland <teigland@redhat.com>
2008-01-30dlm: change error message to debugDavid Teigland
The invalid lockspace messages are normal and can appear relatively often. They should be suppressed without debugging enabled. Signed-off-by: David Teigland <teigland@redhat.com>
2008-01-30dlm: limit dir lookup loopDavid Teigland
In a rare case we may need to repeat a local resource directory lookup due to a race with removing the rsb and removing the resdir record. We'll never need to do more than a single additional lookup, though, so the infinite loop around the lookup can be removed. In addition to being unnecessary, the infinite loop is dangerous since some other unknown condition may appear causing the loop to never break. Signed-off-by: David Teigland <teigland@redhat.com>
2008-01-30dlm: reject normal unlock when lock is waiting for lookupDavid Teigland
Non-forced unlocks should be rejected if the lock is waiting on the rsb_lookup list for another lock to establish the master node. Signed-off-by: David Teigland <teigland@redhat.com>
2008-01-30dlm: validate messages before processingDavid Teigland
There was some hit and miss validation of messages that has now been cleaned up and unified. Before processing a message, the new validate_message() function checks that the lkb is the appropriate type, process-copy or master-copy, and that the message is from the correct nodeid for the the given lkb. Other checks and assertions on the lkb type and nodeid have been removed. The assertions were particularly bad since they would panic the machine instead of just ignoring the bad message. Although other recent patches have made processing old message unlikely, it still may be possible for an old message to be processed and caught by these checks. Signed-off-by: David Teigland <teigland@redhat.com>
2008-01-30dlm: reject messages from non-membersDavid Teigland
Messages from nodes that are no longer members of the lockspace should be ignored. When nodes are removed from the lockspace, recovery can sometimes complete quickly enough that messages arrive from a removed node after recovery has completed. When processed, these messages would often cause an error message, and could in some cases change some state, causing problems. Signed-off-by: David Teigland <teigland@redhat.com>
2008-01-30dlm: another call to confirm_master in receive_request_replyDavid Teigland
When a failed request (EBADR or ENOTBLK) is unlocked/canceled instead of retried, there may be other lkb's waiting on the rsb_lookup list for it to complete. A call to confirm_master() is needed to move on to the next waiting lkb since the current one won't be retried. Signed-off-by: David Teigland <teigland@redhat.com>
2008-01-30dlm: recover locks waiting for overlap repliesDavid Teigland
When recovery looks at locks waiting for replies, it fails to consider locks that have already received a reply for their first remote operation, but not received a reply for secondary, overlapping unlock/cancel. The appropriate stub reply needs to be called for these waiters. Appears when we start doing recovery in the presence of a many overlapping unlock/cancel ops. Signed-off-by: David Teigland <teigland@redhat.com>
2008-01-30dlm: clear ast_type when removing from astqueueDavid Teigland
The lkb_ast_type field indicates whether the lkb is on the astqueue list. When clearing locks for a process, lkb's were being removed from the astqueue list without clearing the field. If release_lockspace then happened immediately afterward, it could try to remove the lkb from the list a second time. Appears when process calls libdlm dlm_release_lockspace() which first closes the ls dev triggering clear_proc_locks, and then removes the ls (a write to control dev) causing release_lockspace(). Signed-off-by: David Teigland <teigland@redhat.com>
2008-01-29dlm: use dlm prefix on alloc and free functionsDavid Teigland
The dlm functions in memory.c should use the dlm_ prefix. Also, use kzalloc/kfree directly for dlm_direntry's, removing the wrapper functions. Signed-off-by: David Teigland <teigland@redhat.com>
2008-01-29dlm: don't print common non-errorsDavid Teigland
Change log_error() to log_debug() for conditions that can occur in large number in normal operation. Signed-off-by: David Teigland <teigland@redhat.com>
2008-01-29dlm: proper prototypesAdrian Bunk
This patch adds a proper prototype for some functions in fs/dlm/dlm_internal.h Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: David Teigland <teigland@redhat.com>
2007-10-10[DLM] block dlm_recv in recovery transitionDavid Teigland
Introduce a per-lockspace rwsem that's held in read mode by dlm_recv threads while working in the dlm. This allows dlm_recv activity to be suspended when the lockspace transitions to, from and between recovery cycles. The specific bug prompting this change is one where an in-progress recovery cycle is aborted by a new recovery cycle. While dlm_recv was processing a recovery message, the recovery cycle was aborted and dlm_recoverd began cleaning up. dlm_recv decremented recover_locks_count on an rsb after dlm_recoverd had reset it to zero. This is fixed by suspending dlm_recv (taking write lock on the rwsem) before aborting the current recovery. The transitions to/from normal and recovery modes are simplified by using this new ability to block dlm_recv. The switch from normal to recovery mode means dlm_recv goes from processing locking messages, to saving them for later, and vice versa. Races are avoided by blocking dlm_recv when setting the flag that switches between modes. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10[DLM] don't overwrite castparam if it's NULLPatrick Caulfield
If the castaddr passed to the userland API is NULL then don't overwrite the existing castparam. This allows a different thread to cancel a lock request and the CANCEL AST gets delivered to the original thread. bz#306391 (for RHEL4) refers. Signed-Off-By: Patrick Caulfield <pcaulfie@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-08-14[DLM] fix basts for granted PR waiting CWDavid Teigland
Fix a long standing bug where a blocking callback would be missed when there's a granted lock in PR mode and waiting locks in both PR and CW modes (and the PR lock was added to the waiting queue before the CW lock). The logic simply compared the numerical values of the modes to determine if a blocking callback was required, but in the one case of PR and CW, the lower valued CW mode blocks the higher valued PR mode. We just need to add a special check for this PR/CW case in the tests that decide when a blocking callback is needed. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-07-09[DLM] variable allocationPatrick Caulfield
Add a new flag, DLM_LSFL_FS, to be used when a file system creates a lockspace. This flag causes the dlm to use GFP_NOFS for allocations instead of GFP_KERNEL. (This updated version of the patch uses gfp_t for ls_allocation.) Signed-Off-By: Patrick Caulfield <pcaulfie@redhat.com> Signed-Off-By: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-07-09[DLM] canceling deadlocked lockDavid Teigland
Add a function that can be used through libdlm by a system daemon to cancel another process's deadlocked lock. A completion ast with EDEADLK is returned to the process waiting for the lock. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-07-09[DLM] timeout fixesDavid Teigland
Various fixes related to the new timeout feature: - add_timeout() missed setting TIMEWARN flag on lkb's when the TIMEOUT flag was already set - clear_proc_locks should remove a dead process's locks from the timeout list - the end-of-life calculation for user locks needs to consider that ETIMEDOUT is equivalent to -DLM_ECANCEL - make initial default timewarn_cs config value visible in configfs - change bit position of TIMEOUT_CANCEL flag so it's not copied to a remote master node - set timestamp on remote lkb's so a lock dump will display the time they've been waiting Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-07-09[DLM] Compile fixSteven Whitehouse
A one liner fix which got missed from the earlier patches. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Cc: Fabio Massimo Di Nitto <fabbione@ubuntu.com> Cc: David Teigland <teigland@redhat.com>
2007-07-09[DLM] fix compile breakageDavid Teigland
In the rush to get the previous patch set sent, a compilation bug I fixed shortly before sending somehow got clobbered, probably by a missed quilt refresh or something. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-07-09[DLM] cancel in conversion deadlock [4/6]David Teigland
When conversion deadlock is detected, cancel the conversion and return EDEADLK to the application. This is a new default behavior where before the dlm would allow the deadlock to exist indefinately. The DLM_LKF_NODLCKWT flag can now be used in a conversion to prevent the dlm from performing conversion deadlock detection/cancelation on it. The DLM_LKF_CONVDEADLK flag can continue to be used as before to tell the dlm to demote the granted mode of the lock being converted if it gets into a conversion deadlock. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-07-09[DLM] dlm_device interface changes [3/6]David Teigland
Change the user/kernel device interface used by libdlm: - Add ability for userspace to check the version of the interface. libdlm can now adapt to different versions of the kernel interface. - Increase the size of the flags passed in a lock request so all possible flags can be used from userspace. - Add an opaque "xid" value for each lock. This "transaction id" will be used later to associate locks with each other during deadlock detection. - Add a "timeout" value for each lock. This is used along with the DLM_LKF_TIMEOUT flag. Also, remove a fragment of unused code in device_read(). This patch requires updating libdlm which is backward compatible with older kernels. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-07-09[DLM] add lock timeouts and warnings [2/6]David Teigland
New features: lock timeouts and time warnings. If the DLM_LKF_TIMEOUT flag is set, then the request/conversion will be canceled after waiting the specified number of centiseconds (specified per lock). This feature is only available for locks requested through libdlm (can be enabled for kernel dlm users if there's a use for it.) If the new DLM_LSFL_TIMEWARN flag is set when creating the lockspace, then a warning message will be sent to userspace (using genetlink) after a request/conversion has been waiting for a given number of centiseconds (configurable per node). The time warnings will be used in the future to do deadlock detection in userspace. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-07-09[DLM] block scand during recovery [1/6]David Teigland
Don't let dlm_scand run during recovery since it may try to do a resource directory removal while the directory nodes are changing. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-05-01[DLM] fix mode mungingDavid Teigland
There are flags to enable two specialized features in the dlm: 1. CONVDEADLK causes the dlm to resolve conversion deadlocks internally by changing the granted mode of locks to NL. 2. ALTPR/ALTCW cause the dlm to change the requested mode of locks to PR or CW to grant them if the normal requested mode can't be granted. GFS direct i/o exercises both of these features, especially when mixed with buffered i/o. The dlm has problems with them. The first problem is on the master node. If it demotes a lock as a part of converting it, the actual step of converting the lock isn't being done after the demotion, the lock is just left sitting on the granted queue with a granted mode of NL. I think the mistaken assumption was that the call to grant_pending_locks() would grant it, but that function naturally doesn't look at locks on the granted queue. The second problem is on the process node. If the master either demotes or gives an altmode, the munging of the gr/rq modes is never done in the process copy of the lock, leaving the master/process copies out of sync. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-05-01[DLM] change lkid formatDavid Teigland
A lock id is a uint32 and is used as an opaque reference to the lock. For userland apps, the lkid is passed up, through libdlm, as the return value from a write() on the dlm device. This created a problem when the high bit was 1, making the lkid look like an error. This is fixed by changing how the lkid is composed. The low 16 bits identified the hash bucket for the lock and the high 16 bits were a per-bucket counter (which eventually hit 0x8000 causing the problem). These are simply swapped around; the number of hash table buckets is far below 0x8000, making all lkid's positive when viewed as signed. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-05-01[DLM] add orphan purging code (1/2)David Teigland
Add code for purging orphan locks. A process can also purge all of its own non-orphan locks by passing a pid of zero. Code already exists for processes to create persistent locks that become orphans when the process exits, but the complimentary capability for another process to then purge these orphans has been missing. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-05-01[DLM] split create_message functionDavid Teigland
This splits the current create_message() function into two parts so that later patches can call the new lower-level _create_message() function when they don't have an rsb struct. No functional change in this patch. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-05-01[DLM] overlapping cancel and unlockDavid Teigland
Full cancel and force-unlock support. In the past, cancel and force-unlock wouldn't work if there was another operation in progress on the lock. Now, both cancel and unlock-force can overlap an operation on a lock, meaning there may be 2 or 3 operations in progress on a lock in parallel. This support is important not only because cancel and force-unlock are explicit operations that an app can use, but both are used implicitly when a process exits while holding locks. Summary of changes: - add-to and remove-from waiters functions were rewritten to handle situations with more than one remote operation outstanding on a lock - validate_unlock_args detects when an overlapping cancel/unlock-force can be sent and when it needs to be delayed until a request/lookup reply is received - processing request/lookup replies detects when cancel/unlock-force occured during the op, and carries out the delayed cancel/unlock-force - manipulation of the "waiters" (remote operation) state of a lock moved under the standard rsb mutex that protects all the other lock state - the two recovery routines related to locks on the waiters list changed according to the way lkb's are now locked before accessing waiters state - waiters recovery detects when lkb's being recovered have overlapping cancel/unlock-force, and may not recover such locks - revert_lock (cancel) returns a value to distinguish cases where it did nothing vs cases where it actually did a cancel; the cancel completion ast should only be done when cancel did something - orphaned locks put on new list so they can be found later for purging - cancel must be called on a lock when making it an orphan - flag user locks (ENDOFLIFE) at the end of their useful life (to the application) so we can return an error for any further cancel/unlock-force - we weren't setting COMP/BAST ast flags if one was already set, so we'd lose either a completion or blocking ast - clear an unread bast on a lock that's become unlocked Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-02-05[DLM] zero new user lvbsDavid Teigland
A new lvb for a userland lock wasn't being initialized to zero. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-02-05[DLM] can miss clearing resend flagDavid Teigland
A long, complicated sequence of events, beginning with the RESEND flag not being cleared on an lkb, can result in an unlock never completing. - lkb on waiters list for remote lookup - the remote node is both the dir node and the master node, so it optimizes the lookup into a request and sends a request reply back - the request reply is saved on the requestqueue to be processed after recovery - recovery runs dlm_recover_waiters_pre() which sets RESEND flag so the lookup will be resent after recovery - end of recovery: process_requestqueue takes saved request reply which removes the lkb off the waitesr list, _without_ clearing the RESEND flag - end of recovery: dlm_recover_waiters_post() doesn't do anything with the now completed lookup lkb (would usually clear RESEND) - later, the node unmounts, unlocks this lkb that still has RESEND flag set - the lkb is on the waiters list again, now for unlock, when recovery occurs, dlm_recover_waiters_pre() shows the lkb for unlock with RESEND set, doesn't do anything since the master still exists - end of recovery: dlm_recover_waiters_post() takes this lkb off the waiters list because it has the RESEND flag set, then reports an error because unlocks are never supposed to be handled in recover_waiters_post(). - later, the unlock reply is received, doesn't find the lkb on the waiters list because recover_waiters_post() has wrongly removed it. - the unlock operation has been lost, and we're left with a stray granted lock - unmount spins waiting for the unlock to complete The visible evidence of this problem will be a node where gfs umount is spinning, the dlm waiters list will be empty, and the dlm locks list will show a granted lock. The fix is simply to clear the RESEND flag when taking an lkb off the waiters list. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-02-05[DLM] saved dlm message can be droppedDavid Teigland
dlm_receive_message() returns 0 instead of returning 'error'. What would happen is that process_requestqueue would take a saved message off the requestqueue and call receive_message on it. receive_message would then see that recovery had been aborted, set error to EINTR, and 'goto out', expecting that the error would be returned. Instead, 0 was always returned, so process_requestqueue would think that the message had been processed and delete it instead of saving it to process next time. This means the message (usually an unlock in my tests) would be lost. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-02-05[DLM] fix user unlockingDavid Teigland
When a user process exits, we clear all the locks it holds. There is a problem, though, with locks that the process had begun unlocking before it exited. We couldn't find the lkb's that were in the process of being unlocked remotely, to flag that they are DEAD. To solve this, we move lkb's being unlocked onto a new list in the per-process structure that tracks what locks the process is holding. We can then go through this list to flag the necessary lkb's when clearing locks for a process when it exits. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>