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path: root/fs/dlm/lock.h
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2014-11-19dlm: adopt orphan locksDavid Teigland
A process may exit, leaving an orphan lock in the lockspace. This adds the capability for another process to acquire the orphan lock. Acquiring the orphan just moves the lock from the orphan list onto the acquiring process's list of locks. An adopting process must specify the resource name and mode of the lock it wants to adopt. If a matching lock is found, the lock is moved to the caller's 's list of locks, and the lkid of the lock is returned like the lkid of a new lock. If an orphan with a different mode is found, then -EAGAIN is returned. If no orphan lock is found on the resource, then -ENOENT is returned. No async completion is used because the result is immediately available. Also, when orphans are purged, allow a zero nodeid to refer to the local nodeid so the caller does not need to look up the local nodeid. Signed-off-by: David Teigland <teigland@redhat.com>
2012-07-16dlm: use rsbtbl as resource directoryDavid Teigland
Remove the dir hash table (dirtbl), and use the rsb hash table (rsbtbl) as the resource directory. It has always been an unnecessary duplication of information. This improves efficiency by using a single rsbtbl lookup in many cases where both rsbtbl and dirtbl lookups were needed previously. This eliminates the need to handle cases of rsbtbl and dirtbl being out of sync. In many cases there will be memory savings because the dir hash table no longer exists. Signed-off-by: David Teigland <teigland@redhat.com>
2012-05-02dlm: fixes for nodir modeDavid Teigland
The "nodir" mode (statically assign master nodes instead of using the resource directory) has always been highly experimental, and never seriously used. This commit fixes a number of problems, making nodir much more usable. - Major change to recovery: recover all locks and restart all in-progress operations after recovery. In some cases it's not possible to know which in-progess locks to recover, so recover all. (Most require recovery in nodir mode anyway since rehashing changes most master nodes.) - Change the way nodir mode is enabled, from a command line mount arg passed through gfs2, into a sysfs file managed by dlm_controld, consistent with the other config settings. - Allow recovering MSTCPY locks on an rsb that has not yet been turned into a master copy. - Ignore RCOM_LOCK and RCOM_LOCK_REPLY recovery messages from a previous, aborted recovery cycle. Base this on the local recovery status not being in the state where any nodes should be sending LOCK messages for the current recovery cycle. - Hold rsb lock around dlm_purge_mstcpy_locks() because it may run concurrently with dlm_recover_master_copy(). - Maintain highbast on process-copy lkb's (in addition to the master as is usual), because the lkb can switch back and forth between being a master and being a process copy as the master node changes in recovery. - When recovering MSTCPY locks, flag rsb's that have non-empty convert or waiting queues for granting at the end of recovery. (Rename flag from LOCKS_PURGED to RECOVER_GRANT and similar for the recovery function, because it's not only resources with purged locks that need grant a grant attempt.) - Replace a couple of unnecessary assertion panics with error messages. Signed-off-by: David Teigland <teigland@redhat.com>
2012-04-26dlm: improve error and debug messagesDavid Teigland
Change some existing error/debug messages to collect more useful information, and add some new error/debug messages to address recently found problems. Signed-off-by: David Teigland <teigland@redhat.com>
2012-03-08dlm: fix slow rsb search in dir recoveryDavid Teigland
The function used to find an rsb during directory recovery was searching the single linear list of rsb's. This wasted a lot of time compared to using the standard hash table to find the rsb. Signed-off-by: David Teigland <teigland@redhat.com>
2011-04-01dlm: delayed reply message warningDavid Teigland
Add an option (disabled by default) to print a warning message when a lock has been waiting a configurable amount of time for a reply message from another node. This is mainly for debugging. 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>
2008-02-04dlm: 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>
2008-01-30dlm: 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>
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>
2007-07-09[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] 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] interface for purge (2/2)David Teigland
Add code to accept purge commands from userland. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-08-21[DLM] dump rsb and locks on assertDavid Teigland
Introduce new function dlm_dump_rsb() to call within assertions instead of dlm_print_rsb(). The new function dumps info about all locks on the rsb in addition to rsb details. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-07-13[DLM] dlm: user locksDavid Teigland
This changes the way the dlm handles user locks. The core dlm is now aware of user locks so they can be dealt with more efficiently. There is no more dlm_device module which previously managed its own duplicate copy of every user lock. Signed-off-by: Patrick Caulfield <pcaulfie@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-05-02[DLM] fix grant_after_purge softlockupDavid Teigland
In dlm_grant_after_purge() we were holding a hash table read_lock while calling put_rsb() which potentially removes the rsb from the hash table, taking the same lock in write. Fix this by flagging rsb's ahead of time that have been purged. Then iteratively read_lock the hash table, find a flagged rsb, unlock, process rsb. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-01-20[DLM] Update DLM to the latest patch levelDavid Teigland
Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steve Whitehouse <swhiteho@redhat.com>
2006-01-18[DLM] The core of the DLM for GFS2/CLVMDavid Teigland
This is the core of the distributed lock manager which is required to use GFS2 as a cluster filesystem. It is also used by CLVM and can be used as a standalone lock manager independantly of either of these two projects. It implements VAX-style locking modes. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steve Whitehouse <swhiteho@redhat.com>