path: root/fs/gfs2/lock_dlm.c
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2013-01-28GFS2: fix skip unlock conditionDavid Teigland1-1/+6
The recent commit fb6791d100d1bba20b5cdbc4912e1f7086ec60f8 included the wrong logic. The lvbptr check was incorrectly added after the patch was tested. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-01-02GFS2: Initialize hex string to '0'Nathan Straz1-0/+1
When generating the DLM lock name, a value of 0 would skip the loop and leave the string unchanged. This left locks with a value of 0 unlabeled. Initializing the string to '0' fixes this. Signed-off-by: Nathan Straz <nstraz@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-11-15GFS2: remove redundant lvb pointerDavid Teigland1-4/+4
The lksb struct already contains a pointer to the lvb, so another directly from the glock struct is not needed. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-11-15GFS2: only use lvb on glocks that need itDavid Teigland1-5/+7
Save the effort of allocating, reading and writing the lvb for most glocks that do not use it. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-11-14GFS2: skip dlm_unlock calls in unmountDavid Teigland1-0/+8
When unmounting, gfs2 does a full dlm_unlock operation on every cached lock. This can create a very large amount of work and can take a long time to complete. However, the vast majority of these dlm unlock operations are unnecessary because after all the unlocks are done, gfs2 leaves the dlm lockspace, which automatically clears the locks of the leaving node, without unlocking each one individually. So, gfs2 can skip explicit dlm unlocks, and use dlm_release_lockspace to remove the locks implicitly. The one exception is when the lock's lvb is being used. In this case, dlm_unlock is called because it may update the lvb of the resource. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-08-20workqueue: deprecate flush[_delayed]_work_sync()Tejun Heo1-1/+1
flush[_delayed]_work_sync() are now spurious. Mark them deprecated and convert all users to flush[_delayed]_work(). If you're cc'd and wondering what's going on: Now all workqueues are non-reentrant and the regular flushes guarantee that the work item is not pending or running on any CPU on return, so there's no reason to use the sync flushes at all and they're going away. This patch doesn't make any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Mattia Dongili <malattia@linux.it> Cc: Kent Yoder <key@linux.vnet.ibm.com> Cc: David Airlie <airlied@linux.ie> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Karsten Keil <isdn@linux-pingi.de> Cc: Bryan Wu <bryan.wu@canonical.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mauro Carvalho Chehab <mchehab@infradead.org> Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de> Cc: David Woodhouse <dwmw2@infradead.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: linux-wireless@vger.kernel.org Cc: Anton Vorontsov <cbou@mail.ru> Cc: Sangbeom Kim <sbkim73@samsung.com> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Petr Vandrovec <petr@vandrovec.name> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Avi Kivity <avi@redhat.com>
2012-05-02dlm: fixes for nodir modeDavid Teigland1-2/+0
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>
2012-04-24GFS2: Instruct DLM to avoid queue convert slowdownBob Peterson1-3/+7
This patch instructs DLM to prevent an "in place" conversion, where the lock just stays on the granted queue, and instead forces the conversion to the back of the convert queue. This is done on upward conversions only. This is useful in cases where, for example, a lock is frequently needed in PR on one node, but another node needs it temporarily in EX to update it. This may happen, for example, when the rindex is being updated by gfs2_grow. The gfs2_grow needs to have the lock in EX, but the other nodes need to re-read it to retrieve the updates. The glock is already granted in PR on the non-growing nodes, so this prevents them from continually re-granting the lock in PR, and forces the EX from gfs2_grow to go through. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-02-28GFS2: glock statistics gatheringSteven Whitehouse1-5/+118
The stats are divided into two sets: those relating to the super block and those relating to an individual glock. The super block stats are done on a per cpu basis in order to try and reduce the overhead of gathering them. They are also further divided by glock type. In the case of both the super block and glock statistics, the same information is gathered in each case. The super block statistics are used to provide default values for most of the glock statistics, so that newly created glocks should have, as far as possible, a sensible starting point. The statistics are divided into three pairs of mean and variance, plus two counters. The mean/variance pairs are smoothed exponential estimates and the algorithm used is one which will be very familiar to those used to calculation of round trip times in network code. The three pairs of mean/variance measure the following things: 1. DLM lock time (non-blocking requests) 2. DLM lock time (blocking requests) 3. Inter-request time (again to the DLM) A non-blocking request is one which will complete right away, whatever the state of the DLM lock in question. That currently means any requests when (a) the current state of the lock is exclusive (b) the requested state is either null or unlocked or (c) the "try lock" flag is set. A blocking request covers all the other lock requests. There are two counters. The first is there primarily to show how many lock requests have been made, and thus how much data has gone into the mean/variance calculations. The other counter is counting queueing of holders at the top layer of the glock code. Hopefully that number will be a lot larger than the number of dlm lock requests issued. So why gather these statistics? There are several reasons we'd like to get a better idea of these timings: 1. To be able to better set the glock "min hold time" 2. To spot performance issues more easily 3. To improve the algorithm for selecting resource groups for allocation (to base it on lock wait time, rather than blindly using a "try lock") Due to the smoothing action of the updates, a step change in some input quantity being sampled will only fully be taken into account after 8 samples (or 4 for the variance) and this needs to be carefully considered when interpreting the results. Knowing both the time it takes a lock request to complete and the average time between lock requests for a glock means we can compute the total percentage of the time for which the node is able to use a glock vs. time that the rest of the cluster has its share. That will be very useful when setting the lock min hold time. The other point to remember is that all times are in nanoseconds. Great care has been taken to ensure that we measure exactly the quantities that we want, as accurately as possible. There are always inaccuracies in any measuring system, but I hope this is as accurate as we can reasonably make it. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-01-11GFS2: dlm based recovery coordinationDavid Teigland1-10/+983
This new method of managing recovery is an alternative to the previous approach of using the userland gfs_controld. - use dlm slot numbers to assign journal id's - use dlm recovery callbacks to initiate journal recovery - use a dlm lock to determine the first node to mount fs - use a dlm lock to track journals that need recovery Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-01-04dlm: add recovery callbacksDavid Teigland1-2/+2
These new callbacks notify the dlm user about lock recovery. GFS2, and possibly others, need to be aware of when the dlm will be doing lock recovery for a failed lockspace member. In the past, this coordination has been done between dlm and file system daemons in userspace, which then direct their kernel counterparts. These callbacks allow the same coordination directly, and more simply. Signed-off-by: David Teigland <teigland@redhat.com>
2011-03-09GFS2: Fix glock deallocation raceSteven Whitehouse1-2/+2
This patch fixes a race in deallocating glocks which was introduced in the RCU glock patch. We need to ensure that the glock count is kept correct even in the case that there is a race to add a new glock into the hash table. Also, to avoid having to wait for an RCU grace period, the glock counter can be decremented before call_rcu() is called. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2011-01-21GFS2: Use RCU for glock hash tableSteven Whitehouse1-11/+3
This has a number of advantages: - Reduces contention on the hash table lock - Makes the code smaller and simpler - Should speed up glock dumps when under load - Removes ref count changing in examine_bucket - No longer need hash chain lock in glock_put() in common case There are some further changes which this enables and which we may do in the future. One is to look at using SLAB_RCU, and another is to look at using a per-cpu counter for the per-sb glock counter, since that is touched twice in the lifetime of each glock (but only used at umount time). Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2010-11-30GFS2: Merge glock state fields into a bitfieldSteven Whitehouse1-1/+0
We can only merge the fields into a bitfield if the locking rules for them are the same. In this case gl_spin covers all of the fields (write side) but a couple of them are used with GLF_LOCK as the read side lock, which should be ok since we know that the field in question won't be changing at the time. The gl_req setting has to be done earlier (in glock.c) in order to place it under gl_spin. The gl_reply setting also has to be brought under gl_spin in order to comply with the new rules. This saves 4*sizeof(unsigned int) per glock. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Cc: Bob Peterson <rpeterso@redhat.com>
2010-11-30GFS2: Clean up of gdlm_lock functionSteven Whitehouse1-10/+4
The DLM never returns -EAGAIN in response to dlm_lock(), and even if it did, the test in gdlm_lock() was wrong anyway. Once that test is removed, it is possible to greatly simplify this code by simply using a "normal" error return code (0 for success). We then no longer need the LM_OUT_ASYNC return code which can be removed. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2010-09-20GFS2: Update handling of DLM return codes to match realitySteven Whitehouse1-2/+2
GFS2's idea of which return codes it needs to handle was based upon those listed in dlm.h. Those didn't cover all the possible codes and listed some which never happen. This updates GFS2 to handle all the codes which can actually be returned from the DLM under various circumstances. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo1-0/+1
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-01GFS2: Metadata address space clean upSteven Whitehouse1-1/+4
Since the start of GFS2, an "extra" inode has been used to store the metadata belonging to each inode. The only reason for using this inode was to have an extra address space, the other fields were unused. This means that the memory usage was rather inefficient. The reason for keeping each inode's metadata in a separate address space is that when glocks are requested on remote nodes, we need to be able to efficiently locate the data and metadata which relating to that glock (inode) in order to sync or sync and invalidate it (depending on the remotely requested lock mode). This patch adds a new type of glock, which has in addition to its normal fields, has an address space. This applies to all inode and rgrp glocks (but to no other glock types which remain as before). As a result, we no longer need to have the second inode. This results in three major improvements: 1. A saving of approx 25% of memory used in caching inodes 2. A removal of the circular dependency between inodes and glocks 3. No confusion between "normal" and "metadata" inodes in super.c Although the first of these is the more immediately apparent, the second is just as important as it now enables a number of clean ups at umount time. Those will be the subject of future patches. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2010-02-03GFS2: Extend umount wait coverage to full glock lifetimeSteven Whitehouse1-3/+3
Although all glocks are, by the time of the umount glock wait, scheduled for demotion, some of them haven't made it far enough through the process for the original set of waiting code to wait for them. This extends the ref count to the whole glock lifetime in order to ensure that the waiting does catch all glocks. It does make it a bit more invasive, but it seems the only sensible solution at the moment. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2010-02-03GFS2: Wait for unlock completion on umountSteven Whitehouse1-1/+6
This patch adds a wait on umount between the point at which we dispose of all glocks and the point at which we unmount the lock protocol. This ensures that we've received all the replies to our unlock requests before we stop the locking. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Reported-by: Fabio M. Di Nitto <fdinitto@redhat.com>
2009-03-24GFS2: Fix locking bug in failed shared to exclusive conversionBenjamin Marzinski1-3/+4
After calling out to the dlm, GFS2 sets the new state of a glock to gl_target in gdlm_ast(). However, gl_target is not always the lock state that was requested. If a conversion from shared to exclusive fails, finish_xmote() will call do_xmote() with LM_ST_UNLOCKED, instead of gl->gl_target, so that it can reacquire the lock in exlusive the next time around. In this case, setting the lock to gl_target in gdlm_ast() will make GFS2 think that it has the glock in exclusive mode, when really, it doesn't have the glock locked at all. This patch adds a new field to the gfs2_glock structure, gl_req, to track the mode that was requested. Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-03-24GFS2: Merge lock_dlm module into GFS2Steven Whitehouse1-0/+240
This is the big patch that I've been working on for some time now. There are many reasons for wanting to make this change such as: o Reducing overhead by eliminating duplicated fields between structures o Simplifcation of the code (reduces the code size by a fair bit) o The locking interface is now the DLM interface itself as proposed some time ago. o Fewer lookups of glocks when processing replies from the DLM o Fewer memory allocations/deallocations for each glock o Scope to do further optimisations in the future (but this patch is more than big enough for now!) Please note that (a) this patch relates to the lock_dlm module and not the DLM itself, that is still a separate module; and (b) that we retain the ability to build GFS2 as a standalone single node filesystem with out requiring the DLM. This patch needs a lot of testing, hence my keeping it I restarted my -git tree after the last merge window. That way, this has the maximum exposure before its merged. This is (modulo a few minor bug fixes) the same patch that I've been posting on and off the the last three months and its passed a number of different tests so far. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>