linux/fs/gfs2/glock.c, branch v2.6.38

workqueue, freezer: unify spelling of 'freeze' + 'able' to 'freezable'

2011-02-16T16:48:59Z

There are two spellings in use for 'freeze' + 'able' - 'freezable' and 'freezeable'. The former is the more prominent one. The latter is mostly used by workqueue and in a few other odd places. Unify the spelling to 'freezable'. Signed-off-by: Tejun Heo Reported-by: Alan Stern Acked-by: "Rafael J. Wysocki" Acked-by: Greg Kroah-Hartman Acked-by: Dmitry Torokhov Cc: David Woodhouse Cc: Alex Dubov Cc: "David S. Miller" Cc: Steven Whitehouse

GFS2: Merge glock state fields into a bitfield

2010-11-30T15:49:31Z

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 Cc: Bob Peterson

GFS2: Clean up of gdlm_lock function

2010-11-30T10:31:48Z

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

GFS2: fs/gfs2/glock.c: Use printf extension %pV

2010-11-30T10:30:41Z

Using %pV reduces the number of printk calls and eliminates any possible message interleaving from other printk calls. Signed-off-by: Joe Perches Signed-off-by: Steven Whitehouse

GFS2: fs/gfs2/glock.c: Convert sprintf_symbol to %pS

2010-11-30T10:22:19Z

Signed-off-by: Joe Perches Signed-off-by: Steven Whitehouse

GFS2: Change two WQ_RESCUERs into WQ_MEM_RECLAIM

2010-11-30T10:21:55Z

The WQ_RESCUER flag should only be used internally to the workqueue implementation. Signed-off-by: Steven Whitehouse Acked-by: Tejun Heo

GFS2: Fix inode deallocation race

2010-11-15T12:44:42Z

This area of the code has always been a bit delicate due to the subtleties of lock ordering. The problem is that for "normal" alloc/dealloc, we always grab the inode locks first and the rgrp lock later. In order to ensure no races in looking up the unlinked, but still allocated inodes, we need to hold the rgrp lock when we do the lookup, which means that we can't take the inode glock. The solution is to borrow the technique already used by NFS to solve what is essentially the same problem (given an inode number, look up the inode carefully, checking that it really is in the expected state). We cannot do that directly from the allocation code (lock ordering again) so we give the job to the pre-existing delete workqueue and carry on with the allocation as normal. If we find there is no space, we do a journal flush (required anyway if space from a deallocation is to be released) which should block against the pending deallocations, so we should always get the space back. Signed-off-by: Steven Whitehouse

GFS2: Fix spectator umount issue

2010-09-29T13:20:52Z

The tests further down the recovery function relating to unlocking the journal need to be updated to match the intial test. Also, a test in the umount code which was surplus to requirements has been removed. Umounting spectator mounts now works correctly, as expected. Signed-off-by: Steven Whitehouse

GFS2: Use new workqueue scheme

2010-09-20T10:20:36Z

The recovery workqueue can be freezable since we want it to finish what it is doing if the system is to be frozen (although why you'd want to freeze a cluster node is beyond me since it will result in it being ejected from the cluster). It does still make sense for single node GFS2 filesystems though. The glock workqueue will benefit from being able to run more work items concurrently. A test running postmark shows improved performance and multi-threaded workloads are likely to benefit even more. It needs to be high priority because the latency directly affects the latency of filesystem glock operations. The delete workqueue is similar to the recovery workqueue in that it must not get blocked by memory allocations, and may run for a long time. Potentially other GFS2 threads might also be converted to workqueues, but I'll leave that for a later patch. Signed-off-by: Steven Whitehouse Acked-by: Tejun Heo

GFS2: Don't enforce min hold time when two demotes occur in rapid succession

2010-09-20T10:19:50Z

Due to the design of the VFS, it is quite usual for operations on GFS2 to consist of a lookup (requiring a shared lock) followed by an operation requiring an exclusive lock. If a remote node has cached an exclusive lock, then it will receive two demote events in rapid succession firstly for a shared lock and then to unlocked. The existing min hold time code was triggering in this case, even if the node was otherwise idle since the state change time was being updated by the initial demote. This patch introduces logic to skip the min hold timer in the case that a "double demote" of this kind has occurred. The min hold timer will still be used in all other cases. A new glock flag is introduced which is used to keep track of whether there have been any newly queued holders since the last glock state change. The min hold time is only applied if the flag is set. Signed-off-by: Steven Whitehouse Tested-by: Abhijith Das