Commit Graph

243 Commits

Author SHA1 Message Date
Bob Peterson ff34245d52 GFS2: Don't filter out I_FREEING inodes anymore
This patch basically reverts a very old patch from 2008,
7a9f53b3c1, with the title
"Alternate gfs2_iget to avoid looking up inodes being freed".
The original patch was designed to avoid a deadlock caused by lock
ordering with try_rgrp_unlink. The patch forced the function to not
find inodes that were being removed by VFS. The problem is, that
made it impossible for nodes to delete their own unlinked dinodes
after a certain point in time, because the inode needed was not found
by this filtering process. There is no longer a need for the patch,
since function try_rgrp_unlink no longer locks the inode: All it does
is queue the glock onto the delete work_queue, so there should be no
more deadlock.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2016-03-15 10:46:45 -04:00
Bob Peterson a4923865ea GFS2: Prevent delete work from occurring on glocks used for create
This patch tries to prevent delete work (queued via iopen callback)
from executing if the glock is currently being used to create
a new inode.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
2016-03-15 10:46:37 -04:00
Bob Peterson 7508abc4bd GFS2: Check if iopen is held when deleting inode
This patch fixes an error condition in which an inode is partially
created in gfs2_create_inode() but then some error is discovered,
which causes it to fail and call iput() before the iopen glock is
created or held. In that case, gfs2_delete_inode would try to
unlock an iopen glock that doesn't yet exist. Therefore, we test
its holder (which must exist) for the HIF_HOLDER bit before trying
to dq it.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
2016-01-14 08:47:42 -05:00
Bob Peterson 2aba1b5b4f GFS2: Reintroduce a timeout in function gfs2_gl_hash_clear
At some point in the past, we used to have a timeout when GFS2 was
unmounting, trying to clear out its glocks. If the timeout expires,
it would dump the remaining glocks to the kernel messages so that
developers can debug the problem. That timeout was eliminated,
probably by accident. This patch reintroduces it.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2015-12-14 12:19:31 -06:00
Bob Peterson b58bf407ca GFS2: Reduce size of incore inode
This patch makes no functional changes. Its goal is to reduce the
size of the gfs2 inode in memory by rearranging structures and
changing the size of some variables within the structure.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2015-12-14 12:19:24 -06:00
Andrew Price 3dd1dd8c69 GFS2: Use rht_for_each_entry_rcu in glock_hash_walk
This lockdep splat was being triggered on umount:

[55715.973122] ===============================
[55715.980169] [ INFO: suspicious RCU usage. ]
[55715.981021] 4.3.0-11553-g8d3de01-dirty #15 Tainted: G        W
[55715.982353] -------------------------------
[55715.983301] fs/gfs2/glock.c:1427 suspicious rcu_dereference_protected() usage!

The code it refers to is the rht_for_each_entry_safe usage in
glock_hash_walk. The condition that triggers the warning is
lockdep_rht_bucket_is_held(tbl, hash) which is checked in the
__rcu_dereference_protected macro.

The rhashtable buckets are not changed in glock_hash_walk so it's safe
to rely on the rcu protection. Replace the rht_for_each_entry_safe()
usage with rht_for_each_entry_rcu(), which doesn't care whether the
bucket lock is held if the rcu read lock is held.

Signed-off-by: Andrew Price <anprice@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
2015-11-16 11:57:59 -06:00
Andreas Gruenbacher f3dd164912 gfs2: Remove gl_spin define
Commit e66cf161 replaced the gl_spin spinlock in struct gfs2_glock with a
gl_lockref lockref and defined gl_spin as gl_lockref.lock (the spinlock in
gl_lockref).  Remove that define to make the references to gl_lockref.lock more
obvious.

Signed-off-by: Andreas Gruenbacher <andreas.gruenbacher@gmail.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2015-10-29 12:57:48 -05:00
Andreas Gruenbacher 8f7e0a806d gfs2: A minor "sbstats" cleanup
It seems cleaner to avoid the temporary value here.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2015-09-03 13:34:14 -05:00
Ben Hutchings 4d207133e9 gfs2: Make statistics unsigned, suitable for use with do_div()
None of these statistics can meaningfully be negative, and the
numerator for do_div() must have the type u64.  The generic
implementation of do_div() used on some 32-bit architectures asserts
that, resulting in a compiler error in gfs2_rgrp_congested().

Fixes: 0166b197c2 ("GFS2: Average in only non-zero round-trip times ...")

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Acked-by: Andreas Gruenbacher <agruenba@redhat.com>
2015-09-03 13:33:32 -05:00
Bob Peterson 88ffbf3e03 GFS2: Use resizable hash table for glocks
This patch changes the glock hash table from a normal hash table to
a resizable hash table, which scales better. This also simplifies
a lot of code.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
2015-09-03 13:33:24 -05:00
Bob Peterson 15562c439d GFS2: Move glock superblock pointer to field gl_name
What uniquely identifies a glock in the glock hash table is not
gl_name, but gl_name and its superblock pointer. This patch makes
the gl_name field correspond to a unique glock identifier. That will
allow us to simplify hashing with a future patch, since the hash
algorithm can then take the gl_name and hash its components in one
operation.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
2015-09-03 13:33:09 -05:00
Andreas Gruenbacher 81648d0431 gfs2: Simplify the seq file code for "sbstats"
Don't use struct gfs2_glock_iter as the helper data structure for iterating
through "sbstats"; we are not iterating through glocks here.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2015-09-03 13:33:05 -05:00
Bob Peterson e7ccaf5fe1 GFS2: Don't add all glocks to the lru
The glocks used for resource groups often come and go hundreds of
thousands of times per second. Adding them to the lru list just
adds unnecessary contention for the lru_lock spin_lock, especially
considering we're almost certainly going to re-use the glock and
take it back off the lru microseconds later. We never want the
glock shrinker to cull them anyway. This patch adds a new bit in
the glops that determines which glock types get put onto the lru
list and which ones don't.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
2015-06-18 12:17:59 -05:00
Chengyu Song 7b4ddfa7c9 gfs2: incorrect check for debugfs returns
debugfs_create_dir and debugfs_create_file may return -ENODEV when debugfs
is not configured, so the return value should be checked against ERROR_VALUE
as well, otherwise the later dereference of the dentry pointer would crash
the kernel.

Signed-off-by: Chengyu Song <csong84@gatech.edu>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
2015-03-30 09:13:29 -05:00
Linus Torvalds 6bec003528 Merge branch 'for-3.20/bdi' of git://git.kernel.dk/linux-block
Pull backing device changes from Jens Axboe:
 "This contains a cleanup of how the backing device is handled, in
  preparation for a rework of the life time rules.  In this part, the
  most important change is to split the unrelated nommu mmap flags from
  it, but also removing a backing_dev_info pointer from the
  address_space (and inode), and a cleanup of other various minor bits.

  Christoph did all the work here, I just fixed an oops with pages that
  have a swap backing.  Arnd fixed a missing export, and Oleg killed the
  lustre backing_dev_info from staging.  Last patch was from Al,
  unexporting parts that are now no longer needed outside"

* 'for-3.20/bdi' of git://git.kernel.dk/linux-block:
  Make super_blocks and sb_lock static
  mtd: export new mtd_mmap_capabilities
  fs: make inode_to_bdi() handle NULL inode
  staging/lustre/llite: get rid of backing_dev_info
  fs: remove default_backing_dev_info
  fs: don't reassign dirty inodes to default_backing_dev_info
  nfs: don't call bdi_unregister
  ceph: remove call to bdi_unregister
  fs: remove mapping->backing_dev_info
  fs: export inode_to_bdi and use it in favor of mapping->backing_dev_info
  nilfs2: set up s_bdi like the generic mount_bdev code
  block_dev: get bdev inode bdi directly from the block device
  block_dev: only write bdev inode on close
  fs: introduce f_op->mmap_capabilities for nommu mmap support
  fs: kill BDI_CAP_SWAP_BACKED
  fs: deduplicate noop_backing_dev_info
2015-02-12 13:50:21 -08:00
Christoph Hellwig b83ae6d421 fs: remove mapping->backing_dev_info
Now that we never use the backing_dev_info pointer in struct address_space
we can simply remove it and save 4 to 8 bytes in every inode.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Reviewed-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-01-20 14:03:05 -07:00
Bob Peterson 8f6cb409f0 GFS2: Eliminate __gfs2_glock_remove_from_lru
Since the only caller of function __gfs2_glock_remove_from_lru locks the
same spin_lock as gfs2_glock_remove_from_lru, the functions can be combined.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2015-01-09 11:33:13 +00:00
Markus Elfring 30badc9543 GFS2: Deletion of unnecessary checks before two function calls
The functions iput() and put_pid() test whether their argument is NULL
and then return immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2014-11-18 10:57:58 +00:00
Fabian Frederick d29c0afe4d GFS2: use _RET_IP_ instead of (unsigned long)__builtin_return_address(0)
use macro definition

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2014-10-08 09:57:07 +01:00
Ingo Molnar ca5bc6cd5d Merge branch 'sched/urgent' into sched/core, to merge fixes before applying new changes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-07-28 10:03:00 +02:00
Bob Peterson 5bef3e7cf1 GFS2: Allow flocks to use normal glock dq rather than dq_wait
This patch allows flock glocks to use a non-blocking dequeue rather
than dq_wait. It also reverts the previous patch I had posted regarding
dq_wait. The reverted patch isn't necessarily a bad idea, but I decided
this might avoid unforeseen side effects, and was therefore safer.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2014-07-18 11:13:56 +01:00
Steven Whitehouse fe0bbd2986 GFS2: Use GFP_NOFS when allocating glocks
Normally GFP_KERNEL is ok here, but there is now a rarely used code path
relating to deallocation of unlinked inodes (in certain corner cases)
which if hit at times of memory shortage can cause recursion while
trying to free memory.

One solution would be to try and move the gfs2_glock_get() call so
that it is no longer called while another glock is held, but that
doesn't look at all easy, so GFP_NOFS is the best solution for the
time being.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2014-07-18 11:13:12 +01:00
Steven Whitehouse 94a09a3999 GFS2: Fix race in glock lru glock disposal
We must not leave items on the LRU list with GLF_LOCK set, since
they can be removed if the glock is brought back into use, which
may then potentially result in a hang, waiting for GLF_LOCK to
clear.

It doesn't happen very often, since it requires a glock that has
not been used for a long time to be brought back into use at the
same moment that the shrinker is part way through disposing of
glocks.

The fix is to set GLF_LOCK at a later time, when we already know
that the other locks can be obtained. Also, we now only release
the lru_lock in case a resched is needed, rather than on every
iteration.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2014-07-18 11:12:51 +01:00
Bob Peterson 79272b3562 GFS2: Only wait for demote when last holder is dequeued
Function gfs2_glock_dq_wait is supposed to dequeue a glock and then
wait for the lock to be demoted. The problem is, if this is a shared
lock, its demote will depend on the other holders, which means you
might end up waiting forever because the other process is blocked.
This problem is especially apparent when dealing with nested flocks.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2014-07-18 11:12:14 +01:00
NeilBrown 743162013d sched: Remove proliferation of wait_on_bit() action functions
The current "wait_on_bit" interface requires an 'action'
function to be provided which does the actual waiting.
There are over 20 such functions, many of them identical.
Most cases can be satisfied by one of just two functions, one
which uses io_schedule() and one which just uses schedule().

So:
 Rename wait_on_bit and        wait_on_bit_lock to
        wait_on_bit_action and wait_on_bit_lock_action
 to make it explicit that they need an action function.

 Introduce new wait_on_bit{,_lock} and wait_on_bit{,_lock}_io
 which are *not* given an action function but implicitly use
 a standard one.
 The decision to error-out if a signal is pending is now made
 based on the 'mode' argument rather than being encoded in the action
 function.

 All instances of the old wait_on_bit and wait_on_bit_lock which
 can use the new version have been changed accordingly and their
 action functions have been discarded.
 wait_on_bit{_lock} does not return any specific error code in the
 event of a signal so the caller must check for non-zero and
 interpolate their own error code as appropriate.

The wait_on_bit() call in __fscache_wait_on_invalidate() was
ambiguous as it specified TASK_UNINTERRUPTIBLE but used
fscache_wait_bit_interruptible as an action function.
David Howells confirms this should be uniformly
"uninterruptible"

The main remaining user of wait_on_bit{,_lock}_action is NFS
which needs to use a freezer-aware schedule() call.

A comment in fs/gfs2/glock.c notes that having multiple 'action'
functions is useful as they display differently in the 'wchan'
field of 'ps'. (and /proc/$PID/wchan).
As the new bit_wait{,_io} functions are tagged "__sched", they
will not show up at all, but something higher in the stack.  So
the distinction will still be visible, only with different
function names (gds2_glock_wait versus gfs2_glock_dq_wait in the
gfs2/glock.c case).

Since first version of this patch (against 3.15) two new action
functions appeared, on in NFS and one in CIFS.  CIFS also now
uses an action function that makes the same freezer aware
schedule call as NFS.

Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: David Howells <dhowells@redhat.com> (fscache, keys)
Acked-by: Steven Whitehouse <swhiteho@redhat.com> (gfs2)
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steve French <sfrench@samba.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140707051603.28027.72349.stgit@notabene.brown
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-07-16 15:10:39 +02:00
Peter Zijlstra 4e857c58ef arch: Mass conversion of smp_mb__*()
Mostly scripted conversion of the smp_mb__* barriers.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-55dhyhocezdw1dg7u19hmh1u@git.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-arch@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-04-18 14:20:48 +02:00
Bob Peterson 01b172b7b1 GFS2: Ensure workqueue is scheduled after noexp request
This patch closes a small timing window whereby a request to hold the
transaction glock can get stuck. The problem is that after the DLM has
granted the lock, it can get into a state whereby it doesn't transition
the glock to a held state, due to not having requeued the glock state
machine to finish the transition.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2014-03-12 14:45:48 +00:00
Joe Perches d77d1b58aa GFS2: Use pr_<level> more consistently
Add pr_fmt, remove embedded "GFS2: " prefixes.
This now consistently emits lower case "gfs2: " for each message.

Other miscellanea around these changes:

o Add missing newlines
o Coalesce formats
o Realign arguments

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2014-03-07 09:30:51 +00:00
Fabian Frederick fc554ed3d8 GFS2: global conversion to pr_foo()
-All printk(KERN_foo converted to pr_foo().
-Messages updated to fit in 80 columns.
-fs_macros converted as well.
-fs_printk removed.

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2014-03-06 17:34:06 +00:00
Steven Whitehouse ac3beb6a5d GFS2: Don't use ENOBUFS when ENOMEM is the correct error code
Al Viro has tactfully pointed out that we are using the incorrect
error code in some cases. This patch fixes that, and also removes
the (unused) return value for glock dumping.

>        * gfs2_iget() - ENOBUFS instead of ENOMEM.  ENOBUFS is
> "No buffer space available (POSIX.1 (XSI STREAMS option))" and since
> we don't support STREAMS it's probably fair game, but... what the hell?

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
2014-01-16 10:31:13 +00:00
Tetsuo Handa 0b3a2c9968 GFS2: Fix unsafe dereference in dump_holder()
GLOCK_BUG_ON() might call this function without RCU read lock. Make sure that
RCU read lock is held when using task_struct returned from pid_task().

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2014-01-02 12:18:04 +00:00
Michal Nazarewicz e3c4269d13 GFS2: fix potential NULL pointer dereference
Commit [e66cf1610: GFS2: Use lockref for glocks] replaced call:
    atomic_read(&gi->gl->gl_ref) == 0
with:
    __lockref_is_dead(&gl->gl_lockref)
therefore changing how gl is accessed, from gi->gl to plan gl.
However, gl can be a NULL pointer, and so gi->gl needs to be
used instead (which is guaranteed not to be NULL because fo
the while loop checking that condition).

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-11-21 09:55:45 +00:00
Steven Whitehouse e66cf16109 GFS2: Use lockref for glocks
Currently glocks have an atomic reference count and also a spinlock
which covers various internal fields, such as the state. This intent of
this patch is to replace the spinlock and the atomic reference count
with a lockref structure. This contains a spinlock which we can continue
to use as before, and a reference counter which is used in conjuction
with the spinlock to replace the previous atomic counter.

As a result of this there are some new rules for reference counting on
glocks. We need to distinguish between reference count changes under
gl_spin (which are now just increment or decrement of the new counter,
provided the count cannot hit zero) and those which are outside of
gl_spin, but which now take gl_spin internally.

The conversion is relatively straight forward. There is probably some
further clean up which can be done, but the priority at this stage is to
make the change in as simple a manner as possible.

A consequence of this change is that the reference count is being
decoupled from the lru list processing. This should allow future
adoption of the lru_list code with glocks in due course.

The reason for using the "dead" state and not just relying on 0 being
the "invalid state" is so that in due course 0 ref counts can be
allowable. The intent is to eventually be able to remove the ref count
changes which are currently hidden away in state_change().

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-10-15 15:18:08 +01:00
Dave Chinner 1ab6c4997e fs: convert fs shrinkers to new scan/count API
Convert the filesystem shrinkers to use the new API, and standardise some
of the behaviours of the shrinkers at the same time.  For example,
nr_to_scan means the number of objects to scan, not the number of objects
to free.

I refactored the CIFS idmap shrinker a little - it really needs to be
broken up into a shrinker per tree and keep an item count with the tree
root so that we don't need to walk the tree every time the shrinker needs
to count the number of objects in the tree (i.e.  all the time under
memory pressure).

[glommer@openvz.org: fixes for ext4, ubifs, nfs, cifs and glock. Fixes are needed mainly due to new code merged in the tree]
[assorted fixes folded in]
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Glauber Costa <glommer@openvz.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Carlos Maiolino <cmaiolino@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Rientjes <rientjes@google.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: J. Bruce Fields <bfields@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-09-10 18:56:31 -04:00
Glauber Costa 55f841ce93 super: fix calculation of shrinkable objects for small numbers
The sysctl knob sysctl_vfs_cache_pressure is used to determine which
percentage of the shrinkable objects in our cache we should actively try
to shrink.

It works great in situations in which we have many objects (at least more
than 100), because the aproximation errors will be negligible.  But if
this is not the case, specially when total_objects < 100, we may end up
concluding that we have no objects at all (total / 100 = 0, if total <
100).

This is certainly not the biggest killer in the world, but may matter in
very low kernel memory situations.

Signed-off-by: Glauber Costa <glommer@openvz.org>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Carlos Maiolino <cmaiolino@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Rientjes <rientjes@google.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: J. Bruce Fields <bfields@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-09-10 18:56:29 -04:00
Bob Peterson 068213f7d3 GFS2: Remove unnecessary memory barrier
Function test_and_clear_bit implies a memory barrier, so subsequent
memory barriers are unnecessary.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-09-04 15:58:21 +01:00
Steven Whitehouse 7286b31eab GFS2: Take glock reference in examine_bucket()
We need to check the glock ref counter in a race free way
in order to ensure that the gfs2_glock_hold() call will
succeed. The easiest way to do that is to simply take the
reference count early in the common code of examine_bucket,
skipping any glocks with zero ref count.

That means that the examiner functions all need to put their
reference on the glock once they've performed their function.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Reported-by: David Teigland <teigland@redhat.com>
Tested-by: David Teigland <teigland@redhat.com>
2013-08-20 09:35:09 +01:00
Dan Carpenter dfc4616dde GFS2: alloc_workqueue() doesn't return an ERR_PTR
alloc_workqueue() returns a NULL on error, it doesn't return an ERR_PTR.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-08-19 09:33:43 +01:00
Linus Torvalds e72859b87f Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-nmw
Pull GFS2 updates from Steven Whitehouse:
 "There is not a whole lot of change this time - there are some further
  changes which are in the works, but those will be held over until next
  time.

  Here there are some clean ups to inode creation, the addition of an
  origin (local or remote) indicator to glock demote requests, removal
  of one of the remaining GFP_NOFAIL allocations during log flushes, one
  minor clean up, and a one liner bug fix."

* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-nmw:
  GFS2: Flush work queue before clearing glock hash tables
  GFS2: Add origin indicator to glock demote tracing
  GFS2: Add origin indicator to glock callbacks
  GFS2: replace gfs2_ail structure with gfs2_trans
  GFS2: Remove vestigial parameter ip from function rs_deltree
  GFS2: Use gfs2_dinode_out() in the inode create path
  GFS2: Remove gfs2_refresh_inode from inode creation path
  GFS2: Clean up inode creation path
2013-04-30 11:27:14 -07:00
Joe Perches 7af584d3b0 gfs2: Convert print_symbol to %pSR
Use the new vsprintf extension to avoid any possible
message interleaving.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2013-04-29 15:23:20 +02:00
Bob Peterson 222cb538f5 GFS2: Flush work queue before clearing glock hash tables
There was a timing window when a GFS2 file system was unmounted
that caused GFS2 to call BUG() and panic the kernel. The call
to BUG() is meant to ensure that the glock reference count,
gl_ref, never gets down to zero and bounce back up again. What was
happening during umount is that function gfs2_put_super was dequeing
its glocks for well-known files. In particular, we saw it on the
journal glock, sd_jinode_gh. The dequeue caused delayed work to be
queued for the glock state machine, to transition the lock to an
"unlocked" state. While the work was still queued, gfs2_put_super
called gfs2_gl_hash_clear to clear out the glock hash tables.
If the timing was just so, the glock work function would drop the
reference count at the time when it was being checked for zero,
and that caused BUG() to be called. This patch calls
flush_workqueue before clearing the glock hash tables, thereby
ensuring that the delayed work is executed before the hash tables
are cleared, and therefore the reference count never goes to zero
until the glock is cleared.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-04-26 10:09:04 +01:00
Steven Whitehouse 7bd8b2eb32 GFS2: Add origin indicator to glock demote tracing
This adds the origin indicator to the trace point for glock
demotion, so that it is possible to see where demote requests
have come from.

Note that requests generated from the demote_rq sysfs interface
will show as remote, since they are intended to replicate
exactly the effect of a demote reuqest from a remote node. It
is still possible to tell these apart by looking at the process
which initiated the demote request.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-04-10 10:32:05 +01:00
Steven Whitehouse 81ffbf654f GFS2: Add origin indicator to glock callbacks
This patch adds a bool indicating whether the demote
request was originated locally or remotely. This is then
used by the iopen ->go_callback() to make 100% sure that
it will only respond to remote callbacks.

Since ->evict_inode() uses GL_NOCACHE when it attempts to
get an exclusive lock on the iopen lock, this may result
in extra scheduling of the workqueue in case that the
exclusive promotion request failed. This patch prevents
that from happening.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-04-10 10:26:55 +01:00
Steven Whitehouse 28fb302755 GFS2: Remove gfs2_refresh_inode from inode creation path
The original method for creating inodes used in GFS2 was to fill
out a buffer, with all the information, and then to read that
buffer into the in-core inode, using gfs2_refresh_inode()

The problem with this approach is that all the inode's fields
need to be calculated ahead of time, and were stored in various
variables making the code rather complicated.

The new approach is simply to allocate the in-core inode earlier
and fill in as many fields as possible ahead of time. These can
then be used to initilise the on disk representation. The
code has been working towards the point where it is possible
to remove gfs2_refresh_inode() because all the fields are
correctly initialised ahead of time. We've now reached that
milestone, and have reversed the order of setting up the in
core and on disk inodes.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-04-08 08:40:17 +01:00
Steven Whitehouse 4506a519f2 GFS2: Split glock lru processing into two parts
The intent here is to split the processing of the glock lru
list into two parts, so that the selection of glocks and the
disposal are separate functions. The plan is then, that further
updates can then be made to these functions in the future
to improve the selection of glocks and also the efficiency of
glock disposal.

The new feature which this patch brings is sorting the
glocks to be disposed of into glock number (and thus also
disk block number) order. Not all glocks will need i/o in
order to dispose of them, but some will, and at least we'll
generate mostly disk block order i/o now.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-02-01 20:36:03 +00:00
Steven Whitehouse 2a00585593 GFS2: Separate LRU scanning from shrinker
This breaks out the LRU scanning function from the shrinker in
preparation for adding other callers to the LRU scanner.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-01-29 10:27:28 +00:00
Linus Torvalds 08242bc221 Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-nmw
Pull GFS2 updates from Steven Whitehouse:
 "The main feature this time is the new Orlov allocator and the patches
  leading up to it which allow us to allocate new inodes from their own
  allocation context, rather than borrowing that of their parent
  directory.  It is this change which then allows us to choose a
  different location for subdirectories when required.  This works
  exactly as per the ext3 implementation from the users point of view.

  In addition to that, we've got a speed up in gfs2_rbm_from_block()
  from Bob Peterson, three locking related improvements from Dave
  Teigland plus a selection of smaller bug fixes and clean ups."

* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-nmw:
  GFS2: Set gl_object during inode create
  GFS2: add error check while allocating new inodes
  GFS2: don't reference inode's glock during block allocation trace
  GFS2: remove redundant lvb pointer
  GFS2: only use lvb on glocks that need it
  GFS2: skip dlm_unlock calls in unmount
  GFS2: Fix one RG corner case
  GFS2: Eliminate redundant buffer_head manipulation in gfs2_unlink_inode
  GFS2: Use dirty_inode in gfs2_dir_add
  GFS2: Fix truncation of journaled data files
  GFS2: Add Orlov allocator
  GFS2: Use proper allocation context for new inodes
  GFS2: Add test for resource group congestion status
  GFS2: Rename glops go_xmote_th to go_sync
  GFS2: Speed up gfs2_rbm_from_block
  GFS2: Review bug traps in glops.c
2012-12-15 12:34:21 -08:00
Rafael Aquini 252aa6f5be mm: redefine address_space.assoc_mapping
Overhaul struct address_space.assoc_mapping renaming it to
address_space.private_data and its type is redefined to void*.  By this
approach we consistently name the .private_* elements from struct
address_space as well as allow extended usage for address_space
association with other data structures through ->private_data.

Also, all users of old ->assoc_mapping element are converted to reflect
its new name and type change (->private_data).

Signed-off-by: Rafael Aquini <aquini@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-11 17:22:26 -08:00
David Teigland 4e2f8849de GFS2: remove redundant lvb pointer
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>
2012-11-15 10:17:22 +00:00
David Teigland dba2d70c5d GFS2: only use lvb on glocks that need it
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>
2012-11-15 10:16:59 +00:00