gfs2: Remove 'first' trace_gfs2_promote argument

Remove the 'first' argument of trace_gfs2_promote: with GL_SKIP, the
'first' holder isn't the one that instantiates the glock
(gl_instantiate), which

gfs2: Remove 'first' trace_gfs2_promote argument

Remove the 'first' argument of trace_gfs2_promote: with GL_SKIP, the
'first' holder isn't the one that instantiates the glock
(gl_instantiate), which is what the 'first' flag was apparently supposed
to indicate.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

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gfs2: Add per-reservation reserved block accounting

Add a rs_reserved field to struct gfs2_blkreserv to keep track of the number of
blocks reserved by this particular reservation, and a rd_reserved

gfs2: Add per-reservation reserved block accounting

Add a rs_reserved field to struct gfs2_blkreserv to keep track of the number of
blocks reserved by this particular reservation, and a rd_reserved field to
struct gfs2_rgrpd to keep track of the total number of reserved blocks in the
resource group. Those blocks are exclusively reserved, as opposed to the
rs_requested / rd_requested blocks which are tracked in the reservation tree
(rd_rstree) and which can be stolen if necessary.

When making a reservation with gfs2_inplace_reserve, rs_reserved is set to
somewhere between ap->min_target and ap->target depending on the number of free
blocks in the resource group. When allocating blocks with gfs2_alloc_blocks,
rs_reserved is decremented accordingly. Eventually, any reserved but not
consumed blocks are returned to the resource group by gfs2_inplace_release.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

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gfs2: Rename rs_{free -> requested} and rd_{reserved -> requested}

We keep track of what we've so far been referring to as reservations in
rd_rstree: the nodes in that tree indicate where in a resou

gfs2: Rename rs_{free -> requested} and rd_{reserved -> requested}

We keep track of what we've so far been referring to as reservations in
rd_rstree: the nodes in that tree indicate where in a resource group we'd
like to allocate the next couple of blocks for a particular inode. Local
processes take those as hints, but they may still "steal" blocks from those
extents, so when actually allocating a block, we must double check in the
bitmap whether that block is actually still free. Likewise, other cluster
nodes may "steal" such blocks as well.

One of the following patches introduces resource group glock sharing, i.e.,
sharing of an exclusively locked resource group glock among local processes to
speed up allocations. To make that work, we'll need to keep track of how many
blocks we've actually reserved for each inode, so we end up with two different
kinds of reservations.

Distinguish these two kinds by referring to blocks which are reserved but may
still be "stolen" as "requested". This rename also makes it more obvious that
rs_requested and rd_requested are strongly related.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

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gfs2: Only use struct gfs2_rbm for bitmap manipulations

GFS2 uses struct gfs2_rbm to represent a filesystem block number as a
bit position within a resource group. This representation is used in
th

gfs2: Only use struct gfs2_rbm for bitmap manipulations

GFS2 uses struct gfs2_rbm to represent a filesystem block number as a
bit position within a resource group. This representation is used in
the bitmap manipulation code to prevent excessive conversions between
block numbers and bit positions, but also in struct gfs2_blkreserv which
is part of struct gfs2_inode, to mark the start of a reservation. In
the inode, the bit position representation makes less sense: first, the
start position is used as a block number about as often as a bit
position; second, the bit position representation makes the code
unnecessarily complicated and difficult to read.

Therefore, change struct gfs2_blkreserv to represent the start of a
reservation as a block number instead of a bit position. (This requires
keeping track of the resource group in gfs2_blkreserv separately.) With
that change, various things can be slightly simplified, and struct
gfs2_rbm can be moved to rgrp.c.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

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gfs2: eliminate GLF_QUEUED flag in favor of list_empty(gl_holders)

Before this patch, glock.c maintained a flag, GLF_QUEUED, which indicated
when a glock had a holder queued. It was only checked for

gfs2: eliminate GLF_QUEUED flag in favor of list_empty(gl_holders)

Before this patch, glock.c maintained a flag, GLF_QUEUED, which indicated
when a glock had a holder queued. It was only checked for inode glocks,
although set and cleared by all glocks, and it was only used to determine
whether the glock should be held for the minimum hold time before releasing.

The problem is that the flag is not accurate at all. If a process holds
the glock, the flag is set. When they dequeue the glock, it only cleared
the flag in cases when the state actually changed. So if the state doesn't
change, the flag may still be set, even when nothing is queued.

This happens to iopen glocks often: the get held in SH, then the file is
closed, but the glock remains in SH mode.

We don't need a special flag to indicate this: we can simply tell whether
the glock has any items queued to the holders queue. It's a waste of cpu
time to maintain it.

This patch eliminates the flag in favor of simply checking list_empty
on the glock holders.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

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gfs2: enhance log_blocks trace point to show log blocks free

This patch adds some code to enhance the log_blocks trace point. It
reports the number of free log blocks. This makes the trace point muc

gfs2: enhance log_blocks trace point to show log blocks free

This patch adds some code to enhance the log_blocks trace point. It
reports the number of free log blocks. This makes the trace point much
more useful, especially for debugging performance problems when we can
tell when the journal gets full and needs to wait for flushes, etc.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

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gfs2: eliminate rs_inum and reduce the size of gfs2 inodes

Before this patch, block reservations kept track of the inode
number. At one point, that was a valid thing to do. However, since
we made th

gfs2: eliminate rs_inum and reduce the size of gfs2 inodes

Before this patch, block reservations kept track of the inode
number. At one point, that was a valid thing to do. However, since
we made the reservation a part of the inode (rather than a pointer
to a separate allocated object) the reservation can determine the
inode number by using container_of. This saves us a little memory
in our inode.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>

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gfs2: gfs2_iomap_end tracepoint: log block address

In the gfs2_iomap_end tracepoint, log the physical block address, just
as in the gfs2_bmap tracepoint.

Signed-off-by: Andreas Gruenbacher <agruenb

gfs2: gfs2_iomap_end tracepoint: log block address

In the gfs2_iomap_end tracepoint, log the physical block address, just
as in the gfs2_bmap tracepoint.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>

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GFS2: Log the reason for log flushes in every log header

This patch just adds the capability for GFS2 to track which function
called gfs2_log_flush. This should make it easier to diagnose
problems b

GFS2: Log the reason for log flushes in every log header

This patch just adds the capability for GFS2 to track which function
called gfs2_log_flush. This should make it easier to diagnose
problems based on the sequence of events found in the journals.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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GFS2: Implement iomap for block_map

This patch implements iomap for block mapping, and switches the
block_map function to use it under the covers.

The additional IOMAP_F_BOUNDARY iomap flag indicat

GFS2: Implement iomap for block_map

This patch implements iomap for block mapping, and switches the
block_map function to use it under the covers.

The additional IOMAP_F_BOUNDARY iomap flag indicates when iomap has
reached a "metadata boundary" and fetching the next mapping is likely to
incur an additional I/O. This flag is used for setting the bh buffer
boundary flag.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

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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
implementati

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: 0166b197c2ed ("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>

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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 fie

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>

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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 tha

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>

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GFS2: don't reference inode's glock during block allocation trace

This patch changes the block allocation trace so that it references
the rgd's glock rather than the inode's glock. Now that the orde

GFS2: don't reference inode's glock during block allocation trace

This patch changes the block allocation trace so that it references
the rgd's glock rather than the inode's glock. Now that the order
of inode creation is switched, this prevents a reference to the
glock which may not be set yet.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

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GFS2: Improve block reservation tracing

This patch improves the tracing of block reservations by
removing some corner cases and also providing more useful
detail in the traces.

A new field is added

GFS2: Improve block reservation tracing

This patch improves the tracing of block reservations by
removing some corner cases and also providing more useful
detail in the traces.

A new field is added to the reservation structure to contain
the inode number. This is used since in certain contexts it is
not possible to access the inode itself to obtain this information.
As a result we can then display the inode number for all tracepoints
and also in case we dump the resource group.

The "del" tracepoint operation has been removed. This could be called
with the reservation rgrp set to NULL. That resulted in not printing
the device number, and thus making the information largely useless
anyway. Also, the conditional on the rgrp being NULL can then be
removed from the tracepoint. After this change, all the block
reservation tracepoint calls will be called with the rgrp information.

The existing ins,clm and tdel calls to the block reservation tracepoint
are sufficient to track the entire life of the block reservation.

In gfs2_block_alloc() the error detection is updated to print out
the inode number of the problematic inode. This can then be compared
against the information in the glock dump,tracepoints, etc.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

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GFS2: Add structure to contain rgrp, bitmap, offset tuple

This patch introduces a new structure, gfs2_rbm, which is a
tuple of a resource group, a bitmap within the resource group
and an offset with

GFS2: Add structure to contain rgrp, bitmap, offset tuple

This patch introduces a new structure, gfs2_rbm, which is a
tuple of a resource group, a bitmap within the resource group
and an offset within that bitmap. This is designed to make
manipulating these sets of variables easier. There is also a
new helper function which converts this representation back
to a disk block address.

In addition, the rbtree nodes which are used for the reservations
were not being correctly initialised, which is now fixed. Also,
the tracing was not passing through the inode where it should
have been. That is mostly fixed aside from one corner case. This
needs to be revisited since there can also be a NULL rgrp in
some cases which results in the device being incorrect in the
trace.

This is intended to be the first step towards cleaning up some
of the allocation code, and some further bug fixes.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

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GFS2: Reduce file fragmentation

This patch reduces GFS2 file fragmentation by pre-reserving blocks. The
resulting improved on disk layout greatly speeds up operations in cases
which would have resul

GFS2: Reduce file fragmentation

This patch reduces GFS2 file fragmentation by pre-reserving blocks. The
resulting improved on disk layout greatly speeds up operations in cases
which would have resulted in interlaced allocation of blocks previously.
A typical example of this is 10 parallel dd processes, each writing to a
file in a common dirctory.

The implementation uses an rbtree of reservations attached to each
resource group (and each inode).

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

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GFS2: Add rgrp information to block_alloc trace point

This is a second attempt at a patch that adds rgrp information to the
block allocation trace point for GFS2. As suggested, the patch was
modifie

GFS2: Add rgrp information to block_alloc trace point

This is a second attempt at a patch that adds rgrp information to the
block allocation trace point for GFS2. As suggested, the patch was
modified to list the rgrp information _after_ the fields that exist today.

Again, the reason for this patch is to allow us to trace and debug
problems with the block reservations patch, which is still in the works.
We can debug problems with reservations if we can see what block allocations
result from the block reservations. It may also be handy in figuring out
if there are problems in rgrp free space accounting. In other words,
we can use it to track the rgrp and its free space along side the allocations
that are taking place.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

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GFS2: glock statistics gathering

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 i

GFS2: glock statistics gathering

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>

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GFS2: Add an AIL writeback tracepoint

Add a tracepoint for monitoring writeback of the AIL.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

GFS2: Improve tracing support (adds two flags)

This adds support for two new flags. One keeps track of whether
the glock is on the LRU list or not. The other isn't really a
flag as such, but an indi

GFS2: Improve tracing support (adds two flags)

This adds support for two new flags. One keeps track of whether
the glock is on the LRU list or not. The other isn't really a
flag as such, but an indication of whether the glock has an
attached object or not. This indication is reported without
any locking, which is ok since we do not dereference the object
pointer but merely report whether it is NULL or not.

Also, this fixes one place where a tracepoint was missing, which
was at the point we remove deallocated blocks from the journal.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

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

Due to the design of the VFS, it is quite usual for operations on GFS2
to consist of a lookup (requiring a shared lock) f

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

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 <swhiteho@redhat.com>
Tested-by: Abhijith Das <adas@redhat.com>

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tracing/events: Move TRACE_SYSTEM outside of include guard

If TRACE_INCLDUE_FILE is defined, <trace/events/TRACE_INCLUDE_FILE.h>
will be included and compiled, otherwise it will be
<trace/events/TRA

tracing/events: Move TRACE_SYSTEM outside of include guard

If TRACE_INCLDUE_FILE is defined, <trace/events/TRACE_INCLUDE_FILE.h>
will be included and compiled, otherwise it will be
<trace/events/TRACE_SYSTEM.h>

So TRACE_SYSTEM should be defined outside of #if proctection,
just like TRACE_INCLUDE_FILE.

Imaging this scenario:

#include <trace/events/foo.h>
-> TRACE_SYSTEM == foo
...
#include <trace/events/bar.h>
-> TRACE_SYSTEM == bar
...
#define CREATE_TRACE_POINTS
#include <trace/events/foo.h>
-> TRACE_SYSTEM == bar !!!

and then bar.h will be included and compiled.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A5A9CF1.2010007@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

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GFS2: Add tracepoints

This patch adds the ability to trace various aspects of the GFS2
filesystem. The trace points are divided into three groups,
glocks, logging and bmap. These points have been ch

GFS2: Add tracepoints

This patch adds the ability to trace various aspects of the GFS2
filesystem. The trace points are divided into three groups,
glocks, logging and bmap. These points have been chosen because
they allow inspection of the major internal functions of GFS2
and they are also generic enough that they are unlikely to need
any major changes as the filesystem evolves.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

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