GFS2: Remove bd_list_tr

This is another clean up in the logging code. This per-transaction
list was largely unused. Its main function was to ensure that the
number of buffers in a transaction was co

GFS2: Remove bd_list_tr

This is another clean up in the logging code. This per-transaction
list was largely unused. Its main function was to ensure that the
number of buffers in a transaction was correct, however that counter
was only used to check the number of buffers in the bd_list_tr, plus
an assert at the end of each transaction. With the assert now changed
to use the calculated buffer counts, we can remove both bd_list_tr and
its associated counter.

This should make the code easier to understand as well as shrinking
a couple of structures.

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

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GFS2: Clean up log write code path

Prior to this patch, we have two ways of sending i/o to the log.
One of those is used when we need to allocate both the data
to be written itself and also a buffer

GFS2: Clean up log write code path

Prior to this patch, we have two ways of sending i/o to the log.
One of those is used when we need to allocate both the data
to be written itself and also a buffer head to submit it. This
is done via sb_getblk and friends. This is used mostly for writing
log headers.

The other method is used when writing blocks which have some
in-place counterpart. This is the case for all the metadata
blocks which are journalled, and when journaled data is in use,
for unescaped journalled data blocks.

This patch replaces both of those two methods, and about half
a dozen separate i/o submission points with a single i/o
submission function. We also go direct to bio rather than
using buffer heads, since this allows us to build i/o
requests of the maximum size for the block device in
question. It also reduces the memory required for flushing
the log, which can be very useful in low memory situations.

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

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GFS2: Drop "pull" argument from log_write_header()

The "pull" argument to log_write_header() is only used
for debug purposes and it is not really needed any more. There
are other tests for this part

GFS2: Drop "pull" argument from log_write_header()

The "pull" argument to log_write_header() is only used
for debug purposes and it is not really needed any more. There
are other tests for this particular problem, so I think we can
dispose of it in order to simplify the code.

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

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GFS2: Clean up log flush header writing

We already send both a pre and post flush to the block device
when writing a journal header. There is no need to wait for
the previous I/O specifically when w

GFS2: Clean up log flush header writing

We already send both a pre and post flush to the block device
when writing a journal header. There is no need to wait for
the previous I/O specifically when we do this, unless we've
turned "barriers" off.

As a side effect, this also cleans up the code path for flushing
the journal and makes it more readable.

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

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GFS2: Make bd_cmp() static

Add missing static to bd_cmp()

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

GFS2: Sort the ordered write list

This patch sorts the ordered write list for GFS2 writes.
This increases the throughput for simultaneous writes.
For example, if you have ten processes, all doing:
d

GFS2: Sort the ordered write list

This patch sorts the ordered write list for GFS2 writes.
This increases the throughput for simultaneous writes.
For example, if you have ten processes, all doing:
dd if=/dev/zero of=/mnt/gfs2/fileX
on different files, the throughput will be much better.

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

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GFS2: Move two functions from log.c to lops.c

gfs2_log_get_buf() and gfs2_log_fake_buf() are both used
only in lops.c, so move them next to their callers and they
can then become static.

Signed-off

GFS2: Move two functions from log.c to lops.c

gfs2_log_get_buf() and gfs2_log_fake_buf() are both used
only in lops.c, so move them next to their callers and they
can then become static.

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

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freezer: unexport refrigerator() and update try_to_freeze() slightly

There is no reason to export two functions for entering the
refrigerator. Calling refrigerator() instead of try_to_freeze()
does

freezer: unexport refrigerator() and update try_to_freeze() slightly

There is no reason to export two functions for entering the
refrigerator. Calling refrigerator() instead of try_to_freeze()
doesn't save anything noticeable or removes any race condition.

* Rename refrigerator() to __refrigerator() and make it return bool
indicating whether it scheduled out for freezing.

* Update try_to_freeze() to return bool and relay the return value of
__refrigerator() if freezing().

* Convert all refrigerator() users to try_to_freeze().

* Update documentation accordingly.

* While at it, add might_sleep() to try_to_freeze().

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Samuel Ortiz <samuel@sortiz.org>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: Christoph Hellwig <hch@infradead.org>

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GFS2: Fix up REQ flags

Christoph has split up REQ_PRIO from REQ_META. That means that
we can drop REQ_PRIO from places where is it not needed. I'm
not at all sure that the combination WRITE_FLUSH_FU

GFS2: Fix up REQ flags

Christoph has split up REQ_PRIO from REQ_META. That means that
we can drop REQ_PRIO from places where is it not needed. I'm
not at all sure that the combination WRITE_FLUSH_FUA | REQ_PRIO
makes any kind of sense, anyway.

In addition, I've added REQ_META to one place in the code where
it was missing. REQ_PRIO has been left for read/writes triggered
by glock acquisition and writeback only. We can adjust it again
if required, but these are the most important points from a
performance perspective.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>

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block: separate priority boosting from REQ_META

Add a new REQ_PRIO to let requests preempt others in the cfq I/O schedule,
and lave REQ_META purely for marking requests as metadata in blktrace.

All

block: separate priority boosting from REQ_META

Add a new REQ_PRIO to let requests preempt others in the cfq I/O schedule,
and lave REQ_META purely for marking requests as metadata in blktrace.

All existing callers of REQ_META except for XFS are updated to also
set REQ_PRIO for now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

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GFS2: Resolve inode eviction and ail list interaction bug

This patch contains a few misc fixes which resolve a recently
reported issue. This patch has been a real team effort and has
received a lot

GFS2: Resolve inode eviction and ail list interaction bug

This patch contains a few misc fixes which resolve a recently
reported issue. This patch has been a real team effort and has
received a lot of testing.

The first issue is that the ail lock needs to be held over a few
more operations. The lock thats added into gfs2_releasepage() may
possibly be a candidate for replacing with RCU at some future
point, but at this stage we've gone for the obvious fix.

The second issue is that gfs2_write_inode() can end up calling
a glock recursively when called from gfs2_evict_inode() via the
syncing code, so it needs a guard added.

The third issue is that we either need to not truncate the metadata
pages of inodes which have zero link count, but which we cannot
deallocate due to them still being in use by other nodes, or we need
to ensure that those pages have all made it through the journal and
ail lists first. This patch takes the former approach, but the
latter has also been tested and there is nothing to choose between
them performance-wise. So again, we could revise that decision
in the future.

Also, the inode eviction process is now better documented.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Tested-by: Bob Peterson <rpeterso@redhat.com>
Tested-by: Abhijith Das <adas@redhat.com>
Reported-by: Barry J. Marson <bmarson@redhat.com>
Reported-by: David Teigland <teigland@redhat.com>

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GFS2: Wait properly when flushing the ail list

The ail flush code has always relied upon log flushing to prevent
it from spinning needlessly. This fixes it to wait on the last
I/O request submitted

GFS2: Wait properly when flushing the ail list

The ail flush code has always relied upon log flushing to prevent
it from spinning needlessly. This fixes it to wait on the last
I/O request submitted (we don't need to wait for all of it)
instead of either spinning with io_schedule or sleeping.

As a result cpu usage of gfs2_logd is much reduced with certain
workloads.

Reported-by: Abhijith Das <adas@redhat.com>
Tested-by: Abhijith Das <adas@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

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GFS2: Fix ail list traversal

In the recent patches to update the AIL list code, I managed to
forget that the ail list lock got dropped, even though I
added a comment specifically to remind myself :(

GFS2: Fix ail list traversal

In the recent patches to update the AIL list code, I managed to
forget that the ail list lock got dropped, even though I
added a comment specifically to remind myself :(

Reported-by: Barry Marson <bmarson@redhat.com>
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: Make writeback more responsive to system conditions

This patch adds writeback_control to writing back the AIL
list. This means that we can then take advantage of the
information we get in ->wr

GFS2: Make writeback more responsive to system conditions

This patch adds writeback_control to writing back the AIL
list. This means that we can then take advantage of the
information we get in ->write_inode() in order to set off
some pre-emptive writeback.

In addition, the AIL code is cleaned up a bit to make it
a bit simpler to understand.

There is still more which can usefully be done in this area,
but this is a good start at least.

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

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GFS2: Use filemap_fdatawrite() to write back the AIL

In order to ensure that the mapping stats (and thus the bdi) are correctly
updated, this patch changes the AIL writeback to use the filemap_dataw

GFS2: Use filemap_fdatawrite() to write back the AIL

In order to ensure that the mapping stats (and thus the bdi) are correctly
updated, this patch changes the AIL writeback to use the filemap_datawrite
function. This helps prevent stalls in balance_dirty_pages() due to
large amounts of dirty metadata when there is little or no dirty data
around.

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

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GFS2: Update to AIL list locking

The previous patch missed a couple of places where the AIL list
needed locking, so this fixes up those places, plus a comment
is corrected too.

Signed-off-by: Steve

GFS2: Update to AIL list locking

The previous patch missed a couple of places where the AIL list
needed locking, so this fixes up those places, plus a comment
is corrected too.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Dave Chinner <dchinner@redhat.com>

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GFS2: introduce AIL lock

The log lock is currently used to protect the AIL lists and
the movements of buffers into and out of them. The lists
are self contained and no log specific items outside the

GFS2: introduce AIL lock

The log lock is currently used to protect the AIL lists and
the movements of buffers into and out of them. The lists
are self contained and no log specific items outside the
lists are accessed when starting or emptying the AIL lists.

Hence the operation of the AIL does not require the protection
of the log lock so split them out into a new AIL specific lock
to reduce the amount of traffic on the log lock. This will
also reduce the amount of serialisation that occurs when
the gfs2_logd pushes on the AIL to move it forward.

This reduces the impact of log pushing on sequential write
throughput.

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

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block: kill off REQ_UNPLUG

With the plugging now being explicitly controlled by the
submitter, callers need not pass down unplugging hints
to the block layer. If they want to unplug, it's because th

block: kill off REQ_UNPLUG

With the plugging now being explicitly controlled by the
submitter, callers need not pass down unplugging hints
to the block layer. If they want to unplug, it's because they
manually plugged on their own - in which case, they should just
unplug at will.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

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GFS2: gfs2_logd should be using interruptible waits

Looks like this crept in, in a recent update.

Reported-by: Krzysztof Urbaniak <urban@bash.org.pl>
Signed-off-by: Steven Whitehouse <swhiteho@red

GFS2: gfs2_logd should be using interruptible waits

Looks like this crept in, in a recent update.

Reported-by: Krzysztof Urbaniak <urban@bash.org.pl>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

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gfs2: replace barriers with explicit flush / FUA usage

Switch to the WRITE_FLUSH_FUA flag for log writes, remove the EOPNOTSUPP
detection for barriers and stop setting the barrier flag for discards.

gfs2: replace barriers with explicit flush / FUA usage

Switch to the WRITE_FLUSH_FUA flag for log writes, remove the EOPNOTSUPP
detection for barriers and stop setting the barrier flag for discards.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Acked-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

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block: unify flags for struct bio and struct request

Remove the current bio flags and reuse the request flags for the bio, too.
This allows to more easily trace the type of I/O from the filesystem
d

block: unify flags for struct bio and struct request

Remove the current bio flags and reuse the request flags for the bio, too.
This allows to more easily trace the type of I/O from the filesystem
down to the block driver. There were two flags in the bio that were
missing in the requests: BIO_RW_UNPLUG and BIO_RW_AHEAD. Also I've
renamed two request flags that had a superflous RW in them.

Note that the flags are in bio.h despite having the REQ_ name - as
blkdev.h includes bio.h that is the only way to go for now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

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block: BARRIER request should imply SYNC

A barrier request should by defintion have priority in get_request
and let the queue be unplugged immediately as it's blocking all forward
progress due to th

block: BARRIER request should imply SYNC

A barrier request should by defintion have priority in get_request
and let the queue be unplugged immediately as it's blocking all forward
progress due to the queue draining.

Most filesystems already get this implicitly by the way how submit_bh
treats the buffer_ordered flag, and gfs2 sets it explicitly. But btrfs
and XFS are still forgetting to set the flag, as is blkdev_issue_flush
and some places in DM/MD.

For XFS on metadata heavy workloads this gives a consistent speedup
in the 2-3% range.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

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GFS2: Rework reclaiming unlinked dinodes

The previous patch I wrote for reclaiming unlinked dinodes
had some shortcomings and did not prevent all hangs.
This version is much cleaner and more logical

GFS2: Rework reclaiming unlinked dinodes

The previous patch I wrote for reclaiming unlinked dinodes
had some shortcomings and did not prevent all hangs.
This version is much cleaner and more logical, and has
passed very difficult testing. Sorry for the churn.

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

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GFS2: Add some useful messages

The following patch adds a message to indicate when barriers have been
disabled due to a block device which doesn't support them. You could
already tell this via the m

GFS2: Add some useful messages

The following patch adds a message to indicate when barriers have been
disabled due to a block device which doesn't support them. You could
already tell this via the mount options in /proc/mounts, but all the
other filesystems also log a message at the same time.

Also, the same mechanisms are used to indicate when the lock
demote interface has been used (only ever used for debugging)
which is a request from our support team.

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

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