1. Andreas Gruenbacher has four patches related to cleaning up the GFS2
inode evict process. This is about half of his patches designed to
fix a long-standing GFS2 hang related to the inode shrinker.
(Shrinker calls gfs2 evict, evict calls DLM, DLM requires memory
and blocks on the shrinker.) These 4 patches have been well tested.
His second set of patches are still being tested, so I plan to hold
them until the next merge window, after we have more weeks of testing.
The first patch eliminates the flush_delayed_work, which can block.
2. Andreas's second patch protects setting of gl_object for rgrps with
a spin_lock to prevent proven races.
3. His third patch introduces a centralized mechanism for queueing glock
work with better reference counting, to prevent more races.
4. His fourth patch retains a reference to inode glocks when an error
occurs while creating an inode. This keeps the subsequent evict from
needing to reacquire the glock, which might call into DLM and block
in low memory conditions.
5. Arvind Yadav has a patch to add const to attribute_group structures.
6. I have a patch to detect directory entry inconsistencies and withdraw
the file system if any are found. Better that than silent corruption.
7. I have a patch to remove a vestigial variable from glock structures,
saving some slab space.
8. I have another patch to remove a vestigial variable from the GFS2
in-core superblock structure.
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Merge tag 'gfs2-4.13.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
Pull GFS2 updates from Bob Peterson:
"We've got eight GFS2 patches for this merge window:
- Andreas Gruenbacher has four patches related to cleaning up the
GFS2 inode evict process. This is about half of his patches
designed to fix a long-standing GFS2 hang related to the inode
shrinker: Shrinker calls gfs2 evict, evict calls DLM, DLM requires
memory and blocks on the shrinker.
These four patches have been well tested. His second set of patches
are still being tested, so I plan to hold them until the next merge
window, after we have more weeks of testing. The first patch
eliminates the flush_delayed_work, which can block.
- Andreas's second patch protects setting of gl_object for rgrps with
a spin_lock to prevent proven races.
- His third patch introduces a centralized mechanism for queueing
glock work with better reference counting, to prevent more races.
-His fourth patch retains a reference to inode glocks when an error
occurs while creating an inode. This keeps the subsequent evict
from needing to reacquire the glock, which might call into DLM and
block in low memory conditions.
- Arvind Yadav has a patch to add const to attribute_group
structures.
- I have a patch to detect directory entry inconsistencies and
withdraw the file system if any are found. Better that than silent
corruption.
- I have a patch to remove a vestigial variable from glock
structures, saving some slab space.
- I have another patch to remove a vestigial variable from the GFS2
in-core superblock structure"
* tag 'gfs2-4.13.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
GFS2: constify attribute_group structures.
gfs2: gfs2_create_inode: Keep glock across iput
gfs2: Clean up glock work enqueuing
gfs2: Protect gl->gl_object by spin lock
gfs2: Get rid of flush_delayed_work in gfs2_evict_inode
GFS2: Eliminate vestigial sd_log_flush_wrapped
GFS2: Remove gl_list from glock structure
GFS2: Withdraw when directory entry inconsistencies are detected
Commit b685d3d65a "block: treat REQ_FUA and REQ_PREFLUSH as
synchronous" removed REQ_SYNC flag from WRITE_{FUA|PREFLUSH|...}
definitions. generic_make_request_checks() however strips REQ_FUA and
REQ_PREFLUSH flags from a bio when the storage doesn't report volatile
write cache and thus write effectively becomes asynchronous which can
lead to performance regressions
Fix the problem by making sure all bios which are synchronous are
properly marked with REQ_SYNC.
Fixes: b685d3d65a
CC: Steven Whitehouse <swhiteho@redhat.com>
CC: cluster-devel@redhat.com
CC: stable@vger.kernel.org
Acked-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
1. Andy Price submitted a patch to make gfs2_write_full_page a
static function.
2. Dan Carpenter submitted a patch to fix a ERR_PTR thinko.
I've also got a few patches, three of which fix bugs related to
deleting very large files, which cause GFS2 to run out of
journal space:
3. The first one prevents GFS2 delete operation from requesting too
much journal space.
4. The second one fixes a problem whereby GFS2 can hang because it
wasn't taking journal space demand into its calculations.
5. The third one wakes up IO waiters when a flush is done to restart
processes stuck waiting for journal space to become available.
The other three patches are a performance improvement related to
spin_lock contention between multiple writers:
6. The "tr_touched" variable was switched to a flag to be more atomic
and eliminate the possibility of some races.
7. Function meta_lo_add was moved inline with its only caller to make
the code more readable and efficient.
8. Contention on the gfs2_log_lock spinlock was greatly reduced by
avoiding the lock altogether in cases where we don't really need
it: buffers that already appear in the appropriate metadata list
for the journal. Many thanks to Steve Whitehouse for the ideas and
principles behind these patches.
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Merge tag 'gfs2-4.11.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
Pull GFS2 updates from Robert Peterson:
"We've got eight GFS2 patches for this merge window:
- Andy Price submitted a patch to make gfs2_write_full_page a static
function.
- Dan Carpenter submitted a patch to fix a ERR_PTR thinko.
Three patches fix bugs related to deleting very large files, which
cause GFS2 to run out of journal space:
- The first one prevents GFS2 delete operation from requesting too
much journal space.
- The second one fixes a problem whereby GFS2 can hang because it
wasn't taking journal space demand into its calculations.
- The third one wakes up IO waiters when a flush is done to restart
processes stuck waiting for journal space to become available.
The final three patches are a performance improvement related to
spin_lock contention between multiple writers:
- The "tr_touched" variable was switched to a flag to be more atomic
and eliminate the possibility of some races.
- Function meta_lo_add was moved inline with its only caller to make
the code more readable and efficient.
- Contention on the gfs2_log_lock spinlock was greatly reduced by
avoiding the lock altogether in cases where we don't really need
it: buffers that already appear in the appropriate metadata list
for the journal. Many thanks to Steve Whitehouse for the ideas and
principles behind these patches"
* tag 'gfs2-4.11.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
gfs2: Make gfs2_write_full_page static
GFS2: Reduce contention on gfs2_log_lock
GFS2: Inline function meta_lo_add
GFS2: Switch tr_touched to flag in transaction
GFS2: Wake up io waiters whenever a flush is done
GFS2: Made logd daemon take into account log demand
GFS2: Limit number of transaction blocks requested for truncates
GFS2: Fix reference to ERR_PTR in gfs2_glock_iter_next
This patch eliminates the int variable tr_touched in favor of a
new flag in the transaction. This is a step toward reducing contention
on the gfs2_log_lock spin_lock.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Before this patch, if a process called function gfs2_log_reserve to
reserve some journal blocks, but the journal not enough blocks were
free, it would call io_schedule. However, in the log flush daemon,
it woke up the waiters only if an gfs2_ail_flush was no longer
required. This resulted in situations where processes would wait
forever because the number of blocks required was so high that it
pushed the journal into a perpetual state of flush being required.
This patch changes the logd daemon so that it wakes up io waiters
every time the log is actually flushed.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Before this patch, the logd daemon only tried to flush things when
the log blocks pinned exceeded a certain threshold. But when we're
deleting very large files, it may require a huge number of journal
blocks, and that, in turn, may exceed the threshold. This patch
factors that into account.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Remove the WRITE_* and READ_SYNC wrappers, and just use the flags
directly. Where applicable this also drops usage of the
bio_set_op_attrs wrapper.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Separate the op from the rq_flag_bits and have gfs2
set/get the bio using bio_set_op_attrs/bio_op.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
When gfs2 was unmounting filesystems or changing them to read-only it
was clearing the SDF_JOURNAL_LIVE bit before the final log flush. This
caused a race. If an inode glock got demoted in the gap between
clearing the bit and the shutdown flush, it would be unable to reserve
log space to clear out the active items list in inode_go_sync, causing an
error in inode_go_inval because the glock was still dirty.
To solve this, the SDF_JOURNAL_LIVE bit is now cleared inside the
shutdown log flush. This means that, because of the locking on the log
blocks, either inode_go_sync will be able to reserve space to clean the
glock before the shutdown flush, or the shutdown flush will clean the
glock itself, before inode_go_sync fails to reserve the space. Either
way, the glock will be clean before inode_go_inval.
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
The current gfs2 freezing code is considerably more complicated than it
should be because it doesn't use the vfs freezing code on any node except
the one that begins the freeze. This is because it needs to acquire a
cluster glock before calling the vfs code to prevent a deadlock, and
without the new freeze_super and thaw_super hooks, that was impossible. To
deal with the issue, gfs2 had to do some hacky locking tricks to make sure
that a frozen node couldn't be holding on a lock it needed to do the
unfreeze ioctl.
This patch makes use of the new hooks to simply the gfs2 locking code. Now,
all the nodes in the cluster freeze and thaw in exactly the same way. Every
node in the cluster caches the freeze glock in the shared state. The new
freeze_super hook allows the freezing node to grab this freeze glock in
the exclusive state without first calling the vfs freeze_super function.
All the nodes in the cluster see this lock change, and call the vfs
freeze_super function. The vfs locking code guarantees that the nodes can't
get stuck holding the glocks necessary to unfreeze the system. To
unfreeze, the freezing node uses the new thaw_super hook to drop the freeze
glock. Again, all the nodes notice this, reacquire the glock in shared mode
and call the vfs thaw_super function.
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
GFS2 has a transaction glock, which must be grabbed for every
transaction, whose purpose is to deal with freezing the filesystem.
Aside from this involving a large amount of locking, it is very easy to
make the current fsfreeze code hang on unfreezing.
This patch rewrites how gfs2 handles freezing the filesystem. The
transaction glock is removed. In it's place is a freeze glock, which is
cached (but not held) in a shared state by every node in the cluster
when the filesystem is mounted. This lock only needs to be grabbed on
freezing, and actions which need to be safe from freezing, like
recovery.
When a node wants to freeze the filesystem, it grabs this glock
exclusively. When the freeze glock state changes on the nodes (either
from shared to unlocked, or shared to exclusive), the filesystem does a
special log flush. gfs2_log_flush() does all the work for flushing out
the and shutting down the incore log, and then it tries to grab the
freeze glock in a shared state again. Since the filesystem is stuck in
gfs2_log_flush, no new transaction can start, and nothing can be written
to disk. Unfreezing the filesytem simply involes dropping the freeze
glock, allowing gfs2_log_flush() to grab and then release the shared
lock, so it is cached for next time.
However, in order for the unfreezing ioctl to occur, gfs2 needs to get a
shared lock on the filesystem root directory inode to check permissions.
If that glock has already been grabbed exclusively, fsfreeze will be
unable to get the shared lock and unfreeze the filesystem.
In order to allow the unfreeze, this patch makes gfs2 grab a shared lock
on the filesystem root directory during the freeze, and hold it until it
unfreezes the filesystem. The functions which need to grab a shared
lock in order to allow the unfreeze ioctl to be issued now use the lock
grabbed by the freeze code instead.
The freeze and unfreeze code take care to make sure that this shared
lock will not be dropped while another process is using it.
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Upstream commit 34cc178 changed a line of code from calling function
log_flush_commit to calling log_write_header. This had the effect of
eliminating a call to function log_flush_wait. That causes the journal
to skip over log headers, which results in multiple wrap points,
which itself leads to infinite loops in journal replay, both in the
kernel code and fsck.gfs2 code. This patch re-adds that call.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
By reordering some of the assignments in gfs2_log_flush() it
is possible to remove one of the "if" statements as it can be
merged with one higher up the function.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Now we have a master transaction into which other transactions
are merged, the accounting can be done using this master
transaction. We no longer require the superblock fields which
were being used for this function.
In addition, this allows for a clean up in calc_reserved()
making it rather easier understand. Also, by reducing the
number of variables used to track the buffers being added
and removed from the journal, a number of error checks are
now no longer required.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Over time, we hope to be able to improve the concurrency available
in the log code. This is one small step towards that, by moving
the buffer lists from the super block, and into the transaction
structure, so that each transaction builds its own buffer lists.
At transaction commit time, the buffer lists are merged into
the currently accumulating transaction. That transaction then
is passed into the before and after commit functions at journal
flush time. Thus there should be no change in overall behaviour
yet.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
When we do a flush of the AIL list, we are writing out what is
likely to be a lot of small I/Os, which are possibly in an order
which is not ideal performance-wise. Since this is done by calling
filemap_fdatatwrite for each individual inode's address space there
is no overall plugging going on.
In addition to that, we do not always wait for AIL i/o when we flush
it, so that it is possible for things to get left behind on the queue.
By adding explicit plugging here, we reduce the chances of this
being an issues. A quick test using the AIL flush tracepoint shows a
small, but measurable improvement.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Function gfs2_remove_from_ail drops the reference on the bh via
brelse. This patch fixes a race condition whereby bh is deferenced
after the brelse when setting bd->bd_blkno = bh->b_blocknr;
Under certain rare circumstances, bh might be gone or reused,
and bd->bd_blkno is set to whatever that memory happens to be,
which is often 0. Later, in gfs2_trans_add_unrevoke, that bd fails
the test "bd->bd_blkno >= blkno" which causes it to never be freed.
The end result is that the bd is never freed from the bufdata cache,
which results in this error:
slab error in kmem_cache_destroy(): cache `gfs2_bufdata': Can't free all objects
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This patch looks at all the outstanding blocks in all the transactions
on the log, and moves the completed ones to the ail2 list. Then it
issues revokes for these blocks. This will hopefully speed things up
in situations where there is a lot of contention for glocks, especially
if they are acquired serially.
revoke_lo_before_commit will issue at most one log block's full of these
preemptive revokes. The amount of reserved log space that
gfs2_log_reserve() ignores has been incremented to allow for this extra
block.
This patch also consolidates the common revoke instructions into one
function, gfs2_add_revoke().
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
In order to allow transactions and log flushes to happen at the same
time, gfs2 needs to move the transaction accounting and active items
list code into the gfs2_trans structure. As a first step toward this,
this patch removes the gfs2_ail structure, and handles the active items
list in the gfs_trans structure. This keeps gfs2 from allocating an ail
structure on log flushes, and gives us a struture that can later be used
to store the transaction accounting outside of the gfs2 superblock
structure.
With this patch, at the end of a transaction, gfs2 will add the
gfs2_trans structure to the superblock if there is not one already.
This structure now has the active items fields that were previously in
gfs2_ail. This is not necessary in the case where the transaction was
simply used to add revokes, since these are never written outside of the
journal, and thus, don't need an active items list.
Also, in order to make sure that the transaction structure is not
removed while it's still in use by gfs2_trans_end, unlocking the
sd_log_flush_lock has to happen slightly later in ending the
transaction.
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Instead of using a list of buffers to write ahead of the journal
flush, this now uses a list of inodes and calls ->writepages
via filemap_fdatawrite() in order to achieve the same thing. For
most use cases this results in a shorter ordered write list,
as well as much larger i/os being issued.
The ordered write list is sorted by inode number before writing
in order to retain the disk block ordering between inodes as
per the previous code.
The previous ordered write code used to conflict in its assumptions
about how to write out the disk blocks with mpage_writepages()
so that with this updated version we can also use mpage_writepages()
for GFS2's ordered write, writepages implementation. So we will
also send larger i/os from writeback too.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This patch eliminates the gfs2_log_element data structure and
rolls its two components into the gfs2_bufdata. This makes the code
easier to understand and makes it easier to migrate to a rbtree
to keep the list sorted.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This patch removes a log lock from around atomic operation where
it is not needed, removes an unused variable, and also changes
a void pointer used incorrectly to a struct page pointer.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
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>
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>
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>
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>
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>
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>
* 'pm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (76 commits)
PM / Hibernate: Implement compat_ioctl for /dev/snapshot
PM / Freezer: fix return value of freezable_schedule_timeout_killable()
PM / shmobile: Allow the A4R domain to be turned off at run time
PM / input / touchscreen: Make st1232 use device PM QoS constraints
PM / QoS: Introduce dev_pm_qos_add_ancestor_request()
PM / shmobile: Remove the stay_on flag from SH7372's PM domains
PM / shmobile: Don't include SH7372's INTCS in syscore suspend/resume
PM / shmobile: Add support for the sh7372 A4S power domain / sleep mode
PM: Drop generic_subsys_pm_ops
PM / Sleep: Remove forward-only callbacks from AMBA bus type
PM / Sleep: Remove forward-only callbacks from platform bus type
PM: Run the driver callback directly if the subsystem one is not there
PM / Sleep: Make pm_op() and pm_noirq_op() return callback pointers
PM/Devfreq: Add Exynos4-bus device DVFS driver for Exynos4210/4212/4412.
PM / Sleep: Merge internal functions in generic_ops.c
PM / Sleep: Simplify generic system suspend callbacks
PM / Hibernate: Remove deprecated hibernation snapshot ioctls
PM / Sleep: Fix freezer failures due to racy usermodehelper_is_disabled()
ARM: S3C64XX: Implement basic power domain support
PM / shmobile: Use common always on power domain governor
...
Fix up trivial conflict in fs/xfs/xfs_buf.c due to removal of unused
XBT_FORCE_SLEEP bit
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>
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>
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>
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>
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>
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>
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>
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>
* 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block: (65 commits)
Documentation/iostats.txt: bit-size reference etc.
cfq-iosched: removing unnecessary think time checking
cfq-iosched: Don't clear queue stats when preempt.
blk-throttle: Reset group slice when limits are changed
blk-cgroup: Only give unaccounted_time under debug
cfq-iosched: Don't set active queue in preempt
block: fix non-atomic access to genhd inflight structures
block: attempt to merge with existing requests on plug flush
block: NULL dereference on error path in __blkdev_get()
cfq-iosched: Don't update group weights when on service tree
fs: assign sb->s_bdi to default_backing_dev_info if the bdi is going away
block: Require subsystems to explicitly allocate bio_set integrity mempool
jbd2: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging
jbd: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging
fs: make fsync_buffers_list() plug
mm: make generic_writepages() use plugging
blk-cgroup: Add unaccounted time to timeslice_used.
block: fixup plugging stubs for !CONFIG_BLOCK
block: remove obsolete comments for blkdev_issue_zeroout.
blktrace: Use rq->cmd_flags directly in blk_add_trace_rq.
...
Fix up conflicts in fs/{aio.c,super.c}
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>
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>
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>
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>
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>
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>
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>
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>
Linus Torvalds