commit d53ba474
(Btrfs: use commit root when loading free space cache) has remove
the deadlock check, and the related comments can be removed as well.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

If we start running low on metadata space we will try to allocate a chunk,
which could then try to allocate a chunk to add the device entry.  The thing
is we allocate a chunk before we try really hard to make the allocation, so
we should be able to find space for the device entry.  Add a flag to the
trans handle so we know we're currently allocating a chunk so we can just
bail out if we try to allocate another chunk.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

We may try to flush some dirty pages when there is no enough space to reserve.
But it is possible that this operation fails, in order to get enough space to
reserve successfully, we will sync all the delalloc file. This operation is
safe, we needn't worry about the case that the filesystem goes from r/w to r/o.
because the filesystem should guarantee all the dirty pages have been written
into the disk after it becomes readonly, so the sync operation will do nothing
if the filesystem is already readonly. Though it may waste lots of time,
as a corner case, we needn't care.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

Locking and unlocking delayed ref mutex are in the different functions,
and the name of lock functions is not uniform, so the readability is not
so good, this patch optimizes the lock logic and makes it more readable.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

The delayed reference allocation is in the fast path of the IO, so use slabs
to improve the speed of the allocation.

And besides that, it can do check for leaked objects when the module is removed.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>

When btrfs_qgroup_reserve returned a failure, we were missing a counter
operation for BTRFS_I(inode)->outstanding_extents++, leading to warning
messages about outstanding extents and space_info->bytes_may_use != 0.
Additionally, the error handling code didn't take into account that we
dropped the inode lock which might require more cleanup.

Luckily, all the cleanup code we need is already there and can be shared
with reserve_metadata_bytes, which is exactly what this patch does.
Reported-by: NLev Vainblat <lev@zadarastorage.com>
Signed-off-by: NJan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

We forgot to reset the path lock state to zero after we unlock the path block,
and this can lead to the ASSERT checker in tree unlock API.
Reported-by: NSlava Barinov <rayslava@gmail.com>
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

This'd avoid us empty looping.

Say we have only one disk and the metadata raid type will be defaultly DUP,
and we do not need to start from index=0(RAID10) and get over two empty
loops to index=2(DUP).
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

We still need to say we're flushing if we're limit flushing to keep somebody
from coming in and stealing our reservation.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

This confuses and angers lockdep even though it's ok.  We don't really need
the lock for free space inodes since only the transaction committer will be
reserving space.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

This happens because writeback_inodes_sb_nr_if_idle does down_read.  This
doesn't work for us and it has not been fixed upstream yet, so do it
ourselves and use that instead so we can stop having this stupid long
standing lockup.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Raid properties can be shared among raid calculation code, we can put
them into a global table to keep it simple.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

We forget to release the reserved space in the error path of delalloc
reservatiom, fix it.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

This patch adds some code to disallow operations on the device that
is used as the target for the device replace operation.
Signed-off-by: NStefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

This is required for the device replace procedure in a later step.
Two calling functions also had to be changed to have the fs_info
pointer: repair_io_failure() and scrub_setup_recheck_block().
Signed-off-by: NStefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

When committing a transaction, we may bail out of running delayed refs
due to ENOSPC, and then abort the current transaction to flip into readonly.

But we'll hit a deadlock on ref head's lock since we forget to release
its lock and other cleanup stuff.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Use WARN rather than printk followed by WARN_ON(1), for conciseness.

A simplified version of the semantic patch that makes this transformation
is as follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
expression list es;
@@

-printk(
+WARN(1,
  es);
-WARN_ON(1);
// </smpl>
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Dave gave me an image of a very full file system that would abort the
transaction because it ran out of space while committing the transaction.
This is because we would think there was plenty of room to create a snapshot
even though the global reserve was not full.  This happens because we
calculate the global reserve size before we unpin any space, so after we
unpin the space we allow reservations to occur even though we haven't
reserved all of the space for our global reserve.  Fix this by adding to the
global reserve while unpinning in order to make sure we always have enough
space to do our work.  With this patch we no longer end up with an aborted
transaction, we return ENOSPC properly to the person trying to create the
snapshot.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

In some places(such as: evicting inode), we just can not flush the reserved
space of delalloc, flushing the delayed directory index and delayed inode
is OK, but we don't try to flush those things and just go back when there is
no enough space to be reserved. This patch fixes this problem.

We defined 3 types of the flush operations: NO_FLUSH, FLUSH_LIMIT and FLUSH_ALL.
If we can in the transaction, we should not flush anything, or the deadlock
would happen, so use NO_FLUSH. If we flushing the reserved space of delalloc
would cause deadlock, use FLUSH_LIMIT. In the other cases, FLUSH_ALL is used,
and we will flush all things.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

The comment is not coincident with the code. Fix it.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

div_factor{_fine} has been implemented for two times, cleanup it.
And I move them into a independent file named math.h because they are
common math functions.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

I don't think we have the same problem that this was supposed to fix
originally since we can allocate chunks in the enospc path now.  This code
is causing us to constantly commit the transaction as we get close to using
all of our available space in our currently allocated chunks, instead of
allocating another chunk and carrying on with life, which is not nice for
performance.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

Everytime we write out dirty pages we search for an offset in the tree,
convert the bits in the state, and then when we wait we search for the
offset again and clear the bits.  So for every dirty range in the io tree we
are doing 4 rb searches, which is suboptimal.  With this patch we are only
doing 2 searches for every cycle (modulo weird things happening).  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

Running delayed refs is faster than running delalloc, so lets do that first
to try and reclaim space.  This makes my fs_mark test about 20% faster.
Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

Call btrfs_abort_transaction as early as possible when an error
condition is detected, that way the line number reported is useful
and we're not clueless anymore which error path led to the abort.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>

nocow_only is now an obsolete argument.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>

There is already an 'add free space' phrase in front of this one, we
needn't to redo it.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>

Everybody is just making stuff up, and it's just used to see if we really do
need to alloc a chunk, and since we do this when we already know we really
do it's just a waste of space.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

So we have lots of places where we try to preallocate chunks in order to
make sure we have enough space as we make our allocations.  This has
historically meant that we're constantly tweaking when we should allocate a
new chunk, and historically we have gotten this horribly wrong so we way
over allocate either metadata or data.  To try and keep this from happening
we are going to make it so that the block group item insertion is done out
of band at the end of a transaction.  This will allow us to create chunks
even if we are trying to make an allocation for the extent tree.  With this
patch my enospc tests run faster (didn't expect this) and more efficiently
use the disk space (this is what I wanted).  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

I noticed I was seeing large lags when running my torrent test in a vm on my
laptop.  While trying to make it lag less I noticed that our overcommit math
was taking into account the number of bytes we wanted to reclaim, not the
number of bytes we actually wanted to allocate, which means we wouldn't
overcommit as often.  This patch fixes the overcommit math and makes
shrink_delalloc() use that logic so that it will stop looping faster.  We
still have pretty high spikes of latency, but the test now takes 3 minutes
less time (about 5% faster).  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

Mitch reported a problem where you could get an ENOSPC error when untarring
a kernel git tree onto a 16gb file system with compress-force=zlib.  This is
because compression is a huge pain, it will return from ->writepages()
without having actually created any ordered extents.  To get around this we
check to see if the async submit counter is up, and if it is wait until it
drops to 0 before doing our normal ordered wait dance.  With this patch I
can now untar a kernel git tree onto a 16gb file system without getting
ENOSPC errors.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

We should insert/update 6 items(root ref, root backref, dir item, dir index,
root item and parent inode) when creating a snapshot, not 5 items, fix it.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>

Sometimes we need choose the method of the reservation according to the type
of the block reservation, such as the reservation for the delayed inode update.
Now we identify the type just by comparing the address of the reservation
variants, it is very ugly if it is a temporary one because we need compare it
with all the common reservation variants. So we add a new "type" field to keep
the type the reservation variants.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>

This patch adds hole punching via fallocate.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

We will stop and restart a transaction every time we move to a different leaf
when truncating a file.  This is for enospc reasons, but really we could
probably get away with doing this a little better by actually working until we
hit an ENOSPC.  So add a ->failfast flag to the block_rsv and set it when we do
truncates which will fail as soon as the block rsv runs out of space, and then
at that point we can stop and restart the transaction and refill the block rsv
and carry on.  This will make rm'ing of a file with lots of extents a bit
faster.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

Swinging this pendulum back the other way.  We've been allocating chunks up
to 2% of the disk no matter how much we actually have allocated.  So instead
fix this calculation to only allocate chunks if we have more than 80% of the
space available allocated.  Please test this as it will likely cause all
sorts of ENOSPC problems to pop up suddenly.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

Daniel Blueman reported a bug with fio+balance on a ramdisk setup.
Basically what happens is the balance relocates a tree block which will drop
the implicit refs for all of its children and adds a full backref.  Once the
block is relocated we have to add the implicit refs back, so when we cow the
block again we add the implicit refs for its children back.  The problem
comes when the original drop ref doesn't get run before we add the implicit
refs back.  The delayed ref stuff will specifically prefer ADD operations
over DROP to keep us from freeing up an extent that will have references to
it, so we try to add the implicit ref before it is actually removed and we
panic.  This worked fine before because the add would have just canceled the
drop out and we would have been fine.  But the backref walking work needs to
be able to freeze the delayed ref stuff in time so we have this ever
increasing sequence number that gets attached to all new delayed ref updates
which makes us not merge refs and we run into this issue.

So to fix this we need to merge delayed refs.  So everytime we run a
clustered ref we need to try and merge all of its delayed refs.  The backref
walking stuff locks the delayed ref head before processing, so if we have it
locked we are safe to merge any refs inside of the sequence number.  If
there is no sequence number we can merge all refs.  Doing this not only
fixes our bug but keeps the delayed ref code from adding and removing
useless refs and batching together multiple refs into one search instead of
one search per delayed ref, which will really help our commit times.  I ran
this with Daniels test and 276 and I haven't seen any problems.  Thanks,
Reported-by: NDaniel J Blueman <daniel@quora.org>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

With commit

commit d1270cd9
Author: Arne Jansen <sensille@gmx.net>
Date:   Tue Sep 13 15:16:43 2011 +0200

     Btrfs: put back delayed refs that are too new

I added a window where the delayed_ref's head->ref_mod code can diverge
from the sum of the remaining refs, because we release the head->mutex
in the middle. This leads to btrfs_lookup_extent_info returning wrong
numbers. This patch fixes this by adjusting the head's ref_mod with each
delayed ref we run.
Signed-off-by: NArne Jansen <sensille@gmx.net>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Arne was complaining about the space cache having mismatching generation
numbers when debugging a deadlock.  This is because we can run out of space
in our preallocated range for our space cache if you have a pretty
fragmented amount of space in your pinned space.  So just increase the
amount of space we preallocate for space cache so we can be sure to have
enough space.  This will only really affect data ranges since their the only
chunks that end up larger than 256MB.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Commit a168650c introduced a waiting mechanism to prevent busy waiting in
btrfs_run_delayed_refs. This can deadlock with btrfs_run_ordered_operations,
where a tree_mod_seq is held while waiting for the io to complete, while
the end_io calls btrfs_run_delayed_refs.
This whole mechanism is unnecessary. If not enough runnable refs are
available to satisfy count, just return as count is more like a guideline
than a strict requirement.
In case we have to run all refs, commit transaction makes sure that no
other threads are working in the transaction anymore, so we just assert
here that no refs are blocked.
Signed-off-by: NArne Jansen <sensille@gmx.net>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>