When called during mount, we cannot start the rescan worker thread until
open_ctree is done. This commit restuctures the qgroup rescan internals to
enable a clean deferral of the rescan resume operation.

First of all, the struct qgroup_rescan is removed, saving us a malloc and
some initialization synchronizations problems. Its only element (the worker
struct) now lives within fs_info just as the rest of the rescan code.

Then setting up a rescan worker is split into several reusable stages.
Currently we have three different rescan startup scenarios:
	(A) rescan ioctl
	(B) rescan resume by mount
	(C) rescan by quota enable

Each case needs its own combination of the four following steps:
	(1) set the progress [A, C: zero; B: state of umount]
	(2) commit the transaction [A]
	(3) set the counters [A, C: zero; B: state of umount]
	(4) start worker [A, B, C]

qgroup_rescan_init does step (1). There's no extra function added to commit
a transaction, we've got that already. qgroup_rescan_zero_tracking does
step (3). Step (4) is nothing more than a call to the generic
btrfs_queue_worker.

We also get rid of a double check for the rescan progress during
btrfs_qgroup_account_ref, which is no longer required due to having step 2
from the list above.

As a side effect, this commit prepares to move the rescan start code from
btrfs_run_qgroups (which is run during commit) to a less time critical
section.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

When btrfs_read_qgroup_config or btrfs_quota_enable return non-zero, we've
already freed the fs_info->qgroup_ulist. The final btrfs_free_qgroup_config
called from quota_disable makes another ulist_free(fs_info->qgroup_ulist)
call.

We set fs_info->qgroup_ulist to NULL on the mentioned error paths, turning
the ulist_free in btrfs_free_qgroup_config into a noop.

Cc: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

Commit 5b7c665e introduced fs_info->qgroup_ulist, that is allocated during
btrfs_read_qgroup_config and meant to be used later by the qgroup accounting
code. However, it is always freed before btrfs_read_qgroup_config returns,
becuase the commit mentioned above adds a check for (ret), where a check
for (ret < 0) would have been the right choice. This commit fixes the check.

Cc: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

Dave pointed out a problem where if you filled up a file system as much as
possible you couldn't remove any files.  The whole unlink reservation thing is
convoluted because it tries to guess if it's going to add space to unlink
something or not, and has all these odd uncommented cases where it simply does
not try.  So to fix this I've added a way to conditionally steal from the global
reserve if we can't make our normal reservation.  If we have more than half the
space in the global reserve free we will go ahead and steal from the global
reserve.  With this patch Dave's reproducer now works and I can rm all the files
on the file system.  Thanks,
Reported-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

Before applying this patch, we flushed the log tree of the fs/file
tree firstly, and then flushed the log root tree. It is ineffective,
especially on the hard disk. This patch improved this problem by wrapping
the above two flushes by the same blk_plug.

By test, the performance of the sync write went up ~60%(2.9MB/s -> 4.6MB/s)
on my scsi disk whose disk buffer was enabled.

Test step:
 # mkfs.btrfs -f -m single <disk>
 # mount <disk> <mnt>
 # dd if=/dev/zero of=<mnt>/file0 bs=32K count=1024 oflag=sync
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

We did not allow file data clone within the same file because of
deadlock issues.

However, we now use nested lock to avoid deadlock between the
parent directory and the child file.

So it's safe to do file clone within the same file when the two
ranges are not overlapped.
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

'leaf' and 'ri' is not used somehow.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

EXTREF is treated same as REF, so we can make the code tidy.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

Adding new flags to keep tracepoints consistent with btrfs.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

During splitting a leaf, pushing items around to hopefully get some space only
works when we have a parent, ie. we have at least one sibling leaf.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

As for splitting a leaf, root is just the leaf, and tree mod log does not apply
on leaf, so in this case, we don't do log_removal.

As for splitting a node, the old root is kept as a normal node and we have nicely
put records in tree mod log for moving keys and items, so in this case we don't do
that either.

As above, insert_new_root can get rid of log_removal.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

Fix to return error code instead always return 0 from function
btrfs_check_trunc_cache_free_space().
Introduced by commit 7b61cd92
(Btrfs: don't use global block reservation for inode cache truncation)
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

This fixes bugzilla 57491.  If we take a snapshot of a fs with a unlink ongoing
and then try to send that root we will run into problems.  When comparing with a
parent root we will search the parents and the send roots commit_root, which if
we've just created the snapshot will include the file that needs to be evicted
by the orphan cleanup.  So when we find a changed extent we will try and copy
that info into the send stream, but when we lookup the inode we use the normal
root, which no longer has the inode because the orphan cleanup deleted it.  The
best solution I have for this is to check our otransid with the generation of
the commit root and if they match just commit the transaction again, that way we
get the changes from the orphan cleanup.  With this patch the reproducer I made
for this bugzilla no longer returns ESTALE when trying to do the send.  Thanks,

Cc: stable@vger.kernel.org
Reported-by: Chris Wilson <jakdaw@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

when user runs command btrfs dev del the raid requisite error if any
goes to the /var/log/messages, its not good idea to clutter messages
with these user (knowledge) errors, further user don't have to review
the system messages to know problem with the cli it should be dropped
to the user as part of the cli return.

to bring this feature created a set of the ERROR defined
BTRFS_ERROR_DEV* error codes and created their error string.

I expect this enum to be added with other error which we might
want to communicate to the user land

v3:
moved the code with in the file no logical change

v1->v2:
introduce error codes for the device mgmt usage

v1:
adds a parameter in the ioctl arg struct to carry the error string
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

We get lock inversion with umount if we allow iputs from sync_fs, so use the
delay iput flag to keep this from happening.  Thanks,
Reported-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

We used 3 variants to track the state of the transaction, it was complex
and wasted the memory space. Besides that, it was hard to understand that
which types of the transaction handles should be blocked in each transaction
state, so the developers often made mistakes.

This patch improved the above problem. In this patch, we define 6 states
for the transaction,
  enum btrfs_trans_state {
	TRANS_STATE_RUNNING		= 0,
	TRANS_STATE_BLOCKED		= 1,
	TRANS_STATE_COMMIT_START	= 2,
	TRANS_STATE_COMMIT_DOING	= 3,
	TRANS_STATE_UNBLOCKED		= 4,
	TRANS_STATE_COMPLETED		= 5,
	TRANS_STATE_MAX			= 6,
  }
and just use 1 variant to track those state.

In order to make the blocked handle types for each state more clear,
we introduce a array:
  unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
	[TRANS_STATE_RUNNING]		= 0U,
	[TRANS_STATE_BLOCKED]		= (__TRANS_USERSPACE |
					   __TRANS_START),
	[TRANS_STATE_COMMIT_START]	= (__TRANS_USERSPACE |
					   __TRANS_START |
					   __TRANS_ATTACH),
	[TRANS_STATE_COMMIT_DOING]	= (__TRANS_USERSPACE |
					   __TRANS_START |
					   __TRANS_ATTACH |
					   __TRANS_JOIN),
	[TRANS_STATE_UNBLOCKED]		= (__TRANS_USERSPACE |
					   __TRANS_START |
					   __TRANS_ATTACH |
					   __TRANS_JOIN |
					   __TRANS_JOIN_NOLOCK),
	[TRANS_STATE_COMPLETED]		= (__TRANS_USERSPACE |
					   __TRANS_START |
					   __TRANS_ATTACH |
					   __TRANS_JOIN |
					   __TRANS_JOIN_NOLOCK),
  }
it is very intuitionistic.

Besides that, because we remove ->in_commit in transaction structure, so
the lock ->commit_lock which was used to protect it is unnecessary, remove
->commit_lock.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

We checked the commit time to avoid committing the transaction
frequently, but it is unnecessary because:
- It made the transaction commit spend more time, and delayed the
  operation of the external writers(TRANS_START/TRANS_USERSPACE).
- Except the space that we have to commit transaction, such as
  snapshot creation, btrfs doesn't commit the transaction on its
  own initiative.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

We used ->num_joined track if there were some writers which join the current
transaction when the committer was sleeping. If some writers joined the current
transaction, we has to continue the while loop to do some necessary stuff, such
as flush the ordered operations. But it is unnecessary because we will do it
after the while loop.

Besides that, tracking ->num_joined would make the committer drop into the while
loop when there are lots of internal writers(TRANS_JOIN).

So we remove ->num_joined and don't track if there are some writers which join
the current transaction when the committer is sleeping.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

It is unnecessary to flush the delalloc inodes again and again because
we don't care the dirty pages which are introduced after the flush, and
they will be flush in the transaction commit.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

btrfs_commit_transaction has the following loop before we commit the
transaction.

do {
    // attempt to do some useful stuff and/or sleep
} while (atomic_read(&cur_trans->num_writers) > 1 ||
	 (should_grow && cur_trans->num_joined != joined));

This is used to prevent from the TRANS_START to get in the way of a
committing transaction. But it does not prevent from TRANS_JOIN, that
is we would do this loop for a long time if some writers JOIN the
current transaction endlessly.

Because we need join the current transaction to do some useful stuff,
we can not block TRANS_JOIN here. So we introduce a external writer
counter, which is used to count the TRANS_USERSPACE/TRANS_START writers.
If the external writer counter is zero, we can break the above loop.

In order to make the code more clear, we don't use enum variant
to define the type of the transaction handle, use bitmask instead.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

If the transaction is removed from the transaction list, it means the
transaction has been committed successfully. So it is impossible to
call cleanup_transaction(), otherwise there is something wrong with
the code logic. Thus, we use BUG_ON() instead of the original handle.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

When we umount a fs with serious errors, we will invoke btrfs_cleanup_transactions()
to clean up the residual transaction. At this time, It is impossible to start a new
transaction, so we needn't assign trans_no_join to 1, and also needn't clear running
transaction every time we destroy a residual transaction.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

Before applying this patch, we need flush all the delalloc inodes in
the fs when we want to create a snapshot, it wastes time, and make
the transaction commit be blocked for a long time. It means some other
user operation would also be blocked for a long time.

This patch improves this problem, we just flush the delalloc inodes that
in the source trees before snapshot creation, so the transaction commit
will complete quickly.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

The reason we introduce per-subvolume ordered extent list is the same
as the per-subvolume delalloc inode list.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

When we create a snapshot, we need flush all delalloc inodes in the
fs, just flushing the inodes in the source tree is OK. So we introduce
per-subvolume delalloc inode list.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

The grab/put funtions will be used in the next patch, which need grab
the root object and ensure it is not freed. We use reference counter
instead of the srcu lock is to aovid blocking the memory reclaim task,
which invokes synchronize_srcu().
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

There are several functions whose code is similar, such as
  btrfs_find_last_root()
  btrfs_read_fs_root_no_radix()

Besides that, some functions are invoked twice, it is unnecessary,
for example, we are sure that all roots which is found in
  btrfs_find_orphan_roots()
have their orphan items, so it is unnecessary to check the orphan
item again.

So cleanup it.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

The snapshot/subvolume deletion might spend lots of time, it would make
the remount task wait for a long time. This patch improve this problem,
we will break the deletion if the fs is remounted to be R/O. It will make
the users happy.

Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

If the fs is remounted to be R/O, it is unnecessary to call
btrfs_clean_one_deleted_snapshot(), so move the R/O check out of
this function. And besides that, it can make the check logic in the
caller more clear.

Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

In order to avoid the R/O remount, we acquired ->s_umount lock during
we deleted the dead snapshots and subvolumes. But it is unnecessary,
because we have cleaner_mutex.

We use cleaner_mutex to protect the process of the dead snapshots/subvolumes
deletion. And when we remount the fs to be R/O, we also acquire this mutex to
do cleanup after we change the status of the fs. That is this lock can serialize
the above operations, the cleaner can be aware of the status of the fs, and if
the cleaner is deleting the dead snapshots/subvolumes, the remount task will
wait for it. So it is safe to remove ->s_umount in cleaner_kthread().

Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

btrfs_read_fs_root_no_name() already checks if btrfs_root_refs()
is zero and returns ENOENT in this case. There is no need to do
it again in six places.
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

No need to check for NULL in send.c and disk-io.c.
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

We don't need to copy it back to user side as it remains unchanged.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

Clean up the format of the definitions of BTRFS_BLOCK_GROUP_RAID5 and
BTRFS_BLOCK_GROUP_RAID6.
Signed-off-by: Andreas Philipp <philipp.andreas@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

sctx is removed from the argument of the function that
doesn't use sctx.
Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

The size parameter to btrfs_extend_item() is the number of bytes
to add to the item, not the size of the item after the operation
(like it is for btrfs_truncate_item(), there the size parameter
is not the number of bytes to take away, but the total size of
the item after truncation).
Fix it in the comment.
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

btrfs_qgroup_wait_for_completion waits until the currently running qgroup
operation completes. It returns immediately when no rescan process is in
progress. This is useful to automate things around the rescan process (e.g.
testing).
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

When doing qgroup accounting, we call ulist_alloc()/ulist_free() every time
when we want to walk qgroup tree.

By introducing 'qgroup_ulist', we only need to call ulist_alloc()/ulist_free()
once. This reduce some sys time to allocate memory, see the measurements below

fsstress -p 4 -n 10000 -d $dir

With this patch:

real    0m50.153s
user    0m0.081s
sys     0m6.294s

real    0m51.113s
user    0m0.092s
sys     0m6.220s

real    0m52.610s
user    0m0.096s
sys     0m6.125s	avg 6.213
-----------------------------------------------------
Without the patch:

real    0m54.825s
user    0m0.061s
sys     0m10.665s

real    1m6.401s
user    0m0.089s
sys     0m11.218s

real    1m13.768s
user    0m0.087s
sys     0m10.665s       avg 10.849

we can see the sys time reduce ~43%.
Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>