This patch implement data repair function when direct read fails.

The detail of the implementation is:
- When we find the data is not right, we try to read the data from the other
  mirror.
- When the io on the mirror ends, we will insert the endio work into the
  dedicated btrfs workqueue, not common read endio workqueue, because the
  original endio work is still blocked in the btrfs endio workqueue, if we
  insert the endio work of the io on the mirror into that workqueue, deadlock
  would happen.
- After we get right data, we write it back to the corrupted mirror.
- And if the data on the new mirror is still corrupted, we will try next
  mirror until we read right data or all the mirrors are traversed.
- After the above work, we set the uptodate flag according to the result.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

device->bytes_used will be changed when allocating a new chunk, and
disk_total_size will be changed if resizing is successful.
Meanwhile, the on-disk super blocks of the previous transaction
might not be updated. Considering the consistency of the metadata
in the previous transaction, We should use the size in the previous
transaction to check if the super block is beyond the boundary
of the device.

Though it is not big problem because we don't use it now, but anyway
it is better that we make it be consistent with the common metadata,
maybe we will use it in the future.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

total_size will be changed when resizing a device, and disk_total_size
will be changed if resizing is successful. Meanwhile, the on-disk super
blocks of the previous transaction might not be updated. Considering
the consistency of the metadata in the previous transaction, We should
use the size in the previous transaction to check if the super block is
beyond the boundary of the device. Fix it.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

This comments became wrong after c3c532[bdi: add helper function for
doing init and register of a bdi for a file system], so remove them.
Signed-off-by: NLi RongQing <roy.qing.li@gmail.com>
Signed-off-by: NChris Mason <clm@fb.com>

The issue was introduced in a79b7d4b,
adding allocation of extent_workers, so this stray check is surely not
meant to be a check of something else.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=82021Reported-by: NMaks Naumov <maksqwe1@ukr.net>
Signed-off-by: NAndrey Utkin <andrey.krieger.utkin@gmail.com>
Reviewed-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: NChris Mason <clm@fb.com>

Marc argued that if there are several btrfs filesystems mounted,
while users even don't know which filesystem hit the corrupted
errors something like generation verification failure.

Since @extent_buffer structure has a member @fs_info, let's output
btrfs device info.
Reported-by: NMarc MERLIN <marc@merlins.org>
Signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

The nodesize and leafsize were never of different values. Unify the
usage and make nodesize the one. Cleanup the redundant checks and
helpers.

Shaves a few bytes from .text:

  text    data     bss     dec     hex filename
852418   24560   23112  900090   dbbfa btrfs.ko.before
851074   24584   23112  898770   db6d2 btrfs.ko.after
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

There's no user of the return value and we can get rid of the comment in
put_super.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

The naming is confusing, generic yet used for a specific cache. Add a
prefix 'ino_' or rename appropriately.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

This has been reported and discussed for a long time, and this hang occurs in
both 3.15 and 3.16.

Btrfs now migrates to use kernel workqueue, but it introduces this hang problem.

Btrfs has a kind of work queued as an ordered way, which means that its
ordered_func() must be processed in the way of FIFO, so it usually looks like --

normal_work_helper(arg)
    work = container_of(arg, struct btrfs_work, normal_work);

    work->func() <---- (we name it work X)
    for ordered_work in wq->ordered_list
            ordered_work->ordered_func()
            ordered_work->ordered_free()

The hang is a rare case, first when we find free space, we get an uncached block
group, then we go to read its free space cache inode for free space information,
so it will

file a readahead request
    btrfs_readpages()
         for page that is not in page cache
                __do_readpage()
                     submit_extent_page()
                           btrfs_submit_bio_hook()
                                 btrfs_bio_wq_end_io()
                                 submit_bio()
                                 end_workqueue_bio() <--(ret by the 1st endio)
                                      queue a work(named work Y) for the 2nd
                                      also the real endio()

So the hang occurs when work Y's work_struct and work X's work_struct happens
to share the same address.

A bit more explanation,

A,B,C -- struct btrfs_work
arg   -- struct work_struct

kthread:
worker_thread()
    pick up a work_struct from @worklist
    process_one_work(arg)
	worker->current_work = arg;  <-- arg is A->normal_work
	worker->current_func(arg)
		normal_work_helper(arg)
		     A = container_of(arg, struct btrfs_work, normal_work);

		     A->func()
		     A->ordered_func()
		     A->ordered_free()  <-- A gets freed

		     B->ordered_func()
			  submit_compressed_extents()
			      find_free_extent()
				  load_free_space_inode()
				      ...   <-- (the above readhead stack)
				      end_workqueue_bio()
					   btrfs_queue_work(work C)
		     B->ordered_free()

As if work A has a high priority in wq->ordered_list and there are more ordered
works queued after it, such as B->ordered_func(), its memory could have been
freed before normal_work_helper() returns, which means that kernel workqueue
code worker_thread() still has worker->current_work pointer to be work
A->normal_work's, ie. arg's address.

Meanwhile, work C is allocated after work A is freed, work C->normal_work
and work A->normal_work are likely to share the same address(I confirmed this
with ftrace output, so I'm not just guessing, it's rare though).

When another kthread picks up work C->normal_work to process, and finds our
kthread is processing it(see find_worker_executing_work()), it'll think
work C as a collision and skip then, which ends up nobody processing work C.

So the situation is that our kthread is waiting forever on work C.

Besides, there're other cases that can lead to deadlock, but the real problem
is that all btrfs workqueue shares one work->func, -- normal_work_helper,
so this makes each workqueue to have its own helper function, but only a
wraper pf normal_work_helper.

With this patch, I no long hit the above hang.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NChris Mason <clm@fb.com>

total_bytes of device is just a in-memory variant which is used to record
the size of the device, and it might be changed before we resize a device,
if the resize operation fails, it will be fallbacked. But some code used it
to update on-disk metadata of the device, it would cause the problem that
on-disk metadata of the devices was not consistent. We should use the other
variant named disk_total_bytes to update the on-disk metadata of device,
because that variant is updated only when the resize operation is successful.
Fix it.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

Truncates and renames are often used to replace old versions of a file
with new versions.  Applications often expect this to be an atomic
replacement, even if they haven't done anything to make sure the new
version is fully on disk.

Btrfs has strict flushing in place to make sure that renaming over an
old file with a new file will fully flush out the new file before
allowing the transaction commit with the rename to complete.

This ordering means the commit code needs to be able to lock file pages,
and there are a few paths in the filesystem where we will try to end a
transaction with the page lock held.  It's rare, but these things can
deadlock.

This patch removes the ordered flushes and switches to a best effort
filemap_flush like ext4 uses. It's not perfect, but it should fix the
deadlocks.
Signed-off-by: NChris Mason <clm@fb.com>

Balance recovery is called when RW mounting or remounting from
RO to RW, it is called to finish roots merging.

When doing balance recovery, relocation root's corresponding
fs root(whose root refs is 0) might be destroyed by cleaner
thread, this will make btrfs fail to mount.

Fix this problem by holding @cleaner_mutex when doing balance
recovery.
Signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

This is a regression from my patch a26e8c9f, we
need to only unlock the block if we were the one who locked it.  Otherwise this
will trip BUG_ON()'s in locking.c  Thanks,

cc: stable@vger.kernel.org
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

Delayed extent operations are triggered during transaction commits.
The goal is to queue up a healthly batch of changes to the extent
allocation tree and run through them in bulk.

This farms them off to async helper threads.  The goal is to have the
bulk of the delayed operations being done in the background, but this is
also important to limit our stack footprint.
Signed-off-by: NChris Mason <clm@fb.com>

This exercises the various parts of the new qgroup accounting code.  We do some
basic stuff and do some things with the shared refs to make sure all that code
works.  I had to add a bunch of infrastructure because I needed to be able to
insert items into a fake tree without having to do all the hard work myself,
hopefully this will be usefull in the future.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

Currently qgroups account for space by intercepting delayed ref updates to fs
trees.  It does this by adding sequence numbers to delayed ref updates so that
it can figure out how the tree looked before the update so we can adjust the
counters properly.  The problem with this is that it does not allow delayed refs
to be merged, so if you say are defragging an extent with 5k snapshots pointing
to it we will thrash the delayed ref lock because we need to go back and
manually merge these things together.  Instead we want to process quota changes
when we know they are going to happen, like when we first allocate an extent, we
free a reference for an extent, we add new references etc.  This patch
accomplishes this by only adding qgroup operations for real ref changes.  We
only modify the sequence number when we need to lookup roots for bytenrs, this
reduces the amount of churn on the sequence number and allows us to merge
delayed refs as we add them most of the time.  This patch encompasses a bunch of
architectural changes

1) qgroup ref operations: instead of tracking qgroup operations through the
delayed refs we simply add new ref operations whenever we notice that we need to
when we've modified the refs themselves.

2) tree mod seq:  we no longer have this separation of major/minor counters.
this makes the sequence number stuff much more sane and we can remove some
locking that was needed to protect the counter.

3) delayed ref seq: we now read the tree mod seq number and use that as our
sequence.  This means each new delayed ref doesn't have it's own unique sequence
number, rather whenever we go to lookup backrefs we inc the sequence number so
we can make sure to keep any new operations from screwing up our world view at
that given point.  This allows us to merge delayed refs during runtime.

With all of these changes the delayed ref stuff is a little saner and the qgroup
accounting stuff no longer goes negative in some cases like it was before.
Thanks,
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

To ease finding bugs during development related to modifying btree leaves
in such a way that it makes its items not sorted by key anymore. Since this
is an expensive check, it's only enabled if CONFIG_BTRFS_FS_CHECK_INTEGRITY
is set, which isn't meant to be enabled for regular users.
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

In close_ctree(), after we have stopped all workers,there maybe still
some read requests(for example readahead) to submit and this *maybe* trigger
an oops that user reported before:

kernel BUG at fs/btrfs/async-thread.c:619!

By hacking codes, i can reproduce this problem with one cpu available.
We fix this potential problem by invalidating all btree inode pages before
stopping all workers.

Thanks to Miao for pointing out this problem.
Signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

In btrfs_create_tree(), if btrfs_insert_root() fails, we should
free root->commit_root.
Reported-by: NAlex Lyakas <alex@zadarastorage.com>
Signed-off-by: NTsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

Current btrfs_orphan_cleanup will also cleanup roots which is already in
fs_info->dead_roots without protection.
This will have conditional race with fs_info->cleaner_kthread.

This patch will use refs in root->root_item to detect roots in
dead_roots and avoid conflicts.
Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

Before applying this patch, the task had to reclaim the metadata space
by itself if the metadata space was not enough. And When the task started
the space reclamation, all the other tasks which wanted to reserve the
metadata space were blocked. At some cases, they would be blocked for
a long time, it made the performance fluctuate wildly.

So we introduce the background metadata space reclamation, when the space
is about to be exhausted, we insert a reclaim work into the workqueue, the
worker of the workqueue helps us to reclaim the reserved space at the
background. By this way, the tasks needn't reclaim the space by themselves at
most cases, and even if the tasks have to reclaim the space or are blocked
for the space reclamation, they will get enough space more quickly.

Here is my test result(Tested by compilebench):
 Memory:	2GB
 CPU:		2Cores * 1CPU
 Partition:	40GB(SSD)

Test command:
 # compilebench -D <mnt> -m

Without this patch:
 intial create total runs 30 avg 54.36 MB/s (user 0.52s sys 2.44s)
 compile total runs 30 avg 123.72 MB/s (user 0.13s sys 1.17s)
 read compiled tree total runs 3 avg 81.15 MB/s (user 0.74s sys 4.89s)
 delete compiled tree total runs 30 avg 5.32 seconds (user 0.35s sys 4.37s)

With this patch:
 intial create total runs 30 avg 59.80 MB/s (user 0.52s sys 2.53s)
 compile total runs 30 avg 151.44 MB/s (user 0.13s sys 1.11s)
 read compiled tree total runs 3 avg 83.25 MB/s (user 0.76s sys 4.91s)
 delete compiled tree total runs 30 avg 5.29 seconds (user 0.34s sys 4.34s)
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

Fix possible memory leaks in the following error handling paths:

read_tree_block()
btrfs_recover_log_trees
btrfs_commit_super()
btrfs_find_orphan_roots()
btrfs_cleanup_fs_roots()
Signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

Lets try this again.  We can deadlock the box if we send on a box and try to
write onto the same fs with the app that is trying to listen to the send pipe.
This is because the writer could get stuck waiting for a transaction commit
which is being blocked by the send.  So fix this by making sure looking at the
commit roots is always going to be consistent.  We do this by keeping track of
which roots need to have their commit roots swapped during commit, and then
taking the commit_root_sem and swapping them all at once.  Then make sure we
take a read lock on the commit_root_sem in cases where we search the commit root
to make sure we're always looking at a consistent view of the commit roots.
Previously we had problems with this because we would swap a fs tree commit root
and then swap the extent tree commit root independently which would cause the
backref walking code to screw up sometimes.  With this patch we no longer
deadlock and pass all the weird send/receive corner cases.  Thanks,
Reportedy-by: NHugo Mills <hugo@carfax.org.uk>
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

So I have an awful exercise script that will run snapshot, balance and
send/receive in parallel.  This sometimes would crash spectacularly and when it
came back up the fs would be completely hosed.  Turns out this is because of a
bad interaction of balance and send/receive.  Send will hold onto its entire
path for the whole send, but its blocks could get relocated out from underneath
it, and because it doesn't old tree locks theres nothing to keep this from
happening.  So it will go to read in a slot with an old transid, and we could
have re-allocated this block for something else and it could have a completely
different transid.  But because we think it is invalid we clear uptodate and
re-read in the block.  If we do this before we actually write out the new block
we could write back stale data to the fs, and boom we're screwed.

Now we definitely need to fix this disconnect between send and balance, but we
really really need to not allow ourselves to accidently read in stale data over
new data.  So make sure we check if the extent buffer is not under io before
clearing uptodate, this will kick back EIO to the caller instead of reading in
stale data and keep us from corrupting the fs.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

We didn't have a lock to protect the access to the delalloc inodes list, that is
we might access a empty delalloc inodes list if someone start flushing delalloc
inodes because the delalloc inodes were moved into a other list temporarily.
Fix it by wrapping the access with a lock.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <jbacik@fb.com>

When we create a snapshot, we just need wait the ordered extents in
the source fs/file root, but because we use the global mutex to protect
this ordered extents list of the source fs/file root to avoid accessing
a empty list, if someone got the mutex to access the ordered extents list
of the other fs/file root, we had to wait.

This patch splits the above global mutex, now every fs/file root has
its own mutex to protect its own list.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <jbacik@fb.com>

If the snapshot creation happened after the nocow write but before the dirty
data flush, we would fail to flush the dirty data because of no space.

So we must keep track of when those nocow write operations start and when they
end, if there are nocow writers, the snapshot creators must wait. In order
to implement this function, I introduce btrfs_{start, end}_nocow_write(),
which is similar to mnt_{want,drop}_write().

These two functions are only used for nocow file write operations.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <jbacik@fb.com>

Since the "_struct" suffix is mainly used for distinguish the differnt
btrfs_work between the original and the newly created one,
there is no need using the suffix since all btrfs_workers are changed
into btrfs_workqueue.

Also this patch fixed some codes whose code style is changed due to the
too long "_struct" suffix.
Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NJosef Bacik <jbacik@fb.com>

Since all the btrfs_worker is replaced with the newly created
btrfs_workqueue, the old codes can be easily remove.
Signed-off-by: NQuwenruo <quwenruo@cn.fujitsu.com>
Tested-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NJosef Bacik <jbacik@fb.com>

Replace the fs_info->qgroup_rescan_worker with the newly created
btrfs_workqueue.
Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NJosef Bacik <jbacik@fb.com>

Replace the fs_info->delayed_workers with the newly created
btrfs_workqueue.
Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NJosef Bacik <jbacik@fb.com>

Replace the fs_info->fixup_workers with the newly created
btrfs_workqueue.
Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NJosef Bacik <jbacik@fb.com>

Replace the fs_info->readahead_workers with the newly created
btrfs_workqueue.
Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NJosef Bacik <jbacik@fb.com>

Replace the fs_info->cache_workers with the newly created
btrfs_workqueue.
Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NJosef Bacik <jbacik@fb.com>

Replace the fs_info->rmw_workers with the newly created
btrfs_workqueue.
Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NJosef Bacik <jbacik@fb.com>

Replace the fs_info->endio_* workqueues with the newly created
btrfs_workqueue.
Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NJosef Bacik <jbacik@fb.com>

Replace the fs_info->submit_workers with the newly created
btrfs_workqueue.
Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NJosef Bacik <jbacik@fb.com>

Much like the fs_info->workers, replace the fs_info->submit_workers
use the same btrfs_workqueue.
Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NJosef Bacik <jbacik@fb.com>