Btrfs: use set_nlink if our i_nlink is 0

We need to inc the nlink of deleted entries when running replay so we can do the
unlink on the fs_root and get everything cleaned up and then have the orphan
cleanup do the right thing.  The problem is inc_nlink complains about this, even
thought it still does the right thing.  So use set_nlink() if our i_nlink is 0
to keep users from seeing the warnings during log replay.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: fix wrong handle at error path of create_snapshot() when the commit fails

There are several bugs at error path of create_snapshot() when the
transaction commitment failed.
- access the freed transaction handler. At the end of the
  transaction commitment, the transaction handler was freed, so we
  should not access it after the transaction commitment.
- we were not aware of the error which happened during the snapshot
  creation if we submitted a async transaction commitment.
- pending snapshot access vs pending snapshot free. when something
  wrong happened after we submitted a async transaction commitment,
  the transaction committer would cleanup the pending snapshots and
  free them. But the snapshot creators were not aware of it, they
  would access the freed pending snapshots.

This patch fixes the above problems by:
- remove the dangerous code that accessed the freed handler
- assign ->error if the error happens during the snapshot creation
- the transaction committer doesn't free the pending snapshots,
  just assigns the error number and evicts them before we unblock
  the transaction.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: fix unclosed transaction handler when the async transaction commitment fails

If the async transaction commitment failed, we need close the
current transaction handler, or the current transaction will be
blocked to commit because of this orphan handler.

We fix the problem by doing sync transaction commitment, that is
to invoke btrfs_commit_transaction().

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: check for NULL pointer in updating reloc roots

Add a check for NULL pointer to avoid invalid reference.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: build up error handling for merge_reloc_roots

We first use btrfs_std_error hook to replace with BUG_ON, and we
also need to cleanup what is left, including reloc roots rbtree
and reloc roots list.
Here we use a helper function to cleanup both rbtree and list, and
since this function can also be used in the balance recover path,
we also make the change as well to keep code simple.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: free all recorded tree blocks on error

We've missed the 'free blocks' part on ENOMEM error.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: do not BUG_ON in prepare_to_reloc

We can bail out from here gracefully instead of a cold BUG_ON.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: do not BUG_ON on aborted situation

Btrfs balance can easily hit BUG_ON in these places, but we want
to it bail out gracefully after we force the whole filesystem to
readonly.  So we use btrfs_std_error hook in place of BUG_ON.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: avoid deadlock on transaction waiting list

Only let one trans handle to wait for other handles, otherwise we
will get ABBA issues.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: allow running defrag in parallel to administrative tasks

Commit 5ac00add added a testnset mutex and code that disallows
running administrative tasks in parallel. It is prevented that
the device add/delete/balance/replace/resize operations are
started in parallel. By mistake, the defragmentation operation
was included in the check for mutually exclusiveness as well.
This is fixed with this commit.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: enforce min_bytes parameter during extent allocation

Commit 24542bf7ea5e4fdfdb5157ff544c093fa4dcb536 changed preallocation of
extents to cap the max size we try to allocate.  It's a valid change,
but the extent reservation code is also used by balance, and that
can't tolerate a smaller extent being allocated.

__btrfs_prealloc_file_range already has a min_size parameter, which is
used by relocation to request a specific extent size.  This commit
adds an extra check to enforce that minimum extent size.

Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Reported-by: Stefan Behrens <sbehrens@giantdisaster.de>
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-next into for-linus-3.9
Btrfs: fix a mismerge in btrfs_balance()

Raid56 merge (merge commit e942f88) had mistakenly removed a call to
__cancel_balance(), which resulted in balance not cleaning up after itself
after a successful finish.  (Cleanup includes switching the state, removing
the balance item and releasing mut_ex_op testnset lock.)  Bring it back.

Reported-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Btrfs: improve the delayed inode throttling

The delayed inode code batches up changes to the btree in hopes of doing
them in bulk.  As the changes build up, processes kick off worker
threads and wait for them to make progress.

The current code kicks off an async work queue item for each delayed
node, which creates a lot of churn.  It also uses a fixed 1 HZ waiting
period for the throttle, which allows us to build a lot of pending
work and can slow down the commit.

This changes us to watch a sequence counter as it is bumped during the
operations.  We kick off fewer work items and have each work item do
more work.

Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs

Pull btrfs fixes from Chris Mason:
 "These are scattered fixes and one performance improvement.  The
  biggest functional change is in how we throttle metadata changes.  The
  new code bumps our average file creation rate up by ~13% in fs_mark,
  and lowers CPU usage.

  Stefan bisected out a regression in our allocation code that made
  balance loop on extents larger than 256MB."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: improve the delayed inode throttling
  Btrfs: fix a mismerge in btrfs_balance()
  Btrfs: enforce min_bytes parameter during extent allocation
  Btrfs: allow running defrag in parallel to administrative tasks
  Btrfs: avoid deadlock on transaction waiting list
  Btrfs: do not BUG_ON on aborted situation
  Btrfs: do not BUG_ON in prepare_to_reloc
  Btrfs: free all recorded tree blocks on error
  Btrfs: build up error handling for merge_reloc_roots
  Btrfs: check for NULL pointer in updating reloc roots
  Btrfs: fix unclosed transaction handler when the async transaction commitment fails
  Btrfs: fix wrong handle at error path of create_snapshot() when the commit fails
  Btrfs: use set_nlink if our i_nlink is 0