We can embed range_changed to the extent changeset to address following
problems:
- no need to allocate ulist dynamically, we also get rid of the GFP_NOFS
for free
- fix lack of allocation failure checking in btrfs_qgroup_reserve_data
The stack consuption where extent_changeset is used slightly increases:
before: 16
after: 16 - 8 (for pointer) + 32 (sizeof ulist) = 40
Which is bearable.
Reviewed-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Qgroup relations are added/deleted from ioctl, we hold the high level
qgroup lock, no deadlocks or recursion from the allocation possible
here.
Signed-off-by: David Sterba <dsterba@suse.com>
We don't need to use GFP_NOFS here as this is called from ioctls an the
only lock held is the subvol_sem, which is of a high level and protects
creation/renames/deletion and is never held in the writeout paths.
Signed-off-by: David Sterba <dsterba@suse.com>
Once a qgroup limit is exceeded, it's impossible to restore normal
operation to the subvolume without modifying the limit or removing
the subvolume. This is a surprising situation for many users used
to the typical workflow with quotas on other file systems where it's
possible to remove files until the used space is back under the limit.
When we go to unlink a file and start the transaction, we'll hit
the qgroup limit while trying to reserve space for the items we'll
modify while removing the file. We discussed last month how best
to handle this situation and agreed that there is no perfect solution.
The best principle-of-least-surprise solution is to handle it similarly
to how we already handle ENOSPC when unlinking, which is to allow
the operation to succeed with the expectation that it will ultimately
release space under most circumstances.
This patch modifies the transaction start path to select whether to
honor the qgroups limits. btrfs_start_transaction_fallback_global_rsv
is the only caller that skips enforcement. The reservation and tracking
still happens normally -- it just skips the enforcement step.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Goldwyn Rodrigues has exposed and fixed a bug which underflows btrfs
qgroup reserved space, and leads to non-writable fs.
This reminds us that we don't have enough underflow check for qgroup
reserved space.
For underflow case, we should not really underflow the numbers but warn
and keeps qgroup still work.
So add more check on qgroup reserved space and add WARN_ON() and
btrfs_warn() for any underflow case.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Reviewed-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Patches queued up by Filipe:
The most important change is still the fix for the extent tree
corruption that happens due to balance when qgroups are enabled (a
regression introduced in 4.7 by a fix for a regression from the last
qgroups rework). This has been hitting SLE and openSUSE users and QA
very badly, where transactions keep getting aborted when running
delayed references leaving the root filesystem in RO mode and nearly
unusable. There are fixes here that allow us to run xfstests again
with the integrity checker enabled, which has been impossible since 4.8
(apparently I'm the only one running xfstests with the integrity
checker enabled, which is useful to validate dirtied leafs, like
checking if there are keys out of order, etc). The rest are just some
trivial fixes, most of them tagged for stable, and two cleanups.
Signed-off-by: Chris Mason <clm@fb.com>
Now we only use the root parameter to print the root objectid in
a tracepoint. We can use the root parameter from the transaction
handle for that. It's also used to join the transaction with
async commits, so we remove the comment that it's just for checking.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are loads of functions in btrfs that accept a root parameter
but only use it to obtain an fs_info pointer. Let's convert those to
just accept an fs_info pointer directly.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In routines where someptr->fs_info is referenced multiple times, we
introduce a convenience variable. This makes the code considerably
more readable.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We track the node sizes per-root, but they never vary from the values
in the superblock. This patch messes with the 80-column style a bit,
but subsequent patches to factor out root->fs_info into a convenience
variable fix it up again.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Move account_shared_subtree() to qgroup.c and rename it to
btrfs_qgroup_trace_subtree().
Do the same thing for account_leaf_items() and rename it to
btrfs_qgroup_trace_leaf_items().
Since all these functions are only for qgroup, move them to qgroup.c and
export them is more appropriate.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-and-Tested-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Rename btrfs_qgroup_insert_dirty_extent(_nolock) to
btrfs_qgroup_trace_extent(_nolock), according to the new
reserve/trace/account naming schema.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-and-Tested-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The helpers are not meant to be generic, the name is misleading. Convert
them to static inlines for type checking.
Signed-off-by: David Sterba <dsterba@suse.com>
We were setting the qgroup_rescan_running flag to true only after the
rescan worker started (which is a task run by a queue). So if a user
space task starts a rescan and immediately after asks to wait for the
rescan worker to finish, this second call might happen before the rescan
worker task starts running, in which case the rescan wait ioctl returns
immediatley, not waiting for the rescan worker to finish.
This was making the fstest btrfs/022 fail very often.
Fixes: d2c609b834 (btrfs: properly track when rescan worker is running)
Cc: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
For many printks, we want to know which file system issued the message.
This patch converts most pr_* calls to use the btrfs_* versions instead.
In some cases, this means adding plumbing to allow call sites access to
an fs_info pointer.
fs/btrfs/check-integrity.c is left alone for another day.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
CodingStyle chapter 2:
"[...] never break user-visible strings such as printk messages,
because that breaks the ability to grep for them."
This patch unsplits user-visible strings.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have a lot of random ints in btrfs_fs_info that can be put into flags. This
is mostly equivalent with the exception of how we deal with quota going on or
off, now instead we set a flag when we are turning it on or off and deal with
that appropriately, rather than just having a pending state that the current
quota_enabled gets set to. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Refactor btrfs_qgroup_insert_dirty_extent() function, to two functions:
1. btrfs_qgroup_insert_dirty_extent_nolock()
Almost the same with original code.
For delayed_ref usage, which has delayed refs locked.
Change the return value type to int, since caller never needs the
pointer, but only needs to know if they need to free the allocated
memory.
2. btrfs_qgroup_insert_dirty_extent()
The more encapsulated version.
Will do the delayed_refs lock, memory allocation, quota enabled check
and other things.
The original design is to keep exported functions to minimal, but since
more btrfs hacks exposed, like replacing path in balance, we need to
record dirty extents manually, so we have to add such functions.
Also, add comment for both functions, to info developers how to keep
qgroup correct when doing hacks.
Cc: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-and-Tested-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
We wait on qgroup rescan completion in three places: file system
shutdown, the quota disable ioctl, and the rescan wait ioctl. If the
user sends a signal while we're waiting, we continue happily along. This
is expected behavior for the rescan wait ioctl. It's racy in the shutdown
path but mostly works due to other unrelated synchronization points.
In the quota disable path, it Oopses the kernel pretty much immediately.
Cc: <stable@vger.kernel.org> # v4.4+
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
The qgroup_flags field is overloaded such that it reflects the on-disk
status of qgroups and the runtime state. The BTRFS_QGROUP_STATUS_FLAG_RESCAN
flag is used to indicate that a rescan operation is in progress, but if
the file system is unmounted while a rescan is running, the rescan
operation is paused. If the file system is then mounted read-only,
the flag will still be present but the rescan operation will not have
been resumed. When we go to umount, btrfs_qgroup_wait_for_completion
will see the flag and interpret it to mean that the rescan worker is
still running and will wait for a completion that will never come.
This patch uses a separate flag to indicate when the worker is
running. The locking and state surrounding the qgroup rescan worker
needs a lot of attention beyond this patch but this is enough to
avoid a hung umount.
Cc: <stable@vger.kernel.org> # v4.4+
Signed-off-by; Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
btrfs_trans_handle->root is documented as for use for confirming
that the root passed in to start the transaction is the same as the
one ending it. It's used in several places when an fs_info pointer
is needed, so let's just add an fs_info pointer directly. Eventually,
the root pointer can be removed.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we have a dummy fs_info associated with each test that
uses a root, we don't need the DUMMY_ROOT bit anymore. This lets
us make choices without needing an actual root like in e.g.
btrfs_find_create_tree_block.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When using trace events to debug a problem, it's impossible to determine
which file system generated a particular event. This patch adds a
macro to prefix standard information to the head of a trace event.
The extent_state alloc/free events are all that's left without an
fs_info available.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This patch adds tracepoints to the qgroup code on both the reporting side
(insert_dirty_extents) and the accounting side. Taken together it allows us
to see what qgroup operations have happened, and what their result was.
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
create_pending_snapshot() will go readonly on _any_ error return from
btrfs_qgroup_inherit(). If qgroups are enabled, a user can crash their fs by
just making a snapshot and asking it to inherit from an invalid qgroup. For
example:
$ btrfs sub snap -i 1/10 /btrfs/ /btrfs/foo
Will cause a transaction abort.
Fix this by only throwing errors in btrfs_qgroup_inherit() when we know
going readonly is acceptable.
The following xfstests test case reproduces this bug:
seq=`basename $0`
seqres=$RESULT_DIR/$seq
echo "QA output created by $seq"
here=`pwd`
tmp=/tmp/$$
status=1 # failure is the default!
trap "_cleanup; exit \$status" 0 1 2 3 15
_cleanup()
{
cd /
rm -f $tmp.*
}
# get standard environment, filters and checks
. ./common/rc
. ./common/filter
# remove previous $seqres.full before test
rm -f $seqres.full
# real QA test starts here
_supported_fs btrfs
_supported_os Linux
_require_scratch
rm -f $seqres.full
_scratch_mkfs
_scratch_mount
_run_btrfs_util_prog quota enable $SCRATCH_MNT
# The qgroup '1/10' does not exist and should be silently ignored
_run_btrfs_util_prog subvolume snapshot -i 1/10 $SCRATCH_MNT $SCRATCH_MNT/snap1
_scratch_unmount
echo "Silence is golden"
status=0
exit
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Reviewed-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Commit 0ed4792 ('btrfs: qgroup: Switch to new extent-oriented qgroup
mechanism.') removed our qgroup accounting during
btrfs_drop_snapshot(). Predictably, this results in qgroup numbers
going bad shortly after a snapshot is removed.
Fix this by adding a dirty extent record when we encounter extents during
our shared subtree walk. This effectively restores the functionality we had
with the original shared subtree walking code in 1152651 (btrfs: qgroup:
account shared subtrees during snapshot delete).
The idea with the original patch (and this one) is that shared subtrees can
get skipped during drop_snapshot. The shared subtree walk then allows us a
chance to visit those extents and add them to the qgroup work for later
processing. This ultimately makes the accounting for drop snapshot work.
The new qgroup code nicely handles all the other extents during the tree
walk via the ref dec/inc functions so we don't have to add actions beyond
what we had originally.
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Chris Mason <clm@fb.com>
There's a race condition that leads to a NULL pointer dereference if you
disable quotas while a quota rescan is running. To fix this, we just need
to wait for the quota rescan worker to actually exit before tearing down
the quota structures.
Signed-off-by: Justin Maggard <jmaggard@netgear.com>
Signed-off-by: Chris Mason <clm@fb.com>
We were initializing the completion (fs_info->qgroup_rescan_completion)
object after releasing the qgroup rescan lock, which gives a small time
window for a rescan waiter to not actually wait for the rescan worker
to finish. Example:
CPU 1 CPU 2
fs_info->qgroup_rescan_completion->done is 0
btrfs_qgroup_rescan_worker()
complete_all(&fs_info->qgroup_rescan_completion)
sets fs_info->qgroup_rescan_completion->done
to UINT_MAX / 2
... do some other stuff ....
qgroup_rescan_init()
mutex_lock(&fs_info->qgroup_rescan_lock)
set flag BTRFS_QGROUP_STATUS_FLAG_RESCAN
in fs_info->qgroup_flags
mutex_unlock(&fs_info->qgroup_rescan_lock)
btrfs_qgroup_wait_for_completion()
mutex_lock(&fs_info->qgroup_rescan_lock)
sees flag BTRFS_QGROUP_STATUS_FLAG_RESCAN
in fs_info->qgroup_flags
mutex_unlock(&fs_info->qgroup_rescan_lock)
wait_for_completion_interruptible(
&fs_info->qgroup_rescan_completion)
fs_info->qgroup_rescan_completion->done
is > 0 so it returns immediately
init_completion(&fs_info->qgroup_rescan_completion)
sets fs_info->qgroup_rescan_completion->done to 0
So fix this by initializing the completion object while holding the mutex
fs_info->qgroup_rescan_lock.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
I was hitting a consistent NULL pointer dereference during shutdown that
showed the trace running through end_workqueue_bio(). I traced it back to
the endio_meta_workers workqueue being poked after it had already been
destroyed.
Eventually I found that the root cause was a qgroup rescan that was still
in progress while we were stopping all the btrfs workers.
Currently we explicitly pause balance and scrub operations in
close_ctree(), but we do nothing to stop the qgroup rescan. We should
probably be doing the same for qgroup rescan, but that's a much larger
change. This small change is good enough to allow me to unmount without
crashing.
Signed-off-by: Justin Maggard <jmaggard@netgear.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
When rebasing my patchset, I forgot to pick up a cleanup patch to remove
old hotfix in 4.2 release.
Witouth the cleanup, it will screw up new qgroup reserve framework and
always cause minus reserved number.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Ancient qgroup code call memcpy() on a extent buffer and use it for leaf
iteration.
As extent buffer contains lock, pointers to pages, it's never sane to do
such copy.
The following bug may be caused by this insane operation:
[92098.841309] general protection fault: 0000 [#1] SMP
[92098.841338] Modules linked in: ...
[92098.841814] CPU: 1 PID: 24655 Comm: kworker/u4:12 Not tainted
4.3.0-rc1 #1
[92098.841868] Workqueue: btrfs-qgroup-rescan btrfs_qgroup_rescan_helper
[btrfs]
[92098.842261] Call Trace:
[92098.842277] [<ffffffffc035a5d8>] ? read_extent_buffer+0xb8/0x110
[btrfs]
[92098.842304] [<ffffffffc0396d00>] ? btrfs_find_all_roots+0x60/0x70
[btrfs]
[92098.842329] [<ffffffffc039af3d>]
btrfs_qgroup_rescan_worker+0x28d/0x5a0 [btrfs]
Where btrfs_qgroup_rescan_worker+0x28d is btrfs_disk_key_to_cpu(),
called in reading key from the copied extent_buffer.
This patch will use btrfs_clone_extent_buffer() to a better copy of
extent buffer to deal such case.
Reported-by: Stephane Lesimple <stephane_btrfs@lesimple.fr>
Suggested-by: Filipe Manana <fdmanana@kernel.org>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Add check at btrfs_destroy_inode() time to detect qgroup reserved space
leak.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Now each qgroup reserve for data will has its ftrace event for better
debugging.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Cleanup the old facilities which use old btrfs_qgroup_reserve() function
call, replace them with the newer version, and remove the "__" prefix in
them.
Also, make btrfs_qgroup_reserve/free() functions private, as they are
now only used inside qgroup codes.
Now, the whole btrfs qgroup is swithed to use the new reserve facilities.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Qgroup reserved space needs to be released from inode dirty map and get
freed at different timing:
1) Release when the metadata is written into tree
After corresponding metadata is written into tree, any newer write will
be COWed(don't include NOCOW case yet).
So we must release its range from inode dirty range map, or we will
forget to reserve needed range, causing accounting exceeding the limit.
2) Free reserved bytes when delayed ref is run
When delayed refs are run, qgroup accounting will follow soon and turn
the reserved bytes into rfer/excl numbers.
As run_delayed_refs and qgroup accounting are all done at
commit_transaction() time, we are safe to free reserved space in
run_delayed_ref time().
With these timing to release/free reserved space, we should be able to
resolve the long existing qgroup reserve space leak problem.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
space
Introduce functions btrfs_qgroup_release/free_data() to release/free
reserved data range.
Release means, just remove the data range from io_tree, but doesn't
free the reserved space.
This is for normal buffered write case, when data is written into disc
and its metadata is added into tree, its reserved space should still be
kept until commit_trans().
So in that case, we only release dirty range, but keep the reserved
space recorded some other place until commit_tran().
Free means not only remove data range, but also free reserved space.
This is used for case for cleanup and invalidate page.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Introduce a new function, btrfs_qgroup_reserve_data(), which will use
io_tree to accurate qgroup reserve, to avoid reserved space leaking.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
During the change to new btrfs extent-oriented qgroup implement, due to
it doesn't use the old __qgroup_excl_accounting() for exclusive extent,
it didn't free the reserved bytes.
The bug will cause limit function go crazy as the reserved space is
never freed, increasing limit will have no effect and still cause
EQOUT.
The fix is easy, just free reserved bytes for newly created exclusive
extent as what it does before.
Reported-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Yang Dongsheng <yangds.fnst@cn.fujitsu.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Currently, we can only set a limitation on a qgroup, but we
can not clear it.
This patch provide a choice to user to clear a limitation on
qgroup by passing a value of CLEAR_VALUE(-1) to kernel.
Reported-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Tested-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
This is used by later qgroup fix patches for snapshot.
As current snapshot accounting is done by btrfs_qgroup_inherit(), but
new extent oriented quota mechanism will account extent from
btrfs_copy_root() and other snapshot things, causing wrong result.
So add this ability to handle snapshot accounting.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Since the self test transaction don't have delayed_ref_roots, so use
find_all_roots() and export btrfs_qgroup_account_extent() to simulate it
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Switch rescan to use the new new extent oriented mechanism.
As rescan is also based on extent, new mechanism is just a perfect match
for rescan.
With re-designed internal functions, rescan is quite easy, just call
btrfs_find_all_roots() and then btrfs_qgroup_account_one_extent().
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
btrfs_qgroup_account_extents().
The new btrfs_qgroup_account_extents() function should be called in
btrfs_commit_transaction() and it will update all the qgroup according
to delayed_ref_root->dirty_extent_root.
The new function can handle both normal operation during
commit_transaction() or in rescan in a unified method with clearer
logic.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Add function btrfs_qgroup_prepare_account_extents() to get old_roots
which are needed for qgroup.
We do it in commit_transaction() and before switch_roots(), and only
search commit_root, so it gives a quite accurate view for previous
transaction.
With old_roots from previous transaction, we can use it to do accurate
account with current transaction.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Add hook in add_delayed_ref_head() to record quota-related extent record
into delayed_ref_root->dirty_extent_record rb-tree for later qgroup
accounting.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Add function qgroup_update_counters(), which will update related
qgroups' rfer/excl according to old/new_roots.
This is one of the two core functions for the new qgroup implement.
This is based on btrfs_adjust_coutners() but with clearer logic and
comment.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
This function is used to update refcnt for qgroups.
And is one of the two core functions used in the new qgroup implement.
This is based on the old update_old/new_refcnt, but provides a unified
logic and behavior.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Use inline functions to do such things, to improve readability.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Acked-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
Commit 9c8b35b1ba ("btrfs: quota: Automatically update related qgroups or
mark INCONSISTENT flags when assigning/deleting a qgroup relations.")
introduced the allocation of a temporary ulist in function
btrfs_add_qgroup_relation() and added the corresponding cleanup to the out
path. However, the allocation was introduced before the src/dst level check
that directly returns. Fix the possible leakage of the ulist by moving the
allocation after the input validation. Detected by Coverity CID 1295988.
Signed-off-by: Christian Engelmayer <cengelma@gmx.at>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
Operation like qgroups assigning/deleting qgroup relations will mostly
cause qgroup data inconsistent, since it needs to do the full rescan to
determine whether shared extents are exclusive or still shared in
parent qgroups.
But there are some exceptions, like qgroup with only exclusive extents
(qgroup->excl == qgroup->rfer), in that case, we only needs to
modify all its parents' excl and rfer.
So this patch adds a quick path for such qgroup in qgroup
assign/remove routine, and if quick path failed, the qgroup status will
be marked INCONSISTENT, and return 1 to info user-land.
BTW since the quick path is much the same of qgroup_excl_accounting(),
so move the core of it to __qgroup_excl_accounting() and reuse it.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
we forgot to clear STATUS_FLAG_ON in quota_disable(), it
will cause a problem shown as below:
# mount /dev/sdc /mnt
# btrfs quota enable /mnt
# btrfs quota disable /mnt
# btrfs quota rescan /mnt
quota rescan started <--- expecting it fail here.
# echo $?
0
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Update qgroup status when rescan is done.
Before this patch, status item is not updated on rescan finish, which
causing the RESCAN and INCONSISTENT flags never cleared.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Old qgroup_rescan_leaf() comment indicates ret == 2 as complete and
cleared INCONSISTENT flag.
This is not true since it will never return 2, and inside it no codes
will clear INCONSISTENT flag.
The flag clearance is done in btrfs_qgroup_rescan_work().
This caused the bug that INCONSISTENT flag is never cleared.
So change the comment and fix the dead judgment.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Although we have qgroup level check in btrfs-progs, it's not enough
since other programe may still call ioctl directly not using
btrfs-progs. For example, systemd.
But it's btrfs-progs to be blame since we don't provide a
full-function(like subvolume create things) btrfs library with enough
check, and only rely on kernel ioctl.
So Add level checks in kernel too.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
When a qgroup has parents but no child, it should be removable in
Theory I think. But currently, we can not remove it when it has
either parent or child.
Example:
# btrfs quota enable /mnt
# btrfs qgroup create 1/0 /mnt
# btrfs qgroup create 2/0 /mnt
# btrfs qgroup assign 1/0 2/0 /mnt
# btrfs qgroup show -pcre /mnt
qgroupid rfer excl max_rfer max_excl parent child
-------- ---- ---- -------- -------- ------ -----
0/5 16384 16384 0 0 --- ---
1/0 0 0 0 0 2/0 ---
2/0 0 0 0 0 --- 1/0
At this time, there is no subvol or qgroup depending on it.
Just a qgroup 2/0 is its parent, but 2/0 can work well without
1/0. So I think 1/0 should be removalbe. But:
# btrfs qgroup destroy 1/0 /mnt
ERROR: unable to destroy quota group: Device or resource busy
This patch remove the check of qgroup->parent in removing it,
then we can remove a qgroup when it has a parent.
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
When we create a subvol inheriting a qgroup, we need to check the level
of them. Otherwise, there is a chance a qgroup can inherit another qgroup
at the same level.
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
There are two problems in qgroup:
a). The PAGE_CACHE is 4K, even when we are writing a data of 1K,
qgroup will reserve a 4K size. It will cause the last 3K in a qgroup
is not available to user.
b). When user is writing a inline data, qgroup will not reserve it,
it means this is a window we can exceed the limit of a qgroup.
The main idea of this patch is reserving the data size of write_bytes
rather than the reserve_bytes. It means qgroup will not care about
the data size btrfs will reserve for user, but only care about the
data size user is going to write. Then reserve it when user want to
write and release it in transaction committed.
In this way, qgroup can be released from the complex procedure in
btrfs and only do the reserve when user want to write and account
when the data is written in commit_transaction().
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Currently, for pre_alloc or delay_alloc, the bytes will be accounted
in space_info by the three guys.
space_info->bytes_may_use --- space_info->reserved --- space_info->used.
But on the other hand, in qgroup, there are only two counters to account the
bytes, qgroup->reserved and qgroup->excl. And qg->reserved accounts
bytes in space_info->bytes_may_use and qg->excl accounts bytes in
space_info->used. So the bytes in space_info->reserved is not accounted
in qgroup. If so, there is a window we can exceed the quota limit when
bytes is in space_info->reserved.
Example:
# btrfs quota enable /mnt
# btrfs qgroup limit -e 10M /mnt
# for((i=0;i<20;i++));do fallocate -l 1M /mnt/data$i; done
# sync
# btrfs qgroup show -pcre /mnt
qgroupid rfer excl max_rfer max_excl parent child
-------- ---- ---- -------- -------- ------ -----
0/5 20987904 20987904 0 10485760 --- ---
qg->excl is 20987904 larger than max_excl 10485760.
This patch introduce a new counter named may_use to qgroup, then
there are three counters in qgroup to account bytes in space_info
as below.
space_info->bytes_may_use --- space_info->reserved --- space_info->used.
qgroup->may_use --- qgroup->reserved --- qgroup->excl
With this patch applied:
# btrfs quota enable /mnt
# btrfs qgroup limit -e 10M /mnt
# for((i=0;i<20;i++));do fallocate -l 1M /mnt/data$i; done
fallocate: /mnt/data9: fallocate failed: Disk quota exceeded
fallocate: /mnt/data10: fallocate failed: Disk quota exceeded
fallocate: /mnt/data11: fallocate failed: Disk quota exceeded
fallocate: /mnt/data12: fallocate failed: Disk quota exceeded
fallocate: /mnt/data13: fallocate failed: Disk quota exceeded
fallocate: /mnt/data14: fallocate failed: Disk quota exceeded
fallocate: /mnt/data15: fallocate failed: Disk quota exceeded
fallocate: /mnt/data16: fallocate failed: Disk quota exceeded
fallocate: /mnt/data17: fallocate failed: Disk quota exceeded
fallocate: /mnt/data18: fallocate failed: Disk quota exceeded
fallocate: /mnt/data19: fallocate failed: Disk quota exceeded
# sync
# btrfs qgroup show -pcre /mnt
qgroupid rfer excl max_rfer max_excl parent child
-------- ---- ---- -------- -------- ------ -----
0/5 9453568 9453568 0 10485760 --- ---
Reported-by: Cyril SCETBON <cyril.scetbon@free.fr>
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
btrfs_limit_group use arg limit to override the old qgroup_limit of
corresponding qgroup. However, we should override part of old qgroup_limit
according to the bit which has been set in arg limit.
Signed-off-by: Fan Chengniang <fancn.fnst@cn.fujitsu.com>
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
When we commit_transaction(), qgroups in btree should be updated.
But, limit info is not considered currently. It will cause a problem
when a qgroup of a snapshot inherit the limit info from srcqgroup,
then there is an inconsistency.
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Cleanup: Change the parameter of update_qgroup_limit_item() to the family of
update_qgroup_xxx_item().
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
When we call btrfs_qgroup_inherit() with BTRFS_QGROUP_INHERIT_SET_LIMITS,
btrfs will update the limit info of qgroup in btree but forget to update
the qgroup in rbtree at the same time. It obviousely will cause an inconsistency.
This patch fix it by updating the rbtree at the same time.
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Currently, when we snapshot a subvol, snapshot will not copy the limits
from srcqgroup.
This patch make the qgroup in snapshot inherit the limit info when create
a snapshot.
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
After looking at Liu Bo's recent patch (titled
"Btrfs: fix comp_oper to get right order") I realized the search made by
qgroup_oper_exists() was buggy because its rbtree navigation comparison
function, comp_oper_exist(), only looks at the fields bytenr and ref_root
of a tree node, ignoring the seq field completely. This was wrong because
when we insert a node into the rbtree we use comp_oper(), which takes a
decision based first on bytenr, then on seq and then on the ref_root field.
That means qgroup_oper_exists() could miss the fact that at least one
operation with given bytenr and ref_root exists.
Consider the following simple example of a 3 nodes qgroup operations
rbtree (created using comp_oper before this patch), where each node's key
is a tuple with the shape (bytenr, seq, ref_root, op):
[ (4096, 2, 20, op X) ]
/ \
/ \
[ (4096, 1, 5, op Y) ] [ (4096, 3, 10, op Z) ]
qgroup_oper_exists() when called to search for an existing operation for
bytenr 4096 and ref root 10 wouldn't find anything because it would go to
the left subtree instead of the right subtree, since comp_oper_exits()
ignores the seq field completely.
Fix this by changing the insertion navigation function to use the ref_root
field right after using the bytenr field and before using the seq field,
so that qgroup_oper_exists() / comp_oper_exist() work as expected.
This patch applies on top of the patch mentioned above from Liu.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Case (oper1->seq > oper2->seq) should differ with case (oper1->seq < oper2->seq).
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Using {} as initializer for struct seq_elem does not properly initialize
the list_head member, but it currently works because it gets set through
btrfs_get_tree_mod_seq if 'seq' is 0.
Signed-off-by: David Sterba <dsterba@suse.cz>
This is the 3rd independent patch of a larger project to cleanup btrfs's
internal usage of btrfs_root. Many functions take btrfs_root only to
grab the fs_info struct.
By requiring a root these functions cause programmer overhead. That
these functions can accept any valid root is not obvious until
inspection.
This patch reduces the specificity of such functions to accept the
fs_info directly.
These patches can be applied independently and thus are not being
submitted as a patch series. There should be about 26 patches by the
project's completion. Each patch will cleanup between 1 and 34 functions
apiece. Each patch covers a single file's functions.
This patch affects the following function(s):
1) csum_tree_block
2) csum_dirty_buffer
3) check_tree_block_fsid
4) btrfs_find_tree_block
5) clean_tree_block
Signed-off-by: Daniel Dressler <danieru.dressler@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
In function qgroup_excl_accounting(), we need to WARN when
qg->excl is less than what we want to free, same to child
and parents. But currently, for parent qgroup, the WARN_ON()
is located after freeing qg->excl. It will WARN out even we
free it normally.
This patch move this WARN_ON() before freeing qg->excl.
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Reviewed-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
btrfs_drop_snapshot() leaves subvolume qgroup items on disk after
completion. This can cause problems with snapshot creation. If a new
snapshot tries to claim the deleted subvolumes id, btrfs will get -EEXIST
from add_qgroup_item() and go read-only. The following commands will
reproduce this problem (assume btrfs is on /dev/sda and is mounted at
/btrfs)
mkfs.btrfs -f /dev/sda
mount -t btrfs /dev/sda /btrfs/
btrfs quota enable /btrfs/
btrfs su sna /btrfs/ /btrfs/snap
btrfs su de /btrfs/snap
sleep 45
umount /btrfs/
mount -t btrfs /dev/sda /btrfs/
We can fix this by catching -EEXIST in add_qgroup_item() and
initializing the existing items. We have the problem of orphaned
relation items being on disk from an old snapshot but that is outside
the scope of this patch.
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Chris Mason <clm@fb.com>
We want this to debug qgroup changes on live systems.
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris 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: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris 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: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <clm@fb.com>
Coverity pointed this out; in the newly added
qgroup_subtree_accounting(), if btrfs_find_all_roots()
returns an error, we leak at least the parents pointer,
and possibly the roots pointer, depending on what failure
occurs.
If btrfs_find_all_roots() returns an error, we need to
free up all allocations before we return. "roots" is
initialized to NULL, so it should be safe to free
it unconditionally (ulist_free() handles that case).
Cc: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Chris Mason <clm@fb.com>
ulist_add() can return '1' on sucess, which qgroup_subtree_accounting()
doesn't take into account. As a result, that value can be bubbled up to
callers, causing an error to be printed. Fix this by only returning the
value of ulist_add() when it indicates an error.
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Chris Mason <clm@fb.com>
During its tree walk, btrfs_drop_snapshot() will skip any shared
subtrees it encounters. This is incorrect when we have qgroups
turned on as those subtrees need to have their contents
accounted. In particular, the case we're concerned with is when
removing our snapshot root leaves the subtree with only one root
reference.
In those cases we need to find the last remaining root and add
each extent in the subtree to the corresponding qgroup exclusive
counts.
This patch implements the shared subtree walk and a new qgroup
operation, BTRFS_QGROUP_OPER_SUB_SUBTREE. When an operation of
this type is encountered during qgroup accounting, we search for
any root references to that extent and in the case that we find
only one reference left, we go ahead and do the math on it's
exclusive counts.
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
If tmp = ulist_alloc(GFP_NOFS) fails, we return without
freeing the previously allocated qgroups = ulist_alloc(GFP_NOFS)
and cause a memory leak.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Chris 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: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris 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: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@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: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Replace the fs_info->qgroup_rescan_worker with the newly created
btrfs_workqueue.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Could have sworn I fixed this before but apparently not. This makes us pass
btrfs/022 with skinny metadata enabled. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Convert all applicable cases of printk and pr_* to the btrfs_* macros.
Fix all uses of the BTRFS prefix.
Signed-off-by: Frank Holton <fholton@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Use otherwise unused local variables slot in update_qgroup_limit_item and
in update_qgroup_info_item, and remove unused variable ins from
btrfs_qgroup_account_ref.
Signed-off-by: Valentina Giusti <valentina.giusti@microon.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <clm@fb.com>
u64 is "unsigned long long" on all architectures now, so there's no need to
cast it when formatting it using the "ll" length modifier.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
We have checked 'quota_root' with qgroup_ioctl_lock held before,So
here the check is reduplicate, remove it.
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Reviewed-by: Arne Jansen <sensille@gmx.net>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
