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* btrfs: qgroup: Fix qgroup reserved space underflow by only freeing reserved ↵Qu Wenruo2017-06-291-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ranges [BUG] For the following case, btrfs can underflow qgroup reserved space at an error path: (Page size 4K, function name without "btrfs_" prefix) Task A | Task B ---------------------------------------------------------------------- Buffered_write [0, 2K) | |- check_data_free_space() | | |- qgroup_reserve_data() | | Range aligned to page | | range [0, 4K) <<< | | 4K bytes reserved <<< | |- copy pages to page cache | | Buffered_write [2K, 4K) | |- check_data_free_space() | | |- qgroup_reserved_data() | | Range alinged to page | | range [0, 4K) | | Already reserved by A <<< | | 0 bytes reserved <<< | |- delalloc_reserve_metadata() | | And it *FAILED* (Maybe EQUOTA) | |- free_reserved_data_space() |- qgroup_free_data() Range aligned to page range [0, 4K) Freeing 4K (Special thanks to Chandan for the detailed report and analyse) [CAUSE] Above Task B is freeing reserved data range [0, 4K) which is actually reserved by Task A. And at writeback time, page dirty by Task A will go through writeback routine, which will free 4K reserved data space at file extent insert time, causing the qgroup underflow. [FIX] For btrfs_qgroup_free_data(), add @reserved parameter to only free data ranges reserved by previous btrfs_qgroup_reserve_data(). So in above case, Task B will try to free 0 byte, so no underflow. Reported-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Tested-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: qgroup: Introduce extent changeset for qgroup reserve functionsQu Wenruo2017-06-291-1/+2
| | | | | | | | | | | | | | | | | | | Introduce a new parameter, struct extent_changeset for btrfs_qgroup_reserved_data() and its callers. Such extent_changeset was used in btrfs_qgroup_reserve_data() to record which range it reserved in current reserve, so it can free it in error paths. The reason we need to export it to callers is, at buffered write error path, without knowing what exactly which range we reserved in current allocation, we can free space which is not reserved by us. This will lead to qgroup reserved space underflow. Reviewed-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: qgroup: Cleanup btrfs_qgroup_prepare_account_extents functionQu Wenruo2017-06-291-2/+1
| | | | | | | | | | | | | | | Quite a lot of qgroup corruption happens due to wrong time of calling btrfs_qgroup_prepare_account_extents(). Since the safest time is to call it just before btrfs_qgroup_account_extents(), there is no need to separate these 2 functions. Merging them will make code cleaner and less bug prone. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> [ changelog and comment adjustments ] Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: qgroup: Re-arrange tracepoint timing to co-operate with reserved ↵Qu Wenruo2017-04-181-5/+1
| | | | | | | | | | | | | | | | | | space tracepoint Newly introduced qgroup reserved space trace points are normally nested into several common qgroup operations. While some other trace points are not well placed to co-operate with them, causing confusing output. This patch re-arrange trace_btrfs_qgroup_release_data() and trace_btrfs_qgroup_free_delayed_ref() trace points so they are triggered before reserved space ones. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: qgroup: Add trace point for qgroup reserved spaceQu Wenruo2017-04-181-0/+44
| | | | | | | | | | | | | | | | Introduce the following trace points: qgroup_update_reserve qgroup_meta_reserve These trace points are handy to trace qgroup reserve space related problems. Also export btrfs_qgroup structure, as now we directly pass btrfs_qgroup structure to trace points, so that structure needs to be exported. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: remove unused qgroup members from btrfs_trans_handleDavid Sterba2017-04-181-1/+0
| | | | | | | | | The members have been effectively unused since "Btrfs: rework qgroup accounting" (fcebe4562dec83b3), there's no substitute for assert_qgroups_uptodate so it's removed as well. Reviewed-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: qgroup: Move half of the qgroup accounting time out of commit transQu Wenruo2017-02-171-3/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Just as Filipe pointed out, the most time consuming parts of qgroup are btrfs_qgroup_account_extents() and btrfs_qgroup_prepare_account_extents(). Which both call btrfs_find_all_roots() to get old_roots and new_roots ulist. What makes things worse is, we're calling that expensive btrfs_find_all_roots() at transaction committing time with TRANS_STATE_COMMIT_DOING, which will blocks all incoming transaction. Such behavior is necessary for @new_roots search as current btrfs_find_all_roots() can't do it correctly so we do call it just before switch commit roots. However for @old_roots search, it's not necessary as such search is based on commit_root, so it will always be correct and we can move it out of transaction committing. This patch moves the @old_roots search part out of commit_transaction(), so in theory we can half the time qgroup time consumption at commit_transaction(). But please note that, this won't speedup qgroup overall, the total time consumption is still the same, just reduce the performance stall. Cc: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: allow unlink to exceed subvolume quotaJeff Mahoney2017-02-141-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* btrfs: take an fs_info directly when the root is not used otherwiseJeff Mahoney2016-12-061-1/+1
| | | | | | | | | 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>
* btrfs: Export and move leaf/subtree qgroup helpers to qgroup.cQu Wenruo2016-11-301-0/+23
| | | | | | | | | | | | | | | 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>
* btrfs: qgroup: Rename functions to make it follow reserve,trace,account stepsQu Wenruo2016-11-301-6/+7
| | | | | | | | | | 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>
* btrfs: qgroup: Add comments explaining how btrfs qgroup worksQu Wenruo2016-11-301-0/+28
| | | | | | | | | | | | | | | | | | | | Add explaination how btrfs qgroups work. Qgroup is split into 3 main phrases: 1) Reserve To ensure qgroup doesn't exceed its limit 2) Trace To info qgroup to trace which extent 3) Account Calculate qgroup number change for each traced extent. This should save quite some time for new developers. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: qgroup: Refactor btrfs_qgroup_insert_dirty_extent()Qu Wenruo2016-08-251-4/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* btrfs: waiting on qgroup rescan should not always be interruptibleJeff Mahoney2016-08-251-1/+2
| | | | | | | | | | | | | | | 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>
* btrfs: prefix fsid to all trace eventsJeff Mahoney2016-07-261-4/+5
| | | | | | | | | | | | 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>
* btrfs: qgroup: Check if qgroup reserved space leakedQu Wenruo2015-10-211-0/+1
| | | | | | | | 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>
* btrfs: qgroup: Add new trace point for qgroup data reserveQu Wenruo2015-10-211-0/+8
| | | | | | | | 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>
* btrfs: qgroup: Cleanup old inaccurate facilitiesQu Wenruo2015-10-211-8/+0
| | | | | | | | | | | | | | 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>
* btrfs: qgroup: Introduce new functions to reserve/free metadataQu Wenruo2015-10-211-0/+4
| | | | | | | | Introduce new functions btrfs_qgroup_reserve/free_meta() to reserve/free metadata reserved space. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
* btrfs: delayed_ref: release and free qgroup reserved at proper timingQu Wenruo2015-10-211-1/+17
| | | | | | | | | | | | | | | | | | | | | | | | 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>
* btrfs: qgroup: Introduce functions to release/free qgroup reserve dataQu Wenruo2015-10-211-0/+2
| | | | | | | | | | | | | | | | | | | | | 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>
* btrfs: qgroup: Introduce btrfs_qgroup_reserve_data functionQu Wenruo2015-10-211-0/+2
| | | | | | | | 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>
* btrfs: qgroup: Cleanup the old ref_node-oriented mechanism.Qu Wenruo2015-06-101-49/+0
| | | | | | | Goodbye, the old mechanisim. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
* btrfs: qgroup: Switch self test to extent-oriented qgroup mechanism.Qu Wenruo2015-06-101-0/+5
| | | | | | | | 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>
* btrfs: qgroup: Add new qgroup calculation functionQu Wenruo2015-06-101-0/+2
| | | | | | | | | | | | | | | 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>
* btrfs: qgroup: Add new function to record old_roots.Qu Wenruo2015-06-101-0/+2
| | | | | | | | | | | | | | | 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>
* btrfs: qgroup: Record possible quota-related extent for qgroup.Qu Wenruo2015-06-101-0/+17
| | | | | | | | | 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>
* btrfs: qgroup: do a reservation in a higher level.Dongsheng Yang2015-04-131-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | 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>
* Btrfs: qgroup: Introduce a may_use to account space_info->bytes_may_use.Dongsheng Yang2015-04-131-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: qgroup: cleanup, remove an unsued parameter in btrfs_create_qgroup().Dongsheng Yang2015-04-131-2/+1
| | | | | Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
* btrfs: qgroup: account shared subtrees during snapshot deleteMark Fasheh2014-08-151-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | 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>
* Btrfs: rework qgroup accountingJosef Bacik2014-06-091-0/+107
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>