Filipe Manana wrote on 2015/10/25 14:39 +0000:
On Tue, Oct 13, 2015 at 3:20 AM, Qu Wenruo <quwen...@cn.fujitsu.com> wrote:
Add new function btrfs_add_delayed_qgroup_reserve() function to record
how much space is reserved for that extent.
As btrfs only accounts qgroup at run_delayed_refs() time, so newly
allocated extent should keep the reserved space until then.
So add needed function with related members to do it.
Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com>
---
v2:
None
v3:
None
---
fs/btrfs/delayed-ref.c | 29 +++++++++++++++++++++++++++++
fs/btrfs/delayed-ref.h | 14 ++++++++++++++
2 files changed, 43 insertions(+)
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index ac3e81d..bd9b63b 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -476,6 +476,8 @@ add_delayed_ref_head(struct btrfs_fs_info *fs_info,
INIT_LIST_HEAD(&head_ref->ref_list);
head_ref->processing = 0;
head_ref->total_ref_mod = count_mod;
+ head_ref->qgroup_reserved = 0;
+ head_ref->qgroup_ref_root = 0;
/* Record qgroup extent info if provided */
if (qrecord) {
@@ -746,6 +748,33 @@ int btrfs_add_delayed_data_ref(struct btrfs_fs_info
*fs_info,
return 0;
}
+int btrfs_add_delayed_qgroup_reserve(struct btrfs_fs_info *fs_info,
+ struct btrfs_trans_handle *trans,
+ u64 ref_root, u64 bytenr, u64 num_bytes)
+{
+ struct btrfs_delayed_ref_root *delayed_refs;
+ struct btrfs_delayed_ref_head *ref_head;
+ int ret = 0;
+
+ if (!fs_info->quota_enabled || !is_fstree(ref_root))
+ return 0;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+
+ spin_lock(&delayed_refs->lock);
+ ref_head = find_ref_head(&delayed_refs->href_root, bytenr, 0);
+ if (!ref_head) {
+ ret = -ENOENT;
+ goto out;
+ }
Hi Qu,
So while running btrfs/063, with qgroups enabled (I modified the test
to enable qgroups), ran into this 2 times:
[169125.246506] BTRFS info (device sdc): disk space caching is enabled
[169125.363164] ------------[ cut here ]------------
[169125.365236] WARNING: CPU: 10 PID: 2827 at fs/btrfs/inode.c:2929
btrfs_finish_ordered_io+0x347/0x4eb [btrfs]()
[169125.367702] BTRFS: Transaction aborted (error -2)
[169125.368830] Modules linked in: btrfs dm_flakey dm_mod
crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs
lockd grace fscache sunrpc loop fuse parport_pc parport i2c_piix4
psmouse acpi_cpufreq microcode pcspkr processor evdev i2c_core
serio_raw button ext4 crc16 jbd2 mbcache sd_mod sg sr_mod cdrom
ata_generic virtio_scsi ata_piix libata floppy virtio_pci virtio_ring
scsi_mod e1000 virtio [last unloaded: btrfs]
[169125.376755] CPU: 10 PID: 2827 Comm: kworker/u32:14 Tainted: G
W 4.3.0-rc5-btrfs-next-17+ #1
Hi Filipe,
Although not related to the bug report, I'm a little interested in your
testing kernel.
Are you testing integration-4.4 from Chris repo?
Or 4.3-rc from mainline repo with my qgroup reserve patchset applied?
Although integration-4.4 already merged qgroup reserve patchset, but
it's causing some strange bug like over decrease data
sinfo->bytes_may_use, mainly in generic/127 testcase.
But if qgroup reserve patchset is rebased to integration-4.3 (I did all
my old tests based on that), no generic/127 problem at all.
Thanks,
Qu
[169125.378522] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS rel-1.8.1-0-g4adadbd-20150316_085822-nilsson.home.kraxel.org
04/01/2014
[169125.380916] Workqueue: btrfs-endio-write btrfs_endio_write_helper [btrfs]
[169125.382167] 0000000000000000 ffff88007ef2bc28 ffffffff812566f4
ffff88007ef2bc70
[169125.383643] ffff88007ef2bc60 ffffffff8104d0a6 ffffffffa03cac33
ffff8801f5ca6db0
[169125.385197] ffff8802c6c7ee98 ffff880122bc1000 00000000fffffffe
ffff88007ef2bcc8
[169125.386691] Call Trace:
[169125.387194] [<ffffffff812566f4>] dump_stack+0x4e/0x79
[169125.388205] [<ffffffff8104d0a6>] warn_slowpath_common+0x9f/0xb8
[169125.389386] [<ffffffffa03cac33>] ?
btrfs_finish_ordered_io+0x347/0x4eb [btrfs]
[169125.390837] [<ffffffff8104d107>] warn_slowpath_fmt+0x48/0x50
[169125.391839] [<ffffffffa03d67bb>] ? unpin_extent_cache+0xbe/0xcc [btrfs]
[169125.392973] [<ffffffffa03cac33>]
btrfs_finish_ordered_io+0x347/0x4eb [btrfs]
[169125.395714] [<ffffffff8147c612>] ? _raw_spin_unlock_irqrestore+0x38/0x60
[169125.396888] [<ffffffff81087d0b>] ? trace_hardirqs_off_caller+0x1f/0xb9
[169125.397986] [<ffffffffa03cadec>] finish_ordered_fn+0x15/0x17 [btrfs]
[169125.399122] [<ffffffffa03ec706>] normal_work_helper+0x14c/0x32a [btrfs]
[169125.400300] [<ffffffffa03ec9e6>] btrfs_endio_write_helper+0x12/0x14 [btrfs]
[169125.401450] [<ffffffff81063b23>] process_one_work+0x24a/0x4ac
[169125.402631] [<ffffffff81064285>] worker_thread+0x206/0x2c2
[169125.403622] [<ffffffff8106407f>] ? rescuer_thread+0x2cb/0x2cb
[169125.404693] [<ffffffff8106904d>] kthread+0xef/0xf7
[169125.405727] [<ffffffff81068f5e>] ? kthread_parkme+0x24/0x24
[169125.406808] [<ffffffff8147d10f>] ret_from_fork+0x3f/0x70
[169125.407834] [<ffffffff81068f5e>] ? kthread_parkme+0x24/0x24
[169125.408840] ---[ end trace 6ee4342a5722b119 ]---
[169125.409654] BTRFS: error (device sdc) in
btrfs_finish_ordered_io:2929: errno=-2 No such entry
So what you have here is racy:
btrfs_finish_ordered_io()
joins existing transaction (or starts a new one)
insert_reserved_file_extent()
btrfs_alloc_reserved_file_extent() --> creates delayed ref
******* delayed refs are run, someone called
btrfs_async_run_delayed_refs() from btrfs_end_transaction(), ref head
is removed ******
btrfs_add_delayed_qgroup_reserve() --> does not find delayed ref
head, returns -ENOENT and finish_ordered_io aborts current
transaction...
A very tiny race, but...
thanks
+ WARN_ON(ref_head->qgroup_reserved || ref_head->qgroup_ref_root);
+ ref_head->qgroup_ref_root = ref_root;
+ ref_head->qgroup_reserved = num_bytes;
+out:
+ spin_unlock(&delayed_refs->lock);
+ return ret;
+}
+
int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
struct btrfs_trans_handle *trans,
u64 bytenr, u64 num_bytes,
diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
index 13fb5e6..d4c41e2 100644
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -113,6 +113,17 @@ struct btrfs_delayed_ref_head {
int total_ref_mod;
/*
+ * For qgroup reserved space freeing.
+ *
+ * ref_root and reserved will be recorded after
+ * BTRFS_ADD_DELAYED_EXTENT is called.
+ * And will be used to free reserved qgroup space at
+ * run_delayed_refs() time.
+ */
+ u64 qgroup_ref_root;
+ u64 qgroup_reserved;
+
+ /*
* when a new extent is allocated, it is just reserved in memory
* The actual extent isn't inserted into the extent allocation tree
* until the delayed ref is processed. must_insert_reserved is
@@ -242,6 +253,9 @@ int btrfs_add_delayed_data_ref(struct btrfs_fs_info
*fs_info,
u64 owner, u64 offset, int action,
struct btrfs_delayed_extent_op *extent_op,
int no_quota);
+int btrfs_add_delayed_qgroup_reserve(struct btrfs_fs_info *fs_info,
+ struct btrfs_trans_handle *trans,
+ u64 ref_root, u64 bytenr, u64 num_bytes);
int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
struct btrfs_trans_handle *trans,
u64 bytenr, u64 num_bytes,
--
2.6.1
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