diff options
| author | Ilya Dryomov <idryomov@gmail.com> | 2018-05-21 16:00:29 +0200 |
|---|---|---|
| committer | Ilya Dryomov <idryomov@gmail.com> | 2018-06-04 20:45:58 +0200 |
| commit | 88bc1922c273c95e84a8955e657401f9bc63a80b (patch) | |
| tree | 4f5f0e45685fc055e2ed6643ed62804b088291de /net/ceph | |
| parent | 26df726bcdfacf69335de716e7b78c517bc1df65 (diff) | |
| download | linux-88bc1922c273c95e84a8955e657401f9bc63a80b.tar.bz2 | |
libceph: defer __complete_request() to a workqueue
In the common case, req->r_callback is called by handle_reply() on the
ceph-msgr worker thread without any locks. If handle_reply() fails, it
is called with both osd->lock and osdc->lock. In the map check case,
it is called with just osdc->lock but held for write. Finally, if the
request is aborted because of -ENOSPC or by ceph_osdc_abort_requests(),
it is called directly on the submitter's thread, again with both locks.
req->r_callback on the submitter's thread is relatively new (introduced
in 4.12) and ripe for deadlocks -- e.g. writeback worker thread waiting
on itself:
inode_wait_for_writeback+0x26/0x40
evict+0xb5/0x1a0
iput+0x1d2/0x220
ceph_put_wrbuffer_cap_refs+0xe0/0x2c0 [ceph]
writepages_finish+0x2d3/0x410 [ceph]
__complete_request+0x26/0x60 [libceph]
complete_request+0x2e/0x70 [libceph]
__submit_request+0x256/0x330 [libceph]
submit_request+0x2b/0x30 [libceph]
ceph_osdc_start_request+0x25/0x40 [libceph]
ceph_writepages_start+0xdfe/0x1320 [ceph]
do_writepages+0x1f/0x70
__writeback_single_inode+0x45/0x330
writeback_sb_inodes+0x26a/0x600
__writeback_inodes_wb+0x92/0xc0
wb_writeback+0x274/0x330
wb_workfn+0x2d5/0x3b0
Defer __complete_request() to a workqueue in all failure cases so it's
never on the same thread as ceph_osdc_start_request() and always called
with no locks held.
Link: http://tracker.ceph.com/issues/23978
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Diffstat (limited to 'net/ceph')
| -rw-r--r-- | net/ceph/osd_client.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c index a78f578a2da7..a4c12c37aa90 100644 --- a/net/ceph/osd_client.c +++ b/net/ceph/osd_client.c @@ -2329,6 +2329,14 @@ static void __complete_request(struct ceph_osd_request *req) ceph_osdc_put_request(req); } +static void complete_request_workfn(struct work_struct *work) +{ + struct ceph_osd_request *req = + container_of(work, struct ceph_osd_request, r_complete_work); + + __complete_request(req); +} + /* * This is open-coded in handle_reply(). */ @@ -2338,7 +2346,9 @@ static void complete_request(struct ceph_osd_request *req, int err) req->r_result = err; finish_request(req); - __complete_request(req); + + INIT_WORK(&req->r_complete_work, complete_request_workfn); + queue_work(req->r_osdc->completion_wq, &req->r_complete_work); } static void cancel_map_check(struct ceph_osd_request *req) @@ -5058,6 +5068,10 @@ int ceph_osdc_init(struct ceph_osd_client *osdc, struct ceph_client *client) if (!osdc->notify_wq) goto out_msgpool_reply; + osdc->completion_wq = create_singlethread_workqueue("ceph-completion"); + if (!osdc->completion_wq) + goto out_notify_wq; + schedule_delayed_work(&osdc->timeout_work, osdc->client->options->osd_keepalive_timeout); schedule_delayed_work(&osdc->osds_timeout_work, @@ -5065,6 +5079,8 @@ int ceph_osdc_init(struct ceph_osd_client *osdc, struct ceph_client *client) return 0; +out_notify_wq: + destroy_workqueue(osdc->notify_wq); out_msgpool_reply: ceph_msgpool_destroy(&osdc->msgpool_op_reply); out_msgpool: @@ -5079,6 +5095,7 @@ out: void ceph_osdc_stop(struct ceph_osd_client *osdc) { + destroy_workqueue(osdc->completion_wq); destroy_workqueue(osdc->notify_wq); cancel_delayed_work_sync(&osdc->timeout_work); cancel_delayed_work_sync(&osdc->osds_timeout_work); |