diff options
author | Raghavendra G <rgowdapp@redhat.com> | 2019-05-03 10:14:48 +0530 |
---|---|---|
committer | Shyamsundar Ranganathan <srangana@redhat.com> | 2019-05-08 14:07:56 +0000 |
commit | 09cb7406c28052c4643b2cb6e0ab986331b9576b (patch) | |
tree | 934272985b2b31e14632b20f034d0803861be309 | |
parent | 65505150d665b207e2eb2143599a772c39a648f8 (diff) |
performance/write-behind: remove request from wip list in wb_writev_cbk
There is a race in the way O_DIRECT writes are handled. Assume two
overlapping write requests w1 and w2.
* w1 is issued and is in wb_inode->wip queue as the response is still
pending from bricks. Also wb_request_unref in wb_do_winds is not yet
invoked.
list_for_each_entry_safe (req, tmp, tasks, winds) {
list_del_init (&req->winds);
if (req->op_ret == -1) {
call_unwind_error_keep_stub (req->stub, req->op_ret,
req->op_errno);
} else {
call_resume_keep_stub (req->stub);
}
wb_request_unref (req);
}
* w2 is issued and wb_process_queue is invoked. w2 is not picked up
for winding as w1 is still in wb_inode->wip. w1 is added to todo
list and wb_writev for w2 returns.
* response to w1 is received and invokes wb_request_unref. Assume
wb_request_unref in wb_do_winds (see point 1) is not invoked
yet. Since there is one more refcount, wb_request_unref in
wb_writev_cbk of w1 doesn't remove w1 from wip.
* wb_process_queue is invoked as part of wb_writev_cbk of w1. But, it
fails to wind w2 as w1 is still in wip.
* wb_requet_unref is invoked on w1 as part of wb_do_winds. w1 is
removed from all queues including w1.
* After this point there is no invocation of wb_process_queue unless
new request is issued from application causing w2 to be hung till
the next request.
This bug is similar to bz 1626780 and bz 1379655.
Change-Id: Iaa47437613591699d4c8ad18bc0b32de6affcc31
Signed-off-by: Raghavendra G <rgowdapp@redhat.com>
Fixes: bz#1707198
(cherry picked from commit 6454132342c0b549365d92bcf3572ecd914f7fa8)
-rw-r--r-- | xlators/performance/write-behind/src/write-behind.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/xlators/performance/write-behind/src/write-behind.c b/xlators/performance/write-behind/src/write-behind.c index 60c9148fc30..9a1b9b68a15 100644 --- a/xlators/performance/write-behind/src/write-behind.c +++ b/xlators/performance/write-behind/src/write-behind.c @@ -1816,6 +1816,12 @@ wb_writev_cbk(call_frame_t *frame, void *cookie, xlator_t *this, int32_t op_ret, frame->local = NULL; wb_inode = req->wb_inode; + LOCK(&req->wb_inode->lock); + { + list_del_init(&req->wip); + } + UNLOCK(&req->wb_inode->lock); + wb_request_unref(req); /* requests could be pending while this was in progress */ |