In ceph_sync_write(), if a safe callback is supplied with a request,
and an error is returned by ceph_osdc_wait_request(), a block of
code is executed to remove the request from the unsafe writes list
and drop references to capabilities acquired just prior to a call to
ceph_osdc_wait_request().
The only function used for this callback is sync_write_commit(),
and it does *exactly* what that block of error handling code does.
Now in ceph_osdc_wait_request(), if an error occurs (due to an
interupt during a wait_for_completion_interruptible() call),
complete_request() gets called, and that calls the request's
safe_callback method if it's defined.
So this means that this cleanup activity gets called twice in this
case, which is erroneous (and in fact leads to a crash).
Fix this by just letting the osd client handle the cleanup in
the event of an interrupt.
This resolves one problem mentioned in:
http://tracker.ceph.com/issues/4706
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yan, Zheng <zheng.z.yan@intel.com>
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