6.4-stable review patch. If anyone has any objections, please let me know.
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From: Alexander Aring aahringo@redhat.com
commit 7c53e847ff5e97f033fdd31f71949807633d506b upstream.
All posix lock ops, for all lockspaces (gfs2 file systems) are sent to userspace (dlm_controld) through a single misc device. The dlm_controld daemon reads the ops from the misc device and sends them to other cluster nodes using separate, per-lockspace cluster api communication channels. The ops for a single lockspace are ordered at this level, so that the results are received in the same sequence that the requests were sent. When the results are sent back to the kernel via the misc device, they are again funneled through the single misc device for all lockspaces. When the dlm code in the kernel processes the results from the misc device, these results will be returned in the same sequence that the requests were sent, on a per-lockspace basis. A recent change in this request/reply matching code missed the "per-lockspace" check (fsid comparison) when matching request and reply, so replies could be incorrectly matched to requests from other lockspaces.
Cc: stable@vger.kernel.org Reported-by: Barry Marson bmarson@redhat.com Fixes: 57e2c2f2d94c ("fs: dlm: fix mismatch of plock results from userspace") Signed-off-by: Alexander Aring aahringo@redhat.com Signed-off-by: David Teigland teigland@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/dlm/plock.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/fs/dlm/plock.c +++ b/fs/dlm/plock.c @@ -456,7 +456,8 @@ static ssize_t dev_write(struct file *fi } } else { list_for_each_entry(iter, &recv_list, list) { - if (!iter->info.wait) { + if (!iter->info.wait && + iter->info.fsid == info.fsid) { op = iter; break; } @@ -468,8 +469,7 @@ static ssize_t dev_write(struct file *fi if (info.wait) WARN_ON(op->info.optype != DLM_PLOCK_OP_LOCK); else - WARN_ON(op->info.fsid != info.fsid || - op->info.number != info.number || + WARN_ON(op->info.number != info.number || op->info.owner != info.owner || op->info.optype != info.optype);