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authorAlexander Aring <aahringo@redhat.com>2022-06-22 14:45:19 -0400
committerDavid Teigland <teigland@redhat.com>2022-06-24 11:57:49 -0500
commitf10da927a5e2b0998dca3e5607b39fb8ec007485 (patch)
treefc5e565661a8fea79db35cafbd8dbde46a75096f /fs/dlm/dlm_internal.h
parent3182599f5fff93a30bc094a4a20924eea47fcf42 (diff)
downloadlinux-f10da927a5e2b0998dca3e5607b39fb8ec007485.tar.gz
fs: dlm: add comment about lkb IFL flags
This patch adds comments about the difference between the lower 2 bytes of lkb flags and the 2 upper bytes of the lkb IFL flags. In short the upper 2 bytes will be handled as internal flags whereas the lower 2 bytes are part of the DLM protocol and are used to exchange messages. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
Diffstat (limited to 'fs/dlm/dlm_internal.h')
-rw-r--r--fs/dlm/dlm_internal.h8
1 files changed, 8 insertions, 0 deletions
diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index c03388a3875ca..afec22b1a65fb 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -207,6 +207,14 @@ struct dlm_args {
#define DLM_IFL_TIMEOUT_CANCEL 0x00800000
#define DLM_IFL_DEADLOCK_CANCEL 0x01000000
#define DLM_IFL_STUB_MS 0x02000000 /* magic number for m_flags */
+/* least significant 2 bytes are message changed, they are full transmitted
+ * but at receive side only the 2 bytes LSB will be set.
+ *
+ * Even wireshark dlm dissector does only evaluate the lower bytes and note
+ * that they may not be used on transceiver side, we assume the higher bytes
+ * are for internal use or reserved so long they are not parsed on receiver
+ * side.
+ */
#define DLM_IFL_USER 0x00000001
#define DLM_IFL_ORPHAN 0x00000002