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authorDavid Teigland <teigland@redhat.com>2007-04-19 11:30:41 -0400
committerSteven Whitehouse <swhiteho@redhat.com>2007-05-01 04:11:36 -0400
commit7d3c1feb80913ba4253c3517d48b9b3741c44fc9 (patch)
treee52a741e4148c7193617e17d34dc68dc735e0392 /fs/dlm
parent5f8820960cf4fb621483d4a37c24939ad831bfe7 (diff)
[DLM] fix mode munging
There are flags to enable two specialized features in the dlm: 1. CONVDEADLK causes the dlm to resolve conversion deadlocks internally by changing the granted mode of locks to NL. 2. ALTPR/ALTCW cause the dlm to change the requested mode of locks to PR or CW to grant them if the normal requested mode can't be granted. GFS direct i/o exercises both of these features, especially when mixed with buffered i/o. The dlm has problems with them. The first problem is on the master node. If it demotes a lock as a part of converting it, the actual step of converting the lock isn't being done after the demotion, the lock is just left sitting on the granted queue with a granted mode of NL. I think the mistaken assumption was that the call to grant_pending_locks() would grant it, but that function naturally doesn't look at locks on the granted queue. The second problem is on the process node. If the master either demotes or gives an altmode, the munging of the gr/rq modes is never done in the process copy of the lock, leaving the master/process copies out of sync. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Diffstat (limited to 'fs/dlm')
-rw-r--r--fs/dlm/lock.c82
1 files changed, 80 insertions, 2 deletions
diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index eac54d230fdc..d8d6e729f96b 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -224,6 +224,16 @@ static inline int is_demoted(struct dlm_lkb *lkb)
224 return (lkb->lkb_sbflags & DLM_SBF_DEMOTED); 224 return (lkb->lkb_sbflags & DLM_SBF_DEMOTED);
225} 225}
226 226
227static inline int is_altmode(struct dlm_lkb *lkb)
228{
229 return (lkb->lkb_sbflags & DLM_SBF_ALTMODE);
230}
231
232static inline int is_granted(struct dlm_lkb *lkb)
233{
234 return (lkb->lkb_status == DLM_LKSTS_GRANTED);
235}
236
227static inline int is_remote(struct dlm_rsb *r) 237static inline int is_remote(struct dlm_rsb *r)
228{ 238{
229 DLM_ASSERT(r->res_nodeid >= 0, dlm_print_rsb(r);); 239 DLM_ASSERT(r->res_nodeid >= 0, dlm_print_rsb(r););
@@ -1191,6 +1201,50 @@ static void grant_lock_pending(struct dlm_rsb *r, struct dlm_lkb *lkb)
1191 queue_cast(r, lkb, 0); 1201 queue_cast(r, lkb, 0);
1192} 1202}
1193 1203
1204/* The special CONVDEADLK, ALTPR and ALTCW flags allow the master to
1205 change the granted/requested modes. We're munging things accordingly in
1206 the process copy.
1207 CONVDEADLK: our grmode may have been forced down to NL to resolve a
1208 conversion deadlock
1209 ALTPR/ALTCW: our rqmode may have been changed to PR or CW to become
1210 compatible with other granted locks */
1211
1212static void munge_demoted(struct dlm_lkb *lkb, struct dlm_message *ms)
1213{
1214 if (ms->m_type != DLM_MSG_CONVERT_REPLY) {
1215 log_print("munge_demoted %x invalid reply type %d",
1216 lkb->lkb_id, ms->m_type);
1217 return;
1218 }
1219
1220 if (lkb->lkb_rqmode == DLM_LOCK_IV || lkb->lkb_grmode == DLM_LOCK_IV) {
1221 log_print("munge_demoted %x invalid modes gr %d rq %d",
1222 lkb->lkb_id, lkb->lkb_grmode, lkb->lkb_rqmode);
1223 return;
1224 }
1225
1226 lkb->lkb_grmode = DLM_LOCK_NL;
1227}
1228
1229static void munge_altmode(struct dlm_lkb *lkb, struct dlm_message *ms)
1230{
1231 if (ms->m_type != DLM_MSG_REQUEST_REPLY &&
1232 ms->m_type != DLM_MSG_GRANT) {
1233 log_print("munge_altmode %x invalid reply type %d",
1234 lkb->lkb_id, ms->m_type);
1235 return;
1236 }
1237
1238 if (lkb->lkb_exflags & DLM_LKF_ALTPR)
1239 lkb->lkb_rqmode = DLM_LOCK_PR;
1240 else if (lkb->lkb_exflags & DLM_LKF_ALTCW)
1241 lkb->lkb_rqmode = DLM_LOCK_CW;
1242 else {
1243 log_print("munge_altmode invalid exflags %x", lkb->lkb_exflags);
1244 dlm_print_lkb(lkb);
1245 }
1246}
1247
1194static inline int first_in_list(struct dlm_lkb *lkb, struct list_head *head) 1248static inline int first_in_list(struct dlm_lkb *lkb, struct list_head *head)
1195{ 1249{
1196 struct dlm_lkb *first = list_entry(head->next, struct dlm_lkb, 1250 struct dlm_lkb *first = list_entry(head->next, struct dlm_lkb,
@@ -1965,9 +2019,24 @@ static int do_convert(struct dlm_rsb *r, struct dlm_lkb *lkb)
1965 goto out; 2019 goto out;
1966 } 2020 }
1967 2021
1968 if (can_be_queued(lkb)) { 2022 /* is_demoted() means the can_be_granted() above set the grmode
1969 if (is_demoted(lkb)) 2023 to NL, and left us on the granted queue. This auto-demotion
2024 (due to CONVDEADLK) might mean other locks, and/or this lock, are
2025 now grantable. We have to try to grant other converting locks
2026 before we try again to grant this one. */
2027
2028 if (is_demoted(lkb)) {
2029 grant_pending_convert(r, DLM_LOCK_IV);
2030 if (_can_be_granted(r, lkb, 1)) {
2031 grant_lock(r, lkb);
2032 queue_cast(r, lkb, 0);
1970 grant_pending_locks(r); 2033 grant_pending_locks(r);
2034 goto out;
2035 }
2036 /* else fall through and move to convert queue */
2037 }
2038
2039 if (can_be_queued(lkb)) {
1971 error = -EINPROGRESS; 2040 error = -EINPROGRESS;
1972 del_lkb(r, lkb); 2041 del_lkb(r, lkb);
1973 add_lkb(r, lkb, DLM_LKSTS_CONVERT); 2042 add_lkb(r, lkb, DLM_LKSTS_CONVERT);
@@ -2908,6 +2977,8 @@ static void receive_grant(struct dlm_ls *ls, struct dlm_message *ms)
2908 lock_rsb(r); 2977 lock_rsb(r);
2909 2978
2910 receive_flags_reply(lkb, ms); 2979 receive_flags_reply(lkb, ms);
2980 if (is_altmode(lkb))
2981 munge_altmode(lkb, ms);
2911 grant_lock_pc(r, lkb, ms); 2982 grant_lock_pc(r, lkb, ms);
2912 queue_cast(r, lkb, 0); 2983 queue_cast(r, lkb, 0);
2913 2984
@@ -3038,6 +3109,8 @@ static void receive_request_reply(struct dlm_ls *ls, struct dlm_message *ms)
3038 /* request was queued or granted on remote master */ 3109 /* request was queued or granted on remote master */
3039 receive_flags_reply(lkb, ms); 3110 receive_flags_reply(lkb, ms);
3040 lkb->lkb_remid = ms->m_lkid; 3111 lkb->lkb_remid = ms->m_lkid;
3112 if (is_altmode(lkb))
3113 munge_altmode(lkb, ms);
3041 if (result) 3114 if (result)
3042 add_lkb(r, lkb, DLM_LKSTS_WAITING); 3115 add_lkb(r, lkb, DLM_LKSTS_WAITING);
3043 else { 3116 else {
@@ -3101,6 +3174,9 @@ static void __receive_convert_reply(struct dlm_rsb *r, struct dlm_lkb *lkb,
3101 3174
3102 case -EINPROGRESS: 3175 case -EINPROGRESS:
3103 /* convert was queued on remote master */ 3176 /* convert was queued on remote master */
3177 receive_flags_reply(lkb, ms);
3178 if (is_demoted(lkb))
3179 munge_demoted(lkb, ms);
3104 del_lkb(r, lkb); 3180 del_lkb(r, lkb);
3105 add_lkb(r, lkb, DLM_LKSTS_CONVERT); 3181 add_lkb(r, lkb, DLM_LKSTS_CONVERT);
3106 break; 3182 break;
@@ -3108,6 +3184,8 @@ static void __receive_convert_reply(struct dlm_rsb *r, struct dlm_lkb *lkb,
3108 case 0: 3184 case 0:
3109 /* convert was granted on remote master */ 3185 /* convert was granted on remote master */
3110 receive_flags_reply(lkb, ms); 3186 receive_flags_reply(lkb, ms);
3187 if (is_demoted(lkb))
3188 munge_demoted(lkb, ms);
3111 grant_lock_pc(r, lkb, ms); 3189 grant_lock_pc(r, lkb, ms);
3112 queue_cast(r, lkb, 0); 3190 queue_cast(r, lkb, 0);
3113 break; 3191 break;