6.10-stable review patch. If anyone has any objections, please let me know.
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From: Heming Zhao heming.zhao@suse.com
[ Upstream commit fff42f213824fa434a4b6cf906b4331fe6e9302b ]
The commit 1bbe254e4336 ("md-cluster: check for timeout while a new disk adding") is correct in terms of code syntax but not suite real clustered code logic.
When a timeout occurs while adding a new disk, if recv_daemon() bypasses the unlock for ack_lockres:CR, another node will be waiting to grab EX lock. This will cause the cluster to hang indefinitely.
How to fix:
1. In dlm_lock_sync(), change the wait behaviour from forever to a timeout, This could avoid the hanging issue when another node fails to handle cluster msg. Another result of this change is that if another node receives an unknown msg (e.g. a new msg_type), the old code will hang, whereas the new code will timeout and fail. This could help cluster_md handle new msg_type from different nodes with different kernel/module versions (e.g. The user only updates one leg's kernel and monitors the stability of the new kernel). 2. The old code for __sendmsg() always returns 0 (success) under the design (must successfully unlock ->message_lockres). This commit makes this function return an error number when an error occurs.
Fixes: 1bbe254e4336 ("md-cluster: check for timeout while a new disk adding") Signed-off-by: Heming Zhao heming.zhao@suse.com Reviewed-by: Su Yue glass.su@suse.com Acked-by: Yu Kuai yukuai3@huawei.com Signed-off-by: Song Liu song@kernel.org Link: https://lore.kernel.org/r/20240709104120.22243-1-heming.zhao@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/md/md-cluster.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-)
diff --git a/drivers/md/md-cluster.c b/drivers/md/md-cluster.c index 8e36a0feec098..b5a802ae17bb2 100644 --- a/drivers/md/md-cluster.c +++ b/drivers/md/md-cluster.c @@ -15,6 +15,7 @@
#define LVB_SIZE 64 #define NEW_DEV_TIMEOUT 5000 +#define WAIT_DLM_LOCK_TIMEOUT (30 * HZ)
struct dlm_lock_resource { dlm_lockspace_t *ls; @@ -130,8 +131,13 @@ static int dlm_lock_sync(struct dlm_lock_resource *res, int mode) 0, sync_ast, res, res->bast); if (ret) return ret; - wait_event(res->sync_locking, res->sync_locking_done); + ret = wait_event_timeout(res->sync_locking, res->sync_locking_done, + WAIT_DLM_LOCK_TIMEOUT); res->sync_locking_done = false; + if (!ret) { + pr_err("locking DLM '%s' timeout!\n", res->name); + return -EBUSY; + } if (res->lksb.sb_status == 0) res->mode = mode; return res->lksb.sb_status; @@ -743,7 +749,7 @@ static void unlock_comm(struct md_cluster_info *cinfo) */ static int __sendmsg(struct md_cluster_info *cinfo, struct cluster_msg *cmsg) { - int error; + int error, unlock_error; int slot = cinfo->slot_number - 1;
cmsg->slot = cpu_to_le32(slot); @@ -751,7 +757,7 @@ static int __sendmsg(struct md_cluster_info *cinfo, struct cluster_msg *cmsg) error = dlm_lock_sync(cinfo->message_lockres, DLM_LOCK_EX); if (error) { pr_err("md-cluster: failed to get EX on MESSAGE (%d)\n", error); - goto failed_message; + return error; }
memcpy(cinfo->message_lockres->lksb.sb_lvbptr, (void *)cmsg, @@ -781,14 +787,10 @@ static int __sendmsg(struct md_cluster_info *cinfo, struct cluster_msg *cmsg) }
failed_ack: - error = dlm_unlock_sync(cinfo->message_lockres); - if (unlikely(error != 0)) { + while ((unlock_error = dlm_unlock_sync(cinfo->message_lockres))) pr_err("md-cluster: failed convert to NL on MESSAGE(%d)\n", - error); - /* in case the message can't be released due to some reason */ - goto failed_ack; - } -failed_message: + unlock_error); + return error; }