summaryrefslogtreecommitdiff
path: root/fs/locks.c
diff options
context:
space:
mode:
authorAlexander Aring <aahringo@redhat.com>2023-09-12 17:53:21 -0400
committerChuck Lever <chuck.lever@oracle.com>2023-10-16 12:44:02 -0400
commite70da17633ee9457cae39e4f5f2fc5efafb7a99b (patch)
tree748e120c718db677350781a17df296300cdd4455 /fs/locks.c
parentafb13302aa664170684c76b0c12ece37b4e91d12 (diff)
lockd: add doc to enable EXPORT_OP_ASYNC_LOCK
This patch adds a note to enable EXPORT_OP_ASYNC_LOCK for asynchronous lock request handling. Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to 'fs/locks.c')
-rw-r--r--fs/locks.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/fs/locks.c b/fs/locks.c
index 76ad05f8070a..d4e49a990a8d 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2264,11 +2264,13 @@ out:
* To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
* locks, the ->lock() interface may return asynchronously, before the lock has
* been granted or denied by the underlying filesystem, if (and only if)
- * lm_grant is set. Callers expecting ->lock() to return asynchronously
- * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
- * the request is for a blocking lock. When ->lock() does return asynchronously,
- * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock
- * request completes.
+ * lm_grant is set. Additionally EXPORT_OP_ASYNC_LOCK in export_operations
+ * flags need to be set.
+ *
+ * Callers expecting ->lock() to return asynchronously will only use F_SETLK,
+ * not F_SETLKW; they will set FL_SLEEP if (and only if) the request is for a
+ * blocking lock. When ->lock() does return asynchronously, it must return
+ * FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock request completes.
* If the request is for non-blocking lock the file system should return
* FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
* with the result. If the request timed out the callback routine will return a