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LU-5319 mdc: manage number of modify RPCs in flight
[fs/lustre-release.git] / lustre / include / lustre_mdc.h
index f095a71..f09f327 100644 (file)
@@ -1,6 +1,4 @@
-/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
- * vim:expandtab:shiftwidth=8:tabstop=8:
- *
+/*
  * GPL HEADER START
  *
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
@@ -30,6 +28,9 @@
  * Use is subject to license terms.
  */
 /*
+ * Copyright (c) 2011, 2014, Intel Corporation.
+ */
+/*
  * This file is part of Lustre, http://www.lustre.org/
  * Lustre is a trademark of Sun Microsystems, Inc.
  *
  * @{
  */
 
-#ifdef __KERNEL__
-# include <linux/fs.h>
-# include <linux/dcache.h>
-# ifdef CONFIG_FS_POSIX_ACL
-#  ifdef HAVE_XATTR_ACL
-#   include <linux/xattr_acl.h>
-#  endif /*HAVE_XATTR_ACL */
-#  ifdef HAVE_LINUX_POSIX_ACL_XATTR_H
-#   include <linux/posix_acl_xattr.h>
-#  endif /* HAVE_LINUX_POSIX_ACL_XATTR_H */
-# endif /* CONFIG_FS_POSIX_ACL */
-# ifndef HAVE_VFS_INTENT_PATCHES
-# include <linux/lustre_intent.h>
-# endif /* HAVE_VFS_INTENT_PATCHES */
-#endif /* __KERNEL__ */
+#include <linux/fs.h>
+#include <linux/dcache.h>
+#ifdef CONFIG_FS_POSIX_ACL
+# include <linux/posix_acl_xattr.h>
+#endif /* CONFIG_FS_POSIX_ACL */
 #include <lustre_handles.h>
+#include <lustre_intent.h>
 #include <libcfs/libcfs.h>
+#include <obd_class.h>
 #include <lustre/lustre_idl.h>
 #include <lustre_lib.h>
 #include <lustre_dlm.h>
-#include <lustre_log.h>
 #include <lustre_export.h>
 
 struct ptlrpc_client;
@@ -75,68 +67,176 @@ struct obd_export;
 struct ptlrpc_request;
 struct obd_device;
 
+/**
+ * Serializes in-flight MDT-modifying RPC requests to preserve idempotency.
+ *
+ * This mutex is used to implement execute-once semantics on the MDT.
+ * The MDT stores the last transaction ID and result for every client in
+ * its last_rcvd file. If the client doesn't get a reply, it can safely
+ * resend the request and the MDT will reconstruct the reply being aware
+ * that the request has already been executed. Without this lock,
+ * execution status of concurrent in-flight requests would be
+ * overwritten.
+ *
+ * This design limits the extent to which we can keep a full pipeline of
+ * in-flight requests from a single client.  This limitation could be
+ * overcome by allowing multiple slots per client in the last_rcvd file.
+ */
 struct mdc_rpc_lock {
-        cfs_semaphore_t  rpcl_sem;
-        struct lookup_intent *rpcl_it;
+       /** Lock protecting in-flight RPC concurrency. */
+       struct mutex            rpcl_mutex;
+       /** Intent associated with currently executing request. */
+       struct lookup_intent    *rpcl_it;
+       /** Used for MDS/RPC load testing purposes. */
+       int                     rpcl_fakes;
 };
 
+#define MDC_FAKE_RPCL_IT ((void *)0x2c0012bfUL)
+
 static inline void mdc_init_rpc_lock(struct mdc_rpc_lock *lck)
 {
-        cfs_sema_init(&lck->rpcl_sem, 1);
+       mutex_init(&lck->rpcl_mutex);
         lck->rpcl_it = NULL;
 }
 
 static inline void mdc_get_rpc_lock(struct mdc_rpc_lock *lck,
-                                    struct lookup_intent *it)
+                                   struct lookup_intent *it)
 {
-        ENTRY;
-        if (!it || (it->it_op != IT_GETATTR && it->it_op != IT_LOOKUP)) {
-                cfs_down(&lck->rpcl_sem);
-                LASSERT(lck->rpcl_it == NULL);
-                lck->rpcl_it = it;
-        }
+       ENTRY;
+
+       if (it != NULL && (it->it_op == IT_GETATTR || it->it_op == IT_LOOKUP ||
+                          it->it_op == IT_LAYOUT || it->it_op == IT_READDIR))
+               return;
+
+       /* This would normally block until the existing request finishes.
+        * If fail_loc is set it will block until the regular request is
+        * done, then set rpcl_it to MDC_FAKE_RPCL_IT.  Once that is set
+        * it will only be cleared when all fake requests are finished.
+        * Only when all fake requests are finished can normal requests
+        * be sent, to ensure they are recoverable again. */
+ again:
+       mutex_lock(&lck->rpcl_mutex);
+
+       if (CFS_FAIL_CHECK_QUIET(OBD_FAIL_MDC_RPCS_SEM)) {
+               lck->rpcl_it = MDC_FAKE_RPCL_IT;
+               lck->rpcl_fakes++;
+               mutex_unlock(&lck->rpcl_mutex);
+               return;
+       }
+
+       /* This will only happen when the CFS_FAIL_CHECK() was
+        * just turned off but there are still requests in progress.
+        * Wait until they finish.  It doesn't need to be efficient
+        * in this extremely rare case, just have low overhead in
+        * the common case when it isn't true. */
+       while (unlikely(lck->rpcl_it == MDC_FAKE_RPCL_IT)) {
+               mutex_unlock(&lck->rpcl_mutex);
+               schedule_timeout(cfs_time_seconds(1) / 4);
+               goto again;
+       }
+
+       LASSERT(lck->rpcl_it == NULL);
+       lck->rpcl_it = it;
 }
 
 static inline void mdc_put_rpc_lock(struct mdc_rpc_lock *lck,
-                                    struct lookup_intent *it)
+                                   struct lookup_intent *it)
 {
-        if (!it || (it->it_op != IT_GETATTR && it->it_op != IT_LOOKUP)) {
-                LASSERT(it == lck->rpcl_it);
-                lck->rpcl_it = NULL;
-                cfs_up(&lck->rpcl_sem);
-        }
-        EXIT;
+       if (it != NULL && (it->it_op == IT_GETATTR || it->it_op == IT_LOOKUP ||
+                          it->it_op == IT_LAYOUT || it->it_op == IT_READDIR))
+               goto out;
+
+       if (lck->rpcl_it == MDC_FAKE_RPCL_IT) { /* OBD_FAIL_MDC_RPCS_SEM */
+               mutex_lock(&lck->rpcl_mutex);
+
+               LASSERTF(lck->rpcl_fakes > 0, "%d\n", lck->rpcl_fakes);
+               lck->rpcl_fakes--;
+
+               if (lck->rpcl_fakes == 0)
+                       lck->rpcl_it = NULL;
+
+       } else {
+               LASSERTF(it == lck->rpcl_it, "%p != %p\n", it, lck->rpcl_it);
+               lck->rpcl_it = NULL;
+       }
+
+       mutex_unlock(&lck->rpcl_mutex);
+ out:
+       EXIT;
 }
 
-static inline void mdc_update_max_ea_from_body(struct obd_export *exp,
-                                               struct mdt_body *body)
+static inline void mdc_get_mod_rpc_slot(struct ptlrpc_request *req,
+                                       struct lookup_intent *it)
 {
-        if (body->valid & OBD_MD_FLMODEASIZE) {
-                if (exp->exp_obd->u.cli.cl_max_mds_easize < body->max_mdsize)
-                        exp->exp_obd->u.cli.cl_max_mds_easize =
-                                                body->max_mdsize;
-                if (exp->exp_obd->u.cli.cl_max_mds_cookiesize <
-                                                body->max_cookiesize)
-                        exp->exp_obd->u.cli.cl_max_mds_cookiesize =
-                                                body->max_cookiesize;
-        }
+       struct client_obd *cli = &req->rq_import->imp_obd->u.cli;
+       __u32 opc;
+       __u16 tag;
+
+       opc = lustre_msg_get_opc(req->rq_reqmsg);
+       tag = obd_get_mod_rpc_slot(cli, opc, it);
+       lustre_msg_set_tag(req->rq_reqmsg, tag);
 }
 
+static inline void mdc_put_mod_rpc_slot(struct ptlrpc_request *req,
+                                       struct lookup_intent *it)
+{
+       struct client_obd *cli = &req->rq_import->imp_obd->u.cli;
+       __u32 opc;
+       __u16 tag;
+
+       opc = lustre_msg_get_opc(req->rq_reqmsg);
+       tag = lustre_msg_get_tag(req->rq_reqmsg);
+       obd_put_mod_rpc_slot(cli, opc, it, tag);
+}
+
+
+/**
+ * Update the maximum possible easize.
+ *
+ * This value is learned from ptlrpc replies sent by the MDT.  The
+ * default easize is initialized to the minimum value but allowed to
+ * grow up to a single page in size if required to handle the common
+ * case.
+ *
+ * \see client_obd::cl_default_mds_easize
+ *
+ * \param[in] exp      export for MDC device
+ * \param[in] body     body of ptlrpc reply from MDT
+ *
+ */
+static inline void mdc_update_max_ea_from_body(struct obd_export *exp,
+                                              struct mdt_body *body)
+{
+       if (body->mbo_valid & OBD_MD_FLMODEASIZE) {
+               struct client_obd *cli = &exp->exp_obd->u.cli;
+               __u32 def_easize;
+
+               if (cli->cl_max_mds_easize < body->mbo_max_mdsize)
+                       cli->cl_max_mds_easize = body->mbo_max_mdsize;
+
+               def_easize = min_t(__u32, body->mbo_max_mdsize,
+                                  OBD_MAX_DEFAULT_EA_SIZE);
+               cli->cl_default_mds_easize = def_easize;
+       }
+}
 
-struct mdc_cache_waiter {
-        cfs_list_t              mcw_entry;
-        cfs_waitq_t             mcw_waitq;
-};
 
 /* mdc/mdc_locks.c */
-int it_disposition(struct lookup_intent *it, int flag);
-void it_clear_disposition(struct lookup_intent *it, int flag);
-void it_set_disposition(struct lookup_intent *it, int flag);
 int it_open_error(int phase, struct lookup_intent *it);
-#ifdef HAVE_SPLIT_SUPPORT
-int mdc_sendpage(struct obd_export *exp, const struct lu_fid *fid,
-                 const struct page *page, int offset);
-#endif
+
+static inline bool cl_is_lov_delay_create(unsigned int flags)
+{
+       return  (flags & O_LOV_DELAY_CREATE_1_8) != 0 ||
+               (flags & O_LOV_DELAY_CREATE_MASK) == O_LOV_DELAY_CREATE_MASK;
+}
+
+static inline void cl_lov_delay_create_clear(unsigned int *flags)
+{
+       if ((*flags & O_LOV_DELAY_CREATE_1_8) != 0)
+               *flags &= ~O_LOV_DELAY_CREATE_1_8;
+       if ((*flags & O_LOV_DELAY_CREATE_MASK) == O_LOV_DELAY_CREATE_MASK)
+               *flags &= ~O_LOV_DELAY_CREATE_MASK;
+}
 
 /** @} mdc */