LU-9771 clio: introduce CIT_GLIMPSE for glimpse

[fs/lustre-release.git] / lustre / llite / glimpse.c

diff --git a/lustre/llite/glimpse.c b/lustre/llite/glimpse.c
index f0751e7..7c9ec0d 100644 (file)
--- a/lustre/llite/glimpse.c
+++ b/lustre/llite/glimpse.c
@@ -15,11 +15,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * version 2 along with this program; If not, see
- * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
- *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
+ * http://www.gnu.org/licenses/gpl-2.0.html
  *
  * GPL HEADER END
  */
@@ -27,14 +23,13 @@
  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
  *
- * Copyright (c) 2011, 2014, Intel Corporation.
+ * Copyright (c) 2011, 2016, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
  * Lustre is a trademark of Sun Microsystems, Inc.
  *
- * glimpse code shared between vvp and liblustre (and other Lustre clients in
- * the future).
+ * glimpse code used by vvp (and other Lustre clients in the future).
  *
  *   Author: Nikita Danilov <nikita.danilov@sun.com>
  *   Author: Oleg Drokin <oleg.drokin@sun.com>
@@ -96,7 +91,7 @@ int cl_glimpse_lock(const struct lu_env *env, struct cl_io *io,
        CDEBUG(D_DLMTRACE, "Glimpsing inode "DFID"\n", PFID(fid));
 
        /* NOTE: this looks like DLM lock request, but it may
-        *       not be one. Due to CEF_ASYNC flag (translated
+        *       not be one. Due to CEF_GLIMPSE flag (translated
         *       to LDLM_FL_HAS_INTENT by osc), this is
         *       glimpse request, that won't revoke any
         *       conflicting DLM locks held. Instead,
@@ -111,14 +106,10 @@ int cl_glimpse_lock(const struct lu_env *env, struct cl_io *io,
        *descr = whole_file;
        descr->cld_obj = clob;
        descr->cld_mode = CLM_READ;
-       descr->cld_enq_flags = CEF_ASYNC | CEF_MUST;
+       descr->cld_enq_flags = CEF_GLIMPSE | CEF_MUST;
        if (agl)
-               descr->cld_enq_flags |= CEF_AGL;
+               descr->cld_enq_flags |= CEF_SPECULATIVE | CEF_NONBLOCK;
        /*
-        * CEF_ASYNC is used because glimpse sub-locks cannot
-        * deadlock (because they never conflict with other
-        * locks) and, hence, can be enqueued out-of-order.
-        *
         * CEF_MUST protects glimpse lock from conversion into
         * a lockless mode.
         */
@@ -144,7 +135,20 @@ int cl_glimpse_lock(const struct lu_env *env, struct cl_io *io,
        RETURN(result);
 }
 
-static int cl_io_get(struct inode *inode, struct lu_env **envout,
+/**
+ * Get an IO environment for special operations such as glimpse locks and
+ * manually requested locks (ladvise lockahead)
+ *
+ * \param[in]  inode   inode the operation is being performed on
+ * \param[out] envout  thread specific execution environment
+ * \param[out] ioout   client io description
+ * \param[out] refcheck        reference check
+ *
+ * \retval 1           on success
+ * \retval 0           not a regular file, cannot get environment
+ * \retval negative    negative errno on error
+ */
+int cl_io_get(struct inode *inode, struct lu_env **envout,
                     struct cl_io **ioout, __u16 *refcheck)
 {
        struct lu_env           *env;
@@ -182,16 +186,19 @@ int cl_glimpse_size0(struct inode *inode, int agl)
          */
         struct lu_env          *env = NULL;
         struct cl_io           *io  = NULL;
-       __u16                   refcheck;
+       __u16                   refcheck;
         int                     result;
 
         ENTRY;
 
-        result = cl_io_get(inode, &env, &io, &refcheck);
-        if (result > 0) {
-       again:
+       result = cl_io_get(inode, &env, &io, &refcheck);
+       if (result <= 0)
+               RETURN(result);
+
+       do {
+               io->ci_need_restart = 0;
                io->ci_verify_layout = 1;
-                result = cl_io_init(env, io, CIT_MISC, io->ci_obj);
+               result = cl_io_init(env, io, CIT_GLIMPSE, io->ci_obj);
                 if (result > 0)
                         /*
                          * nothing to do for this io. This currently happens
@@ -200,13 +207,12 @@ int cl_glimpse_size0(struct inode *inode, int agl)
                         result = io->ci_result;
                 else if (result == 0)
                         result = cl_glimpse_lock(env, io, inode, io->ci_obj,
-                                                 agl);
+                                                agl);
 
                OBD_FAIL_TIMEOUT(OBD_FAIL_GLIMPSE_DELAY, 2);
-                cl_io_fini(env, io);
-               if (unlikely(io->ci_need_restart))
-                       goto again;
-               cl_env_put(env, &refcheck);
-       }
+               cl_io_fini(env, io);
+       } while (unlikely(io->ci_need_restart));
+
+       cl_env_put(env, &refcheck);
        RETURN(result);
 }