Whamcloud - gitweb
LU-11943 llog: Reset current log on ENOSPC
[fs/lustre-release.git] / lustre / obdclass / llog_cat.c
index 0d57ce3..c5b15f1 100644 (file)
@@ -23,7 +23,7 @@
  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
  *
- * Copyright (c) 2012, 2016, Intel Corporation.
+ * Copyright (c) 2012, 2017, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
 
 #include "llog_internal.h"
 
+
+/**
+ * lockdep markers for nested struct llog_handle::lgh_lock locking.
+ */
+enum {
+       LLOGH_CAT,
+       LLOGH_LOG,
+};
+
 /* Create a new log handle and add it to the open list.
  * This log handle will be closed when all of the records in it are removed.
  *
@@ -213,11 +222,137 @@ out_destroy:
        loghandle->lgh_hdr->llh_flags &= ~LLOG_F_ZAP_WHEN_EMPTY;
        /* this is to mimic full log, so another llog_cat_current_log()
         * can skip it and ask for another onet */
-       loghandle->lgh_last_idx = LLOG_HDR_BITMAP_SIZE(llh) + 1;
+       loghandle->lgh_last_idx = LLOG_HDR_BITMAP_SIZE(loghandle->lgh_hdr) + 1;
        llog_trans_destroy(env, loghandle, th);
+       if (handle != NULL)
+               dt_trans_stop(env, dt, handle);
        RETURN(rc);
 }
 
+static int llog_cat_refresh(const struct lu_env *env,
+                           struct llog_handle *cathandle)
+{
+       struct llog_handle *loghandle;
+       int rc;
+
+       down_write(&cathandle->lgh_lock);
+       list_for_each_entry(loghandle, &cathandle->u.chd.chd_head,
+                           u.phd.phd_entry) {
+               if (!llog_exist(loghandle))
+                       continue;
+
+               rc = llog_read_header(env, loghandle, NULL);
+               if (rc)
+                       goto unlock;
+       }
+
+       rc = llog_read_header(env, cathandle, NULL);
+unlock:
+       up_write(&loghandle->lgh_lock);
+
+       return rc;
+}
+
+/*
+ * prepare current/next log for catalog.
+ *
+ * if \a *ploghandle is NULL, open it, and declare create, NB, if \a
+ * *ploghandle is remote, create it synchronously here, see comments
+ * below.
+ *
+ * \a cathandle->lgh_lock is down_read-ed, it gets down_write-ed if \a
+ * *ploghandle has to be opened.
+ */
+static int llog_cat_prep_log(const struct lu_env *env,
+                            struct llog_handle *cathandle,
+                            struct llog_handle **ploghandle,
+                            struct thandle *th)
+{
+       int rc;
+       int sem_upgraded;
+
+start:
+       rc = 0;
+       sem_upgraded = 0;
+       if (IS_ERR_OR_NULL(*ploghandle)) {
+               up_read(&cathandle->lgh_lock);
+               down_write(&cathandle->lgh_lock);
+               sem_upgraded = 1;
+               if (IS_ERR_OR_NULL(*ploghandle)) {
+                       struct llog_handle *loghandle;
+
+                       rc = llog_open(env, cathandle->lgh_ctxt, &loghandle,
+                                      NULL, NULL, LLOG_OPEN_NEW);
+                       if (!rc) {
+                               *ploghandle = loghandle;
+                               list_add_tail(&loghandle->u.phd.phd_entry,
+                                             &cathandle->u.chd.chd_head);
+                       }
+               }
+               if (rc)
+                       GOTO(out, rc);
+       }
+
+       rc = llog_exist(*ploghandle);
+       if (rc < 0)
+               GOTO(out, rc);
+       if (rc)
+               GOTO(out, rc = 0);
+
+       if (dt_object_remote(cathandle->lgh_obj)) {
+               down_write_nested(&(*ploghandle)->lgh_lock, LLOGH_LOG);
+               if (!llog_exist(*ploghandle)) {
+                       /* For remote operation, if we put the llog object
+                        * creation in the current transaction, then the
+                        * llog object will not be created on the remote
+                        * target until the transaction stop, if other
+                        * operations start before the transaction stop,
+                        * and use the same llog object, will be dependent
+                        * on the success of this transaction. So let's
+                        * create the llog object synchronously here to
+                        * remove the dependency. */
+                       rc = llog_cat_new_log(env, cathandle, *ploghandle,
+                                             NULL);
+                       if (rc == -ESTALE) {
+                               up_write(&(*ploghandle)->lgh_lock);
+                               if (sem_upgraded)
+                                       up_write(&cathandle->lgh_lock);
+                               else
+                                       up_read(&cathandle->lgh_lock);
+
+                               rc = llog_cat_refresh(env, cathandle);
+                               down_read_nested(&cathandle->lgh_lock,
+                                                LLOGH_CAT);
+                               if (rc)
+                                       return rc;
+                               /* *ploghandle might become NULL, restart */
+                               goto start;
+                       }
+               }
+               up_write(&(*ploghandle)->lgh_lock);
+       } else {
+               struct llog_thread_info *lgi = llog_info(env);
+               struct llog_logid_rec *lirec = &lgi->lgi_logid;
+
+               rc = llog_declare_create(env, *ploghandle, th);
+               if (rc)
+                       GOTO(out, rc);
+
+               lirec->lid_hdr.lrh_len = sizeof(*lirec);
+               rc = llog_declare_write_rec(env, cathandle, &lirec->lid_hdr, -1,
+                                           th);
+       }
+
+out:
+       if (sem_upgraded) {
+               up_write(&cathandle->lgh_lock);
+               down_read_nested(&cathandle->lgh_lock, LLOGH_CAT);
+               if (rc == 0)
+                       goto start;
+       }
+       return rc;
+}
+
 /* Open an existent log handle and add it to the open list.
  * This log handle will be closed when all of the records in it are removed.
  *
@@ -330,14 +465,6 @@ int llog_cat_close(const struct lu_env *env, struct llog_handle *cathandle)
 }
 EXPORT_SYMBOL(llog_cat_close);
 
-/**
- * lockdep markers for nested struct llog_handle::lgh_lock locking.
- */
-enum {
-        LLOGH_CAT,
-        LLOGH_LOG
-};
-
 /** Return the currently active log handle.  If the current log handle doesn't
  * have enough space left for the current record, start a new one.
  *
@@ -386,8 +513,7 @@ static struct llog_handle *llog_cat_current_log(struct llog_handle *cathandle,
 
                down_write_nested(&loghandle->lgh_lock, LLOGH_LOG);
                llh = loghandle->lgh_hdr;
-               LASSERT(llh);
-               if (!llog_is_full(loghandle))
+               if (llh == NULL || !llog_is_full(loghandle))
                        GOTO(out_unlock, loghandle);
                else
                        up_write(&loghandle->lgh_lock);
@@ -426,40 +552,6 @@ out_unlock:
        RETURN(loghandle);
 }
 
-static int llog_cat_update_header(const struct lu_env *env,
-                          struct llog_handle *cathandle)
-{
-       struct llog_handle *loghandle;
-       int rc;
-       ENTRY;
-
-       /* refresh llog */
-       down_write(&cathandle->lgh_lock);
-       if (!cathandle->lgh_stale) {
-               up_write(&cathandle->lgh_lock);
-               RETURN(0);
-       }
-       list_for_each_entry(loghandle, &cathandle->u.chd.chd_head,
-                           u.phd.phd_entry) {
-               if (!llog_exist(loghandle))
-                       continue;
-
-               rc = llog_read_header(env, loghandle, NULL);
-               if (rc != 0) {
-                       up_write(&cathandle->lgh_lock);
-                       GOTO(out, rc);
-               }
-       }
-       rc = llog_read_header(env, cathandle, NULL);
-       if (rc == 0)
-               cathandle->lgh_stale = 0;
-       up_write(&cathandle->lgh_lock);
-       if (rc != 0)
-               GOTO(out, rc);
-out:
-       RETURN(rc);
-}
-
 /* Add a single record to the recovery log(s) using a catalog
  * Returns as llog_write_record
  *
@@ -524,167 +616,43 @@ int llog_cat_declare_add_rec(const struct lu_env *env,
                             struct llog_handle *cathandle,
                             struct llog_rec_hdr *rec, struct thandle *th)
 {
-       struct llog_thread_info *lgi = llog_info(env);
-       struct llog_logid_rec   *lirec = &lgi->lgi_logid;
-       struct llog_handle      *loghandle, *next;
-       int                      rc = 0;
+       int rc;
 
        ENTRY;
 
-       if (cathandle->u.chd.chd_current_log == NULL) {
-               /* declare new plain llog */
-               down_write(&cathandle->lgh_lock);
-               if (cathandle->u.chd.chd_current_log == NULL) {
-                       rc = llog_open(env, cathandle->lgh_ctxt, &loghandle,
-                                      NULL, NULL, LLOG_OPEN_NEW);
-                       if (rc == 0) {
-                               cathandle->u.chd.chd_current_log = loghandle;
-                               list_add_tail(&loghandle->u.phd.phd_entry,
-                                             &cathandle->u.chd.chd_head);
-                       }
-               }
-               up_write(&cathandle->lgh_lock);
-       } else if (cathandle->u.chd.chd_next_log == NULL ||
-                  IS_ERR(cathandle->u.chd.chd_next_log)) {
-               /* declare next plain llog */
-               down_write(&cathandle->lgh_lock);
-               if (cathandle->u.chd.chd_next_log == NULL ||
-                   IS_ERR(cathandle->u.chd.chd_next_log)) {
-                       rc = llog_open(env, cathandle->lgh_ctxt, &loghandle,
-                                      NULL, NULL, LLOG_OPEN_NEW);
-                       if (rc == 0) {
-                               cathandle->u.chd.chd_next_log = loghandle;
-                               list_add_tail(&loghandle->u.phd.phd_entry,
-                                             &cathandle->u.chd.chd_head);
-                       }
-               }
-               up_write(&cathandle->lgh_lock);
-       }
+start:
+       down_read_nested(&cathandle->lgh_lock, LLOGH_CAT);
+       rc = llog_cat_prep_log(env, cathandle,
+                              &cathandle->u.chd.chd_current_log, th);
        if (rc)
-               GOTO(out, rc);
-
-       lirec->lid_hdr.lrh_len = sizeof(*lirec);
+               GOTO(unlock, rc);
 
-       if (!llog_exist(cathandle->u.chd.chd_current_log)) {
-               if (dt_object_remote(cathandle->lgh_obj)) {
-                       /* For remote operation, if we put the llog object
-                        * creation in the current transaction, then the
-                        * llog object will not be created on the remote
-                        * target until the transaction stop, if other
-                        * operations start before the transaction stop,
-                        * and use the same llog object, will be dependent
-                        * on the success of this transaction. So let's
-                        * create the llog object synchronously here to
-                        * remove the dependency. */
-create_again:
-                       down_read_nested(&cathandle->lgh_lock, LLOGH_CAT);
-                       loghandle = cathandle->u.chd.chd_current_log;
-                       down_write_nested(&loghandle->lgh_lock, LLOGH_LOG);
-                       if (cathandle->lgh_stale) {
-                               up_write(&loghandle->lgh_lock);
-                               up_read(&cathandle->lgh_lock);
-                               GOTO(out, rc = -EIO);
-                       }
-                       if (!llog_exist(loghandle)) {
-                               rc = llog_cat_new_log(env, cathandle, loghandle,
-                                                     NULL);
-                               if (rc == -ESTALE)
-                                       cathandle->lgh_stale = 1;
-                       }
-                       up_write(&loghandle->lgh_lock);
-                       up_read(&cathandle->lgh_lock);
-                       if (rc == -ESTALE) {
-                               rc = llog_cat_update_header(env, cathandle);
-                               if (rc != 0)
-                                       GOTO(out, rc);
-                               goto create_again;
-                       } else if (rc < 0) {
-                               GOTO(out, rc);
-                       }
-               } else {
-                       rc = llog_declare_create(env,
-                                       cathandle->u.chd.chd_current_log, th);
-                       if (rc)
-                               GOTO(out, rc);
-                       llog_declare_write_rec(env, cathandle,
-                                              &lirec->lid_hdr, -1, th);
-               }
-       }
+       rc = llog_cat_prep_log(env, cathandle, &cathandle->u.chd.chd_next_log,
+                              th);
+       if (rc)
+               GOTO(unlock, rc);
 
-write_again:
-       /* declare records in the llogs */
        rc = llog_declare_write_rec(env, cathandle->u.chd.chd_current_log,
                                    rec, -1, th);
-       if (rc == -ESTALE) {
-               down_write(&cathandle->lgh_lock);
-               if (cathandle->lgh_stale) {
-                       up_write(&cathandle->lgh_lock);
-                       GOTO(out, rc = -EIO);
-               }
-
-               cathandle->lgh_stale = 1;
-               up_write(&cathandle->lgh_lock);
-               rc = llog_cat_update_header(env, cathandle);
-               if (rc != 0)
-                       GOTO(out, rc);
-               goto write_again;
-       } else if (rc < 0) {
-               GOTO(out, rc);
+       if (rc == -ESTALE && dt_object_remote(cathandle->lgh_obj)) {
+               up_read(&cathandle->lgh_lock);
+               rc = llog_cat_refresh(env, cathandle);
+               if (rc)
+                       RETURN(rc);
+               goto start;
        }
 
-       next = cathandle->u.chd.chd_next_log;
-       if (!IS_ERR_OR_NULL(next)) {
-               if (!llog_exist(next)) {
-                       if (dt_object_remote(cathandle->lgh_obj)) {
-                               /* For remote operation, if we put the llog
-                                * object creation in the current transaction,
-                                * then the llog object will not be created on
-                                * the remote target until the transaction stop,
-                                * if other operations start before the
-                                * transaction stop, and use the same llog
-                                * object, will be dependent on the success of
-                                * this transaction. So let's create the llog
-                                * object synchronously here to remove the
-                                * dependency. */
-                               down_write_nested(&cathandle->lgh_lock,
-                                                LLOGH_CAT);
-                               next = cathandle->u.chd.chd_next_log;
-                               if (IS_ERR_OR_NULL(next)) {
-                                       /* Sigh, another thread just tried,
-                                        * let's fail as well */
-                                       up_write(&cathandle->lgh_lock);
-                                       if (next == NULL)
-                                               rc = -EIO;
-                                       else
-                                               rc = PTR_ERR(next);
-                                       GOTO(out, rc);
-                               }
-
-                               down_write_nested(&next->lgh_lock, LLOGH_LOG);
-                               if (!llog_exist(next)) {
-                                       rc = llog_cat_new_log(env, cathandle,
-                                                             next, NULL);
-                                       if (rc < 0)
-                                               cathandle->u.chd.chd_next_log =
-                                                               ERR_PTR(rc);
-                               }
-                               up_write(&next->lgh_lock);
-                               up_write(&cathandle->lgh_lock);
-                               if (rc < 0)
-                                       GOTO(out, rc);
-                       } else {
-                               rc = llog_declare_create(env, next, th);
-                               llog_declare_write_rec(env, cathandle,
-                                               &lirec->lid_hdr, -1, th);
-                       }
-               }
-               /* XXX: we hope for declarations made for existing llog
-                *      this might be not correct with some backends
-                *      where declarations are expected against specific
-                *      object like ZFS with full debugging enabled */
-               /*llog_declare_write_rec(env, next, rec, -1, th);*/
-       }
-out:
+#if 0
+       /*
+        * XXX: we hope for declarations made for existing llog this might be
+        * not correct with some backends where declarations are expected
+        * against specific object like ZFS with full debugging enabled.
+        */
+       rc = llog_declare_write_rec(env, cathandle->u.chd.chd_next_log, rec, -1,
+                                   th);
+#endif
+unlock:
+       up_read(&cathandle->lgh_lock);
        RETURN(rc);
 }
 EXPORT_SYMBOL(llog_cat_declare_add_rec);
@@ -722,6 +690,63 @@ out_trans:
 }
 EXPORT_SYMBOL(llog_cat_add);
 
+int llog_cat_cancel_arr_rec(const struct lu_env *env,
+                           struct llog_handle *cathandle,
+                           struct llog_logid *lgl, int count, int *index)
+{
+       struct llog_handle *loghandle;
+       int  rc;
+
+       ENTRY;
+       rc = llog_cat_id2handle(env, cathandle, &loghandle, lgl);
+       if (rc) {
+               CDEBUG(D_HA, "%s: cannot find llog for handle "DFID":%x"
+                      ": rc = %d\n",
+                      cathandle->lgh_ctxt->loc_obd->obd_name,
+                      PFID(&lgl->lgl_oi.oi_fid), lgl->lgl_ogen, rc);
+               RETURN(rc);
+       }
+
+       if ((cathandle->lgh_ctxt->loc_flags &
+            LLOG_CTXT_FLAG_NORMAL_FID) && !llog_exist(loghandle)) {
+               /* For update log, some of loghandles of cathandle
+                * might not exist because remote llog creation might
+                * be failed, so let's skip the record cancellation
+                * for these non-exist llogs.
+                */
+               rc = -ENOENT;
+               CDEBUG(D_HA, "%s: llog "DFID":%x does not exist"
+                      ": rc = %d\n",
+                      cathandle->lgh_ctxt->loc_obd->obd_name,
+                      PFID(&lgl->lgl_oi.oi_fid), lgl->lgl_ogen, rc);
+
+               llog_handle_put(loghandle);
+               RETURN(rc);
+       }
+
+       rc = llog_cancel_arr_rec(env, loghandle, count, index);
+       if (rc == LLOG_DEL_PLAIN) { /* log has been destroyed */
+               int cat_index;
+
+               cat_index = loghandle->u.phd.phd_cookie.lgc_index;
+               rc = llog_cat_cleanup(env, cathandle, loghandle, cat_index);
+               if (rc)
+                       CERROR("%s: fail to cancel catalog record: rc = %d\n",
+                              cathandle->lgh_ctxt->loc_obd->obd_name, rc);
+               rc = 0;
+
+       }
+       llog_handle_put(loghandle);
+
+       if (rc)
+               CERROR("%s: fail to cancel %d llog-records: rc = %d\n",
+                      cathandle->lgh_ctxt->loc_obd->obd_name, count,
+                      rc);
+
+       RETURN(rc);
+}
+EXPORT_SYMBOL(llog_cat_cancel_arr_rec);
+
 /* For each cookie in the cookie array, we clear the log in-use bit and either:
  * - the log is empty, so mark it free in the catalog header and delete it
  * - the log is not empty, just write out the log header
@@ -735,43 +760,25 @@ int llog_cat_cancel_records(const struct lu_env *env,
                            struct llog_handle *cathandle, int count,
                            struct llog_cookie *cookies)
 {
-       int i, index, rc = 0, failed = 0;
+       int i, rc = 0, failed = 0;
 
        ENTRY;
 
        for (i = 0; i < count; i++, cookies++) {
-               struct llog_handle *loghandle;
-               struct llog_logid *lgl = &cookies->lgc_lgl;
-               int  lrc;
-
-               rc = llog_cat_id2handle(env, cathandle, &loghandle, lgl);
-               if (rc) {
-                       CDEBUG(D_HA, "%s: cannot find llog for handle "DFID":%x"
-                              ": rc = %d\n",
-                              cathandle->lgh_ctxt->loc_obd->obd_name,
-                              PFID(&lgl->lgl_oi.oi_fid), lgl->lgl_ogen, rc);
-                       failed++;
-                       continue;
-               }
+               int lrc;
 
-               lrc = llog_cancel_rec(env, loghandle, cookies->lgc_index);
-               if (lrc == LLOG_DEL_PLAIN) { /* log has been destroyed */
-                       index = loghandle->u.phd.phd_cookie.lgc_index;
-                       rc = llog_cat_cleanup(env, cathandle, loghandle, index);
-               } else if (lrc == -ENOENT) {
-                       if (rc == 0) /* ENOENT shouldn't rewrite any error */
-                               rc = lrc;
-               } else if (lrc < 0) {
+               lrc = llog_cat_cancel_arr_rec(env, cathandle, &cookies->lgc_lgl,
+                                            1, &cookies->lgc_index);
+               if (lrc) {
                        failed++;
-                       rc = lrc;
+                       if (!rc)
+                               rc = lrc;
                }
-               llog_handle_put(loghandle);
        }
-       if (rc)
+       if (failed)
                CERROR("%s: fail to cancel %d of %d llog-records: rc = %d\n",
                       cathandle->lgh_ctxt->loc_obd->obd_name, failed, count,
                       rc);
-
        RETURN(rc);
 }
 EXPORT_SYMBOL(llog_cat_cancel_records);
@@ -806,9 +813,8 @@ static int llog_cat_process_common(const struct lu_env *env,
                 * deletion are not atomic. So we end up with an index but no
                 * actual record. Destroy the index and move on. */
                if (rc == -ENOENT || rc == -ESTALE)
-                       rc = llog_cat_cleanup(env, cat_llh, NULL,
-                                             rec->lrh_index);
-               if (rc)
+                       rc = LLOG_DEL_RECORD;
+               else if (rc)
                        CWARN("%s: can't find llog handle "DFID":%x: rc = %d\n",
                              cat_llh->lgh_ctxt->loc_obd->obd_name,
                              PFID(&lir->lid_id.lgl_oi.oi_fid),
@@ -866,9 +872,14 @@ static int llog_cat_process_cb(const struct lu_env *env,
 
 out:
        /* The empty plain log was destroyed while processing */
-       if (rc == LLOG_DEL_PLAIN)
+       if (rc == LLOG_DEL_PLAIN) {
                rc = llog_cat_cleanup(env, cat_llh, llh,
                                      llh->u.phd.phd_cookie.lgc_index);
+       } else if (rc == LLOG_DEL_RECORD) {
+               /* clear wrong catalog entry */
+               rc = llog_cat_cleanup(env, cat_llh, NULL, rec->lrh_index);
+       }
+
        if (llh)
                llog_handle_put(llh);
 
@@ -880,16 +891,17 @@ int llog_cat_process_or_fork(const struct lu_env *env,
                             llog_cb_t cb, void *data, int startcat,
                             int startidx, bool fork)
 {
-        struct llog_process_data d;
-        struct llog_log_hdr *llh = cat_llh->lgh_hdr;
-        int rc;
-        ENTRY;
+       struct llog_process_data d;
+       struct llog_log_hdr *llh = cat_llh->lgh_hdr;
+       int rc;
 
-        LASSERT(llh->llh_flags & LLOG_F_IS_CAT);
-        d.lpd_data = data;
-        d.lpd_cb = cb;
-        d.lpd_startcat = startcat;
-        d.lpd_startidx = startidx;
+       ENTRY;
+
+       LASSERT(llh->llh_flags & LLOG_F_IS_CAT);
+       d.lpd_data = data;
+       d.lpd_cb = cb;
+       d.lpd_startcat = (startcat == LLOG_CAT_FIRST ? 0 : startcat);
+       d.lpd_startidx = startidx;
 
        if (llh->llh_cat_idx >= cat_llh->lgh_last_idx &&
            llh->llh_count > 1) {
@@ -898,25 +910,43 @@ int llog_cat_process_or_fork(const struct lu_env *env,
                CWARN("%s: catlog "DFID" crosses index zero\n",
                      cat_llh->lgh_ctxt->loc_obd->obd_name,
                      PFID(&cat_llh->lgh_id.lgl_oi.oi_fid));
-
-               cd.lpcd_first_idx = llh->llh_cat_idx;
-               cd.lpcd_last_idx = 0;
-               rc = llog_process_or_fork(env, cat_llh, cat_cb,
-                                         &d, &cd, fork);
-               if (rc != 0)
-                       RETURN(rc);
-
-               cd.lpcd_first_idx = 0;
+               /*startcat = 0 is default value for general processing */
+               if ((startcat != LLOG_CAT_FIRST &&
+                   startcat >= llh->llh_cat_idx) || !startcat) {
+                       /* processing the catalog part at the end */
+                       cd.lpcd_first_idx = (startcat ? startcat :
+                                            llh->llh_cat_idx);
+                       if (OBD_FAIL_PRECHECK(OBD_FAIL_CAT_RECORDS))
+                               cd.lpcd_last_idx = cfs_fail_val;
+                       else
+                               cd.lpcd_last_idx = 0;
+                       rc = llog_process_or_fork(env, cat_llh, cat_cb,
+                                                 &d, &cd, fork);
+                       /* Reset the startcat becasue it has already reached
+                        * catalog bottom.
+                        */
+                       startcat = 0;
+                       if (rc != 0)
+                               RETURN(rc);
+               }
+               /* processing the catalog part at the begining */
+               cd.lpcd_first_idx = (startcat == LLOG_CAT_FIRST) ? 0 : startcat;
+               /* Note, the processing will stop at the lgh_last_idx value,
+                * and it could be increased during processing. So records
+                * between current lgh_last_idx and lgh_last_idx in future
+                * would left unprocessed.
+                */
                cd.lpcd_last_idx = cat_llh->lgh_last_idx;
                rc = llog_process_or_fork(env, cat_llh, cat_cb,
                                          &d, &cd, fork);
-        } else {
+       } else {
                rc = llog_process_or_fork(env, cat_llh, cat_cb,
                                          &d, NULL, fork);
-        }
+       }
 
-        RETURN(rc);
+       RETURN(rc);
 }
+EXPORT_SYMBOL(llog_cat_process_or_fork);
 
 int llog_cat_process(const struct lu_env *env, struct llog_handle *cat_llh,
                     llog_cb_t cb, void *data, int startcat, int startidx)
@@ -938,13 +968,14 @@ static int llog_cat_size_cb(const struct lu_env *env,
 
        ENTRY;
        rc = llog_cat_process_common(env, cat_llh, rec, &llh);
-       if (llh == NULL)
-               RETURN(0);
 
        if (rc == LLOG_DEL_PLAIN) {
                /* empty log was deleted, don't count it */
                rc = llog_cat_cleanup(env, cat_llh, llh,
                                      llh->u.phd.phd_cookie.lgc_index);
+       } else if (rc == LLOG_DEL_RECORD) {
+               /* clear wrong catalog entry */
+               rc = llog_cat_cleanup(env, cat_llh, NULL, rec->lrh_index);
        } else {
                size = llog_size(env, llh);
                *cum_size += size;
@@ -953,7 +984,8 @@ static int llog_cat_size_cb(const struct lu_env *env,
                       PFID(&llh->lgh_id.lgl_oi.oi_fid), size, *cum_size);
        }
 
-       llog_handle_put(llh);
+       if (llh != NULL)
+               llog_handle_put(llh);
 
        RETURN(0);
 }
@@ -969,6 +1001,28 @@ __u64 llog_cat_size(const struct lu_env *env, struct llog_handle *cat_llh)
 }
 EXPORT_SYMBOL(llog_cat_size);
 
+/* currently returns the number of "free" entries in catalog,
+ * ie the available entries for a new plain LLOG file creation,
+ * even if catalog has wrapped
+ */
+__u32 llog_cat_free_space(struct llog_handle *cat_llh)
+{
+       /* simulate almost full Catalog */
+       if (OBD_FAIL_CHECK(OBD_FAIL_CAT_FREE_RECORDS))
+               return cfs_fail_val;
+
+       if (cat_llh->lgh_hdr->llh_count == 1)
+               return LLOG_HDR_BITMAP_SIZE(cat_llh->lgh_hdr) - 1;
+
+       if (cat_llh->lgh_last_idx > cat_llh->lgh_hdr->llh_cat_idx)
+               return LLOG_HDR_BITMAP_SIZE(cat_llh->lgh_hdr) - 1 +
+                      cat_llh->lgh_hdr->llh_cat_idx - cat_llh->lgh_last_idx;
+
+       /* catalog is presently wrapped */
+       return cat_llh->lgh_hdr->llh_cat_idx - cat_llh->lgh_last_idx;
+}
+EXPORT_SYMBOL(llog_cat_free_space);
+
 static int llog_cat_reverse_process_cb(const struct lu_env *env,
                                       struct llog_handle *cat_llh,
                                       struct llog_rec_hdr *rec, void *data)
@@ -979,6 +1033,15 @@ static int llog_cat_reverse_process_cb(const struct lu_env *env,
 
        ENTRY;
        rc = llog_cat_process_common(env, cat_llh, rec, &llh);
+
+       /* The empty plain log was destroyed while processing */
+       if (rc == LLOG_DEL_PLAIN) {
+               rc = llog_cat_cleanup(env, cat_llh, llh,
+                                     llh->u.phd.phd_cookie.lgc_index);
+       } else if (rc == LLOG_DEL_RECORD) {
+               /* clear wrong catalog entry */
+               rc = llog_cat_cleanup(env, cat_llh, NULL, rec->lrh_index);
+       }
        if (rc)
                RETURN(rc);