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LU-10198 llog: keep llog handle alive until last reference
[fs/lustre-release.git] / lustre / obdclass / llog.c
index 334f752..8a24d05 100644 (file)
  *
  * 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
  */
@@ -27,7 +23,7 @@
  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
  *
- * Copyright (c) 2012, 2014, Intel Corporation.
+ * Copyright (c) 2012, 2017, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
 
 #define DEBUG_SUBSYSTEM S_LOG
 
+#include <linux/pid_namespace.h>
 #include <linux/kthread.h>
-#include <obd_class.h>
+#include <llog_swab.h>
 #include <lustre_log.h>
+#include <obd_support.h>
+#include <obd_class.h>
 #include "llog_internal.h"
-
 /*
  * Allocate a new log or catalog handle
  * Used inside llog_open().
@@ -66,8 +64,9 @@ static struct llog_handle *llog_alloc_handle(void)
 
        init_rwsem(&loghandle->lgh_lock);
        mutex_init(&loghandle->lgh_hdr_mutex);
+       init_rwsem(&loghandle->lgh_last_sem);
        INIT_LIST_HEAD(&loghandle->u.phd.phd_entry);
-       atomic_set(&loghandle->lgh_refcount, 1);
+       refcount_set(&loghandle->lgh_refcount, 1);
 
        return loghandle;
 }
@@ -92,123 +91,256 @@ out:
        OBD_FREE_PTR(loghandle);
 }
 
-void llog_handle_get(struct llog_handle *loghandle)
+struct llog_handle *llog_handle_get(struct llog_handle *loghandle)
 {
-       atomic_inc(&loghandle->lgh_refcount);
+       if (refcount_inc_not_zero(&loghandle->lgh_refcount))
+               return loghandle;
+       return NULL;
 }
 
-void llog_handle_put(struct llog_handle *loghandle)
+int llog_handle_put(const struct lu_env *env, struct llog_handle *loghandle)
 {
-       LASSERT(atomic_read(&loghandle->lgh_refcount) > 0);
-       if (atomic_dec_and_test(&loghandle->lgh_refcount))
+       int rc = 0;
+
+       if (refcount_dec_and_test(&loghandle->lgh_refcount)) {
+               struct llog_operations *lop;
+
+               rc = llog_handle2ops(loghandle, &lop);
+               if (!rc) {
+                       if (lop->lop_close)
+                               rc = lop->lop_close(env, loghandle);
+                       else
+                               rc = -EOPNOTSUPP;
+               }
                llog_free_handle(loghandle);
+       }
+       return rc;
+}
+
+static int llog_declare_destroy(const struct lu_env *env,
+                               struct llog_handle *handle,
+                               struct thandle *th)
+{
+       struct llog_operations *lop;
+       int rc;
+
+       ENTRY;
+
+       rc = llog_handle2ops(handle, &lop);
+       if (rc)
+               RETURN(rc);
+       if (lop->lop_declare_destroy == NULL)
+               RETURN(-EOPNOTSUPP);
+
+       rc = lop->lop_declare_destroy(env, handle, th);
+
+       RETURN(rc);
+}
+
+int llog_trans_destroy(const struct lu_env *env, struct llog_handle *handle,
+                      struct thandle *th)
+{
+       struct llog_operations  *lop;
+       int rc;
+       ENTRY;
+
+       rc = llog_handle2ops(handle, &lop);
+       if (rc < 0)
+               RETURN(rc);
+       if (lop->lop_destroy == NULL)
+               RETURN(-EOPNOTSUPP);
+
+       LASSERT(handle->lgh_obj != NULL);
+       if (!llog_exist(handle))
+               RETURN(0);
+
+       rc = lop->lop_destroy(env, handle, th);
+
+       RETURN(rc);
 }
 
-static int llog_cancel_rec_internal(const struct lu_env *env,
-                                   struct llog_handle *loghandle, int index)
+int llog_destroy(const struct lu_env *env, struct llog_handle *handle)
 {
+       struct llog_operations  *lop;
        struct dt_device        *dt;
-       struct llog_log_hdr     *llh = loghandle->lgh_hdr;
        struct thandle          *th;
-       int                      rc;
+       int rc;
 
        ENTRY;
 
-       LASSERT(loghandle);
-       LASSERT(loghandle->lgh_ctxt);
-       LASSERT(loghandle->lgh_obj != NULL);
+       rc = llog_handle2ops(handle, &lop);
+       if (rc < 0)
+               RETURN(rc);
+       if (lop->lop_destroy == NULL)
+               RETURN(-EOPNOTSUPP);
 
-       dt = lu2dt_dev(loghandle->lgh_obj->do_lu.lo_dev);
+       if (handle->lgh_obj == NULL) {
+               /* if lgh_obj == NULL, then it is from client side destroy */
+               rc = lop->lop_destroy(env, handle, NULL);
+               RETURN(rc);
+       }
+
+       if (!llog_exist(handle))
+               RETURN(0);
+
+       dt = lu2dt_dev(handle->lgh_obj->do_lu.lo_dev);
+
+       if (unlikely(unlikely(dt->dd_rdonly)))
+               RETURN(-EROFS);
 
        th = dt_trans_create(env, dt);
        if (IS_ERR(th))
                RETURN(PTR_ERR(th));
 
-       rc = llog_declare_write_rec(env, loghandle, &llh->llh_hdr, index, th);
-       if (rc < 0)
+       rc = llog_declare_destroy(env, handle, th);
+       if (rc != 0)
                GOTO(out_trans, rc);
 
-       th->th_wait_submit = 1;
        rc = dt_trans_start_local(env, dt, th);
        if (rc < 0)
                GOTO(out_trans, rc);
 
-       down_write(&loghandle->lgh_lock);
-       /* clear bitmap */
-       mutex_lock(&loghandle->lgh_hdr_mutex);
-       if (!ext2_clear_bit(index, LLOG_HDR_BITMAP(llh))) {
-               CDEBUG(D_RPCTRACE, "Catalog index %u already clear?\n", index);
-               GOTO(out_unlock, rc);
-       }
-       /* update header */
-       rc = llog_write_rec(env, loghandle, &llh->llh_hdr, NULL,
-                           LLOG_HEADER_IDX, th);
-       if (rc == 0)
-               loghandle->lgh_hdr->llh_count--;
-       else
-               ext2_set_bit(index, LLOG_HDR_BITMAP(llh));
-out_unlock:
-       mutex_unlock(&loghandle->lgh_hdr_mutex);
-       up_write(&loghandle->lgh_lock);
+       rc = lop->lop_destroy(env, handle, th);
+
 out_trans:
        dt_trans_stop(env, dt, th);
+
        RETURN(rc);
 }
+EXPORT_SYMBOL(llog_destroy);
 
 /* returns negative on error; 0 if success; 1 if success & log destroyed */
-int llog_cancel_rec(const struct lu_env *env, struct llog_handle *loghandle,
-                   int index)
+int llog_cancel_arr_rec(const struct lu_env *env, struct llog_handle *loghandle,
+                       int num, int *index)
 {
-        struct llog_log_hdr *llh = loghandle->lgh_hdr;
-        int rc = 0;
-        ENTRY;
+       struct llog_thread_info *lgi = llog_info(env);
+       struct dt_device        *dt;
+       struct llog_log_hdr     *llh;
+       struct thandle          *th;
+       __u32                    tmp_lgc_index;
+       int                      rc, i = 0;
+       int rc1;
+       bool subtract_count = false;
 
-        CDEBUG(D_RPCTRACE, "Canceling %d in log "DOSTID"\n",
-               index, POSTID(&loghandle->lgh_id.lgl_oi));
+       ENTRY;
 
-        if (index == 0) {
-                CERROR("Can't cancel index 0 which is header\n");
-                RETURN(-EINVAL);
-        }
+       LASSERT(loghandle != NULL);
+       LASSERT(loghandle->lgh_ctxt != NULL);
+       LASSERT(loghandle->lgh_obj != NULL);
 
-       rc = llog_cancel_rec_internal(env, loghandle, index);
-       if (rc < 0) {
-               CERROR("%s: fail to write header for llog #"DOSTID
-                      "#%08x: rc = %d\n",
-                      loghandle->lgh_ctxt->loc_obd->obd_name,
-                      POSTID(&loghandle->lgh_id.lgl_oi),
-                      loghandle->lgh_id.lgl_ogen, rc);
-               RETURN(rc);
+       llh = loghandle->lgh_hdr;
+
+       CDEBUG(D_RPCTRACE, "Canceling %d records, first %d in log "DFID"\n",
+              num, index[0], PFID(&loghandle->lgh_id.lgl_oi.oi_fid));
+
+       dt = lu2dt_dev(loghandle->lgh_obj->do_lu.lo_dev);
+
+       if (unlikely(unlikely(dt->dd_rdonly)))
+               RETURN(0);
+
+       th = dt_trans_create(env, dt);
+       if (IS_ERR(th))
+               RETURN(PTR_ERR(th));
+
+       rc = llog_declare_write_rec(env, loghandle, &llh->llh_hdr, 0, th);
+       if (rc < 0)
+               GOTO(out_trans, rc);
+
+       if ((llh->llh_flags & LLOG_F_ZAP_WHEN_EMPTY)) {
+               rc = llog_declare_destroy(env, loghandle, th);
+               if (rc < 0)
+                       GOTO(out_trans, rc);
        }
 
+       th->th_wait_submit = 1;
+       rc = dt_trans_start_local(env, dt, th);
+       if (rc < 0)
+               GOTO(out_trans, rc);
+
+       down_write(&loghandle->lgh_lock);
+       /* clear bitmap */
+       mutex_lock(&loghandle->lgh_hdr_mutex);
+       for (i = 0; i < num; ++i) {
+               if (index[i] == 0) {
+                       CERROR("Can't cancel index 0 which is header\n");
+                       GOTO(out_unlock, rc = -EINVAL);
+               }
+               if (!ext2_clear_bit(index[i], LLOG_HDR_BITMAP(llh))) {
+                       CDEBUG(D_RPCTRACE, "Catalog index %u already clear?\n",
+                              index[i]);
+                       GOTO(out_unlock, rc = -ENOENT);
+               }
+       }
+       loghandle->lgh_hdr->llh_count -= num;
+       subtract_count = true;
+
+       /* Since llog_process_thread use lgi_cookie, it`s better to save them
+        * and restore after using
+        */
+       tmp_lgc_index = lgi->lgi_cookie.lgc_index;
+       /* Pass this index to llog_osd_write_rec(), which will use the index
+        * to only update the necesary bitmap. */
+       lgi->lgi_cookie.lgc_index = index[0];
+       /* update header */
+       rc = llog_write_rec(env, loghandle, &llh->llh_hdr, (num != 1 ? NULL :
+                           &lgi->lgi_cookie), LLOG_HEADER_IDX, th);
+       lgi->lgi_cookie.lgc_index = tmp_lgc_index;
+
+       if (rc != 0)
+               GOTO(out_unlock, rc);
+
        if ((llh->llh_flags & LLOG_F_ZAP_WHEN_EMPTY) &&
            (llh->llh_count == 1) &&
-           (loghandle->lgh_last_idx == LLOG_HDR_BITMAP_SIZE(llh) - 1)) {
-               rc = llog_destroy(env, loghandle);
+           ((loghandle->lgh_last_idx == LLOG_HDR_BITMAP_SIZE(llh) - 1) ||
+            (loghandle->u.phd.phd_cat_handle != NULL &&
+             loghandle->u.phd.phd_cat_handle->u.chd.chd_current_log !=
+               loghandle))) {
+               /* never try to destroy it again */
+               llh->llh_flags &= ~LLOG_F_ZAP_WHEN_EMPTY;
+               rc = llog_trans_destroy(env, loghandle, th);
                if (rc < 0) {
                        /* Sigh, can not destroy the final plain llog, but
                         * the bitmap has been clearly, so the record can not
                         * be accessed anymore, let's return 0 for now, and
                         * the orphan will be handled by LFSCK. */
-                       CERROR("%s: can't destroy empty llog #"DOSTID
-                              "#%08x: rc = %d\n",
+                       CERROR("%s: can't destroy empty llog "DFID": rc = %d\n",
                               loghandle->lgh_ctxt->loc_obd->obd_name,
-                              POSTID(&loghandle->lgh_id.lgl_oi),
-                              loghandle->lgh_id.lgl_ogen, rc);
-                       RETURN(0);
+                              PFID(&loghandle->lgh_id.lgl_oi.oi_fid), rc);
+                       GOTO(out_unlock, rc = 0);
                }
-               RETURN(LLOG_DEL_PLAIN);
+               rc = LLOG_DEL_PLAIN;
+       }
+
+out_unlock:
+       mutex_unlock(&loghandle->lgh_hdr_mutex);
+       up_write(&loghandle->lgh_lock);
+out_trans:
+       rc1 = dt_trans_stop(env, dt, th);
+       if (rc == 0)
+               rc = rc1;
+       if (rc < 0) {
+               mutex_lock(&loghandle->lgh_hdr_mutex);
+               if (subtract_count)
+                       loghandle->lgh_hdr->llh_count += num;
+               for (i = i - 1; i >= 0; i--)
+                       ext2_set_bit(index[i], LLOG_HDR_BITMAP(llh));
+               mutex_unlock(&loghandle->lgh_hdr_mutex);
        }
+       RETURN(rc);
+}
 
-       RETURN(0);
+int llog_cancel_rec(const struct lu_env *env, struct llog_handle *loghandle,
+                   int index)
+{
+       return llog_cancel_arr_rec(env, loghandle, 1, &index);
 }
 
-static int llog_read_header(const struct lu_env *env,
-                           struct llog_handle *handle,
-                           struct obd_uuid *uuid)
+int llog_read_header(const struct lu_env *env, struct llog_handle *handle,
+                    const struct obd_uuid *uuid)
 {
        struct llog_operations *lop;
        int rc;
+       ENTRY;
 
        rc = llog_handle2ops(handle, &lop);
        if (rc)
@@ -229,18 +361,24 @@ static int llog_read_header(const struct lu_env *env,
                                                LLOG_MIN_CHUNK_SIZE);
                llh->llh_hdr.lrh_len = handle->lgh_ctxt->loc_chunk_size;
                llh->llh_hdr.lrh_index = 0;
-               llh->llh_timestamp = cfs_time_current_sec();
+               llh->llh_timestamp = ktime_get_real_seconds();
                if (uuid)
                        memcpy(&llh->llh_tgtuuid, uuid,
                               sizeof(llh->llh_tgtuuid));
                llh->llh_bitmap_offset = offsetof(typeof(*llh), llh_bitmap);
+               /* Since update llog header might also call this function,
+                * let's reset the bitmap to 0 here */
+               memset(LLOG_HDR_BITMAP(llh), 0, llh->llh_hdr.lrh_len -
+                                               llh->llh_bitmap_offset -
+                                               sizeof(llh->llh_tail));
                ext2_set_bit(0, LLOG_HDR_BITMAP(llh));
                LLOG_HDR_TAIL(llh)->lrt_len = llh->llh_hdr.lrh_len;
                LLOG_HDR_TAIL(llh)->lrt_index = llh->llh_hdr.lrh_index;
                rc = 0;
        }
-       return rc;
+       RETURN(rc);
 }
+EXPORT_SYMBOL(llog_read_header);
 
 int llog_init_handle(const struct lu_env *env, struct llog_handle *handle,
                     int flags, struct obd_uuid *uuid)
@@ -299,6 +437,7 @@ int llog_init_handle(const struct lu_env *env, struct llog_handle *handle,
                LASSERT(list_empty(&handle->u.chd.chd_head));
                INIT_LIST_HEAD(&handle->u.chd.chd_head);
                llh->llh_size = sizeof(struct llog_logid_rec);
+               llh->llh_flags |= LLOG_F_IS_FIXSIZE;
        } else if (!(flags & LLOG_F_IS_PLAIN)) {
                CERROR("%s: unknown flags: %#x (expected %#x or %#x)\n",
                       handle->lgh_ctxt->loc_obd->obd_name,
@@ -321,18 +460,22 @@ static int llog_process_thread(void *arg)
        struct llog_handle              *loghandle = lpi->lpi_loghandle;
        struct llog_log_hdr             *llh = loghandle->lgh_hdr;
        struct llog_process_cat_data    *cd  = lpi->lpi_catdata;
+       struct llog_thread_info         *lti;
        char                            *buf;
        size_t                           chunk_size;
        __u64                            cur_offset;
        int                              rc = 0, index = 1, last_index;
        int                              saved_index = 0;
        int                              last_called_index = 0;
+       bool                             repeated = false;
 
        ENTRY;
 
        if (llh == NULL)
                RETURN(-EINVAL);
 
+       lti = lpi->lpi_env == NULL ? NULL : llog_info(lpi->lpi_env);
+
        cur_offset = chunk_size = llh->llh_hdr.lrh_len;
        /* expect chunk_size to be power of two */
        LASSERT(is_power_of_2(chunk_size));
@@ -354,9 +497,11 @@ static int llog_process_thread(void *arg)
 
        while (rc == 0) {
                struct llog_rec_hdr *rec;
-               off_t chunk_offset;
+               off_t chunk_offset = 0;
                unsigned int buf_offset = 0;
                bool partial_chunk;
+               int     lh_last_idx;
+               int     synced_idx = 0;
 
                /* skip records not set in bitmap */
                while (index <= last_index &&
@@ -373,8 +518,20 @@ static int llog_process_thread(void *arg)
 repeat:
                /* get the buf with our target record; avoid old garbage */
                memset(buf, 0, chunk_size);
+               /* the record index for outdated chunk data */
+               /* it is safe to process buffer until saved lgh_last_idx */
+               lh_last_idx = LLOG_HDR_TAIL(llh)->lrt_index;
                rc = llog_next_block(lpi->lpi_env, loghandle, &saved_index,
                                     index, &cur_offset, buf, chunk_size);
+               if (repeated && rc)
+                       CDEBUG(D_OTHER, "cur_offset %llu, chunk_offset %llu,"
+                              " buf_offset %u, rc = %d\n", cur_offset,
+                              (__u64)chunk_offset, buf_offset, rc);
+               /* we`ve tried to reread the chunk, but there is no
+                * new records */
+               if (rc == -EIO && repeated && (chunk_offset + buf_offset) ==
+                   cur_offset)
+                       GOTO(out, rc = 0);
                if (rc != 0)
                        GOTO(out, rc);
 
@@ -383,7 +540,7 @@ repeat:
                 * The absolute offset of the current chunk is calculated
                 * from cur_offset value and stored in chunk_offset variable.
                 */
-               if (cur_offset % chunk_size != 0) {
+               if ((cur_offset & (chunk_size - 1)) != 0) {
                        partial_chunk = true;
                        chunk_offset = cur_offset & ~(chunk_size - 1);
                } else {
@@ -407,28 +564,61 @@ repeat:
                        CDEBUG(D_OTHER, "after swabbing, type=%#x idx=%d\n",
                               rec->lrh_type, rec->lrh_index);
 
-                       /* for partial chunk the end of it is zeroed, check
-                        * for index 0 to distinguish it. */
-                       if (partial_chunk && rec->lrh_index == 0) {
-                               /* concurrent llog_add() might add new records
-                                * while llog_processing, check this is not
-                                * the case and re-read the current chunk
-                                * otherwise. */
-                               if (index > loghandle->lgh_last_idx)
-                                       GOTO(out, rc = 0);
-                               CDEBUG(D_OTHER, "Re-read last llog buffer for "
-                                      "new records, index %u, last %u\n",
-                                      index, loghandle->lgh_last_idx);
+                       if (index == (synced_idx + 1) &&
+                           synced_idx == LLOG_HDR_TAIL(llh)->lrt_index)
+                               GOTO(out, rc = 0);
+
+                       if (OBD_FAIL_PRECHECK(OBD_FAIL_LLOG_PROCESS_TIMEOUT) &&
+                               cfs_fail_val == (unsigned int)
+                                       (loghandle->lgh_id.lgl_oi.oi.oi_id &
+                                        0xFFFFFFFF)) {
+                               OBD_RACE(OBD_FAIL_LLOG_PROCESS_TIMEOUT);
+                       }
+
+                       /* the bitmap could be changed during processing
+                        * records from the chunk. For wrapped catalog
+                        * it means we can read deleted record and try to
+                        * process it. Check this case and reread the chunk.
+                        * It is safe to process to lh_last_idx, including
+                        * lh_last_idx if it was synced. We can not do <=
+                        * comparison, cause for wrapped catalog lgh_last_idx
+                        * could be less than index. So we detect last index
+                        * for processing as index == lh_last_idx+1. But when
+                        * catalog is wrapped and full lgh_last_idx=llh_cat_idx,
+                        * the first processing index is llh_cat_idx+1.
+                        */
+
+                       if ((index == lh_last_idx && synced_idx != index) ||
+                           (index == (lh_last_idx + 1) &&
+                            !(index == (llh->llh_cat_idx + 1) &&
+                              (llh->llh_flags & LLOG_F_IS_CAT))) ||
+                           (rec->lrh_index == 0 && !repeated)) {
+
                                /* save offset inside buffer for the re-read */
                                buf_offset = (char *)rec - (char *)buf;
                                cur_offset = chunk_offset;
+                               repeated = true;
+                               /* We need to be sure lgh_last_idx
+                                * record was saved to disk
+                                */
+                               down_read(&loghandle->lgh_last_sem);
+                               synced_idx = LLOG_HDR_TAIL(llh)->lrt_index;
+                               up_read(&loghandle->lgh_last_sem);
+                               CDEBUG(D_OTHER, "synced_idx: %d\n", synced_idx);
                                goto repeat;
+
                        }
 
+                       repeated = false;
+
                        if (rec->lrh_len == 0 || rec->lrh_len > chunk_size) {
-                               CWARN("invalid length %d in llog record for "
-                                     "index %d/%d\n", rec->lrh_len,
-                                     rec->lrh_index, index);
+                               CWARN("%s: invalid length %d in llog "DFID
+                                     "record for index %d/%d\n",
+                                      loghandle->lgh_ctxt->loc_obd->obd_name,
+                                      rec->lrh_len,
+                                      PFID(&loghandle->lgh_id.lgl_oi.oi_fid),
+                                      rec->lrh_index, index);
+
                                GOTO(out, rc = -EINVAL);
                        }
 
@@ -439,9 +629,10 @@ repeat:
                        }
 
                        if (rec->lrh_index != index) {
-                               CERROR("%s: Invalid record: index %u but "
-                                      "expected %u\n",
+                               CERROR("%s: "DFID" Invalid record: index %u"
+                                      " but expected %u\n",
                                       loghandle->lgh_ctxt->loc_obd->obd_name,
+                                      PFID(&loghandle->lgh_id.lgl_oi.oi_fid),
                                       rec->lrh_index, index);
                                GOTO(out, rc = -ERANGE);
                        }
@@ -451,15 +642,42 @@ repeat:
                               rec->lrh_index, rec->lrh_len,
                               (int)(buf + chunk_size - (char *)rec));
 
-                       loghandle->lgh_cur_idx = rec->lrh_index;
+                       /* lgh_cur_offset is used only at llog_test_3 */
                        loghandle->lgh_cur_offset = (char *)rec - (char *)buf +
                                                    chunk_offset;
 
                        /* if set, process the callback on this record */
                        if (ext2_test_bit(index, LLOG_HDR_BITMAP(llh))) {
+                               struct llog_cookie *lgc;
+                               __u64   tmp_off;
+                               int     tmp_idx;
+
+                               CDEBUG(D_OTHER, "index: %d, lh_last_idx: %d "
+                                      "synced_idx: %d lgh_last_idx: %d\n",
+                                      index, lh_last_idx, synced_idx,
+                                      loghandle->lgh_last_idx);
+
+                               if (lti != NULL) {
+                                       lgc = &lti->lgi_cookie;
+                                       /* store lu_env for recursive calls */
+                                       tmp_off = lgc->lgc_offset;
+                                       tmp_idx = lgc->lgc_index;
+
+                                       lgc->lgc_offset = (char *)rec -
+                                               (char *)buf + chunk_offset;
+                                       lgc->lgc_index = rec->lrh_index;
+                               }
+                               /* using lu_env for passing record offset to
+                                * llog_write through various callbacks */
                                rc = lpi->lpi_cb(lpi->lpi_env, loghandle, rec,
                                                 lpi->lpi_cbdata);
                                last_called_index = index;
+
+                               if (lti != NULL) {
+                                       lgc->lgc_offset = tmp_off;
+                                       lgc->lgc_index = tmp_idx;
+                               }
+
                                if (rc == LLOG_PROC_BREAK) {
                                        GOTO(out, rc);
                                } else if (rc == LLOG_DEL_RECORD) {
@@ -469,6 +687,12 @@ repeat:
                                }
                                if (rc)
                                        GOTO(out, rc);
+                               /* some stupid callbacks directly cancel records
+                                * and delete llog. Check it and stop
+                                * processing. */
+                               if (loghandle->lgh_hdr == NULL ||
+                                   loghandle->lgh_hdr->llh_count == 1)
+                                       GOTO(out, rc = 0);
                        }
                        /* exit if the last index is reached */
                        if (index >= last_index)
@@ -482,22 +706,42 @@ out:
                cd->lpcd_last_idx = last_called_index;
 
        if (unlikely(rc == -EIO && loghandle->lgh_obj != NULL)) {
-               /* something bad happened to the processing of a local
-                * llog file, probably I/O error or the log got corrupted..
-                * to be able to finally release the log we discard any
-                * remaining bits in the header */
-               CERROR("Local llog found corrupted\n");
-               while (index <= last_index) {
-                       if (ext2_test_bit(index, LLOG_HDR_BITMAP(llh)) != 0)
-                               llog_cancel_rec(lpi->lpi_env, loghandle, index);
-                       index++;
+               if (dt_object_remote(loghandle->lgh_obj)) {
+                       /* If it is remote object, then -EIO might means
+                        * disconnection or eviction, let's return -EAGAIN,
+                        * so for update recovery log processing, it will
+                        * retry until the umount or abort recovery, see
+                        * lod_sub_recovery_thread() */
+                       CERROR("%s retry remote llog process\n",
+                              loghandle->lgh_ctxt->loc_obd->obd_name);
+                       rc = -EAGAIN;
+               } else {
+                       /* something bad happened to the processing of a local
+                        * llog file, probably I/O error or the log got
+                        * corrupted to be able to finally release the log we
+                        * discard any remaining bits in the header */
+                       CERROR("%s: Local llog found corrupted #"DOSTID":%x"
+                              " %s index %d count %d\n",
+                              loghandle->lgh_ctxt->loc_obd->obd_name,
+                              POSTID(&loghandle->lgh_id.lgl_oi),
+                              loghandle->lgh_id.lgl_ogen,
+                              ((llh->llh_flags & LLOG_F_IS_CAT) ? "catalog" :
+                               "plain"), index, llh->llh_count);
+
+                       while (index <= last_index) {
+                               if (ext2_test_bit(index,
+                                                 LLOG_HDR_BITMAP(llh)) != 0)
+                                       llog_cancel_rec(lpi->lpi_env, loghandle,
+                                                       index);
+                               index++;
+                       }
+                       rc = 0;
                }
-               rc = 0;
        }
 
        OBD_FREE_LARGE(buf, chunk_size);
-        lpi->lpi_rc = rc;
-        return 0;
+       lpi->lpi_rc = rc;
+       return 0;
 }
 
 static int llog_process_thread_daemonize(void *arg)
@@ -505,6 +749,23 @@ static int llog_process_thread_daemonize(void *arg)
        struct llog_process_info        *lpi = arg;
        struct lu_env                    env;
        int                              rc;
+       struct nsproxy                  *new_ns, *curr_ns = current->nsproxy;
+
+       task_lock(lpi->lpi_reftask);
+       new_ns = lpi->lpi_reftask->nsproxy;
+       if (curr_ns != new_ns) {
+               get_nsproxy(new_ns);
+
+               current->nsproxy = new_ns;
+               /* XXX: we should call put_nsproxy() instead of
+                * atomic_dec(&ns->count) directly. But put_nsproxy() cannot be
+                * used outside of the kernel itself, because it calls
+                * free_nsproxy() which is not exported by the kernel
+                * (defined in kernel/nsproxy.c) */
+               if (curr_ns)
+                       atomic_dec(&curr_ns->count);
+       }
+       task_unlock(lpi->lpi_reftask);
 
        unshare_fs_struct();
 
@@ -526,21 +787,28 @@ int llog_process_or_fork(const struct lu_env *env,
                         struct llog_handle *loghandle,
                         llog_cb_t cb, void *data, void *catdata, bool fork)
 {
-        struct llog_process_info *lpi;
-        int                      rc;
-
-        ENTRY;
+       struct llog_process_info *lpi;
+       struct llog_process_data *d = data;
+       struct llog_process_cat_data *cd = catdata;
+       int                      rc;
 
-        OBD_ALLOC_PTR(lpi);
-        if (lpi == NULL) {
-                CERROR("cannot alloc pointer\n");
-                RETURN(-ENOMEM);
-        }
-        lpi->lpi_loghandle = loghandle;
-        lpi->lpi_cb        = cb;
-        lpi->lpi_cbdata    = data;
-        lpi->lpi_catdata   = catdata;
+       ENTRY;
 
+       OBD_ALLOC_PTR(lpi);
+       if (lpi == NULL) {
+               CERROR("cannot alloc pointer\n");
+               RETURN(-ENOMEM);
+       }
+       lpi->lpi_loghandle = loghandle;
+       lpi->lpi_cb        = cb;
+       lpi->lpi_cbdata    = data;
+       lpi->lpi_catdata   = catdata;
+
+       CDEBUG(D_OTHER, "Processing "DFID" flags 0x%03x startcat %d startidx %d first_idx %d last_idx %d\n",
+              PFID(&loghandle->lgh_id.lgl_oi.oi_fid),
+              loghandle->lgh_hdr->llh_flags, d ? d->lpd_startcat : -1,
+              d ? d->lpd_startidx : -1, cd ? cd->lpcd_first_idx : -1,
+              cd ? cd->lpcd_last_idx : -1);
        if (fork) {
                struct task_struct *task;
 
@@ -548,6 +816,10 @@ int llog_process_or_fork(const struct lu_env *env,
                 * init the new one in llog_process_thread_daemonize. */
                lpi->lpi_env = NULL;
                init_completion(&lpi->lpi_completion);
+               /* take reference to current, so that
+                * llog_process_thread_daemonize() can use it to switch to
+                * namespace associated with current  */
+               lpi->lpi_reftask = current;
                task = kthread_run(llog_process_thread_daemonize, lpi,
                                   "llog_process_thread");
                if (IS_ERR(task)) {
@@ -578,6 +850,27 @@ int llog_process(const struct lu_env *env, struct llog_handle *loghandle,
 }
 EXPORT_SYMBOL(llog_process);
 
+static inline const struct cred *llog_raise_resource(void)
+{
+       struct cred *cred = NULL;
+
+       if (cap_raised(current_cap(), CAP_SYS_RESOURCE))
+               return cred;
+
+       cred = prepare_creds();
+       if (!cred)
+               return cred;
+
+       cap_raise(cred->cap_effective, CAP_SYS_RESOURCE);
+       return override_creds(cred);
+}
+
+static inline void llog_restore_resource(const struct cred *old_cred)
+{
+       if (old_cred)
+               revert_creds(old_cred);
+}
+
 int llog_reverse_process(const struct lu_env *env,
                         struct llog_handle *loghandle, llog_cb_t cb,
                         void *data, void *catdata)
@@ -702,8 +995,9 @@ EXPORT_SYMBOL(llog_exist);
 int llog_declare_create(const struct lu_env *env,
                        struct llog_handle *loghandle, struct thandle *th)
 {
+       const struct cred *old_cred;
        struct llog_operations  *lop;
-       int                      raised, rc;
+       int rc;
 
        ENTRY;
 
@@ -713,20 +1007,18 @@ int llog_declare_create(const struct lu_env *env,
        if (lop->lop_declare_create == NULL)
                RETURN(-EOPNOTSUPP);
 
-       raised = cfs_cap_raised(CFS_CAP_SYS_RESOURCE);
-       if (!raised)
-               cfs_cap_raise(CFS_CAP_SYS_RESOURCE);
+       old_cred = llog_raise_resource();
        rc = lop->lop_declare_create(env, loghandle, th);
-       if (!raised)
-               cfs_cap_lower(CFS_CAP_SYS_RESOURCE);
+       llog_restore_resource(old_cred);
        RETURN(rc);
 }
 
 int llog_create(const struct lu_env *env, struct llog_handle *handle,
                struct thandle *th)
 {
+       const struct cred *old_cred;
        struct llog_operations  *lop;
-       int                      raised, rc;
+       int rc;
 
        ENTRY;
 
@@ -736,12 +1028,9 @@ int llog_create(const struct lu_env *env, struct llog_handle *handle,
        if (lop->lop_create == NULL)
                RETURN(-EOPNOTSUPP);
 
-       raised = cfs_cap_raised(CFS_CAP_SYS_RESOURCE);
-       if (!raised)
-               cfs_cap_raise(CFS_CAP_SYS_RESOURCE);
+       old_cred = llog_raise_resource();
        rc = lop->lop_create(env, handle, th);
-       if (!raised)
-               cfs_cap_lower(CFS_CAP_SYS_RESOURCE);
+       llog_restore_resource(old_cred);
        RETURN(rc);
 }
 
@@ -750,8 +1039,9 @@ int llog_declare_write_rec(const struct lu_env *env,
                           struct llog_rec_hdr *rec, int idx,
                           struct thandle *th)
 {
+       const struct cred *old_cred;
        struct llog_operations  *lop;
-       int                      raised, rc;
+       int rc;
 
        ENTRY;
 
@@ -762,12 +1052,9 @@ int llog_declare_write_rec(const struct lu_env *env,
        if (lop->lop_declare_write_rec == NULL)
                RETURN(-EOPNOTSUPP);
 
-       raised = cfs_cap_raised(CFS_CAP_SYS_RESOURCE);
-       if (!raised)
-               cfs_cap_raise(CFS_CAP_SYS_RESOURCE);
+       old_cred = llog_raise_resource();
        rc = lop->lop_declare_write_rec(env, handle, rec, idx, th);
-       if (!raised)
-               cfs_cap_lower(CFS_CAP_SYS_RESOURCE);
+       llog_restore_resource(old_cred);
        RETURN(rc);
 }
 
@@ -775,28 +1062,44 @@ int llog_write_rec(const struct lu_env *env, struct llog_handle *handle,
                   struct llog_rec_hdr *rec, struct llog_cookie *logcookies,
                   int idx, struct thandle *th)
 {
+       const struct cred *old_cred;
        struct llog_operations  *lop;
-       int                      raised, rc, buflen;
+       int rc, buflen;
 
        ENTRY;
 
+       /* API sanity checks */
+       if (handle == NULL) {
+               CERROR("loghandle is missed\n");
+               RETURN(-EPROTO);
+       } else if (handle->lgh_obj == NULL) {
+               CERROR("loghandle %p with NULL object\n",
+                       handle);
+               RETURN(-EPROTO);
+       } else if (th == NULL) {
+               CERROR("%s: missed transaction handle\n",
+                       handle->lgh_obj->do_lu.lo_dev->ld_obd->obd_name);
+               RETURN(-EPROTO);
+       } else if (handle->lgh_hdr == NULL) {
+               CERROR("%s: loghandle %p with no header\n",
+                       handle->lgh_obj->do_lu.lo_dev->ld_obd->obd_name,
+                       handle);
+               RETURN(-EPROTO);
+       }
+
        rc = llog_handle2ops(handle, &lop);
        if (rc)
                RETURN(rc);
 
-       LASSERT(lop);
        if (lop->lop_write_rec == NULL)
                RETURN(-EOPNOTSUPP);
 
        buflen = rec->lrh_len;
        LASSERT(cfs_size_round(buflen) == buflen);
 
-       raised = cfs_cap_raised(CFS_CAP_SYS_RESOURCE);
-       if (!raised)
-               cfs_cap_raise(CFS_CAP_SYS_RESOURCE);
+       old_cred = llog_raise_resource();
        rc = lop->lop_write_rec(env, handle, rec, logcookies, idx, th);
-       if (!raised)
-               cfs_cap_lower(CFS_CAP_SYS_RESOURCE);
+       llog_restore_resource(old_cred);
        RETURN(rc);
 }
 
@@ -804,19 +1107,17 @@ int llog_add(const struct lu_env *env, struct llog_handle *lgh,
             struct llog_rec_hdr *rec, struct llog_cookie *logcookies,
             struct thandle *th)
 {
-       int raised, rc;
+       const struct cred *old_cred;
+       int rc;
 
        ENTRY;
 
        if (lgh->lgh_logops->lop_add == NULL)
                RETURN(-EOPNOTSUPP);
 
-       raised = cfs_cap_raised(CFS_CAP_SYS_RESOURCE);
-       if (!raised)
-               cfs_cap_raise(CFS_CAP_SYS_RESOURCE);
+       old_cred = llog_raise_resource();
        rc = lgh->lgh_logops->lop_add(env, lgh, rec, logcookies, th);
-       if (!raised)
-               cfs_cap_lower(CFS_CAP_SYS_RESOURCE);
+       llog_restore_resource(old_cred);
        RETURN(rc);
 }
 EXPORT_SYMBOL(llog_add);
@@ -824,19 +1125,17 @@ EXPORT_SYMBOL(llog_add);
 int llog_declare_add(const struct lu_env *env, struct llog_handle *lgh,
                     struct llog_rec_hdr *rec, struct thandle *th)
 {
-       int raised, rc;
+       const struct cred *old_cred;
+       int rc;
 
        ENTRY;
 
        if (lgh->lgh_logops->lop_declare_add == NULL)
                RETURN(-EOPNOTSUPP);
 
-       raised = cfs_cap_raised(CFS_CAP_SYS_RESOURCE);
-       if (!raised)
-               cfs_cap_raise(CFS_CAP_SYS_RESOURCE);
+       old_cred = llog_raise_resource();
        rc = lgh->lgh_logops->lop_declare_add(env, lgh, rec, th);
-       if (!raised)
-               cfs_cap_lower(CFS_CAP_SYS_RESOURCE);
+       llog_restore_resource(old_cred);
        RETURN(rc);
 }
 EXPORT_SYMBOL(llog_declare_add);
@@ -866,6 +1165,9 @@ int llog_open_create(const struct lu_env *env, struct llog_ctxt *ctxt,
 
        d = lu2dt_dev((*res)->lgh_obj->do_lu.lo_dev);
 
+       if (unlikely(unlikely(d->dd_rdonly)))
+               RETURN(-EROFS);
+
        th = dt_trans_create(env, d);
        if (IS_ERR(th))
                GOTO(out, rc = PTR_ERR(th));
@@ -933,7 +1235,8 @@ int llog_write(const struct lu_env *env, struct llog_handle *loghandle,
 {
        struct dt_device        *dt;
        struct thandle          *th;
-       int                      rc;
+       bool                    need_cookie;
+       int                     rc;
 
        ENTRY;
 
@@ -943,6 +1246,9 @@ int llog_write(const struct lu_env *env, struct llog_handle *loghandle,
 
        dt = lu2dt_dev(loghandle->lgh_obj->do_lu.lo_dev);
 
+       if (unlikely(unlikely(dt->dd_rdonly)))
+               RETURN(-EROFS);
+
        th = dt_trans_create(env, dt);
        if (IS_ERR(th))
                RETURN(PTR_ERR(th));
@@ -956,8 +1262,21 @@ int llog_write(const struct lu_env *env, struct llog_handle *loghandle,
        if (rc)
                GOTO(out_trans, rc);
 
+       need_cookie = !(idx == LLOG_HEADER_IDX || idx == LLOG_NEXT_IDX);
+
        down_write(&loghandle->lgh_lock);
-       rc = llog_write_rec(env, loghandle, rec, NULL, idx, th);
+       if (need_cookie) {
+               struct llog_thread_info *lti = llog_info(env);
+
+               /* cookie comes from llog_process_thread */
+               rc = llog_write_rec(env, loghandle, rec, &lti->lgi_cookie,
+                                   rec->lrh_index, th);
+               /* upper layer didn`t pass cookie so change rc */
+               rc = (rc == 1 ? 0 : rc);
+       } else {
+               rc = llog_write_rec(env, loghandle, rec, NULL, idx, th);
+       }
+
        up_write(&loghandle->lgh_lock);
 out_trans:
        dt_trans_stop(env, dt, th);
@@ -969,7 +1288,7 @@ int llog_open(const struct lu_env *env, struct llog_ctxt *ctxt,
              struct llog_handle **lgh, struct llog_logid *logid,
              char *name, enum llog_open_param open_param)
 {
-       int      raised;
+       const struct cred *old_cred;
        int      rc;
 
        ENTRY;
@@ -988,12 +1307,9 @@ int llog_open(const struct lu_env *env, struct llog_ctxt *ctxt,
        (*lgh)->lgh_ctxt = ctxt;
        (*lgh)->lgh_logops = ctxt->loc_logops;
 
-       raised = cfs_cap_raised(CFS_CAP_SYS_RESOURCE);
-       if (!raised)
-               cfs_cap_raise(CFS_CAP_SYS_RESOURCE);
+       old_cred = llog_raise_resource();
        rc = ctxt->loc_logops->lop_open(env, *lgh, logid, name, open_param);
-       if (!raised)
-               cfs_cap_lower(CFS_CAP_SYS_RESOURCE);
+       llog_restore_resource(old_cred);
        if (rc) {
                llog_free_handle(*lgh);
                *lgh = NULL;
@@ -1004,20 +1320,7 @@ EXPORT_SYMBOL(llog_open);
 
 int llog_close(const struct lu_env *env, struct llog_handle *loghandle)
 {
-       struct llog_operations  *lop;
-       int                      rc;
-
-       ENTRY;
-
-       rc = llog_handle2ops(loghandle, &lop);
-       if (rc)
-               GOTO(out, rc);
-       if (lop->lop_close == NULL)
-               GOTO(out, rc = -EOPNOTSUPP);
-       rc = lop->lop_close(env, loghandle);
-out:
-       llog_handle_put(loghandle);
-       RETURN(rc);
+       return llog_handle_put(env, loghandle);
 }
 EXPORT_SYMBOL(llog_close);
 
@@ -1132,3 +1435,22 @@ out_close:
        RETURN(rc);
 }
 EXPORT_SYMBOL(llog_backup);
+
+/* Get size of llog */
+__u64 llog_size(const struct lu_env *env, struct llog_handle *llh)
+{
+       int rc;
+       struct lu_attr la;
+
+       rc = llh->lgh_obj->do_ops->do_attr_get(env, llh->lgh_obj, &la);
+       if (rc) {
+               CERROR("%s: attr_get failed for "DFID": rc = %d\n",
+                      llh->lgh_ctxt->loc_obd->obd_name,
+                      PFID(&llh->lgh_id.lgl_oi.oi_fid), rc);
+               return 0;
+       }
+
+       return la.la_size;
+}
+EXPORT_SYMBOL(llog_size);
+