diff --git a/drivers/staging/lustre/include/uapi/linux/lustre/lustre_ioctl.h b/drivers/staging/lustre/include/uapi/linux/lustre/lustre_ioctl.h
index 6e4e109..098b6451 100644
--- a/drivers/staging/lustre/include/uapi/linux/lustre/lustre_ioctl.h
+++ b/drivers/staging/lustre/include/uapi/linux/lustre/lustre_ioctl.h
@@ -172,7 +172,7 @@ static inline __u32 obd_ioctl_packlen(struct obd_ioctl_data *data)
 #define OBD_GET_VERSION		_IOWR('f', 144, OBD_IOC_DATA_TYPE)
 /*	OBD_IOC_GSS_SUPPORT	_IOWR('f', 145, OBD_IOC_DATA_TYPE) */
 /*	OBD_IOC_CLOSE_UUID	_IOWR('f', 147, OBD_IOC_DATA_TYPE) */
-#define OBD_IOC_CHANGELOG_SEND	_IOW('f', 148, OBD_IOC_DATA_TYPE)
+/*	OBD_IOC_CHANGELOG_SEND	_IOW('f', 148, OBD_IOC_DATA_TYPE) */
 #define OBD_IOC_GETDEVICE	_IOWR('f', 149, OBD_IOC_DATA_TYPE)
 #define OBD_IOC_FID2PATH	_IOWR('f', 150, OBD_IOC_DATA_TYPE)
 /*	lustre/lustre_user.h	151-153 */
diff --git a/drivers/staging/lustre/include/uapi/linux/lustre/lustre_kernelcomm.h b/drivers/staging/lustre/include/uapi/linux/lustre/lustre_kernelcomm.h
index 94dadbe..d84a8fc 100644
--- a/drivers/staging/lustre/include/uapi/linux/lustre/lustre_kernelcomm.h
+++ b/drivers/staging/lustre/include/uapi/linux/lustre/lustre_kernelcomm.h
@@ -54,15 +54,12 @@ struct kuc_hdr {
 	__u16 kuc_msglen;
 } __aligned(sizeof(__u64));
 
-#define KUC_CHANGELOG_MSG_MAXSIZE (sizeof(struct kuc_hdr) + CR_MAXSIZE)
-
 #define KUC_MAGIC		0x191C /*Lustre9etLinC */
 
 /* kuc_msgtype values are defined in each transport */
 enum kuc_transport_type {
 	KUC_TRANSPORT_GENERIC	= 1,
 	KUC_TRANSPORT_HSM	= 2,
-	KUC_TRANSPORT_CHANGELOG	= 3,
 };
 
 enum kuc_generic_message_type {
diff --git a/drivers/staging/lustre/include/uapi/linux/lustre/lustre_user.h b/drivers/staging/lustre/include/uapi/linux/lustre/lustre_user.h
index b8525e5..715f1c5 100644
--- a/drivers/staging/lustre/include/uapi/linux/lustre/lustre_user.h
+++ b/drivers/staging/lustre/include/uapi/linux/lustre/lustre_user.h
@@ -967,13 +967,6 @@ static inline void changelog_remap_rec(struct changelog_rec *rec,
 	rec->cr_flags = (rec->cr_flags & CLF_FLAGMASK) | crf_wanted;
 }
 
-struct ioc_changelog {
-	__u64 icc_recno;
-	__u32 icc_mdtindex;
-	__u32 icc_id;
-	__u32 icc_flags;
-};
-
 enum changelog_message_type {
 	CL_RECORD = 10, /* message is a changelog_rec */
 	CL_EOF    = 11, /* at end of current changelog */
diff --git a/drivers/staging/lustre/lustre/include/obd.h b/drivers/staging/lustre/lustre/include/obd.h
index 11e7ae8..76ae0b3 100644
--- a/drivers/staging/lustre/lustre/include/obd.h
+++ b/drivers/staging/lustre/lustre/include/obd.h
@@ -345,6 +345,8 @@ struct client_obd {
 	void			*cl_lru_work;
 	/* hash tables for osc_quota_info */
 	struct rhashtable	cl_quota_hash[MAXQUOTAS];
+	/* Links to the global list of registered changelog devices */
+	struct list_head	cl_chg_dev_linkage;
 };
 
 #define obd2cli_tgt(obd) ((char *)(obd)->u.cli.cl_target_uuid.uuid)
diff --git a/drivers/staging/lustre/lustre/ldlm/ldlm_lib.c b/drivers/staging/lustre/lustre/ldlm/ldlm_lib.c
index 32eda4f..732ef3a 100644
--- a/drivers/staging/lustre/lustre/ldlm/ldlm_lib.c
+++ b/drivers/staging/lustre/lustre/ldlm/ldlm_lib.c
@@ -395,6 +395,8 @@ int client_obd_setup(struct obd_device *obddev, struct lustre_cfg *lcfg)
 	init_waitqueue_head(&cli->cl_mod_rpcs_waitq);
 	cli->cl_mod_tag_bitmap = NULL;
 
+	INIT_LIST_HEAD(&cli->cl_chg_dev_linkage);
+
 	if (connect_op == MDS_CONNECT) {
 		cli->cl_max_mod_rpcs_in_flight = cli->cl_max_rpcs_in_flight - 1;
 		cli->cl_mod_tag_bitmap = kcalloc(BITS_TO_LONGS(OBD_MAX_RIF_MAX),
diff --git a/drivers/staging/lustre/lustre/llite/dir.c b/drivers/staging/lustre/lustre/llite/dir.c
index 19c5e9c..36cea8d 100644
--- a/drivers/staging/lustre/lustre/llite/dir.c
+++ b/drivers/staging/lustre/lustre/llite/dir.c
@@ -1481,14 +1481,6 @@ static long ll_dir_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		return obd_iocontrol(cmd, sbi->ll_md_exp, 0, NULL,
 				     (void __user *)arg);
 	}
-	case OBD_IOC_CHANGELOG_SEND:
-	case OBD_IOC_CHANGELOG_CLEAR:
-		if (!capable(CAP_SYS_ADMIN))
-			return -EPERM;
-
-		rc = copy_and_ioctl(cmd, sbi->ll_md_exp, (void __user *)arg,
-				    sizeof(struct ioc_changelog));
-		return rc;
 	case OBD_IOC_FID2PATH:
 		return ll_fid2path(inode, (void __user *)arg);
 	case LL_IOC_GETPARENT:
diff --git a/drivers/staging/lustre/lustre/lmv/lmv_obd.c b/drivers/staging/lustre/lustre/lmv/lmv_obd.c
index 952c68e..32bb9fc 100644
--- a/drivers/staging/lustre/lustre/lmv/lmv_obd.c
+++ b/drivers/staging/lustre/lustre/lmv/lmv_obd.c
@@ -951,19 +951,6 @@ static int lmv_iocontrol(unsigned int cmd, struct obd_export *exp,
 		kfree(oqctl);
 		break;
 	}
-	case OBD_IOC_CHANGELOG_SEND:
-	case OBD_IOC_CHANGELOG_CLEAR: {
-		struct ioc_changelog *icc = karg;
-
-		if (icc->icc_mdtindex >= count)
-			return -ENODEV;
-
-		tgt = lmv->tgts[icc->icc_mdtindex];
-		if (!tgt || !tgt->ltd_exp || !tgt->ltd_active)
-			return -ENODEV;
-		rc = obd_iocontrol(cmd, tgt->ltd_exp, sizeof(*icc), icc, NULL);
-		break;
-	}
 	case LL_IOC_GET_CONNECT_FLAGS: {
 		tgt = lmv->tgts[0];
 
diff --git a/drivers/staging/lustre/lustre/mdc/Makefile b/drivers/staging/lustre/lustre/mdc/Makefile
index 64cf49e..5f48e91 100644
--- a/drivers/staging/lustre/lustre/mdc/Makefile
+++ b/drivers/staging/lustre/lustre/mdc/Makefile
@@ -2,4 +2,4 @@ ccflags-y += -I$(srctree)/drivers/staging/lustre/include
 ccflags-y += -I$(srctree)/drivers/staging/lustre/lustre/include
 
 obj-$(CONFIG_LUSTRE_FS) += mdc.o
-mdc-y := mdc_request.o mdc_reint.o mdc_lib.o mdc_locks.o lproc_mdc.o
+mdc-y := mdc_changelog.o mdc_request.o mdc_reint.o mdc_lib.o mdc_locks.o lproc_mdc.o
diff --git a/drivers/staging/lustre/lustre/mdc/mdc_changelog.c b/drivers/staging/lustre/lustre/mdc/mdc_changelog.c
new file mode 100644
index 0000000..a5f3c64
--- /dev/null
+++ b/drivers/staging/lustre/lustre/mdc/mdc_changelog.c
@@ -0,0 +1,722 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * GPL HEADER START
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 only,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License version 2 for more details (a copy is included
+ * in the LICENSE file that accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; If not, see
+ * http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * GPL HEADER END
+ */
+/*
+ * Copyright (c) 2017, Commissariat a l'Energie Atomique et aux Energies
+ *                     Alternatives.
+ *
+ * Author: Henri Doreau <henri.doreau@cea.fr>
+ */
+
+#define DEBUG_SUBSYSTEM S_MDC
+
+#include <linux/init.h>
+#include <linux/kthread.h>
+#include <linux/poll.h>
+#include <linux/miscdevice.h>
+
+#include <lustre_log.h>
+
+#include "mdc_internal.h"
+
+/*
+ * -- Changelog delivery through character device --
+ */
+
+/**
+ * Mutex to protect chlg_registered_devices below
+ */
+static DEFINE_MUTEX(chlg_registered_dev_lock);
+
+/**
+ * Global linked list of all registered devices (one per MDT).
+ */
+static LIST_HEAD(chlg_registered_devices);
+
+struct chlg_registered_dev {
+	/* Device name of the form "changelog-{MDTNAME}" */
+	char			ced_name[32];
+	/* Misc device descriptor */
+	struct miscdevice	ced_misc;
+	/* OBDs referencing this device (multiple mount point) */
+	struct list_head	ced_obds;
+	/* Reference counter for proper deregistration */
+	struct kref		ced_refs;
+	/* Link within the global chlg_registered_devices */
+	struct list_head	ced_link;
+};
+
+struct chlg_reader_state {
+	/* Shortcut to the corresponding OBD device */
+	struct obd_device	*crs_obd;
+	/* An error occurred that prevents from reading further */
+	bool			 crs_err;
+	/* EOF, no more records available */
+	bool			 crs_eof;
+	/* Userland reader closed connection */
+	bool			 crs_closed;
+	/* Desired start position */
+	u64			 crs_start_offset;
+	/* Wait queue for the catalog processing thread */
+	wait_queue_head_t	 crs_waitq_prod;
+	/* Wait queue for the record copy threads */
+	wait_queue_head_t	 crs_waitq_cons;
+	/* Mutex protecting crs_rec_count and crs_rec_queue */
+	struct mutex		 crs_lock;
+	/* Number of item in the list */
+	u64			 crs_rec_count;
+	/* List of prefetched enqueued_record::enq_linkage_items */
+	struct list_head	 crs_rec_queue;
+};
+
+struct chlg_rec_entry {
+	/* Link within the chlg_reader_state::crs_rec_queue list */
+	struct list_head	enq_linkage;
+	/* Data (enq_record) field length */
+	u64			enq_length;
+	/* Copy of a changelog record (see struct llog_changelog_rec) */
+	struct changelog_rec	enq_record[];
+};
+
+enum {
+	/* Number of records to prefetch locally. */
+	CDEV_CHLG_MAX_PREFETCH = 1024,
+};
+
+/**
+ * ChangeLog catalog processing callback invoked on each record.
+ * If the current record is eligible to userland delivery, push
+ * it into the crs_rec_queue where the consumer code will fetch it.
+ *
+ * @param[in]     env  (unused)
+ * @param[in]     llh  Client-side handle used to identify the llog
+ * @param[in]     hdr  Header of the current llog record
+ * @param[in,out] data chlg_reader_state passed from caller
+ *
+ * @return 0 or LLOG_PROC_* control code on success, negated error on failure.
+ */
+static int chlg_read_cat_process_cb(const struct lu_env *env,
+				    struct llog_handle *llh,
+				    struct llog_rec_hdr *hdr, void *data)
+{
+	struct llog_changelog_rec *rec;
+	struct chlg_reader_state *crs = data;
+	struct chlg_rec_entry *enq;
+	size_t len;
+	int rc;
+
+	LASSERT(crs);
+	LASSERT(hdr);
+
+	rec = container_of(hdr, struct llog_changelog_rec, cr_hdr);
+
+	if (rec->cr_hdr.lrh_type != CHANGELOG_REC) {
+		rc = -EINVAL;
+		CERROR("%s: not a changelog rec %x/%d in llog : rc = %d\n",
+		       crs->crs_obd->obd_name, rec->cr_hdr.lrh_type,
+		       rec->cr.cr_type, rc);
+		return rc;
+	}
+
+	/* Skip undesired records */
+	if (rec->cr.cr_index < crs->crs_start_offset)
+		return 0;
+
+	CDEBUG(D_HSM, "%llu %02d%-5s %llu 0x%x t=" DFID " p=" DFID " %.*s\n",
+	       rec->cr.cr_index, rec->cr.cr_type,
+	       changelog_type2str(rec->cr.cr_type), rec->cr.cr_time,
+	       rec->cr.cr_flags & CLF_FLAGMASK,
+	       PFID(&rec->cr.cr_tfid), PFID(&rec->cr.cr_pfid),
+	       rec->cr.cr_namelen, changelog_rec_name(&rec->cr));
+
+	wait_event_idle(crs->crs_waitq_prod,
+			(crs->crs_rec_count < CDEV_CHLG_MAX_PREFETCH ||
+			 crs->crs_closed));
+
+	if (crs->crs_closed)
+		return LLOG_PROC_BREAK;
+
+	len = changelog_rec_size(&rec->cr) + rec->cr.cr_namelen;
+	enq = kzalloc(sizeof(*enq) + len, GFP_KERNEL);
+	if (!enq)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&enq->enq_linkage);
+	enq->enq_length = len;
+	memcpy(enq->enq_record, &rec->cr, len);
+
+	mutex_lock(&crs->crs_lock);
+	list_add_tail(&enq->enq_linkage, &crs->crs_rec_queue);
+	crs->crs_rec_count++;
+	mutex_unlock(&crs->crs_lock);
+
+	wake_up_all(&crs->crs_waitq_cons);
+
+	return 0;
+}
+
+/**
+ * Remove record from the list it is attached to and free it.
+ */
+static void enq_record_delete(struct chlg_rec_entry *rec)
+{
+	list_del(&rec->enq_linkage);
+	kfree(rec);
+}
+
+/**
+ * Release resources associated to a changelog_reader_state instance.
+ *
+ * @param  crs  CRS instance to release.
+ */
+static void crs_free(struct chlg_reader_state *crs)
+{
+	struct chlg_rec_entry *rec;
+	struct chlg_rec_entry *tmp;
+
+	list_for_each_entry_safe(rec, tmp, &crs->crs_rec_queue, enq_linkage)
+		enq_record_delete(rec);
+
+	kfree(crs);
+}
+
+/**
+ * Record prefetch thread entry point. Opens the changelog catalog and starts
+ * reading records.
+ *
+ * @param[in,out]  args  chlg_reader_state passed from caller.
+ * @return 0 on success, negated error code on failure.
+ */
+static int chlg_load(void *args)
+{
+	struct chlg_reader_state *crs = args;
+	struct obd_device *obd = crs->crs_obd;
+	struct llog_ctxt *ctx = NULL;
+	struct llog_handle *llh = NULL;
+	int rc;
+
+	ctx = llog_get_context(obd, LLOG_CHANGELOG_REPL_CTXT);
+	if (!ctx) {
+		rc = -ENOENT;
+		goto err_out;
+	}
+
+	rc = llog_open(NULL, ctx, &llh, NULL, CHANGELOG_CATALOG,
+		       LLOG_OPEN_EXISTS);
+	if (rc) {
+		CERROR("%s: fail to open changelog catalog: rc = %d\n",
+		       obd->obd_name, rc);
+		goto err_out;
+	}
+
+	rc = llog_init_handle(NULL, llh, LLOG_F_IS_CAT | LLOG_F_EXT_JOBID,
+			      NULL);
+	if (rc) {
+		CERROR("%s: fail to init llog handle: rc = %d\n",
+		       obd->obd_name, rc);
+		goto err_out;
+	}
+
+	rc = llog_cat_process(NULL, llh, chlg_read_cat_process_cb, crs, 0, 0);
+	if (rc < 0) {
+		CERROR("%s: fail to process llog: rc = %d\n",
+		       obd->obd_name, rc);
+		goto err_out;
+	}
+
+err_out:
+	crs->crs_err = true;
+	wake_up_all(&crs->crs_waitq_cons);
+
+	if (llh)
+		llog_cat_close(NULL, llh);
+
+	if (ctx)
+		llog_ctxt_put(ctx);
+
+	wait_event_idle(crs->crs_waitq_prod, crs->crs_closed);
+	crs_free(crs);
+	return rc;
+}
+
+/**
+ * Read handler, dequeues records from the chlg_reader_state if any.
+ * No partial records are copied to userland so this function can return less
+ * data than required (short read).
+ *
+ * @param[in]   file   File pointer to the character device.
+ * @param[out]  buff   Userland buffer where to copy the records.
+ * @param[in]   count  Userland buffer size.
+ * @param[out]  ppos   File position, updated with the index number of the next
+ *		       record to read.
+ * @return number of copied bytes on success, negated error code on failure.
+ */
+static ssize_t chlg_read(struct file *file, char __user *buff, size_t count,
+			 loff_t *ppos)
+{
+	struct chlg_reader_state *crs = file->private_data;
+	struct chlg_rec_entry *rec;
+	struct chlg_rec_entry *tmp;
+	ssize_t  written_total = 0;
+	LIST_HEAD(consumed);
+
+	if (file->f_flags & O_NONBLOCK && crs->crs_rec_count == 0)
+		return -EAGAIN;
+
+	wait_event_idle(crs->crs_waitq_cons,
+			crs->crs_rec_count > 0 || crs->crs_eof || crs->crs_err);
+
+	mutex_lock(&crs->crs_lock);
+	list_for_each_entry_safe(rec, tmp, &crs->crs_rec_queue, enq_linkage) {
+		if (written_total + rec->enq_length > count)
+			break;
+
+		if (copy_to_user(buff, rec->enq_record, rec->enq_length)) {
+			if (written_total == 0)
+				written_total = -EFAULT;
+			break;
+		}
+
+		buff += rec->enq_length;
+		written_total += rec->enq_length;
+
+		crs->crs_rec_count--;
+		list_move_tail(&rec->enq_linkage, &consumed);
+
+		crs->crs_start_offset = rec->enq_record->cr_index + 1;
+	}
+	mutex_unlock(&crs->crs_lock);
+
+	if (written_total > 0)
+		wake_up_all(&crs->crs_waitq_prod);
+
+	list_for_each_entry_safe(rec, tmp, &consumed, enq_linkage)
+		enq_record_delete(rec);
+
+	*ppos = crs->crs_start_offset;
+
+	return written_total;
+}
+
+/**
+ * Jump to a given record index. Helper for chlg_llseek().
+ *
+ * @param[in,out]  crs     Internal reader state.
+ * @param[in]      offset  Desired offset (index record).
+ * @return 0 on success, negated error code on failure.
+ */
+static int chlg_set_start_offset(struct chlg_reader_state *crs, u64 offset)
+{
+	struct chlg_rec_entry *rec;
+	struct chlg_rec_entry *tmp;
+
+	mutex_lock(&crs->crs_lock);
+	if (offset < crs->crs_start_offset) {
+		mutex_unlock(&crs->crs_lock);
+		return -ERANGE;
+	}
+
+	crs->crs_start_offset = offset;
+	list_for_each_entry_safe(rec, tmp, &crs->crs_rec_queue, enq_linkage) {
+		struct changelog_rec *cr = rec->enq_record;
+
+		if (cr->cr_index >= crs->crs_start_offset)
+			break;
+
+		crs->crs_rec_count--;
+		enq_record_delete(rec);
+	}
+
+	mutex_unlock(&crs->crs_lock);
+	wake_up_all(&crs->crs_waitq_prod);
+	return 0;
+}
+
+/**
+ * Move read pointer to a certain record index, encoded as an offset.
+ *
+ * @param[in,out] file   File pointer to the changelog character device
+ * @param[in]	  off    Offset to skip, actually a record index, not byte count
+ * @param[in]	  whence Relative/Absolute interpretation of the offset
+ * @return the resulting position on success or negated error code on failure.
+ */
+static loff_t chlg_llseek(struct file *file, loff_t off, int whence)
+{
+	struct chlg_reader_state *crs = file->private_data;
+	loff_t pos;
+	int rc;
+
+	switch (whence) {
+	case SEEK_SET:
+		pos = off;
+		break;
+	case SEEK_CUR:
+		pos = file->f_pos + off;
+		break;
+	case SEEK_END:
+	default:
+		return -EINVAL;
+	}
+
+	/* We cannot go backward */
+	if (pos < file->f_pos)
+		return -EINVAL;
+
+	rc = chlg_set_start_offset(crs, pos);
+	if (rc != 0)
+		return rc;
+
+	file->f_pos = pos;
+	return pos;
+}
+
+/**
+ * Clear record range for a given changelog reader.
+ *
+ * @param[in]  crs     Current internal state.
+ * @param[in]  reader  Changelog reader ID (cl1, cl2...)
+ * @param[in]  record  Record index up which to clear
+ * @return 0 on success, negated error code on failure.
+ */
+static int chlg_clear(struct chlg_reader_state *crs, u32 reader, u64 record)
+{
+	struct obd_device *obd = crs->crs_obd;
+	struct changelog_setinfo cs  = {
+		.cs_recno = record,
+		.cs_id    = reader
+	};
+
+	return obd_set_info_async(NULL, obd->obd_self_export,
+				  strlen(KEY_CHANGELOG_CLEAR),
+				  KEY_CHANGELOG_CLEAR, sizeof(cs), &cs, NULL);
+}
+
+/** Maximum changelog control command size */
+#define CHLG_CONTROL_CMD_MAX	64
+
+/**
+ * Handle writes() into the changelog character device. Write() can be used
+ * to request special control operations.
+ *
+ * @param[in]  file  File pointer to the changelog character device
+ * @param[in]  buff  User supplied data (written data)
+ * @param[in]  count Number of written bytes
+ * @param[in]  off   (unused)
+ * @return number of written bytes on success, negated error code on failure.
+ */
+static ssize_t chlg_write(struct file *file, const char __user *buff,
+			  size_t count, loff_t *off)
+{
+	struct chlg_reader_state *crs = file->private_data;
+	char *kbuf;
+	u64 record;
+	u32 reader;
+	int rc = 0;
+
+	if (count > CHLG_CONTROL_CMD_MAX)
+		return -EINVAL;
+
+	kbuf = kzalloc(CHLG_CONTROL_CMD_MAX, GFP_KERNEL);
+	if (!kbuf)
+		return -ENOMEM;
+
+	if (copy_from_user(kbuf, buff, count)) {
+		rc = -EFAULT;
+		goto out_kbuf;
+	}
+
+	kbuf[CHLG_CONTROL_CMD_MAX - 1] = '\0';
+
+	if (sscanf(kbuf, "clear:cl%u:%llu", &reader, &record) == 2)
+		rc = chlg_clear(crs, reader, record);
+	else
+		rc = -EINVAL;
+
+out_kbuf:
+	kfree(kbuf);
+	return rc < 0 ? rc : count;
+}
+
+/**
+ * Find the OBD device associated to a changelog character device.
+ * @param[in]  cdev  character device instance descriptor
+ * @return corresponding OBD device or NULL if none was found.
+ */
+static struct obd_device *chlg_obd_get(dev_t cdev)
+{
+	int minor = MINOR(cdev);
+	struct obd_device *obd = NULL;
+	struct chlg_registered_dev *curr;
+
+	mutex_lock(&chlg_registered_dev_lock);
+	list_for_each_entry(curr, &chlg_registered_devices, ced_link) {
+		if (curr->ced_misc.minor == minor) {
+			/* take the first available OBD device attached */
+			obd = list_first_entry(&curr->ced_obds,
+					       struct obd_device,
+					       u.cli.cl_chg_dev_linkage);
+			break;
+		}
+	}
+	mutex_unlock(&chlg_registered_dev_lock);
+	return obd;
+}
+
+/**
+ * Open handler, initialize internal CRS state and spawn prefetch thread if
+ * needed.
+ * @param[in]  inode  Inode struct for the open character device.
+ * @param[in]  file   Corresponding file pointer.
+ * @return 0 on success, negated error code on failure.
+ */
+static int chlg_open(struct inode *inode, struct file *file)
+{
+	struct chlg_reader_state *crs;
+	struct obd_device *obd = chlg_obd_get(inode->i_rdev);
+	struct task_struct *task;
+	int rc;
+
+	if (!obd)
+		return -ENODEV;
+
+	crs = kzalloc(sizeof(*crs), GFP_KERNEL);
+	if (!crs)
+		return -ENOMEM;
+
+	crs->crs_obd = obd;
+	crs->crs_err = false;
+	crs->crs_eof = false;
+	crs->crs_closed = false;
+
+	mutex_init(&crs->crs_lock);
+	INIT_LIST_HEAD(&crs->crs_rec_queue);
+	init_waitqueue_head(&crs->crs_waitq_prod);
+	init_waitqueue_head(&crs->crs_waitq_cons);
+
+	if (file->f_mode & FMODE_READ) {
+		task = kthread_run(chlg_load, crs, "chlg_load_thread");
+		if (IS_ERR(task)) {
+			rc = PTR_ERR(task);
+			CERROR("%s: cannot start changelog thread: rc = %d\n",
+			       obd->obd_name, rc);
+			goto err_crs;
+		}
+	}
+
+	file->private_data = crs;
+	return 0;
+
+err_crs:
+	kfree(crs);
+	return rc;
+}
+
+/**
+ * Close handler, release resources.
+ *
+ * @param[in]  inode  Inode struct for the open character device.
+ * @param[in]  file   Corresponding file pointer.
+ * @return 0 on success, negated error code on failure.
+ */
+static int chlg_release(struct inode *inode, struct file *file)
+{
+	struct chlg_reader_state *crs = file->private_data;
+
+	if (file->f_mode & FMODE_READ) {
+		crs->crs_closed = true;
+		wake_up_all(&crs->crs_waitq_prod);
+	} else {
+		/* No producer thread, release resource ourselves */
+		crs_free(crs);
+	}
+	return 0;
+}
+
+/**
+ * Poll handler, indicates whether the device is readable (new records) and
+ * writable (always).
+ *
+ * @param[in]  file   Device file pointer.
+ * @param[in]  wait   (opaque)
+ * @return combination of the poll status flags.
+ */
+static unsigned int chlg_poll(struct file *file, poll_table *wait)
+{
+	struct chlg_reader_state *crs  = file->private_data;
+	unsigned int mask = 0;
+
+	mutex_lock(&crs->crs_lock);
+	poll_wait(file, &crs->crs_waitq_cons, wait);
+	if (crs->crs_rec_count > 0)
+		mask |= POLLIN | POLLRDNORM;
+	if (crs->crs_err)
+		mask |= POLLERR;
+	if (crs->crs_eof)
+		mask |= POLLHUP;
+	mutex_unlock(&crs->crs_lock);
+	return mask;
+}
+
+static const struct file_operations chlg_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= chlg_llseek,
+	.read		= chlg_read,
+	.write		= chlg_write,
+	.open		= chlg_open,
+	.release	= chlg_release,
+	.poll		= chlg_poll,
+};
+
+/**
+ * This uses obd_name of the form: "testfs-MDT0000-mdc-ffff88006501600"
+ * and returns a name of the form: "changelog-testfs-MDT0000".
+ */
+static void get_chlg_name(char *name, size_t name_len, struct obd_device *obd)
+{
+	int i;
+
+	snprintf(name, name_len, "changelog-%s", obd->obd_name);
+
+	/* Find the 2nd '-' from the end and truncate on it */
+	for (i = 0; i < 2; i++) {
+		char *p = strrchr(name, '-');
+
+		if (!p)
+			return;
+		*p = '\0';
+	}
+}
+
+/**
+ * Find a changelog character device by name.
+ * All devices registered during MDC setup are listed in a global list with
+ * their names attached.
+ */
+static struct chlg_registered_dev *
+chlg_registered_dev_find_by_name(const char *name)
+{
+	struct chlg_registered_dev *dit;
+
+	list_for_each_entry(dit, &chlg_registered_devices, ced_link)
+		if (strcmp(name, dit->ced_name) == 0)
+			return dit;
+	return NULL;
+}
+
+/**
+ * Find chlg_registered_dev structure for a given OBD device.
+ * This is bad O(n^2) but for each filesystem:
+ *   - N is # of MDTs times # of mount points
+ *   - this only runs at shutdown
+ */
+static struct chlg_registered_dev *
+chlg_registered_dev_find_by_obd(const struct obd_device *obd)
+{
+	struct chlg_registered_dev *dit;
+	struct obd_device *oit;
+
+	list_for_each_entry(dit, &chlg_registered_devices, ced_link)
+		list_for_each_entry(oit, &dit->ced_obds,
+				    u.cli.cl_chg_dev_linkage)
+			if (oit == obd)
+				return dit;
+	return NULL;
+}
+
+/**
+ * Changelog character device initialization.
+ * Register a misc character device with a dynamic minor number, under a name
+ * of the form: 'changelog-fsname-MDTxxxx'. Reference this OBD device with it.
+ *
+ * @param[in] obd  This MDC obd_device.
+ * @return 0 on success, negated error code on failure.
+ */
+int mdc_changelog_cdev_init(struct obd_device *obd)
+{
+	struct chlg_registered_dev *exist;
+	struct chlg_registered_dev *entry;
+	int rc;
+
+	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+	if (!entry)
+		return -ENOMEM;
+
+	get_chlg_name(entry->ced_name, sizeof(entry->ced_name), obd);
+
+	entry->ced_misc.minor = MISC_DYNAMIC_MINOR;
+	entry->ced_misc.name  = entry->ced_name;
+	entry->ced_misc.fops  = &chlg_fops;
+
+	kref_init(&entry->ced_refs);
+	INIT_LIST_HEAD(&entry->ced_obds);
+	INIT_LIST_HEAD(&entry->ced_link);
+
+	mutex_lock(&chlg_registered_dev_lock);
+	exist = chlg_registered_dev_find_by_name(entry->ced_name);
+	if (exist) {
+		kref_get(&exist->ced_refs);
+		list_add_tail(&obd->u.cli.cl_chg_dev_linkage, &exist->ced_obds);
+		rc = 0;
+		goto out_unlock;
+	}
+
+	/* Register new character device */
+	rc = misc_register(&entry->ced_misc);
+	if (rc != 0)
+		goto out_unlock;
+
+	list_add_tail(&obd->u.cli.cl_chg_dev_linkage, &entry->ced_obds);
+	list_add_tail(&entry->ced_link, &chlg_registered_devices);
+
+	entry = NULL;	/* prevent it from being freed below */
+
+out_unlock:
+	mutex_unlock(&chlg_registered_dev_lock);
+	kfree(entry);
+	return rc;
+}
+
+/**
+ * Deregister a changelog character device whose refcount has reached zero.
+ */
+static void chlg_dev_clear(struct kref *kref)
+{
+	struct chlg_registered_dev *entry = container_of(kref,
+							 struct chlg_registered_dev,
+							 ced_refs);
+	list_del(&entry->ced_link);
+	misc_deregister(&entry->ced_misc);
+	kfree(entry);
+}
+
+/**
+ * Release OBD, decrease reference count of the corresponding changelog device.
+ */
+void mdc_changelog_cdev_finish(struct obd_device *obd)
+{
+	struct chlg_registered_dev *dev = chlg_registered_dev_find_by_obd(obd);
+
+	mutex_lock(&chlg_registered_dev_lock);
+	list_del_init(&obd->u.cli.cl_chg_dev_linkage);
+	kref_put(&dev->ced_refs, chlg_dev_clear);
+	mutex_unlock(&chlg_registered_dev_lock);
+}
diff --git a/drivers/staging/lustre/lustre/mdc/mdc_internal.h b/drivers/staging/lustre/lustre/mdc/mdc_internal.h
index 941a896..6da9046 100644
--- a/drivers/staging/lustre/lustre/mdc/mdc_internal.h
+++ b/drivers/staging/lustre/lustre/mdc/mdc_internal.h
@@ -129,6 +129,10 @@ enum ldlm_mode mdc_lock_match(struct obd_export *exp, __u64 flags,
 			      enum ldlm_mode mode,
 			      struct lustre_handle *lockh);
 
+int mdc_changelog_cdev_init(struct obd_device *obd);
+
+void mdc_changelog_cdev_finish(struct obd_device *obd);
+
 static inline int mdc_prep_elc_req(struct obd_export *exp,
 				   struct ptlrpc_request *req, int opc,
 				   struct list_head *cancels, int count)
diff --git a/drivers/staging/lustre/lustre/mdc/mdc_request.c b/drivers/staging/lustre/lustre/mdc/mdc_request.c
index 8f8e3d2..3692b1c 100644
--- a/drivers/staging/lustre/lustre/mdc/mdc_request.c
+++ b/drivers/staging/lustre/lustre/mdc/mdc_request.c
@@ -35,7 +35,6 @@
 
 # include <linux/module.h>
 # include <linux/pagemap.h>
-# include <linux/miscdevice.h>
 # include <linux/init.h>
 # include <linux/utsname.h>
 # include <linux/file.h>
@@ -1810,174 +1809,6 @@ static int mdc_ioc_hsm_request(struct obd_export *exp,
 	return rc;
 }
 
-static struct kuc_hdr *changelog_kuc_hdr(char *buf, size_t len, u32 flags)
-{
-	struct kuc_hdr *lh = (struct kuc_hdr *)buf;
-
-	LASSERT(len <= KUC_CHANGELOG_MSG_MAXSIZE);
-
-	lh->kuc_magic = KUC_MAGIC;
-	lh->kuc_transport = KUC_TRANSPORT_CHANGELOG;
-	lh->kuc_flags = flags;
-	lh->kuc_msgtype = CL_RECORD;
-	lh->kuc_msglen = len;
-	return lh;
-}
-
-struct changelog_show {
-	__u64		cs_startrec;
-	enum changelog_send_flag	cs_flags;
-	struct file	*cs_fp;
-	char		*cs_buf;
-	struct obd_device *cs_obd;
-};
-
-static inline char *cs_obd_name(struct changelog_show *cs)
-{
-	return cs->cs_obd->obd_name;
-}
-
-static int changelog_kkuc_cb(const struct lu_env *env, struct llog_handle *llh,
-			     struct llog_rec_hdr *hdr, void *data)
-{
-	struct changelog_show *cs = data;
-	struct llog_changelog_rec *rec = (struct llog_changelog_rec *)hdr;
-	struct kuc_hdr *lh;
-	size_t len;
-	int rc;
-
-	if (rec->cr_hdr.lrh_type != CHANGELOG_REC) {
-		rc = -EINVAL;
-		CERROR("%s: not a changelog rec %x/%d: rc = %d\n",
-		       cs_obd_name(cs), rec->cr_hdr.lrh_type,
-		       rec->cr.cr_type, rc);
-		return rc;
-	}
-
-	if (rec->cr.cr_index < cs->cs_startrec) {
-		/* Skip entries earlier than what we are interested in */
-		CDEBUG(D_HSM, "rec=%llu start=%llu\n",
-		       rec->cr.cr_index, cs->cs_startrec);
-		return 0;
-	}
-
-	CDEBUG(D_HSM, "%llu %02d%-5s %llu 0x%x t=" DFID " p=" DFID
-		" %.*s\n", rec->cr.cr_index, rec->cr.cr_type,
-		changelog_type2str(rec->cr.cr_type), rec->cr.cr_time,
-		rec->cr.cr_flags & CLF_FLAGMASK,
-		PFID(&rec->cr.cr_tfid), PFID(&rec->cr.cr_pfid),
-		rec->cr.cr_namelen, changelog_rec_name(&rec->cr));
-
-	len = sizeof(*lh) + changelog_rec_size(&rec->cr) + rec->cr.cr_namelen;
-
-	/* Set up the message */
-	lh = changelog_kuc_hdr(cs->cs_buf, len, cs->cs_flags);
-	memcpy(lh + 1, &rec->cr, len - sizeof(*lh));
-
-	rc = libcfs_kkuc_msg_put(cs->cs_fp, lh);
-	CDEBUG(D_HSM, "kucmsg fp %p len %zu rc %d\n", cs->cs_fp, len, rc);
-
-	return rc;
-}
-
-static int mdc_changelog_send_thread(void *csdata)
-{
-	enum llog_flag flags = LLOG_F_IS_CAT;
-	struct changelog_show *cs = csdata;
-	struct llog_ctxt *ctxt = NULL;
-	struct llog_handle *llh = NULL;
-	struct kuc_hdr *kuch;
-	int rc;
-
-	CDEBUG(D_HSM, "changelog to fp=%p start %llu\n",
-	       cs->cs_fp, cs->cs_startrec);
-
-	cs->cs_buf = kzalloc(KUC_CHANGELOG_MSG_MAXSIZE, GFP_NOFS);
-	if (!cs->cs_buf) {
-		rc = -ENOMEM;
-		goto out;
-	}
-
-	/* Set up the remote catalog handle */
-	ctxt = llog_get_context(cs->cs_obd, LLOG_CHANGELOG_REPL_CTXT);
-	if (!ctxt) {
-		rc = -ENOENT;
-		goto out;
-	}
-	rc = llog_open(NULL, ctxt, &llh, NULL, CHANGELOG_CATALOG,
-		       LLOG_OPEN_EXISTS);
-	if (rc) {
-		CERROR("%s: fail to open changelog catalog: rc = %d\n",
-		       cs_obd_name(cs), rc);
-		goto out;
-	}
-
-	if (cs->cs_flags & CHANGELOG_FLAG_JOBID)
-		flags |= LLOG_F_EXT_JOBID;
-
-	rc = llog_init_handle(NULL, llh, flags, NULL);
-	if (rc) {
-		CERROR("llog_init_handle failed %d\n", rc);
-		goto out;
-	}
-
-	rc = llog_cat_process(NULL, llh, changelog_kkuc_cb, cs, 0, 0);
-
-	/* Send EOF no matter what our result */
-	kuch = changelog_kuc_hdr(cs->cs_buf, sizeof(*kuch), cs->cs_flags);
-	kuch->kuc_msgtype = CL_EOF;
-	libcfs_kkuc_msg_put(cs->cs_fp, kuch);
-
-out:
-	fput(cs->cs_fp);
-	if (llh)
-		llog_cat_close(NULL, llh);
-	if (ctxt)
-		llog_ctxt_put(ctxt);
-	kfree(cs->cs_buf);
-	kfree(cs);
-	return rc;
-}
-
-static int mdc_ioc_changelog_send(struct obd_device *obd,
-				  struct ioc_changelog *icc)
-{
-	struct changelog_show *cs;
-	struct task_struct *task;
-	int rc;
-
-	/* Freed in mdc_changelog_send_thread */
-	cs = kzalloc(sizeof(*cs), GFP_NOFS);
-	if (!cs)
-		return -ENOMEM;
-
-	cs->cs_obd = obd;
-	cs->cs_startrec = icc->icc_recno;
-	/* matching fput in mdc_changelog_send_thread */
-	cs->cs_fp = fget(icc->icc_id);
-	cs->cs_flags = icc->icc_flags;
-
-	/*
-	 * New thread because we should return to user app before
-	 * writing into our pipe
-	 */
-	task = kthread_run(mdc_changelog_send_thread, cs,
-			   "mdc_clg_send_thread");
-	if (IS_ERR(task)) {
-		rc = PTR_ERR(task);
-		CERROR("%s: can't start changelog thread: rc = %d\n",
-		       cs_obd_name(cs), rc);
-		kfree(cs);
-	} else {
-		rc = 0;
-		CDEBUG(D_HSM, "%s: started changelog thread\n",
-		       cs_obd_name(cs));
-	}
-
-	CERROR("Failed to start changelog thread: %d\n", rc);
-	return rc;
-}
-
 static int mdc_ioc_hsm_ct_start(struct obd_export *exp,
 				struct lustre_kernelcomm *lk);
 
@@ -2087,21 +1918,6 @@ static int mdc_iocontrol(unsigned int cmd, struct obd_export *exp, int len,
 		return -EINVAL;
 	}
 	switch (cmd) {
-	case OBD_IOC_CHANGELOG_SEND:
-		rc = mdc_ioc_changelog_send(obd, karg);
-		goto out;
-	case OBD_IOC_CHANGELOG_CLEAR: {
-		struct ioc_changelog *icc = karg;
-		struct changelog_setinfo cs = {
-			.cs_recno = icc->icc_recno,
-			.cs_id = icc->icc_id
-		};
-
-		rc = obd_set_info_async(NULL, exp, strlen(KEY_CHANGELOG_CLEAR),
-					KEY_CHANGELOG_CLEAR, sizeof(cs), &cs,
-					NULL);
-		goto out;
-	}
 	case OBD_IOC_FID2PATH:
 		rc = mdc_ioc_fid2path(exp, karg);
 		goto out;
@@ -2670,12 +2486,22 @@ static int mdc_setup(struct obd_device *obd, struct lustre_cfg *cfg)
 
 	rc = mdc_llog_init(obd);
 	if (rc) {
-		CERROR("failed to setup llogging subsystems\n");
+		CERROR("%s: failed to setup llogging subsystems: rc = %d\n",
+		       obd->obd_name, rc);
 		goto err_llog_cleanup;
 	}
 
+	rc = mdc_changelog_cdev_init(obd);
+	if (rc) {
+		CERROR("%s: failed to setup changelog char device: rc = %d\n",
+		       obd->obd_name, rc);
+		goto err_changelog_cleanup;
+	}
+
 	return 0;
 
+err_changelog_cleanup:
+	mdc_llog_finish(obd);
 err_llog_cleanup:
 	ldebugfs_free_md_stats(obd);
 	ptlrpc_lprocfs_unregister_obd(obd);
@@ -2714,6 +2540,8 @@ static int mdc_precleanup(struct obd_device *obd)
 	if (obd->obd_type->typ_refcnt <= 1)
 		libcfs_kkuc_group_rem(0, KUC_GRP_HSM);
 
+	mdc_changelog_cdev_finish(obd);
+
 	obd_cleanup_client_import(obd);
 	ptlrpc_lprocfs_unregister_obd(obd);
 	lprocfs_obd_cleanup(obd);
