protocol/client: cluster/afr: Support lock recovery and self heal.

Signed-off-by: Pavan Vilas Sondur <pavan@gluster.com>
Signed-off-by: Vijay Bellur <vijay@dev.gluster.com>

BUG: 865 (Add locks recovery support in GlusterFS)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=865

1 files changed, 949 insertions, 0 deletions

diff --git a/xlators/protocol/client/src/client-lk.c b/xlators/protocol/client/src/client-lk.c
new file mode 100644
index 00000000000..4ad7fc2b1ec
--- /dev/null
+++ b/xlators/protocol/client/src/client-lk.c
@@ -0,0 +1,949 @@
+/*
+  Copyright (c) 2008-2009 Gluster, Inc. <http://www.gluster.com>
+  This file is part of GlusterFS.
+
+  GlusterFS is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published
+  by the Free Software Foundation; either version 3 of the License,
+  or (at your option) any later version.
+
+  GlusterFS 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 for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see
+  <http://www.gnu.org/licenses/>.
+*/
+
+#include "common-utils.h"
+#include "xlator.h"
+#include "client.h"
+
+static void
+__insert_and_merge (clnt_fd_ctx_t *fdctx, client_posix_lock_t *lock);
+
+static int
+client_send_recovery_lock (call_frame_t *frame, xlator_t *this,
+                           client_posix_lock_t *lock);
+static void
+__dump_client_lock (client_posix_lock_t *lock)
+{
+        xlator_t *this = NULL;
+
+        this = THIS;
+
+        gf_log (this->name, GF_LOG_TRACE,
+                "{fd=%lld}"
+                "{%s lk-owner:%"PRIu64" %"PRId64" - %"PRId64"}"
+                "{start=%"PRId64" end=%"PRId64"}",
+                (unsigned long long)lock->fd,
+                lock->fl_type == F_WRLCK ? "Write-Lock" : "Read-Lock",
+                lock->owner,
+                lock->user_flock.l_start,
+                lock->user_flock.l_len,
+                lock->fl_start,
+                lock->fl_end);
+}
+
+static int
+dump_client_locks_fd (clnt_fd_ctx_t *fdctx)
+{
+        client_posix_lock_t *lock = NULL;
+        int count = 0;
+
+        pthread_mutex_lock (&fdctx->mutex);
+        {
+                list_for_each_entry (lock, &fdctx->lock_list, list) {
+                        __dump_client_lock (lock);
+                        count++;
+                }
+        }
+        pthread_mutex_unlock (&fdctx->mutex);
+
+        return count;
+
+}
+
+int
+dump_client_locks (inode_t *inode)
+{
+        fd_t             *fd    = NULL;
+        clnt_conf_t    *conf  = NULL;
+        xlator_t         *this  = NULL;
+        clnt_fd_ctx_t  *fdctx = NULL;
+
+        int total_count = 0;
+        int locks_fd_count   = 0;
+
+        this = THIS;
+        conf = this->private;
+
+        LOCK (&inode->lock);
+        {
+                list_for_each_entry (fd, &inode->fd_list, inode_list) {
+                        locks_fd_count = 0;
+
+                        pthread_mutex_lock (&conf->lock);
+                        {
+                                fdctx = this_fd_get_ctx (fd, this);
+                        }
+                        pthread_mutex_unlock (&conf->lock);
+
+                        if (fdctx)
+                                locks_fd_count = dump_client_locks_fd (fdctx);
+
+                        total_count += locks_fd_count;
+                }
+
+        }
+        UNLOCK (&inode->lock);
+
+        return total_count;
+
+}
+
+static off_t
+__get_lock_length (off_t start, off_t end)
+{
+        if (end == LLONG_MAX)
+                return 0;
+        else
+                return (end - start + 1);
+}
+
+/* Add two locks */
+static client_posix_lock_t *
+add_locks (client_posix_lock_t *l1, client_posix_lock_t *l2)
+{
+	client_posix_lock_t *sum = NULL;
+
+	sum = GF_CALLOC (1, sizeof (*sum), gf_client_mt_clnt_lock_t);
+	if (!sum)
+		return NULL;
+
+	sum->fl_start = min (l1->fl_start, l2->fl_start);
+	sum->fl_end   = max (l1->fl_end, l2->fl_end);
+
+        sum->user_flock.l_start = sum->fl_start;
+        sum->user_flock.l_len   = __get_lock_length (sum->fl_start,
+                                                     sum->fl_end);
+
+	return sum;
+}
+
+/* Return true if the locks have the same owner */
+static int
+same_owner (client_posix_lock_t *l1, client_posix_lock_t *l2)
+{
+        return ((l1->owner == l2->owner));
+}
+
+/* Return true if the locks overlap, false otherwise */
+static int
+locks_overlap (client_posix_lock_t *l1, client_posix_lock_t *l2)
+{
+	/*
+	   Note:
+	   FUSE always gives us absolute offsets, so no need to worry
+	   about SEEK_CUR or SEEK_END
+	*/
+
+	return ((l1->fl_end >= l2->fl_start) &&
+		(l2->fl_end >= l1->fl_start));
+}
+
+static void
+__delete_client_lock (client_posix_lock_t *lock)
+{
+	list_del_init (&lock->list);
+}
+
+/* Destroy a posix_lock */
+static void
+__destroy_client_lock (client_posix_lock_t *lock)
+{
+	free (lock);
+}
+
+/* Subtract two locks */
+struct _values {
+	client_posix_lock_t *locks[3];
+};
+
+/* {big} must always be contained inside {small} */
+static struct _values
+subtract_locks (client_posix_lock_t *big, client_posix_lock_t *small)
+{
+	struct _values v = { .locks = {0, 0, 0} };
+
+	if ((big->fl_start == small->fl_start) &&
+	    (big->fl_end   == small->fl_end)) {
+		/* both edges coincide with big */
+		v.locks[0] = GF_CALLOC (1, sizeof (client_posix_lock_t),
+                                        gf_client_mt_clnt_lock_t );
+		GF_ASSERT (v.locks[0]);
+		memcpy (v.locks[0], big, sizeof (client_posix_lock_t));
+		v.locks[0]->fl_type = small->fl_type;
+	}
+	else if ((small->fl_start > big->fl_start) &&
+		 (small->fl_end   < big->fl_end)) {
+		/* both edges lie inside big */
+		v.locks[0] = GF_CALLOC (1, sizeof (client_posix_lock_t),
+                                        gf_client_mt_clnt_lock_t);
+		GF_ASSERT (v.locks[0]);
+		v.locks[1] = GF_CALLOC (1, sizeof (client_posix_lock_t),
+                                     gf_client_mt_clnt_lock_t);
+		GF_ASSERT (v.locks[1]);
+		v.locks[2] = GF_CALLOC (1, sizeof (client_posix_lock_t),
+                                        gf_client_mt_clnt_lock_t);
+		GF_ASSERT (v.locks[2]);
+
+		memcpy (v.locks[0], big, sizeof (client_posix_lock_t));
+		v.locks[0]->fl_end = small->fl_start - 1;
+                v.locks[0]->user_flock.l_len = __get_lock_length (v.locks[0]->fl_start,
+                                                                  v.locks[0]->fl_end);
+
+		memcpy (v.locks[1], small, sizeof (client_posix_lock_t));
+		memcpy (v.locks[2], big, sizeof (client_posix_lock_t));
+		v.locks[2]->fl_start = small->fl_end + 1;
+                v.locks[2]->user_flock.l_start = small->fl_end + 1;
+	}
+	/* one edge coincides with big */
+	else if (small->fl_start == big->fl_start) {
+		v.locks[0] = GF_CALLOC (1, sizeof (client_posix_lock_t),
+                                        gf_client_mt_clnt_lock_t);
+		GF_ASSERT (v.locks[0]);
+		v.locks[1] = GF_CALLOC (1, sizeof (client_posix_lock_t),
+                                        gf_client_mt_clnt_lock_t);
+		GF_ASSERT (v.locks[1]);
+
+		memcpy (v.locks[0], big, sizeof (client_posix_lock_t));
+		v.locks[0]->fl_start = small->fl_end + 1;
+                v.locks[0]->user_flock.l_start = small->fl_end + 1;
+
+		memcpy (v.locks[1], small, sizeof (client_posix_lock_t));
+	}
+	else if (small->fl_end   == big->fl_end) {
+		v.locks[0] = GF_CALLOC (1, sizeof (client_posix_lock_t),
+                                        gf_client_mt_clnt_lock_t);
+		GF_ASSERT (v.locks[0]);
+		v.locks[1] = GF_CALLOC (1, sizeof (client_posix_lock_t),
+                                        gf_client_mt_clnt_lock_t);
+		GF_ASSERT (v.locks[1]);
+
+		memcpy (v.locks[0], big, sizeof (client_posix_lock_t));
+		v.locks[0]->fl_end = small->fl_start - 1;
+                v.locks[0]->user_flock.l_len = __get_lock_length (v.locks[0]->fl_start,
+                                                                  v.locks[0]->fl_end);
+
+		memcpy (v.locks[1], small, sizeof (client_posix_lock_t));
+	}
+        else {
+                gf_log ("client-protocol", GF_LOG_ERROR,
+                        "Unexpected case in subtract_locks. Please send "
+                        "a bug report to gluster-devel@nongnu.org");
+        }
+
+        return v;
+}
+
+static void
+__delete_unlck_locks (clnt_fd_ctx_t *fdctx)
+{
+	client_posix_lock_t *l = NULL;
+	client_posix_lock_t *tmp = NULL;
+
+	list_for_each_entry_safe (l, tmp, &fdctx->lock_list, list) {
+		if (l->fl_type == F_UNLCK) {
+			__delete_client_lock (l);
+			__destroy_client_lock (l);
+		}
+	}
+}
+
+static void
+__insert_lock (clnt_fd_ctx_t *fdctx, client_posix_lock_t *lock)
+{
+	list_add_tail (&lock->list, &fdctx->lock_list);
+
+	return;
+}
+
+static void
+__insert_and_merge (clnt_fd_ctx_t *fdctx, client_posix_lock_t *lock)
+{
+        client_posix_lock_t  *conf = NULL;
+        client_posix_lock_t  *t = NULL;
+        client_posix_lock_t  *sum = NULL;
+        int            i = 0;
+        struct _values v = { .locks = {0, 0, 0} };
+
+        list_for_each_entry_safe (conf, t, &fdctx->lock_list, list) {
+                if (!locks_overlap (conf, lock))
+                        continue;
+
+                if (same_owner (conf, lock)) {
+                        if (conf->fl_type == lock->fl_type) {
+                                sum = add_locks (lock, conf);
+
+                                sum->fd         = lock->fd;
+
+                                __delete_client_lock (conf);
+                                __destroy_client_lock (conf);
+
+                                __destroy_client_lock (lock);
+                                __insert_and_merge (fdctx, sum);
+
+                                return;
+                        } else {
+                                sum = add_locks (lock, conf);
+
+                                sum->fd         = conf->fd;
+                                sum->owner      = conf->owner;
+
+                                v = subtract_locks (sum, lock);
+
+                                __delete_client_lock (conf);
+                                __destroy_client_lock (conf);
+
+                                __delete_client_lock (lock);
+                                __destroy_client_lock (lock);
+
+                                __destroy_client_lock (sum);
+
+                                for (i = 0; i < 3; i++) {
+                                        if (!v.locks[i])
+                                                continue;
+
+                                        INIT_LIST_HEAD (&v.locks[i]->list);
+                                        __insert_and_merge (fdctx,
+                                                            v.locks[i]);
+                                }
+
+                                __delete_unlck_locks (fdctx);
+                                return;
+                        }
+                }
+
+                if (lock->fl_type == F_UNLCK) {
+                        continue;
+                }
+
+                if ((conf->fl_type == F_RDLCK) && (lock->fl_type == F_RDLCK)) {
+                        __insert_lock (fdctx, lock);
+                        return;
+                }
+        }
+
+        /* no conflicts, so just insert */
+        if (lock->fl_type != F_UNLCK) {
+                __insert_lock (fdctx, lock);
+        } else {
+                __destroy_client_lock (lock);
+        }
+}
+
+static void
+client_setlk (clnt_fd_ctx_t *fdctx, client_posix_lock_t *lock)
+{
+        pthread_mutex_lock (&fdctx->mutex);
+        {
+                __insert_and_merge (fdctx, lock);
+        }
+        pthread_mutex_unlock (&fdctx->mutex);
+
+        return;
+}
+
+static void
+destroy_client_lock (client_posix_lock_t *lock)
+{
+        GF_FREE (lock);
+}
+
+int32_t
+delete_granted_locks_owner (fd_t *fd, uint64_t owner)
+{
+        clnt_fd_ctx_t     *fdctx = NULL;
+        client_posix_lock_t *lock  = NULL;
+        client_posix_lock_t *tmp   = NULL;
+        xlator_t            *this  = NULL;
+
+        struct list_head delete_list;
+        int ret   = 0;
+        int count = 0;
+
+        INIT_LIST_HEAD (&delete_list);
+        this = THIS;
+        fdctx = this_fd_get_ctx (fd, this);
+        if (!fdctx) {
+                gf_log (this->name, GF_LOG_DEBUG,
+                        "fdctx not valid");
+                ret = -1;
+                goto out;
+        }
+
+        pthread_mutex_lock (&fdctx->mutex);
+        {
+                list_for_each_entry_safe (lock, tmp, &fdctx->lock_list, list) {
+                        if (lock->owner == owner) {
+                                list_del_init (&lock->list);
+                                list_add_tail (&lock->list, &delete_list);
+                                count++;
+                        }
+                }
+        }
+        pthread_mutex_unlock (&fdctx->mutex);
+
+        list_for_each_entry_safe (lock, tmp, &delete_list, list) {
+                list_del_init (&lock->list);
+                destroy_client_lock (lock);
+        }
+
+/* FIXME: Need to actually print the locks instead of count */
+        gf_log (this->name, GF_LOG_DEBUG,
+                "Number of locks cleared=%d", count);
+
+out:
+        return ret;
+}
+
+int32_t
+delete_granted_locks_fd (clnt_fd_ctx_t *fdctx)
+{
+        client_posix_lock_t *lock = NULL;
+        client_posix_lock_t *tmp = NULL;
+        xlator_t            *this = NULL;
+
+        struct list_head delete_list;
+        int ret   = 0;
+        int count = 0;
+
+        INIT_LIST_HEAD (&delete_list);
+        this = THIS;
+
+        pthread_mutex_lock (&fdctx->mutex);
+        {
+                list_splice_init (&fdctx->lock_list, &delete_list);
+        }
+        pthread_mutex_unlock (&fdctx->mutex);
+
+        list_for_each_entry_safe (lock, tmp, &delete_list, list) {
+                list_del_init (&lock->list);
+                count++;
+                destroy_client_lock (lock);
+        }
+
+        /* FIXME: Need to actually print the locks instead of count */
+        gf_log (this->name, GF_LOG_DEBUG,
+                "Number of locks cleared=%d", count);
+
+        return  ret;
+}
+
+static void
+client_mark_bad_fd (fd_t *fd, clnt_fd_ctx_t *fdctx)
+{
+        xlator_t *this = NULL;
+
+        this = THIS;
+        if (fdctx)
+                fdctx->remote_fd = -1;
+        this_fd_set_ctx (fd, this, NULL, fdctx);
+}
+
+int32_t
+client_cmd_to_gf_cmd (int32_t cmd, int32_t *gf_cmd)
+{
+        int ret = 0;
+
+        if (cmd == F_GETLK || cmd == F_GETLK64)
+                *gf_cmd = GF_LK_GETLK;
+        else if (cmd == F_SETLK || cmd == F_SETLK64)
+                *gf_cmd = GF_LK_SETLK;
+        else if (cmd == F_SETLKW || cmd == F_SETLKW64)
+                *gf_cmd = GF_LK_SETLKW;
+        else if (cmd == F_RESLK_LCK)
+                *gf_cmd = GF_LK_RESLK_LCK;
+        else if (cmd == F_RESLK_LCKW)
+                *gf_cmd = GF_LK_RESLK_LCKW;
+        else if (cmd == F_RESLK_UNLCK)
+                *gf_cmd = GF_LK_RESLK_UNLCK;
+        else
+                ret = -1;
+
+        return ret;
+
+}
+
+static client_posix_lock_t *
+new_client_lock (struct flock *flock, uint64_t owner,
+                 int32_t cmd, fd_t *fd)
+{
+        client_posix_lock_t *new_lock = NULL;
+        xlator_t            *this = NULL;
+
+
+        this = THIS;
+        new_lock = GF_CALLOC (1, sizeof (*new_lock),
+                              gf_client_mt_clnt_lock_t);
+        if (!new_lock) {
+                gf_log (this->name, GF_LOG_ERROR,
+                        "Out of memory");
+                goto out;
+        }
+
+        INIT_LIST_HEAD (&new_lock->list);
+        new_lock->fd = fd;
+        memcpy (&new_lock->user_flock, flock, sizeof (struct flock));
+
+        new_lock->fl_type  = flock->l_type;
+        new_lock->fl_start = flock->l_start;
+
+	if (flock->l_len == 0)
+		new_lock->fl_end = LLONG_MAX;
+	else
+		new_lock->fl_end = flock->l_start + flock->l_len - 1;
+
+        new_lock->owner = owner;
+        new_lock->cmd = cmd; /* Not really useful */
+
+
+out:
+        return new_lock;
+}
+
+void
+client_save_number_fds (clnt_conf_t *conf, int count)
+{
+        LOCK (&conf->rec_lock);
+        {
+                conf->reopen_fd_count = count;
+        }
+        UNLOCK (&conf->rec_lock);
+}
+
+int
+client_add_lock_for_recovery (fd_t *fd, struct flock *flock, uint64_t owner,
+                              int32_t cmd)
+{
+        clnt_fd_ctx_t       *fdctx = NULL;
+        xlator_t            *this  = NULL;
+        client_posix_lock_t *lock  = NULL;
+        clnt_conf_t         *conf  = NULL;
+
+        int ret = 0;
+
+        this = THIS;
+        conf = this->private;
+
+        pthread_mutex_lock (&conf->lock);
+        {
+                fdctx = this_fd_get_ctx (fd, this);
+        }
+        pthread_mutex_unlock (&conf->lock);
+
+        if (!fdctx) {
+                gf_log (this->name, GF_LOG_DEBUG,
+                        "failed to get fd context. Marking as bad fd.");
+                ret = -EBADFD;
+                goto out;
+        }
+
+        lock = new_client_lock (flock, owner, cmd, fd);
+        if (!lock) {
+                gf_log (this->name, GF_LOG_ERROR,
+                        "Out of memory");
+                ret = -ENOMEM;
+                goto out;
+        }
+
+        client_setlk (fdctx, lock);
+
+out:
+        return ret;
+
+}
+
+static int
+construct_reserve_unlock (struct flock *lock, call_frame_t *frame,
+                          client_posix_lock_t *client_lock)
+{
+        GF_ASSERT (lock);
+        GF_ASSERT (frame);
+        GF_ASSERT (frame->root->lk_owner);
+
+        lock->l_type = F_UNLCK;
+        lock->l_start = 0;
+        lock->l_whence = SEEK_SET;
+        lock->l_len = 0; /* Whole file */
+        lock->l_pid = (uint64_t)frame->root;
+
+        frame->root->lk_owner = client_lock->owner;
+
+        return 0;
+}
+
+static int
+construct_reserve_lock (client_posix_lock_t *client_lock, call_frame_t *frame,
+                        struct flock *lock)
+{
+        GF_ASSERT (client_lock);
+
+        memcpy (lock, &(client_lock->user_flock), sizeof (struct flock));
+
+        frame->root->lk_owner = client_lock->owner;
+
+        return 0;
+}
+
+uint64_t
+decrement_reopen_fd_count (xlator_t *this, clnt_conf_t *conf)
+{
+        uint64_t fd_count = 0;
+
+        LOCK (&conf->rec_lock);
+        {
+                fd_count = --(conf->reopen_fd_count);
+        }
+        UNLOCK (&conf->rec_lock);
+
+        if (fd_count == 0) {
+                gf_log (this->name, GF_LOG_DEBUG,
+                        "All locks healed on the last fd - notifying CHILDUP");
+                client_notify_parents_child_up (this);
+        }
+
+        return fd_count;
+}
+
+int32_t
+client_remove_reserve_lock_cbk (call_frame_t *frame,
+                                void *cookie,
+                                xlator_t *this,
+                                int32_t op_ret,
+                                int32_t op_errno,
+                                struct flock *lock)
+{
+        clnt_local_t *local = NULL;
+        clnt_conf_t  *conf  = NULL;
+
+        uint64_t fd_count = 0;
+
+        local = frame->local;
+        conf  = this->private;
+
+        if (op_ret < 0) {
+                /* TODO: critical error describing recovery command
+                   and blanket on ops on fd */
+                gf_log (this->name, GF_LOG_CRITICAL,
+                        "Lock recovery failed with error msg=%s",
+                        strerror(op_errno));
+                goto cleanup;
+        }
+
+        gf_log (this->name, GF_LOG_DEBUG,
+                "Removing reserve lock was successful.");
+
+cleanup:
+        frame->local = NULL;
+        client_mark_bad_fd (local->client_lock->fd,
+                            local->fdctx);
+        destroy_client_lock (local->client_lock);
+        client_local_wipe (local);
+        STACK_DESTROY (frame->root);
+        fd_count = decrement_reopen_fd_count (this, conf);
+        gf_log (this->name, GF_LOG_DEBUG,
+                "Need to attempt lock recovery on %lld open fds",
+                (unsigned long long) fd_count);
+	return 0;
+}
+
+static void
+client_remove_reserve_lock (xlator_t *this, call_frame_t *frame,
+                            client_posix_lock_t *lock)
+{
+        struct flock unlock;
+        clnt_local_t *local = NULL;
+
+        local = frame->local;
+        construct_reserve_unlock (&unlock, frame, lock);
+
+        STACK_WIND (frame, client_remove_reserve_lock_cbk,
+                    this, this->fops->lk,
+                    lock->fd, F_RESLK_UNLCK, &unlock);
+}
+
+static client_posix_lock_t *
+get_next_recovery_lock (xlator_t *this, clnt_local_t *local)
+{
+        client_posix_lock_t *lock = NULL;
+
+        pthread_mutex_lock (&local->mutex);
+        {
+                if (list_empty (&local->lock_list)) {
+                        gf_log (this->name, GF_LOG_DEBUG,
+                                "lock-list empty");
+                        goto unlock;
+                }
+
+                lock = list_entry ((local->lock_list).next, typeof (*lock), list);
+                list_del_init (&lock->list);
+        }
+unlock:
+        pthread_mutex_unlock (&local->mutex);
+
+        return lock;
+
+}
+
+int32_t
+client_reserve_lock_cbk (call_frame_t *frame,
+		void *cookie,
+		xlator_t *this,
+		int32_t op_ret,
+		int32_t op_errno,
+		struct flock *lock)
+{
+
+        clnt_local_t *local = NULL;
+        clnt_conf_t  *conf  = NULL;
+
+        uint64_t fd_count = 0;
+
+        local = frame->local;
+        conf  = this->private;
+
+        /* Got the reserve lock. Check if lock is grantable and proceed
+           with the real lk call */
+
+        if (op_ret >= 0) {
+                /* Lock is grantable if flock reflects a successful getlk() call*/
+                if (lock->l_type == F_UNLCK && lock->l_pid) {
+                        gf_log (this->name, GF_LOG_DEBUG,
+                                "Got the reservelk, but the lock is not grantable. ");
+                        client_remove_reserve_lock (this, frame, local->client_lock);
+                        goto out;
+                }
+
+                gf_log (this->name, GF_LOG_DEBUG,
+                        "Reserve Lock succeeded");
+                client_send_recovery_lock (frame, this, local->client_lock);
+                goto out;
+        }
+
+        /* Somebody else has a reserve lk. Lock conflict detected.
+           Mark fd as bad */
+
+        gf_log (this->name, GF_LOG_DEBUG,
+                "Reservelk OP failed. Aborting lock recovery and marking bad fd");
+
+        client_mark_bad_fd (local->client_lock->fd,
+                            local->fdctx);
+        destroy_client_lock (local->client_lock);
+        frame->local = NULL;
+        client_local_wipe (local);
+        STACK_DESTROY (frame->root);
+        fd_count = decrement_reopen_fd_count (this, conf);
+        gf_log (this->name, GF_LOG_DEBUG,
+                "Need to attempt lock recovery on %lld open fds",
+                (unsigned long long) fd_count);
+
+out:
+	return 0;
+}
+
+int32_t
+client_recovery_lock_cbk (call_frame_t *frame,
+                          void *cookie,
+                          xlator_t *this,
+                          int32_t op_ret,
+                          int32_t op_errno,
+                          struct flock *lock)
+{
+        clnt_local_t *local = NULL;
+        clnt_fd_ctx_t *fdctx = NULL;
+        clnt_conf_t   *conf  = NULL;
+        client_posix_lock_t *next_lock = NULL;
+
+        struct flock reserve_flock;
+        uint64_t fd_count = 0;
+
+        local = frame->local;
+        conf  = this->private;
+
+        if (op_ret < 0) {
+                /* TODO: critical error describing recovery command
+                   and blanket on ops on fd */
+                gf_log (this->name, GF_LOG_CRITICAL,
+                        "Lock recovery failed with error msg=%s",
+                        strerror(op_errno));
+
+                client_mark_bad_fd (local->client_lock->fd,
+                                    local->fdctx);
+                goto cleanup;
+
+                /* Lock recovered. Continue with reserve lock for next lock */
+        } else {
+                gf_log (this->name, GF_LOG_DEBUG,
+                        "lock recovered successfully -  Continuing with next lock.");
+
+                next_lock = get_next_recovery_lock (this, local);
+                if (!next_lock) {
+                        gf_log (this->name, GF_LOG_DEBUG,
+                                "All locks recovered on fd");
+                        goto cleanup;
+                }
+
+                construct_reserve_lock (next_lock, frame, &reserve_flock);
+                local->fdctx       = fdctx;
+                local->client_lock = next_lock;
+
+                STACK_WIND (frame, client_reserve_lock_cbk,
+                            this, this->fops->lk,
+                            next_lock->fd, F_RESLK_LCK, &reserve_flock);
+                goto out;
+
+        }
+
+cleanup:
+        frame->local = NULL;
+        client_local_wipe (local);
+        if (local->client_lock)
+                destroy_client_lock (local->client_lock);
+        STACK_DESTROY (frame->root);
+        fd_count = decrement_reopen_fd_count (this, conf);
+        gf_log (this->name, GF_LOG_DEBUG,
+                "Need to attempt lock recovery on %lld open fds",
+                (unsigned long long) fd_count);
+
+out:
+	return 0;
+}
+
+static int
+client_send_recovery_lock (call_frame_t *frame, xlator_t *this,
+                           client_posix_lock_t *lock)
+{
+
+        frame->root->lk_owner = lock->owner;
+
+        /* Send all locks as F_SETLK to prevent the frame
+           from blocking if there is a conflict */
+
+        STACK_WIND (frame, client_recovery_lock_cbk,
+                    this, this->fops->lk,
+                    lock->fd, F_SETLK,
+                    &(lock->user_flock));
+
+        return 0;
+}
+
+static int
+client_lockrec_init (clnt_fd_ctx_t *fdctx, clnt_local_t *local)
+{
+
+        INIT_LIST_HEAD (&local->lock_list);
+        pthread_mutex_init (&local->mutex, NULL);
+
+        pthread_mutex_lock (&fdctx->mutex);
+        {
+                list_splice_init (&fdctx->lock_list, &local->lock_list);
+        }
+        pthread_mutex_unlock (&fdctx->mutex);
+
+        return 0;
+}
+
+int
+client_attempt_lock_recovery (xlator_t *this, clnt_fd_ctx_t *fdctx)
+{
+        call_frame_t        *frame = NULL;
+        clnt_local_t      *local = NULL;
+        client_posix_lock_t *lock  = NULL;
+
+        struct flock reserve_flock;
+        int ret = 0;
+
+        local = GF_CALLOC (1, sizeof (*local), gf_client_mt_clnt_local_t);
+        if (!local) {
+                gf_log (this->name, GF_LOG_ERROR,
+                        "Out of memory");
+                ret = -ENOMEM;
+                goto out;
+        }
+
+        client_lockrec_init (fdctx, local);
+
+        lock = get_next_recovery_lock (this, local);
+        if (!lock) {
+                gf_log (this->name, GF_LOG_DEBUG,
+                        "No locks on fd");
+                ret = -1;
+                goto out;
+        }
+
+        frame = create_frame (this, this->ctx->pool);
+        if (!frame) {
+                gf_log (this->name, GF_LOG_ERROR,
+                        "Out of memory");
+                ret = -1;
+                goto out;
+        }
+
+        construct_reserve_lock (lock, frame, &reserve_flock);
+
+        local->fdctx       = fdctx;
+        local->client_lock = lock;
+
+        STACK_WIND (frame, client_reserve_lock_cbk,
+                    this, this->fops->lk,
+                    lock->fd, F_RESLK_LCK, &reserve_flock);
+
+out:
+        return ret;
+
+
+}
+
+int32_t
+client_dump_locks (char *name, inode_t *inode,
+                   dict_t *dict)
+{
+        int     ret = 0;
+        char    dict_string[256];
+
+        ret = dump_client_locks (inode);
+        snprintf (dict_string, 256, "%d locks dumped in log file", ret);
+
+        dict = dict_new ();
+        if (!dict) {
+                gf_log (THIS->name, GF_LOG_DEBUG,
+                        "Out of memory");
+                ret = -1;
+                goto out;
+        }
+
+        ret = dict_set_str (dict, "trusted.glusterfs.clientlk-dump", dict_string);
+        if (ret) {
+                gf_log (THIS->name, GF_LOG_DEBUG,
+                        "Could not set dict with %s", CLIENT_DUMP_LOCKS);
+                goto out;
+        }
+
+out:
+        return ret;
+}
+
+int32_t
+is_client_dump_locks_cmd (char *name)
+{
+        int ret = 0;
+
+        if (strcmp (name, CLIENT_DUMP_LOCKS) == 0)
+                ret = 1;
+
+        return ret;
+}