Re: [take 3] pohmelfs: call for inclusion

[Evgeniy Polyakov]

On Fri, Mar 16, 2012 at 06:29:13AM -0700, Joe Perches (joe@xxxxxxxxxxx) wrote:
> On Fri, 2012-03-16 at 16:18 +0400, Evgeniy Polyakov wrote:
> > I'm please to announce new and completely rewritten distributed
> > filesystem - POHMELFS
> 
> Unfortunately, it doesn't compile against -next.

Here is the fixed version

diff --git a/fs/Kconfig b/fs/Kconfig
index d621f02..d7b8308 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -261,6 +261,7 @@ config NFS_COMMON
 source "net/sunrpc/Kconfig"
 source "fs/ceph/Kconfig"
 source "fs/cifs/Kconfig"
+source "fs/pohmelfs/Kconfig"
 source "fs/ncpfs/Kconfig"
 source "fs/coda/Kconfig"
 source "fs/afs/Kconfig"
diff --git a/fs/Makefile b/fs/Makefile
index 93804d4..a2a819f 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -124,3 +124,4 @@ obj-$(CONFIG_GFS2_FS)           += gfs2/
 obj-y				+= exofs/ # Multiple modules
 obj-$(CONFIG_CEPH_FS)		+= ceph/
 obj-$(CONFIG_PSTORE)		+= pstore/
+obj-$(CONFIG_POHMELFS)		+= pohmelfs/
diff --git a/fs/pohmelfs/Kconfig b/fs/pohmelfs/Kconfig
new file mode 100644
index 0000000..6358362
--- /dev/null
+++ b/fs/pohmelfs/Kconfig
@@ -0,0 +1,11 @@
+config POHMELFS
+	tristate "POHMELFS distributed filesystem"
+	depends on INET && EXPERIMENTAL
+	select CRYPTO_HASH
+	help
+	  POHMELFS is a POSIX frontend to Elliptics network
+
+	  Elliptics is a key/value storage, which by default implements
+	  distributed hash table structure.
+
+	  More information can be found at http://www.ioremap.net/projects/elliptics
diff --git a/fs/pohmelfs/Makefile b/fs/pohmelfs/Makefile
new file mode 100644
index 0000000..f38002d
--- /dev/null
+++ b/fs/pohmelfs/Makefile
@@ -0,0 +1,7 @@
+#
+# Makefile for the linux pohmel filesystem routines.
+#
+
+obj-$(CONFIG_POHMELFS) += pohmelfs.o
+
+pohmelfs-y := dir.o file.o inode.o net.o route.o super.o trans.o symlink.o stat.o pool.o
diff --git a/fs/pohmelfs/Module.symvers b/fs/pohmelfs/Module.symvers
new file mode 100644
index 0000000..e69de29
diff --git a/fs/pohmelfs/README b/fs/pohmelfs/README
new file mode 100644
index 0000000..2e42d5a
--- /dev/null
+++ b/fs/pohmelfs/README
@@ -0,0 +1,84 @@
+Pohmelfs is a POSIX frontend to elliptics distributed network build on top of DHT design
+You may find more about elliptics at http://www.ioremap.net/projects/elliptics
+Or example pohmelfs raid1 configuration at http://www.ioremap.net/node/535
+
+Here I will desribe pohmelfs mount options
+
+server=addr:port:family
+Remote node to connect (family may be 2 for IPv4 and 6 for IPv6)
+You may specify multiple nodes, usually it is ok to put here only subset
+of all remote nodes in cluster, pohmelfs will automatically discover other nodes
+
+fsid=<string>
+Filesystem ID - you may have multiple filesystems in the same elliptics cluster
+This ID may be thought of as container or namespace identity
+By default it is 'pohmelfs' (without quotes)
+
+sync_timeout=<int>
+Timeout in seconds used to synchronize local cache with the storage
+In particular all pending writes will be flushed to storage.
+If you read directory, which previously was read more than 'sync_timeout' seconds,
+it will be reread from storage, otherwise it will be read from local cache.
+The same logic _will_ apply to file content, right now once read, file will not
+be reread again until cache is dropped
+
+groups=<int>:<int>:...
+You may specify group IDs to store data to.
+One may think about group ID as replica ID, i.e. if you specify groups=1:2:3,
+each write will put data into groups with IDs 1, 2 and 3
+Read will fetch data from group 1 first, then 2 and 3
+If your replicas are not in sync, read will fetch elliptics metadata first,
+determine which replica has the most recent data, and will first try to read
+that group
+
+http_compat=<int>
+Specifies whether to use hash of full path name as inode ID (512 bits, sha512 is used)
+Provided number limits number of temporal pages allocated for path traversal, i.e.
+number of parallel pathes hashed
+Having something like 5-10 is ok for common cases
+
+readcsum/noreadcsum
+Specifies whether to turn on or off remote checksumming
+Having read csums for large files may be not a very good idea, since every read
+will force server to check whole file checksum, so for multi-gigabyte files read
+of the single page may take a while (until it is already cached)
+
+successful_write_count=<num>
+If not specified, write will be considered successful only if quorum
+(number of groups above / 2 + 1) of writes succeeded. You may alter this number
+by given option.
+Please note, that if write does not succeed, error may only be detected as returned
+value from sync() or close() syscall. Also, unsuccessful write is rescheduled and
+all its pages are redirtied again to be resent in future.
+
+keepalive_idle=<int>
+Number of seconds to wait before starting to send first TCP keepalive message
+
+keepalive_cnt=<int>
+Number of TCP keepalive messages to send before closing connection
+
+keepalive_interval=<int>
+Number of seconds between TCP keepalive messages
+
+readdir_allocation=<int>
+Number of pages allocated in one kmalloc() call when reading directory content from server
+Please note that higher-order allocations may fail, but low-ordered (like 1 or 2 pages)
+ends up in slow directory read for large directories.
+It may take up to couple of seconds to read directory with several thousands of entries,
+but usually because VFS will call ->lookup() method to every directory entry
+
+sync_on_close
+Forces flushing inode (and its data) to disk when file is closed
+
+connection_pool_size=<int>
+Number of simultaneous connections to every remote node. Connections are selected
+in round-robin fashion, but 1/4 of them (or at least one) are reserved for small-sized requests,
+which usually carry metadata messages like directory listing or file lookup requests.
+Messing them with bulk IO requests is always a bad idea.
+
+read_wait_timeout=<int>/write_wait_timeout=<int>
+Maximum number of milliseconds to wait for appropriate request to complete.
+By default both are equal to 5 seconds, which is not always a good idea especially for huge
+readahead, big cache writeback intervals and/or rather slow disks.
+These timeouts are used not only for IO requests, but also for metadata commands like
+directory listing or object lookup.
diff --git a/fs/pohmelfs/dir.c b/fs/pohmelfs/dir.c
new file mode 100644
index 0000000..fd11ff3
--- /dev/null
+++ b/fs/pohmelfs/dir.c
@@ -0,0 +1,1114 @@
+/*
+ * Copyright (C) 2011+ Evgeniy Polyakov <zbr@xxxxxxxxxxx>
+ */
+
+#include <linux/fs.h>
+#include <linux/dcache.h>
+#include <linux/quotaops.h>
+
+#include "pohmelfs.h"
+
+#define POHMELFS_LOOKUP_SCRIPT				"pohmelfs_lookup.py"
+#define POHMELFS_UNLINK_SCRIPT				"pohmelfs_unlink.py"
+#define POHMELFS_DATA_UNLINK_SCRIPT			"pohmelfs_data_unlink.py"
+#define POHMELFS_HARDLINK_SCRIPT			"pohmelfs_hardlink.py"
+#define POHMELFS_RENAME_SCRIPT				"pohmelfs_rename.py"
+#define POHMELFS_INODE_INFO_SCRIPT_INSERT		"pohmelfs_inode_info_insert.py"
+#define POHMELFS_READDIR_SCRIPT				"pohmelfs_readdir.py"
+#define POHMELFS_DENTRY_NAME_SCRIPT			"pohmelfs_dentry_name="
+
+static void pohmelfs_init_local(struct pohmelfs_inode *pi, struct inode *dir)
+{
+	struct inode *inode = &pi->vfs_inode;
+
+	inode_init_owner(inode, dir, inode->i_mode);
+	pi->local = 1;
+
+	mark_inode_dirty(inode);
+}
+
+static int pohmelfs_send_dentry_complete(struct pohmelfs_trans *t, struct pohmelfs_state *recv)
+{
+	struct pohmelfs_inode *pi = pohmelfs_inode(t->inode);
+	struct pohmelfs_wait *wait = t->priv;
+	struct dnet_cmd *cmd = &recv->cmd;
+	unsigned long long trans = cmd->trans & ~DNET_TRANS_REPLY;
+
+	if (cmd->flags & DNET_FLAGS_MORE) {
+		if (cmd->status == 0 && cmd->size != sizeof(struct dnet_attr) + 2)
+			cmd->status = -EINVAL;
+
+		pr_debug("pohmelfs: %s: pohmelfs_send_dentry_complete: %llu, cmd_size: %llu, flags: %x, status: %d\n",
+				pohmelfs_dump_id(pi->id.id), trans, cmd->size, cmd->flags, cmd->status);
+
+		if (!cmd->status)
+			wait->condition = 1;
+		else
+			wait->condition = cmd->status;
+		wake_up(&wait->wq);
+	}
+
+	return 0;
+}
+
+static int pohmelfs_send_inode_info_init(struct pohmelfs_trans *t)
+{
+	struct pohmelfs_wait *wait = t->priv;
+
+	pohmelfs_wait_get(wait);
+	return 0;
+}
+
+static void pohmelfs_send_inode_info_destroy(struct pohmelfs_trans *t)
+{
+	struct pohmelfs_wait *wait = t->priv;
+
+	if (!wait->condition)
+		wait->condition = 1;
+	wake_up(&wait->wq);
+	pohmelfs_wait_put(wait);
+}
+
+static int pohmelfs_lookup_complete(struct pohmelfs_trans *t, struct pohmelfs_state *recv)
+{
+	struct pohmelfs_inode *parent = pohmelfs_inode(t->inode);
+	struct pohmelfs_wait *wait = t->priv;
+	struct dnet_cmd *cmd = &recv->cmd;
+	unsigned long long trans = cmd->trans & ~DNET_TRANS_REPLY;
+	int err = cmd->status;
+
+	if (err)
+		goto err_out_exit;
+
+	if (cmd->flags & DNET_FLAGS_MORE) {
+		struct pohmelfs_sb *psb = pohmelfs_sb(t->inode->i_sb);
+		struct pohmelfs_inode_info *info;
+		struct pohmelfs_inode *pi;
+
+		if (cmd->size != sizeof(struct dnet_attr) + sizeof(struct pohmelfs_inode_info)) {
+			err = -ENOENT;
+			goto err_out_exit;
+		}
+
+		pr_debug("pohmelfs: %s: pohmelfs_lookup_complete: %llu, size: %llu, min size: %zu, flags: %x, status: %d\n",
+				pohmelfs_dump_id(parent->id.id), trans, cmd->size,
+				sizeof(struct dnet_attr) + sizeof(struct pohmelfs_inode_info), cmd->flags, cmd->status);
+
+
+		info = t->recv_data + sizeof(struct dnet_attr);
+		pohmelfs_convert_inode_info(info);
+
+		pi = pohmelfs_existing_inode(psb, info);
+		if (IS_ERR(pi)) {
+			err = PTR_ERR(pi);
+
+			if (err != -EEXIST)
+				goto err_out_exit;
+
+			err = 0;
+			pi = pohmelfs_sb_inode_lookup(psb, &info->id);
+			if (!pi) {
+				err = -ENOENT;
+				goto err_out_exit;
+			}
+
+			pohmelfs_fill_inode(&pi->vfs_inode, info);
+		}
+
+		wait->ret = pi;
+	}
+
+err_out_exit:
+	if (err)
+		wait->condition = err;
+	else
+		wait->condition = 1;
+	wake_up(&wait->wq);
+
+	return 0;
+}
+
+int pohmelfs_send_script_request(struct pohmelfs_inode *parent, struct pohmelfs_script_req *req)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(parent->vfs_inode.i_sb);
+	struct pohmelfs_wait *wait;
+	struct pohmelfs_io *pio;
+	struct dnet_exec *e;
+	int script_len;
+	long ret;
+	int err;
+
+	/* 2 commas, \n and 0-byte, which is accounted in sizeof(string) */
+	script_len = sizeof(POHMELFS_DENTRY_NAME_SCRIPT) + req->obj_len + 3;
+
+	wait = pohmelfs_wait_alloc(parent);
+	if (!wait) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	pio = kmem_cache_zalloc(pohmelfs_io_cache, GFP_NOIO);
+	if (!pio) {
+		err = -ENOMEM;
+		goto err_out_wait_put;
+	}
+
+	e = kmalloc(sizeof(struct dnet_exec) + req->script_namelen + script_len + req->binary_size, GFP_NOIO);
+	if (!e) {
+		err = -ENOMEM;
+		goto err_out_free_pio;
+	}
+
+	memset(e, 0, sizeof(struct dnet_exec));
+
+	snprintf(e->data, req->script_namelen + script_len, "%s%s'%s'\n", req->script_name, POHMELFS_DENTRY_NAME_SCRIPT, req->obj_name);
+	script_len--; /* do not include last 0-byte in the script */
+
+	memcpy(e->data + req->script_namelen + script_len, req->binary, req->binary_size);
+
+	e->type = DNET_EXEC_PYTHON_SCRIPT_NAME;
+	e->name_size = req->script_namelen;
+	e->script_size = script_len;
+	e->binary_size = req->binary_size;
+	dnet_convert_exec(e);
+
+	pio->pi = parent;
+	pio->id = req->id;
+	pio->group_id = req->group_id;
+	pio->cflags = DNET_FLAGS_NEED_ACK | req->cflags;
+
+	pio->cmd = DNET_CMD_EXEC;
+	pio->size = sizeof(struct dnet_exec) + req->script_namelen + script_len + req->binary_size;
+	pio->data = e;
+	pio->priv = wait;
+	pio->cb.init = pohmelfs_send_inode_info_init;
+	pio->cb.destroy = pohmelfs_send_inode_info_destroy;
+	pio->cb.complete = req->complete;
+
+	if (pio->group_id) {
+		err = pohmelfs_send_buf_single(pio, NULL);
+	} else {
+		err = pohmelfs_send_buf(pio);
+	}
+	if (err)
+		goto err_out_free;
+
+	{
+		int len = 6;
+		char parent_id_str[len*2+1];
+
+		pr_debug("pohmelfs: SENT: %.*s: %s: inode->id: %s, ino: %lu, object: %s, binary size: %d, ret: %p, condition: %d\n",
+				req->script_namelen, req->script_name,
+				pohmelfs_dump_id(req->id->id),
+				pohmelfs_dump_id_len_raw(parent->id.id, len, parent_id_str),
+				parent->vfs_inode.i_ino, req->obj_name, req->binary_size,
+				req->ret, req->ret_cond);
+	}
+
+	if (req->sync) {
+		ret = wait_event_interruptible_timeout(wait->wq, wait->condition != 0, msecs_to_jiffies(psb->read_wait_timeout));
+		if (ret <= 0) {
+			err = ret;
+			if (ret == 0)
+				err = -ETIMEDOUT;
+			goto err_out_free;
+		}
+
+		if (wait->condition < 0)
+			err = wait->condition;
+
+		req->ret = wait->ret;
+		req->ret_cond = wait->condition;
+	}
+
+err_out_free:
+	kfree(e);
+err_out_free_pio:
+	kmem_cache_free(pohmelfs_io_cache, pio);
+err_out_wait_put:
+	pohmelfs_wait_put(wait);
+err_out_exit:
+	{
+		int len = 6;
+		char parent_id_str[len*2+1];
+
+		pr_debug("pohmelfs: DONE: %.*s: %s: inode->id: %s, ino: %lu, object: %s, binary size: %d, ret: %p, condition: %d, err: %d\n",
+				req->script_namelen, req->script_name,
+				pohmelfs_dump_id(req->id->id),
+				pohmelfs_dump_id_len_raw(parent->id.id, len, parent_id_str),
+				parent->vfs_inode.i_ino, req->obj_name, req->binary_size,
+				req->ret, req->ret_cond, err);
+	}
+	return err;
+}
+
+int pohmelfs_send_dentry(struct pohmelfs_inode *pi, struct dnet_raw_id *id, const char *sname, int len, int sync)
+{
+	struct pohmelfs_script_req req;
+	struct pohmelfs_dentry *pd;
+	int err;
+
+	if (!len) {
+		err = -EINVAL;
+		goto err_out_exit;
+	}
+
+	pd = kmem_cache_alloc(pohmelfs_dentry_cache, GFP_NOIO);
+	if (!pd) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	pd->parent_id = *id;
+	pd->disk.id = pi->id;
+	pd->disk.ino = cpu_to_le64(pi->vfs_inode.i_ino);
+	pd->disk.type = (pi->vfs_inode.i_mode >> 12) & 15;
+	pd->disk.len = len;
+
+	memset(&req, 0, sizeof(struct pohmelfs_script_req));
+
+	req.id = id;
+
+	req.script_name = POHMELFS_INODE_INFO_SCRIPT_INSERT;
+	req.script_namelen = sizeof(POHMELFS_INODE_INFO_SCRIPT_INSERT) - 1; /* not including 0-byte */
+
+	req.obj_name = (char *)sname;
+	req.obj_len = len;
+
+	req.binary = pd;
+	req.binary_size = sizeof(struct pohmelfs_dentry);
+
+	req.group_id = 0;
+	req.id = id;
+
+	req.sync = sync;
+	req.complete = pohmelfs_send_dentry_complete;
+
+	err = pohmelfs_send_script_request(pi, &req);
+	if (err)
+		goto err_out_free;
+
+err_out_free:
+	kmem_cache_free(pohmelfs_dentry_cache, pd);
+err_out_exit:
+	return err;
+}
+
+static int pohmelfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
+		struct nameidata *nd)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(dir->i_sb);
+	struct pohmelfs_inode *pi;
+	int err;
+
+	inode_inc_link_count(dir);
+
+	pi = pohmelfs_new_inode(psb, mode);
+	if (IS_ERR(pi)) {
+		err = PTR_ERR(pi);
+		goto err_out_exit;
+	}
+	pohmelfs_init_local(pi, dir);
+	mark_inode_dirty(dir);
+
+	/*
+	 * calling d_instantiate() implies that
+	 * ->lookup() used d_splice_alias() with NULL inode
+	 *  when it failed to find requested object
+	 */
+	d_instantiate(dentry, &pi->vfs_inode);
+	if (psb->http_compat)
+		pohmelfs_http_compat_id(pi);
+
+	err = pohmelfs_send_dentry(pi, &pohmelfs_inode(dir)->id, dentry->d_name.name, dentry->d_name.len, 1);
+	if (err)
+		goto err_out_exit;
+
+	pr_debug("pohmelfs: create: %s, ino: %lu, parent dir: %lu, object: %s\n",
+			pohmelfs_dump_id(pi->id.id), pi->vfs_inode.i_ino,
+			dir->i_ino, dentry->d_name.name);
+
+	return 0;
+
+err_out_exit:
+	inode_dec_link_count(dir);
+	return err;
+}
+
+static struct pohmelfs_inode *pohmelfs_lookup_group(struct inode *dir, struct dentry *dentry, int group_id)
+{
+	struct pohmelfs_inode *parent = pohmelfs_inode(dir);
+	struct pohmelfs_script_req req;
+	struct pohmelfs_inode *pi;
+	int err;
+
+	memset(&req, 0, sizeof(struct pohmelfs_script_req));
+
+	req.script_name = POHMELFS_LOOKUP_SCRIPT;
+	req.script_namelen = sizeof(POHMELFS_LOOKUP_SCRIPT) - 1; /* not including 0-byte */
+
+	req.obj_name = (char *)dentry->d_name.name;
+	req.obj_len = dentry->d_name.len;
+
+	req.binary = &parent->id;
+	req.binary_size = sizeof(struct dnet_raw_id);
+
+	req.id = &parent->id;
+	req.complete = pohmelfs_lookup_complete;
+
+	req.group_id = group_id;
+	req.sync = 1;
+	req.cflags = 0;
+
+	err = pohmelfs_send_script_request(parent, &req);
+	if (err)
+		goto err_out_exit;
+
+	pi = req.ret;
+	if (!pi) {
+		err = -ENOENT;
+		goto err_out_exit;
+	}
+
+	return pi;
+
+err_out_exit:
+	pr_debug("pohmelfs: pohmelfs_lookup_group: %s: group: %d: parent ino: %lu, name: %s: %d\n",
+		pohmelfs_dump_id(parent->id.id), group_id, parent->vfs_inode.i_ino, dentry->d_name.name, err);
+	return ERR_PTR(err);
+}
+
+static struct dentry *pohmelfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(dir->i_sb);
+	struct inode *inode = NULL;
+	struct pohmelfs_inode *pi;
+	int i, err = -ENOENT;
+
+	for (i = 0; i < psb->group_num; ++i) {
+		pi = pohmelfs_lookup_group(dir, dentry, psb->groups[i]);
+		if (IS_ERR(pi)) {
+			err = PTR_ERR(pi);
+			continue;
+		}
+
+		inode = &pi->vfs_inode;
+		err = 0;
+		break;
+	}
+
+	return d_splice_alias(inode, dentry);
+}
+
+static int pohmelfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(dir->i_sb);
+	struct pohmelfs_inode *pi;
+	int err;
+
+	inode_inc_link_count(dir);
+
+	pi = pohmelfs_new_inode(psb, mode | S_IFDIR);
+	if (IS_ERR(pi)) {
+		err = PTR_ERR(pi);
+		goto err_out_dir;
+	}
+	pohmelfs_init_local(pi, dir);
+	mark_inode_dirty(dir);
+
+	d_instantiate(dentry, &pi->vfs_inode);
+	if (psb->http_compat)
+		pohmelfs_http_compat_id(pi);
+
+	err = pohmelfs_send_dentry(pi, &pohmelfs_inode(dir)->id, dentry->d_name.name, dentry->d_name.len, 1);
+	if (err)
+		goto err_out_dir;
+
+	pr_debug("pohmelfs: mkdir: %s, ino: %lu, parent dir: %lu, object: %s, refcnt: %d\n",
+			pohmelfs_dump_id(pi->id.id), pi->vfs_inode.i_ino,
+			dir->i_ino, dentry->d_name.name, dentry->d_count);
+	return 0;
+
+err_out_dir:
+	inode_dec_link_count(dir);
+	return err;
+}
+
+static int pohmelfs_unlink(struct inode *dir, struct dentry *dentry)
+{
+	struct pohmelfs_inode *parent = pohmelfs_inode(dir);
+	struct inode *inode = dentry->d_inode;
+	struct pohmelfs_inode *pi = pohmelfs_inode(inode);
+	struct pohmelfs_script_req req;
+	int err;
+
+	inode->i_ctime = dir->i_ctime;
+	mark_inode_dirty(dir);
+
+	memset(&req, 0, sizeof(struct pohmelfs_script_req));
+
+	req.script_name = POHMELFS_UNLINK_SCRIPT;
+	req.script_namelen = sizeof(POHMELFS_UNLINK_SCRIPT) - 1; /* not including 0-byte */
+
+	req.obj_name = (char *)dentry->d_name.name;
+	req.obj_len = dentry->d_name.len;
+
+	req.binary = &parent->id;
+	req.binary_size = sizeof(struct dnet_raw_id);
+
+	req.group_id = 0;
+	req.id = &parent->id;
+	req.complete = pohmelfs_send_dentry_complete;
+
+	req.sync = 1;
+
+	err = pohmelfs_send_script_request(parent, &req);
+	if (err)
+		return err;
+
+	req.script_name = POHMELFS_DATA_UNLINK_SCRIPT;
+	req.script_namelen = sizeof(POHMELFS_DATA_UNLINK_SCRIPT) - 1; /* not including 0-byte */
+
+	req.binary = &pi->id;
+	req.binary_size = sizeof(struct dnet_raw_id);
+
+	return pohmelfs_send_script_request(parent, &req);
+}
+
+static int pohmelfs_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	return pohmelfs_unlink(dir, dentry);
+}
+
+struct pohmelfs_rename_req {
+	struct dnet_raw_id		old_dir_id;
+
+	struct pohmelfs_dentry		dentry;
+} __attribute__ ((packed));
+
+static int pohmelfs_rename(struct inode *old_dir, struct dentry *old_dentry,
+			struct inode *new_dir, struct dentry *new_dentry)
+{
+	struct pohmelfs_inode *old_parent = pohmelfs_inode(old_dir);
+	struct inode *inode = old_dentry->d_inode;
+	struct inode *new_inode = new_dentry->d_inode;
+	struct pohmelfs_inode *pi = pohmelfs_inode(inode);
+	struct pohmelfs_script_req req;
+	struct pohmelfs_rename_req *r;
+	int size = sizeof(struct pohmelfs_rename_req) + new_dentry->d_name.len;
+	int err;
+
+	pr_debug("pohmelfs: %s: rename: %.*s -> %.*s: mtime: %ld\n", pohmelfs_dump_id(pi->id.id),
+			old_dentry->d_name.len, old_dentry->d_name.name,
+			new_dentry->d_name.len, new_dentry->d_name.name,
+			inode->i_mtime.tv_sec);
+
+	if (pohmelfs_sb(inode->i_sb)->http_compat) {
+		err = -ENOTSUPP;
+		goto err_out_exit;
+	}
+
+	r = kzalloc(size, GFP_NOIO);
+	if (!r) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	r->old_dir_id = pohmelfs_inode(old_dir)->id;
+	r->dentry.parent_id = pohmelfs_inode(new_dir)->id;
+	r->dentry.disk.id = pohmelfs_inode(inode)->id;
+	r->dentry.disk.ino = cpu_to_le64(inode->i_ino);
+	r->dentry.disk.type = (inode->i_mode >> 12) & 15;
+	r->dentry.disk.len = new_dentry->d_name.len;
+
+	memcpy(r->dentry.disk.name, new_dentry->d_name.name, new_dentry->d_name.len);
+
+	memset(&req, 0, sizeof(struct pohmelfs_script_req));
+
+	req.script_name = POHMELFS_RENAME_SCRIPT;
+	req.script_namelen = sizeof(POHMELFS_RENAME_SCRIPT) - 1; /* not including 0-byte */
+
+	req.obj_name = (char *)old_dentry->d_name.name;
+	req.obj_len = old_dentry->d_name.len;
+
+	req.binary = r;
+	req.binary_size = size;
+
+	req.sync = 1;
+	req.group_id = 0;
+	req.id = &old_parent->id;
+	req.complete = pohmelfs_send_dentry_complete;
+
+	if (new_inode) {
+		new_inode->i_ctime = CURRENT_TIME_SEC;
+	}
+	inode->i_ctime = CURRENT_TIME_SEC;
+	mark_inode_dirty(inode);
+	mark_inode_dirty(new_dir);
+
+	err = pohmelfs_send_script_request(old_parent, &req);
+	if (err)
+		goto err_out_free;
+
+err_out_free:
+	kfree(r);
+err_out_exit:
+	return err;
+}
+
+static int pohmelfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(dir->i_sb);
+	struct pohmelfs_inode *parent = pohmelfs_inode(dir);
+	struct pohmelfs_inode *pi;
+	struct inode *inode;
+	unsigned len = strlen(symname)+1;
+	int err = 0;
+
+	inode_inc_link_count(dir);
+	pi = pohmelfs_new_inode(psb, S_IFLNK | S_IRWXUGO);
+	if (IS_ERR(pi)) {
+		err = PTR_ERR(pi);
+		goto err_out_exit;
+	}
+	inode = &pi->vfs_inode;
+	pohmelfs_init_local(pi, dir);
+	mark_inode_dirty(dir);
+
+	err = page_symlink(inode, symname, len);
+	if (err)
+		goto err_out_put;
+
+	d_instantiate(dentry, inode);
+	if (psb->http_compat)
+		pohmelfs_http_compat_id(pi);
+
+	err = pohmelfs_send_dentry(pi, &parent->id, dentry->d_name.name, dentry->d_name.len, 1);
+	if (err)
+		goto err_out_exit;
+
+	return 0;
+
+err_out_put:
+	iput(inode);
+err_out_exit:
+	inode_dec_link_count(dir);
+	return err;
+}
+
+static int pohmelfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
+{
+	struct inode *inode = old_dentry->d_inode;
+	struct pohmelfs_inode *parent = pohmelfs_inode(dir);
+	struct pohmelfs_inode *pi = pohmelfs_inode(inode);
+	struct pohmelfs_script_req req;
+	int err;
+
+	if (pohmelfs_sb(inode->i_sb)->http_compat) {
+		err = -ENOTSUPP;
+		goto err_out_exit;
+	}
+
+	dquot_initialize(dir);
+
+	inode->i_ctime = CURRENT_TIME_SEC;
+	inode_inc_link_count(inode);
+	ihold(inode);
+
+	err = pohmelfs_send_dentry(pi, &parent->id, dentry->d_name.name, dentry->d_name.len, 1);
+	if (err) {
+		goto err_out_put;
+	}
+
+	memset(&req, 0, sizeof(struct pohmelfs_script_req));
+
+	req.script_name = POHMELFS_HARDLINK_SCRIPT;
+	req.script_namelen = sizeof(POHMELFS_HARDLINK_SCRIPT) - 1; /* not including 0-byte */
+
+	req.obj_name = (char *)dentry->d_name.name;
+	req.obj_len = dentry->d_name.len;
+
+	req.binary = &pi->id;
+	req.binary_size = sizeof(struct dnet_raw_id);
+
+	req.group_id = 0;
+	req.id = &pi->id;
+	req.complete = pohmelfs_send_dentry_complete;
+
+	req.sync = 1;
+
+	err = pohmelfs_send_script_request(parent, &req);
+	if (err)
+		goto err_out_unlink;
+
+	mark_inode_dirty(dir);
+	mark_inode_dirty(inode);
+	d_instantiate(dentry, inode);
+	return 0;
+
+err_out_unlink:
+	req.binary = &parent->id;
+	req.script_name = POHMELFS_UNLINK_SCRIPT;
+	req.script_namelen = sizeof(POHMELFS_UNLINK_SCRIPT) - 1; /* not including 0-byte */
+	pohmelfs_send_script_request(parent, &req);
+err_out_put:
+	inode_dec_link_count(inode);
+	iput(inode);
+err_out_exit:
+	return err;
+}
+
+static int pohmelfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(dir->i_sb);
+	struct pohmelfs_inode *pi;
+	struct inode *inode;
+	int err;
+
+	if (!new_valid_dev(rdev))
+		return -EINVAL;
+
+	inode_inc_link_count(dir);
+	dquot_initialize(dir);
+
+	pi = pohmelfs_new_inode(psb, mode);
+	if (IS_ERR(pi)) {
+		err = PTR_ERR(pi);
+		goto err_out_exit;
+	}
+	inode = &pi->vfs_inode;
+	pohmelfs_init_local(pi, dir);
+	mark_inode_dirty(dir);
+
+	init_special_inode(inode, inode->i_mode, rdev);
+	inode->i_op = &pohmelfs_special_inode_operations;
+
+	d_instantiate(dentry, inode);
+	if (psb->http_compat)
+		pohmelfs_http_compat_id(pi);
+
+	err = pohmelfs_send_dentry(pi, &pohmelfs_inode(dir)->id, dentry->d_name.name, dentry->d_name.len, 1);
+	if (err)
+		goto err_out_exit;
+
+	return 0;
+
+err_out_exit:
+	inode_dec_link_count(dir);
+	return err;
+}
+
+const struct inode_operations pohmelfs_dir_inode_operations = {
+	.create		= pohmelfs_create,
+	.lookup 	= pohmelfs_lookup,
+	.mkdir		= pohmelfs_mkdir,
+	.unlink		= pohmelfs_unlink,
+	.rmdir		= pohmelfs_rmdir,
+	.rename		= pohmelfs_rename,
+	.symlink	= pohmelfs_symlink,
+	.link		= pohmelfs_link,
+	.mknod		= pohmelfs_mknod,
+};
+
+static int pohmelfs_readdir_complete(struct pohmelfs_trans *t, struct pohmelfs_state *recv)
+{
+	struct pohmelfs_inode *pi = pohmelfs_inode(t->inode);
+	struct pohmelfs_wait *wait = t->priv;
+	struct dnet_cmd *cmd = &recv->cmd;
+
+	pr_debug("pohmelfs: %s: readdir comlete: cmd size: %llu, flags: %x\n",
+			pohmelfs_dump_id(pi->id.id), (unsigned long long)cmd->size, cmd->flags);
+
+	if (cmd->flags & DNET_FLAGS_MORE) {
+		if (cmd->size > sizeof(struct dnet_attr)) {
+			wait->ret = t->recv_data;
+			wait->condition = cmd->size;
+
+			t->recv_data = NULL;
+			wake_up(&wait->wq);
+		}
+	} else {
+		if (!wait->condition) {
+			wait->condition = cmd->status;
+			if (!wait->condition)
+				wait->condition = 1;
+		}
+	}
+
+	return 0;
+}
+
+static int pohmelfs_dentry_add(struct dentry *parent_dentry, struct pohmelfs_inode *pi, char *name, int len)
+{
+	struct inode *inode = &pi->vfs_inode;
+	struct dentry *dentry, *old;
+	struct qstr str;
+	int err = 0;
+
+	str.name = name;
+	str.len = len;
+	str.hash = full_name_hash(str.name, str.len);
+
+	dentry = d_lookup(parent_dentry, &str);
+	if (dentry) {
+		err = -EEXIST;
+
+		dput(dentry);
+		goto err_out_exit;
+	}
+	/*
+	 * if things are ok, dentry has 2 references -
+	 * one in parent dir, and another its own,
+	 * which we should drop
+	 */
+	dentry = d_alloc(parent_dentry, &str);
+	if (!dentry) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	old = d_splice_alias(inode, dentry);
+	if (unlikely(old)) {
+		dput(dentry);
+		err = -EEXIST;
+	} else {
+		dput(dentry);
+	}
+
+err_out_exit:
+	return err;
+}
+
+static int pohmelfs_update_inode(struct dentry *parent_dentry, struct pohmelfs_inode_info *info, char *name)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(parent_dentry->d_inode->i_sb);
+	struct pohmelfs_inode *pi;
+	struct inode *inode;
+	int err = 0;
+
+	pi = pohmelfs_sb_inode_lookup(psb, &info->id);
+	if (pi) {
+		inode = &pi->vfs_inode;
+		pohmelfs_fill_inode(inode, info);
+	} else {
+		pi = pohmelfs_existing_inode(psb, info);
+		if (IS_ERR(pi)) {
+			err = PTR_ERR(pi);
+			goto err_out_exit;
+		}
+		inode = &pi->vfs_inode;
+	}
+
+	mutex_lock(&inode->i_mutex);
+	err = pohmelfs_dentry_add(parent_dentry, pi, name, info->namelen);
+	mutex_unlock(&inode->i_mutex);
+	if (err)
+		iput(inode);
+
+err_out_exit:
+	return err;
+}
+
+struct pohmelfs_fetch_info {
+	struct dentry		*parent;
+	struct kref		refcnt;
+	int			len;
+	char			name[0];
+};
+
+static void pohmelfs_fetch_inode_info_free(struct kref *kref)
+{
+	struct pohmelfs_fetch_info *fi = container_of(kref, struct pohmelfs_fetch_info, refcnt);
+
+	dput(fi->parent);
+	kfree(fi);
+}
+
+static void pohmelfs_fetch_inode_info_destroy(struct pohmelfs_trans *t)
+{
+	struct pohmelfs_fetch_info *fi = t->priv;
+
+	kref_put(&fi->refcnt, pohmelfs_fetch_inode_info_free);
+}
+
+static int pohmelfs_fetch_inode_info_init(struct pohmelfs_trans *t)
+{
+	struct pohmelfs_fetch_info *fi = t->priv;
+
+	kref_get(&fi->refcnt);
+	return 0;
+}
+
+static int pohmelfs_fetch_inode_info_complete(struct pohmelfs_trans *t, struct pohmelfs_state *recv)
+{
+	struct pohmelfs_fetch_info *fi = t->priv;
+	struct dnet_cmd *cmd = &recv->cmd;
+	struct pohmelfs_inode_info *info;
+	int err;
+
+	if (cmd->status)
+		return 0;
+
+	if (cmd->size < sizeof(struct dnet_attr) + sizeof(struct dnet_io_attr) + sizeof(struct pohmelfs_inode_info))
+		return 0;
+
+	info = t->recv_data + sizeof(struct dnet_attr) + sizeof(struct dnet_io_attr);
+	pohmelfs_convert_inode_info(info);
+
+	info->namelen = fi->len;
+	err = pohmelfs_update_inode(fi->parent, info, fi->name);
+
+	pr_debug("pohmelfs: %s: fetched: '%.*s': %d\n", pohmelfs_dump_id(cmd->id.id), fi->len, fi->name, err);
+	return 0;
+}
+
+static int pohmelfs_fetch_inode_info_group(struct dentry *parent, struct pohmelfs_inode *pi,
+		struct pohmelfs_dentry_disk *d, int *groups, int group_num)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(pi->vfs_inode.i_sb);
+	struct pohmelfs_io *pio;
+	struct pohmelfs_fetch_info *fi;
+	int err, i;
+
+	pio = kmem_cache_zalloc(pohmelfs_io_cache, GFP_NOIO);
+	if (!pio) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	fi = kmalloc(sizeof(struct pohmelfs_fetch_info) + d->len, GFP_NOIO);
+	if (!fi) {
+		err = -ENOMEM;
+		goto err_out_free;
+	}
+
+	memcpy(fi->name, d->name, d->len);
+	fi->len = d->len;
+	kref_init(&fi->refcnt);
+	fi->parent = dget(parent);
+
+	pio->pi = pi;
+	pio->id = &d->id;
+	pio->cmd = DNET_CMD_READ;
+	pio->cflags = DNET_FLAGS_NEED_ACK | DNET_FLAGS_NOLOCK;
+	if (psb->no_read_csum)
+		pio->ioflags = DNET_IO_FLAGS_NOCSUM;
+	pio->type = POHMELFS_INODE_COLUMN;
+	pio->cb.complete = pohmelfs_fetch_inode_info_complete;
+	pio->cb.init = pohmelfs_fetch_inode_info_init;
+	pio->cb.destroy = pohmelfs_fetch_inode_info_destroy;
+	pio->priv = fi;
+
+	err = -ENOENT;
+	for (i = 0; i < group_num; ++i) {
+		pio->group_id = groups[i];
+		err = pohmelfs_send_io_group(pio, groups[i]);
+		if (!err)
+			break;
+	}
+
+	kref_put(&fi->refcnt, pohmelfs_fetch_inode_info_free);
+err_out_free:
+	kmem_cache_free(pohmelfs_io_cache, pio);
+err_out_exit:
+	return err;
+}
+
+static int pohmelfs_fetch_inode_info(struct dentry *parent, struct pohmelfs_inode *pi, struct pohmelfs_dentry_disk *d)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(pi->vfs_inode.i_sb);
+	if (pi->groups)
+		return pohmelfs_fetch_inode_info_group(parent, pi, d, pi->groups, pi->group_num);
+	else
+		return pohmelfs_fetch_inode_info_group(parent, pi, d, psb->groups, psb->group_num);
+}
+
+static int pohmelfs_readdir_process(void *data, int size, struct file *filp, void *dirent, filldir_t filldir)
+{
+	struct dentry *dentry = filp->f_path.dentry, *child;
+	struct inode *dir = dentry->d_inode;
+	void *orig_data = data;
+	int orig_size = size;
+	struct qstr str;
+	int err = 0;
+
+	while (size > 0) {
+		struct pohmelfs_dentry_disk *d = data;
+
+		if (size < sizeof(struct pohmelfs_dentry_disk)) {
+			err = -EINVAL;
+			goto err_out_exit;
+		}
+
+		if (size < d->len) {
+			err = -EINVAL;
+			goto err_out_exit;
+		}
+
+		str.name = d->name;
+		str.len = d->len;
+		str.hash = full_name_hash(str.name, str.len);
+
+		child = d_lookup(dentry, &str);
+		pr_debug("pohmelfs: %s: child: %.*s/%.*s: %p\n",
+				pohmelfs_dump_id(d->id.id),
+				dentry->d_name.len, dentry->d_name.name,
+				d->len, d->name,
+				child);
+		if (!child) {
+			pohmelfs_fetch_inode_info(dentry, pohmelfs_inode(dir), d);
+		} else {
+			dput(child);
+		}
+
+		size -= sizeof(struct pohmelfs_dentry_disk) + d->len;
+		data += sizeof(struct pohmelfs_dentry_disk) + d->len;
+	}
+
+	data = orig_data;
+	size = orig_size;
+	while (size > 0) {
+		struct pohmelfs_dentry_disk *d = data;
+
+		err = filldir(dirent, d->name, d->len, filp->f_pos, le64_to_cpu(d->ino), d->type);
+		if (err)
+			return 0;
+
+		filp->f_pos += 1;
+		size -= sizeof(struct pohmelfs_dentry_disk) + d->len;
+		data += sizeof(struct pohmelfs_dentry_disk) + d->len;
+	}
+
+err_out_exit:
+	return err;
+}
+
+struct pohmelfs_readdir {
+	struct dnet_raw_id			id;
+	int					max_size;
+	int					fpos;
+};
+
+static void *pohmelfs_readdir_group(int group_id, struct file *filp, int *sizep)
+{
+	struct dentry *dentry = filp->f_path.dentry;
+	struct inode *dir = dentry->d_inode;
+	struct pohmelfs_sb *psb = pohmelfs_sb(dir->i_sb);
+	struct pohmelfs_inode *parent = pohmelfs_inode(dir);
+	struct pohmelfs_readdir rd;
+	struct pohmelfs_script_req req;
+	void *data;
+	int size;
+	int err;
+
+	memset(&req, 0, sizeof(struct pohmelfs_script_req));
+
+	req.script_name = POHMELFS_READDIR_SCRIPT;
+	req.script_namelen = sizeof(POHMELFS_READDIR_SCRIPT) - 1; /* not including 0-byte */
+
+	req.obj_name = (char *)dentry->d_name.name;
+	req.obj_len = dentry->d_name.len;
+
+	rd.id = parent->id;
+	rd.max_size = psb->readdir_allocation * PAGE_SIZE - sizeof(struct dnet_attr); /* cmd->size should fit one page */
+	rd.fpos = filp->f_pos - 2; /* account for . and .. */
+
+	req.binary = &rd;
+	req.binary_size = sizeof(struct pohmelfs_readdir);
+
+	req.id = &parent->id;
+	req.complete = pohmelfs_readdir_complete;
+	req.cflags = 0;
+
+	req.group_id = group_id;
+	req.sync = 1;
+
+	err = pohmelfs_send_script_request(parent, &req);
+	if (err < 0)
+		goto err_out_exit;
+
+	data = req.ret;
+	size = req.ret_cond;
+	if (!data || !size) {
+		err = -ENOENT;
+		goto err_out_exit;
+	}
+
+	*sizep = size;
+	return data;
+
+err_out_exit:
+	return ERR_PTR(err);
+}
+
+static int pohmelfs_dir_open(struct inode *dir, struct file *filp)
+{
+#if 0
+	struct pohmelfs_inode *pi = pohmelfs_inode(dir);
+
+	if (!pohmelfs_need_resync(pi))
+		return dcache_dir_open(dir, filp);
+#endif
+	filp->f_pos = 0;
+	return 0;
+}
+
+static int pohmelfs_dir_close(struct inode *inode, struct file *filp)
+{
+	if (filp->private_data)
+		return dcache_dir_close(inode, filp);
+	return 0;
+}
+
+static int pohmelfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
+{
+	struct dentry *dentry = filp->f_path.dentry;
+	struct inode *dir = dentry->d_inode;
+	struct pohmelfs_inode *pi = pohmelfs_inode(dir);
+	struct pohmelfs_sb *psb = pohmelfs_sb(dir->i_sb);
+	int i, err = -ENOENT;
+
+	if (filp->private_data) {
+		return dcache_readdir(filp, dirent, filldir);
+	}
+
+	if (filp->f_pos == 0) {
+		err = filldir(dirent, ".", 1, filp->f_pos, dir->i_ino, DT_DIR);
+		if (err)
+			return err;
+		filp->f_pos++;
+	}
+
+	if (filp->f_pos == 1) {
+		err = filldir(dirent, "..", 2, filp->f_pos, parent_ino(dentry), DT_DIR);
+		if (err)
+			return err;
+		filp->f_pos++;
+	}
+
+	for (i = 0; i < psb->group_num; ++i) {
+		int size;
+		void *data;
+
+		data = pohmelfs_readdir_group(psb->groups[i], filp, &size);
+		if (IS_ERR(data)) {
+			err = PTR_ERR(data);
+			continue;
+		}
+
+		pi->update = get_seconds();
+		err = pohmelfs_readdir_process(data + sizeof(struct dnet_attr), size - sizeof(struct dnet_attr), filp, dirent, filldir);
+		kfree(data);
+
+		break;
+	}
+
+	return err;
+}
+
+const struct file_operations pohmelfs_dir_fops = {
+	.open		= pohmelfs_dir_open,
+	.release	= pohmelfs_dir_close,
+	.read		= generic_read_dir,
+	.readdir	= pohmelfs_readdir,
+};
diff --git a/fs/pohmelfs/file.c b/fs/pohmelfs/file.c
new file mode 100644
index 0000000..c431543
--- /dev/null
+++ b/fs/pohmelfs/file.c
@@ -0,0 +1,474 @@
+/*
+ * Copyright (C) 2011+ Evgeniy Polyakov <zbr@xxxxxxxxxxx>
+ */
+
+#include <linux/fs.h>
+
+#include "pohmelfs.h"
+
+#define POHMELFS_READ_LATEST_GROUPS_SCRIPT		"pohmelfs_read_latest_groups.py"
+
+static int pohmelfs_write_init(struct pohmelfs_trans *t)
+{
+	struct pohmelfs_wait *wait = t->priv;
+
+	pohmelfs_wait_get(wait);
+	return 0;
+}
+
+static void pohmelfs_write_destroy(struct pohmelfs_trans *t)
+{
+	struct pohmelfs_wait *wait = t->priv;
+
+	wake_up(&wait->wq);
+	pohmelfs_wait_put(wait);
+}
+
+static int pohmelfs_write_complete(struct pohmelfs_trans *t, struct pohmelfs_state *recv)
+{
+	struct pohmelfs_wait *wait = t->priv;
+	struct pohmelfs_inode *pi = pohmelfs_inode(t->inode);
+	struct dnet_cmd *cmd = &recv->cmd;
+	unsigned long long trans = cmd->trans & ~DNET_TRANS_REPLY;
+
+	pr_debug("pohmelfs: %s: write complete: %llu, flags: %x, status: %d\n",
+			pohmelfs_dump_id(pi->id.id), trans, cmd->flags, cmd->status);
+
+	if (cmd->flags & DNET_FLAGS_MORE)
+		return 0;
+
+	wait->condition = cmd->status;
+	if (!wait->condition)
+		wait->condition = 1;
+
+	return 0;
+}
+
+static int pohmelfs_send_write_metadata(struct pohmelfs_inode *pi, struct pohmelfs_io *pio, struct pohmelfs_wait *wait)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(pi->vfs_inode.i_sb);
+	struct timespec ts = CURRENT_TIME;
+	struct dnet_meta_update *mu;
+	struct dnet_meta *m;
+	int err, size;
+	void *data;
+
+	size = sizeof(struct dnet_meta) * 4 +
+			sizeof(struct dnet_meta_check_status) +
+			sizeof(struct dnet_meta_update) +
+			psb->fsid_len +
+			psb->group_num * sizeof(int);
+
+	data = kzalloc(size, GFP_NOIO);
+	if (!data) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	m = data;
+	m->type = DNET_META_GROUPS;
+	m->size = psb->group_num * sizeof(int);
+	memcpy(m->data, psb->groups, m->size);
+	dnet_convert_meta(m);
+
+	m = (struct dnet_meta *)(m->data + le32_to_cpu(m->size));
+	m->type = DNET_META_NAMESPACE;
+	m->size = psb->fsid_len;
+	memcpy(m->data, psb->fsid, psb->fsid_len);
+	dnet_convert_meta(m);
+
+	m = (struct dnet_meta *)(m->data + le32_to_cpu(m->size));
+	m->type = DNET_META_UPDATE;
+	m->size = sizeof(struct dnet_meta_update);
+	mu = (struct dnet_meta_update *)m->data;
+	mu->tm.tsec = ts.tv_sec;
+	mu->tm.tnsec = ts.tv_nsec;
+	dnet_convert_meta_update(mu);
+	dnet_convert_meta(m);
+
+	m = (struct dnet_meta *)(m->data + le32_to_cpu(m->size));
+	m->type = DNET_META_CHECK_STATUS;
+	m->size = sizeof(struct dnet_meta_check_status);
+	/* do not fill, it will be updated on server */
+	dnet_convert_meta(m);
+
+	pio->pi = pi;
+	pio->id = &pi->id;
+	pio->cmd = DNET_CMD_WRITE;
+	pio->ioflags = DNET_IO_FLAGS_OVERWRITE | DNET_IO_FLAGS_META;
+	pio->cflags = DNET_FLAGS_NEED_ACK;
+	pio->type = 1;
+	pio->cb.init = pohmelfs_write_init;
+	pio->cb.destroy = pohmelfs_write_destroy;
+	pio->cb.complete = pohmelfs_write_complete;
+	pio->priv = wait;
+	pio->data = data;
+	pio->size = size;
+
+	err = pohmelfs_send_io(pio);
+	if (err)
+		goto err_out_free;
+
+err_out_free:
+	kfree(data);
+err_out_exit:
+	return err;
+}
+
+static int pohmelfs_write_command_complete(struct pohmelfs_trans *t, struct pohmelfs_state *recv)
+{
+	struct dnet_cmd *cmd = &recv->cmd;
+	struct pohmelfs_write_ctl *ctl = t->wctl;
+
+	if (cmd->flags & DNET_FLAGS_MORE)
+		return 0;
+
+	if (cmd->status == 0)
+		atomic_inc(&ctl->good_writes);
+	else {
+		struct inode *inode = t->inode;
+		struct pohmelfs_inode *pi = pohmelfs_inode(inode);
+		unsigned long long size = le64_to_cpu(t->cmd.p.io.size);
+		unsigned long long offset = le64_to_cpu(t->cmd.p.io.offset);
+
+		pr_debug("pohmelfs: %s: write failed: ino: %lu, isize: %llu, offset: %llu, size: %llu: %d\n",
+				pohmelfs_dump_id(pi->id.id), inode->i_ino, inode->i_size, offset, size, cmd->status);
+	}
+
+	return 0;
+}
+
+static int pohmelfs_write_command_init(struct pohmelfs_trans *t)
+{
+	struct pohmelfs_write_ctl *ctl = t->wctl;
+
+	kref_get(&ctl->refcnt);
+	return 0;
+}
+
+static void pohmelfs_write_command_destroy(struct pohmelfs_trans *t)
+{
+	struct pohmelfs_write_ctl *ctl = t->wctl;
+
+	kref_put(&ctl->refcnt, pohmelfs_write_ctl_release);
+}
+
+int pohmelfs_write_command(struct pohmelfs_inode *pi, struct pohmelfs_write_ctl *ctl, loff_t offset, size_t len)
+{
+	int err;
+	struct inode *inode = &pi->vfs_inode;
+	struct pohmelfs_io *pio;
+	uint64_t prepare_size = i_size_read(&pi->vfs_inode);
+
+	pio = kmem_cache_zalloc(pohmelfs_io_cache, GFP_NOIO);
+	if (!pio) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	pio->pi = pi;
+	pio->id = &pi->id;
+	pio->cmd = DNET_CMD_WRITE;
+	pio->offset = offset;
+	pio->size = len;
+	pio->cflags = DNET_FLAGS_NEED_ACK;
+
+	/*
+	 * We always set prepare bit, since elliptics/eblob reuses existing (previously prepared/reserved) area
+	 * But it also allows to 'miss' prepare message (for example if we sent prepare bit when node was offline)
+	 */
+	pio->ioflags = DNET_IO_FLAGS_OVERWRITE | DNET_IO_FLAGS_PLAIN_WRITE | DNET_IO_FLAGS_PREPARE;
+
+	pio->num = prepare_size;
+
+	/* commit when whole inode is written */
+	if (offset + len == prepare_size) {
+		pio->ioflags |= DNET_IO_FLAGS_COMMIT;
+	}
+
+	pio->wctl = ctl;
+	pio->priv = ctl;
+	pio->cb.complete = pohmelfs_write_command_complete;
+	pio->cb.init = pohmelfs_write_command_init;
+	pio->cb.destroy = pohmelfs_write_command_destroy;
+
+	pr_debug("pohmelfs_write_prepare_commit: %s: ino: %lu, offset: %llu, len: %zu, total size: %llu\n",
+			pohmelfs_dump_id(pi->id.id), inode->i_ino, (unsigned long long)offset, len, inode->i_size);
+
+	err = pohmelfs_send_io(pio);
+	if (err)
+		goto err_out_free;
+
+err_out_free:
+	kmem_cache_free(pohmelfs_io_cache, pio);
+err_out_exit:
+	return err;
+}
+
+int pohmelfs_metadata_inode(struct pohmelfs_inode *pi, int sync)
+{
+	struct inode *inode = &pi->vfs_inode;
+	struct pohmelfs_sb *psb = pohmelfs_sb(inode->i_sb);
+	struct pohmelfs_io *pio;
+	struct pohmelfs_wait *wait;
+	long ret;
+	int err;
+
+	wait = pohmelfs_wait_alloc(pi);
+	if (!wait) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	pio = kmem_cache_zalloc(pohmelfs_io_cache, GFP_NOIO);
+	if (!pio) {
+		err = -ENOMEM;
+		goto err_out_put;
+	}
+
+	err = pohmelfs_send_write_metadata(pi, pio, wait);
+	if (err)
+		goto err_out_free;
+
+	if (sync) {
+		ret = wait_event_interruptible_timeout(wait->wq,
+				wait->condition != 0 && atomic_read(&wait->refcnt.refcount) <= 2,
+				msecs_to_jiffies(psb->write_wait_timeout));
+		if (ret <= 0) {
+			err = ret;
+			if (ret == 0)
+				err = -ETIMEDOUT;
+			goto err_out_free;
+		}
+
+		if (wait->condition < 0) {
+			err = wait->condition;
+			goto err_out_free;
+		}
+	}
+
+err_out_free:
+	kmem_cache_free(pohmelfs_io_cache, pio);
+err_out_put:
+	pohmelfs_wait_put(wait);
+err_out_exit:
+	return err;
+}
+
+static long pohmelfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
+{
+	struct inode *inode = file->f_path.dentry->d_inode;
+	struct pohmelfs_inode *pi = pohmelfs_inode(inode);
+	struct pohmelfs_io *pio;
+	int err;
+
+	if (offset + len < i_size_read(inode)) {
+		err = 0;
+		goto err_out_exit;
+	}
+
+	pio = kmem_cache_zalloc(pohmelfs_io_cache, GFP_NOIO);
+	if (!pio) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	pio->pi = pi;
+	pio->id = &pi->id;
+	pio->cmd = DNET_CMD_WRITE;
+	pio->cflags = DNET_FLAGS_NEED_ACK;
+	pio->ioflags = DNET_IO_FLAGS_PREPARE;
+	pio->num = i_size_read(inode);
+
+	pr_debug("pohmelfs_fallocate: %s: ino: %lu, offset: %llu, len: %llu, total size: %llu\n",
+			pohmelfs_dump_id(pi->id.id), inode->i_ino,
+			(unsigned long long)offset, (unsigned long long)len, inode->i_size);
+
+	err = pohmelfs_send_io(pio);
+	if (err)
+		goto err_out_free;
+
+err_out_free:
+	kmem_cache_free(pohmelfs_io_cache, pio);
+err_out_exit:
+	return err;
+}
+
+struct pohmelfs_latest_ctl {
+	struct dnet_id			id;
+	uint64_t			offset;
+	uint64_t			size;
+};
+
+static int pohmelfs_read_latest_complete(struct pohmelfs_trans *t, struct pohmelfs_state *recv)
+{
+	struct pohmelfs_inode *pi = pohmelfs_inode(t->inode);
+	struct pohmelfs_wait *wait = t->priv;
+	struct dnet_cmd *cmd = &recv->cmd;
+	int err = cmd->status;
+
+	if (cmd->status)
+		goto err_out_exit;
+
+	if (cmd->flags & DNET_FLAGS_MORE) {
+		pr_debug("pohmelfs: %s: read-latest: complete: group: %d, attr size: %lld\n",
+				pohmelfs_dump_id(cmd->id.id), cmd->id.group_id, cmd->size - sizeof(struct dnet_attr));
+		if (cmd->size < sizeof(struct dnet_attr) + 4) {
+			err = -ENOENT;
+			goto err_out_exit;
+		}
+
+		mutex_lock(&pi->lock);
+		if (!pi->groups) {
+			pi->groups = kmalloc(cmd->size - sizeof(struct dnet_attr), GFP_NOIO);
+			if (!pi->groups) {
+				err = -ENOMEM;
+				mutex_unlock(&pi->lock);
+				goto err_out_exit;
+			}
+
+			pi->group_num = (cmd->size - sizeof(struct dnet_attr)) / sizeof(int);
+			memcpy(pi->groups, t->recv_data + sizeof(struct dnet_attr), pi->group_num * sizeof(int));
+
+			pr_debug("pohmelfs: %s: read-latest: complete: group: %d, received: %d groups\n",
+					pohmelfs_dump_id(cmd->id.id), cmd->id.group_id, pi->group_num);
+		}
+		mutex_unlock(&pi->lock);
+	}
+
+err_out_exit:
+	if (err)
+		wait->condition = err;
+	else
+		wait->condition = 1;
+	return 0;
+}
+
+static int pohmelfs_read_latest_group(struct pohmelfs_inode *pi, struct pohmelfs_latest_ctl *r, int group_id)
+{
+	struct pohmelfs_script_req req;
+
+	memset(&req, 0, sizeof(struct pohmelfs_script_req));
+
+	req.script_name = POHMELFS_READ_LATEST_GROUPS_SCRIPT;
+	req.script_namelen = sizeof(POHMELFS_READ_LATEST_GROUPS_SCRIPT) - 1;
+
+	req.obj_name = "noname";
+	req.obj_len = 5;
+
+	req.binary = r;
+	req.binary_size = sizeof(struct pohmelfs_latest_ctl);
+
+	req.id = &pi->id;
+	req.group_id = group_id;
+	req.sync = 1;
+	req.cflags = 0;
+	req.complete = pohmelfs_read_latest_complete;
+
+	return pohmelfs_send_script_request(pi, &req);
+}
+
+static int pohmelfs_read_latest(struct pohmelfs_inode *pi)
+{
+	struct pohmelfs_latest_ctl *r;
+	struct pohmelfs_sb *psb = pohmelfs_sb(pi->vfs_inode.i_sb);
+	int i, err = -ENOENT;
+
+	r = kzalloc(sizeof(struct pohmelfs_latest_ctl), GFP_NOIO);
+	if (!r) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	dnet_setup_id(&r->id, 0, pi->id.id);
+
+	for (i = 0; i < psb->group_num; ++i) {
+		r->id.group_id = psb->groups[i];
+
+		err = pohmelfs_read_latest_group(pi, r, psb->groups[i]);
+		if (err)
+			continue;
+
+		break;
+	}
+
+	kfree(r);
+
+	pr_debug("pohmelfs: %s: read-latest: %d groups\n", pohmelfs_dump_id(pi->id.id), pi->group_num);
+
+err_out_exit:
+	return err;
+}
+
+static int pohmelfs_file_open(struct inode *inode, struct file *filp)
+{
+	struct pohmelfs_inode *pi = pohmelfs_inode(inode);
+
+	if (!pi->group_num && !pi->local)
+		pohmelfs_read_latest(pi);
+
+	if (pohmelfs_need_resync(pi))
+		invalidate_mapping_pages(&inode->i_data, 0, ~0ULL);
+
+	return generic_file_open(inode, filp);
+}
+
+/*
+ * We want fsync() to work on POHMELFS.
+ */
+static int pohmelfs_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
+{
+	struct inode *inode = filp->f_mapping->host;
+	int err = filemap_write_and_wait_range(inode->i_mapping, start, end);
+	if (!err) {
+		mutex_lock(&inode->i_mutex);
+		err = sync_inode_metadata(inode, 1);
+		mutex_unlock(&inode->i_mutex);
+	}
+	pr_debug("pohmelfs: fsync: %s: start: %lld, end: %lld, nrpages: %ld, dirty: %d: %d\n",
+			pohmelfs_dump_id(pohmelfs_inode(inode)->id.id),
+			(unsigned long long)start, (unsigned long long)end,
+			inode->i_mapping->nrpages, mapping_cap_writeback_dirty(inode->i_mapping), err);
+	return err;
+}
+
+static int pohmelfs_flush(struct file *filp, fl_owner_t id)
+{
+	struct inode *inode = filp->f_mapping->host;
+	struct pohmelfs_sb *psb = pohmelfs_sb(inode->i_sb);
+	int err = 0;
+
+	if (psb->sync_on_close)
+		err = pohmelfs_fsync(filp, 0, ~0ULL, 1);
+
+	if (!err && test_bit(AS_EIO, &inode->i_mapping->flags))
+		err = -EIO;
+
+	pr_debug("pohmelfs: flush: %s: %d\n", pohmelfs_dump_id(pohmelfs_inode(inode)->id.id), err);
+	return err;
+}
+
+const struct file_operations pohmelfs_file_ops = {
+	.open		= pohmelfs_file_open,
+
+	.llseek		= generic_file_llseek,
+
+	.read		= do_sync_read,
+	.aio_read	= generic_file_aio_read,
+
+	.mmap		= generic_file_mmap,
+
+	.splice_read	= generic_file_splice_read,
+	.splice_write	= generic_file_splice_write,
+
+	.write		= do_sync_write,
+	.aio_write	= generic_file_aio_write,
+
+	.fallocate	= pohmelfs_fallocate,
+
+	.fsync		= pohmelfs_fsync,
+	.flush		= pohmelfs_flush,
+};
+
+const struct inode_operations pohmelfs_file_inode_operations = {
+};
diff --git a/fs/pohmelfs/inode.c b/fs/pohmelfs/inode.c
new file mode 100644
index 0000000..ff6c7cb
--- /dev/null
+++ b/fs/pohmelfs/inode.c
@@ -0,0 +1,1092 @@
+/*
+ * Copyright (C) 2011+ Evgeniy Polyakov <zbr@xxxxxxxxxxx>
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/cred.h>
+#include <linux/fiemap.h>
+#include <linux/fs.h>
+#include <linux/fs_struct.h>
+#include <linux/mpage.h>
+#include <linux/mount.h>
+#include <linux/mm.h>
+#include <linux/namei.h>
+#include <linux/pagevec.h>
+#include <linux/pagemap.h>
+#include <linux/random.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/writeback.h>
+
+#include "pohmelfs.h"
+
+char *pohmelfs_dump_id_len_raw(const unsigned char *id, unsigned int len, char *dst)
+{
+	unsigned int i;
+
+	if (len > SHA512_DIGEST_SIZE)
+		len = SHA512_DIGEST_SIZE;
+
+	for (i=0; i<len; ++i)
+		sprintf(&dst[2*i], "%02x", id[i]);
+	return dst;
+}
+
+#define pohmelfs_dump_len 6
+typedef struct {
+	char			id_str[pohmelfs_dump_len * 2 + 1];
+} pohmelfs_dump_t;
+static DEFINE_PER_CPU(pohmelfs_dump_t, pohmelfs_dump_per_cpu);
+
+char *pohmelfs_dump_id(const unsigned char *id)
+{
+	pohmelfs_dump_t *ptr;
+
+	ptr = &get_cpu_var(pohmelfs_dump_per_cpu);
+	pohmelfs_dump_id_len_raw(id, pohmelfs_dump_len, ptr->id_str);
+	put_cpu_var(ptr);
+
+	return ptr->id_str;
+}
+
+#define dnet_raw_id_scratch 6
+typedef struct {
+	unsigned long 			rand;
+	struct timespec			ts;
+} dnet_raw_id_scratch_t;
+static DEFINE_PER_CPU(dnet_raw_id_scratch_t, dnet_raw_id_scratch_per_cpu);
+
+static int pohmelfs_gen_id(struct pohmelfs_sb *psb, struct dnet_raw_id *id)
+{
+	dnet_raw_id_scratch_t *sc;
+	int err;
+	long rand;
+
+	get_random_bytes(&rand, sizeof(sc->rand));
+
+	sc = &get_cpu_var(dnet_raw_id_scratch_per_cpu);
+	sc->rand ^= rand;
+	sc->ts = CURRENT_TIME;
+
+	err = pohmelfs_hash(psb, sc, sizeof(dnet_raw_id_scratch_t), id);
+	put_cpu_var(sc);
+
+	return err;
+}
+
+#define UNHASHED_OBSCURE_STRING_SIZE		sizeof(" (deleted)")
+
+/*
+ * Create path from root for given inode.
+ * Path is formed as set of stuctures, containing name of the object
+ * and its inode data (mode, permissions and so on).
+ */
+static int pohmelfs_construct_path_string(struct pohmelfs_inode *pi, void *data, int len)
+{
+	struct path path;
+	struct dentry *d;
+	char *ptr;
+	int err = 0, strlen, reduce = 0;
+
+	d = d_find_alias(&pi->vfs_inode);
+	if (!d) {
+		err = -ENOENT;
+		goto err_out_exit;
+	}
+
+	spin_lock(&current->fs->lock);
+	path.mnt = mntget(current->fs->root.mnt);
+	spin_unlock(&current->fs->lock);
+
+	path.dentry = d;
+
+	if (!IS_ROOT(d) && d_unhashed(d))
+		reduce = 1;
+
+	ptr = d_path(&path, data, len);
+	if (IS_ERR(ptr)) {
+		err = PTR_ERR(ptr);
+		goto err_out_put;
+	}
+
+	if (reduce && len >= UNHASHED_OBSCURE_STRING_SIZE) {
+		char *end = data + len - UNHASHED_OBSCURE_STRING_SIZE;
+		*end = '\0';
+	}
+
+	strlen = len - (ptr - (char *)data);
+	memmove(data, ptr, strlen);
+	ptr = data;
+
+	err = strlen - 1; /* no including 0-byte */
+
+	pr_debug("%s: dname: '%s', len: %u, maxlen: %u, name: '%s', strlen: %d.\n",
+			__func__, d->d_name.name, d->d_name.len, len, ptr, strlen);
+
+err_out_put:
+	dput(d);
+	mntput(path.mnt);
+err_out_exit:
+	return err;
+}
+
+int pohmelfs_http_compat_id(struct pohmelfs_inode *pi)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(pi->vfs_inode.i_sb);
+	struct timespec ts = CURRENT_TIME;
+	int idx = ts.tv_nsec % psb->http_compat;
+	struct pohmelfs_path *p = &psb->path[idx];
+	int err;
+
+	mutex_lock(&p->lock);
+	err = pohmelfs_construct_path_string(pi, p->data, PAGE_SIZE);
+	if (err > 0) {
+		pohmelfs_hash(psb, p->data, err, &pi->id);
+	}
+	mutex_unlock(&p->lock);
+
+	return err;
+}
+
+static int pohmelfs_sb_inode_insert(struct pohmelfs_sb *psb, struct pohmelfs_inode *pi)
+{
+	struct rb_node **n = &psb->inode_root.rb_node, *parent = NULL;
+	struct pohmelfs_inode *tmp;
+	int cmp, err = 0;
+
+	spin_lock(&psb->inode_lock);
+	while (*n) {
+		parent = *n;
+
+		tmp = rb_entry(parent, struct pohmelfs_inode, node);
+
+		cmp = dnet_id_cmp_str(tmp->id.id, pi->id.id);
+		if (cmp < 0)
+			n = &parent->rb_left;
+		else if (cmp > 0)
+			n = &parent->rb_right;
+		else {
+			err = -EEXIST;
+			goto err_out_unlock;
+		}
+	}
+
+	rb_link_node(&pi->node, parent, n);
+	rb_insert_color(&pi->node, &psb->inode_root);
+
+err_out_unlock:
+	spin_unlock(&psb->inode_lock);
+
+	return err;
+}
+
+struct pohmelfs_inode *pohmelfs_sb_inode_lookup(struct pohmelfs_sb *psb, struct dnet_raw_id *id)
+{
+	struct rb_node *n = psb->inode_root.rb_node;
+	struct pohmelfs_inode *pi, *found = NULL;
+	int cmp;
+
+	spin_lock(&psb->inode_lock);
+	while (n) {
+		pi = rb_entry(n, struct pohmelfs_inode, node);
+
+		cmp = dnet_id_cmp_str(pi->id.id, id->id);
+		if (cmp < 0) {
+			n = n->rb_left;
+		} else if (cmp > 0)
+			n = n->rb_right;
+		else {
+			found = pi;
+			break;
+		}
+	}
+	if (found) {
+		if (!igrab(&found->vfs_inode))
+			found = NULL;
+	}
+	spin_unlock(&psb->inode_lock);
+
+	return found;
+}
+
+struct inode *pohmelfs_alloc_inode(struct super_block *sb)
+{
+	struct pohmelfs_inode *pi;
+
+	pi = kmem_cache_zalloc(pohmelfs_inode_cache, GFP_NOIO);
+	if (!pi)
+		goto err_out_exit;
+
+	inode_init_once(&pi->vfs_inode);
+
+	rb_init_node(&pi->node);
+	mutex_init(&pi->lock);
+
+	return &pi->vfs_inode;
+
+err_out_exit:
+	return NULL;
+}
+
+void pohmelfs_destroy_inode(struct inode *inode)
+{
+	struct pohmelfs_inode *pi = pohmelfs_inode(inode);
+
+	pr_debug("pohmelfs: %s: destroy: ino: %ld, dirty: %lx\n", pohmelfs_dump_id(pi->id.id), inode->i_ino, inode->i_state & I_DIRTY);
+
+	kfree(pi->groups);
+	kmem_cache_free(pohmelfs_inode_cache, pi);
+}
+
+int pohmelfs_hash(struct pohmelfs_sb *psb, const void *data, const size_t size, struct dnet_raw_id *id)
+{
+	struct scatterlist sg;
+	struct hash_desc desc;
+
+	sg_init_table(&sg, 1);
+	sg_set_buf(&sg, data, size);
+
+	desc.tfm = psb->hash;
+	desc.flags = 0;
+
+	return crypto_hash_digest(&desc, &sg, size, id->id);
+}
+
+struct pohmelfs_readpages_priv {
+	struct pohmelfs_wait		wait;
+	struct kref			refcnt;
+	int				page_num, page_index;
+	struct page			*pages[0];
+};
+
+static void pohmelfs_readpages_free(struct kref *kref)
+{
+	struct pohmelfs_readpages_priv *rp = container_of(kref, struct pohmelfs_readpages_priv, refcnt);
+	struct pohmelfs_inode *pi = rp->wait.pi;
+	int i;
+
+	pr_debug("pohmelfs: %s: pohmelfs_readpages_free: read: %ld/%ld, wait: %d\n",
+		pohmelfs_dump_id(pi->id.id), atomic_long_read(&rp->wait.count),
+		rp->page_num * PAGE_CACHE_SIZE, rp->wait.condition);
+
+	for (i = 0; i < rp->page_num; ++i) {
+		struct page *page = rp->pages[i];
+
+		flush_dcache_page(page);
+		SetPageUptodate(page);
+		unlock_page(page);
+		page_cache_release(page);
+	}
+
+	iput(&rp->wait.pi->vfs_inode);
+	kfree(rp);
+}
+
+static void pohmelfs_readpages_destroy(struct pohmelfs_trans *t)
+{
+	struct pohmelfs_readpages_priv *rp = t->priv;
+	struct pohmelfs_wait *wait = &rp->wait;
+
+	if (!wait->condition)
+		wait->condition = 1;
+
+	wake_up(&wait->wq);
+	kref_put(&rp->refcnt, pohmelfs_readpages_free);
+}
+
+static int pohmelfs_readpages_complete(struct pohmelfs_trans *t, struct pohmelfs_state *recv)
+{
+	struct pohmelfs_readpages_priv *rp = t->priv;
+	struct pohmelfs_wait *wait = &rp->wait;
+	struct dnet_cmd *cmd = &recv->cmd;
+
+	if (!(cmd->flags & DNET_FLAGS_MORE)) {
+		if (!wait->condition) {
+			wait->condition = cmd->status;
+			if (!wait->condition)
+				wait->condition = 1;
+			wake_up(&rp->wait.wq);
+		}
+	}
+
+	pr_debug("pohmelfs: %d:%s: pohmelfs_readpages_complete: read: %ld, wait: %d\n",
+		cmd->id.group_id, pohmelfs_dump_id(wait->pi->id.id), atomic_long_read(&wait->count), wait->condition);
+
+	return 0;
+}
+
+static int pohmelfs_readpages_init(struct pohmelfs_trans *t)
+{
+	struct pohmelfs_readpages_priv *rp = t->priv;
+
+	kref_get(&rp->refcnt);
+	return 0;
+}
+
+static int pohmelfs_readpages_recv_reply(struct pohmelfs_trans *t, struct pohmelfs_state *recv)
+{
+	struct pohmelfs_readpages_priv *rp = t->priv;
+	struct pohmelfs_wait *wait = &rp->wait;
+	struct pohmelfs_inode *pi = wait->pi;
+	unsigned int asize = sizeof(struct dnet_attr) + sizeof(struct dnet_io_attr);
+	void *data = &t->cmd.attr; /* overwrite send buffer used for attr/ioattr */
+	struct dnet_cmd *cmd = &recv->cmd;
+	struct page *page;
+	pgoff_t offset;
+	int err, size;
+
+	if (t->io_offset < asize) {
+		size = asize - t->io_offset;
+		data += t->io_offset;
+		err = pohmelfs_recv(t, recv, data, size);
+		if (err < 0)
+			goto err_out_exit;
+
+		dnet_convert_io_attr(&t->cmd.p.io);
+	}
+
+	while (t->io_offset != cmd->size) {
+		offset = (t->io_offset - asize) & (PAGE_CACHE_SIZE - 1);
+		size = PAGE_CACHE_SIZE - offset;
+		page = rp->pages[rp->page_index];
+
+		if (size > cmd->size - t->io_offset)
+			size = cmd->size - t->io_offset;
+
+		data = kmap(page);
+		err = pohmelfs_recv(t, recv, data + offset, size);
+		kunmap(page);
+
+		if (err > 0 && ((err + offset == PAGE_CACHE_SIZE) || (t->io_offset == cmd->size)))  {
+			rp->page_index++;
+		}
+
+		if (err < 0)
+			goto err_out_exit;
+
+		atomic_long_add(err, &wait->count);
+	}
+
+	err = 0;
+
+err_out_exit:
+	if ((err < 0) && (err != -ENOENT) && (err != -EAGAIN))
+		pr_err("pohmelfs: %d:%s: pohmelfs_readpages_recv_data: offset: %lld, data size: %llu, err: %d\n",
+			cmd->id.group_id, pohmelfs_dump_id(pi->id.id), t->io_offset - asize + t->cmd.p.io.offset,
+			(unsigned long long)cmd->size - asize, err);
+
+	return err;
+}
+
+static int pohmelfs_readpages_group(struct pohmelfs_inode *pi, struct pohmelfs_readpages_priv *rp, int group_id)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(pi->vfs_inode.i_sb);
+	struct pohmelfs_wait *wait = &rp->wait;
+	struct pohmelfs_io *io;
+	long ret;
+	int err;
+
+	io = kmem_cache_zalloc(pohmelfs_io_cache, GFP_NOIO);
+	if (!io) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	io->pi = pi;
+	io->id = &pi->id;
+	io->cmd = DNET_CMD_READ;
+	/*
+	 * We send read command with lock, so its will be picked by the same threads as process
+	 * bulk write commands leaving nonblocking threads free for metadata commands like
+	 * directory reading, lookup and so on
+	 */
+	//io->cflags = DNET_FLAGS_NEED_ACK | DNET_FLAGS_NOLOCK;
+	io->cflags = DNET_FLAGS_NEED_ACK;
+	io->offset = page_offset(rp->pages[0]);
+	io->size = rp->page_num * PAGE_CACHE_SIZE;
+	if (psb->no_read_csum)
+		io->ioflags = DNET_IO_FLAGS_NOCSUM;
+	io->cb.init = pohmelfs_readpages_init;
+	io->cb.complete = pohmelfs_readpages_complete;
+	io->cb.destroy = pohmelfs_readpages_destroy;
+	io->cb.recv_reply = pohmelfs_readpages_recv_reply;
+	io->priv = rp;
+
+	err = pohmelfs_send_io_group(io, group_id);
+	if (err)
+		goto err_out_free;
+
+	ret = wait_event_interruptible_timeout(wait->wq, wait->condition != 0, msecs_to_jiffies(psb->read_wait_timeout));
+	if (ret <= 0) {
+		err = ret;
+		if (ret == 0)
+			err = -ETIMEDOUT;
+		goto err_out_free;
+	}
+
+	if (wait->condition < 0) {
+		err = wait->condition;
+		goto err_out_free;
+	}
+
+	err = atomic_long_read(&wait->count);
+
+err_out_free:
+	kmem_cache_free(pohmelfs_io_cache, io);
+err_out_exit:
+	return err;
+}
+
+static int pohmelfs_readpages_groups(struct pohmelfs_inode *pi, struct pohmelfs_readpages_priv *rp,
+		int *groups, int group_num)
+{
+	int err = -ENOENT;
+	int i;
+
+	for (i = 0; i < group_num; ++i) {
+		err = pohmelfs_readpages_group(pi, rp, groups[i]);
+		if (err < 0)
+			continue;
+
+		break;
+	}
+
+	pi->update = get_seconds();
+	return err;
+}
+
+static struct pohmelfs_readpages_priv *pohmelfs_readpages_alloc(struct pohmelfs_inode *pi, int page_num)
+{
+	struct pohmelfs_readpages_priv *rp;
+	int err;
+
+	rp = kzalloc(sizeof(struct pohmelfs_readpages_priv) + page_num * sizeof(struct page *), GFP_NOIO);
+	if (!rp) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	err = pohmelfs_wait_init(&rp->wait, pi);
+	if (err)
+		goto err_out_free;
+
+	rp->page_num = page_num;
+	kref_init(&rp->refcnt);
+	return rp;
+
+err_out_free:
+	kfree(rp);
+err_out_exit:
+	return ERR_PTR(err);
+}
+
+static int pohmelfs_readpages_send(struct pohmelfs_inode *pi, struct pohmelfs_readpages_priv *rp)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(pi->vfs_inode.i_sb);
+	int err;
+
+	if (pi->group_num) {
+		err = pohmelfs_readpages_groups(pi, rp, pi->groups, pi->group_num);
+	} else {
+		err = pohmelfs_readpages_groups(pi, rp, psb->groups, psb->group_num);
+	}
+
+	return err;
+}
+
+static int pohmelfs_readpages_send_list(struct address_space *mapping, struct list_head *page_list, int num)
+{
+	struct inode *inode = mapping->host;
+	struct pohmelfs_inode *pi = pohmelfs_inode(inode);
+	int err = 0, i;
+	struct pohmelfs_readpages_priv *rp;
+	struct page *tmp, *page;
+
+	if (list_empty(page_list))
+		goto err_out_exit;
+
+	rp = pohmelfs_readpages_alloc(pi, num);
+	if (IS_ERR(rp)) {
+		err = PTR_ERR(rp);
+		goto err_out_exit;
+	}
+
+	i = 0;
+	list_for_each_entry_safe(page, tmp, page_list, lru) {
+		list_del(&page->lru);
+
+		if (add_to_page_cache_lru(page, mapping, page->index, GFP_KERNEL)) {
+			/* Failed - free current page, optionally send already grabbed and free others */
+			page_cache_release(page);
+			break;
+		}
+
+		rp->pages[i] = page;
+		i++;
+	}
+
+	if (i > 0) {
+		rp->page_num = i;
+		err = pohmelfs_readpages_send(pi, rp);
+
+		pr_debug("pohmelfs: %s: readpages: ino: %lu, offset: %lu, pages: %u/%u: %d\n",
+				pohmelfs_dump_id(pi->id.id), inode->i_ino, (long)page_offset(rp->pages[0]), rp->page_num, num, err);
+	}
+
+	kref_put(&rp->refcnt, pohmelfs_readpages_free);
+
+	/* Cleanup pages which were not added into page cache */
+	list_for_each_entry_safe(page, tmp, page_list, lru) {
+		list_del(&page->lru);
+		page_cache_release(page);
+	}
+
+err_out_exit:
+	return err;
+}
+
+static int pohmelfs_readpages(struct file *filp, struct address_space *mapping,
+			struct list_head *page_list, unsigned nr_pages)
+{
+	struct page *tmp, *page;
+	pgoff_t idx;
+	LIST_HEAD(head);
+	int err = 0, i = 0;
+
+	while (!list_empty(page_list)) {
+		page = list_entry(page_list->prev, struct page, lru);
+		idx = page->index;
+		i = 0;
+
+		INIT_LIST_HEAD(&head);
+
+		list_for_each_entry_safe_reverse(page, tmp, page_list, lru) {
+			if (idx != page->index) {
+				struct pohmelfs_inode *pi = pohmelfs_inode(mapping->host);
+				pr_debug("pohmelfs: %s: readpage index mismatch: want: %ld, page-index: %ld, total: %d\n",
+						pohmelfs_dump_id(pi->id.id), (long)idx, (long)page->index, nr_pages);
+				break;
+			}
+
+			list_move_tail(&page->lru, &head);
+			i++;
+			idx++;
+		}
+
+		err = pohmelfs_readpages_send_list(mapping, &head, i);
+	}
+	if (err >= 0)
+		err = 0;
+
+	return err;
+}
+
+static int pohmelfs_readpage(struct file *file, struct page *page)
+{
+	struct inode *inode = page->mapping->host;
+	struct pohmelfs_inode *pi = pohmelfs_inode(inode);
+	struct pohmelfs_readpages_priv *rp;
+	int err;
+
+	if (inode->i_size <= page->index << PAGE_CACHE_SHIFT) {
+		SetPageUptodate(page);
+		unlock_page(page);
+		return 0;
+	}
+
+	rp = pohmelfs_readpages_alloc(pi, 1);
+	if (IS_ERR(rp)) {
+		err = PTR_ERR(rp);
+		goto err_out_exit;
+	}
+
+	rp->pages[0] = page;
+	page_cache_get(page);
+
+	err = pohmelfs_readpages_send(pi, rp);
+	if (err >= 0)
+		err = 0;
+
+	kref_put(&rp->refcnt, pohmelfs_readpages_free);
+err_out_exit:
+	if (err < 0)
+		pr_err("pohmelfs: %s: readpage: ino: %lu, offset: %lu, uptodate: %d, err: %d\n",
+			pohmelfs_dump_id(pi->id.id), inode->i_ino, (long)page_offset(page),
+			PageUptodate(page), err);
+
+	return err;
+}
+
+void pohmelfs_write_ctl_release(struct kref *kref)
+{
+	struct pohmelfs_write_ctl *ctl = container_of(kref, struct pohmelfs_write_ctl, refcnt);
+	struct address_space *mapping = ctl->pvec.pages[0]->mapping;
+	struct inode *inode = mapping->host;
+	struct pohmelfs_sb *psb = pohmelfs_sb(inode->i_sb);
+	int bad_write = atomic_read(&ctl->good_writes) < psb->group_num / 2 + 1;
+	struct page *page;
+	unsigned int i;
+
+	if (psb->successful_write_count && (atomic_read(&ctl->good_writes) >= psb->successful_write_count))
+		bad_write = 0;
+
+	if (bad_write) {
+		struct pohmelfs_inode *pi = pohmelfs_inode(inode);
+		unsigned long long offset = page_offset(ctl->pvec.pages[0]);
+
+		pr_debug("pohmelfs: %s: bad write: ino: %lu, isize: %llu, offset: %llu: writes: %d/%d\n",
+				pohmelfs_dump_id(pi->id.id),
+				inode->i_ino, inode->i_size, offset,
+				atomic_read(&ctl->good_writes), psb->group_num);
+		mapping_set_error(mapping, -EIO);
+	}
+
+	for (i = 0; i < pagevec_count(&ctl->pvec); ++i) {
+		page = ctl->pvec.pages[i];
+
+		if (PageLocked(page)) {
+			end_page_writeback(page);
+
+			if (bad_write) {
+				SetPageError(page);
+				ClearPageUptodate(page);
+				/*
+				 * Do not reschedule failed write page again
+				 * This may explode systems with large caches
+				 * when there is no connection to elliptics cluster
+				 */
+				//set_page_dirty(page);
+			}
+			unlock_page(page);
+		}
+	}
+
+	pagevec_release(&ctl->pvec);
+	kmem_cache_free(pohmelfs_write_cache, ctl);
+}
+
+static int pohmelfs_writepages_chunk(struct pohmelfs_inode *pi, struct pohmelfs_write_ctl *ctl,
+		struct writeback_control *wbc, struct address_space *mapping)
+{
+	struct inode *inode = &pi->vfs_inode;
+	uint64_t offset, size;
+	unsigned i;
+	int err = 0, good = 0;
+
+	offset = page_offset(ctl->pvec.pages[0]);
+
+	size = 0;
+	/* we will lookup them again when doing actual send */
+	for (i = 0; i< pagevec_count(&ctl->pvec); ++i) {
+		struct page *page = ctl->pvec.pages[i];
+
+		lock_page(page);
+#if 1
+		if (unlikely(page->mapping != mapping)) {
+continue_unlock:
+			unlock_page(page);
+			continue;
+		}
+
+		if (wbc->sync_mode != WB_SYNC_NONE)
+			wait_on_page_writeback(page);
+		if (PageWriteback(page)) {
+			unlock_page(page);
+			break;
+		}
+
+		if (!PageDirty(page))
+			goto continue_unlock;
+
+		if (!clear_page_dirty_for_io(page))
+			goto continue_unlock;
+#else
+		clear_page_dirty_for_io(page);
+#endif
+
+		set_page_writeback(page);
+
+		good++;
+		size += PAGE_CACHE_SIZE;
+		wbc->nr_to_write--;
+	}
+
+	if (good != 0) {
+		size = pagevec_count(&ctl->pvec) * PAGE_CACHE_SIZE;
+		if (offset + size > inode->i_size)
+			size = inode->i_size - offset;
+
+		err = pohmelfs_write_command(pi, ctl, offset, size);
+		if (err)
+			goto err_out_exit;
+	}
+
+err_out_exit:
+	kref_put(&ctl->refcnt, pohmelfs_write_ctl_release);
+	return err;
+}
+
+static int pohmelfs_writepages_send(struct address_space *mapping, struct writeback_control *wbc, struct pagevec *pvec, int start, int end)
+{
+	struct inode *inode = mapping->host;
+	struct pohmelfs_inode *pi = pohmelfs_inode(inode);
+	struct pohmelfs_write_ctl *ctl;
+	int err, i;
+
+	ctl = kmem_cache_zalloc(pohmelfs_write_cache, GFP_NOIO);
+	if (!ctl) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	kref_init(&ctl->refcnt);
+	atomic_set(&ctl->good_writes, 0);
+
+	for (i = start; i < end; ++i)
+		pagevec_add(&ctl->pvec, pvec->pages[i]);
+
+	err = pohmelfs_writepages_chunk(pi, ctl, wbc, mapping);
+	if (err)
+		goto err_out_exit;
+
+err_out_exit:
+	return err;
+}
+
+static int pohmelfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
+{
+	struct inode *inode = mapping->host;
+	struct pohmelfs_inode *pi = pohmelfs_inode(inode);
+	pgoff_t index, start, end /* inclusive */, idx;
+	int done = 0;
+	int range_whole = 0;
+	int should_loop = 1;
+	int nr_pages, err = 0, i, start_idx;
+	struct pagevec pvec;
+	int written = 0;
+
+	index = wbc->range_start >> PAGE_CACHE_SHIFT;
+	end = wbc->range_end >> PAGE_CACHE_SHIFT;
+
+	pr_debug("pohmelfs: %s: writepages: ino: %ld, nr: %ld, index: %llu, end: %llu, total_size: %lu, sync: %d\n",
+			pohmelfs_dump_id(pohmelfs_inode(inode)->id.id), inode->i_ino,
+			wbc->nr_to_write, wbc->range_start, wbc->range_end, (unsigned long)inode->i_size, wbc->sync_mode);
+
+	if (wbc->range_cyclic) {
+		start = mapping->writeback_index; /* Start from prev offset */
+		end = -1;
+	} else {
+		start = wbc->range_start >> PAGE_CACHE_SHIFT;
+		end = wbc->range_end >> PAGE_CACHE_SHIFT;
+		if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
+			range_whole = 1;
+		should_loop = 0;
+	}
+	index = start;
+
+retry:
+	while (!done && index <= end) {
+		nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, PAGECACHE_TAG_DIRTY,
+			      min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
+		if (!nr_pages) {
+			err = 0;
+			break;
+		}
+
+		idx = pvec.pages[0]->index;
+		for (start_idx = 0, i = 0; i< nr_pages; ++i) {
+			struct page *page = pvec.pages[i];
+
+			/* non-contiguous pages detected */
+			if (idx != page->index) {
+				err = pohmelfs_writepages_send(mapping, wbc, &pvec, start_idx, i);
+				if (err)
+					goto err_out_exit;
+				start_idx = i;
+			}
+
+			idx++;
+		}
+
+		err = pohmelfs_writepages_send(mapping, wbc, &pvec, start_idx, nr_pages);
+		if (err)
+			goto err_out_exit;
+
+		if (wbc->nr_to_write <= 0)
+			done = 1;
+
+		written += nr_pages;
+	}
+
+	if (should_loop && !done) {
+		/* more to do; loop back to beginning of file */
+		should_loop = 0;
+		index = 0;
+		goto retry;
+	}
+
+	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
+		mapping->writeback_index = index;
+
+	if (written) {
+		err = pohmelfs_metadata_inode(pi, wbc->sync_mode != WB_SYNC_NONE);
+		if (err)
+			goto err_out_exit;
+	}
+
+
+	if (test_and_clear_bit(AS_EIO, &mapping->flags))
+		err = -EIO;
+err_out_exit:
+	pr_debug("pohmelfs: %s: metadata write complete: %d\n", pohmelfs_dump_id(pi->id.id), err);
+	return err;
+}
+
+static const struct address_space_operations pohmelfs_aops = {
+	.write_begin		= simple_write_begin,
+	.write_end		= simple_write_end,
+	.writepages		= pohmelfs_writepages,
+	.readpage		= pohmelfs_readpage,
+	.readpages		= pohmelfs_readpages,
+	.set_page_dirty 	= __set_page_dirty_nobuffers,
+};
+
+void pohmelfs_convert_inode_info(struct pohmelfs_inode_info *info)
+{
+	info->ino = cpu_to_le64(info->ino);
+	info->mode = cpu_to_le64(info->mode);
+	info->nlink = cpu_to_le64(info->nlink);
+	info->uid = cpu_to_le32(info->uid);
+	info->gid = cpu_to_le32(info->gid);
+	info->namelen = cpu_to_le32(info->namelen);
+	info->blocks = cpu_to_le64(info->blocks);
+	info->rdev = cpu_to_le64(info->rdev);
+	info->size = cpu_to_le64(info->size);
+	info->version = cpu_to_le64(info->version);
+	info->blocksize = cpu_to_le64(info->blocksize);
+	info->flags = cpu_to_le64(info->flags);
+
+	dnet_convert_time(&info->ctime);
+	dnet_convert_time(&info->mtime);
+	dnet_convert_time(&info->atime);
+}
+
+void pohmelfs_fill_inode_info(struct inode *inode, struct pohmelfs_inode_info *info)
+{
+	struct pohmelfs_inode *pi = pohmelfs_inode(inode);
+
+	memcpy(info->id.id, pi->id.id, DNET_ID_SIZE);
+
+	info->ino = inode->i_ino;
+	info->mode = inode->i_mode;
+	info->nlink = inode->i_nlink;
+	info->uid = inode->i_uid;
+	info->gid = inode->i_gid;
+	info->blocks = inode->i_blocks;
+	info->rdev = inode->i_rdev;
+	info->size = inode->i_size;
+	info->version = inode->i_version;
+	info->blocksize = 1 << inode->i_blkbits;
+
+	info->ctime.tsec = inode->i_ctime.tv_sec;
+	info->ctime.tnsec = inode->i_ctime.tv_nsec;
+
+	info->mtime.tsec = inode->i_mtime.tv_sec;
+	info->mtime.tnsec = inode->i_mtime.tv_nsec;
+
+	info->atime.tsec = inode->i_atime.tv_sec;
+	info->atime.tnsec = inode->i_atime.tv_nsec;
+
+	info->flags = 0;
+}
+
+void pohmelfs_fill_inode(struct inode *inode, struct pohmelfs_inode_info *info)
+{
+	pr_debug("pohmelfs: %s: ino: %lu inode is regular: %d, dir: %d, link: %d, mode: %o, "
+			"namelen: %u, size: %llu, state: %lx, mtime: %llu.%llu/%lu.%lu\n",
+			pohmelfs_dump_id(info->id.id), inode->i_ino,
+			S_ISREG(inode->i_mode), S_ISDIR(inode->i_mode),
+			S_ISLNK(inode->i_mode), inode->i_mode, info->namelen, inode->i_size, inode->i_state,
+			(unsigned long long)info->mtime.tsec, (unsigned long long)info->mtime.tnsec,
+			inode->i_mtime.tv_sec, inode->i_mtime.tv_nsec);
+
+	if (info->mtime.tsec < inode->i_mtime.tv_sec)
+		return;
+	if ((info->mtime.tsec == inode->i_mtime.tv_sec) &&
+			(info->mtime.tnsec < inode->i_mtime.tv_nsec))
+		return;
+
+	pohmelfs_inode(inode)->id = info->id;
+
+	inode->i_mode = info->mode;
+	set_nlink(inode, info->nlink);
+	inode->i_uid = info->uid;
+	inode->i_gid = info->gid;
+	inode->i_blocks = info->blocks;
+	inode->i_rdev = info->rdev;
+	inode->i_size = info->size;
+	inode->i_version = info->version;
+	inode->i_blkbits = ffs(info->blocksize);
+
+	inode->i_mtime = pohmelfs_date(&info->mtime);
+	inode->i_atime = pohmelfs_date(&info->atime);
+	inode->i_ctime = pohmelfs_date(&info->ctime);
+}
+
+static void pohmelfs_inode_info_current(struct pohmelfs_sb *psb, struct pohmelfs_inode_info *info)
+{
+	struct timespec ts = CURRENT_TIME;
+	struct dnet_time dtime;
+
+	info->nlink = S_ISDIR(info->mode) ? 2 : 1;
+	info->uid = current_fsuid();
+	info->gid = current_fsgid();
+	info->size = 0;
+	info->blocksize = PAGE_SIZE;
+	info->blocks = 0;
+	info->rdev = 0;
+	info->version = 0;
+
+	dtime.tsec = ts.tv_sec;
+	dtime.tnsec = ts.tv_nsec;
+
+	info->ctime = dtime;
+	info->mtime = dtime;
+	info->atime = dtime;
+
+	pohmelfs_gen_id(psb, &info->id);
+}
+
+const struct inode_operations pohmelfs_special_inode_operations = {
+	.setattr			= simple_setattr,
+};
+
+struct pohmelfs_inode *pohmelfs_existing_inode(struct pohmelfs_sb *psb, struct pohmelfs_inode_info *info)
+{
+	struct pohmelfs_inode *pi;
+	struct inode *inode;
+	int err;
+
+	inode = iget_locked(psb->sb, atomic_long_inc_return(&psb->ino));
+	if (!inode) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	pi = pohmelfs_inode(inode);
+
+	if (inode->i_state & I_NEW) {
+		pohmelfs_fill_inode(inode, info);
+		/*
+		 * i_mapping is a pointer to i_data during inode initialization.
+		 */
+		inode->i_data.a_ops = &pohmelfs_aops;
+
+		if (S_ISREG(inode->i_mode)) {
+			inode->i_fop = &pohmelfs_file_ops;
+			inode->i_op = &pohmelfs_file_inode_operations;
+		} else if (S_ISDIR(inode->i_mode)) {
+			inode->i_fop = &pohmelfs_dir_fops;
+			inode->i_op = &pohmelfs_dir_inode_operations;
+		} else if (S_ISLNK(inode->i_mode)) {
+			inode->i_op = &pohmelfs_symlink_inode_operations;
+			inode->i_mapping->a_ops = &pohmelfs_aops;
+		} else {
+			inode->i_op = &pohmelfs_special_inode_operations;
+		}
+
+		err = pohmelfs_sb_inode_insert(psb, pi);
+		if (err)
+			goto err_out_put;
+
+		unlock_new_inode(inode);
+	}
+
+	return pi;
+
+err_out_put:
+	unlock_new_inode(inode);
+	iput(inode);
+err_out_exit:
+	return ERR_PTR(err);
+}
+
+struct pohmelfs_inode *pohmelfs_new_inode(struct pohmelfs_sb *psb, int mode)
+{
+	struct pohmelfs_inode *pi;
+	struct pohmelfs_inode_info *info;
+	int err;
+
+	info = kmem_cache_zalloc(pohmelfs_inode_info_cache, GFP_NOIO);
+	if (!info) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	info->mode = mode;
+
+	pohmelfs_inode_info_current(psb, info);
+
+	pi = pohmelfs_existing_inode(psb, info);
+	if (IS_ERR(pi)) {
+		err = PTR_ERR(pi);
+		goto err_out_free;
+	}
+
+	kmem_cache_free(pohmelfs_inode_info_cache, info);
+	return pi;
+
+err_out_free:
+	kmem_cache_free(pohmelfs_inode_info_cache, info);
+err_out_exit:
+	return ERR_PTR(err);
+}
+
+int pohmelfs_wait_init(struct pohmelfs_wait *wait, struct pohmelfs_inode *pi)
+{
+	if (!igrab(&pi->vfs_inode))
+		return -EINVAL;
+
+	wait->pi = pi;
+
+	atomic_long_set(&wait->count, 0);
+	init_waitqueue_head(&wait->wq);
+	kref_init(&wait->refcnt);
+
+	return 0;
+}
+
+struct pohmelfs_wait *pohmelfs_wait_alloc(struct pohmelfs_inode *pi)
+{
+	struct pohmelfs_wait *wait;
+
+	wait = kmem_cache_zalloc(pohmelfs_wait_cache, GFP_NOIO);
+	if (!wait) {
+		goto err_out_exit;
+	}
+
+	if (pohmelfs_wait_init(wait, pi))
+		goto err_out_free;
+
+	return wait;
+
+err_out_free:
+	kmem_cache_free(pohmelfs_wait_cache, wait);
+err_out_exit:
+	return NULL;
+}
+
+static void pohmelfs_wait_free(struct kref *kref)
+{
+	struct pohmelfs_wait *wait = container_of(kref, struct pohmelfs_wait, refcnt);
+	struct inode *inode = &wait->pi->vfs_inode;
+
+	iput(inode);
+	kmem_cache_free(pohmelfs_wait_cache, wait);
+}
+
+void pohmelfs_wait_put(struct pohmelfs_wait *wait)
+{
+	kref_put(&wait->refcnt, pohmelfs_wait_free);
+}
diff --git a/fs/pohmelfs/net.c b/fs/pohmelfs/net.c
new file mode 100644
index 0000000..f53203c
--- /dev/null
+++ b/fs/pohmelfs/net.c
@@ -0,0 +1,697 @@
+/*
+ * Copyright (C) 2011+ Evgeniy Polyakov <zbr@xxxxxxxxxxx>
+ */
+
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <linux/net.h>
+
+#include <net/sock.h>
+#include <net/tcp.h>
+
+#include "pohmelfs.h"
+
+void *pohmelfs_scratch_buf;
+int pohmelfs_scratch_buf_size = 4096;
+
+void pohmelfs_print_addr(struct sockaddr_storage *addr, const char *fmt, ...)
+{
+	struct sockaddr *sa = (struct sockaddr *)addr;
+	va_list args;
+	char *ptr;
+
+	va_start(args, fmt);
+	ptr = kvasprintf(GFP_NOIO, fmt, args);
+	if (!ptr)
+		goto err_out_exit;
+
+	if (sa->sa_family == AF_INET) {
+		struct sockaddr_in *sin = (struct sockaddr_in *)addr;
+		pr_info("pohmelfs: %pI4:%d: %s", &sin->sin_addr.s_addr, ntohs(sin->sin_port), ptr);
+	} else if (sa->sa_family == AF_INET6) {
+		struct sockaddr_in6 *sin = (struct sockaddr_in6 *)addr;
+		pr_info("pohmelfs: %pI6:%d: %s", &sin->sin6_addr, ntohs(sin->sin6_port), ptr);
+	}
+
+	kfree(ptr);
+err_out_exit:
+	va_end(args);
+}
+
+/*
+ * Basic network sending/receiving functions.
+ * Blocked mode is used.
+ */
+int pohmelfs_data_recv(struct pohmelfs_state *st, void *buf, u64 size, unsigned int flags)
+{
+	struct msghdr msg;
+	struct kvec iov;
+	int err;
+
+	BUG_ON(!size);
+
+	iov.iov_base = buf;
+	iov.iov_len = size;
+
+	msg.msg_iov = (struct iovec *)&iov;
+	msg.msg_iovlen = 1;
+	msg.msg_name = NULL;
+	msg.msg_namelen = 0;
+	msg.msg_control = NULL;
+	msg.msg_controllen = 0;
+	msg.msg_flags = flags;
+
+	err = kernel_recvmsg(st->sock, &msg, &iov, 1, iov.iov_len, msg.msg_flags);
+	if (err < 0)
+		goto err_out_exit;
+
+err_out_exit:
+	return err;
+}
+
+int pohmelfs_recv(struct pohmelfs_trans *t, struct pohmelfs_state *recv, void *data, int size)
+{
+	int err;
+
+	err = pohmelfs_data_recv(recv, data, size, MSG_DONTWAIT);
+	if (err < 0)
+		return err;
+
+	t->io_offset += err;
+	return err;
+}
+
+static int pohmelfs_data_send(struct pohmelfs_trans *t)
+{
+	struct msghdr msg;
+	struct iovec io;
+	int err;
+
+	msg.msg_name = NULL;
+	msg.msg_namelen = 0;
+	msg.msg_control = NULL;
+	msg.msg_controllen = 0;
+	msg.msg_flags = MSG_DONTWAIT;
+
+	msg.msg_iov = &io;
+	msg.msg_iovlen = 1;
+
+
+	if (t->io_offset < t->header_size) {
+		io.iov_base = (void *)(&t->cmd) + t->io_offset;
+		io.iov_len = t->header_size - t->io_offset;
+
+		err = kernel_sendmsg(t->st->sock, &msg, (struct kvec *)msg.msg_iov, 1, io.iov_len);
+		if (err < 0) {
+			if (err == 0)
+				err = -ECONNRESET;
+			goto err_out_exit;
+		}
+
+		t->io_offset += err;
+	}
+
+	if ((t->io_offset >= t->header_size) && t->data) {
+		size_t sent_size = t->io_offset - t->header_size;
+		io.iov_base = t->data + sent_size;
+		io.iov_len = t->data_size - sent_size;
+
+		err = kernel_sendmsg(t->st->sock, &msg, (struct kvec *)msg.msg_iov, 1, io.iov_len);
+		if (err < 0) {
+			if (err == 0)
+				err = -ECONNRESET;
+			goto err_out_exit;
+		}
+
+		t->io_offset += err;
+	}
+
+
+	err = 0;
+
+err_out_exit:
+	return err;
+}
+
+static int pohmelfs_page_send(struct pohmelfs_trans *t)
+{
+	struct pohmelfs_write_ctl *ctl = t->wctl;
+	struct msghdr msg;
+	struct iovec io;
+	unsigned i;
+	int err = -EINVAL;
+
+	if (t->io_offset < t->header_size) {
+		io.iov_base = (void *)(&t->cmd) + t->io_offset;
+		io.iov_len = t->header_size - t->io_offset;
+
+		msg.msg_name = NULL;
+		msg.msg_namelen = 0;
+		msg.msg_control = NULL;
+		msg.msg_controllen = 0;
+		msg.msg_flags = MSG_DONTWAIT;
+
+		msg.msg_iov = &io;
+		msg.msg_iovlen = 1;
+
+		err = kernel_sendmsg(t->st->sock, &msg, (struct kvec *)msg.msg_iov, 1, io.iov_len);
+		if (err < 0) {
+			if (err == 0)
+				err = -ECONNRESET;
+			goto err_out_exit;
+		}
+
+		t->io_offset += err;
+	}
+
+	if (t->io_offset >= t->header_size) {
+		size_t skip_offset = 0;
+		size_t size = le64_to_cpu(t->cmd.cmd.size) + sizeof(struct dnet_cmd) - t->io_offset;
+		size_t current_io_offset = t->io_offset - t->header_size;
+
+		for (i = 0; i < pagevec_count(&ctl->pvec); ++i) {
+			struct page *page = ctl->pvec.pages[i];
+			size_t sz = PAGE_CACHE_SIZE;
+
+			if (sz > size)
+				sz = size;
+
+			if (current_io_offset > skip_offset + sz) {
+				skip_offset += sz;
+				continue;
+			}
+
+			sz -= current_io_offset - skip_offset;
+
+			err = kernel_sendpage(t->st->sock, page, current_io_offset - skip_offset, sz, MSG_DONTWAIT);
+
+			pr_debug("pohmelfs: %s: %d/%d: total-size: %llu, io-offset: %llu, rest-size: %zd, current-io: %zd, "
+					"skip-offset: %zd, sz: %zu: %d\n",
+					pohmelfs_dump_id(pohmelfs_inode(t->inode)->id.id), i, pagevec_count(&ctl->pvec),
+					(unsigned long long)le64_to_cpu(t->cmd.cmd.size) + sizeof(struct dnet_cmd),
+					t->io_offset, size, current_io_offset, skip_offset, sz, err);
+
+			if (err <= 0) {
+				if (err == 0)
+					err = -ECONNRESET;
+				goto err_out_exit;
+			}
+
+			current_io_offset += err;
+			skip_offset = current_io_offset;
+			size -= err;
+			t->io_offset += err;
+
+			err = 0;
+		}
+	}
+
+err_out_exit:
+	return err;
+}
+
+/*
+ * Polling machinery.
+ */
+
+struct pohmelfs_poll_helper {
+	poll_table 		pt;
+	struct pohmelfs_state	*st;
+};
+
+static int pohmelfs_queue_wake(wait_queue_t *wait, unsigned mode, int sync, void *key)
+{
+	struct pohmelfs_state *st = container_of(wait, struct pohmelfs_state, wait);
+
+	if (!st->conn->need_exit)
+		queue_work(st->conn->wq, &st->io_work);
+	return 0;
+}
+
+static void pohmelfs_queue_func(struct file *file, wait_queue_head_t *whead, poll_table *pt)
+{
+	struct pohmelfs_state *st = container_of(pt, struct pohmelfs_poll_helper, pt)->st;
+
+	st->whead = whead;
+
+	init_waitqueue_func_entry(&st->wait, pohmelfs_queue_wake);
+	add_wait_queue(whead, &st->wait);
+}
+
+static void pohmelfs_poll_exit(struct pohmelfs_state *st)
+{
+	if (st->whead) {
+		remove_wait_queue(st->whead, &st->wait);
+		st->whead = NULL;
+	}
+}
+
+static int pohmelfs_poll_init(struct pohmelfs_state *st)
+{
+	struct pohmelfs_poll_helper ph;
+
+	ph.st = st;
+	init_poll_funcptr(&ph.pt, &pohmelfs_queue_func);
+
+	st->sock->ops->poll(NULL, st->sock, &ph.pt);
+	return 0;
+}
+
+static int pohmelfs_revents(struct pohmelfs_state *st, unsigned mask)
+{
+	unsigned revents;
+
+	revents = st->sock->ops->poll(NULL, st->sock, NULL);
+	if (revents & mask)
+		return 0;
+
+	if (revents & (POLLERR | POLLHUP | POLLNVAL | POLLRDHUP | POLLREMOVE)) {
+		pohmelfs_print_addr(&st->sa, "error revents: %x\n", revents);
+		return -ECONNRESET;
+	}
+
+	return -EAGAIN;
+}
+
+static int pohmelfs_state_send(struct pohmelfs_state *st)
+{
+	struct pohmelfs_trans *t = NULL;
+	int trans_put = 0;
+	size_t size;
+	int err = -EAGAIN;
+
+	mutex_lock(&st->trans_lock);
+	if (!list_empty(&st->trans_list))
+		t = list_first_entry(&st->trans_list, struct pohmelfs_trans, trans_entry);
+	mutex_unlock(&st->trans_lock);
+
+	if (!t)
+		goto err_out_exit;
+
+	err = pohmelfs_revents(st, POLLOUT);
+	if (err)
+		goto err_out_exit;
+
+	size = le64_to_cpu(t->cmd.cmd.size) + sizeof(struct dnet_cmd);
+	pr_debug("pohmelfs: %s: starting sending: %llu/%zd\n", pohmelfs_dump_id(pohmelfs_inode(t->inode)->id.id), t->io_offset, size);
+
+	if (t->wctl)
+		err = pohmelfs_page_send(t);
+	else
+		err = pohmelfs_data_send(t);
+
+	pr_debug("pohmelfs: %s: sent: %llu/%zd: %d\n", pohmelfs_dump_id(pohmelfs_inode(t->inode)->id.id), t->io_offset, size, err);
+	if (!err && (t->io_offset == size)) {
+		mutex_lock(&st->trans_lock);
+			list_del_init(&t->trans_entry);
+			err = pohmelfs_trans_insert_tree(st, t);
+			if (err)
+				trans_put = 1;
+			t->io_offset = 0;
+		mutex_unlock(&st->trans_lock);
+	}
+
+	BUG_ON(t->io_offset > size);
+
+	if (trans_put)
+		pohmelfs_trans_put(t);
+
+	if ((err < 0) && (err != -EAGAIN))
+		goto err_out_exit;
+
+err_out_exit:
+	return err;
+}
+
+static void pohmelfs_suck_scratch(struct pohmelfs_state *st)
+{
+	struct dnet_cmd *cmd = &st->cmd;
+	int err = 0;
+
+	pr_debug("pohmelfs_suck_scratch: %llu\n", (unsigned long long)cmd->size);
+
+	while (cmd->size) {
+		int sz = pohmelfs_scratch_buf_size;
+
+		if (cmd->size < sz)
+			sz = cmd->size;
+
+		err = pohmelfs_data_recv(st, pohmelfs_scratch_buf, sz, MSG_WAITALL);
+		if (err < 0) {
+			pohmelfs_print_addr(&st->sa, "recv-scratch err: %d\n", err);
+			goto err_out_exit;
+		}
+
+		cmd->size -= err;
+	}
+
+err_out_exit:
+	st->cmd_read = 1;
+}
+
+static int pohmelfs_state_recv(struct pohmelfs_state *st)
+{
+	struct dnet_cmd *cmd = &st->cmd;
+	struct pohmelfs_trans *t;
+	unsigned long long trans;
+	int err;
+
+	err = pohmelfs_revents(st, POLLIN);
+	if (err)
+		goto err_out_exit;
+
+	if (st->cmd_read) {
+		err = pohmelfs_data_recv(st, cmd, sizeof(struct dnet_cmd), MSG_WAITALL);
+		if (err <= 0) {
+			if (err == 0)
+				err = -ECONNRESET;
+
+			pohmelfs_print_addr(&st->sa, "recv error: %d\n", err);
+			goto err_out_exit;
+		}
+
+		dnet_convert_cmd(cmd);
+
+		trans = cmd->trans & ~DNET_TRANS_REPLY;
+		st->cmd_read = 0;
+	}
+
+	t = pohmelfs_trans_lookup(st, cmd);
+	if (!t) {
+		pohmelfs_suck_scratch(st);
+
+		err = 0;
+		goto err_out_exit;
+	}
+	if (cmd->size && (t->io_offset != cmd->size)) {
+		err = t->cb.recv_reply(t, st);
+		if (err && (err != -EAGAIN)) {
+			pohmelfs_print_addr(&st->sa, "recv-reply error: %d\n", err);
+			goto err_out_remove;
+		}
+
+		if (t->io_offset != cmd->size)
+			goto err_out_put;
+	}
+
+	err = t->cb.complete(t, st);
+	if (err) {
+		pohmelfs_print_addr(&st->sa, "recv-complete err: %d\n", err);
+	}
+
+	kfree(t->recv_data);
+	t->recv_data = NULL;
+	t->io_offset = 0;
+
+err_out_remove:
+	/* only remove and free transaction if there is error or there will be no more replies */
+	if (!(cmd->flags & DNET_FLAGS_MORE) || err) {
+		pohmelfs_trans_remove(t);
+
+		/*
+		 * refcnt was grabbed twice:
+		 *   in pohmelfs_trans_lookup()
+		 *   and at transaction creation
+		 */
+		pohmelfs_trans_put(t);
+	}
+	st->cmd_read = 1;
+	if (err) {
+		cmd->size -= t->io_offset;
+		t->io_offset = 0;
+	}
+
+err_out_put:
+	pohmelfs_trans_put(t);
+err_out_exit:
+	return err;
+}
+
+static void pohmelfs_state_io_work(struct work_struct *work)
+{
+	struct pohmelfs_state *st = container_of(work, struct pohmelfs_state, io_work);
+	int send_err, recv_err;
+
+	send_err = recv_err = -EAGAIN;
+	while (!st->conn->psb->need_exit) {
+		send_err = pohmelfs_state_send(st);
+		if (send_err && (send_err != -EAGAIN)) {
+			pohmelfs_print_addr(&st->sa, "state send error: %d\n", send_err);
+			goto err_out_exit;
+		}
+
+		recv_err = pohmelfs_state_recv(st);
+		if (recv_err && (recv_err != -EAGAIN)) {
+			pohmelfs_print_addr(&st->sa, "state recv error: %d\n", recv_err);
+			goto err_out_exit;
+		}
+
+		if ((send_err == -EAGAIN) && (recv_err == -EAGAIN))
+			break;
+	}
+
+err_out_exit:
+	if ((send_err && (send_err != -EAGAIN)) || (recv_err && (recv_err != -EAGAIN))) {
+		pohmelfs_state_add_reconnect(st);
+	}
+	return;
+}
+
+struct pohmelfs_state *pohmelfs_addr_exist(struct pohmelfs_connection *conn, struct sockaddr_storage *sa, int addrlen)
+{
+	struct pohmelfs_state *st;
+
+	list_for_each_entry(st, &conn->state_list, state_entry) {
+		if (st->addrlen != addrlen)
+			continue;
+
+		if (!memcmp(&st->sa, sa, addrlen)) {
+			return st;
+		}
+	}
+
+	return 0;
+}
+
+struct pohmelfs_state *pohmelfs_state_create(struct pohmelfs_connection *conn, struct sockaddr_storage *sa, int addrlen,
+		int ask_route, int group_id)
+{
+	int err = 0;
+	struct pohmelfs_state *st;
+	struct sockaddr *addr = (struct sockaddr *)sa;
+
+	/* early check - this state can be inserted into route table, no need to create state and check again */
+	spin_lock(&conn->state_lock);
+	if (pohmelfs_addr_exist(conn, sa, addrlen))
+		err = -EEXIST;
+	spin_unlock(&conn->state_lock);
+
+	if (err)
+		goto err_out_exit;
+
+	st = kzalloc(sizeof(struct pohmelfs_state), GFP_KERNEL);
+	if (!st) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	st->conn = conn;
+	mutex_init(&st->trans_lock);
+	INIT_LIST_HEAD(&st->trans_list);
+	st->trans_root = RB_ROOT;
+
+	st->group_id = group_id;
+
+	kref_init(&st->refcnt);
+
+	INIT_WORK(&st->io_work, pohmelfs_state_io_work);
+
+	st->cmd_read = 1;
+
+	err = sock_create_kern(addr->sa_family, SOCK_STREAM, IPPROTO_TCP, &st->sock);
+	if (err) {
+		pohmelfs_print_addr(sa, "sock_create: failed family: %d, err: %d\n", addr->sa_family, err);
+		goto err_out_free;
+	}
+
+	st->sock->sk->sk_allocation = GFP_NOIO;
+	st->sock->sk->sk_sndtimeo = st->sock->sk->sk_rcvtimeo = msecs_to_jiffies(60000);
+
+	err = 1;
+	sock_setsockopt(st->sock, SOL_SOCKET, SO_KEEPALIVE, (char *)&err, 4);
+
+	tcp_setsockopt(st->sock->sk, SOL_TCP, TCP_KEEPIDLE, (char *)&conn->psb->keepalive_idle, 4);
+	tcp_setsockopt(st->sock->sk, SOL_TCP, TCP_KEEPINTVL, (char *)&conn->psb->keepalive_interval, 4);
+	tcp_setsockopt(st->sock->sk, SOL_TCP, TCP_KEEPCNT, (char *)&conn->psb->keepalive_cnt, 4);
+
+	err = kernel_connect(st->sock, (struct sockaddr *)addr, addrlen, 0);
+	if (err) {
+		pohmelfs_print_addr(sa, "kernel_connect: failed family: %d, err: %d\n", addr->sa_family, err);
+		goto err_out_release;
+	}
+	st->sock->sk->sk_sndtimeo = st->sock->sk->sk_rcvtimeo = msecs_to_jiffies(60000);
+
+	memcpy(&st->sa, sa, sizeof(struct sockaddr_storage));
+	st->addrlen = addrlen;
+
+	err = pohmelfs_poll_init(st);
+	if (err)
+		goto err_out_shutdown;
+
+
+	spin_lock(&conn->state_lock);
+	err = -EEXIST;
+	if (!pohmelfs_addr_exist(conn, sa, addrlen)) {
+		list_add_tail(&st->state_entry, &conn->state_list);
+		err = 0;
+	}
+	spin_unlock(&conn->state_lock);
+
+	if (err)
+		goto err_out_poll_exit;
+
+	if (ask_route) {
+		err = pohmelfs_route_request(st);
+		if (err)
+			goto err_out_poll_exit;
+	}
+
+	pohmelfs_print_addr(sa, "%d: connected\n", st->conn->idx);
+
+	return st;
+
+err_out_poll_exit:
+	pohmelfs_poll_exit(st);
+err_out_shutdown:
+	st->sock->ops->shutdown(st->sock, 2);
+err_out_release:
+	sock_release(st->sock);
+err_out_free:
+	kfree(st);
+err_out_exit:
+	if (err != -EEXIST) {
+		pohmelfs_print_addr(sa, "state creation failed: %d\n", err);
+	}
+	return ERR_PTR(err);
+}
+
+static void pohmelfs_state_exit(struct pohmelfs_state *st)
+{
+	if (!st->sock)
+		return;
+
+	pohmelfs_poll_exit(st);
+	st->sock->ops->shutdown(st->sock, 2);
+
+	pohmelfs_print_addr(&st->sa, "disconnected\n");
+	sock_release(st->sock);
+}
+
+static void pohmelfs_state_release(struct kref *kref)
+{
+	struct pohmelfs_state *st = container_of(kref, struct pohmelfs_state, refcnt);
+	pohmelfs_state_exit(st);
+}
+
+void pohmelfs_state_put(struct pohmelfs_state *st)
+{
+	kref_put(&st->refcnt, pohmelfs_state_release);
+}
+
+static void pohmelfs_state_clean(struct pohmelfs_state *st)
+{
+	struct pohmelfs_trans *t, *tmp;
+
+	pohmelfs_route_remove_all(st);
+
+	mutex_lock(&st->trans_lock);
+	list_for_each_entry_safe(t, tmp, &st->trans_list, trans_entry) {
+		list_del(&t->trans_entry);
+
+		pohmelfs_trans_put(t);
+	}
+
+	while (1) {
+		struct rb_node *n = rb_first(&st->trans_root);
+		if (!n)
+			break;
+
+		t = rb_entry(n, struct pohmelfs_trans, trans_node);
+
+		rb_erase(&t->trans_node, &st->trans_root);
+		pohmelfs_trans_put(t);
+	}
+	mutex_unlock(&st->trans_lock);
+
+	cancel_work_sync(&st->io_work);
+}
+
+void pohmelfs_state_kill(struct pohmelfs_state *st)
+{
+	BUG_ON(!list_empty(&st->state_entry));
+
+	pohmelfs_state_clean(st);
+	pohmelfs_state_put(st);
+}
+
+void pohmelfs_state_schedule(struct pohmelfs_state *st)
+{
+	if (!st->conn->need_exit)
+		queue_work(st->conn->wq, &st->io_work);
+}
+
+int pohmelfs_state_add_reconnect(struct pohmelfs_state *st)
+{
+	struct pohmelfs_connection *conn = st->conn;
+	struct pohmelfs_reconnect *r, *tmp;
+	int err = 0;
+
+	pohmelfs_route_remove_all(st);
+
+	r = kzalloc(sizeof(struct pohmelfs_reconnect), GFP_NOIO);
+	if (!r) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	memcpy(&r->sa, &st->sa, sizeof(struct sockaddr_storage));
+	r->addrlen = st->addrlen;
+	r->group_id = st->group_id;
+
+	mutex_lock(&conn->reconnect_lock);
+	list_for_each_entry(tmp, &conn->reconnect_list, reconnect_entry) {
+		if (tmp->addrlen != r->addrlen)
+			continue;
+
+		if (memcmp(&tmp->sa, &r->sa, r->addrlen))
+			continue;
+
+		err = -EEXIST;
+		break;
+	}
+
+	if (!err) {
+		list_add_tail(&r->reconnect_entry, &conn->reconnect_list);
+	}
+	mutex_unlock(&conn->reconnect_lock);
+
+	if (err)
+		goto err_out_free;
+
+	pohmelfs_print_addr(&st->sa, "reconnection added\n");
+	err = 0;
+	goto err_out_exit;
+
+err_out_free:
+	kfree(r);
+err_out_exit:
+
+	spin_lock(&conn->state_lock);
+	list_move(&st->state_entry, &conn->kill_state_list);
+	spin_unlock(&conn->state_lock);
+
+	/* we do not really care if this work will not be processed immediately */
+	queue_delayed_work(conn->wq, &conn->reconnect_work, 0);
+
+	return err;
+}
diff --git a/fs/pohmelfs/packet.h b/fs/pohmelfs/packet.h
new file mode 100644
index 0000000..f432987
--- /dev/null
+++ b/fs/pohmelfs/packet.h
@@ -0,0 +1,752 @@
+/*
+ * 2008+ Copyright (c) Evgeniy Polyakov <zbr@xxxxxxxxxxx>
+ * All rights reserved.
+ *
+ * This program 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 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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 for more details.
+ */
+
+#ifndef __DNET_PACKET_H
+#define __DNET_PACKET_H
+
+#ifndef __KERNEL__
+#include <sys/time.h>
+#include <arpa/inet.h>
+#include <sys/stat.h>
+
+#include <string.h>
+#include <stdint.h>
+
+#include <elliptics/typedefs.h>
+#include <elliptics/core.h>
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+enum dnet_commands {
+	DNET_CMD_LOOKUP = 1,			/* Lookup address by ID and per-object info: size, permissions and so on*/
+	DNET_CMD_REVERSE_LOOKUP,		/* Lookup ID by address */
+	DNET_CMD_JOIN,				/* Join the network - force remote nodes to update
+						 * their route tables to include given node with given
+						 * address
+						 */
+	DNET_CMD_WRITE,
+	DNET_CMD_READ,				/* IO commands. They have to follow by the
+						 * IO attribute which will have offset and size
+						 * parameters.
+						 */
+	DNET_CMD_LIST,				/* List all objects for given node ID */
+	DNET_CMD_EXEC,				/* Execute given command on the remote node */
+	DNET_CMD_ROUTE_LIST,			/* Receive route table from given node */
+	DNET_CMD_STAT,				/* Gather remote VM, LA and FS statistics */
+	DNET_CMD_NOTIFY,			/* Notify when object in question was modified */
+	DNET_CMD_DEL,				/* Remove given object from the storage */
+	DNET_CMD_STAT_COUNT,			/* Gather remote per-cmd statistics */
+	DNET_CMD_STATUS,			/* Change elliptics node status */
+	DNET_CMD_READ_RANGE,			/* Read range of objects */
+	DNET_CMD_DEL_RANGE,			/* Remove range of objects */
+	DNET_CMD_AUTH,				/* Authentification cookie check */
+	DNET_CMD_BULK_READ,			/* Read a number of ids at one time */
+
+	DNET_CMD_UNKNOWN,			/* This slot is allocated for statistics gathered for unknown commands */
+	__DNET_CMD_MAX,
+};
+
+enum dnet_counters {
+	DNET_CNTR_LA1 = __DNET_CMD_MAX*2,	/* Load average for 1 min */
+	DNET_CNTR_LA5,				/* Load average for 5 min */
+	DNET_CNTR_LA15,				/* Load average for 15 min */
+	DNET_CNTR_BSIZE,			/* Block size */
+	DNET_CNTR_FRSIZE,			/* Fragment size */
+	DNET_CNTR_BLOCKS,			/* Filesystem size in frsize units */
+	DNET_CNTR_BFREE,			/* # free blocks */
+	DNET_CNTR_BAVAIL,			/* # free blocks for non-root */
+	DNET_CNTR_FILES,			/* # inodes */
+	DNET_CNTR_FFREE,			/* # free inodes */
+	DNET_CNTR_FAVAIL,			/* # free inodes for non-root */
+	DNET_CNTR_FSID,				/* File system ID */
+	DNET_CNTR_VM_ACTIVE,			/* Active memory */
+	DNET_CNTR_VM_INACTIVE,			/* Inactive memory */
+	DNET_CNTR_VM_TOTAL,			/* Total memory */
+	DNET_CNTR_VM_FREE,			/* Free memory */
+	DNET_CNTR_VM_CACHED,			/* Used for cache */
+	DNET_CNTR_VM_BUFFERS,			/* Used for buffers */
+	DNET_CNTR_NODE_FILES,			/* # files in meta */
+	DNET_CNTR_NODE_LAST_MERGE,		/* Result of the last merge */
+	DNET_CNTR_NODE_CHECK_COPY,		/* Result of the last check copies */
+	DNET_CNTR_DBR_NOREC,			/* Kyoto Cabinet DB read error KCENOREC */
+	DNET_CNTR_DBR_SYSTEM,			/* Kyoto Cabinet DB read error KCESYSTEM */
+	DNET_CNTR_DBR_ERROR,			/* Kyoto Cabinet DB read error */
+	DNET_CNTR_DBW_SYSTEM,			/* Kyoto Cabinet DB write error KCESYSTEM */
+	DNET_CNTR_DBW_ERROR,			/* Kyoto Cabinet DB write error */
+	DNET_CNTR_UNKNOWN,			/* This slot is allocated for statistics gathered for unknown counters */
+	__DNET_CNTR_MAX,
+};
+
+/*
+ * Transaction ID direction bit.
+ * When set, data is a reply for the given transaction.
+ */
+#define DNET_TRANS_REPLY		0x8000000000000000ULL
+
+/*
+ * Command flags.
+ */
+
+/*
+ * When set, node will generate a reply when transaction
+ * is completed and put completion status into cmd.status
+ * field.
+ */
+#define DNET_FLAGS_NEED_ACK		(1<<0)
+
+/* There will be more commands with the same parameters (transaction number and id) */
+#define DNET_FLAGS_MORE			(1<<1)
+
+/* Transaction is about to be destroyed */
+#define DNET_FLAGS_DESTROY		(1<<2)
+
+/* Do not forward requst to antoher node even if given ID does not belong to our range */
+#define DNET_FLAGS_DIRECT		(1<<3)
+
+/* Do not locks operations - must be set for script callers or recursive operations */
+#define DNET_FLAGS_NOLOCK		(1<<4)
+
+struct dnet_id {
+	uint8_t			id[DNET_ID_SIZE];
+	uint32_t		group_id;
+	int			type;
+} __attribute__ ((packed));
+
+struct dnet_raw_id {
+	uint8_t			id[DNET_ID_SIZE];
+} __attribute__ ((packed));
+
+static inline void dnet_convert_raw_id(struct dnet_raw_id *id __attribute__ ((unused)))
+{
+}
+
+static inline void dnet_setup_id(struct dnet_id *id, unsigned int group_id, unsigned char *raw)
+{
+	memcpy(id->id, raw, DNET_ID_SIZE);
+	id->group_id = group_id;
+}
+
+struct dnet_cmd
+{
+	struct dnet_id		id;
+	uint32_t		flags;
+	int			status;
+	uint64_t		trans;
+	uint64_t		size;
+	uint8_t			data[0];
+} __attribute__ ((packed));
+
+/* kernel (pohmelfs) provides own defines for byteorder changes */
+#ifndef __KERNEL__
+#ifdef WORDS_BIGENDIAN
+
+#define dnet_bswap16(x)		((((x) >> 8) & 0xff) | (((x) & 0xff) << 8))
+
+#define dnet_bswap32(x) \
+     ((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >>  8) |		      \
+      (((x) & 0x0000ff00) <<  8) | (((x) & 0x000000ff) << 24))
+
+#define dnet_bswap64(x) \
+     ((((x) & 0xff00000000000000ull) >> 56)				      \
+      | (((x) & 0x00ff000000000000ull) >> 40)				      \
+      | (((x) & 0x0000ff0000000000ull) >> 24)				      \
+      | (((x) & 0x000000ff00000000ull) >> 8)				      \
+      | (((x) & 0x00000000ff000000ull) << 8)				      \
+      | (((x) & 0x0000000000ff0000ull) << 24)				      \
+      | (((x) & 0x000000000000ff00ull) << 40)				      \
+      | (((x) & 0x00000000000000ffull) << 56))
+#else
+#define dnet_bswap16(x) (x)
+#define dnet_bswap32(x) (x)
+#define dnet_bswap64(x) (x)
+#endif
+#endif
+
+static inline void dnet_convert_id(struct dnet_id *id)
+{
+	id->group_id = dnet_bswap32(id->group_id);
+	id->type = dnet_bswap32(id->type);
+}
+
+static inline void dnet_convert_cmd(struct dnet_cmd *cmd)
+{
+	dnet_convert_id(&cmd->id);
+	cmd->flags = dnet_bswap32(cmd->flags);
+	cmd->status = dnet_bswap32(cmd->status);
+	cmd->size = dnet_bswap64(cmd->size);
+	cmd->trans = dnet_bswap64(cmd->trans);
+}
+
+/* Completely remove object history and metadata */
+#define DNET_ATTR_DELETE_HISTORY		(1<<0)
+
+/* What type of counters to fetch */
+#define DNET_ATTR_CNTR_GLOBAL			(1<<0)
+
+/* Bulk request for checking files */
+#define DNET_ATTR_BULK_CHECK			(1<<0)
+
+/* Fill ctime/mtime from metadata when processing DNET_CMD_LOOKUP */
+#define DNET_ATTR_META_TIMES			(1<<1)
+
+/* Do not verify checksum */
+#define DNET_ATTR_NOCSUM			(1<<2)
+
+/*
+ * ascending sort data before returning range request to user
+ * c++ bindings only
+ */
+#define DNET_ATTR_SORT				(1<<3)
+
+/*
+ * This flag will force its parent CMD not to lock operation
+ * Flag will be propagated to cmd->flags
+ */
+#define DNET_ATTR_NOLOCK			(1<<4)
+
+struct dnet_attr
+{
+	uint64_t		size;
+	uint32_t		cmd;
+	uint32_t		flags;
+	uint32_t		unused[2];
+} __attribute__ ((packed));
+
+static inline void dnet_convert_attr(struct dnet_attr *a)
+{
+	a->size = dnet_bswap64(a->size);
+	a->cmd = dnet_bswap32(a->cmd);
+	a->flags = dnet_bswap32(a->flags);
+}
+
+#define DNET_ADDR_SIZE		28
+
+struct dnet_addr
+{
+	uint8_t			addr[DNET_ADDR_SIZE];
+	uint32_t		addr_len;
+} __attribute__ ((packed));
+
+struct dnet_list
+{
+	struct dnet_id		id;
+	uint32_t		size;
+	uint8_t			data[0];
+} __attribute__ ((packed));
+
+static inline void dnet_convert_list(struct dnet_list *l)
+{
+	dnet_convert_id(&l->id);
+	l->size = dnet_bswap32(l->size);
+}
+
+struct dnet_addr_attr
+{
+	uint16_t		sock_type;
+	uint16_t		family;
+	uint32_t		proto;
+	struct dnet_addr	addr;
+} __attribute__ ((packed));
+
+static inline void dnet_convert_addr_attr(struct dnet_addr_attr *a)
+{
+	a->addr.addr_len = dnet_bswap32(a->addr.addr_len);
+	a->proto = dnet_bswap32(a->proto);
+	a->sock_type = dnet_bswap16(a->sock_type);
+	a->family = dnet_bswap16(a->family);
+}
+
+struct dnet_addr_cmd
+{
+	struct dnet_cmd		cmd;
+	struct dnet_attr	a;
+	struct dnet_addr_attr	addr;
+} __attribute__ ((packed));
+
+static inline void dnet_convert_addr_cmd(struct dnet_addr_cmd *l)
+{
+	dnet_convert_cmd(&l->cmd);
+	dnet_convert_attr(&l->a);
+	dnet_convert_addr_attr(&l->addr);
+}
+
+/* Do not update history for given transaction */
+#define DNET_IO_FLAGS_SKIP_SENDING	(1<<0)
+
+/* Append given data at the end of the object */
+#define DNET_IO_FLAGS_APPEND		(1<<1)
+
+#define DNET_IO_FLAGS_COMPRESS		(1<<2)
+
+/* Metada IO request */
+#define DNET_IO_FLAGS_META		(1<<3)
+
+/* eblob prepare/commit phase */
+#define DNET_IO_FLAGS_PREPARE		(1<<4)
+#define DNET_IO_FLAGS_COMMIT		(1<<5)
+
+/* Object was removed */
+#define DNET_IO_FLAGS_REMOVED		(1<<6)
+
+/* Overwrite data */
+#define DNET_IO_FLAGS_OVERWRITE		(1<<7)
+
+/* Do not checksum data */
+#define DNET_IO_FLAGS_NOCSUM		(1<<8)
+
+/*
+ * this flag is used when we want backend not to perform any additional actions
+ * except than write data at given offset. This is no-op in filesystem backend,
+ * but eblob one should disable prepare/commit operations.
+ */
+#define DNET_IO_FLAGS_PLAIN_WRITE	(1<<9)
+
+/* Do not really send data in range request.
+ * Send only statistics instead.
+ *
+ * -- we do not care if it matches above DNET_IO_FLAGS_PLAIN_WRITE,
+ *  since using plain write and nodata (read) is useless anyway
+ */
+#define DNET_IO_FLAGS_NODATA		(1<<9)
+
+struct dnet_io_attr
+{
+	uint8_t			parent[DNET_ID_SIZE];
+	uint8_t			id[DNET_ID_SIZE];
+
+	/*
+	 * used in range request as start and number for LIMIT(start, num) 
+	 *
+	 * write prepare request uses @num is used as a placeholder
+	 * for number of bytes to reserve on disk
+	 */
+	uint64_t		start, num;
+	int			type;
+	uint32_t		flags;
+	uint64_t		offset;
+	uint64_t		size;
+} __attribute__ ((packed));
+
+static inline void dnet_convert_io_attr(struct dnet_io_attr *a)
+{
+	a->start = dnet_bswap64(a->start);
+	a->num = dnet_bswap64(a->num);
+
+	a->flags = dnet_bswap32(a->flags);
+	a->offset = dnet_bswap64(a->offset);
+	a->size = dnet_bswap64(a->size);
+}
+
+struct dnet_history_entry
+{
+	uint8_t			id[DNET_ID_SIZE];
+	uint32_t		flags;
+	uint64_t		reserved;
+	uint64_t		tsec, tnsec;
+	uint64_t		offset;
+	uint64_t		size;
+} __attribute__ ((packed));
+
+/*
+ * Helper structure and set of functions to map history file and perform basic checks.
+ */
+struct dnet_history_map
+{
+	struct dnet_history_entry	*ent;
+	long				num;
+	ssize_t				size;
+	int				fd;
+};
+
+static inline void dnet_convert_history_entry(struct dnet_history_entry *a)
+{
+	a->flags = dnet_bswap32(a->flags);
+	a->offset = dnet_bswap64(a->offset);
+	a->size = dnet_bswap64(a->size);
+	a->tsec = dnet_bswap64(a->tsec);
+	a->tnsec = dnet_bswap64(a->tnsec);
+}
+
+static inline void dnet_setup_history_entry(struct dnet_history_entry *e,
+		unsigned char *id, uint64_t size, uint64_t offset,
+		struct timespec *ts, uint32_t flags)
+{
+	if (!ts) {
+		struct timeval tv;
+
+		gettimeofday(&tv, NULL);
+
+		e->tsec = tv.tv_sec;
+		e->tnsec = tv.tv_usec * 1000;
+	} else {
+		e->tsec = ts->tv_sec;
+		e->tnsec = ts->tv_nsec;
+	}
+
+	memcpy(e->id, id, DNET_ID_SIZE);
+
+	e->size = size;
+	e->offset = offset;
+	e->flags = flags;
+	e->reserved = 0;
+
+	dnet_convert_history_entry(e);
+}
+
+struct dnet_stat
+{
+	/* Load average from the target system multiplied by 100 */
+	uint16_t		la[3];
+
+	uint16_t		namemax;	/* maximum filename length */
+
+	uint64_t		bsize;		/* Block size */
+	uint64_t		frsize;		/* Fragment size */
+	uint64_t		blocks;		/* Filesystem size in frsize units */
+	uint64_t		bfree;		/* # free blocks */
+	uint64_t		bavail;		/* # free blocks for non-root */
+	uint64_t		files;		/* # inodes */
+	uint64_t		ffree;		/* # free inodes */
+	uint64_t		favail;		/* # free inodes for non-root */
+	uint64_t		fsid;		/* file system ID */
+	uint64_t		flag;		/* mount flags */
+
+	/*
+	 * VM counters in KB (1024) units.
+	 * On FreeBSD vm_buffers is used for wire counter.
+	 */
+	uint64_t		vm_active;
+	uint64_t		vm_inactive;
+	uint64_t		vm_total;
+	uint64_t		vm_free;
+	uint64_t		vm_cached;
+	uint64_t		vm_buffers;
+
+	/*
+	 * Per node IO statistics will live here.
+	 * Reserved for future use.
+	 */
+	uint64_t		reserved[32];
+};
+
+static inline void dnet_convert_stat(struct dnet_stat *st)
+{
+	int i;
+
+	for (i=0; i<3; ++i)
+		st->la[i] = dnet_bswap16(st->la[i]);
+
+	st->bsize = dnet_bswap64(st->bsize);
+	st->frsize = dnet_bswap64(st->frsize);
+	st->blocks = dnet_bswap64(st->blocks);
+	st->bfree = dnet_bswap64(st->bfree);
+	st->bavail = dnet_bswap64(st->bavail);
+	st->files = dnet_bswap64(st->files);
+	st->ffree = dnet_bswap64(st->ffree);
+	st->favail = dnet_bswap64(st->favail);
+	st->fsid = dnet_bswap64(st->fsid);
+	st->namemax = dnet_bswap16(st->namemax);
+
+	st->vm_active = dnet_bswap64(st->vm_active);
+	st->vm_inactive = dnet_bswap64(st->vm_inactive);
+	st->vm_total = dnet_bswap64(st->vm_total);
+	st->vm_free = dnet_bswap64(st->vm_free);
+	st->vm_buffers = dnet_bswap64(st->vm_buffers);
+	st->vm_cached = dnet_bswap64(st->vm_cached);
+}
+
+struct dnet_io_notification
+{
+	struct dnet_addr_attr		addr;
+	struct dnet_io_attr		io;
+};
+
+static inline void dnet_convert_io_notification(struct dnet_io_notification *n)
+{
+	dnet_convert_addr_attr(&n->addr);
+	dnet_convert_io_attr(&n->io);
+}
+
+struct dnet_stat_count
+{
+	uint64_t			count;
+	uint64_t			err;
+};
+
+static inline void dnet_convert_stat_count(struct dnet_stat_count *st, int num)
+{
+	int i;
+
+	for (i=0; i<num; ++i) {
+		st[i].count = dnet_bswap64(st[i].count);
+		st[i].err = dnet_bswap64(st[i].err);
+	}
+}
+
+struct dnet_addr_stat
+{
+	struct dnet_addr		addr;
+	int				num;
+	int				cmd_num;
+	struct dnet_stat_count		count[0];
+} __attribute__ ((packed));
+
+static inline void dnet_convert_addr_stat(struct dnet_addr_stat *st, int num)
+{
+	st->addr.addr_len = dnet_bswap32(st->addr.addr_len);
+	st->num = dnet_bswap32(st->num);
+	if (!num)
+		num = st->num;
+	st->cmd_num = dnet_bswap32(st->cmd_num);
+
+	dnet_convert_stat_count(st->count, num);
+}
+
+static inline void dnet_stat_inc(struct dnet_stat_count *st, int cmd, int err)
+{
+	if (cmd >= __DNET_CMD_MAX)
+		cmd = DNET_CMD_UNKNOWN;
+
+	if (!err)
+		st[cmd].count++;
+	else
+		st[cmd].err++;
+}
+
+struct dnet_time {
+	uint64_t		tsec, tnsec;
+};
+
+static inline void dnet_convert_time(struct dnet_time *tm)
+{
+	tm->tsec = dnet_bswap64(tm->tsec);
+	tm->tnsec = dnet_bswap64(tm->tnsec);
+}
+
+static inline void dnet_current_time(struct dnet_time *t)
+{
+	struct timeval tv;
+
+	gettimeofday(&tv, NULL);
+
+	t->tsec = tv.tv_sec;
+	t->tnsec = tv.tv_usec * 1000;
+}
+
+struct dnet_file_info {
+	int			flen;		/* filename length, which goes after this structure */
+	unsigned char		checksum[DNET_CSUM_SIZE];
+
+	unsigned int		nlink;
+
+	uint64_t		mode;
+
+	uint64_t		dev;
+	uint64_t		rdev;
+
+	uint64_t		ino;
+
+	uint64_t		uid;
+	uint64_t		gid;
+
+	uint64_t		blksize;
+	uint64_t		blocks;
+
+	uint64_t		size;
+	uint64_t		offset;		/* offset within eblob */
+
+	struct dnet_time	atime;
+	struct dnet_time	ctime;
+	struct dnet_time	mtime;
+};
+
+static inline void dnet_convert_file_info(struct dnet_file_info *info)
+{
+	info->flen = dnet_bswap32(info->flen);
+	info->nlink = dnet_bswap32(info->nlink);
+
+	info->mode = dnet_bswap64(info->mode);
+	info->dev = dnet_bswap64(info->dev);
+	info->ino = dnet_bswap64(info->ino);
+	info->uid = dnet_bswap64(info->uid);
+	info->gid = dnet_bswap64(info->gid);
+	info->blksize = dnet_bswap64(info->blksize);
+	info->blocks = dnet_bswap64(info->blocks);
+	info->rdev = dnet_bswap64(info->rdev);
+	info->size = dnet_bswap64(info->size);
+	info->offset = dnet_bswap64(info->offset);
+
+	dnet_convert_time(&info->atime);
+	dnet_convert_time(&info->ctime);
+	dnet_convert_time(&info->mtime);
+}
+
+static inline void dnet_info_from_stat(struct dnet_file_info *info, struct stat *st)
+{
+	info->nlink = st->st_nlink;
+	info->mode = st->st_mode;
+	info->dev = st->st_dev;
+	info->ino = st->st_ino;
+	info->uid = st->st_uid;
+	info->gid = st->st_gid;
+	info->blksize = st->st_blksize;
+	info->blocks = st->st_blocks;
+	info->rdev = st->st_rdev;
+	info->size = st->st_size;
+	info->offset = 0;
+
+	info->atime.tsec = st->st_atime;
+	info->ctime.tsec = st->st_ctime;
+	info->mtime.tsec = st->st_mtime;
+
+	info->atime.tnsec = 0;
+	info->ctime.tnsec = 0;
+	info->mtime.tnsec = 0;
+}
+
+/* Elliptics node status - if set, status will be changed */
+#define DNET_ATTR_STATUS_CHANGE		(1<<0)
+
+/* Elliptics node should exit */
+#define DNET_STATUS_EXIT		(1<<0)
+
+/* Ellipitcs node goes ro/rw */
+#define DNET_STATUS_RO			(1<<1)
+
+struct dnet_node_status {
+	int nflags;
+	int status_flags;  /* DNET_STATUS_EXIT, DNET_STATUS_RO should be specified here */
+	uint32_t log_mask;
+};
+
+static inline void dnet_convert_node_status(struct dnet_node_status *st)
+{
+	st->nflags = dnet_bswap32(st->nflags);
+	st->status_flags = dnet_bswap32(st->status_flags);
+	st->log_mask = dnet_bswap32(st->log_mask);
+}
+
+enum cmd_type {
+	DNET_EXEC_SHELL = 0,
+	DNET_EXEC_PYTHON_SCRIPT_NAME,
+	DNET_EXEC_PYTHON,
+};
+
+struct dnet_exec {
+	int			type;
+	int			flags;
+	uint64_t		script_size, name_size, binary_size;
+	uint64_t		reserved[2];
+
+	/*
+	 * we pack script name first, then user's script content and then binary data,
+	 * which will be pushed into server's object
+	 */
+	char			data[0];
+} __attribute__((packed));
+
+static inline void dnet_convert_exec(struct dnet_exec *e)
+{
+	e->type = dnet_bswap32(e->type);
+	e->script_size = dnet_bswap64(e->script_size);
+	e->name_size = dnet_bswap64(e->name_size);
+	e->binary_size = dnet_bswap64(e->binary_size);
+	e->flags = dnet_bswap32(e->flags);
+}
+
+#define DNET_AUTH_COOKIE_SIZE	32
+
+struct dnet_auth {
+	char			cookie[DNET_AUTH_COOKIE_SIZE];
+	uint64_t		flags;
+	uint64_t		unused[3];
+};
+
+static inline void dnet_convert_auth(struct dnet_auth *a)
+{
+	a->flags = dnet_bswap64(a->flags);
+}
+
+enum dnet_meta_types {
+	DNET_META_PARENT_OBJECT = 1,	/* parent object name */
+	DNET_META_GROUPS,		/* this object has copies in given groups */
+	DNET_META_CHECK_STATUS,		/* last checking status: timestamp and so on */
+	DNET_META_NAMESPACE,		/* namespace where given object lives */
+	DNET_META_UPDATE,		/* last update information (timestamp, flags) */
+	DNET_META_CHECKSUM,		/* checksum (sha512) of the whole data object calculated on server */
+	__DNET_META_MAX,
+};
+
+struct dnet_meta
+{
+	uint32_t			type;
+	uint32_t			size;
+	uint64_t			common;
+	uint8_t				tmp[16];
+	uint8_t				data[0];
+} __attribute__ ((packed));
+
+static inline void dnet_convert_meta(struct dnet_meta *m)
+{
+	m->type = dnet_bswap32(m->type);
+	m->size = dnet_bswap32(m->size);
+	m->common = dnet_bswap64(m->common);
+}
+
+struct dnet_meta_update {
+	int			unused_gap;
+	int			group_id;
+	uint64_t		flags;
+	struct dnet_time	tm;
+	uint64_t		reserved[4];
+} __attribute__((packed));
+
+static inline void dnet_convert_meta_update(struct dnet_meta_update *m)
+{
+	dnet_convert_time(&m->tm);
+	m->flags = dnet_bswap64(m->flags);
+}
+
+struct dnet_meta_check_status {
+	int			status;
+	int			pad;
+	struct dnet_time	tm;
+	uint64_t		reserved[4];
+} __attribute__ ((packed));
+
+static inline void dnet_convert_meta_check_status(struct dnet_meta_check_status *c)
+{
+	c->status = dnet_bswap32(c->status);
+	dnet_convert_time(&c->tm);
+}
+
+struct dnet_meta_checksum {
+	uint8_t			checksum[DNET_CSUM_SIZE];
+	struct dnet_time	tm;
+} __attribute__ ((packed));
+
+static inline void dnet_convert_meta_checksum(struct dnet_meta_checksum *c)
+{
+	dnet_convert_time(&c->tm);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __DNET_PACKET_H */
diff --git a/fs/pohmelfs/pohmelfs.h b/fs/pohmelfs/pohmelfs.h
new file mode 100644
index 0000000..3b30a59
--- /dev/null
+++ b/fs/pohmelfs/pohmelfs.h
@@ -0,0 +1,503 @@
+/*
+ * Copyright (C) 2011+ Evgeniy Polyakov <zbr@xxxxxxxxxxx>
+ */
+
+#ifndef __POHMELFS_H
+#define __POHMELFS_H
+
+#include <linux/backing-dev.h>
+#include <linux/crypto.h>
+#include <linux/fs.h>
+#include <linux/kref.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/net.h>
+#include <linux/pagemap.h>
+#include <linux/pagevec.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/wait.h>
+#include <linux/workqueue.h>
+
+#include <crypto/sha.h>
+
+#define dnet_bswap16(x)		cpu_to_le16(x)
+#define dnet_bswap32(x)		cpu_to_le32(x)
+#define dnet_bswap64(x)		cpu_to_le64(x)
+
+/* theese are needed for packet.h below to compile */
+#define DNET_ID_SIZE	SHA512_DIGEST_SIZE
+#define DNET_CSUM_SIZE	SHA512_DIGEST_SIZE
+
+#define POHMELFS_INODE_COLUMN		3
+
+/*
+ * is not used in kernel, but we want to share the same header
+ * with userspace, so I put it here for compiler to shut up
+ */
+int gettimeofday(struct timeval *, struct timezone *);
+
+#include "packet.h"
+
+static inline struct timespec pohmelfs_date(struct dnet_time *tm)
+{
+	struct timespec ts;
+
+	ts.tv_sec = tm->tsec;
+	ts.tv_nsec = tm->tnsec;
+
+	return ts;
+}
+
+struct pohmelfs_cmd {
+	struct dnet_cmd		cmd;
+	struct dnet_attr	attr;
+	union {
+		struct dnet_io_attr	io;
+	} p;
+};
+
+/*
+ * Compare two IDs.
+ * Returns  1 when id1 > id2
+ *         -1 when id1 < id2
+ *          0 when id1 = id2
+ */
+static inline int dnet_id_cmp_str(const unsigned char *id1, const unsigned char *id2)
+{
+	unsigned int i = 0;
+
+	for (i*=sizeof(unsigned long); i<DNET_ID_SIZE; ++i) {
+		if (id1[i] < id2[i])
+			return -1;
+		if (id1[i] > id2[i])
+			return 1;
+	}
+
+	return 0;
+}
+
+struct pohmelfs_state;
+struct pohmelfs_sb;
+struct pohmelfs_trans;
+
+struct pohmelfs_trans_cb {
+	int				(* init)(struct pohmelfs_trans *t);
+	int				(* complete)(struct pohmelfs_trans *t, struct pohmelfs_state *recv);
+	int				(* recv_reply)(struct pohmelfs_trans *t, struct pohmelfs_state *recv);
+	void				(* destroy)(struct pohmelfs_trans *t);
+};
+
+struct pohmelfs_trans {
+	struct list_head	trans_entry;
+	struct rb_node		trans_node;
+
+	struct kref		refcnt;
+
+	unsigned long		trans;
+
+	struct inode		*inode;
+
+	struct pohmelfs_state	*st;
+
+	struct pohmelfs_cmd	cmd;
+
+	u64			header_size, data_size;
+
+	unsigned long long	io_offset;
+
+	void			*data;
+	void			*recv_data;
+
+	struct pohmelfs_write_ctl	*wctl;
+	void			*priv;
+
+	struct pohmelfs_trans_cb	cb;
+};
+
+struct pohmelfs_trans *pohmelfs_trans_alloc(struct inode *inode);
+struct pohmelfs_trans *pohmelfs_trans_alloc_io_buf(struct inode *inode, int group, int command,
+		void *data, u64 offset, u64 size, int aflags, int ioflags, int type);
+void pohmelfs_trans_put(struct pohmelfs_trans *t);
+
+int pohmelfs_trans_insert(struct pohmelfs_trans *t);
+int pohmelfs_trans_insert_tree(struct pohmelfs_state *st, struct pohmelfs_trans *t);
+void pohmelfs_trans_remove(struct pohmelfs_trans *t);
+struct pohmelfs_trans *pohmelfs_trans_lookup(struct pohmelfs_state *st, struct dnet_cmd *cmd);
+
+struct pohmelfs_state {
+	struct pohmelfs_connection	*conn;
+	struct list_head	state_entry;
+
+	struct sockaddr_storage	sa;
+	int			addrlen;
+	struct socket		*sock;
+
+	int			group_id;
+
+	struct mutex		trans_lock;
+	struct list_head	trans_list;
+	struct rb_root		trans_root;
+
+	struct kref		refcnt;
+
+	int			routes;
+
+	/* Waiting/polling machinery */
+	wait_queue_t		wait;
+	wait_queue_head_t	*whead;
+
+	struct work_struct	io_work;
+
+	/* is set when dnet_cmd is being read, otherwise attached data */
+	int			cmd_read;
+	/* currently read command reply */
+	struct dnet_cmd		cmd;
+
+	uint64_t		bsize;		/* Block size */
+	uint64_t		frsize;		/* Fragment size */
+	uint64_t		blocks;		/* Filesystem size in frsize units */
+	uint64_t		bfree;		/* # free blocks */
+	uint64_t		bavail;		/* # free blocks for non-root */
+};
+
+struct pohmelfs_state *pohmelfs_state_create(struct pohmelfs_connection *conn, struct sockaddr_storage *sa, int addrlen,
+		int ask_route, int group_id);
+struct pohmelfs_state *pohmelfs_state_lookup(struct pohmelfs_sb *psb, struct dnet_raw_id *id, int group, ssize_t size);
+int pohmelfs_grab_states(struct pohmelfs_sb *psb, struct pohmelfs_state ***stp);
+
+static inline void pohmelfs_state_get(struct pohmelfs_state *st)
+{
+	kref_get(&st->refcnt);
+}
+
+void pohmelfs_state_put(struct pohmelfs_state *st);
+void pohmelfs_state_kill(struct pohmelfs_state *st);
+
+struct pohmelfs_state *pohmelfs_addr_exist(struct pohmelfs_connection *conn, struct sockaddr_storage *sa, int addrlen);
+
+void pohmelfs_state_schedule(struct pohmelfs_state *st);
+
+__attribute__ ((format (printf, 2, 3))) void pohmelfs_print_addr(struct sockaddr_storage *addr, const char *fmt, ...);
+
+#define POHMELFS_INODE_INFO_REMOVED		(1<<0)
+
+struct pohmelfs_inode_info {
+	struct dnet_raw_id	id;
+
+	unsigned int		mode;
+	unsigned int		nlink;
+	unsigned int		uid;
+	unsigned int		gid;
+	unsigned int		blocksize;
+	unsigned int		namelen;
+	__u64			ino;
+	__u64			blocks;
+	__u64			rdev;
+	__u64			size;
+	__u64			version;
+
+	__u64			flags;
+
+	struct dnet_time	ctime;
+	struct dnet_time	mtime;
+	struct dnet_time	atime;
+} __attribute__ ((packed));
+
+void pohmelfs_fill_inode_info(struct inode *inode, struct pohmelfs_inode_info *info);
+void pohmelfs_fill_inode(struct inode *inode, struct pohmelfs_inode_info *info);
+void pohmelfs_convert_inode_info(struct pohmelfs_inode_info *info);
+
+struct pohmelfs_inode {
+	struct inode		vfs_inode;
+	struct dnet_raw_id	id;
+
+	struct rb_node		node;
+
+	struct mutex		lock;
+
+	int			*groups;
+	int			group_num;
+
+	time_t			update;
+	int			local;
+};
+
+int pohmelfs_send_dentry(struct pohmelfs_inode *pi, struct dnet_raw_id *id, const char *sname, int len, int sync);
+struct pohmelfs_inode *pohmelfs_sb_inode_lookup(struct pohmelfs_sb *psb, struct dnet_raw_id *id);
+
+struct pohmelfs_reconnect {
+	struct list_head	reconnect_entry;
+	struct sockaddr_storage	sa;
+	int			addrlen;
+	int			group_id;
+};
+
+int pohmelfs_state_add_reconnect(struct pohmelfs_state *st);
+
+struct pohmelfs_path {
+	struct mutex		lock;
+	char			*data;
+};
+
+int pohmelfs_http_compat_id(struct pohmelfs_inode *pi);
+
+struct pohmelfs_addr {
+	struct list_head	addr_entry;
+	struct sockaddr_storage	sa;
+	int			addrlen;
+};
+
+struct pohmelfs_connection {
+	struct pohmelfs_sb	*psb;
+
+	int			idx;
+
+	struct rb_root		route_root;
+	struct list_head	state_list;
+	spinlock_t		state_lock;
+
+	struct mutex		reconnect_lock;
+	struct list_head	reconnect_list;
+	struct list_head	kill_state_list;
+
+	struct workqueue_struct	*wq;
+
+	int			need_exit;
+	struct delayed_work	reconnect_work;
+};
+
+void pohmelfs_pool_clean(struct pohmelfs_connection *conn, int conn_num);
+int pohmelfs_pool_resize(struct pohmelfs_sb *psb, int num);
+
+struct pohmelfs_sb {
+	struct super_block	*sb;
+	struct backing_dev_info	bdi;
+
+	struct pohmelfs_inode	*root;
+
+	spinlock_t		inode_lock;
+	struct rb_root		inode_root;
+
+	int			http_compat;
+	struct pohmelfs_path	*path;
+
+	int			bdi_num;
+
+	struct pohmelfs_connection	*conn;
+	int			conn_num;
+	int			bulk_idx, bulk_num;
+	int			meta_idx, meta_num;
+	struct mutex		conn_lock;
+
+	/* protected by conn_lock */
+	struct list_head	addr_list;
+
+	long			read_wait_timeout;
+	long			write_wait_timeout;
+	long			sync_timeout;
+	long			reconnect_timeout;
+
+	int			need_exit;
+	struct delayed_work	sync_work;
+	struct workqueue_struct	*wq;
+
+	char			*fsid;
+	int			fsid_len;
+
+	atomic_long_t		ino;
+	atomic_long_t		trans;
+
+	struct crypto_hash	*hash;
+
+	int			*groups;
+	int			group_num;
+
+	/*
+	 * number of copies to be successfully written to mark write as successful
+	 * if not set, half of groups plus one must be successfully written, i.e. plain write quorum
+	 */
+	int			successful_write_count;
+	int			keepalive_cnt, keepalive_interval, keepalive_idle;
+	int			readdir_allocation;
+	int			sync_on_close;
+	int			no_read_csum;
+};
+
+static inline struct pohmelfs_sb *pohmelfs_sb(struct super_block *sb)
+{
+	return (struct pohmelfs_sb *)sb->s_fs_info;
+}
+
+static inline struct pohmelfs_inode *pohmelfs_inode(struct inode *inode)
+{
+	return container_of(inode, struct pohmelfs_inode, vfs_inode);
+}
+
+struct pohmelfs_wait {
+	wait_queue_head_t	wq;
+	struct pohmelfs_inode	*pi;
+	void			*ret;
+	atomic_long_t		count;
+	int			condition;
+	struct kref		refcnt;
+};
+
+int pohmelfs_wait_init(struct pohmelfs_wait *wait, struct pohmelfs_inode *pi);
+struct pohmelfs_wait *pohmelfs_wait_alloc(struct pohmelfs_inode *pi);
+void pohmelfs_wait_put(struct pohmelfs_wait *wait);
+static inline void pohmelfs_wait_get(struct pohmelfs_wait *wait)
+{
+	kref_get(&wait->refcnt);
+}
+
+struct pohmelfs_inode_info_binary_package {
+	struct pohmelfs_inode_info	info;
+
+	struct pohmelfs_wait		wait;
+};
+
+struct pohmelfs_write_ctl {
+	struct pagevec			pvec;
+	struct pohmelfs_inode_info	*info;
+
+	struct kref			refcnt;
+	atomic_t			good_writes;
+};
+
+struct pohmelfs_dentry_disk {
+	struct dnet_raw_id		id;
+	uint64_t			ino;
+	int				type;
+	int				len;
+	char				name[0];
+} __attribute__((packed));
+
+struct pohmelfs_dentry {
+	struct dnet_raw_id		parent_id;
+	struct pohmelfs_dentry_disk	disk;
+};
+
+extern struct kmem_cache *pohmelfs_inode_cache;
+extern struct kmem_cache *pohmelfs_trans_cache;
+extern struct kmem_cache *pohmelfs_inode_info_cache;
+extern struct kmem_cache *pohmelfs_route_cache;
+extern struct kmem_cache *pohmelfs_wait_cache;
+extern struct kmem_cache *pohmelfs_io_cache;
+extern struct kmem_cache *pohmelfs_inode_info_binary_package_cache;
+extern struct kmem_cache *pohmelfs_write_cache;
+extern struct kmem_cache *pohmelfs_dentry_cache;
+
+struct inode *pohmelfs_alloc_inode(struct super_block *sb);
+void pohmelfs_destroy_inode(struct inode *);
+
+struct pohmelfs_inode *pohmelfs_existing_inode(struct pohmelfs_sb *psb, struct pohmelfs_inode_info *info);
+struct pohmelfs_inode *pohmelfs_new_inode(struct pohmelfs_sb *psb, int mode);
+int pohmelfs_hash(struct pohmelfs_sb *psb, const void *data, const size_t size, struct dnet_raw_id *id);
+
+char *pohmelfs_dump_id(const unsigned char *id);
+char *pohmelfs_dump_id_len_raw(const unsigned char *id, unsigned int len, char *dst);
+
+int pohmelfs_write_command(struct pohmelfs_inode *pi, struct pohmelfs_write_ctl *ctl, loff_t offset, size_t len);
+void pohmelfs_write_ctl_release(struct kref *kref);
+int pohmelfs_metadata_inode(struct pohmelfs_inode *pi, int sync);
+
+extern const struct file_operations pohmelfs_dir_fops;
+extern const struct inode_operations pohmelfs_dir_inode_operations;
+
+extern const struct file_operations pohmelfs_file_ops;
+extern const struct inode_operations pohmelfs_file_inode_operations;
+
+extern const struct inode_operations pohmelfs_symlink_inode_operations;
+extern const struct inode_operations pohmelfs_special_inode_operations;
+
+extern void *pohmelfs_scratch_buf;
+extern int pohmelfs_scratch_buf_size;
+
+/*
+ * if this flag is set, pohmelfs_inode_info->data is owned by the caller,
+ * so sending path may use it on its own and free (using kfree) when it's done
+ *
+ * This logic does not work for shared buffers or
+ * when multiple transactions will be sent for single pohmelfs_inode_info
+ */
+#define POHMELFS_IO_OWN			(1<<0)
+
+struct pohmelfs_io {
+	struct pohmelfs_inode		*pi;
+
+	struct dnet_raw_id		*id;
+
+	int				cmd;
+	int				type;
+
+	u64				offset, size;
+	u64				start, num;
+
+	u32				cflags;
+	u32				aflags;
+	u32				ioflags;
+
+	int				group_id;
+
+	u32				alloc_flags;
+	void				*data;
+
+	struct pohmelfs_write_ctl	*wctl;
+	void				*priv;
+
+	struct pohmelfs_trans_cb	cb;
+};
+
+int pohmelfs_send_io_group(struct pohmelfs_io *pio, int group_id);
+int pohmelfs_send_io(struct pohmelfs_io *pio);
+int pohmelfs_send_buf_single(struct pohmelfs_io *pio, struct pohmelfs_state *st);
+int pohmelfs_send_buf(struct pohmelfs_io *pio);
+
+int pohmelfs_data_recv(struct pohmelfs_state *st, void *buf, u64 size, unsigned int flags);
+int pohmelfs_recv(struct pohmelfs_trans *t, struct pohmelfs_state *recv, void *data, int size);
+
+struct pohmelfs_route {
+	struct rb_node			node;
+	int				group_id;
+	struct dnet_raw_id		id;
+	struct pohmelfs_state		*st;
+};
+
+int pohmelfs_route_request(struct pohmelfs_state *st);
+void pohmelfs_route_remove_all(struct pohmelfs_state *st);
+
+struct pohmelfs_script_req {
+	char			*obj_name;
+	int			obj_len;
+
+	char			*script_name;
+	int			script_namelen;
+
+	void			*binary;
+	int			binary_size;
+
+	int			group_id;
+
+	unsigned int		cflags;
+	int			sync;
+
+	struct dnet_raw_id	*id;
+
+	int			(* complete)(struct pohmelfs_trans *t, struct pohmelfs_state *recv);
+	void			*ret;
+	int			ret_cond;
+};
+
+int pohmelfs_send_script_request(struct pohmelfs_inode *parent, struct pohmelfs_script_req *req);
+
+int pohmelfs_stat(struct pohmelfs_sb *psb, int sync);
+
+static inline int pohmelfs_need_resync(struct pohmelfs_inode *pi)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(pi->vfs_inode.i_sb);
+	return get_seconds() > pi->update + psb->sync_timeout;
+}
+
+#endif /* __POHMELFS_H */
diff --git a/fs/pohmelfs/pool.c b/fs/pohmelfs/pool.c
new file mode 100644
index 0000000..c4572c7
--- /dev/null
+++ b/fs/pohmelfs/pool.c
@@ -0,0 +1,159 @@
+/*
+ * Copyright (C) 2011+ Evgeniy Polyakov <zbr@xxxxxxxxxxx>
+ */
+
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <linux/net.h>
+
+#include <net/sock.h>
+#include <net/tcp.h>
+
+#include "pohmelfs.h"
+
+static void pohmelfs_reconnect(struct work_struct *work)
+{
+	struct pohmelfs_connection *conn = container_of(to_delayed_work(work), struct pohmelfs_connection, reconnect_work);
+	struct pohmelfs_reconnect *r, *tmp;
+	struct pohmelfs_state *st, *stmp;
+	LIST_HEAD(head);
+	int err;
+
+	mutex_lock(&conn->reconnect_lock);
+	list_for_each_entry_safe(r, tmp, &conn->reconnect_list, reconnect_entry) {
+		st = pohmelfs_state_create(conn, &r->sa, r->addrlen, 1, r->group_id);
+		if (IS_ERR(st)) {
+			err = PTR_ERR(st);
+
+			if (err != -EEXIST)
+				continue;
+		} else {
+			pohmelfs_print_addr(&st->sa, "reconnected\n");
+		}
+
+		list_del(&r->reconnect_entry);
+		kfree(r);
+	}
+	mutex_unlock(&conn->reconnect_lock);
+
+	spin_lock(&conn->state_lock);
+	list_for_each_entry_safe(st, stmp, &conn->kill_state_list, state_entry) {
+		list_move(&st->state_entry, &head);
+	}
+	spin_unlock(&conn->state_lock);
+
+	list_for_each_entry_safe(st, stmp, &head, state_entry) {
+		list_del_init(&st->state_entry);
+		pohmelfs_state_kill(st);
+	}
+
+	if (!list_empty(&conn->reconnect_list) && !conn->need_exit)
+		queue_delayed_work(conn->wq, &conn->reconnect_work, conn->psb->reconnect_timeout);
+}
+
+void pohmelfs_pool_clean(struct pohmelfs_connection *conn, int conn_num)
+{
+	struct pohmelfs_connection *c;
+	struct pohmelfs_state *st, *tmp;
+	struct pohmelfs_reconnect *r, *rtmp;
+	int i;
+
+	if (!conn || !conn_num)
+		return;
+
+	for (i = 0; i < conn_num; ++i) {
+		c = &conn[i];
+
+		c->need_exit = 1;
+
+		cancel_delayed_work_sync(&c->reconnect_work);
+
+		list_for_each_entry_safe(st, tmp, &c->state_list, state_entry) {
+			list_del_init(&st->state_entry);
+
+			pohmelfs_state_kill(st);
+		}
+
+		list_for_each_entry_safe(st, tmp, &c->kill_state_list, state_entry) {
+			list_del_init(&st->state_entry);
+			pohmelfs_state_kill(st);
+		}
+
+		list_for_each_entry_safe(r, rtmp, &c->reconnect_list, reconnect_entry) {
+			list_del(&r->reconnect_entry);
+			kfree(r);
+		}
+
+		destroy_workqueue(c->wq);
+	}
+
+	kfree(conn);
+}
+
+int pohmelfs_pool_resize(struct pohmelfs_sb *psb, int num)
+{
+	int err = 0, old_conn_num, i;
+	struct pohmelfs_connection *conn, *old_conn, *c;
+	struct pohmelfs_addr *a;
+	char name[16];
+
+	conn = kzalloc(num * sizeof(struct pohmelfs_connection), GFP_NOIO);
+	if (!conn) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	for (i = 0; i < num; ++i) {
+		c = &conn[i];
+
+		c->psb = psb;
+		c->idx = i;
+
+		c->route_root = RB_ROOT;
+		spin_lock_init(&c->state_lock);
+		INIT_LIST_HEAD(&c->state_list);
+
+		INIT_LIST_HEAD(&c->kill_state_list);
+
+		mutex_init(&c->reconnect_lock);
+		INIT_LIST_HEAD(&c->reconnect_list);
+
+		INIT_DELAYED_WORK(&c->reconnect_work, pohmelfs_reconnect);
+
+		snprintf(name, sizeof(name), "pohmelfs-%d-%d", psb->bdi_num, i);
+		c->wq = alloc_workqueue(name, WQ_NON_REENTRANT | WQ_UNBOUND | WQ_FREEZABLE | WQ_MEM_RECLAIM, 0);
+		if (!c->wq) {
+			err = -ENOMEM;
+			old_conn = conn;
+			old_conn_num = i;
+			goto err_out_free;
+		}
+
+		mutex_lock(&psb->conn_lock);
+		list_for_each_entry(a, &psb->addr_list, addr_entry) {
+			pohmelfs_state_create(c, &a->sa, a->addrlen, 1, 0);
+		}
+		mutex_unlock(&psb->conn_lock);
+
+	}
+
+	mutex_lock(&psb->conn_lock);
+	old_conn = psb->conn;
+	old_conn_num = psb->conn_num;
+
+	psb->conn = conn;
+	psb->conn_num = num;
+
+	psb->meta_num = psb->conn_num / 8 + 1;
+	psb->bulk_num = psb->conn_num - psb->meta_num;
+
+	psb->meta_idx = 0;
+	psb->bulk_idx = 0;
+	mutex_unlock(&psb->conn_lock);
+	err = 0;
+
+err_out_free:
+	pohmelfs_pool_clean(old_conn, old_conn_num);
+err_out_exit:
+	return err;
+}
diff --git a/fs/pohmelfs/route.c b/fs/pohmelfs/route.c
new file mode 100644
index 0000000..d8592fb
--- /dev/null
+++ b/fs/pohmelfs/route.c
@@ -0,0 +1,366 @@
+/*
+ * Copyright (C) 2011+ Evgeniy Polyakov <zbr@xxxxxxxxxxx>
+ */
+
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+#include "pohmelfs.h"
+
+
+static inline int pohmelfs_route_cmp_raw(const struct pohmelfs_route *rt, const struct dnet_raw_id *raw, int group_id)
+{
+	if (rt->group_id < group_id)
+		return -1;
+	if (rt->group_id > group_id)
+		return 1;
+
+	return dnet_id_cmp_str(rt->id.id, raw->id);
+}
+
+static inline int pohmelfs_route_cmp(const struct pohmelfs_route *id1, const struct pohmelfs_route *id2)
+{
+	return pohmelfs_route_cmp_raw(id1, &id2->id, id2->group_id);
+}
+
+static int pohmelfs_route_insert(struct pohmelfs_connection *conn, struct pohmelfs_route *rt)
+{
+	struct rb_node **n = &conn->route_root.rb_node, *parent = NULL;
+	struct pohmelfs_route *tmp;
+	int cmp, err = 0;
+
+	spin_lock(&conn->state_lock);
+	while (*n) {
+		parent = *n;
+
+		tmp = rb_entry(parent, struct pohmelfs_route, node);
+
+		cmp = pohmelfs_route_cmp(tmp, rt);
+		if (cmp < 0)
+			n = &parent->rb_left;
+		else if (cmp > 0)
+			n = &parent->rb_right;
+		else {
+			err = -EEXIST;
+			goto err_out_unlock;
+		}
+	}
+
+	rb_link_node(&rt->node, parent, n);
+	rb_insert_color(&rt->node, &conn->route_root);
+
+err_out_unlock:
+	spin_unlock(&conn->state_lock);
+	return err;
+	
+}
+
+static int pohmelfs_route_add(struct pohmelfs_state *st, struct dnet_raw_id *id, int group_id)
+{
+	struct pohmelfs_connection *conn = st->conn;
+	struct pohmelfs_route *rt;
+	int err;
+
+	rt = kmem_cache_zalloc(pohmelfs_route_cache, GFP_NOIO);
+	if (!rt) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	memcpy(&rt->id, id, sizeof(struct dnet_raw_id));
+	rt->group_id = group_id;
+	rt->st = st;
+
+	pohmelfs_state_get(st);
+
+	err = pohmelfs_route_insert(conn, rt);
+	if (err)
+		goto err_out_put;
+
+	rt->st->routes++;
+	return 0;
+
+err_out_put:
+	pohmelfs_state_put(st);
+	kmem_cache_free(pohmelfs_route_cache, rt);
+err_out_exit:
+	return err;
+}
+
+static struct pohmelfs_state *pohmelfs_state_lookup_connection(struct pohmelfs_connection *conn, struct dnet_raw_id *id, int group_id)
+{
+	struct rb_node *n = conn->route_root.rb_node;
+	struct pohmelfs_route *rt;
+	struct pohmelfs_state *st = NULL;
+	int cmp;
+
+	spin_lock(&conn->state_lock);
+	while (n) {
+		rt = rb_entry(n, struct pohmelfs_route, node);
+
+		cmp = pohmelfs_route_cmp_raw(rt, id, group_id);
+
+		if (!st && (rt->group_id == group_id)) {
+			st = rt->st;
+		}
+
+		if (cmp < 0) {
+			n = n->rb_left;
+
+			if (rt->group_id == group_id) {
+				st = rt->st;
+			}
+		} else if (cmp > 0)
+			n = n->rb_right;
+		else {
+			st = rt->st;
+			break;
+		}
+	}
+	if (st)
+		pohmelfs_state_get(st);
+
+	spin_unlock(&conn->state_lock);
+
+	return st;
+}
+
+struct pohmelfs_state *pohmelfs_state_lookup(struct pohmelfs_sb *psb, struct dnet_raw_id *id, int group_id, ssize_t size)
+{
+	struct pohmelfs_state *st;
+	struct pohmelfs_connection *c;
+	int idx;
+
+	mutex_lock(&psb->conn_lock);
+	if ((size > PAGE_SIZE) || (size < 0)) {
+		idx = psb->bulk_idx;
+		if (++psb->bulk_idx >= psb->bulk_num)
+			psb->bulk_idx = 0;
+	} else {
+		/* meta connections are placed after bulk */
+		idx = psb->meta_idx + psb->bulk_num;
+		if (++psb->meta_idx >= psb->meta_num)
+			psb->meta_idx = 0;
+	}
+
+	pr_debug("pohmelfs: %s: selected connection: %d, group: %d, size: %zd\n", pohmelfs_dump_id(id->id), idx, group_id, size);
+
+	c = &psb->conn[idx];
+	st = pohmelfs_state_lookup_connection(c, id, group_id);
+	mutex_unlock(&psb->conn_lock);
+
+	return st;
+}
+
+int pohmelfs_grab_states(struct pohmelfs_sb *psb, struct pohmelfs_state ***stp)
+{
+	struct pohmelfs_state **states, *st;
+	struct pohmelfs_connection *c;
+	int err;
+	int num = 0, pos = 0;
+
+	mutex_lock(&psb->conn_lock);
+	c = &psb->conn[0];
+
+	spin_lock(&c->state_lock);
+	list_for_each_entry(st, &c->state_list, state_entry) {
+		++num;
+	}
+	spin_unlock(&c->state_lock);
+	mutex_unlock(&psb->conn_lock);
+
+	if (!num) {
+		err = -ENOENT;
+		goto err_out_exit;
+	}
+
+	states = kzalloc(sizeof(struct pohmelfs_state *) * num, GFP_NOIO);
+	if (!states) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	mutex_lock(&psb->conn_lock);
+	c = &psb->conn[0];
+
+	spin_lock(&c->state_lock);
+	list_for_each_entry(st, &c->state_list, state_entry) {
+		pohmelfs_state_get(st);
+		states[pos] = st;
+		++pos;
+	}
+	spin_unlock(&c->state_lock);
+	mutex_unlock(&psb->conn_lock);
+
+	*stp = states;
+	return pos;
+
+err_out_exit:
+	return err;
+}
+
+static void pohmelfs_route_remove_nolock(struct pohmelfs_connection *conn, struct pohmelfs_route *rt)
+{
+	rt->st->routes--;
+	rb_erase(&rt->node, &conn->route_root);
+	pohmelfs_state_put(rt->st);
+	kmem_cache_free(pohmelfs_route_cache, rt);
+}
+
+void pohmelfs_route_remove_all(struct pohmelfs_state *st)
+{
+	struct pohmelfs_connection *conn = st->conn;
+	struct pohmelfs_route *rt;
+	struct rb_node *n;
+	int again = 1;
+
+	while (again) {
+		spin_lock(&conn->state_lock);
+
+		n = rb_first(&conn->route_root);
+		if (!n) {
+			spin_unlock(&conn->state_lock);
+			break;
+		}
+
+		again = 0;
+		while (n) {
+			rt = rb_entry(n, struct pohmelfs_route, node);
+
+			if (rt->st == st) {
+				pohmelfs_route_remove_nolock(conn, rt);
+				again = 1;
+				break;
+			}
+
+			n = rb_next(n);
+		}
+		spin_unlock(&conn->state_lock);
+
+		cond_resched();
+	}
+}
+
+static int pohmelfs_route_request_complete(struct pohmelfs_trans *t, struct pohmelfs_state *recv)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(t->inode->i_sb);
+	struct dnet_cmd *cmd = &recv->cmd;
+	struct pohmelfs_state *st;
+	struct dnet_attr *attr;
+	struct dnet_addr_attr *a;
+	struct dnet_raw_id *ids;
+	int err = 0;
+
+	if (!t->io_offset)
+		goto err_out_exit;
+
+	attr = t->recv_data;
+	dnet_convert_attr(attr);
+
+	if (attr->size > sizeof(struct dnet_addr_attr)) {
+		int i, j, num = (attr->size - sizeof(struct dnet_addr_attr)) / sizeof(struct dnet_raw_id);
+
+		a = (struct dnet_addr_attr *)(attr + 1);
+		dnet_convert_addr_attr(a);
+		ids = (struct dnet_raw_id *)(a + 1);
+
+		mutex_lock(&psb->conn_lock);
+		for (j = 0; j < psb->conn_num; ++j) {
+			struct pohmelfs_connection *c = &psb->conn[j];
+
+			st = pohmelfs_state_create(c, (struct sockaddr_storage *)&a->addr.addr, a->addr.addr_len,
+					0, cmd->id.group_id);
+			if (IS_ERR(st)) {
+				err = PTR_ERR(st);
+
+				if (err == -EEXIST) {
+					spin_lock(&c->state_lock);
+					st = pohmelfs_addr_exist(c, (struct sockaddr_storage *)&a->addr.addr, a->addr.addr_len);
+					if (st) {
+						st->group_id = cmd->id.group_id;
+						pohmelfs_state_get(st);
+						err = 0;
+					}
+					spin_unlock(&c->state_lock);
+				}
+
+				if (err)
+					goto err_out_unlock;
+			} else {
+				/*
+				 * reference grab logic should be the same
+				 * as in case when state exist - we will drop
+				 * it at the end, so we would not check whether
+				 * it is new state (and refcnt == 1) or
+				 * existing (refcnt > 1)
+				 */
+				pohmelfs_state_get(st);
+			}
+
+			for (i = 0; i < num; ++i) {
+				dnet_convert_raw_id(&ids[i]);
+#if 0
+				pohmelfs_print_addr((struct sockaddr_storage *)&a->addr.addr, "%d:%s\n",
+						cmd->id.group_id, pohmelfs_dump_id(ids[i].id));
+#endif
+
+				err = pohmelfs_route_add(st, &ids[i], cmd->id.group_id);
+				if (err) {
+					if (err != -EEXIST) {
+						/* remove this state from route table */
+						spin_lock(&c->state_lock);
+						list_del_init(&st->state_entry);
+						spin_unlock(&c->state_lock);
+
+						/* drop abovementioned refcnt */
+						pohmelfs_state_put(st);
+
+						pohmelfs_state_kill(st);
+						goto err_out_exit;
+					}
+
+					err = 0;
+				}
+			}
+
+			/* drop abovementioned refcnt */
+			pohmelfs_state_put(st);
+		}
+err_out_unlock:
+		mutex_unlock(&psb->conn_lock);
+	}
+
+err_out_exit:
+	return err;
+}
+
+int pohmelfs_route_request(struct pohmelfs_state *st)
+{
+	struct pohmelfs_sb *psb = st->conn->psb;
+	struct pohmelfs_io *pio;
+	int err;
+
+	pio = kmem_cache_zalloc(pohmelfs_io_cache, GFP_NOIO);
+	if (!pio) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	pio->pi = psb->root;
+	pio->id = &psb->root->id;
+	pio->cmd = DNET_CMD_ROUTE_LIST;
+	pio->cflags = DNET_FLAGS_DIRECT | DNET_FLAGS_NEED_ACK;
+	pio->cb.complete = pohmelfs_route_request_complete;
+
+	err = pohmelfs_send_buf_single(pio, st);
+	if (err) {
+		pohmelfs_print_addr(&st->sa, "pohmelfs: pohmelfs_route_request: %d\n", err);
+		goto err_out_free;
+	}
+	pohmelfs_print_addr(&st->sa, "route request sent\n");
+
+err_out_free:
+	kmem_cache_free(pohmelfs_io_cache, pio);
+err_out_exit:
+	return err;
+}
diff --git a/fs/pohmelfs/stat.c b/fs/pohmelfs/stat.c
new file mode 100644
index 0000000..bf13d03
--- /dev/null
+++ b/fs/pohmelfs/stat.c
@@ -0,0 +1,139 @@
+/*
+ * Copyright (C) 2011+ Evgeniy Polyakov <zbr@xxxxxxxxxxx>
+ */
+
+#include "pohmelfs.h"
+
+static int pohmelfs_stat_init(struct pohmelfs_trans *t)
+{
+	struct pohmelfs_wait *wait = t->priv;
+
+	atomic_long_inc(&wait->count);
+	pohmelfs_wait_get(wait);
+	return 0;
+}
+
+static void pohmelfs_stat_destroy(struct pohmelfs_trans *t)
+{
+	struct pohmelfs_wait *wait = t->priv;
+
+	atomic_long_dec(&wait->count);
+	wake_up(&wait->wq);
+	pohmelfs_wait_put(wait);
+}
+
+static int pohmelfs_stat_complete(struct pohmelfs_trans *t, struct pohmelfs_state *recv)
+{
+	struct pohmelfs_wait *wait = t->priv;
+	struct dnet_cmd *cmd = &recv->cmd;
+	struct dnet_attr *attr;
+	int err = cmd->status;
+
+	if (err)
+		goto err_out_exit;
+
+	if (cmd->size != sizeof(struct dnet_attr) + sizeof(struct dnet_stat)) {
+		err = -ENOENT;
+		goto err_out_exit;
+	}
+
+	attr = t->recv_data;
+
+	if ((cmd->flags & DNET_FLAGS_MORE) && (attr->cmd == DNET_CMD_STAT) && (attr->size == sizeof(struct dnet_stat))) {
+		struct dnet_stat *stat;
+
+		stat = t->recv_data + sizeof(struct dnet_attr);
+		dnet_convert_stat(stat);
+
+		recv->bsize = stat->bsize;
+		recv->frsize = stat->frsize;
+		recv->blocks = stat->blocks;
+		recv->bfree = stat->bfree;
+		recv->bavail = stat->bavail;
+
+		pr_debug("pohmelfs: %s: pohmelfs_stat_complete: total: %llu, avail: %llu\n",
+				pohmelfs_dump_id(cmd->id.id), 
+				(unsigned long long)(stat->frsize * stat->blocks / 1024 / 1024),
+				(unsigned long long)(stat->bavail * stat->bsize / 1024 / 1024));
+	}
+
+err_out_exit:
+	if (err)
+		wait->condition = err;
+	else
+		wait->condition = 1;
+	wake_up(&wait->wq);
+
+	return 0;
+}
+
+int pohmelfs_stat(struct pohmelfs_sb *psb, int sync)
+{
+	struct pohmelfs_state **states, *st;
+	struct pohmelfs_wait *wait;
+	struct pohmelfs_io *pio;
+	int err, i, num;
+	long ret;
+
+	wait = pohmelfs_wait_alloc(psb->root);
+	if (!wait) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	pio = kmem_cache_zalloc(pohmelfs_io_cache, GFP_NOIO);
+	if (!pio) {
+		err = -ENOMEM;
+		goto err_out_put;
+	}
+
+	err = pohmelfs_grab_states(psb, &states);
+	if (err < 0)
+		goto err_out_free_pio;
+
+	pio->pi = psb->root;
+	/* we use state pointer, but do not know correct ID, so use DIRECT flag here to forbid request forwarding */
+	pio->cflags = DNET_FLAGS_NEED_ACK | DNET_FLAGS_NOLOCK | DNET_FLAGS_DIRECT;
+	pio->cmd = DNET_CMD_STAT;
+	pio->priv = wait;
+	pio->cb.init = pohmelfs_stat_init;
+	pio->cb.destroy = pohmelfs_stat_destroy;
+	pio->cb.complete = pohmelfs_stat_complete;
+
+	num = err;
+	for (i = 0; i < num; ++i) {
+		st = states[i];
+
+		pio->group_id = st->group_id;
+		pio->id = &psb->root->id;
+
+		err = pohmelfs_send_buf_single(pio, st);
+		pohmelfs_state_put(st);
+	}
+
+	err = 0;
+
+	if (sync) {
+		ret = wait_event_interruptible_timeout(wait->wq,
+				atomic_long_read(&wait->count) != 0,
+				msecs_to_jiffies(psb->read_wait_timeout));
+		if (ret <= 0) {
+			err = ret;
+			if (ret == 0)
+				err = -ETIMEDOUT;
+			goto err_out_free;
+		}
+
+		if (wait->condition < 0)
+			err = wait->condition;
+	}
+
+err_out_free:
+	kfree(states);
+err_out_free_pio:
+	kmem_cache_free(pohmelfs_io_cache, pio);
+err_out_put:
+	pohmelfs_wait_put(wait);
+err_out_exit:
+	return err;
+}
diff --git a/fs/pohmelfs/super.c b/fs/pohmelfs/super.c
new file mode 100644
index 0000000..514a139
--- /dev/null
+++ b/fs/pohmelfs/super.c
@@ -0,0 +1,977 @@
+/*
+ * Copyright (C) 2011+ Evgeniy Polyakov <zbr@xxxxxxxxxxx>
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/inet.h>
+#include <linux/init.h>
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <linux/blkdev.h>
+#include <linux/parser.h>
+#include <linux/random.h>
+#include <linux/buffer_head.h>
+#include <linux/exportfs.h>
+#include <linux/vfs.h>
+#include <linux/seq_file.h>
+#include <linux/mount.h>
+#include <linux/quotaops.h>
+#include <asm/uaccess.h>
+
+#include "pohmelfs.h"
+
+#define POHMELFS_MAGIC_NUM	0x504f482e
+
+struct kmem_cache *pohmelfs_inode_cache;
+struct kmem_cache *pohmelfs_trans_cache;
+struct kmem_cache *pohmelfs_inode_info_cache;
+struct kmem_cache *pohmelfs_route_cache;
+struct kmem_cache *pohmelfs_wait_cache;
+struct kmem_cache *pohmelfs_io_cache;
+struct kmem_cache *pohmelfs_inode_info_binary_package_cache;
+struct kmem_cache *pohmelfs_write_cache;
+struct kmem_cache *pohmelfs_dentry_cache;
+
+static atomic_t psb_bdi_num = ATOMIC_INIT(0);
+
+static void pohmelfs_http_compat_cleanup(struct pohmelfs_sb *psb)
+{
+	struct pohmelfs_path *p;
+	int i;
+
+	for (i = 0; i < psb->http_compat; ++i) {
+		p = &psb->path[i];
+
+		mutex_destroy(&p->lock);
+		kfree(p->data);
+	}
+}
+
+static int pohmelfs_http_compat_init(struct pohmelfs_sb *psb)
+{
+	int i, err;
+	struct pohmelfs_path *path, *p;
+
+	path = kmalloc(psb->http_compat * sizeof(struct pohmelfs_path), GFP_KERNEL);
+	if (!path) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	for (i = 0; i < psb->http_compat; ++i) {
+		p = &path[i];
+
+		mutex_init(&p->lock);
+
+		p->data = kmalloc(PAGE_SIZE, GFP_KERNEL);
+		if (!p->data) {
+			err = -ENOMEM;
+			goto err_out_free;
+		}
+	}
+
+	psb->path = path;
+	return 0;
+
+err_out_free:
+	while (--i >= 0) {
+		p = &path[i];
+
+		mutex_destroy(&p->lock);
+		kfree(p->data);
+	}
+
+	kfree(path);
+err_out_exit:
+	psb->http_compat = 0;
+	return err;
+}
+
+static void pohmelfs_cleanup_psb(struct pohmelfs_sb *psb)
+{
+	struct pohmelfs_addr *a, *tmp;
+
+	psb->need_exit = 1;
+	cancel_delayed_work(&psb->sync_work);
+	destroy_workqueue(psb->wq);
+
+	pohmelfs_pool_clean(psb->conn, psb->conn_num);
+
+	list_for_each_entry_safe(a, tmp, &psb->addr_list, addr_entry) {
+		list_del(&a->addr_entry);
+		kfree(a);
+	}
+
+	crypto_free_hash(psb->hash);
+
+	pohmelfs_http_compat_cleanup(psb);
+
+	kfree(psb->groups);
+	kfree(psb->fsid);
+}
+
+static void pohmelfs_put_super(struct super_block *sb)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(sb);
+
+	pohmelfs_cleanup_psb(psb);
+	bdi_destroy(&psb->bdi);
+}
+
+struct pohmelfs_size {
+	int			group_id;
+	uint64_t		bsize;		/* Block size */
+	uint64_t		frsize;		/* Fragment size */
+	uint64_t		blocks;		/* Filesystem size in frsize units */
+	uint64_t		bfree;		/* # free blocks */
+	uint64_t		bavail;		/* # free blocks for non-root */
+};
+
+static int pohmelfs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct super_block *sb = dentry->d_sb;
+	struct pohmelfs_sb *psb = pohmelfs_sb(sb);
+	struct pohmelfs_connection *c;
+	struct pohmelfs_state *st;
+	struct pohmelfs_size *sz;
+	uint64_t min_size = ~0ULL;
+	int pos = -1;
+	int err, i;
+
+	sz = kzalloc(psb->group_num * sizeof(struct pohmelfs_size), GFP_KERNEL);
+	if (!sz) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	for (i = 0; i < psb->group_num; ++i) {
+		sz[i].group_id = psb->groups[i];
+	}
+
+	memset(buf, 0, sizeof(struct kstatfs));
+
+	buf->f_type = POHMELFS_MAGIC_NUM; /* 'POH.' */
+	buf->f_namelen = 4096;
+	buf->f_files = 0;
+	buf->f_bfree = buf->f_bavail = buf->f_blocks = 0;
+
+	mutex_lock(&psb->conn_lock);
+	c = &psb->conn[0];
+
+	spin_lock(&c->state_lock);
+	list_for_each_entry(st, &c->state_list, state_entry) {
+		for (i = 0; i < psb->group_num; ++i) {
+			if (sz[i].group_id == st->group_id) {
+				sz[i].bsize = sb->s_blocksize;
+				sz[i].frsize = st->frsize;
+				sz[i].blocks += (st->blocks * st->frsize) >> PAGE_SHIFT;
+				sz[i].bfree += (st->bfree * st->bsize) >> PAGE_SHIFT;
+				sz[i].bavail += (st->bavail * st->bsize) >> PAGE_SHIFT;
+				break;
+			}
+		}
+
+
+	}
+	spin_unlock(&c->state_lock);
+	mutex_unlock(&psb->conn_lock);
+
+	for (i = 0; i < psb->group_num; ++i) {
+		/* skip empty groups */
+		if (sz[i].blocks && (sz[i].bavail < min_size)) {
+			min_size = sz[i].bavail;
+			pos = i;
+		}
+	}
+
+	if (pos == -1) {
+		buf->f_bfree = buf->f_bavail = buf->f_blocks = ~0ULL >> PAGE_SHIFT;
+	} else {
+		buf->f_bsize = sz[pos].bsize;
+		buf->f_frsize = sz[pos].frsize;
+		buf->f_blocks = sz[pos].blocks;
+		buf->f_bavail = sz[pos].bfree;
+		buf->f_bfree = sz[pos].bavail;
+	}
+
+	kfree(sz);
+	err = 0;
+
+err_out_exit:
+	return err;
+}
+
+#if 0
+static int pohmelfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(vfs->mnt_sb);
+#else
+static int pohmelfs_show_options(struct seq_file *seq, struct dentry *dentry)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(dentry->d_inode->i_sb);
+#endif
+	struct pohmelfs_addr *a;
+
+	mutex_lock(&psb->conn_lock);
+	list_for_each_entry(a, &psb->addr_list, addr_entry) {
+		struct sockaddr *sa = (struct sockaddr *)&a->sa;
+		if (sa->sa_family == AF_INET) {
+			struct sockaddr_in *sin = (struct sockaddr_in *)sa;
+			seq_printf(seq, ",server=%pI4:%d:2", &sin->sin_addr.s_addr, ntohs(sin->sin_port));
+		} else if (sa->sa_family == AF_INET6) {
+			struct sockaddr_in6 *sin = (struct sockaddr_in6 *)sa;
+			seq_printf(seq, ",server=%pI6:%d:6", &sin->sin6_addr.s6_addr, ntohs(sin->sin6_port));
+		}
+	}
+	mutex_unlock(&psb->conn_lock);
+
+	if (psb->no_read_csum)
+		seq_printf(seq, ",noreadcsum");
+	seq_printf(seq, ",sync_timeout=%ld", psb->sync_timeout);
+	if (psb->fsid)
+		seq_printf(seq, ",fsid=%s", psb->fsid);
+	if (psb->successful_write_count)
+		seq_printf(seq, ",successful_write_count=%d", psb->successful_write_count);
+	seq_printf(seq, ",keepalive_cnt=%d", psb->keepalive_cnt);
+	seq_printf(seq, ",keepalive_interval=%d", psb->keepalive_interval);
+	seq_printf(seq, ",keepalive_idle=%d", psb->keepalive_idle);
+	seq_printf(seq, ",readdir_allocation=%d", psb->readdir_allocation);
+	if (psb->http_compat)
+		seq_printf(seq, ",http_compat=%d", psb->http_compat);
+	if (psb->sync_on_close)
+		seq_printf(seq, ",sync_on_close");
+	seq_printf(seq, ",connection_pool_size=%d", psb->conn_num);
+	seq_printf(seq, ",read_wait_timeout=%ld", psb->read_wait_timeout);
+	seq_printf(seq, ",write_wait_timeout=%ld", psb->write_wait_timeout);
+	return 0;
+}
+
+/*
+ * This is tricky function - inode cache can be shrunk and inode is about to be dropped,
+ * since its last reference is dropped. But then icache can __iget() on this inode and
+ * later iput() it, which will again call ->drop_inode() callback.
+ *
+ * So, ->drop_inode() can be called multiple times for single inode without its reintialization
+ * And we better to be ready for this
+ */
+static int pohmelfs_drop_inode(struct inode *inode)
+{
+	struct pohmelfs_inode *pi = pohmelfs_inode(inode);
+	struct pohmelfs_sb *psb = pohmelfs_sb(inode->i_sb);
+
+	pr_debug("pohmelfs: %s: drop ino: %ld, mapping: %p\n", pohmelfs_dump_id(pi->id.id), inode->i_ino, inode->i_mapping);
+
+	spin_lock(&psb->inode_lock);
+	if (rb_parent(&pi->node) != &pi->node)
+		rb_erase(&pi->node, &psb->inode_root);
+	rb_init_node(&pi->node);
+	spin_unlock(&psb->inode_lock);
+
+	return generic_drop_inode(inode);
+}
+
+static int pohmelfs_write_inode_complete(struct pohmelfs_trans *t, struct pohmelfs_state *recv)
+{
+	struct dnet_cmd *cmd = &recv->cmd;
+	struct pohmelfs_inode_info_binary_package *bin = t->priv;
+	struct pohmelfs_wait *wait = &bin->wait;
+
+	if (cmd->flags & DNET_FLAGS_MORE)
+		return 0;
+
+	wait->condition = cmd->status;
+	if (!wait->condition)
+		wait->condition = 1;
+	wake_up(&wait->wq);
+
+	return 0;
+}
+
+static int pohmelfs_write_inode_init(struct pohmelfs_trans *t)
+{
+	struct pohmelfs_inode_info_binary_package *bin = t->priv;
+
+	kref_get(&bin->wait.refcnt);
+	return 0;
+}
+
+static void pohmelfs_write_inode_release(struct kref *kref)
+{
+	struct pohmelfs_wait *wait = container_of(kref, struct pohmelfs_wait, refcnt);
+	struct pohmelfs_inode_info_binary_package *bin = container_of(wait, struct pohmelfs_inode_info_binary_package, wait);
+
+	iput(&bin->wait.pi->vfs_inode);
+	kmem_cache_free(pohmelfs_inode_info_binary_package_cache, bin);
+}
+
+static void pohmelfs_write_inode_destroy(struct pohmelfs_trans *t)
+{
+	struct pohmelfs_inode_info_binary_package *bin = t->priv;
+
+	/*
+	 * We own this pointer - it points to &bin->info
+	 * Zero it here to prevent pohmelfs_trans_release() from freeing it
+	 */
+	t->data = NULL;
+	
+	kref_put(&bin->wait.refcnt, pohmelfs_write_inode_release);
+}
+
+static int pohmelfs_write_inode(struct inode *inode, struct writeback_control *wbc)
+{
+	struct pohmelfs_inode *pi = pohmelfs_inode(inode);
+	struct pohmelfs_inode_info_binary_package *bin;
+	struct pohmelfs_sb *psb = pohmelfs_sb(inode->i_sb);
+	struct pohmelfs_io *pio;
+	int sync = 0;
+	long ret;
+	int err;
+
+	if (wbc)
+		sync = wbc->sync_mode == WB_SYNC_ALL;
+
+	pio = kmem_cache_zalloc(pohmelfs_io_cache, GFP_NOIO);
+	if (!pio) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	bin = kmem_cache_zalloc(pohmelfs_inode_info_binary_package_cache, GFP_NOIO);
+	if (!bin) {
+		err = -ENOMEM;
+		goto err_out_free_pio;
+	}
+
+	pohmelfs_fill_inode_info(inode, &bin->info);
+	err = pohmelfs_wait_init(&bin->wait, pi);
+	if (err)
+		goto err_out_put_bin;
+
+	pio->pi = pi;
+	pio->id = &pi->id;
+	pio->cmd = DNET_CMD_WRITE;
+	pio->offset = 0;
+	pio->size = sizeof(struct pohmelfs_inode_info);
+	pio->cflags = DNET_FLAGS_NEED_ACK;
+	pio->priv = bin;
+	pio->type = POHMELFS_INODE_COLUMN;
+
+	pio->data = &bin->info;
+	pio->alloc_flags = POHMELFS_IO_OWN;
+
+	pio->cb.complete = pohmelfs_write_inode_complete;
+	pio->cb.init = pohmelfs_write_inode_init;
+	pio->cb.destroy = pohmelfs_write_inode_destroy;
+
+	err = pohmelfs_send_io(pio);
+	if (err)
+		goto err_out_put_bin;
+
+	if (sync) {
+		struct pohmelfs_wait *wait = &bin->wait;
+
+		ret = wait_event_interruptible_timeout(wait->wq,
+				wait->condition != 0 && atomic_read(&wait->refcnt.refcount) <= 2,
+				msecs_to_jiffies(psb->write_wait_timeout));
+		if (ret <= 0) {
+			err = ret;
+			if (ret == 0)
+				err = -ETIMEDOUT;
+			goto err_out_put_bin;
+		}
+
+		if (wait->condition < 0) {
+			err = wait->condition;
+			goto err_out_put_bin;
+		}
+	}
+
+err_out_put_bin:
+	kref_put(&bin->wait.refcnt, pohmelfs_write_inode_release);
+err_out_free_pio:
+	kmem_cache_free(pohmelfs_io_cache, pio);
+err_out_exit:
+	return err;
+}
+
+static int pohmelfs_parse_options(struct pohmelfs_sb *psb, char *data);
+
+static int pohmelfs_remount_fs(struct super_block *sb, int *flags, char *data)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(sb);
+
+	return pohmelfs_parse_options(psb, data);
+}
+
+static const struct super_operations pohmelfs_sb_ops = {
+	.alloc_inode	= pohmelfs_alloc_inode,
+	.destroy_inode	= pohmelfs_destroy_inode,
+	.drop_inode	= pohmelfs_drop_inode,
+	.write_inode	= pohmelfs_write_inode,
+	.put_super	= pohmelfs_put_super,
+	.show_options   = pohmelfs_show_options,
+	.statfs		= pohmelfs_statfs,
+	.remount_fs	= pohmelfs_remount_fs,
+};
+
+static void pohmelfs_sync(struct work_struct *work)
+{
+	struct pohmelfs_sb *psb = container_of(to_delayed_work(work), struct pohmelfs_sb, sync_work);
+	struct super_block *sb = psb->sb;
+	long timeout = msecs_to_jiffies(psb->sync_timeout * 1000);
+
+	if (down_read_trylock(&sb->s_umount)) {
+		sync_filesystem(sb);
+		up_read(&sb->s_umount);
+
+		pohmelfs_stat(psb, 0);
+	} else {
+		timeout = 0;
+	}
+
+	if (!psb->need_exit)
+		queue_delayed_work(psb->wq, &psb->sync_work, timeout);
+}
+
+static int pohmelfs_init_psb(struct pohmelfs_sb *psb, struct super_block *sb)
+{
+	char name[16];
+	int err;
+
+	psb->inode_root = RB_ROOT;
+	spin_lock_init(&psb->inode_lock);
+
+	atomic_long_set(&psb->ino, 0);
+	atomic_long_set(&psb->trans, 0);
+
+	sb->s_fs_info = psb;
+	sb->s_op = &pohmelfs_sb_ops;
+	sb->s_magic = POHMELFS_MAGIC_NUM;
+	sb->s_maxbytes = MAX_LFS_FILESIZE;
+	sb->s_blocksize = PAGE_SIZE;
+	sb->s_bdi = &psb->bdi;
+	sb->s_time_gran = 0;
+
+	psb->read_wait_timeout = 5000;
+	psb->write_wait_timeout = 5000;
+
+	psb->sync_timeout = 300;
+
+	psb->keepalive_cnt = 5;
+	psb->keepalive_interval = 10;
+	psb->keepalive_idle = 30;
+
+	psb->readdir_allocation = 4;
+	psb->reconnect_timeout = msecs_to_jiffies(30000);
+
+	psb->conn_num = 5;
+
+	psb->sb = sb;
+
+	psb->hash = crypto_alloc_hash("sha512", 0, CRYPTO_ALG_ASYNC);
+	if (IS_ERR(psb->hash)) {
+		err = PTR_ERR(psb->hash);
+		goto err_out_exit;
+	}
+
+	snprintf(name, sizeof(name), "pohmelfs-sync-%d", psb->bdi_num);
+	psb->wq = alloc_workqueue(name, WQ_NON_REENTRANT | WQ_UNBOUND | WQ_FREEZABLE | WQ_MEM_RECLAIM, 0);
+	if (!psb->wq) {
+		err = -ENOMEM;
+		goto err_out_crypto_free;
+	}
+
+	mutex_init(&psb->conn_lock);
+	INIT_LIST_HEAD(&psb->addr_list);
+
+	INIT_DELAYED_WORK(&psb->sync_work, pohmelfs_sync);
+
+	return 0;
+
+err_out_crypto_free:
+	crypto_free_hash(psb->hash);
+err_out_exit:
+	psb->sb = NULL;
+	sb->s_fs_info = NULL;
+	return err;
+}
+
+static int pohmelfs_parse_addr(char *addr, struct sockaddr_storage *a, int *addrlen)
+{
+	int family, port;
+	char *ptr;
+	int err = -EINVAL;
+
+	ptr = strrchr(addr, ':');
+	if (!ptr)
+		goto err_out_print_wrong_param;
+	*ptr++ = 0;
+	if (!ptr)
+		goto err_out_print_wrong_param;
+
+	family = simple_strtol(ptr, NULL, 10);
+
+	ptr = strrchr(addr, ':');
+	if (!ptr)
+		goto err_out_print_wrong_param;
+	*ptr++ = 0;
+	if (!ptr)
+		goto err_out_print_wrong_param;
+
+	port = simple_strtol(ptr, NULL, 10);
+
+	if (family == AF_INET) {
+		struct sockaddr_in *sin = (struct sockaddr_in *)a;
+
+		sin->sin_family = family;
+		sin->sin_port = htons(port);
+
+		err = in4_pton(addr, strlen(addr), (u8 *)&sin->sin_addr, ':', NULL);
+		*addrlen = sizeof(struct sockaddr_in);
+	} else if (family == AF_INET6) {
+		struct sockaddr_in6 *sin = (struct sockaddr_in6 *)a;
+
+		sin->sin6_family = family;
+		sin->sin6_port = htons(port);
+		err = in6_pton(addr, strlen(addr), (u8 *)&sin->sin6_addr, ':', NULL);
+		*addrlen = sizeof(struct sockaddr_in6);
+	} else {
+		err = -ENOTSUPP;
+	}
+
+	if (err == 1)
+		err = 0;
+	else if (!err)
+		err = -EINVAL;
+
+	if (err)
+		goto err_out_print_wrong_param;
+
+	return 0;
+
+err_out_print_wrong_param:
+	pr_err("pohmelfs: %s: wrong addr: '%s', should be 'addr:port:family': %d.\n", __func__, addr, err);
+	return err;
+}
+
+static int pohmelfs_option(char *option, char *data, int *lenp, int have_data)
+{
+	int len;
+	char *ptr;
+
+	if (!strncmp(option, data, strlen(option))) {
+		len = strlen(option);
+		ptr = data + len;
+
+		if (have_data && (!ptr || !*ptr))
+			return 0;
+
+		*lenp = len;
+		return 1;
+	}
+
+	return 0;
+}
+
+static int pohmelfs_set_groups(struct pohmelfs_sb *psb, char *value, int len)
+{
+	int i, num = 0, start = 0, pos = 0;
+	char *ptr = value;
+
+	for (i = 0; i < len; ++i) {
+		if (value[i] == ':')
+			start = 0;
+		else if (!start) {
+			start = 1;
+			num++;
+		}
+	}
+
+	if (!num) {
+		return -ENOENT;
+	}
+
+	/*
+	 * We do not allow to mess with different group sets for already built filesystem
+	 * But to prevent remount from failing, we just pretend that things went the right way
+	 */
+	if (psb->groups)
+		return 0;
+
+	psb->groups = kzalloc(sizeof(int) * num, GFP_KERNEL);
+	if (!psb->groups)
+		return -ENOMEM;
+	psb->group_num = num;
+
+	start = 0;
+	for (i = 0; i < len; ++i) {
+		if (value[i] == ':') {
+			value[i] = '\0';
+			if (start) {
+				psb->groups[pos] = simple_strtol(ptr, NULL, 10);
+				pos++;
+				start = 0;
+			}
+		} else if (!start) {
+			ptr = &value[i];
+			start = 1;
+		}
+	}
+
+	if (start) {
+		psb->groups[pos] = simple_strtol(ptr, NULL, 10);
+		pos++;
+	}
+
+	return 0;
+}
+
+static int pohmelfs_parse_option(struct pohmelfs_sb *psb, char *data)
+{
+	int len;
+	int err = 0;
+
+	pr_debug("pohmelfs: %s: option: %s\n", __func__, data);
+
+	if (pohmelfs_option("server=", data, &len, 1)) {
+		struct pohmelfs_addr *a, *tmp;
+		char *addr_str = data + len;
+
+		a = kzalloc(sizeof(struct pohmelfs_addr), GFP_KERNEL);
+		if (!a) {
+			err = -ENOMEM;
+			goto err_out_exit;
+		}
+
+		err = pohmelfs_parse_addr(addr_str, &a->sa, &a->addrlen);
+		if (err)
+			goto err_out_exit;
+
+		mutex_lock(&psb->conn_lock);
+		list_for_each_entry(tmp, &psb->addr_list, addr_entry) {
+			if (tmp->addrlen != a->addrlen)
+				continue;
+
+			if (!memcmp(&tmp->sa, &a->sa, a->addrlen)) {
+				err = -EEXIST;
+				break;
+			}
+		}
+
+		if (!err)
+			list_add_tail(&a->addr_entry, &psb->addr_list);
+		else
+			kfree(a);
+		mutex_unlock(&psb->conn_lock);
+		err = 0;
+	} else if (pohmelfs_option("fsid=", data, &len, 1)) {
+		data += len;
+		len = strlen(data);
+
+		psb->fsid = kmalloc(len + 1, GFP_KERNEL);
+		if (!psb->fsid) {
+			err = -ENOMEM;
+			goto err_out_exit;
+		}
+
+		snprintf(psb->fsid, len + 1, "%s", data);
+		psb->fsid_len = len;
+	} else if (pohmelfs_option("sync_timeout=", data, &len, 1)) {
+		psb->sync_timeout = simple_strtol(data + len, NULL, 10);
+	} else if (pohmelfs_option("http_compat=", data, &len, 1)) {
+		psb->http_compat = simple_strtol(data + len, NULL, 10);
+		err = pohmelfs_http_compat_init(psb);
+	} else if (pohmelfs_option("groups=", data, &len, 1)) {
+		data += len;
+		len = strlen(data);
+
+		err = pohmelfs_set_groups(psb, data, len);
+	} else if (pohmelfs_option("noatime", data, &len, 0)) {
+		psb->sb->s_flags |= FS_NOATIME_FL;
+	} else if (pohmelfs_option("relatime", data, &len, 0)) {
+		psb->sb->s_flags |= MS_RELATIME;
+	} else if (pohmelfs_option("noreadcsum", data, &len, 0)) {
+		psb->no_read_csum = 1;
+	} else if (pohmelfs_option("readcsum", data, &len, 0)) {
+		psb->no_read_csum = 0;
+	} else if (pohmelfs_option("successful_write_count=", data, &len, 1)) {
+		psb->successful_write_count = simple_strtol(data + len, NULL, 10);
+	} else if (pohmelfs_option("keepalive_cnt=", data, &len, 1)) {
+		psb->keepalive_cnt = simple_strtol(data + len, NULL, 10);
+	} else if (pohmelfs_option("keepalive_idle=", data, &len, 1)) {
+		psb->keepalive_idle = simple_strtol(data + len, NULL, 10);
+	} else if (pohmelfs_option("keepalive_interval=", data, &len, 1)) {
+		psb->keepalive_interval = simple_strtol(data + len, NULL, 10);
+	} else if (pohmelfs_option("readdir_allocation=", data, &len, 1)) {
+		psb->readdir_allocation = simple_strtol(data + len, NULL, 10);
+	} else if (pohmelfs_option("sync_on_close", data, &len, 0)) {
+		psb->sync_on_close = 1;
+	} else if (pohmelfs_option("connection_pool_size=", data, &len, 1)) {
+		psb->conn_num = simple_strtol(data + len, NULL, 10);
+		if (psb->conn_num < 2)
+			psb->conn_num = 2;
+	} else if (pohmelfs_option("read_wait_timeout=", data, &len, 1)) {
+		psb->read_wait_timeout = simple_strtol(data + len, NULL, 10);
+	} else if (pohmelfs_option("write_wait_timeout=", data, &len, 1)) {
+		psb->write_wait_timeout = simple_strtol(data + len, NULL, 10);
+	} else {
+		err = -ENOTSUPP;
+	}
+
+err_out_exit:
+	return err;
+}
+
+static int pohmelfs_parse_options(struct pohmelfs_sb *psb, char *data)
+{
+	int err = -ENOENT;
+	char *ptr, *start;
+
+	ptr = start = data;
+
+	while (ptr && *ptr) {
+		if (*ptr == ',') {
+			*ptr = '\0';
+			err = pohmelfs_parse_option(psb, start);
+			if (err)
+				goto err_out_exit;
+			ptr++;
+			if (ptr && *ptr)
+				start = ptr;
+
+			continue;
+		}
+
+		ptr++;
+	}
+
+	if (start != ptr) {
+		err = pohmelfs_parse_option(psb, start);
+		if (err)
+			goto err_out_exit;
+	}
+
+err_out_exit:
+	return err;
+}
+
+static int pohmelfs_fill_super(struct super_block *sb, void *data, int silent)
+{
+	struct pohmelfs_sb *psb;
+	int err;
+
+	psb = kzalloc(sizeof(struct pohmelfs_sb), GFP_KERNEL);
+	if (!psb) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	psb->bdi_num = atomic_inc_return(&psb_bdi_num);
+
+	err = bdi_init(&psb->bdi);
+	if (err)
+		goto err_out_free_psb;
+
+	psb->bdi.ra_pages = default_backing_dev_info.ra_pages;
+
+	err = bdi_register(&psb->bdi, NULL, "pfs-%d", psb->bdi_num);
+	if (err) {
+		bdi_destroy(&psb->bdi);
+		goto err_out_free_psb;
+	}
+
+	err = pohmelfs_init_psb(psb, sb);
+	if (err)
+		goto err_out_free_bdi;
+
+	psb->root = pohmelfs_new_inode(psb, 0755|S_IFDIR);
+	if (IS_ERR(psb->root)) {
+		err = PTR_ERR(psb->root);
+		goto err_out_cleanup_psb;
+	}
+
+	err = pohmelfs_parse_options(psb, data);
+	if (err)
+		goto err_out_put_root;
+
+	if (!psb->group_num || list_empty(&psb->addr_list)) {
+		err = -EINVAL;
+		pr_err("pohmelfs: you have to specify number of groups and add remote node address (at least one)\n");
+		goto err_out_put_root;
+	}
+
+	if (!psb->fsid_len) {
+		char str[] = "pohmelfs";
+		err = pohmelfs_hash(psb, str, 8, &psb->root->id);
+	} else {
+		err = pohmelfs_hash(psb, psb->fsid, psb->fsid_len, &psb->root->id);
+	}
+	if (err)
+		goto err_out_put_root;
+
+	err = psb->conn_num;
+	psb->conn_num = 0;
+	err = pohmelfs_pool_resize(psb, err);
+	if (err)
+		goto err_out_put_root;
+
+	sb->s_root = d_make_root(&psb->root->vfs_inode);
+	if (!sb->s_root) {
+		err = -ENOMEM;
+		goto err_out_cleanup_psb;
+	}
+
+	queue_delayed_work(psb->wq, &psb->sync_work, msecs_to_jiffies(psb->sync_timeout * 1000));
+	pohmelfs_stat(psb, 0);
+
+	return 0;
+
+err_out_put_root:
+	iput(&psb->root->vfs_inode);
+err_out_cleanup_psb:
+	pohmelfs_cleanup_psb(psb);
+err_out_free_bdi:
+	bdi_destroy(&psb->bdi);
+err_out_free_psb:
+	kfree(psb);
+err_out_exit:
+	pr_err("pohmelfs: %s: error: %d\n", __func__, err);
+	return err;
+}
+
+static struct dentry *pohmelfs_mount(struct file_system_type *fs_type,
+		       int flags, const char *dev_name, void *data)
+{
+	return mount_nodev(fs_type, flags, data, pohmelfs_fill_super);
+}
+
+static void pohmelfs_kill_sb(struct super_block *sb)
+{
+	sync_inodes_sb(sb);
+	kill_anon_super(sb);
+}
+
+static struct file_system_type pohmelfs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "pohmelfs",
+	.mount		= pohmelfs_mount,
+	.kill_sb	= pohmelfs_kill_sb,
+};
+
+static void pohmelfs_cleanup_cache(void)
+{
+	kmem_cache_destroy(pohmelfs_trans_cache);
+	kmem_cache_destroy(pohmelfs_inode_cache);
+	kmem_cache_destroy(pohmelfs_inode_info_cache);
+	kmem_cache_destroy(pohmelfs_route_cache);
+	kmem_cache_destroy(pohmelfs_wait_cache);
+	kmem_cache_destroy(pohmelfs_io_cache);
+	kmem_cache_destroy(pohmelfs_inode_info_binary_package_cache);
+	kfree(pohmelfs_scratch_buf);
+	kmem_cache_destroy(pohmelfs_write_cache);
+	kmem_cache_destroy(pohmelfs_dentry_cache);
+}
+
+static int pohmelfs_init_cache(void)
+{
+	int err = -ENOMEM;
+
+	pohmelfs_inode_cache = KMEM_CACHE(pohmelfs_inode, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
+	if (!pohmelfs_inode_cache)
+		goto err_out_exit;
+
+	pohmelfs_trans_cache = KMEM_CACHE(pohmelfs_trans, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
+	if (!pohmelfs_trans_cache)
+		goto err_out_destroy_inode_cache;
+
+	pohmelfs_inode_info_cache = KMEM_CACHE(pohmelfs_inode_info, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
+	if (!pohmelfs_inode_info_cache)
+		goto err_out_destroy_trans_cache;
+
+	pohmelfs_route_cache = KMEM_CACHE(pohmelfs_route, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
+	if (!pohmelfs_route_cache)
+		goto err_out_destroy_inode_info_cache;
+
+	pohmelfs_wait_cache = KMEM_CACHE(pohmelfs_wait, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
+	if (!pohmelfs_wait_cache)
+		goto err_out_destroy_inode_info_cache;
+
+	pohmelfs_io_cache = KMEM_CACHE(pohmelfs_io, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
+	if (!pohmelfs_io_cache)
+		goto err_out_destroy_wait_cache;
+
+	pohmelfs_scratch_buf = kmalloc(pohmelfs_scratch_buf_size, GFP_KERNEL);
+	if (!pohmelfs_scratch_buf) {
+		err = -ENOMEM;
+		goto err_out_destroy_io_cache;
+	}
+
+	pohmelfs_inode_info_binary_package_cache = KMEM_CACHE(pohmelfs_inode_info_binary_package, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
+	if (!pohmelfs_inode_info_binary_package_cache)
+		goto err_out_free_scratch;
+
+	pohmelfs_write_cache = KMEM_CACHE(pohmelfs_write_ctl, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
+	if (!pohmelfs_write_cache)
+		goto err_out_destroy_inode_info_binary_package_cache;
+
+	pohmelfs_dentry_cache = KMEM_CACHE(pohmelfs_dentry, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
+	if (!pohmelfs_dentry_cache)
+		goto err_out_destroy_write_cache;
+
+	return 0;
+
+err_out_destroy_write_cache:
+	kmem_cache_destroy(pohmelfs_write_cache);
+err_out_destroy_inode_info_binary_package_cache:
+	kmem_cache_destroy(pohmelfs_inode_info_binary_package_cache);
+err_out_free_scratch:
+	kfree(pohmelfs_scratch_buf);
+err_out_destroy_io_cache:
+	kmem_cache_destroy(pohmelfs_io_cache);
+err_out_destroy_wait_cache:
+	kmem_cache_destroy(pohmelfs_wait_cache);
+err_out_destroy_inode_info_cache:
+	kmem_cache_destroy(pohmelfs_inode_info_cache);
+err_out_destroy_trans_cache:
+	kmem_cache_destroy(pohmelfs_trans_cache);
+err_out_destroy_inode_cache:
+	kmem_cache_destroy(pohmelfs_inode_cache);
+err_out_exit:
+	return err;
+}
+
+static int __init pohmelfs_init(void)
+{
+	int err;
+
+	err = pohmelfs_init_cache();
+	if (err)
+		goto err_out_exit;
+
+        err = register_filesystem(&pohmelfs_type);
+	if (err)
+		goto err_out_cleanup_cache;
+
+	return 0;
+
+err_out_cleanup_cache:
+	pohmelfs_cleanup_cache();
+err_out_exit:
+	return err;
+}
+
+static void __exit pohmelfs_exit(void)
+{
+	unregister_filesystem(&pohmelfs_type);
+	pohmelfs_cleanup_cache();
+}
+
+module_init(pohmelfs_init)
+module_exit(pohmelfs_exit)
+
+MODULE_AUTHOR("Evgeniy Polyakov <zbr@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("POHMELFS");
+MODULE_LICENSE("GPL");
diff --git a/fs/pohmelfs/symlink.c b/fs/pohmelfs/symlink.c
new file mode 100644
index 0000000..80a9d87
--- /dev/null
+++ b/fs/pohmelfs/symlink.c
@@ -0,0 +1,13 @@
+/*
+ * Copyright (C) 2011+ Evgeniy Polyakov <zbr@xxxxxxxxxxx>
+ */
+
+#include <linux/namei.h>
+
+#include "pohmelfs.h"
+
+const struct inode_operations pohmelfs_symlink_inode_operations = {
+	.readlink	= generic_readlink,
+	.follow_link	= page_follow_link_light,
+	.put_link	= page_put_link,
+};
diff --git a/fs/pohmelfs/trans.c b/fs/pohmelfs/trans.c
new file mode 100644
index 0000000..b8c8916
--- /dev/null
+++ b/fs/pohmelfs/trans.c
@@ -0,0 +1,429 @@
+/*
+ * Copyright (C) 2011+ Evgeniy Polyakov <zbr@xxxxxxxxxxx>
+ */
+
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+#include "pohmelfs.h"
+
+static void pohmelfs_trans_free(struct pohmelfs_trans *t)
+{
+	iput(t->inode);
+
+	kmem_cache_free(pohmelfs_trans_cache, t);
+}
+
+static void pohmelfs_trans_release(struct kref *kref)
+{
+	struct pohmelfs_trans *t = container_of(kref, struct pohmelfs_trans, refcnt);
+	struct pohmelfs_inode *pi = pohmelfs_inode(t->inode);
+
+	pr_debug("pohmelfs: %s: trans freed: %lu, io_offset: %llu, ino: %ld\n",
+			pohmelfs_dump_id(pi->id.id), t->trans, t->io_offset, t->inode->i_ino);
+
+	if (t->cb.destroy)
+		t->cb.destroy(t);
+
+	pohmelfs_state_put(t->st);
+
+	kfree(t->data);
+	kfree(t->recv_data);
+	pohmelfs_trans_free(t);
+}
+
+void pohmelfs_trans_put(struct pohmelfs_trans *t)
+{
+	kref_put(&t->refcnt, pohmelfs_trans_release);
+}
+
+struct pohmelfs_trans *pohmelfs_trans_alloc(struct inode *inode)
+{
+	struct pohmelfs_trans *t;
+	int err;
+
+	t = kmem_cache_zalloc(pohmelfs_trans_cache, GFP_NOIO);
+	if (!t) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	kref_init(&t->refcnt);
+
+	t->inode = igrab(inode);
+	if (!t->inode) {
+		err = -ENOENT;
+		goto err_out_free;
+	}
+
+	return t;
+
+err_out_free:
+	kmem_cache_free(pohmelfs_trans_cache, t);
+err_out_exit:
+	return ERR_PTR(err);
+}
+
+static int pohmelfs_buf_complete(struct pohmelfs_trans *t, struct pohmelfs_state *recv)
+{
+	struct pohmelfs_inode *pi = pohmelfs_inode(t->inode);
+	struct dnet_cmd *cmd = &recv->cmd;
+	unsigned long long trans = cmd->trans & ~DNET_TRANS_REPLY;
+
+	pr_debug("pohmelfs: %s: trans complete: %llu, flags: %x\n",
+			pohmelfs_dump_id(pi->id.id), trans, cmd->flags);
+
+	return 0;
+}
+
+static int pohmelfs_buf_recv(struct pohmelfs_trans *t, struct pohmelfs_state *recv)
+{
+	struct dnet_cmd *cmd = &recv->cmd;
+	int err;
+
+	if (!t->recv_data) {
+		t->recv_data = kmalloc(cmd->size, GFP_NOIO);
+		if (!t->recv_data) {
+			err = -ENOMEM;
+			goto err_out_exit;
+		}
+
+		t->io_offset = 0;
+	}
+
+	err = pohmelfs_data_recv(recv, t->recv_data + t->io_offset, cmd->size - t->io_offset, MSG_DONTWAIT);
+	if (err < 0)
+		goto err_out_exit;
+
+	t->io_offset += err;
+	err = 0;
+
+err_out_exit:
+	return err;
+}
+
+static int pohmelfs_init_callbacks(struct pohmelfs_trans *t, struct pohmelfs_io *pio)
+{
+	int err = 0;
+	struct pohmelfs_state *st = t->st;
+
+	t->priv = pio->priv;
+	t->cb = pio->cb;
+
+	if (!t->cb.complete)
+		t->cb.complete = pohmelfs_buf_complete;
+
+	if (!t->cb.recv_reply)
+		t->cb.recv_reply = pohmelfs_buf_recv;
+
+	if (t->cb.init) {
+		err = t->cb.init(t);
+		if (err)
+			goto err_out_exit;
+	}
+
+	pohmelfs_trans_insert(t);
+
+	pohmelfs_state_schedule(st);
+	pohmelfs_state_put(st);
+
+err_out_exit:
+	return err;
+}
+
+int pohmelfs_send_io_group(struct pohmelfs_io *pio, int group)
+{
+	struct pohmelfs_inode *pi = pio->pi;
+	struct inode *inode = &pi->vfs_inode;
+	struct pohmelfs_sb *psb = pohmelfs_sb(inode->i_sb);
+	struct pohmelfs_state *st;
+	struct pohmelfs_trans *t;
+	struct dnet_cmd *cmd;
+	struct dnet_attr *attr;
+	struct dnet_io_attr *io;
+	u64 iosize = pio->size;
+	u64 alloc_io_size = pio->size;
+	int err;
+
+	/* Dirty hack to prevent setting cmd/attr size to pio->size,
+	 * since in read command we specify in io->size number bytes we want,
+	 * and it should not be accounted in the packet we send to remote node
+	 */
+	if (pio->cmd == DNET_CMD_READ)
+		alloc_io_size = 0;
+
+	t = pohmelfs_trans_alloc(inode);
+	if (IS_ERR(t)) {
+		err = PTR_ERR(t);
+		goto err_out_exit;
+	}
+
+	st = pohmelfs_state_lookup(psb, pio->id, group, pio->size);
+	if (!st) {
+		err = -ENOENT;
+		goto err_out_free;
+	}
+
+	t->st = st;
+
+	/*
+	 * We already hold a reference grabbed in pohmelfs_state_lookup(), it is dropped when transaction is destroyed
+	 * We have to have valid state pointer to schedule sending, but after transaction is inserted into state's list,
+	 * it can be processed immediately and freed and grabbed reference pointer will dissapear.
+	 */
+	pohmelfs_state_get(st);
+
+	cmd = &t->cmd.cmd;
+	attr = &t->cmd.attr;
+	io = &t->cmd.p.io;
+
+	dnet_setup_id(&cmd->id, group, pio->id->id);
+	cmd->flags = pio->cflags;
+	cmd->trans = t->trans = atomic_long_inc_return(&psb->trans);
+	cmd->size = alloc_io_size + sizeof(struct dnet_io_attr) + sizeof(struct dnet_attr);
+
+	attr->cmd = pio->cmd;
+	attr->size = alloc_io_size + sizeof(struct dnet_io_attr);
+	attr->flags = pio->aflags;
+
+	memcpy(io->id, pio->id->id, DNET_ID_SIZE);
+	memcpy(io->parent, pio->id->id, DNET_ID_SIZE);
+	io->flags = pio->ioflags;
+	io->size = iosize;
+	io->offset = pio->offset;
+	io->type = pio->type;
+	io->start = pio->start;
+	io->num = pio->num;
+
+	t->header_size = sizeof(struct dnet_cmd) + sizeof(struct dnet_attr) + sizeof(struct dnet_io_attr);
+	t->data_size = alloc_io_size;
+
+	dnet_convert_cmd(cmd);
+	dnet_convert_attr(attr);
+	dnet_convert_io_attr(io);
+
+	t->wctl = pio->wctl;
+
+	if (pio->data) {
+		if (pio->alloc_flags & POHMELFS_IO_OWN) {
+			t->data = pio->data;
+		} else {
+			t->data = kmalloc(alloc_io_size, GFP_NOIO);
+			if (!t->data) {
+				err = -ENOMEM;
+				goto err_out_put_state;
+			}
+
+			memcpy(t->data, pio->data, alloc_io_size);
+		}
+	}
+
+	err = pohmelfs_init_callbacks(t, pio);
+	if (err)
+		goto err_out_put_state;
+
+
+	return 0;
+
+err_out_put_state:
+	pohmelfs_state_put(t->st);
+err_out_free:
+	pohmelfs_trans_free(t);
+err_out_exit:
+	return err;
+}
+
+int pohmelfs_send_io(struct pohmelfs_io *pio)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(pio->pi->vfs_inode.i_sb);
+	int i, err, err_num;
+
+	err = -ENOENT;
+	err_num = 0;
+
+	for (i = 0; i < psb->group_num; ++i) {
+		err = pohmelfs_send_io_group(pio, psb->groups[i]);
+		if (err)
+			err_num++;
+	}
+
+	return (err_num == psb->group_num) ? err : 0;
+}
+
+int pohmelfs_trans_insert(struct pohmelfs_trans *t)
+{
+	struct pohmelfs_state *st = t->st;
+
+	mutex_lock(&st->trans_lock);
+	list_add_tail(&t->trans_entry, &st->trans_list);
+	mutex_unlock(&st->trans_lock);
+
+	return 0;
+}
+
+void pohmelfs_trans_remove(struct pohmelfs_trans *t)
+{
+	struct pohmelfs_state *st = t->st;
+
+	mutex_lock(&st->trans_lock);
+	rb_erase(&t->trans_node, &st->trans_root);
+	mutex_unlock(&st->trans_lock);
+}
+
+static inline long pohmelfs_trans_cmp(struct pohmelfs_trans *t1, long trans)
+{
+	return t1->trans - trans;
+}
+
+/* Must be called under st->trans_lock */
+int pohmelfs_trans_insert_tree(struct pohmelfs_state *st, struct pohmelfs_trans *t)
+{
+	struct rb_node **n = &st->trans_root.rb_node, *parent = NULL;
+	struct pohmelfs_trans *tmp;
+	int err = 0;
+	long cmp;
+
+	while (*n) {
+		parent = *n;
+
+		tmp = rb_entry(parent, struct pohmelfs_trans, trans_node);
+
+		cmp = pohmelfs_trans_cmp(tmp, t->trans);
+		if (cmp < 0)
+			n = &parent->rb_left;
+		else if (cmp > 0)
+			n = &parent->rb_right;
+		else {
+			err = -EEXIST;
+			goto err_out_exit;
+		}
+	}
+
+	rb_link_node(&t->trans_node, parent, n);
+	rb_insert_color(&t->trans_node, &st->trans_root);
+
+err_out_exit:
+	return err;
+	
+}
+
+struct pohmelfs_trans *pohmelfs_trans_lookup(struct pohmelfs_state *st, struct dnet_cmd *cmd)
+{
+	struct pohmelfs_trans *t, *found = NULL;
+	u64 trans = cmd->trans & ~DNET_TRANS_REPLY;
+	struct rb_node *n = st->trans_root.rb_node;
+	long cmp;
+
+	mutex_lock(&st->trans_lock);
+	while (n) {
+		t = rb_entry(n, struct pohmelfs_trans, trans_node);
+
+		cmp = pohmelfs_trans_cmp(t, trans);
+		if (cmp < 0) {
+			n = n->rb_left;
+		} else if (cmp > 0)
+			n = n->rb_right;
+		else {
+			found = t;
+			kref_get(&t->refcnt);
+			break;
+		}
+	}
+	mutex_unlock(&st->trans_lock);
+
+	return found;
+}
+
+int pohmelfs_send_buf_single(struct pohmelfs_io *pio, struct pohmelfs_state *st)
+{
+	struct pohmelfs_inode *pi = pio->pi;
+	struct inode *inode = &pi->vfs_inode;
+	struct pohmelfs_sb *psb = pohmelfs_sb(inode->i_sb);
+	struct pohmelfs_trans *t;
+	struct dnet_cmd *cmd;
+	struct dnet_attr *attr;
+	int err;
+
+	t = pohmelfs_trans_alloc(inode);
+	if (IS_ERR(t)) {
+		err = PTR_ERR(t);
+		goto err_out_exit;
+	}
+
+	if (!st) {
+		st = pohmelfs_state_lookup(psb, pio->id, pio->group_id, pio->size);
+		if (!st) {
+			err = -ENOENT;
+			goto err_out_free;
+		}
+	} else {
+		pohmelfs_state_get(st);
+	}
+
+	t->st = st;
+	pohmelfs_state_get(st);
+
+	cmd = &t->cmd.cmd;
+	attr = &t->cmd.attr;
+
+	dnet_setup_id(&cmd->id, st->group_id, pio->id->id);
+	cmd->flags = pio->cflags;
+	cmd->trans = t->trans = atomic_long_inc_return(&psb->trans);
+	cmd->size = pio->size + sizeof(struct dnet_attr);
+
+	attr->cmd = pio->cmd;
+	attr->size = pio->size;
+	attr->flags = pio->aflags;
+
+	t->header_size = sizeof(struct dnet_cmd) + sizeof(struct dnet_attr);
+	t->data_size = pio->size;
+
+	dnet_convert_cmd(cmd);
+	dnet_convert_attr(attr);
+
+	if (pio->data) {
+		if (pio->alloc_flags & POHMELFS_IO_OWN) {
+			t->data = pio->data;
+		} else {
+			t->data = kmalloc(pio->size, GFP_NOIO);
+			if (!t->data) {
+				err = -ENOMEM;
+				goto err_out_put_state;
+			}
+
+			memcpy(t->data, pio->data, pio->size);
+		}
+	}
+
+	err = pohmelfs_init_callbacks(t, pio);
+	if (err)
+		goto err_out_put_state;
+
+	return 0;
+
+err_out_put_state:
+	pohmelfs_state_put(t->st);
+err_out_free:
+	pohmelfs_trans_free(t);
+err_out_exit:
+	return err;
+}
+
+int pohmelfs_send_buf(struct pohmelfs_io *pio)
+{
+	struct pohmelfs_sb *psb = pohmelfs_sb(pio->pi->vfs_inode.i_sb);
+	int i, err, err_num;
+
+	err = -ENOENT;
+	err_num = 0;
+
+	for (i = 0; i < psb->group_num; ++i) {
+		pio->group_id = psb->groups[i];
+
+		err = pohmelfs_send_buf_single(pio, NULL);
+		if (err)
+			err_num++;
+	}
+
+	return (err_num == psb->group_num) ? err : 0;
+}

-- 
	Evgeniy Polyakov
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/