#include <linux/ceph/ceph_debug.h>

  
  #include <linux/backing-dev.h>

  #include <linux/ctype.h>

  #include <linux/fs.h>
  #include <linux/inet.h>
  #include <linux/in6.h>
  #include <linux/module.h>
  #include <linux/mount.h>
  #include <linux/parser.h>

  #include <linux/sched.h>
  #include <linux/seq_file.h>

  #include <linux/slab.h>

  #include <linux/statfs.h>
  #include <linux/string.h>

  #include "super.h"

  #include "mds_client.h"
  
  #include <linux/ceph/decode.h>
  #include <linux/ceph/mon_client.h>
  #include <linux/ceph/auth.h>
  #include <linux/ceph/debugfs.h>

  
  /*
   * Ceph superblock operations
   *
   * Handle the basics of mounting, unmounting.
   */

  /*
   * super ops
   */
  static void ceph_put_super(struct super_block *s)
  {

  	struct ceph_fs_client *fsc = ceph_sb_to_client(s);

  
  	dout("put_super
  ");

  	ceph_mdsc_close_sessions(fsc->mdsc);

  
  	/*
  	 * ensure we release the bdi before put_anon_super releases
  	 * the device name.
  	 */

  	if (s->s_bdi == &fsc->backing_dev_info) {
  		bdi_unregister(&fsc->backing_dev_info);

  		s->s_bdi = NULL;
  	}

  	return;
  }
  
  static int ceph_statfs(struct dentry *dentry, struct kstatfs *buf)
  {

  	struct ceph_fs_client *fsc = ceph_inode_to_client(dentry->d_inode);
  	struct ceph_monmap *monmap = fsc->client->monc.monmap;

  	struct ceph_statfs st;
  	u64 fsid;
  	int err;
  
  	dout("statfs
  ");

  	err = ceph_monc_do_statfs(&fsc->client->monc, &st);

  	if (err < 0)
  		return err;
  
  	/* fill in kstatfs */
  	buf->f_type = CEPH_SUPER_MAGIC;  /* ?? */
  
  	/*
  	 * express utilization in terms of large blocks to avoid
  	 * overflow on 32-bit machines.
  	 */
  	buf->f_bsize = 1 << CEPH_BLOCK_SHIFT;
  	buf->f_blocks = le64_to_cpu(st.kb) >> (CEPH_BLOCK_SHIFT-10);

  	buf->f_bfree = le64_to_cpu(st.kb_avail) >> (CEPH_BLOCK_SHIFT-10);

  	buf->f_bavail = le64_to_cpu(st.kb_avail) >> (CEPH_BLOCK_SHIFT-10);
  
  	buf->f_files = le64_to_cpu(st.num_objects);
  	buf->f_ffree = -1;

  	buf->f_namelen = NAME_MAX;

  	buf->f_frsize = PAGE_CACHE_SIZE;
  
  	/* leave fsid little-endian, regardless of host endianness */
  	fsid = *(u64 *)(&monmap->fsid) ^ *((u64 *)&monmap->fsid + 1);
  	buf->f_fsid.val[0] = fsid & 0xffffffff;
  	buf->f_fsid.val[1] = fsid >> 32;
  
  	return 0;
  }

  static int ceph_sync_fs(struct super_block *sb, int wait)

  {

  	struct ceph_fs_client *fsc = ceph_sb_to_client(sb);

  
  	if (!wait) {
  		dout("sync_fs (non-blocking)
  ");

  		ceph_flush_dirty_caps(fsc->mdsc);

  		dout("sync_fs (non-blocking) done
  ");
  		return 0;
  	}
  
  	dout("sync_fs (blocking)
  ");

  	ceph_osdc_sync(&fsc->client->osdc);
  	ceph_mdsc_sync(fsc->mdsc);

  	dout("sync_fs (blocking) done
  ");

  	return 0;
  }

  /*
   * mount options
   */
  enum {

  	Opt_wsize,
  	Opt_rsize,

  	Opt_rasize,

  	Opt_caps_wanted_delay_min,
  	Opt_caps_wanted_delay_max,

  	Opt_cap_release_safety,

  	Opt_readdir_max_entries,

  	Opt_readdir_max_bytes,

  	Opt_congestion_kb,

  	Opt_last_int,

  	/* int args above */
  	Opt_snapdirname,

  	Opt_last_string,

  	/* string args above */

  	Opt_dirstat,
  	Opt_nodirstat,
  	Opt_rbytes,
  	Opt_norbytes,

  	Opt_noasyncreaddir,

  	Opt_dcache,
  	Opt_nodcache,

  	Opt_ino32,

  };

  static match_table_t fsopt_tokens = {

  	{Opt_wsize, "wsize=%d"},
  	{Opt_rsize, "rsize=%d"},

  	{Opt_rasize, "rasize=%d"},

  	{Opt_caps_wanted_delay_min, "caps_wanted_delay_min=%d"},
  	{Opt_caps_wanted_delay_max, "caps_wanted_delay_max=%d"},

  	{Opt_cap_release_safety, "cap_release_safety=%d"},

  	{Opt_readdir_max_entries, "readdir_max_entries=%d"},

  	{Opt_readdir_max_bytes, "readdir_max_bytes=%d"},

  	{Opt_congestion_kb, "write_congestion_kb=%d"},

  	/* int args above */
  	{Opt_snapdirname, "snapdirname=%s"},

  	/* string args above */

  	{Opt_dirstat, "dirstat"},
  	{Opt_nodirstat, "nodirstat"},
  	{Opt_rbytes, "rbytes"},
  	{Opt_norbytes, "norbytes"},

  	{Opt_noasyncreaddir, "noasyncreaddir"},

  	{Opt_dcache, "dcache"},
  	{Opt_nodcache, "nodcache"},

  	{Opt_ino32, "ino32"},

  	{-1, NULL}
  };

  static int parse_fsopt_token(char *c, void *private)

  {

  	struct ceph_mount_options *fsopt = private;
  	substring_t argstr[MAX_OPT_ARGS];
  	int token, intval, ret;
  
  	token = match_token((char *)c, fsopt_tokens, argstr);
  	if (token < 0)
  		return -EINVAL;
  
  	if (token < Opt_last_int) {
  		ret = match_int(&argstr[0], &intval);
  		if (ret < 0) {
  			pr_err("bad mount option arg (not int) "
  			       "at '%s'
  ", c);
  			return ret;

  		}

  		dout("got int token %d val %d
  ", token, intval);
  	} else if (token > Opt_last_int && token < Opt_last_string) {
  		dout("got string token %d val %s
  ", token,
  		     argstr[0].from);
  	} else {
  		dout("got token %d
  ", token);

  	}

  	switch (token) {
  	case Opt_snapdirname:
  		kfree(fsopt->snapdir_name);
  		fsopt->snapdir_name = kstrndup(argstr[0].from,
  					       argstr[0].to-argstr[0].from,
  					       GFP_KERNEL);
  		if (!fsopt->snapdir_name)
  			return -ENOMEM;
  		break;
  
  		/* misc */
  	case Opt_wsize:
  		fsopt->wsize = intval;
  		break;
  	case Opt_rsize:
  		fsopt->rsize = intval;
  		break;

  	case Opt_rasize:
  		fsopt->rasize = intval;
  		break;

  	case Opt_caps_wanted_delay_min:
  		fsopt->caps_wanted_delay_min = intval;
  		break;
  	case Opt_caps_wanted_delay_max:
  		fsopt->caps_wanted_delay_max = intval;
  		break;
  	case Opt_readdir_max_entries:
  		fsopt->max_readdir = intval;
  		break;
  	case Opt_readdir_max_bytes:
  		fsopt->max_readdir_bytes = intval;
  		break;
  	case Opt_congestion_kb:
  		fsopt->congestion_kb = intval;
  		break;
  	case Opt_dirstat:
  		fsopt->flags |= CEPH_MOUNT_OPT_DIRSTAT;
  		break;
  	case Opt_nodirstat:
  		fsopt->flags &= ~CEPH_MOUNT_OPT_DIRSTAT;
  		break;
  	case Opt_rbytes:
  		fsopt->flags |= CEPH_MOUNT_OPT_RBYTES;
  		break;
  	case Opt_norbytes:
  		fsopt->flags &= ~CEPH_MOUNT_OPT_RBYTES;
  		break;
  	case Opt_noasyncreaddir:
  		fsopt->flags |= CEPH_MOUNT_OPT_NOASYNCREADDIR;
  		break;

  	case Opt_dcache:
  		fsopt->flags |= CEPH_MOUNT_OPT_DCACHE;
  		break;
  	case Opt_nodcache:
  		fsopt->flags &= ~CEPH_MOUNT_OPT_DCACHE;
  		break;

  	case Opt_ino32:
  		fsopt->flags |= CEPH_MOUNT_OPT_INO32;
  		break;

  	default:
  		BUG_ON(token);
  	}
  	return 0;

  }

  static void destroy_mount_options(struct ceph_mount_options *args)

  {

  	dout("destroy_mount_options %p
  ", args);
  	kfree(args->snapdir_name);
  	kfree(args);
  }

  static int strcmp_null(const char *s1, const char *s2)
  {
  	if (!s1 && !s2)
  		return 0;
  	if (s1 && !s2)
  		return -1;
  	if (!s1 && s2)
  		return 1;
  	return strcmp(s1, s2);
  }

  static int compare_mount_options(struct ceph_mount_options *new_fsopt,
  				 struct ceph_options *new_opt,
  				 struct ceph_fs_client *fsc)
  {
  	struct ceph_mount_options *fsopt1 = new_fsopt;
  	struct ceph_mount_options *fsopt2 = fsc->mount_options;
  	int ofs = offsetof(struct ceph_mount_options, snapdir_name);
  	int ret;

  	ret = memcmp(fsopt1, fsopt2, ofs);
  	if (ret)
  		return ret;
  
  	ret = strcmp_null(fsopt1->snapdir_name, fsopt2->snapdir_name);
  	if (ret)
  		return ret;
  
  	return ceph_compare_options(new_opt, fsc->client);
  }
  
  static int parse_mount_options(struct ceph_mount_options **pfsopt,
  			       struct ceph_options **popt,
  			       int flags, char *options,
  			       const char *dev_name,
  			       const char **path)
  {
  	struct ceph_mount_options *fsopt;
  	const char *dev_name_end;
  	int err = -ENOMEM;
  
  	fsopt = kzalloc(sizeof(*fsopt), GFP_KERNEL);
  	if (!fsopt)
  		return -ENOMEM;
  
  	dout("parse_mount_options %p, dev_name '%s'
  ", fsopt, dev_name);

  	fsopt->sb_flags = flags;
  	fsopt->flags = CEPH_MOUNT_OPT_DEFAULT;

  	fsopt->rsize = CEPH_RSIZE_DEFAULT;
  	fsopt->rasize = CEPH_RASIZE_DEFAULT;
  	fsopt->snapdir_name = kstrdup(CEPH_SNAPDIRNAME_DEFAULT, GFP_KERNEL);

  	fsopt->caps_wanted_delay_min = CEPH_CAPS_WANTED_DELAY_MIN_DEFAULT;
  	fsopt->caps_wanted_delay_max = CEPH_CAPS_WANTED_DELAY_MAX_DEFAULT;

  	fsopt->cap_release_safety = CEPH_CAP_RELEASE_SAFETY_DEFAULT;
  	fsopt->max_readdir = CEPH_MAX_READDIR_DEFAULT;
  	fsopt->max_readdir_bytes = CEPH_MAX_READDIR_BYTES_DEFAULT;
  	fsopt->congestion_kb = default_congestion_kb();
  
  	/* ip1[:port1][,ip2[:port2]...]:/subdir/in/fs */
  	err = -EINVAL;
  	if (!dev_name)
  		goto out;
  	*path = strstr(dev_name, ":/");
  	if (*path == NULL) {
  		pr_err("device name is missing path (no :/ in %s)
  ",
  				dev_name);
  		goto out;
  	}

  	dev_name_end = *path;
  	dout("device name '%.*s'
  ", (int)(dev_name_end - dev_name), dev_name);

  	/* path on server */
  	*path += 2;
  	dout("server path '%s'
  ", *path);

  	err = ceph_parse_options(popt, options, dev_name, dev_name_end,
  				 parse_fsopt_token, (void *)fsopt);
  	if (err)
  		goto out;
  
  	/* success */
  	*pfsopt = fsopt;
  	return 0;

  out:

  	destroy_mount_options(fsopt);
  	return err;

  }

  /**
   * ceph_show_options - Show mount options in /proc/mounts
   * @m: seq_file to write to

   * @root: root of that (sub)tree

   */

  static int ceph_show_options(struct seq_file *m, struct dentry *root)

  {

  	struct ceph_fs_client *fsc = ceph_sb_to_client(root->d_sb);

  	struct ceph_mount_options *fsopt = fsc->mount_options;
  	struct ceph_options *opt = fsc->client->options;
  
  	if (opt->flags & CEPH_OPT_FSID)
  		seq_printf(m, ",fsid=%pU", &opt->fsid);
  	if (opt->flags & CEPH_OPT_NOSHARE)
  		seq_puts(m, ",noshare");
  	if (opt->flags & CEPH_OPT_NOCRC)
  		seq_puts(m, ",nocrc");
  
  	if (opt->name)
  		seq_printf(m, ",name=%s", opt->name);

  	if (opt->key)

  		seq_puts(m, ",secret=<hidden>");
  
  	if (opt->mount_timeout != CEPH_MOUNT_TIMEOUT_DEFAULT)
  		seq_printf(m, ",mount_timeout=%d", opt->mount_timeout);
  	if (opt->osd_idle_ttl != CEPH_OSD_IDLE_TTL_DEFAULT)
  		seq_printf(m, ",osd_idle_ttl=%d", opt->osd_idle_ttl);
  	if (opt->osd_timeout != CEPH_OSD_TIMEOUT_DEFAULT)
  		seq_printf(m, ",osdtimeout=%d", opt->osd_timeout);
  	if (opt->osd_keepalive_timeout != CEPH_OSD_KEEPALIVE_DEFAULT)
  		seq_printf(m, ",osdkeepalivetimeout=%d",
  			   opt->osd_keepalive_timeout);
  
  	if (fsopt->flags & CEPH_MOUNT_OPT_DIRSTAT)
  		seq_puts(m, ",dirstat");
  	if ((fsopt->flags & CEPH_MOUNT_OPT_RBYTES) == 0)
  		seq_puts(m, ",norbytes");
  	if (fsopt->flags & CEPH_MOUNT_OPT_NOASYNCREADDIR)
  		seq_puts(m, ",noasyncreaddir");

  	if (fsopt->flags & CEPH_MOUNT_OPT_DCACHE)
  		seq_puts(m, ",dcache");
  	else
  		seq_puts(m, ",nodcache");

  
  	if (fsopt->wsize)
  		seq_printf(m, ",wsize=%d", fsopt->wsize);

  	if (fsopt->rsize != CEPH_RSIZE_DEFAULT)

  		seq_printf(m, ",rsize=%d", fsopt->rsize);

  	if (fsopt->rasize != CEPH_RASIZE_DEFAULT)

  		seq_printf(m, ",rasize=%d", fsopt->rasize);

  	if (fsopt->congestion_kb != default_congestion_kb())
  		seq_printf(m, ",write_congestion_kb=%d", fsopt->congestion_kb);
  	if (fsopt->caps_wanted_delay_min != CEPH_CAPS_WANTED_DELAY_MIN_DEFAULT)
  		seq_printf(m, ",caps_wanted_delay_min=%d",
  			 fsopt->caps_wanted_delay_min);
  	if (fsopt->caps_wanted_delay_max != CEPH_CAPS_WANTED_DELAY_MAX_DEFAULT)
  		seq_printf(m, ",caps_wanted_delay_max=%d",
  			   fsopt->caps_wanted_delay_max);
  	if (fsopt->cap_release_safety != CEPH_CAP_RELEASE_SAFETY_DEFAULT)
  		seq_printf(m, ",cap_release_safety=%d",
  			   fsopt->cap_release_safety);
  	if (fsopt->max_readdir != CEPH_MAX_READDIR_DEFAULT)
  		seq_printf(m, ",readdir_max_entries=%d", fsopt->max_readdir);
  	if (fsopt->max_readdir_bytes != CEPH_MAX_READDIR_BYTES_DEFAULT)
  		seq_printf(m, ",readdir_max_bytes=%d", fsopt->max_readdir_bytes);
  	if (strcmp(fsopt->snapdir_name, CEPH_SNAPDIRNAME_DEFAULT))
  		seq_printf(m, ",snapdirname=%s", fsopt->snapdir_name);
  	return 0;

  }
  
  /*

   * handle any mon messages the standard library doesn't understand.
   * return error if we don't either.

   */

  static int extra_mon_dispatch(struct ceph_client *client, struct ceph_msg *msg)

  {

  	struct ceph_fs_client *fsc = client->private;
  	int type = le16_to_cpu(msg->hdr.type);
  
  	switch (type) {
  	case CEPH_MSG_MDS_MAP:
  		ceph_mdsc_handle_map(fsc->mdsc, msg);
  		return 0;
  
  	default:
  		return -1;
  	}
  }
  
  /*
   * create a new fs client
   */

  static struct ceph_fs_client *create_fs_client(struct ceph_mount_options *fsopt,

  					struct ceph_options *opt)
  {
  	struct ceph_fs_client *fsc;

  	const unsigned supported_features =
  		CEPH_FEATURE_FLOCK |
  		CEPH_FEATURE_DIRLAYOUTHASH;
  	const unsigned required_features = 0;

  	int err = -ENOMEM;

  	fsc = kzalloc(sizeof(*fsc), GFP_KERNEL);
  	if (!fsc)

  		return ERR_PTR(-ENOMEM);

  	fsc->client = ceph_create_client(opt, fsc, supported_features,
  					 required_features);

  	if (IS_ERR(fsc->client)) {
  		err = PTR_ERR(fsc->client);
  		goto fail;
  	}
  	fsc->client->extra_mon_dispatch = extra_mon_dispatch;

  	fsc->client->monc.want_mdsmap = 1;

  	fsc->mount_options = fsopt;

  	fsc->sb = NULL;
  	fsc->mount_state = CEPH_MOUNT_MOUNTING;

  	atomic_long_set(&fsc->writeback_count, 0);

  	err = bdi_init(&fsc->backing_dev_info);

  	if (err < 0)

  		goto fail_client;

  	err = -ENOMEM;

  	/*
  	 * The number of concurrent works can be high but they don't need
  	 * to be processed in parallel, limit concurrency.
  	 */
  	fsc->wb_wq = alloc_workqueue("ceph-writeback", 0, 1);

  	if (fsc->wb_wq == NULL)

  		goto fail_bdi;

  	fsc->pg_inv_wq = alloc_workqueue("ceph-pg-invalid", 0, 1);

  	if (fsc->pg_inv_wq == NULL)

  		goto fail_wb_wq;

  	fsc->trunc_wq = alloc_workqueue("ceph-trunc", 0, 1);

  	if (fsc->trunc_wq == NULL)

  		goto fail_pg_inv_wq;

  	/* set up mempools */
  	err = -ENOMEM;

  	fsc->wb_pagevec_pool = mempool_create_kmalloc_pool(10,
  			      fsc->mount_options->wsize >> PAGE_CACHE_SHIFT);
  	if (!fsc->wb_pagevec_pool)

  		goto fail_trunc_wq;

  	/* caps */

  	fsc->min_caps = fsopt->max_readdir;
  
  	return fsc;

  fail_trunc_wq:

  	destroy_workqueue(fsc->trunc_wq);

  fail_pg_inv_wq:

  	destroy_workqueue(fsc->pg_inv_wq);

  fail_wb_wq:

  	destroy_workqueue(fsc->wb_wq);

  fail_bdi:

  	bdi_destroy(&fsc->backing_dev_info);
  fail_client:
  	ceph_destroy_client(fsc->client);

  fail:

  	kfree(fsc);

  	return ERR_PTR(err);
  }

  static void destroy_fs_client(struct ceph_fs_client *fsc)

  {

  	dout("destroy_fs_client %p
  ", fsc);

  	destroy_workqueue(fsc->wb_wq);
  	destroy_workqueue(fsc->pg_inv_wq);
  	destroy_workqueue(fsc->trunc_wq);

  	bdi_destroy(&fsc->backing_dev_info);

  	mempool_destroy(fsc->wb_pagevec_pool);

  	destroy_mount_options(fsc->mount_options);

  	ceph_fs_debugfs_cleanup(fsc);

  	ceph_destroy_client(fsc->client);

  	kfree(fsc);
  	dout("destroy_fs_client %p done
  ", fsc);

  }
  
  /*

   * caches

   */

  struct kmem_cache *ceph_inode_cachep;
  struct kmem_cache *ceph_cap_cachep;
  struct kmem_cache *ceph_dentry_cachep;
  struct kmem_cache *ceph_file_cachep;
  
  static void ceph_inode_init_once(void *foo)

  {

  	struct ceph_inode_info *ci = foo;
  	inode_init_once(&ci->vfs_inode);
  }
  
  static int __init init_caches(void)
  {
  	ceph_inode_cachep = kmem_cache_create("ceph_inode_info",
  				      sizeof(struct ceph_inode_info),
  				      __alignof__(struct ceph_inode_info),
  				      (SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD),
  				      ceph_inode_init_once);
  	if (ceph_inode_cachep == NULL)
  		return -ENOMEM;
  
  	ceph_cap_cachep = KMEM_CACHE(ceph_cap,
  				     SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
  	if (ceph_cap_cachep == NULL)
  		goto bad_cap;
  
  	ceph_dentry_cachep = KMEM_CACHE(ceph_dentry_info,
  					SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
  	if (ceph_dentry_cachep == NULL)
  		goto bad_dentry;
  
  	ceph_file_cachep = KMEM_CACHE(ceph_file_info,
  				      SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
  	if (ceph_file_cachep == NULL)
  		goto bad_file;

  	return 0;

  
  bad_file:
  	kmem_cache_destroy(ceph_dentry_cachep);
  bad_dentry:
  	kmem_cache_destroy(ceph_cap_cachep);
  bad_cap:
  	kmem_cache_destroy(ceph_inode_cachep);
  	return -ENOMEM;

  }

  static void destroy_caches(void)
  {
  	kmem_cache_destroy(ceph_inode_cachep);
  	kmem_cache_destroy(ceph_cap_cachep);
  	kmem_cache_destroy(ceph_dentry_cachep);
  	kmem_cache_destroy(ceph_file_cachep);
  }

  /*

   * ceph_umount_begin - initiate forced umount.  Tear down down the
   * mount, skipping steps that may hang while waiting for server(s).

   */

  static void ceph_umount_begin(struct super_block *sb)

  {

  	struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
  
  	dout("ceph_umount_begin - starting forced umount
  ");
  	if (!fsc)
  		return;
  	fsc->mount_state = CEPH_MOUNT_SHUTDOWN;
  	return;

  }

  static const struct super_operations ceph_super_ops = {
  	.alloc_inode	= ceph_alloc_inode,
  	.destroy_inode	= ceph_destroy_inode,
  	.write_inode    = ceph_write_inode,
  	.sync_fs        = ceph_sync_fs,
  	.put_super	= ceph_put_super,
  	.show_options   = ceph_show_options,
  	.statfs		= ceph_statfs,
  	.umount_begin   = ceph_umount_begin,
  };

  /*
   * Bootstrap mount by opening the root directory.  Note the mount
   * @started time from caller, and time out if this takes too long.
   */

  static struct dentry *open_root_dentry(struct ceph_fs_client *fsc,

  				       const char *path,
  				       unsigned long started)
  {

  	struct ceph_mds_client *mdsc = fsc->mdsc;

  	struct ceph_mds_request *req = NULL;
  	int err;
  	struct dentry *root;
  
  	/* open dir */
  	dout("open_root_inode opening '%s'
  ", path);
  	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_GETATTR, USE_ANY_MDS);
  	if (IS_ERR(req))

  		return ERR_CAST(req);

  	req->r_path1 = kstrdup(path, GFP_NOFS);
  	req->r_ino1.ino = CEPH_INO_ROOT;
  	req->r_ino1.snap = CEPH_NOSNAP;
  	req->r_started = started;

  	req->r_timeout = fsc->client->options->mount_timeout * HZ;

  	req->r_args.getattr.mask = cpu_to_le32(CEPH_STAT_CAP_INODE);
  	req->r_num_caps = 2;
  	err = ceph_mdsc_do_request(mdsc, NULL, req);
  	if (err == 0) {

  		struct inode *inode = req->r_target_inode;
  		req->r_target_inode = NULL;

  		dout("open_root_inode success
  ");

  		if (ceph_ino(inode) == CEPH_INO_ROOT &&

  		    fsc->sb->s_root == NULL) {

  			root = d_alloc_root(inode);
  			if (!root) {
  				iput(inode);
  				root = ERR_PTR(-ENOMEM);
  				goto out;
  			}

  		} else {

  			root = d_obtain_alias(inode);

  		}

  		ceph_init_dentry(root);

  		dout("open_root_inode success, root dentry is %p
  ", root);
  	} else {
  		root = ERR_PTR(err);
  	}

  out:

  	ceph_mdsc_put_request(req);
  	return root;
  }

  /*
   * mount: join the ceph cluster, and open root directory.
   */

  static struct dentry *ceph_real_mount(struct ceph_fs_client *fsc,

  		      const char *path)
  {

  	int err;

  	unsigned long started = jiffies;  /* note the start time */
  	struct dentry *root;

  	int first = 0;   /* first vfsmount for this super_block */

  
  	dout("mount start
  ");

  	mutex_lock(&fsc->client->mount_mutex);

  	err = __ceph_open_session(fsc->client, started);

  	if (err < 0)
  		goto out;

  	dout("mount opening root
  ");

  	root = open_root_dentry(fsc, "", started);

  	if (IS_ERR(root)) {
  		err = PTR_ERR(root);
  		goto out;
  	}

  	if (fsc->sb->s_root) {

  		dput(root);

  	} else {
  		fsc->sb->s_root = root;
  		first = 1;
  
  		err = ceph_fs_debugfs_init(fsc);
  		if (err < 0)
  			goto fail;
  	}

  
  	if (path[0] == 0) {
  		dget(root);
  	} else {
  		dout("mount opening base mountpoint
  ");

  		root = open_root_dentry(fsc, path, started);

  		if (IS_ERR(root)) {
  			err = PTR_ERR(root);

  			goto fail;

  		}
  	}

  	fsc->mount_state = CEPH_MOUNT_MOUNTED;

  	dout("mount success
  ");

  	mutex_unlock(&fsc->client->mount_mutex);
  	return root;

  
  out:

  	mutex_unlock(&fsc->client->mount_mutex);

  	return ERR_PTR(err);

  
  fail:
  	if (first) {
  		dput(fsc->sb->s_root);
  		fsc->sb->s_root = NULL;
  	}
  	goto out;

  }
  
  static int ceph_set_super(struct super_block *s, void *data)
  {

  	struct ceph_fs_client *fsc = data;

  	int ret;
  
  	dout("set_super %p data %p
  ", s, data);

  	s->s_flags = fsc->mount_options->sb_flags;

  	s->s_maxbytes = 1ULL << 40;  /* temp value until we get mdsmap */

  	s->s_fs_info = fsc;
  	fsc->sb = s;

  
  	s->s_op = &ceph_super_ops;
  	s->s_export_op = &ceph_export_ops;
  
  	s->s_time_gran = 1000;  /* 1000 ns == 1 us */
  
  	ret = set_anon_super(s, NULL);  /* what is that second arg for? */
  	if (ret != 0)
  		goto fail;
  
  	return ret;
  
  fail:
  	s->s_fs_info = NULL;

  	fsc->sb = NULL;

  	return ret;
  }
  
  /*
   * share superblock if same fs AND options
   */
  static int ceph_compare_super(struct super_block *sb, void *data)
  {

  	struct ceph_fs_client *new = data;
  	struct ceph_mount_options *fsopt = new->mount_options;
  	struct ceph_options *opt = new->client->options;
  	struct ceph_fs_client *other = ceph_sb_to_client(sb);

  
  	dout("ceph_compare_super %p
  ", sb);

  
  	if (compare_mount_options(fsopt, opt, other)) {
  		dout("monitor(s)/mount options don't match
  ");
  		return 0;

  	}

  	if ((opt->flags & CEPH_OPT_FSID) &&
  	    ceph_fsid_compare(&opt->fsid, &other->client->fsid)) {
  		dout("fsid doesn't match
  ");
  		return 0;
  	}
  	if (fsopt->sb_flags != other->mount_options->sb_flags) {

  		dout("flags differ
  ");
  		return 0;
  	}
  	return 1;
  }
  
  /*
   * construct our own bdi so we can control readahead, etc.
   */

  static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);

  static int ceph_register_bdi(struct super_block *sb,
  			     struct ceph_fs_client *fsc)

  {
  	int err;

  	/* set ra_pages based on rasize mount option? */
  	if (fsc->mount_options->rasize >= PAGE_CACHE_SIZE)

  		fsc->backing_dev_info.ra_pages =

  			(fsc->mount_options->rasize + PAGE_CACHE_SIZE - 1)

  			>> PAGE_SHIFT;

  	else
  		fsc->backing_dev_info.ra_pages =
  			default_backing_dev_info.ra_pages;

  	err = bdi_register(&fsc->backing_dev_info, NULL, "ceph-%d",

  			   atomic_long_inc_return(&bdi_seq));

  	if (!err)

  		sb->s_bdi = &fsc->backing_dev_info;

  	return err;
  }

  static struct dentry *ceph_mount(struct file_system_type *fs_type,
  		       int flags, const char *dev_name, void *data)

  {
  	struct super_block *sb;

  	struct ceph_fs_client *fsc;

  	struct dentry *res;

  	int err;
  	int (*compare_super)(struct super_block *, void *) = ceph_compare_super;

  	const char *path = NULL;

  	struct ceph_mount_options *fsopt = NULL;
  	struct ceph_options *opt = NULL;

  	dout("ceph_mount
  ");

  	err = parse_mount_options(&fsopt, &opt, flags, data, dev_name, &path);

  	if (err < 0) {
  		res = ERR_PTR(err);

  		goto out_final;

  	}

  
  	/* create client (which we may/may not use) */

  	fsc = create_fs_client(fsopt, opt);
  	if (IS_ERR(fsc)) {

  		res = ERR_CAST(fsc);

  		destroy_mount_options(fsopt);
  		ceph_destroy_options(opt);

  		goto out_final;
  	}

  	err = ceph_mdsc_init(fsc);

  	if (err < 0) {
  		res = ERR_PTR(err);

  		goto out;

  	}

  
  	if (ceph_test_opt(fsc->client, NOSHARE))

  		compare_super = NULL;

  	sb = sget(fs_type, compare_super, ceph_set_super, fsc);

  	if (IS_ERR(sb)) {

  		res = ERR_CAST(sb);

  		goto out;
  	}

  	if (ceph_sb_to_client(sb) != fsc) {
  		ceph_mdsc_destroy(fsc);
  		destroy_fs_client(fsc);
  		fsc = ceph_sb_to_client(sb);
  		dout("get_sb got existing client %p
  ", fsc);

  	} else {

  		dout("get_sb using new client %p
  ", fsc);
  		err = ceph_register_bdi(sb, fsc);

  		if (err < 0) {
  			res = ERR_PTR(err);

  			goto out_splat;

  		}

  	}

  	res = ceph_real_mount(fsc, path);
  	if (IS_ERR(res))

  		goto out_splat;

  	dout("root %p inode %p ino %llx.%llx
  ", res,
  	     res->d_inode, ceph_vinop(res->d_inode));
  	return res;

  
  out_splat:

  	ceph_mdsc_close_sessions(fsc->mdsc);

  	deactivate_locked_super(sb);

  	goto out_final;
  
  out:

  	ceph_mdsc_destroy(fsc);
  	destroy_fs_client(fsc);

  out_final:

  	dout("ceph_mount fail %ld
  ", PTR_ERR(res));
  	return res;

  }
  
  static void ceph_kill_sb(struct super_block *s)
  {

  	struct ceph_fs_client *fsc = ceph_sb_to_client(s);

  	dout("kill_sb %p
  ", s);

  	ceph_mdsc_pre_umount(fsc->mdsc);

  	kill_anon_super(s);    /* will call put_super after sb is r/o */

  	ceph_mdsc_destroy(fsc);
  	destroy_fs_client(fsc);

  }
  
  static struct file_system_type ceph_fs_type = {
  	.owner		= THIS_MODULE,
  	.name		= "ceph",

  	.mount		= ceph_mount,

  	.kill_sb	= ceph_kill_sb,
  	.fs_flags	= FS_RENAME_DOES_D_MOVE,
  };
  
  #define _STRINGIFY(x) #x
  #define STRINGIFY(x) _STRINGIFY(x)
  
  static int __init init_ceph(void)
  {

  	int ret = init_caches();

  	if (ret)

  		goto out;

  	ret = register_filesystem(&ceph_fs_type);
  	if (ret)
  		goto out_icache;

  	pr_info("loaded (mds proto %d)
  ", CEPH_MDSC_PROTOCOL);

  	return 0;
  
  out_icache:
  	destroy_caches();

  out:
  	return ret;
  }
  
  static void __exit exit_ceph(void)
  {
  	dout("exit_ceph
  ");
  	unregister_filesystem(&ceph_fs_type);

  	destroy_caches();

  }
  
  module_init(init_ceph);
  module_exit(exit_ceph);
  
  MODULE_AUTHOR("Sage Weil <sage@newdream.net>");
  MODULE_AUTHOR("Yehuda Sadeh <yehuda@hq.newdream.net>");
  MODULE_AUTHOR("Patience Warnick <patience@newdream.net>");
  MODULE_DESCRIPTION("Ceph filesystem for Linux");
  MODULE_LICENSE("GPL");