#include <linux/ceph/ceph_debug.h>

  
  #include <linux/module.h>
  #include <linux/fs.h>

  #include <linux/slab.h>
  #include <linux/string.h>
  #include <linux/uaccess.h>
  #include <linux/kernel.h>
  #include <linux/namei.h>
  #include <linux/writeback.h>
  #include <linux/vmalloc.h>
  
  #include "super.h"

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

  
  /*
   * Ceph inode operations
   *
   * Implement basic inode helpers (get, alloc) and inode ops (getattr,
   * setattr, etc.), xattr helpers, and helpers for assimilating
   * metadata returned by the MDS into our cache.
   *
   * Also define helpers for doing asynchronous writeback, invalidation,
   * and truncation for the benefit of those who can't afford to block
   * (typically because they are in the message handler path).
   */
  
  static const struct inode_operations ceph_symlink_iops;

  static void ceph_invalidate_work(struct work_struct *work);
  static void ceph_writeback_work(struct work_struct *work);
  static void ceph_vmtruncate_work(struct work_struct *work);

  
  /*
   * find or create an inode, given the ceph ino number
   */

  static int ceph_set_ino_cb(struct inode *inode, void *data)
  {
  	ceph_inode(inode)->i_vino = *(struct ceph_vino *)data;
  	inode->i_ino = ceph_vino_to_ino(*(struct ceph_vino *)data);
  	return 0;
  }

  struct inode *ceph_get_inode(struct super_block *sb, struct ceph_vino vino)
  {
  	struct inode *inode;
  	ino_t t = ceph_vino_to_ino(vino);
  
  	inode = iget5_locked(sb, t, ceph_ino_compare, ceph_set_ino_cb, &vino);
  	if (inode == NULL)
  		return ERR_PTR(-ENOMEM);
  	if (inode->i_state & I_NEW) {
  		dout("get_inode created new inode %p %llx.%llx ino %llx
  ",
  		     inode, ceph_vinop(inode), (u64)inode->i_ino);
  		unlock_new_inode(inode);
  	}
  
  	dout("get_inode on %lu=%llx.%llx got %p
  ", inode->i_ino, vino.ino,
  	     vino.snap, inode);
  	return inode;
  }
  
  /*
   * get/constuct snapdir inode for a given directory
   */
  struct inode *ceph_get_snapdir(struct inode *parent)
  {
  	struct ceph_vino vino = {
  		.ino = ceph_ino(parent),
  		.snap = CEPH_SNAPDIR,
  	};
  	struct inode *inode = ceph_get_inode(parent->i_sb, vino);

  	struct ceph_inode_info *ci = ceph_inode(inode);

  
  	BUG_ON(!S_ISDIR(parent->i_mode));
  	if (IS_ERR(inode))

  		return inode;

  	inode->i_mode = parent->i_mode;
  	inode->i_uid = parent->i_uid;
  	inode->i_gid = parent->i_gid;
  	inode->i_op = &ceph_dir_iops;
  	inode->i_fop = &ceph_dir_fops;

  	ci->i_snap_caps = CEPH_CAP_PIN; /* so we can open */
  	ci->i_rbytes = 0;

  	return inode;
  }
  
  const struct inode_operations ceph_file_iops = {
  	.permission = ceph_permission,
  	.setattr = ceph_setattr,
  	.getattr = ceph_getattr,
  	.setxattr = ceph_setxattr,
  	.getxattr = ceph_getxattr,
  	.listxattr = ceph_listxattr,
  	.removexattr = ceph_removexattr,
  };
  
  
  /*
   * We use a 'frag tree' to keep track of the MDS's directory fragments
   * for a given inode (usually there is just a single fragment).  We
   * need to know when a child frag is delegated to a new MDS, or when
   * it is flagged as replicated, so we can direct our requests
   * accordingly.
   */
  
  /*
   * find/create a frag in the tree
   */
  static struct ceph_inode_frag *__get_or_create_frag(struct ceph_inode_info *ci,
  						    u32 f)
  {
  	struct rb_node **p;
  	struct rb_node *parent = NULL;
  	struct ceph_inode_frag *frag;
  	int c;
  
  	p = &ci->i_fragtree.rb_node;
  	while (*p) {
  		parent = *p;
  		frag = rb_entry(parent, struct ceph_inode_frag, node);
  		c = ceph_frag_compare(f, frag->frag);
  		if (c < 0)
  			p = &(*p)->rb_left;
  		else if (c > 0)
  			p = &(*p)->rb_right;
  		else
  			return frag;
  	}
  
  	frag = kmalloc(sizeof(*frag), GFP_NOFS);
  	if (!frag) {
  		pr_err("__get_or_create_frag ENOMEM on %p %llx.%llx "
  		       "frag %x
  ", &ci->vfs_inode,
  		       ceph_vinop(&ci->vfs_inode), f);
  		return ERR_PTR(-ENOMEM);
  	}
  	frag->frag = f;
  	frag->split_by = 0;
  	frag->mds = -1;
  	frag->ndist = 0;
  
  	rb_link_node(&frag->node, parent, p);
  	rb_insert_color(&frag->node, &ci->i_fragtree);
  
  	dout("get_or_create_frag added %llx.%llx frag %x
  ",
  	     ceph_vinop(&ci->vfs_inode), f);
  	return frag;
  }
  
  /*
   * find a specific frag @f
   */
  struct ceph_inode_frag *__ceph_find_frag(struct ceph_inode_info *ci, u32 f)
  {
  	struct rb_node *n = ci->i_fragtree.rb_node;
  
  	while (n) {
  		struct ceph_inode_frag *frag =
  			rb_entry(n, struct ceph_inode_frag, node);
  		int c = ceph_frag_compare(f, frag->frag);
  		if (c < 0)
  			n = n->rb_left;
  		else if (c > 0)
  			n = n->rb_right;
  		else
  			return frag;
  	}
  	return NULL;
  }
  
  /*
   * Choose frag containing the given value @v.  If @pfrag is
   * specified, copy the frag delegation info to the caller if
   * it is present.
   */
  u32 ceph_choose_frag(struct ceph_inode_info *ci, u32 v,
  		     struct ceph_inode_frag *pfrag,
  		     int *found)
  {
  	u32 t = ceph_frag_make(0, 0);
  	struct ceph_inode_frag *frag;
  	unsigned nway, i;
  	u32 n;
  
  	if (found)
  		*found = 0;
  
  	mutex_lock(&ci->i_fragtree_mutex);
  	while (1) {
  		WARN_ON(!ceph_frag_contains_value(t, v));
  		frag = __ceph_find_frag(ci, t);
  		if (!frag)
  			break; /* t is a leaf */
  		if (frag->split_by == 0) {
  			if (pfrag)
  				memcpy(pfrag, frag, sizeof(*pfrag));
  			if (found)
  				*found = 1;
  			break;
  		}
  
  		/* choose child */
  		nway = 1 << frag->split_by;
  		dout("choose_frag(%x) %x splits by %d (%d ways)
  ", v, t,
  		     frag->split_by, nway);
  		for (i = 0; i < nway; i++) {
  			n = ceph_frag_make_child(t, frag->split_by, i);
  			if (ceph_frag_contains_value(n, v)) {
  				t = n;
  				break;
  			}
  		}
  		BUG_ON(i == nway);
  	}
  	dout("choose_frag(%x) = %x
  ", v, t);
  
  	mutex_unlock(&ci->i_fragtree_mutex);
  	return t;
  }
  
  /*
   * Process dirfrag (delegation) info from the mds.  Include leaf
   * fragment in tree ONLY if ndist > 0.  Otherwise, only
   * branches/splits are included in i_fragtree)
   */
  static int ceph_fill_dirfrag(struct inode *inode,
  			     struct ceph_mds_reply_dirfrag *dirinfo)
  {
  	struct ceph_inode_info *ci = ceph_inode(inode);
  	struct ceph_inode_frag *frag;
  	u32 id = le32_to_cpu(dirinfo->frag);
  	int mds = le32_to_cpu(dirinfo->auth);
  	int ndist = le32_to_cpu(dirinfo->ndist);
  	int i;
  	int err = 0;
  
  	mutex_lock(&ci->i_fragtree_mutex);
  	if (ndist == 0) {
  		/* no delegation info needed. */
  		frag = __ceph_find_frag(ci, id);
  		if (!frag)
  			goto out;
  		if (frag->split_by == 0) {
  			/* tree leaf, remove */
  			dout("fill_dirfrag removed %llx.%llx frag %x"
  			     " (no ref)
  ", ceph_vinop(inode), id);
  			rb_erase(&frag->node, &ci->i_fragtree);
  			kfree(frag);
  		} else {
  			/* tree branch, keep and clear */
  			dout("fill_dirfrag cleared %llx.%llx frag %x"
  			     " referral
  ", ceph_vinop(inode), id);
  			frag->mds = -1;
  			frag->ndist = 0;
  		}
  		goto out;
  	}
  
  
  	/* find/add this frag to store mds delegation info */
  	frag = __get_or_create_frag(ci, id);
  	if (IS_ERR(frag)) {
  		/* this is not the end of the world; we can continue
  		   with bad/inaccurate delegation info */
  		pr_err("fill_dirfrag ENOMEM on mds ref %llx.%llx fg %x
  ",
  		       ceph_vinop(inode), le32_to_cpu(dirinfo->frag));
  		err = -ENOMEM;
  		goto out;
  	}
  
  	frag->mds = mds;
  	frag->ndist = min_t(u32, ndist, CEPH_MAX_DIRFRAG_REP);
  	for (i = 0; i < frag->ndist; i++)
  		frag->dist[i] = le32_to_cpu(dirinfo->dist[i]);
  	dout("fill_dirfrag %llx.%llx frag %x ndist=%d
  ",
  	     ceph_vinop(inode), frag->frag, frag->ndist);
  
  out:
  	mutex_unlock(&ci->i_fragtree_mutex);
  	return err;
  }
  
  
  /*
   * initialize a newly allocated inode.
   */
  struct inode *ceph_alloc_inode(struct super_block *sb)
  {
  	struct ceph_inode_info *ci;
  	int i;
  
  	ci = kmem_cache_alloc(ceph_inode_cachep, GFP_NOFS);
  	if (!ci)
  		return NULL;
  
  	dout("alloc_inode %p
  ", &ci->vfs_inode);

  	spin_lock_init(&ci->i_ceph_lock);

  	ci->i_version = 0;
  	ci->i_time_warp_seq = 0;
  	ci->i_ceph_flags = 0;
  	ci->i_release_count = 0;
  	ci->i_symlink = NULL;

  	memset(&ci->i_dir_layout, 0, sizeof(ci->i_dir_layout));

  	ci->i_fragtree = RB_ROOT;
  	mutex_init(&ci->i_fragtree_mutex);
  
  	ci->i_xattrs.blob = NULL;
  	ci->i_xattrs.prealloc_blob = NULL;
  	ci->i_xattrs.dirty = false;
  	ci->i_xattrs.index = RB_ROOT;
  	ci->i_xattrs.count = 0;
  	ci->i_xattrs.names_size = 0;
  	ci->i_xattrs.vals_size = 0;
  	ci->i_xattrs.version = 0;
  	ci->i_xattrs.index_version = 0;
  
  	ci->i_caps = RB_ROOT;
  	ci->i_auth_cap = NULL;
  	ci->i_dirty_caps = 0;
  	ci->i_flushing_caps = 0;
  	INIT_LIST_HEAD(&ci->i_dirty_item);
  	INIT_LIST_HEAD(&ci->i_flushing_item);
  	ci->i_cap_flush_seq = 0;
  	ci->i_cap_flush_last_tid = 0;
  	memset(&ci->i_cap_flush_tid, 0, sizeof(ci->i_cap_flush_tid));
  	init_waitqueue_head(&ci->i_cap_wq);
  	ci->i_hold_caps_min = 0;
  	ci->i_hold_caps_max = 0;
  	INIT_LIST_HEAD(&ci->i_cap_delay_list);
  	ci->i_cap_exporting_mds = 0;
  	ci->i_cap_exporting_mseq = 0;
  	ci->i_cap_exporting_issued = 0;
  	INIT_LIST_HEAD(&ci->i_cap_snaps);
  	ci->i_head_snapc = NULL;
  	ci->i_snap_caps = 0;
  
  	for (i = 0; i < CEPH_FILE_MODE_NUM; i++)
  		ci->i_nr_by_mode[i] = 0;
  
  	ci->i_truncate_seq = 0;
  	ci->i_truncate_size = 0;
  	ci->i_truncate_pending = 0;
  
  	ci->i_max_size = 0;
  	ci->i_reported_size = 0;
  	ci->i_wanted_max_size = 0;
  	ci->i_requested_max_size = 0;
  
  	ci->i_pin_ref = 0;
  	ci->i_rd_ref = 0;
  	ci->i_rdcache_ref = 0;
  	ci->i_wr_ref = 0;

  	ci->i_wb_ref = 0;

  	ci->i_wrbuffer_ref = 0;
  	ci->i_wrbuffer_ref_head = 0;
  	ci->i_shared_gen = 0;
  	ci->i_rdcache_gen = 0;
  	ci->i_rdcache_revoking = 0;
  
  	INIT_LIST_HEAD(&ci->i_unsafe_writes);
  	INIT_LIST_HEAD(&ci->i_unsafe_dirops);
  	spin_lock_init(&ci->i_unsafe_lock);
  
  	ci->i_snap_realm = NULL;
  	INIT_LIST_HEAD(&ci->i_snap_realm_item);
  	INIT_LIST_HEAD(&ci->i_snap_flush_item);

  	INIT_WORK(&ci->i_wb_work, ceph_writeback_work);
  	INIT_WORK(&ci->i_pg_inv_work, ceph_invalidate_work);

  
  	INIT_WORK(&ci->i_vmtruncate_work, ceph_vmtruncate_work);
  
  	return &ci->vfs_inode;
  }

  static void ceph_i_callback(struct rcu_head *head)
  {
  	struct inode *inode = container_of(head, struct inode, i_rcu);
  	struct ceph_inode_info *ci = ceph_inode(inode);

  	kmem_cache_free(ceph_inode_cachep, ci);
  }

  void ceph_destroy_inode(struct inode *inode)
  {
  	struct ceph_inode_info *ci = ceph_inode(inode);
  	struct ceph_inode_frag *frag;
  	struct rb_node *n;
  
  	dout("destroy_inode %p ino %llx.%llx
  ", inode, ceph_vinop(inode));
  
  	ceph_queue_caps_release(inode);

  	/*
  	 * we may still have a snap_realm reference if there are stray
  	 * caps in i_cap_exporting_issued or i_snap_caps.
  	 */
  	if (ci->i_snap_realm) {
  		struct ceph_mds_client *mdsc =

  			ceph_sb_to_client(ci->vfs_inode.i_sb)->mdsc;

  		struct ceph_snap_realm *realm = ci->i_snap_realm;
  
  		dout(" dropping residual ref to snap realm %p
  ", realm);
  		spin_lock(&realm->inodes_with_caps_lock);
  		list_del_init(&ci->i_snap_realm_item);
  		spin_unlock(&realm->inodes_with_caps_lock);
  		ceph_put_snap_realm(mdsc, realm);
  	}

  	kfree(ci->i_symlink);
  	while ((n = rb_first(&ci->i_fragtree)) != NULL) {
  		frag = rb_entry(n, struct ceph_inode_frag, node);
  		rb_erase(n, &ci->i_fragtree);
  		kfree(frag);
  	}
  
  	__ceph_destroy_xattrs(ci);

  	if (ci->i_xattrs.blob)
  		ceph_buffer_put(ci->i_xattrs.blob);
  	if (ci->i_xattrs.prealloc_blob)
  		ceph_buffer_put(ci->i_xattrs.prealloc_blob);

  	call_rcu(&inode->i_rcu, ceph_i_callback);

  }
  
  
  /*
   * Helpers to fill in size, ctime, mtime, and atime.  We have to be
   * careful because either the client or MDS may have more up to date
   * info, depending on which capabilities are held, and whether
   * time_warp_seq or truncate_seq have increased.  (Ordinarily, mtime
   * and size are monotonically increasing, except when utimes() or
   * truncate() increments the corresponding _seq values.)
   */
  int ceph_fill_file_size(struct inode *inode, int issued,
  			u32 truncate_seq, u64 truncate_size, u64 size)
  {
  	struct ceph_inode_info *ci = ceph_inode(inode);
  	int queue_trunc = 0;
  
  	if (ceph_seq_cmp(truncate_seq, ci->i_truncate_seq) > 0 ||
  	    (truncate_seq == ci->i_truncate_seq && size > inode->i_size)) {
  		dout("size %lld -> %llu
  ", inode->i_size, size);
  		inode->i_size = size;
  		inode->i_blocks = (size + (1<<9) - 1) >> 9;
  		ci->i_reported_size = size;
  		if (truncate_seq != ci->i_truncate_seq) {
  			dout("truncate_seq %u -> %u
  ",
  			     ci->i_truncate_seq, truncate_seq);
  			ci->i_truncate_seq = truncate_seq;

  			/*
  			 * If we hold relevant caps, or in the case where we're
  			 * not the only client referencing this file and we
  			 * don't hold those caps, then we need to check whether
  			 * the file is either opened or mmaped
  			 */
  			if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_RD|

  				       CEPH_CAP_FILE_WR|CEPH_CAP_FILE_BUFFER|
  				       CEPH_CAP_FILE_EXCL|
  				       CEPH_CAP_FILE_LAZYIO)) ||

  			    mapping_mapped(inode->i_mapping) ||
  			    __ceph_caps_file_wanted(ci)) {

  				ci->i_truncate_pending++;
  				queue_trunc = 1;
  			}
  		}
  	}
  	if (ceph_seq_cmp(truncate_seq, ci->i_truncate_seq) >= 0 &&
  	    ci->i_truncate_size != truncate_size) {
  		dout("truncate_size %lld -> %llu
  ", ci->i_truncate_size,
  		     truncate_size);
  		ci->i_truncate_size = truncate_size;
  	}
  	return queue_trunc;
  }
  
  void ceph_fill_file_time(struct inode *inode, int issued,
  			 u64 time_warp_seq, struct timespec *ctime,
  			 struct timespec *mtime, struct timespec *atime)
  {
  	struct ceph_inode_info *ci = ceph_inode(inode);
  	int warn = 0;
  
  	if (issued & (CEPH_CAP_FILE_EXCL|
  		      CEPH_CAP_FILE_WR|

  		      CEPH_CAP_FILE_BUFFER|
  		      CEPH_CAP_AUTH_EXCL|
  		      CEPH_CAP_XATTR_EXCL)) {

  		if (timespec_compare(ctime, &inode->i_ctime) > 0) {
  			dout("ctime %ld.%09ld -> %ld.%09ld inc w/ cap
  ",
  			     inode->i_ctime.tv_sec, inode->i_ctime.tv_nsec,
  			     ctime->tv_sec, ctime->tv_nsec);
  			inode->i_ctime = *ctime;
  		}
  		if (ceph_seq_cmp(time_warp_seq, ci->i_time_warp_seq) > 0) {
  			/* the MDS did a utimes() */
  			dout("mtime %ld.%09ld -> %ld.%09ld "
  			     "tw %d -> %d
  ",
  			     inode->i_mtime.tv_sec, inode->i_mtime.tv_nsec,
  			     mtime->tv_sec, mtime->tv_nsec,
  			     ci->i_time_warp_seq, (int)time_warp_seq);
  
  			inode->i_mtime = *mtime;
  			inode->i_atime = *atime;
  			ci->i_time_warp_seq = time_warp_seq;
  		} else if (time_warp_seq == ci->i_time_warp_seq) {
  			/* nobody did utimes(); take the max */
  			if (timespec_compare(mtime, &inode->i_mtime) > 0) {
  				dout("mtime %ld.%09ld -> %ld.%09ld inc
  ",
  				     inode->i_mtime.tv_sec,
  				     inode->i_mtime.tv_nsec,
  				     mtime->tv_sec, mtime->tv_nsec);
  				inode->i_mtime = *mtime;
  			}
  			if (timespec_compare(atime, &inode->i_atime) > 0) {
  				dout("atime %ld.%09ld -> %ld.%09ld inc
  ",
  				     inode->i_atime.tv_sec,
  				     inode->i_atime.tv_nsec,
  				     atime->tv_sec, atime->tv_nsec);
  				inode->i_atime = *atime;
  			}
  		} else if (issued & CEPH_CAP_FILE_EXCL) {
  			/* we did a utimes(); ignore mds values */
  		} else {
  			warn = 1;
  		}
  	} else {

  		/* we have no write|excl caps; whatever the MDS says is true */

  		if (ceph_seq_cmp(time_warp_seq, ci->i_time_warp_seq) >= 0) {
  			inode->i_ctime = *ctime;
  			inode->i_mtime = *mtime;
  			inode->i_atime = *atime;
  			ci->i_time_warp_seq = time_warp_seq;
  		} else {
  			warn = 1;
  		}
  	}
  	if (warn) /* time_warp_seq shouldn't go backwards */
  		dout("%p mds time_warp_seq %llu < %u
  ",
  		     inode, time_warp_seq, ci->i_time_warp_seq);
  }
  
  /*
   * Populate an inode based on info from mds.  May be called on new or
   * existing inodes.
   */
  static int fill_inode(struct inode *inode,
  		      struct ceph_mds_reply_info_in *iinfo,
  		      struct ceph_mds_reply_dirfrag *dirinfo,
  		      struct ceph_mds_session *session,
  		      unsigned long ttl_from, int cap_fmode,
  		      struct ceph_cap_reservation *caps_reservation)
  {
  	struct ceph_mds_reply_inode *info = iinfo->in;
  	struct ceph_inode_info *ci = ceph_inode(inode);
  	int i;

  	int issued = 0, implemented;
  	int updating_inode = 0;

  	struct timespec mtime, atime, ctime;
  	u32 nsplits;
  	struct ceph_buffer *xattr_blob = NULL;
  	int err = 0;
  	int queue_trunc = 0;
  
  	dout("fill_inode %p ino %llx.%llx v %llu had %llu
  ",
  	     inode, ceph_vinop(inode), le64_to_cpu(info->version),
  	     ci->i_version);
  
  	/*
  	 * prealloc xattr data, if it looks like we'll need it.  only
  	 * if len > 4 (meaning there are actually xattrs; the first 4
  	 * bytes are the xattr count).
  	 */
  	if (iinfo->xattr_len > 4) {

  		xattr_blob = ceph_buffer_new(iinfo->xattr_len, GFP_NOFS);

  		if (!xattr_blob)
  			pr_err("fill_inode ENOMEM xattr blob %d bytes
  ",
  			       iinfo->xattr_len);
  	}

  	spin_lock(&ci->i_ceph_lock);

  
  	/*
  	 * provided version will be odd if inode value is projected,

  	 * even if stable.  skip the update if we have newer stable
  	 * info (ours>=theirs, e.g. due to racing mds replies), unless
  	 * we are getting projected (unstable) info (in which case the
  	 * version is odd, and we want ours>theirs).
  	 *   us   them
  	 *   2    2     skip
  	 *   3    2     skip
  	 *   3    3     update

  	 */
  	if (le64_to_cpu(info->version) > 0 &&

  	    (ci->i_version & ~1) >= le64_to_cpu(info->version))

  		goto no_change;

  	
  	updating_inode = 1;

  	issued = __ceph_caps_issued(ci, &implemented);
  	issued |= implemented | __ceph_caps_dirty(ci);
  
  	/* update inode */
  	ci->i_version = le64_to_cpu(info->version);
  	inode->i_version++;
  	inode->i_rdev = le32_to_cpu(info->rdev);
  
  	if ((issued & CEPH_CAP_AUTH_EXCL) == 0) {
  		inode->i_mode = le32_to_cpu(info->mode);
  		inode->i_uid = le32_to_cpu(info->uid);
  		inode->i_gid = le32_to_cpu(info->gid);
  		dout("%p mode 0%o uid.gid %d.%d
  ", inode, inode->i_mode,
  		     inode->i_uid, inode->i_gid);
  	}
  
  	if ((issued & CEPH_CAP_LINK_EXCL) == 0)

  		set_nlink(inode, le32_to_cpu(info->nlink));

  
  	/* be careful with mtime, atime, size */
  	ceph_decode_timespec(&atime, &info->atime);
  	ceph_decode_timespec(&mtime, &info->mtime);
  	ceph_decode_timespec(&ctime, &info->ctime);
  	queue_trunc = ceph_fill_file_size(inode, issued,
  					  le32_to_cpu(info->truncate_seq),
  					  le64_to_cpu(info->truncate_size),

  					  le64_to_cpu(info->size));
  	ceph_fill_file_time(inode, issued,
  			    le32_to_cpu(info->time_warp_seq),
  			    &ctime, &mtime, &atime);

  	/* only update max_size on auth cap */
  	if ((info->cap.flags & CEPH_CAP_FLAG_AUTH) &&
  	    ci->i_max_size != le64_to_cpu(info->max_size)) {
  		dout("max_size %lld -> %llu
  ", ci->i_max_size,
  		     le64_to_cpu(info->max_size));
  		ci->i_max_size = le64_to_cpu(info->max_size);
  	}

  	ci->i_layout = info->layout;
  	inode->i_blkbits = fls(le32_to_cpu(info->layout.fl_stripe_unit)) - 1;
  
  	/* xattrs */
  	/* note that if i_xattrs.len <= 4, i_xattrs.data will still be NULL. */
  	if ((issued & CEPH_CAP_XATTR_EXCL) == 0 &&
  	    le64_to_cpu(info->xattr_version) > ci->i_xattrs.version) {
  		if (ci->i_xattrs.blob)
  			ceph_buffer_put(ci->i_xattrs.blob);
  		ci->i_xattrs.blob = xattr_blob;
  		if (xattr_blob)
  			memcpy(ci->i_xattrs.blob->vec.iov_base,
  			       iinfo->xattr_data, iinfo->xattr_len);
  		ci->i_xattrs.version = le64_to_cpu(info->xattr_version);

  		xattr_blob = NULL;

  	}
  
  	inode->i_mapping->a_ops = &ceph_aops;
  	inode->i_mapping->backing_dev_info =

  		&ceph_sb_to_client(inode->i_sb)->backing_dev_info;

  
  	switch (inode->i_mode & S_IFMT) {
  	case S_IFIFO:
  	case S_IFBLK:
  	case S_IFCHR:
  	case S_IFSOCK:
  		init_special_inode(inode, inode->i_mode, inode->i_rdev);
  		inode->i_op = &ceph_file_iops;
  		break;
  	case S_IFREG:
  		inode->i_op = &ceph_file_iops;
  		inode->i_fop = &ceph_file_fops;
  		break;
  	case S_IFLNK:
  		inode->i_op = &ceph_symlink_iops;
  		if (!ci->i_symlink) {
  			int symlen = iinfo->symlink_len;
  			char *sym;
  
  			BUG_ON(symlen != inode->i_size);

  			spin_unlock(&ci->i_ceph_lock);

  
  			err = -ENOMEM;
  			sym = kmalloc(symlen+1, GFP_NOFS);
  			if (!sym)
  				goto out;
  			memcpy(sym, iinfo->symlink, symlen);
  			sym[symlen] = 0;

  			spin_lock(&ci->i_ceph_lock);

  			if (!ci->i_symlink)
  				ci->i_symlink = sym;
  			else
  				kfree(sym); /* lost a race */
  		}
  		break;
  	case S_IFDIR:
  		inode->i_op = &ceph_dir_iops;
  		inode->i_fop = &ceph_dir_fops;

  		ci->i_dir_layout = iinfo->dir_layout;

  		ci->i_files = le64_to_cpu(info->files);
  		ci->i_subdirs = le64_to_cpu(info->subdirs);
  		ci->i_rbytes = le64_to_cpu(info->rbytes);
  		ci->i_rfiles = le64_to_cpu(info->rfiles);
  		ci->i_rsubdirs = le64_to_cpu(info->rsubdirs);
  		ceph_decode_timespec(&ci->i_rctime, &info->rctime);

  		break;
  	default:
  		pr_err("fill_inode %llx.%llx BAD mode 0%o
  ",
  		       ceph_vinop(inode), inode->i_mode);
  	}
  
  no_change:

  	spin_unlock(&ci->i_ceph_lock);

  
  	/* queue truncate if we saw i_size decrease */
  	if (queue_trunc)

  		ceph_queue_vmtruncate(inode);

  
  	/* populate frag tree */
  	/* FIXME: move me up, if/when version reflects fragtree changes */
  	nsplits = le32_to_cpu(info->fragtree.nsplits);
  	mutex_lock(&ci->i_fragtree_mutex);
  	for (i = 0; i < nsplits; i++) {
  		u32 id = le32_to_cpu(info->fragtree.splits[i].frag);
  		struct ceph_inode_frag *frag = __get_or_create_frag(ci, id);
  
  		if (IS_ERR(frag))
  			continue;
  		frag->split_by = le32_to_cpu(info->fragtree.splits[i].by);
  		dout(" frag %x split by %d
  ", frag->frag, frag->split_by);
  	}
  	mutex_unlock(&ci->i_fragtree_mutex);
  
  	/* were we issued a capability? */
  	if (info->cap.caps) {
  		if (ceph_snap(inode) == CEPH_NOSNAP) {
  			ceph_add_cap(inode, session,
  				     le64_to_cpu(info->cap.cap_id),
  				     cap_fmode,
  				     le32_to_cpu(info->cap.caps),
  				     le32_to_cpu(info->cap.wanted),
  				     le32_to_cpu(info->cap.seq),
  				     le32_to_cpu(info->cap.mseq),
  				     le64_to_cpu(info->cap.realm),
  				     info->cap.flags,
  				     caps_reservation);
  		} else {

  			spin_lock(&ci->i_ceph_lock);

  			dout(" %p got snap_caps %s
  ", inode,
  			     ceph_cap_string(le32_to_cpu(info->cap.caps)));
  			ci->i_snap_caps |= le32_to_cpu(info->cap.caps);
  			if (cap_fmode >= 0)
  				__ceph_get_fmode(ci, cap_fmode);

  			spin_unlock(&ci->i_ceph_lock);

  		}

  	} else if (cap_fmode >= 0) {
  		pr_warning("mds issued no caps on %llx.%llx
  ",
  			   ceph_vinop(inode));
  		__ceph_get_fmode(ci, cap_fmode);

  	}

  	/* set dir completion flag? */
  	if (S_ISDIR(inode->i_mode) &&
  	    updating_inode &&                 /* didn't jump to no_change */
  	    ci->i_files == 0 && ci->i_subdirs == 0 &&
  	    ceph_snap(inode) == CEPH_NOSNAP &&
  	    (le32_to_cpu(info->cap.caps) & CEPH_CAP_FILE_SHARED) &&
  	    (issued & CEPH_CAP_FILE_EXCL) == 0 &&

  	    !ceph_dir_test_complete(inode)) {

  		dout(" marking %p complete (empty)
  ", inode);

  		ceph_dir_set_complete(inode);

  		ci->i_max_offset = 2;
  	}

  	/* update delegation info? */
  	if (dirinfo)
  		ceph_fill_dirfrag(inode, dirinfo);
  
  	err = 0;
  
  out:

  	if (xattr_blob)
  		ceph_buffer_put(xattr_blob);

  	return err;
  }
  
  /*
   * caller should hold session s_mutex.
   */
  static void update_dentry_lease(struct dentry *dentry,
  				struct ceph_mds_reply_lease *lease,
  				struct ceph_mds_session *session,
  				unsigned long from_time)
  {
  	struct ceph_dentry_info *di = ceph_dentry(dentry);
  	long unsigned duration = le32_to_cpu(lease->duration_ms);
  	long unsigned ttl = from_time + (duration * HZ) / 1000;
  	long unsigned half_ttl = from_time + (duration * HZ / 2) / 1000;
  	struct inode *dir;
  
  	/* only track leases on regular dentries */
  	if (dentry->d_op != &ceph_dentry_ops)
  		return;
  
  	spin_lock(&dentry->d_lock);

  	dout("update_dentry_lease %p duration %lu ms ttl %lu
  ",
  	     dentry, duration, ttl);

  
  	/* make lease_rdcache_gen match directory */
  	dir = dentry->d_parent->d_inode;
  	di->lease_shared_gen = ceph_inode(dir)->i_shared_gen;

  	if (duration == 0)

  		goto out_unlock;
  
  	if (di->lease_gen == session->s_cap_gen &&
  	    time_before(ttl, dentry->d_time))
  		goto out_unlock;  /* we already have a newer lease. */
  
  	if (di->lease_session && di->lease_session != session)
  		goto out_unlock;
  
  	ceph_dentry_lru_touch(dentry);
  
  	if (!di->lease_session)
  		di->lease_session = ceph_get_mds_session(session);
  	di->lease_gen = session->s_cap_gen;
  	di->lease_seq = le32_to_cpu(lease->seq);
  	di->lease_renew_after = half_ttl;
  	di->lease_renew_from = 0;
  	dentry->d_time = ttl;
  out_unlock:
  	spin_unlock(&dentry->d_lock);
  	return;
  }
  
  /*

   * Set dentry's directory position based on the current dir's max, and
   * order it in d_subdirs, so that dcache_readdir behaves.

   *
   * Always called under directory's i_mutex.

   */
  static void ceph_set_dentry_offset(struct dentry *dn)
  {
  	struct dentry *dir = dn->d_parent;

  	struct inode *inode = dir->d_inode;

  	struct ceph_inode_info *ci;

  	struct ceph_dentry_info *di;
  
  	BUG_ON(!inode);

  	ci = ceph_inode(inode);

  	di = ceph_dentry(dn);

  	spin_lock(&ci->i_ceph_lock);

  	if (!ceph_dir_test_complete(inode)) {

  		spin_unlock(&ci->i_ceph_lock);

  		return;
  	}
  	di->offset = ceph_inode(inode)->i_max_offset++;

  	spin_unlock(&ci->i_ceph_lock);

  	spin_lock(&dir->d_lock);
  	spin_lock_nested(&dn->d_lock, DENTRY_D_LOCK_NESTED);

  	list_move(&dn->d_u.d_child, &dir->d_subdirs);

  	dout("set_dentry_offset %p %lld (%p %p)
  ", dn, di->offset,
  	     dn->d_u.d_child.prev, dn->d_u.d_child.next);
  	spin_unlock(&dn->d_lock);

  	spin_unlock(&dir->d_lock);

  }
  
  /*

   * splice a dentry to an inode.
   * caller must hold directory i_mutex for this to be safe.
   *
   * we will only rehash the resulting dentry if @prehash is
   * true; @prehash will be set to false (for the benefit of
   * the caller) if we fail.
   */
  static struct dentry *splice_dentry(struct dentry *dn, struct inode *in,

  				    bool *prehash, bool set_offset)

  {
  	struct dentry *realdn;

  	BUG_ON(dn->d_inode);

  	/* dn must be unhashed */
  	if (!d_unhashed(dn))
  		d_drop(dn);
  	realdn = d_materialise_unique(dn, in);
  	if (IS_ERR(realdn)) {

  		pr_err("splice_dentry error %ld %p inode %p ino %llx.%llx
  ",
  		       PTR_ERR(realdn), dn, in, ceph_vinop(in));

  		if (prehash)
  			*prehash = false; /* don't rehash on error */
  		dn = realdn; /* note realdn contains the error */
  		goto out;
  	} else if (realdn) {
  		dout("dn %p (%d) spliced with %p (%d) "
  		     "inode %p ino %llx.%llx
  ",

  		     dn, dn->d_count,
  		     realdn, realdn->d_count,

  		     realdn->d_inode, ceph_vinop(realdn->d_inode));
  		dput(dn);
  		dn = realdn;
  	} else {
  		BUG_ON(!ceph_dentry(dn));

  		dout("dn %p attached to %p ino %llx.%llx
  ",
  		     dn, dn->d_inode, ceph_vinop(dn->d_inode));
  	}
  	if ((!prehash || *prehash) && d_unhashed(dn))
  		d_rehash(dn);

  	if (set_offset)
  		ceph_set_dentry_offset(dn);

  out:
  	return dn;
  }
  
  /*
   * Incorporate results into the local cache.  This is either just
   * one inode, or a directory, dentry, and possibly linked-to inode (e.g.,
   * after a lookup).
   *
   * A reply may contain
   *         a directory inode along with a dentry.
   *  and/or a target inode
   *
   * Called with snap_rwsem (read).
   */
  int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req,
  		    struct ceph_mds_session *session)
  {
  	struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
  	struct inode *in = NULL;
  	struct ceph_mds_reply_inode *ininfo;
  	struct ceph_vino vino;

  	struct ceph_fs_client *fsc = ceph_sb_to_client(sb);

  	int i = 0;
  	int err = 0;
  
  	dout("fill_trace %p is_dentry %d is_target %d
  ", req,
  	     rinfo->head->is_dentry, rinfo->head->is_target);
  
  #if 0
  	/*
  	 * Debugging hook:
  	 *
  	 * If we resend completed ops to a recovering mds, we get no
  	 * trace.  Since that is very rare, pretend this is the case
  	 * to ensure the 'no trace' handlers in the callers behave.
  	 *
  	 * Fill in inodes unconditionally to avoid breaking cap
  	 * invariants.
  	 */
  	if (rinfo->head->op & CEPH_MDS_OP_WRITE) {
  		pr_info("fill_trace faking empty trace on %lld %s
  ",
  			req->r_tid, ceph_mds_op_name(rinfo->head->op));
  		if (rinfo->head->is_dentry) {
  			rinfo->head->is_dentry = 0;
  			err = fill_inode(req->r_locked_dir,
  					 &rinfo->diri, rinfo->dirfrag,
  					 session, req->r_request_started, -1);
  		}
  		if (rinfo->head->is_target) {
  			rinfo->head->is_target = 0;
  			ininfo = rinfo->targeti.in;
  			vino.ino = le64_to_cpu(ininfo->ino);
  			vino.snap = le64_to_cpu(ininfo->snapid);
  			in = ceph_get_inode(sb, vino);
  			err = fill_inode(in, &rinfo->targeti, NULL,
  					 session, req->r_request_started,
  					 req->r_fmode);
  			iput(in);
  		}
  	}
  #endif
  
  	if (!rinfo->head->is_target && !rinfo->head->is_dentry) {
  		dout("fill_trace reply is empty!
  ");

  		if (rinfo->head->result == 0 && req->r_locked_dir)
  			ceph_invalidate_dir_request(req);

  		return 0;
  	}
  
  	if (rinfo->head->is_dentry) {

  		struct inode *dir = req->r_locked_dir;
  
  		err = fill_inode(dir, &rinfo->diri, rinfo->dirfrag,
  				 session, req->r_request_started, -1,
  				 &req->r_caps_reservation);
  		if (err < 0)
  			return err;
  	}

  	/*
  	 * ignore null lease/binding on snapdir ENOENT, or else we
  	 * will have trouble splicing in the virtual snapdir later
  	 */
  	if (rinfo->head->is_dentry && !req->r_aborted &&
  	    (rinfo->head->is_target || strncmp(req->r_dentry->d_name.name,

  					       fsc->mount_options->snapdir_name,

  					       req->r_dentry->d_name.len))) {

  		/*
  		 * lookup link rename   : null -> possibly existing inode
  		 * mknod symlink mkdir  : null -> new inode
  		 * unlink               : linked -> null
  		 */
  		struct inode *dir = req->r_locked_dir;
  		struct dentry *dn = req->r_dentry;
  		bool have_dir_cap, have_lease;
  
  		BUG_ON(!dn);
  		BUG_ON(!dir);
  		BUG_ON(dn->d_parent->d_inode != dir);
  		BUG_ON(ceph_ino(dir) !=
  		       le64_to_cpu(rinfo->diri.in->ino));
  		BUG_ON(ceph_snap(dir) !=
  		       le64_to_cpu(rinfo->diri.in->snapid));

  		/* do we have a lease on the whole dir? */
  		have_dir_cap =
  			(le32_to_cpu(rinfo->diri.in->cap.caps) &
  			 CEPH_CAP_FILE_SHARED);
  
  		/* do we have a dn lease? */
  		have_lease = have_dir_cap ||

  			le32_to_cpu(rinfo->dlease->duration_ms);

  		if (!have_lease)
  			dout("fill_trace  no dentry lease or dir cap
  ");
  
  		/* rename? */
  		if (req->r_old_dentry && req->r_op == CEPH_MDS_OP_RENAME) {
  			dout(" src %p '%.*s' dst %p '%.*s'
  ",
  			     req->r_old_dentry,
  			     req->r_old_dentry->d_name.len,
  			     req->r_old_dentry->d_name.name,
  			     dn, dn->d_name.len, dn->d_name.name);
  			dout("fill_trace doing d_move %p -> %p
  ",
  			     req->r_old_dentry, dn);

  			d_move(req->r_old_dentry, dn);
  			dout(" src %p '%.*s' dst %p '%.*s'
  ",
  			     req->r_old_dentry,
  			     req->r_old_dentry->d_name.len,
  			     req->r_old_dentry->d_name.name,
  			     dn, dn->d_name.len, dn->d_name.name);

  			/* ensure target dentry is invalidated, despite
  			   rehashing bug in vfs_rename_dir */

  			ceph_invalidate_dentry_lease(dn);

  			/*
  			 * d_move() puts the renamed dentry at the end of
  			 * d_subdirs.  We need to assign it an appropriate
  			 * directory offset so we can behave when holding

  			 * D_COMPLETE.

  			 */
  			ceph_set_dentry_offset(req->r_old_dentry);
  			dout("dn %p gets new offset %lld
  ", req->r_old_dentry, 

  			     ceph_dentry(req->r_old_dentry)->offset);

  			dn = req->r_old_dentry;  /* use old_dentry */
  			in = dn->d_inode;
  		}
  
  		/* null dentry? */
  		if (!rinfo->head->is_target) {
  			dout("fill_trace null dentry
  ");
  			if (dn->d_inode) {
  				dout("d_delete %p
  ", dn);
  				d_delete(dn);
  			} else {
  				dout("d_instantiate %p NULL
  ", dn);
  				d_instantiate(dn, NULL);
  				if (have_lease && d_unhashed(dn))
  					d_rehash(dn);
  				update_dentry_lease(dn, rinfo->dlease,
  						    session,
  						    req->r_request_started);
  			}
  			goto done;
  		}
  
  		/* attach proper inode */
  		ininfo = rinfo->targeti.in;
  		vino.ino = le64_to_cpu(ininfo->ino);
  		vino.snap = le64_to_cpu(ininfo->snapid);

  		in = dn->d_inode;
  		if (!in) {

  			in = ceph_get_inode(sb, vino);
  			if (IS_ERR(in)) {
  				pr_err("fill_trace bad get_inode "
  				       "%llx.%llx
  ", vino.ino, vino.snap);
  				err = PTR_ERR(in);
  				d_delete(dn);
  				goto done;
  			}

  			dn = splice_dentry(dn, in, &have_lease, true);

  			if (IS_ERR(dn)) {
  				err = PTR_ERR(dn);
  				goto done;
  			}
  			req->r_dentry = dn;  /* may have spliced */

  			ihold(in);

  		} else if (ceph_ino(in) == vino.ino &&
  			   ceph_snap(in) == vino.snap) {

  			ihold(in);

  		} else {
  			dout(" %p links to %p %llx.%llx, not %llx.%llx
  ",
  			     dn, in, ceph_ino(in), ceph_snap(in),
  			     vino.ino, vino.snap);
  			have_lease = false;
  			in = NULL;
  		}
  
  		if (have_lease)
  			update_dentry_lease(dn, rinfo->dlease, session,
  					    req->r_request_started);
  		dout(" final dn %p
  ", dn);
  		i++;
  	} else if (req->r_op == CEPH_MDS_OP_LOOKUPSNAP ||
  		   req->r_op == CEPH_MDS_OP_MKSNAP) {
  		struct dentry *dn = req->r_dentry;
  
  		/* fill out a snapdir LOOKUPSNAP dentry */
  		BUG_ON(!dn);
  		BUG_ON(!req->r_locked_dir);
  		BUG_ON(ceph_snap(req->r_locked_dir) != CEPH_SNAPDIR);
  		ininfo = rinfo->targeti.in;
  		vino.ino = le64_to_cpu(ininfo->ino);
  		vino.snap = le64_to_cpu(ininfo->snapid);
  		in = ceph_get_inode(sb, vino);
  		if (IS_ERR(in)) {
  			pr_err("fill_inode get_inode badness %llx.%llx
  ",
  			       vino.ino, vino.snap);
  			err = PTR_ERR(in);
  			d_delete(dn);
  			goto done;
  		}
  		dout(" linking snapped dir %p to dn %p
  ", in, dn);

  		dn = splice_dentry(dn, in, NULL, true);

  		if (IS_ERR(dn)) {
  			err = PTR_ERR(dn);
  			goto done;
  		}
  		req->r_dentry = dn;  /* may have spliced */

  		ihold(in);

  		rinfo->head->is_dentry = 1;  /* fool notrace handlers */
  	}
  
  	if (rinfo->head->is_target) {
  		vino.ino = le64_to_cpu(rinfo->targeti.in->ino);
  		vino.snap = le64_to_cpu(rinfo->targeti.in->snapid);
  
  		if (in == NULL || ceph_ino(in) != vino.ino ||
  		    ceph_snap(in) != vino.snap) {
  			in = ceph_get_inode(sb, vino);
  			if (IS_ERR(in)) {
  				err = PTR_ERR(in);
  				goto done;
  			}
  		}
  		req->r_target_inode = in;
  
  		err = fill_inode(in,
  				 &rinfo->targeti, NULL,
  				 session, req->r_request_started,
  				 (le32_to_cpu(rinfo->head->result) == 0) ?
  				 req->r_fmode : -1,
  				 &req->r_caps_reservation);
  		if (err < 0) {
  			pr_err("fill_inode badness %p %llx.%llx
  ",
  			       in, ceph_vinop(in));
  			goto done;
  		}
  	}
  
  done:
  	dout("fill_trace done err=%d
  ", err);
  	return err;
  }
  
  /*
   * Prepopulate our cache with readdir results, leases, etc.
   */
  int ceph_readdir_prepopulate(struct ceph_mds_request *req,
  			     struct ceph_mds_session *session)
  {
  	struct dentry *parent = req->r_dentry;
  	struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
  	struct qstr dname;
  	struct dentry *dn;
  	struct inode *in;
  	int err = 0, i;
  	struct inode *snapdir = NULL;
  	struct ceph_mds_request_head *rhead = req->r_request->front.iov_base;
  	u64 frag = le32_to_cpu(rhead->args.readdir.frag);
  	struct ceph_dentry_info *di;
  
  	if (le32_to_cpu(rinfo->head->op) == CEPH_MDS_OP_LSSNAP) {
  		snapdir = ceph_get_snapdir(parent->d_inode);
  		parent = d_find_alias(snapdir);
  		dout("readdir_prepopulate %d items under SNAPDIR dn %p
  ",
  		     rinfo->dir_nr, parent);
  	} else {
  		dout("readdir_prepopulate %d items under dn %p
  ",
  		     rinfo->dir_nr, parent);
  		if (rinfo->dir_dir)
  			ceph_fill_dirfrag(parent->d_inode, rinfo->dir_dir);
  	}
  
  	for (i = 0; i < rinfo->dir_nr; i++) {
  		struct ceph_vino vino;
  
  		dname.name = rinfo->dir_dname[i];
  		dname.len = rinfo->dir_dname_len[i];
  		dname.hash = full_name_hash(dname.name, dname.len);
  
  		vino.ino = le64_to_cpu(rinfo->dir_in[i].in->ino);
  		vino.snap = le64_to_cpu(rinfo->dir_in[i].in->snapid);
  
  retry_lookup:
  		dn = d_lookup(parent, &dname);
  		dout("d_lookup on parent=%p name=%.*s got %p
  ",
  		     parent, dname.len, dname.name, dn);
  
  		if (!dn) {
  			dn = d_alloc(parent, &dname);
  			dout("d_alloc %p '%.*s' = %p
  ", parent,
  			     dname.len, dname.name, dn);
  			if (dn == NULL) {
  				dout("d_alloc badness
  ");
  				err = -ENOMEM;
  				goto out;
  			}
  			err = ceph_init_dentry(dn);

  			if (err < 0) {
  				dput(dn);

  				goto out;

  			}

  		} else if (dn->d_inode &&
  			   (ceph_ino(dn->d_inode) != vino.ino ||
  			    ceph_snap(dn->d_inode) != vino.snap)) {
  			dout(" dn %p points to wrong inode %p
  ",
  			     dn, dn->d_inode);
  			d_delete(dn);
  			dput(dn);
  			goto retry_lookup;
  		} else {
  			/* reorder parent's d_subdirs */

  			spin_lock(&parent->d_lock);
  			spin_lock_nested(&dn->d_lock, DENTRY_D_LOCK_NESTED);

  			list_move(&dn->d_u.d_child, &parent->d_subdirs);
  			spin_unlock(&dn->d_lock);

  			spin_unlock(&parent->d_lock);

  		}
  
  		di = dn->d_fsdata;
  		di->offset = ceph_make_fpos(frag, i + req->r_readdir_offset);
  
  		/* inode */
  		if (dn->d_inode) {
  			in = dn->d_inode;
  		} else {
  			in = ceph_get_inode(parent->d_sb, vino);

  			if (IS_ERR(in)) {

  				dout("new_inode badness
  ");
  				d_delete(dn);
  				dput(dn);

  				err = PTR_ERR(in);

  				goto out;
  			}

  			dn = splice_dentry(dn, in, NULL, false);

  			if (IS_ERR(dn))
  				dn = NULL;

  		}
  
  		if (fill_inode(in, &rinfo->dir_in[i], NULL, session,
  			       req->r_request_started, -1,
  			       &req->r_caps_reservation) < 0) {
  			pr_err("fill_inode badness on %p
  ", in);

  			goto next_item;

  		}

  		if (dn)
  			update_dentry_lease(dn, rinfo->dir_dlease[i],
  					    req->r_session,
  					    req->r_request_started);
  next_item:
  		if (dn)
  			dput(dn);

  	}
  	req->r_did_prepopulate = true;
  
  out:
  	if (snapdir) {
  		iput(snapdir);
  		dput(parent);
  	}
  	dout("readdir_prepopulate done
  ");
  	return err;
  }
  
  int ceph_inode_set_size(struct inode *inode, loff_t size)
  {
  	struct ceph_inode_info *ci = ceph_inode(inode);
  	int ret = 0;

  	spin_lock(&ci->i_ceph_lock);

  	dout("set_size %p %llu -> %llu
  ", inode, inode->i_size, size);
  	inode->i_size = size;
  	inode->i_blocks = (size + (1 << 9) - 1) >> 9;
  
  	/* tell the MDS if we are approaching max_size */
  	if ((size << 1) >= ci->i_max_size &&
  	    (ci->i_reported_size << 1) < ci->i_max_size)
  		ret = 1;

  	spin_unlock(&ci->i_ceph_lock);

  	return ret;
  }
  
  /*
   * Write back inode data in a worker thread.  (This can't be done
   * in the message handler context.)
   */

  void ceph_queue_writeback(struct inode *inode)
  {

  	ihold(inode);

  	if (queue_work(ceph_inode_to_client(inode)->wb_wq,
  		       &ceph_inode(inode)->i_wb_work)) {

  		dout("ceph_queue_writeback %p
  ", inode);

  	} else {

  		dout("ceph_queue_writeback %p failed
  ", inode);

  		iput(inode);

  	}
  }
  
  static void ceph_writeback_work(struct work_struct *work)

  {
  	struct ceph_inode_info *ci = container_of(work, struct ceph_inode_info,
  						  i_wb_work);
  	struct inode *inode = &ci->vfs_inode;
  
  	dout("writeback %p
  ", inode);
  	filemap_fdatawrite(&inode->i_data);
  	iput(inode);
  }
  
  /*

   * queue an async invalidation
   */
  void ceph_queue_invalidate(struct inode *inode)
  {

  	ihold(inode);

  	if (queue_work(ceph_inode_to_client(inode)->pg_inv_wq,
  		       &ceph_inode(inode)->i_pg_inv_work)) {
  		dout("ceph_queue_invalidate %p
  ", inode);

  	} else {
  		dout("ceph_queue_invalidate %p failed
  ", inode);

  		iput(inode);

  	}
  }
  
  /*

   * Invalidate inode pages in a worker thread.  (This can't be done
   * in the message handler context.)
   */

  static void ceph_invalidate_work(struct work_struct *work)

  {
  	struct ceph_inode_info *ci = container_of(work, struct ceph_inode_info,
  						  i_pg_inv_work);
  	struct inode *inode = &ci->vfs_inode;
  	u32 orig_gen;
  	int check = 0;

  	spin_lock(&ci->i_ceph_lock);

  	dout("invalidate_pages %p gen %d revoking %d
  ", inode,
  	     ci->i_rdcache_gen, ci->i_rdcache_revoking);

  	if (ci->i_rdcache_revoking != ci->i_rdcache_gen) {

  		/* nevermind! */

  		spin_unlock(&ci->i_ceph_lock);

  		goto out;
  	}
  	orig_gen = ci->i_rdcache_gen;

  	spin_unlock(&ci->i_ceph_lock);

  	truncate_inode_pages(&inode->i_data, 0);

  	spin_lock(&ci->i_ceph_lock);

  	if (orig_gen == ci->i_rdcache_gen &&
  	    orig_gen == ci->i_rdcache_revoking) {

  		dout("invalidate_pages %p gen %d successful
  ", inode,
  		     ci->i_rdcache_gen);

  		ci->i_rdcache_revoking--;

  		check = 1;
  	} else {

  		dout("invalidate_pages %p gen %d raced, now %d revoking %d
  ",
  		     inode, orig_gen, ci->i_rdcache_gen,
  		     ci->i_rdcache_revoking);

  	}

  	spin_unlock(&ci->i_ceph_lock);

  
  	if (check)
  		ceph_check_caps(ci, 0, NULL);
  out:
  	iput(inode);
  }
  
  
  /*
   * called by trunc_wq; take i_mutex ourselves
   *
   * We also truncate in a separate thread as well.
   */

  static void ceph_vmtruncate_work(struct work_struct *work)

  {
  	struct ceph_inode_info *ci = container_of(work, struct ceph_inode_info,
  						  i_vmtruncate_work);
  	struct inode *inode = &ci->vfs_inode;
  
  	dout("vmtruncate_work %p
  ", inode);
  	mutex_lock(&inode->i_mutex);
  	__ceph_do_pending_vmtruncate(inode);
  	mutex_unlock(&inode->i_mutex);
  	iput(inode);
  }
  
  /*

   * Queue an async vmtruncate.  If we fail to queue work, we will handle
   * the truncation the next time we call __ceph_do_pending_vmtruncate.
   */
  void ceph_queue_vmtruncate(struct inode *inode)
  {
  	struct ceph_inode_info *ci = ceph_inode(inode);

  	ihold(inode);

  	if (queue_work(ceph_sb_to_client(inode->i_sb)->trunc_wq,

  		       &ci->i_vmtruncate_work)) {
  		dout("ceph_queue_vmtruncate %p
  ", inode);

  	} else {
  		dout("ceph_queue_vmtruncate %p failed, pending=%d
  ",
  		     inode, ci->i_truncate_pending);

  		iput(inode);

  	}
  }
  
  /*

   * called with i_mutex held.
   *
   * Make sure any pending truncation is applied before doing anything
   * that may depend on it.
   */
  void __ceph_do_pending_vmtruncate(struct inode *inode)
  {
  	struct ceph_inode_info *ci = ceph_inode(inode);
  	u64 to;
  	int wrbuffer_refs, wake = 0;
  
  retry:

  	spin_lock(&ci->i_ceph_lock);

  	if (ci->i_truncate_pending == 0) {
  		dout("__do_pending_vmtruncate %p none pending
  ", inode);

  		spin_unlock(&ci->i_ceph_lock);

  		return;
  	}
  
  	/*
  	 * make sure any dirty snapped pages are flushed before we
  	 * possibly truncate them.. so write AND block!
  	 */
  	if (ci->i_wrbuffer_ref_head < ci->i_wrbuffer_ref) {
  		dout("__do_pending_vmtruncate %p flushing snaps first
  ",
  		     inode);

  		spin_unlock(&ci->i_ceph_lock);

  		filemap_write_and_wait_range(&inode->i_data, 0,
  					     inode->i_sb->s_maxbytes);
  		goto retry;
  	}
  
  	to = ci->i_truncate_size;
  	wrbuffer_refs = ci->i_wrbuffer_ref;
  	dout("__do_pending_vmtruncate %p (%d) to %lld
  ", inode,
  	     ci->i_truncate_pending, to);

  	spin_unlock(&ci->i_ceph_lock);

  
  	truncate_inode_pages(inode->i_mapping, to);

  	spin_lock(&ci->i_ceph_lock);

  	ci->i_truncate_pending--;
  	if (ci->i_truncate_pending == 0)
  		wake = 1;

  	spin_unlock(&ci->i_ceph_lock);

  
  	if (wrbuffer_refs == 0)
  		ceph_check_caps(ci, CHECK_CAPS_AUTHONLY, NULL);
  	if (wake)

  		wake_up_all(&ci->i_cap_wq);

  }
  
  
  /*
   * symlinks
   */
  static void *ceph_sym_follow_link(struct dentry *dentry, struct nameidata *nd)
  {
  	struct ceph_inode_info *ci = ceph_inode(dentry->d_inode);
  	nd_set_link(nd, ci->i_symlink);
  	return NULL;
  }
  
  static const struct inode_operations ceph_symlink_iops = {
  	.readlink = generic_readlink,
  	.follow_link = ceph_sym_follow_link,
  };
  
  /*
   * setattr
   */
  int ceph_setattr(struct dentry *dentry, struct iattr *attr)
  {
  	struct inode *inode = dentry->d_inode;
  	struct ceph_inode_info *ci = ceph_inode(inode);

  	struct inode *parent_inode;

  	const unsigned int ia_valid = attr->ia_valid;
  	struct ceph_mds_request *req;

  	struct ceph_mds_client *mdsc = ceph_sb_to_client(dentry->d_sb)->mdsc;

  	int issued;
  	int release = 0, dirtied = 0;
  	int mask = 0;
  	int err = 0;

  	int inode_dirty_flags = 0;

  
  	if (ceph_snap(inode) != CEPH_NOSNAP)
  		return -EROFS;
  
  	__ceph_do_pending_vmtruncate(inode);
  
  	err = inode_change_ok(inode, attr);
  	if (err != 0)
  		return err;
  
  	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SETATTR,
  				       USE_AUTH_MDS);
  	if (IS_ERR(req))
  		return PTR_ERR(req);

  	spin_lock(&ci->i_ceph_lock);

  	issued = __ceph_caps_issued(ci, NULL);
  	dout("setattr %p issued %s
  ", inode, ceph_cap_string(issued));
  
  	if (ia_valid & ATTR_UID) {
  		dout("setattr %p uid %d -> %d
  ", inode,
  		     inode->i_uid, attr->ia_uid);
  		if (issued & CEPH_CAP_AUTH_EXCL) {
  			inode->i_uid = attr->ia_uid;
  			dirtied |= CEPH_CAP_AUTH_EXCL;
  		} else if ((issued & CEPH_CAP_AUTH_SHARED) == 0 ||
  			   attr->ia_uid != inode->i_uid) {
  			req->r_args.setattr.uid = cpu_to_le32(attr->ia_uid);
  			mask |= CEPH_SETATTR_UID;
  			release |= CEPH_CAP_AUTH_SHARED;
  		}
  	}
  	if (ia_valid & ATTR_GID) {
  		dout("setattr %p gid %d -> %d
  ", inode,
  		     inode->i_gid, attr->ia_gid);
  		if (issued & CEPH_CAP_AUTH_EXCL) {
  			inode->i_gid = attr->ia_gid;
  			dirtied |= CEPH_CAP_AUTH_EXCL;
  		} else if ((issued & CEPH_CAP_AUTH_SHARED) == 0 ||
  			   attr->ia_gid != inode->i_gid) {
  			req->r_args.setattr.gid = cpu_to_le32(attr->ia_gid);
  			mask |= CEPH_SETATTR_GID;
  			release |= CEPH_CAP_AUTH_SHARED;
  		}
  	}
  	if (ia_valid & ATTR_MODE) {
  		dout("setattr %p mode 0%o -> 0%o
  ", inode, inode->i_mode,
  		     attr->ia_mode);
  		if (issued & CEPH_CAP_AUTH_EXCL) {
  			inode->i_mode = attr->ia_mode;
  			dirtied |= CEPH_CAP_AUTH_EXCL;
  		} else if ((issued & CEPH_CAP_AUTH_SHARED) == 0 ||
  			   attr->ia_mode != inode->i_mode) {
  			req->r_args.setattr.mode = cpu_to_le32(attr->ia_mode);
  			mask |= CEPH_SETATTR_MODE;
  			release |= CEPH_CAP_AUTH_SHARED;
  		}
  	}
  
  	if (ia_valid & ATTR_ATIME) {
  		dout("setattr %p atime %ld.%ld -> %ld.%ld
  ", inode,
  		     inode->i_atime.tv_sec, inode->i_atime.tv_nsec,
  		     attr->ia_atime.tv_sec, attr->ia_atime.tv_nsec);
  		if (issued & CEPH_CAP_FILE_EXCL) {
  			ci->i_time_warp_seq++;
  			inode->i_atime = attr->ia_atime;
  			dirtied |= CEPH_CAP_FILE_EXCL;
  		} else if ((issued & CEPH_CAP_FILE_WR) &&
  			   timespec_compare(&inode->i_atime,
  					    &attr->ia_atime) < 0) {
  			inode->i_atime = attr->ia_atime;
  			dirtied |= CEPH_CAP_FILE_WR;
  		} else if ((issued & CEPH_CAP_FILE_SHARED) == 0 ||
  			   !timespec_equal(&inode->i_atime, &attr->ia_atime)) {
  			ceph_encode_timespec(&req->r_args.setattr.atime,
  					     &attr->ia_atime);
  			mask |= CEPH_SETATTR_ATIME;
  			release |= CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_RD |
  				CEPH_CAP_FILE_WR;
  		}
  	}
  	if (ia_valid & ATTR_MTIME) {
  		dout("setattr %p mtime %ld.%ld -> %ld.%ld
  ", inode,
  		     inode->i_mtime.tv_sec, inode->i_mtime.tv_nsec,
  		     attr->ia_mtime.tv_sec, attr->ia_mtime.tv_nsec);
  		if (issued & CEPH_CAP_FILE_EXCL) {
  			ci->i_time_warp_seq++;
  			inode->i_mtime = attr->ia_mtime;
  			dirtied |= CEPH_CAP_FILE_EXCL;
  		} else if ((issued & CEPH_CAP_FILE_WR) &&
  			   timespec_compare(&inode->i_mtime,
  					    &attr->ia_mtime) < 0) {
  			inode->i_mtime = attr->ia_mtime;
  			dirtied |= CEPH_CAP_FILE_WR;
  		} else if ((issued & CEPH_CAP_FILE_SHARED) == 0 ||
  			   !timespec_equal(&inode->i_mtime, &attr->ia_mtime)) {
  			ceph_encode_timespec(&req->r_args.setattr.mtime,
  					     &attr->ia_mtime);
  			mask |= CEPH_SETATTR_MTIME;
  			release |= CEPH_CAP_FILE_SHARED | CEPH_CAP_FILE_RD |
  				CEPH_CAP_FILE_WR;
  		}
  	}
  	if (ia_valid & ATTR_SIZE) {
  		dout("setattr %p size %lld -> %lld
  ", inode,
  		     inode->i_size, attr->ia_size);
  		if (attr->ia_size > inode->i_sb->s_maxbytes) {
  			err = -EINVAL;
  			goto out;
  		}
  		if ((issued & CEPH_CAP_FILE_EXCL) &&
  		    attr->ia_size > inode->i_size) {
  			inode->i_size = attr->ia_size;

  			inode->i_blocks =
  				(attr->ia_size + (1 << 9) - 1) >> 9;
  			inode->i_ctime = attr->ia_ctime;
  			ci->i_reported_size = attr->ia_size;
  			dirtied |= CEPH_CAP_FILE_EXCL;
  		} else if ((issued & CEPH_CAP_FILE_SHARED) == 0 ||
  			   attr->ia_size != inode->i_size) {
  			req->r_args.setattr.size = cpu_to_le64(attr->ia_size);
  			req->r_args.setattr.old_size =
  				cpu_to_le64(inode->i_size);
  			mask |= CEPH_SETATTR_SIZE;
  			release |= CEPH_CAP_FILE_SHARED | CEPH_CAP_FILE_RD |
  				CEPH_CAP_FILE_WR;
  		}
  	}
  
  	/* these do nothing */
  	if (ia_valid & ATTR_CTIME) {
  		bool only = (ia_valid & (ATTR_SIZE|ATTR_MTIME|ATTR_ATIME|
  					 ATTR_MODE|ATTR_UID|ATTR_GID)) == 0;
  		dout("setattr %p ctime %ld.%ld -> %ld.%ld (%s)
  ", inode,
  		     inode->i_ctime.tv_sec, inode->i_ctime.tv_nsec,
  		     attr->ia_ctime.tv_sec, attr->ia_ctime.tv_nsec,
  		     only ? "ctime only" : "ignored");
  		inode->i_ctime = attr->ia_ctime;
  		if (only) {
  			/*
  			 * if kernel wants to dirty ctime but nothing else,
  			 * we need to choose a cap to dirty under, or do
  			 * a almost-no-op setattr
  			 */
  			if (issued & CEPH_CAP_AUTH_EXCL)
  				dirtied |= CEPH_CAP_AUTH_EXCL;
  			else if (issued & CEPH_CAP_FILE_EXCL)
  				dirtied |= CEPH_CAP_FILE_EXCL;
  			else if (issued & CEPH_CAP_XATTR_EXCL)
  				dirtied |= CEPH_CAP_XATTR_EXCL;
  			else
  				mask |= CEPH_SETATTR_CTIME;
  		}
  	}
  	if (ia_valid & ATTR_FILE)
  		dout("setattr %p ATTR_FILE ... hrm!
  ", inode);
  
  	if (dirtied) {

  		inode_dirty_flags = __ceph_mark_dirty_caps(ci, dirtied);

  		inode->i_ctime = CURRENT_TIME;
  	}
  
  	release &= issued;

  	spin_unlock(&ci->i_ceph_lock);

  	if (inode_dirty_flags)
  		__mark_inode_dirty(inode, inode_dirty_flags);

  	if (mask) {

  		req->r_inode = inode;
  		ihold(inode);

  		req->r_inode_drop = release;
  		req->r_args.setattr.mask = cpu_to_le32(mask);
  		req->r_num_caps = 1;

  		parent_inode = ceph_get_dentry_parent_inode(dentry);

  		err = ceph_mdsc_do_request(mdsc, parent_inode, req);

  		iput(parent_inode);

  	}
  	dout("setattr %p result=%d (%s locally, %d remote)
  ", inode, err,
  	     ceph_cap_string(dirtied), mask);
  
  	ceph_mdsc_put_request(req);
  	__ceph_do_pending_vmtruncate(inode);
  	return err;
  out:

  	spin_unlock(&ci->i_ceph_lock);

  	ceph_mdsc_put_request(req);
  	return err;
  }
  
  /*
   * Verify that we have a lease on the given mask.  If not,
   * do a getattr against an mds.
   */
  int ceph_do_getattr(struct inode *inode, int mask)
  {

  	struct ceph_fs_client *fsc = ceph_sb_to_client(inode->i_sb);
  	struct ceph_mds_client *mdsc = fsc->mdsc;

  	struct ceph_mds_request *req;
  	int err;
  
  	if (ceph_snap(inode) == CEPH_SNAPDIR) {
  		dout("do_getattr inode %p SNAPDIR
  ", inode);
  		return 0;
  	}

  	dout("do_getattr inode %p mask %s mode 0%o
  ", inode, ceph_cap_string(mask), inode->i_mode);

  	if (ceph_caps_issued_mask(ceph_inode(inode), mask, 1))
  		return 0;
  
  	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_GETATTR, USE_ANY_MDS);
  	if (IS_ERR(req))
  		return PTR_ERR(req);

  	req->r_inode = inode;
  	ihold(inode);

  	req->r_num_caps = 1;
  	req->r_args.getattr.mask = cpu_to_le32(mask);
  	err = ceph_mdsc_do_request(mdsc, NULL, req);
  	ceph_mdsc_put_request(req);
  	dout("do_getattr result=%d
  ", err);
  	return err;
  }
  
  
  /*
   * Check inode permissions.  We verify we have a valid value for
   * the AUTH cap, then call the generic handler.
   */

  int ceph_permission(struct inode *inode, int mask)

  {

  	int err;

  	if (mask & MAY_NOT_BLOCK)

  		return -ECHILD;
  
  	err = ceph_do_getattr(inode, CEPH_CAP_AUTH_SHARED);

  
  	if (!err)

  		err = generic_permission(inode, mask);

  	return err;
  }
  
  /*
   * Get all attributes.  Hopefully somedata we'll have a statlite()
   * and can limit the fields we require to be accurate.
   */
  int ceph_getattr(struct vfsmount *mnt, struct dentry *dentry,
  		 struct kstat *stat)
  {
  	struct inode *inode = dentry->d_inode;

  	struct ceph_inode_info *ci = ceph_inode(inode);

  	int err;
  
  	err = ceph_do_getattr(inode, CEPH_STAT_CAP_INODE_ALL);
  	if (!err) {
  		generic_fillattr(inode, stat);

  		stat->ino = ceph_translate_ino(inode->i_sb, inode->i_ino);

  		if (ceph_snap(inode) != CEPH_NOSNAP)
  			stat->dev = ceph_snap(inode);
  		else
  			stat->dev = 0;

  		if (S_ISDIR(inode->i_mode)) {

  			if (ceph_test_mount_opt(ceph_sb_to_client(inode->i_sb),
  						RBYTES))
  				stat->size = ci->i_rbytes;
  			else
  				stat->size = ci->i_files + ci->i_subdirs;

  			stat->blocks = 0;

  			stat->blksize = 65536;

  		}

  	}
  	return err;
  }