/*
   * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   * Copyright (C) 2004-2008 Red Hat, Inc.  All rights reserved.
   *
   * This copyrighted material is made available to anyone wishing to use,
   * modify, copy, or redistribute it subject to the terms and conditions
   * of the GNU General Public License version 2.
   */
  
  #include <linux/spinlock.h>
  #include <linux/completion.h>
  #include <linux/buffer_head.h>
  #include <linux/gfs2_ondisk.h>
  #include <linux/bio.h>
  #include <linux/posix_acl.h>
  
  #include "gfs2.h"
  #include "incore.h"
  #include "bmap.h"
  #include "glock.h"
  #include "glops.h"
  #include "inode.h"
  #include "log.h"
  #include "meta_io.h"
  #include "recovery.h"
  #include "rgrp.h"
  #include "util.h"
  #include "trans.h"
  #include "dir.h"
  
  struct workqueue_struct *gfs2_freeze_wq;
  
  static void gfs2_ail_error(struct gfs2_glock *gl, const struct buffer_head *bh)
  {
  	fs_err(gl->gl_name.ln_sbd,
  	       "AIL buffer %p: blocknr %llu state 0x%08lx mapping %p page "
  	       "state 0x%lx
  ",
  	       bh, (unsigned long long)bh->b_blocknr, bh->b_state,
  	       bh->b_page->mapping, bh->b_page->flags);
  	fs_err(gl->gl_name.ln_sbd, "AIL glock %u:%llu mapping %p
  ",
  	       gl->gl_name.ln_type, gl->gl_name.ln_number,
  	       gfs2_glock2aspace(gl));
  	gfs2_lm_withdraw(gl->gl_name.ln_sbd, "AIL error
  ");
  }
  
  /**
   * __gfs2_ail_flush - remove all buffers for a given lock from the AIL
   * @gl: the glock
   * @fsync: set when called from fsync (not all buffers will be clean)
   *
   * None of the buffers should be dirty, locked, or pinned.
   */
  
  static void __gfs2_ail_flush(struct gfs2_glock *gl, bool fsync,
  			     unsigned int nr_revokes)
  {
  	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
  	struct list_head *head = &gl->gl_ail_list;
  	struct gfs2_bufdata *bd, *tmp;
  	struct buffer_head *bh;
  	const unsigned long b_state = (1UL << BH_Dirty)|(1UL << BH_Pinned)|(1UL << BH_Lock);
  
  	gfs2_log_lock(sdp);
  	spin_lock(&sdp->sd_ail_lock);
  	list_for_each_entry_safe_reverse(bd, tmp, head, bd_ail_gl_list) {
  		if (nr_revokes == 0)
  			break;
  		bh = bd->bd_bh;
  		if (bh->b_state & b_state) {
  			if (fsync)
  				continue;
  			gfs2_ail_error(gl, bh);
  		}
  		gfs2_trans_add_revoke(sdp, bd);
  		nr_revokes--;
  	}
  	GLOCK_BUG_ON(gl, !fsync && atomic_read(&gl->gl_ail_count));
  	spin_unlock(&sdp->sd_ail_lock);
  	gfs2_log_unlock(sdp);
  }
  
  
  static void gfs2_ail_empty_gl(struct gfs2_glock *gl)
  {
  	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
  	struct gfs2_trans tr;
  
  	memset(&tr, 0, sizeof(tr));
  	INIT_LIST_HEAD(&tr.tr_buf);
  	INIT_LIST_HEAD(&tr.tr_databuf);
  	tr.tr_revokes = atomic_read(&gl->gl_ail_count);
  
  	if (!tr.tr_revokes)
  		return;
  
  	/* A shortened, inline version of gfs2_trans_begin()
           * tr->alloced is not set since the transaction structure is
           * on the stack */
  	tr.tr_reserved = 1 + gfs2_struct2blk(sdp, tr.tr_revokes, sizeof(u64));
  	tr.tr_ip = _RET_IP_;
  	if (gfs2_log_reserve(sdp, tr.tr_reserved) < 0)
  		return;
  	WARN_ON_ONCE(current->journal_info);
  	current->journal_info = &tr;
  
  	__gfs2_ail_flush(gl, 0, tr.tr_revokes);
  
  	gfs2_trans_end(sdp);
  	gfs2_log_flush(sdp, NULL, NORMAL_FLUSH);
  }
  
  void gfs2_ail_flush(struct gfs2_glock *gl, bool fsync)
  {
  	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
  	unsigned int revokes = atomic_read(&gl->gl_ail_count);
  	unsigned int max_revokes = (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_log_descriptor)) / sizeof(u64);
  	int ret;
  
  	if (!revokes)
  		return;
  
  	while (revokes > max_revokes)
  		max_revokes += (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_meta_header)) / sizeof(u64);
  
  	ret = gfs2_trans_begin(sdp, 0, max_revokes);
  	if (ret)
  		return;
  	__gfs2_ail_flush(gl, fsync, max_revokes);
  	gfs2_trans_end(sdp);
  	gfs2_log_flush(sdp, NULL, NORMAL_FLUSH);
  }
  
  /**
   * rgrp_go_sync - sync out the metadata for this glock
   * @gl: the glock
   *
   * Called when demoting or unlocking an EX glock.  We must flush
   * to disk all dirty buffers/pages relating to this glock, and must not
   * not return to caller to demote/unlock the glock until I/O is complete.
   */
  
  static void rgrp_go_sync(struct gfs2_glock *gl)
  {
  	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
  	struct address_space *mapping = &sdp->sd_aspace;
  	struct gfs2_rgrpd *rgd;
  	int error;
  
  	spin_lock(&gl->gl_lockref.lock);
  	rgd = gl->gl_object;
  	if (rgd)
  		gfs2_rgrp_brelse(rgd);
  	spin_unlock(&gl->gl_lockref.lock);
  
  	if (!test_and_clear_bit(GLF_DIRTY, &gl->gl_flags))
  		return;
  	GLOCK_BUG_ON(gl, gl->gl_state != LM_ST_EXCLUSIVE);
  
  	gfs2_log_flush(sdp, gl, NORMAL_FLUSH);
  	filemap_fdatawrite_range(mapping, gl->gl_vm.start, gl->gl_vm.end);
  	error = filemap_fdatawait_range(mapping, gl->gl_vm.start, gl->gl_vm.end);
  	mapping_set_error(mapping, error);
  	gfs2_ail_empty_gl(gl);
  
  	spin_lock(&gl->gl_lockref.lock);
  	rgd = gl->gl_object;
  	if (rgd)
  		gfs2_free_clones(rgd);
  	spin_unlock(&gl->gl_lockref.lock);
  }
  
  /**
   * rgrp_go_inval - invalidate the metadata for this glock
   * @gl: the glock
   * @flags:
   *
   * We never used LM_ST_DEFERRED with resource groups, so that we
   * should always see the metadata flag set here.
   *
   */
  
  static void rgrp_go_inval(struct gfs2_glock *gl, int flags)
  {
  	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
  	struct address_space *mapping = &sdp->sd_aspace;
  	struct gfs2_rgrpd *rgd = gl->gl_object;
  
  	if (rgd)
  		gfs2_rgrp_brelse(rgd);
  
  	WARN_ON_ONCE(!(flags & DIO_METADATA));
  	gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));
  	truncate_inode_pages_range(mapping, gl->gl_vm.start, gl->gl_vm.end);
  
  	if (rgd)
  		rgd->rd_flags &= ~GFS2_RDF_UPTODATE;
  }
  
  /**
   * inode_go_sync - Sync the dirty data and/or metadata for an inode glock
   * @gl: the glock protecting the inode
   *
   */
  
  static void inode_go_sync(struct gfs2_glock *gl)
  {
  	struct gfs2_inode *ip = gl->gl_object;
  	struct address_space *metamapping = gfs2_glock2aspace(gl);
  	int error;
  
  	if (ip && !S_ISREG(ip->i_inode.i_mode))
  		ip = NULL;
  	if (ip) {
  		if (test_and_clear_bit(GIF_SW_PAGED, &ip->i_flags))
  			unmap_shared_mapping_range(ip->i_inode.i_mapping, 0, 0);
  		inode_dio_wait(&ip->i_inode);
  	}
  	if (!test_and_clear_bit(GLF_DIRTY, &gl->gl_flags))
  		return;
  
  	GLOCK_BUG_ON(gl, gl->gl_state != LM_ST_EXCLUSIVE);
  
  	gfs2_log_flush(gl->gl_name.ln_sbd, gl, NORMAL_FLUSH);
  	filemap_fdatawrite(metamapping);
  	if (ip) {
  		struct address_space *mapping = ip->i_inode.i_mapping;
  		filemap_fdatawrite(mapping);
  		error = filemap_fdatawait(mapping);
  		mapping_set_error(mapping, error);
  	}
  	error = filemap_fdatawait(metamapping);
  	mapping_set_error(metamapping, error);
  	gfs2_ail_empty_gl(gl);
  	/*
  	 * Writeback of the data mapping may cause the dirty flag to be set
  	 * so we have to clear it again here.
  	 */
  	smp_mb__before_atomic();
  	clear_bit(GLF_DIRTY, &gl->gl_flags);
  }
  
  /**
   * inode_go_inval - prepare a inode glock to be released
   * @gl: the glock
   * @flags:
   *
   * Normally we invalidate everything, but if we are moving into
   * LM_ST_DEFERRED from LM_ST_SHARED or LM_ST_EXCLUSIVE then we
   * can keep hold of the metadata, since it won't have changed.
   *
   */
  
  static void inode_go_inval(struct gfs2_glock *gl, int flags)
  {
  	struct gfs2_inode *ip = gl->gl_object;
  
  	gfs2_assert_withdraw(gl->gl_name.ln_sbd, !atomic_read(&gl->gl_ail_count));
  
  	if (flags & DIO_METADATA) {
  		struct address_space *mapping = gfs2_glock2aspace(gl);
  		truncate_inode_pages(mapping, 0);
  		if (ip) {
  			set_bit(GIF_INVALID, &ip->i_flags);
  			forget_all_cached_acls(&ip->i_inode);
  			gfs2_dir_hash_inval(ip);
  		}
  	}
  
  	if (ip == GFS2_I(gl->gl_name.ln_sbd->sd_rindex)) {
  		gfs2_log_flush(gl->gl_name.ln_sbd, NULL, NORMAL_FLUSH);
  		gl->gl_name.ln_sbd->sd_rindex_uptodate = 0;
  	}
  	if (ip && S_ISREG(ip->i_inode.i_mode))
  		truncate_inode_pages(ip->i_inode.i_mapping, 0);
  }
  
  /**
   * inode_go_demote_ok - Check to see if it's ok to unlock an inode glock
   * @gl: the glock
   *
   * Returns: 1 if it's ok
   */
  
  static int inode_go_demote_ok(const struct gfs2_glock *gl)
  {
  	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
  	struct gfs2_holder *gh;
  
  	if (sdp->sd_jindex == gl->gl_object || sdp->sd_rindex == gl->gl_object)
  		return 0;
  
  	if (!list_empty(&gl->gl_holders)) {
  		gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
  		if (gh->gh_list.next != &gl->gl_holders)
  			return 0;
  	}
  
  	return 1;
  }
  
  /**
   * gfs2_set_nlink - Set the inode's link count based on on-disk info
   * @inode: The inode in question
   * @nlink: The link count
   *
   * If the link count has hit zero, it must never be raised, whatever the
   * on-disk inode might say. When new struct inodes are created the link
   * count is set to 1, so that we can safely use this test even when reading
   * in on disk information for the first time.
   */
  
  static void gfs2_set_nlink(struct inode *inode, u32 nlink)
  {
  	/*
  	 * We will need to review setting the nlink count here in the
  	 * light of the forthcoming ro bind mount work. This is a reminder
  	 * to do that.
  	 */
  	if ((inode->i_nlink != nlink) && (inode->i_nlink != 0)) {
  		if (nlink == 0)
  			clear_nlink(inode);
  		else
  			set_nlink(inode, nlink);
  	}
  }
  
  static int gfs2_dinode_in(struct gfs2_inode *ip, const void *buf)
  {
  	const struct gfs2_dinode *str = buf;
  	struct timespec atime;
  	u16 height, depth;
  
  	if (unlikely(ip->i_no_addr != be64_to_cpu(str->di_num.no_addr)))
  		goto corrupt;
  	ip->i_no_formal_ino = be64_to_cpu(str->di_num.no_formal_ino);
  	ip->i_inode.i_mode = be32_to_cpu(str->di_mode);
  	ip->i_inode.i_rdev = 0;
  	switch (ip->i_inode.i_mode & S_IFMT) {
  	case S_IFBLK:
  	case S_IFCHR:
  		ip->i_inode.i_rdev = MKDEV(be32_to_cpu(str->di_major),
  					   be32_to_cpu(str->di_minor));
  		break;
  	};
  
  	i_uid_write(&ip->i_inode, be32_to_cpu(str->di_uid));
  	i_gid_write(&ip->i_inode, be32_to_cpu(str->di_gid));
  	gfs2_set_nlink(&ip->i_inode, be32_to_cpu(str->di_nlink));
  	i_size_write(&ip->i_inode, be64_to_cpu(str->di_size));
  	gfs2_set_inode_blocks(&ip->i_inode, be64_to_cpu(str->di_blocks));
  	atime.tv_sec = be64_to_cpu(str->di_atime);
  	atime.tv_nsec = be32_to_cpu(str->di_atime_nsec);
  	if (timespec_compare(&ip->i_inode.i_atime, &atime) < 0)
  		ip->i_inode.i_atime = atime;
  	ip->i_inode.i_mtime.tv_sec = be64_to_cpu(str->di_mtime);
  	ip->i_inode.i_mtime.tv_nsec = be32_to_cpu(str->di_mtime_nsec);
  	ip->i_inode.i_ctime.tv_sec = be64_to_cpu(str->di_ctime);
  	ip->i_inode.i_ctime.tv_nsec = be32_to_cpu(str->di_ctime_nsec);
  
  	ip->i_goal = be64_to_cpu(str->di_goal_meta);
  	ip->i_generation = be64_to_cpu(str->di_generation);
  
  	ip->i_diskflags = be32_to_cpu(str->di_flags);
  	ip->i_eattr = be64_to_cpu(str->di_eattr);
  	/* i_diskflags and i_eattr must be set before gfs2_set_inode_flags() */
  	gfs2_set_inode_flags(&ip->i_inode);
  	height = be16_to_cpu(str->di_height);
  	if (unlikely(height > GFS2_MAX_META_HEIGHT))
  		goto corrupt;
  	ip->i_height = (u8)height;
  
  	depth = be16_to_cpu(str->di_depth);
  	if (unlikely(depth > GFS2_DIR_MAX_DEPTH))
  		goto corrupt;
  	ip->i_depth = (u8)depth;
  	ip->i_entries = be32_to_cpu(str->di_entries);
  
  	if (S_ISREG(ip->i_inode.i_mode))
  		gfs2_set_aops(&ip->i_inode);
  
  	return 0;
  corrupt:
  	gfs2_consist_inode(ip);
  	return -EIO;
  }
  
  /**
   * gfs2_inode_refresh - Refresh the incore copy of the dinode
   * @ip: The GFS2 inode
   *
   * Returns: errno
   */
  
  int gfs2_inode_refresh(struct gfs2_inode *ip)
  {
  	struct buffer_head *dibh;
  	int error;
  
  	error = gfs2_meta_inode_buffer(ip, &dibh);
  	if (error)
  		return error;
  
  	error = gfs2_dinode_in(ip, dibh->b_data);
  	brelse(dibh);
  	clear_bit(GIF_INVALID, &ip->i_flags);
  
  	return error;
  }
  
  /**
   * inode_go_lock - operation done after an inode lock is locked by a process
   * @gl: the glock
   * @flags:
   *
   * Returns: errno
   */
  
  static int inode_go_lock(struct gfs2_holder *gh)
  {
  	struct gfs2_glock *gl = gh->gh_gl;
  	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
  	struct gfs2_inode *ip = gl->gl_object;
  	int error = 0;
  
  	if (!ip || (gh->gh_flags & GL_SKIP))
  		return 0;
  
  	if (test_bit(GIF_INVALID, &ip->i_flags)) {
  		error = gfs2_inode_refresh(ip);
  		if (error)
  			return error;
  	}
  
  	if (gh->gh_state != LM_ST_DEFERRED)
  		inode_dio_wait(&ip->i_inode);
  
  	if ((ip->i_diskflags & GFS2_DIF_TRUNC_IN_PROG) &&
  	    (gl->gl_state == LM_ST_EXCLUSIVE) &&
  	    (gh->gh_state == LM_ST_EXCLUSIVE)) {
  		spin_lock(&sdp->sd_trunc_lock);
  		if (list_empty(&ip->i_trunc_list))
  			list_add(&sdp->sd_trunc_list, &ip->i_trunc_list);
  		spin_unlock(&sdp->sd_trunc_lock);
  		wake_up(&sdp->sd_quota_wait);
  		return 1;
  	}
  
  	return error;
  }
  
  /**
   * inode_go_dump - print information about an inode
   * @seq: The iterator
   * @ip: the inode
   *
   */
  
  static void inode_go_dump(struct seq_file *seq, const struct gfs2_glock *gl)
  {
  	const struct gfs2_inode *ip = gl->gl_object;
  	if (ip == NULL)
  		return;
  	gfs2_print_dbg(seq, " I: n:%llu/%llu t:%u f:0x%02lx d:0x%08x s:%llu
  ",
  		  (unsigned long long)ip->i_no_formal_ino,
  		  (unsigned long long)ip->i_no_addr,
  		  IF2DT(ip->i_inode.i_mode), ip->i_flags,
  		  (unsigned int)ip->i_diskflags,
  		  (unsigned long long)i_size_read(&ip->i_inode));
  }
  
  /**
   * freeze_go_sync - promote/demote the freeze glock
   * @gl: the glock
   * @state: the requested state
   * @flags:
   *
   */
  
  static void freeze_go_sync(struct gfs2_glock *gl)
  {
  	int error = 0;
  	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
  
  	if (gl->gl_state == LM_ST_SHARED &&
  	    test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags)) {
  		atomic_set(&sdp->sd_freeze_state, SFS_STARTING_FREEZE);
  		error = freeze_super(sdp->sd_vfs);
  		if (error) {
  			printk(KERN_INFO "GFS2: couldn't freeze filesystem: %d
  ", error);
  			gfs2_assert_withdraw(sdp, 0);
  		}
  		queue_work(gfs2_freeze_wq, &sdp->sd_freeze_work);
  		gfs2_log_flush(sdp, NULL, FREEZE_FLUSH);
  	}
  }
  
  /**
   * freeze_go_xmote_bh - After promoting/demoting the freeze glock
   * @gl: the glock
   *
   */
  
  static int freeze_go_xmote_bh(struct gfs2_glock *gl, struct gfs2_holder *gh)
  {
  	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
  	struct gfs2_inode *ip = GFS2_I(sdp->sd_jdesc->jd_inode);
  	struct gfs2_glock *j_gl = ip->i_gl;
  	struct gfs2_log_header_host head;
  	int error;
  
  	if (test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags)) {
  		j_gl->gl_ops->go_inval(j_gl, DIO_METADATA);
  
  		error = gfs2_find_jhead(sdp->sd_jdesc, &head);
  		if (error)
  			gfs2_consist(sdp);
  		if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT))
  			gfs2_consist(sdp);
  
  		/*  Initialize some head of the log stuff  */
  		if (!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)) {
  			sdp->sd_log_sequence = head.lh_sequence + 1;
  			gfs2_log_pointers_init(sdp, head.lh_blkno);
  		}
  	}
  	return 0;
  }
  
  /**
   * trans_go_demote_ok
   * @gl: the glock
   *
   * Always returns 0
   */
  
  static int freeze_go_demote_ok(const struct gfs2_glock *gl)
  {
  	return 0;
  }
  
  /**
   * iopen_go_callback - schedule the dcache entry for the inode to be deleted
   * @gl: the glock
   *
   * gl_lockref.lock lock is held while calling this
   */
  static void iopen_go_callback(struct gfs2_glock *gl, bool remote)
  {
  	struct gfs2_inode *ip = (struct gfs2_inode *)gl->gl_object;
  	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
  
  	if (!remote || (sdp->sd_vfs->s_flags & MS_RDONLY))
  		return;
  
  	if (gl->gl_demote_state == LM_ST_UNLOCKED &&
  	    gl->gl_state == LM_ST_SHARED && ip) {
  		gl->gl_lockref.count++;
  		if (queue_work(gfs2_delete_workqueue, &gl->gl_delete) == 0)
  			gl->gl_lockref.count--;
  	}
  }
  
  const struct gfs2_glock_operations gfs2_meta_glops = {
  	.go_type = LM_TYPE_META,
  };
  
  const struct gfs2_glock_operations gfs2_inode_glops = {
  	.go_sync = inode_go_sync,
  	.go_inval = inode_go_inval,
  	.go_demote_ok = inode_go_demote_ok,
  	.go_lock = inode_go_lock,
  	.go_dump = inode_go_dump,
  	.go_type = LM_TYPE_INODE,
  	.go_flags = GLOF_ASPACE | GLOF_LRU,
  };
  
  const struct gfs2_glock_operations gfs2_rgrp_glops = {
  	.go_sync = rgrp_go_sync,
  	.go_inval = rgrp_go_inval,
  	.go_lock = gfs2_rgrp_go_lock,
  	.go_unlock = gfs2_rgrp_go_unlock,
  	.go_dump = gfs2_rgrp_dump,
  	.go_type = LM_TYPE_RGRP,
  	.go_flags = GLOF_LVB,
  };
  
  const struct gfs2_glock_operations gfs2_freeze_glops = {
  	.go_sync = freeze_go_sync,
  	.go_xmote_bh = freeze_go_xmote_bh,
  	.go_demote_ok = freeze_go_demote_ok,
  	.go_type = LM_TYPE_NONDISK,
  };
  
  const struct gfs2_glock_operations gfs2_iopen_glops = {
  	.go_type = LM_TYPE_IOPEN,
  	.go_callback = iopen_go_callback,
  	.go_flags = GLOF_LRU,
  };
  
  const struct gfs2_glock_operations gfs2_flock_glops = {
  	.go_type = LM_TYPE_FLOCK,
  	.go_flags = GLOF_LRU,
  };
  
  const struct gfs2_glock_operations gfs2_nondisk_glops = {
  	.go_type = LM_TYPE_NONDISK,
  };
  
  const struct gfs2_glock_operations gfs2_quota_glops = {
  	.go_type = LM_TYPE_QUOTA,
  	.go_flags = GLOF_LVB | GLOF_LRU,
  };
  
  const struct gfs2_glock_operations gfs2_journal_glops = {
  	.go_type = LM_TYPE_JOURNAL,
  };
  
  const struct gfs2_glock_operations *gfs2_glops_list[] = {
  	[LM_TYPE_META] = &gfs2_meta_glops,
  	[LM_TYPE_INODE] = &gfs2_inode_glops,
  	[LM_TYPE_RGRP] = &gfs2_rgrp_glops,
  	[LM_TYPE_IOPEN] = &gfs2_iopen_glops,
  	[LM_TYPE_FLOCK] = &gfs2_flock_glops,
  	[LM_TYPE_NONDISK] = &gfs2_nondisk_glops,
  	[LM_TYPE_QUOTA] = &gfs2_quota_glops,
  	[LM_TYPE_JOURNAL] = &gfs2_journal_glops,
  };