// SPDX-License-Identifier: GPL-2.0-only

  /*
   * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.

   * Copyright (C) 2004-2008 Red Hat, Inc.  All rights reserved.

   */

  #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 <linux/security.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"

  #include "lops.h"

  struct workqueue_struct *gfs2_freeze_wq;

  extern struct workqueue_struct *gfs2_control_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(gl->gl_name.ln_sbd, "AIL error
  ");
  	gfs2_withdraw(gl->gl_name.ln_sbd);

  }

  /**

   * __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 int gfs2_ail_empty_gl(struct gfs2_glock *gl)

  {

  	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;

  	struct gfs2_trans tr;

  	int ret;

  
  	memset(&tr, 0, sizeof(tr));

  	INIT_LIST_HEAD(&tr.tr_buf);
  	INIT_LIST_HEAD(&tr.tr_databuf);

  	INIT_LIST_HEAD(&tr.tr_ail1_list);
  	INIT_LIST_HEAD(&tr.tr_ail2_list);

  	tr.tr_revokes = atomic_read(&gl->gl_ail_count);

  	if (!tr.tr_revokes) {
  		bool have_revokes;
  		bool log_in_flight;
  
  		/*
  		 * We have nothing on the ail, but there could be revokes on
  		 * the sdp revoke queue, in which case, we still want to flush
  		 * the log and wait for it to finish.
  		 *
  		 * If the sdp revoke list is empty too, we might still have an
  		 * io outstanding for writing revokes, so we should wait for
  		 * it before returning.
  		 *
  		 * If none of these conditions are true, our revokes are all
  		 * flushed and we can return.
  		 */
  		gfs2_log_lock(sdp);
  		have_revokes = !list_empty(&sdp->sd_log_revokes);
  		log_in_flight = atomic_read(&sdp->sd_log_in_flight);
  		gfs2_log_unlock(sdp);
  		if (have_revokes)
  			goto flush;
  		if (log_in_flight)
  			log_flush_wait(sdp);

  		return 0;

  	}

  	/* 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);

  	tr.tr_ip = _RET_IP_;

  	ret = gfs2_log_reserve(sdp, tr.tr_reserved);
  	if (ret < 0)
  		return ret;

  	WARN_ON_ONCE(current->journal_info);

  	current->journal_info = &tr;

  	__gfs2_ail_flush(gl, 0, tr.tr_revokes);

  
  	gfs2_trans_end(sdp);

  flush:

  	gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL |
  		       GFS2_LFC_AIL_EMPTY_GL);

  	return 0;

  }

  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, GFS2_LOG_HEAD_FLUSH_NORMAL |
  		       GFS2_LFC_AIL_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

   * return to caller to demote/unlock the glock until I/O is complete.

   */

  static int 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 = gfs2_glock2rgrp(gl);

  	int error;
  
  	if (!test_and_clear_bit(GLF_DIRTY, &gl->gl_flags))

  		return 0;

  	GLOCK_BUG_ON(gl, gl->gl_state != LM_ST_EXCLUSIVE);

  	gfs2_log_flush(sdp, gl, GFS2_LOG_HEAD_FLUSH_NORMAL |
  		       GFS2_LFC_RGRP_GO_SYNC);

  	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);

  	WARN_ON_ONCE(error);

  	mapping_set_error(mapping, error);

  	if (!error)
  		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);

  	return error;

  }
  
  /**

   * 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 = gfs2_glock2rgrp(gl);

  
  	if (rgd)
  		gfs2_rgrp_brelse(rgd);

  	WARN_ON_ONCE(!(flags & DIO_METADATA));

  	truncate_inode_pages_range(mapping, gl->gl_vm.start, gl->gl_vm.end);

  	if (rgd)

  		rgd->rd_flags &= ~GFS2_RDF_UPTODATE;

  }

  static struct gfs2_inode *gfs2_glock2inode(struct gfs2_glock *gl)
  {
  	struct gfs2_inode *ip;
  
  	spin_lock(&gl->gl_lockref.lock);
  	ip = gl->gl_object;
  	if (ip)
  		set_bit(GIF_GLOP_PENDING, &ip->i_flags);
  	spin_unlock(&gl->gl_lockref.lock);
  	return ip;
  }

  struct gfs2_rgrpd *gfs2_glock2rgrp(struct gfs2_glock *gl)
  {
  	struct gfs2_rgrpd *rgd;
  
  	spin_lock(&gl->gl_lockref.lock);
  	rgd = gl->gl_object;
  	spin_unlock(&gl->gl_lockref.lock);
  
  	return rgd;
  }

  static void gfs2_clear_glop_pending(struct gfs2_inode *ip)
  {
  	if (!ip)
  		return;
  
  	clear_bit_unlock(GIF_GLOP_PENDING, &ip->i_flags);
  	wake_up_bit(&ip->i_flags, GIF_GLOP_PENDING);
  }

  /**

   * inode_go_sync - Sync the dirty data and/or metadata for an inode glock
   * @gl: the glock protecting the inode
   *
   */

  static int inode_go_sync(struct gfs2_glock *gl)

  {

  	struct gfs2_inode *ip = gfs2_glock2inode(gl);
  	int isreg = ip && S_ISREG(ip->i_inode.i_mode);

  	struct address_space *metamapping = gfs2_glock2aspace(gl);

  	int error = 0, ret;

  	if (isreg) {

  		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))

  		goto out;

  	GLOCK_BUG_ON(gl, gl->gl_state != LM_ST_EXCLUSIVE);

  	gfs2_log_flush(gl->gl_name.ln_sbd, gl, GFS2_LOG_HEAD_FLUSH_NORMAL |
  		       GFS2_LFC_INODE_GO_SYNC);

  	filemap_fdatawrite(metamapping);

  	if (isreg) {

  		struct address_space *mapping = ip->i_inode.i_mapping;
  		filemap_fdatawrite(mapping);
  		error = filemap_fdatawait(mapping);
  		mapping_set_error(mapping, error);

  	}

  	ret = filemap_fdatawait(metamapping);
  	mapping_set_error(metamapping, ret);
  	if (!error)
  		error = ret;

  	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);

  
  out:
  	gfs2_clear_glop_pending(ip);

  	return error;

  }
  
  /**

   * 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 = gfs2_glock2inode(gl);

  	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);

  			security_inode_invalidate_secctx(&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,

  			       GFS2_LOG_HEAD_FLUSH_NORMAL |
  			       GFS2_LFC_INODE_GO_INVAL);

  		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);

  
  	gfs2_clear_glop_pending(ip);

  }
  
  /**
   * 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;

  	if (sdp->sd_jindex == gl->gl_object || sdp->sd_rindex == gl->gl_object)
  		return 0;

  	return 1;

  }

  static int gfs2_dinode_in(struct gfs2_inode *ip, const void *buf)
  {
  	const struct gfs2_dinode *str = buf;

  	struct timespec64 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));

  	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 (timespec64_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(&ip->i_trunc_list, &sdp->sd_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

   * @fs_id_buf: file system id (may be empty)

   *

   */

  static void inode_go_dump(struct seq_file *seq, struct gfs2_glock *gl,
  			  const char *fs_id_buf)

  {

  	struct gfs2_inode *ip = gl->gl_object;
  	struct inode *inode = &ip->i_inode;
  	unsigned long nrpages;

  	if (ip == NULL)

  		return;

  
  	xa_lock_irq(&inode->i_data.i_pages);
  	nrpages = inode->i_data.nrpages;
  	xa_unlock_irq(&inode->i_data.i_pages);

  	gfs2_print_dbg(seq, "%s I: n:%llu/%llu t:%u f:0x%02lx d:0x%08x s:%llu "
  		       "p:%lu
  ", fs_id_buf,

  		  (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(inode), nrpages);

  }
  
  /**

   * freeze_go_sync - promote/demote the freeze glock

   * @gl: the glock
   * @state: the requested state
   * @flags:
   *
   */

  static int freeze_go_sync(struct gfs2_glock *gl)

  {

  	int error = 0;

  	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;

  	if (gl->gl_req == LM_ST_EXCLUSIVE && !gfs2_withdrawn(sdp)) {

  		atomic_set(&sdp->sd_freeze_state, SFS_STARTING_FREEZE);
  		error = freeze_super(sdp->sd_vfs);
  		if (error) {

  			fs_info(sdp, "GFS2: couldn't freeze filesystem: %d
  ",
  				error);

  			if (gfs2_withdrawn(sdp)) {
  				atomic_set(&sdp->sd_freeze_state, SFS_UNFROZEN);

  				return 0;

  			}

  			gfs2_assert_withdraw(sdp, 0);
  		}
  		queue_work(gfs2_freeze_wq, &sdp->sd_freeze_work);

  		if (test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags))
  			gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_FREEZE |
  				       GFS2_LFC_FREEZE_GO_SYNC);
  		else /* read-only mounts */
  			atomic_set(&sdp->sd_freeze_state, SFS_FROZEN);

  	}

  	return 0;

  }
  
  /**

   * 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, false);

  		if (error)
  			gfs2_consist(sdp);
  		if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT))
  			gfs2_consist(sdp);
  
  		/*  Initialize some head of the log stuff  */

  		if (!gfs2_withdrawn(sdp)) {

  			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 = gl->gl_object;

  	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;

  	if (!remote || sb_rdonly(sdp->sd_vfs))

  		return;

  
  	if (gl->gl_demote_state == LM_ST_UNLOCKED &&

  	    gl->gl_state == LM_ST_SHARED && ip) {

  		gl->gl_lockref.count++;

  		if (!queue_delayed_work(gfs2_delete_workqueue,
  					&gl->gl_delete, 0))

  			gl->gl_lockref.count--;

  	}
  }

  static int iopen_go_demote_ok(const struct gfs2_glock *gl)
  {
         return !gfs2_delete_work_queued(gl);
  }

  /**
   * inode_go_free - wake up anyone waiting for dlm's unlock ast to free it
   * @gl: glock being freed
   *
   * For now, this is only used for the journal inode glock. In withdraw
   * situations, we need to wait for the glock to be freed so that we know
   * other nodes may proceed with recovery / journal replay.
   */
  static void inode_go_free(struct gfs2_glock *gl)
  {
  	/* Note that we cannot reference gl_object because it's already set
  	 * to NULL by this point in its lifecycle. */
  	if (!test_bit(GLF_FREEING, &gl->gl_flags))
  		return;
  	clear_bit_unlock(GLF_FREEING, &gl->gl_flags);
  	wake_up_bit(&gl->gl_flags, GLF_FREEING);
  }
  
  /**
   * nondisk_go_callback - used to signal when a node did a withdraw
   * @gl: the nondisk glock
   * @remote: true if this came from a different cluster node
   *
   */
  static void nondisk_go_callback(struct gfs2_glock *gl, bool remote)
  {
  	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
  
  	/* Ignore the callback unless it's from another node, and it's the
  	   live lock. */
  	if (!remote || gl->gl_name.ln_number != GFS2_LIVE_LOCK)
  		return;
  
  	/* First order of business is to cancel the demote request. We don't
  	 * really want to demote a nondisk glock. At best it's just to inform
  	 * us of another node's withdraw. We'll keep it in SH mode. */
  	clear_bit(GLF_DEMOTE, &gl->gl_flags);
  	clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags);
  
  	/* Ignore the unlock if we're withdrawn, unmounting, or in recovery. */
  	if (test_bit(SDF_NORECOVERY, &sdp->sd_flags) ||
  	    test_bit(SDF_WITHDRAWN, &sdp->sd_flags) ||
  	    test_bit(SDF_REMOTE_WITHDRAW, &sdp->sd_flags))
  		return;
  
  	/* We only care when a node wants us to unlock, because that means
  	 * they want a journal recovered. */
  	if (gl->gl_demote_state != LM_ST_UNLOCKED)
  		return;
  
  	if (sdp->sd_args.ar_spectator) {
  		fs_warn(sdp, "Spectator node cannot recover journals.
  ");
  		return;
  	}
  
  	fs_warn(sdp, "Some node has withdrawn; checking for recovery.
  ");
  	set_bit(SDF_REMOTE_WITHDRAW, &sdp->sd_flags);
  	/*
  	 * We can't call remote_withdraw directly here or gfs2_recover_journal
  	 * because this is called from the glock unlock function and the
  	 * remote_withdraw needs to enqueue and dequeue the same "live" glock
  	 * we were called from. So we queue it to the control work queue in
  	 * lock_dlm.
  	 */
  	queue_delayed_work(gfs2_control_wq, &sdp->sd_control_work, 0);
  }

  const struct gfs2_glock_operations gfs2_meta_glops = {

  	.go_type = LM_TYPE_META,

  	.go_flags = GLOF_NONDISK,

  };

  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 | GLOF_LVB,

  	.go_free = inode_go_free,

  };

  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_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,

  	.go_flags = GLOF_NONDISK,

  };

  const struct gfs2_glock_operations gfs2_iopen_glops = {

  	.go_type = LM_TYPE_IOPEN,

  	.go_callback = iopen_go_callback,

  	.go_demote_ok = iopen_go_demote_ok,

  	.go_flags = GLOF_LRU | GLOF_NONDISK,

  };

  const struct gfs2_glock_operations gfs2_flock_glops = {

  	.go_type = LM_TYPE_FLOCK,

  	.go_flags = GLOF_LRU | GLOF_NONDISK,

  };

  const struct gfs2_glock_operations gfs2_nondisk_glops = {

  	.go_type = LM_TYPE_NONDISK,

  	.go_flags = GLOF_NONDISK,

  	.go_callback = nondisk_go_callback,

  };

  const struct gfs2_glock_operations gfs2_quota_glops = {

  	.go_type = LM_TYPE_QUOTA,

  	.go_flags = GLOF_LVB | GLOF_LRU | GLOF_NONDISK,

  };

  const struct gfs2_glock_operations gfs2_journal_glops = {

  	.go_type = LM_TYPE_JOURNAL,

  	.go_flags = GLOF_NONDISK,

  };

  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,
  };