fs/gfs2/recovery.c - third_party/kernel - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
  */

 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/completion.h>
 #include <linux/buffer_head.h>
 #include <linux/gfs2_ondisk.h>
 #include <linux/crc32.h>
 #include <linux/crc32c.h>
 #include <linux/ktime.h>

 #include "gfs2.h"
 #include "incore.h"
 #include "bmap.h"
 #include "glock.h"
 #include "glops.h"
 #include "log.h"
 #include "lops.h"
 #include "meta_io.h"
 #include "recovery.h"
 #include "super.h"
 #include "util.h"
 #include "dir.h"

 struct workqueue_struct *gfs_recovery_wq;

 int gfs2_replay_read_block(struct gfs2_jdesc *jd, unsigned int blk,
 			   struct buffer_head **bh)
 {
 	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
 	struct gfs2_glock *gl = ip->i_gl;
 	u64 dblock;
 	u32 extlen;
 	int error;

 	extlen = 32;
 	error = gfs2_get_extent(&ip->i_inode, blk, &dblock, &extlen);
 	if (error)
 		return error;
 	if (!dblock) {
 		gfs2_consist_inode(ip);
 		return -EIO;
 	}

 	*bh = gfs2_meta_ra(gl, dblock, extlen);

 	return error;
 }

 int gfs2_revoke_add(struct gfs2_jdesc *jd, u64 blkno, unsigned int where)
 {
 	struct list_head *head = &jd->jd_revoke_list;
 	struct gfs2_revoke_replay *rr;
 	int found = 0;

 	list_for_each_entry(rr, head, rr_list) {
 		if (rr->rr_blkno == blkno) {
 			found = 1;
 			break;
 		}
 	}

 	if (found) {
 		rr->rr_where = where;
 		return 0;
 	}

 	rr = kmalloc(sizeof(struct gfs2_revoke_replay), GFP_NOFS);
 	if (!rr)
 		return -ENOMEM;

 	rr->rr_blkno = blkno;
 	rr->rr_where = where;
 	list_add(&rr->rr_list, head);

 	return 1;
 }

 int gfs2_revoke_check(struct gfs2_jdesc *jd, u64 blkno, unsigned int where)
 {
 	struct gfs2_revoke_replay *rr;
 	int wrap, a, b, revoke;
 	int found = 0;

 	list_for_each_entry(rr, &jd->jd_revoke_list, rr_list) {
 		if (rr->rr_blkno == blkno) {
 			found = 1;
 			break;
 		}
 	}

 	if (!found)
 		return 0;

 	wrap = (rr->rr_where < jd->jd_replay_tail);
 	a = (jd->jd_replay_tail < where);
 	b = (where < rr->rr_where);
 	revoke = (wrap) ? (a || b) : (a && b);

 	return revoke;
 }

 void gfs2_revoke_clean(struct gfs2_jdesc *jd)
 {
 	struct list_head *head = &jd->jd_revoke_list;
 	struct gfs2_revoke_replay *rr;

 	while (!list_empty(head)) {
 		rr = list_first_entry(head, struct gfs2_revoke_replay, rr_list);
 		list_del(&rr->rr_list);
 		kfree(rr);
 	}
 }

 int __get_log_header(struct gfs2_sbd *sdp, const struct gfs2_log_header *lh,
 		     unsigned int blkno, struct gfs2_log_header_host *head)
 {
 	u32 hash, crc;

 	if (lh->lh_header.mh_magic != cpu_to_be32(GFS2_MAGIC) ||
 	    lh->lh_header.mh_type != cpu_to_be32(GFS2_METATYPE_LH) ||
 	    (blkno && be32_to_cpu(lh->lh_blkno) != blkno))
 		return 1;

 	hash = crc32(~0, lh, LH_V1_SIZE - 4);
 	hash = ~crc32_le_shift(hash, 4); /* assume lh_hash is zero */

 	if (be32_to_cpu(lh->lh_hash) != hash)
 		return 1;

 	crc = crc32c(~0, (void *)lh + LH_V1_SIZE + 4,
 		     sdp->sd_sb.sb_bsize - LH_V1_SIZE - 4);

 	if ((lh->lh_crc != 0 && be32_to_cpu(lh->lh_crc) != crc))
 		return 1;

 	head->lh_sequence = be64_to_cpu(lh->lh_sequence);
 	head->lh_flags = be32_to_cpu(lh->lh_flags);
 	head->lh_tail = be32_to_cpu(lh->lh_tail);
 	head->lh_blkno = be32_to_cpu(lh->lh_blkno);

 	head->lh_local_total = be64_to_cpu(lh->lh_local_total);
 	head->lh_local_free = be64_to_cpu(lh->lh_local_free);
 	head->lh_local_dinodes = be64_to_cpu(lh->lh_local_dinodes);

 	return 0;
 }
 /**
  * get_log_header - read the log header for a given segment
  * @jd: the journal
  * @blk: the block to look at
  * @head: the log header to return
  *
  * Read the log header for a given segement in a given journal.  Do a few
  * sanity checks on it.
  *
  * Returns: 0 on success,
  *          1 if the header was invalid or incomplete,
  *          errno on error
  */

 static int get_log_header(struct gfs2_jdesc *jd, unsigned int blk,
 			  struct gfs2_log_header_host *head)
 {
 	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
 	struct buffer_head *bh;
 	int error;

 	error = gfs2_replay_read_block(jd, blk, &bh);
 	if (error)
 		return error;

 	error = __get_log_header(sdp, (const struct gfs2_log_header *)bh->b_data,
 				 blk, head);
 	brelse(bh);

 	return error;
 }

 /**
  * foreach_descriptor - go through the active part of the log
  * @jd: the journal
  * @start: the first log header in the active region
  * @end: the last log header (don't process the contents of this entry))
  * @pass: iteration number (foreach_descriptor() is called in a for() loop)
  *
  * Call a given function once for every log descriptor in the active
  * portion of the log.
  *
  * Returns: errno
  */

 static int foreach_descriptor(struct gfs2_jdesc *jd, u32 start,
 			      unsigned int end, int pass)
 {
 	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
 	struct buffer_head *bh;
 	struct gfs2_log_descriptor *ld;
 	int error = 0;
 	u32 length;
 	__be64 *ptr;
 	unsigned int offset = sizeof(struct gfs2_log_descriptor);
 	offset += sizeof(__be64) - 1;
 	offset &= ~(sizeof(__be64) - 1);

 	while (start != end) {
 		error = gfs2_replay_read_block(jd, start, &bh);
 		if (error)
 			return error;
 		if (gfs2_meta_check(sdp, bh)) {
 			brelse(bh);
 			return -EIO;
 		}
 		ld = (struct gfs2_log_descriptor *)bh->b_data;
 		length = be32_to_cpu(ld->ld_length);

 		if (be32_to_cpu(ld->ld_header.mh_type) == GFS2_METATYPE_LH) {
 			struct gfs2_log_header_host lh;
 			error = get_log_header(jd, start, &lh);
 			if (!error) {
 				gfs2_replay_incr_blk(jd, &start);
 				brelse(bh);
 				continue;
 			}
 			if (error == 1) {
 				gfs2_consist_inode(GFS2_I(jd->jd_inode));
 				error = -EIO;
 			}
 			brelse(bh);
 			return error;
 		} else if (gfs2_metatype_check(sdp, bh, GFS2_METATYPE_LD)) {
 			brelse(bh);
 			return -EIO;
 		}
 		ptr = (__be64 *)(bh->b_data + offset);
 		error = lops_scan_elements(jd, start, ld, ptr, pass);
 		if (error) {
 			brelse(bh);
 			return error;
 		}

 		while (length--)
 			gfs2_replay_incr_blk(jd, &start);

 		brelse(bh);
 	}

 	return 0;
 }

 /**
  * clean_journal - mark a dirty journal as being clean
  * @jd: the journal
  * @head: the head journal to start from
  *
  * Returns: errno
  */

 static void clean_journal(struct gfs2_jdesc *jd,
 			  struct gfs2_log_header_host *head)
 {
 	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
 	u32 lblock = head->lh_blkno;

 	gfs2_replay_incr_blk(jd, &lblock);
 	gfs2_write_log_header(sdp, jd, head->lh_sequence + 1, 0, lblock,
 			      GFS2_LOG_HEAD_UNMOUNT | GFS2_LOG_HEAD_RECOVERY,
 			      REQ_PREFLUSH | REQ_FUA | REQ_META | REQ_SYNC);
 	if (jd->jd_jid == sdp->sd_lockstruct.ls_jid) {
 		sdp->sd_log_flush_head = lblock;
 		gfs2_log_incr_head(sdp);
 	}
 }


 static void gfs2_recovery_done(struct gfs2_sbd *sdp, unsigned int jid,
                                unsigned int message)
 {
 	char env_jid[20];
 	char env_status[20];
 	char *envp[] = { env_jid, env_status, NULL };
 	struct lm_lockstruct *ls = &sdp->sd_lockstruct;

         ls->ls_recover_jid_done = jid;
         ls->ls_recover_jid_status = message;
 	sprintf(env_jid, "JID=%u", jid);
 	sprintf(env_status, "RECOVERY=%s",
 		message == LM_RD_SUCCESS ? "Done" : "Failed");
         kobject_uevent_env(&sdp->sd_kobj, KOBJ_CHANGE, envp);

 	if (sdp->sd_lockstruct.ls_ops->lm_recovery_result)
 		sdp->sd_lockstruct.ls_ops->lm_recovery_result(sdp, jid, message);
 }

 /**
  * update_statfs_inode - Update the master statfs inode or zero out the local
  *			 statfs inode for a given journal.
  * @jd: The journal
  * @head: If NULL, @inode is the local statfs inode and we need to zero it out.
  *	  Otherwise, it @head contains the statfs change info that needs to be
  *	  synced to the master statfs inode (pointed to by @inode).
  * @inode: statfs inode to update.
  */
 static int update_statfs_inode(struct gfs2_jdesc *jd,
 			       struct gfs2_log_header_host *head,
 			       struct inode *inode)
 {
 	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
 	struct gfs2_inode *ip;
 	struct buffer_head *bh;
 	struct gfs2_statfs_change_host sc;
 	int error = 0;

 	BUG_ON(!inode);
 	ip = GFS2_I(inode);

 	error = gfs2_meta_inode_buffer(ip, &bh);
 	if (error)
 		goto out;

 	spin_lock(&sdp->sd_statfs_spin);

 	if (head) { /* Update the master statfs inode */
 		gfs2_statfs_change_in(&sc, bh->b_data + sizeof(struct gfs2_dinode));
 		sc.sc_total += head->lh_local_total;
 		sc.sc_free += head->lh_local_free;
 		sc.sc_dinodes += head->lh_local_dinodes;
 		gfs2_statfs_change_out(&sc, bh->b_data + sizeof(struct gfs2_dinode));

 		fs_info(sdp, "jid=%u: Updated master statfs Total:%lld, "
 			"Free:%lld, Dinodes:%lld after change "
 			"[%+lld,%+lld,%+lld]\n", jd->jd_jid, sc.sc_total,
 			sc.sc_free, sc.sc_dinodes, head->lh_local_total,
 			head->lh_local_free, head->lh_local_dinodes);
 	} else { /* Zero out the local statfs inode */
 		memset(bh->b_data + sizeof(struct gfs2_dinode), 0,
 		       sizeof(struct gfs2_statfs_change));
 		/* If it's our own journal, reset any in-memory changes too */
 		if (jd->jd_jid == sdp->sd_lockstruct.ls_jid) {
 			memset(&sdp->sd_statfs_local, 0,
 			       sizeof(struct gfs2_statfs_change_host));
 		}
 	}
 	spin_unlock(&sdp->sd_statfs_spin);

 	mark_buffer_dirty(bh);
 	brelse(bh);
 	gfs2_inode_metasync(ip->i_gl);

 out:
 	return error;
 }

 /**
  * recover_local_statfs - Update the master and local statfs changes for this
  *			  journal.
  *
  * Previously, statfs updates would be read in from the local statfs inode and
  * synced to the master statfs inode during recovery.
  *
  * We now use the statfs updates in the journal head to update the master statfs
  * inode instead of reading in from the local statfs inode. To preserve backward
  * compatibility with kernels that can't do this, we still need to keep the
  * local statfs inode up to date by writing changes to it. At some point in the
  * future, we can do away with the local statfs inodes altogether and keep the
  * statfs changes solely in the journal.
  *
  * @jd: the journal
  * @head: the journal head
  *
  * Returns: errno
  */
 static void recover_local_statfs(struct gfs2_jdesc *jd,
 				 struct gfs2_log_header_host *head)
 {
 	int error;
 	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);

 	if (!head->lh_local_total && !head->lh_local_free
 	    && !head->lh_local_dinodes) /* No change */
 		goto zero_local;

 	 /* First update the master statfs inode with the changes we
 	  * found in the journal. */
 	error = update_statfs_inode(jd, head, sdp->sd_statfs_inode);
 	if (error)
 		goto out;

 zero_local:
 	/* Zero out the local statfs inode so any changes in there
 	 * are not re-recovered. */
 	error = update_statfs_inode(jd, NULL,
 				    find_local_statfs_inode(sdp, jd->jd_jid));
 out:
 	return;
 }

 void gfs2_recover_func(struct work_struct *work)
 {
 	struct gfs2_jdesc *jd = container_of(work, struct gfs2_jdesc, jd_work);
 	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
 	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
 	struct gfs2_log_header_host head;
 	struct gfs2_holder j_gh, ji_gh, thaw_gh;
 	ktime_t t_start, t_jlck, t_jhd, t_tlck, t_rep;
 	int ro = 0;
 	unsigned int pass;
 	int error = 0;
 	int jlocked = 0;

 	if (gfs2_withdrawn(sdp)) {
 		fs_err(sdp, "jid=%u: Recovery not attempted due to withdraw.\n",
 		       jd->jd_jid);
 		goto fail;
 	}
 	t_start = ktime_get();
 	if (sdp->sd_args.ar_spectator)
 		goto fail;
 	if (jd->jd_jid != sdp->sd_lockstruct.ls_jid) {
 		fs_info(sdp, "jid=%u: Trying to acquire journal lock...\n",
 			jd->jd_jid);
 		jlocked = 1;
 		/* Acquire the journal lock so we can do recovery */

 		error = gfs2_glock_nq_num(sdp, jd->jd_jid, &gfs2_journal_glops,
 					  LM_ST_EXCLUSIVE,
 					  LM_FLAG_NOEXP | LM_FLAG_TRY | GL_NOCACHE,
 					  &j_gh);
 		switch (error) {
 		case 0:
 			break;

 		case GLR_TRYFAILED:
 			fs_info(sdp, "jid=%u: Busy\n", jd->jd_jid);
 			error = 0;
 			goto fail;

 		default:
 			goto fail;
 		}

 		error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED,
 					   LM_FLAG_NOEXP | GL_NOCACHE, &ji_gh);
 		if (error)
 			goto fail_gunlock_j;
 	} else {
 		fs_info(sdp, "jid=%u, already locked for use\n", jd->jd_jid);
 	}

 	t_jlck = ktime_get();
 	fs_info(sdp, "jid=%u: Looking at journal...\n", jd->jd_jid);

 	error = gfs2_jdesc_check(jd);
 	if (error)
 		goto fail_gunlock_ji;

 	error = gfs2_find_jhead(jd, &head, true);
 	if (error)
 		goto fail_gunlock_ji;
 	t_jhd = ktime_get();
 	fs_info(sdp, "jid=%u: Journal head lookup took %lldms\n", jd->jd_jid,
 		ktime_ms_delta(t_jhd, t_jlck));

 	if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
 		fs_info(sdp, "jid=%u: Acquiring the transaction lock...\n",
 			jd->jd_jid);

 		/* Acquire a shared hold on the freeze lock */

 		error = gfs2_freeze_lock(sdp, &thaw_gh, LM_FLAG_PRIORITY);
 		if (error)
 			goto fail_gunlock_ji;

 		if (test_bit(SDF_RORECOVERY, &sdp->sd_flags)) {
 			ro = 1;
 		} else if (test_bit(SDF_JOURNAL_CHECKED, &sdp->sd_flags)) {
 			if (!test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags))
 				ro = 1;
 		} else {
 			if (sb_rdonly(sdp->sd_vfs)) {
 				/* check if device itself is read-only */
 				ro = bdev_read_only(sdp->sd_vfs->s_bdev);
 				if (!ro) {
 					fs_info(sdp, "recovery required on "
 						"read-only filesystem.\n");
 					fs_info(sdp, "write access will be "
 						"enabled during recovery.\n");
 				}
 			}
 		}

 		if (ro) {
 			fs_warn(sdp, "jid=%u: Can't replay: read-only block "
 				"device\n", jd->jd_jid);
 			error = -EROFS;
 			goto fail_gunlock_thaw;
 		}

 		t_tlck = ktime_get();
 		fs_info(sdp, "jid=%u: Replaying journal...0x%x to 0x%x\n",
 			jd->jd_jid, head.lh_tail, head.lh_blkno);

 		/* We take the sd_log_flush_lock here primarily to prevent log
 		 * flushes and simultaneous journal replays from stomping on
 		 * each other wrt jd_log_bio. */
 		down_read(&sdp->sd_log_flush_lock);
 		for (pass = 0; pass < 2; pass++) {
 			lops_before_scan(jd, &head, pass);
 			error = foreach_descriptor(jd, head.lh_tail,
 						   head.lh_blkno, pass);
 			lops_after_scan(jd, error, pass);
 			if (error) {
 				up_read(&sdp->sd_log_flush_lock);
 				goto fail_gunlock_thaw;
 			}
 		}

 		recover_local_statfs(jd, &head);
 		clean_journal(jd, &head);
 		up_read(&sdp->sd_log_flush_lock);

 		gfs2_freeze_unlock(&thaw_gh);
 		t_rep = ktime_get();
 		fs_info(sdp, "jid=%u: Journal replayed in %lldms [jlck:%lldms, "
 			"jhead:%lldms, tlck:%lldms, replay:%lldms]\n",
 			jd->jd_jid, ktime_ms_delta(t_rep, t_start),
 			ktime_ms_delta(t_jlck, t_start),
 			ktime_ms_delta(t_jhd, t_jlck),
 			ktime_ms_delta(t_tlck, t_jhd),
 			ktime_ms_delta(t_rep, t_tlck));
 	}

 	gfs2_recovery_done(sdp, jd->jd_jid, LM_RD_SUCCESS);

 	if (jlocked) {
 		gfs2_glock_dq_uninit(&ji_gh);
 		gfs2_glock_dq_uninit(&j_gh);
 	}

 	fs_info(sdp, "jid=%u: Done\n", jd->jd_jid);
 	goto done;

 fail_gunlock_thaw:
 	gfs2_freeze_unlock(&thaw_gh);
 fail_gunlock_ji:
 	if (jlocked) {
 		gfs2_glock_dq_uninit(&ji_gh);
 fail_gunlock_j:
 		gfs2_glock_dq_uninit(&j_gh);
 	}

 	fs_info(sdp, "jid=%u: %s\n", jd->jd_jid, (error) ? "Failed" : "Done");
 fail:
 	jd->jd_recover_error = error;
 	gfs2_recovery_done(sdp, jd->jd_jid, LM_RD_GAVEUP);
 done:
 	clear_bit(JDF_RECOVERY, &jd->jd_flags);
 	smp_mb__after_atomic();
 	wake_up_bit(&jd->jd_flags, JDF_RECOVERY);
 }

 int gfs2_recover_journal(struct gfs2_jdesc *jd, bool wait)
 {
 	int rv;

 	if (test_and_set_bit(JDF_RECOVERY, &jd->jd_flags))
 		return -EBUSY;

 	/* we have JDF_RECOVERY, queue should always succeed */
 	rv = queue_work(gfs_recovery_wq, &jd->jd_work);
 	BUG_ON(!rv);

 	if (wait)
 		wait_on_bit(&jd->jd_flags, JDF_RECOVERY,
 			    TASK_UNINTERRUPTIBLE);

 	return wait ? jd->jd_recover_error : 0;
 }
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
	* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
	*/

	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/spinlock.h>
	#include <linux/completion.h>
	#include <linux/buffer_head.h>
	#include <linux/gfs2_ondisk.h>
	#include <linux/crc32.h>
	#include <linux/crc32c.h>
	#include <linux/ktime.h>

	#include "gfs2.h"
	#include "incore.h"
	#include "bmap.h"
	#include "glock.h"
	#include "glops.h"
	#include "log.h"
	#include "lops.h"
	#include "meta_io.h"
	#include "recovery.h"
	#include "super.h"
	#include "util.h"
	#include "dir.h"

	struct workqueue_struct *gfs_recovery_wq;

	int gfs2_replay_read_block(struct gfs2_jdesc *jd, unsigned int blk,
	struct buffer_head **bh)
	{
	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
	struct gfs2_glock *gl = ip->i_gl;
	u64 dblock;
	u32 extlen;
	int error;

	extlen = 32;
	error = gfs2_get_extent(&ip->i_inode, blk, &dblock, &extlen);
	if (error)
	return error;
	if (!dblock) {
	gfs2_consist_inode(ip);
	return -EIO;
	}

	*bh = gfs2_meta_ra(gl, dblock, extlen);

	return error;
	}

	int gfs2_revoke_add(struct gfs2_jdesc *jd, u64 blkno, unsigned int where)
	{
	struct list_head *head = &jd->jd_revoke_list;
	struct gfs2_revoke_replay *rr;
	int found = 0;

	list_for_each_entry(rr, head, rr_list) {
	if (rr->rr_blkno == blkno) {
	found = 1;
	break;
	}
	}

	if (found) {
	rr->rr_where = where;
	return 0;
	}

	rr = kmalloc(sizeof(struct gfs2_revoke_replay), GFP_NOFS);
	if (!rr)
	return -ENOMEM;

	rr->rr_blkno = blkno;
	rr->rr_where = where;
	list_add(&rr->rr_list, head);

	return 1;
	}

	int gfs2_revoke_check(struct gfs2_jdesc *jd, u64 blkno, unsigned int where)
	{
	struct gfs2_revoke_replay *rr;
	int wrap, a, b, revoke;
	int found = 0;

	list_for_each_entry(rr, &jd->jd_revoke_list, rr_list) {
	if (rr->rr_blkno == blkno) {
	found = 1;
	break;
	}
	}

	if (!found)
	return 0;

	wrap = (rr->rr_where < jd->jd_replay_tail);
	a = (jd->jd_replay_tail < where);
	b = (where < rr->rr_where);
	revoke = (wrap) ? (a \|\| b) : (a && b);

	return revoke;
	}

	void gfs2_revoke_clean(struct gfs2_jdesc *jd)
	{
	struct list_head *head = &jd->jd_revoke_list;
	struct gfs2_revoke_replay *rr;

	while (!list_empty(head)) {
	rr = list_first_entry(head, struct gfs2_revoke_replay, rr_list);
	list_del(&rr->rr_list);
	kfree(rr);
	}
	}

	int __get_log_header(struct gfs2_sbd sdp, const struct gfs2_log_header lh,
	unsigned int blkno, struct gfs2_log_header_host *head)
	{
	u32 hash, crc;

	if (lh->lh_header.mh_magic != cpu_to_be32(GFS2_MAGIC) \|\|
	lh->lh_header.mh_type != cpu_to_be32(GFS2_METATYPE_LH) \|\|
	(blkno && be32_to_cpu(lh->lh_blkno) != blkno))
	return 1;

	hash = crc32(~0, lh, LH_V1_SIZE - 4);
	hash = ~crc32_le_shift(hash, 4); /* assume lh_hash is zero */

	if (be32_to_cpu(lh->lh_hash) != hash)
	return 1;

	crc = crc32c(~0, (void *)lh + LH_V1_SIZE + 4,
	sdp->sd_sb.sb_bsize - LH_V1_SIZE - 4);

	if ((lh->lh_crc != 0 && be32_to_cpu(lh->lh_crc) != crc))
	return 1;

	head->lh_sequence = be64_to_cpu(lh->lh_sequence);
	head->lh_flags = be32_to_cpu(lh->lh_flags);
	head->lh_tail = be32_to_cpu(lh->lh_tail);
	head->lh_blkno = be32_to_cpu(lh->lh_blkno);

	head->lh_local_total = be64_to_cpu(lh->lh_local_total);
	head->lh_local_free = be64_to_cpu(lh->lh_local_free);
	head->lh_local_dinodes = be64_to_cpu(lh->lh_local_dinodes);

	return 0;
	}
	/**
	* get_log_header - read the log header for a given segment
	* @jd: the journal
	* @blk: the block to look at
	* @head: the log header to return
	*
	* Read the log header for a given segement in a given journal. Do a few
	* sanity checks on it.
	*
	* Returns: 0 on success,
	* 1 if the header was invalid or incomplete,
	* errno on error
	*/

	static int get_log_header(struct gfs2_jdesc *jd, unsigned int blk,
	struct gfs2_log_header_host *head)
	{
	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
	struct buffer_head *bh;
	int error;

	error = gfs2_replay_read_block(jd, blk, &bh);
	if (error)
	return error;

	error = __get_log_header(sdp, (const struct gfs2_log_header *)bh->b_data,
	blk, head);
	brelse(bh);

	return error;
	}

	/**
	* foreach_descriptor - go through the active part of the log
	* @jd: the journal
	* @start: the first log header in the active region
	* @end: the last log header (don't process the contents of this entry))
	* @pass: iteration number (foreach_descriptor() is called in a for() loop)
	*
	* Call a given function once for every log descriptor in the active
	* portion of the log.
	*
	* Returns: errno
	*/

	static int foreach_descriptor(struct gfs2_jdesc *jd, u32 start,
	unsigned int end, int pass)
	{
	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
	struct buffer_head *bh;
	struct gfs2_log_descriptor *ld;
	int error = 0;
	u32 length;
	__be64 *ptr;
	unsigned int offset = sizeof(struct gfs2_log_descriptor);
	offset += sizeof(__be64) - 1;
	offset &= ~(sizeof(__be64) - 1);

	while (start != end) {
	error = gfs2_replay_read_block(jd, start, &bh);
	if (error)
	return error;
	if (gfs2_meta_check(sdp, bh)) {
	brelse(bh);
	return -EIO;
	}
	ld = (struct gfs2_log_descriptor *)bh->b_data;
	length = be32_to_cpu(ld->ld_length);

	if (be32_to_cpu(ld->ld_header.mh_type) == GFS2_METATYPE_LH) {
	struct gfs2_log_header_host lh;
	error = get_log_header(jd, start, &lh);
	if (!error) {
	gfs2_replay_incr_blk(jd, &start);
	brelse(bh);
	continue;
	}
	if (error == 1) {
	gfs2_consist_inode(GFS2_I(jd->jd_inode));
	error = -EIO;
	}
	brelse(bh);
	return error;
	} else if (gfs2_metatype_check(sdp, bh, GFS2_METATYPE_LD)) {
	brelse(bh);
	return -EIO;
	}
	ptr = (__be64 *)(bh->b_data + offset);
	error = lops_scan_elements(jd, start, ld, ptr, pass);
	if (error) {
	brelse(bh);
	return error;
	}

	while (length--)
	gfs2_replay_incr_blk(jd, &start);

	brelse(bh);
	}

	return 0;
	}

	/**
	* clean_journal - mark a dirty journal as being clean
	* @jd: the journal
	* @head: the head journal to start from
	*
	* Returns: errno
	*/

	static void clean_journal(struct gfs2_jdesc *jd,
	struct gfs2_log_header_host *head)
	{
	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
	u32 lblock = head->lh_blkno;

	gfs2_replay_incr_blk(jd, &lblock);
	gfs2_write_log_header(sdp, jd, head->lh_sequence + 1, 0, lblock,
	GFS2_LOG_HEAD_UNMOUNT \| GFS2_LOG_HEAD_RECOVERY,
	REQ_PREFLUSH \| REQ_FUA \| REQ_META \| REQ_SYNC);
	if (jd->jd_jid == sdp->sd_lockstruct.ls_jid) {
	sdp->sd_log_flush_head = lblock;
	gfs2_log_incr_head(sdp);
	}
	}


	static void gfs2_recovery_done(struct gfs2_sbd *sdp, unsigned int jid,
	unsigned int message)
	{
	char env_jid[20];
	char env_status[20];
	char *envp[] = { env_jid, env_status, NULL };
	struct lm_lockstruct *ls = &sdp->sd_lockstruct;

	ls->ls_recover_jid_done = jid;
	ls->ls_recover_jid_status = message;
	sprintf(env_jid, "JID=%u", jid);
	sprintf(env_status, "RECOVERY=%s",
	message == LM_RD_SUCCESS ? "Done" : "Failed");
	kobject_uevent_env(&sdp->sd_kobj, KOBJ_CHANGE, envp);

	if (sdp->sd_lockstruct.ls_ops->lm_recovery_result)
	sdp->sd_lockstruct.ls_ops->lm_recovery_result(sdp, jid, message);
	}

	/**
	* update_statfs_inode - Update the master statfs inode or zero out the local
	* statfs inode for a given journal.
	* @jd: The journal
	* @head: If NULL, @inode is the local statfs inode and we need to zero it out.
	* Otherwise, it @head contains the statfs change info that needs to be
	* synced to the master statfs inode (pointed to by @inode).
	* @inode: statfs inode to update.
	*/
	static int update_statfs_inode(struct gfs2_jdesc *jd,
	struct gfs2_log_header_host *head,
	struct inode *inode)
	{
	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
	struct gfs2_inode *ip;
	struct buffer_head *bh;
	struct gfs2_statfs_change_host sc;
	int error = 0;

	BUG_ON(!inode);
	ip = GFS2_I(inode);

	error = gfs2_meta_inode_buffer(ip, &bh);
	if (error)
	goto out;

	spin_lock(&sdp->sd_statfs_spin);

	if (head) { /* Update the master statfs inode */
	gfs2_statfs_change_in(&sc, bh->b_data + sizeof(struct gfs2_dinode));
	sc.sc_total += head->lh_local_total;
	sc.sc_free += head->lh_local_free;
	sc.sc_dinodes += head->lh_local_dinodes;
	gfs2_statfs_change_out(&sc, bh->b_data + sizeof(struct gfs2_dinode));

	fs_info(sdp, "jid=%u: Updated master statfs Total:%lld, "
	"Free:%lld, Dinodes:%lld after change "
	"[%+lld,%+lld,%+lld]\n", jd->jd_jid, sc.sc_total,
	sc.sc_free, sc.sc_dinodes, head->lh_local_total,
	head->lh_local_free, head->lh_local_dinodes);
	} else { /* Zero out the local statfs inode */
	memset(bh->b_data + sizeof(struct gfs2_dinode), 0,
	sizeof(struct gfs2_statfs_change));
	/* If it's our own journal, reset any in-memory changes too */
	if (jd->jd_jid == sdp->sd_lockstruct.ls_jid) {
	memset(&sdp->sd_statfs_local, 0,
	sizeof(struct gfs2_statfs_change_host));
	}
	}
	spin_unlock(&sdp->sd_statfs_spin);

	mark_buffer_dirty(bh);
	brelse(bh);
	gfs2_inode_metasync(ip->i_gl);

	out:
	return error;
	}

	/**
	* recover_local_statfs - Update the master and local statfs changes for this
	* journal.
	*
	* Previously, statfs updates would be read in from the local statfs inode and
	* synced to the master statfs inode during recovery.
	*
	* We now use the statfs updates in the journal head to update the master statfs
	* inode instead of reading in from the local statfs inode. To preserve backward
	* compatibility with kernels that can't do this, we still need to keep the
	* local statfs inode up to date by writing changes to it. At some point in the
	* future, we can do away with the local statfs inodes altogether and keep the
	* statfs changes solely in the journal.
	*
	* @jd: the journal
	* @head: the journal head
	*
	* Returns: errno
	*/
	static void recover_local_statfs(struct gfs2_jdesc *jd,
	struct gfs2_log_header_host *head)
	{
	int error;
	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);

	if (!head->lh_local_total && !head->lh_local_free
	&& !head->lh_local_dinodes) /* No change */
	goto zero_local;

	/* First update the master statfs inode with the changes we
	* found in the journal. */
	error = update_statfs_inode(jd, head, sdp->sd_statfs_inode);
	if (error)
	goto out;

	zero_local:
	/* Zero out the local statfs inode so any changes in there
	* are not re-recovered. */
	error = update_statfs_inode(jd, NULL,
	find_local_statfs_inode(sdp, jd->jd_jid));
	out:
	return;
	}

	void gfs2_recover_func(struct work_struct *work)
	{
	struct gfs2_jdesc *jd = container_of(work, struct gfs2_jdesc, jd_work);
	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
	struct gfs2_log_header_host head;
	struct gfs2_holder j_gh, ji_gh, thaw_gh;
	ktime_t t_start, t_jlck, t_jhd, t_tlck, t_rep;
	int ro = 0;
	unsigned int pass;
	int error = 0;
	int jlocked = 0;

	if (gfs2_withdrawn(sdp)) {
	fs_err(sdp, "jid=%u: Recovery not attempted due to withdraw.\n",
	jd->jd_jid);
	goto fail;
	}
	t_start = ktime_get();
	if (sdp->sd_args.ar_spectator)
	goto fail;
	if (jd->jd_jid != sdp->sd_lockstruct.ls_jid) {
	fs_info(sdp, "jid=%u: Trying to acquire journal lock...\n",
	jd->jd_jid);
	jlocked = 1;
	/* Acquire the journal lock so we can do recovery */

	error = gfs2_glock_nq_num(sdp, jd->jd_jid, &gfs2_journal_glops,
	LM_ST_EXCLUSIVE,
	LM_FLAG_NOEXP \| LM_FLAG_TRY \| GL_NOCACHE,
	&j_gh);
	switch (error) {
	case 0:
	break;

	case GLR_TRYFAILED:
	fs_info(sdp, "jid=%u: Busy\n", jd->jd_jid);
	error = 0;
	goto fail;

	default:
	goto fail;
	}

	error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED,
	LM_FLAG_NOEXP \| GL_NOCACHE, &ji_gh);
	if (error)
	goto fail_gunlock_j;
	} else {
	fs_info(sdp, "jid=%u, already locked for use\n", jd->jd_jid);
	}

	t_jlck = ktime_get();
	fs_info(sdp, "jid=%u: Looking at journal...\n", jd->jd_jid);

	error = gfs2_jdesc_check(jd);
	if (error)
	goto fail_gunlock_ji;

	error = gfs2_find_jhead(jd, &head, true);
	if (error)
	goto fail_gunlock_ji;
	t_jhd = ktime_get();
	fs_info(sdp, "jid=%u: Journal head lookup took %lldms\n", jd->jd_jid,
	ktime_ms_delta(t_jhd, t_jlck));

	if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
	fs_info(sdp, "jid=%u: Acquiring the transaction lock...\n",
	jd->jd_jid);

	/* Acquire a shared hold on the freeze lock */

	error = gfs2_freeze_lock(sdp, &thaw_gh, LM_FLAG_PRIORITY);
	if (error)
	goto fail_gunlock_ji;

	if (test_bit(SDF_RORECOVERY, &sdp->sd_flags)) {
	ro = 1;
	} else if (test_bit(SDF_JOURNAL_CHECKED, &sdp->sd_flags)) {
	if (!test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags))
	ro = 1;
	} else {
	if (sb_rdonly(sdp->sd_vfs)) {
	/* check if device itself is read-only */
	ro = bdev_read_only(sdp->sd_vfs->s_bdev);
	if (!ro) {
	fs_info(sdp, "recovery required on "
	"read-only filesystem.\n");
	fs_info(sdp, "write access will be "
	"enabled during recovery.\n");
	}
	}
	}

	if (ro) {
	fs_warn(sdp, "jid=%u: Can't replay: read-only block "
	"device\n", jd->jd_jid);
	error = -EROFS;
	goto fail_gunlock_thaw;
	}

	t_tlck = ktime_get();
	fs_info(sdp, "jid=%u: Replaying journal...0x%x to 0x%x\n",
	jd->jd_jid, head.lh_tail, head.lh_blkno);

	/* We take the sd_log_flush_lock here primarily to prevent log
	* flushes and simultaneous journal replays from stomping on
	* each other wrt jd_log_bio. */
	down_read(&sdp->sd_log_flush_lock);
	for (pass = 0; pass < 2; pass++) {
	lops_before_scan(jd, &head, pass);
	error = foreach_descriptor(jd, head.lh_tail,
	head.lh_blkno, pass);
	lops_after_scan(jd, error, pass);
	if (error) {
	up_read(&sdp->sd_log_flush_lock);
	goto fail_gunlock_thaw;
	}
	}

	recover_local_statfs(jd, &head);
	clean_journal(jd, &head);
	up_read(&sdp->sd_log_flush_lock);

	gfs2_freeze_unlock(&thaw_gh);
	t_rep = ktime_get();
	fs_info(sdp, "jid=%u: Journal replayed in %lldms [jlck:%lldms, "
	"jhead:%lldms, tlck:%lldms, replay:%lldms]\n",
	jd->jd_jid, ktime_ms_delta(t_rep, t_start),
	ktime_ms_delta(t_jlck, t_start),
	ktime_ms_delta(t_jhd, t_jlck),
	ktime_ms_delta(t_tlck, t_jhd),
	ktime_ms_delta(t_rep, t_tlck));
	}

	gfs2_recovery_done(sdp, jd->jd_jid, LM_RD_SUCCESS);

	if (jlocked) {
	gfs2_glock_dq_uninit(&ji_gh);
	gfs2_glock_dq_uninit(&j_gh);
	}

	fs_info(sdp, "jid=%u: Done\n", jd->jd_jid);
	goto done;

	fail_gunlock_thaw:
	gfs2_freeze_unlock(&thaw_gh);
	fail_gunlock_ji:
	if (jlocked) {
	gfs2_glock_dq_uninit(&ji_gh);
	fail_gunlock_j:
	gfs2_glock_dq_uninit(&j_gh);
	}

	fs_info(sdp, "jid=%u: %s\n", jd->jd_jid, (error) ? "Failed" : "Done");
	fail:
	jd->jd_recover_error = error;
	gfs2_recovery_done(sdp, jd->jd_jid, LM_RD_GAVEUP);
	done:
	clear_bit(JDF_RECOVERY, &jd->jd_flags);
	smp_mb__after_atomic();
	wake_up_bit(&jd->jd_flags, JDF_RECOVERY);
	}

	int gfs2_recover_journal(struct gfs2_jdesc *jd, bool wait)
	{
	int rv;

	if (test_and_set_bit(JDF_RECOVERY, &jd->jd_flags))
	return -EBUSY;

	/* we have JDF_RECOVERY, queue should always succeed */
	rv = queue_work(gfs_recovery_wq, &jd->jd_work);
	BUG_ON(!rv);

	if (wait)
	wait_on_bit(&jd->jd_flags, JDF_RECOVERY,
	TASK_UNINTERRUPTIBLE);

	return wait ? jd->jd_recover_error : 0;
	}