gfs2: Replace sd_freeze_state with SDF_FROZEN flag

Replace sd_freeze_state with a new SDF_FROZEN flag.

There no longer is a need for indicating that a freeze is in progress
(SDF_STARTING_FREEZE); we are now protecting the critical sections with
the sd_freeze_mutex.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Author: Andreas Gruenbacher

fs/gfs2/incore.h

@@ -608,12 +608,7 @@ enum {
 					 withdrawing */
 	SDF_DEACTIVATING	= 15,
 	SDF_EVICTING		= 16,
-};
-
-enum gfs2_freeze_state {
-	SFS_UNFROZEN		= 0,
-	SFS_STARTING_FREEZE	= 1,
-	SFS_FROZEN		= 2,
+	SDF_FROZEN		= 17,
 };
 
 #define GFS2_FSNAME_LEN		256
@@ -841,7 +836,6 @@ struct gfs2_sbd {
 
 	/* For quiescing the filesystem */
 	struct gfs2_holder sd_freeze_gh;
-	atomic_t sd_freeze_state;
 	struct mutex sd_freeze_mutex;
 
 	char sd_fsname[GFS2_FSNAME_LEN + 3 * sizeof(int) + 2];

fs/gfs2/log.c

@@ -914,9 +914,8 @@ void gfs2_write_log_header(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd,
 static void log_write_header(struct gfs2_sbd *sdp, u32 flags)
 {
 	blk_opf_t op_flags = REQ_PREFLUSH | REQ_FUA | REQ_META | REQ_SYNC;
-	enum gfs2_freeze_state state = atomic_read(&sdp->sd_freeze_state);
 
-	gfs2_assert_withdraw(sdp, (state != SFS_FROZEN));
+	gfs2_assert_withdraw(sdp, !test_bit(SDF_FROZEN, &sdp->sd_flags));
 
 	if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags)) {
 		gfs2_ordered_wait(sdp);
@@ -1036,7 +1035,7 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags)
 {
 	struct gfs2_trans *tr = NULL;
 	unsigned int reserved_blocks = 0, used_blocks = 0;
-	enum gfs2_freeze_state state = atomic_read(&sdp->sd_freeze_state);
+	bool frozen = test_bit(SDF_FROZEN, &sdp->sd_flags);
 	unsigned int first_log_head;
 	unsigned int reserved_revokes = 0;
 
@@ -1067,7 +1066,7 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags)
 		if (tr) {
 			sdp->sd_log_tr = NULL;
 			tr->tr_first = first_log_head;
-			if (unlikely (state == SFS_FROZEN)) {
+			if (unlikely(frozen)) {
 				if (gfs2_assert_withdraw_delayed(sdp,
 				       !tr->tr_num_buf_new && !tr->tr_num_databuf_new))
 					goto out_withdraw;
@@ -1092,7 +1091,7 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags)
 	if (flags & GFS2_LOG_HEAD_FLUSH_SHUTDOWN)
 		clear_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
 
-	if (unlikely(state == SFS_FROZEN))
+	if (unlikely(frozen))
 		if (gfs2_assert_withdraw_delayed(sdp, !reserved_revokes))
 			goto out_withdraw;
 

fs/gfs2/ops_fstype.c

@@ -135,7 +135,6 @@ static struct gfs2_sbd *init_sbd(struct super_block *sb)
 	init_rwsem(&sdp->sd_log_flush_lock);
 	atomic_set(&sdp->sd_log_in_flight, 0);
 	init_waitqueue_head(&sdp->sd_log_flush_wait);
-	atomic_set(&sdp->sd_freeze_state, SFS_UNFROZEN);
 	mutex_init(&sdp->sd_freeze_mutex);
 
 	return sdp;

fs/gfs2/recovery.c

@@ -467,7 +467,7 @@ void gfs2_recover_func(struct work_struct *work)
 	if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
 		mutex_lock(&sdp->sd_freeze_mutex);
 
-		if (atomic_read(&sdp->sd_freeze_state) != SFS_UNFROZEN) {
+		if (test_bit(SDF_FROZEN, &sdp->sd_flags)) {
 			mutex_unlock(&sdp->sd_freeze_mutex);
 			fs_warn(sdp, "jid=%u: Can't replay: filesystem "
 				"is frozen\n", jd->jd_jid);

fs/gfs2/super.c

@@ -689,26 +689,19 @@ static int gfs2_freeze_locally(struct gfs2_sbd *sdp)
 	struct super_block *sb = sdp->sd_vfs;
 	int error;
 
-	atomic_set(&sdp->sd_freeze_state, SFS_STARTING_FREEZE);
-
 	error = freeze_super(sb);
 	if (error)
-		goto fail;
+		return error;
 
 	if (test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags)) {
 		gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_FREEZE |
 			       GFS2_LFC_FREEZE_GO_SYNC);
 		if (gfs2_withdrawn(sdp)) {
 			thaw_super(sb);
-			error = -EIO;
-			goto fail;
+			return -EIO;
 		}
 	}
 	return 0;
-
-fail:
-	atomic_set(&sdp->sd_freeze_state, SFS_UNFROZEN);
-	return error;
 }
 
 static int gfs2_do_thaw(struct gfs2_sbd *sdp)
@@ -737,21 +730,21 @@ void gfs2_freeze_func(struct work_struct *work)
 
 	mutex_lock(&sdp->sd_freeze_mutex);
 	error = -EBUSY;
-	if (atomic_read(&sdp->sd_freeze_state) != SFS_UNFROZEN)
+	if (test_bit(SDF_FROZEN, &sdp->sd_flags))
 		goto freeze_failed;
 
 	error = gfs2_freeze_locally(sdp);
 	if (error)
 		goto freeze_failed;
 
 	gfs2_freeze_unlock(&sdp->sd_freeze_gh);
-	atomic_set(&sdp->sd_freeze_state, SFS_FROZEN);
+	set_bit(SDF_FROZEN, &sdp->sd_flags);
 
 	error = gfs2_do_thaw(sdp);
 	if (error)
 		goto out;
 
-	atomic_set(&sdp->sd_freeze_state, SFS_UNFROZEN);
+	clear_bit(SDF_FROZEN, &sdp->sd_flags);
 	goto out;
 
 freeze_failed:
@@ -776,7 +769,7 @@ static int gfs2_freeze_super(struct super_block *sb)
 	if (!mutex_trylock(&sdp->sd_freeze_mutex))
 		return -EBUSY;
 	error = -EBUSY;
-	if (atomic_read(&sdp->sd_freeze_state) != SFS_UNFROZEN)
+	if (test_bit(SDF_FROZEN, &sdp->sd_flags))
 		goto out;
 
 	for (;;) {
@@ -811,7 +804,7 @@ static int gfs2_freeze_super(struct super_block *sb)
 out:
 	if (!error) {
 		set_bit(SDF_FREEZE_INITIATOR, &sdp->sd_flags);
-		atomic_set(&sdp->sd_freeze_state, SFS_FROZEN);
+		set_bit(SDF_FROZEN, &sdp->sd_flags);
 	}
 	mutex_unlock(&sdp->sd_freeze_mutex);
 	return error;
@@ -840,7 +833,7 @@ static int gfs2_thaw_super(struct super_block *sb)
 
 	if (!error) {
 		clear_bit(SDF_FREEZE_INITIATOR, &sdp->sd_flags);
-		atomic_set(&sdp->sd_freeze_state, SFS_UNFROZEN);
+		clear_bit(SDF_FROZEN, &sdp->sd_flags);
 	}
 out:
 	mutex_unlock(&sdp->sd_freeze_mutex);

fs/gfs2/sys.c

@@ -82,6 +82,7 @@ static ssize_t status_show(struct gfs2_sbd *sdp, char *buf)
 		     "RO Recovery:              %d\n"
 		     "Skip DLM Unlock:          %d\n"
 		     "Force AIL Flush:          %d\n"
+		     "FS Freeze Initiator:      %d\n"
 		     "FS Frozen:                %d\n"
 		     "Withdrawing:              %d\n"
 		     "Withdraw In Prog:         %d\n"
@@ -112,6 +113,7 @@ static ssize_t status_show(struct gfs2_sbd *sdp, char *buf)
 		     test_bit(SDF_SKIP_DLM_UNLOCK, &f),
 		     test_bit(SDF_FORCE_AIL_FLUSH, &f),
 		     test_bit(SDF_FREEZE_INITIATOR, &f),
+		     test_bit(SDF_FROZEN, &f),
 		     test_bit(SDF_WITHDRAWING, &f),
 		     test_bit(SDF_WITHDRAW_IN_PROG, &f),
 		     test_bit(SDF_REMOTE_WITHDRAW, &f),

fs/gfs2/trans.c

@@ -233,7 +233,6 @@ void gfs2_trans_add_meta(struct gfs2_glock *gl, struct buffer_head *bh)
 	struct gfs2_bufdata *bd;
 	struct gfs2_meta_header *mh;
 	struct gfs2_trans *tr = current->journal_info;
-	enum gfs2_freeze_state state = atomic_read(&sdp->sd_freeze_state);
 
 	lock_buffer(bh);
 	if (buffer_pinned(bh)) {
@@ -267,7 +266,7 @@ void gfs2_trans_add_meta(struct gfs2_glock *gl, struct buffer_head *bh)
 		       (unsigned long long)bd->bd_bh->b_blocknr);
 		BUG();
 	}
-	if (unlikely(state == SFS_FROZEN)) {
+	if (unlikely(test_bit(SDF_FROZEN, &sdp->sd_flags))) {
 		fs_info(sdp, "GFS2:adding buf while frozen\n");
 		gfs2_assert_withdraw(sdp, 0);
 	}