Commit a31b4ec5 authored by Bob Peterson's avatar Bob Peterson Committed by Andreas Gruenbacher
Browse files

Revert "gfs2: eliminate tr_num_revoke_rm" 



This reverts commit e955537e.

Before patch e955537e, tr_num_revoke tracked the number of revokes
added to the transaction, and tr_num_revoke_rm tracked how many
revokes were removed. But since revokes are queued off the sdp
(superblock) pointer, some transactions could remove more revokes
than they added. (e.g. revokes added by a different process).
Commit e955537e eliminated transaction variable tr_num_revoke_rm,
but in order to do so, it changed the accounting to always use
tr_num_revoke for its math. Since you can remove more revokes than
you add, tr_num_revoke could now become a negative value.
This negative value broke the assert in function gfs2_trans_end:

	if (gfs2_assert_withdraw(sdp, (nbuf <=3D tr->tr_blocks) &&
			       (tr->tr_num_revoke <=3D tr->tr_revokes)))

One way to fix this is to simply remove the tr_num_revoke clause
from the assert and allow the value to become negative. Andreas
didn't like that idea, so instead, we decided to revert e955537e.

Signed-off-by: default avatarBob Peterson <rpeterso@redhat.com>
Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
parent c04f2e0d

fs/gfs2/incore.h

+1 −0
Original line number Diff line number Diff line
@@ -503,6 +503,7 @@ struct gfs2_trans { 
	unsigned int tr_num_buf_rm;

	unsigned int tr_num_databuf_rm;

	unsigned int tr_num_revoke;

	unsigned int tr_num_revoke_rm;



	struct list_head tr_list;

	struct list_head tr_databuf;

fs/gfs2/log.c

+2 −1
Original line number Diff line number Diff line
@@ -895,6 +895,7 @@ static void gfs2_merge_trans(struct gfs2_trans *old, struct gfs2_trans *new) 
	old->tr_num_buf_rm	+= new->tr_num_buf_rm;

	old->tr_num_databuf_rm	+= new->tr_num_databuf_rm;

	old->tr_num_revoke	+= new->tr_num_revoke;

	old->tr_num_revoke_rm	+= new->tr_num_revoke_rm;



	list_splice_tail_init(&new->tr_databuf, &old->tr_databuf);

	list_splice_tail_init(&new->tr_buf, &old->tr_buf);
@@ -916,7 +917,7 @@ static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr) 
		set_bit(TR_ATTACHED, &tr->tr_flags);

	}



	sdp->sd_log_committed_revoke += tr->tr_num_revoke;

	sdp->sd_log_committed_revoke += tr->tr_num_revoke - tr->tr_num_revoke_rm;

	reserved = calc_reserved(sdp);

	maxres = sdp->sd_log_blks_reserved + tr->tr_reserved;

	gfs2_assert_withdraw(sdp, maxres >= reserved);

fs/gfs2/trans.c

+3 −3
Original line number Diff line number Diff line
@@ -76,10 +76,10 @@ static void gfs2_print_trans(struct gfs2_sbd *sdp, const struct gfs2_trans *tr) 
	fs_warn(sdp, "blocks=%u revokes=%u reserved=%u touched=%u\n",

		tr->tr_blocks, tr->tr_revokes, tr->tr_reserved,

		test_bit(TR_TOUCHED, &tr->tr_flags));

	fs_warn(sdp, "Buf %u/%u Databuf %u/%u Revoke %u\n",

	fs_warn(sdp, "Buf %u/%u Databuf %u/%u Revoke %u/%u\n",

		tr->tr_num_buf_new, tr->tr_num_buf_rm,

		tr->tr_num_databuf_new, tr->tr_num_databuf_rm,

		tr->tr_num_revoke);

		tr->tr_num_revoke, tr->tr_num_revoke_rm);

}



void gfs2_trans_end(struct gfs2_sbd *sdp)
@@ -264,7 +264,7 @@ void gfs2_trans_remove_revoke(struct gfs2_sbd *sdp, u64 blkno, unsigned int len) 
			if (bd->bd_gl)

				gfs2_glock_remove_revoke(bd->bd_gl);

			kmem_cache_free(gfs2_bufdata_cachep, bd);

			tr->tr_num_revoke--;

			tr->tr_num_revoke_rm++;

			if (--n == 0)

				break;

		}

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