Ocfs2 devel - Aug 2015 - [patch 11/28] ocfs2: extend enough credits for freeing one truncate record while replaying truncate records

From: Xue jiufei <xuejiufei at huawei.com>
Subject: ocfs2: extend enough credits for freeing one truncate record while
replaying truncate records

Now function ocfs2_replay_truncate_records() first modifies tl_used, then
calls ocfs2_extend_trans() to extend transactions for gd and alloc inode
used for freeing clusters.  jbd2_journal_restart() may be called and it
may happen that tl_used in truncate log is decreased but the clusters are
not freed, which means these clusters are lost.  So we should avoid
extending transactions in these two operations.

Signed-off-by: joyce.xue <xuejiufei at huawei.com>
Cc: Mark Fasheh <mfasheh at suse.com>
Cc: Joel Becker <jlbec at evilplan.org>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
---

 fs/ocfs2/alloc.c |   19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff -puN
fs/ocfs2/alloc.c~extend-enough-credits-for-freeing-one-truncate-record-while-replaying-truncate-records
fs/ocfs2/alloc.c
---
a/fs/ocfs2/alloc.c~extend-enough-credits-for-freeing-one-truncate-record-while-replaying-truncate-records
+++ a/fs/ocfs2/alloc.c
@@ -5975,16 +5975,6 @@ static int ocfs2_replay_truncate_records
 
 		ocfs2_journal_dirty(handle, tl_bh);
 
-		/* TODO: Perhaps we can calculate the bulk of the
-		 * credits up front rather than extending like
-		 * this. */
-		status = ocfs2_extend_trans(handle,
-					    OCFS2_TRUNCATE_LOG_FLUSH_ONE_REC);
-		if (status < 0) {
-			mlog_errno(status);
-			goto bail;
-		}
-
 		rec = tl->tl_recs[i];
 		start_blk = ocfs2_clusters_to_blocks(data_alloc_inode->i_sb,
 						    le32_to_cpu(rec.t_start));
@@ -6005,6 +5995,13 @@ static int ocfs2_replay_truncate_records
 				goto bail;
 			}
 		}
+
+		status = ocfs2_extend_trans(handle,
+				OCFS2_TRUNCATE_LOG_FLUSH_ONE_REC);
+		if (status < 0) {
+			mlog_errno(status);
+			goto bail;
+		}
 		i--;
 	}
 
@@ -6063,7 +6060,7 @@ int __ocfs2_flush_truncate_log(struct oc
 		goto out_mutex;
 	}
 
-	handle = ocfs2_start_trans(osb, OCFS2_TRUNCATE_LOG_UPDATE);
+	handle = ocfs2_start_trans(osb, OCFS2_TRUNCATE_LOG_FLUSH_ONE_REC);
 	if (IS_ERR(handle)) {
 		status = PTR_ERR(handle);
 		mlog_errno(status);
_

On Wed, Aug 26, 2015 at 03:11:48PM -0700, Andrew Morton
wrote:
> From: Xue jiufei <xuejiufei at huawei.com>
> Subject: ocfs2: extend enough credits for freeing one truncate record while
replaying truncate records
> 
> Now function ocfs2_replay_truncate_records() first modifies tl_used, then
> calls ocfs2_extend_trans() to extend transactions for gd and alloc inode
> used for freeing clusters.  jbd2_journal_restart() may be called and it
> may happen that tl_used in truncate log is decreased but the clusters are
> not freed, which means these clusters are lost.  So we should avoid
> extending transactions in these two operations.
> 
> Signed-off-by: joyce.xue <xuejiufei at huawei.com>
> Cc: Mark Fasheh <mfasheh at suse.com>
> Cc: Joel Becker <jlbec at evilplan.org>
> Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
> ---
> 
>  fs/ocfs2/alloc.c |   19 ++++++++-----------
>  1 file changed, 8 insertions(+), 11 deletions(-)
> 
> diff -puN
fs/ocfs2/alloc.c~extend-enough-credits-for-freeing-one-truncate-record-while-replaying-truncate-records
fs/ocfs2/alloc.c
> ---
a/fs/ocfs2/alloc.c~extend-enough-credits-for-freeing-one-truncate-record-while-replaying-truncate-records
> +++ a/fs/ocfs2/alloc.c
<looks good>
> @@ -6063,7 +6060,7 @@ int __ocfs2_flush_truncate_log(struct oc
>  		goto out_mutex;
>  	}
>  
> -	handle = ocfs2_start_trans(osb, OCFS2_TRUNCATE_LOG_UPDATE);
> +	handle = ocfs2_start_trans(osb, OCFS2_TRUNCATE_LOG_FLUSH_ONE_REC);
>  	if (IS_ERR(handle)) {
>  		status = PTR_ERR(handle);
>  		mlog_errno(status);
Why is this particular change here?
	--Mark

--
Mark Fasheh