From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Changwei Ge <ge.changwei@h3c.com>
Date: Wed, 31 Jan 2018 16:15:02 -0800
Subject: [PATCH] ocfs2: make metadata estimation accurate and clear
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Current code assume that ::w_unwritten_list always has only one item on.
This is not right and hard to get understood.  So improve how to count
unwritten item.

Link: http://lkml.kernel.org/r/1515479070-32653-1-git-send-email-ge.changwei@h3c.com
Signed-off-by: Changwei Ge <ge.changwei@h3c.com>
Reported-by: John Lightsey <john@nixnuts.net>
Tested-by: John Lightsey <john@nixnuts.net>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Changwei Ge <ge.changwei@h3c.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit 63de8bd9328bf2a778fc277503da163ae3defa3c)
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
---
 fs/ocfs2/aops.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index d1516327b787..256986aca8df 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -797,6 +797,7 @@ struct ocfs2_write_ctxt {
 	struct ocfs2_cached_dealloc_ctxt w_dealloc;
 
 	struct list_head		w_unwritten_list;
+	unsigned int			w_unwritten_count;
 };
 
 void ocfs2_unlock_and_free_pages(struct page **pages, int num_pages)
@@ -1386,6 +1387,7 @@ static int ocfs2_unwritten_check(struct inode *inode,
 	desc->c_clear_unwritten = 0;
 	list_add_tail(&new->ue_ip_node, &oi->ip_unwritten_list);
 	list_add_tail(&new->ue_node, &wc->w_unwritten_list);
+	wc->w_unwritten_count++;
 	new = NULL;
 unlock:
 	spin_unlock(&oi->ip_lock);
@@ -2256,7 +2258,7 @@ static int ocfs2_dio_wr_get_block(struct inode *inode, sector_t iblock,
 		ue->ue_phys = desc->c_phys;
 
 		list_splice_tail_init(&wc->w_unwritten_list, &dwc->dw_zero_list);
-		dwc->dw_zero_count++;
+		dwc->dw_zero_count += wc->w_unwritten_count;
 	}
 
 	ret = ocfs2_write_end_nolock(inode->i_mapping, pos, len, len, wc);
-- 
2.14.2

