linux-kernel - [PATCH AUTOSEL 4.18 039/131] f2fs: Keep alloc_valid_block

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Message-ID: <20180902064601.183036-39-alexander.levin@microsoft.com>
Date:   Sun, 2 Sep 2018 13:03:49 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Daniel Rosenberg <drosen@...gle.com>,
        Jaegeuk Kim <jaegeuk@...nel.org>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL 4.18 039/131] f2fs: Keep alloc_valid_block_count in
 sync

From: Daniel Rosenberg <drosen@...gle.com>

[ Upstream commit 36b877af7992893b6d1ddbe96971cab5ab9e50eb ]

If we attempt to request more blocks than we have room for, we try to
instead request as much as we can, however, alloc_valid_block_count
is not decremented to match the new value, allowing it to drift higher
until the next checkpoint. This always decrements it when the requested
amount cannot be fulfilled.

Signed-off-by: Daniel Rosenberg <drosen@...gle.com>
Reviewed-by: Chao Yu <yuchao0@...wei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 fs/f2fs/f2fs.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 34af21f46f2c..03c07721da49 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1680,18 +1680,20 @@ static inline int inc_valid_block_count(struct f2fs_sb_info *sbi,
 		sbi->total_valid_block_count -= diff;
 		if (!*count) {
 			spin_unlock(&sbi->stat_lock);
-			percpu_counter_sub(&sbi->alloc_valid_block_count, diff);
 			goto enospc;
 		}
 	}
 	spin_unlock(&sbi->stat_lock);
 
-	if (unlikely(release))
+	if (unlikely(release)) {
+		percpu_counter_sub(&sbi->alloc_valid_block_count, release);
 		dquot_release_reservation_block(inode, release);
+	}
 	f2fs_i_blocks_write(inode, *count, true, true);
 	return 0;
 
 enospc:
+	percpu_counter_sub(&sbi->alloc_valid_block_count, release);
 	dquot_release_reservation_block(inode, release);
 	return -ENOSPC;
 }
-- 
2.17.1