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From: Daniel Rosenberg <drosen@google.com>
To: Jaegeuk Kim <jaegeuk@kernel.org>, Chao Yu <yuchao0@huawei.com>,
	Jonathan Corbet <corbet@lwn.net>,
	linux-f2fs-devel@lists.sourceforge.net
Cc: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, kernel-team@android.com,
	Daniel Rosenberg <drosen@google.com>
Subject: [PATCH v3 3/4] f2fs: Fix accounting for unusable blocks
Date: Wed, 29 May 2019 17:49:05 -0700	[thread overview]
Message-ID: <20190530004906.261170-4-drosen@google.com> (raw)
In-Reply-To: <20190530004906.261170-1-drosen@google.com>

Fixes possible underflows when dealing with unusable blocks.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
---
 fs/f2fs/f2fs.h | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 9b3d9977cd1ef..a39cc4ffeb4b1 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1769,8 +1769,12 @@ static inline int inc_valid_block_count(struct f2fs_sb_info *sbi,
 
 	if (!__allow_reserved_blocks(sbi, inode, true))
 		avail_user_block_count -= F2FS_OPTION(sbi).root_reserved_blocks;
-	if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED)))
-		avail_user_block_count -= sbi->unusable_block_count;
+	if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
+		if (avail_user_block_count > sbi->unusable_block_count)
+			avail_user_block_count = 0;
+		else
+			avail_user_block_count -= sbi->unusable_block_count;
+	}
 	if (unlikely(sbi->total_valid_block_count > avail_user_block_count)) {
 		diff = sbi->total_valid_block_count - avail_user_block_count;
 		if (diff > *count)
@@ -1970,7 +1974,7 @@ static inline int inc_valid_node_count(struct f2fs_sb_info *sbi,
 					struct inode *inode, bool is_inode)
 {
 	block_t	valid_block_count;
-	unsigned int valid_node_count;
+	unsigned int valid_node_count, user_block_count;
 	int err;
 
 	if (is_inode) {
@@ -1997,10 +2001,11 @@ static inline int inc_valid_node_count(struct f2fs_sb_info *sbi,
 
 	if (!__allow_reserved_blocks(sbi, inode, false))
 		valid_block_count += F2FS_OPTION(sbi).root_reserved_blocks;
+	user_block_count = sbi->user_block_count;
 	if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED)))
-		valid_block_count += sbi->unusable_block_count;
+		user_block_count -= sbi->unusable_block_count;
 
-	if (unlikely(valid_block_count > sbi->user_block_count)) {
+	if (unlikely(valid_block_count > user_block_count)) {
 		spin_unlock(&sbi->stat_lock);
 		goto enospc;
 	}
-- 
2.22.0.rc1.257.g3120a18244-goog


  parent reply	other threads:[~2019-05-30  0:53 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-30  0:49 [PATCH v3 0/4] F2FS Checkpointing without GC, related fixes Daniel Rosenberg
2019-05-30  0:49 ` [PATCH v3 1/4] f2fs: Lower threshold for disable_cp_again Daniel Rosenberg
2019-06-03 10:33   ` Chao Yu
2019-05-30  0:49 ` [PATCH v3 2/4] f2fs: Fix root reserved on remount Daniel Rosenberg
2019-06-03 10:34   ` Chao Yu
2019-05-30  0:49 ` Daniel Rosenberg [this message]
2019-06-03 10:39   ` [PATCH v3 3/4] f2fs: Fix accounting for unusable blocks Chao Yu
2019-06-03 20:26     ` Jaegeuk Kim
2019-06-04  1:46       ` Chao Yu
2019-05-30  0:49 ` [PATCH v3 4/4] f2fs: Add option to limit required GC for checkpoint=disable Daniel Rosenberg
2019-06-03 15:15   ` [f2fs-dev] " Chao Yu

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