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* [PATCH v3] f2fs: avoid dead loop in function find_fsync_dnodes
@ 2017-12-14  3:54 Yunlei He
  2017-12-14 11:03 ` Chao Yu
  0 siblings, 1 reply; 2+ messages in thread
From: Yunlei He @ 2017-12-14  3:54 UTC (permalink / raw)
  To: jaegeuk, yuchao0, linux-f2fs-devel; +Cc: ning.jia, heyunlei

Came across a dead loop in recovery like this:

......
[   24.680480s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597696
[   24.698394s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597697
[   24.724334s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
[   24.724334s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
[   24.724365s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
[   24.724365s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
[   24.724365s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
[   24.724395s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
[   24.724395s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
[   24.724395s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
[   24.724395s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
[   24.724426s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
......

Mount process will block in dead loop and fsck can do nothing with this
error, This patch abandon recovery if node chain is cyclical.

Signed-off-by: Yunlei He <heyunlei@huawei.com>
---
 fs/f2fs/data.c     |  5 +++++
 fs/f2fs/recovery.c | 23 +++++++++++++++--------
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 7aca6cc..2ac992f 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2146,6 +2146,9 @@ void f2fs_invalidate_page(struct page *page, unsigned int offset,
 		}
 	}
 
+	if (PageChecked(page))
+		ClearPageChecked(page);
+
 	/* This is atomic written page, keep Private */
 	if (IS_ATOMIC_WRITTEN_PAGE(page))
 		return drop_inmem_page(inode, page);
@@ -2292,6 +2295,8 @@ int f2fs_migrate_page(struct address_space *mapping,
 		SetPagePrivate(newpage);
 	set_page_private(newpage, page_private(page));
 
+	if (PageChecked(page))
+		SetPageChecked(page);
 	if (mode != MIGRATE_SYNC_NO_COPY)
 		migrate_page_copy(newpage, page);
 	else
diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index 7d63faf..905be02 100644
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -220,6 +220,14 @@ static void recover_inode(struct inode *inode, struct page *page)
 			ino_of_node(page), name);
 }
 
+static void destroy_fsync_dnodes(struct list_head *head)
+{
+	struct fsync_inode_entry *entry, *tmp;
+
+	list_for_each_entry_safe(entry, tmp, head, list)
+		del_fsync_inode(entry);
+}
+
 static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head,
 				bool check_only)
 {
@@ -239,7 +247,14 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head,
 			return 0;
 
 		page = get_tmp_page(sbi, blkaddr);
+		if (PageChecked(page)) {
+			f2fs_msg(sbi->sb, KERN_ERR, "Abandon dead loop node block list");
+			destroy_fsync_dnodes(head);
+			break;
+		}
 
+		/* No need ClearPageChecked for page cache truncated */
+		SetPageChecked(page);
 		if (!is_recoverable_dnode(page))
 			break;
 
@@ -288,14 +303,6 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head,
 	return err;
 }
 
-static void destroy_fsync_dnodes(struct list_head *head)
-{
-	struct fsync_inode_entry *entry, *tmp;
-
-	list_for_each_entry_safe(entry, tmp, head, list)
-		del_fsync_inode(entry);
-}
-
 static int check_index_in_prev_nodes(struct f2fs_sb_info *sbi,
 			block_t blkaddr, struct dnode_of_data *dn)
 {
-- 
1.9.1


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^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH v3] f2fs: avoid dead loop in function find_fsync_dnodes
  2017-12-14  3:54 [PATCH v3] f2fs: avoid dead loop in function find_fsync_dnodes Yunlei He
@ 2017-12-14 11:03 ` Chao Yu
  0 siblings, 0 replies; 2+ messages in thread
From: Chao Yu @ 2017-12-14 11:03 UTC (permalink / raw)
  To: Yunlei He, jaegeuk, linux-f2fs-devel; +Cc: ning.jia

On 2017/12/14 11:54, Yunlei He wrote:
> Came across a dead loop in recovery like this:
> 
> ......
> [   24.680480s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597696
> [   24.698394s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597697
> [   24.724334s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
> [   24.724334s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
> [   24.724365s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
> [   24.724365s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
> [   24.724365s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
> [   24.724395s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
> [   24.724395s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
> [   24.724395s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
> [   24.724395s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
> [   24.724426s][pid:320,cpu0,init]find_fsync_dnodes: blkaddr =13597698
> ......
> 
> Mount process will block in dead loop and fsck can do nothing with this
> error, This patch abandon recovery if node chain is cyclical.
> 
> Signed-off-by: Yunlei He <heyunlei@huawei.com>
> ---
>  fs/f2fs/data.c     |  5 +++++
>  fs/f2fs/recovery.c | 23 +++++++++++++++--------
>  2 files changed, 20 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 7aca6cc..2ac992f 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -2146,6 +2146,9 @@ void f2fs_invalidate_page(struct page *page, unsigned int offset,
>  		}
>  	}
>  
> +	if (PageChecked(page))
> +		ClearPageChecked(page);

IMO, we don't need to care about this flag like most other PG_* flags
during truncation.

> +
>  	/* This is atomic written page, keep Private */
>  	if (IS_ATOMIC_WRITTEN_PAGE(page))
>  		return drop_inmem_page(inode, page);
> @@ -2292,6 +2295,8 @@ int f2fs_migrate_page(struct address_space *mapping,
>  		SetPagePrivate(newpage);
>  	set_page_private(newpage, page_private(page));
>  
> +	if (PageChecked(page))
> +		SetPageChecked(page);

Actually, migrate_page_copy will do this job.

>  	if (mode != MIGRATE_SYNC_NO_COPY)
>  		migrate_page_copy(newpage, page);
>  	else
> diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
> index 7d63faf..905be02 100644
> --- a/fs/f2fs/recovery.c
> +++ b/fs/f2fs/recovery.c
> @@ -220,6 +220,14 @@ static void recover_inode(struct inode *inode, struct page *page)
>  			ino_of_node(page), name);
>  }
>  
> +static void destroy_fsync_dnodes(struct list_head *head)
> +{
> +	struct fsync_inode_entry *entry, *tmp;
> +
> +	list_for_each_entry_safe(entry, tmp, head, list)
> +		del_fsync_inode(entry);
> +}

How about moving this function behind del_fsync_inode?

> +
>  static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head,
>  				bool check_only)
>  {
> @@ -239,7 +247,14 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head,
>  			return 0;
>  
>  		page = get_tmp_page(sbi, blkaddr);
> +		if (PageChecked(page)) {
> +			f2fs_msg(sbi->sb, KERN_ERR, "Abandon dead loop node block list");

"Abandon looped node block list"

> +			destroy_fsync_dnodes(head);
> +			break;
> +		}
>  
> +		/* No need ClearPageChecked for page cache truncated */

/*
 * it's not needed to clear PG_checked flag in temp page since we
 * will truncate all those pages in the end of recovery.
 */

> +		SetPageChecked(page);

Will looks more neat to leave a blank line here.

Thanks,

>  		if (!is_recoverable_dnode(page))
>  			break;
>  
> @@ -288,14 +303,6 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head,
>  	return err;
>  }
>  
> -static void destroy_fsync_dnodes(struct list_head *head)
> -{
> -	struct fsync_inode_entry *entry, *tmp;
> -
> -	list_for_each_entry_safe(entry, tmp, head, list)
> -		del_fsync_inode(entry);
> -}
> -
>  static int check_index_in_prev_nodes(struct f2fs_sb_info *sbi,
>  			block_t blkaddr, struct dnode_of_data *dn)
>  {
> 


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^ permalink raw reply	[flat|nested] 2+ messages in thread

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2017-12-14  3:54 [PATCH v3] f2fs: avoid dead loop in function find_fsync_dnodes Yunlei He
2017-12-14 11:03 ` Chao Yu

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