2018-01-10 02:43:40

by Daeho Jeong

Subject: [PATCH] f2fs: handle newly created page when revoking inmem pages

When committing inmem pages is successful, we revoke already committed
blocks in __revoke_inmem_pages() and finally replace the committed
ones with the old blocks using f2fs_replace_block(). However, if
the committed block was newly created one, the address of the old
block is NEW_ADDR and __f2fs_replace_block() cannot handle NEW_ADDR
as new_blkaddr properly and a kernel panic occurrs.

Signed-off-by: Daeho Jeong <[email protected]>
Tested-by: Shu Tan <[email protected]>
---
fs/f2fs/segment.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index c117e09..463f420 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -248,7 +248,11 @@ static int __revoke_inmem_pages(struct inode *inode,
goto next;
}
get_node_info(sbi, dn.nid, &ni);
- f2fs_replace_block(sbi, &dn, dn.data_blkaddr,
+ if (cur->old_addr == NEW_ADDR) {
+ invalidate_blocks(sbi, dn.data_blkaddr);
+ f2fs_update_data_blkaddr(&dn, NULL_ADDR);
+ } else
+ f2fs_replace_block(sbi, &dn, dn.data_blkaddr,
cur->old_addr, ni.version, true, true);
f2fs_put_dnode(&dn);
}
--
1.9.1

2018-01-10 06:43:39

by Chao Yu

Subject: Re: [PATCH] f2fs: handle newly created page when revoking inmem pages

On 2018/1/10 10:43, Daeho Jeong wrote:
> When committing inmem pages is successful, we revoke already committed
> blocks in __revoke_inmem_pages() and finally replace the committed
> ones with the old blocks using f2fs_replace_block(). However, if
> the committed block was newly created one, the address of the old
> block is NEW_ADDR and __f2fs_replace_block() cannot handle NEW_ADDR
> as new_blkaddr properly and a kernel panic occurrs.

Good catch!

>
> Signed-off-by: Daeho Jeong <[email protected]>
> Tested-by: Shu Tan <[email protected]>
> ---
> fs/f2fs/segment.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index c117e09..463f420 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -248,7 +248,11 @@ static int __revoke_inmem_pages(struct inode *inode,
> goto next;
> }
> get_node_info(sbi, dn.nid, &ni);
> - f2fs_replace_block(sbi, &dn, dn.data_blkaddr,
> + if (cur->old_addr == NEW_ADDR) {
> + invalidate_blocks(sbi, dn.data_blkaddr);
> + f2fs_update_data_blkaddr(&dn, NULL_ADDR);

Original intention here is to recover status to the timing before
committing atomic write. As at that timing blkaddr in dnode should be
cur->old_addr(NEW_ADDR), so we need to change to call:

f2fs_update_data_blkaddr(&dn, NEW_ADDR);

Otherwise, metadata will become inconsistent, because blkaddr value is
NULL_ADDR means that current block is not preallocated, but
total_valid_block_count has already been updated. Right?

Thanks,

> + } else
> + f2fs_replace_block(sbi, &dn, dn.data_blkaddr,
> cur->old_addr, ni.version, true, true);
> f2fs_put_dnode(&dn);
> }
>

2018-01-10 07:25:59

by Daeho Jeong

Subject: Re: [PATCH] f2fs: handle newly created page when revoking inmem pages

Hi Chao,

> Original intention here is to recover status to the timing before
> committing atomic write. As at that timing blkaddr in dnode should be
> cur->old_addr(NEW_ADDR), so we need to change to call:
 
> f2fs_update_data_blkaddr(&dn, NEW_ADDR);

Ok, I'll change NULL_ADDR to NEW_ADDR.

Thanks,
 
> Otherwise, metadata will become inconsistent, because blkaddr value is
> NULL_ADDR means that current block is not preallocated, but
> total_valid_block_count has already been updated. Right?
 
> Thanks,