From: Sahitya Tummala <stummala@codeaurora.org>
To: zhengliang <zhengliang6@huawei.com>
Cc: jaegeuk@kernel.org, linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [PATCH v4] f2fs: fix to data block override node segment by mistake
Date: Mon, 4 Mar 2019 10:18:53 +0530 [thread overview]
Message-ID: <20190304044853.GB8377@codeaurora.org> (raw)
In-Reply-To: <46bb1ca2-e768-274b-6d98-3ff4323abd1f@huawei.com>
On Mon, Mar 04, 2019 at 09:32:25AM +0800, zhengliang wrote:
> v4: Rearrange the previous three versions.
>
> The following scenario could lead to data block override by mistake.
>
> TASK A | TASK kworker | TASK B | TASK C
> | | |
> open | | |
> write | | |
> close | | |
> | f2fs_write_data_pages | |
> | f2fs_write_cache_pages | |
> | f2fs_outplace_write_data | |
> | f2fs_allocate_data_block (get block in seg S, | |
> | S is full, and only | |
> | have this valid data | |
> | block) | |
> | allocate_segment | |
> | locate_dirty_segment (mark S as PRE) | |
In Task kworker context, if there is one valid data block allocated from S, then how can
S be marked as PRE? Shouldn't it be DIRTY? Please clarify.
> | f2fs_submit_page_write (submit but is not | |
> | written on dev) | |
> unlink | | |
> iput_final | | |
> f2fs_drop_inode | | |
> f2fs_truncate | | |
> (not evict) | | |
> | | write_checkpoint |
> | | flush merged bio but not wait file data writeback |
> | | set_prefree_as_free (mark S as FREE) |
> | | | update NODE/DATA
> | | | allocate_segment (select S)
> | writeback done | |
>
> So we need to guarantee io complete before truncate inode in f2fs_drop_inode.
>
> Reviewed-by: Chao Yu <yuchao0@huawei.com>
> Signed-off-by: Zheng Liang <zhengliang6@huawei.com>
> --------
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index c46a1d43..60f0599 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -915,6 +915,10 @@ static int f2fs_drop_inode(struct inode *inode)
> sb_start_intwrite(inode->i_sb);
> f2fs_i_size_write(inode, 0);
>
> + f2fs_submit_merged_write_cond(F2FS_I_SB(inode),
> + inode, NULL, 0, DATA);
> + truncate_inode_pages_final(inode->i_mapping);
> +
> if (F2FS_HAS_BLOCKS(inode))
> f2fs_truncate(inode);
>
>
>
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
--
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next prev parent reply other threads:[~2019-03-04 4:49 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-04 1:32 [PATCH v4] f2fs: fix to data block override node segment by mistake zhengliang
2019-03-04 4:48 ` Sahitya Tummala [this message]
2019-03-04 12:32 ` zhengliang
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