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SubjectRe: [PATCH] f2fs: fix to avoid accessing uninitialized field of inode page in is_alive()
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On 2019-9-7 7:48, Jaegeuk Kim wrote:
> On 09/06, Chao Yu wrote:
>> If inode is newly created, inode page may not synchronize with inode cache,
>> so fields like .i_inline or .i_extra_isize could be wrong, in below call
>> path, we may access such wrong fields, result in failing to migrate valid
>> target block.
>
> If data is valid, how can we get new inode page?

is_alive()
{
...
node_page = f2fs_get_node_page(sbi, nid); <--- inode page

source_blkaddr = datablock_addr(NULL, node_page, ofs_in_node);
...
}

datablock_addr()
{
...
base = offset_in_addr(&raw_node->i); <--- the base could be wrong here due to
accessing uninitialized .i_inline of raw_node->i.
...
}

Thanks,

>
>>
>> - gc_data_segment
>> - is_alive
>> - datablock_addr
>> - offset_in_addr
>>
>> Fixes: 7a2af766af15 ("f2fs: enhance on-disk inode structure scalability")
>> Signed-off-by: Chao Yu <yuchao0@huawei.com>
>> ---
>> fs/f2fs/dir.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
>> index 765f13354d3f..b1840852967e 100644
>> --- a/fs/f2fs/dir.c
>> +++ b/fs/f2fs/dir.c
>> @@ -479,6 +479,9 @@ struct page *f2fs_init_inode_metadata(struct inode *inode, struct inode *dir,
>> if (IS_ERR(page))
>> return page;
>>
>> + /* synchronize inode page's data from inode cache */
>> + f2fs_update_inode(inode, page);
>> +
>> if (S_ISDIR(inode->i_mode)) {
>> /* in order to handle error case */
>> get_page(page);
>> --
>> 2.18.0.rc1

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