On 2018/4/10 14:40, Jaegeuk Kim wrote:
> On 04/10, Chao Yu wrote:
>> On 2018/4/10 11:29, Jaegeuk Kim wrote:
>>> Change log from v2:
>>> - consider IO error case when dealing with metapage
>>> - memset by fill_node_footer
>>>
>>> Change log from v1:
>>> - don't memset for recovered page
>>>
>>> Related to https://lkml.org/lkml/2018/4/8/661
>>>
>>> Sometimes, we need to write meta data to new allocated block address,
>>> then we will allocate a zeroed page in inner inode's address space, and
>>> fill partial data in it, and leave other place with zero value which means
>>> some fields are initial status.
>>>
>>> There are two inner inodes (meta inode and node inode) setting __GFP_ZERO,
>>> I have just checked them, for both of them, we can avoid using __GFP_ZERO,
>>> and do initialization by ourselves to avoid unneeded/redundant zeroing
>>> from mm.
>>>
>>> Cc: <sta...@vger.kernel.org>
>>> Signed-off-by: Chao Yu <yuch...@huawei.com>
>>> Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org>
>>> ---
>>> fs/f2fs/checkpoint.c | 4 +++-
>>> fs/f2fs/inode.c | 4 ++--
>>> fs/f2fs/segment.c | 3 +++
>>> fs/f2fs/segment.h | 1 +
>>> 4 files changed, 9 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
>>> index bf779461df13..2e23b953d304 100644
>>> --- a/fs/f2fs/checkpoint.c
>>> +++ b/fs/f2fs/checkpoint.c
>>> @@ -100,8 +100,10 @@ static struct page *__get_meta_page(struct
>>> f2fs_sb_info *sbi, pgoff_t index,
>>> * readonly and make sure do not write checkpoint with non-uptodate
>>> * meta page.
>>> */
>>> - if (unlikely(!PageUptodate(page)))
>>> + if (unlikely(!PageUptodate(page))) {
>>> + memset(page_address(page), 0, PAGE_SIZE);
>>> f2fs_stop_checkpoint(sbi, false);
>>> + }
>>> out:
>>> return page;
>>> }
>>> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
>>> index 417c9dcd0269..87535bf63421 100644
>>> --- a/fs/f2fs/inode.c
>>> +++ b/fs/f2fs/inode.c
>>> @@ -320,10 +320,10 @@ struct inode *f2fs_iget(struct super_block *sb,
>>> unsigned long ino)
>>> make_now:
>>> if (ino == F2FS_NODE_INO(sbi)) {
>>> inode->i_mapping->a_ops = &f2fs_node_aops;
>>> - mapping_set_gfp_mask(inode->i_mapping, GFP_F2FS_ZERO);
>>> + mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
>>> } else if (ino == F2FS_META_INO(sbi)) {
>>> inode->i_mapping->a_ops = &f2fs_meta_aops;
>>> - mapping_set_gfp_mask(inode->i_mapping, GFP_F2FS_ZERO);
>>> + mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
>>> } else if (S_ISREG(inode->i_mode)) {
>>> inode->i_op = &f2fs_file_inode_operations;
>>> inode->i_fop = &f2fs_file_operations;
>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>> index a4b8e3e24ccb..1f5db557ab96 100644
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -2021,6 +2021,7 @@ static void write_current_sum_page(struct
>>> f2fs_sb_info *sbi,
>>> struct f2fs_summary_block *dst;
>>>
>>> dst = (struct f2fs_summary_block *)page_address(page);
>>> + memset(dst, 0, PAGE_SIZE);
>>
>> We will fill all summary page later, so we don't need initialize it?
>
> I'd like to reserve the uninitialzed space as zeros for future reference.
No problem, anyway, the patch is OK to me. :)
Thanks,
>
>>
>>>
>>> mutex_lock(&curseg->curseg_mutex);
>>>
>>> @@ -3117,6 +3118,7 @@ static void write_compacted_summaries(struct
>>> f2fs_sb_info *sbi, block_t blkaddr)
>>>
>>> page = grab_meta_page(sbi, blkaddr++);
>>> kaddr = (unsigned char *)page_address(page);
>>> + memset(kaddr, 0, PAGE_SIZE);
>>
>> I checked here, we will not use uninitialized space due to:
>>
>> read_compacted_summaries()
>> {
>> ...
>> if (offset + SUMMARY_SIZE <= PAGE_SIZE - SUM_FOOTER_SIZE)
>> continue;
>> ...
>> }
>>
>> Are we safe here?
>>
>>>
>>> /* Step 1: write nat cache */
>>> seg_i = CURSEG_I(sbi, CURSEG_HOT_DATA);
>>> @@ -3141,6 +3143,7 @@ static void write_compacted_summaries(struct
>>> f2fs_sb_info *sbi, block_t blkaddr)
>>> if (!page) {
>>> page = grab_meta_page(sbi, blkaddr++);
>>> kaddr = (unsigned char *)page_address(page);
>>> + memset(kaddr, 0, PAGE_SIZE);
>>
>> Ditto.
>>
>>> written_size = 0;
>>> }
>>> summary = (struct f2fs_summary *)(kaddr + written_size);
>>> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
>>> index 3325d0769723..492ad0c86fa9 100644
>>> --- a/fs/f2fs/segment.h
>>> +++ b/fs/f2fs/segment.h
>>> @@ -375,6 +375,7 @@ static inline void seg_info_to_sit_page(struct
>>> f2fs_sb_info *sbi,
>>> int i;
>>>
>>> raw_sit = (struct f2fs_sit_block *)page_address(page);
>>> + memset(raw_sit, 0, PAGE_SIZE);
>>
>> I suspect that root cause of panic is that we don't memset here?
>>
>> Thanks,
>>
>>> for (i = 0; i < end - start; i++) {
>>> rs = &raw_sit->entries[i];
>>> se = get_seg_entry(sbi, start + i);
>>>
>
> .
>
