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Date: Tue, 8 Jun 2021 07:08:50 +0800
From: Chao Yu <chao@...nel.org>
To: Jaegeuk Kim <jaegeuk@...nel.org>
Cc: Chao Yu <yuchao0@...wei.com>,
linux-f2fs-devel@...ts.sourceforge.net,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] f2fs: swap: remove dead codes
On 2021/6/8 0:47, Jaegeuk Kim wrote:
> On 06/07, Chao Yu wrote:
>> On 2021/6/5 7:51, Jaegeuk Kim wrote:
>>> On 06/04, Chao Yu wrote:
>>>> On 2021/5/27 10:12, Chao Yu wrote:
>>>>> On 2021/5/27 9:40, Jaegeuk Kim wrote:
>>>>>> On 05/26, Chao Yu wrote:
>>>>>>> On 2021/5/26 21:30, Jaegeuk Kim wrote:
>>>>>>>> On 05/26, Chao Yu wrote:
>>>>>>>>> After commit af4b6b8edf6a ("f2fs: introduce check_swap_activate_fast()"),
>>>>>>>>> we will never run into original logic of check_swap_activate() before
>>>>>>>>> f2fs supports non 4k-sized page, so let's delete those dead codes.
>>>>>>>>
>>>>>>>> Why not keeping this for large page support in future maybe?
>>>>>>>
>>>>>>> Well, if so, at that time, it would be better to refactor
>>>>>>> check_swap_activate_fast() implementation based on f2fs_map_block() rather
>>>>>>> than refactoring check_swap_activate() implementation based on low efficient
>>>>>>> bmap()?
>>>>>>
>>>>>> Let's first check whether we support large page. Have you quickly tested it?
>>>>>> If we support it now and current flow is just inefficient, I'd say keeping but
>>>>>> refactoring it later.
>>>>>
>>>>> Let me check this, but I guess it missed to handle large page in lots of flows,
>>>>> not sure where we may panic at... :(
>>>>
>>>> I've checked f2fs behavior on 64kb page size in arm64 vm,
>>>> - 'ls -ls' will cause f2fs printing "invalid namelen(0), ino:%u, run fsck
>>>> to fix." each time.
>>>> - after touch a file and umount, fsck reports that image is corrupted.
>>>>
>>>> F2FS uses PAGE_SIZE and F2FS_BLKSIZE directly in a lot of places, I doubt
>>>> most of places may not consider large page size condition.
>>>>
>>>> So, thoughts? I guess we have to admit we do not support 64KB page right
>>>> now... :P
>>>
>>> Yeah, we need to block the large page support unfortunately. :(
>>
>> Could you please queue this series in dev-test?
>>
>> Thanks,
>>
>>>
>>>>
>>>> Thanks,
>>>>
>>>>>
>>>>> Thanks,
>>>>>
>>>>>>
>>>>>>>
>>>>>>> Thanks,
>>>>>>>
>>>>>>>>
>>>>>>>>>
>>>>>>>>> Signed-off-by: Chao Yu <yuchao0@...wei.com>
>>>>>>>>> ---
>>>>>>>>> fs/f2fs/data.c | 171 +------------------------------------------------
>>>>>>>>> 1 file changed, 3 insertions(+), 168 deletions(-)
>>>>>>>>>
>>>>>>>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>>>>>>>> index 3058c7e28b11..9c23fde93b76 100644
>>>>>>>>> --- a/fs/f2fs/data.c
>>>>>>>>> +++ b/fs/f2fs/data.c
>>>>>>>>> @@ -3830,67 +3830,7 @@ int f2fs_migrate_page(struct address_space *mapping,
>>>>>>>>> #endif
>>>>>>>>> #ifdef CONFIG_SWAP
>>>>>>>>> -static int f2fs_is_file_aligned(struct inode *inode)
>>>>>>>>> -{
>>>>>>>>> - struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>>>>>>>>> - block_t main_blkaddr = SM_I(sbi)->main_blkaddr;
>>>>>>>>> - block_t cur_lblock;
>>>>>>>>> - block_t last_lblock;
>>>>>>>>> - block_t pblock;
>>>>>>>>> - unsigned long nr_pblocks;
>>>>>>>>> - unsigned int blocks_per_sec = BLKS_PER_SEC(sbi);
>>>>>>>>> - unsigned int not_aligned = 0;
>>>>>>>>> - int ret = 0;
>>>>>>>>> -
>>>>>>>>> - cur_lblock = 0;
>>>>>>>>> - last_lblock = bytes_to_blks(inode, i_size_read(inode));
>>>>>>>>> -
>>>>>>>>> - while (cur_lblock < last_lblock) {
>>>>>>>>> - struct f2fs_map_blocks map;
>>>>>>>>> -
>>>>>>>>> - memset(&map, 0, sizeof(map));
>>>>>>>>> - map.m_lblk = cur_lblock;
>>>>>>>>> - map.m_len = last_lblock - cur_lblock;
>>>>>>>>> - map.m_next_pgofs = NULL;
>>>>>>>>> - map.m_next_extent = NULL;
>>>>>>>>> - map.m_seg_type = NO_CHECK_TYPE;
>>>>>>>>> - map.m_may_create = false;
>>>>>>>>> -
>>>>>>>>> - ret = f2fs_map_blocks(inode, &map, 0, F2FS_GET_BLOCK_FIEMAP);
>>>>>>>>> - if (ret)
>>>>>>>>> - goto out;
>>>>>>>>> -
>>>>>>>>> - /* hole */
>>>>>>>>> - if (!(map.m_flags & F2FS_MAP_FLAGS)) {
>>>>>>>>> - f2fs_err(sbi, "Swapfile has holes\n");
>>>>>>>>> - ret = -ENOENT;
>>>>>>>>> - goto out;
>>>>>>>>> - }
>>>>>>>>> -
>>>>>>>>> - pblock = map.m_pblk;
>>>>>>>>> - nr_pblocks = map.m_len;
>>>>>>>>> -
>>>>>>>>> - if ((pblock - main_blkaddr) & (blocks_per_sec - 1) ||
>>>>>>>>> - nr_pblocks & (blocks_per_sec - 1)) {
>>>>>>>>> - if (f2fs_is_pinned_file(inode)) {
>>>>>>>>> - f2fs_err(sbi, "Swapfile does not align to section");
>>>>>>>>> - ret = -EINVAL;
>>>>>>>>> - goto out;
>>>>>>>>> - }
>>>>>>>>> - not_aligned++;
>>>>>>>>> - }
>>>>>>>>> -
>>>>>>>>> - cur_lblock += nr_pblocks;
>>>>>>>>> - }
>>>>>>>>> - if (not_aligned)
>>>>>>>>> - f2fs_warn(sbi, "Swapfile (%u) is not align to section: \n"
>>>>>>>>> - "\t1) creat(), 2) ioctl(F2FS_IOC_SET_PIN_FILE), 3) fallocate()",
>>>>>>>>> - not_aligned);
>>>>>>>>> -out:
>>>>>>>>> - return ret;
>>>>>>>>> -}
>>>>>>>>> -
>>>>>>>>> -static int check_swap_activate_fast(struct swap_info_struct *sis,
>>>>>>>>> +static int check_swap_activate(struct swap_info_struct *sis,
>>>>>>>>> struct file *swap_file, sector_t *span)
>>>>>>>>> {
>>>>>>>>> struct address_space *mapping = swap_file->f_mapping;
>>>>>>>>> @@ -3907,6 +3847,8 @@ static int check_swap_activate_fast(struct swap_info_struct *sis,
>>>>>>>>> unsigned int not_aligned = 0;
>>>>>>>>> int ret = 0;
>>>>>>>>> + f2fs_bug_on(sbi, PAGE_SIZE != F2FS_BLKSIZE);
>
> Let me remove this, since we have this actually.
Looks fine to me.
Thanks,
>
> in init_f2fs_fs(),
>
> if (PAGE_SIZE != F2FS_BLKSIZE) {
> printk("F2FS not supported on PAGE_SIZE(%lu) != %d\n",
> PAGE_SIZE, F2FS_BLKSIZE);
> return -EINVAL;
> }
>
>
>
>>>>>>>>> +
>>>>>>>>> /*
>>>>>>>>> * Map all the blocks into the extent list. This code doesn't try
>>>>>>>>> * to be very smart.
>>>>>>>>> @@ -3986,113 +3928,6 @@ static int check_swap_activate_fast(struct swap_info_struct *sis,
>>>>>>>>> return ret;
>>>>>>>>> }
>>>>>>>>> -/* Copied from generic_swapfile_activate() to check any holes */
>>>>>>>>> -static int check_swap_activate(struct swap_info_struct *sis,
>>>>>>>>> - struct file *swap_file, sector_t *span)
>>>>>>>>> -{
>>>>>>>>> - struct address_space *mapping = swap_file->f_mapping;
>>>>>>>>> - struct inode *inode = mapping->host;
>>>>>>>>> - struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>>>>>>>>> - unsigned blocks_per_page;
>>>>>>>>> - unsigned long page_no;
>>>>>>>>> - sector_t probe_block;
>>>>>>>>> - sector_t last_block;
>>>>>>>>> - sector_t lowest_block = -1;
>>>>>>>>> - sector_t highest_block = 0;
>>>>>>>>> - int nr_extents = 0;
>>>>>>>>> - int ret = 0;
>>>>>>>>> -
>>>>>>>>> - if (PAGE_SIZE == F2FS_BLKSIZE)
>>>>>>>>> - return check_swap_activate_fast(sis, swap_file, span);
>>>>>>>>> -
>>>>>>>>> - ret = f2fs_is_file_aligned(inode);
>>>>>>>>> - if (ret)
>>>>>>>>> - goto out;
>>>>>>>>> -
>>>>>>>>> - blocks_per_page = bytes_to_blks(inode, PAGE_SIZE);
>>>>>>>>> -
>>>>>>>>> - /*
>>>>>>>>> - * Map all the blocks into the extent list. This code doesn't try
>>>>>>>>> - * to be very smart.
>>>>>>>>> - */
>>>>>>>>> - probe_block = 0;
>>>>>>>>> - page_no = 0;
>>>>>>>>> - last_block = bytes_to_blks(inode, i_size_read(inode));
>>>>>>>>> - while ((probe_block + blocks_per_page) <= last_block &&
>>>>>>>>> - page_no < sis->max) {
>>>>>>>>> - unsigned block_in_page;
>>>>>>>>> - sector_t first_block;
>>>>>>>>> - sector_t block = 0;
>>>>>>>>> -
>>>>>>>>> - cond_resched();
>>>>>>>>> -
>>>>>>>>> - block = probe_block;
>>>>>>>>> - ret = bmap(inode, &block);
>>>>>>>>> - if (ret)
>>>>>>>>> - goto out;
>>>>>>>>> - if (!block)
>>>>>>>>> - goto bad_bmap;
>>>>>>>>> - first_block = block;
>>>>>>>>> -
>>>>>>>>> - /*
>>>>>>>>> - * It must be PAGE_SIZE aligned on-disk
>>>>>>>>> - */
>>>>>>>>> - if (first_block & (blocks_per_page - 1)) {
>>>>>>>>> - probe_block++;
>>>>>>>>> - goto reprobe;
>>>>>>>>> - }
>>>>>>>>> -
>>>>>>>>> - for (block_in_page = 1; block_in_page < blocks_per_page;
>>>>>>>>> - block_in_page++) {
>>>>>>>>> -
>>>>>>>>> - block = probe_block + block_in_page;
>>>>>>>>> - ret = bmap(inode, &block);
>>>>>>>>> - if (ret)
>>>>>>>>> - goto out;
>>>>>>>>> - if (!block)
>>>>>>>>> - goto bad_bmap;
>>>>>>>>> -
>>>>>>>>> - if (block != first_block + block_in_page) {
>>>>>>>>> - /* Discontiguity */
>>>>>>>>> - probe_block++;
>>>>>>>>> - goto reprobe;
>>>>>>>>> - }
>>>>>>>>> - }
>>>>>>>>> -
>>>>>>>>> - first_block >>= (PAGE_SHIFT - inode->i_blkbits);
>>>>>>>>> - if (page_no) { /* exclude the header page */
>>>>>>>>> - if (first_block < lowest_block)
>>>>>>>>> - lowest_block = first_block;
>>>>>>>>> - if (first_block > highest_block)
>>>>>>>>> - highest_block = first_block;
>>>>>>>>> - }
>>>>>>>>> -
>>>>>>>>> - /*
>>>>>>>>> - * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
>>>>>>>>> - */
>>>>>>>>> - ret = add_swap_extent(sis, page_no, 1, first_block);
>>>>>>>>> - if (ret < 0)
>>>>>>>>> - goto out;
>>>>>>>>> - nr_extents += ret;
>>>>>>>>> - page_no++;
>>>>>>>>> - probe_block += blocks_per_page;
>>>>>>>>> -reprobe:
>>>>>>>>> - continue;
>>>>>>>>> - }
>>>>>>>>> - ret = nr_extents;
>>>>>>>>> - *span = 1 + highest_block - lowest_block;
>>>>>>>>> - if (page_no == 0)
>>>>>>>>> - page_no = 1; /* force Empty message */
>>>>>>>>> - sis->max = page_no;
>>>>>>>>> - sis->pages = page_no - 1;
>>>>>>>>> - sis->highest_bit = page_no - 1;
>>>>>>>>> -out:
>>>>>>>>> - return ret;
>>>>>>>>> -bad_bmap:
>>>>>>>>> - f2fs_err(sbi, "Swapfile has holes\n");
>>>>>>>>> - return -EINVAL;
>>>>>>>>> -}
>>>>>>>>> -
>>>>>>>>> static int f2fs_swap_activate(struct swap_info_struct *sis, struct file *file,
>>>>>>>>> sector_t *span)
>>>>>>>>> {
>>>>>>>>> --
>>>>>>>>> 2.29.2
>>>>>> .
>>>>>>
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