On 07/23, Chao Yu wrote:
> On 2019/7/23 9:27, Jaegeuk Kim wrote:
> > On 07/18, Chao Yu wrote:
> >> On 2019/7/18 12:00, Jaegeuk Kim wrote:
> >>> On 07/18, Chao Yu wrote:
> >>>> On 2019/7/18 11:12, Jaegeuk Kim wrote:
> >>>>> f2fs_allocate_data_block() invalidates old block address and enable new
> >>>>> block
> >>>>> address. Then, if we try to read old block by f2fs_submit_page_bio(),
> >>>>> it will
> >>>>> give WARN due to reading invalid blocks.
> >>>>>
> >>>>> Let's make the order sanely back.
> >>>>
> >>>> Hmm.. to avoid WARM, we may suffer one more memcpy, I suspect this can
> >>>> reduce
> >>>> online resize or foreground gc ioctl performance...
> >>>
> >>> I worried about performance tho, more concern came to me that there may
> >>> exist a
> >>> chance that other thread can allocate and write something in old block
> >>> address.
> >>
> >> Me too, however, previous invalid block address should be reused after a
> >> checkpoint, and checkpoint should have invalidated meta cache already, so
> >> there
> >> shouldn't be any race here.
> >
> > I think SSR can reuse that before checkpoint.
>
> Yes, I should have considered that when I introduced readahead feature for
> migration of block, we've kept invalidating meta page cache in old block
> address
> whenever the block address is not valid.
>
> quoted from ("f2fs: readahead encrypted block during GC")
>
> "Note that for OPU, truncation, deletion, we need to invalid meta
> page after we invalid old block address, to make sure we won't load
> invalid data from target meta page during encrypted block migration."
>
> But to avoid potential issue, how about just enable meta page cache during GC?
> that is saying we should truncate all valid meta cache after one section has
> been moved.
We may need to invalidate metapage when writing new data, which looks like
different issue.
>
> One more concern is whether below case exists during SSR?
> - write 4k to fileA;
> - fsync fileA, 4k data is writebacked to lbaA;
> - write 4k to fileA;
> - kworker flushs 4k to lbaB; dnode contain lbaB didn't be persisted yet;
> - write 4k to fileB;
> - kworker flush 4k to lbaA due to SSR;
> - SPOR -> dnode with lbaA will be recovered, however lbaA contains fileB's
> data..
Yes, it seems that's possible. We may need to keep another bitmap to record
all the block allocation?
>
> Thanks,
>
> >
> >>
> >> /*
> >> * invalidate intermediate page cache borrowed from meta inode
> >> * which are used for migration of encrypted inode's blocks.
> >> */
> >> if (f2fs_sb_has_encrypt(sbi))
> >> invalidate_mapping_pages(META_MAPPING(sbi),
> >> MAIN_BLKADDR(sbi), MAX_BLKADDR(sbi) - 1);
> >>
> >> Thanks,
> >>
> >>>
> >>>>
> >>>> Can we just relief to use DATA_GENERIC_ENHANCE_READ for this case...?
> >>>
> >>> We need to keep consistency for this api.
> >>>
> >>> Thanks,
> >>>
> >>>>
> >>>>>
> >>>>> Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org>
> >>>>
> >>>> Except performance, I'm okay with this change.
> >>>>
> >>>> Reviewed-by: Chao Yu <yuch...@huawei.com>
> >>>>
> >>>> Thanks,
> >>>>
> >>>>> ---
> >>>>> v2:
> >>>>> I was fixing the comments. :)
> >>>>>
> >>>>> fs/f2fs/gc.c | 70 +++++++++++++++++++++++++---------------------------
> >>>>> 1 file changed, 34 insertions(+), 36 deletions(-)
> >>>>>
> >>>>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> >>>>> index 6691f526fa40..8974672db78f 100644
> >>>>> --- a/fs/f2fs/gc.c
> >>>>> +++ b/fs/f2fs/gc.c
> >>>>> @@ -796,6 +796,29 @@ static int move_data_block(struct inode *inode,
> >>>>> block_t bidx,
> >>>>> if (lfs_mode)
> >>>>> down_write(&fio.sbi->io_order_lock);
> >>>>>
> >>>>> + mpage = f2fs_grab_cache_page(META_MAPPING(fio.sbi),
> >>>>> + fio.old_blkaddr, false);
> >>>>> + if (!mpage)
> >>>>> + goto up_out;
> >>>>> +
> >>>>> + fio.encrypted_page = mpage;
> >>>>> +
> >>>>> + /* read source block in mpage */
> >>>>> + if (!PageUptodate(mpage)) {
> >>>>> + err = f2fs_submit_page_bio(&fio);
> >>>>> + if (err) {
> >>>>> + f2fs_put_page(mpage, 1);
> >>>>> + goto up_out;
> >>>>> + }
> >>>>> + lock_page(mpage);
> >>>>> + if (unlikely(mpage->mapping != META_MAPPING(fio.sbi) ||
> >>>>> + !PageUptodate(mpage))) {
> >>>>> + err = -EIO;
> >>>>> + f2fs_put_page(mpage, 1);
> >>>>> + goto up_out;
> >>>>> + }
> >>>>> + }
> >>>>> +
> >>>>> f2fs_allocate_data_block(fio.sbi, NULL, fio.old_blkaddr,
> >>>>> &newaddr,
> >>>>> &sum, CURSEG_COLD_DATA, NULL,
> >>>>> false);
> >>>>>
> >>>>> @@ -803,44 +826,18 @@ static int move_data_block(struct inode *inode,
> >>>>> block_t bidx,
> >>>>> newaddr, FGP_LOCK | FGP_CREAT,
> >>>>> GFP_NOFS);
> >>>>> if (!fio.encrypted_page) {
> >>>>> err = -ENOMEM;
> >>>>> - goto recover_block;
> >>>>> - }
> >>>>> -
> >>>>> - mpage = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
> >>>>> - fio.old_blkaddr, FGP_LOCK,
> >>>>> GFP_NOFS);
> >>>>> - if (mpage) {
> >>>>> - bool updated = false;
> >>>>> -
> >>>>> - if (PageUptodate(mpage)) {
> >>>>> - memcpy(page_address(fio.encrypted_page),
> >>>>> - page_address(mpage), PAGE_SIZE);
> >>>>> - updated = true;
> >>>>> - }
> >>>>> f2fs_put_page(mpage, 1);
> >>>>> - invalidate_mapping_pages(META_MAPPING(fio.sbi),
> >>>>> - fio.old_blkaddr,
> >>>>> fio.old_blkaddr);
> >>>>> - if (updated)
> >>>>> - goto write_page;
> >>>>> - }
> >>>>> -
> >>>>> - err = f2fs_submit_page_bio(&fio);
> >>>>> - if (err)
> >>>>> - goto put_page_out;
> >>>>> -
> >>>>> - /* write page */
> >>>>> - lock_page(fio.encrypted_page);
> >>>>> -
> >>>>> - if (unlikely(fio.encrypted_page->mapping !=
> >>>>> META_MAPPING(fio.sbi))) {
> >>>>> - err = -EIO;
> >>>>> - goto put_page_out;
> >>>>> - }
> >>>>> - if (unlikely(!PageUptodate(fio.encrypted_page))) {
> >>>>> - err = -EIO;
> >>>>> - goto put_page_out;
> >>>>> + goto recover_block;
> >>>>> }
> >>>>>
> >>>>> -write_page:
> >>>>> + /* write target block */
> >>>>> f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true,
> >>>>> true);
> >>>>> + memcpy(page_address(fio.encrypted_page),
> >>>>> + page_address(mpage), PAGE_SIZE);
> >>>>> + f2fs_put_page(mpage, 1);
> >>>>> + invalidate_mapping_pages(META_MAPPING(fio.sbi),
> >>>>> + fio.old_blkaddr, fio.old_blkaddr);
> >>>>> +
> >>>>> set_page_dirty(fio.encrypted_page);
> >>>>> if (clear_page_dirty_for_io(fio.encrypted_page))
> >>>>> dec_page_count(fio.sbi, F2FS_DIRTY_META);
> >>>>> @@ -871,11 +868,12 @@ static int move_data_block(struct inode *inode,
> >>>>> block_t bidx,
> >>>>> put_page_out:
> >>>>> f2fs_put_page(fio.encrypted_page, 1);
> >>>>> recover_block:
> >>>>> - if (lfs_mode)
> >>>>> - up_write(&fio.sbi->io_order_lock);
> >>>>> if (err)
> >>>>> f2fs_do_replace_block(fio.sbi, &sum, newaddr,
> >>>>> fio.old_blkaddr,
> >>>>> true,
> >>>>> true);
> >>>>> +up_out:
> >>>>> + if (lfs_mode)
> >>>>> + up_write(&fio.sbi->io_order_lock);
> >>>>> put_out:
> >>>>> f2fs_put_dnode(&dn);
> >>>>> out:
> >>>>>
> >>>>
> >>>>
> >>>> _______________________________________________
> >>>> Linux-f2fs-devel mailing list
> >>>> Linux-f2fs-devel@lists.sourceforge.net
> >>>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
> >>> .
> >>>
> > .
> >
