Messages in this thread Patch in this message | | | Subject | Re: [PATCH] f2fs: let f2fs also gc atomic file to avoid loop gc | From | Yunlong Song <> | Date | Fri, 17 Nov 2017 11:04:36 +0800 |
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The atomic commit will trigger: -f2fs_do_sync_file(filp, 0, LLONG_MAX, 0, true) -file_write_and_wait_range(file, 0, LLONG_MAX) -fsync_node_pages -__write_node_page -REQ_PREFLUSH | REQ_FUA
So data is flushed to non-volatile before last node write with REQ_PREFLUSH | REQ_FUA, we do not need to worry about the inconsistent problem. Right?
On 2017/11/17 10:49, Chao Yu wrote: > On 2017/11/17 8:58, Yunlong Song wrote: >> Is there any problem if just deleting the judgement condition in this patch? > IIRC, dirty node comes from data segment GC can be writebacked & flushed during > atomic commit, but related data will still be in inner bio cache, after later > SPOR, data would be inconsistent. > > Thanks, > >> On 2017/11/8 17:28, Chao Yu wrote: >>> On 2017/11/8 10:34, Yunlong Song wrote: >>>> If some files are opened with atomic flag and have not commited yet, at >>>> the same time, if all the target victim segments have at least one page >>>> of these atomic files, then f2fs gc will fail to do gc and hangs in the >>>> process of go to gc_more, since gc_date_segment will not move any data >>>> and get_valid_blocks will never be 0, then do_garbage_collect will >>>> always return 0. >>> Oh, I added this judgment condition to avoid ruining atomic write by data >>> GC, could we find another way to solve this issue? BTW, if there is direct >>> IO, we will also skip data segment GC. >>> >>> Thanks, >>> >>>> Signed-off-by: Yunlong Song <yunlong.song@huawei.com> >>>> --- >>>> fs/f2fs/gc.c | 6 ------ >>>> 1 file changed, 6 deletions(-) >>>> >>>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c >>>> index 5d5bba4..3fdcd04 100644 >>>> --- a/fs/f2fs/gc.c >>>> +++ b/fs/f2fs/gc.c >>>> @@ -621,9 +621,6 @@ static void move_data_block(struct inode *inode, block_t bidx, >>>> if (!check_valid_map(F2FS_I_SB(inode), segno, off)) >>>> goto out; >>>> >>>> - if (f2fs_is_atomic_file(inode)) >>>> - goto out; >>>> - >>>> set_new_dnode(&dn, inode, NULL, NULL, 0); >>>> err = get_dnode_of_data(&dn, bidx, LOOKUP_NODE); >>>> if (err) >>>> @@ -718,9 +715,6 @@ static void move_data_page(struct inode *inode, block_t bidx, int gc_type, >>>> if (!check_valid_map(F2FS_I_SB(inode), segno, off)) >>>> goto out; >>>> >>>> - if (f2fs_is_atomic_file(inode)) >>>> - goto out; >>>> - >>>> if (gc_type == BG_GC) { >>>> if (PageWriteback(page)) >>>> goto out; >>>> >>> . >>> > > . >
-- Thanks, Yunlong Song
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