OK, details as I explained before:

atomic_commit                           GC
- file_write_and_wait_range
                                        - move_data_block
                                         - f2fs_submit_page_write
                                          - f2fs_update_data_blkaddr
                                           - set_page_dirty
  - fsync_node_pages

1. atomic writes data page #1 & update node #1
2. GC data page #2 & update node #2
3. page #1 & node #1 & #2 can be committed into nand flash before page #2 be
committed.

After a sudden pow-cut, database transaction will be inconsistent. So I think
there will be better to exclude gc/atomic_write to each other, with a lock
instead of flag checking.


I do not understand why this transaction is inconsistent, is it a
problem that page #2 is not committed into nand flash? Since normal
gc also has this problem:

Suppose that there is db file A, f2fs_gc moves data page #1 of db file
A. But if write checkpoint only commit node page #1 and then a sudden
power-cut happens. Data page #1 is not committed to nand flash, but
node page #1 is committed. Is the db transaction broken and
inconsistent?

Come back to your example, I think data page 2 of atomic file does not
belong to this transaction, so even node page 2 is committed, it is just
the same problem as what I have listed above(db file A), and it does not
break this transaction.

Thanks,


So how about just using dio_rwsem[WRITE] during atomic committing to exclude
GCing data block of atomic opened file?

Thanks,


Signed-off-by: Yunlong Song <yunlong.s...@huawei.com>
---
    fs/f2fs/data.c | 5 ++---
    fs/f2fs/gc.c   | 6 ++++--
    2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 7435830..edafcb6 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1580,14 +1580,13 @@ bool should_update_outplace(struct inode *inode, struct 
f2fs_io_info *fio)
                return true;
        if (S_ISDIR(inode->i_mode))
                return true;
-       if (f2fs_is_atomic_file(inode))
-               return true;
        if (fio) {
                if (is_cold_data(fio->page))
                        return true;
                if (IS_ATOMIC_WRITTEN_PAGE(fio->page))
                        return true;
-       }
+       } else if (f2fs_is_atomic_file(inode))
+               return true;
        return false;
    }
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index b9d93fd..84ab3ff 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -622,7 +622,8 @@ 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))
+       if (f2fs_is_atomic_file(inode) &&
+               !f2fs_is_commit_atomic_write(inode))
                goto out;
if (f2fs_is_pinned_file(inode)) {
@@ -729,7 +730,8 @@ 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))
+       if (f2fs_is_atomic_file(inode) &&
+               !f2fs_is_commit_atomic_write(inode))
                goto out;
        if (f2fs_is_pinned_file(inode)) {
                if (gc_type == FG_GC)


.




.




.


--
Thanks,
Yunlong Song


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