Messages in this thread | | | Subject | Re: [PATCH] f2fs: add fi->commit_lock to protect commit GCed pages | From | Chao Yu <> | Date | Fri, 9 Feb 2018 20:44:05 +0800 |
| |
On 2018/2/8 11:11, Yunlong Song wrote: > Then the GCed data pages are totally mixed with the inmem atomic pages,
If we add dio_rwsem, GC flow is exclude with atomic write flow. There will be not race case to mix GCed page into atomic pages.
Or you mean:
- gc_data_segment - move_data_page - f2fs_is_atomic_file - f2fs_ioc_start_atomic_write - set_inode_flag(inode, FI_ATOMIC_FILE); - f2fs_set_data_page_dirty - register_inmem_page
In this case, GCed page can be mixed into database transaction, but could it cause any problem except break rule of isolation for transaction.
> this will cause the atomic commit ops write the GCed data pages twice > (the first write happens in GC). > > How about using the early two patches to separate the inmem data pages > and GCed data pages, and use dio_rwsem instead of this patch to fix the > dnode page problem (dnode page commited but data page are not committed > for the GCed page)?
Could we fix the race case first, based on that fixing, and then find the place that we can improve?
> > > On 2018/2/7 20:16, Chao Yu wrote: >> On 2018/2/6 11:49, Yunlong Song wrote: >>> This patch adds fi->commit_lock to avoid the case that GCed node pages >>> are committed but GCed data pages are not committed. This can avoid the >>> db file run into inconsistent state when sudden-power-off happens if >>> data pages of atomic file is allowed to be GCed before. >> >> do_fsync: GC: >> - mutex_lock(&fi->commit_lock); >> - lock_page() >> - mutex_lock(&fi->commit_lock); >> - lock_page() >> >> >> Well, please consider lock dependency & code complexity, IMO, reuse >> fi->dio_rwsem[WRITE] will be enough as below: >> >> --- >> fs/f2fs/file.c | 3 +++ >> fs/f2fs/gc.c | 5 ----- >> 2 files changed, 3 insertions(+), 5 deletions(-) >> >> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c >> index 672a542e5464..1bdc11feb8d0 100644 >> --- a/fs/f2fs/file.c >> +++ b/fs/f2fs/file.c >> @@ -1711,6 +1711,8 @@ static int f2fs_ioc_commit_atomic_write(struct file *filp) >> >> inode_lock(inode); >> >> + down_write(&F2FS_I(inode)->dio_rwsem[WRITE]); >> + >> if (f2fs_is_volatile_file(inode)) >> goto err_out; >> >> @@ -1729,6 +1731,7 @@ static int f2fs_ioc_commit_atomic_write(struct file *filp) >> ret = f2fs_do_sync_file(filp, 0, LLONG_MAX, 1, false); >> } >> err_out: >> + up_write(&F2FS_I(inode)->dio_rwsem[WRITE]); >> inode_unlock(inode); >> mnt_drop_write_file(filp); >> return ret; >> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c >> index b9d93fd532a9..e49416283563 100644 >> --- a/fs/f2fs/gc.c >> +++ b/fs/f2fs/gc.c >> @@ -622,9 +622,6 @@ 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;
Seems that we need this check.
>> - >> if (f2fs_is_pinned_file(inode)) { >> f2fs_pin_file_control(inode, true); >> goto out; >> @@ -729,8 +726,6 @@ 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;
Ditto.
Thanks,
>> if (f2fs_is_pinned_file(inode)) { >> if (gc_type == FG_GC) >> f2fs_pin_file_control(inode, true); >> >
| |