Hi He, On Tue, Aug 04, 2015 at 09:16:21PM +0800, He YunLei wrote: > On 2015/7/31 18:49, Chao Yu wrote: > > Hi Bintian, > > > >> -----Original Message----- > >> From: He YunLei [mailto:heyun...@huawei.com] > >> Sent: Friday, July 31, 2015 10:29 AM > >> To: linux-f2fs-devel@lists.sourceforge.net; Jaegeuk Kim > >> Cc: Chao Yu; cm224....@samsung.com; Bintian > >> Subject: [f2fs-dev] Data lost in Android app for not write new checkpoint > >> > >> Hi all, > >> Recently I did some test with f2fs on my Android phone, and found a > >> problem > >> which I didn't know how to tackle it. > >> I use my Android phone with /data partition formatted by mkfs.f2fs. > >> When the > >> phone just started, I check the f2fs status by reading the file > >> /sys/kernel/debug/f2fs/status > >> in debugfs. > >> > >> CP calls: 10 > >> GC calls: 19 (BG: 19) > >> - data segments : 19 (19) > >> - node segments : 0 (0) > >> > >> We can see /data partition has done 10 times write_checkpoint since > >> f2fs is mounted > >> on the phone, it also has triggered 19 times background GC. > >> > >> ****** > >> > >> Here I took some photos consecutively, and check the file > >> /sys/kernel/debug/f2fs/status again > >> > >> ****** > >> > >> CP calls: 10 > >> GC calls: 20 (BG: 20) > >> - data segments : 20 (20) > >> - node segments : 0 (0) > >> > >> there is no change in CP calls number and background GC doesn't write > >> new checkpoint. > >> if then a sudden power failure or system crash occur, the photos will be > >> lost when the phone > >> restart, and a sync before crash will avoid the data lost. > >> I think this problem is bad for user experience of using Android phone > >> with f2fs. > >> How do we deal with such situation? I wish you and other developers in > >> this list could help > >> me in a correct way. > > > > IMO, it's better to figure out whether this is a bug of f2fs first or not. > > > > You can enable some traces in f2fs to see whether fsync is called or not. > > > > enable trace by: > > echo 1 > /sys/kernel/debug/tracing/events/f2fs/f2fs_sync_file_enter/enable > > echo 1 > /sys/kernel/debug/tracing/events/f2fs/f2fs_sync_file_exit/enable > > print trace by: > > cat /sys/kernel/debug/tracing/trace > > > > If fsync is not be called, I think in ext4 there must be the same problem, > > but I guess fortunately journal commit thread save its data since it commit > > transaction per 5 second by default. You can try to configure (commit=nrsec) > > it with larger value for verification the issue with ext4 filesystem. > > > > I enable the event xxx_sync_file_enter both in f2fs and ext4, and find > neither of > them was triggered by photo files. > > Then I try f2fs_writepages and ext4_da_write_pages: > > ino file_name > > 65573 IMG_20150804_031619.jpg > 65575 IMG_20150804_031619_1.jpg > 65576 IMG_20150804_031620.jpg > 65577 IMG_20150804_031620_1.jpg > > ext4_da_write_pages: dev 259,0 ino 65573 b_blocknr 0 b_size 0 b_state > 0x0000 first_page 0 io_done 0 pages_written 0 sync_mode 0 > ext4_da_write_pages: dev 259,0 ino 65575 b_blocknr 0 b_size 2408448 b_state > 0x0221 first_page 0 io_done 1 pages_written 588 sync_mode 0 > ext4_da_write_pages: dev 259,0 ino 65575 b_blocknr 0 b_size 0 b_state > 0x0000 first_page 0 io_done 0 pages_written 0 sync_mode 0 > ext4_da_write_pages: dev 259,0 ino 65576 b_blocknr 0 b_size 2428928 b_state > 0x0221 first_page 0 io_done 1 pages_written 593 sync_mode 0 > ext4_da_write_pages: dev 259,0 ino 65576 b_blocknr 0 b_size 0 b_state > 0x0000 first_page 0 io_done 0 pages_written 0 sync_mode 0 > ext4_da_write_pages: dev 259,0 ino 65577 b_blocknr 0 b_size 2383872 b_state > 0x0221 first_page 0 io_done 1 pages_written 582 sync_mode 0 > ext4_da_write_pages: dev 259,0 ino 65577 b_blocknr 0 b_size 0 b_state > 0x0000 first_page 0 io_done 0 pages_written 0 sync_mode 0 > > f2fs_writepages doesn't appear in the test of f2fs
Could you check the submitted IOs from block layer? > > I also try modify commit=300(default 5), but it doesn't work. Maybe somewhere > else in ext4 > launch the ext4_da_write_pages operation. > > At the end, I try to mount f2fs with disable_roll_forward, when system > reboot, the f2fs is inconsistent, > there are several failed check items in fsck. The disable_roll_forward should not be related to any inconsistency. Could you share the log provided by fsck? Thanks, > > Thanks, > He > > > As a quick thought, maybe we can add one commit data thread, periodically > > writebacking user data written by user previously, then do checkpoint for > > persistence. > > > > So by this way, at most, we just lose our data for last configured time of > > commit period. > > > > Thanks, > > > >> > >> Thanks, > >> He > > > > > > > > . > > > > > ------------------------------------------------------------------------------ > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel ------------------------------------------------------------------------------ _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
