diff options
| author | Chao Yu <yuchao0@huawei.com> | 2017-10-02 02:50:16 +0800 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2017-10-03 08:06:05 -0700 |
| commit | 638164a2718f337ea224b747cf5977ef143166a4 (patch) | |
| tree | eb00daa4d3fea717977c5bea6caf3f6d08726031 /fs/f2fs/segment.c | |
| parent | e365806ac289457263a133bd32df8df49897f612 (diff) | |
f2fs: fix potential panic during fstrim
As Ju Hyung Park reported:
"When 'fstrim' is called for manual trim, a BUG() can be triggered
randomly with this patch.
I'm seeing this issue on both x86 Desktop and arm64 Android phone.
On x86 Desktop, this was caused during Ubuntu boot-up. I have a
cronjob installed which calls 'fstrim -v /' during boot. On arm64
Android, this was caused during GC looping with 1ms gc_min_sleep_time
& gc_max_sleep_time."
Root cause of this issue is that f2fs_wait_discard_bios can only be
used by f2fs_put_super, because during put_super there must be no
other referrers, so it can ignore discard entry's reference count
when removing the entry, otherwise in other caller we will hit bug_on
in __remove_discard_cmd as there may be other issuer added reference
count in discard entry.
Thread A Thread B
- issue_discard_thread
- f2fs_ioc_fitrim
- f2fs_trim_fs
- f2fs_wait_discard_bios
- __issue_discard_cmd
- __submit_discard_cmd
- __wait_discard_cmd
- dc->ref++
- __wait_one_discard_bio
- __wait_discard_cmd
- __remove_discard_cmd
- f2fs_bug_on(sbi, dc->ref)
Fixes: 969d1b180d987c2be02de890d0fff0f66a0e80de
Reported-by: Ju Hyung Park <qkrwngud825@gmail.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs/segment.c')
| -rw-r--r-- | fs/f2fs/segment.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 621b9b3d320b..c695ff462ee6 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -1210,11 +1210,11 @@ void stop_discard_thread(struct f2fs_sb_info *sbi) } /* This comes from f2fs_put_super and f2fs_trim_fs */ -void f2fs_wait_discard_bios(struct f2fs_sb_info *sbi) +void f2fs_wait_discard_bios(struct f2fs_sb_info *sbi, bool umount) { __issue_discard_cmd(sbi, false); __drop_discard_cmd(sbi); - __wait_discard_cmd(sbi, false); + __wait_discard_cmd(sbi, !umount); } static void mark_discard_range_all(struct f2fs_sb_info *sbi) @@ -2244,7 +2244,7 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range) } /* It's time to issue all the filed discards */ mark_discard_range_all(sbi); - f2fs_wait_discard_bios(sbi); + f2fs_wait_discard_bios(sbi, false); out: range->len = F2FS_BLK_TO_BYTES(cpc.trimmed); return err; |