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authorChao Yu <yuchao0@huawei.com>2017-10-02 02:50:16 +0800
committerJaegeuk Kim <jaegeuk@kernel.org>2017-10-03 08:06:05 -0700
commit638164a2718f337ea224b747cf5977ef143166a4 (patch)
treeeb00daa4d3fea717977c5bea6caf3f6d08726031 /fs/f2fs/super.c
parente365806ac289457263a133bd32df8df49897f612 (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/super.c')
-rw-r--r--fs/f2fs/super.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 89f61eb3d167..933c3d529e65 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -801,7 +801,7 @@ static void f2fs_put_super(struct super_block *sb)
}
/* be sure to wait for any on-going discard commands */
- f2fs_wait_discard_bios(sbi);
+ f2fs_wait_discard_bios(sbi, true);
if (f2fs_discard_en(sbi) && !sbi->discard_blks) {
struct cp_control cpc = {