[PATCH v2] f2fs: stop gc/discard thread in prior during umount

Chao Yu
2017-06-29T15:20:28Z

From: Chao Yu <yuchao0@huawei.com>

This patch resolves kernel panic for xfstests/081, caused by recent f2fs_bug_on

f2fs: add f2fs_bug_on in __remove_discard_cmd

For fixing, we will stop gc/discard thread in prior in ->kill_sb in order to
avoid referring and releasing race among them.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
---
fs/f2fs/f2fs.h | 1 +
fs/f2fs/segment.c | 19 +++++++++++++------
fs/f2fs/super.c | 7 ++++---
3 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index c27a6264d9bf..da7edb605180 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2288,6 +2288,7 @@ void destroy_flush_cmd_control(struct f2fs_sb_info *sbi, bool free);
void invalidate_blocks(struct f2fs_sb_info *sbi, block_t addr);
bool is_checkpointed_data(struct f2fs_sb_info *sbi, block_t blkaddr);
void refresh_sit_entry(struct f2fs_sb_info *sbi, block_t old, block_t new);
+void stop_discard_thread(struct f2fs_sb_info *sbi);
void f2fs_wait_discard_bios(struct f2fs_sb_info *sbi);
void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc);
void release_discard_addrs(struct f2fs_sb_info *sbi);
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 86a0c1095939..1b22b6b4081c 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1063,6 +1063,18 @@ void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr)
__wait_one_discard_bio(sbi, dc);
}

+void stop_discard_thread(struct f2fs_sb_info *sbi)
+{
+ struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+
+ if (dcc && dcc->f2fs_issue_discard) {
+ struct task_struct *discard_thread = dcc->f2fs_issue_discard;
+
+ dcc->f2fs_issue_discard = NULL;
+ kthread_stop(discard_thread);
+ }
+}
+
/* This comes from f2fs_put_super */
void f2fs_wait_discard_bios(struct f2fs_sb_info *sbi)
{
@@ -1420,12 +1432,7 @@ static void destroy_discard_cmd_control(struct f2fs_sb_info *sbi)
if (!dcc)
return;

- if (dcc->f2fs_issue_discard) {
- struct task_struct *discard_thread = dcc->f2fs_issue_discard;
-
- dcc->f2fs_issue_discard = NULL;
- kthread_stop(discard_thread);
- }
+ stop_discard_thread(sbi);

kfree(dcc);
SM_I(sbi)->dcc_info = NULL;
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 3da6fb276f8b..0a0af82e4dd4 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -566,8 +566,6 @@ static void f2fs_put_super(struct super_block *sb)
struct f2fs_sb_info *sbi = F2FS_SB(sb);
int i;

- stop_gc_thread(sbi);
-
/* prevent remaining shrinker jobs */
mutex_lock(&sbi->umount_mutex);

@@ -1974,8 +1972,11 @@ static struct dentry *f2fs_mount(struct file_system_type *fs_type, int flags,

static void kill_f2fs_super(struct super_block *sb)
{
- if (sb->s_root)
+ if (sb->s_root) {
set_sbi_flag(F2FS_SB(sb), SBI_IS_CLOSE);
+ stop_gc_thread(F2FS_SB(sb));
+ stop_discard_thread(F2FS_SB(sb));
+ }
kill_block_super(sb);
}

--
2.13.0.90.g1eb437020