[PATCH] f2fs: don't grab superblock freeze for flush/ckpt thread

From: Jaegeuk Kim
Date: Mon Feb 08 2021 - 16:57:29 EST


There are controlled by f2fs_freeze().

This fixes xfstests/generic/068 which is stuck at

task:f2fs_ckpt-252:3 state:D stack: 0 pid: 5761 ppid: 2 flags:0x00004000
Call Trace:
__schedule+0x44c/0x8a0
schedule+0x4f/0xc0
percpu_rwsem_wait+0xd8/0x140
? percpu_down_write+0xf0/0xf0
__percpu_down_read+0x56/0x70
issue_checkpoint_thread+0x12c/0x160 [f2fs]
? wait_woken+0x80/0x80
kthread+0x114/0x150
? __checkpoint_and_complete_reqs+0x110/0x110 [f2fs]
? kthread_park+0x90/0x90
ret_from_fork+0x22/0x30

Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
fs/f2fs/checkpoint.c | 4 ----
fs/f2fs/segment.c | 4 ----
fs/f2fs/super.c | 4 ++++
3 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 579b9c3603cc..174a0819ad96 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1763,13 +1763,9 @@ static int issue_checkpoint_thread(void *data)
if (kthread_should_stop())
return 0;

- sb_start_intwrite(sbi->sb);
-
if (!llist_empty(&cprc->issue_list))
__checkpoint_and_complete_reqs(sbi);

- sb_end_intwrite(sbi->sb);
-
wait_event_interruptible(*q,
kthread_should_stop() || !llist_empty(&cprc->issue_list));
goto repeat;
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 7d34f1cacdee..440634dfaa56 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -607,8 +607,6 @@ static int issue_flush_thread(void *data)
if (kthread_should_stop())
return 0;

- sb_start_intwrite(sbi->sb);
-
if (!llist_empty(&fcc->issue_list)) {
struct flush_cmd *cmd, *next;
int ret;
@@ -629,8 +627,6 @@ static int issue_flush_thread(void *data)
fcc->dispatch_list = NULL;
}

- sb_end_intwrite(sbi->sb);
-
wait_event_interruptible(*q,
kthread_should_stop() || !llist_empty(&fcc->issue_list));
goto repeat;
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 1000d21120ca..4aa533cb4340 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1472,6 +1472,10 @@ static int f2fs_freeze(struct super_block *sb)
/* must be clean, since sync_filesystem() was already called */
if (is_sbi_flag_set(F2FS_SB(sb), SBI_IS_DIRTY))
return -EINVAL;
+
+ /* ensure no checkpoint required */
+ if (!llist_empty(&F2FS_SB(sb)->cprc_info.issue_list))
+ return -EINVAL;
return 0;
}

--
2.30.0.478.g8a0d178c01-goog