[f2fs-dev] [PATCH 1/2] f2fs: flush pending checkpoints when freezing super

[f2fs-dev] [PATCH 1/2] f2fs: flush pending checkpoints when freezing super

[Jaegeuk Kim]

This avoids -EINVAL when trying to freeze f2fs.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/checkpoint.c | 27 +++++++++++++++++++++------
 fs/f2fs/f2fs.h       |  1 +
 fs/f2fs/super.c      |  5 ++---
 3 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 8259e0fa97e1..37f7a9ea4746 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1892,15 +1892,30 @@ int f2fs_start_ckpt_thread(struct f2fs_sb_info *sbi)
 void f2fs_stop_ckpt_thread(struct f2fs_sb_info *sbi)
 {
 	struct ckpt_req_control *cprc = &sbi->cprc_info;
+	struct task_struct *ckpt_task;
 
-	if (cprc->f2fs_issue_ckpt) {
-		struct task_struct *ckpt_task = cprc->f2fs_issue_ckpt;
+	if (!cprc->f2fs_issue_ckpt)
+		return;
 
-		cprc->f2fs_issue_ckpt = NULL;
-		kthread_stop(ckpt_task);
+	ckpt_task = cprc->f2fs_issue_ckpt;
+	cprc->f2fs_issue_ckpt = NULL;
+	kthread_stop(ckpt_task);
 
-		flush_remained_ckpt_reqs(sbi, NULL);
-	}
+	f2fs_flush_ckpt_thread(sbi);
+}
+
+void f2fs_flush_ckpt_thread(struct f2fs_sb_info *sbi)
+{
+	struct ckpt_req_control *cprc = &sbi->cprc_info;
+
+	if (!cprc->f2fs_issue_ckpt)
+		return;
+
+	flush_remained_ckpt_reqs(sbi, NULL);
+
+	/* Let's wait for the previous dispatched checkpoint. */
+	while (atomic_read(&cprc->queued_ckpt))
+		io_schedule_timeout(DEFAULT_IO_TIMEOUT);
 }
 
 void f2fs_init_ckpt_req_control(struct f2fs_sb_info *sbi)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 3c7cdb70fe2e..2a83fc34b372 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3707,6 +3707,7 @@ static inline bool f2fs_need_rand_seg(struct f2fs_sb_info *sbi)
  * checkpoint.c
  */
 void f2fs_stop_checkpoint(struct f2fs_sb_info *sbi, bool end_io);
+void f2fs_flush_ckpt_thread(struct f2fs_sb_info *sbi);
 struct page *f2fs_grab_meta_page(struct f2fs_sb_info *sbi, pgoff_t index);
 struct page *f2fs_get_meta_page(struct f2fs_sb_info *sbi, pgoff_t index);
 struct page *f2fs_get_meta_page_retry(struct f2fs_sb_info *sbi, pgoff_t index);
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 212ec2b4926b..48ac3de4a533 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1670,9 +1670,8 @@ static int f2fs_freeze(struct super_block *sb)
 	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;
+	/* Let's flush checkpoints and stop the thread. */
+	f2fs_flush_ckpt_thread(F2FS_SB(sb));
 
 	/* to avoid deadlock on f2fs_evict_inode->SB_FREEZE_FS */
 	set_sbi_flag(F2FS_SB(sb), SBI_IS_FREEZING);
-- 
2.37.1.595.g718a3a8f04-goog



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[f2fs-dev] [PATCH 2/2] f2fs: complete checkpoints during remount

[Jaegeuk Kim]

Otherwise, pending checkpoints can contribute a race condition to give a
quota warning.

- Thread                      - checkpoint thread
                              add checkpoints to the list
do_remount()
 down_write(&sb->s_umount);
 f2fs_remount()
                              block_operations()
                               down_read_trylock(&sb->s_umount) = 0
 up_write(&sb->s_umount);
                               f2fs_quota_sync()
                                dquot_writeback_dquots()
                                 WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/super.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 48ac3de4a533..88879c483805 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2349,6 +2349,9 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
 		f2fs_stop_ckpt_thread(sbi);
 		need_restart_ckpt = true;
 	} else {
+		/* flush if the prevous checkpoint, if exists. */
+		f2fs_flush_ckpt_thread(sbi);
+
 		err = f2fs_start_ckpt_thread(sbi);
 		if (err) {
 			f2fs_err(sbi,
-- 
2.37.1.595.g718a3a8f04-goog



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Re: [f2fs-dev] [PATCH 1/2] f2fs: flush pending checkpoints when freezing super

[Jaegeuk Kim]

This avoids -EINVAL when trying to freeze f2fs.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---

 Change log from v1:
  - do not check cprc->f2fs_issue_ckpt in f2fs_flush_ckpt_thread

 fs/f2fs/checkpoint.c | 24 ++++++++++++++++++------
 fs/f2fs/f2fs.h       |  1 +
 fs/f2fs/super.c      |  5 ++---
 3 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 7de48e791920..7bf1feb5ac78 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1893,15 +1893,27 @@ int f2fs_start_ckpt_thread(struct f2fs_sb_info *sbi)
 void f2fs_stop_ckpt_thread(struct f2fs_sb_info *sbi)
 {
 	struct ckpt_req_control *cprc = &sbi->cprc_info;
+	struct task_struct *ckpt_task;
 
-	if (cprc->f2fs_issue_ckpt) {
-		struct task_struct *ckpt_task = cprc->f2fs_issue_ckpt;
+	if (!cprc->f2fs_issue_ckpt)
+		return;
 
-		cprc->f2fs_issue_ckpt = NULL;
-		kthread_stop(ckpt_task);
+	ckpt_task = cprc->f2fs_issue_ckpt;
+	cprc->f2fs_issue_ckpt = NULL;
+	kthread_stop(ckpt_task);
 
-		flush_remained_ckpt_reqs(sbi, NULL);
-	}
+	f2fs_flush_ckpt_thread(sbi);
+}
+
+void f2fs_flush_ckpt_thread(struct f2fs_sb_info *sbi)
+{
+	struct ckpt_req_control *cprc = &sbi->cprc_info;
+
+	flush_remained_ckpt_reqs(sbi, NULL);
+
+	/* Let's wait for the previous dispatched checkpoint. */
+	while (atomic_read(&cprc->queued_ckpt))
+		io_schedule_timeout(DEFAULT_IO_TIMEOUT);
 }
 
 void f2fs_init_ckpt_req_control(struct f2fs_sb_info *sbi)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 6770210aae70..088c3d1574b8 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3711,6 +3711,7 @@ static inline bool f2fs_need_rand_seg(struct f2fs_sb_info *sbi)
  * checkpoint.c
  */
 void f2fs_stop_checkpoint(struct f2fs_sb_info *sbi, bool end_io);
+void f2fs_flush_ckpt_thread(struct f2fs_sb_info *sbi);
 struct page *f2fs_grab_meta_page(struct f2fs_sb_info *sbi, pgoff_t index);
 struct page *f2fs_get_meta_page(struct f2fs_sb_info *sbi, pgoff_t index);
 struct page *f2fs_get_meta_page_retry(struct f2fs_sb_info *sbi, pgoff_t index);
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index e910f0e39d76..4f2ff50b247c 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1671,9 +1671,8 @@ static int f2fs_freeze(struct super_block *sb)
 	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;
+	/* Let's flush checkpoints and stop the thread. */
+	f2fs_flush_ckpt_thread(F2FS_SB(sb));
 
 	/* to avoid deadlock on f2fs_evict_inode->SB_FREEZE_FS */
 	set_sbi_flag(F2FS_SB(sb), SBI_IS_FREEZING);
-- 
2.37.1.595.g718a3a8f04-goog



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Re: [f2fs-dev] [PATCH 2/2 v2] f2fs: complete checkpoints during remount

[Jaegeuk Kim]

Otherwise, pending checkpoints can contribute a race condition to give a
quota warning.

- Thread                      - checkpoint thread
                              add checkpoints to the list
do_remount()
 down_write(&sb->s_umount);
 f2fs_remount()
                              block_operations()
                               down_read_trylock(&sb->s_umount) = 0
 up_write(&sb->s_umount);
                               f2fs_quota_sync()
                                dquot_writeback_dquots()
                                 WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));

Or,

do_remount()
 down_write(&sb->s_umount);
 f2fs_remount()
                              create a ckpt thread
                              f2fs_enable_checkpoint() adds checkpoints
			      wait for f2fs_sync_fs()
                              trigger another pending checkpoint
                               block_operations()
                                down_read_trylock(&sb->s_umount) = 0
 up_write(&sb->s_umount);
                                f2fs_quota_sync()
                                 dquot_writeback_dquots()
                                  WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---

 Change log from v1:
  - add one more case

 fs/f2fs/super.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 4f2ff50b247c..0f29c759a898 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2185,6 +2185,9 @@ static void f2fs_enable_checkpoint(struct f2fs_sb_info *sbi)
 	f2fs_up_write(&sbi->gc_lock);
 
 	f2fs_sync_fs(sbi->sb, 1);
+
+	/* Let's ensure there's no pending checkpoint anymore */
+	f2fs_flush_ckpt_thread(sbi);
 }
 
 static int f2fs_remount(struct super_block *sb, int *flags, char *data)
@@ -2350,6 +2353,9 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
 		f2fs_stop_ckpt_thread(sbi);
 		need_restart_ckpt = true;
 	} else {
+		/* Flush if the prevous checkpoint, if exists. */
+		f2fs_flush_ckpt_thread(sbi);
+
 		err = f2fs_start_ckpt_thread(sbi);
 		if (err) {
 			f2fs_err(sbi,
-- 
2.37.1.595.g718a3a8f04-goog



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Re: [f2fs-dev] [PATCH 1/2] f2fs: flush pending checkpoints when freezing super

[Chao Yu]

On 2022/8/25 4:02, Jaegeuk Kim wrote:
> This avoids -EINVAL when trying to freeze f2fs.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,


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Re: [f2fs-dev] [PATCH 2/2 v2] f2fs: complete checkpoints during remount

[Chao Yu]

On 2022/8/25 4:30, Jaegeuk Kim wrote:
> Otherwise, pending checkpoints can contribute a race condition to give a
> quota warning.
> 
> - Thread                      - checkpoint thread
>                                add checkpoints to the list
> do_remount()
>   down_write(&sb->s_umount);
>   f2fs_remount()
>                                block_operations()
>                                 down_read_trylock(&sb->s_umount) = 0
>   up_write(&sb->s_umount);
>                                 f2fs_quota_sync()
>                                  dquot_writeback_dquots()
>                                   WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));
> 
> Or,
> 
> do_remount()
>   down_write(&sb->s_umount);
>   f2fs_remount()
>                                create a ckpt thread
>                                f2fs_enable_checkpoint() adds checkpoints
> 			      wait for f2fs_sync_fs()
>                                trigger another pending checkpoint
>                                 block_operations()
>                                  down_read_trylock(&sb->s_umount) = 0
>   up_write(&sb->s_umount);
>                                  f2fs_quota_sync()
>                                   dquot_writeback_dquots()
>                                    WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,


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