[PATCH 2/2] f2fs: fix error path of f2fs_remount()

From: Chao Yu
Date: Wed Mar 17 2021 - 05:57:25 EST


In error path of f2fs_remount(), it missed to restart/stop kernel thread
or enable/disable checkpoint, then mount option status may not be
consistent with real condition of filesystem, so let's reorder remount
flow a bit as below and do recovery correctly in error path:

1) handle gc thread
2) handle ckpt thread
3) handle flush thread
4) handle checkpoint disabling

Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
---
fs/f2fs/super.c | 47 ++++++++++++++++++++++++++++++++++-------------
1 file changed, 34 insertions(+), 13 deletions(-)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 6716af216dca..fa60f08c30bb 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1942,8 +1942,9 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
struct f2fs_mount_info org_mount_opt;
unsigned long old_sb_flags;
int err;
- bool need_restart_gc = false;
- bool need_stop_gc = false;
+ bool need_restart_gc = false, need_stop_gc = false;
+ bool need_restart_ckpt = false, need_stop_ckpt = false;
+ bool need_restart_flush = false, need_stop_flush = false;
bool no_extent_cache = !test_opt(sbi, EXTENT_CACHE);
bool disable_checkpoint = test_opt(sbi, DISABLE_CHECKPOINT);
bool no_io_align = !F2FS_IO_ALIGNED(sbi);
@@ -2081,19 +2082,10 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
clear_sbi_flag(sbi, SBI_IS_CLOSE);
}

- if (checkpoint_changed) {
- if (test_opt(sbi, DISABLE_CHECKPOINT)) {
- err = f2fs_disable_checkpoint(sbi);
- if (err)
- goto restore_gc;
- } else {
- f2fs_enable_checkpoint(sbi);
- }
- }
-
if ((*flags & SB_RDONLY) || test_opt(sbi, DISABLE_CHECKPOINT) ||
!test_opt(sbi, MERGE_CHECKPOINT)) {
f2fs_stop_ckpt_thread(sbi);
+ need_restart_ckpt = true;
} else {
err = f2fs_start_ckpt_thread(sbi);
if (err) {
@@ -2102,6 +2094,7 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
err);
goto restore_gc;
}
+ need_stop_ckpt = true;
}

/*
@@ -2111,11 +2104,24 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
if ((*flags & SB_RDONLY) || !test_opt(sbi, FLUSH_MERGE)) {
clear_opt(sbi, FLUSH_MERGE);
f2fs_destroy_flush_cmd_control(sbi, false);
+ need_restart_flush = true;
} else {
err = f2fs_create_flush_cmd_control(sbi);
if (err)
- goto restore_gc;
+ goto restore_ckpt;
+ need_stop_flush = true;
}
+
+ if (checkpoint_changed) {
+ if (test_opt(sbi, DISABLE_CHECKPOINT)) {
+ err = f2fs_disable_checkpoint(sbi);
+ if (err)
+ goto restore_flush;
+ } else {
+ f2fs_enable_checkpoint(sbi);
+ }
+ }
+
skip:
#ifdef CONFIG_QUOTA
/* Release old quota file names */
@@ -2130,6 +2136,21 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
adjust_unusable_cap_perc(sbi);
*flags = (*flags & ~SB_LAZYTIME) | (sb->s_flags & SB_LAZYTIME);
return 0;
+restore_flush:
+ if (need_restart_flush) {
+ if (f2fs_create_flush_cmd_control(sbi))
+ f2fs_warn(sbi, "background flush thread has stopped");
+ } else if (need_stop_flush) {
+ clear_opt(sbi, FLUSH_MERGE);
+ f2fs_destroy_flush_cmd_control(sbi, false);
+ }
+restore_ckpt:
+ if (need_restart_ckpt) {
+ if (f2fs_start_ckpt_thread(sbi))
+ f2fs_warn(sbi, "background ckpt thread has stopped");
+ } else if (need_stop_ckpt) {
+ f2fs_stop_ckpt_thread(sbi);
+ }
restore_gc:
if (need_restart_gc) {
if (f2fs_start_gc_thread(sbi))
--
2.29.2