Re: [PATCH v3] f2fs: support errors=remount-ro|continue|panic mountoption

Jaegeuk Kim
2022-10-05T22:09:03Z

On 10/05, Chao Yu wrote:
> On 2022/10/5 4:28, Jaegeuk Kim wrote:
> > On 10/04, Chao Yu wrote:
> > > This patch supports errors=remount-ro|continue|panic mount option.
> > >
> > > Signed-off-by: Chao Yu <chao@kernel.org>
> > > ---
> > > - clean up codes
> > > - stop gc/discard threads after remount fs as readonly
> > > - don't panic() after f2fs is shutdown
> > > Documentation/filesystems/f2fs.rst | 4 +
> > > fs/f2fs/checkpoint.c | 7 +-
> > > fs/f2fs/f2fs.h | 18 ++++-
> > > fs/f2fs/file.c | 5 --
> > > fs/f2fs/super.c | 116 +++++++++++++++++++++++++++--
> > > 5 files changed, 131 insertions(+), 19 deletions(-)
> > >
> > > diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst
> > > index d0c09663dae8..6f19e7f9e908 100644
> > > --- a/Documentation/filesystems/f2fs.rst
> > > +++ b/Documentation/filesystems/f2fs.rst
> > > @@ -341,6 +341,10 @@ memory=%s Control memory mode. This supports "normal" and "low" modes.
> > > Because of the nature of low memory devices, in this mode, f2fs
> > > will try to save memory sometimes by sacrificing performance.
> > > "normal" mode is the default mode and same as before.
> > > +errors=%s Specify f2fs behavior on critical errors. This supports modes:
> > > + "panic", "continue" and "remount-ro", respectively, trigger
> > > + panic immediately, continue without doing anything, and remount
> > > + the partition in read-only mode (default behavior).
> > > ======================== ============================================================
> > > Debugfs Entries
> > > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> > > index 0c82dae082aa..109e96c15b84 100644
> > > --- a/fs/f2fs/checkpoint.c
> > > +++ b/fs/f2fs/checkpoint.c
> > > @@ -30,12 +30,9 @@ void f2fs_stop_checkpoint(struct f2fs_sb_info *sbi, bool end_io,
> > > unsigned char reason)
> > > {
> > > f2fs_build_fault_attr(sbi, 0, 0);
> > > - set_ckpt_flags(sbi, CP_ERROR_FLAG);
> > > - if (!end_io) {
> > > + if (!end_io)
> > > f2fs_flush_merged_writes(sbi);
> > > -
> > > - f2fs_handle_stop(sbi, reason);
> > > - }
> > > + f2fs_handle_critical_error(sbi, reason, end_io);
> > > }
> > > /*
> > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > > index a0b2c8626a75..40c8e28f41ba 100644
> > > --- a/fs/f2fs/f2fs.h
> > > +++ b/fs/f2fs/f2fs.h
> > > @@ -160,6 +160,7 @@ struct f2fs_mount_info {
> > > int fs_mode; /* fs mode: LFS or ADAPTIVE */
> > > int bggc_mode; /* bggc mode: off, on or sync */
> > > int memory_mode; /* memory mode */
> > > + int errors; /* errors parameter */
> > > int discard_unit; /*
> > > * discard command's offset/size should
> > > * be aligned to this unit: block,
> > > @@ -1382,7 +1383,11 @@ enum {
> > > MEMORY_MODE_LOW, /* memory mode for low memry devices */
> > > };
> > > -
> > > +enum errors_option {
> > > + MOUNT_ERRORS_READONLY, /* remount fs ro on errors */
> > > + MOUNT_ERRORS_CONTINUE, /* continue on errors */
> > > + MOUNT_ERRORS_PANIC, /* panic on errors */
> > > +};
> > > static inline int f2fs_test_bit(unsigned int nr, char *addr);
> > > static inline void f2fs_set_bit(unsigned int nr, char *addr);
> > > @@ -1818,7 +1823,13 @@ struct f2fs_sb_info {
> > > struct workqueue_struct *post_read_wq; /* post read workqueue */
> > > - unsigned char errors[MAX_F2FS_ERRORS]; /* error flags */
> > > + /*
> > > + * If we are in irq context, let's update error information into
> > > + * on-disk superblock in the work.
> > > + */
> > > + struct work_struct s_error_work;
> > > + unsigned char errors[MAX_F2FS_ERRORS]; /* error flags */
> > > + unsigned char stop_reason[MAX_STOP_REASON]; /* stop reason */
> > > spinlock_t error_lock; /* protect errors array */
> > > bool error_dirty; /* errors of sb is dirty */
> > > @@ -3563,7 +3574,8 @@ int f2fs_enable_quota_files(struct f2fs_sb_info *sbi, bool rdonly);
> > > int f2fs_quota_sync(struct super_block *sb, int type);
> > > loff_t max_file_blocks(struct inode *inode);
> > > void f2fs_quota_off_umount(struct super_block *sb);
> > > -void f2fs_handle_stop(struct f2fs_sb_info *sbi, unsigned char reason);
> > > +void f2fs_handle_critical_error(struct f2fs_sb_info *sbi, unsigned char reason,
> > > + bool irq_context);
> > > void f2fs_handle_error(struct f2fs_sb_info *sbi, unsigned char error);
> > > int f2fs_commit_super(struct f2fs_sb_info *sbi, bool recover);
> > > int f2fs_sync_fs(struct super_block *sb, int sync);
> > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > > index df5e7ad80096..acda670df676 100644
> > > --- a/fs/f2fs/file.c
> > > +++ b/fs/f2fs/file.c
> > > @@ -2157,7 +2157,6 @@ static int f2fs_ioc_shutdown(struct file *filp, unsigned long arg)
> > > ret = 0;
> > > f2fs_stop_checkpoint(sbi, false,
> > > STOP_CP_REASON_SHUTDOWN);
> > > - set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
> >
> > What about keeping this and bypassing panic if this is set?
>
> Please check below code, it processes like you suggested:

Gotcha.

>
> + if (F2FS_OPTION(sbi).errors == MOUNT_ERRORS_PANIC &&
> + !shutdown && !system_going_down() &&
> + !is_sbi_flag_set(sbi, SBI_IS_SHUTDOWN))
> + panic("F2FS-fs (device %s): panic forced after error\n",
> + sb->s_id);
> +
> + if (shutdown)
> + set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
>
> Thanks,
>
> >
> > > trace_f2fs_shutdown(sbi, in, ret);
> > > }
> > > return ret;
> > > @@ -2170,7 +2169,6 @@ static int f2fs_ioc_shutdown(struct file *filp, unsigned long arg)
> > > if (ret)
> > > goto out;
> > > f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_SHUTDOWN);
> > > - set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
> > > thaw_bdev(sb->s_bdev);
> > > break;
> > > case F2FS_GOING_DOWN_METASYNC:
> > > @@ -2179,16 +2177,13 @@ static int f2fs_ioc_shutdown(struct file *filp, unsigned long arg)
> > > if (ret)
> > > goto out;
> > > f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_SHUTDOWN);
> > > - set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
> > > break;
> > > case F2FS_GOING_DOWN_NOSYNC:
> > > f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_SHUTDOWN);
> > > - set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
> > > break;
> > > case F2FS_GOING_DOWN_METAFLUSH:
> > > f2fs_sync_meta_pages(sbi, META, LONG_MAX, FS_META_IO);
> > > f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_SHUTDOWN);
> > > - set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
> > > break;
> > > case F2FS_GOING_DOWN_NEED_FSCK:
> > > set_sbi_flag(sbi, SBI_NEED_FSCK);
> > > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > > index 6cf72fbf2054..787010893a12 100644
> > > --- a/fs/f2fs/super.c
> > > +++ b/fs/f2fs/super.c
> > > @@ -161,6 +161,7 @@ enum {
> > > Opt_nogc_merge,
> > > Opt_discard_unit,
> > > Opt_memory_mode,
> > > + Opt_errors,
> > > Opt_err,
> > > };
> > > @@ -238,6 +239,7 @@ static match_table_t f2fs_tokens = {
> > > {Opt_nogc_merge, "nogc_merge"},
> > > {Opt_discard_unit, "discard_unit=%s"},
> > > {Opt_memory_mode, "memory=%s"},
> > > + {Opt_errors, "errors=%s"},
> > > {Opt_err, NULL},
> > > };
> > > @@ -1253,6 +1255,25 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount)
> > > }
> > > kfree(name);
> > > break;
> > > + case Opt_errors:
> > > + name = match_strdup(&args[0]);
> > > + if (!name)
> > > + return -ENOMEM;
> > > + if (!strcmp(name, "remount-ro")) {
> > > + F2FS_OPTION(sbi).errors =
> > > + MOUNT_ERRORS_READONLY;
> > > + } else if (!strcmp(name, "continue")) {
> > > + F2FS_OPTION(sbi).errors =
> > > + MOUNT_ERRORS_CONTINUE;
> > > + } else if (!strcmp(name, "panic")) {
> > > + F2FS_OPTION(sbi).errors =
> > > + MOUNT_ERRORS_PANIC;
> > > + } else {
> > > + kfree(name);
> > > + return -EINVAL;
> > > + }
> > > + kfree(name);
> > > + break;
> > > default:
> > > f2fs_err(sbi, "Unrecognized mount option \"%s\" or missing value",
> > > p);
> > > @@ -2031,6 +2052,13 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
> > > else if (F2FS_OPTION(sbi).memory_mode == MEMORY_MODE_LOW)
> > > seq_printf(seq, ",memory=%s", "low");
> > > + if (F2FS_OPTION(sbi).errors == MOUNT_ERRORS_READONLY)
> > > + seq_printf(seq, ",errors=%s", "remount-ro");
> > > + else if (F2FS_OPTION(sbi).errors == MOUNT_ERRORS_CONTINUE)
> > > + seq_printf(seq, ",errors=%s", "continue");
> > > + else if (F2FS_OPTION(sbi).errors == MOUNT_ERRORS_PANIC)
> > > + seq_printf(seq, ",errors=%s", "panic");
> > > +
> > > return 0;
> > > }
> > > @@ -2053,6 +2081,7 @@ static void default_options(struct f2fs_sb_info *sbi)
> > > F2FS_OPTION(sbi).compress_mode = COMPR_MODE_FS;
> > > F2FS_OPTION(sbi).bggc_mode = BGGC_MODE_ON;
> > > F2FS_OPTION(sbi).memory_mode = MEMORY_MODE_NORMAL;
> > > + F2FS_OPTION(sbi).errors = MOUNT_ERRORS_READONLY;
> > > sbi->sb->s_flags &= ~SB_INLINECRYPT;
> > > @@ -3846,21 +3875,30 @@ int f2fs_commit_super(struct f2fs_sb_info *sbi, bool recover)
> > > return err;
> > > }
> > > -void f2fs_handle_stop(struct f2fs_sb_info *sbi, unsigned char reason)
> > > +static void save_stop_reason(struct f2fs_sb_info *sbi, unsigned char reason)
> > > +{
> > > + spin_lock(&sbi->error_lock);
> > > + if (sbi->stop_reason[reason] < ((1 << BITS_PER_BYTE) - 1))
> > > + sbi->stop_reason[reason]++;
> > > + spin_unlock(&sbi->error_lock);
> > > +}
> > > +
> > > +void f2fs_record_stop_reason(struct f2fs_sb_info *sbi)
> > > {
> > > struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
> > > int err;
> > > f2fs_down_write(&sbi->sb_lock);
> > > - if (raw_super->s_stop_reason[reason] < ((1 << BITS_PER_BYTE) - 1))
> > > - raw_super->s_stop_reason[reason]++;
> > > + spin_lock(&sbi->error_lock);
> > > + memcpy(raw_super->s_stop_reason, sbi->stop_reason, MAX_STOP_REASON);
> > > + spin_unlock(&sbi->error_lock);
> > > err = f2fs_commit_super(sbi, false);
> > > - if (err)
> > > - f2fs_err(sbi, "f2fs_commit_super fails to record reason:%u err:%d",
> > > - reason, err);
> > > +
> > > f2fs_up_write(&sbi->sb_lock);
> > > + if (err)
> > > + f2fs_err(sbi, "f2fs_commit_super fails to record err:%d", err);
> > > }
> > > static void f2fs_save_errors(struct f2fs_sb_info *sbi, unsigned char flag)
> > > @@ -3908,6 +3946,70 @@ void f2fs_handle_error(struct f2fs_sb_info *sbi, unsigned char error)
> > > f2fs_up_write(&sbi->sb_lock);
> > > }
> > > +static bool system_going_down(void)
> > > +{
> > > + return system_state == SYSTEM_HALT || system_state == SYSTEM_POWER_OFF
> > > + || system_state == SYSTEM_RESTART;
> > > +}
> > > +
> > > +void f2fs_handle_critical_error(struct f2fs_sb_info *sbi, unsigned char reason,
> > > + bool irq_context)
> > > +{
> > > + struct super_block *sb = sbi->sb;
> > > + bool shutdown = reason == STOP_CP_REASON_SHUTDOWN;
> > > + bool continue_fs = !shutdown &&
> > > + F2FS_OPTION(sbi).errors == MOUNT_ERRORS_CONTINUE;
> > > +
> > > + if (!continue_fs && !f2fs_readonly(sb))
> > > + set_ckpt_flags(sbi, CP_ERROR_FLAG);
> > > +
> > > + if (!bdev_read_only(sb->s_bdev)) {
> > > + save_stop_reason(sbi, reason);
> > > +
> > > + if (irq_context)
> > > + schedule_work(&sbi->s_error_work);
> > > + else
> > > + f2fs_record_stop_reason(sbi);
> > > + }
> > > +
> > > + /*
> > > + * We force ERRORS_RO behavior when system is rebooting. Otherwise we
> > > + * could panic during 'reboot -f' as the underlying device got already
> > > + * disabled.
> > > + */
> > > + if (F2FS_OPTION(sbi).errors == MOUNT_ERRORS_PANIC &&
> > > + !shutdown && !system_going_down() &&
> > > + !is_sbi_flag_set(sbi, SBI_IS_SHUTDOWN))
> > > + panic("F2FS-fs (device %s): panic forced after error\n",
> > > + sb->s_id);
> > > +
> > > + if (shutdown)
> > > + set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
> > > +
> > > + /* continue filesystem operators if errors=continue */
> > > + if (continue_fs || f2fs_readonly(sb))
> > > + return;
> > > +
> > > + f2fs_warn(sbi, "Remounting filesystem read-only");
> > > + /*
> > > + * Make sure updated value of ->s_mount_flags will be visible before
> > > + * ->s_flags update
> > > + */
> > > + smp_wmb();
> > > + sb->s_flags |= SB_RDONLY;
> > > +
> > > + f2fs_stop_gc_thread(sbi);
> > > + f2fs_stop_discard_thread(sbi);
> > > +}
> > > +
> > > +static void flush_error_work(struct work_struct *work)
> > > +{
> > > + struct f2fs_sb_info *sbi = container_of(work,
> > > + struct f2fs_sb_info, s_error_work);
> > > +
> > > + f2fs_record_stop_reason(sbi);
> > > +}
> > > +
> > > static int f2fs_scan_devices(struct f2fs_sb_info *sbi)
> > > {
> > > struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
> > > @@ -4255,8 +4357,10 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
> > > goto free_devices;
> > > }
> > > + INIT_WORK(&sbi->s_error_work, flush_error_work);
> > > spin_lock_init(&sbi->error_lock);
> > > memcpy(sbi->errors, raw_super->s_errors, MAX_F2FS_ERRORS);
> > > + memcpy(sbi->stop_reason, raw_super->s_stop_reason, MAX_STOP_REASON);
> > > sbi->total_valid_node_count =
> > > le32_to_cpu(sbi->ckpt->valid_node_count);
> > > --
> > > 2.36.1