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Message-ID: <ZELkf+5mC1XuAwIN@google.com>
Date: Fri, 21 Apr 2023 12:31:11 -0700
From: Jaegeuk Kim <jaegeuk@...nel.org>
To: Chao Yu <chao@...nel.org>
Cc: linux-f2fs-devel@...ts.sourceforge.net,
linux-kernel@...r.kernel.org, Yangtao Li <frank.li@...o.com>
Subject: Re: [PATCH v8] f2fs: support errors=remount-ro|continue|panic
mountoption
On 04/21, Chao Yu wrote:
> On 2023/4/21 0:34, Jaegeuk Kim wrote:
> > On 04/20, Chao Yu wrote:
> > > On 2023/4/20 4:19, Jaegeuk Kim wrote:
> > > > On 04/08, Chao Yu wrote:
> > > > > This patch supports errors=remount-ro|continue|panic mount option,
> > > > > by default it uses "remount-ro" mode.
> > > > >
> > > > > Signed-off-by: Chao Yu <chao@...nel.org>
> > > > > Signed-off-by: Yangtao Li <frank.li@...o.com>
> > > > > ---
> > > > > v8:
> > > > > - record stop reason synchronously if it's from ioctl shutdown interface
> > > > > - fix typo in doc and commit message.
> > > > > - use f2fs_hw_is_readonly() instead of bdev_read_only()
> > > > > Documentation/filesystems/f2fs.rst | 5 ++
> > > > > fs/f2fs/checkpoint.c | 7 +-
> > > > > fs/f2fs/f2fs.h | 20 ++++-
> > > > > fs/f2fs/file.c | 5 --
> > > > > fs/f2fs/gc.c | 2 +-
> > > > > fs/f2fs/super.c | 134 ++++++++++++++++++++++++++---
> > > > > 6 files changed, 149 insertions(+), 24 deletions(-)
> > > > >
> > > > > diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst
> > > > > index 2055e72871fe..ba4c02fad647 100644
> > > > > --- a/Documentation/filesystems/f2fs.rst
> > > > > +++ b/Documentation/filesystems/f2fs.rst
> > > > > @@ -351,6 +351,11 @@ age_extent_cache Enable an age extent cache based on rb-tree. It records
> > > > > data block update frequency of the extent per inode, in
> > > > > order to provide better temperature hints for data block
> > > > > allocation.
> > > > > +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. By default it uses "remount-ro"
> > > > > + mode.
> > > > > ======================== ============================================================
> > > > > Debugfs Entries
> > > > > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> > > > > index 73ae4e85e70d..e6b266bb9ce0 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 ac4942f8e83e..7d9c5a65f974 100644
> > > > > --- a/fs/f2fs/f2fs.h
> > > > > +++ b/fs/f2fs/f2fs.h
> > > > > @@ -162,6 +162,7 @@ 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,
> > > > > @@ -1370,6 +1371,12 @@ 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);
> > > > > static inline void f2fs_clear_bit(unsigned int nr, char *addr);
> > > > > @@ -1786,8 +1793,14 @@ struct f2fs_sb_info {
> > > > > struct workqueue_struct *post_read_wq; /* post read workqueue */
> > > > > - unsigned char errors[MAX_F2FS_ERRORS]; /* error flags */
> > > > > - spinlock_t error_lock; /* protect errors array */
> > > > > + /*
> > > > > + * 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/stop_reason array */
> > > > > bool error_dirty; /* errors of sb is dirty */
> > > > > struct kmem_cache *inline_xattr_slab; /* inline xattr entry */
> > > > > @@ -3522,8 +3535,9 @@ 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_save_errors(struct f2fs_sb_info *sbi, unsigned char flag);
> > > > > +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 14e9a20e68df..10743e864d57 100644
> > > > > --- a/fs/f2fs/file.c
> > > > > +++ b/fs/f2fs/file.c
> > > > > @@ -2221,7 +2221,6 @@ 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);
> > > > > trace_f2fs_shutdown(sbi, in, ret);
> > > > > }
> > > > > return ret;
> > > > > @@ -2234,7 +2233,6 @@ 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:
> > > > > @@ -2243,16 +2241,13 @@ 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/gc.c b/fs/f2fs/gc.c
> > > > > index f1d0dd9c5a6c..6dc2bc710ba8 100644
> > > > > --- a/fs/f2fs/gc.c
> > > > > +++ b/fs/f2fs/gc.c
> > > > > @@ -59,7 +59,7 @@ static int gc_thread_func(void *data)
> > > > > if (gc_th->gc_wake)
> > > > > gc_th->gc_wake = false;
> > > > > - if (try_to_freeze()) {
> > > > > + if (try_to_freeze() || f2fs_readonly(sbi->sb)) {
> > > > > stat_other_skip_bggc_count(sbi);
> > > > > continue;
> > > > > }
> > > > > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > > > > index 23574894e170..1573bf123197 100644
> > > > > --- a/fs/f2fs/super.c
> > > > > +++ b/fs/f2fs/super.c
> > > > > @@ -164,6 +164,7 @@ enum {
> > > > > Opt_discard_unit,
> > > > > Opt_memory_mode,
> > > > > Opt_age_extent_cache,
> > > > > + Opt_errors,
> > > > > Opt_err,
> > > > > };
> > > > > @@ -243,6 +244,7 @@ static match_table_t f2fs_tokens = {
> > > > > {Opt_discard_unit, "discard_unit=%s"},
> > > > > {Opt_memory_mode, "memory=%s"},
> > > > > {Opt_age_extent_cache, "age_extent_cache"},
> > > > > + {Opt_errors, "errors=%s"},
> > > > > {Opt_err, NULL},
> > > > > };
> > > > > @@ -1268,6 +1270,25 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount)
> > > > > case Opt_age_extent_cache:
> > > > > set_opt(sbi, AGE_EXTENT_CACHE);
> > > > > 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);
> > > > > @@ -1623,6 +1644,9 @@ static void f2fs_put_super(struct super_block *sb)
> > > > > f2fs_destroy_node_manager(sbi);
> > > > > f2fs_destroy_segment_manager(sbi);
> > > > > + /* flush s_error_work before sbi destroy */
> > > > > + flush_work(&sbi->s_error_work);
> > > > > +
> > > > > f2fs_destroy_post_read_wq(sbi);
> > > > > kvfree(sbi->ckpt);
> > > > > @@ -2053,6 +2077,13 @@ 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;
> > > > > }
> > > > > @@ -2081,6 +2112,7 @@ static void default_options(struct f2fs_sb_info *sbi)
> > > > > }
> > > > > F2FS_OPTION(sbi).bggc_mode = BGGC_MODE_ON;
> > > > > F2FS_OPTION(sbi).memory_mode = MEMORY_MODE_NORMAL;
> > > > > + F2FS_OPTION(sbi).errors = MOUNT_ERRORS_READONLY;
> > > >
> > > > Was the default MOUNT_ERRORS_CONTINUE?
> > >
> > > Okay, let me revise in v9.
> > >
> > > Please note that main difference between continue mode and readonly mode once
> > > cp_error is set:
> > >
> > > continue mode readonly mode
> > > access ops: Normal Normal
> > > modify ops: -EIO -EROFS
> > > mount option rw ro
> >
> > Could you please add the difference of all the modes in patch description?
> >
> > I think it'd be good to add:
> > 1. access ops
> > 2. syscall errors
> > 3. mount option
> > 4. pending data writes
> > 5. pending node writes
> > 6. pending meta writes
>
> Sure, I'd like to add below description into f2fs.rst, any comments?
>
> continue remount-ro panic
> access ops normal noraml N/A
> syscall errors -EIO -EROFS N/A
> mount option rw ro N/A
So the only difference is the above two, as in any cases, we won't flush pending
pages at all? What about keeping nondir/node pages in the remount-ro case
differently?
> pending dir write keep keep N/A
> pending nondir write drop drop N/A
> pending node write drop drop N/A
> pending meta write keep keep N/A
>
> Thanks,
>
> >
> >
> > >
> > > Thanks,
> > >
> > > >
> > > > > sbi->sb->s_flags &= ~SB_INLINECRYPT;
> > > > > @@ -2282,6 +2314,9 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
> > > > > if (err)
> > > > > goto restore_opts;
> > > > > + /* flush outstanding errors before changing fs state */
> > > > > + flush_work(&sbi->s_error_work);
> > > > > +
> > > > > /*
> > > > > * Previous and new state of filesystem is RO,
> > > > > * so skip checking GC and FLUSH_MERGE conditions.
> > > > > @@ -3931,45 +3966,60 @@ 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)
> > > > > +{
> > > > > + unsigned long flags;
> > > > > +
> > > > > + spin_lock_irqsave(&sbi->error_lock, flags);
> > > > > + if (sbi->stop_reason[reason] < GENMASK(BITS_PER_BYTE - 1, 0))
> > > > > + sbi->stop_reason[reason]++;
> > > > > + spin_unlock_irqrestore(&sbi->error_lock, flags);
> > > > > +}
> > > > > +
> > > > > +static void f2fs_record_stop_reason(struct f2fs_sb_info *sbi)
> > > > > {
> > > > > struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
> > > > > + unsigned long flags;
> > > > > int err;
> > > > > f2fs_down_write(&sbi->sb_lock);
> > > > > - if (raw_super->s_stop_reason[reason] < GENMASK(BITS_PER_BYTE - 1, 0))
> > > > > - raw_super->s_stop_reason[reason]++;
> > > > > + spin_lock_irqsave(&sbi->error_lock, flags);
> > > > > + memcpy(raw_super->s_stop_reason, sbi->stop_reason, MAX_STOP_REASON);
> > > > > + spin_unlock_irqrestore(&sbi->error_lock, flags);
> > > > > 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);
> > > > > }
> > > > > void f2fs_save_errors(struct f2fs_sb_info *sbi, unsigned char flag)
> > > > > {
> > > > > - spin_lock(&sbi->error_lock);
> > > > > + unsigned long flags;
> > > > > +
> > > > > + spin_lock_irqsave(&sbi->error_lock, flags);
> > > > > if (!test_bit(flag, (unsigned long *)sbi->errors)) {
> > > > > set_bit(flag, (unsigned long *)sbi->errors);
> > > > > sbi->error_dirty = true;
> > > > > }
> > > > > - spin_unlock(&sbi->error_lock);
> > > > > + spin_unlock_irqrestore(&sbi->error_lock, flags);
> > > > > }
> > > > > static bool f2fs_update_errors(struct f2fs_sb_info *sbi)
> > > > > {
> > > > > + unsigned long flags;
> > > > > bool need_update = false;
> > > > > - spin_lock(&sbi->error_lock);
> > > > > + spin_lock_irqsave(&sbi->error_lock, flags);
> > > > > if (sbi->error_dirty) {
> > > > > memcpy(F2FS_RAW_SUPER(sbi)->s_errors, sbi->errors,
> > > > > MAX_F2FS_ERRORS);
> > > > > sbi->error_dirty = false;
> > > > > need_update = true;
> > > > > }
> > > > > - spin_unlock(&sbi->error_lock);
> > > > > + spin_unlock_irqrestore(&sbi->error_lock, flags);
> > > > > return need_update;
> > > > > }
> > > > > @@ -3993,6 +4043,66 @@ 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;
> > > > > +
> > > > > + set_ckpt_flags(sbi, CP_ERROR_FLAG);
> > > > > +
> > > > > + if (!f2fs_hw_is_readonly(sbi)) {
> > > > > + save_stop_reason(sbi, reason);
> > > > > +
> > > > > + if (irq_context && !shutdown)
> > > > > + 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;
> > > > > +}
> > > > > +
> > > > > +static void f2fs_record_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);
> > > > > @@ -4223,7 +4333,9 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
> > > > > sb->s_fs_info = sbi;
> > > > > sbi->raw_super = raw_super;
> > > > > + INIT_WORK(&sbi->s_error_work, f2fs_record_error_work);
> > > > > memcpy(sbi->errors, raw_super->s_errors, MAX_F2FS_ERRORS);
> > > > > + memcpy(sbi->stop_reason, raw_super->s_stop_reason, MAX_STOP_REASON);
> > > > > /* precompute checksum seed for metadata */
> > > > > if (f2fs_sb_has_inode_chksum(sbi))
> > > > > @@ -4620,6 +4732,8 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
> > > > > f2fs_destroy_segment_manager(sbi);
> > > > > stop_ckpt_thread:
> > > > > f2fs_stop_ckpt_thread(sbi);
> > > > > + /* flush s_error_work before sbi destroy */
> > > > > + flush_work(&sbi->s_error_work);
> > > > > f2fs_destroy_post_read_wq(sbi);
> > > > > free_devices:
> > > > > destroy_device_list(sbi);
> > > > > --
> > > > > 2.36.1
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