f2fs: checkpoint disabling
Note that, it requires "f2fs: return correct errno in f2fs_gc".
This adds a lightweight non-persistent snapshotting scheme to f2fs.
To use, mount with the option checkpoint=disable, and to return to
normal operation, remount with checkpoint=enable. If the filesystem
is shut down before remounting with checkpoint=enable, it will revert
back to its apparent state when it was first mounted with
checkpoint=disable. This is useful for situations where you wish to be
able to roll back the state of the disk in case of some critical
failure.
Signed-off-by: Daniel Rosenberg <drosen@google.com>
[Jaegeuk Kim: use SB_RDONLY instead of MS_RDONLY]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index a449132..19933d8 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -136,6 +136,7 @@ enum {
Opt_alloc,
Opt_fsync,
Opt_test_dummy_encryption,
+ Opt_checkpoint,
Opt_err,
};
@@ -194,6 +195,7 @@ static match_table_t f2fs_tokens = {
{Opt_alloc, "alloc_mode=%s"},
{Opt_fsync, "fsync_mode=%s"},
{Opt_test_dummy_encryption, "test_dummy_encryption"},
+ {Opt_checkpoint, "checkpoint=%s"},
{Opt_err, NULL},
};
@@ -769,6 +771,23 @@ static int parse_options(struct super_block *sb, char *options)
"Test dummy encryption mount option ignored");
#endif
break;
+ case Opt_checkpoint:
+ name = match_strdup(&args[0]);
+ if (!name)
+ return -ENOMEM;
+
+ if (strlen(name) == 6 &&
+ !strncmp(name, "enable", 6)) {
+ clear_opt(sbi, DISABLE_CHECKPOINT);
+ } else if (strlen(name) == 7 &&
+ !strncmp(name, "disable", 7)) {
+ set_opt(sbi, DISABLE_CHECKPOINT);
+ } else {
+ kfree(name);
+ return -EINVAL;
+ }
+ kfree(name);
+ break;
default:
f2fs_msg(sb, KERN_ERR,
"Unrecognized mount option \"%s\" or missing value",
@@ -827,6 +846,12 @@ static int parse_options(struct super_block *sb, char *options)
}
}
+ if (test_opt(sbi, DISABLE_CHECKPOINT) && test_opt(sbi, LFS)) {
+ f2fs_msg(sb, KERN_ERR,
+ "LFS not compatible with checkpoint=disable\n");
+ return -EINVAL;
+ }
+
/* Not pass down write hints if the number of active logs is lesser
* than NR_CURSEG_TYPE.
*/
@@ -1014,8 +1039,8 @@ static void f2fs_put_super(struct super_block *sb)
* But, the previous checkpoint was not done by umount, it needs to do
* clean checkpoint again.
*/
- if (is_sbi_flag_set(sbi, SBI_IS_DIRTY) ||
- !is_set_ckpt_flags(sbi, CP_UMOUNT_FLAG)) {
+ if ((is_sbi_flag_set(sbi, SBI_IS_DIRTY) ||
+ !is_set_ckpt_flags(sbi, CP_UMOUNT_FLAG))) {
struct cp_control cpc = {
.reason = CP_UMOUNT,
};
@@ -1087,6 +1112,8 @@ int f2fs_sync_fs(struct super_block *sb, int sync)
if (unlikely(f2fs_cp_error(sbi)))
return 0;
+ if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED)))
+ return 0;
trace_f2fs_sync_fs(sb, sync);
@@ -1186,6 +1213,11 @@ static int f2fs_statfs(struct dentry *dentry, struct kstatfs *buf)
buf->f_blocks = total_count - start_count;
buf->f_bfree = user_block_count - valid_user_blocks(sbi) -
sbi->current_reserved_blocks;
+ if (unlikely(buf->f_bfree <= sbi->unusable_block_count))
+ buf->f_bfree = 0;
+ else
+ buf->f_bfree -= sbi->unusable_block_count;
+
if (buf->f_bfree > F2FS_OPTION(sbi).root_reserved_blocks)
buf->f_bavail = buf->f_bfree -
F2FS_OPTION(sbi).root_reserved_blocks;
@@ -1365,6 +1397,9 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
else if (F2FS_OPTION(sbi).alloc_mode == ALLOC_MODE_REUSE)
seq_printf(seq, ",alloc_mode=%s", "reuse");
+ if (test_opt(sbi, DISABLE_CHECKPOINT))
+ seq_puts(seq, ",checkpoint=disable");
+
if (F2FS_OPTION(sbi).fsync_mode == FSYNC_MODE_POSIX)
seq_printf(seq, ",fsync_mode=%s", "posix");
else if (F2FS_OPTION(sbi).fsync_mode == FSYNC_MODE_STRICT)
@@ -1392,6 +1427,7 @@ static void default_options(struct f2fs_sb_info *sbi)
set_opt(sbi, INLINE_DENTRY);
set_opt(sbi, EXTENT_CACHE);
set_opt(sbi, NOHEAP);
+ clear_opt(sbi, DISABLE_CHECKPOINT);
sbi->sb->s_flags |= SB_LAZYTIME;
set_opt(sbi, FLUSH_MERGE);
set_opt(sbi, DISCARD);
@@ -1413,6 +1449,57 @@ static void default_options(struct f2fs_sb_info *sbi)
#ifdef CONFIG_QUOTA
static int f2fs_enable_quotas(struct super_block *sb);
#endif
+
+static int f2fs_disable_checkpoint(struct f2fs_sb_info *sbi)
+{
+ struct cp_control cpc;
+ int err;
+
+ sbi->sb->s_flags |= SB_ACTIVE;
+
+ mutex_lock(&sbi->gc_mutex);
+ f2fs_update_time(sbi, DISABLE_TIME);
+
+ while (!f2fs_time_over(sbi, DISABLE_TIME)) {
+ err = f2fs_gc(sbi, true, false, NULL_SEGNO);
+ if (err == -ENODATA)
+ break;
+ if (err && err != -EAGAIN) {
+ mutex_unlock(&sbi->gc_mutex);
+ return err;
+ }
+ }
+ mutex_unlock(&sbi->gc_mutex);
+
+ err = sync_filesystem(sbi->sb);
+ if (err)
+ return err;
+
+ if (f2fs_disable_cp_again(sbi))
+ return -EAGAIN;
+
+ mutex_lock(&sbi->gc_mutex);
+ cpc.reason = CP_PAUSE;
+ set_sbi_flag(sbi, SBI_CP_DISABLED);
+ f2fs_write_checkpoint(sbi, &cpc);
+
+ sbi->unusable_block_count = 0;
+ mutex_unlock(&sbi->gc_mutex);
+ return 0;
+}
+
+static void f2fs_enable_checkpoint(struct f2fs_sb_info *sbi)
+{
+ mutex_lock(&sbi->gc_mutex);
+ f2fs_dirty_to_prefree(sbi);
+
+ clear_sbi_flag(sbi, SBI_CP_DISABLED);
+ set_sbi_flag(sbi, SBI_IS_DIRTY);
+ mutex_unlock(&sbi->gc_mutex);
+
+ f2fs_sync_fs(sbi->sb, 1);
+}
+
static int f2fs_remount(struct super_block *sb, int *flags, char *data)
{
struct f2fs_sb_info *sbi = F2FS_SB(sb);
@@ -1422,6 +1509,8 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
bool need_restart_gc = false;
bool need_stop_gc = false;
bool no_extent_cache = !test_opt(sbi, EXTENT_CACHE);
+ bool disable_checkpoint = test_opt(sbi, DISABLE_CHECKPOINT);
+ bool checkpoint_changed;
#ifdef CONFIG_QUOTA
int i, j;
#endif
@@ -1466,6 +1555,8 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
err = parse_options(sb, data);
if (err)
goto restore_opts;
+ checkpoint_changed =
+ disable_checkpoint != test_opt(sbi, DISABLE_CHECKPOINT);
/*
* Previous and new state of filesystem is RO,
@@ -1479,7 +1570,7 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
err = dquot_suspend(sb, -1);
if (err < 0)
goto restore_opts;
- } else if (f2fs_readonly(sb) && !(*flags & MS_RDONLY)) {
+ } else if (f2fs_readonly(sb) && !(*flags & SB_RDONLY)) {
/* dquot_resume needs RW */
sb->s_flags &= ~SB_RDONLY;
if (sb_any_quota_suspended(sb)) {
@@ -1499,6 +1590,13 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
goto restore_opts;
}
+ if ((*flags & SB_RDONLY) && test_opt(sbi, DISABLE_CHECKPOINT)) {
+ err = -EINVAL;
+ f2fs_msg(sbi->sb, KERN_WARNING,
+ "disabling checkpoint not compatible with read-only");
+ goto restore_opts;
+ }
+
/*
* We stop the GC thread if FS is mounted as RO
* or if background_gc = off is passed in mount
@@ -1527,6 +1625,16 @@ 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);
+ }
+ }
+
/*
* We stop issue flush thread if FS is mounted as RO
* or if flush_merge is not passed in mount option.
@@ -2485,6 +2593,7 @@ static void init_sb_info(struct f2fs_sb_info *sbi)
sbi->interval_time[REQ_TIME] = DEF_IDLE_INTERVAL;
sbi->interval_time[DISCARD_TIME] = DEF_IDLE_INTERVAL;
sbi->interval_time[GC_TIME] = DEF_IDLE_INTERVAL;
+ sbi->interval_time[DISABLE_TIME] = DEF_DISABLE_INTERVAL;
clear_sbi_flag(sbi, SBI_NEED_FSCK);
for (i = 0; i < NR_COUNT_TYPE; i++)
@@ -3093,6 +3202,9 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
if (err)
goto free_meta;
+ if (unlikely(is_set_ckpt_flags(sbi, CP_DISABLED_FLAG)))
+ goto skip_recovery;
+
/* recover fsynced data */
if (!test_opt(sbi, DISABLE_ROLL_FORWARD)) {
/*
@@ -3132,6 +3244,14 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
/* f2fs_recover_fsync_data() cleared this already */
clear_sbi_flag(sbi, SBI_POR_DOING);
+ if (test_opt(sbi, DISABLE_CHECKPOINT)) {
+ err = f2fs_disable_checkpoint(sbi);
+ if (err)
+ goto free_meta;
+ } else if (is_set_ckpt_flags(sbi, CP_DISABLED_FLAG)) {
+ f2fs_enable_checkpoint(sbi);
+ }
+
/*
* If filesystem is not mounted as read-only then
* do start the gc_thread.