[PATCH v4 1/1] f2fs: ioctl for removing a range from F2FS

From: sunqiuyang
Date: Tue May 21 2019 - 23:50:34 EST

From: Qiuyang Sun <sunqiuyang@xxxxxxxxxx>

This ioctl shrinks a given length (aligned to sections) from end of the
main area. Any cursegs and valid blocks will be moved out before
invalidating the range.

This feature can be used for adjusting partition sizes online.
--
Changlog v1 ==> v2:

Sahitya Tummala:
- Add this ioctl for f2fs_compat_ioctl() as well.
- Fix debugfs status to reflect the online resize changes.
- Fix potential race between online resize path and allocate new data
block path or gc path.

Others:
- Rename some identifiers.
- Add some error handling branches.
- Clear sbi->next_victim_seg[BG_GC/FG_GC] in shrinking range.
--
Changelog v2 ==> v3:
Implement this interface as ext4's, and change the parameter from shrunk
bytes to new block count of F2FS.
--
Changelog v3 ==> v4:
- During resizing, force to empty sit_journal and forbid adding new
entries to it, in order to avoid invalid segno in journal after resize.
- Reduce sbi->user_block_count before resize starts.
- Commit the updated superblock first, and then update in-memory metadata
only when the former succeeds.
- Target block count must align to sections.

Signed-off-by: Qiuyang Sun <sunqiuyang@xxxxxxxxxx>
Signed-off-by: Sahitya Tummala <stummala@xxxxxxxxxxxxxx>
---
fs/f2fs/debug.c | 7 +++
fs/f2fs/f2fs.h | 6 +++
fs/f2fs/file.c | 28 +++++++++++
fs/f2fs/gc.c | 137 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
fs/f2fs/segment.c | 43 +++++++++++++----
fs/f2fs/segment.h | 1 +
fs/f2fs/super.c | 3 ++
7 files changed, 214 insertions(+), 11 deletions(-)

diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c
index 99e9a5c..7706049 100644
--- a/fs/f2fs/debug.c
+++ b/fs/f2fs/debug.c
@@ -27,8 +27,15 @@
static void update_general_status(struct f2fs_sb_info *sbi)
{
struct f2fs_stat_info *si = F2FS_STAT(sbi);
+ struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
int i;

+ /* these will be changed if online resize is done */
+ si->main_area_segs = le32_to_cpu(raw_super->segment_count_main);
+ si->main_area_sections = le32_to_cpu(raw_super->section_count);
+ si->main_area_zones = si->main_area_sections /
+ le32_to_cpu(raw_super->secs_per_zone);
+
/* validation check of the segment numbers */
si->hit_largest = atomic64_read(&sbi->read_hit_largest);
si->hit_cached = atomic64_read(&sbi->read_hit_cached);
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index a205d4d..fc53d37 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -423,6 +423,7 @@ static inline bool __has_cursum_space(struct f2fs_journal *journal,
#define F2FS_IOC_SET_PIN_FILE _IOW(F2FS_IOCTL_MAGIC, 13, __u32)
#define F2FS_IOC_GET_PIN_FILE _IOR(F2FS_IOCTL_MAGIC, 14, __u32)
#define F2FS_IOC_PRECACHE_EXTENTS _IO(F2FS_IOCTL_MAGIC, 15)
+#define F2FS_IOC_RESIZE_FS _IOW(F2FS_IOCTL_MAGIC, 16, __u64)

#define F2FS_IOC_SET_ENCRYPTION_POLICY FS_IOC_SET_ENCRYPTION_POLICY
#define F2FS_IOC_GET_ENCRYPTION_POLICY FS_IOC_GET_ENCRYPTION_POLICY
@@ -1309,6 +1310,9 @@ struct f2fs_sb_info {
unsigned int segs_per_sec; /* segments per section */
unsigned int secs_per_zone; /* sections per zone */
unsigned int total_sections; /* total section count */
+ unsigned int current_total_sections; /* for shrink resize */
+ bool resizing;
+ struct mutex resize_mutex;
unsigned int total_node_count; /* total node block count */
unsigned int total_valid_node_count; /* valid node block count */
loff_t max_file_blocks; /* max block index of file */
@@ -3175,6 +3179,7 @@ void f2fs_clear_prefree_segments(struct f2fs_sb_info *sbi,
int f2fs_disable_cp_again(struct f2fs_sb_info *sbi, block_t unusable);
void f2fs_release_discard_addrs(struct f2fs_sb_info *sbi);
int f2fs_npages_for_summary_flush(struct f2fs_sb_info *sbi, bool for_ra);
+void allocate_segment_for_resize(struct f2fs_sb_info *sbi, int type);
void f2fs_allocate_new_segments(struct f2fs_sb_info *sbi);
int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range);
bool f2fs_exist_trim_candidates(struct f2fs_sb_info *sbi,
@@ -3318,6 +3323,7 @@ int f2fs_migrate_page(struct address_space *mapping, struct page *newpage,
int f2fs_gc(struct f2fs_sb_info *sbi, bool sync, bool background,
unsigned int segno);
void f2fs_build_gc_manager(struct f2fs_sb_info *sbi);
+int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count);

/*
* recovery.c
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index d05ac21..a37a0d4 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -3013,6 +3013,31 @@ static int f2fs_ioc_precache_extents(struct file *filp, unsigned long arg)
return f2fs_precache_extents(file_inode(filp));
}

+static int f2fs_ioc_resize_fs(struct file *filp, unsigned long arg)
+{
+ struct f2fs_sb_info *sbi = F2FS_I_SB(file_inode(filp));
+ __u64 block_count;
+ int ret;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (f2fs_readonly(sbi->sb))
+ return -EROFS;
+
+ if (copy_from_user(&block_count, (__u64 __user *)arg, sizeof(__u64)))
+ return -EFAULT;
+
+ ret = mnt_want_write_file(filp);
+ if (ret)
+ return ret;
+
+ ret = f2fs_resize_fs(sbi, block_count);
+ mnt_drop_write_file(filp);
+
+ return ret;
+}
+
long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
if (unlikely(f2fs_cp_error(F2FS_I_SB(file_inode(filp)))))
@@ -3069,6 +3094,8 @@ long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
return f2fs_ioc_set_pin_file(filp, arg);
case F2FS_IOC_PRECACHE_EXTENTS:
return f2fs_ioc_precache_extents(filp, arg);
+ case F2FS_IOC_RESIZE_FS:
+ return f2fs_ioc_resize_fs(filp, arg);
default:
return -ENOTTY;
}
@@ -3182,6 +3209,7 @@ long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case F2FS_IOC_GET_PIN_FILE:
case F2FS_IOC_SET_PIN_FILE:
case F2FS_IOC_PRECACHE_EXTENTS:
+ case F2FS_IOC_RESIZE_FS:
break;
default:
return -ENOIOCTLCMD;
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 963fb45..273ca08 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -311,10 +311,11 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
struct sit_info *sm = SIT_I(sbi);
struct victim_sel_policy p;
unsigned int secno, last_victim;
- unsigned int last_segment = MAIN_SEGS(sbi);
+ unsigned int last_segment;
unsigned int nsearched = 0;

mutex_lock(&dirty_i->seglist_lock);
+ last_segment = CUR_MAIN_SECS(sbi) * sbi->segs_per_sec;

p.alloc_mode = alloc_mode;
select_policy(sbi, gc_type, type, &p);
@@ -404,7 +405,8 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
sm->last_victim[p.gc_mode] = last_victim + 1;
else
sm->last_victim[p.gc_mode] = segno + 1;
- sm->last_victim[p.gc_mode] %= MAIN_SEGS(sbi);
+ sm->last_victim[p.gc_mode] %=
+ (CUR_MAIN_SECS(sbi) * sbi->segs_per_sec);
break;
}
}
@@ -1360,3 +1362,134 @@ void f2fs_build_gc_manager(struct f2fs_sb_info *sbi)
SIT_I(sbi)->last_victim[ALLOC_NEXT] =
GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
}
+
+static int free_segment_range(struct f2fs_sb_info *sbi, unsigned int start,
+ unsigned int end)
+{
+ int type;
+ unsigned int segno, next_inuse;
+ struct gc_inode_list gc_list = {
+ .ilist = LIST_HEAD_INIT(gc_list.ilist),
+ .iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
+ };
+ int err = 0;
+
+ /* Move out cursegs from the target range */
+ for (type = CURSEG_HOT_DATA; type < NR_CURSEG_TYPE; type++) {
+ segno = CURSEG_I(sbi, type)->segno;
+ if (segno >= start && segno <= end)
+ allocate_segment_for_resize(sbi, type);
+ }
+
+ /* do GC to move out valid blocks in the range */
+ mutex_lock(&sbi->gc_mutex);
+ for (segno = start; segno <= end; segno += sbi->segs_per_sec) {
+ do_garbage_collect(sbi, segno, &gc_list, FG_GC);
+ if (get_valid_blocks(sbi, segno, true)) {
+ err = -EAGAIN;
+ break;
+ }
+ }
+
+ mutex_unlock(&sbi->gc_mutex);
+ put_gc_inode(&gc_list);
+
+ if (err)
+ return err;
+
+ err = f2fs_sync_fs(sbi->sb, 1);
+ if (err)
+ return err;
+
+ next_inuse = find_next_inuse(FREE_I(sbi), end + 1, start);
+ if (next_inuse <= end) {
+ f2fs_msg(sbi->sb, KERN_ERR,
+ "segno %u should be free but still inuse!", next_inuse);
+ f2fs_bug_on(sbi, 1);
+ }
+ return err;
+}
+
+int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count)
+{
+ __u64 old_block_count, shrunk_blocks;
+ unsigned int secs;
+ int gc_mode, gc_type;
+ int err = 0;
+
+ old_block_count = le64_to_cpu(F2FS_RAW_SUPER(sbi)->block_count);
+ if (block_count > old_block_count)
+ return -EINVAL;
+
+ /* new fs size should align to section size */
+ if (block_count % BLKS_PER_SEC(sbi))
+ return -EINVAL;
+
+ if (block_count == old_block_count)
+ return 0;
+
+ shrunk_blocks = old_block_count - block_count;
+ secs = shrunk_blocks / BLKS_PER_SEC(sbi);
+ spin_lock(&sbi->stat_lock);
+ if (shrunk_blocks + valid_user_blocks(sbi) +
+ sbi->current_reserved_blocks + sbi->unusable_block_count +
+ F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
+ err = -ENOSPC;
+ else
+ sbi->user_block_count -= shrunk_blocks;
+ spin_unlock(&sbi->stat_lock);
+ if (err)
+ return err;
+
+ mutex_lock(&sbi->resize_mutex);
+ sbi->resizing = true;
+ mutex_lock(&DIRTY_I(sbi)->seglist_lock);
+ CUR_MAIN_SECS(sbi) = MAIN_SECS(sbi) - secs;
+ for (gc_mode = 0; gc_mode < MAX_GC_POLICY; gc_mode++)
+ if (SIT_I(sbi)->last_victim[gc_mode] >=
+ CUR_MAIN_SECS(sbi) * sbi->segs_per_sec)
+ SIT_I(sbi)->last_victim[gc_mode] = 0;
+ for (gc_type = BG_GC; gc_type <= FG_GC; gc_type++)
+ if (sbi->next_victim_seg[gc_type] >=
+ CUR_MAIN_SECS(sbi) * sbi->segs_per_sec)
+ sbi->next_victim_seg[gc_type] = NULL_SEGNO;
+ mutex_unlock(&DIRTY_I(sbi)->seglist_lock);
+
+ err = free_segment_range(sbi, CUR_MAIN_SECS(sbi) * sbi->segs_per_sec,
+ MAIN_SEGS(sbi) - 1);
+ if (err) {
+ CUR_MAIN_SECS(sbi) = MAIN_SECS(sbi);
+ sbi->user_block_count += shrunk_blocks;
+ goto out;
+ }
+
+ /* Update superblock */
+ F2FS_RAW_SUPER(sbi)->section_count = cpu_to_le32(CUR_MAIN_SECS(sbi));
+ F2FS_RAW_SUPER(sbi)->segment_count = cpu_to_le32(le32_to_cpu(
+ F2FS_RAW_SUPER(sbi)->segment_count) - secs * sbi->segs_per_sec);
+ F2FS_RAW_SUPER(sbi)->segment_count_main = cpu_to_le32(
+ CUR_MAIN_SECS(sbi) * sbi->segs_per_sec);
+ F2FS_RAW_SUPER(sbi)->block_count =
+ cpu_to_le64(old_block_count - shrunk_blocks);
+ mutex_lock(&sbi->gc_mutex);
+ err = f2fs_commit_super(sbi, false);
+ mutex_unlock(&sbi->gc_mutex);
+ if (err) {
+ CUR_MAIN_SECS(sbi) = MAIN_SECS(sbi);
+ sbi->user_block_count += shrunk_blocks;
+ goto out;
+ }
+
+ /* Update FS metadata */
+ SM_I(sbi)->segment_count -= secs * sbi->segs_per_sec;
+ MAIN_SECS(sbi) = CUR_MAIN_SECS(sbi);
+ MAIN_SEGS(sbi) = MAIN_SECS(sbi) * sbi->segs_per_sec;
+ F2FS_CKPT(sbi)->user_block_count = cpu_to_le64(sbi->user_block_count);
+ FREE_I(sbi)->free_sections -= secs;
+ FREE_I(sbi)->free_segments -= secs * sbi->segs_per_sec;
+
+out:
+ sbi->resizing = false;
+ mutex_unlock(&sbi->resize_mutex);
+ return err;
+}
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 07e9235..2857465 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2360,7 +2360,7 @@ static void get_new_segment(struct f2fs_sb_info *sbi,
{
struct free_segmap_info *free_i = FREE_I(sbi);
unsigned int segno, secno, zoneno;
- unsigned int total_zones = MAIN_SECS(sbi) / sbi->secs_per_zone;
+ unsigned int total_zones = CUR_MAIN_SECS(sbi) / sbi->secs_per_zone;
unsigned int hint = GET_SEC_FROM_SEG(sbi, *newseg);
unsigned int old_zoneno = GET_ZONE_FROM_SEG(sbi, *newseg);
unsigned int left_start = hint;
@@ -2377,12 +2377,13 @@ static void get_new_segment(struct f2fs_sb_info *sbi,
goto got_it;
}
find_other_zone:
- secno = find_next_zero_bit(free_i->free_secmap, MAIN_SECS(sbi), hint);
- if (secno >= MAIN_SECS(sbi)) {
+ secno = find_next_zero_bit(free_i->free_secmap, CUR_MAIN_SECS(sbi),
+ hint);
+ if (secno >= CUR_MAIN_SECS(sbi)) {
if (dir == ALLOC_RIGHT) {
secno = find_next_zero_bit(free_i->free_secmap,
- MAIN_SECS(sbi), 0);
- f2fs_bug_on(sbi, secno >= MAIN_SECS(sbi));
+ CUR_MAIN_SECS(sbi), 0);
+ f2fs_bug_on(sbi, secno >= CUR_MAIN_SECS(sbi));
} else {
go_left = 1;
left_start = hint - 1;
@@ -2397,8 +2398,8 @@ static void get_new_segment(struct f2fs_sb_info *sbi,
continue;
}
left_start = find_next_zero_bit(free_i->free_secmap,
- MAIN_SECS(sbi), 0);
- f2fs_bug_on(sbi, left_start >= MAIN_SECS(sbi));
+ CUR_MAIN_SECS(sbi), 0);
+ f2fs_bug_on(sbi, left_start >= CUR_MAIN_SECS(sbi));
break;
}
secno = left_start;
@@ -2651,6 +2652,29 @@ static void allocate_segment_by_default(struct f2fs_sb_info *sbi,
stat_inc_seg_type(sbi, curseg);
}

+void allocate_segment_for_resize(struct f2fs_sb_info *sbi, int type)
+{
+ struct curseg_info *curseg = CURSEG_I(sbi, type);
+ unsigned int old_segno = curseg->segno;
+
+ down_read(&SM_I(sbi)->curseg_lock);
+ mutex_lock(&curseg->curseg_mutex);
+ if (f2fs_need_SSR(sbi) && get_ssr_segment(sbi, type))
+ change_curseg(sbi, type);
+ else
+ new_curseg(sbi, type, true);
+
+ stat_inc_seg_type(sbi, curseg);
+ mutex_unlock(&curseg->curseg_mutex);
+ up_read(&SM_I(sbi)->curseg_lock);
+
+ if (get_valid_blocks(sbi, old_segno, false) == 0)
+ __set_test_and_free(sbi, old_segno);
+ f2fs_msg(sbi->sb, KERN_NOTICE,
+ "For resize: curseg of type %d: %u ==> %u",
+ type, old_segno, curseg->segno);
+}
+
void f2fs_allocate_new_segments(struct f2fs_sb_info *sbi)
{
struct curseg_info *curseg;
@@ -3774,7 +3798,7 @@ void f2fs_flush_sit_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
struct f2fs_journal *journal = curseg->journal;
struct sit_entry_set *ses, *tmp;
struct list_head *head = &SM_I(sbi)->sit_entry_set;
- bool to_journal = true;
+ bool to_journal = !sbi->resizing;
struct seg_entry *se;

down_write(&sit_i->sentry_lock);
@@ -3793,7 +3817,8 @@ void f2fs_flush_sit_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
* entries, remove all entries from journal and add and account
* them in sit entry set.
*/
- if (!__has_cursum_space(journal, sit_i->dirty_sentries, SIT_JOURNAL))
+ if (!__has_cursum_space(journal, sit_i->dirty_sentries, SIT_JOURNAL) ||
+ sbi->resizing)
remove_sits_in_journal(sbi);

/*
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 429007b..eaa9782 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -59,6 +59,7 @@

#define MAIN_SEGS(sbi) (SM_I(sbi)->main_segments)
#define MAIN_SECS(sbi) ((sbi)->total_sections)
+#define CUR_MAIN_SECS(sbi) ((sbi)->current_total_sections)

#define TOTAL_SEGS(sbi) \
(SM_I(sbi) ? SM_I(sbi)->segment_count : \
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 1f581f0..c6201f0 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2843,6 +2843,8 @@ static void init_sb_info(struct f2fs_sb_info *sbi)
sbi->segs_per_sec = le32_to_cpu(raw_super->segs_per_sec);
sbi->secs_per_zone = le32_to_cpu(raw_super->secs_per_zone);
sbi->total_sections = le32_to_cpu(raw_super->section_count);
+ sbi->current_total_sections = sbi->total_sections;
+ sbi->resizing = false;
sbi->total_node_count =
(le32_to_cpu(raw_super->segment_count_nat) / 2)
* sbi->blocks_per_seg * NAT_ENTRY_PER_BLOCK;
@@ -3296,6 +3298,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
mutex_init(&sbi->gc_mutex);
mutex_init(&sbi->writepages);
mutex_init(&sbi->cp_mutex);
+ mutex_init(&sbi->resize_mutex);
init_rwsem(&sbi->node_write);
init_rwsem(&sbi->node_change);

--
1.8.3.1