2021-02-20 09:37:28

by Chao Yu

[permalink] [raw]
Subject: [PATCH 1/2] f2fs: fix to allow migrating fully valid segment

F2FS_IOC_FLUSH_DEVICE/F2FS_IOC_RESIZE_FS needs to migrate all blocks of
target segment to other place, no matter the segment has partially or fully
valid blocks.

However, after commit 803e74be04b3 ("f2fs: stop GC when the victim becomes
fully valid"), we may skip migration due to target segment is fully valid,
result in failing the ioctl interface, fix this.

Fixes: 803e74be04b3 ("f2fs: stop GC when the victim becomes fully valid")
Signed-off-by: Chao Yu <[email protected]>
---
fs/f2fs/f2fs.h | 2 +-
fs/f2fs/file.c | 9 +++++----
fs/f2fs/gc.c | 21 ++++++++++++---------
fs/f2fs/segment.c | 2 +-
fs/f2fs/super.c | 2 +-
5 files changed, 20 insertions(+), 16 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 2860003a09ed..ed7807103c8e 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3548,7 +3548,7 @@ void f2fs_destroy_post_read_wq(struct f2fs_sb_info *sbi);
int f2fs_start_gc_thread(struct f2fs_sb_info *sbi);
void f2fs_stop_gc_thread(struct f2fs_sb_info *sbi);
block_t f2fs_start_bidx_of_node(unsigned int node_ofs, struct inode *inode);
-int f2fs_gc(struct f2fs_sb_info *sbi, bool sync, bool background,
+int f2fs_gc(struct f2fs_sb_info *sbi, bool sync, bool background, bool force,
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);
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 8e53f8898688..e1e6b2ad5c54 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1656,7 +1656,7 @@ static int expand_inode_data(struct inode *inode, loff_t offset,
if (has_not_enough_free_secs(sbi, 0,
GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi)))) {
down_write(&sbi->gc_lock);
- err = f2fs_gc(sbi, true, false, NULL_SEGNO);
+ err = f2fs_gc(sbi, true, false, false, NULL_SEGNO);
if (err && err != -ENODATA && err != -EAGAIN)
goto out_err;
}
@@ -2487,7 +2487,7 @@ static int f2fs_ioc_gc(struct file *filp, unsigned long arg)
down_write(&sbi->gc_lock);
}

- ret = f2fs_gc(sbi, sync, true, NULL_SEGNO);
+ ret = f2fs_gc(sbi, sync, true, false, NULL_SEGNO);
out:
mnt_drop_write_file(filp);
return ret;
@@ -2523,7 +2523,8 @@ static int __f2fs_ioc_gc_range(struct file *filp, struct f2fs_gc_range *range)
down_write(&sbi->gc_lock);
}

- ret = f2fs_gc(sbi, range->sync, true, GET_SEGNO(sbi, range->start));
+ ret = f2fs_gc(sbi, range->sync, true, false,
+ GET_SEGNO(sbi, range->start));
if (ret) {
if (ret == -EBUSY)
ret = -EAGAIN;
@@ -2976,7 +2977,7 @@ static int f2fs_ioc_flush_device(struct file *filp, unsigned long arg)
sm->last_victim[GC_CB] = end_segno + 1;
sm->last_victim[GC_GREEDY] = end_segno + 1;
sm->last_victim[ALLOC_NEXT] = end_segno + 1;
- ret = f2fs_gc(sbi, true, true, start_segno);
+ ret = f2fs_gc(sbi, true, true, true, start_segno);
if (ret == -EAGAIN)
ret = 0;
else if (ret < 0)
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 39330ad3c44e..b3af76340026 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -112,7 +112,7 @@ static int gc_thread_func(void *data)
sync_mode = F2FS_OPTION(sbi).bggc_mode == BGGC_MODE_SYNC;

/* if return value is not zero, no victim was selected */
- if (f2fs_gc(sbi, sync_mode, true, NULL_SEGNO))
+ if (f2fs_gc(sbi, sync_mode, true, false, NULL_SEGNO))
wait_ms = gc_th->no_gc_sleep_time;

trace_f2fs_background_gc(sbi->sb, wait_ms,
@@ -1354,7 +1354,8 @@ static int move_data_page(struct inode *inode, block_t bidx, int gc_type,
* the victim data block is ignored.
*/
static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
- struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
+ struct gc_inode_list *gc_list, unsigned int segno, int gc_type,
+ bool force_migrate)
{
struct super_block *sb = sbi->sb;
struct f2fs_summary *entry;
@@ -1383,8 +1384,8 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
* race condition along with SSR block allocation.
*/
if ((gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) ||
- get_valid_blocks(sbi, segno, true) ==
- BLKS_PER_SEC(sbi))
+ (!force_migrate && get_valid_blocks(sbi, segno, true) ==
+ BLKS_PER_SEC(sbi)))
return submitted;

if (check_valid_map(sbi, segno, off) == 0)
@@ -1519,7 +1520,8 @@ static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,

static int do_garbage_collect(struct f2fs_sb_info *sbi,
unsigned int start_segno,
- struct gc_inode_list *gc_list, int gc_type)
+ struct gc_inode_list *gc_list, int gc_type,
+ bool force_migrate)
{
struct page *sum_page;
struct f2fs_summary_block *sum;
@@ -1606,7 +1608,8 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
gc_type);
else
submitted += gc_data_segment(sbi, sum->entries, gc_list,
- segno, gc_type);
+ segno, gc_type,
+ force_migrate);

stat_inc_seg_count(sbi, type, gc_type);
migrated++;
@@ -1634,7 +1637,7 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
}

int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
- bool background, unsigned int segno)
+ bool background, bool force, unsigned int segno)
{
int gc_type = sync ? FG_GC : BG_GC;
int sec_freed = 0, seg_freed = 0, total_freed = 0;
@@ -1696,7 +1699,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
if (ret)
goto stop;

- seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type);
+ seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type, force);
if (gc_type == FG_GC &&
seg_freed == f2fs_usable_segs_in_sec(sbi, segno))
sec_freed++;
@@ -1835,7 +1838,7 @@ static int free_segment_range(struct f2fs_sb_info *sbi,
.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
};

- do_garbage_collect(sbi, segno, &gc_list, FG_GC);
+ do_garbage_collect(sbi, segno, &gc_list, FG_GC, true);
put_gc_inode(&gc_list);

if (!gc_only && get_valid_blocks(sbi, segno, true)) {
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 440634dfaa56..2190910c68b0 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -504,7 +504,7 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need)
*/
if (has_not_enough_free_secs(sbi, 0, 0)) {
down_write(&sbi->gc_lock);
- f2fs_gc(sbi, false, false, NULL_SEGNO);
+ f2fs_gc(sbi, false, false, false, NULL_SEGNO);
}
}

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 30d5abef4361..78d9e54bc4f7 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1869,7 +1869,7 @@ static int f2fs_disable_checkpoint(struct f2fs_sb_info *sbi)

while (!f2fs_time_over(sbi, DISABLE_TIME)) {
down_write(&sbi->gc_lock);
- err = f2fs_gc(sbi, true, false, NULL_SEGNO);
+ err = f2fs_gc(sbi, true, false, false, NULL_SEGNO);
if (err == -ENODATA) {
err = 0;
break;
--
2.29.2


2021-02-20 09:39:45

by Chao Yu

[permalink] [raw]
Subject: [PATCH 2/2] f2fs: fix panic during f2fs_resize_fs()

f2fs_resize_fs() hangs in below callstack with testcase:
- mkfs 16GB image & mount image
- dd 8GB fileA
- dd 8GB fileB
- sync
- rm fileA
- sync
- resize filesystem to 8GB

kernel BUG at segment.c:2484!
Call Trace:
allocate_segment_by_default+0x92/0xf0 [f2fs]
f2fs_allocate_data_block+0x44b/0x7e0 [f2fs]
do_write_page+0x5a/0x110 [f2fs]
f2fs_outplace_write_data+0x55/0x100 [f2fs]
f2fs_do_write_data_page+0x392/0x850 [f2fs]
move_data_page+0x233/0x320 [f2fs]
do_garbage_collect+0x14d9/0x1660 [f2fs]
free_segment_range+0x1f7/0x310 [f2fs]
f2fs_resize_fs+0x118/0x330 [f2fs]
__f2fs_ioctl+0x487/0x3680 [f2fs]
__x64_sys_ioctl+0x8e/0xd0
do_syscall_64+0x33/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xa9

The root cause is we forgot to check that whether we have enough space
in resized filesystem to store all valid blocks in before-resizing
filesystem, then allocator will run out-of-space during block migration
in free_segment_range().

Fixes: b4b10061ef98 ("f2fs: refactor resize_fs to avoid meta updates in progress")
Signed-off-by: Chao Yu <[email protected]>
---
fs/f2fs/gc.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index b3af76340026..86ba8ed0b8a7 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1977,7 +1977,20 @@ int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count)

/* stop CP to protect MAIN_SEC in free_segment_range */
f2fs_lock_op(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;
+ spin_unlock(&sbi->stat_lock);
+
+ if (err)
+ goto out_unlock;
+
err = free_segment_range(sbi, secs, true);
+
+out_unlock:
f2fs_unlock_op(sbi);
up_write(&sbi->gc_lock);
if (err)
--
2.29.2