[PATCH 5.4 292/320] f2fs: fix to reserve space for IO align feature

Greg Kroah-Hartman
2022-01-25T03:23:57Z

From: Chao Yu <chao@kernel.org>

commit 300a842937fbcfb5a189cea9ba15374fdb0b5c6b upstream.

https://bugzilla.kernel.org/show_bug.cgi?id=204137

With below script, we will hit panic during new segment allocation:

DISK=bingo.img
MOUNT_DIR=/mnt/f2fs

dd if=/dev/zero of=$DISK bs=1M count=105
mkfs.f2fe -a 1 -o 19 -t 1 -z 1 -f -q $DISK

mount -t f2fs $DISK $MOUNT_DIR -o "noinline_dentry,flush_merge,noextent_cache,mode=lfs,io_bits=7,fsync_mode=strict"

for (( i = 0; i < 4096; i++ )); do
name=`head /dev/urandom | tr -dc A-Za-z0-9 | head -c 10`
mkdir $MOUNT_DIR/$name
done

umount $MOUNT_DIR
rm $DISK

---
fs/f2fs/f2fs.h | 11 +++++++++++
fs/f2fs/segment.h | 3 ++-
fs/f2fs/super.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
fs/f2fs/sysfs.c | 4 +++-
4 files changed, 60 insertions(+), 2 deletions(-)

--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -931,6 +931,7 @@ struct f2fs_sm_info {
unsigned int segment_count; /* total # of segments */
unsigned int main_segments; /* # of segments in main area */
unsigned int reserved_segments; /* # of reserved segments */
+ unsigned int additional_reserved_segments;/* reserved segs for IO align feature */
unsigned int ovp_segments; /* # of overprovision segments */

/* a threshold to reclaim prefree segments */
@@ -1800,6 +1801,11 @@ static inline int inc_valid_block_count(

if (!__allow_reserved_blocks(sbi, inode, true))
avail_user_block_count -= F2FS_OPTION(sbi).root_reserved_blocks;
+
+ if (F2FS_IO_ALIGNED(sbi))
+ avail_user_block_count -= sbi->blocks_per_seg *
+ SM_I(sbi)->additional_reserved_segments;
+
if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
if (avail_user_block_count > sbi->unusable_block_count)
avail_user_block_count -= sbi->unusable_block_count;
@@ -2045,6 +2051,11 @@ static inline int inc_valid_node_count(s

if (!__allow_reserved_blocks(sbi, inode, false))
valid_block_count += F2FS_OPTION(sbi).root_reserved_blocks;
+
+ if (F2FS_IO_ALIGNED(sbi))
+ valid_block_count += sbi->blocks_per_seg *
+ SM_I(sbi)->additional_reserved_segments;
+
user_block_count = sbi->user_block_count;
if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED)))
user_block_count -= sbi->unusable_block_count;
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -508,7 +508,8 @@ static inline unsigned int free_segments

static inline int reserved_segments(struct f2fs_sb_info *sbi)
{
- return SM_I(sbi)->reserved_segments;
+ return SM_I(sbi)->reserved_segments +
+ SM_I(sbi)->additional_reserved_segments;
}

static inline unsigned int free_sections(struct f2fs_sb_info *sbi)
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -277,6 +277,46 @@ static inline void limit_reserve_root(st
F2FS_OPTION(sbi).s_resgid));
}

+static inline int adjust_reserved_segment(struct f2fs_sb_info *sbi)
+{
+ unsigned int sec_blks = sbi->blocks_per_seg * sbi->segs_per_sec;
+ unsigned int avg_vblocks;
+ unsigned int wanted_reserved_segments;
+ block_t avail_user_block_count;
+
+ if (!F2FS_IO_ALIGNED(sbi))
+ return 0;
+
+ /* average valid block count in section in worst case */
+ avg_vblocks = sec_blks / F2FS_IO_SIZE(sbi);
+
+ /*
+ * we need enough free space when migrating one section in worst case
+ */
+ wanted_reserved_segments = (F2FS_IO_SIZE(sbi) / avg_vblocks) *
+ reserved_segments(sbi);
+ wanted_reserved_segments -= reserved_segments(sbi);
+
+ avail_user_block_count = sbi->user_block_count -
+ sbi->current_reserved_blocks -
+ F2FS_OPTION(sbi).root_reserved_blocks;
+
+ if (wanted_reserved_segments * sbi->blocks_per_seg >
+ avail_user_block_count) {
+ f2fs_err(sbi, "IO align feature can't grab additional reserved segment: %u, available segments: %u",
+ wanted_reserved_segments,
+ avail_user_block_count >> sbi->log_blocks_per_seg);
+ return -ENOSPC;
+ }
+
+ SM_I(sbi)->additional_reserved_segments = wanted_reserved_segments;
+
+ f2fs_info(sbi, "IO align feature needs additional reserved segment: %u",
+ wanted_reserved_segments);
+
+ return 0;
+}
+
static inline void adjust_unusable_cap_perc(struct f2fs_sb_info *sbi)
{
if (!F2FS_OPTION(sbi).unusable_cap_perc)
@@ -3450,6 +3490,10 @@ try_onemore:
goto free_nm;
}

+ err = adjust_reserved_segment(sbi);
+ if (err)
+ goto free_nm;
+
/* For write statistics */
if (sb->s_bdev->bd_part)
sbi->sectors_written_start =
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -262,7 +262,9 @@ out:
if (a->struct_type == RESERVED_BLOCKS) {
spin_lock(&sbi->stat_lock);
if (t > (unsigned long)(sbi->user_block_count -
- F2FS_OPTION(sbi).root_reserved_blocks)) {
+ F2FS_OPTION(sbi).root_reserved_blocks -
+ sbi->blocks_per_seg *
+ SM_I(sbi)->additional_reserved_segments)) {
spin_unlock(&sbi->stat_lock);
return -EINVAL;
}