f2fs: fix to reserve space for IO align feature
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
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index b7287b7..af98abb 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -289,6 +289,46 @@ static inline void limit_reserve_root(struct f2fs_sb_info *sbi)
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)
@@ -3736,6 +3776,10 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
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 =