| Message ID | 20190530004906.261170-3-drosen@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | F2FS Checkpointing without GC, related fixes | expand |
On 2019/5/30 8:49, Daniel Rosenberg wrote: > On a remount, you can currently set root reserved if it was not > previously set. This can cause an underflow if reserved has been set to > a very high value, since then root reserved + current reserved could be > greater than user_block_count. inc_valid_block_count later subtracts out > these values from user_block_count, causing an underflow. > > Signed-off-by: Daniel Rosenberg <drosen@google.com> Reviewed-by: Chao Yu <yuchao0@huawei.com> Thanks,
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 912e2619d581b..359fd68509d16 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -213,7 +213,8 @@ void f2fs_msg(struct super_block *sb, const char *level, const char *fmt, ...) static inline void limit_reserve_root(struct f2fs_sb_info *sbi) { - block_t limit = (sbi->user_block_count << 1) / 1000; + block_t limit = min((sbi->user_block_count << 1) / 1000, + sbi->user_block_count - sbi->reserved_blocks); /* limit is 0.2% */ if (test_opt(sbi, RESERVE_ROOT) &&
On a remount, you can currently set root reserved if it was not previously set. This can cause an underflow if reserved has been set to a very high value, since then root reserved + current reserved could be greater than user_block_count. inc_valid_block_count later subtracts out these values from user_block_count, causing an underflow. Signed-off-by: Daniel Rosenberg <drosen@google.com> --- fs/f2fs/super.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)