On 2019/5/30 8:49, Daniel Rosenberg wrote:
> Fixes possible underflows when dealing with unusable blocks.
>
> Signed-off-by: Daniel Rosenberg <drosen@xxxxxxxxxx>
> ---
> fs/f2fs/f2fs.h | 15 ++++++++++-----
> 1 file changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 9b3d9977cd1ef..a39cc4ffeb4b1 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1769,8 +1769,12 @@ static inline int inc_valid_block_count(struct f2fs_sb_info *sbi,
>
> if (!__allow_reserved_blocks(sbi, inode, true))
> avail_user_block_count -= F2FS_OPTION(sbi).root_reserved_blocks;
> - if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED)))
> - avail_user_block_count -= sbi->unusable_block_count;
> + if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
> + if (avail_user_block_count > sbi->unusable_block_count)
> + avail_user_block_count = 0;
avail_user_block_count -= sbi->unusable_block_count;
> + else
> + avail_user_block_count -= sbi->unusable_block_count;
avail_user_block_count = 0;
Thanks,
> + }
> if (unlikely(sbi->total_valid_block_count > avail_user_block_count)) {
> diff = sbi->total_valid_block_count - avail_user_block_count;
> if (diff > *count)
> @@ -1970,7 +1974,7 @@ static inline int inc_valid_node_count(struct f2fs_sb_info *sbi,
> struct inode *inode, bool is_inode)
> {
> block_t valid_block_count;
> - unsigned int valid_node_count;
> + unsigned int valid_node_count, user_block_count;
> int err;
>
> if (is_inode) {
> @@ -1997,10 +2001,11 @@ static inline int inc_valid_node_count(struct f2fs_sb_info *sbi,
>
> if (!__allow_reserved_blocks(sbi, inode, false))
> valid_block_count += F2FS_OPTION(sbi).root_reserved_blocks;
> + user_block_count = sbi->user_block_count;
> if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED)))
> - valid_block_count += sbi->unusable_block_count;
> + user_block_count -= sbi->unusable_block_count;
>
> - if (unlikely(valid_block_count > sbi->user_block_count)) {
> + if (unlikely(valid_block_count > user_block_count)) {
> spin_unlock(&sbi->stat_lock);
> goto enospc;
> }
>
