On Fri, Feb 10, 2023 at 03:48:09AM +0800, Kemeng Shi wrote: > We will add pa_free to s_mb_preallocated when new ext4_prealloc_space is > created. In ext4_mb_new_inode_pa, we will call ext4_mb_use_inode_pa > before adding pa_free to s_mb_preallocated. However, ext4_mb_use_inode_pa > will consume pa_free for block allocation which triggerred the creation > of ext4_prealloc_space. Add pa_free to s_mb_preallocated before > ext4_mb_use_inode_pa to correct calculation of s_mb_preallocated. > There is no such problem in ext4_mb_new_group_pa as pa_free of group pa > is consumed in ext4_mb_release_context instead of ext4_mb_use_group_pa. > > Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx> > --- > fs/ext4/mballoc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > index f24f80ecf318..2bffc93778d5 100644 > --- a/fs/ext4/mballoc.c > +++ b/fs/ext4/mballoc.c > @@ -4670,8 +4670,8 @@ ext4_mb_new_inode_pa(struct ext4_allocation_context *ac) > pa->pa_len, pa->pa_lstart); > trace_ext4_mb_new_inode_pa(ac, pa); > > - ext4_mb_use_inode_pa(ac, pa); > atomic_add(pa->pa_free, &sbi->s_mb_preallocated); > + ext4_mb_use_inode_pa(ac, pa); > > ei = EXT4_I(ac->ac_inode); > grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group); > -- > 2.30.0 > My understanding is that s_mb_preallocated is for all the blocks we ever preallocated and so we need to add 'original' pa_len instead of (pa_len - best_len). Hence, the patch looks correct to me. Feel free to add: Reviewed-by: Ojaswin Mujoo <ojaswin@xxxxxxxxxxxxx>
