ufs: fix the logics for tail relocation
* original hysteresis loop got broken by typo back in 2002; now
it never switches out of OPTTIME state. Fixed.
* critical levels for switching from OPTTIME to OPTSPACE and back
ought to be calculated once, at mount time.
* we should use mul_u64_u32_div() for those calculations, now that
->s_dsize is 64bit.
* to quote Kirk McKusick (in 1995 FreeBSD commit message):
The threshold for switching from time-space and space-time is too small
when minfree is 5%...so make it stay at space in this case.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/ufs/super.c b/fs/ufs/super.c
index 34656c7..f211b66 100644
--- a/fs/ufs/super.c
+++ b/fs/ufs/super.c
@@ -1211,6 +1211,15 @@ static int ufs_fill_super(struct super_block *sb, void *data, int silent)
uspi->s_root_blocks = mul_u64_u32_div(uspi->s_dsize,
uspi->s_minfree, 100);
+ if (uspi->s_minfree <= 5) {
+ uspi->s_time_to_space = ~0ULL;
+ uspi->s_space_to_time = 0;
+ usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTSPACE);
+ } else {
+ uspi->s_time_to_space = (uspi->s_root_blocks / 2) + 1;
+ uspi->s_space_to_time = mul_u64_u32_div(uspi->s_dsize,
+ uspi->s_minfree - 2, 100) - 1;
+ }
/*
* Compute another frequently used values
