From 77e9ce327d9b607cd6e57c0f4524a654dc59c4b1 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sat, 17 Jun 2017 15:44:06 -0400
Subject: [PATCH] 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>
---
fs/ufs/balloc.c | 22 ++++++----------------
fs/ufs/super.c | 9 +++++++++
fs/ufs/ufs_fs.h | 2 ++
3 files changed, 17 insertions(+), 16 deletions(-)
diff --git a/fs/ufs/balloc.c b/fs/ufs/balloc.c
index 0315fea1d589e..f80be4c5df9d1 100644
--- a/fs/ufs/balloc.c
+++ b/fs/ufs/balloc.c
@@ -455,24 +455,14 @@ u64 ufs_new_fragments(struct inode *inode, void *p, u64 fragment,
/*
* allocate new block and move data
*/
- switch (fs32_to_cpu(sb, usb1->fs_optim)) {
- case UFS_OPTSPACE:
+ if (fs32_to_cpu(sb, usb1->fs_optim) == UFS_OPTSPACE) {
request = newcount;
- if (uspi->s_minfree < 5 || uspi->cs_total.cs_nffree
- > uspi->s_dsize * uspi->s_minfree / (2 * 100))
- break;
- usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTTIME);
- break;
- default:
- usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTTIME);
-
- case UFS_OPTTIME:
+ if (uspi->cs_total.cs_nffree < uspi->s_space_to_time)
+ usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTTIME);
+ } else {
request = uspi->s_fpb;
- if (uspi->cs_total.cs_nffree < uspi->s_dsize *
- (uspi->s_minfree - 2) / 100)
- break;
- usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTTIME);
- break;
+ if (uspi->cs_total.cs_nffree > uspi->s_time_to_space)
+ usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTSPACE);
}
result = ufs_alloc_fragments (inode, cgno, goal, request, err);
if (result) {
diff --git a/fs/ufs/super.c b/fs/ufs/super.c
index 34656c7a8e227..f211b662dd92a 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
diff --git a/fs/ufs/ufs_fs.h b/fs/ufs/ufs_fs.h
index 823d55a375860..150eef6f12331 100644
--- a/fs/ufs/ufs_fs.h
+++ b/fs/ufs/ufs_fs.h
@@ -792,6 +792,8 @@ struct ufs_sb_private_info {
__s32 fs_magic; /* filesystem magic */
unsigned int s_dirblksize;
__u64 s_root_blocks;
+ __u64 s_time_to_space;
+ __u64 s_space_to_time;
};
/*