From 77e9ce327d9b607cd6e57c0f4524a654dc59c4b1 Mon Sep 17 00:00:00 2001 From: Al Viro 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 --- 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; }; /*