0bf981278e
On *NIX platforms the statfs(2) system call returns a struct containing both the free blocks in the filesystem (Statfs_t.Bfree) and the free blocks available to the unprivileged or non-superuser (Statfs_t.Bavail). The `Bfree` and `Bavail` fields (with `Bfree >= Bavail`) will be set to different values on e.g. filesystems such as ext4 that reserve a certain percentage of the filesystem blocks which may only be allocated by admnistrative privileged processes. The calculations for the `Total` disk space need to subtract the difference between the `Bfree` and `Bavail` fields for it to correctly show the total available storage space available for unprivileged users. This implicitly fixes a bug where the `Used = Total - Free` calculation yielded different (and also incorrect) results for identical contents stored when only the sizes of the disks or backing volumes differed. (as can be witnessed in the `Used:` value displayed in the Minio browser) See: - https://wiki.archlinux.org/index.php/ext4#Reserved_blocks - http://man7.org/linux/man-pages/man2/statfs.2.html - https://man.openbsd.org/statfs - http://lingrok.org/xref/coreutils/src/df.c#893
42 lines
1.2 KiB
Go
42 lines
1.2 KiB
Go
// +build linux
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/*
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* Minio Cloud Storage, (C) 2015, 2016, 2017 Minio, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package disk
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import (
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"syscall"
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)
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// GetInfo returns total and free bytes available in a directory, e.g. `/`.
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func GetInfo(path string) (info Info, err error) {
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s := syscall.Statfs_t{}
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err = syscall.Statfs(path, &s)
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if err != nil {
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return Info{}, err
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}
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fsReservedBlocks := uint64(s.Bfree) - uint64(s.Bavail)
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info = Info{
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Total: uint64(s.Bsize) * (uint64(s.Blocks) - fsReservedBlocks),
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Free: uint64(s.Bsize) * uint64(s.Bavail),
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Files: uint64(s.Files),
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Ffree: uint64(s.Ffree),
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FSType: getFSType(int64(s.Type)),
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}
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return info, nil
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}
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