Linux EXT4文件系统TF卡空间容量显示和计算

本文主要是介绍Linux EXT4文件系统TF卡空间容量显示和计算，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

以32GB的EXT4文件系统为例进行计算。

驱动信息

usb 1-1.3: new full-speed USB device number 4 using ci_hdrc
scsi 0:0:0:0: Direct-Access     Generic  STORAGE DEVICE   0819 PQ: 0 ANSI: 6
sd 0:0:0:0: [sda] 62566400 512-byte logical blocks: (32.0 GB/29.8 GiB)
sd 0:0:0:0: [sda] Write Protect is off
sd 0:0:0:0: [sda] Write cache: disabled, read cache: enabled, doesn't support DPO or FUAsda: sda1
sd 0:0:0:0: [sda] Attached SCSI removable disk

fdisk查看信息

Disk /dev/sda: 32.0 GB, 32033996800 bytes
64 heads, 32 sectors/track, 30550 cylinders, total 62566400 sectors
Units = sectors of 1 * 512 = 512 bytesDevice Boot      Start         End      Blocks  Id System
/dev/sda1            2048    62566399    31282176  83 Linux

SD卡容量32GB，实际可存储容量为32033996800 bytes=31283200KB (62566400 * 512 = 29.833984375GB)

文件系统容量为31282176 KB，start 2048前面存储的是分区信息，占用2048*512=1024KB

挂载

/dev/sda1 on /mnt/sda1 type ext4 (rw,relatime,data=ordered)

容量df

Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/sda1             30659500     45232  29033776   0% /mnt/sda1

容量单位是1k，所以就是数字后面加k;

容量大小为30659500 KB （纯文件数据块容量）

使用大小为45232 KB（实际文件数据块173K + 还有什么占用数据块？）

空闲大小为29033776 KB（剩余数据块，不包含预留的空间）

隐藏大小为30659500 - 29079008 =1580492 KB （就是文件系统预留空间）

dumpe2fs信息

数据块总容量：7820544 * 4K = 31282176

使用大小：667756K（文件系统信息数据 + 实际文件数据块大小）

空闲容量：7653605 * 4K = 30614420

预留容量：391027 * 4K = 1564108

root@www:~# /mnt/emmc/dumpe2fs /dev/sda1 -h
dumpe2fs 1.44.5 (15-Dec-2018)
Filesystem volume name:   <none>
Last mounted on:          /mnt/sda1
Filesystem UUID:          d200bbcf-7fa9-40a7-b69a-8891ed917744
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery extent 64bit flex_bg sparse_super large_file huge_file dir_nlink extra_isize
Filesystem flags:         unsigned_directory_hash 
Default mount options:    user_xattr acl
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              1957888
Block count:              7820544
Reserved block count:     391027
Free blocks:              7653605
Free inodes:              1957877
First block:              0
Block size:               4096
Fragment size:            4096
Group descriptor size:    64
Reserved GDT blocks:      1024
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         8192
Inode blocks per group:   512
Flex block group size:    16
Filesystem created:       Mon Jan 21 10:26:05 2019
Last mount time:          Thu Jan  3 18:25:12 2019
Last write time:          Thu Jan  3 18:25:12 2019
Mount count:              1
Maximum mount count:      -1
Last checked:             Mon Jan 21 10:26:05 2019
Check interval:           0 (<none>)
Lifetime writes:          612 MB
Reserved blocks uid:      0 (user unknown)
Reserved blocks gid:      0 (group unknown)
First inode:              11
Inode size:	          256
Required extra isize:     32
Desired extra isize:      32
Journal inode:            8
Default directory hash:   half_md4
Directory Hash Seed:      1a43adc3-ca82-4a24-bb2a-8195f1c7aabb
Journal backup:           inode blocks
Journal features:         journal_64bit
Journal size:             128M
Journal length:           32768
Journal sequence:         0x00000002
Journal start:            1