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问题[fat32](unix)

Martin Hope
BMWW
Asked: 2018-05-01 11:51:44 +0800 CST
  • 5

格式化我的 EFI 分区时出现此错误：

Not enough clusters for a 32 bit FAT!"

我的磁盘使用 4096 扇区大小。

#mkfs.fat -v -F 32 -S 4096 /dev/sde1

mkfs.fat 4.1 (2017-01-24)
WARNING: Not enough clusters for a 32 bit FAT!
/dev/sde1 has 255 heads and 63 sectors per track,
hidden sectors 0x4000;
logical sector size is 4096,
using 0xf8 media descriptor, with 67584 sectors;
drive number 0x80;
filesystem has 2 32-bit FATs and 8 sectors per cluster.
FAT size is 16 sectors, and provides 8440 clusters.
There are 32 reserved sectors.
Volume ID is 05deb9f7, no volume label.

我的磁盘分区：

gdisk -l /dev/sde
GPT fdisk (gdisk) version 1.0.1

Partition table scan:
   MBR: protective
   BSD: not present
   APM: not present
   GPT: present

Found valid GPT with protective MBR; using GPT.
Disk /dev/sde: 244190646 sectors, 931.5 GiB
Logical sector size: 4096 bytes
Disk identifier (GUID): D0BA102E-86C5-4379-B314-9534F873C377
Partition table holds up to 128 entries
First usable sector is 6, last usable sector is 244190640
Partitions will be aligned on 256-sector boundaries
Total free space is 244123051 sectors (931.3 GiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048           69631   264.0 MiB   0700  EFI_FAT32

fsck.fat给出以下内容：

#fsck.fat -v /dev/sde1
fsck.fat 4.1 (2017-01-24)
Checking we can access the last sector of the filesystem
Warning: Filesystem is FAT32 according to fat_length and fat32_length fields,
  but has only 8440 clusters, less than the required minimum of 65525.
  This may lead to problems on some systems.
Boot sector contents:
System ID "mkfs.fat"
Media byte 0xf8 (hard disk)
      4096 bytes per logical sector
     32768 bytes per cluster
        32 reserved sectors
First FAT starts at byte 131072 (sector 32)
         2 FATs, 32 bit entries
     65536 bytes per FAT (= 16 sectors)
Root directory start at cluster 2 (arbitrary size)
Data area starts at byte 262144 (sector 64)
      8440 data clusters (276561920 bytes)
63 sectors/track, 255 heads
     16384 hidden sectors
     67584 sectors total
Checking for unused clusters.
Checking free cluster summary.
/dev/sde1: 1 files, 1/8440 clusters
uefi fat32
Martin Hope
airbornemihir
Asked: 2018-04-17 09:22:22 +0800 CST
  • 0

我正在尝试研究 FAT32 的内部结构，为此我正在尝试创建一个 FAT32 映像，挂载它并在命令行上执行一些文件操作。根据这里的问题，我知道没有办法使用 sudo 来安装图像。我仍然想知道为什么我最终需要 sudo 才能在挂载点内进行文件操作。下面是一个小的 bash 脚本，它演示了哪些有效，哪些无效。有人可以告诉我如何在没有 root 的情况下执行此操作吗？

DISK=/tmp/disk1.raw
MOUNTPOINT=/tmp/mount1
SIZE=512M
rm -f $DISK
rm -rf $MOUNTPOINT

# create disk image
qemu-img create -f raw $DISK $SIZE
# format disk image
mkfs.fat -v -F 32 $DISK
# make mountpoint
mkdir -p $MOUNTPOINT

# can't be helped
sudo mount -o loop -t msdos $DISK $MOUNTPOINT
# should work but doesn't
mkdir -p $MOUNTPOINT/tmp/
# actually works
sudo mkdir -p $MOUNTPOINT/tmp/
# should work but doesn't
dd of=$MOUNTPOINT/tmp/ticket2.txt if=/dev/zero bs=512 count=9
# actually works
sudo dd of=$MOUNTPOINT/tmp/ticket2.txt if=/dev/zero bs=512 count=9

ls -lR $MOUNTPOINT
sudo umount $MOUNTPOINT
fat32