【ubuntu】U盤許可權不足，只讀檔案系統
網上有很多，出現次數比較多的是這一種說法（但是不適用我的情況）：
轉自：http://blog.csdn.net/slj_win/article/details/50349976
在Windows下，U盤能夠正常地讀寫檔案（能複製貼上），但發現有個檔案打不開。然後在Ubuntu Linux下，U對U盤只能讀不能寫。提示：Read only system.
參考：https://bugs.launchpad.NET/ubuntu/+bug/228608
1，# tail -f /var/log/syslog 檢視檔案系統的動態資訊
May 19 21:31:28 controller kernel: [284792.451452] FAT-fs (sdb1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.
2，df -h 確定U盤的磁碟基本情況
/dev/sdb1 15G 7.8G 6.9G 54% /media/Hadoop/disk
3，執行命令：# fsck -C -a /dev/sdb1 進行自動修復...居然修復成功，而且打不開的檔案也完好無缺能夠打開了。感嘆linux的強大。
還有說重新掛載（不太懂掛載之類的，，確認指令不是錯的，照著來了一遍，，，不行）：
轉載自：http://blog.csdn.net/Lj_550566181/article/details/53924099
- 檢視U盤的掛載點
$df -h- 1
- 1
可以發現檔案系統的路徑為/dev/sdd4
- 然後使用命令即可
$ mount -o remount,rw /dev/sdd4 - 1
- 2
- 1
- 2
- 重新掛載完畢，問題解決
Linux下使用U盤時，在沒有解除安裝的情況下擅自拔出U盤後，U盤成為只讀檔案系統，說下修復的辦法。
環境：
OS
今天向U盤上拷了檔案後，沒有解除安裝就拔了U盤，再插上電腦，稍等片刻時，發現成為只讀檔案系統。嘗試使用sudo chmod a+w /U，顯示為只讀檔案系統。只好檢視列印的系統資訊
檢視系統列印資訊：
$
看到如下內容：
[29153.253989] usb 2-1.2.3.3: new full-speed USB device number 40 using ehci-pci [29153.423524] usb 2-1.2.3.3: not running at top speed; connect to a high speed hub [29153.431450] scsi20 : usb-storage 2-1.2.3.3:1.0 [29154.435792] scsi 20:0:0:0: Direct-Access Generic Flash Disk 8.07 PQ: 0 ANSI: 2 [29154.437255] sd 20:0:0:0: [sdb] 8212480 512-byte logical blocks: (4.20 GB/3.91 GiB) [29154.438207] sd 20:0:0:0: [sdb] Write Protect is off [29154.438214] sd 20:0:0:0: [sdb] Mode Sense: 03 00 00 00 [29154.438930] sd 20:0:0:0: [sdb] No Caching mode page present [29154.438934] sd 20:0:0:0: [sdb] Assuming drive cache: write through [29154.442123] sd 20:0:0:0: [sdb] No Caching mode page present [29154.442128] sd 20:0:0:0: [sdb] Assuming drive cache: write through [29154.473636] sdb: sdb1 [29154.476380] sd 20:0:0:0: [sdb] No Caching mode page present [29154.476388] sd 20:0:0:0: [sdb] Assuming drive cache: write through [29154.476404] sd 20:0:0:0: [sdb] Attached SCSI removable disk [29155.527602] FAT-fs (sdb1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck. [29167.626139] FAT-fs (sdb1): error, fat_get_cluster: invalid cluster chain (i_pos 2111071) [29167.626143] FAT-fs (sdb1): Filesystem has been set read-only [29167.626154] FAT-fs (sdb1): error, fat_get_cluster: invalid cluster chain (i_pos 2111071)
寫的很明白，被不適當的解除安裝造成有些資料錯誤，請使用fsck修復。
使用fsck修復：（sdb1是U盤的分割槽）
do fsck -fy /dev/sdb1
含義:肯定回答修復損壞的扇區，保險起見可以不加f與y。
修復後，正常解除安裝U盤，再插上U盤：
$
看到：
[29665.364058] usb 2-1.2.3.3: new full-speed USB device number 43 using ehci-pci
[29665.543688] usb 2-1.2.3.3: not running at top speed; connect to a high speed hub
[29665.551693] scsi23 : usb-storage 2-1.2.3.3:1.0
[29666.555758] scsi 23:0:0:0: Direct-Access Generic Flash Disk 8.07 PQ: 0 ANSI: 2
[29666.557362] sd 23:0:0:0: [sdb] 8212480 512-byte logical blocks: (4.20 GB/3.91 GiB)
[29666.557984] sd 23:0:0:0: [sdb] Write Protect is off
[29666.557987] sd 23:0:0:0: [sdb] Mode Sense: 03 00 00 00
[29666.558605] sd 23:0:0:0: [sdb] No Caching mode page present
[29666.558608] sd 23:0:0:0: [sdb] Assuming drive cache: write through
[29666.561606] sd 23:0:0:0: [sdb] No Caching mode page present
[29666.561609] sd 23:0:0:0: [sdb] Assuming drive cache: write through
[29666.893013] sdb: sdb1
[29666.895352] sd 23:0:0:0: [sdb] No Caching mode page present
[29666.895357] sd 23:0:0:0: [sdb] Assuming drive cache: write through
[29666.895361] sd 23:0:0:0: [sdb] Attached SCSI removable disk
開啟U盤，可以正常讀寫了。
可能都能有用，只是我只是太淺薄，加上各種第一次，各種萌新。。。就當做給以後自己儲存的一份資料了