在已啟動的電腦上執行 fsck 會在根檔案系統上產生錯誤。為了解決這個問題，我從 LiveCD 啟動 - 但 LiveCD 實例上的 fsck 根本沒有發現任何錯誤。我還嘗試運行與啟動系統相同的二進位檔案 - 具有 0 個錯誤的相同結果。
這裡發生了什麼事？如何修復報告的錯誤？ （見下文）
該機器是無頭Ubuntu 14.04，LiveCD來自Ubuntu 14.04桌面版。
當我跑步時：
fsck -v -n /dev/mapper/lvm-root -f
響應是：
fsck from util-linux 2.20.1
e2fsck 1.42.9 (4-Feb-2014)
Warning! /dev/mapper/lvm-root is mounted.
Warning: skipping journal recovery because doing a read-only filesystem check.
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
Block bitmap differences: -(24598720--24598781) +(42616517--42616542) -(47432723--47432748) +(49925184--49925211) +(49925312--49925373)
Fix? no
Free blocks count wrong for group #750 (22700, counted=22638).
Fix? no
Free blocks count wrong for group #1300 (13150, counted=13176).
Fix? no
Free blocks count wrong for group #1447 (24124, counted=24098).
Fix? no
Free blocks count wrong for group #1523 (32016, counted=32106).
Fix? no
Free blocks count wrong (30301182, counted=30319341).
Fix? no
Inode bitmap differences: -11927698 +11927700
Fix? no
Free inodes count wrong (15762199, counted=15762204).
Fix? no
/dev/mapper/lvm-root: ********** WARNING: Filesystem still has errors **********
130281 inodes used (0.82%, out of 15892480)
1113 non-contiguous files (0.9%)
112 non-contiguous directories (0.1%)
# of inodes with ind/dind/tind blocks: 0/0/0
Extent depth histogram: 121424/640
33268738 blocks used (52.33%, out of 63569920)
0 bad blocks
3 large files
101907 regular files
19700 directories
2 character device files
0 block device files
2 fifos
22 links
8624 symbolic links (8166 fast symbolic links)
32 sockets
------------
130289 files
為了解決這個問題，我從 Ubuntu 14.04 LiveCD 啟動並執行相同的命令：
root@ubuntu:~# fsck -n -v /dev/mapper/lvm-root -f
fsck from util-linux 2.20.1
e2fsck 1.42.9 (4-Feb-2014)
Warning! /dev/mapper/lvm-root is mounted.
Warning: skipping journal recovery because doing a read-only filesystem check.
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
130281 inodes used (0.82%, out of 15892480)
1114 non-contiguous files (0.9%)
112 non-contiguous directories (0.1%)
# of inodes with ind/dind/tind blocks: 0/0/0
Extent depth histogram: 121429/640
33268738 blocks used (52.33%, out of 63569920)
0 bad blocks
3 large files
101908 regular files
19704 directories
2 character device files
0 block device files
2 fifos
22 links
8625 symbolic links (8167 fast symbolic links)
31 sockets
------------
130294 files
沒有錯誤，我覺得很奇怪。所以我嘗試掛載根分區，並手動運行位於 /sbin/fsck 下的 fsck：
root@ubuntu:~# /mnt/sbin/fsck -n -v /dev/mapper/lvm-root -f
fsck from util-linux 2.20.1
e2fsck 1.42.9 (4-Feb-2014)
Warning! /dev/mapper/lvm-root is mounted.
Warning: skipping journal recovery because doing a read-only filesystem check.
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
130281 inodes used (0.82%, out of 15892480)
1114 non-contiguous files (0.9%)
112 non-contiguous directories (0.1%)
# of inodes with ind/dind/tind blocks: 0/0/0
Extent depth histogram: 121429/640
33268738 blocks used (52.33%, out of 63569920)
0 bad blocks
3 large files
101908 regular files
19704 directories
2 character device files
0 block device files
2 fifos
22 links
8625 symbolic links (8167 fast symbolic links)
31 sockets
------------
130294 files
答案1
在已安裝的檔案系統上執行 fsck 將顯示與此時關閉系統電源時發生的錯誤相同的錯誤；磁碟上的狀態不一致，因為更新已緩衝在記憶體中但尚未寫入磁碟。因此不要這樣做！
僅在未掛載的檔案系統上執行 fsck。即使在只讀安裝的檔案系統上，如果 fsck 修復了問題而核心不知道，也可能會出現問題。