In linux file system, when file system error happens, the first choice is to do an fsck of the unmounted file system.<\/p>\n
Usually,<\/p>\n
fsck -y \/dev\/sdxx<\/p>\n
at boot time should be able to fix everything, if the FS has not been severely damaged.<\/p>\n
Occasionally, as reported as<\/p>\n
Debian bug list #478546 at<\/p>\n
http:\/\/groups.google.com\/group\/linux.debian.bugs.dist\/browse_thread\/thread\/dc48335d2ca42b66<\/p>\n
fsck returns error like: And, what ever you repeat fsck, or use e2fsprogs won’t help about this.<\/p>\n Here I explain the cause of this and prresent a solution as following:<\/p>\n [REASON]<\/p>\n In the messed up FS, an orphaned inode with ZERO data length was labelled as a directory, and was restored into lost+found\/ on the alleged file system.<\/p>\n However, for a valid directory entry, it cannot be ZERO length.\u00a0 It has to have at least two entries namely ‘.’ linking to itself and ‘..’ linking to its parent directory.\u00a0 However, since this directory entry has zero length, fsck failed creating ‘..’ thus resulted the error<\/p>\n “ and resulted a fail of the fsck.<\/p>\n [SOLUTION]<\/p>\n When fsck is done, mount the FS.\u00a0 Then cd the lost+found\/ directory:<\/p>\n If you do ‘ls -al’, you will see a directory with zero length named #<the affected inode>, like here #122068977.<\/p>\n It usually has a weird owner and group number.<\/p>\n You then do the following: This will make it look normal.<\/p>\n Then Note you cannot do<\/p>\n still here since ‘..’ does not exist yet.<\/p>\n Then if you do again, the length of the directory # At this point, you can cd off the mounted filesystem, and umount it:<\/p>\n and fsck it: It then will result: This will save you from the risk of running a FS with errors or fully copy the file system elsewhere to recreate it.<\/p>\n","protected":false},"excerpt":{"rendered":" In linux file system, when file system error happens, the first choice is to do an fsck of the unmounted file system. Usually, fsck -y \/dev\/sdxx at boot time should be able to fix everything, if the FS has not been severely damaged. Occasionally, as reported as Debian bug list #478546 at http:\/\/groups.google.com\/group\/linux.debian.bugs.dist\/browse_thread\/thread\/dc48335d2ca42b66 fsck returns […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[21,3],"tags":[],"class_list":["post-70","post","type-post","status-publish","format-standard","hentry","category-computer-tips","category-mri-technical-support","post-blog"],"_links":{"self":[{"href":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/index.php?rest_route=\/wp\/v2\/posts\/70","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=70"}],"version-history":[{"count":0,"href":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/index.php?rest_route=\/wp\/v2\/posts\/70\/revisions"}],"wp:attachment":[{"href":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=70"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=70"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=70"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n
\nfsck 1.40.8 (13-Mar-2008)
\ne2fsck 1.40.8 (13-Mar-2008)
\nBackup contains a file system with errors, check forced.
\nPass 1: Checking inodes, blocks, and sizes
\nPass 2: Checking directory structure
\nPass 3: Checking directory connectivity
\n'..' in \/lost+found\/#122068977 (122068977) is <The NULL inode> (0),
\nshould be \/lost+found (11).
\nFix? yes<\/code>
\n
\nCouldn't fix parent of inode 122068977: Couldn't find parent directory entry<\/code>
\n
\nPass 4: Checking reference counts
\nPass 5: Checking group summary information<\/code>
\n
\nBackup: ********** WARNING: Filesystem still has errors **********<\/code>
\n
\nBackup: 14398872\/122077184 files (1.4% non-contiguous),
\n188901088\/244137600 blocks<\/code><\/p>\nCouldn't fix parent of inode 122068977: Couldn't find parent directory entry\"<\/code><\/p>\nmount #<your mount point>
\ncd #<your mount point>
\ncd lost+found<\/code><\/p>\n
\n
\nchown root:root #<the affected inode>
\nchmod 755 #<the affected inode><\/code><\/p>\n
\n
\ncd #<the affected inode>
\ntouch test
\nrm test
\ncd #<your mount point><\/code><\/p>\ncd ..<\/code><\/p>\n
\nls -al<\/code><\/p>\n<the affected inode> is no longer 0, but the default minimum length of your file system, say 4096, 8192, or 16384, etc.<\/code><\/p>\ncd ~
\numount #<your mount point><\/code><\/p>\n
\nfsck -y \/dev\/<your device><\/code><\/p>\n
\n
\nfsck 1.40.2 (12-Jul-2007)
\ne2fsck 1.40.2 (12-Jul-2007)
\n<your FS> was not cleanly unmounted, check forced.
\nPass 1: Checking inodes, blocks, and sizes
\nPass 2: Checking directory structure
\nMissing '.' in directory inode <bad inode number>.
\nFix? yes<\/code>
\n
\nSetting filetype for entry '.' in ... (<bad inode number>) to 2.
\nMissing '..' in directory inode <bad inode number>.
\nFix? yes<\/code>
\n
\nSetting filetype for entry '..' in ... (<bad inode number>) to 2.
\nPass 3: Checking directory connectivity
\n'..' in \/lost+found\/<bad inode number> (<bad inode number>) is
\n(0), should be \/lost+found (11).
\nFix? yes<\/code>
\n
\nPass 4: Checking reference counts
\nInode 2 ref count is 6, should be 7. Fix? yes<\/code>
\n
\nInode 11 ref count is 4, should be 3. Fix? yes<\/code>
\n
\nInode <bad inode number> ref count is 1, should be 2. Fix? yes<\/code>
\n
\nPass 5: Checking group summary information<\/code>
\n
\n<your FS>: ***** FILE SYSTEM WAS MODIFIED *****
\n<your FS>: 1882918\/91193344 files (0.3% non-contiguous), 111803861\/182339584 blocks<\/code><\/p>\n