1. File systems: ext2, ext3, reiserfs, xfs, etc.
2. Scope: When the file system prompts for FSCK, it has not been executed or FSCK execution is complete.
[Symptoms]
1. Unable to MOUNT the partition;
2. A large number of files and directories are lost, and a /LOST+FOUND folder is generated under the root directory, containing a large number of #XXXXX files.