[dspillett]

1. This depends on the filesystem. For ext2/3/4 (and many others) there is a reference count maintained in the first inode of the file. You can usually see this count in the output of "ls -l", between the perms and ownership columns. If someone goes wrong and the count isn't decremented properly (due to a system crash while the inode is being updated) or is otherwise corrupt, the space allocated to the object may never be released when it is deleted because the count will never reach zero. This is one of the checks/fixes fsck.ext* does when run. If the count is somehow too low the content could be deallocated too early, resulting in corruption (the remaining link(s) ending up pointing to the wrong data when the inode is eventually refused). Again fsck can detect this, but only if it is not too late and things are already mislinked or some of the space relocated.

2. A dangling soft link points to nothing valid. If you try to access it in a way that would normally give you the object it points to there will be a not found error. If a new object of the destination name appears the link will start to work again but give the new content. If relative links are moved around out of step with what they point to this can cause significant confusion. This is not filesystem level corruption that fsck can/will check for.