Check if a folder is on a shared or local disk?

Question

How can I check if some folder in Linux is on a shared disk or a local disk?

Answer 1

You can tell whether a folder is on a local disk by looking up the filesystem type. The first part of the answer is to find what filesystem contains the folder. To do that you need to find the filesystem using the st_dev field of the stat information for the folder. (You can also do this by checking the folder path, but you then have to check every path element for symbolic links).

You can then cross-reference the st_dev field with the mount table in /proc/mounts using getmntent_r(). There's an example of that in a previous answer. The mnt_type field will give you the text of the filesystem type, and you can compare the string with a list of network filesystems.

You can tell more information about FUSE filesystems by looking at the mnt_fsname field, but there are a lot of FUSE filesystems. You may want to treat them all as network storage. You'll have to make your own call about cluster filesystems such as GFS.