CODEWITHSUNDEEP
linuxfuse
hillu
hillu

Reputation: 9611

How can I get more detailed filesystem information on FUSE filesystems?

On Linux systems, it is possible to identify "regular" filesystems using statfs(2) and inspecting the f_type. Constants for several filesystem types are mentioned in the statfs(2) manpage, such as

EXT4_SUPER_MAGIC      0xEF53
BTRFS_SUPER_MAGIC     0x9123683E
FUSE_SUPER_MAGIC      0x65735546
PROC_SUPER_MAGIC      0x9fa0
SYSFS_MAGIC           0x62656572

(It turns out that those are actually defined in linux/magic.h.)

I would like to be able to distinguish well-known remote filesystems (such as sshfs) from well-known local filesystems (such as the ntfs-3g). Is there any way to find out more about FUSE-based filesystems, such as a name at this point?

Upvotes: 2

Views: 1185

Answers (1)

Appleman1234
Appleman1234

Reputation: 16086

As per some old IBM fuse documentation and the implementation of both sshfs and ntfs-3g setting f_type in the statfs implementation of each of the these filesystems appears to be ignored.

I believe using this method would result in a value of 0x65735546 based on the initialization of the value here.

A mechanism to get filesystem information in userspace is /proc/mounts or /proc/<pid>/mountinfo as documented here. This has the 9th field as filesystem type which has FUSE subtypes (if they were specified as a mount option and supported by the kernel) as type.subtype. E.g fuse.sshfs or fuse.ntfs-3g.

To access the same information in kernelspace , you can use lookup_mnt with the path, to get a pointer to a vfsmount struct, from that you can access the superblock and then the subtype. Where struct vfsmount *mnt and the subtype is mnt->mnt_sb->s_subtype.

Upvotes: 1

Related Questions