E2BIG Returned from read(2) operations when the kernel's request
is too large for the provided buffer and the request was
FUSE_SETXATTR.
EINVAL Returned from write(2) if validation of the reply failed.
Not all mistakes in replies will be caught by this
validation. However, basic mistakes, such as short
replies or an incorrect unique value, are detected.
EIO Returned from read(2) operations when the kernel's request
is too large for the provided buffer.
Note: There are various ways in which incorrect use of
these interfaces can cause operations on the provided
filesystem's files and directories to fail with EIO.
Among the possible incorrect uses are:
* changing mode & S_IFMT for an inode that has previously
been reported to the kernel; or
* giving replies to the kernel that are shorter than what
the kernel expected.
ENODEV Returned from read(2) and write(2) if the FUSE filesystem
was unmounted.
EPERM Returned from operations on a /dev/fuse file descriptor
that has not been mounted.
