Re: [RFD] What error should FS return when I/O failure occurs?

[Valdis . Kletnieks]

On Mon, 16 May 2005 14:04:04 EDT, fs said:

> The point is(from the user's perspective, not FS developer's):
> If you open a file with O_RDWR, and sys_open returns success,
> next, call sys_write, but returns EROFS? The two return values are
> paradox/self-contradictory.

You'd be better off pointing out that 'man 2 write' lists the errors that
might be returned as:  EBAF, EINVAL, EFAULT, EFBIG, EPIPE, EAGAIN, EINTR,
ENOSPC, and EIO.

Does the POSIX spec allow write() to return -EROFS?

What happens if you're writing to an NFS-mounted file system, and the remote
system remounts the disk R/O?  What is reported in that case?

> The purpose of this RFD, is to get the community to understand,
> all I/O related syscalls should return VFS error, not FS error.

All fine and good, until you hit a case like ext3 where reporting
the FS error code will better explain the *real* problem than forcing
it to fit into one of the provided VFS errors.

> User mode app should not care about the FS they are using. 
> So, the community should define the ONLY VFS error first.

I think that's been done, and the VFS behavior is "if the FS reports
an error we pass it up to userspace".

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