There's a slight problem (other than HCH not liking it) with this

approach of passing the open file in iattr:  for special files, the

struct file pointer makes no sense to the filesystem, since it is always

opened by the generic functions.
This wasn't a problem with ftruncate(), because that one only works on

regular files, but fchmod/fchown/futimes will work on special files as

well, and the filesystem interpreting file->private_data could cause

nasty bugs. 
So I think the correct solution (which was suggested by Trond and

others) is to define an f_op->fsetattr() method, which interested

filesystems can define.
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So what do you think where the inodes come from for syscalls like fchmod? Out

of struct file, of course. But your f_op->getattr and f_op->setattr patches

are meant for passing struct file down to filesystems anyway, so that 
That's nothing but a replacement for ATTR_FILE and iattr->ia_file. Except by

removing the ATTR_FILE flag, LSMs will no longer get that information for

distinguishing file descriptor operations from other operations.
AppArmor needs to know when notify_change is called on a file descriptor, but

it doesn't care about the file descriptor itself. So any way of passing along

that information will be fine.
Thanks,

Andreas

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For special files, f_op->fsetattr will be NULL, since

init_special_inode() will set up i_fop that way.
So the filesystem's fsetattr() will only be called for regular files

and/or directories, depending on how it sets up i_fop.
With the ia_file thing, the filesystem would receive the struct file

pointer in all cases.  So the posted patch would break AFS and FUSE,

because they unconditionally use ia_file if available and don't check

the file type.  They could check the file type, but still the interface
Ah, so if we kept ATTR_FILE and got rid of iattr_file, would that be OK

for AppArmor? 
Thanks,

Miklos
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No problem, yes.
Thanks,

Andreas

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yeah that does sound like the way to go, thank Miklos
regards

john