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nfs: disable leases over NFS 

As Peter Staubach says elsewhere
(http://marc.info/?l=linux-kernel&m=118113649526444&w=2):

> The problem is that some file system such as NFSv2 and NFSv3 do
> not have sufficient support to be able to support leases correctly.
> In particular for these two file systems, there is no over the wire
> protocol support.
>
> Currently, these two file systems fail the fcntl(F_SETLEASE) call
> accidentally, due to a reference counting difference.  These file
> systems should fail more consciously, with a proper error to
> indicate that the call is invalid for them.

Define an nfs setlease method that just returns -EINVAL.

If someone can demonstrate a real need, perhaps we could reenable
them in the presence of the "nolock" mount option.

Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Cc: Peter Staubach <staubach@redhat.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
J. Bruce Fields 2007-06-08 15:23:34 -04:00
parent 60446067ba
commit 370f6599e8
1 changed files with 12 additions and 0 deletions
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12
fs/nfs/file.c
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@ -53,6 +53,7 @@ static int nfs_fsync(struct file *, struct dentry *dentry, int datasync);
static int nfs_check_flags(int flags);
static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl);
static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl);
static int nfs_setlease(struct file *file, long arg, struct file_lock **fl);
const struct file_operations nfs_file_operations = {
.llseek = nfs_file_llseek,
@ -69,6 +70,7 @@ const struct file_operations nfs_file_operations = {
.flock = nfs_flock,
.splice_read = nfs_file_splice_read,
.check_flags = nfs_check_flags,
.setlease = nfs_setlease,
};
const struct inode_operations nfs_file_inode_operations = {
@ -558,3 +560,13 @@ static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
return do_unlk(filp, cmd, fl);
return do_setlk(filp, cmd, fl);
}
static int nfs_setlease(struct file *file, long arg, struct file_lock **fl)
{
/*
* There is no protocol support for leases, so we have no way
* to implement them correctly in the face of opens by other
* clients.
*/
return -EINVAL;
}