2007-06-08 22:14:59

by J.Bruce Fields

[permalink] [raw]
Subject: [PATCH 5/5] nfs: disable leases over NFS

From: J. Bruce Fields <[email protected]>

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" <[email protected]>
Cc: Peter Staubach <[email protected]>
---
fs/nfs/file.c | 7 +++++++
1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 9eb8eb4..467671b 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -51,6 +51,7 @@ 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,
@@ -67,6 +68,7 @@ const struct file_operations nfs_file_operations = {
.flock = nfs_flock,
.sendfile = nfs_file_sendfile,
.check_flags = nfs_check_flags,
+ .setlease = nfs_setlease,
};

const struct inode_operations nfs_file_inode_operations = {
@@ -555,3 +557,8 @@ 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)
+{
+ return -EINVAL;
+}
--
1.5.2


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