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NFSv4: add flock_owner to open context

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An open file description (struct file) in a given process can be
associated with two different lock owners.

It can have a Posix lock owner which will be different in each process
that has a fd on the file.
It can have a Flock owner which will be the same in all processes.

When searching for a lock stateid to use, we need to consider both of these
owners

So add a new "flock_owner" to the "nfs_open_context" (of which there
is one for each open file description).

This flock_owner does not need to be reference-counted as there is a
1-1 relation between 'struct file' and nfs open contexts,
and it will never be part of a list of contexts.  So there is no need
for a 'flock_context' - just the owner is enough.

The io_count included in the (Posix) lock_context provides no
guarantee that all read-aheads that could use the state have
completed, so not supporting it for flock locks in not a serious
problem.  Synchronization between flock and read-ahead can be added
later if needed.

When creating an open_context for a non-openning create call, we don't have
a 'struct file' to pass in, so the lock context gets initialized with
a NULL owner, but this will never be used.

The flock_owner is not used at all in this patch, that will come later.

Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This commit is contained in:
NeilBrown
2016-10-13 15:26:47 +11:00
committed by Trond Myklebust
parent b184b5c38e
commit 532d4def2f
5 changed files with 12 additions and 8 deletions
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6
fs/nfs/dir.c
View File

@@ -1467,9 +1467,9 @@ static fmode_t flags_to_mode(int flags)
return res;
}
static struct nfs_open_context *create_nfs_open_context(struct dentry *dentry, int open_flags)
static struct nfs_open_context *create_nfs_open_context(struct dentry *dentry, int open_flags, struct file *filp)
{
return alloc_nfs_open_context(dentry, flags_to_mode(open_flags));
return alloc_nfs_open_context(dentry, flags_to_mode(open_flags), filp);
}
static int do_open(struct inode *inode, struct file *filp)
@@ -1554,7 +1554,7 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
return finish_no_open(file, dentry);
}
ctx = create_nfs_open_context(dentry, open_flags);
ctx = create_nfs_open_context(dentry, open_flags, file);
err = PTR_ERR(ctx);
if (IS_ERR(ctx))
goto out;