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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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3
include/linux/nfs_fs.h
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@@ -70,6 +70,7 @@ struct nfs_lock_context {
struct nfs4_state;
struct nfs_open_context {
struct nfs_lock_context lock_context;
fl_owner_t flock_owner;
struct dentry *dentry;
struct rpc_cred *cred;
struct nfs4_state *state;
@@ -357,7 +358,7 @@ extern void nfs_setsecurity(struct inode *inode, struct nfs_fattr *fattr,
extern struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx);
extern void put_nfs_open_context(struct nfs_open_context *ctx);
extern struct nfs_open_context *nfs_find_open_context(struct inode *inode, struct rpc_cred *cred, fmode_t mode);
extern struct nfs_open_context *alloc_nfs_open_context(struct dentry *dentry, fmode_t f_mode);
extern struct nfs_open_context *alloc_nfs_open_context(struct dentry *dentry, fmode_t f_mode, struct file *filp);
extern void nfs_inode_attach_open_context(struct nfs_open_context *ctx);
extern void nfs_file_set_open_context(struct file *filp, struct nfs_open_context *ctx);
extern void nfs_file_clear_open_context(struct file *flip);