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linux-stable/fs/nfs/nfs4_fs.h
David Howells 65f27f3844 WorkStruct: Pass the work_struct pointer instead of context data 
Pass the work_struct pointer to the work function rather than context data.
The work function can use container_of() to work out the data.

For the cases where the container of the work_struct may go away the moment the
pending bit is cleared, it is made possible to defer the release of the
structure by deferring the clearing of the pending bit.

To make this work, an extra flag is introduced into the management side of the
work_struct.  This governs auto-release of the structure upon execution.

Ordinarily, the work queue executor would release the work_struct for further
scheduling or deallocation by clearing the pending bit prior to jumping to the
work function.  This means that, unless the driver makes some guarantee itself
that the work_struct won't go away, the work function may not access anything
else in the work_struct or its container lest they be deallocated..  This is a
problem if the auxiliary data is taken away (as done by the last patch).

However, if the pending bit is *not* cleared before jumping to the work
function, then the work function *may* access the work_struct and its container
with no problems.  But then the work function must itself release the
work_struct by calling work_release().

In most cases, automatic release is fine, so this is the default.  Special
initiators exist for the non-auto-release case (ending in _NAR).


Signed-Off-By: David Howells <dhowells@redhat.com>
2006-11-22 14:55:48 +00:00

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/*
* linux/fs/nfs/nfs4_fs.h
*
* Copyright (C) 2005 Trond Myklebust
*
* NFSv4-specific filesystem definitions and declarations
*/
#ifndef __LINUX_FS_NFS_NFS4_FS_H
#define __LINUX_FS_NFS_NFS4_FS_H
#ifdef CONFIG_NFS_V4
struct idmap;
/*
* In a seqid-mutating op, this macro controls which error return
* values trigger incrementation of the seqid.
*
* from rfc 3010:
* The client MUST monotonically increment the sequence number for the
* CLOSE, LOCK, LOCKU, OPEN, OPEN_CONFIRM, and OPEN_DOWNGRADE
* operations. This is true even in the event that the previous
* operation that used the sequence number received an error. The only
* exception to this rule is if the previous operation received one of
* the following errors: NFSERR_STALE_CLIENTID, NFSERR_STALE_STATEID,
* NFSERR_BAD_STATEID, NFSERR_BAD_SEQID, NFSERR_BADXDR,
* NFSERR_RESOURCE, NFSERR_NOFILEHANDLE.
*
*/
#define seqid_mutating_err(err) \
(((err) != NFSERR_STALE_CLIENTID) && \
((err) != NFSERR_STALE_STATEID) && \
((err) != NFSERR_BAD_STATEID) && \
((err) != NFSERR_BAD_SEQID) && \
((err) != NFSERR_BAD_XDR) && \
((err) != NFSERR_RESOURCE) && \
((err) != NFSERR_NOFILEHANDLE))
enum nfs4_client_state {
NFS4CLNT_STATE_RECOVER = 0,
NFS4CLNT_LEASE_EXPIRED,
};
/*
* struct rpc_sequence ensures that RPC calls are sent in the exact
* order that they appear on the list.
*/
struct rpc_sequence {
struct rpc_wait_queue wait; /* RPC call delay queue */
spinlock_t lock; /* Protects the list */
struct list_head list; /* Defines sequence of RPC calls */
};
#define NFS_SEQID_CONFIRMED 1
struct nfs_seqid_counter {
struct rpc_sequence *sequence;
int flags;
u32 counter;
};
struct nfs_seqid {
struct nfs_seqid_counter *sequence;
struct list_head list;
};
static inline void nfs_confirm_seqid(struct nfs_seqid_counter *seqid, int status)
{
if (seqid_mutating_err(-status))
seqid->flags |= NFS_SEQID_CONFIRMED;
}
/*
* NFS4 state_owners and lock_owners are simply labels for ordered
* sequences of RPC calls. Their sole purpose is to provide once-only
* semantics by allowing the server to identify replayed requests.
*/
struct nfs4_state_owner {
spinlock_t so_lock;
struct list_head so_list; /* per-clientid list of state_owners */
struct nfs_client *so_client;
u32 so_id; /* 32-bit identifier, unique */
atomic_t so_count;
struct rpc_cred *so_cred; /* Associated cred */
struct list_head so_states;
struct list_head so_delegations;
struct nfs_seqid_counter so_seqid;
struct rpc_sequence so_sequence;
};
/*
* struct nfs4_state maintains the client-side state for a given
* (state_owner,inode) tuple (OPEN) or state_owner (LOCK).
*
* OPEN:
* In order to know when to OPEN_DOWNGRADE or CLOSE the state on the server,
* we need to know how many files are open for reading or writing on a
* given inode. This information too is stored here.
*
* LOCK: one nfs4_state (LOCK) to hold the lock stateid nfs4_state(OPEN)
*/
struct nfs4_lock_state {
struct list_head ls_locks; /* Other lock stateids */
struct nfs4_state * ls_state; /* Pointer to open state */
fl_owner_t ls_owner; /* POSIX lock owner */
#define NFS_LOCK_INITIALIZED 1
int ls_flags;
struct nfs_seqid_counter ls_seqid;
u32 ls_id;
nfs4_stateid ls_stateid;
atomic_t ls_count;
};
/* bits for nfs4_state->flags */
enum {
LK_STATE_IN_USE,
NFS_DELEGATED_STATE,
};
struct nfs4_state {
struct list_head open_states; /* List of states for the same state_owner */
struct list_head inode_states; /* List of states for the same inode */
struct list_head lock_states; /* List of subservient lock stateids */
struct nfs4_state_owner *owner; /* Pointer to the open owner */
struct inode *inode; /* Pointer to the inode */
unsigned long flags; /* Do we hold any locks? */
spinlock_t state_lock; /* Protects the lock_states list */
nfs4_stateid stateid;
unsigned int n_rdonly;
unsigned int n_wronly;
unsigned int n_rdwr;
int state; /* State on the server (R,W, or RW) */
atomic_t count;
};
struct nfs4_exception {
long timeout;
int retry;
};
struct nfs4_state_recovery_ops {
int (*recover_open)(struct nfs4_state_owner *, struct nfs4_state *);
int (*recover_lock)(struct nfs4_state *, struct file_lock *);
};
extern struct dentry_operations nfs4_dentry_operations;
extern struct inode_operations nfs4_dir_inode_operations;
/* inode.c */
extern ssize_t nfs4_getxattr(struct dentry *, const char *, void *, size_t);
extern int nfs4_setxattr(struct dentry *, const char *, const void *, size_t, int);
extern ssize_t nfs4_listxattr(struct dentry *, char *, size_t);
/* nfs4proc.c */
extern int nfs4_map_errors(int err);
extern int nfs4_proc_setclientid(struct nfs_client *, u32, unsigned short, struct rpc_cred *);
extern int nfs4_proc_setclientid_confirm(struct nfs_client *, struct rpc_cred *);
extern int nfs4_proc_async_renew(struct nfs_client *, struct rpc_cred *);
extern int nfs4_proc_renew(struct nfs_client *, struct rpc_cred *);
extern int nfs4_do_close(struct inode *inode, struct nfs4_state *state);
extern struct dentry *nfs4_atomic_open(struct inode *, struct dentry *, struct nameidata *);
extern int nfs4_open_revalidate(struct inode *, struct dentry *, int, struct nameidata *);
extern int nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *fhandle);
extern int nfs4_proc_fs_locations(struct inode *dir, struct dentry *dentry,
struct nfs4_fs_locations *fs_locations, struct page *page);
extern struct nfs4_state_recovery_ops nfs4_reboot_recovery_ops;
extern struct nfs4_state_recovery_ops nfs4_network_partition_recovery_ops;
extern const u32 nfs4_fattr_bitmap[2];
extern const u32 nfs4_statfs_bitmap[2];
extern const u32 nfs4_pathconf_bitmap[2];
extern const u32 nfs4_fsinfo_bitmap[2];
extern const u32 nfs4_fs_locations_bitmap[2];
/* nfs4renewd.c */
extern void nfs4_schedule_state_renewal(struct nfs_client *);
extern void nfs4_renewd_prepare_shutdown(struct nfs_server *);
extern void nfs4_kill_renewd(struct nfs_client *);
extern void nfs4_renew_state(struct work_struct *);
/* nfs4state.c */
struct rpc_cred *nfs4_get_renew_cred(struct nfs_client *clp);
extern u32 nfs4_alloc_lockowner_id(struct nfs_client *);
extern struct nfs4_state_owner * nfs4_get_state_owner(struct nfs_server *, struct rpc_cred *);
extern void nfs4_put_state_owner(struct nfs4_state_owner *);
extern void nfs4_drop_state_owner(struct nfs4_state_owner *);
extern struct nfs4_state * nfs4_get_open_state(struct inode *, struct nfs4_state_owner *);
extern void nfs4_put_open_state(struct nfs4_state *);
extern void nfs4_close_state(struct nfs4_state *, mode_t);
extern void nfs4_state_set_mode_locked(struct nfs4_state *, mode_t);
extern void nfs4_schedule_state_recovery(struct nfs_client *);
extern void nfs4_put_lock_state(struct nfs4_lock_state *lsp);
extern int nfs4_set_lock_state(struct nfs4_state *state, struct file_lock *fl);
extern void nfs4_copy_stateid(nfs4_stateid *, struct nfs4_state *, fl_owner_t);
extern struct nfs_seqid *nfs_alloc_seqid(struct nfs_seqid_counter *counter);
extern int nfs_wait_on_sequence(struct nfs_seqid *seqid, struct rpc_task *task);
extern void nfs_increment_open_seqid(int status, struct nfs_seqid *seqid);
extern void nfs_increment_lock_seqid(int status, struct nfs_seqid *seqid);
extern void nfs_free_seqid(struct nfs_seqid *seqid);
extern const nfs4_stateid zero_stateid;
/* nfs4xdr.c */
extern __be32 *nfs4_decode_dirent(__be32 *p, struct nfs_entry *entry, int plus);
extern struct rpc_procinfo nfs4_procedures[];
struct nfs4_mount_data;
/* callback_xdr.c */
extern struct svc_version nfs4_callback_version1;
#else
#define nfs4_close_state(a, b) do { } while (0)
#endif /* CONFIG_NFS_V4 */
#endif /* __LINUX_FS_NFS_NFS4_FS.H */
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