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linux/fs/nfs/nfs4_fs.h
Trond Myklebust 6f2e64d3e1 NFSv4: Make the NFS state model work with the nosharedcache mount option 
Consider the case where the user has mounted the remote filesystem
server:/foo on the two local directories /bar and /baz using the
nosharedcache mount option. The files /bar/file and /baz/file are
represented by different inodes in the local namespace, but refer to the
same file /foo/file on the server.
Consider the case where a process opens both /bar/file and /baz/file, then
closes /bar/file: because the nfs4_state is not shared between /bar/file
and /baz/file, the kernel will see that the nfs4_state for /bar/file is no
longer referenced, so it will send off a CLOSE rpc call. Unless the
open_owners differ, then that CLOSE call will invalidate the open state on
/baz/file too.

Conclusion: we cannot share open state owners between two different
non-shared mount instances of the same filesystem.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:48 -04:00

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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;
}
struct nfs_unique_id {
struct rb_node rb_node;
__u64 id;
};
/*
* 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 {
struct nfs_unique_id so_owner_id;
struct nfs_client *so_client;
struct nfs_server *so_server;
struct rb_node so_client_node;
struct rpc_cred *so_cred; /* Associated cred */
spinlock_t so_lock;
atomic_t so_count;
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;
struct nfs_unique_id ls_id;
nfs4_stateid ls_stateid;
atomic_t ls_count;
};
/* bits for nfs4_state->flags */
enum {
LK_STATE_IN_USE,
NFS_DELEGATED_STATE, /* Current stateid is delegation */
NFS_O_RDONLY_STATE, /* OPEN stateid has read-only state */
NFS_O_WRONLY_STATE, /* OPEN stateid has write-only state */
NFS_O_RDWR_STATE, /* OPEN stateid has read/write 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 */
seqlock_t seqlock; /* Protects the stateid/open_stateid */
nfs4_stateid stateid; /* Current stateid: may be delegation */
nfs4_stateid open_stateid; /* OPEN stateid */
/* The following 3 fields are protected by owner->so_lock */
unsigned int n_rdonly; /* Number of read-only references */
unsigned int n_wronly; /* Number of write-only references */
unsigned int n_rdwr; /* Number of read/write references */
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 const 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 path *path, 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 qstr *name,
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 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 path *, 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, c) do { } while (0)
#endif /* CONFIG_NFS_V4 */
#endif /* __LINUX_FS_NFS_NFS4_FS.H */
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