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linux/fs/nfs/delegation.h
Benjamin Coddington a9b8d90f87 NFSv4: fairly test all delegations on a SEQ4_ revocation
When the client is required to use TEST_STATEID to discover which
delegation(s) have been revoked, it may continually test delegations at the
head of the list if the server continues to be unsatisfied and send
SEQ4_STATUS_RECALLABLE_STATE_REVOKED.  For a large number of delegations
this behavior is prone to live-lock because the client may never be able to
test and free revoked state at the end of the list since the
SEQ4_STATUS_RECALLABLE_STATE_REVOKED will cause us to flag delegations at
the head of the list to be tested.  This problem is further exacerbated by
the state manager's willingness to be scheduled out on a busy system while
testing the list of delegations.

Keep a generation counter for each attempt to test all delegations, and
skip delegations that have already been tested in the current pass.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Torkil Svensgaard <torkil@drcmr.dk>
Tested-by: Ruben Vestergaard <rubenv@drcmr.dk>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2023-11-01 15:15:52 -04:00

93 lines
3.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* linux/fs/nfs/delegation.h
*
* Copyright (c) Trond Myklebust
*
* Definitions pertaining to NFS delegated files
*/
#ifndef FS_NFS_DELEGATION_H
#define FS_NFS_DELEGATION_H
#if IS_ENABLED(CONFIG_NFS_V4)
/*
* NFSv4 delegation
*/
struct nfs_delegation {
struct list_head super_list;
const struct cred *cred;
struct inode *inode;
nfs4_stateid stateid;
fmode_t type;
unsigned long pagemod_limit;
__u64 change_attr;
unsigned long test_gen;
unsigned long flags;
refcount_t refcount;
spinlock_t lock;
struct rcu_head rcu;
};
enum {
NFS_DELEGATION_NEED_RECLAIM = 0,
NFS_DELEGATION_RETURN,
NFS_DELEGATION_RETURN_IF_CLOSED,
NFS_DELEGATION_REFERENCED,
NFS_DELEGATION_RETURNING,
NFS_DELEGATION_REVOKED,
NFS_DELEGATION_TEST_EXPIRED,
NFS_DELEGATION_INODE_FREEING,
NFS_DELEGATION_RETURN_DELAYED,
};
int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred,
fmode_t type, const nfs4_stateid *stateid, unsigned long pagemod_limit);
void nfs_inode_reclaim_delegation(struct inode *inode, const struct cred *cred,
fmode_t type, const nfs4_stateid *stateid, unsigned long pagemod_limit);
int nfs4_inode_return_delegation(struct inode *inode);
void nfs4_inode_return_delegation_on_close(struct inode *inode);
int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid);
void nfs_inode_evict_delegation(struct inode *inode);
struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs_fh *fhandle);
void nfs_server_return_all_delegations(struct nfs_server *);
void nfs_expire_all_delegations(struct nfs_client *clp);
void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags);
void nfs_expire_unreferenced_delegations(struct nfs_client *clp);
int nfs_client_return_marked_delegations(struct nfs_client *clp);
int nfs_delegations_present(struct nfs_client *clp);
void nfs_remove_bad_delegation(struct inode *inode, const nfs4_stateid *stateid);
void nfs_delegation_mark_returned(struct inode *inode, const nfs4_stateid *stateid);
void nfs_delegation_mark_reclaim(struct nfs_client *clp);
void nfs_delegation_reap_unclaimed(struct nfs_client *clp);
void nfs_mark_test_expired_all_delegations(struct nfs_client *clp);
void nfs_test_expired_all_delegations(struct nfs_client *clp);
void nfs_reap_expired_delegations(struct nfs_client *clp);
/* NFSv4 delegation-related procedures */
int nfs4_proc_delegreturn(struct inode *inode, const struct cred *cred, const nfs4_stateid *stateid, int issync);
int nfs4_open_delegation_recall(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid);
int nfs4_lock_delegation_recall(struct file_lock *fl, struct nfs4_state *state, const nfs4_stateid *stateid);
bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags, nfs4_stateid *dst, const struct cred **cred);
bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode);
struct nfs_delegation *nfs4_get_valid_delegation(const struct inode *inode);
void nfs_mark_delegation_referenced(struct nfs_delegation *delegation);
int nfs4_have_delegation(struct inode *inode, fmode_t flags);
int nfs4_check_delegation(struct inode *inode, fmode_t flags);
bool nfs4_delegation_flush_on_close(const struct inode *inode);
void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
const nfs4_stateid *stateid);
int nfs4_inode_make_writeable(struct inode *inode);
#endif
static inline int nfs_have_delegated_attributes(struct inode *inode)
{
return NFS_PROTO(inode)->have_delegation(inode, FMODE_READ);
}
#endif