nfs_fs.h

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/*
 *  linux/include/linux/nfs_fs.h
 *
 *  Copyright (C) 1992  Rick Sladkey
 *
 *  OS-specific nfs filesystem definitions and declarations
 */

#ifndef _LINUX_NFS_FS_H
#define _LINUX_NFS_FS_H

#include <linux/config.h>
#include <linux/in.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/rwsem.h>
#include <linux/wait.h>

#include <linux/nfs_fs_sb.h>

#include <linux/sunrpc/debug.h>
#include <linux/sunrpc/auth.h>
#include <linux/sunrpc/clnt.h>

#include <linux/nfs.h>
#include <linux/nfs2.h>
#include <linux/nfs3.h>
#include <linux/nfs4.h>
#include <linux/nfs_xdr.h>
#include <linux/rwsem.h>
#include <linux/mempool.h>

/*
 * Enable debugging support for nfs client.
 * Requires RPC_DEBUG.
 */
#ifdef RPC_DEBUG
# define NFS_DEBUG
#endif

#define NFS_MAX_FILE_IO_BUFFER_SIZE	32768
#define NFS_DEF_FILE_IO_BUFFER_SIZE	4096

/*
 * superblock magic number for NFS
 */
#define NFS_SUPER_MAGIC			0x6969

/*
 * These are the default flags for swap requests
 */
#define NFS_RPC_SWAPFLAGS		(RPC_TASK_SWAPPER|RPC_TASK_ROOTCREDS)

/*
 * When flushing a cluster of dirty pages, there can be different
 * strategies:
 */
#define FLUSH_AGING		0	/* only flush old buffers */
#define FLUSH_SYNC		1	/* file being synced, or contention */
#define FLUSH_WAIT		2	/* wait for completion */
#define FLUSH_STABLE		4	/* commit to stable storage */
#define FLUSH_LOWPRI		8	/* low priority background flush */
#define FLUSH_HIGHPRI		16	/* high priority memory reclaim flush */

#ifdef __KERNEL__

/*
 * NFSv3/v4 Access mode cache entry
 */
struct nfs_access_entry {
	unsigned long		jiffies;
	struct rpc_cred *	cred;
	int			mask;
};

struct nfs4_state;
struct nfs_open_context {
	atomic_t count;
	struct dentry *dentry;
	struct rpc_cred *cred;
	struct nfs4_state *state;
	fl_owner_t lockowner;
	int mode;
	int error;

	struct list_head list;

	__u64 dir_cookie;
};

/*
 * NFSv4 delegation
 */
struct nfs_delegation;

struct posix_acl;

/*
 * nfs fs inode data in memory
 */
struct nfs_inode {
	/*
	 * The 64bit 'inode number'
	 */
	__u64 fileid;

	/*
	 * NFS file handle
	 */
	struct nfs_fh		fh;

	/*
	 * Various flags
	 */
	unsigned long		flags;			/* atomic bit ops */
	unsigned long		cache_validity;		/* bit mask */

	/*
	 * read_cache_jiffies is when we started read-caching this inode,
	 * and read_cache_mtime is the mtime of the inode at that time.
	 * attrtimeo is for how long the cached information is assumed
	 * to be valid. A successful attribute revalidation doubles
	 * attrtimeo (up to acregmax/acdirmax), a failure resets it to
	 * acregmin/acdirmin.
	 *
	 * We need to revalidate the cached attrs for this inode if
	 *
	 *	jiffies - read_cache_jiffies > attrtimeo
	 *
	 * and invalidate any cached data/flush out any dirty pages if
	 * we find that
	 *
	 *	mtime != read_cache_mtime
	 */
	unsigned long		read_cache_jiffies;
	unsigned long		attrtimeo;
	unsigned long		attrtimeo_timestamp;
	__u64			change_attr;		/* v4 only */

	/* "Generation counter" for the attribute cache. This is
	 * bumped whenever we update the metadata on the
	 * server.
	 */
	unsigned long		cache_change_attribute;
	/*
	 * Counter indicating the number of outstanding requests that
	 * will cause a file data update.
	 */
	atomic_t		data_updates;

	struct nfs_access_entry	cache_access;
#ifdef CONFIG_NFS_V3_ACL
	struct posix_acl	*acl_access;
	struct posix_acl	*acl_default;
#endif

	/*
	 * This is the cookie verifier used for NFSv3 readdir
	 * operations
	 */
	__u32			cookieverf[2];

	/*
	 * This is the list of dirty unwritten pages.
	 */
	spinlock_t		req_lock;
	struct list_head	dirty;
	struct list_head	commit;
	struct radix_tree_root	nfs_page_tree;

	unsigned int		ndirty,
				ncommit,
				npages;

	/* Open contexts for shared mmap writes */
	struct list_head	open_files;

#ifdef CONFIG_NFS_V4
	struct nfs4_cached_acl	*nfs4_acl;
        /* NFSv4 state */
	struct list_head	open_states;
	struct nfs_delegation	*delegation;
	int			 delegation_state;
	struct rw_semaphore	rwsem;
#endif /* CONFIG_NFS_V4*/
	struct inode		vfs_inode;
};

/*
 * Cache validity bit flags
 */
#define NFS_INO_INVALID_ATTR	0x0001		/* cached attrs are invalid */
#define NFS_INO_INVALID_DATA	0x0002		/* cached data is invalid */
#define NFS_INO_INVALID_ATIME	0x0004		/* cached atime is invalid */
#define NFS_INO_INVALID_ACCESS	0x0008		/* cached access cred invalid */
#define NFS_INO_INVALID_ACL	0x0010		/* cached acls are invalid */
#define NFS_INO_REVAL_PAGECACHE	0x0020		/* must revalidate pagecache */

/*
 * Bit offsets in flags field
 */
#define NFS_INO_REVALIDATING	(0)		/* revalidating attrs */
#define NFS_INO_ADVISE_RDPLUS	(1)		/* advise readdirplus */
#define NFS_INO_STALE		(2)		/* possible stale inode */

static inline struct nfs_inode *NFS_I(struct inode *inode)
{
	return container_of(inode, struct nfs_inode, vfs_inode);
}
#define NFS_SB(s)		((struct nfs_server *)(s->s_fs_info))

#define NFS_FH(inode)			(&NFS_I(inode)->fh)
#define NFS_SERVER(inode)		(NFS_SB(inode->i_sb))
#define NFS_CLIENT(inode)		(NFS_SERVER(inode)->client)
#define NFS_PROTO(inode)		(NFS_SERVER(inode)->rpc_ops)
#define NFS_ADDR(inode)			(RPC_PEERADDR(NFS_CLIENT(inode)))
#define NFS_COOKIEVERF(inode)		(NFS_I(inode)->cookieverf)
#define NFS_READTIME(inode)		(NFS_I(inode)->read_cache_jiffies)
#define NFS_CHANGE_ATTR(inode)		(NFS_I(inode)->change_attr)
#define NFS_ATTRTIMEO(inode)		(NFS_I(inode)->attrtimeo)
#define NFS_MINATTRTIMEO(inode) \
	(S_ISDIR(inode->i_mode)? NFS_SERVER(inode)->acdirmin \
			       : NFS_SERVER(inode)->acregmin)
#define NFS_MAXATTRTIMEO(inode) \
	(S_ISDIR(inode->i_mode)? NFS_SERVER(inode)->acdirmax \
			       : NFS_SERVER(inode)->acregmax)
#define NFS_ATTRTIMEO_UPDATE(inode)	(NFS_I(inode)->attrtimeo_timestamp)

#define NFS_FLAGS(inode)		(NFS_I(inode)->flags)
#define NFS_STALE(inode)		(test_bit(NFS_INO_STALE, &NFS_FLAGS(inode)))

#define NFS_FILEID(inode)		(NFS_I(inode)->fileid)

static inline int nfs_caches_unstable(struct inode *inode)
{
	return atomic_read(&NFS_I(inode)->data_updates) != 0;
}

static inline void NFS_CACHEINV(struct inode *inode)
{
	if (!nfs_caches_unstable(inode)) {
		spin_lock(&inode->i_lock);
		NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATTR | NFS_INO_INVALID_ACCESS;
		spin_unlock(&inode->i_lock);
	}
}

static inline int nfs_server_capable(struct inode *inode, int cap)
{
	return NFS_SERVER(inode)->caps & cap;
}

static inline int NFS_USE_READDIRPLUS(struct inode *inode)
{
	return test_bit(NFS_INO_ADVISE_RDPLUS, &NFS_FLAGS(inode));
}

/**
 * nfs_save_change_attribute - Returns the inode attribute change cookie
 * @inode - pointer to inode
 * The "change attribute" is updated every time we finish an operation
 * that will result in a metadata change on the server.
 */
static inline long nfs_save_change_attribute(struct inode *inode)
{
	return NFS_I(inode)->cache_change_attribute;
}

/**
 * nfs_verify_change_attribute - Detects NFS inode cache updates
 * @inode - pointer to inode
 * @chattr - previously saved change attribute
 * Return "false" if metadata has been updated (or is in the process of
 * being updated) since the change attribute was saved.
 */
static inline int nfs_verify_change_attribute(struct inode *inode, unsigned long chattr)
{
	return !nfs_caches_unstable(inode)
		&& chattr == NFS_I(inode)->cache_change_attribute;
}

/*
 * linux/fs/nfs/inode.c
 */
extern void nfs_zap_caches(struct inode *);
extern struct inode *nfs_fhget(struct super_block *, struct nfs_fh *,
				struct nfs_fattr *);
extern int nfs_refresh_inode(struct inode *, struct nfs_fattr *);
extern int nfs_getattr(struct vfsmount *, struct dentry *, struct kstat *);
extern int nfs_permission(struct inode *, int, struct nameidata *);
extern int nfs_access_get_cached(struct inode *, struct rpc_cred *, struct nfs_access_entry *);
extern void nfs_access_add_cache(struct inode *, struct nfs_access_entry *);
extern int nfs_open(struct inode *, struct file *);