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	Use the 'refcount_t' type instead of 'atomic_t' for improved refcounting safety. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
		
			
				
	
	
		
			64 lines
		
	
	
	
		
			2.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			64 lines
		
	
	
	
		
			2.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
#ifndef _FS_NFSD_FILECACHE_H
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#define _FS_NFSD_FILECACHE_H
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#include <linux/fsnotify_backend.h>
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/*
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 * This is the fsnotify_mark container that nfsd attaches to the files that it
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 * is holding open. Note that we have a separate refcount here aside from the
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 * one in the fsnotify_mark. We only want a single fsnotify_mark attached to
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 * the inode, and for each nfsd_file to hold a reference to it.
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 *
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 * The fsnotify_mark is itself refcounted, but that's not sufficient to tell us
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 * how to put that reference. If there are still outstanding nfsd_files that
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 * reference the mark, then we would want to call fsnotify_put_mark on it.
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 * If there were not, then we'd need to call fsnotify_destroy_mark. Since we
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 * can't really tell the difference, we use the nfm_mark to keep track of how
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 * many nfsd_files hold references to the mark. When that counter goes to zero
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 * then we know to call fsnotify_destroy_mark on it.
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 */
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struct nfsd_file_mark {
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	struct fsnotify_mark	nfm_mark;
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	refcount_t		nfm_ref;
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};
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/*
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 * A representation of a file that has been opened by knfsd. These are hashed
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 * in the hashtable by inode pointer value. Note that this object doesn't
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 * hold a reference to the inode by itself, so the nf_inode pointer should
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 * never be dereferenced, only used for comparison.
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 */
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struct nfsd_file {
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	struct hlist_node	nf_node;
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	struct list_head	nf_lru;
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	struct rcu_head		nf_rcu;
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	struct file		*nf_file;
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	const struct cred	*nf_cred;
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	struct net		*nf_net;
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#define NFSD_FILE_HASHED	(0)
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#define NFSD_FILE_PENDING	(1)
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#define NFSD_FILE_BREAK_READ	(2)
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#define NFSD_FILE_BREAK_WRITE	(3)
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#define NFSD_FILE_REFERENCED	(4)
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	unsigned long		nf_flags;
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	struct inode		*nf_inode;
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	unsigned int		nf_hashval;
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	refcount_t		nf_ref;
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	unsigned char		nf_may;
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	struct nfsd_file_mark	*nf_mark;
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	struct rw_semaphore	nf_rwsem;
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};
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int nfsd_file_cache_init(void);
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void nfsd_file_cache_purge(struct net *);
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void nfsd_file_cache_shutdown(void);
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int nfsd_file_cache_start_net(struct net *net);
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void nfsd_file_cache_shutdown_net(struct net *net);
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void nfsd_file_put(struct nfsd_file *nf);
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struct nfsd_file *nfsd_file_get(struct nfsd_file *nf);
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void nfsd_file_close_inode_sync(struct inode *inode);
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bool nfsd_file_is_cached(struct inode *inode);
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__be32 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
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		  unsigned int may_flags, struct nfsd_file **nfp);
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int	nfsd_file_cache_stats_open(struct inode *, struct file *);
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#endif /* _FS_NFSD_FILECACHE_H */
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