/* * linux/include/linux/nfs_page.h * * Copyright (C) 2000 Trond Myklebust * * NFS page cache wrapper. */ #ifndef _LINUX_NFS_PAGE_H #define _LINUX_NFS_PAGE_H #include <linux/list.h> #include <linux/pagemap.h> #include <linux/wait.h> #include <linux/sunrpc/auth.h> #include <linux/nfs_xdr.h> #include <asm/atomic.h> /* * Valid flags for the radix tree */ #define NFS_PAGE_TAG_DIRTY 0 #define NFS_PAGE_TAG_WRITEBACK 1 /* * Valid flags for a dirty buffer */ #define PG_BUSY 0 #define PG_NEED_COMMIT 1 #define PG_NEED_RESCHED 2 #define PG_NEED_FLUSH 3 struct nfs_inode; struct nfs_page { struct list_head wb_list, /* Defines state of page: */ *wb_list_head; /* read/write/commit */ struct page *wb_page; /* page to read in/write out */ struct nfs_open_context *wb_context; /* File state context info */ atomic_t wb_complete; /* i/os we're waiting for */ unsigned long wb_index; /* Offset >> PAGE_CACHE_SHIFT */ unsigned int wb_offset, /* Offset & ~PAGE_CACHE_MASK */ wb_pgbase, /* Start of page data */ wb_bytes; /* Length of request */ atomic_t wb_count; /* reference count */ unsigned long wb_flags; struct nfs_writeverf wb_verf; /* Commit cookie */ }; #define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags)) #define NFS_NEED_COMMIT(req) (test_bit(PG_NEED_COMMIT,&(req)->wb_flags)) #define NFS_NEED_RESCHED(req) (test_bit(PG_NEED_RESCHED,&(req)->wb_flags)) extern struct nfs_page *nfs_create_request(struct nfs_open_context *ctx, struct inode *inode, struct page *page, unsigned int offset, unsigned int count); extern void nfs_clear_request(struct nfs_page *req); extern void nfs_release_request(struct nfs_page *req); extern long nfs_scan_dirty(struct address_space *mapping, struct writeback_control *wbc, struct list_head *dst); extern int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *head, struct list_head *dst, unsigned long idx_start, unsigned int npages); extern int nfs_coalesce_requests(struct list_head *, struct list_head *, unsigned int); extern int nfs_wait_on_request(struct nfs_page *); extern void nfs_unlock_request(struct nfs_page *req); extern int nfs_set_page_writeback_locked(struct nfs_page *req); extern void nfs_clear_page_writeback(struct nfs_page *req); /* * Lock the page of an asynchronous request without incrementing the wb_count */ static inline int nfs_lock_request_dontget(struct nfs_page *req) { return !test_and_set_bit(PG_BUSY, &req->wb_flags); } /* * Lock the page of an asynchronous request */ static inline int nfs_lock_request(struct nfs_page *req) { if (test_and_set_bit(PG_BUSY, &req->wb_flags)) return 0; atomic_inc(&req->wb_count); return 1; } /** * nfs_list_add_request - Insert a request into a list * @req: request * @head: head of list into which to insert the request. */ static inline void nfs_list_add_request(struct nfs_page *req, struct list_head *head) { list_add_tail(&req->wb_list, head); req->wb_list_head = head; } /** * nfs_list_remove_request - Remove a request from its wb_list * @req: request */ static inline void nfs_list_remove_request(struct nfs_page *req) { if (list_empty(&req->wb_list)) return; list_del_init(&req->wb_list); req->wb_list_head = NULL; } static inline int nfs_defer_commit(struct nfs_page *req) { return !test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags); } static inline void nfs_clear_commit(struct nfs_page *req) { smp_mb__before_clear_bit(); clear_bit(PG_NEED_COMMIT, &req->wb_flags); smp_mb__after_clear_bit(); } static inline int nfs_defer_reschedule(struct nfs_page *req) { return !test_and_set_bit(PG_NEED_RESCHED, &req->wb_flags); } static inline void nfs_clear_reschedule(struct nfs_page *req) { smp_mb__before_clear_bit(); clear_bit(PG_NEED_RESCHED, &req->wb_flags); smp_mb__after_clear_bit(); } static inline struct nfs_page * nfs_list_entry(struct list_head *head) { return list_entry(head, struct nfs_page, wb_list); } static inline loff_t req_offset(struct nfs_page *req) { return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset; } #endif /* _LINUX_NFS_PAGE_H */