| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/include/linux/nfs_page.h |
| 3 | * |
| 4 | * Copyright (C) 2000 Trond Myklebust |
| 5 | * |
| 6 | * NFS page cache wrapper. |
| 7 | */ |
| 8 | |
| 9 | #ifndef _LINUX_NFS_PAGE_H |
| 10 | #define _LINUX_NFS_PAGE_H |
| 11 | |
| 12 | |
| 13 | #include <linux/list.h> |
| 14 | #include <linux/pagemap.h> |
| 15 | #include <linux/wait.h> |
| 16 | #include <linux/nfs_fs_sb.h> |
| 17 | #include <linux/sunrpc/auth.h> |
| 18 | #include <linux/nfs_xdr.h> |
| 19 | |
| 20 | #include <asm/atomic.h> |
| 21 | |
| 22 | /* |
| 23 | * Valid flags for a dirty buffer |
| 24 | */ |
| 25 | #define PG_BUSY 0 |
| 26 | #define PG_NEED_COMMIT 1 |
| 27 | #define PG_NEED_RESCHED 2 |
| 28 | |
| 29 | struct nfs_page { |
| 30 | struct list_head wb_list, /* Defines state of page: */ |
| 31 | *wb_list_head; /* read/write/commit */ |
| 32 | struct page *wb_page; /* page to read in/write out */ |
| 33 | struct nfs_open_context *wb_context; /* File state context info */ |
| 34 | atomic_t wb_complete; /* i/os we're waiting for */ |
| 35 | unsigned long wb_index; /* Offset >> PAGE_CACHE_SHIFT */ |
| 36 | unsigned int wb_offset, /* Offset & ~PAGE_CACHE_MASK */ |
| 37 | wb_pgbase, /* Start of page data */ |
| 38 | wb_bytes; /* Length of request */ |
| 39 | atomic_t wb_count; /* reference count */ |
| 40 | unsigned long wb_flags; |
| 41 | struct nfs_writeverf wb_verf; /* Commit cookie */ |
| 42 | }; |
| 43 | |
| 44 | #define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags)) |
| 45 | #define NFS_NEED_COMMIT(req) (test_bit(PG_NEED_COMMIT,&(req)->wb_flags)) |
| 46 | #define NFS_NEED_RESCHED(req) (test_bit(PG_NEED_RESCHED,&(req)->wb_flags)) |
| 47 | |
| 48 | extern struct nfs_page *nfs_create_request(struct nfs_open_context *ctx, |
| 49 | struct inode *inode, |
| 50 | struct page *page, |
| 51 | unsigned int offset, |
| 52 | unsigned int count); |
| 53 | extern void nfs_clear_request(struct nfs_page *req); |
| 54 | extern void nfs_release_request(struct nfs_page *req); |
| 55 | |
| 56 | |
| 57 | extern void nfs_list_add_request(struct nfs_page *, struct list_head *); |
| 58 | |
| 59 | extern int nfs_scan_list(struct list_head *, struct list_head *, |
| 60 | unsigned long, unsigned int); |
| 61 | extern int nfs_coalesce_requests(struct list_head *, struct list_head *, |
| 62 | unsigned int); |
| 63 | extern int nfs_wait_on_request(struct nfs_page *); |
| 64 | extern void nfs_unlock_request(struct nfs_page *req); |
| 65 | |
| 66 | /* |
| 67 | * Lock the page of an asynchronous request without incrementing the wb_count |
| 68 | */ |
| 69 | static inline int |
| 70 | nfs_lock_request_dontget(struct nfs_page *req) |
| 71 | { |
| 72 | if (test_and_set_bit(PG_BUSY, &req->wb_flags)) |
| 73 | return 0; |
| 74 | return 1; |
| 75 | } |
| 76 | |
| 77 | /* |
| 78 | * Lock the page of an asynchronous request |
| 79 | */ |
| 80 | static inline int |
| 81 | nfs_lock_request(struct nfs_page *req) |
| 82 | { |
| 83 | if (test_and_set_bit(PG_BUSY, &req->wb_flags)) |
| 84 | return 0; |
| 85 | atomic_inc(&req->wb_count); |
| 86 | return 1; |
| 87 | } |
| 88 | |
| 89 | |
| 90 | /** |
| 91 | * nfs_list_remove_request - Remove a request from its wb_list |
| 92 | * @req: request |
| 93 | */ |
| 94 | static inline void |
| 95 | nfs_list_remove_request(struct nfs_page *req) |
| 96 | { |
| 97 | if (list_empty(&req->wb_list)) |
| 98 | return; |
| 99 | if (!NFS_WBACK_BUSY(req)) { |
| 100 | printk(KERN_ERR "NFS: unlocked request attempted removed from list!\n"); |
| 101 | BUG(); |
| 102 | } |
| 103 | list_del_init(&req->wb_list); |
| 104 | req->wb_list_head = NULL; |
| 105 | } |
| 106 | |
| 107 | static inline int |
| 108 | nfs_defer_commit(struct nfs_page *req) |
| 109 | { |
| 110 | if (test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags)) |
| 111 | return 0; |
| 112 | return 1; |
| 113 | } |
| 114 | |
| 115 | static inline void |
| 116 | nfs_clear_commit(struct nfs_page *req) |
| 117 | { |
| 118 | smp_mb__before_clear_bit(); |
| 119 | clear_bit(PG_NEED_COMMIT, &req->wb_flags); |
| 120 | smp_mb__after_clear_bit(); |
| 121 | } |
| 122 | |
| 123 | static inline int |
| 124 | nfs_defer_reschedule(struct nfs_page *req) |
| 125 | { |
| 126 | if (test_and_set_bit(PG_NEED_RESCHED, &req->wb_flags)) |
| 127 | return 0; |
| 128 | return 1; |
| 129 | } |
| 130 | |
| 131 | static inline void |
| 132 | nfs_clear_reschedule(struct nfs_page *req) |
| 133 | { |
| 134 | smp_mb__before_clear_bit(); |
| 135 | clear_bit(PG_NEED_RESCHED, &req->wb_flags); |
| 136 | smp_mb__after_clear_bit(); |
| 137 | } |
| 138 | |
| 139 | static inline struct nfs_page * |
| 140 | nfs_list_entry(struct list_head *head) |
| 141 | { |
| 142 | return list_entry(head, struct nfs_page, wb_list); |
| 143 | } |
| 144 | |
| 145 | static inline |
| 146 | loff_t req_offset(struct nfs_page *req) |
| 147 | { |
| 148 | return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset; |
| 149 | } |
| 150 | |
| 151 | #endif /* _LINUX_NFS_PAGE_H */ |