2 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
21 #include <linux/list.h>
22 #include <linux/types.h>
23 #include <linux/spinlock.h>
26 #include <linux/buffer_head.h>
27 #include <linux/uio.h>
33 #define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL))
36 XBRW_READ = 1, /* transfer into target memory */
37 XBRW_WRITE = 2, /* transfer from target memory */
38 XBRW_ZERO = 3, /* Zero target memory */
41 #define XBF_READ (1 << 0) /* buffer intended for reading from device */
42 #define XBF_WRITE (1 << 1) /* buffer intended for writing to device */
43 #define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */
44 #define XBF_MAPPED (1 << 3) /* buffer mapped (b_addr valid) */
45 #define XBF_ASYNC (1 << 4) /* initiator will not wait for completion */
46 #define XBF_DONE (1 << 5) /* all pages in the buffer uptodate */
47 #define XBF_STALE (1 << 6) /* buffer has been staled, do not find it */
49 /* I/O hints for the BIO layer */
50 #define XBF_SYNCIO (1 << 10)/* treat this buffer as synchronous I/O */
51 #define XBF_FUA (1 << 11)/* force cache write through mode */
52 #define XBF_FLUSH (1 << 12)/* flush the disk cache before a write */
54 /* flags used only as arguments to access routines */
55 #define XBF_LOCK (1 << 15)/* lock requested */
56 #define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */
57 #define XBF_DONT_BLOCK (1 << 17)/* do not block in current thread */
59 /* flags used only internally */
60 #define _XBF_PAGES (1 << 20)/* backed by refcounted pages */
61 #define _XBF_KMEM (1 << 21)/* backed by heap memory */
62 #define _XBF_DELWRI_Q (1 << 22)/* buffer on a delwri queue */
64 typedef unsigned int xfs_buf_flags_t;
66 #define XFS_BUF_FLAGS \
67 { XBF_READ, "READ" }, \
68 { XBF_WRITE, "WRITE" }, \
69 { XBF_READ_AHEAD, "READ_AHEAD" }, \
70 { XBF_MAPPED, "MAPPED" }, \
71 { XBF_ASYNC, "ASYNC" }, \
72 { XBF_DONE, "DONE" }, \
73 { XBF_STALE, "STALE" }, \
74 { XBF_SYNCIO, "SYNCIO" }, \
76 { XBF_FLUSH, "FLUSH" }, \
77 { XBF_LOCK, "LOCK" }, /* should never be set */\
78 { XBF_TRYLOCK, "TRYLOCK" }, /* ditto */\
79 { XBF_DONT_BLOCK, "DONT_BLOCK" }, /* ditto */\
80 { _XBF_PAGES, "PAGES" }, \
81 { _XBF_KMEM, "KMEM" }, \
82 { _XBF_DELWRI_Q, "DELWRI_Q" }
84 typedef struct xfs_buftarg {
86 struct block_device *bt_bdev;
87 struct backing_dev_info *bt_bdi;
88 struct xfs_mount *bt_mount;
89 unsigned int bt_bsize;
90 unsigned int bt_sshift;
93 /* LRU control structures */
94 struct shrinker bt_shrinker;
95 struct list_head bt_lru;
96 spinlock_t bt_lru_lock;
97 unsigned int bt_lru_nr;
101 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
105 typedef struct xfs_buf {
107 * first cacheline holds all the fields needed for an uncontended cache
108 * hit to be fully processed. The semaphore straddles the cacheline
109 * boundary, but the counter and lock sits on the first cacheline,
110 * which is the only bit that is touched if we hit the semaphore
111 * fast-path on locking.
113 struct rb_node b_rbnode; /* rbtree node */
114 xfs_daddr_t b_bn; /* block number for I/O */
115 int b_length; /* size of buffer in BBs */
116 atomic_t b_hold; /* reference count */
117 atomic_t b_lru_ref; /* lru reclaim ref count */
118 xfs_buf_flags_t b_flags; /* status flags */
119 struct semaphore b_sema; /* semaphore for lockables */
121 struct list_head b_lru; /* lru list */
122 wait_queue_head_t b_waiters; /* unpin waiters */
123 struct list_head b_list;
124 struct xfs_perag *b_pag; /* contains rbtree root */
125 xfs_buftarg_t *b_target; /* buffer target (device) */
126 void *b_addr; /* virtual address of buffer */
127 struct work_struct b_iodone_work;
128 xfs_buf_iodone_t b_iodone; /* I/O completion function */
129 struct completion b_iowait; /* queue for I/O waiters */
131 struct xfs_trans *b_transp;
132 struct page **b_pages; /* array of page pointers */
133 struct page *b_page_array[XB_PAGES]; /* inline pages */
134 int b_io_length; /* IO size in BBs */
135 atomic_t b_pin_count; /* pin count */
136 atomic_t b_io_remaining; /* #outstanding I/O requests */
137 unsigned int b_page_count; /* size of page array */
138 unsigned int b_offset; /* page offset in first page */
139 unsigned short b_error; /* error code on I/O */
140 #ifdef XFS_BUF_LOCK_TRACKING
146 /* Finding and Reading Buffers */
147 struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target, xfs_daddr_t blkno,
148 size_t numblks, xfs_buf_flags_t flags,
149 struct xfs_buf *new_bp);
150 #define xfs_incore(buftarg,blkno,len,lockit) \
151 _xfs_buf_find(buftarg, blkno ,len, lockit, NULL)
153 struct xfs_buf *xfs_buf_get(struct xfs_buftarg *target, xfs_daddr_t blkno,
154 size_t numblks, xfs_buf_flags_t flags);
155 struct xfs_buf *xfs_buf_read(struct xfs_buftarg *target, xfs_daddr_t blkno,
156 size_t numblks, xfs_buf_flags_t flags);
157 void xfs_buf_readahead(struct xfs_buftarg *target, xfs_daddr_t blkno,
160 struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks);
161 struct xfs_buf *xfs_buf_alloc(struct xfs_buftarg *target, xfs_daddr_t blkno,
162 size_t numblks, xfs_buf_flags_t flags);
163 void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks);
164 int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length);
166 struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
168 struct xfs_buf *xfs_buf_read_uncached(struct xfs_buftarg *target,
169 xfs_daddr_t daddr, size_t numblks, int flags);
170 void xfs_buf_hold(struct xfs_buf *bp);
172 /* Releasing Buffers */
173 extern void xfs_buf_free(xfs_buf_t *);
174 extern void xfs_buf_rele(xfs_buf_t *);
176 /* Locking and Unlocking Buffers */
177 extern int xfs_buf_trylock(xfs_buf_t *);
178 extern void xfs_buf_lock(xfs_buf_t *);
179 extern void xfs_buf_unlock(xfs_buf_t *);
180 #define xfs_buf_islocked(bp) \
181 ((bp)->b_sema.count <= 0)
183 /* Buffer Read and Write Routines */
184 extern int xfs_bwrite(struct xfs_buf *bp);
186 extern void xfsbdstrat(struct xfs_mount *, struct xfs_buf *);
187 extern int xfs_bdstrat_cb(struct xfs_buf *);
189 extern void xfs_buf_ioend(xfs_buf_t *, int);
190 extern void xfs_buf_ioerror(xfs_buf_t *, int);
191 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func);
192 extern void xfs_buf_iorequest(xfs_buf_t *);
193 extern int xfs_buf_iowait(xfs_buf_t *);
194 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *,
196 #define xfs_buf_zero(bp, off, len) \
197 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
199 static inline int xfs_buf_geterror(xfs_buf_t *bp)
201 return bp ? bp->b_error : ENOMEM;
204 /* Buffer Utility Routines */
205 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
207 /* Delayed Write Buffer Routines */
208 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
209 extern int xfs_buf_delwri_submit(struct list_head *);
210 extern int xfs_buf_delwri_submit_nowait(struct list_head *);
212 /* Buffer Daemon Setup Routines */
213 extern int xfs_buf_init(void);
214 extern void xfs_buf_terminate(void);
216 #define XFS_BUF_ZEROFLAGS(bp) \
217 ((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC| \
218 XBF_SYNCIO|XBF_FUA|XBF_FLUSH))
220 void xfs_buf_stale(struct xfs_buf *bp);
221 #define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE)
222 #define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE)
224 #define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE)
225 #define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE)
226 #define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE)
228 #define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC)
229 #define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC)
230 #define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC)
232 #define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ)
233 #define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ)
234 #define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ)
236 #define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE)
237 #define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE)
238 #define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE)
240 #define XFS_BUF_ADDR(bp) ((bp)->b_bn)
241 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_bn = (xfs_daddr_t)(bno))
243 static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref)
245 atomic_set(&bp->b_lru_ref, lru_ref);
248 static inline int xfs_buf_ispinned(struct xfs_buf *bp)
250 return atomic_read(&bp->b_pin_count);
253 static inline void xfs_buf_relse(xfs_buf_t *bp)
260 * Handling of buftargs.
262 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *,
263 struct block_device *, int, const char *);
264 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
265 extern void xfs_wait_buftarg(xfs_buftarg_t *);
266 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
268 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
269 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
271 #endif /* __XFS_BUF_H__ */