fs/xfs/xfs_buf.h

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
   4  * All Rights Reserved.
   5  */
   6 #ifndef __XFS_BUF_H__
   7 #define __XFS_BUF_H__
   8
   9 #include <linux/list.h>
  10 #include <linux/types.h>
  11 #include <linux/spinlock.h>
  12 #include <linux/mm.h>
  13 #include <linux/fs.h>
  14 #include <linux/dax.h>
  15 #include <linux/uio.h>
  16 #include <linux/list_lru.h>
  17
  18 /*
  19  *      Base types
  20  */
  21 struct xfs_buf;
  22
  23 #define XFS_BUF_DADDR_NULL      ((xfs_daddr_t) (-1LL))
  24
  25 #define XBF_READ         (1 << 0) /* buffer intended for reading from device */
  26 #define XBF_WRITE        (1 << 1) /* buffer intended for writing to device */
  27 #define XBF_READ_AHEAD   (1 << 2) /* asynchronous read-ahead */
  28 #define XBF_NO_IOACCT    (1 << 3) /* bypass I/O accounting (non-LRU bufs) */
  29 #define XBF_ASYNC        (1 << 4) /* initiator will not wait for completion */
  30 #define XBF_DONE         (1 << 5) /* all pages in the buffer uptodate */
  31 #define XBF_STALE        (1 << 6) /* buffer has been staled, do not find it */
  32 #define XBF_WRITE_FAIL   (1 << 7) /* async writes have failed on this buffer */
  33
  34 /* buffer type flags for write callbacks */
  35 #define _XBF_INODES      (1 << 16)/* inode buffer */
  36 #define _XBF_DQUOTS      (1 << 17)/* dquot buffer */
  37 #define _XBF_LOGRECOVERY         (1 << 18)/* log recovery buffer */
  38
  39 /* flags used only internally */
  40 #define _XBF_PAGES       (1 << 20)/* backed by refcounted pages */
  41 #define _XBF_KMEM        (1 << 21)/* backed by heap memory */
  42 #define _XBF_DELWRI_Q    (1 << 22)/* buffer on a delwri queue */
  43
  44 /* flags used only as arguments to access routines */
  45 #define XBF_TRYLOCK      (1 << 30)/* lock requested, but do not wait */
  46 #define XBF_UNMAPPED     (1 << 31)/* do not map the buffer */
  47
  48 typedef unsigned int xfs_buf_flags_t;
  49
  50 #define XFS_BUF_FLAGS \
  51         { XBF_READ,             "READ" }, \
  52         { XBF_WRITE,            "WRITE" }, \
  53         { XBF_READ_AHEAD,       "READ_AHEAD" }, \
  54         { XBF_NO_IOACCT,        "NO_IOACCT" }, \
  55         { XBF_ASYNC,            "ASYNC" }, \
  56         { XBF_DONE,             "DONE" }, \
  57         { XBF_STALE,            "STALE" }, \
  58         { XBF_WRITE_FAIL,       "WRITE_FAIL" }, \
  59         { _XBF_INODES,          "INODES" }, \
  60         { _XBF_DQUOTS,          "DQUOTS" }, \
  61         { _XBF_LOGRECOVERY,             "LOG_RECOVERY" }, \
  62         { _XBF_PAGES,           "PAGES" }, \
  63         { _XBF_KMEM,            "KMEM" }, \
  64         { _XBF_DELWRI_Q,        "DELWRI_Q" }, \
  65         /* The following interface flags should never be set */ \
  66         { XBF_TRYLOCK,          "TRYLOCK" }, \
  67         { XBF_UNMAPPED,         "UNMAPPED" }
  68
  69 /*
  70  * Internal state flags.
  71  */
  72 #define XFS_BSTATE_DISPOSE       (1 << 0)       /* buffer being discarded */
  73 #define XFS_BSTATE_IN_FLIGHT     (1 << 1)       /* I/O in flight */
  74
  75 /*
  76  * The xfs_buftarg contains 2 notions of "sector size" -
  77  *
  78  * 1) The metadata sector size, which is the minimum unit and
  79  *    alignment of IO which will be performed by metadata operations.
  80  * 2) The device logical sector size
  81  *
  82  * The first is specified at mkfs time, and is stored on-disk in the
  83  * superblock's sb_sectsize.
  84  *
  85  * The latter is derived from the underlying device, and controls direct IO
  86  * alignment constraints.
  87  */
  88 typedef struct xfs_buftarg {
  89         dev_t                   bt_dev;
  90         struct block_device     *bt_bdev;
  91         struct dax_device       *bt_daxdev;
  92         struct xfs_mount        *bt_mount;
  93         unsigned int            bt_meta_sectorsize;
  94         size_t                  bt_meta_sectormask;
  95         size_t                  bt_logical_sectorsize;
  96         size_t                  bt_logical_sectormask;
  97
  98         /* LRU control structures */
  99         struct shrinker         bt_shrinker;
 100         struct list_lru         bt_lru;
 101
 102         struct percpu_counter   bt_io_count;
 103         struct ratelimit_state  bt_ioerror_rl;
 104 } xfs_buftarg_t;
 105
 106 #define XB_PAGES        2
 107
 108 struct xfs_buf_map {
 109         xfs_daddr_t             bm_bn;  /* block number for I/O */
 110         int                     bm_len; /* size of I/O */
 111 };
 112
 113 #define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
 114         struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };
 115
 116 struct xfs_buf_ops {
 117         char *name;
 118         union {
 119                 __be32 magic[2];        /* v4 and v5 on disk magic values */
 120                 __be16 magic16[2];      /* v4 and v5 on disk magic values */
 121         };
 122         void (*verify_read)(struct xfs_buf *);
 123         void (*verify_write)(struct xfs_buf *);
 124         xfs_failaddr_t (*verify_struct)(struct xfs_buf *bp);
 125 };
 126
 127 struct xfs_buf {
 128         /*
 129          * first cacheline holds all the fields needed for an uncontended cache
 130          * hit to be fully processed. The semaphore straddles the cacheline
 131          * boundary, but the counter and lock sits on the first cacheline,
 132          * which is the only bit that is touched if we hit the semaphore
 133          * fast-path on locking.
 134          */
 135         struct rhash_head       b_rhash_head;   /* pag buffer hash node */
 136
 137         /*
 138          * b_bn is the cache index. Do not use directly, use b_maps[0].bm_bn
 139          * for the buffer disk address instead.
 140          */
 141         xfs_daddr_t             b_bn;
 142         int                     b_length;       /* size of buffer in BBs */
 143         atomic_t                b_hold;         /* reference count */
 144         atomic_t                b_lru_ref;      /* lru reclaim ref count */
 145         xfs_buf_flags_t         b_flags;        /* status flags */
 146         struct semaphore        b_sema;         /* semaphore for lockables */
 147
 148         /*
 149          * concurrent access to b_lru and b_lru_flags are protected by
 150          * bt_lru_lock and not by b_sema
 151          */
 152         struct list_head        b_lru;          /* lru list */
 153         spinlock_t              b_lock;         /* internal state lock */
 154         unsigned int            b_state;        /* internal state flags */
 155         int                     b_io_error;     /* internal IO error state */
 156         wait_queue_head_t       b_waiters;      /* unpin waiters */
 157         struct list_head        b_list;
 158         struct xfs_perag        *b_pag;         /* contains rbtree root */
 159         struct xfs_mount        *b_mount;
 160         struct xfs_buftarg      *b_target;      /* buffer target (device) */
 161         void                    *b_addr;        /* virtual address of buffer */
 162         struct work_struct      b_ioend_work;
 163         struct completion       b_iowait;       /* queue for I/O waiters */
 164         struct xfs_buf_log_item *b_log_item;
 165         struct list_head        b_li_list;      /* Log items list head */
 166         struct xfs_trans        *b_transp;
 167         struct page             **b_pages;      /* array of page pointers */
 168         struct page             *b_page_array[XB_PAGES]; /* inline pages */
 169         struct xfs_buf_map      *b_maps;        /* compound buffer map */
 170         struct xfs_buf_map      __b_map;        /* inline compound buffer map */
 171         int                     b_map_count;
 172         atomic_t                b_pin_count;    /* pin count */
 173         atomic_t                b_io_remaining; /* #outstanding I/O requests */
 174         unsigned int            b_page_count;   /* size of page array */
 175         unsigned int            b_offset;       /* page offset of b_addr,
 176                                                    only for _XBF_KMEM buffers */
 177         int                     b_error;        /* error code on I/O */
 178
 179         /*
 180          * async write failure retry count. Initialised to zero on the first
 181          * failure, then when it exceeds the maximum configured without a
 182          * success the write is considered to be failed permanently and the
 183          * iodone handler will take appropriate action.
 184          *
 185          * For retry timeouts, we record the jiffie of the first failure. This
 186          * means that we can change the retry timeout for buffers already under
 187          * I/O and thus avoid getting stuck in a retry loop with a long timeout.
 188          *
 189          * last_error is used to ensure that we are getting repeated errors, not
 190          * different errors. e.g. a block device might change ENOSPC to EIO when
 191          * a failure timeout occurs, so we want to re-initialise the error
 192          * retry behaviour appropriately when that happens.
 193          */
 194         int                     b_retries;
 195         unsigned long           b_first_retry_time; /* in jiffies */
 196         int                     b_last_error;
 197
 198         const struct xfs_buf_ops        *b_ops;
 199 };
 200
 201 /* Finding and Reading Buffers */
 202 struct xfs_buf *xfs_buf_incore(struct xfs_buftarg *target,
 203                            xfs_daddr_t blkno, size_t numblks,
 204                            xfs_buf_flags_t flags);
 205
 206 int xfs_buf_get_map(struct xfs_buftarg *target, struct xfs_buf_map *map,
 207                 int nmaps, xfs_buf_flags_t flags, struct xfs_buf **bpp);
 208 int xfs_buf_read_map(struct xfs_buftarg *target, struct xfs_buf_map *map,
 209                 int nmaps, xfs_buf_flags_t flags, struct xfs_buf **bpp,
 210                 const struct xfs_buf_ops *ops, xfs_failaddr_t fa);
 211 void xfs_buf_readahead_map(struct xfs_buftarg *target,
 212                                struct xfs_buf_map *map, int nmaps,
 213                                const struct xfs_buf_ops *ops);
 214
 215 static inline int
 216 xfs_buf_get(
 217         struct xfs_buftarg      *target,
 218         xfs_daddr_t             blkno,
 219         size_t                  numblks,
 220         struct xfs_buf          **bpp)
 221 {
 222         DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
 223
 224         return xfs_buf_get_map(target, &map, 1, 0, bpp);
 225 }
 226
 227 static inline int
 228 xfs_buf_read(
 229         struct xfs_buftarg      *target,
 230         xfs_daddr_t             blkno,
 231         size_t                  numblks,
 232         xfs_buf_flags_t         flags,
 233         struct xfs_buf          **bpp,
 234         const struct xfs_buf_ops *ops)
 235 {
 236         DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
 237
 238         return xfs_buf_read_map(target, &map, 1, flags, bpp, ops,
 239                         __builtin_return_address(0));
 240 }
 241
 242 static inline void
 243 xfs_buf_readahead(
 244         struct xfs_buftarg      *target,
 245         xfs_daddr_t             blkno,
 246         size_t                  numblks,
 247         const struct xfs_buf_ops *ops)
 248 {
 249         DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
 250         return xfs_buf_readahead_map(target, &map, 1, ops);
 251 }
 252
 253 int xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks, int flags,
 254                 struct xfs_buf **bpp);
 255 int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr,
 256                           size_t numblks, int flags, struct xfs_buf **bpp,
 257                           const struct xfs_buf_ops *ops);
 258 int _xfs_buf_read(struct xfs_buf *bp, xfs_buf_flags_t flags);
 259 void xfs_buf_hold(struct xfs_buf *bp);
 260
 261 /* Releasing Buffers */
 262 extern void xfs_buf_rele(struct xfs_buf *);
 263
 264 /* Locking and Unlocking Buffers */
 265 extern int xfs_buf_trylock(struct xfs_buf *);
 266 extern void xfs_buf_lock(struct xfs_buf *);
 267 extern void xfs_buf_unlock(struct xfs_buf *);
 268 #define xfs_buf_islocked(bp) \
 269         ((bp)->b_sema.count <= 0)
 270
 271 static inline void xfs_buf_relse(struct xfs_buf *bp)
 272 {
 273         xfs_buf_unlock(bp);
 274         xfs_buf_rele(bp);
 275 }
 276
 277 /* Buffer Read and Write Routines */
 278 extern int xfs_bwrite(struct xfs_buf *bp);
 279
 280 extern void __xfs_buf_ioerror(struct xfs_buf *bp, int error,
 281                 xfs_failaddr_t failaddr);
 282 #define xfs_buf_ioerror(bp, err) __xfs_buf_ioerror((bp), (err), __this_address)
 283 extern void xfs_buf_ioerror_alert(struct xfs_buf *bp, xfs_failaddr_t fa);
 284 void xfs_buf_ioend_fail(struct xfs_buf *);
 285 void xfs_buf_zero(struct xfs_buf *bp, size_t boff, size_t bsize);
 286 void __xfs_buf_mark_corrupt(struct xfs_buf *bp, xfs_failaddr_t fa);
 287 #define xfs_buf_mark_corrupt(bp) __xfs_buf_mark_corrupt((bp), __this_address)
 288
 289 /* Buffer Utility Routines */
 290 extern void *xfs_buf_offset(struct xfs_buf *, size_t);
 291 extern void xfs_buf_stale(struct xfs_buf *bp);
 292
 293 /* Delayed Write Buffer Routines */
 294 extern void xfs_buf_delwri_cancel(struct list_head *);
 295 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
 296 extern int xfs_buf_delwri_submit(struct list_head *);
 297 extern int xfs_buf_delwri_submit_nowait(struct list_head *);
 298 extern int xfs_buf_delwri_pushbuf(struct xfs_buf *, struct list_head *);
 299
 300 /* Buffer Daemon Setup Routines */
 301 extern int xfs_buf_init(void);
 302 extern void xfs_buf_terminate(void);
 303
 304 /*
 305  * These macros use the IO block map rather than b_bn. b_bn is now really
 306  * just for the buffer cache index for cached buffers. As IO does not use b_bn
 307  * anymore, uncached buffers do not use b_bn at all and hence must modify the IO
 308  * map directly. Uncached buffers are not allowed to be discontiguous, so this
 309  * is safe to do.
 310  *
 311  * In future, uncached buffers will pass the block number directly to the io
 312  * request function and hence these macros will go away at that point.
 313  */
 314 #define XFS_BUF_ADDR(bp)                ((bp)->b_maps[0].bm_bn)
 315 #define XFS_BUF_SET_ADDR(bp, bno)       ((bp)->b_maps[0].bm_bn = (xfs_daddr_t)(bno))
 316
 317 void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref);
 318
 319 /*
 320  * If the buffer is already on the LRU, do nothing. Otherwise set the buffer
 321  * up with a reference count of 0 so it will be tossed from the cache when
 322  * released.
 323  */
 324 static inline void xfs_buf_oneshot(struct xfs_buf *bp)
 325 {
 326         if (!list_empty(&bp->b_lru) || atomic_read(&bp->b_lru_ref) > 1)
 327                 return;
 328         atomic_set(&bp->b_lru_ref, 0);
 329 }
 330
 331 static inline int xfs_buf_ispinned(struct xfs_buf *bp)
 332 {
 333         return atomic_read(&bp->b_pin_count);
 334 }
 335
 336 static inline int
 337 xfs_buf_verify_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
 338 {
 339         return xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
 340                                 cksum_offset);
 341 }
 342
 343 static inline void
 344 xfs_buf_update_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
 345 {
 346         xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length),
 347                          cksum_offset);
 348 }
 349
 350 /*
 351  *      Handling of buftargs.
 352  */
 353 extern struct xfs_buftarg *xfs_alloc_buftarg(struct xfs_mount *,
 354                 struct block_device *, struct dax_device *);
 355 extern void xfs_free_buftarg(struct xfs_buftarg *);
 356 extern void xfs_buftarg_wait(struct xfs_buftarg *);
 357 extern void xfs_buftarg_drain(struct xfs_buftarg *);
 358 extern int xfs_setsize_buftarg(struct xfs_buftarg *, unsigned int);
 359
 360 #define xfs_getsize_buftarg(buftarg)    block_size((buftarg)->bt_bdev)
 361 #define xfs_readonly_buftarg(buftarg)   bdev_read_only((buftarg)->bt_bdev)
 362
 363 int xfs_buf_reverify(struct xfs_buf *bp, const struct xfs_buf_ops *ops);
 364 bool xfs_verify_magic(struct xfs_buf *bp, __be32 dmagic);
 365 bool xfs_verify_magic16(struct xfs_buf *bp, __be16 dmagic);
 366
 367 #endif  /* __XFS_BUF_H__ */