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 extern struct kmem_cache *xfs_buf_cache;
  19
  20 /*
  21  *      Base types
  22  */
  23 struct xfs_buf;
  24
  25 #define XFS_BUF_DADDR_NULL      ((xfs_daddr_t) (-1LL))
  26
  27 #define XBF_READ         (1u << 0) /* buffer intended for reading from device */
  28 #define XBF_WRITE        (1u << 1) /* buffer intended for writing to device */
  29 #define XBF_READ_AHEAD   (1u << 2) /* asynchronous read-ahead */
  30 #define XBF_NO_IOACCT    (1u << 3) /* bypass I/O accounting (non-LRU bufs) */
  31 #define XBF_ASYNC        (1u << 4) /* initiator will not wait for completion */
  32 #define XBF_DONE         (1u << 5) /* all pages in the buffer uptodate */
  33 #define XBF_STALE        (1u << 6) /* buffer has been staled, do not find it */
  34 #define XBF_WRITE_FAIL   (1u << 7) /* async writes have failed on this buffer */
  35
  36 /* buffer type flags for write callbacks */
  37 #define _XBF_INODES      (1u << 16)/* inode buffer */
  38 #define _XBF_DQUOTS      (1u << 17)/* dquot buffer */
  39 #define _XBF_LOGRECOVERY (1u << 18)/* log recovery buffer */
  40
  41 /* flags used only internally */
  42 #define _XBF_PAGES       (1u << 20)/* backed by refcounted pages */
  43 #define _XBF_KMEM        (1u << 21)/* backed by heap memory */
  44 #define _XBF_DELWRI_Q    (1u << 22)/* buffer on a delwri queue */
  45
  46 /* flags used only as arguments to access routines */
  47 #define XBF_INCORE       (1u << 29)/* lookup only, return if found in cache */
  48 #define XBF_TRYLOCK      (1u << 30)/* lock requested, but do not wait */
  49 #define XBF_UNMAPPED     (1u << 31)/* do not map the buffer */
  50
  51
  52 typedef unsigned int xfs_buf_flags_t;
  53
  54 #define XFS_BUF_FLAGS \
  55         { XBF_READ,             "READ" }, \
  56         { XBF_WRITE,            "WRITE" }, \
  57         { XBF_READ_AHEAD,       "READ_AHEAD" }, \
  58         { XBF_NO_IOACCT,        "NO_IOACCT" }, \
  59         { XBF_ASYNC,            "ASYNC" }, \
  60         { XBF_DONE,             "DONE" }, \
  61         { XBF_STALE,            "STALE" }, \
  62         { XBF_WRITE_FAIL,       "WRITE_FAIL" }, \
  63         { _XBF_INODES,          "INODES" }, \
  64         { _XBF_DQUOTS,          "DQUOTS" }, \
  65         { _XBF_LOGRECOVERY,     "LOG_RECOVERY" }, \
  66         { _XBF_PAGES,           "PAGES" }, \
  67         { _XBF_KMEM,            "KMEM" }, \
  68         { _XBF_DELWRI_Q,        "DELWRI_Q" }, \
  69         /* The following interface flags should never be set */ \
  70         { XBF_INCORE,           "INCORE" }, \
  71         { XBF_TRYLOCK,          "TRYLOCK" }, \
  72         { XBF_UNMAPPED,         "UNMAPPED" }
  73
  74 /*
  75  * Internal state flags.
  76  */
  77 #define XFS_BSTATE_DISPOSE       (1 << 0)       /* buffer being discarded */
  78 #define XFS_BSTATE_IN_FLIGHT     (1 << 1)       /* I/O in flight */
  79
  80 /*
  81  * The xfs_buftarg contains 2 notions of "sector size" -
  82  *
  83  * 1) The metadata sector size, which is the minimum unit and
  84  *    alignment of IO which will be performed by metadata operations.
  85  * 2) The device logical sector size
  86  *
  87  * The first is specified at mkfs time, and is stored on-disk in the
  88  * superblock's sb_sectsize.
  89  *
  90  * The latter is derived from the underlying device, and controls direct IO
  91  * alignment constraints.
  92  */
  93 typedef struct xfs_buftarg {
  94         dev_t                   bt_dev;
  95         struct block_device     *bt_bdev;
  96         struct dax_device       *bt_daxdev;
  97         u64                     bt_dax_part_off;
  98         struct xfs_mount        *bt_mount;
  99         unsigned int            bt_meta_sectorsize;
 100         size_t                  bt_meta_sectormask;
 101         size_t                  bt_logical_sectorsize;
 102         size_t                  bt_logical_sectormask;
 103
 104         /* LRU control structures */
 105         struct shrinker         bt_shrinker;
 106         struct list_lru         bt_lru;
 107
 108         struct percpu_counter   bt_io_count;
 109         struct ratelimit_state  bt_ioerror_rl;
 110 } xfs_buftarg_t;
 111
 112 #define XB_PAGES        2
 113
 114 struct xfs_buf_map {
 115         xfs_daddr_t             bm_bn;  /* block number for I/O */
 116         int                     bm_len; /* size of I/O */
 117 };
 118
 119 #define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
 120         struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };
 121
 122 struct xfs_buf_ops {
 123         char *name;
 124         union {
 125                 __be32 magic[2];        /* v4 and v5 on disk magic values */
 126                 __be16 magic16[2];      /* v4 and v5 on disk magic values */
 127         };
 128         void (*verify_read)(struct xfs_buf *);
 129         void (*verify_write)(struct xfs_buf *);
 130         xfs_failaddr_t (*verify_struct)(struct xfs_buf *bp);
 131 };
 132
 133 struct xfs_buf {
 134         /*
 135          * first cacheline holds all the fields needed for an uncontended cache
 136          * hit to be fully processed. The semaphore straddles the cacheline
 137          * boundary, but the counter and lock sits on the first cacheline,
 138          * which is the only bit that is touched if we hit the semaphore
 139          * fast-path on locking.
 140          */
 141         struct rhash_head       b_rhash_head;   /* pag buffer hash node */
 142
 143         xfs_daddr_t             b_rhash_key;    /* buffer cache index */
 144         int                     b_length;       /* size of buffer in BBs */
 145         atomic_t                b_hold;         /* reference count */
 146         atomic_t                b_lru_ref;      /* lru reclaim ref count */
 147         xfs_buf_flags_t         b_flags;        /* status flags */
 148         struct semaphore        b_sema;         /* semaphore for lockables */
 149
 150         /*
 151          * concurrent access to b_lru and b_lru_flags are protected by
 152          * bt_lru_lock and not by b_sema
 153          */
 154         struct list_head        b_lru;          /* lru list */
 155         spinlock_t              b_lock;         /* internal state lock */
 156         unsigned int            b_state;        /* internal state flags */
 157         int                     b_io_error;     /* internal IO error state */
 158         wait_queue_head_t       b_waiters;      /* unpin waiters */
 159         struct list_head        b_list;
 160         struct xfs_perag        *b_pag;         /* contains rbtree root */
 161         struct xfs_mount        *b_mount;
 162         struct xfs_buftarg      *b_target;      /* buffer target (device) */
 163         void                    *b_addr;        /* virtual address of buffer */
 164         struct work_struct      b_ioend_work;
 165         struct completion       b_iowait;       /* queue for I/O waiters */
 166         struct xfs_buf_log_item *b_log_item;
 167         struct list_head        b_li_list;      /* Log items list head */
 168         struct xfs_trans        *b_transp;
 169         struct page             **b_pages;      /* array of page pointers */
 170         struct page             *b_page_array[XB_PAGES]; /* inline pages */
 171         struct xfs_buf_map      *b_maps;        /* compound buffer map */
 172         struct xfs_buf_map      __b_map;        /* inline compound buffer map */
 173         int                     b_map_count;
 174         atomic_t                b_pin_count;    /* pin count */
 175         atomic_t                b_io_remaining; /* #outstanding I/O requests */
 176         unsigned int            b_page_count;   /* size of page array */
 177         unsigned int            b_offset;       /* page offset of b_addr,
 178                                                    only for _XBF_KMEM buffers */
 179         int                     b_error;        /* error code on I/O */
 180
 181         /*
 182          * async write failure retry count. Initialised to zero on the first
 183          * failure, then when it exceeds the maximum configured without a
 184          * success the write is considered to be failed permanently and the
 185          * iodone handler will take appropriate action.
 186          *
 187          * For retry timeouts, we record the jiffie of the first failure. This
 188          * means that we can change the retry timeout for buffers already under
 189          * I/O and thus avoid getting stuck in a retry loop with a long timeout.
 190          *
 191          * last_error is used to ensure that we are getting repeated errors, not
 192          * different errors. e.g. a block device might change ENOSPC to EIO when
 193          * a failure timeout occurs, so we want to re-initialise the error
 194          * retry behaviour appropriately when that happens.
 195          */
 196         int                     b_retries;
 197         unsigned long           b_first_retry_time; /* in jiffies */
 198         int                     b_last_error;
 199
 200         const struct xfs_buf_ops        *b_ops;
 201         struct rcu_head         b_rcu;
 202 };
 203
 204 /* Finding and Reading Buffers */
 205 int xfs_buf_get_map(struct xfs_buftarg *target, struct xfs_buf_map *map,
 206                 int nmaps, xfs_buf_flags_t flags, struct xfs_buf **bpp);
 207 int xfs_buf_read_map(struct xfs_buftarg *target, struct xfs_buf_map *map,
 208                 int nmaps, xfs_buf_flags_t flags, struct xfs_buf **bpp,
 209                 const struct xfs_buf_ops *ops, xfs_failaddr_t fa);
 210 void xfs_buf_readahead_map(struct xfs_buftarg *target,
 211                                struct xfs_buf_map *map, int nmaps,
 212                                const struct xfs_buf_ops *ops);
 213
 214 static inline int
 215 xfs_buf_incore(
 216         struct xfs_buftarg      *target,
 217         xfs_daddr_t             blkno,
 218         size_t                  numblks,
 219         xfs_buf_flags_t         flags,
 220         struct xfs_buf          **bpp)
 221 {
 222         DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
 223
 224         return xfs_buf_get_map(target, &map, 1, XBF_INCORE | flags, bpp);
 225 }
 226
 227 static inline int
 228 xfs_buf_get(
 229         struct xfs_buftarg      *target,
 230         xfs_daddr_t             blkno,
 231         size_t                  numblks,
 232         struct xfs_buf          **bpp)
 233 {
 234         DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
 235
 236         return xfs_buf_get_map(target, &map, 1, 0, bpp);
 237 }
 238
 239 static inline int
 240 xfs_buf_read(
 241         struct xfs_buftarg      *target,
 242         xfs_daddr_t             blkno,
 243         size_t                  numblks,
 244         xfs_buf_flags_t         flags,
 245         struct xfs_buf          **bpp,
 246         const struct xfs_buf_ops *ops)
 247 {
 248         DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
 249
 250         return xfs_buf_read_map(target, &map, 1, flags, bpp, ops,
 251                         __builtin_return_address(0));
 252 }
 253
 254 static inline void
 255 xfs_buf_readahead(
 256         struct xfs_buftarg      *target,
 257         xfs_daddr_t             blkno,
 258         size_t                  numblks,
 259         const struct xfs_buf_ops *ops)
 260 {
 261         DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
 262         return xfs_buf_readahead_map(target, &map, 1, ops);
 263 }
 264
 265 int xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
 266                 xfs_buf_flags_t flags, struct xfs_buf **bpp);
 267 int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr,
 268                 size_t numblks, xfs_buf_flags_t flags, struct xfs_buf **bpp,
 269                 const struct xfs_buf_ops *ops);
 270 int _xfs_buf_read(struct xfs_buf *bp, xfs_buf_flags_t flags);
 271 void xfs_buf_hold(struct xfs_buf *bp);
 272
 273 /* Releasing Buffers */
 274 extern void xfs_buf_rele(struct xfs_buf *);
 275
 276 /* Locking and Unlocking Buffers */
 277 extern int xfs_buf_trylock(struct xfs_buf *);
 278 extern void xfs_buf_lock(struct xfs_buf *);
 279 extern void xfs_buf_unlock(struct xfs_buf *);
 280 #define xfs_buf_islocked(bp) \
 281         ((bp)->b_sema.count <= 0)
 282
 283 static inline void xfs_buf_relse(struct xfs_buf *bp)
 284 {
 285         xfs_buf_unlock(bp);
 286         xfs_buf_rele(bp);
 287 }
 288
 289 /* Buffer Read and Write Routines */
 290 extern int xfs_bwrite(struct xfs_buf *bp);
 291
 292 extern void __xfs_buf_ioerror(struct xfs_buf *bp, int error,
 293                 xfs_failaddr_t failaddr);
 294 #define xfs_buf_ioerror(bp, err) __xfs_buf_ioerror((bp), (err), __this_address)
 295 extern void xfs_buf_ioerror_alert(struct xfs_buf *bp, xfs_failaddr_t fa);
 296 void xfs_buf_ioend_fail(struct xfs_buf *);
 297 void xfs_buf_zero(struct xfs_buf *bp, size_t boff, size_t bsize);
 298 void __xfs_buf_mark_corrupt(struct xfs_buf *bp, xfs_failaddr_t fa);
 299 #define xfs_buf_mark_corrupt(bp) __xfs_buf_mark_corrupt((bp), __this_address)
 300
 301 /* Buffer Utility Routines */
 302 extern void *xfs_buf_offset(struct xfs_buf *, size_t);
 303 extern void xfs_buf_stale(struct xfs_buf *bp);
 304
 305 /* Delayed Write Buffer Routines */
 306 extern void xfs_buf_delwri_cancel(struct list_head *);
 307 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
 308 extern int xfs_buf_delwri_submit(struct list_head *);
 309 extern int xfs_buf_delwri_submit_nowait(struct list_head *);
 310 extern int xfs_buf_delwri_pushbuf(struct xfs_buf *, struct list_head *);
 311
 312 static inline xfs_daddr_t xfs_buf_daddr(struct xfs_buf *bp)
 313 {
 314         return bp->b_maps[0].bm_bn;
 315 }
 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 struct xfs_buftarg *xfs_alloc_buftarg(struct xfs_mount *mp,
 354                 struct block_device *bdev);
 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__ */