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 /*
  48  * Online fsck is scanning the buffer cache for live buffers.  Do not warn
  49  * about length mismatches during lookups and do not return stale buffers.
  50  */
  51 #define XBF_LIVESCAN     (1u << 28)
  52 #define XBF_INCORE       (1u << 29)/* lookup only, return if found in cache */
  53 #define XBF_TRYLOCK      (1u << 30)/* lock requested, but do not wait */
  54 #define XBF_UNMAPPED     (1u << 31)/* do not map the buffer */
  55
  56
  57 typedef unsigned int xfs_buf_flags_t;
  58
  59 #define XFS_BUF_FLAGS \
  60         { XBF_READ,             "READ" }, \
  61         { XBF_WRITE,            "WRITE" }, \
  62         { XBF_READ_AHEAD,       "READ_AHEAD" }, \
  63         { XBF_NO_IOACCT,        "NO_IOACCT" }, \
  64         { XBF_ASYNC,            "ASYNC" }, \
  65         { XBF_DONE,             "DONE" }, \
  66         { XBF_STALE,            "STALE" }, \
  67         { XBF_WRITE_FAIL,       "WRITE_FAIL" }, \
  68         { _XBF_INODES,          "INODES" }, \
  69         { _XBF_DQUOTS,          "DQUOTS" }, \
  70         { _XBF_LOGRECOVERY,     "LOG_RECOVERY" }, \
  71         { _XBF_PAGES,           "PAGES" }, \
  72         { _XBF_KMEM,            "KMEM" }, \
  73         { _XBF_DELWRI_Q,        "DELWRI_Q" }, \
  74         /* The following interface flags should never be set */ \
  75         { XBF_LIVESCAN,         "LIVESCAN" }, \
  76         { XBF_INCORE,           "INCORE" }, \
  77         { XBF_TRYLOCK,          "TRYLOCK" }, \
  78         { XBF_UNMAPPED,         "UNMAPPED" }
  79
  80 /*
  81  * Internal state flags.
  82  */
  83 #define XFS_BSTATE_DISPOSE       (1 << 0)       /* buffer being discarded */
  84 #define XFS_BSTATE_IN_FLIGHT     (1 << 1)       /* I/O in flight */
  85
  86 struct xfs_buf_cache {
  87         spinlock_t              bc_lock;
  88         struct rhashtable       bc_hash;
  89 };
  90
  91 int xfs_buf_cache_init(struct xfs_buf_cache *bch);
  92 void xfs_buf_cache_destroy(struct xfs_buf_cache *bch);
  93
  94 /*
  95  * The xfs_buftarg contains 2 notions of "sector size" -
  96  *
  97  * 1) The metadata sector size, which is the minimum unit and
  98  *    alignment of IO which will be performed by metadata operations.
  99  * 2) The device logical sector size
 100  *
 101  * The first is specified at mkfs time, and is stored on-disk in the
 102  * superblock's sb_sectsize.
 103  *
 104  * The latter is derived from the underlying device, and controls direct IO
 105  * alignment constraints.
 106  */
 107 struct xfs_buftarg {
 108         dev_t                   bt_dev;
 109         struct file             *bt_bdev_file;
 110         struct block_device     *bt_bdev;
 111         struct dax_device       *bt_daxdev;
 112         struct file             *bt_file;
 113         u64                     bt_dax_part_off;
 114         struct xfs_mount        *bt_mount;
 115         unsigned int            bt_meta_sectorsize;
 116         size_t                  bt_meta_sectormask;
 117         size_t                  bt_logical_sectorsize;
 118         size_t                  bt_logical_sectormask;
 119
 120         /* LRU control structures */
 121         struct shrinker         *bt_shrinker;
 122         struct list_lru         bt_lru;
 123
 124         struct percpu_counter   bt_io_count;
 125         struct ratelimit_state  bt_ioerror_rl;
 126
 127         /* built-in cache, if we're not using the perag one */
 128         struct xfs_buf_cache    bt_cache[];
 129 };
 130
 131 #define XB_PAGES        2
 132
 133 struct xfs_buf_map {
 134         xfs_daddr_t             bm_bn;  /* block number for I/O */
 135         int                     bm_len; /* size of I/O */
 136         unsigned int            bm_flags;
 137 };
 138
 139 /*
 140  * Online fsck is scanning the buffer cache for live buffers.  Do not warn
 141  * about length mismatches during lookups and do not return stale buffers.
 142  */
 143 #define XBM_LIVESCAN            (1U << 0)
 144
 145 #define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
 146         struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };
 147
 148 struct xfs_buf_ops {
 149         char *name;
 150         union {
 151                 __be32 magic[2];        /* v4 and v5 on disk magic values */
 152                 __be16 magic16[2];      /* v4 and v5 on disk magic values */
 153         };
 154         void (*verify_read)(struct xfs_buf *);
 155         void (*verify_write)(struct xfs_buf *);
 156         xfs_failaddr_t (*verify_struct)(struct xfs_buf *bp);
 157 };
 158
 159 struct xfs_buf {
 160         /*
 161          * first cacheline holds all the fields needed for an uncontended cache
 162          * hit to be fully processed. The semaphore straddles the cacheline
 163          * boundary, but the counter and lock sits on the first cacheline,
 164          * which is the only bit that is touched if we hit the semaphore
 165          * fast-path on locking.
 166          */
 167         struct rhash_head       b_rhash_head;   /* pag buffer hash node */
 168
 169         xfs_daddr_t             b_rhash_key;    /* buffer cache index */
 170         int                     b_length;       /* size of buffer in BBs */
 171         atomic_t                b_hold;         /* reference count */
 172         atomic_t                b_lru_ref;      /* lru reclaim ref count */
 173         xfs_buf_flags_t         b_flags;        /* status flags */
 174         struct semaphore        b_sema;         /* semaphore for lockables */
 175
 176         /*
 177          * concurrent access to b_lru and b_lru_flags are protected by
 178          * bt_lru_lock and not by b_sema
 179          */
 180         struct list_head        b_lru;          /* lru list */
 181         spinlock_t              b_lock;         /* internal state lock */
 182         unsigned int            b_state;        /* internal state flags */
 183         int                     b_io_error;     /* internal IO error state */
 184         wait_queue_head_t       b_waiters;      /* unpin waiters */
 185         struct list_head        b_list;
 186         struct xfs_perag        *b_pag;         /* contains rbtree root */
 187         struct xfs_mount        *b_mount;
 188         struct xfs_buftarg      *b_target;      /* buffer target (device) */
 189         void                    *b_addr;        /* virtual address of buffer */
 190         struct work_struct      b_ioend_work;
 191         struct completion       b_iowait;       /* queue for I/O waiters */
 192         struct xfs_buf_log_item *b_log_item;
 193         struct list_head        b_li_list;      /* Log items list head */
 194         struct xfs_trans        *b_transp;
 195         struct page             **b_pages;      /* array of page pointers */
 196         struct page             *b_page_array[XB_PAGES]; /* inline pages */
 197         struct xfs_buf_map      *b_maps;        /* compound buffer map */
 198         struct xfs_buf_map      __b_map;        /* inline compound buffer map */
 199         int                     b_map_count;
 200         atomic_t                b_pin_count;    /* pin count */
 201         atomic_t                b_io_remaining; /* #outstanding I/O requests */
 202         unsigned int            b_page_count;   /* size of page array */
 203         unsigned int            b_offset;       /* page offset of b_addr,
 204                                                    only for _XBF_KMEM buffers */
 205         int                     b_error;        /* error code on I/O */
 206
 207         /*
 208          * async write failure retry count. Initialised to zero on the first
 209          * failure, then when it exceeds the maximum configured without a
 210          * success the write is considered to be failed permanently and the
 211          * iodone handler will take appropriate action.
 212          *
 213          * For retry timeouts, we record the jiffy of the first failure. This
 214          * means that we can change the retry timeout for buffers already under
 215          * I/O and thus avoid getting stuck in a retry loop with a long timeout.
 216          *
 217          * last_error is used to ensure that we are getting repeated errors, not
 218          * different errors. e.g. a block device might change ENOSPC to EIO when
 219          * a failure timeout occurs, so we want to re-initialise the error
 220          * retry behaviour appropriately when that happens.
 221          */
 222         int                     b_retries;
 223         unsigned long           b_first_retry_time; /* in jiffies */
 224         int                     b_last_error;
 225
 226         const struct xfs_buf_ops        *b_ops;
 227         struct rcu_head         b_rcu;
 228 };
 229
 230 /* Finding and Reading Buffers */
 231 int xfs_buf_get_map(struct xfs_buftarg *target, struct xfs_buf_map *map,
 232                 int nmaps, xfs_buf_flags_t flags, struct xfs_buf **bpp);
 233 int xfs_buf_read_map(struct xfs_buftarg *target, struct xfs_buf_map *map,
 234                 int nmaps, xfs_buf_flags_t flags, struct xfs_buf **bpp,
 235                 const struct xfs_buf_ops *ops, xfs_failaddr_t fa);
 236 void xfs_buf_readahead_map(struct xfs_buftarg *target,
 237                                struct xfs_buf_map *map, int nmaps,
 238                                const struct xfs_buf_ops *ops);
 239
 240 static inline int
 241 xfs_buf_incore(
 242         struct xfs_buftarg      *target,
 243         xfs_daddr_t             blkno,
 244         size_t                  numblks,
 245         xfs_buf_flags_t         flags,
 246         struct xfs_buf          **bpp)
 247 {
 248         DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
 249
 250         return xfs_buf_get_map(target, &map, 1, XBF_INCORE | flags, bpp);
 251 }
 252
 253 static inline int
 254 xfs_buf_get(
 255         struct xfs_buftarg      *target,
 256         xfs_daddr_t             blkno,
 257         size_t                  numblks,
 258         struct xfs_buf          **bpp)
 259 {
 260         DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
 261
 262         return xfs_buf_get_map(target, &map, 1, 0, bpp);
 263 }
 264
 265 static inline int
 266 xfs_buf_read(
 267         struct xfs_buftarg      *target,
 268         xfs_daddr_t             blkno,
 269         size_t                  numblks,
 270         xfs_buf_flags_t         flags,
 271         struct xfs_buf          **bpp,
 272         const struct xfs_buf_ops *ops)
 273 {
 274         DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
 275
 276         return xfs_buf_read_map(target, &map, 1, flags, bpp, ops,
 277                         __builtin_return_address(0));
 278 }
 279
 280 static inline void
 281 xfs_buf_readahead(
 282         struct xfs_buftarg      *target,
 283         xfs_daddr_t             blkno,
 284         size_t                  numblks,
 285         const struct xfs_buf_ops *ops)
 286 {
 287         DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
 288         return xfs_buf_readahead_map(target, &map, 1, ops);
 289 }
 290
 291 int xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
 292                 xfs_buf_flags_t flags, struct xfs_buf **bpp);
 293 int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr,
 294                 size_t numblks, xfs_buf_flags_t flags, struct xfs_buf **bpp,
 295                 const struct xfs_buf_ops *ops);
 296 int _xfs_buf_read(struct xfs_buf *bp, xfs_buf_flags_t flags);
 297 void xfs_buf_hold(struct xfs_buf *bp);
 298
 299 /* Releasing Buffers */
 300 extern void xfs_buf_rele(struct xfs_buf *);
 301
 302 /* Locking and Unlocking Buffers */
 303 extern int xfs_buf_trylock(struct xfs_buf *);
 304 extern void xfs_buf_lock(struct xfs_buf *);
 305 extern void xfs_buf_unlock(struct xfs_buf *);
 306 #define xfs_buf_islocked(bp) \
 307         ((bp)->b_sema.count <= 0)
 308
 309 static inline void xfs_buf_relse(struct xfs_buf *bp)
 310 {
 311         xfs_buf_unlock(bp);
 312         xfs_buf_rele(bp);
 313 }
 314
 315 /* Buffer Read and Write Routines */
 316 extern int xfs_bwrite(struct xfs_buf *bp);
 317
 318 extern void __xfs_buf_ioerror(struct xfs_buf *bp, int error,
 319                 xfs_failaddr_t failaddr);
 320 #define xfs_buf_ioerror(bp, err) __xfs_buf_ioerror((bp), (err), __this_address)
 321 extern void xfs_buf_ioerror_alert(struct xfs_buf *bp, xfs_failaddr_t fa);
 322 void xfs_buf_ioend_fail(struct xfs_buf *);
 323 void xfs_buf_zero(struct xfs_buf *bp, size_t boff, size_t bsize);
 324 void __xfs_buf_mark_corrupt(struct xfs_buf *bp, xfs_failaddr_t fa);
 325 #define xfs_buf_mark_corrupt(bp) __xfs_buf_mark_corrupt((bp), __this_address)
 326
 327 /* Buffer Utility Routines */
 328 extern void *xfs_buf_offset(struct xfs_buf *, size_t);
 329 extern void xfs_buf_stale(struct xfs_buf *bp);
 330
 331 /* Delayed Write Buffer Routines */
 332 extern void xfs_buf_delwri_cancel(struct list_head *);
 333 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
 334 void xfs_buf_delwri_queue_here(struct xfs_buf *bp, struct list_head *bl);
 335 extern int xfs_buf_delwri_submit(struct list_head *);
 336 extern int xfs_buf_delwri_submit_nowait(struct list_head *);
 337 extern int xfs_buf_delwri_pushbuf(struct xfs_buf *, struct list_head *);
 338
 339 static inline xfs_daddr_t xfs_buf_daddr(struct xfs_buf *bp)
 340 {
 341         return bp->b_maps[0].bm_bn;
 342 }
 343
 344 void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref);
 345
 346 /*
 347  * If the buffer is already on the LRU, do nothing. Otherwise set the buffer
 348  * up with a reference count of 0 so it will be tossed from the cache when
 349  * released.
 350  */
 351 static inline void xfs_buf_oneshot(struct xfs_buf *bp)
 352 {
 353         if (!list_empty(&bp->b_lru) || atomic_read(&bp->b_lru_ref) > 1)
 354                 return;
 355         atomic_set(&bp->b_lru_ref, 0);
 356 }
 357
 358 static inline int xfs_buf_ispinned(struct xfs_buf *bp)
 359 {
 360         return atomic_read(&bp->b_pin_count);
 361 }
 362
 363 static inline int
 364 xfs_buf_verify_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
 365 {
 366         return xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
 367                                 cksum_offset);
 368 }
 369
 370 static inline void
 371 xfs_buf_update_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
 372 {
 373         xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length),
 374                          cksum_offset);
 375 }
 376
 377 /*
 378  *      Handling of buftargs.
 379  */
 380 struct xfs_buftarg *xfs_alloc_buftarg(struct xfs_mount *mp,
 381                 struct file *bdev_file);
 382 extern void xfs_free_buftarg(struct xfs_buftarg *);
 383 extern void xfs_buftarg_wait(struct xfs_buftarg *);
 384 extern void xfs_buftarg_drain(struct xfs_buftarg *);
 385 extern int xfs_setsize_buftarg(struct xfs_buftarg *, unsigned int);
 386
 387 #define xfs_getsize_buftarg(buftarg)    block_size((buftarg)->bt_bdev)
 388 #define xfs_readonly_buftarg(buftarg)   bdev_read_only((buftarg)->bt_bdev)
 389
 390 int xfs_buf_reverify(struct xfs_buf *bp, const struct xfs_buf_ops *ops);
 391 bool xfs_verify_magic(struct xfs_buf *bp, __be32 dmagic);
 392 bool xfs_verify_magic16(struct xfs_buf *bp, __be16 dmagic);
 393
 394 /* for xfs_buf_mem.c only: */
 395 int xfs_init_buftarg(struct xfs_buftarg *btp, size_t logical_sectorsize,
 396                 const char *descr);
 397 void xfs_destroy_buftarg(struct xfs_buftarg *btp);
 398
 399 #endif  /* __XFS_BUF_H__ */