fs/xfs/libxfs/xfs_btree_mem.c

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright (c) 2021-2024 Oracle.  All Rights Reserved.
   4  * Author: Darrick J. Wong <djwong@kernel.org>
   5  */
   6 #include "xfs.h"
   7 #include "xfs_fs.h"
   8 #include "xfs_shared.h"
   9 #include "xfs_format.h"
  10 #include "xfs_log_format.h"
  11 #include "xfs_trans_resv.h"
  12 #include "xfs_mount.h"
  13 #include "xfs_trans.h"
  14 #include "xfs_btree.h"
  15 #include "xfs_error.h"
  16 #include "xfs_buf_mem.h"
  17 #include "xfs_btree_mem.h"
  18 #include "xfs_ag.h"
  19 #include "xfs_buf_item.h"
  20 #include "xfs_trace.h"
  21
  22 /* Set the root of an in-memory btree. */
  23 void
  24 xfbtree_set_root(
  25         struct xfs_btree_cur            *cur,
  26         const union xfs_btree_ptr       *ptr,
  27         int                             inc)
  28 {
  29         ASSERT(cur->bc_ops->type == XFS_BTREE_TYPE_MEM);
  30
  31         cur->bc_mem.xfbtree->root = *ptr;
  32         cur->bc_mem.xfbtree->nlevels += inc;
  33 }
  34
  35 /* Initialize a pointer from the in-memory btree header. */
  36 void
  37 xfbtree_init_ptr_from_cur(
  38         struct xfs_btree_cur            *cur,
  39         union xfs_btree_ptr             *ptr)
  40 {
  41         ASSERT(cur->bc_ops->type == XFS_BTREE_TYPE_MEM);
  42
  43         *ptr = cur->bc_mem.xfbtree->root;
  44 }
  45
  46 /* Duplicate an in-memory btree cursor. */
  47 struct xfs_btree_cur *
  48 xfbtree_dup_cursor(
  49         struct xfs_btree_cur            *cur)
  50 {
  51         struct xfs_btree_cur            *ncur;
  52
  53         ASSERT(cur->bc_ops->type == XFS_BTREE_TYPE_MEM);
  54
  55         ncur = xfs_btree_alloc_cursor(cur->bc_mp, cur->bc_tp, cur->bc_ops,
  56                         cur->bc_maxlevels, cur->bc_cache);
  57         ncur->bc_flags = cur->bc_flags;
  58         ncur->bc_nlevels = cur->bc_nlevels;
  59         ncur->bc_mem.xfbtree = cur->bc_mem.xfbtree;
  60         if (cur->bc_group)
  61                 ncur->bc_group = xfs_group_hold(cur->bc_group);
  62         return ncur;
  63 }
  64
  65 /* Close the btree xfile and release all resources. */
  66 void
  67 xfbtree_destroy(
  68         struct xfbtree          *xfbt)
  69 {
  70         xfs_buftarg_drain(xfbt->target);
  71 }
  72
  73 /* Compute the number of bytes available for records. */
  74 static inline unsigned int
  75 xfbtree_rec_bytes(
  76         struct xfs_mount                *mp,
  77         const struct xfs_btree_ops      *ops)
  78 {
  79         return XMBUF_BLOCKSIZE - XFS_BTREE_LBLOCK_CRC_LEN;
  80 }
  81
  82 /* Initialize an empty leaf block as the btree root. */
  83 STATIC int
  84 xfbtree_init_leaf_block(
  85         struct xfs_mount                *mp,
  86         struct xfbtree                  *xfbt,
  87         const struct xfs_btree_ops      *ops)
  88 {
  89         struct xfs_buf                  *bp;
  90         xfbno_t                         bno = xfbt->highest_bno++;
  91         int                             error;
  92
  93         error = xfs_buf_get(xfbt->target, xfbno_to_daddr(bno), XFBNO_BBSIZE,
  94                         &bp);
  95         if (error)
  96                 return error;
  97
  98         trace_xfbtree_create_root_buf(xfbt, bp);
  99
 100         bp->b_ops = ops->buf_ops;
 101         xfs_btree_init_buf(mp, bp, ops, 0, 0, xfbt->owner);
 102         xfs_buf_relse(bp);
 103
 104         xfbt->root.l = cpu_to_be64(bno);
 105         return 0;
 106 }
 107
 108 /*
 109  * Create an in-memory btree root that can be used with the given xmbuf.
 110  * Callers must set xfbt->owner.
 111  */
 112 int
 113 xfbtree_init(
 114         struct xfs_mount                *mp,
 115         struct xfbtree                  *xfbt,
 116         struct xfs_buftarg              *btp,
 117         const struct xfs_btree_ops      *ops)
 118 {
 119         unsigned int                    blocklen = xfbtree_rec_bytes(mp, ops);
 120         unsigned int                    keyptr_len;
 121         int                             error;
 122
 123         /* Requires a long-format CRC-format btree */
 124         if (!xfs_has_crc(mp)) {
 125                 ASSERT(xfs_has_crc(mp));
 126                 return -EINVAL;
 127         }
 128         if (ops->ptr_len != XFS_BTREE_LONG_PTR_LEN) {
 129                 ASSERT(ops->ptr_len == XFS_BTREE_LONG_PTR_LEN);
 130                 return -EINVAL;
 131         }
 132
 133         memset(xfbt, 0, sizeof(*xfbt));
 134         xfbt->target = btp;
 135
 136         /* Set up min/maxrecs for this btree. */
 137         keyptr_len = ops->key_len + sizeof(__be64);
 138         xfbt->maxrecs[0] = blocklen / ops->rec_len;
 139         xfbt->maxrecs[1] = blocklen / keyptr_len;
 140         xfbt->minrecs[0] = xfbt->maxrecs[0] / 2;
 141         xfbt->minrecs[1] = xfbt->maxrecs[1] / 2;
 142         xfbt->highest_bno = 0;
 143         xfbt->nlevels = 1;
 144
 145         /* Initialize the empty btree. */
 146         error = xfbtree_init_leaf_block(mp, xfbt, ops);
 147         if (error)
 148                 goto err_freesp;
 149
 150         trace_xfbtree_init(mp, xfbt, ops);
 151
 152         return 0;
 153
 154 err_freesp:
 155         xfs_buftarg_drain(xfbt->target);
 156         return error;
 157 }
 158
 159 /* Allocate a block to our in-memory btree. */
 160 int
 161 xfbtree_alloc_block(
 162         struct xfs_btree_cur            *cur,
 163         const union xfs_btree_ptr       *start,
 164         union xfs_btree_ptr             *new,
 165         int                             *stat)
 166 {
 167         struct xfbtree                  *xfbt = cur->bc_mem.xfbtree;
 168         xfbno_t                         bno = xfbt->highest_bno++;
 169
 170         ASSERT(cur->bc_ops->type == XFS_BTREE_TYPE_MEM);
 171
 172         trace_xfbtree_alloc_block(xfbt, cur, bno);
 173
 174         /* Fail if the block address exceeds the maximum for the buftarg. */
 175         if (!xfbtree_verify_bno(xfbt, bno)) {
 176                 ASSERT(xfbtree_verify_bno(xfbt, bno));
 177                 *stat = 0;
 178                 return 0;
 179         }
 180
 181         new->l = cpu_to_be64(bno);
 182         *stat = 1;
 183         return 0;
 184 }
 185
 186 /* Free a block from our in-memory btree. */
 187 int
 188 xfbtree_free_block(
 189         struct xfs_btree_cur    *cur,
 190         struct xfs_buf          *bp)
 191 {
 192         struct xfbtree          *xfbt = cur->bc_mem.xfbtree;
 193         xfs_daddr_t             daddr = xfs_buf_daddr(bp);
 194         xfbno_t                 bno = xfs_daddr_to_xfbno(daddr);
 195
 196         ASSERT(cur->bc_ops->type == XFS_BTREE_TYPE_MEM);
 197
 198         trace_xfbtree_free_block(xfbt, cur, bno);
 199
 200         if (bno + 1 == xfbt->highest_bno)
 201                 xfbt->highest_bno--;
 202
 203         return 0;
 204 }
 205
 206 /* Return the minimum number of records for a btree block. */
 207 int
 208 xfbtree_get_minrecs(
 209         struct xfs_btree_cur    *cur,
 210         int                     level)
 211 {
 212         struct xfbtree          *xfbt = cur->bc_mem.xfbtree;
 213
 214         return xfbt->minrecs[level != 0];
 215 }
 216
 217 /* Return the maximum number of records for a btree block. */
 218 int
 219 xfbtree_get_maxrecs(
 220         struct xfs_btree_cur    *cur,
 221         int                     level)
 222 {
 223         struct xfbtree          *xfbt = cur->bc_mem.xfbtree;
 224
 225         return xfbt->maxrecs[level != 0];
 226 }
 227
 228 /* If this log item is a buffer item that came from the xfbtree, return it. */
 229 static inline struct xfs_buf *
 230 xfbtree_buf_match(
 231         struct xfbtree                  *xfbt,
 232         const struct xfs_log_item       *lip)
 233 {
 234         const struct xfs_buf_log_item   *bli;
 235         struct xfs_buf                  *bp;
 236
 237         if (lip->li_type != XFS_LI_BUF)
 238                 return NULL;
 239
 240         bli = container_of(lip, struct xfs_buf_log_item, bli_item);
 241         bp = bli->bli_buf;
 242         if (bp->b_target != xfbt->target)
 243                 return NULL;
 244
 245         return bp;
 246 }
 247
 248 /*
 249  * Commit changes to the incore btree immediately by writing all dirty xfbtree
 250  * buffers to the backing xfile.  This detaches all xfbtree buffers from the
 251  * transaction, even on failure.  The buffer locks are dropped between the
 252  * delwri queue and submit, so the caller must synchronize btree access.
 253  *
 254  * Normally we'd let the buffers commit with the transaction and get written to
 255  * the xfile via the log, but online repair stages ephemeral btrees in memory
 256  * and uses the btree_staging functions to write new btrees to disk atomically.
 257  * The in-memory btree (and its backing store) are discarded at the end of the
 258  * repair phase, which means that xfbtree buffers cannot commit with the rest
 259  * of a transaction.
 260  *
 261  * In other words, online repair only needs the transaction to collect buffer
 262  * pointers and to avoid buffer deadlocks, not to guarantee consistency of
 263  * updates.
 264  */
 265 int
 266 xfbtree_trans_commit(
 267         struct xfbtree          *xfbt,
 268         struct xfs_trans        *tp)
 269 {
 270         struct xfs_log_item     *lip, *n;
 271         bool                    tp_dirty = false;
 272         int                     error = 0;
 273
 274         /*
 275          * For each xfbtree buffer attached to the transaction, write the dirty
 276          * buffers to the xfile and release them.
 277          */
 278         list_for_each_entry_safe(lip, n, &tp->t_items, li_trans) {
 279                 struct xfs_buf  *bp = xfbtree_buf_match(xfbt, lip);
 280
 281                 if (!bp) {
 282                         if (test_bit(XFS_LI_DIRTY, &lip->li_flags))
 283                                 tp_dirty |= true;
 284                         continue;
 285                 }
 286
 287                 trace_xfbtree_trans_commit_buf(xfbt, bp);
 288
 289                 xmbuf_trans_bdetach(tp, bp);
 290
 291                 /*
 292                  * If the buffer fails verification, note the failure but
 293                  * continue walking the transaction items so that we remove all
 294                  * ephemeral btree buffers.
 295                  */
 296                 if (!error)
 297                         error = xmbuf_finalize(bp);
 298
 299                 xfs_buf_relse(bp);
 300         }
 301
 302         /*
 303          * Reset the transaction's dirty flag to reflect the dirty state of the
 304          * log items that are still attached.
 305          */
 306         tp->t_flags = (tp->t_flags & ~XFS_TRANS_DIRTY) |
 307                         (tp_dirty ? XFS_TRANS_DIRTY : 0);
 308
 309         return error;
 310 }
 311
 312 /*
 313  * Cancel changes to the incore btree by detaching all the xfbtree buffers.
 314  * Changes are not undone, so callers must not access the btree ever again.
 315  */
 316 void
 317 xfbtree_trans_cancel(
 318         struct xfbtree          *xfbt,
 319         struct xfs_trans        *tp)
 320 {
 321         struct xfs_log_item     *lip, *n;
 322         bool                    tp_dirty = false;
 323
 324         list_for_each_entry_safe(lip, n, &tp->t_items, li_trans) {
 325                 struct xfs_buf  *bp = xfbtree_buf_match(xfbt, lip);
 326
 327                 if (!bp) {
 328                         if (test_bit(XFS_LI_DIRTY, &lip->li_flags))
 329                                 tp_dirty |= true;
 330                         continue;
 331                 }
 332
 333                 trace_xfbtree_trans_cancel_buf(xfbt, bp);
 334
 335                 xmbuf_trans_bdetach(tp, bp);
 336                 xfs_buf_relse(bp);
 337         }
 338
 339         /*
 340          * Reset the transaction's dirty flag to reflect the dirty state of the
 341          * log items that are still attached.
 342          */
 343         tp->t_flags = (tp->t_flags & ~XFS_TRANS_DIRTY) |
 344                         (tp_dirty ? XFS_TRANS_DIRTY : 0);
 345 }