fs/xfs/xfs_discard.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2010 Red Hat, Inc.
   4  * All Rights Reserved.
   5  */
   6 #include "xfs.h"
   7 #include "xfs_shared.h"
   8 #include "xfs_format.h"
   9 #include "xfs_log_format.h"
  10 #include "xfs_trans_resv.h"
  11 #include "xfs_sb.h"
  12 #include "xfs_mount.h"
  13 #include "xfs_btree.h"
  14 #include "xfs_alloc_btree.h"
  15 #include "xfs_alloc.h"
  16 #include "xfs_discard.h"
  17 #include "xfs_error.h"
  18 #include "xfs_extent_busy.h"
  19 #include "xfs_trace.h"
  20 #include "xfs_log.h"
  21
  22 STATIC int
  23 xfs_trim_extents(
  24         struct xfs_mount        *mp,
  25         xfs_agnumber_t          agno,
  26         xfs_daddr_t             start,
  27         xfs_daddr_t             end,
  28         xfs_daddr_t             minlen,
  29         uint64_t                *blocks_trimmed)
  30 {
  31         struct block_device     *bdev = mp->m_ddev_targp->bt_bdev;
  32         struct xfs_btree_cur    *cur;
  33         struct xfs_buf          *agbp;
  34         struct xfs_perag        *pag;
  35         int                     error;
  36         int                     i;
  37
  38         pag = xfs_perag_get(mp, agno);
  39
  40         /*
  41          * Force out the log.  This means any transactions that might have freed
  42          * space before we take the AGF buffer lock are now on disk, and the
  43          * volatile disk cache is flushed.
  44          */
  45         xfs_log_force(mp, XFS_LOG_SYNC);
  46
  47         error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
  48         if (error)
  49                 goto out_put_perag;
  50
  51         cur = xfs_allocbt_init_cursor(mp, NULL, agbp, agno, XFS_BTNUM_CNT);
  52
  53         /*
  54          * Look up the longest btree in the AGF and start with it.
  55          */
  56         error = xfs_alloc_lookup_ge(cur, 0,
  57                             be32_to_cpu(XFS_BUF_TO_AGF(agbp)->agf_longest), &i);
  58         if (error)
  59                 goto out_del_cursor;
  60
  61         /*
  62          * Loop until we are done with all extents that are large
  63          * enough to be worth discarding.
  64          */
  65         while (i) {
  66                 xfs_agblock_t   fbno;
  67                 xfs_extlen_t    flen;
  68                 xfs_daddr_t     dbno;
  69                 xfs_extlen_t    dlen;
  70
  71                 error = xfs_alloc_get_rec(cur, &fbno, &flen, &i);
  72                 if (error)
  73                         goto out_del_cursor;
  74                 if (XFS_IS_CORRUPT(mp, i != 1)) {
  75                         error = -EFSCORRUPTED;
  76                         goto out_del_cursor;
  77                 }
  78                 ASSERT(flen <= be32_to_cpu(XFS_BUF_TO_AGF(agbp)->agf_longest));
  79
  80                 /*
  81                  * use daddr format for all range/len calculations as that is
  82                  * the format the range/len variables are supplied in by
  83                  * userspace.
  84                  */
  85                 dbno = XFS_AGB_TO_DADDR(mp, agno, fbno);
  86                 dlen = XFS_FSB_TO_BB(mp, flen);
  87
  88                 /*
  89                  * Too small?  Give up.
  90                  */
  91                 if (dlen < minlen) {
  92                         trace_xfs_discard_toosmall(mp, agno, fbno, flen);
  93                         goto out_del_cursor;
  94                 }
  95
  96                 /*
  97                  * If the extent is entirely outside of the range we are
  98                  * supposed to discard skip it.  Do not bother to trim
  99                  * down partially overlapping ranges for now.
 100                  */
 101                 if (dbno + dlen < start || dbno > end) {
 102                         trace_xfs_discard_exclude(mp, agno, fbno, flen);
 103                         goto next_extent;
 104                 }
 105
 106                 /*
 107                  * If any blocks in the range are still busy, skip the
 108                  * discard and try again the next time.
 109                  */
 110                 if (xfs_extent_busy_search(mp, agno, fbno, flen)) {
 111                         trace_xfs_discard_busy(mp, agno, fbno, flen);
 112                         goto next_extent;
 113                 }
 114
 115                 trace_xfs_discard_extent(mp, agno, fbno, flen);
 116                 error = blkdev_issue_discard(bdev, dbno, dlen, GFP_NOFS, 0);
 117                 if (error)
 118                         goto out_del_cursor;
 119                 *blocks_trimmed += flen;
 120
 121 next_extent:
 122                 error = xfs_btree_decrement(cur, 0, &i);
 123                 if (error)
 124                         goto out_del_cursor;
 125
 126                 if (fatal_signal_pending(current)) {
 127                         error = -ERESTARTSYS;
 128                         goto out_del_cursor;
 129                 }
 130         }
 131
 132 out_del_cursor:
 133         xfs_btree_del_cursor(cur, error);
 134         xfs_buf_relse(agbp);
 135 out_put_perag:
 136         xfs_perag_put(pag);
 137         return error;
 138 }
 139
 140 /*
 141  * trim a range of the filesystem.
 142  *
 143  * Note: the parameters passed from userspace are byte ranges into the
 144  * filesystem which does not match to the format we use for filesystem block
 145  * addressing. FSB addressing is sparse (AGNO|AGBNO), while the incoming format
 146  * is a linear address range. Hence we need to use DADDR based conversions and
 147  * comparisons for determining the correct offset and regions to trim.
 148  */
 149 int
 150 xfs_ioc_trim(
 151         struct xfs_mount                *mp,
 152         struct fstrim_range __user      *urange)
 153 {
 154         struct request_queue    *q = bdev_get_queue(mp->m_ddev_targp->bt_bdev);
 155         unsigned int            granularity = q->limits.discard_granularity;
 156         struct fstrim_range     range;
 157         xfs_daddr_t             start, end, minlen;
 158         xfs_agnumber_t          start_agno, end_agno, agno;
 159         uint64_t                blocks_trimmed = 0;
 160         int                     error, last_error = 0;
 161
 162         if (!capable(CAP_SYS_ADMIN))
 163                 return -EPERM;
 164         if (!blk_queue_discard(q))
 165                 return -EOPNOTSUPP;
 166
 167         /*
 168          * We haven't recovered the log, so we cannot use our bnobt-guided
 169          * storage zapping commands.
 170          */
 171         if (mp->m_flags & XFS_MOUNT_NORECOVERY)
 172                 return -EROFS;
 173
 174         if (copy_from_user(&range, urange, sizeof(range)))
 175                 return -EFAULT;
 176
 177         range.minlen = max_t(u64, granularity, range.minlen);
 178         minlen = BTOBB(range.minlen);
 179         /*
 180          * Truncating down the len isn't actually quite correct, but using
 181          * BBTOB would mean we trivially get overflows for values
 182          * of ULLONG_MAX or slightly lower.  And ULLONG_MAX is the default
 183          * used by the fstrim application.  In the end it really doesn't
 184          * matter as trimming blocks is an advisory interface.
 185          */
 186         if (range.start >= XFS_FSB_TO_B(mp, mp->m_sb.sb_dblocks) ||
 187             range.minlen > XFS_FSB_TO_B(mp, mp->m_ag_max_usable) ||
 188             range.len < mp->m_sb.sb_blocksize)
 189                 return -EINVAL;
 190
 191         start = BTOBB(range.start);
 192         end = start + BTOBBT(range.len) - 1;
 193
 194         if (end > XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) - 1)
 195                 end = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)- 1;
 196
 197         start_agno = xfs_daddr_to_agno(mp, start);
 198         end_agno = xfs_daddr_to_agno(mp, end);
 199
 200         for (agno = start_agno; agno <= end_agno; agno++) {
 201                 error = xfs_trim_extents(mp, agno, start, end, minlen,
 202                                           &blocks_trimmed);
 203                 if (error) {
 204                         last_error = error;
 205                         if (error == -ERESTARTSYS)
 206                                 break;
 207                 }
 208         }
 209
 210         if (last_error)
 211                 return last_error;
 212
 213         range.len = XFS_FSB_TO_B(mp, blocks_trimmed);
 214         if (copy_to_user(urange, &range, sizeof(range)))
 215                 return -EFAULT;
 216         return 0;
 217 }