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