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_agf          *agf;
  35         struct xfs_perag        *pag;
  36         int                     error;
  37         int                     i;
  38
  39         pag = xfs_perag_get(mp, agno);
  40
  41         /*
  42          * Force out the log.  This means any transactions that might have freed
  43          * space before we take the AGF buffer lock are now on disk, and the
  44          * volatile disk cache is flushed.
  45          */
  46         xfs_log_force(mp, XFS_LOG_SYNC);
  47
  48         error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
  49         if (error)
  50                 goto out_put_perag;
  51         agf = agbp->b_addr;
  52
  53         cur = xfs_allocbt_init_cursor(mp, NULL, agbp, agno, XFS_BTNUM_CNT);
  54
  55         /*
  56          * Look up the longest btree in the AGF and start with it.
  57          */
  58         error = xfs_alloc_lookup_ge(cur, 0, be32_to_cpu(agf->agf_longest), &i);
  59         if (error)
  60                 goto out_del_cursor;
  61
  62         /*
  63          * Loop until we are done with all extents that are large
  64          * enough to be worth discarding.
  65          */
  66         while (i) {
  67                 xfs_agblock_t   fbno;
  68                 xfs_extlen_t    flen;
  69                 xfs_daddr_t     dbno;
  70                 xfs_extlen_t    dlen;
  71
  72                 error = xfs_alloc_get_rec(cur, &fbno, &flen, &i);
  73                 if (error)
  74                         goto out_del_cursor;
  75                 if (XFS_IS_CORRUPT(mp, i != 1)) {
  76                         error = -EFSCORRUPTED;
  77                         goto out_del_cursor;
  78                 }
  79                 ASSERT(flen <= be32_to_cpu(agf->agf_longest));
  80
  81                 /*
  82                  * use daddr format for all range/len calculations as that is
  83                  * the format the range/len variables are supplied in by
  84                  * userspace.
  85                  */
  86                 dbno = XFS_AGB_TO_DADDR(mp, agno, fbno);
  87                 dlen = XFS_FSB_TO_BB(mp, flen);
  88
  89                 /*
  90                  * Too small?  Give up.
  91                  */
  92                 if (dlen < minlen) {
  93                         trace_xfs_discard_toosmall(mp, agno, fbno, flen);
  94                         goto out_del_cursor;
  95                 }
  96
  97                 /*
  98                  * If the extent is entirely outside of the range we are
  99                  * supposed to discard skip it.  Do not bother to trim
 100                  * down partially overlapping ranges for now.
 101                  */
 102                 if (dbno + dlen < start || dbno > end) {
 103                         trace_xfs_discard_exclude(mp, agno, fbno, flen);
 104                         goto next_extent;
 105                 }
 106
 107                 /*
 108                  * If any blocks in the range are still busy, skip the
 109                  * discard and try again the next time.
 110                  */
 111                 if (xfs_extent_busy_search(mp, agno, fbno, flen)) {
 112                         trace_xfs_discard_busy(mp, agno, fbno, flen);
 113                         goto next_extent;
 114                 }
 115
 116                 trace_xfs_discard_extent(mp, agno, fbno, flen);
 117                 error = blkdev_issue_discard(bdev, dbno, dlen, GFP_NOFS, 0);
 118                 if (error)
 119                         goto out_del_cursor;
 120                 *blocks_trimmed += flen;
 121
 122 next_extent:
 123                 error = xfs_btree_decrement(cur, 0, &i);
 124                 if (error)
 125                         goto out_del_cursor;
 126
 127                 if (fatal_signal_pending(current)) {
 128                         error = -ERESTARTSYS;
 129                         goto out_del_cursor;
 130                 }
 131         }
 132
 133 out_del_cursor:
 134         xfs_btree_del_cursor(cur, error);
 135         xfs_buf_relse(agbp);
 136 out_put_perag:
 137         xfs_perag_put(pag);
 138         return error;
 139 }
 140
 141 /*
 142  * trim a range of the filesystem.
 143  *
 144  * Note: the parameters passed from userspace are byte ranges into the
 145  * filesystem which does not match to the format we use for filesystem block
 146  * addressing. FSB addressing is sparse (AGNO|AGBNO), while the incoming format
 147  * is a linear address range. Hence we need to use DADDR based conversions and
 148  * comparisons for determining the correct offset and regions to trim.
 149  */
 150 int
 151 xfs_ioc_trim(
 152         struct xfs_mount                *mp,
 153         struct fstrim_range __user      *urange)
 154 {
 155         struct request_queue    *q = bdev_get_queue(mp->m_ddev_targp->bt_bdev);
 156         unsigned int            granularity = q->limits.discard_granularity;
 157         struct fstrim_range     range;
 158         xfs_daddr_t             start, end, minlen;
 159         xfs_agnumber_t          start_agno, end_agno, agno;
 160         uint64_t                blocks_trimmed = 0;
 161         int                     error, last_error = 0;
 162
 163         if (!capable(CAP_SYS_ADMIN))
 164                 return -EPERM;
 165         if (!blk_queue_discard(q))
 166                 return -EOPNOTSUPP;
 167
 168         /*
 169          * We haven't recovered the log, so we cannot use our bnobt-guided
 170          * storage zapping commands.
 171          */
 172         if (mp->m_flags & XFS_MOUNT_NORECOVERY)
 173                 return -EROFS;
 174
 175         if (copy_from_user(&range, urange, sizeof(range)))
 176                 return -EFAULT;
 177
 178         range.minlen = max_t(u64, granularity, range.minlen);
 179         minlen = BTOBB(range.minlen);
 180         /*
 181          * Truncating down the len isn't actually quite correct, but using
 182          * BBTOB would mean we trivially get overflows for values
 183          * of ULLONG_MAX or slightly lower.  And ULLONG_MAX is the default
 184          * used by the fstrim application.  In the end it really doesn't
 185          * matter as trimming blocks is an advisory interface.
 186          */
 187         if (range.start >= XFS_FSB_TO_B(mp, mp->m_sb.sb_dblocks) ||
 188             range.minlen > XFS_FSB_TO_B(mp, mp->m_ag_max_usable) ||
 189             range.len < mp->m_sb.sb_blocksize)
 190                 return -EINVAL;
 191
 192         start = BTOBB(range.start);
 193         end = start + BTOBBT(range.len) - 1;
 194
 195         if (end > XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) - 1)
 196                 end = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)- 1;
 197
 198         start_agno = xfs_daddr_to_agno(mp, start);
 199         end_agno = xfs_daddr_to_agno(mp, end);
 200
 201         for (agno = start_agno; agno <= end_agno; agno++) {
 202                 error = xfs_trim_extents(mp, agno, start, end, minlen,
 203                                           &blocks_trimmed);
 204                 if (error) {
 205                         last_error = error;
 206                         if (error == -ERESTARTSYS)
 207                                 break;
 208                 }
 209         }
 210
 211         if (last_error)
 212                 return last_error;
 213
 214         range.len = XFS_FSB_TO_B(mp, blocks_trimmed);
 215         if (copy_to_user(urange, &range, sizeof(range)))
 216                 return -EFAULT;
 217         return 0;
 218 }