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_format.h"
   8 #include "xfs_log_format.h"
   9 #include "xfs_trans_resv.h"
  10 #include "xfs_sb.h"
  11 #include "xfs_mount.h"
  12 #include "xfs_quota.h"
  13 #include "xfs_inode.h"
  14 #include "xfs_btree.h"
  15 #include "xfs_alloc_btree.h"
  16 #include "xfs_alloc.h"
  17 #include "xfs_error.h"
  18 #include "xfs_extent_busy.h"
  19 #include "xfs_discard.h"
  20 #include "xfs_trace.h"
  21 #include "xfs_log.h"
  22
  23 STATIC int
  24 xfs_trim_extents(
  25         struct xfs_mount        *mp,
  26         xfs_agnumber_t          agno,
  27         xfs_daddr_t             start,
  28         xfs_daddr_t             end,
  29         xfs_daddr_t             minlen,
  30         uint64_t                *blocks_trimmed)
  31 {
  32         struct block_device     *bdev = mp->m_ddev_targp->bt_bdev;
  33         struct xfs_btree_cur    *cur;
  34         struct xfs_buf          *agbp;
  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 || !agbp)
  50                 goto out_put_perag;
  51
  52         cur = xfs_allocbt_init_cursor(mp, NULL, agbp, agno, XFS_BTNUM_CNT);
  53
  54         /*
  55          * Look up the longest btree in the AGF and start with it.
  56          */
  57         error = xfs_alloc_lookup_ge(cur, 0,
  58                             be32_to_cpu(XFS_BUF_TO_AGF(agbp)->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                 XFS_WANT_CORRUPTED_GOTO(mp, i == 1, out_del_cursor);
  76                 ASSERT(flen <= be32_to_cpu(XFS_BUF_TO_AGF(agbp)->agf_longest));
  77
  78                 /*
  79                  * use daddr format for all range/len calculations as that is
  80                  * the format the range/len variables are supplied in by
  81                  * userspace.
  82                  */
  83                 dbno = XFS_AGB_TO_DADDR(mp, agno, fbno);
  84                 dlen = XFS_FSB_TO_BB(mp, flen);
  85
  86                 /*
  87                  * Too small?  Give up.
  88                  */
  89                 if (dlen < minlen) {
  90                         trace_xfs_discard_toosmall(mp, agno, fbno, flen);
  91                         goto out_del_cursor;
  92                 }
  93
  94                 /*
  95                  * If the extent is entirely outside of the range we are
  96                  * supposed to discard skip it.  Do not bother to trim
  97                  * down partially overlapping ranges for now.
  98                  */
  99                 if (dbno + dlen < start || dbno > end) {
 100                         trace_xfs_discard_exclude(mp, agno, fbno, flen);
 101                         goto next_extent;
 102                 }
 103
 104                 /*
 105                  * If any blocks in the range are still busy, skip the
 106                  * discard and try again the next time.
 107                  */
 108                 if (xfs_extent_busy_search(mp, agno, fbno, flen)) {
 109                         trace_xfs_discard_busy(mp, agno, fbno, flen);
 110                         goto next_extent;
 111                 }
 112
 113                 trace_xfs_discard_extent(mp, agno, fbno, flen);
 114                 error = blkdev_issue_discard(bdev, dbno, dlen, GFP_NOFS, 0);
 115                 if (error)
 116                         goto out_del_cursor;
 117                 *blocks_trimmed += flen;
 118
 119 next_extent:
 120                 error = xfs_btree_decrement(cur, 0, &i);
 121                 if (error)
 122                         goto out_del_cursor;
 123
 124                 if (fatal_signal_pending(current)) {
 125                         error = -ERESTARTSYS;
 126                         goto out_del_cursor;
 127                 }
 128         }
 129
 130 out_del_cursor:
 131         xfs_btree_del_cursor(cur, error);
 132         xfs_buf_relse(agbp);
 133 out_put_perag:
 134         xfs_perag_put(pag);
 135         return error;
 136 }
 137
 138 /*
 139  * trim a range of the filesystem.
 140  *
 141  * Note: the parameters passed from userspace are byte ranges into the
 142  * filesystem which does not match to the format we use for filesystem block
 143  * addressing. FSB addressing is sparse (AGNO|AGBNO), while the incoming format
 144  * is a linear address range. Hence we need to use DADDR based conversions and
 145  * comparisons for determining the correct offset and regions to trim.
 146  */
 147 int
 148 xfs_ioc_trim(
 149         struct xfs_mount                *mp,
 150         struct fstrim_range __user      *urange)
 151 {
 152         struct request_queue    *q = bdev_get_queue(mp->m_ddev_targp->bt_bdev);
 153         unsigned int            granularity = q->limits.discard_granularity;
 154         struct fstrim_range     range;
 155         xfs_daddr_t             start, end, minlen;
 156         xfs_agnumber_t          start_agno, end_agno, agno;
 157         uint64_t                blocks_trimmed = 0;
 158         int                     error, last_error = 0;
 159
 160         if (!capable(CAP_SYS_ADMIN))
 161                 return -EPERM;
 162         if (!blk_queue_discard(q))
 163                 return -EOPNOTSUPP;
 164         if (copy_from_user(&range, urange, sizeof(range)))
 165                 return -EFAULT;
 166
 167         /*
 168          * Truncating down the len isn't actually quite correct, but using
 169          * BBTOB would mean we trivially get overflows for values
 170          * of ULLONG_MAX or slightly lower.  And ULLONG_MAX is the default
 171          * used by the fstrim application.  In the end it really doesn't
 172          * matter as trimming blocks is an advisory interface.
 173          */
 174         if (range.start >= XFS_FSB_TO_B(mp, mp->m_sb.sb_dblocks) ||
 175             range.minlen > XFS_FSB_TO_B(mp, mp->m_ag_max_usable) ||
 176             range.len < mp->m_sb.sb_blocksize)
 177                 return -EINVAL;
 178
 179         start = BTOBB(range.start);
 180         end = start + BTOBBT(range.len) - 1;
 181         minlen = BTOBB(max_t(u64, granularity, range.minlen));
 182
 183         if (end > XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) - 1)
 184                 end = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)- 1;
 185
 186         start_agno = xfs_daddr_to_agno(mp, start);
 187         end_agno = xfs_daddr_to_agno(mp, end);
 188
 189         for (agno = start_agno; agno <= end_agno; agno++) {
 190                 error = xfs_trim_extents(mp, agno, start, end, minlen,
 191                                           &blocks_trimmed);
 192                 if (error) {
 193                         last_error = error;
 194                         if (error == -ERESTARTSYS)
 195                                 break;
 196                 }
 197         }
 198
 199         if (last_error)
 200                 return last_error;
 201
 202         range.len = XFS_FSB_TO_B(mp, blocks_trimmed);
 203         if (copy_to_user(urange, &range, sizeof(range)))
 204                 return -EFAULT;
 205         return 0;
 206 }