fs/xfs/xfs_discard.c

   1 /*
   2  * Copyright (C) 2010 Red Hat, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #include "xfs.h"
  19 #include "xfs_sb.h"
  20 #include "xfs_inum.h"
  21 #include "xfs_log.h"
  22 #include "xfs_ag.h"
  23 #include "xfs_mount.h"
  24 #include "xfs_quota.h"
  25 #include "xfs_trans.h"
  26 #include "xfs_alloc_btree.h"
  27 #include "xfs_bmap_btree.h"
  28 #include "xfs_ialloc_btree.h"
  29 #include "xfs_btree.h"
  30 #include "xfs_inode.h"
  31 #include "xfs_alloc.h"
  32 #include "xfs_error.h"
  33 #include "xfs_discard.h"
  34 #include "xfs_trace.h"
  35
  36 STATIC int
  37 xfs_trim_extents(
  38         struct xfs_mount        *mp,
  39         xfs_agnumber_t          agno,
  40         xfs_daddr_t             start,
  41         xfs_daddr_t             end,
  42         xfs_daddr_t             minlen,
  43         __uint64_t              *blocks_trimmed)
  44 {
  45         struct block_device     *bdev = mp->m_ddev_targp->bt_bdev;
  46         struct xfs_btree_cur    *cur;
  47         struct xfs_buf          *agbp;
  48         struct xfs_perag        *pag;
  49         int                     error;
  50         int                     i;
  51
  52         pag = xfs_perag_get(mp, agno);
  53
  54         error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
  55         if (error || !agbp)
  56                 goto out_put_perag;
  57
  58         cur = xfs_allocbt_init_cursor(mp, NULL, agbp, agno, XFS_BTNUM_CNT);
  59
  60         /*
  61          * Force out the log.  This means any transactions that might have freed
  62          * space before we took the AGF buffer lock are now on disk, and the
  63          * volatile disk cache is flushed.
  64          */
  65         xfs_log_force(mp, XFS_LOG_SYNC);
  66
  67         /*
  68          * Look up the longest btree in the AGF and start with it.
  69          */
  70         error = xfs_alloc_lookup_ge(cur, 0,
  71                             be32_to_cpu(XFS_BUF_TO_AGF(agbp)->agf_longest), &i);
  72         if (error)
  73                 goto out_del_cursor;
  74
  75         /*
  76          * Loop until we are done with all extents that are large
  77          * enough to be worth discarding.
  78          */
  79         while (i) {
  80                 xfs_agblock_t   fbno;
  81                 xfs_extlen_t    flen;
  82                 xfs_daddr_t     dbno;
  83                 xfs_extlen_t    dlen;
  84
  85                 error = xfs_alloc_get_rec(cur, &fbno, &flen, &i);
  86                 if (error)
  87                         goto out_del_cursor;
  88                 XFS_WANT_CORRUPTED_GOTO(i == 1, out_del_cursor);
  89                 ASSERT(flen <= be32_to_cpu(XFS_BUF_TO_AGF(agbp)->agf_longest));
  90
  91                 /*
  92                  * use daddr format for all range/len calculations as that is
  93                  * the format the range/len variables are supplied in by
  94                  * userspace.
  95                  */
  96                 dbno = XFS_AGB_TO_DADDR(mp, agno, fbno);
  97                 dlen = XFS_FSB_TO_BB(mp, flen);
  98
  99                 /*
 100                  * Too small?  Give up.
 101                  */
 102                 if (dlen < minlen) {
 103                         trace_xfs_discard_toosmall(mp, agno, fbno, flen);
 104                         goto out_del_cursor;
 105                 }
 106
 107                 /*
 108                  * If the extent is entirely outside of the range we are
 109                  * supposed to discard skip it.  Do not bother to trim
 110                  * down partially overlapping ranges for now.
 111                  */
 112                 if (dbno + dlen < start || dbno > end) {
 113                         trace_xfs_discard_exclude(mp, agno, fbno, flen);
 114                         goto next_extent;
 115                 }
 116
 117                 /*
 118                  * If any blocks in the range are still busy, skip the
 119                  * discard and try again the next time.
 120                  */
 121                 if (xfs_alloc_busy_search(mp, agno, fbno, flen)) {
 122                         trace_xfs_discard_busy(mp, agno, fbno, flen);
 123                         goto next_extent;
 124                 }
 125
 126                 trace_xfs_discard_extent(mp, agno, fbno, flen);
 127                 error = -blkdev_issue_discard(bdev, dbno, dlen, GFP_NOFS, 0);
 128                 if (error)
 129                         goto out_del_cursor;
 130                 *blocks_trimmed += flen;
 131
 132 next_extent:
 133                 error = xfs_btree_decrement(cur, 0, &i);
 134                 if (error)
 135                         goto out_del_cursor;
 136         }
 137
 138 out_del_cursor:
 139         xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
 140         xfs_buf_relse(agbp);
 141 out_put_perag:
 142         xfs_perag_put(pag);
 143         return error;
 144 }
 145
 146 /*
 147  * trim a range of the filesystem.
 148  *
 149  * Note: the parameters passed from userspace are byte ranges into the
 150  * filesystem which does not match to the format we use for filesystem block
 151  * addressing. FSB addressing is sparse (AGNO|AGBNO), while the incoming format
 152  * is a linear address range. Hence we need to use DADDR based conversions and
 153  * comparisons for determining the correct offset and regions to trim.
 154  */
 155 int
 156 xfs_ioc_trim(
 157         struct xfs_mount                *mp,
 158         struct fstrim_range __user      *urange)
 159 {
 160         struct request_queue    *q = mp->m_ddev_targp->bt_bdev->bd_disk->queue;
 161         unsigned int            granularity = q->limits.discard_granularity;
 162         struct fstrim_range     range;
 163         xfs_daddr_t             start, end, minlen;
 164         xfs_agnumber_t          start_agno, end_agno, agno;
 165         __uint64_t              blocks_trimmed = 0;
 166         int                     error, last_error = 0;
 167
 168         if (!capable(CAP_SYS_ADMIN))
 169                 return -XFS_ERROR(EPERM);
 170         if (!blk_queue_discard(q))
 171                 return -XFS_ERROR(EOPNOTSUPP);
 172         if (copy_from_user(&range, urange, sizeof(range)))
 173                 return -XFS_ERROR(EFAULT);
 174
 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         start = BTOBB(range.start);
 183         end = start + BTOBBT(range.len) - 1;
 184         minlen = BTOBB(max_t(u64, granularity, range.minlen));
 185
 186         if (XFS_BB_TO_FSB(mp, start) >= mp->m_sb.sb_dblocks)
 187                 return -XFS_ERROR(EINVAL);
 188         if (end > XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) - 1)
 189                 end = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)- 1;
 190
 191         start_agno = xfs_daddr_to_agno(mp, start);
 192         end_agno = xfs_daddr_to_agno(mp, end);
 193
 194         for (agno = start_agno; agno <= end_agno; agno++) {
 195                 error = -xfs_trim_extents(mp, agno, start, end, minlen,
 196                                           &blocks_trimmed);
 197                 if (error)
 198                         last_error = error;
 199         }
 200
 201         if (last_error)
 202                 return last_error;
 203
 204         range.len = XFS_FSB_TO_B(mp, blocks_trimmed);
 205         if (copy_to_user(urange, &range, sizeof(range)))
 206                 return -XFS_ERROR(EFAULT);
 207         return 0;
 208 }
 209
 210 int
 211 xfs_discard_extents(
 212         struct xfs_mount        *mp,
 213         struct list_head        *list)
 214 {
 215         struct xfs_busy_extent  *busyp;
 216         int                     error = 0;
 217
 218         list_for_each_entry(busyp, list, list) {
 219                 trace_xfs_discard_extent(mp, busyp->agno, busyp->bno,
 220                                          busyp->length);
 221
 222                 error = -blkdev_issue_discard(mp->m_ddev_targp->bt_bdev,
 223                                 XFS_AGB_TO_DADDR(mp, busyp->agno, busyp->bno),
 224                                 XFS_FSB_TO_BB(mp, busyp->length),
 225                                 GFP_NOFS, 0);
 226                 if (error && error != EOPNOTSUPP) {
 227                         xfs_info(mp,
 228          "discard failed for extent [0x%llu,%u], error %d",
 229                                  (unsigned long long)busyp->bno,
 230                                  busyp->length,
 231                                  error);
 232                         return error;
 233                 }
 234         }
 235
 236         return 0;
 237 }