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_format.h"
  20 #include "xfs_log_format.h"
  21 #include "xfs_trans_resv.h"
  22 #include "xfs_sb.h"
  23 #include "xfs_mount.h"
  24 #include "xfs_quota.h"
  25 #include "xfs_inode.h"
  26 #include "xfs_btree.h"
  27 #include "xfs_alloc_btree.h"
  28 #include "xfs_alloc.h"
  29 #include "xfs_error.h"
  30 #include "xfs_extent_busy.h"
  31 #include "xfs_discard.h"
  32 #include "xfs_trace.h"
  33 #include "xfs_log.h"
  34
  35 STATIC int
  36 xfs_trim_extents(
  37         struct xfs_mount        *mp,
  38         xfs_agnumber_t          agno,
  39         xfs_daddr_t             start,
  40         xfs_daddr_t             end,
  41         xfs_daddr_t             minlen,
  42         __uint64_t              *blocks_trimmed)
  43 {
  44         struct block_device     *bdev = mp->m_ddev_targp->bt_bdev;
  45         struct xfs_btree_cur    *cur;
  46         struct xfs_buf          *agbp;
  47         struct xfs_perag        *pag;
  48         int                     error;
  49         int                     i;
  50
  51         pag = xfs_perag_get(mp, agno);
  52
  53         error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
  54         if (error || !agbp)
  55                 goto out_put_perag;
  56
  57         cur = xfs_allocbt_init_cursor(mp, NULL, agbp, agno, XFS_BTNUM_CNT);
  58
  59         /*
  60          * Force out the log.  This means any transactions that might have freed
  61          * space before we took the AGF buffer lock are now on disk, and the
  62          * volatile disk cache is flushed.
  63          */
  64         xfs_log_force(mp, XFS_LOG_SYNC);
  65
  66         /*
  67          * Look up the longest btree in the AGF and start with it.
  68          */
  69         error = xfs_alloc_lookup_ge(cur, 0,
  70                             be32_to_cpu(XFS_BUF_TO_AGF(agbp)->agf_longest), &i);
  71         if (error)
  72                 goto out_del_cursor;
  73
  74         /*
  75          * Loop until we are done with all extents that are large
  76          * enough to be worth discarding.
  77          */
  78         while (i) {
  79                 xfs_agblock_t   fbno;
  80                 xfs_extlen_t    flen;
  81                 xfs_daddr_t     dbno;
  82                 xfs_extlen_t    dlen;
  83
  84                 error = xfs_alloc_get_rec(cur, &fbno, &flen, &i);
  85                 if (error)
  86                         goto out_del_cursor;
  87                 XFS_WANT_CORRUPTED_GOTO(mp, i == 1, out_del_cursor);
  88                 ASSERT(flen <= be32_to_cpu(XFS_BUF_TO_AGF(agbp)->agf_longest));
  89
  90                 /*
  91                  * use daddr format for all range/len calculations as that is
  92                  * the format the range/len variables are supplied in by
  93                  * userspace.
  94                  */
  95                 dbno = XFS_AGB_TO_DADDR(mp, agno, fbno);
  96                 dlen = XFS_FSB_TO_BB(mp, flen);
  97
  98                 /*
  99                  * Too small?  Give up.
 100                  */
 101                 if (dlen < minlen) {
 102                         trace_xfs_discard_toosmall(mp, agno, fbno, flen);
 103                         goto out_del_cursor;
 104                 }
 105
 106                 /*
 107                  * If the extent is entirely outside of the range we are
 108                  * supposed to discard skip it.  Do not bother to trim
 109                  * down partially overlapping ranges for now.
 110                  */
 111                 if (dbno + dlen < start || dbno > end) {
 112                         trace_xfs_discard_exclude(mp, agno, fbno, flen);
 113                         goto next_extent;
 114                 }
 115
 116                 /*
 117                  * If any blocks in the range are still busy, skip the
 118                  * discard and try again the next time.
 119                  */
 120                 if (xfs_extent_busy_search(mp, agno, fbno, flen)) {
 121                         trace_xfs_discard_busy(mp, agno, fbno, flen);
 122                         goto next_extent;
 123                 }
 124
 125                 trace_xfs_discard_extent(mp, agno, fbno, flen);
 126                 error = blkdev_issue_discard(bdev, dbno, dlen, GFP_NOFS, 0);
 127                 if (error)
 128                         goto out_del_cursor;
 129                 *blocks_trimmed += flen;
 130
 131 next_extent:
 132                 error = xfs_btree_decrement(cur, 0, &i);
 133                 if (error)
 134                         goto out_del_cursor;
 135         }
 136
 137 out_del_cursor:
 138         xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
 139         xfs_buf_relse(agbp);
 140 out_put_perag:
 141         xfs_perag_put(pag);
 142         return error;
 143 }
 144
 145 /*
 146  * trim a range of the filesystem.
 147  *
 148  * Note: the parameters passed from userspace are byte ranges into the
 149  * filesystem which does not match to the format we use for filesystem block
 150  * addressing. FSB addressing is sparse (AGNO|AGBNO), while the incoming format
 151  * is a linear address range. Hence we need to use DADDR based conversions and
 152  * comparisons for determining the correct offset and regions to trim.
 153  */
 154 int
 155 xfs_ioc_trim(
 156         struct xfs_mount                *mp,
 157         struct fstrim_range __user      *urange)
 158 {
 159         struct request_queue    *q = bdev_get_queue(mp->m_ddev_targp->bt_bdev);
 160         unsigned int            granularity = q->limits.discard_granularity;
 161         struct fstrim_range     range;
 162         xfs_daddr_t             start, end, minlen;
 163         xfs_agnumber_t          start_agno, end_agno, agno;
 164         __uint64_t              blocks_trimmed = 0;
 165         int                     error, last_error = 0;
 166
 167         if (!capable(CAP_SYS_ADMIN))
 168                 return -EPERM;
 169         if (!blk_queue_discard(q))
 170                 return -EOPNOTSUPP;
 171         if (copy_from_user(&range, urange, sizeof(range)))
 172                 return -EFAULT;
 173
 174         /*
 175          * Truncating down the len isn't actually quite correct, but using
 176          * BBTOB would mean we trivially get overflows for values
 177          * of ULLONG_MAX or slightly lower.  And ULLONG_MAX is the default
 178          * used by the fstrim application.  In the end it really doesn't
 179          * matter as trimming blocks is an advisory interface.
 180          */
 181         if (range.start >= XFS_FSB_TO_B(mp, mp->m_sb.sb_dblocks) ||
 182             range.minlen > XFS_FSB_TO_B(mp, XFS_ALLOC_AG_MAX_USABLE(mp)) ||
 183             range.len < mp->m_sb.sb_blocksize)
 184                 return -EINVAL;
 185
 186         start = BTOBB(range.start);
 187         end = start + BTOBBT(range.len) - 1;
 188         minlen = BTOBB(max_t(u64, granularity, range.minlen));
 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         }
 202
 203         if (last_error)
 204                 return last_error;
 205
 206         range.len = XFS_FSB_TO_B(mp, blocks_trimmed);
 207         if (copy_to_user(urange, &range, sizeof(range)))
 208                 return -EFAULT;
 209         return 0;
 210 }
 211
 212 int
 213 xfs_discard_extents(
 214         struct xfs_mount        *mp,
 215         struct list_head        *list)
 216 {
 217         struct xfs_extent_busy  *busyp;
 218         int                     error = 0;
 219
 220         list_for_each_entry(busyp, list, list) {
 221                 trace_xfs_discard_extent(mp, busyp->agno, busyp->bno,
 222                                          busyp->length);
 223
 224                 error = blkdev_issue_discard(mp->m_ddev_targp->bt_bdev,
 225                                 XFS_AGB_TO_DADDR(mp, busyp->agno, busyp->bno),
 226                                 XFS_FSB_TO_BB(mp, busyp->length),
 227                                 GFP_NOFS, 0);
 228                 if (error && error != -EOPNOTSUPP) {
 229                         xfs_info(mp,
 230          "discard failed for extent [0x%llx,%u], error %d",
 231                                  (unsigned long long)busyp->bno,
 232                                  busyp->length,
 233                                  error);
 234                         return error;
 235                 }
 236         }
 237
 238         return 0;
 239 }