linux/fs/xfs/xfs_discard.c
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   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_log.h"
  21#include "xfs_ag.h"
  22#include "xfs_mount.h"
  23#include "xfs_quota.h"
  24#include "xfs_trans.h"
  25#include "xfs_alloc_btree.h"
  26#include "xfs_bmap_btree.h"
  27#include "xfs_ialloc_btree.h"
  28#include "xfs_btree.h"
  29#include "xfs_inode.h"
  30#include "xfs_alloc.h"
  31#include "xfs_error.h"
  32#include "xfs_extent_busy.h"
  33#include "xfs_discard.h"
  34#include "xfs_trace.h"
  35
  36STATIC int
  37xfs_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_extent_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
 132next_extent:
 133                error = xfs_btree_decrement(cur, 0, &i);
 134                if (error)
 135                        goto out_del_cursor;
 136        }
 137
 138out_del_cursor:
 139        xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
 140        xfs_buf_relse(agbp);
 141out_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 */
 155int
 156xfs_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        if (range.start >= XFS_FSB_TO_B(mp, mp->m_sb.sb_dblocks) ||
 183            range.minlen > XFS_FSB_TO_B(mp, XFS_ALLOC_AG_MAX_USABLE(mp)))
 184                return -XFS_ERROR(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 -XFS_ERROR(EFAULT);
 209        return 0;
 210}
 211
 212int
 213xfs_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%llu,%u], error %d",
 231                                 (unsigned long long)busyp->bno,
 232                                 busyp->length,
 233                                 error);
 234                        return error;
 235                }
 236        }
 237
 238        return 0;
 239}
 240
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