1 files changed, 222 insertions, 0 deletions

diff --git a/fs/xfs/xfs_discard.c b/fs/xfs/xfs_discard.c
new file mode 100644
index 000000000000..244e797dae32
--- /dev/null
+++ b/fs/xfs/xfs_discard.c
@@ -0,0 +1,222 @@
+/*
+ * Copyright (C) 2010 Red Hat, Inc.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#include "xfs.h"
+#include "xfs_sb.h"
+#include "xfs_inum.h"
+#include "xfs_log.h"
+#include "xfs_ag.h"
+#include "xfs_mount.h"
+#include "xfs_quota.h"
+#include "xfs_trans.h"
+#include "xfs_alloc_btree.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_ialloc_btree.h"
+#include "xfs_btree.h"
+#include "xfs_inode.h"
+#include "xfs_alloc.h"
+#include "xfs_error.h"
+#include "xfs_discard.h"
+#include "xfs_trace.h"
+
+STATIC int
+xfs_trim_extents(
+        struct xfs_mount        *mp,
+        xfs_agnumber_t          agno,
+        xfs_fsblock_t           start,
+        xfs_fsblock_t           len,
+        xfs_fsblock_t           minlen,
+        __uint64_t              *blocks_trimmed)
+{
+        struct block_device     *bdev = mp->m_ddev_targp->bt_bdev;
+        struct xfs_btree_cur    *cur;
+        struct xfs_buf          *agbp;
+        struct xfs_perag        *pag;
+        int                     error;
+        int                     i;
+
+        pag = xfs_perag_get(mp, agno);
+
+        error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
+        if (error || !agbp)
+                goto out_put_perag;
+
+        cur = xfs_allocbt_init_cursor(mp, NULL, agbp, agno, XFS_BTNUM_CNT);
+
+        /*
+         * Force out the log.  This means any transactions that might have freed
+         * space before we took the AGF buffer lock are now on disk, and the
+         * volatile disk cache is flushed.
+         */
+        xfs_log_force(mp, XFS_LOG_SYNC);
+
+        /*
+         * Look up the longest btree in the AGF and start with it.
+         */
+        error = xfs_alloc_lookup_le(cur, 0,
+                                    XFS_BUF_TO_AGF(agbp)->agf_longest, &i);
+        if (error)
+                goto out_del_cursor;
+
+        /*
+         * Loop until we are done with all extents that are large
+         * enough to be worth discarding.
+         */
+        while (i) {
+                xfs_agblock_t fbno;
+                xfs_extlen_t flen;
+
+                error = xfs_alloc_get_rec(cur, &fbno, &flen, &i);
+                if (error)
+                        goto out_del_cursor;
+                XFS_WANT_CORRUPTED_GOTO(i == 1, out_del_cursor);
+                ASSERT(flen <= XFS_BUF_TO_AGF(agbp)->agf_longest);
+
+                /*
+                 * Too small?  Give up.
+                 */
+                if (flen < minlen) {
+                        trace_xfs_discard_toosmall(mp, agno, fbno, flen);
+                        goto out_del_cursor;
+                }
+
+                /*
+                 * If the extent is entirely outside of the range we are
+                 * supposed to discard skip it.  Do not bother to trim
+                 * down partially overlapping ranges for now.
+                 */
+                if (XFS_AGB_TO_FSB(mp, agno, fbno) + flen < start ||
+                    XFS_AGB_TO_FSB(mp, agno, fbno) >= start + len) {
+                        trace_xfs_discard_exclude(mp, agno, fbno, flen);
+                        goto next_extent;
+                }
+
+                /*
+                 * If any blocks in the range are still busy, skip the
+                 * discard and try again the next time.
+                 */
+                if (xfs_alloc_busy_search(mp, agno, fbno, flen)) {
+                        trace_xfs_discard_busy(mp, agno, fbno, flen);
+                        goto next_extent;
+                }
+
+                trace_xfs_discard_extent(mp, agno, fbno, flen);
+                error = -blkdev_issue_discard(bdev,
+                                XFS_AGB_TO_DADDR(mp, agno, fbno),
+                                XFS_FSB_TO_BB(mp, flen),
+                                GFP_NOFS, 0);
+                if (error)
+                        goto out_del_cursor;
+                *blocks_trimmed += flen;
+
+next_extent:
+                error = xfs_btree_decrement(cur, 0, &i);
+                if (error)
+                        goto out_del_cursor;
+        }
+
+out_del_cursor:
+        xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
+        xfs_buf_relse(agbp);
+out_put_perag:
+        xfs_perag_put(pag);
+        return error;
+}
+
+int
+xfs_ioc_trim(
+        struct xfs_mount                *mp,
+        struct fstrim_range __user      *urange)
+{
+        struct request_queue    *q = mp->m_ddev_targp->bt_bdev->bd_disk->queue;
+        unsigned int            granularity = q->limits.discard_granularity;
+        struct fstrim_range     range;
+        xfs_fsblock_t           start, len, minlen;
+        xfs_agnumber_t          start_agno, end_agno, agno;
+        __uint64_t              blocks_trimmed = 0;
+        int                     error, last_error = 0;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -XFS_ERROR(EPERM);
+        if (!blk_queue_discard(q))
+                return -XFS_ERROR(EOPNOTSUPP);
+        if (copy_from_user(&range, urange, sizeof(range)))
+                return -XFS_ERROR(EFAULT);
+
+        /*
+         * Truncating down the len isn't actually quite correct, but using
+         * XFS_B_TO_FSB would mean we trivially get overflows for values
+         * of ULLONG_MAX or slightly lower.  And ULLONG_MAX is the default
+         * used by the fstrim application.  In the end it really doesn't
+         * matter as trimming blocks is an advisory interface.
+         */
+        start = XFS_B_TO_FSBT(mp, range.start);
+        len = XFS_B_TO_FSBT(mp, range.len);
+        minlen = XFS_B_TO_FSB(mp, max_t(u64, granularity, range.minlen));
+
+        start_agno = XFS_FSB_TO_AGNO(mp, start);
+        if (start_agno >= mp->m_sb.sb_agcount)
+                return -XFS_ERROR(EINVAL);
+
+        end_agno = XFS_FSB_TO_AGNO(mp, start + len);
+        if (end_agno >= mp->m_sb.sb_agcount)
+                end_agno = mp->m_sb.sb_agcount - 1;
+
+        for (agno = start_agno; agno <= end_agno; agno++) {
+                error = -xfs_trim_extents(mp, agno, start, len, minlen,
+                                          &blocks_trimmed);
+                if (error)
+                        last_error = error;
+        }
+
+        if (last_error)
+                return last_error;
+
+        range.len = XFS_FSB_TO_B(mp, blocks_trimmed);
+        if (copy_to_user(urange, &range, sizeof(range)))
+                return -XFS_ERROR(EFAULT);
+        return 0;
+}
+
+int
+xfs_discard_extents(
+        struct xfs_mount        *mp,
+        struct list_head        *list)
+{
+        struct xfs_busy_extent  *busyp;
+        int                     error = 0;
+
+        list_for_each_entry(busyp, list, list) {
+                trace_xfs_discard_extent(mp, busyp->agno, busyp->bno,
+                                         busyp->length);
+
+                error = -blkdev_issue_discard(mp->m_ddev_targp->bt_bdev,
+                                XFS_AGB_TO_DADDR(mp, busyp->agno, busyp->bno),
+                                XFS_FSB_TO_BB(mp, busyp->length),
+                                GFP_NOFS, 0);
+                if (error && error != EOPNOTSUPP) {
+                        xfs_info(mp,
+         "discard failed for extent [0x%llu,%u], error %d",
+                                 (unsigned long long)busyp->bno,
+                                 busyp->length,
+                                 error);
+                        return error;
+                }
+        }
+
+        return 0;
+}