v4.19.13 snapshot.
diff --git a/fs/xfs/xfs_discard.c b/fs/xfs/xfs_discard.c
new file mode 100644
index 0000000..93f07ed
--- /dev/null
+++ b/fs/xfs/xfs_discard.c
@@ -0,0 +1,206 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2010 Red Hat, Inc.
+ * All Rights Reserved.
+ */
+#include "xfs.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_sb.h"
+#include "xfs_mount.h"
+#include "xfs_quota.h"
+#include "xfs_inode.h"
+#include "xfs_btree.h"
+#include "xfs_alloc_btree.h"
+#include "xfs_alloc.h"
+#include "xfs_error.h"
+#include "xfs_extent_busy.h"
+#include "xfs_discard.h"
+#include "xfs_trace.h"
+#include "xfs_log.h"
+
+STATIC int
+xfs_trim_extents(
+ struct xfs_mount *mp,
+ xfs_agnumber_t agno,
+ xfs_daddr_t start,
+ xfs_daddr_t end,
+ xfs_daddr_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);
+
+ /*
+ * Force out the log. This means any transactions that might have freed
+ * space before we take the AGF buffer lock are now on disk, and the
+ * volatile disk cache is flushed.
+ */
+ xfs_log_force(mp, XFS_LOG_SYNC);
+
+ 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);
+
+ /*
+ * Look up the longest btree in the AGF and start with it.
+ */
+ error = xfs_alloc_lookup_ge(cur, 0,
+ be32_to_cpu(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;
+ xfs_daddr_t dbno;
+ xfs_extlen_t dlen;
+
+ error = xfs_alloc_get_rec(cur, &fbno, &flen, &i);
+ if (error)
+ goto out_del_cursor;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, out_del_cursor);
+ ASSERT(flen <= be32_to_cpu(XFS_BUF_TO_AGF(agbp)->agf_longest));
+
+ /*
+ * use daddr format for all range/len calculations as that is
+ * the format the range/len variables are supplied in by
+ * userspace.
+ */
+ dbno = XFS_AGB_TO_DADDR(mp, agno, fbno);
+ dlen = XFS_FSB_TO_BB(mp, flen);
+
+ /*
+ * Too small? Give up.
+ */
+ if (dlen < 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 (dbno + dlen < start || dbno > end) {
+ 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_extent_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, dbno, dlen, 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;
+
+ if (fatal_signal_pending(current)) {
+ error = -ERESTARTSYS;
+ goto out_del_cursor;
+ }
+ }
+
+out_del_cursor:
+ xfs_btree_del_cursor(cur, error);
+ xfs_buf_relse(agbp);
+out_put_perag:
+ xfs_perag_put(pag);
+ return error;
+}
+
+/*
+ * trim a range of the filesystem.
+ *
+ * Note: the parameters passed from userspace are byte ranges into the
+ * filesystem which does not match to the format we use for filesystem block
+ * addressing. FSB addressing is sparse (AGNO|AGBNO), while the incoming format
+ * is a linear address range. Hence we need to use DADDR based conversions and
+ * comparisons for determining the correct offset and regions to trim.
+ */
+int
+xfs_ioc_trim(
+ struct xfs_mount *mp,
+ struct fstrim_range __user *urange)
+{
+ struct request_queue *q = bdev_get_queue(mp->m_ddev_targp->bt_bdev);
+ unsigned int granularity = q->limits.discard_granularity;
+ struct fstrim_range range;
+ xfs_daddr_t start, end, 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 -EPERM;
+ if (!blk_queue_discard(q))
+ return -EOPNOTSUPP;
+ if (copy_from_user(&range, urange, sizeof(range)))
+ return -EFAULT;
+
+ /*
+ * Truncating down the len isn't actually quite correct, but using
+ * BBTOB 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.
+ */
+ if (range.start >= XFS_FSB_TO_B(mp, mp->m_sb.sb_dblocks) ||
+ range.minlen > XFS_FSB_TO_B(mp, mp->m_ag_max_usable) ||
+ range.len < mp->m_sb.sb_blocksize)
+ return -EINVAL;
+
+ start = BTOBB(range.start);
+ end = start + BTOBBT(range.len) - 1;
+ minlen = BTOBB(max_t(u64, granularity, range.minlen));
+
+ if (end > XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) - 1)
+ end = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)- 1;
+
+ start_agno = xfs_daddr_to_agno(mp, start);
+ end_agno = xfs_daddr_to_agno(mp, end);
+
+ for (agno = start_agno; agno <= end_agno; agno++) {
+ error = xfs_trim_extents(mp, agno, start, end, minlen,
+ &blocks_trimmed);
+ if (error) {
+ last_error = error;
+ if (error == -ERESTARTSYS)
+ break;
+ }
+ }
+
+ if (last_error)
+ return last_error;
+
+ range.len = XFS_FSB_TO_B(mp, blocks_trimmed);
+ if (copy_to_user(urange, &range, sizeof(range)))
+ return -EFAULT;
+ return 0;
+}