From: Dave Chinner <dchinner@xxxxxxxxxx>
As you wish.
Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
---
fs/xfs/xfs_alloc.c | 219 ++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/xfs_alloc.h | 7 ++
fs/xfs/xfs_iops.c | 12 ++-
3 files changed, 237 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/xfs_alloc.c b/fs/xfs/xfs_alloc.c
index 335206a..ee680c9 100644
--- a/fs/xfs/xfs_alloc.c
+++ b/fs/xfs/xfs_alloc.c
@@ -2470,3 +2470,222 @@ error0:
xfs_perag_put(args.pag);
return error;
}
+
+/*
+ * Walk the extents in the tree given by the cursor, and dump them all into the
+ * fieinfo. At the last extent in the tree, set the FIEMAP_EXTENT_LAST flag so
+ * that we return only free space from this tree in a given request.
+ */
+static int
+xfs_alloc_ag_freespace_map(
+ struct xfs_btree_cur *cur,
+ struct fiemap_extent_info *fieinfo,
+ xfs_agblock_t sagbno,
+ xfs_agblock_t eagbno)
+{
+ int error = 0;
+ int i = 1;
+
+ /*
+ * Loop until we have either filled the fiemap or reached the end of
+ * the AG walk.
+ */
+ while (i) {
+ xfs_agblock_t fbno;
+ xfs_extlen_t flen;
+ xfs_daddr_t dbno;
+ xfs_fileoff_t dlen;
+ int flags = 0;
+
+ error = xfs_alloc_get_rec(cur, &fbno, &flen, &i);
+ if (error)
+ break;
+ XFS_WANT_CORRUPTED_RETURN(i == 1);
+
+ /*
+ * move the cursor now to make it easy to continue the loop and
+ * detect the last extent in the lookup.
+ */
+ error = xfs_btree_increment(cur, 0, &i);
+ if (error)
+ break;
+
+ /* range check - must be wholly withing requested range */
+ if (fbno < sagbno ||
+ (eagbno != NULLAGBLOCK && fbno + flen > eagbno)) {
+ xfs_warn(cur->bc_mp, "10: %d/%d, %d/%d", sagbno, eagbno, fbno, flen);
+ continue;
+ }
+
+ /*
+ * 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(cur->bc_mp, cur->bc_private.a.agno, fbno);
+ dlen = XFS_FSB_TO_BB(cur->bc_mp, flen);
+
+ if (i == 0)
+ flags |= FIEMAP_EXTENT_LAST;
+ error = -fiemap_fill_next_extent(fieinfo, BBTOB(dbno),
+ BBTOB(dbno), BBTOB(dlen), flags);
+ if (error)
+ break;
+ }
+ return error;
+
+}
+
+/*
+ * Map the freespace from the requested range in the requested order.
+ *
+ * To make things simple, this function will only return the freespace from a
+ * single AG regardless of the size of the map passed in. That AG will be the AG
+ * that the first freespace is found in. In other words, FIEMAP_EXTENT_LAST does
+ * not mean the last freespace extent has been mapped, just that the last extent
+ * in a given freespace index has been mapped. The caller is responsible for
+ * moving the range to the next freespace region if it needs to query for more
+ * information.
+ *
+ * IOWs, the caller is responsible for knowing about the XFS filesystem
+ * structure and how it indexes freespace to use this call effectively.
+ */
+#define XFS_FREESP_FLAGS (FIEMAP_FLAG_FREESPACE | FIEMAP_FLAG_FREESPACE_SIZE)
+int
+xfs_alloc_freespace_map(
+ struct xfs_mount *mp,
+ struct fiemap_extent_info *fieinfo,
+ u64 start,
+ u64 length)
+{
+ struct xfs_btree_cur *cur;
+ struct xfs_buf *agbp;
+ struct xfs_perag *pag;
+ xfs_agnumber_t agno;
+ xfs_agnumber_t sagno;
+ xfs_agblock_t sagbno;
+ xfs_agnumber_t eagno;
+ xfs_agblock_t eagbno;
+ bool bycnt;
+ int error = 0;
+
+ /* can only have one type of mapping */
+ if ((fieinfo->fi_flags & XFS_FREESP_FLAGS) == XFS_FREESP_FLAGS) {
+ xfs_warn(mp, "1: 0x%x\n", fieinfo->fi_flags);
+ return EINVAL;
+ }
+ bycnt = (fieinfo->fi_flags & FIEMAP_FLAG_FREESPACE_SIZE);
+
+ if (XFS_B_TO_FSB(mp, start) >= mp->m_sb.sb_dblocks) {
+ xfs_warn(mp, "2: %lld, %lld/%lld\n", start,
+ XFS_B_TO_FSB(mp, start), mp->m_sb.sb_dblocks);
+ return EINVAL;
+ }
+ if (length < mp->m_sb.sb_blocksize) {
+ xfs_warn(mp, "3: %lld, %d\n", length, mp->m_sb.sb_blocksize);
+ return EINVAL;
+ }
+ if (start + length < start) {
+ xfs_warn(mp, "4: %lld/%lld, %lld", start, length, start + length);
+ return EINVAL;
+ }
+
+ sagno = xfs_daddr_to_agno(mp, BTOBB(start));
+ sagbno = xfs_daddr_to_agbno(mp, BTOBB(start));
+
+ eagno = xfs_daddr_to_agno(mp, BTOBB(start + length));
+ eagbno = xfs_daddr_to_agbno(mp, BTOBB(start + length));
+
+ if (sagno == eagno && sagbno == eagbno) {
+ xfs_warn(mp, "5: %d/%d, %d/%d", sagno, eagno, sagbno, eagbno);
+ return EINVAL;
+ }
+
+ /*
+ * 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);
+
+ /*
+ * Do initial lookup in by-bno tree. Keep skipping AGs until with
+ * either find a free space extent or reach the end of the search.
+ */
+ for (agno = sagno; agno < eagno; agno++) {
+ int i;
+ error = 0;
+
+ error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
+ if (error || !agbp) {
+ xfs_warn(mp, "7: %p, %d", agbp, error);
+ goto next;
+ }
+
+ pag = xfs_perag_get(mp, agno);
+ if (pag->pagf_freeblks <= pag->pagf_flcount) {
+ /* no free space worth reporting */
+ xfs_warn(mp, "6: %d %d", pag->pagf_freeblks,
+ pag->pagf_flcount);
+ goto put_agbp;
+ }
+
+ cur = xfs_allocbt_init_cursor(mp, NULL, agbp, agno,
+ XFS_BTNUM_BNO);
+ error = xfs_alloc_lookup_ge(cur, 0, sagbno, &i);
+ if (error) {
+ xfs_warn(mp, "8: %d/%d, %d/%d", sagno, eagno, sagbno, eagbno);
+ goto del_cursor;
+ }
+ XFS_WANT_CORRUPTED_GOTO(i == 1, del_cursor);
+
+ if (!bycnt) {
+ /*
+ * if we are doing a bno ordered lookup, we can just
+ * loop across the free space extents formatting them
+ * until we get to the end of the AG, eagbno or fill the
+ * fieinfo map.
+ */
+ error = xfs_alloc_ag_freespace_map(cur, fieinfo, sagbno,
+ agno == eagno ? eagbno : NULLAGBLOCK);
+ } else {
+ /*
+ * We are doing a size ordered lookup. We know there is
+ * a free space extent somewhere past out start bno, so
+ * just kill the current cursor and start a size
+ * ordered scan to find all the freespace in the given
+ * range.
+ */
+ xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
+ cur = xfs_allocbt_init_cursor(mp, NULL, agbp, agno,
+ XFS_BTNUM_CNT);
+ error = xfs_alloc_lookup_ge(cur, 0, 1, &i);
+ if (error)
+ goto del_cursor;
+ XFS_WANT_CORRUPTED_GOTO(i == 1, del_cursor);
+
+ error = xfs_alloc_ag_freespace_map(cur, fieinfo, sagbno,
+ agno == eagno ? eagbno : NULLAGBLOCK);
+ }
+
+del_cursor:
+ xfs_btree_del_cursor(cur, error < 0 ? XFS_BTREE_ERROR
+ : XFS_BTREE_NOERROR);
+put_agbp:
+ xfs_perag_put(pag);
+ xfs_buf_relse(agbp);
+next:
+ if (error)
+ break;
+ sagbno = 0;
+ }
+
+ /*
+ * negative errno indicates that we hit a FIEMAP_EXTENT_LAST flag. Clear
+ * the error in that case.
+ */
+ if (error < 0)
+ error = 0;
+
+ return error;;
+}
diff --git a/fs/xfs/xfs_alloc.h b/fs/xfs/xfs_alloc.h
index feacb06..371b02c 100644
--- a/fs/xfs/xfs_alloc.h
+++ b/fs/xfs/xfs_alloc.h
@@ -231,4 +231,11 @@ xfs_alloc_get_rec(
xfs_extlen_t *len, /* output: length of extent */
int *stat); /* output: success/failure */
+int
+xfs_alloc_freespace_map(
+ struct xfs_mount *mp,
+ struct fiemap_extent_info *fieinfo,
+ u64 start,
+ u64 length);
+
#endif /* __XFS_ALLOC_H__ */
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 4e00cf0..4555525 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -938,7 +938,9 @@ xfs_vn_update_time(
return -xfs_trans_commit(tp, 0);
}
-#define XFS_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
+#define XFS_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC | FIEMAP_FLAG_XATTR | \
+ FIEMAP_FLAG_FREESPACE | \
+ FIEMAP_FLAG_FREESPACE_SIZE)
/*
* Call fiemap helper to fill in user data.
@@ -997,6 +999,13 @@ xfs_vn_fiemap(
if (error)
return error;
+ if ((fieinfo->fi_flags &
+ (FIEMAP_FLAG_FREESPACE | FIEMAP_FLAG_FREESPACE_SIZE))) {
+ error = xfs_alloc_freespace_map(ip->i_mount, fieinfo,
+ start, length);
+ goto out;
+ }
+
/* Set up bmap header for xfs internal routine */
bm.bmv_offset = BTOBB(start);
/* Special case for whole file */
@@ -1017,6 +1026,7 @@ xfs_vn_fiemap(
bm.bmv_iflags |= BMV_IF_DELALLOC;
error = xfs_getbmap(ip, &bm, xfs_fiemap_format, fieinfo);
+out:
if (error)
return -error;
--
1.7.10
--
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