xfs: implement the GETFSMAP ioctl
Introduce a new ioctl that uses the reverse mapping btree to return
information about the physical layout of the filesystem.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
diff --git a/fs/xfs/xfs_fsmap.h b/fs/xfs/xfs_fsmap.h
new file mode 100644
index 0000000..0b9bf82
--- /dev/null
+++ b/fs/xfs/xfs_fsmap.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2017 Oracle. All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ *
+ * 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; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * 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.
+ */
+#ifndef __XFS_FSMAP_H__
+#define __XFS_FSMAP_H__
+
+struct fsmap;
+
+/* internal fsmap representation */
+struct xfs_fsmap {
+ dev_t fmr_device; /* device id */
+ uint32_t fmr_flags; /* mapping flags */
+ uint64_t fmr_physical; /* device offset of segment */
+ uint64_t fmr_owner; /* owner id */
+ xfs_fileoff_t fmr_offset; /* file offset of segment */
+ xfs_filblks_t fmr_length; /* length of segment, blocks */
+};
+
+struct xfs_fsmap_head {
+ uint32_t fmh_iflags; /* control flags */
+ uint32_t fmh_oflags; /* output flags */
+ unsigned int fmh_count; /* # of entries in array incl. input */
+ unsigned int fmh_entries; /* # of entries filled in (output). */
+
+ struct xfs_fsmap fmh_keys[2]; /* low and high keys */
+};
+
+void xfs_fsmap_from_internal(struct fsmap *dest, struct xfs_fsmap *src);
+void xfs_fsmap_to_internal(struct xfs_fsmap *dest, struct fsmap *src);
+
+/* fsmap to userspace formatter - copy to user & advance pointer */
+typedef int (*xfs_fsmap_format_t)(struct xfs_fsmap *, void *);
+
+int xfs_getfsmap(struct xfs_mount *mp, struct xfs_fsmap_head *head,
+ xfs_fsmap_format_t formatter, void *arg);
+
+#endif /* __XFS_FSMAP_H__ */