cp: copy sparse files efficiently using the FIEMAP ioctl

* src/fiemap.h: Add fiemap.h for fiemap ioctl(2) support.  Copied
from linux's include/linux/fiemap.h, with minor formatting changes.
* src/copy.c (copy_reg): Now, when `cp' is invoked with --sparse=[WHEN],
we will try to do FIEMAP-copy if the underlying file system
supports it, and fall back to a normal copy if it fails.

1 files changed, 102 insertions, 0 deletions

diff --git a/src/fiemap.h b/src/fiemap.h
new file mode 100644
index 000000000..d33293b5c
--- /dev/null
+++ b/src/fiemap.h
@@ -0,0 +1,102 @@
+/* FS_IOC_FIEMAP ioctl infrastructure.
+   Some portions copyright (C) 2007 Cluster File Systems, Inc
+   Authors: Mark Fasheh <mfasheh@suse.com>
+            Kalpak Shah <kalpak.shah@sun.com>
+            Andreas Dilger <adilger@sun.com>.  */
+
+/* Copy from kernel, modified to respect GNU code style by Jie Liu.  */
+
+#ifndef _LINUX_FIEMAP_H
+# define _LINUX_FIEMAP_H
+
+# include <linux/types.h>
+
+struct fiemap_extent
+{
+  /* Logical offset in bytes for the start of the extent
+     from the beginning of the file.  */
+  uint64_t fe_logical;
+
+  /* Physical offset in bytes for the start of the extent
+     from the beginning of the disk.  */
+  uint64_t fe_physical;
+
+  /* Length in bytes for this extent.  */
+  uint64_t fe_length;
+
+  uint64_t fe_reserved64[2];
+
+  /* FIEMAP_EXTENT_* flags for this extent.  */
+  uint32_t fe_flags;
+
+  uint32_t fe_reserved[3];
+};
+
+struct fiemap
+{
+  /* Logical offset(inclusive) at which to start mapping(in).  */
+  uint64_t fm_start;
+
+  /* Logical length of mapping which userspace wants(in).  */
+  uint64_t fm_length;
+
+  /* FIEMAP_FLAG_* flags for request(in/out).  */
+  uint32_t fm_flags;
+
+  /* Number of extents that were mapped(out).  */
+  uint32_t fm_mapped_extents;
+
+  /* Size of fm_extents array(in).  */
+  uint32_t fm_extent_count;
+
+  uint32_t fm_reserved;
+
+  /* Array of mapped extents(out).  */
+  struct fiemap_extent fm_extents[0];
+};
+
+/* The maximum offset can be mapped for a file.  */
+# define FIEMAP_MAX_OFFSET       (~0ULL)
+
+/* Sync file data before map.  */
+# define FIEMAP_FLAG_SYNC        0x00000001
+
+/* Map extented attribute tree.  */
+# define FIEMAP_FLAG_XATTR       0x00000002
+
+# define FIEMAP_FLAGS_COMPAT     (FIEMAP_FLAG_SYNC | FIEMAP_FLAG_XATTR)
+
+/* Last extent in file.  */
+# define FIEMAP_EXTENT_LAST              0x00000001
+
+/* Data location unknown.  */
+# define FIEMAP_EXTENT_UNKNOWN           0x00000002
+
+/* Location still pending, Sets EXTENT_UNKNOWN.  */
+# define FIEMAP_EXTENT_DELALLOC          0x00000004
+
+/* Data can not be read while fs is unmounted.  */
+# define FIEMAP_EXTENT_ENCODED           0x00000008
+
+/* Data is encrypted by fs.  Sets EXTENT_NO_BYPASS.  */
+# define FIEMAP_EXTENT_DATA_ENCRYPTED    0x00000080
+
+/* Extent offsets may not be block aligned.  */
+# define FIEMAP_EXTENT_NOT_ALIGNED       0x00000100
+
+/* Data mixed with metadata.  Sets EXTENT_NOT_ALIGNED.  */
+# define FIEMAP_EXTENT_DATA_INLINE       0x00000200
+
+/* Multiple files in block.  Set EXTENT_NOT_ALIGNED.  */
+# define FIEMAP_EXTENT_DATA_TAIL         0x00000400
+
+/* Space allocated, but not data (i.e. zero).  */
+# define FIEMAP_EXTENT_UNWRITTEN         0x00000800
+
+/* File does not natively support extents.  Result merged for efficiency.  */
+# define FIEMAP_EXTENT_MERGED		0x00001000
+
+/* Space shared with other files.  */
+# define FIEMAP_EXTENT_SHARED            0x00002000
+
+#endif