build: distribute new test script, filefrag-extent-compare

* tests/Makefile.am (EXTRA_DIST): Add filefrag-extent-compare.

cfg.mk

@@ -80,7 +80,7 @@ sc_root_tests:
 	@if test -d tests \
 	      && grep check-root tests/Makefile.am>/dev/null 2>&1; then \
 	t1=sc-root.expected; t2=sc-root.actual;				\
-	grep -nl '^require_root_$$'					\
+	grep -nl '^ *require_root_$$'					\
 	  $$($(VC_LIST) tests) |sed s,tests/,, |sort > $$t1;		\
 	sed -n '/^root_tests =[	 ]*\\$$/,/[^\]$$/p'			\
 	  $(srcdir)/tests/Makefile.am					\

src/Makefile.am

@@ -145,6 +145,7 @@ noinst_HEADERS =	\
   copy.h		\
   cp-hash.h		\
   dircolors.h		\
+  fiemap.h		\
   fs.h			\
   group-list.h		\
   ls.h			\

src/copy.c

@@ -63,6 +63,10 @@
 
 #include <sys/ioctl.h>
 
+#ifndef HAVE_FIEMAP
+# include "fiemap.h"
+#endif
+
 #ifndef HAVE_FCHOWN
 # define HAVE_FCHOWN false
 # define fchown(fd, uid, gid) (-1)
@@ -149,6 +153,153 @@ clone_file (int dest_fd, int src_fd)
 #endif
 }
 
+#ifdef __linux__
+# ifndef FS_IOC_FIEMAP
+#  define FS_IOC_FIEMAP _IOWR ('f', 11, struct fiemap)
+# endif
+/* Perform a FIEMAP copy, if possible.
+   Call ioctl(2) with FS_IOC_FIEMAP (available in linux 2.6.27) to
+   obtain a map of file extents excluding holes.  This avoids the
+   overhead of detecting holes in a hole-introducing/preserving copy,
+   and thus makes copying sparse files much more efficient.  Upon a
+   successful copy, return true.  If the initial ioctl fails, set
+   *NORMAL_COPY_REQUIRED to true and return false.  Upon any other
+   failure, set *NORMAL_COPY_REQUIRED to false and return false.  */
+static bool
+fiemap_copy (int src_fd, int dest_fd, size_t buf_size,
+             off_t src_total_size, char const *src_name,
+             char const *dst_name, bool *normal_copy_required)
+{
+  bool last = false;
+  union { struct fiemap f; char c[4096]; } fiemap_buf;
+  struct fiemap *fiemap = &fiemap_buf.f;
+  struct fiemap_extent *fm_ext = &fiemap->fm_extents[0];
+  enum { count = (sizeof fiemap_buf - sizeof *fiemap) / sizeof *fm_ext };
+  verify (count != 0);
+
+  off_t last_ext_logical = 0;
+  uint64_t last_ext_len = 0;
+  uint64_t last_read_size = 0;
+  unsigned int i = 0;
+  *normal_copy_required = false;
+
+  /* This is required at least to initialize fiemap->fm_start,
+     but also serves (in mid 2010) to appease valgrind, which
+     appears not to know the semantics of the FIEMAP ioctl. */
+  memset (&fiemap_buf, 0, sizeof fiemap_buf);
+
+  do
+    {
+      fiemap->fm_length = FIEMAP_MAX_OFFSET;
+      fiemap->fm_flags = FIEMAP_FLAG_SYNC;
+      fiemap->fm_extent_count = count;
+
+      /* When ioctl(2) fails, fall back to the normal copy only if it
+         is the first time we met.  */
+      if (ioctl (src_fd, FS_IOC_FIEMAP, fiemap) < 0)
+        {
+          /* If the first ioctl fails, tell the caller that it is
+             ok to proceed with a normal copy.  */
+          if (i == 0)
+            *normal_copy_required = true;
+          else
+            {
+              /* If the second or subsequent ioctl fails, diagnose it,
+                 since it ends up causing the entire copy/cp to fail.  */
+              error (0, errno, _("%s: FIEMAP ioctl failed"), quote (src_name));
+            }
+          return false;
+        }
+
+      /* If 0 extents are returned, then more ioctls are not needed.  */
+      if (fiemap->fm_mapped_extents == 0)
+        break;
+
+      for (i = 0; i < fiemap->fm_mapped_extents; i++)
+        {
+          assert (fm_ext[i].fe_logical <= OFF_T_MAX);
+
+          off_t ext_logical = fm_ext[i].fe_logical;
+          uint64_t ext_len = fm_ext[i].fe_length;
+
+          if (lseek (src_fd, ext_logical, SEEK_SET) < 0)
+            {
+              error (0, errno, _("cannot lseek %s"), quote (src_name));
+              return false;
+            }
+
+          if (lseek (dest_fd, ext_logical, SEEK_SET) < 0)
+            {
+              error (0, errno, _("cannot lseek %s"), quote (dst_name));
+              return false;
+            }
+
+          if (fm_ext[i].fe_flags & FIEMAP_EXTENT_LAST)
+            {
+              last_ext_logical = ext_logical;
+              last_ext_len = ext_len;
+              last = true;
+            }
+
+          while (ext_len)
+            {
+              char buf[buf_size];
+
+              /* Avoid reading into the holes if the left extent
+                 length is shorter than the buffer size.  */
+              if (ext_len < buf_size)
+                buf_size = ext_len;
+
+              ssize_t n_read = read (src_fd, buf, buf_size);
+              if (n_read < 0)
+                {
+#ifdef EINTR
+                  if (errno == EINTR)
+                    continue;
+#endif
+                  error (0, errno, _("reading %s"), quote (src_name));
+                  return false;
+                }
+
+              if (n_read == 0)
+                {
+                  /* Figure out how many bytes read from the last extent.  */
+                  last_read_size = last_ext_len - ext_len;
+                  break;
+                }
+
+              if (full_write (dest_fd, buf, n_read) != n_read)
+                {
+                  error (0, errno, _("writing %s"), quote (dst_name));
+                  return false;
+                }
+
+              ext_len -= n_read;
+            }
+        }
+
+      fiemap->fm_start = fm_ext[i - 1].fe_logical + fm_ext[i - 1].fe_length;
+
+    } while (! last);
+
+  /* If a file ends up with holes, the sum of the last extent logical offset
+     and the read-returned size will be shorter than the actual size of the
+     file.  Use ftruncate to extend the length of the destination file.  */
+  if (last_ext_logical + last_read_size < src_total_size)
+    {
+      if (ftruncate (dest_fd, src_total_size) < 0)
+        {
+          error (0, errno, _("failed to extend %s"), quote (dst_name));
+          return false;
+        }
+    }
+
+  return true;
+}
+#else
+static bool fiemap_copy (ignored) { errno == ENOTSUP; return false; }
+#endif
+
 /* FIXME: describe */
 /* FIXME: rewrite this to use a hash table so we avoid the quadratic
    performance hit that's probably noticeable only on trees deeper
@@ -679,6 +830,25 @@ copy_reg (char const *src_name, char const *dst_name,
 #endif
         }
 
+      if (make_holes)
+        {
+          bool require_normal_copy;
+          /* Perform efficient FIEMAP copy for sparse files, fall back to the
+             standard copy only if the ioctl(2) fails.  */
+          if (fiemap_copy (source_desc, dest_desc, buf_size,
+                           src_open_sb.st_size, src_name,
+                           dst_name, &require_normal_copy))
+            goto preserve_metadata;
+          else
+            {
+              if (! require_normal_copy)
+                {
+                  return_val = false;
+                  goto close_src_and_dst_desc;
+                }
+            }
+        }
+
       /* If not making a sparse file, try to use a more-efficient
          buffer size.  */
       if (! make_holes)
@@ -807,6 +977,7 @@ copy_reg (char const *src_name, char const *dst_name,
         }
     }
 
+preserve_metadata:
   if (x->preserve_timestamps)
     {
       struct timespec timespec[2];

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 <stdint.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

tests/Makefile.am

@@ -10,6 +10,7 @@ EXTRA_DIST =		\
   CuTmpdir.pm		\
   check.mk		\
   envvar-check		\
+  filefrag-extent-compare \
   init.sh		\
   lang-default		\
   other-fs-tmpdir	\
@@ -25,6 +26,7 @@ root_tests =					\
   cp/special-bits				\
   cp/cp-mv-enotsup-xattr			\
   cp/capability					\
+  cp/sparse-fiemap                              \
   dd/skip-seek-past-dev				\
   install/install-C-root			\
   ls/capability					\

tests/cp/sparse-fiemap

@@ -0,0 +1,119 @@
+#!/bin/sh
+# Test cp --sparse=always through fiemap copy
+
+# Copyright (C) 2010 Free Software Foundation, Inc.
+
+# 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 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will 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, see <http://www.gnu.org/licenses/>.
+
+if test "$VERBOSE" = yes; then
+  set -x
+  cp --version
+fi
+
+. "${srcdir=.}/init.sh"; path_prepend_ ../src
+
+if df -T -t btrfs -t xfs -t ext4 -t ocfs2 . ; then
+  : # Current dir is on a partition with working extents.  Good!
+else
+  # It's not;  we need to create one, hence we need root access.
+  require_root_
+
+  cwd=$PWD
+  cleanup_() { cd /; umount "$cwd/mnt"; }
+
+  skip=0
+  # Create an ext4 loopback file system
+  dd if=/dev/zero of=blob bs=32k count=1000 || skip=1
+  mkdir mnt
+  mkfs -t ext4 -F blob ||
+    skip_test_ "failed to create ext4 file system"
+  mount -oloop blob mnt   || skip=1
+  cd mnt                  || skip=1
+  echo test > f           || skip=1
+  test -s f               || skip=1
+
+  test $skip = 1 &&
+    skip_test_ "insufficient mount/ext4 support"
+fi
+
+# Create a 1TiB sparse file
+dd if=/dev/zero of=sparse bs=1k count=1 seek=1G || framework_failure
+
+# It takes many minutes to copy this sparse file using the old method.
+# By contrast, it takes far less than 1 second using FIEMAP-copy.
+timeout 10 cp --sparse=always sparse fiemap || fail=1
+
+# Ensure that the sparse file copied through fiemap has the same size
+# in bytes as the original.
+test $(stat --printf %s sparse) = $(stat --printf %s fiemap) || fail=1
+
+# =================================================
+# Ensure that we exercise the FIEMAP-copying code enough
+# to provoke at least two iterations of the do...while loop
+# in which it calls ioctl (fd, FS_IOC_FIEMAP,...
+# This also verifies that non-trivial extents are preserved.
+
+$PERL -e 1 || skip_test_ 'skipping part of this test; you lack perl'
+
+# Extract logical block number and length pairs from filefrag -v output.
+# The initial sed is to remove the "eof" from the normally-empty "flags" field.
+# Similarly, remove flags values like "unknown,delalloc,eof".
+# That is required when that final extent has no number in the "expected" field.
+f()
+{
+  sed 's/ [a-z,][a-z,]*$//' $@ \
+    | awk '/^ *[0-9]/ {printf "%d %d ", $2 ,NF < 5 ? $NF : $5 } END {print ""}'
+}
+
+for i in $(seq 1 2 21); do
+  for j in 1 2 31 100; do
+    $PERL -e 'BEGIN { $n = '$i' * 1024; *F = *STDOUT }' \
+          -e 'for (1..'$j') { sysseek (*F, $n, 1)' \
+          -e '&& syswrite (*F, chr($_)x$n) or die "$!"}' > j1 || fail=1
+    # sync
+    cp --sparse=always j1 j2 || fail=1
+    # sync
+    # Technically we may need the 'sync' uses above, but
+    # uncommenting them makes this test take much longer.
+
+    cmp j1 j2 || fail=1
+    filefrag -v j1 | grep extent \
+      || skip_test_ 'skipping part of this test; you lack filefrag'
+
+    # Here is sample filefrag output:
+    #   $ perl -e 'BEGIN{$n=16*1024; *F=*STDOUT}' \
+    #          -e 'for (1..5) { sysseek(*F,$n,1)' \
+    #          -e '&& syswrite *F,"."x$n or die "$!"}' > j
+    #   $ filefrag -v j
+    #   File system type is: ef53
+    #   File size of j is 163840 (40 blocks, blocksize 4096)
+    #    ext logical physical expected length flags
+    #      0       4  6258884               4
+    #      1      12  6258892  6258887      4
+    #      2      20  6258900  6258895      4
+    #      3      28  6258908  6258903      4
+    #      4      36  6258916  6258911      4 eof
+    #   j: 6 extents found
+
+    # exclude the physical block numbers; they always differ
+    filefrag -v j1 > ff1 || fail=1
+    filefrag -v j2 > ff2 || fail=1
+    { f ff1; f ff2; } \
+      | $PERL $abs_top_srcdir/tests/filefrag-extent-compare \
+        || { fail=1; break; }
+  done
+  test $fail = 1 && break
+done
+
+Exit $fail

tests/filefrag-extent-compare

@@ -0,0 +1,68 @@
+eval '(exit $?0)' && eval 'exec perl -wS "$0" ${1+"$@"}'
+  & eval 'exec perl -wS "$0" $argv:q'
+    if 0;
+# Determine whether two files have the same extents by comparing
+# the logical block numbers and lengths from filefrag -v for each.
+
+# Invoke like this:
+# This helper function, f, extracts logical block number and lengths.
+# f() { awk '/^ *[0-9]/ {printf "%d %d ",$2,NF<5?$NF:$5} END {print ""}'; }
+# { filefrag -v j1 | f; filefrag -v j2 | f; } | ./filefrag-extent-compare
+
+use warnings;
+use strict;
+(my $ME = $0) =~ s|.*/||;
+
+my @line = <>;
+my $n_lines = @line;
+$n_lines == 2
+  or die "$ME: expected exactly two input lines; got $n_lines\n";
+
+my @A = split ' ', $line[0];
+my @B = split ' ', $line[1];
+@A % 2 || @B % 2
+  and die "$ME: unexpected input: odd number of numbers; expected even\n";
+
+my @a;
+my @b;
+foreach my $i (0..@A/2-1) { $a[$i] = { L_BLK => $A[2*$i], LEN => $A[2*$i+1] } };
+foreach my $i (0..@B/2-1) { $b[$i] = { L_BLK => $B[2*$i], LEN => $B[2*$i+1] } };
+
+my $i = 0;
+my $j = 0;
+while (1)
+  {
+    !defined $a[$i] && !defined $b[$j]
+      and exit 0;
+    defined $a[$i] && defined $b[$j]
+      or die "\@a and \@b have different lengths, even after adjustment\n";
+    ($a[$i]->{L_BLK} == $b[$j]->{L_BLK}
+     && $a[$i]->{LEN} == $b[$j]->{LEN})
+      and next;
+    ($a[$i]->{LEN} < $b[$j]->{LEN}
+     && exists $a[$i+1] && $a[$i]->{LEN} + $a[$i+1]->{LEN} == $b[$j]->{LEN})
+      and ++$i, next;
+    exists $b[$j+1] && $a[$i]->{LEN} == $b[$i]->{LEN} + $b[$i+1]->{LEN}
+      and ++$j, next;
+    die "differing extent:\n"
+      . "  [$i]=$a[$i]->{L_BLK} $a[$i]->{LEN}\n"
+      . "  [$j]=$b[$j]->{L_BLK} $b[$j]->{LEN}\n"
+  }
+continue
+  {
+    ++$i;
+    ++$j;
+  }
+
+### Setup "GNU" style for perl-mode and cperl-mode.
+## Local Variables:
+## mode: perl
+## perl-indent-level: 2
+## perl-continued-statement-offset: 2
+## perl-continued-brace-offset: 0
+## perl-brace-offset: 0
+## perl-brace-imaginary-offset: 0
+## perl-label-offset: -2
+## perl-extra-newline-before-brace: t
+## perl-merge-trailing-else: nil
+## End: