Jeff Liu
2011-Aug-26 09:43 UTC
bug#8061: Introduce SEEK_DATA/SEEK_HOLE to extent_scan module
Dear All,
As the SEEK_HOLE/SEEK_DATA has been implemented on Btrfs in 3.1.0+ and
Glibc, I have worked out a new version for your guys review.
Changes:
=====extent_scan.[c|h]:
1. add a function pointer to "struct extent_scan":
/* Scan method. */
bool (*extent_scan) (struct extent_scan *scan);
2. add a structure item to indicate seek back issue maybe occurred:
/* Failed to seek back to position 0 or not. */
bool seek_back_failed;
If the file system support SEEK_HOLE, the file offset will pointed to
somewhere > 0, so need to
seek back to the beginning after support_seek_hole() checking for the
proceeding extent scan.
3. rename extent_scan to fiemap_extent_scan.
4. add a new seek_extent_scan method.
5. add a new method to check SEEK stuff is supported or not.
if the underlaying file system support SEEK_HOLE, assign
seek_extent_scan to scan->extent_scan, or else, fiemap_extent_scan()
will be assigned to it.
copy.c:
1. pass src_total_size to extent_scan_init ().
2. for the first round extent scan, we need to seek back to position 0
too, if the data extent is started at the beginning of source file.
Tested:
=====1. make syntax-check.
2. verify a copied sparse file with 4697 extents on btrfs
jeff@pibroch:~/gnu/coreutils$ python -c
"f=open(''/btrfs/sparse_test'',
''w''); [(f.seek(x) or f.write(str(x))) for x in range(1,
1000000000,
99999)]; f.close()"
jeff@pibroch:~/gnu/coreutils$ ./src/cp --sparse=always
/btrfs/sparse_test /btrfs/sp.seek
jeff@pibroch:~/gnu/coreutils$ cmp /btrfs/sparse_test /btrfs/sp.seek
jeff@pibroch:~/gnu/coreutils$ echo $?
0
Also, the previous patch was developed on Solaris ZFS, but my test env
was lost now. :( so anyone can help testing it on ZFS would be
appreciated!!
From 5892744f977a06b5557042682c39fd007eec8030 Mon Sep 17 00:00:00 2001
From: Jie Liu <jeff.liu@oracle.com>
Date: Fri, 26 Aug 2011 17:11:33 +0800
Subject: [PATCH 1/1] copy: add SEEK_DATA/SEEK_HOLE support to
extent_scan module
* src/extent_scan.h: introduce src_total_size to struct extent_info, we
need it for lseek(2) iteration, add seek_back_failed to indicate that the
seek back to position 0 failed in seek captical check or not, and it can
be used for further debugging IMHO.
add bool (*extent_scan) (struct extent_scan *scan) to switch the scan
method.
* src/extent_scan.c: implement a new seek_scan_read() through SEEK_DATA
and SEEK_HOLE.
* src/copy.c: a few code changes according to the new extent call interface.
Signed-off-by: Jie Liu <jeff.liu@oracle.com>
---
src/copy.c | 26 +++++++++-
src/extent-scan.c | 149
++++++++++++++++++++++++++++++++++++++++++++++++++--
src/extent-scan.h | 16 +++++-
3 files changed, 183 insertions(+), 8 deletions(-)
diff --git a/src/copy.c b/src/copy.c
index bc4d7bd..c5e8714 100644
--- a/src/copy.c
+++ b/src/copy.c
@@ -309,7 +309,18 @@ extent_copy (int src_fd, int dest_fd, char *buf,
size_t buf_size,
We may need this at the end, for a final ftruncate. */
off_t dest_pos = 0;
- extent_scan_init (src_fd, &scan);
+ bool init_ok = extent_scan_init (src_fd, src_total_size, &scan);
+ /* If the underlaying file system support SEEK_HOLE, but failed
+ to seek back to position 0 after the initial seek checking,
+ let extent copy failure in this case. */
+ if (! init_ok)
+ {
+ if (scan.seek_back_failed)
+ error (0, errno,
+ _("%s: extent_scan_init () failed, cannot seek back to
position 0"),
+ quote (src_name));
+ return false;
+ }
*require_normal_copy = false;
bool wrote_hole_at_eof = true;
@@ -356,6 +367,19 @@ extent_copy (int src_fd, int dest_fd, char *buf,
size_t buf_size,
wrote_hole_at_eof = false;
+ /* For the first round scan, if the data extent start at the
+ beginning, and the current file pointer is not at position
+ 0, set it back first, otherwise, we''ll read from
undesired
+ file offset. */
+ if (ext_start == 0 && lseek (src_fd, 0, SEEK_CUR) != 0)
+ {
+ if (lseek (src_fd, 0, SEEK_SET) < 0)
+ {
+ error (0, errno, _("cannot lseek %s"), quote
(src_name));
+ return false;
+ }
+ }
+
if (hole_size)
{
if (lseek (src_fd, ext_start, SEEK_SET) < 0)
diff --git a/src/extent-scan.c b/src/extent-scan.c
index 37445b8..c835b63 100644
--- a/src/extent-scan.c
+++ b/src/extent-scan.c
@@ -27,6 +27,12 @@
#include "fiemap.h"
#include "xstrtol.h"
+#ifndef SEEK_DATA
+# define SEEK_DATA 3 /* Seek to next data. */
+#endif
+#ifndef SEEK_HOLE
+# define SEEK_HOLE 4 /* Seek to next hole. */
+#endif
/* Work around Linux kernel issues on BTRFS and EXT4 before 2.6.39.
FIXME: remove in 2013, or whenever we''re pretty confident
@@ -65,10 +71,48 @@ extent_need_sync (void)
#endif
}
+static bool
+support_seek_hole (struct extent_scan *scan)
+{
+ off_t hole_pos;
+
+# ifdef _PC_MIN_HOLE_SIZE
+ /* To determine if the underlaying file system support
+ SEEK_HOLE, if not, fall back to fiemap extent scan or
+ the standard copy. */
+ if (fpathconf (scan->fd, _PC_MIN_HOLE_SIZE) < 0)
+ return false;
+# endif
+
+ /* Inspired by STAR, If we have been compiled on an OS that
+ supports SEEK_HOLE but run on an OS that does not support
+ SEEK_HOLE, we get EINVAL. If the underlying file system
+ does not support the SEEK_HOLE call, we get ENOTSUP, fall
+ back to the fiemap scan or standard copy in either case. */
+ hole_pos = lseek (scan->fd, (off_t) 0, SEEK_HOLE);
+ if (hole_pos < 0)
+ {
+ if (errno == EINVAL || errno == ENOTSUP)
+ return false;
+ }
+
+ /* Seek back to position 0 first if we detected a real hole. */
+ if (hole_pos > 0)
+ {
+ if (lseek (scan->fd, (off_t) 0, SEEK_SET) != 0)
+ {
+ scan->seek_back_failed = true;
+ return false;
+ }
+ }
+
+ return true;
+}
+
/* Allocate space for struct extent_scan, initialize the entries if
necessary and return it as the input argument of
extent_scan_read(). */
-extern void
-extent_scan_init (int src_fd, struct extent_scan *scan)
+extern bool
+extent_scan_init (int src_fd, size_t src_total_size, struct extent_scan
*scan)
{
scan->fd = src_fd;
scan->ei_count = 0;
@@ -76,17 +120,110 @@ extent_scan_init (int src_fd, struct extent_scan
*scan)
scan->scan_start = 0;
scan->initial_scan_failed = false;
scan->hit_final_extent = false;
- scan->fm_flags = extent_need_sync () ? FIEMAP_FLAG_SYNC : 0;
+ scan->seek_back_failed = false;
+
+ if (support_seek_hole (scan))
+ {
+ scan->src_total_size = src_total_size;
+ scan->extent_scan = seek_extent_scan;
+ }
+ else
+ {
+ /* The underlying file system support SEEK_HOLE, but failed
+ to seek back to position 0 after seek checking, Oops! */
+ if (scan->seek_back_failed)
+ return false;
+
+ scan->extent_scan = fiemap_extent_scan;
+ scan->fm_flags = extent_need_sync () ? FIEMAP_FLAG_SYNC : 0;
+ }
+
+ return true;
+}
+
+extern inline bool
+extent_scan_read (struct extent_scan *scan)
+{
+ return scan->extent_scan (scan);
+}
+
+extern bool
+seek_extent_scan (struct extent_scan *scan)
+{
+ off_t data_pos, hole_pos;
+ union { struct extent_info ei; char c[4096]; } extent_buf;
+ struct extent_info *ext_info = &extent_buf.ei;
+ enum { count = (sizeof extent_buf / sizeof *ext_info) };
+ verify (count != 0);
+
+ memset (&extent_buf, 0, sizeof extent_buf);
+
+ unsigned int i = 0;
+ /* If lseek(2) failed and the errno is set to ENXIO, for
+ SEEK_DATA there are no more data regions past the supplied
+ offset. For SEEK_HOLE, there are no more holes past the
+ supplied offset. Set scan->hit_final_extent to true for
+ either case. */
+ do {
+ data_pos = lseek (scan->fd, scan->scan_start, SEEK_DATA);
+ if (data_pos < 0)
+ {
+ if (errno == ENXIO)
+ {
+ scan->hit_final_extent = true;
+ return true;
+ }
+ return false;
+ }
+
+ /* We hit the final extent if the data offset is equal to
+ the source file size. */
+ if (data_pos == scan->src_total_size)
+ {
+ scan->hit_final_extent = true;
+ break;
+ }
+
+ hole_pos = lseek (scan->fd, data_pos, SEEK_HOLE);
+ if (hole_pos < 0)
+ {
+ if (errno != ENXIO)
+ return false;
+ else
+ {
+ scan->hit_final_extent = true;
+ return true;
+ }
+ }
+
+ ext_info[i].ext_logical = data_pos;
+ ext_info[i].ext_length = hole_pos - data_pos;
+ scan->scan_start = hole_pos;
+ ++i;
+ } while (scan->scan_start < scan->src_total_size && i <
count);
+
+ scan->ei_count = i;
+ scan->ext_info = xnmalloc (scan->ei_count, sizeof (struct
extent_info));
+
+ for (i = 0; i < scan->ei_count; i++)
+ {
+ assert (ext_info[i].ext_logical <= OFF_T_MAX);
+
+ scan->ext_info[i].ext_logical = ext_info[i].ext_logical;
+ scan->ext_info[i].ext_length = ext_info[i].ext_length;
+ }
+
+ return true;
}
-#ifdef __linux__
+#if defined __linux__
# ifndef FS_IOC_FIEMAP
# define FS_IOC_FIEMAP _IOWR (''f'', 11, struct fiemap)
# endif
/* Call ioctl(2) with FS_IOC_FIEMAP (available in linux 2.6.27) to
obtain a map of file extents excluding holes. */
extern bool
-extent_scan_read (struct extent_scan *scan)
+fiemap_extent_scan (struct extent_scan *scan)
{
unsigned int si = 0;
struct extent_info *last_ei IF_LINT ( = scan->ext_info);
@@ -212,7 +349,7 @@ extent_scan_read (struct extent_scan *scan)
}
#else
extern bool
-extent_scan_read (struct extent_scan *scan ATTRIBUTE_UNUSED)
+fiemap_extent_scan (struct extent_scan *scan ATTRIBUTE_UNUSED)
{
scan->initial_scan_failed = true;
errno = ENOTSUP;
diff --git a/src/extent-scan.h b/src/extent-scan.h
index 5b4ded5..e751810 100644
--- a/src/extent-scan.h
+++ b/src/extent-scan.h
@@ -38,6 +38,9 @@ struct extent_scan
/* File descriptor of extent scan run against. */
int fd;
+ /* Source file size, i.e, (struct stat) &statbuf.st_size. */
+ size_t src_total_size;
+
/* Next scan start offset. */
off_t scan_start;
@@ -47,6 +50,9 @@ struct extent_scan
/* How many extent info returned for a scan. */
uint32_t ei_count;
+ /* Failed to seek back to position 0 or not. */
+ bool seek_back_failed;
+
/* If true, fall back to a normal copy, either set by the
failure of ioctl(2) for FIEMAP or lseek(2) with SEEK_DATA. */
bool initial_scan_failed;
@@ -54,14 +60,22 @@ struct extent_scan
/* If true, the total extent scan per file has been finished. */
bool hit_final_extent;
+ /* Scan method. */
+ bool (*extent_scan) (struct extent_scan *scan);
+
/* Extent information: a malloc''d array of ei_count structs. */
struct extent_info *ext_info;
};
-void extent_scan_init (int src_fd, struct extent_scan *scan);
+bool extent_scan_init (int src_fd, size_t src_total_size,
+ struct extent_scan *scan);
bool extent_scan_read (struct extent_scan *scan);
+bool fiemap_extent_scan (struct extent_scan *scan);
+
+bool seek_extent_scan (struct extent_scan *scan);
+
static inline void
extent_scan_free (struct extent_scan *scan)
{
--
1.7.4.1
Thanks,
-Jeff
On 04/19/2011 04:51 PM, Jeff liu wrote:>> Hi All,
>>
>> Please ignore the current patch, I will submit another patch with a few
fixes soon.
> Now the new patch set coming,
>
> In previous post, I have tried to change the extent_scan_init() interface
by adding a new argument to indicate the source file size,
> this will reduce the overhead of call fstat(2) in extent_scan_read(),
since the file size is definitely needed for SEEK* stuff, however, the file size
is redundant for FIEMAP.
> so I changed my idea to keep extent_scan_init() as before, instead, to
retrieve the file size in extent_scan_read() when launching the first scan, one
benefit is, there is nothing need to
> be modified in extent_copy() for this patch.
>
> Tests:
> ===> A new test sparse-lseek was introduced in this post, it make use of
the sparse file generation function in Perl, and do `cmp` against the target
copied file.
> I have also took a look at the `sdb` utility shipped with ZFS, but did not
found any interesting stuff can be used for this test.
>
> Test run passed on my environment as below,
>
> bash-3.00# make check TESTS=cp/sparse-lseek VERBOSE=yes
> make check-TESTS
> make[1]: Entering directory `/coreutils/tests''
> make[2]: Entering directory `/coreutils/tests''
> PASS: cp/sparse-lseek
> ============> 1 test passed
> ============> make[2]: Leaving directory `/coreutils/tests''
> make[1]: Leaving directory `/coreutils/tests''
> GEN vc_exe_in_TESTS
> No differences encountered
>
> Manual tests:
> ==========> 1. Ensure trailing blanks, test 0 size sparse file,
non-sparse file, sparse file with hole start and hole end.
> 2. make syntax-check failed, I have no idea of this issue at the moment, I
also tried to run make distcheck, looks the package building, install and
uninstall procedures all passed,
> but it also failed at the final stage, am I missing something here?
>
> The logs which were shown as following,
> bash-3.00# make syntax-check
> GFDL_version
> awk: syntax error near line 1
> awk: bailing out near line 1
> make: *** [sc_GFDL_version.z] Error 2
>
> make distcheck:
> =============> ......
> make[1]: Entering directory `/coreutils''
> GEN check-ls-dircolors
> make my-distcheck
> make[2]: Entering directory `/coreutils''
> make syntax-check
> make[3]: Entering directory `/coreutils''
> GFDL_version
> awk: syntax error near line 1
> awk: bailing out near line 1
> make[3]: *** [sc_GFDL_version.z] Error 2
> make[3]: Leaving directory `/coreutils''
> make[2]: *** [my-distcheck] Error 2
> make[2]: Leaving directory `/coreutils''
> make[1]: *** [distcheck-hook] Error 2
> make[1]: Leaving directory `/coreutils''
> make: *** [distcheck] Error 1
>
>
>
> Below is the revised patch,
>
> From 4f966c1fe6226f3f711faae120cd8bea78e722b8 Mon Sep 17 00:00:00 2001
> From: Jie Liu<jeff.liu@oracle.com>
> Date: Tue, 19 Apr 2011 15:24:50 -0700
> Subject: [PATCH 1/1] copy: add SEEK_DATA/SEEK_HOLE support to extent_scan
module
>
> * src/extent_scan.h: introduce src_total_size to struct extent_info, we
> need it for lseek(2) iteration.
> * src/extent_scan.c: implement a new extent_scan_read() through SEEK_DATA
> and SEEK_HOLE if those stuff are supported.
> * tests/cp/sparse-lseek: add a new test for lseek(2) extent copy.
>
> Signed-off-by: Jie Liu<jeff.liu@oracle.com>
> ---
> src/extent-scan.c | 119
+++++++++++++++++++++++++++++++++++++++++++++++++
> src/extent-scan.h | 5 ++
> tests/Makefile.am | 1 +
> tests/cp/sparse-lseek | 56 +++++++++++++++++++++++
> 4 files changed, 181 insertions(+), 0 deletions(-)
> create mode 100755 tests/cp/sparse-lseek
>
> diff --git a/src/extent-scan.c b/src/extent-scan.c
> index da7eb9d..a54eca0 100644
> --- a/src/extent-scan.c
> +++ b/src/extent-scan.c
> @@ -17,7 +17,9 @@
> Written by Jie Liu (jeff.liu@oracle.com). */
>
> #include<config.h>
> +#include<fcntl.h>
> #include<sys/types.h>
> +#include<sys/stat.h>
> #include<sys/ioctl.h>
> #include<sys/utsname.h>
> #include<assert.h>
> @@ -71,6 +73,9 @@ extent_scan_init (int src_fd, struct extent_scan *scan)
> scan->initial_scan_failed = false;
> scan->hit_final_extent = false;
> scan->fm_flags = extent_need_sync () ? FIEMAP_FLAG_SYNC : 0;
> +#if defined (SEEK_DATA)&& defined (SEEK_HOLE)
> + scan->src_total_size = 0;
> +#endif
> }
>
> #ifdef __linux__
> @@ -204,6 +209,120 @@ extent_scan_read (struct extent_scan *scan)
>
> return true;
> }
> +#elif defined (SEEK_HOLE)&& defined (SEEK_DATA)
> +extern bool
> +extent_scan_read (struct extent_scan *scan)
> +{
> + off_t data_pos, hole_pos;
> + union { struct extent_info ei; char c[4096]; } extent_buf;
> + struct extent_info *ext_info =&extent_buf.ei;
> + enum { count = (sizeof extent_buf / sizeof *ext_info) };
> + verify (count != 0);
> +
> + memset (&extent_buf, 0, sizeof extent_buf);
> +
> + if (scan->scan_start == 0)
> + {
> +# ifdef _PC_MIN_HOLE_SIZE
> + /* To determine if the underlaying file system support
> + SEEK_HOLE. If not, fall back to the standard copy. */
> + if (fpathconf (scan->fd, _PC_MIN_HOLE_SIZE)< 0)
> + {
> + scan->initial_scan_failed = true;
> + return false;
> + }
> +# endif
> +
> + /* If we have been compiled on an OS that supports SEEK_HOLE
> + but run on an OS that does not support SEEK_HOLE, we get
> + EINVAL. If the underlying file system does not support the
> + SEEK_HOLE call, we get ENOTSUP, setting initial_scan_failed
> + to true to fall back to the standard copy in either case. */
> + hole_pos = lseek (scan->fd, (off_t) 0, SEEK_HOLE);
> + if (hole_pos< 0)
> + {
> + if (errno == EINVAL || errno == ENOTSUP)
> + scan->initial_scan_failed = true;
> + return false;
> + }
> +
> + /* Seek back to position 0 first. */
> + if (hole_pos> 0)
> + {
> + if (lseek (scan->fd, (off_t) 0, SEEK_SET)< 0)
> + return false;
> + }
> +
> + struct stat sb;
> + if (fstat (scan->fd,&sb)< 0)
> + return false;
> +
> + /* This is definitely not a sparse file, we treat it as a big
extent. */
> + if (hole_pos>= sb.st_size)
> + {
> + scan->ei_count = 1;
> + scan->ext_info = xnmalloc (scan->ei_count, sizeof (struct
extent_info));
> + scan->ext_info[0].ext_logical = 0;
> + scan->ext_info[0].ext_length = sb.st_size;
> + scan->hit_final_extent = true;
> + return true;
> + }
> + scan->src_total_size = sb.st_size;
> + }
> +
> + unsigned int i = 0;
> + /* If lseek(2) failed and the errno is set to ENXIO, for
> + SEEK_DATA there are no more data regions past the supplied
> + offset. For SEEK_HOLE, there are no more holes past the
> + supplied offset. Set scan->hit_final_extent to true in
> + either case. */
> + while (scan->scan_start< scan->src_total_size&& i<
count)
> + {
> + data_pos = lseek (scan->fd, scan->scan_start, SEEK_DATA);
> + if (data_pos< 0)
> + {
> + if (errno == ENXIO)
> + {
> + scan->hit_final_extent = true;
> + break;
> + }
> + return false;
> + }
> +
> + hole_pos = lseek (scan->fd, data_pos, SEEK_HOLE);
> + if (hole_pos< 0)
> + {
> + if (errno == ENXIO)
> + {
> + scan->hit_final_extent = true;
> + hole_pos = scan->src_total_size;
> + if (data_pos< hole_pos)
> + goto preserve_ext_info;
> + break;
> + }
> + return false;
> + }
> +
> +preserve_ext_info:
> + ext_info[i].ext_logical = data_pos;
> + ext_info[i].ext_length = hole_pos - data_pos;
> + scan->scan_start = hole_pos;
> + ++i;
> + }
> +
> + scan->ei_count = i;
> + scan->ext_info = xnmalloc (scan->ei_count, sizeof (struct
extent_info));
> +
> + for (i = 0; i< scan->ei_count; i++)
> + {
> + assert (ext_info[i].ext_logical<= OFF_T_MAX);
> +
> + scan->ext_info[i].ext_logical = ext_info[i].ext_logical;
> + scan->ext_info[i].ext_length = ext_info[i].ext_length;
> + }
> +
> + return (lseek (scan->fd, (off_t) 0, SEEK_SET)< 0) ? false : true;
> +}
> #else
> extern bool
> extent_scan_read (struct extent_scan *scan ATTRIBUTE_UNUSED)
> diff --git a/src/extent-scan.h b/src/extent-scan.h
> index 5b4ded5..4fc05c6 100644
> --- a/src/extent-scan.h
> +++ b/src/extent-scan.h
> @@ -38,6 +38,11 @@ struct extent_scan
> /* File descriptor of extent scan run against. */
> int fd;
>
> +# if defined (SEEK_DATA)&& defined (SEEK_HOLE)
> + /* Source file size, i.e, (struct stat)&statbuf.st_size. */
> + size_t src_total_size;
> +#endif
> +
> /* Next scan start offset. */
> off_t scan_start;
>
> diff --git a/tests/Makefile.am b/tests/Makefile.am
> index 685eb52..6c596b9 100644
> --- a/tests/Makefile.am
> +++ b/tests/Makefile.am
> @@ -28,6 +28,7 @@ root_tests = \
> cp/cp-mv-enotsup-xattr \
> cp/capability \
> cp/sparse-fiemap \
> + cp/sparse-lseek \
> dd/skip-seek-past-dev \
> install/install-C-root \
> ls/capability \
> diff --git a/tests/cp/sparse-lseek b/tests/cp/sparse-lseek
> new file mode 100755
> index 0000000..5b8f2c1
> --- /dev/null
> +++ b/tests/cp/sparse-lseek
> @@ -0,0 +1,56 @@
> +#!/bin/sh
> +# Test cp --sparse=always through lseek(SEEK_DATA/SEEK_HOLE) copy
> +
> +# Copyright (C) 2010-2011 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/>.
> +
> +. "${srcdir=.}/init.sh"; path_prepend_ ../src
> +print_ver_ cp
> +$PERL -e 1 || skip_test_ ''you lack perl''
> +
> +zfsdisk=diskX
> +zfspool=seektest
> +
> +require_root_
> +
> +cwd=$PWD
> +cleanup_() { zpool destroy $zfspool; }
> +
> +skip=0
> +mkfile 128m "$cwd/$zfsdisk" || skip=1
> +
> +# Check if the seektest pool is already exists
> +zpool list $zfspool 2>/dev/null&&
> + skip_test_ "$zfspool already exists"
> +
> +# Create pool and verify if it is mounted automatically
> +zpool create $zfspool "$cwd/$zfsdisk" || skip=1
> +zpool list $zfspool>/dev/null || skip=1
> +
> +test $skip = 1&& skip_test_ "insufficient ZFS support"
> +
> +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$n) or die
"$!"}''> /$zfspool/j1 || fail=1
> +
> + cp --sparse=always /$zfspool/j1 /$zfspool/j2 || fail=1
> + cmp /$zfspool/j1 /$zfspool/j2 || fail=1
> + test $fail = 1&& break 2
> + done
> +done
> +
> +Exit $fail