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| author | Sergey Poznyakoff <gray@gnu.org.ua> | 2015-12-05 23:36:22 +0200 |
|---|---|---|
| committer | Sergey Poznyakoff <gray@gnu.org.ua> | 2015-12-06 00:14:55 +0200 |
| commit | b684326e6958f3a8a58202df933e925571d2fcbf (patch) | |
| tree | 44673c8beef12356b87d09bf48d42aa753f231f4 /NEWS | |
| parent | 589ba77faf60e4632771d80e2b25d9e3778d4a3f (diff) | |
| download | tar-b684326e6958f3a8a58202df933e925571d2fcbf.tar.gz | |
Use SEEK_HOLE for hole detection
Based on patch by Pavel Raiskup.
Use SEEK_HOLE/SEEK_DATA feature of lseek on systems that support
it. This can make archiving of sparse files much faster.
Implement the --hole-detection option to allow users to select
hole-detection method.
* src/common.h (hole_detection_method): New enum.
(hole_detection): New global.
* src/sparse.c (sparse_scan_file_wholesparse): New function as a
method for detecting sparse files without any data.
(sparse_scan_file_raw): Rename from sparse_scan_file; with edits.
(sparse_scan_file_seek): New function.
(sparse_scan_file): Reimplement function.
* src/tar.c: New option --hole-detection
* tests/checkseekhole.c: New file.
* tests/.gitignore: Mention two test binaries.
* tests/Makefile.am: Add new tests.
* tests/testsuite.at (AT_SEEKHOLE_PREREQ): New macro.
Include sparse06.at.
* tests/sparse06.at: New test case.
* tests/sparse02.at: Force raw hole-detection method.
* tests/sparsemv.at: Likewise.
* tests/sparsemvp.at: Likewise.
* doc/tar.1: Document --hole-detection option.
* doc/tar.texi: Document hole-detection algorithms and
command-line options.
* NEWS: Document hole-detection.
Diffstat (limited to 'NEWS')
| -rw-r--r-- | NEWS | 21 |
1 files changed, 20 insertions, 1 deletions
@@ -1,4 +1,4 @@ -GNU tar NEWS - User visible changes. 2015-11-02 +GNU tar NEWS - User visible changes. 2015-12-06 Please send GNU tar bug reports to <bug-tar@gnu.org> @@ -48,6 +48,25 @@ read from null-delimited file lists is treated as a file name. This restores the documented behavior, which was broken in version 1.27. +* Sparse file detection + +Tar now uses SEEK_DATA/SEEK_HOLE on systems that support it. This +allows for considerable speed-up in sparse-file detection. + +New option --hole-detection is provided, that allows the user to +select the algorithm used for hole detection. Available arguments +are: + + --hole-detection=seek + Use lseek(2) SEEK_DATA and SEEK_HOLE "whence" parameters. + + --hole-detection=raw + Scan entire file before storing it to determine where holes + are located. + +The default is to use "seek" whenever possible, and fall back to +"raw" otherwise. + version 1.28, 2014-07-28 |