This patch is needed in order to build Guix on a Btrfs file system. From da922703282b0d3b8837a99a9c7fdd32f1d20d49 Mon Sep 17 00:00:00 2001 From: Mark H Weaver Date: Tue, 9 Jan 2018 20:16:14 -0500 Subject: [PATCH] Remove nonportable check for files containing only zeroes. This check benefitted only one unlikely case (large files containing only zeroes, on systems that do not support SEEK_HOLE) and was based on an assumption about file system behavior that is not mandated by POSIX and no longer holds in practice, namely that for sufficiently large files, (st_blocks == 0) implies that the file contains only zeroes. Examples of file systems that violate this assumption include Linux's /proc file system and Btrfs. * src/sparse.c (sparse_scan_file_wholesparse): Remove this function. (sparse_scan_file_seek): Remove the initial check for files containing only zeroes. --- src/sparse.c | 24 ------------------------ 1 file changed, 24 deletions(-) diff --git a/src/sparse.c b/src/sparse.c index d41c0ea..3de6560 100644 --- a/src/sparse.c +++ b/src/sparse.c @@ -261,26 +261,6 @@ sparse_scan_file_raw (struct tar_sparse_file *file) return tar_sparse_scan (file, scan_end, NULL); } -static bool -sparse_scan_file_wholesparse (struct tar_sparse_file *file) -{ - struct tar_stat_info *st = file->stat_info; - struct sp_array sp = {0, 0}; - - /* Note that this function is called only for truly sparse files of size >= 1 - block size (checked via ST_IS_SPARSE before). See the thread - http://www.mail-archive.com/bug-tar@gnu.org/msg04209.html for more info */ - if (ST_NBLOCKS (st->stat) == 0) - { - st->archive_file_size = 0; - sp.offset = st->stat.st_size; - sparse_add_map (st, &sp); - return true; - } - - return false; -} - #ifdef SEEK_HOLE /* Try to engage SEEK_HOLE/SEEK_DATA feature. */ static bool @@ -343,10 +323,6 @@ sparse_scan_file_seek (struct tar_sparse_file *file) static bool sparse_scan_file (struct tar_sparse_file *file) { - /* always check for completely sparse files */ - if (sparse_scan_file_wholesparse (file)) - return true; - switch (hole_detection) { case HOLE_DETECTION_DEFAULT: -- 2.15.1 owrap'>AgeCommit message (Expand)Author 2020-06-24nix: Tweak .gitignore files....Remove .gitignore entries where they match source files that are tracked in Git. This is relevant to me at least, as some code searching tools use .gitignore files and will ignore matched files. Christopher Baines 2019-11-26daemon: boost::format: Fix typo "referred"....* nix/boost/format/exceptions.hpp (too_few_args): Fix typo. (too_many_args): Fix typo. Signed-off-by: Ludovic Courtès <ludo@gnu.org> Vagrant Cascadian