From a0e9478ca30b3eb24e58e6cd6da68d1b8933e221 Mon Sep 17 00:00:00 2001 From: GNU Libc Maintainers Date: Sat, 2 Oct 2021 13:47:40 +0100 Subject: [PATCH] git-holes Committed for glibc 2.32 commit 3f6e4fc4542b5b881906bf2f83eb4b8359b0dcd4 Author: Samuel Thibault Date: Thu Jun 4 20:52:19 2020 +0200 support: Fix detecting hole support on >2KB-block filesystems When detecting hole support, we write at 16MiB, and filesystems will typically need two levels of data to record that. On filesystems with 8KB block, the two indirection blocks will require a total of 16KB overhead, thus 32 512-byte sectors. Spotted on GNU/Hurd with a 4KB blocks filesystem, but also happens on Linux with 4KB or 8KB blocks filesystems. * support/support_descriptor_supports_holes.c (support_descriptor_supports_holes): Set block_headroom to 32. Gbp-Pq: Topic hurd-i386 Gbp-Pq: Name git-holes.diff --- support/support_descriptor_supports_holes.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/support/support_descriptor_supports_holes.c b/support/support_descriptor_supports_holes.c index fc2aa76f1..d3d5d3a93 100644 --- a/support/support_descriptor_supports_holes.c +++ b/support/support_descriptor_supports_holes.c @@ -34,8 +34,10 @@ support_descriptor_supports_holes (int fd) write_offset = 16 * 1024 * 1024, /* Our write may add this number of additional blocks (see - block_limit below). */ - block_headroom = 8, + block_limit below): writing at offset 16M can require two data block + indirections, each of which can be as large as 8KB on ext2, thus 32 + 512B sectors. */ + block_headroom = 32, }; struct stat64 st; -- 2.30.2