File coreutils-9.8-tail-large-num-of-files.patch of Package coreutils

Upstream patch on top of v9.8 for 'tail -nN' for larger N.
Remove for next release >v9.8 again.
Tracked at Fedora as: rh#2398008

Upstream patch:
https://cgit.git.sv.gnu.org/cgit/coreutils.git/commit/?id=914972e80dbf82aac9ffe3

  tail: fix tailing larger number of lines in regular files

  * src/tail.c (file_lines): Seek to the previous block instead of the
  beginning (or a little before) of the block that was just scanned.
  Otherwise, the same block is read and scanned (at least partially)
  again. This bug was introduced by commit v9.7-219-g976f8abc1.
  * tests/tail/basic-seek.sh: Add a new test.
  * tests/local.mk: Reference the new test.
  * NEWS: mention the bug fix.

Applied downstream/here without the NEWS entry:

  'tail' outputs the correct number of lines again for non-small -n values.
  Previously it may have output too few lines.
  [bug introduced in coreutils-9.8]


Index: src/tail.c
===================================================================
--- src/tail.c.orig
+++ src/tail.c
@@ -596,7 +596,7 @@ file_lines (char const *prettyname, int
           goto free_buffer;
         }
 
-      pos = xlseek (fd, -bufsize, SEEK_CUR, prettyname);
+      pos = xlseek (fd, -(bufsize + bytes_read), SEEK_CUR, prettyname);
       bytes_read = read (fd, buffer, bufsize);
       if (bytes_read < 0)
         {
Index: tests/local.mk
===================================================================
--- tests/local.mk.orig
+++ tests/local.mk
@@ -179,6 +179,7 @@ all_tests =					\
   tests/tty/tty-eof.pl				\
   tests/misc/read-errors.sh			\
   tests/misc/write-errors.sh			\
+  tests/tail/basic-seek.sh			\
   tests/tail/inotify-hash-abuse.sh		\
   tests/tail/inotify-hash-abuse2.sh		\
   tests/tail/F-vs-missing.sh			\
Index: tests/tail/basic-seek.sh
===================================================================
--- /dev/null
+++ tests/tail/basic-seek.sh
@@ -0,0 +1,28 @@
+#!/bin/sh
+# Verify that tail works when seeking within a file
+
+# Copyright (C) 2025 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 <https://www.gnu.org/licenses/>.
+
+. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
+print_ver_ tail
+
+yes '=================================' |
+  head -n1K > file.in || framework_failure_
+
+# This returned 139 in coreutils v9.8
+test $(tail -n200 file.in | wc -l) = 200 || fail=1
+
+Exit $fail