[Devel] [PATCH RHEL10 COMMIT] ext4: select LIBCRC32C

[Konstantin Khorenko <khorenko@virtuozzo.com>]

The commit is pushed to "branch-rh10-6.12.0-211.39.1.16.x.vz10-ovz" and will appear at git at bitbucket.org:openvz/vzkernel.git
after rh10-6.12.0-211.39.1.16.6.vz10
------>
commit ff1034933e199cca8a40e9156ba2cc49df80a62b
Author: Konstantin Khorenko <khorenko@virtuozzo.com>
Date:   Fri Aug 21 18:37:17 2026 +0200

    ext4: select LIBCRC32C
    
    ext4 computes its metadata checksums with crc32c().  Upstream that helper
    moved into lib/crc32.c under CONFIG_CRC32, which is what ext4 selects, but
    this tree still has the older layout where it lives in lib/libcrc32c.c
    under CONFIG_LIBCRC32C - the RHEL10.2 base carries the ext4 side of the
    conversion and not the lib one.  So a kernel with ext4 built in and
    nothing else pulling libcrc32c in does not link:
    
      ld: vmlinux.o: in function 'ext4_inode_bitmap_csum_verify':
          undefined reference to 'crc32c'
    
    Our configs get away with it because other filesystems select
    CONFIG_LIBCRC32C; plain x86_64 defconfig, which we now want to keep
    building, does not.  Select it explicitly until the lib side is caught up
    with upstream, where this select becomes redundant rather than wrong.
    
    Fixes: 9f055df11343 ("rh10: import RHEL10 kernel-6.12.0-211.16.1.el10")
    Feature: fix ms/ext4
    https://virtuozzo.atlassian.net/browse/VSTOR-134732
    Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
---
 fs/ext4/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig
index c9ca41d91a6c1..8849d297102d5 100644
--- a/fs/ext4/Kconfig
+++ b/fs/ext4/Kconfig
@@ -32,6 +32,7 @@ config EXT4_FS
 	select JBD2
 	select CRC16
 	select CRC32
+	select LIBCRC32C
 	select FS_IOMAP
 	select FS_ENCRYPTION_ALGS if FS_ENCRYPTION
 	help