kernel/linux.git/usr, branch v6.18.21

gen_init_cpio: Ignore fsync() returning EINVAL on pipes

2025-10-07T16:53:05+00:00

The reproducer: echo | ./usr/gen_init_cpio /dev/stdin > /dev/null fsync() on a pipe fd returns -EINVAL, which makes gen_init_cpio fail. Ignore -EINVAL from fsync(). Fixes: ae18b94099b0 ("gen_init_cpio: support -o parameter") Cc: David Disseldorp Cc: Nicolas Schier Signed-off-by: Dmitry Safonov Reviewed-by: David Disseldorp Link: https://patch.msgid.link/20251007-gen_init_cpio-pipe-v2-1-b098ab94b58a@arista.com Signed-off-by: Nathan Chancellor

kbuild: uapi: Strip comments before size type check

2025-10-06T18:31:19+00:00

On m68k, check_sizetypes in headers_check reports: ./usr/include/asm/bootinfo-amiga.h:17: found __[us]{8,16,32,64} type without #include This header file does not use any of the Linux-specific integer types, but merely refers to them from comments, so this is a false positive. As of commit c3a9d74ee413bdb3 ("kbuild: uapi: upgrade check_sizetypes() warning to error"), this check was promoted to an error, breaking m68k all{mod,yes}config builds. Fix this by stripping simple comments before looking for Linux-specific integer types. Signed-off-by: Geert Uytterhoeven Reviewed-by: Thomas Weißschuh Link: https://patch.msgid.link/949f096337e28d50510e970ae3ba3ec9c1342ec0.1759753998.git.geert@linux-m68k.org [nathan: Adjust comment and remove unnecessary escaping from slashes in regex] Signed-off-by: Nathan Chancellor

gen_init_cpio: add -a as reflink optimization

2025-08-20T23:02:56+00:00

As described in buffer-format.rst, the existing initramfs.c extraction logic works fine if the cpio filename field is padded out with trailing zeros, with a caveat that the padded namesize can't exceed PATH_MAX. Add filename zero-padding logic to gen_init_cpio, which can be triggered via the new -a parameter. Performance and storage utilization is improved for Btrfs and XFS workloads, as copy_file_range can reflink the entire source file into a filesystem block-size aligned destination offset within the cpio archive. Btrfs benchmarks run on 6.15.8-1-default (Tumbleweed) x86_64 host: > truncate --size=2G /tmp/backing.img > /sbin/mkfs.btrfs /tmp/backing.img ... Sector size: 4096 (CPU page size: 4096) ... > sudo mount /tmp/backing.img mnt > sudo chown $USER mnt > cd mnt mnt> dd if=/dev/urandom of=foo bs=1M count=20 && cat foo >/dev/null ... mnt> echo "file /foo foo 0755 0 0" > list mnt> perf stat -r 10 gen_init_cpio -o unaligned_btrfs list ... 0.023496 +- 0.000472 seconds time elapsed ( +- 2.01% ) mnt> perf stat -r 10 gen_init_cpio -o aligned_btrfs -a 4096 list ... 0.0010010 +- 0.0000565 seconds time elapsed ( +- 5.65% ) mnt> /sbin/xfs_io -c "fiemap -v" unaligned_btrfs unaligned_btrfs: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..40967]: 695040..736007 40968 0x1 mnt> /sbin/xfs_io -c "fiemap -v" aligned_btrfs aligned_btrfs: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..7]: 26768..26775 8 0x0 1: [8..40967]: 269056..310015 40960 0x2000 2: [40968..40975]: 26776..26783 8 0x1 mnt> /sbin/btrfs fi du unaligned_btrfs aligned_btrfs Total Exclusive Set shared Filename 20.00MiB 20.00MiB 0.00B unaligned_btrfs 20.01MiB 8.00KiB 20.00MiB aligned_btrfs XFS benchmarks run on same host: > sudo umount mnt && rm /tmp/backing.img > truncate --size=2G /tmp/backing.img > /sbin/mkfs.xfs /tmp/backing.img ... = reflink=1 ... data = bsize=4096 blocks=524288, imaxpct=25 ... > sudo mount /tmp/backing.img mnt > sudo chown $USER mnt > cd mnt mnt> dd if=/dev/urandom of=foo bs=1M count=20 && cat foo >/dev/null ... mnt> echo "file /foo foo 0755 0 0" > list mnt> perf stat -r 10 gen_init_cpio -o unaligned_xfs list ... 0.011069 +- 0.000469 seconds time elapsed ( +- 4.24% ) mnt> perf stat -r 10 gen_init_cpio -o aligned_xfs -a 4096 list ... 0.001273 +- 0.000288 seconds time elapsed ( +- 22.60% ) mnt> /sbin/xfs_io -c "fiemap -v" unaligned_xfs unaligned_xfs: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..40967]: 106176..147143 40968 0x0 1: [40968..65023]: 147144..171199 24056 0x801 mnt> /sbin/xfs_io -c "fiemap -v" aligned_xfs aligned_xfs: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..7]: 120..127 8 0x0 1: [8..40967]: 192..41151 40960 0x2000 2: [40968..40975]: 236728..236735 8 0x0 3: [40976..106495]: 236736..302255 65520 0x801 The alignment is best-effort; a stderr message is printed if alignment can't be achieved due to PATH_MAX overrun, with fallback to non-padded filename. This allows it to still be useful for opportunistic alignment, e.g. on aarch64 Btrfs with 64K block-size. Alignment failure messages provide an indicator that reordering of the cpio-manifest may be beneficial. Archive read performance for reflinked initramfs images may suffer due to the effects of fragmentation, particularly on spinning disks. To mitigate excessive fragmentation, files with lengths less than data_align aren't padded. Signed-off-by: David Disseldorp Reviewed-by: Nicolas Schier Link: https://lore.kernel.org/r/20250819032607.28727-8-ddiss@suse.de Signed-off-by: Nathan Chancellor

gen_initramfs.sh: use gen_init_cpio -o parameter

2025-08-20T23:02:56+00:00

gen_init_cpio can now write to a file directly, so use it when gen_initramfs.sh is called with -o (e.g. usr/Makefile invocation). Signed-off-by: David Disseldorp Reviewed-by: Nicolas Schier Link: https://lore.kernel.org/r/20250819032607.28727-6-ddiss@suse.de Signed-off-by: Nathan Chancellor

gen_init_cpio: avoid duplicate strlen calls

2025-08-20T23:02:56+00:00

We determine the filename length for the cpio header, so shouldn't recalculate it when writing out the filename. Signed-off-by: David Disseldorp Reviewed-by: Nicolas Schier Link: https://lore.kernel.org/r/20250819032607.28727-5-ddiss@suse.de Signed-off-by: Nathan Chancellor

gen_init_cpio: attempt copy_file_range for file data

2025-08-20T23:02:55+00:00

The copy_file_range syscall can improve copy performance by cloning extents between cpio archive source and destination files. Existing read / write based copy logic is retained for fallback in case the copy_file_range syscall is unsupported or unavailable due to cross-filesystem EXDEV, etc. Clone or reflink, as opposed to copy, of source file extents into the output cpio archive may (e.g. on Btrfs and XFS) require alignment of the output to the filesystem block size. This could be achieved by inserting padding entries into the cpio archive manifest. Signed-off-by: David Disseldorp Reviewed-by: Nicolas Schier Link: https://lore.kernel.org/r/20250819032607.28727-4-ddiss@suse.de Signed-off-by: Nathan Chancellor

gen_init_cpio: support -o parameter

2025-08-20T23:02:55+00:00

This is another preparatory change to allow for reflink-optimized cpio archives with file data written / cloned via copy_file_range(). The output file is truncated prior to write, so that it maps to usr/gen_initramfs.sh usage. It may make sense to offer an append option in future, for easier archive concatenation. Signed-off-by: David Disseldorp Reviewed-by: Nicolas Schier Link: https://lore.kernel.org/r/20250819032607.28727-3-ddiss@suse.de Signed-off-by: Nathan Chancellor

gen_init_cpio: write to fd instead of stdout stream

2025-08-20T23:02:55+00:00

In preparation for more efficient archiving using copy_file_range(), switch from writing archive data to stdout to using STDOUT_FILENO and I/O via write(), dprintf(), etc. Basic I/O error handling is added to cover cases such as ENOSPC. Partial writes are treated as errors. Signed-off-by: David Disseldorp Reviewed-by: Nicolas Schier Link: https://lore.kernel.org/r/20250819032607.28727-2-ddiss@suse.de Signed-off-by: Nathan Chancellor

kbuild: uapi: upgrade check_declarations() warning to error

2025-08-13T21:00:35+00:00

No problematic declarations exist anymore. Make sure it stays this way. Signed-off-by: Thomas Weißschuh Reviewed-by: Nicolas Schier Link: https://lore.kernel.org/r/20250813-kbuild-hdrtest-fixes-v2-5-8a7921ca3a03@linutronix.de Signed-off-by: Nathan Chancellor

kbuild: uapi: upgrade check_sizetypes() warning to error

2025-08-13T21:00:34+00:00

No problematic type usages exist anymore. Make sure it stays this way. Signed-off-by: Thomas Weißschuh Reviewed-by: Nicolas Schier Link: https://lore.kernel.org/r/20250813-kbuild-hdrtest-fixes-v2-4-8a7921ca3a03@linutronix.de Signed-off-by: Nathan Chancellor