From dd05add7b2b6004c5fa3a1f276f56d8668f86b65 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Sat, 26 Sep 2026 19:20:30 -0300 Subject: netfs: zero the tail of a short DIO/unbuffered read The buffered read collector zero-fills the tail of a short read that stops below the inode's i_size (netfs_clear_unread()), so a read that races an extending write still returns the expected number of bytes. The non-buffered collector path does no such thing: it just records how much was transferred. Add the same zero-fill for the non-buffered case, gated on NETFS_SREQ_CLEAR_TAIL: a subreq's source sets that flag when a short result from it is known to be safe to treat as a hole, as opposed to NETFS_SREQ_HIT_EOF, which means the read genuinely ran off the end of the file and should be reported short as-is. Only CLEAR_TAIL should zero-fill here; a real EOF must stay a real short read. No source currently sets CLEAR_TAIL on an unbuffered/DIO subrequest, so this is inert on its own -- a following change teaches cifs to set it in the one case that needs it. Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item") Reviewed-by: David Howells Reviewed-by: Namjae Jeon Signed-off-by: Paulo Alcantara Cc: Christian Brauner Cc: Matthew Wilcox Cc: Ronnie Sahlberg Cc: Shyam Prasad N Cc: Tom Talpey Cc: Bharath SM Cc: stable@vger.kernel.org --- usr/initramfs_data.S | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode 100644 usr/initramfs_data.S (limited to 'usr/initramfs_data.S') diff --git a/usr/initramfs_data.S b/usr/initramfs_data.S new file mode 100644 index 000000000..e92fb59b3 --- /dev/null +++ b/usr/initramfs_data.S @@ -0,0 +1,36 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + initramfs_data includes the compressed binary that is the + filesystem used for early user space. + Note: Older versions of "as" (prior to binutils 2.11.90.0.23 + released on 2001-07-14) did not support .incbin. + If you are forced to use older binutils than that then the + following trick can be applied to create the resulting binary: + + + ld -m elf_i386 --format binary --oformat elf32-i386 -r \ + -T initramfs_data.scr initramfs_data.cpio.gz -o initramfs_data.o + ld -m elf_i386 -r -o built-in.a initramfs_data.o + + For including the .init.ramfs sections, see include/asm-generic/vmlinux.lds. + + The above example is for i386 - the parameters vary from architectures. + Eventually look up LDFLAGS_BLOB in an older version of the + arch/$(ARCH)/Makefile to see the flags used before .incbin was introduced. + + Using .incbin has the advantage over ld that the correct flags are set + in the ELF header, as required by certain architectures. +*/ + +.section .init.ramfs,"a" +__irf_start: +.incbin "usr/initramfs_inc_data" +__irf_end: +.section .init.ramfs.info,"a" +.globl __initramfs_size +__initramfs_size: +#ifdef CONFIG_64BIT + .quad __irf_end - __irf_start +#else + .long __irf_end - __irf_start +#endif -- cgit v1.3.1