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 --- tools/include/asm-generic/bitops.h | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) create mode 100644 tools/include/asm-generic/bitops.h (limited to 'tools/include/asm-generic/bitops.h') diff --git a/tools/include/asm-generic/bitops.h b/tools/include/asm-generic/bitops.h new file mode 100644 index 000000000..9ab313e93 --- /dev/null +++ b/tools/include/asm-generic/bitops.h @@ -0,0 +1,31 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __TOOLS_ASM_GENERIC_BITOPS_H +#define __TOOLS_ASM_GENERIC_BITOPS_H + +/* + * tools/ copied this from include/asm-generic/bitops.h, bit by bit as it needed + * some functions. + * + * For the benefit of those who are trying to port Linux to another + * architecture, here are some C-language equivalents. You should + * recode these in the native assembly language, if at all possible. + * + * C language equivalents written by Theodore Ts'o, 9/26/92 + */ + +#include +#include +#include +#include +#include + +#ifndef _TOOLS_LINUX_BITOPS_H_ +#error only can be included directly +#endif + +#include + +#include +#include + +#endif /* __TOOLS_ASM_GENERIC_BITOPS_H */ -- cgit v1.3.1