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/dummy-include/string.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) create mode 100644 usr/dummy-include/string.h (limited to 'usr/dummy-include/string.h') diff --git a/usr/dummy-include/string.h b/usr/dummy-include/string.h new file mode 100644 index 000000000..e059808d3 --- /dev/null +++ b/usr/dummy-include/string.h @@ -0,0 +1,12 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef _DUMMY_STRING_H +#define _DUMMY_STRING_H + +#include + +#define memset(_s, _c, _n) __builtin_memset(_s, _c, _n) +#define memcpy(_dest, _src, _n) __builtin_memcpy(_dest, _src, _n) + +#define strlen(_s) __builtin_strlen(_s) + +#endif /* _DUMMY_STRING_H */ -- cgit v1.3.1