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 --- scripts/checker-valid.sh | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) create mode 100755 scripts/checker-valid.sh (limited to 'scripts/checker-valid.sh') diff --git a/scripts/checker-valid.sh b/scripts/checker-valid.sh new file mode 100755 index 000000000..625a789ed --- /dev/null +++ b/scripts/checker-valid.sh @@ -0,0 +1,19 @@ +#!/bin/sh -eu +# SPDX-License-Identifier: GPL-2.0 + +[ ! -x "$(command -v "$1")" ] && exit 1 + +tmp_file=$(mktemp) +trap "rm -f $tmp_file" EXIT + +cat << EOF >$tmp_file +static inline int u(const int *q) +{ + __typeof_unqual__(*q) v = *q; + return v; +} +EOF + +# sparse happily exits with 0 on error so validate +# there is none on stderr. Use awk as grep is a pain with sh -e +$@ $tmp_file 2>&1 | awk -v c=1 '/error/{c=0}END{print c}' -- cgit v1.3.1