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/Makefile.defconf | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 scripts/Makefile.defconf (limited to 'scripts/Makefile.defconf') diff --git a/scripts/Makefile.defconf b/scripts/Makefile.defconf new file mode 100644 index 000000000..a44307f08 --- /dev/null +++ b/scripts/Makefile.defconf @@ -0,0 +1,30 @@ +# SPDX-License-Identifier: GPL-2.0 +# Configuration heplers + +cmd_merge_fragments = \ + $(srctree)/scripts/kconfig/merge_config.sh \ + $4 -m -O $(objtree) $(srctree)/arch/$(SRCARCH)/configs/$2 \ + $(foreach config,$3,$(srctree)/arch/$(SRCARCH)/configs/$(config).config) + +# Creates 'merged defconfigs' +# --------------------------------------------------------------------------- +# Usage: +# $(call merge_into_defconfig,base_config,config_fragment1 config_fragment2 ...) +# +# Input config fragments without '.config' suffix +define merge_into_defconfig + $(call cmd,merge_fragments,$1,$2) + +$(Q)$(MAKE) -f $(srctree)/Makefile olddefconfig +endef + + +# Creates 'merged defconfigs without warning about overrides' +# --------------------------------------------------------------------------- +# Usage: +# $(call merge_into_defconfig_override,base_config,config_fragment1 config_fragment2 ...) +# +# Input config fragments without '.config' suffix +define merge_into_defconfig_override + $(call cmd,merge_fragments,$1,$2,-Q) + +$(Q)$(MAKE) -f $(srctree)/Makefile olddefconfig +endef -- cgit v1.3.1