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.modfinal | 74 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) create mode 100644 scripts/Makefile.modfinal (limited to 'scripts/Makefile.modfinal') diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal new file mode 100644 index 000000000..01a37ec87 --- /dev/null +++ b/scripts/Makefile.modfinal @@ -0,0 +1,74 @@ +# SPDX-License-Identifier: GPL-2.0-only +# =========================================================================== +# Module final link +# =========================================================================== + +PHONY := __modfinal +__modfinal: + +include $(objtree)/include/config/auto.conf +include $(srctree)/scripts/Kbuild.include +include $(srctree)/scripts/Makefile.lib + +# find all modules listed in modules.order +modules := $(call read-file, modules.order) + +__modfinal: $(modules:%.o=%.ko) + @: + +# modname and part-of-module are set to make c_flags define proper module flags +modname = $(notdir $(@:.mod.o=)) +part-of-module = y +GCOV_PROFILE := n +ccflags-remove-y := $(CC_FLAGS_CFI) + +%.mod.o: %.mod.c FORCE + $(call if_changed_rule,cc_o_c) + +.module-common.o: $(srctree)/scripts/module-common.c FORCE + $(call if_changed_rule,cc_o_c) + +ifneq ($(WARN_ON_UNUSED_TRACEPOINTS),) +cmd_check_tracepoint = $(objtree)/scripts/tracepoint-update --module $<; +endif + +quiet_cmd_ld_ko_o = LD [M] $@ + cmd_ld_ko_o = \ + $(LD) -r $(KBUILD_LDFLAGS) \ + $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \ + -T $(objtree)/scripts/module.lds -o $@ $(filter %.o, $^) + +quiet_cmd_btf_ko = BTF [M] $@ + cmd_btf_ko = \ + if [ ! -f $(objtree)/vmlinux ]; then \ + printf "Skipping BTF generation for %s due to unavailability of vmlinux\n" $@ 1>&2; \ + else \ + $(CONFIG_SHELL) $(srctree)/scripts/gen-btf.sh --btf_base $(objtree)/vmlinux $@; \ + fi; + +# Re-generate module BTFs if either module's .ko or vmlinux changed +%.ko: %.o %.mod.o .module-common.o $(objtree)/scripts/module.lds $(and $(CONFIG_DEBUG_INFO_BTF_MODULES),$(KBUILD_BUILTIN),$(objtree)/vmlinux) FORCE + +$(call if_changed,ld_ko_o) +ifdef CONFIG_DEBUG_INFO_BTF_MODULES + +$(if $(newer-prereqs),$(call cmd,btf_ko)) +endif + +$(call cmd,check_tracepoint) + +targets += $(modules:%.o=%.ko) $(modules:%.o=%.mod.o) .module-common.o + +# Add FORCE to the prerequisites of a target to force it to be always rebuilt. +# --------------------------------------------------------------------------- + +PHONY += FORCE +FORCE: + +# Read all saved command lines and dependencies for the $(targets) we +# may be building above, using $(if_changed{,_dep}). As an +# optimization, we don't need to read them if the target does not +# exist, we will rebuild anyway in that case. + +existing-targets := $(wildcard $(sort $(targets))) + +-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) + +.PHONY: $(PHONY) -- cgit v1.3.1