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.vmlinux_a | 82 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 82 insertions(+) create mode 100644 scripts/Makefile.vmlinux_a (limited to 'scripts/Makefile.vmlinux_a') diff --git a/scripts/Makefile.vmlinux_a b/scripts/Makefile.vmlinux_a new file mode 100644 index 000000000..395e29998 --- /dev/null +++ b/scripts/Makefile.vmlinux_a @@ -0,0 +1,82 @@ +# SPDX-License-Identifier: GPL-2.0-only + +PHONY := __default +__default: vmlinux.a + +include include/config/auto.conf +include $(srctree)/scripts/Kbuild.include +include $(srctree)/scripts/Makefile.lib + +# Link of built-in-fixup.a +# --------------------------------------------------------------------------- + +quiet_cmd_ar_builtin_fixup = AR $@ + cmd_ar_builtin_fixup = \ + rm -f $@; \ + $(AR) cDPrST $@ $(KBUILD_VMLINUX_OBJS); \ + $(AR) mPi $$($(AR) t $@ | sed -n 1p) $@ $$($(AR) t $@ | grep -F -f $(srctree)/scripts/head-object-list.txt) + +targets += built-in-fixup.a +built-in-fixup.a: $(KBUILD_VMLINUX_OBJS) scripts/head-object-list.txt FORCE + $(call if_changed,ar_builtin_fixup) + +ifdef CONFIG_LTO_CLANG_THIN_DIST + +quiet_cmd_builtin.order = GEN $@ + cmd_builtin.order = $(AR) t $< > $@ + +targets += builtin.order +builtin.order: built-in-fixup.a FORCE + $(call if_changed,builtin.order) + +quiet_cmd_ld_thinlto_index = LD $@ + cmd_ld_thinlto_index = \ + $(LD) $(KBUILD_LDFLAGS) -r --thinlto-index-only=$@ @$< + +targets += vmlinux.thinlto-index +vmlinux.thinlto-index: builtin.order FORCE + $(call if_changed,ld_thinlto_index) + +quiet_cmd_ar_vmlinux.a = GEN $@ + cmd_ar_vmlinux.a = \ + rm -f $@; \ + while read -r obj; do \ + if grep -Fqx $${obj} $(word 2, $^); then \ + echo $${obj%.o}.thinlto-native.o; \ + else \ + echo $${obj}; \ + fi; \ + done < $< | xargs $(AR) cDPrS --thin $@ + +targets += vmlinux.a +vmlinux.a: builtin.order vmlinux.thinlto-index FORCE + $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.thinlto + $(call if_changed,ar_vmlinux.a) + +else + +# vmlinux.a +# --------------------------------------------------------------------------- + +targets += vmlinux.a +vmlinux.a: built-in-fixup.a FORCE + $(call if_changed,copy) + +endif + +# 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