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.userprogs | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 scripts/Makefile.userprogs (limited to 'scripts/Makefile.userprogs') diff --git a/scripts/Makefile.userprogs b/scripts/Makefile.userprogs new file mode 100644 index 000000000..f3a7e1ef3 --- /dev/null +++ b/scripts/Makefile.userprogs @@ -0,0 +1,45 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Build userspace programs for the target system +# + +# Executables compiled from a single .c file +user-csingle := $(foreach m, $(userprogs), $(if $($(m)-objs),,$(m))) + +# Executables linked based on several .o files +user-cmulti := $(foreach m, $(userprogs), $(if $($(m)-objs),$(m))) + +# Objects compiled from .c files +user-cobjs := $(sort $(foreach m, $(userprogs), $($(m)-objs))) + +user-csingle := $(addprefix $(obj)/, $(user-csingle)) +user-cmulti := $(addprefix $(obj)/, $(user-cmulti)) +user-cobjs := $(addprefix $(obj)/, $(user-cobjs)) + +user_ccflags = -Wp,-MMD,$(depfile) $(KBUILD_USERCFLAGS) $(userccflags) \ + $($(target-stem)-userccflags) +user_ldflags = $(KBUILD_USERLDFLAGS) $(userldflags) $($(target-stem)-userldflags) +user_ldlibs = $(userldlibs) $($(target-stem)-userldlibs) + +# Create an executable from a single .c file +quiet_cmd_user_cc_c = CC [U] $@ + cmd_user_cc_c = $(CC) $(user_ccflags) $(user_ldflags) -o $@ $< \ + $(user_ldlibs) +$(user-csingle): $(obj)/%: $(src)/%.c FORCE + $(call if_changed_dep,user_cc_c) + +# Link an executable based on list of .o files +quiet_cmd_user_ld = LD [U] $@ + cmd_user_ld = $(CC) $(user_ldflags) -o $@ \ + $(addprefix $(obj)/, $($(target-stem)-objs)) $(user_ldlibs) +$(user-cmulti): FORCE + $(call if_changed,user_ld) +$(call multi_depend, $(user-cmulti), , -objs) + +# Create .o file from a .c file +quiet_cmd_user_cc_o_c = CC [U] $@ + cmd_user_cc_o_c = $(CC) $(user_ccflags) -c -o $@ $< +$(user-cobjs): $(obj)/%.o: $(src)/%.c FORCE + $(call if_changed_dep,user_cc_o_c) + +targets += $(user-csingle) $(user-cmulti) $(user-cobjs) -- cgit v1.3.1