https://github.com/torvalds/linux
Revision a4f4d6df537368297a84e6b9444f403f99bf59f6 authored by J. Bruce Fields on 08 December 2008, 23:24:18 UTC, committed by Linus Torvalds on 09 December 2008, 03:49:32 UTC
While 440037287c5 "[PATCH] switch all filesystems over to
d_obtain_alias" removed some cases where fh_to_dentry() and
fh_to_parent() could return NULL, there are still a few NULL returns
left in individual filesystems.  Thus it was a mistake for that commit
to remove the handling of NULL returns in the callers.

Revert those parts of 440037287c5 which removed the NULL handling.

(We could, alternatively, modify all implementations to return -ESTALE
instead of NULL, but that proves to require fixing a number of
filesystems, and in some cases it's arguably more natural to return
NULL.)

Thanks to David for original patch and Linus, Christoph, and Hugh for
review.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Cc: David Howells <dhowells@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 218d11a
Raw File
Tip revision: a4f4d6df537368297a84e6b9444f403f99bf59f6 authored by J. Bruce Fields on 08 December 2008, 23:24:18 UTC
EXPORTFS: handle NULL returns from fh_to_dentry()/fh_to_parent()
Tip revision: a4f4d6d
vmlinux.lds.h
#ifndef LOAD_OFFSET
#define LOAD_OFFSET 0
#endif

#ifndef VMLINUX_SYMBOL
#define VMLINUX_SYMBOL(_sym_) _sym_
#endif

/* Align . to a 8 byte boundary equals to maximum function alignment. */
#define ALIGN_FUNCTION()  . = ALIGN(8)

/* The actual configuration determine if the init/exit sections
 * are handled as text/data or they can be discarded (which
 * often happens at runtime)
 */
#ifdef CONFIG_HOTPLUG
#define DEV_KEEP(sec)    *(.dev##sec)
#define DEV_DISCARD(sec)
#else
#define DEV_KEEP(sec)
#define DEV_DISCARD(sec) *(.dev##sec)
#endif

#ifdef CONFIG_HOTPLUG_CPU
#define CPU_KEEP(sec)    *(.cpu##sec)
#define CPU_DISCARD(sec)
#else
#define CPU_KEEP(sec)
#define CPU_DISCARD(sec) *(.cpu##sec)
#endif

#if defined(CONFIG_MEMORY_HOTPLUG)
#define MEM_KEEP(sec)    *(.mem##sec)
#define MEM_DISCARD(sec)
#else
#define MEM_KEEP(sec)
#define MEM_DISCARD(sec) *(.mem##sec)
#endif

#ifdef CONFIG_FTRACE_MCOUNT_RECORD
#define MCOUNT_REC()	VMLINUX_SYMBOL(__start_mcount_loc) = .; \
			*(__mcount_loc)				\
			VMLINUX_SYMBOL(__stop_mcount_loc) = .;
#else
#define MCOUNT_REC()
#endif

/* .data section */
#define DATA_DATA							\
	*(.data)							\
	*(.data.init.refok)						\
	*(.ref.data)							\
	DEV_KEEP(init.data)						\
	DEV_KEEP(exit.data)						\
	CPU_KEEP(init.data)						\
	CPU_KEEP(exit.data)						\
	MEM_KEEP(init.data)						\
	MEM_KEEP(exit.data)						\
	. = ALIGN(8);							\
	VMLINUX_SYMBOL(__start___markers) = .;				\
	*(__markers)							\
	VMLINUX_SYMBOL(__stop___markers) = .;				\
	VMLINUX_SYMBOL(__start___tracepoints) = .;			\
	*(__tracepoints)						\
	VMLINUX_SYMBOL(__stop___tracepoints) = .;

#define RO_DATA(align)							\
	. = ALIGN((align));						\
	.rodata           : AT(ADDR(.rodata) - LOAD_OFFSET) {		\
		VMLINUX_SYMBOL(__start_rodata) = .;			\
		*(.rodata) *(.rodata.*)					\
		*(__vermagic)		/* Kernel version magic */	\
		*(__markers_strings)	/* Markers: strings */		\
		*(__tracepoints_strings)/* Tracepoints: strings */	\
	}								\
									\
	.rodata1          : AT(ADDR(.rodata1) - LOAD_OFFSET) {		\
		*(.rodata1)						\
	}								\
									\
	BUG_TABLE							\
									\
	/* PCI quirks */						\
	.pci_fixup        : AT(ADDR(.pci_fixup) - LOAD_OFFSET) {	\
		VMLINUX_SYMBOL(__start_pci_fixups_early) = .;		\
		*(.pci_fixup_early)					\
		VMLINUX_SYMBOL(__end_pci_fixups_early) = .;		\
		VMLINUX_SYMBOL(__start_pci_fixups_header) = .;		\
		*(.pci_fixup_header)					\
		VMLINUX_SYMBOL(__end_pci_fixups_header) = .;		\
		VMLINUX_SYMBOL(__start_pci_fixups_final) = .;		\
		*(.pci_fixup_final)					\
		VMLINUX_SYMBOL(__end_pci_fixups_final) = .;		\
		VMLINUX_SYMBOL(__start_pci_fixups_enable) = .;		\
		*(.pci_fixup_enable)					\
		VMLINUX_SYMBOL(__end_pci_fixups_enable) = .;		\
		VMLINUX_SYMBOL(__start_pci_fixups_resume) = .;		\
		*(.pci_fixup_resume)					\
		VMLINUX_SYMBOL(__end_pci_fixups_resume) = .;		\
		VMLINUX_SYMBOL(__start_pci_fixups_resume_early) = .;	\
		*(.pci_fixup_resume_early)				\
		VMLINUX_SYMBOL(__end_pci_fixups_resume_early) = .;	\
		VMLINUX_SYMBOL(__start_pci_fixups_suspend) = .;		\
		*(.pci_fixup_suspend)					\
		VMLINUX_SYMBOL(__end_pci_fixups_suspend) = .;		\
	}								\
									\
	/* Built-in firmware blobs */					\
	.builtin_fw        : AT(ADDR(.builtin_fw) - LOAD_OFFSET) {	\
		VMLINUX_SYMBOL(__start_builtin_fw) = .;			\
		*(.builtin_fw)						\
		VMLINUX_SYMBOL(__end_builtin_fw) = .;			\
	}								\
									\
	/* RapidIO route ops */						\
	.rio_route        : AT(ADDR(.rio_route) - LOAD_OFFSET) {	\
		VMLINUX_SYMBOL(__start_rio_route_ops) = .;		\
		*(.rio_route_ops)					\
		VMLINUX_SYMBOL(__end_rio_route_ops) = .;		\
	}								\
									\
	TRACEDATA							\
									\
	/* Kernel symbol table: Normal symbols */			\
	__ksymtab         : AT(ADDR(__ksymtab) - LOAD_OFFSET) {		\
		VMLINUX_SYMBOL(__start___ksymtab) = .;			\
		*(__ksymtab)						\
		VMLINUX_SYMBOL(__stop___ksymtab) = .;			\
	}								\
									\
	/* Kernel symbol table: GPL-only symbols */			\
	__ksymtab_gpl     : AT(ADDR(__ksymtab_gpl) - LOAD_OFFSET) {	\
		VMLINUX_SYMBOL(__start___ksymtab_gpl) = .;		\
		*(__ksymtab_gpl)					\
		VMLINUX_SYMBOL(__stop___ksymtab_gpl) = .;		\
	}								\
									\
	/* Kernel symbol table: Normal unused symbols */		\
	__ksymtab_unused  : AT(ADDR(__ksymtab_unused) - LOAD_OFFSET) {	\
		VMLINUX_SYMBOL(__start___ksymtab_unused) = .;		\
		*(__ksymtab_unused)					\
		VMLINUX_SYMBOL(__stop___ksymtab_unused) = .;		\
	}								\
									\
	/* Kernel symbol table: GPL-only unused symbols */		\
	__ksymtab_unused_gpl : AT(ADDR(__ksymtab_unused_gpl) - LOAD_OFFSET) { \
		VMLINUX_SYMBOL(__start___ksymtab_unused_gpl) = .;	\
		*(__ksymtab_unused_gpl)					\
		VMLINUX_SYMBOL(__stop___ksymtab_unused_gpl) = .;	\
	}								\
									\
	/* Kernel symbol table: GPL-future-only symbols */		\
	__ksymtab_gpl_future : AT(ADDR(__ksymtab_gpl_future) - LOAD_OFFSET) { \
		VMLINUX_SYMBOL(__start___ksymtab_gpl_future) = .;	\
		*(__ksymtab_gpl_future)					\
		VMLINUX_SYMBOL(__stop___ksymtab_gpl_future) = .;	\
	}								\
									\
	/* Kernel symbol table: Normal symbols */			\
	__kcrctab         : AT(ADDR(__kcrctab) - LOAD_OFFSET) {		\
		VMLINUX_SYMBOL(__start___kcrctab) = .;			\
		*(__kcrctab)						\
		VMLINUX_SYMBOL(__stop___kcrctab) = .;			\
	}								\
									\
	/* Kernel symbol table: GPL-only symbols */			\
	__kcrctab_gpl     : AT(ADDR(__kcrctab_gpl) - LOAD_OFFSET) {	\
		VMLINUX_SYMBOL(__start___kcrctab_gpl) = .;		\
		*(__kcrctab_gpl)					\
		VMLINUX_SYMBOL(__stop___kcrctab_gpl) = .;		\
	}								\
									\
	/* Kernel symbol table: Normal unused symbols */		\
	__kcrctab_unused  : AT(ADDR(__kcrctab_unused) - LOAD_OFFSET) {	\
		VMLINUX_SYMBOL(__start___kcrctab_unused) = .;		\
		*(__kcrctab_unused)					\
		VMLINUX_SYMBOL(__stop___kcrctab_unused) = .;		\
	}								\
									\
	/* Kernel symbol table: GPL-only unused symbols */		\
	__kcrctab_unused_gpl : AT(ADDR(__kcrctab_unused_gpl) - LOAD_OFFSET) { \
		VMLINUX_SYMBOL(__start___kcrctab_unused_gpl) = .;	\
		*(__kcrctab_unused_gpl)					\
		VMLINUX_SYMBOL(__stop___kcrctab_unused_gpl) = .;	\
	}								\
									\
	/* Kernel symbol table: GPL-future-only symbols */		\
	__kcrctab_gpl_future : AT(ADDR(__kcrctab_gpl_future) - LOAD_OFFSET) { \
		VMLINUX_SYMBOL(__start___kcrctab_gpl_future) = .;	\
		*(__kcrctab_gpl_future)					\
		VMLINUX_SYMBOL(__stop___kcrctab_gpl_future) = .;	\
	}								\
									\
	/* Kernel symbol table: strings */				\
        __ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) {	\
		*(__ksymtab_strings)					\
	}								\
									\
	/* __*init sections */						\
	__init_rodata : AT(ADDR(__init_rodata) - LOAD_OFFSET) {		\
		*(.ref.rodata)						\
		MCOUNT_REC()						\
		DEV_KEEP(init.rodata)					\
		DEV_KEEP(exit.rodata)					\
		CPU_KEEP(init.rodata)					\
		CPU_KEEP(exit.rodata)					\
		MEM_KEEP(init.rodata)					\
		MEM_KEEP(exit.rodata)					\
	}								\
									\
	/* Built-in module parameters. */				\
	__param : AT(ADDR(__param) - LOAD_OFFSET) {			\
		VMLINUX_SYMBOL(__start___param) = .;			\
		*(__param)						\
		VMLINUX_SYMBOL(__stop___param) = .;			\
		. = ALIGN((align));					\
		VMLINUX_SYMBOL(__end_rodata) = .;			\
	}								\
	. = ALIGN((align));

/* RODATA provided for backward compatibility.
 * All archs are supposed to use RO_DATA() */
#define RODATA RO_DATA(4096)

#define SECURITY_INIT							\
	.security_initcall.init : AT(ADDR(.security_initcall.init) - LOAD_OFFSET) { \
		VMLINUX_SYMBOL(__security_initcall_start) = .;		\
		*(.security_initcall.init) 				\
		VMLINUX_SYMBOL(__security_initcall_end) = .;		\
	}

/* .text section. Map to function alignment to avoid address changes
 * during second ld run in second ld pass when generating System.map */
#define TEXT_TEXT							\
		ALIGN_FUNCTION();					\
		*(.text.hot)						\
		*(.text)						\
		*(.ref.text)						\
		*(.text.init.refok)					\
		*(.exit.text.refok)					\
	DEV_KEEP(init.text)						\
	DEV_KEEP(exit.text)						\
	CPU_KEEP(init.text)						\
	CPU_KEEP(exit.text)						\
	MEM_KEEP(init.text)						\
	MEM_KEEP(exit.text)						\
		*(.text.unlikely)


/* sched.text is aling to function alignment to secure we have same
 * address even at second ld pass when generating System.map */
#define SCHED_TEXT							\
		ALIGN_FUNCTION();					\
		VMLINUX_SYMBOL(__sched_text_start) = .;			\
		*(.sched.text)						\
		VMLINUX_SYMBOL(__sched_text_end) = .;

/* spinlock.text is aling to function alignment to secure we have same
 * address even at second ld pass when generating System.map */
#define LOCK_TEXT							\
		ALIGN_FUNCTION();					\
		VMLINUX_SYMBOL(__lock_text_start) = .;			\
		*(.spinlock.text)					\
		VMLINUX_SYMBOL(__lock_text_end) = .;

#define KPROBES_TEXT							\
		ALIGN_FUNCTION();					\
		VMLINUX_SYMBOL(__kprobes_text_start) = .;		\
		*(.kprobes.text)					\
		VMLINUX_SYMBOL(__kprobes_text_end) = .;

/* Section used for early init (in .S files) */
#define HEAD_TEXT  *(.head.text)

/* init and exit section handling */
#define INIT_DATA							\
	*(.init.data)							\
	DEV_DISCARD(init.data)						\
	DEV_DISCARD(init.rodata)					\
	CPU_DISCARD(init.data)						\
	CPU_DISCARD(init.rodata)					\
	MEM_DISCARD(init.data)						\
	MEM_DISCARD(init.rodata)					\
	/* implement dynamic printk debug */				\
	VMLINUX_SYMBOL(__start___verbose_strings) = .;                  \
	*(__verbose_strings)                                            \
	VMLINUX_SYMBOL(__stop___verbose_strings) = .;                   \
	. = ALIGN(8);							\
	VMLINUX_SYMBOL(__start___verbose) = .;                          \
	*(__verbose)                                                    \
	VMLINUX_SYMBOL(__stop___verbose) = .;

#define INIT_TEXT							\
	*(.init.text)							\
	DEV_DISCARD(init.text)						\
	CPU_DISCARD(init.text)						\
	MEM_DISCARD(init.text)

#define EXIT_DATA							\
	*(.exit.data)							\
	DEV_DISCARD(exit.data)						\
	DEV_DISCARD(exit.rodata)					\
	CPU_DISCARD(exit.data)						\
	CPU_DISCARD(exit.rodata)					\
	MEM_DISCARD(exit.data)						\
	MEM_DISCARD(exit.rodata)

#define EXIT_TEXT							\
	*(.exit.text)							\
	DEV_DISCARD(exit.text)						\
	CPU_DISCARD(exit.text)						\
	MEM_DISCARD(exit.text)

		/* DWARF debug sections.
		Symbols in the DWARF debugging sections are relative to
		the beginning of the section so we begin them at 0.  */
#define DWARF_DEBUG							\
		/* DWARF 1 */						\
		.debug          0 : { *(.debug) }			\
		.line           0 : { *(.line) }			\
		/* GNU DWARF 1 extensions */				\
		.debug_srcinfo  0 : { *(.debug_srcinfo) }		\
		.debug_sfnames  0 : { *(.debug_sfnames) }		\
		/* DWARF 1.1 and DWARF 2 */				\
		.debug_aranges  0 : { *(.debug_aranges) }		\
		.debug_pubnames 0 : { *(.debug_pubnames) }		\
		/* DWARF 2 */						\
		.debug_info     0 : { *(.debug_info			\
				.gnu.linkonce.wi.*) }			\
		.debug_abbrev   0 : { *(.debug_abbrev) }		\
		.debug_line     0 : { *(.debug_line) }			\
		.debug_frame    0 : { *(.debug_frame) }			\
		.debug_str      0 : { *(.debug_str) }			\
		.debug_loc      0 : { *(.debug_loc) }			\
		.debug_macinfo  0 : { *(.debug_macinfo) }		\
		/* SGI/MIPS DWARF 2 extensions */			\
		.debug_weaknames 0 : { *(.debug_weaknames) }		\
		.debug_funcnames 0 : { *(.debug_funcnames) }		\
		.debug_typenames 0 : { *(.debug_typenames) }		\
		.debug_varnames  0 : { *(.debug_varnames) }		\

		/* Stabs debugging sections.  */
#define STABS_DEBUG							\
		.stab 0 : { *(.stab) }					\
		.stabstr 0 : { *(.stabstr) }				\
		.stab.excl 0 : { *(.stab.excl) }			\
		.stab.exclstr 0 : { *(.stab.exclstr) }			\
		.stab.index 0 : { *(.stab.index) }			\
		.stab.indexstr 0 : { *(.stab.indexstr) }		\
		.comment 0 : { *(.comment) }

#ifdef CONFIG_GENERIC_BUG
#define BUG_TABLE							\
	. = ALIGN(8);							\
	__bug_table : AT(ADDR(__bug_table) - LOAD_OFFSET) {		\
		VMLINUX_SYMBOL(__start___bug_table) = .;		\
		*(__bug_table)						\
		VMLINUX_SYMBOL(__stop___bug_table) = .;			\
	}
#else
#define BUG_TABLE
#endif

#ifdef CONFIG_PM_TRACE
#define TRACEDATA							\
	. = ALIGN(4);							\
	.tracedata : AT(ADDR(.tracedata) - LOAD_OFFSET) {		\
		VMLINUX_SYMBOL(__tracedata_start) = .;			\
		*(.tracedata)						\
		VMLINUX_SYMBOL(__tracedata_end) = .;			\
	}
#else
#define TRACEDATA
#endif

#define NOTES								\
	.notes : AT(ADDR(.notes) - LOAD_OFFSET) {			\
		VMLINUX_SYMBOL(__start_notes) = .;			\
		*(.note.*)						\
		VMLINUX_SYMBOL(__stop_notes) = .;			\
	}

#define INITCALLS							\
	*(.initcallearly.init)						\
	VMLINUX_SYMBOL(__early_initcall_end) = .;			\
  	*(.initcall0.init)						\
  	*(.initcall0s.init)						\
  	*(.initcall1.init)						\
  	*(.initcall1s.init)						\
  	*(.initcall2.init)						\
  	*(.initcall2s.init)						\
  	*(.initcall3.init)						\
  	*(.initcall3s.init)						\
  	*(.initcall4.init)						\
  	*(.initcall4s.init)						\
  	*(.initcall5.init)						\
  	*(.initcall5s.init)						\
	*(.initcallrootfs.init)						\
  	*(.initcall6.init)						\
  	*(.initcall6s.init)						\
  	*(.initcall7.init)						\
  	*(.initcall7s.init)

#define PERCPU(align)							\
	. = ALIGN(align);						\
	VMLINUX_SYMBOL(__per_cpu_start) = .;				\
	.data.percpu  : AT(ADDR(.data.percpu) - LOAD_OFFSET) {		\
		*(.data.percpu.page_aligned)				\
		*(.data.percpu)						\
		*(.data.percpu.shared_aligned)				\
	}								\
	VMLINUX_SYMBOL(__per_cpu_end) = .;
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