Kirill Korotaev [Wed, 17 Oct 2007 16:04:33 +0000 (18:04 +0200)]
x86: mark read_crX() asm code as volatile
Some gcc versions (I checked at least 4.1.1 from RHEL5 & 4.1.2 from gentoo)
can generate incorrect code with read_crX()/write_crX() functions mix up,
due to cached results of read_crX().
The small app for x8664 below compiled with -O2 demonstrates this
(i686 does the same thing):
Andrey Mirkin [Wed, 17 Oct 2007 16:04:33 +0000 (18:04 +0200)]
x86: return correct error code from child_rip in x86_64 entry.S
Right now register edi is just cleared before calling do_exit.
That is wrong because correct return value will be ignored.
Value from rax should be copied to rdi instead of clearing edi.
AK: changed to 32bit move because it's strictly an int
Jan Beulich [Wed, 17 Oct 2007 16:04:33 +0000 (18:04 +0200)]
i386: avoid temporarily inconsistent pte-s
One more of these issues (which were considered fixed a few releases
back): other than on x86-64, i386 allows set_fixmap() to replace
already present mappings. Consequently, on PAE, care must be taken to
not update the high half of a pte while the low half is still holding
the old value.
Satyam Sharma [Wed, 17 Oct 2007 16:04:33 +0000 (18:04 +0200)]
i386: Fix section mismatch
Fix bugzilla #8679
WARNING: arch/i386/kernel/built-in.o(.data+0x2148): Section mismatch: reference
to .init.text: (between 'thermal_throttle_cpu_notifier' and 'mtrr_mutex')
comes because struct notifier_block thermal_throttle_cpu_notifier in
arch/i386/kernel/cpu/mcheck/therm_throt.c goes in .data section but the
notifier callback function itself has been marked __cpuinit which becomes
__init == .init.text when HOTPLUG_CPU=n. The warning is bogus because the
callback will never be called out if HOTPLUG_CPU=n in the first place (as
one can see from kernel/cpu.c, the cpu_chain itself is __cpuinitdata :-)
So, let's mark thermal_throttle_cpu_notifier as __cpuinitdata to fix
the section mismatch warning.
[ tglx: arch/x86 adaptation ]
Signed-off-by: Satyam Sharma <satyam@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Siddha, Suresh B [Wed, 17 Oct 2007 16:04:33 +0000 (18:04 +0200)]
i386: fix 4 bit apicid assumption of mach-default
Fix get_apic_id() in mach-default, so that it uses 8 bits incase of
xAPIC case and 4 bits for legacy APIC case.
This fixes the i386 kernel assumption that apic id is less than 16 for
xAPIC platforms with 8 cpus or less and makes the kernel boot on such
platforms.
[ tglx: arch/x86 adaptation ]
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Andrew Hastings [Wed, 17 Oct 2007 16:04:33 +0000 (18:04 +0200)]
x86: fix off-by-one in find_next_zero_string
Fix an off-by-one error in find_next_zero_string which prevents
allocating the last bit.
[ tglx: arch/x86 adaptation ]
Signed-off-by: Andrew Hastings <abh@cray.com> on behalf of Cray Inc. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Roland McGrath [Wed, 17 Oct 2007 16:04:32 +0000 (18:04 +0200)]
x86: Install unstripped copy of 64bit vdso to disk
This keeps an unstripped copy of the 64bit vDSO images built before they are
stripped and embedded in the kernel. The unstripped copies get installed
in $(MODLIB)/vdso/ by "make install" (or you can explicitly use the
subtarget "make vdso_install"). These files can be useful when they
contain source-level debugging information.
[ tglx: arch/x86 adaptation ]
Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Roland McGrath [Wed, 17 Oct 2007 16:04:32 +0000 (18:04 +0200)]
x86_64: install unstripped copies of compat vdso on disk
This keeps an unstripped copy of the vDSO images built before they are
stripped and embedded in the kernel. The unstripped copies get installed
in $(MODLIB)/vdso/ by "make install" (or you can explicitly use the
subtarget "make vdso_install"). These files can be useful when they
contain source-level debugging information.
[ tglx: arch/x86 adaptation ]
Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Thomas Gleixner [Wed, 17 Oct 2007 16:04:32 +0000 (18:04 +0200)]
x86: C1E late detection fix. Really switch off lapic timer
Doh, I completely missed that devices marked DUMMY are not running
the set_mode function. So we force broadcasting, but we keep the
local APIC timer running.
Let the clock event layer mark the device _after_ switching it off.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Linus Torvalds [Wed, 17 Oct 2007 16:05:55 +0000 (09:05 -0700)]
Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc: (24 commits)
[POWERPC] Fix vmemmap warning in init_64.c
[POWERPC] Fix 64 bits vDSO DWARF info for CR register
[POWERPC] Add 1TB workaround for PA6T
[POWERPC] Enable NO_HZ and high res timers for pseries and ppc64 configs
[POWERPC] Quieten cache information at boot
[POWERPC] Quieten clockevent printk
[POWERPC] Enable SLUB in *_defconfig
[POWERPC] Fix 1TB segment detection
[POWERPC] Fix iSeries_hpte_insert prototype
[POWERPC] Fix copyright symbol
[POWERPC] ibmebus: Move to of_device and of_platform_driver, match eHCA and eHEA drivers
[POWERPC] ibmebus: Add device creation and bus probing based on of_device
[POWERPC] ibmebus: Remove bus match/probe/remove functions
[POWERPC] Move of_device allocation into of_device.[ch]
[POWERPC] mpc52xx: device tree changes for FEC and MDIO
[POWERPC] bestcomm: GenBD task support
[POWERPC] bestcomm: FEC task support
[POWERPC] bestcomm: ATA task support
[POWERPC] bestcomm: core bestcomm support for Freescale MPC5200
[POWERPC] mpc52xx: Update mpc52xx_psc structure with B revision changes
...
Linus Torvalds [Wed, 17 Oct 2007 16:04:11 +0000 (09:04 -0700)]
Merge branch 'for-linus' of git://oss.sgi.com:8090/xfs/xfs-2.6
* 'for-linus' of git://oss.sgi.com:8090/xfs/xfs-2.6: (59 commits)
[XFS] eagerly remove vmap mappings to avoid upsetting Xen
[XFS] simplify validata_fields
[XFS] no longer using io_vnode, as was remaining from 23 cherrypick
[XFS] Remove STATIC which was missing from prior manual merge
[XFS] Put back the QUEUE_ORDERED_NONE test in the barrier check.
[XFS] Turn off XBF_ASYNC flag before re-reading superblock.
[XFS] avoid race in sync_inodes() that can fail to write out all dirty data
[XFS] This fix prevents bulkstat from spinning in an infinite loop.
[XFS] simplify xfs_create/mknod/symlink prototype
[XFS] avoid xfs_getattr in XFS_IOC_FSGETXATTR ioctl
[XFS] get_bulkall() could return incorrect inode state
[XFS] Kill unused IOMAP_EOF flag
[XFS] fix when DMAPI mount option processing happens
[XFS] ensure file size is logged on synchronous writes
[XFS] growlock should be a mutex
[XFS] replace some large xfs_log_priv.h macros by proper functions
[XFS] kill struct bhv_vfs
[XFS] move syncing related members from struct bhv_vfs to struct xfs_mount
[XFS] kill the vfs_flags member in struct bhv_vfs
[XFS] kill the vfs_fsid and vfs_altfsid members in struct bhv_vfs
...
Linus Torvalds [Wed, 17 Oct 2007 16:00:30 +0000 (09:00 -0700)]
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/hpa/linux-2.6-x86setup
* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/hpa/linux-2.6-x86setup:
Remove magic macros for screen_info structure members
[x86] remove uses of magic macros for boot_params access
Adrian Bunk [Wed, 17 Oct 2007 06:31:38 +0000 (23:31 -0700)]
security/ cleanups
This patch contains the following cleanups that are now possible:
- remove the unused security_operations->inode_xattr_getsuffix
- remove the no longer used security_operations->unregister_security
- remove some no longer required exit code
- remove a bunch of no longer used exports
Signed-off-by: Adrian Bunk <bunk@kernel.org> Acked-by: James Morris <jmorris@namei.org> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Serge E. Hallyn [Wed, 17 Oct 2007 06:31:36 +0000 (23:31 -0700)]
Implement file posix capabilities
Implement file posix capabilities. This allows programs to be given a
subset of root's powers regardless of who runs them, without having to use
setuid and giving the binary all of root's powers.
This version works with Kaigai Kohei's userspace tools, found at
http://www.kaigai.gr.jp/index.php. For more information on how to use this
patch, Chris Friedhoff has posted a nice page at
http://www.friedhoff.org/fscaps.html.
Changelog:
Nov 27:
Incorporate fixes from Andrew Morton
(security-introduce-file-caps-tweaks and
security-introduce-file-caps-warning-fix)
Fix Kconfig dependency.
Fix change signaling behavior when file caps are not compiled in.
Nov 13:
Integrate comments from Alexey: Remove CONFIG_ ifdef from
capability.h, and use %zd for printing a size_t.
Nov 13:
Fix endianness warnings by sparse as suggested by Alexey
Dobriyan.
Nov 09:
Address warnings of unused variables at cap_bprm_set_security
when file capabilities are disabled, and simultaneously clean
up the code a little, by pulling the new code into a helper
function.
Nov 08:
For pointers to required userspace tools and how to use
them, see http://www.friedhoff.org/fscaps.html.
Nov 07:
Fix the calculation of the highest bit checked in
check_cap_sanity().
Nov 07:
Allow file caps to be enabled without CONFIG_SECURITY, since
capabilities are the default.
Hook cap_task_setscheduler when !CONFIG_SECURITY.
Move capable(TASK_KILL) to end of cap_task_kill to reduce
audit messages.
Nov 05:
Add secondary calls in selinux/hooks.c to task_setioprio and
task_setscheduler so that selinux and capabilities with file
cap support can be stacked.
Sep 05:
As Seth Arnold points out, uid checks are out of place
for capability code.
Sep 01:
Define task_setscheduler, task_setioprio, cap_task_kill, and
task_setnice to make sure a user cannot affect a process in which
they called a program with some fscaps.
One remaining question is the note under task_setscheduler: are we
ok with CAP_SYS_NICE being sufficient to confine a process to a
cpuset?
It is a semantic change, as without fsccaps, attach_task doesn't
allow CAP_SYS_NICE to override the uid equivalence check. But since
it uses security_task_setscheduler, which elsewhere is used where
CAP_SYS_NICE can be used to override the uid equivalence check,
fixing it might be tough.
task_setscheduler
note: this also controls cpuset:attach_task. Are we ok with
CAP_SYS_NICE being used to confine to a cpuset?
task_setioprio
task_setnice
sys_setpriority uses this (through set_one_prio) for another
process. Need same checks as setrlimit
Aug 21:
Updated secureexec implementation to reflect the fact that
euid and uid might be the same and nonzero, but the process
might still have elevated caps.
Aug 15:
Handle endianness of xattrs.
Enforce capability version match between kernel and disk.
Enforce that no bits beyond the known max capability are
set, else return -EPERM.
With this extra processing, it may be worth reconsidering
doing all the work at bprm_set_security rather than
d_instantiate.
Aug 10:
Always call getxattr at bprm_set_security, rather than
caching it at d_instantiate.
[morgan@kernel.org: file-caps clean up for linux/capability.h]
[bunk@kernel.org: unexport cap_inode_killpriv] Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: James Morris <jmorris@namei.org> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Andrew Morgan <morgan@kernel.org> Signed-off-by: Andrew Morgan <morgan@kernel.org> Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
James Morris [Wed, 17 Oct 2007 06:31:32 +0000 (23:31 -0700)]
security: Convert LSM into a static interface
Convert LSM into a static interface, as the ability to unload a security
module is not required by in-tree users and potentially complicates the
overall security architecture.
Needlessly exported LSM symbols have been unexported, to help reduce API
abuse.
Parameters for the capability and root_plug modules are now specified
at boot.
The SECURITY_FRAMEWORK_VERSION macro has also been removed.
In a nutshell, there is no safe way to unload an LSM. The modular interface
is thus unecessary and broken infrastructure. It is used only by out-of-tree
modules, which are often binary-only, illegal, abusive of the API and
dangerous, e.g. silently re-vectoring SELinux.
[akpm@linux-foundation.org: cleanups]
[akpm@linux-foundation.org: USB Kconfig fix]
[randy.dunlap@oracle.com: fix LSM kernel-doc] Signed-off-by: James Morris <jmorris@namei.org> Acked-by: Chris Wright <chrisw@sous-sol.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: "Serge E. Hallyn" <serue@us.ibm.com> Acked-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rob Landley [Wed, 17 Oct 2007 06:31:31 +0000 (23:31 -0700)]
Fix "make htmldocs" build break.
Fix two htmldocs build breaks, introduced by moving include/linux/usb_gadget.h to
include/linux/usb/gadget.h and combining resume.c and suspend.c into main.c in
drivers/base/power.
Signed-off-by: Rob Landley <rob@landley.net> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rob Landley [Wed, 17 Oct 2007 06:31:30 +0000 (23:31 -0700)]
Add Documentation/RCU/00-Index
Add Documentation/RCU/00-INDEX
Signed-off-by: Rob Landley <rob@landley.net> Acked-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
WANG Cong [Wed, 17 Oct 2007 06:31:29 +0000 (23:31 -0700)]
Documentation/vm/slabinfo.c: clean up this code
This patch does the following cleanups for Documentation/vm/slabinfo.c:
- Fix two memory leaks;
- Constify some char pointers;
- Use snprintf instead of sprintf in case of buffer overflow;
- Fix some indentations;
- Other little improvements.
Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Matthew Wilcox [Wed, 17 Oct 2007 06:31:27 +0000 (23:31 -0700)]
Update DMA-mapping documentation
A couple of updates haven't considered whether the documentation makes
sense as a whole any more. Three changes here:
- Remove the reference to the "DAC Addressing for Address Space Hungry
Devices" section which was deleted by Jan Beulich.
- Remove the comment about DMA_24BIT_MASK which became obsolete when
Tobias Klauser changed the code to actually use DMA_24BIT_MASK.
- Remove the section "64-bit DMA and DAC cycle support" since it's
fully covered above, and contains a reference to the section deleted
by Jan.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bernhard Walle [Wed, 17 Oct 2007 06:31:23 +0000 (23:31 -0700)]
Add reset_devices to the recommended parameters
This patch adds the "reset_devices" option (that's used only by one device
driver for now) to the recommended list of command line parameters for kdump.
Meaning (Documentation/kernel-parameters.txt):
reset_devices [KNL] Force drivers to reset the underlying device
during initialization.
Signed-off-by: Bernhard Walle <bwalle@suse.de> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Cc: Vivek Goyal <vgoyal@in.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Haren Myneni <hbabu@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bernhard Walle [Wed, 17 Oct 2007 06:31:22 +0000 (23:31 -0700)]
Express new ELF32 mechanisms in documentation
This patch reflects the
http://git.kernel.org/?p=linux/kernel/git/horms/kexec-tools-testing.git;a=commit;h=b9c3648e690ad0dad12389659673206213a09760
change in kexec-tools-testing also now in the kernel documentation.
Signed-off-by: Bernhard Walle <bwalle@suse.de> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Cc: Vivek Goyal <vgoyal@in.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Haren Myneni <hbabu@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bernhard Walle [Wed, 17 Oct 2007 06:31:21 +0000 (23:31 -0700)]
Express relocatability of kernel on x86_64 in documentation
This patch adapts the Documentation/kdump/kdump.txt file to express the fact
that the x86_64 kernel is now also relocatable. This makes i386 and x86_64
now behave the same, simplifying the documentation.
Signed-off-by: Bernhard Walle <bwalle@suse.de> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Cc: Vivek Goyal <vgoyal@in.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Haren Myneni <hbabu@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Randy Dunlap [Wed, 17 Oct 2007 06:31:20 +0000 (23:31 -0700)]
kernel-doc: fix doc blocks and html
Johannes Berg reports (Thanks!) that &struct names are not highlighted in
html output format when they are inside a DOC: block.
DOC: blocks were not escaped thru xml_escape() like other kernel-doc
comments were. Fixed that.
However, that left a problem with <p> ($blankline_html) being processed
thru xml_escape(), converting it to <p>, which isn't good for the
generated html output (the <p> should remain unchanged), so this patch also
introduces the notion of "local" kernel-doc meta-characters
('\\\\mnemonic:'), which are converted to html just before writing the
stream to its output file.
Please report any problems that you (anyone) see in "highlighting" in any
output mode (text, man, html, xml).
Also update copyright to include me.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rob Landley [Wed, 17 Oct 2007 06:31:16 +0000 (23:31 -0700)]
Documentation/make/headers_install.txt
Some documentation for "make headers_install".
Signed-off-by: Rob Landley <rob@landley.net> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I'm going to be modifying nfsd_rename() shortly to support read-only bind
mounts. This #ifdef is around the area I'm patching, and it starts to get
really ugly if I just try to add my new code by itself. Using this little
helper makes things a lot cleaner to use.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Acked-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dave Hansen [Wed, 17 Oct 2007 06:31:14 +0000 (23:31 -0700)]
r/o bind mounts: give permission() a local 'mnt' variable
First of all, this makes the structure jumping look a little bit cleaner. So,
this stands alone as a tiny cleanup. But, we also need 'mnt' by itself a few
more times later in this series, so this isn't _just_ a cleanup.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dave Hansen [Wed, 17 Oct 2007 06:31:14 +0000 (23:31 -0700)]
r/o bind mounts: rearrange may_open() to be r/o friendly
may_open() calls vfs_permission() before it does checks for IS_RDONLY(inode).
It checks _again_ inside of vfs_permission().
The check inside of vfs_permission() is going away eventually. With the
mnt_want/drop_write() functions, all of the r/o checks (except for this one)
are consistently done before calling permission(). Because of this, I'd like
to use permission() to hold a debugging check to make sure that the
mnt_want/drop_write() calls are actually being made.
So, to do this:
1. remove the IS_RDONLY() check from permission()
2. enforce that you must mnt_want_write() before
even calling permission()
3. actually add the debugging check to permission()
We need to rearrange may_open() to do r/o checks before calling permission().
Here's the patch.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dave Hansen [Wed, 17 Oct 2007 06:31:13 +0000 (23:31 -0700)]
r/o bind mounts: filesystem helpers for custom 'struct file's
Why do we need r/o bind mounts?
This feature allows a read-only view into a read-write filesystem. In the
process of doing that, it also provides infrastructure for keeping track of
the number of writers to any given mount.
This has a number of uses. It allows chroots to have parts of filesystems
writable. It will be useful for containers in the future because users may
have root inside a container, but should not be allowed to write to
somefilesystems. This also replaces patches that vserver has had out of the
tree for several years.
It allows security enhancement by making sure that parts of your filesystem
read-only (such as when you don't trust your FTP server), when you don't want
to have entire new filesystems mounted, or when you want atime selectively
updated. I've been using the following script to test that the feature is
working as desired. It takes a directory and makes a regular bind and a r/o
bind mount of it. It then performs some normal filesystem operations on the
three directories, including ones that are expected to fail, like creating a
file on the r/o mount.
This patch:
Some filesystems forego the vfs and may_open() and create their own 'struct
file's.
This patch creates a couple of helper functions which can be used by these
filesystems, and will provide a unified place which the r/o bind mount code
may patch.
Also, rename an existing, static-scope init_file() to a less generic name.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bjorn Helgaas [Wed, 17 Oct 2007 06:31:12 +0000 (23:31 -0700)]
PNP: add debug message for adding new device
Add PNP debug message when adding a device, remove similar PNPACPI message
with less information.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com> Cc: Adam Belay <ambx1@neo.rr.com> Cc: Len Brown <lenb@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bjorn Helgaas [Wed, 17 Oct 2007 06:31:11 +0000 (23:31 -0700)]
PNP: simplify PNPBIOS insert_device
Hoist the struct pnp_dev alloc up into the function where it's used.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com> Cc: Adam Belay <ambx1@neo.rr.com> Cc: Len Brown <lenb@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bjorn Helgaas [Wed, 17 Oct 2007 06:31:11 +0000 (23:31 -0700)]
PNP: use dev_info() in system driver
Use dev_info() for a little consistency. Changes this:
pnp: 00:01: ioport range 0xf50-0xf58 has been reserved
pnp: 00:01: ioport range 0x408-0x40f has been reserved
pnp: 00:01: ioport range 0x900-0x903 has been reserved
to this:
system 00:01: ioport range 0xf50-0xf58 has been reserved
system 00:01: ioport range 0x408-0x40f has been reserved
system 00:01: ioport range 0x900-0x903 has been reserved
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com> Cc: Adam Belay <ambx1@neo.rr.com> Cc: Len Brown <lenb@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bjorn Helgaas [Wed, 17 Oct 2007 06:31:09 +0000 (23:31 -0700)]
PNP: simplify PNP card error handling
No functional change; just return errors early instead of putting the main
part of the function inside an "if" statement.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com> Cc: Adam Belay <ambx1@neo.rr.com> Cc: Len Brown <lenb@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bjorn Helgaas [Wed, 17 Oct 2007 06:31:09 +0000 (23:31 -0700)]
PNP: remove null pointer checks
Remove some null pointer checks. Null pointers in these areas indicate
programming errors, and I think it's better to oops immediately rather than
return an error that is easily ignored.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com> Cc: Adam Belay <ambx1@neo.rr.com> Cc: Len Brown <lenb@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Jan Beulich [Wed, 17 Oct 2007 06:31:07 +0000 (23:31 -0700)]
PNP: don't fail device init if no DMA channel available
Most drivers for devices supporting ISA DMA can operate without DMA as well
(falling back zo PIO). Thus it seems inappropriate for PNP to fail device
initialization in case none of the possible DMA channels are available.
Instead, it should be left to the driver to decide what to do if
request_dma() fails.
The patch at once adjusts the code to account for the fact that
pnp_assign_dma() now doesn't need to report failure anymore.
Signed-off-by: Jan Beulich <jbeulich@novell.com> Cc: Adam Belay <ambx1@neo.rr.com> Cc: Bjorn Helgaas <bjorn.helgaas@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
pnpacpi_suspend() doesn't check the result returned by
acpi_pm_device_sleep_state() before passing it to acpi_bus_set_power(),
which may not be desirable. Make it select the target power state of the
device using its second argument if acpi_pm_device_sleep_state() fails.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Looks-ok-to: Pavel Machek <pavel@ucw.cz> Cc: Adam Belay <ambx1@neo.rr.com> Cc: Bjorn Helgaas <bjorn.helgaas@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Miklos Szeredi [Wed, 17 Oct 2007 06:31:05 +0000 (23:31 -0700)]
fuse: no ENOENT from fuse device read
Don't return -ENOENT for a read() on the fuse device when the request was
aborted. Instead return -ENODEV, meaning the filesystem has been
force-umounted or aborted.
Previously ENOENT meant that the request was interrupted, but now the
'aborted' flag is not set in case of interrupts.
Miklos Szeredi [Wed, 17 Oct 2007 06:31:04 +0000 (23:31 -0700)]
fuse: no abort on interrupt
Don't set 'aborted' flag on a request if it's interrupted. We have to wait
for the answer anyway, and this would only a very little time while copying
the reply.
This means, that write() on the fuse device will not return -ENOENT during
normal operation, only if the filesystem is aborted by a forced umount or
through the fusectl interface.
This could simplify userspace code somewhat when backward compatibility with
earlier kernel versions is not required.
Miklos Szeredi [Wed, 17 Oct 2007 06:31:03 +0000 (23:31 -0700)]
fuse: fix permission checking on sticky directories
The VFS checks sticky bits on the parent directory even if the filesystem
defines it's own ->permission(). In some situations (sshfs, mountlo, etc) the
user does have permission to delete a file even if the attribute based
checking would not allow it.
So work around this by storing the permission bits separately and returning
them in stat(), but cutting the permission bits off from inode->i_mode.
This is slightly hackish, but it's probably not worth it to add new
infrastructure in VFS and a slight performance penalty for all filesystems,
just for the sake of fuse.
[Jan Engelhardt] cosmetic fixes Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Jan Engelhardt <jengelh@linux01.gwdg.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Miklos Szeredi [Wed, 17 Oct 2007 06:31:01 +0000 (23:31 -0700)]
fuse: fix page invalidation
Other than truncate, there are two cases, when fuse tries to get rid
of cached pages:
a) in open, if KEEP_CACHE flag is not set
b) in getattr, if file size changed spontaneously
Until now invalidate_mapping_pages() were used, which didn't get rid
of mapped pages. This is wrong, and becomes more wrong as dirty pages
are introduced. So instead properly invalidate all pages with
invalidate_inode_pages2().
Miklos Szeredi [Wed, 17 Oct 2007 06:31:00 +0000 (23:31 -0700)]
fuse: add reference counting to fuse_file
Make lifetime of 'struct fuse_file' independent from 'struct file' by adding a
reference counter and destructor.
This will enable asynchronous page writeback, where it cannot be guaranteed,
that the file is not released while a request with this file handle is being
served.
The actual RELEASE request is only sent when there are no more references to
the fuse_file.
Jesper Juhl [Wed, 17 Oct 2007 06:30:58 +0000 (23:30 -0700)]
floppy: remove register keyword use from floppy driver
The floppy drive is slow. These days I see absolutely no good reason why the
floppy driver should try to gain a tiny bit of speed by telling gcc to
optimize access to some variables via the register keyword. Better to just
leave gcc free to do whatever optimizations it deduces to be sane and not
hamper it by telling it that some variables in the floppy driver are special
and need to be fast (they don't).
Jesper Juhl [Wed, 17 Oct 2007 06:30:58 +0000 (23:30 -0700)]
floppy: remove dead/commented out code from floppy driver
A good initial step for a cleanup seems to me to be getting rid of old dead
code. This stuff is either commented out or inside '#if 0' so it is not
currently in use at all, let's just get rid of it once and for all. That's a
few lines less to deal with.
Jesper Juhl [Wed, 17 Oct 2007 06:30:57 +0000 (23:30 -0700)]
floppy: do a very minimal style cleanup of the floppy driver
Yes, some of this will likely be replaced in later patches, but I do not see
anyone else coming out of the woodwork with any patches for this driver, so
I'll ignore comments about churn. I want to get this driver cleaned up, and
if I'm going to do so I want to start with this basic style cleanup to reduce
the reading pain a bit.
Oleg Nesterov [Wed, 17 Oct 2007 06:30:56 +0000 (23:30 -0700)]
do CPU_DEAD migrating under read_lock(tasklist) instead of write_lock_irq(tasklist)
Currently move_task_off_dead_cpu() is called under
write_lock_irq(tasklist). This means it can't use task_lock() which is
needed to improve migrating to take task's ->cpuset into account.
Change the code to call move_task_off_dead_cpu() with irqs enabled, and
change migrate_live_tasks() to use read_lock(tasklist).
This all is a preparation for the futher changes proposed by Cliff Wickman, see
http://marc.info/?t=117327786100003
NeilBrown [Wed, 17 Oct 2007 06:30:55 +0000 (23:30 -0700)]
md: make sure read errors are auto-corrected during a 'check' resync in raid1
Whenever a read error is found, we should attempt to overwrite with correct
data to 'fix' it.
However when do a 'check' pass (which compares data blocks that are
successfully read, but doesn't normally overwrite) we don't do that. We
should.
Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Iustin Pop [Wed, 17 Oct 2007 06:30:54 +0000 (23:30 -0700)]
md: expose the degraded status of an assembled array through sysfs
The 'degraded' attribute is useful to quickly determine if the array is
degraded, instead of parsing 'mdadm -D' output or relying on the other
techniques (number of working devices against number of defined devices,
etc.). The md code already keeps track of this attribute, so it's useful to
export it.
Signed-off-by: Iustin Pop <iusty@k1024.org> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
NeilBrown [Wed, 17 Oct 2007 06:30:53 +0000 (23:30 -0700)]
md: 'sync_action' in sysfs returns wrong value for readonly arrays
When an array is started read-only, MD_RECOVERY_NEEDED can be set but no
recovery will be running. This causes 'sync_action' to report the wrong
value.
We could remove the test for MD_RECOVERY_NEEDED, but doing so would leave a
small gap after requesting a sync action, where 'sync_action' would still
report the old value.
So make sure that for a read-only array, 'sync_action' always returns 'idle'.
Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
NeilBrown [Wed, 17 Oct 2007 06:30:53 +0000 (23:30 -0700)]
md: fix a bug in some never-used code.
http://bugzilla.kernel.org/show_bug.cgi?id=3277
There is a seq_printf here that isn't being passed a 'seq'. Howeve as the
code is inside #ifdef MD_DEBUG, nobody noticed.
Also remove some extra spaces.
Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Adrian Bunk [Wed, 17 Oct 2007 06:30:52 +0000 (23:30 -0700)]
bitmap.h: remove dead artifacts
bitmap_active() no longer exists and BITMAP_ACTIVE is no longer used.
Signed-off-by: Adrian Bunk <bunk@kernel.org> Cc: Neil Brown <neilb@suse.de> Cc: "J. Bruce Fields" <bfields@fieldses.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michael J. Evans [Wed, 17 Oct 2007 06:30:52 +0000 (23:30 -0700)]
md: software Raid autodetect dev list not array
In current release kernels the md module (Software RAID) uses a static
array (dev_t[128]) to store partition/device info temporarily for
autostart.
I discovered this (and that the devices are added as disks/partitions are
discovered at boot) while I was debugging why only one of my MD arrays would
come up whole, while all the others were short a disk.
I eventually discovered that it was enumerating through all of 9 of my 11 hds
(2 had only 4 partitions apiece) while the other 9 have 15 partitions (I
wanted 64 per drive...). The last partition of the 8th drive in my 9 drive
raid 5 sets wasn't added, thus making the final md array short both a parity
and data disk, and it was started later, elsewhere.
This patch replaces that static array with a list.
[akpm@linux-foundation.org: removed unused var] Signed-off-by: Michael J. Evans <mjevans1983@gmail.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Joern Engel [Wed, 17 Oct 2007 06:30:44 +0000 (23:30 -0700)]
introduce I_SYNC
I_LOCK was used for several unrelated purposes, which caused deadlock
situations in certain filesystems as a side effect. One of the purposes
now uses the new I_SYNC bit.
Also document the various bits and change their order from historical to
logical.
[bunk@stusta.de: make fs/inode.c:wake_up_inode() static] Signed-off-by: Joern Engel <joern@wohnheim.fh-wedel.de> Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com> Cc: David Chinner <dgc@sgi.com> Cc: Anton Altaparmakov <aia21@cam.ac.uk> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fengguang Wu [Wed, 17 Oct 2007 06:30:43 +0000 (23:30 -0700)]
writeback: introduce writeback_control.more_io to indicate more io
After making dirty a 100M file, the normal behavior is to start the writeback
for all data after 30s delays. But sometimes the following happens instead:
- after 30s: ~4M
- after 5s: ~4M
- after 5s: all remaining 92M
Some analyze shows that the internal io dispatch queues goes like this:
1) initial state with a 100M file and a 1K file
2) 4M written, nr_to_write <= 0, so write more
3) 1K written, nr_to_write > 0, no more writes(BUG)
nr_to_write > 0 in (3) fools the upper layer to think that data have all been
written out. The big dirty file is actually still sitting in s_more_io. We
cannot simply splice s_more_io back to s_io as soon as s_io becomes empty, and
let the loop in generic_sync_sb_inodes() continue: this may starve newly
expired inodes in s_dirty. It is also not an option to draw inodes from both
s_more_io and s_dirty, an let the loop go on: this might lead to live locks,
and might also starve other superblocks in sync time(well kupdate may still
starve some superblocks, that's another bug).
We have to return when a full scan of s_io completes. So nr_to_write > 0 does
not necessarily mean that "all data are written". This patch introduces a
flag writeback_control.more_io to indicate this situation. With it the big
dirty file no longer has to wait for the next kupdate invocation 5s later.
Cc: David Chinner <dgc@sgi.com> Cc: Ken Chen <kenchen@google.com> Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fengguang Wu [Wed, 17 Oct 2007 06:30:42 +0000 (23:30 -0700)]
writeback: remove pages_skipped accounting in __block_write_full_page()
Miklos Szeredi <miklos@szeredi.hu> and me identified a writeback bug:
> The following strange behavior can be observed:
>
> 1. large file is written
> 2. after 30 seconds, nr_dirty goes down by 1024
> 3. then for some time (< 30 sec) nothing happens (disk idle)
> 4. then nr_dirty again goes down by 1024
> 5. repeat from 3. until whole file is written
>
> So basically a 4Mbyte chunk of the file is written every 30 seconds.
> I'm quite sure this is not the intended behavior.
% dmesg|grep 847824 # generated by a debug printk
[ 529.263184] redirtied inode 847824 line 548
[ 564.250872] redirtied inode 847824 line 548
[ 594.272797] redirtied inode 847824 line 548
[ 629.231330] redirtied inode 847824 line 548
[ 659.224674] redirtied inode 847824 line 548
[ 689.219890] redirtied inode 847824 line 548
[ 724.226655] redirtied inode 847824 line 548
[ 759.198568] redirtied inode 847824 line 548
# line 548 in fs/fs-writeback.c:
543 if (wbc->pages_skipped != pages_skipped) {
544 /*
545 * writeback is not making progress due to locked
546 * buffers. Skip this inode for now.
547 */
548 redirty_tail(inode);
549 }
More debug efforts show that __block_write_full_page()
never has the chance to call submit_bh() for that big dirty file:
the buffer head is *clean*. So basicly no page io is issued by
__block_write_full_page(), hence pages_skipped goes up.
Also the comment in generic_sync_sb_inodes():
544 /*
545 * writeback is not making progress due to locked
546 * buffers. Skip this inode for now.
547 */
and the comment in __block_write_full_page():
1713 /*
1714 * The page was marked dirty, but the buffers were
1715 * clean. Someone wrote them back by hand with
1716 * ll_rw_block/submit_bh. A rare case.
1717 */
do not quite agree with each other. The page writeback should be skipped for
'locked buffer', but here it is 'clean buffer'!
This patch fixes this bug. Though I'm not sure why __block_write_full_page()
is called only to do nothing and who actually issued the writeback for us.
This is the two possible new behaviors after the patch:
1) pretty nice: wait 30s and write ALL:)
2) not so good:
- during the dd: ~16M
- after 30s: ~4M
- after 5s: ~4M
- after 5s: ~176M
The next patch will fix case (2).
Cc: David Chinner <dgc@sgi.com> Cc: Ken Chen <kenchen@google.com> Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Signed-off-by: David Chinner <dgc@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fengguang Wu [Wed, 17 Oct 2007 06:30:39 +0000 (23:30 -0700)]
writeback: fix time ordering of the per superblock inode lists 8
Streamline the management of dirty inode lists and fix time ordering bugs.
The writeback logic used to move not-yet-expired dirty inodes from s_dirty to
s_io, *only to* move them back. The move-inodes-back-and-forth thing is a
mess, which is eliminated by this patch.
The new scheme is:
- s_dirty acts as a time ordered io delaying queue;
- s_io/s_more_io together acts as an io dispatching queue.
On kupdate writeback, we pull some inodes from s_dirty to s_io at the start of
every full scan of s_io. Otherwise (i.e. for sync/throttle/background
writeback), we always pull from s_dirty on each run (a partial scan).
Note that the line
list_splice_init(&sb->s_more_io, &sb->s_io);
is moved to queue_io() to leave s_io empty. Otherwise a big dirtied file will
sit in s_io for a long time, preventing new expired inodes to get in.
Cc: Ken Chen <kenchen@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Current -mm tree has bucketful of bug fixes in periodic writeback path.
However, we still hit a glitch where dirty pages on a given inode aren't
completely flushed to the disk, and system will accumulate large amount of
dirty pages beyond what dirty_expire_interval is designed for.
The problem is __sync_single_inode() will move an inode to sb->s_dirty list
even when there are more pending dirty pages on that inode. If there is
another inode with a small number of dirty pages, we hit a case where the loop
iteration in wb_kupdate() terminates prematurely because wbc.nr_to_write > 0.
Thus leaving the inode that has large amount of dirty pages behind and it has
to wait for another dirty_writeback_interval before we flush it again. We
effectively only write out MAX_WRITEBACK_PAGES every dirty_writeback_interval.
If the rate of dirtying is sufficiently high, the system will start
accumulate a large number of dirty pages.
So fix it by having another sb->s_more_io list on which to park the inode
while we iterate through sb->s_io and to allow each dirty inode which resides
on that sb to have an equal chance of flushing some amount of dirty pages.
Signed-off-by: Ken Chen <kenchen@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrew Morton [Wed, 17 Oct 2007 06:30:37 +0000 (23:30 -0700)]
writeback: fix time ordering of the per superblock dirty inode lists 7
This one fixes four bugs.
There are a few situation in there where writeback decides it is going to skip
over a blockdev inode on the kernel-internal blockdev superblock. It
presently does this by moving the blockdev inode onto the tail of the blockdev
superblock's s_dirty. But
a) this screws up s_dirty's reverse-time-orderedness and
b) refiling the blockdev for writeback in another 30 second is rude. We
should try again sooner than that.
Fix all this up by using redirty_head(): move the blockdev inode onto the head
of the blockdev superblock's s_dirty list for prompt writeback.
Cc: Mike Waychison <mikew@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrew Morton [Wed, 17 Oct 2007 06:30:37 +0000 (23:30 -0700)]
writeback: fix time ordering of the per superblock dirty inode lists 6
Recycling the previous changelog:
When the writeback function is operating in writeback-for-flushing mode
(as opposed to writeback-for-integrity) and it encounters an I_LOCKed inode,
it will skip writing that inode. This is done for throughput and latency:
move on to another inode rather than blocking for this one.
Writeback skips this inode by moving it off s_io and onto s_dirty, so that
writeback can proceed with the other inodes on s_io.
However that inode movement can corrupt s_dirty's
reverse-time-orderedness. Fix that by using the new redirty_tail(), which
will update the refiled inode's dirtied_when field.
Note: the behaviour in here is a bit rude: if kupdate happens to come
across a locked inode then it will defer writeback of that inode for another
30 seconds. We'll address that in the next patch.
Address that here. What we do is to move the skipped inode to the _head_ of
s_dirty, immediately eligible for writeout again. Instead of deferring that
writeout for another 30 seconds.
One would think that this might cause a livelock: we keep on trying to write
the same locked inode. But it won't because:
a) if that was the case, it would _already_ be happening on the
balance_dirty_pages codepath. Because balance_dirty_pages() doesn't care
about inode timestamps.
b) if we skipped this inode then we won't have done any writeback. The
higher-level writeback paths will see that wbc.nr_to_write didn't change
and they'll then back off and take a nap.
Cc: Mike Waychison <mikew@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
projects / linux-2.6 / log