There is a lot of common code that could be shared between the m68k
and m68knommu arch branches. It makes sense to merge the two branches
into a single directory structure so that we can more easily share
that common code.
This is a brute force merge, based on a script from Stephen King
<sfking@fdwdc.com>, which was originally written by Arnd Bergmann
<arnd@arndb.de>.
> The script was inspired by the script Sam Ravnborg used to merge the
> includes from m68knommu. For those files common to both arches but
> differing in content, the m68k version of the file is renamed to
> <file>_mm.<ext> and the m68knommu version of the file is moved into the
> corresponding m68k directory and renamed <file>_no.<ext> and a small
> wrapper file <file>.<ext> is used to select between the two version. Files
> that are common to both but don't differ are removed from the m68knommu
> tree and files and directories that are unique to the m68knommu tree are
> moved to the m68k tree. Finally, the arch/m68knommu tree is removed.
>
> To select between the the versions of the files, the wrapper uses
>
> #ifdef CONFIG_MMU
> #include <file>_mm.<ext>
> #else
> #include <file>_no.<ext>
> #endif
On top of this file merge I have done a simplistic merge of m68k and
m68knommu Kconfig, which primarily attempts to keep existing options and
menus in place. Other than a handful of options being moved it produces
identical .config outputs on m68k and m68knommu targets I tested it on.
With this in place there is now quite a bit of scope for merge cleanups
in future patches.
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
fs: simplify iget & friends
fs: pull inode->i_lock up out of writeback_single_inode
fs: rename inode_lock to inode_hash_lock
fs: move i_wb_list out from under inode_lock
fs: move i_sb_list out from under inode_lock
fs: remove inode_lock from iput_final and prune_icache
fs: Lock the inode LRU list separately
fs: factor inode disposal
fs: protect inode->i_state with inode->i_lock
autofs4: Do not potentially dereference NULL pointer returned by fget() in autofs_dev_ioctl_setpipefd()
autofs4 - remove autofs4_lock
autofs4 - fix d_manage() return on rcu-walk
autofs4 - fix autofs4_expire_indirect() traversal
autofs4 - fix dentry leak in autofs4_expire_direct()
autofs4 - reinstate last used update on access
vfs - check non-mountpoint dentry might block in __follow_mount_rcu()
Fix the following compile failure:
drivers/media/rc/ite-cir.c: In function 'ite_decode_bytes':
drivers/media/rc/ite-cir.c:190: error: implicit declaration of function 'generic_find_next_le_bit'
drivers/media/rc/ite-cir.c:199: error: implicit declaration of function 'generic_find_next_zero_le_bit'
Caused by commit 620a32bba4 ("[media] rc: New rc-based ite-cir driver
for several ITE CIRs") interacting with commit c4945b9ed4
("asm-generic: rename generic little-endian bitops functions").
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge get_new_inode/get_new_inode_fast into iget5_locked/iget_locked
as those were the only callers. Remove the internal ifind/ifind_fast
helpers - ifind_fast only had a single caller, and ifind had two
callers wanting it to do different things. Also clean up the comments
in this area to focus on information important to a developer trying
to use it, instead of overloading them with implementation details.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
First thing we do in writeback_single_inode() is take the i_lock and
the last thing we do is drop it. A caller already holds the i_lock,
so pull the i_lock out of writeback_single_inode() to reduce the
round trips on this lock during inode writeback.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
All that remains of the inode_lock is protecting the inode hash list
manipulation and traversals. Rename the inode_lock to
inode_hash_lock to reflect it's actual function.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Protect the inode writeback list with a new global lock
inode_wb_list_lock and use it to protect the list manipulations and
traversals. This lock replaces the inode_lock as the inodes on the
list can be validity checked while holding the inode->i_lock and
hence the inode_lock is no longer needed to protect the list.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Protect the per-sb inode list with a new global lock
inode_sb_list_lock and use it to protect the list manipulations and
traversals. This lock replaces the inode_lock as the inodes on the
list can be validity checked while holding the inode->i_lock and
hence the inode_lock is no longer needed to protect the list.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Now that inode state changes are protected by the inode->i_lock and
the inode LRU manipulations by the inode_lru_lock, we can remove the
inode_lock from prune_icache and the initial part of iput_final().
instead of using the inode_lock to protect the inode during
iput_final, use the inode->i_lock instead. This protects the inode
against new references being taken while we change the inode state
to I_FREEING, as well as preventing prune_icache from grabbing the
inode while we are manipulating it. Hence we no longer need the
inode_lock in iput_final prior to setting I_FREEING on the inode.
For prune_icache, we no longer need the inode_lock to protect the
LRU list, and the inodes themselves are protected against freeing
races by the inode->i_lock. Hence we can lift the inode_lock from
prune_icache as well.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Introduce the inode_lru_lock to protect the inode_lru list. This
lock is nested inside the inode->i_lock to allow the inode to be
added to the LRU list in iput_final without needing to deal with
lock inversions. This keeps iput_final() clean and neat.
Further, where marking the inode I_FREEING and removing it from the
LRU, move the LRU list manipulation within the inode->i_lock to keep
the list manipulation consistent with iput_final. This also means
that most of the open coded LRU list removal + unused inode
accounting can now use the inode_lru_list_del() wrappers which
cleans the code up further.
However, this locking change means what the LRU traversal in
prune_icache() inverts this lock ordering and needs to use trylock
semantics on the inode->i_lock to avoid deadlocking. In these cases,
if we fail to lock the inode we move it to the back of the LRU to
prevent spinning on it.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We have a couple of places that dispose of inodes. factor the
disposal into evict() to isolate this code and make it simpler to
peel away the inode_lock from the code.
While doing this, change the logic flow in iput_final() to separate
the different cases that need to be handled to make the transitions
the inode goes through more obvious.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Protect inode state transitions and validity checks with the
inode->i_lock. This enables us to make inode state transitions
independently of the inode_lock and is the first step to peeling
away the inode_lock from the code.
This requires that __iget() is done atomically with i_state checks
during list traversals so that we don't race with another thread
marking the inode I_FREEING between the state check and grabbing the
reference.
Also remove the unlock_new_inode() memory barrier optimisation
required to avoid taking the inode_lock when clearing I_NEW.
Simplify the code by simply taking the inode->i_lock around the
state change and wakeup. Because the wakeup is no longer tricky,
remove the wake_up_inode() function and open code the wakeup where
necessary.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* 'slab/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6:
SLUB: Write to per cpu data when allocating it
slub: Fix debugobjects with lockless fastpath
Commit ddd588b5dd ("oom: suppress nodes that are not allowed from
meminfo on oom kill") moved lib/show_mem.o out of lib/lib.a, which
resulted in build warnings on all architectures that implement their own
versions of show_mem():
lib/lib.a(show_mem.o): In function `show_mem':
show_mem.c:(.text+0x1f4): multiple definition of `show_mem'
arch/sparc/mm/built-in.o:(.text+0xd70): first defined here
The fix is to remove __show_mem() and add its argument to show_mem() in
all implementations to prevent this breakage.
Architectures that implement their own show_mem() actually don't do
anything with the argument yet, but they could be made to filter nodes
that aren't allowed in the current context in the future just like the
generic implementation.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: James Bottomley <James.Bottomley@hansenpartnership.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'drm-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6:
drm/vblank: update recently added vbl interface to be more future proof.
drm radeon: Return -EINVAL on wrong pm sysfs access
drm/radeon/kms: fix hardcoded EDID handling
Revert "drm/i915: Don't save/restore hardware status page address register"
drm/i915: Avoid unmapping pages from a NULL address space
drm/i915: Fix use after free within tracepoint
drm/i915: Restore missing command flush before interrupt on BLT ring
drm/i915: Disable pagefaults along execbuffer relocation fast path
drm/i915: Fix computation of pitch for dumb bo creator
drm/i915: report correct render clock frequencies on SNB
drm/i915/dp: Correct the order of deletion for ghost eDP devices
drm/i915: Fix tiling corruption from pipelined fencing
drm/i915: Re-enable self-refresh
drm/i915: Prevent racy removal of request from client list
drm/i915: skip redundant operations whilst enabling pipes and planes
drm/i915: Remove surplus POSTING_READs before wait_for_vblank
drm/radeon/kms: prefer legacy pll algo for tv-out
drm: check for modesetting on modeset ioctls
drm/kernel: vblank wait on crtc > 1
drm: Fix use-after-free in drm_gem_vm_close()
It turns out that the cmpxchg16b emulation has to access vmalloced
percpu memory with interrupts disabled. If the memory has never
been touched before then the fault necessary to establish the
mapping will not to occur and the kernel will fail on boot.
Fix that by reusing the CONFIG_PREEMPT code that writes the
cpu number into a field on every cpu. Writing to the per cpu
area before causes the mapping to be established before we get
to a cmpxchg16b emulation.
Tested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
On Thu, 24 Mar 2011, Ingo Molnar wrote:
> RIP: 0010:[<ffffffff810570a9>] [<ffffffff810570a9>] get_next_timer_interrupt+0x119/0x260
That's a typical timer crash, but you were unable to debug it with
debugobjects because commit d3f661d6 broke those.
Cc: Christoph Lameter <cl@linux.com>
Tested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
In fs/autofs4/dev-ioctl.c::autofs_dev_ioctl_setpipefd() we call fget(),
which may return NULL, but we do not explicitly test for that NULL return
so we may end up dereferencing a NULL pointer - bad.
When I originally submitted this patch I had chosen EBUSY as the return
value to use if this happens. Ian Kent was kind enough to explain why that
would most likely be wrong and why EBADF should most likely be used
instead. This version of the patch uses EBADF.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The autofs4_lock introduced by the rcu-walk changes has unnecessarily
broad scope. The locking is better handled by the per-autofs super
block lookup_lock.
Signed-off-by: Ian Kent <raven@themaw.net>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The daemon never needs to block and, in the rcu-walk case an error
return isn't used, so always return zero.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The vfs-scale changes changed the traversal used in
autofs4_expire_indirect() from a list to a depth first tree traversal
which isn't right.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
There is a missing dput() when returning from autofs4_expire_direct()
when we see that the dentry is already a pending mount.
Signed-off-by: Ian Kent <raven@themaw.net>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When direct (and offset) mounts were introduced the the last used
timeout could no longer be updated in ->d_revalidate(). This is
because covered direct mounts would be followed over without calling
the autofs file system. As a result the definition of the busyness
check for all entries was changed to be "actually busy" being an open
file or working directory within the automount. But now we have a call
back in the follow so the last used update on any access can be
re-instated. This requires DCACHE_MANAGE_TRANSIT to always be set.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When following a mount in rcu-walk mode we must check if the incoming dentry
is telling us it may need to block, even if it isn't actually a mountpoint.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block: (65 commits)
Documentation/iostats.txt: bit-size reference etc.
cfq-iosched: removing unnecessary think time checking
cfq-iosched: Don't clear queue stats when preempt.
blk-throttle: Reset group slice when limits are changed
blk-cgroup: Only give unaccounted_time under debug
cfq-iosched: Don't set active queue in preempt
block: fix non-atomic access to genhd inflight structures
block: attempt to merge with existing requests on plug flush
block: NULL dereference on error path in __blkdev_get()
cfq-iosched: Don't update group weights when on service tree
fs: assign sb->s_bdi to default_backing_dev_info if the bdi is going away
block: Require subsystems to explicitly allocate bio_set integrity mempool
jbd2: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging
jbd: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging
fs: make fsync_buffers_list() plug
mm: make generic_writepages() use plugging
blk-cgroup: Add unaccounted time to timeslice_used.
block: fixup plugging stubs for !CONFIG_BLOCK
block: remove obsolete comments for blkdev_issue_zeroout.
blktrace: Use rq->cmd_flags directly in blk_add_trace_rq.
...
Fix up conflicts in fs/{aio.c,super.c}
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-mn10300:
MN10300: gcc 4.6 vs am33 inline assembly
MN10300: Deprecate gdbstub
MN10300: Allow KGDB to use the MN10300 serial ports
MN10300: Emulate single stepping in KGDB on MN10300
MN10300: Generalise kernel debugger kernel halt, reboot or power off hook
KGDB: Notify GDB of machine halt, reboot or power off
MN10300: Use KGDB
MN10300: Create generic kernel debugger hooks
MN10300: Create general kernel debugger cache flushing
MN10300: Introduce a general config option for kernel debugger hooks
MN10300: The icache invalidate functions should disable the icache first
MN10300: gdbstub: Restrict single-stepping to non-preemptable non-SMP configs
* 'rmobile-latest' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6:
mmc: Add MMC_PROGRESS_*
mmc, ARM: Rename SuperH Mobile ARM zboot helpers
ARM: mach-shmobile: add coherent DMA mask to CEU camera devices
ARM: mach-shmobile: Dynamic backlight control for Mackerel
* 'usb-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6:
USB: cdc-acm: fix potential null-pointer dereference on disconnect
USB: cdc-acm: fix potential null-pointer dereference
USB: cdc-acm: fix memory corruption / panic
USB: Fix 'bad dma' problem on WDM device disconnect
usb: wwan: fix compilation without CONFIG_PM_RUNTIME
USB: uss720 fixup refcount position
usb: musb: blackfin: fix typo in new bfin_musb_vbus_status func
usb: musb: blackfin: fix typo in new dev_pm_ops struct
usb: musb: blackfin: fix typo in platform driver name
usb: musb: Fix for merge issue
ehci-hcd: Bug fix: don't set a QH's Halt bit
USB: Do not pass negative length to snoop_urb()
* 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6: (442 commits)
[media] videobuf2-dma-contig: make cookie() return a pointer to dma_addr_t
[media] sh_mobile_ceu_camera: Do not call vb2's mem_ops directly
[media] V4L: soc-camera: explicitly require V4L2_BUF_TYPE_VIDEO_CAPTURE
[media] v4l: soc-camera: Store negotiated buffer settings
[media] rc: interim support for 32-bit NEC-ish scancodes
[media] mceusb: topseed 0x0011 needs gen3 init for tx to work
[media] lirc_zilog: error out if buffer read bytes != chunk size
[media] lirc: silence some compile warnings
[media] hdpvr: use same polling interval as other OS
[media] ir-kbd-i2c: pass device code w/key in hauppauge case
[media] rc/keymaps: Remove the obsolete rc-rc5-tv keymap
[media] remove the old RC_MAP_HAUPPAUGE_NEW RC map
[media] rc/keymaps: Rename Hauppauge table as rc-hauppauge
[media] rc-rc5-hauppauge-new: Fix Hauppauge Grey mapping
[media] rc-rc5-hauppauge-new: Add support for the old Black RC
[media] rc-rc5-hauppauge-new: Add the old control to the table
[media] rc-winfast: Fix the keycode tables
[media] a800: Fix a few wrong IR key assignments
[media] opera1: Use multimedia keys instead of an app-specific mapping
[media] dw2102: Use multimedia keys instead of an app-specific mapping
...
Fix up trivial conflicts (remove/modify and some real conflicts) in:
arch/arm/mach-omap2/devices.c
drivers/staging/Kconfig
drivers/staging/Makefile
drivers/staging/dabusb/dabusb.c
drivers/staging/dabusb/dabusb.h
drivers/staging/easycap/easycap_ioctl.c
drivers/staging/usbvideo/usbvideo.c
drivers/staging/usbvideo/vicam.c
* 'devicetree/merge' of git://git.secretlab.ca/git/linux-2.6:
spi/pl022: Add loopback support for the SPI on 5500
spi/omap_mcspi: Fix broken last word xfer
of/flattree: minor cleanups
dt: eliminate OF_NO_DEEP_PROBE and test for NULL match table
dt: protect against NULL matches passed to of_match_node()
dt: Refactor of_platform_bus_probe()
This is my second attempt to make this enum generally available.
The first attempt added MMCIF_PROGRESS_* to include/linux/mmc/sh_mmcif.h.
However this is not sufficiently generic as the enum will be
used by SDHI boot code.
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
These headers and helpers will also be used for SDHI boot
so the mmcif name will start to make a lot less sense.
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: (42 commits)
ACPI: minor printk format change in acpi_pad
ACPI: make acpi_pad /sys output more readable
ACPICA: Update version to 20110316
ACPICA: Header support for SLIC table
ACPI: Make sure the FADT is at least rev 2 before using the reset register
ACPI: Bug compatibility for Windows on the ACPI reboot vector
ACPICA: Fix access width for reset vector
ACPI battery: fribble sysfs files from a resume notifier
ACPI button: remove unused procfs I/F
ACPI, APEI, Add PCIe AER error information printing support
PCIe, AER, use pre-generated prefix in error information printing
ACPI, APEI, Add ERST record ID cache
ACPI: Use syscore_ops instead of sysdev class and sysdev
ACPI: Remove the unused EC sysdev class
ACPI: use __cpuinit for the acpi_processor_set_pdc() call tree
ACPI: use __init where possible in processor driver
Thermal_Framework-Fix_crash_during_hwmon_unregister
ACPICA: Update version to 20110211.
ACPICA: Add mechanism to defer _REG methods for some installed handlers
ACPICA: Add support for FunctionalFixedHW in acpi_ut_get_region_name
...
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/vapier/blackfin:
Blackfin: bf54x: re-enable anomaly 05000353 for all revs
Blackfin: enable atomic64_t support
Blackfin: wire up new syncfs syscall
Blackfin: SMP: flush CoreB cache when shutting down
* 'for-2.6.39' of git://linux-nfs.org/~bfields/linux:
SUNRPC: Remove resource leak in svc_rdma_send_error()
nfsd: wrong index used in inner loop
nfsd4: fix comment and remove unused nfsd4_file fields
nfs41: make sure nfs server return right ca_maxresponsesize_cached
nfsd: fix compile error
svcrpc: fix bad argument in unix_domain_find
nfsd4: fix struct file leak
nfsd4: minor nfs4state.c reshuffling
svcrpc: fix rare race on unix_domain creation
nfsd41: modify the members value of nfsd4_op_flags
nfsd: add proc file listing kernel's gss_krb5 enctypes
gss:krb5 only include enctype numbers in gm_upcall_enctypes
NFSD, VFS: Remove dead code in nfsd_rename()
nfsd: kill unused macro definition
locks: use assign_type()
* git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-linus:
Squashfs: Use vmalloc rather than kmalloc for zlib workspace
Squashfs: handle corruption of directory structure
Squashfs: wrap squashfs_mount() definition
Squashfs: xz_wrapper doesn't need to include squashfs_fs_i.h anymore
Squashfs: Update documentation to include compression options
Squashfs: Update Kconfig help text to include xz compression
Squashfs: add compression options support to xz decompressor
Squashfs: extend decompressor framework to handle compression options
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband:
IB: Increase DMA max_segment_size on Mellanox hardware
IB/mad: Improve an error message so error code is included
RDMA/nes: Don't print success message at level KERN_ERR
RDMA/addr: Fix return of uninitialized ret value
IB/srp: try to use larger FMR sizes to cover our mappings
IB/srp: add support for indirect tables that don't fit in SRP_CMD
IB/srp: rework mapping engine to use multiple FMR entries
IB/srp: allow sg_tablesize to be set for each target
IB/srp: move IB CM setup completion into its own function
IB/srp: always avoid non-zero offsets into an FMR
* 'for-linus' of git://git.open-osd.org/linux-open-osd:
exofs: deprecate the commands pending counter
exofs: Write sbi->s_nextid as part of the Create command
exofs: Add option to mount by osdname
exofs: Override read-ahead to align on stripe_size
exofs: simple fsync race fix
exofs: Optimize read_4_write
exofs: Trivial: fix some indentation and debug prints
exofs: Remove redundant unlikely()
This patch fixes the following UBIFS assertion warning:
UBIFS assert failed in do_readpage at 115 (pid 199)
[<b00321b8>] (unwind_backtrace+0x0/0xdc) from [<af025118>]
(do_readpage+0x108/0x594 [ubifs])
[<af025118>] (do_readpage+0x108/0x594 [ubifs]) from [<af025764>]
(ubifs_write_end+0x1c0/0x2e8 [ubifs])
[<af025764>] (ubifs_write_end+0x1c0/0x2e8 [ubifs]) from
[<b00a0164>] (generic_file_buffered_write+0x18c/0x270)
[<b00a0164>] (generic_file_buffered_write+0x18c/0x270) from
[<b00a08d4>] (__generic_file_aio_write+0x478/0x4c0)
[<b00a08d4>] (__generic_file_aio_write+0x478/0x4c0) from
[<b00a0984>] (generic_file_aio_write+0x68/0xc8)
[<b00a0984>] (generic_file_aio_write+0x68/0xc8) from
[<af024a78>] (ubifs_aio_write+0x178/0x1d8 [ubifs])
[<af024a78>] (ubifs_aio_write+0x178/0x1d8 [ubifs]) from
[<b00d104c>] (do_sync_write+0xb0/0x100)
[<b00d104c>] (do_sync_write+0xb0/0x100) from [<b00d1abc>]
(vfs_write+0xac/0x154)
[<b00d1abc>] (vfs_write+0xac/0x154) from [<b00d1c10>]
(sys_write+0x3c/0x68)
[<b00d1c10>] (sys_write+0x3c/0x68) from [<b002d9a0>]
(ret_fast_syscall+0x0/0x2c)
The 'PG_checked' flag is used to indicate that the page does not
supposedly exist on the media (e.g., a hole or a page beyond the
inode size), so it requires slightly bigger budget, because we have
to account the indexing size increase. And this flag basically
tells that the budget for this page has to be "new page budget".
The "new page budget" is slightly bigger than the "existing page
budget".
The 'do_readpage()' function has the following assertion which
sometimes is hit: 'ubifs_assert(!PageChecked(page))'. Obviously,
the meaning of this assertion is: "I should not be asked to read
a page which does not exist on the media".
However, in 'ubifs_write_begin()' we have a small "trick". Notice,
that VFS may write pages which were not read yet, so the page data
were not loaded from the media to the page cache yet. If VFS tells
that it is going to change only some part of the page, we obviously
have to load it from the media. However, if VFS tells that it is
going to change whole page, we do not read it from the media for
optimization purposes.
However, since we do not read it, we do not know if it exists on
the media or not (a hole, etc). So we set the 'PG_checked' flag
to this page to force bigger budget, just in case.
So 'ubifs_write_begin()' sets 'PG_checked'. Then we are in
'ubifs_write_end()'. And VFS tells us: "hey, for some reasons I
changed my mind and did not change whole page". Frankly, I do not
know why this happens, but I hit this somehow on an ARM platform.
And this is extremely rare.
So in this case UBIFS does the following:
1. Cancels allocated budget.
2. Loads the page from the media by calling 'do_readpage()'.
3. Asks VFS to repeat the whole write operation from the very
beginning (call '->write_begin() again, etc).
And the assertion warning is hit at the step 2 - remember we have
the 'PG_checked' set for this page, and 'do_readpage()' does not
like this. So this patch fixes the problem by adding step 1.5 and
cleaning the 'PG_checked' before calling 'do_readpage()'.
All in all, this patch does not fix any functionality issue, but it
silences UBIFS false positive warning which may happen in very very
rare cases.
And while on it, this patch also improves a commentary which explains
the reasons of setting the 'PG_checked' flag for the page. The old
commentary was a bit difficult to understand.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Simplify UBIFS configuration menu and kill the option to enable self-check
compile-time. We do not really need this because we can do this run-time
using the module parameters or the corresponding sysfs interfaces. And
there is a value in simplifying the kernel configuration menu which becomes
increasingly large.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
This patch fixes a brown-paperbag bug which was introduced by me:
I used incorrect "GFP_KERNEL | GFP_NOFS" allocation flags to make
sure my allocations do not cause write-back. But the correct form
is "GFP_NOFS".
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
This patch fixes a brown-paperbag bug which was introduced by me:
I used incorrect "GFP_KERNEL | GFP_NOFS" allocation flags to make
sure my allocations do not cause write-back. But the correct form
is "GFP_NOFS".
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
This makes the interface a bit cleaner by leaving a single gap in the
vblank bit space instead of creating two gaps.
Suggestions from Michel on mailing list/irc.
Reviewed-by: Michel Dänzer <michel@daenzer.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
