In commit a8e7d49aa7 ("Fix race in
create_empty_buffers() vs __set_page_dirty_buffers()"), I removed a test
for a NULL page mapping unintentionally when some of the code inside
__set_page_dirty() was moved to the callers.
That removal generally didn't matter, since a filesystem would serialize
truncation (which clears the page mapping) against writing (which marks
the buffer dirty), so locking at a higher level (either per-page or an
inode at a time) should mean that the buffer page would be stable. And
indeed, nothing bad seemed to happen.
Except it turns out that apparently reiserfs does something odd when
under load and writing out the journal, and we have a number of bugzilla
entries that look similar:
http://bugzilla.kernel.org/show_bug.cgi?id=13556http://bugzilla.kernel.org/show_bug.cgi?id=13756http://bugzilla.kernel.org/show_bug.cgi?id=13876
and it looks like reiserfs depended on that check (the common theme
seems to be "data=journal", and a journal writeback during a truncate).
I suspect reiserfs should have some additional locking, but in the
meantime this should get us back to the pre-2.6.29 behavior.
Pattern-pointed-out-by: Roland Kletzing <devzero@web.de>
Cc: stable@kernel.org (2.6.29 and 2.6.30)
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6:
drm/radeon: add GET_PARAM/INFO support for Z pipes
drm/radeon/kms: add r100/r200 OQ support.
drm: Fix sysfs device confusion.
drm/radeon/kms: implement the bo busy ioctl properly.
As noted in 83d349f35e ("x86: don't send
an IPI to the empty set of CPU's"), some APIC's will be very unhappy
with an empty destination mask. That commit added a WARN_ON() for that
case, and avoided the resulting problem, but didn't fix the underlying
reason for why those empty mask cases happened.
This fixes that, by checking the result of 'cpumask_andnot()' of the
current CPU actually has any other CPU's left in the set of CPU's to be
sent a TLB flush, and not calling down to the IPI code if the mask is
empty.
The reason this started happening at all is that we started passing just
the CPU mask pointers around in commit 4595f9620 ("x86: change
flush_tlb_others to take a const struct cpumask"), and when we did that,
the cpumask was no longer thread-local.
Before that commit, flush_tlb_mm() used to create it's own copy of
'mm->cpu_vm_mask' and pass that copy down to the low-level flush
routines after having tested that it was not empty. But after changing
it to just pass down the CPU mask pointer, the lower level TLB flush
routines would now get a pointer to that 'mm->cpu_vm_mask', and that
could still change - and become empty - after the test due to other
CPU's having flushed their own TLB's.
See
http://bugzilla.kernel.org/show_bug.cgi?id=13933
for details.
Tested-by: Thomas Björnell <thomas.bjornell@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When 'and'ing two bitmasks (where 'andnot' is a variation on it), some
cases want to know whether the result is the empty set or not. In
particular, the TLB IPI sending code wants to do cpumask operations and
determine if there are any CPU's left in the final set.
So this just makes the bitmask (and cpumask) functions return a boolean
for whether the result has any bits set.
Cc: stable@kernel.org (2.6.30, needed by TLB shootdown fix)
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The default_send_IPI_mask_logical() function uses the "flat" APIC mode
to send an IPI to a set of CPU's at once, but if that set happens to be
empty, some older local APIC's will apparently be rather unhappy. So
just warn if a caller gives us an empty mask, and ignore it.
This fixes a regression in 2.6.30.x, due to commit 4595f9620 ("x86:
change flush_tlb_others to take a const struct cpumask"), documented
here:
http://bugzilla.kernel.org/show_bug.cgi?id=13933
which causes a silent lock-up. It only seems to happen on PPro, P2, P3
and Athlon XP cores. Most developers sadly (or not so sadly, if you're
a developer..) have more modern CPU's. Also, on x86-64 we don't use the
flat APIC mode, so it would never trigger there even if the APIC didn't
like sending an empty IPI mask.
Reported-by: Pavel Vilim <wylda@volny.cz>
Reported-and-tested-by: Thomas Björnell <thomas.bjornell@gmail.com>
Reported-and-tested-by: Martin Rogge <marogge@onlinehome.de>
Cc: Mike Travis <travis@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Node may not be inserted over existing node. This causes inode tree
corruption and I was seeing crashes in inode_tree_del which I can not
reproduce after this patch.
The other way to fix this would be to tie inode lifetime in the rbtree
with inode while not in freeing state. I had a look at this but it is
not so trivial at this point. At least this patch gets things working again.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Chris Mason <chris.mason@oracle.com>
Acked-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
The drm sysfs class suspend / resume methods could not distinguish
between different device types wich could lead to illegal type casts.
Use struct device_type and make sure the class suspend / resume callbacks
are aware of those. There is no per device-type suspend / resume. Only
new-style PM.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
The previous patch assumes the ioctl already existed, when
it actually didn't.
It also didn't return the correct error code.
Signed-off-by: Dave Airlie <airlied@redhat.com>
* 'i2c-fixes-rc6' of git://aeryn.fluff.org.uk/bjdooks/linux:
i2c-stu300: I2C STU300 stability updates
i2c-omap: Enable workaround for Errata 1.153 based on
i2c-omap: ACK pending [R/X]DR and [R/X]RDY interrupts
i2c-omap: Fix I2C status ACK
- blk clk is enabled when an irq arrives. The clk should be enabled,
but just to make sure.
- All error bits are handled no matter state machine state
- All irq's will run complete() except for irq's that wasn't an event.
- No more looking into status registers just in case an interrupt
has happend and the irq handle wasn't executed.
- irq_disable/enable are now separete functions.
- clk settings calculation changed to round upwards instead of
downwards.
- Number of address send attempts before giving up is increased to 12
from 10 since it most times take 8 tries before getting through.
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Silicon Errata 1.153 has been fixed on OMAP 3630|4430 with the use of a later
version of I2C IP block.
The errata impacts OMAP 2420|2430|3430, enable the workaround for these based
on I2C IP block revision number instead of OMAP CPU type
Signed-off-by: Moiz Sonasath <m-sonasath@ti.com>
Signed-off-by: Vikram Pandita <vikram.pandita@ti.com
Reviewed-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
ACK any pending read/write interrupts before exiting the ISR either after
completing the operation [ARDY interrupt] or in case of an error
[NACK|AL interrupt]
Signed-off-by: Moiz Sonasath <m-sonasath@ti.com>
Signed-off-by: Vikram Pandita <vikram.pandita@ti.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
I2C status ack for [RX]RDR and [RX]RDY could
cause race conditions of clearing the event
twice and a violation of the programing
sequence as defined in TRM This patch fixes
the same.
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Moiz Sonasath <m-sonasath@ti.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Without the check, the config space may be filled with zeros. Though
the driver should try to avoid call restoring before saving, but the
pci layer also should check this.
Also removes the existing check in pci_restore_standard_config, since
it's superfluous with the new check in restore_state.
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Alek Du <alek.du@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
There are many variants of Toshiba laptops with ALC268 codec, and
it seems that a few of them don't work with model=toshiba preset
since they have the secondary ALC268 codec just for HDMI output.
This is a regression due to the previous clean-up work to merge all
Toshiba quirk entries into a single check.
This patch adds the identification of such laptops to apply the
standard BIOS-probing method. Unfortunately, Toshiba laptops have
all the same PCI SSID, so we need to check the codec SSID to identify
each device.
Tested-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2:
nilfs2: fix oopses with doubly mounted snapshots
nilfs2: missing a read lock for segment writer in nilfs_attach_checkpoint()
Fix some issues with the AFS documentation, found when testing AFS on ppc64:
- Update AFS features: reading/writing, local caching
- Typo in kafs sysfs debug file
- Use modprobe instead of insmod in example
- Update IPs for grand.central.org
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6:
drm/kms: teardown crtc correctly when fb is destroyed.
drm/kms/radeon: cleanup combios TV table like DDX.
drm/radeon/kms: memset the allocated framebuffer before using it.
drm/radeon/kms: although LVDS might be possible on crtc 1 don't do it.
drm/radeon/kms: implement bo busy check + current domain
drm/radeon/kms: cut down indirects in register accesses.
drm/radeon/kms: Fix up vertical blank interrupt support.
drm/radeon/kms: add rv530 R300_SU_REG_DEST + reloc for ZPASS_ADDR
drm/edid: fixup detailed timings like the X server.
drm/radeon/kms: Add specific rs690 authorized register table
* 'next' of git://git.monstr.eu/linux-2.6-microblaze:
microblaze: Update Microblaze defconfigs
microblaze: Use klimit instead of _end for memory init
microblaze: Enable ppoll syscall
microblaze: Sane handling of missing timer/intc in device tree
microblaze: use the generic ack_bad_irq implementation
The BIOS pin configs are in fact correct and shall not be overwritten.
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
HP Compaq 6530s and 6531s internal speaker is silence or becomes silence
within 1 minute after fresh boot. It is found that pin 0x1c must be set to
PIN_OUT mode to make the speaker work. This is weird - line-in pin 0x1c and
speaker pin 0x16 seem to be unrelated.
The codec differences before/after patch are:
@@ Node 0x17 [Pin Complex] wcaps 0x40020b:
Pin Default 0x41a6e130: [N/A] Mic at Ext Rear
Conn = Digital, Color = White
DefAssociation = 0x3, Sequence = 0x0
Misc = NO_PRESENCE
- Pin-ctls: 0x24: IN
+ Pin-ctls: 0x40: OUT
@@ Node 0x1c [Pin Complex] wcaps 0x40018d:
Pin Default 0x41813021: [N/A] Line In at Ext Rear
Conn = 1/8, Color = Blue
DefAssociation = 0x2, Sequence = 0x1
- Pin-ctls: 0x24: IN VREF_80
+ Pin-ctls: 0x40: OUT VREF_HIZ
Unsolicited: tag=00, enabled=0
Connection: 1
0x24
Tests show that it won't impact (external) Mic recording.
Reported-by: "Lin, Ming M" <ming.m.lin@intel.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
If userspace destroys a framebuffer that is in use on a crtc,
don't just null it out, tear down the crtc properly so the
hw gets turned off.
Signed-off-by: Dave Airlie <airlied@redhat.com>
The fallback case wasn't getting executed properly if there
was no TV table, which my T42 M7 hasn't got.
Signed-off-by: Dave Airlie <airlied@redhat.com>
LVDS always requests RMX_FULL, we need to fix it so that doesn't happen
before we can enable LVDS on crtc 1.
Signed-off-by: Dave Airlie <airlied@redhat.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6:
security: Fix prompt for LSM_MMAP_MIN_ADDR
security: Make LSM_MMAP_MIN_ADDR default match its help text.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
percpu: use the right flag for get_vm_area()
percpu, sparc64: fix sparse possible cpu map handling
init: set nr_cpu_ids before setup_per_cpu_areas()
If node_load[] is cleared everytime build_zonelists() is
called,node_load[] will have no help to find the next node that should
appear in the given node's fallback list.
Because of the bug, zonelist's node_order is not calculated as expected.
This bug affects on big machine, which has asynmetric node distance.
[synmetric NUMA's node distance]
0 1 2
0 10 12 12
1 12 10 12
2 12 12 10
[asynmetric NUMA's node distance]
0 1 2
0 10 12 20
1 12 10 14
2 20 14 10
This (my bug) is very old but no one has reported this for a long time.
Maybe because the number of asynmetric NUMA is very small and they use
cpuset for customizing node memory allocation fallback.
[akpm@linux-foundation.org: fix CONFIG_NUMA=n build]
Signed-off-by: Bo Liu <bo-liu@hotmail.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
According to the POSIX (1003.1-2008), the file descriptor shall have been
opened with read permission, regardless of the protection options specified to
mmap(). The ltp test cases mmap06/07 need this.
Signed-off-by: Graff Yang <graff.yang@gmail.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since the changes to the bitbang driver, there is the possibility we will
be called with either the speed_hz or bpw values zero. We take these to
mean that the default values (8 bits per word, or maximum bus speed).
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently the clock rate calculation may round as pleased, which means
that it is possible that we will round down and end up with a faster clock
rate than intended.
Change the calculation to use DIV_ROUND_UP() to ensure that we end up with
a clock rate either the same as or lower than the user requested one.
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are a number of individual MMC drivers listed in MAINTAINERS. I
didn't modify those records. Perhaps I should have.
Cc: <linux-mmc@vger.kernel.org>
Cc: Manuel Lauss <manuel.lauss@gmail.com>
Cc: Nicolas Pitre <nico@cam.org>
Cc: Pierre Ossman <drzeus@drzeus.cx>
Cc: Pavel Pisa <ppisa@pikron.com>
Cc: Jarkko Lavinen <jarkko.lavinen@nokia.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Sascha Sommer <saschasommer@freenet.de>
Cc: Ian Molton <ian@mnementh.co.uk>
Cc: Joseph Chan <JosephChan@via.com.tw>
Cc: Harald Welte <HaraldWelte@viatech.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The commit 2ff05b2b (oom: move oom_adj value) moveed the oom_adj value to
the mm_struct. It was a very good first step for sanitize OOM.
However Paul Menage reported the commit makes regression to his job
scheduler. Current OOM logic can kill OOM_DISABLED process.
Why? His program has the code of similar to the following.
...
set_oom_adj(OOM_DISABLE); /* The job scheduler never killed by oom */
...
if (vfork() == 0) {
set_oom_adj(0); /* Invoked child can be killed */
execve("foo-bar-cmd");
}
....
vfork() parent and child are shared the same mm_struct. then above
set_oom_adj(0) doesn't only change oom_adj for vfork() child, it's also
change oom_adj for vfork() parent. Then, vfork() parent (job scheduler)
lost OOM immune and it was killed.
Actually, fork-setting-exec idiom is very frequently used in userland program.
We must not break this assumption.
Then, this patch revert commit 2ff05b2b and related commit.
Reverted commit list
---------------------
- commit 2ff05b2b4e (oom: move oom_adj value from task_struct to mm_struct)
- commit 4d8b9135c3 (oom: avoid unnecessary mm locking and scanning for OOM_DISABLE)
- commit 8123681022 (oom: only oom kill exiting tasks with attached memory)
- commit 933b787b57 (mm: copy over oom_adj value at fork time)
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
get_sb_pseudo sets s_maxbytes to ~0ULL which becomes negative when cast
to a signed value. Fix it to use MAX_LFS_FILESIZE which casts properly
to a positive signed value.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Steve French <smfrench@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Robert Love <rlove@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix prompt for LSM_MMAP_MIN_ADDR.
(Verbs are cool!)
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Commit 788084aba2 added the LSM_MMAP_MIN_ADDR
option, whose help text states "For most ia64, ppc64 and x86 users with lots
of address space a value of 65536 is reasonable and should cause no problems."
Which implies that it's default setting was typoed.
Signed-off-by: Dave Jones <davej@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (60 commits)
net: restore gnet_stats_basic to previous definition
NETROM: Fix use of static buffer
e1000e: fix use of pci_enable_pcie_error_reporting
e1000e: WoL does not work on 82577/82578 with manageability enabled
cnic: Fix locking in init/exit calls.
cnic: Fix locking in start/stop calls.
bnx2: Use mutex on slow path cnic calls.
cnic: Refine registration with bnx2.
cnic: Fix symbol_put_addr() panic on ia64.
gre: Fix MTU calculation for bound GRE tunnels
pegasus: Add new device ID.
drivers/net: fixed drivers that support netpoll use ndo_start_xmit()
via-velocity: Fix test of mii_status bit VELOCITY_DUPLEX_FULL
rt2x00: fix memory corruption in rf cache, add a sanity check
ixgbe: Fix receive on real device when VLANs are configured
ixgbe: Do not return 0 in ixgbe_fcoe_ddp() upon FCP_RSP in DDP completion
netxen: free napi resources during detach
netxen: remove netxen workqueue
ixgbe: fix issues setting rx-usecs with legacy interrupts
can: fix oops caused by wrong rtnl newlink usage
...
will fix kernel oopses like the following:
# mount -t nilfs2 -r -o cp=20 /dev/sdb1 /test1
# mount -t nilfs2 -r -o cp=20 /dev/sdb1 /test2
# umount /test1
# umount /test2
BUG: sleeping function called from invalid context at arch/x86/mm/fault.c:1069
in_atomic(): 0, irqs_disabled(): 1, pid: 3886, name: umount.nilfs2
1 lock held by umount.nilfs2/3886:
#0: (&type->s_umount_key#31){+.+...}, at: [<c10b398a>] deactivate_super+0x52/0x6c
irq event stamp: 1219
hardirqs last enabled at (1219): [<c135c774>] __mutex_unlock_slowpath+0xf8/0x119
hardirqs last disabled at (1218): [<c135c6d5>] __mutex_unlock_slowpath+0x59/0x119
softirqs last enabled at (1214): [<c1033316>] __do_softirq+0x1a5/0x1ad
softirqs last disabled at (1205): [<c1033354>] do_softirq+0x36/0x5a
Pid: 3886, comm: umount.nilfs2 Not tainted 2.6.31-rc6 #55
Call Trace:
[<c1023549>] __might_sleep+0x107/0x10e
[<c13603c0>] do_page_fault+0x246/0x397
[<c136017a>] ? do_page_fault+0x0/0x397
[<c135e753>] error_code+0x6b/0x70
[<c136017a>] ? do_page_fault+0x0/0x397
[<c104f805>] ? __lock_acquire+0x91/0x12fd
[<c1050a62>] ? __lock_acquire+0x12ee/0x12fd
[<c1050a62>] ? __lock_acquire+0x12ee/0x12fd
[<c1050b2b>] lock_acquire+0xba/0xdd
[<d0d17d3f>] ? nilfs_detach_segment_constructor+0x2f/0x2fa [nilfs2]
[<c135d4fe>] down_write+0x2a/0x46
[<d0d17d3f>] ? nilfs_detach_segment_constructor+0x2f/0x2fa [nilfs2]
[<d0d17d3f>] nilfs_detach_segment_constructor+0x2f/0x2fa [nilfs2]
[<c104ea2c>] ? mark_held_locks+0x43/0x5b
[<c104ecb1>] ? trace_hardirqs_on_caller+0x10b/0x133
[<c104ece4>] ? trace_hardirqs_on+0xb/0xd
[<d0d09ac1>] nilfs_put_super+0x2f/0xca [nilfs2]
[<c10b3352>] generic_shutdown_super+0x49/0xb8
[<c10b33de>] kill_block_super+0x1d/0x31
[<c10e6599>] ? vfs_quota_off+0x0/0x12
[<c10b398f>] deactivate_super+0x57/0x6c
[<c10c4bc3>] mntput_no_expire+0x8c/0xb4
[<c10c5094>] sys_umount+0x27f/0x2a4
[<c10c50c6>] sys_oldumount+0xd/0xf
[<c10031a4>] sysenter_do_call+0x12/0x38
...
This turns out to be a bug brought by an -rc1 patch ("nilfs2: simplify
remaining sget() use").
In the patch, a new "put resource" function, nilfs_put_sbinfo()
was introduced to delay freeing nilfs_sb_info struct.
But the nilfs_put_sbinfo() mistakenly used atomic_dec_and_test()
function to check the reference count, and it caused the nilfs_sb_info
was freed when user mounted a snapshot twice.
This bug also suggests there was unseen memory leak in usual mount
/umount operations for nilfs.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
