Shift current_cred() from __f_setown() to f_modown(). This reduces
the number of arguments and saves 48 bytes from fs/fcntl.o.
[ Note: this doesn't clear euid/uid when pid is set to NULL. But if
f_owner.pid == NULL we never use f_owner.uid/euid. Otherwise we'd
have a bug anyway: we must not send signals if pid was reset to NULL. ]
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6: (64 commits)
debugfs: use specified mode to possibly mark files read/write only
debugfs: Fix terminology inconsistency of dir name to mount debugfs filesystem.
xen: remove driver_data direct access of struct device from more drivers
usb: gadget: at91_udc: remove driver_data direct access of struct device
uml: remove driver_data direct access of struct device
block/ps3: remove driver_data direct access of struct device
s390: remove driver_data direct access of struct device
parport: remove driver_data direct access of struct device
parisc: remove driver_data direct access of struct device
of_serial: remove driver_data direct access of struct device
mips: remove driver_data direct access of struct device
ipmi: remove driver_data direct access of struct device
infiniband: ehca: remove driver_data direct access of struct device
ibmvscsi: gadget: at91_udc: remove driver_data direct access of struct device
hvcs: remove driver_data direct access of struct device
xen block: remove driver_data direct access of struct device
thermal: remove driver_data direct access of struct device
scsi: remove driver_data direct access of struct device
pcmcia: remove driver_data direct access of struct device
PCIE: remove driver_data direct access of struct device
...
Manually fix up trivial conflicts due to different direct driver_data
direct access fixups in drivers/block/{ps3disk.c,ps3vram.c}
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2:
ocfs2/net: Use wait_event() in o2net_send_message_vec()
ocfs2: Adjust rightmost path in ocfs2_add_branch.
ocfs2: fdatasync should skip unimportant metadata writeout
ocfs2: Remove redundant gotos in ocfs2_mount_volume()
ocfs2: Add statistics for the checksum and ecc operations.
ocfs2 patch to track delayed orphan scan timer statistics
ocfs2: timer to queue scan of all orphan slots
ocfs2: Correct ordering of ip_alloc_sem and localloc locks for directories
ocfs2: Fix possible deadlock in quota recovery
ocfs2: Fix possible deadlock with quotas in ocfs2_setattr()
ocfs2: Fix lock inversion in ocfs2_local_read_info()
ocfs2: Fix possible deadlock in ocfs2_global_read_dquot()
ocfs2: update comments in masklog.h
ocfs2: Don't printk the error when listing too many xattrs.
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
block: remove some includings of blktrace_api.h
mg_disk: seperate mg_disk.h again
block: Introduce helper to reset queue limits to default values
cfq: remove extraneous '\n' in blktrace output
ubifs: register backing_dev_info
btrfs: properly register fs backing device
block: don't overwrite bdi->state after bdi_init() has been run
cfq: cleanup for last_end_request in cfq_data
Commit fec1878fe9 caused a regression in
which contiguous blocks being allocated to the end of an extent were
getting a new extent created. This typically results in files entirely
made up of 1-block extents even though the blocks are contiguous on
disk.
Apparently grub doesn't handle a jfs file being fragmented into too many
extents, since it refuses to boot a kernel from jfs that was created by
the 2.6.30 kernel.
Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Reported-by: Alex <alevkovich@tut.by>
When porting blktrace to tracepoints, we changed to trace/block.h
for trace prober declarations.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
btrfs assigns this bdi to all inodes on that file system, so make
sure it's registered. This isn't really important now, but will be
when we put dirty inodes there. Even now, we miss the stats when the
bdi isn't visible.
Also fixes failure to check bdi_init() return value, and bad inherit of
->capabilities flags from the default bdi.
Acked-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This patch (as1239) updates the kernel's treatment of Unicode. The
character-set conversion routines are well behind the current state of
the Unicode specification: They don't recognize the existence of code
points beyond plane 0 or of surrogate pairs in the UTF-16 encoding.
The old wchar_t 16-bit type is retained because it's still used in
lots of places. This shouldn't cause any new problems; if a
conversion now results in an invalid 16-bit code then before it must
have yielded an undefined code.
Difficult-to-read names like "utf_mbstowcs" are replaced with more
transparent names like "utf8s_to_utf16s" and the ordering of the
parameters is rationalized (buffer lengths come immediate after the
pointers they refer to, and the inputs precede the outputs).
Fortunately the low-level conversion routines are used in only a few
places; the interfaces to the higher-level uni2char and char2uni
methods have been left unchanged.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
utf8_wcstombs forgot to include one-byte UTF-8 characters when
calculating the output buffer size, i.e., theoretically, it was possible
to overflow the output buffer with an input string that contains enough
ASCII characters.
In practice, this was no problem because the only user so far (VFAT)
always uses a big enough output buffer.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When utf8_wcstombs encounters a character that cannot be encoded, we
must not decrease the remaining output buffer size because nothing has
been written to the output buffer.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
In many SoC implementations there are hardware registers can be read or
write only. This extends the debugfs to enforce the file permissions for
these types of registers by providing a set of fops which are read or
write only. This assumes that the kernel developer knows more about the
hardware than the user (even root users) -- which is normally true.
Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Fix an error in debugfs_create_blob's docbook description
It cannot actually be used to write a binary blob.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
debugfs: dont stop on first failed recursive delete
While running a while loop of removing a module that removes a debugfs
directory with debugfs_remove_recursive, and at the same time doing a
while loop of cat of a file in that directory, I would hit a point where
somehow the cat of the file caused the remove to fail.
The result is that other files did not get removed when the module
was removed. I simple read of one of those file can oops the kernel
because the operations to the file no longer exist (removed by module).
The funny thing is that the file being cat'ed was removed. It was
the siblings that were not. I see in the code to debugfs_remove_recursive
there's a test that checks if the child fails to bail out of the loop
to prevent an infinite loop.
What this patch does is to still try any siblings in that directory.
If all the siblings fail, or there are no more siblings, then we exit
the loop.
This fixes the above symptom, but...
This is no full proof. It makes the debugfs_remove_recursive a bit more
robust, but it does not explain why the one file failed. There may
be some kind of delay deletion that makes the debugfs think it did
not succeed. So this patch is more of a fix for the symptom but not
the disease.
This patch still makes the debugfs_remove_recursive more robust and
until I can find out why the bug exists, this patch will keep
the kernel from oopsing in most cases. Even after the cause is found
I think this change can stand on its own and should be kept.
[ Impact: prevent kernel oops on module unload and reading debugfs files ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
There is the possiblity of a memory leak if a page is allocated and if
sysfs_getlink() fails in the sysfs_follow_link.
Signed-off-by: Armin Kuster <akuster@mvista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
commit_fs_roots skips updating root items for fs trees that aren't modified.
This is unsafe now that relocation code modifies root item's last_snapshot
field without modifying corresponding fs tree.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Replace wait_event_interruptible() with wait_event() in o2net_send_message_vec().
This is because this function is called by the dlm that expects signals to be
blocked.
Fixes oss bugzilla#1126
http://oss.oracle.com/bugzilla/show_bug.cgi?id=1126
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
In ocfs2_add_branch, we use the rightmost rec of the leaf extent block
to generate the e_cpos for the newly added branch. In the most case, it
is OK but if the parent extent block's rightmost rec covers more clusters
than the leaf does, it will cause kernel panic if we insert some clusters
in it. The message is something like:
(7445,1):ocfs2_insert_at_leaf:3775 ERROR: bug expression:
le16_to_cpu(el->l_next_free_rec) >= le16_to_cpu(el->l_count)
(7445,1):ocfs2_insert_at_leaf:3775 ERROR: inode 66053, depth 0, count 28,
next free 28, rec.cpos 270, rec.clusters 1, insert.cpos 275, insert.clusters 1
[<fa7ad565>] ? ocfs2_do_insert_extent+0xb58/0xda0 [ocfs2]
[<fa7b08f2>] ? ocfs2_insert_extent+0x5bd/0x6ba [ocfs2]
[<fa7b1b8b>] ? ocfs2_add_clusters_in_btree+0x37f/0x564 [ocfs2]
...
The panic can be easily reproduced by the following small test case
(with bs=512, cs=4K, and I remove all the error handling so that it looks
clear enough for reading).
int main(int argc, char **argv)
{
int fd, i;
char buf[5] = "test";
fd = open(argv[1], O_RDWR|O_CREAT);
for (i = 0; i < 30; i++) {
lseek(fd, 40960 * i, SEEK_SET);
write(fd, buf, 5);
}
ftruncate(fd, 1146880);
lseek(fd, 1126400, SEEK_SET);
write(fd, buf, 5);
close(fd);
return 0;
}
The reason of the panic is that:
the 30 writes and the ftruncate makes the file's extent list looks like:
Tree Depth: 1 Count: 19 Next Free Rec: 1
## Offset Clusters Block#
0 0 280 86183
SubAlloc Bit: 7 SubAlloc Slot: 0
Blknum: 86183 Next Leaf: 0
CRC32: 00000000 ECC: 0000
Tree Depth: 0 Count: 28 Next Free Rec: 28
## Offset Clusters Block# Flags
0 0 1 143368 0x0
1 10 1 143376 0x0
...
26 260 1 143576 0x0
27 270 1 143584 0x0
Now another write at 1126400(275 cluster) whiich will write at the gap
between 271 and 280 will trigger ocfs2_add_branch, but the result after
the function looks like:
Tree Depth: 1 Count: 19 Next Free Rec: 2
## Offset Clusters Block#
0 0 280 86183
1 271 0 143592
So the extent record is intersected and make the following operation bug out.
This patch just try to remove the gap before we add the new branch, so that
the root(branch) rightmost rec will cover the same right position. So in the
above case, before adding branch the tree will be changed to
Tree Depth: 1 Count: 19 Next Free Rec: 1
## Offset Clusters Block#
0 0 271 86183
SubAlloc Bit: 7 SubAlloc Slot: 0
Blknum: 86183 Next Leaf: 0
CRC32: 00000000 ECC: 0000
Tree Depth: 0 Count: 28 Next Free Rec: 28
## Offset Clusters Block# Flags
0 0 1 143368 0x0
1 10 1 143376 0x0
...
26 260 1 143576 0x0
27 270 1 143584 0x0
And after branch add, the tree looks like
Tree Depth: 1 Count: 19 Next Free Rec: 2
## Offset Clusters Block#
0 0 271 86183
1 271 0 143592
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Acked-by: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2: (22 commits)
nilfs2: support contiguous lookup of blocks
nilfs2: add sync_page method to page caches of meta data
nilfs2: use device's backing_dev_info for btree node caches
nilfs2: return EBUSY against delete request on snapshot
nilfs2: modify list of unsupported features in caveats
nilfs2: enable sync_page method
nilfs2: set bio unplug flag for the last bio in segment
nilfs2: allow future expansion of metadata read out via get info ioctl
NILFS2: Pagecache usage optimization on NILFS2
nilfs2: remove nilfs_btree_operations from btree mapping
nilfs2: remove nilfs_direct_operations from direct mapping
nilfs2: remove bmap pointer operations
nilfs2: remove useless b_low and b_high fields from nilfs_bmap struct
nilfs2: remove pointless NULL check of bpop_commit_alloc_ptr function
nilfs2: move get block functions in bmap.c into btree codes
nilfs2: remove nilfs_bmap_delete_block
nilfs2: remove nilfs_bmap_put_block
nilfs2: remove header file for segment list operations
nilfs2: eliminate removal list of segments
nilfs2: add sufile function that can modify multiple segment usages
...
On systems where CONFIG_SHMEM is disabled, mounting tmpfs filesystems can
fail when tmpfs options are used. This is because tmpfs creates a small
wrapper around ramfs which rejects unknown options, and ramfs itself only
supports a tiny subset of what tmpfs supports. This makes it pretty hard
to use the same userspace systems across different configuration systems.
As such, ramfs should ignore the tmpfs options when tmpfs is merely a
wrapper around ramfs.
This used to work before commit c3b1b1cbf0 as previously, ramfs would
ignore all options. But now, we get:
ramfs: bad mount option: size=10M
mount: mounting mdev on /dev failed: Invalid argument
Another option might be to restore the previous behavior, where ramfs
simply ignored all unknown mount options ... which is what Hugh prefers.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Matt Mackall <mpm@selenic.com>
Acked-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Identation got messed up when merging the current_umask changes with
the generic ACL support.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Felix Blyakher <felixb@sgi.com>
Signed-off-by: Felix Blyakher <felixb@sgi.com>
Fix warnings about unitialized dquot variables by making sure
xfs_qm_vop_dqalloc touches it even when quotas are disabled.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Felix Blyakher <felixb@sgi.com>
Signed-off-by: Felix Blyakher <felixb@sgi.com>
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/configfs:
configfs: Rework configfs_depend_item() locking and make lockdep happy
configfs: Silence lockdep on mkdir() and rmdir()
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/dlm:
dlm: use more NOFS allocation
dlm: connect to nodes earlier
dlm: fix use count with multiple joins
dlm: Make name input parameter of {,dlm_}new_lockspace() const
* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (154 commits)
[SCSI] osd: Remove out-of-tree left overs
[SCSI] libosd: Use REQ_QUIET requests.
[SCSI] osduld: use filp_open() when looking up an osd-device
[SCSI] libosd: Define an osd_dev wrapper to retrieve the request_queue
[SCSI] libosd: osd_req_{read,write} takes a length parameter
[SCSI] libosd: Let _osd_req_finalize_data_integrity receive number of out_bytes
[SCSI] libosd: osd_req_{read,write}_kern new API
[SCSI] libosd: Better printout of OSD target system information
[SCSI] libosd: OSD2r05: Attribute definitions
[SCSI] libosd: OSD2r05: Additional command enums
[SCSI] mpt fusion: fix up doc book comments
[SCSI] mpt fusion: Added support for Broadcast primitives Event handling
[SCSI] mpt fusion: Queue full event handling
[SCSI] mpt fusion: RAID device handling and Dual port Raid support is added
[SCSI] mpt fusion: Put IOC into ready state if it not already in ready state
[SCSI] mpt fusion: Code Cleanup patch
[SCSI] mpt fusion: Rescan SAS topology added
[SCSI] mpt fusion: SAS topology scan changes, expander events
[SCSI] mpt fusion: Firmware event implementation using seperate WorkQueue
[SCSI] mpt fusion: rewrite of ioctl_cmds internal generated function
...
* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-lguest: (31 commits)
lguest: add support for indirect ring entries
lguest: suppress notifications in example Launcher
lguest: try to batch interrupts on network receive
lguest: avoid sending interrupts to Guest when no activity occurs.
lguest: implement deferred interrupts in example Launcher
lguest: remove obsolete LHREQ_BREAK call
lguest: have example Launcher service all devices in separate threads
lguest: use eventfds for device notification
eventfd: export eventfd_signal and eventfd_fget for lguest
lguest: allow any process to send interrupts
lguest: PAE fixes
lguest: PAE support
lguest: Add support for kvm_hypercall4()
lguest: replace hypercall name LHCALL_SET_PMD with LHCALL_SET_PGD
lguest: use native_set_* macros, which properly handle 64-bit entries when PAE is activated
lguest: map switcher with executable page table entries
lguest: fix writev returning short on console output
lguest: clean up length-used value in example launcher
lguest: Segment selectors are 16-bit long. Fix lg_cpu.ss1 definition.
lguest: beyond ARRAY_SIZE of cpu->arch.gdt
...
* 'cuse' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
CUSE: implement CUSE - Character device in Userspace
fuse: export symbols to be used by CUSE
fuse: update fuse_conn_init() and separate out fuse_conn_kill()
fuse: don't use inode in fuse_file_poll
fuse: don't use inode in fuse_do_ioctl() helper
fuse: don't use inode in fuse_sync_release()
fuse: create fuse_do_open() helper for CUSE
fuse: clean up args in fuse_finish_open() and fuse_release_fill()
fuse: don't use inode in helpers called by fuse_direct_io()
fuse: add members to struct fuse_file
fuse: prepare fuse_direct_io() for CUSE
fuse: clean up fuse_write_fill()
fuse: use struct path in release structure
fuse: misc cleanups
* 'for-2.6.31' of git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6: (29 commits)
ide: re-implement ide_pci_init_one() on top of ide_pci_init_two()
ide: unexport ide_find_dma_mode()
ide: fix PowerMac bootup oops
ide: skip probe if there are no devices on the port (v2)
sl82c105: add printk() logging facility
ide-tape: fix proc warning
ide: add IDE_DFLAG_NIEN_QUIRK device flag
ide: respect quirk_drives[] list on all controllers
hpt366: enable all quirks for devices on quirk_drives[] list
hpt366: sync quirk_drives[] list with pdc202xx_{new,old}.c
ide: remove superfluous SELECT_MASK() call from do_rw_taskfile()
ide: remove superfluous SELECT_MASK() call from ide_driveid_update()
icside: remove superfluous ->maskproc method
ide-tape: fix IDE_AFLAG_* atomic accesses
ide-tape: change IDE_AFLAG_IGNORE_DSC non-atomically
pdc202xx_old: kill resetproc() method
pdc202xx_old: don't call pdc202xx_reset() on IRQ timeout
pdc202xx_old: use ide_dma_test_irq()
ide: preserve Host Protected Area by default (v2)
ide-gd: implement block device ->set_capacity method (v2)
...
The advertised flag for not updating the time was wrong.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Regression from commit 28e211700a.
Need to free temporary buffer allocated in xfs_getbmap().
Signed-off-by: Felix Blyakher <felixb@sgi.com>
Signed-off-by: Hedi Berriche <hedi@sgi.com>
Reported-by: Justin Piszcz <jpiszcz@lucidpixels.com>
Reviewed-by: Eric Sandeen <sandeen@sandeen.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Conflicts:
drivers/message/fusion/mptsas.c
fixed up conflict between req->data_len accessors and mptsas driver updates.
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
lguest wants to attach eventfds to guest notifications, and lguest is
usually a module.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
To: Davide Libenzi <davidel@xmailserver.org>
This patch adds the ability to trace various aspects of the GFS2
filesystem. The trace points are divided into three groups,
glocks, logging and bmap. These points have been chosen because
they allow inspection of the major internal functions of GFS2
and they are also generic enough that they are unlikely to need
any major changes as the filesystem evolves.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This will remove every bd_mount_sem use in nilfs.
The intended exclusion control was replaced by the previous patch
("nilfs2: correct exclusion control in nilfs_remount function") for
nilfs_remount(), and this patch will replace remains with a new mutex
that this inserts in nilfs object.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
nilfs_remount() changes mount state of a superblock instance. Even
though nilfs accesses other superblock instances during mount or
remount, the mount state was not properly protected in
nilfs_remount().
Moreover, nilfs_remount() has a lock order reversal problem;
nilfs_get_sb() holds:
1. bdev->bd_mount_sem
2. sb->s_umount (sget acquires)
and nilfs_remount() holds:
1. sb->s_umount (locked by the caller in vfs)
2. bdev->bd_mount_sem
To avoid these problems, this patch divides a semaphore protecting
super block instances from nilfs->ns_sem, and applies it to the mount
state protection in nilfs_remount().
With this change, bd_mount_sem use is removed from nilfs_remount() and
the lock order reversal will be resolved. And the new rw-semaphore,
nilfs->ns_super_sem will properly protect the mount state except the
modification from nilfs_error function.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This simplifies the test function passed on the remaining sget()
callsite in nilfs.
Instead of checking mount type (i.e. ro-mount/rw-mount/snapshot mount)
in the test function passed to sget(), this patch first looks up the
nilfs_sb_info struct which the given mount type matches, and then
acquires the super block instance holding the nilfs_sb_info.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This stops using sget() for checking if an r/w-mount or an r/o-mount
exists on the device. This elimination uses a back pointer to the
current mount added to nilfs object.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This will change the way to obtain nilfs object in nilfs_get_sb()
function.
Previously, a preliminary sget() call was performed, and the nilfs
object was acquired from a super block instance found by the sget()
call.
This patch, instead, instroduces a new dedicated function
find_or_create_nilfs(); as the name implies, the function finds an
existent nilfs object from a global list or creates a new one if no
object is found on the device.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>