* 'next-devicetree' of git://git.secretlab.ca/git/linux-2.6: (41 commits)
of: remove undefined request_OF_resource & release_OF_resource
of/sparc: Remove sparc-local declaration of allnodes and devtree_lock
of: move definition of of_chosen into common code.
of: remove unused extern reference to devtree_lock
of: put default string compare and #a/s-cell values into common header
of/flattree: Don't assume HAVE_LMB
of: protect linux/of.h with CONFIG_OF
proc_devtree: fix THIS_MODULE without module.h
of: Remove old and misplaced function declarations
of/flattree: Make the kernel accept ePAPR style phandle information
of/flattree: endian-convert members of boot_param_header
of: assume big-endian properties, adding conversions where necessary
of: use __be32 for cell value accessors
of/flattree: use OF_ROOT_NODE_{SIZE,ADDR}_CELLS DEFAULT for fdt parsing
of/flattree: use callback to setup initrd from /chosen
proc_devtree: include linux/of.h
of: make set_node_proc_entry private to proc_devtree.c
of: include linux/proc_fs.h
of/flattree: merge early_init_dt_scan_memory() common code
of: add 'of_' prefix to machine_is_compatible()
...
803bf5ec25 ("fs/exec.c: restrict initial
stack space expansion to rlimit") attempts to limit the initial stack to
20*PAGE_SIZE. Unfortunately, in attempting ensure the stack is not
reduced in size, we ended up not changing the stack at all.
This size reduction check is not necessary as the expand_stack call does
this already.
This caused a regression in UML resulting in most guest processes being
killed.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jouni Malinen <j@w1.fi>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
cachefiles_delete_object() can race with rename. It gets the parent directory
of the object it's asked to delete, then locks it - but rename may have changed
the object's parent between the get and the completion of the lock.
However, if such a circumstance is detected, we abandon our attempt to delete
the object - since it's no longer in the index key path, it won't be seen
again by lookups of that key. The assumption is that cachefilesd may have
culled it by renaming it to the graveyard for later destruction.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
commit 1e41568d73 ("Take ima_path_check()
in nfsd past dentry_open() in nfsd_open()") moved this code back to its
original location but missed the "else".
Signed-off-by: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Make sure that automount "symlinks" are followed regardless of LOOKUP_FOLLOW;
it should have no effect on them.
Cc: stable@kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
There is currently a bug in sysfs_sd_setattr inherited from
sysfs_setattr in 2.6.32 where the first time we set the attributes
on a sysfs file we allocate backing store but do not set the
backing store attributes. Resulting in overly restrictive
permissions on sysfs files.
The fix is to simply modify the code so that it always executes
when we update the sysfs attributes, as we did in 2.6.31 and earlier.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Tested-by: Jean Delvare <khali@linux-fr.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The cached read and write paths initialize fattr->time_start in their
setup procedures. The value of fattr->time_start is propagated to
read_cache_jiffies by nfs_update_inode(). Subsequent calls to
nfs_attribute_timeout() will then use a good time stamp when
computing the attribute cache timeout, and squelch unneeded GETATTR
calls.
Since the direct I/O paths erroneously leave the inode's
fattr->time_start field set to zero, read_cache_jiffies for that inode
is set to zero after any direct read or write operation. This
triggers an otw GETATTR or ACCESS call to update the file's attribute
and access caches properly, even when the NFS READ or WRITE replies
have usable post-op attributes.
Make sure the direct read and write setup code performs the same fattr
initialization as the cached I/O paths to prevent unnecessary GETATTR
calls.
This was likely introduced by commit 0e574af1 in 2.6.15, which appears
to add new nfs_fattr_init() call sites in the cached read and write
paths, but not in the equivalent places in fs/nfs/direct.c. A
subsequent commit in the same series, 33801147, introduces the
fattr->time_start field.
Interestingly, the direct write reschedule path already has a call to
nfs_fattr_init() in the right place.
Reported-by: Quentin Barnes <qbarnes@yahoo-inc.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@kernel.org
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When we wait for an inode through reiserfs_iget(), we hold
the reiserfs lock. And waiting for an inode may imply waiting
for its writeback. But the inode writeback path may also require
the reiserfs lock, which leads to a deadlock.
We just need to release the reiserfs lock from reiserfs_iget()
to fix this.
Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Tested-by: Christian Kujau <lists@nerdbynature.de>
Cc: Chris Mason <chris.mason@oracle.com>
Commit e22f628395 introduced a build
breakage for ARM devtree work: the THIS_MODULE macro was added, but we
don't have module.h
This change adds the necessary #include to get THIS_MODULE defined.
While we could just replace it with NULL (PROC_FS is a bool, not a
tristate), using THIS_MODULE will prevent unexpected breakage if we
ever do compile this as a module.
Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Michal Simek <monstr@monstr.eu>
My test do: fallocate a big file and do write. The file is 512M, but
after file write is done btrfs-debug-tree shows:
item 6 key (257 EXTENT_DATA 0) itemoff 3516 itemsize 53
extent data disk byte 1103101952 nr 536870912
extent data offset 0 nr 399634432 ram 536870912
extent compression 0
Looks like a regression introducted by
6c7d54ac87, where we set wrong slot.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Acked-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This patch solves a corner case during allocation which occurs if both
metadata (indirect) and data blocks are required but there is an
obstacle in the filesystem (e.g. a resource group header or another
allocated block) such that when the allocation is requested only
enough blocks for the metadata are returned.
By changing the exit condition of this loop, we ensure that a
minimum of one data block will always be returned.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
We need this one-liner to signal the mount helper of the 'insufficient journals' condition.
Signed-off-by: Abhijith Das <adas@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
* 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6:
NFS: Fix the mapping of the NFSERR_SERVERFAULT error
NFS: Remove a redundant check for PageFsCache in nfs_migrate_page()
NFS: Fix a bug in nfs_fscache_release_page()
* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6:
[SCSI] qla2xxx: Obtain proper host structure during response-queue processing.
[SCSI] compat_ioct: fix bsg SG_IO
[SCSI] qla2xxx: make msix interrupt handler safe for irq
[SCSI] zfcp: Report FC BSG errors in correct field
[SCSI] mptfusion : mptscsih_abort return value should be SUCCESS instead of value 0.
When reserving stack space for a new process, make sure we're not
attempting to expand the stack by more than rlimit allows.
This fixes a bug caused by b6a2fea393 ("mm:
variable length argument support") and unmasked by
fc63cf2370 ("exec: setup_arg_pages() fails
to return errors").
This bug means that when limiting the stack to less the 20*PAGE_SIZE (eg.
80K on 4K pages or 'ulimit -s 79') all processes will be killed before
they start. This is particularly bad with 64K pages, where a ulimit below
1280K will kill every process.
To test, do:
'ulimit -s 15; ls'
before and after the patch is applied. Before it's applied, 'ls' should
be killed. After the patch is applied, 'ls' should no longer be killed.
A stack limit of 15KB since it's small enough to trigger 20*PAGE_SIZE.
Also 15KB not a multiple of PAGE_SIZE, which is a trickier case to handle
correctly with this code.
4K pages should be fine to test with.
[kosaki.motohiro@jp.fujitsu.com: cleanup]
[akpm@linux-foundation.org: cleanup cleanup]
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Americo Wang <xiyou.wangcong@gmail.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is used by tcgetsid(3).
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
md ioctls are now handled by the md driver itself, but mdadm
may call RAID_VERSION on other devices as well. Mark the command
as IGNORE_IOCTL so this fails silently rather than printing
an annoying message.
Reported-by: "Michael S. Tsirkin" <m.s.tsirkin@gmail.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6:
cifs: fix dentry hash calculation for case-insensitive mounts
[CIFS] Don't cache timestamps on utimes due to coarse granularity
[CIFS] Maximum username length check in session setup does not match
cifs: fix length calculation for converted unicode readdir names
[CIFS] Add support for TCP_NODELAY
It was recently pointed out that the NFSERR_SERVERFAULT error, which is
designed to inform the user of a serious internal error on the server, was
being mapped to an error value that is internal to the kernel.
This patch maps it to the error EREMOTEIO, which is exported to userland
through errno.h.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org
Not having an fscache cookie is perfectly valid if the user didn't mount
with the fscache option.
This patch fixes http://bugzilla.kernel.org/show_bug.cgi?id=15234
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: stable@kernel.org
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
9p: fix p9_client_destroy unconditional calling v9fs_put_trans
9p: fix memory leak in v9fs_parse_options()
9p: Fix the kernel crash on a failed mount
9p: fix option parsing
9p: Include fsync support for 9p client
net/9p: fix statsize inside twstat
net/9p: fail when user specifies a transport which we can't find
net/9p: fix virtio transport to correctly update status on connect
Currenly, proc_devtree.c depends on asm/prom.h to include linux/of.h, to
provide some device-tree definitions (eg, struct property).
Instead, include linux/of.h directly. We still need asm/prom.h for
HAVE_ARCH_DEVTREE_FIXUPS.
Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
We only need set_node_proc_entry in proc_devtree.c, so move it there.
This fixes the !HAVE_ARCH_DEVTREE_FIXUPS build, as we can't make make
the definition in linux/of.h conditional on this #define (definitions in
asm/prom.h can't be exposed to linux/of.h, due to the enforced #include
ordering).
Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2:
ocfs2/cluster: Make o2net connect messages KERN_NOTICE
ocfs2/dlm: Fix printing of lockname
ocfs2: Fix contiguousness check in ocfs2_try_to_merge_extent_map()
ocfs2/dlm: Remove BUG_ON in dlm recovery when freeing locks of a dead node
ocfs2: Plugs race between the dc thread and an unlock ast message
ocfs2: Remove overzealous BUG_ON during blocked lock processing
ocfs2: Do not downconvert if the lock level is already compatible
ocfs2: Prevent a livelock in dlmglue
ocfs2: Fix setting of OCFS2_LOCK_BLOCKED during bast
ocfs2: Use compat_ptr in reflink_arguments.
ocfs2/dlm: Handle EAGAIN for compatibility - v2
ocfs2: Add parenthesis to wrap the check for O_DIRECT.
ocfs2: Only bug out when page size is larger than cluster size.
ocfs2: Fix memory overflow in cow_by_page.
ocfs2/dlm: Print more messages during lock migration
ocfs2/dlm: Ignore LVBs of locks in the Blocked list
ocfs2/trivial: Remove trailing whitespaces
ocfs2: fix a misleading variable name
ocfs2: Sync max_inline_data_with_xattr from tools.
ocfs2: Fix refcnt leak on ocfs2_fast_follow_link() error path
If match_strdup() fail this function exits without freeing the options string.
Signed-off-by: Venkateswararao Jujjuri <jvrao@us.ibm.com>
Sigend-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Options pointer is being moved before calling kfree() which seems
to cause problems. This uses a separate pointer to track and free
original allocation.
Signed-off-by: Venkateswararao Jujjuri <jvrao@us.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>w
Implement the fsync in the client side by marking stat field values to 'don't touch' so that server may
interpret it as a request to guarantee that the contents of the associated file are committed to stable
storage before the Rwstat message is returned.
Without this patch, calling fsync on a 9p file results in "Invalid argument" error. Please check the attached
C program.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: M. Mohan Kumar <mohan@in.ibm.com>
Acked-by: Venkateswararao Jujjuri (JV) <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Connect and disconnect messages are more than informational as they are required
during root cause analysis for failures. This patch changes them from KERN_INFO
to KERN_NOTICE.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Acked-by: Mark Faseh <mfasheh@suse.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
The debug call printing the name of the lock resource was chopping
off the last character. This patch fixes the problem.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Acked-by: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Commit f39bde24b2 fixed the error return from PUTROOTFH in the
case where there is no pseudofilesystem.
This is really a case we shouldn't hit on a correctly configured server:
in the absence of a root filehandle, there's no point accepting version
4 NFS rpc calls at all.
But the shared responsibility between kernel and userspace here means
the kernel on its own can't eliminate the possiblity of this happening.
And we have indeed gotten this wrong in distro's, so new client-side
mount code that attempts to negotiate v4 by default first has to work
around this case.
Therefore when commit f39bde24b2 arrived at roughly the same
time as the new v4-default mount code, which explicitly checked only for
the previous error, the result was previously fine mounts suddenly
failing.
We'll fix both sides for now: revert the error change, and make the
client-side mount workaround more robust.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
bsg's SG_IO doesn't work on 32-bit userspace and 64-bit kernelspace.
The problem is that both sg and bsg drivers use SG_IO
ioctl. sg_ioctl_trans() does 32/64-bit conversion even against bsg
header. It messes up bsg header. bsg driver gets garbage.
This patch fixes sg_ioctl_trans to handle only sg header (struct
sg_io_hdr).
Reported-by: Giridhar Malavali <giridhar.malavali@qlogic.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
case-insensitive mounts shouldn't use full_name_hash(). Make sure we
use the parent dentry's d_hash routine when one is set.
Reported-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
force revalidate of the file when any of the timestamps are set since
some filesytem types do not have finer granularity timestamps and
we can not always detect which file systems round timestamps down
to determine whether we can cache the mtime on setattr
samba bugzilla 3775
Acked-by: Shirish Pargaonkar <sharishp@us.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
Take ima_file_free() to proper place.
ima: rename PATH_CHECK to FILE_CHECK
ima: rename ima_path_check to ima_file_check
ima: initialize ima before inodes can be allocated
fix ima breakage
Take ima_path_check() in nfsd past dentry_open() in nfsd_open()
freeze_bdev: don't deactivate successfully frozen MS_RDONLY sb
befs: fix leak
This reverts commit 7036251180 ("tty: fix race in tty_fasync") and
commit b04da8bfdf ("fnctl: f_modown should call write_lock_irqsave/
restore") that tried to fix up some of the fallout but was incomplete.
It turns out that we really cannot hold 'tty->ctrl_lock' over calling
__f_setown, because not only did that cause problems with interrupt
disables (which the second commit fixed), it also causes a potential
ABBA deadlock due to lock ordering.
Thanks to Tetsuo Handa for following up on the issue, and running
lockdep to show the problem. It goes roughly like this:
- f_getown gets filp->f_owner.lock for reading without interrupts
disabled, so an interrupt that happens while that lock is held can
cause a lockdep chain from f_owner.lock -> sighand->siglock.
- at the same time, the tty->ctrl_lock -> f_owner.lock chain that
commit 7036251180 introduced, together with the pre-existing
sighand->siglock -> tty->ctrl_lock chain means that we have a lock
dependency the other way too.
So instead of extending tty->ctrl_lock over the whole __f_setown() call,
we now just take a reference to the 'pid' structure while holding the
lock, and then release it after having done the __f_setown. That still
guarantees that 'struct pid' won't go away from under us, which is all
we really ever needed.
Reported-and-tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Américo Wang <xiyou.wangcong@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ima_path_check actually deals with files! call it ima_file_check instead.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The "Untangling ima mess, part 2 with counters" patch messed
up the counters. Based on conversations with Al Viro, this patch
streamlines ima_path_check() by removing the counter maintaince.
The counters are now updated independently, from measuring the file,
in __dentry_open() and alloc_file() by calling ima_counts_get().
ima_path_check() is called from nfsd and do_filp_open().
It also did not measure all files that should have been measured.
Reason: ima_path_check() got bogus value passed as mask.
[AV: mea culpa]
[AV: add missing nfsd bits]
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Thanks Thomas and Christoph for testing and review.
I removed 'smp_wmb()' before up_write from the previous patch,
since up_write() should have necessary ordering constraints.
(I.e. the change of s_frozen is visible to others after up_write)
I'm quite sure the change is harmless but if you are uncomfortable
with Tested-by/Reviewed-by on the modified patch, please remove them.
If MS_RDONLY, freeze_bdev should just up_write(s_umount) instead of
deactivate_locked_super().
Also, keep sb->s_frozen consistent so that remount can check the frozen state.
Otherwise a crash reported here can happen:
http://lkml.org/lkml/2010/1/16/37http://lkml.org/lkml/2010/1/28/53
This patch should be applied for 2.6.32 stable series, too.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Thomas Backlund <tmb@mandriva.org>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: stable@kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Fix length check reported by D. Binderman (see below)
d binderman <dcb314@hotmail.com> wrote:
>
> I just ran the sourceforge tool cppcheck over the source code of the
> new Linux kernel 2.6.33-rc6
>
> It said
>
> [./cifs/sess.c:250]: (error) Buffer access out-of-bounds
May turn out to be harmless, but best to be safe. Note max
username length is defined to 32 due to Linux (Windows
maximum is 20).
Signed-off-by: Steve French <sfrench@us.ibm.com>
cifs_from_ucs2 returns the length of the converted name, including the
length of the NULL terminator. We don't want to include the NULL
terminator in the dentry name length however since that'll throw off the
hash calculation for the dentry cache.
I believe that this is the root cause of several problems that have
cropped up recently that seem to be papered over with the "noserverino"
mount option. More confirmation of that would be good, but this is
clearly a bug and it fixes at least one reproducible problem that
was reported.
This patch fixes at least this reproducer in this kernel.org bug:
http://bugzilla.kernel.org/show_bug.cgi?id=15088#c12
Reported-by: Bjorn Tore Sund <bjorn.sund@it.uib.no>
Acked-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Steve French <sfrench@us.ibm.com>
The wrong member was compared in the continguousness check.
Acked-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
Btrfs: apply updated fallocate i_size fix
Btrfs: do not try and lookup the file extent when finishing ordered io
Btrfs: Fix oopsen when dropping empty tree.
Btrfs: remove BUG_ON() due to mounting bad filesystem
Btrfs: make error return negative in btrfs_sync_file()
Btrfs: fix race between allocate and release extent buffer.
