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... use kern_path() where possible
[folded a fix from rdd]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Code Quality According To Mingo(tm) has been vastly improved,
no code has been damaged^Wchanged^Wdamaged.
[commit message rewritten -- AV]
Signed-off-by: Manish Katiyar <mkatiyar@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Subrata Modak <subrata@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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romfs_dev_read() may return -EIO, but ret is unsigned, so the errorpath
isn't taken.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Fix ordering of LRU when moving referenced dentries to the head of the list
(they should go to the head of the list in the same order as they were found
from the tail, rather than reverse order).
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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ocfs2 was hand-calling vfs_follow_link(), but there's no point to that.
Let's use page_follow_link_light() and nd_set_link().
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Does equivalent of up_write(&s->s_umount); deactivate_super(s);
However, it does not does not unlock it until it's all over.
As the result, it's safe to use to dispose of new superblock on ->get_sb()
failure exits - nobody will see the sucker until it's all over.
Equivalent using up_write/deactivate_super is safe for that purpose
if superblock is either safe to use or has NULL ->s_root when we unlock.
Normally filesystems take the required precautions, but
a) we do have bugs in that area in some of them.
b) up_write/deactivate_super sequence is extremely common,
so the helper makes sense anyway.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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With Al Viro's patch to move privroot lookup to fs mount, there's no need
to have special code to hide the privroot in reiserfs_lookup.
I've also cleaned up the privroot hiding in reiserfs_readdir_dentry and
removed the last user of reiserfs_xattrs().
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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The security.* xattrs are ignored for xattr files, so don't create them.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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The xattr_root caching was broken from my previous patch set. It wouldn't
cause corruption, but could cause decreased performance due to allocating
a larger chunk of the journal (~ 27 blocks) than it would actually use.
This patch loads the xattr root dentry at xattr initialization and creates
it on-demand. Since we're using the cached dentry, there's no point
in keeping lookup_or_create_dir around, so that's removed.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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... even if it's a negative dentry. That way we can set ->d_op on
root before anyone could race with us. Simplify d_compare(), while
we are at it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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2.6.30-rc3 introduced some sanity checks in the VFS code to avoid NFS
bugs by ensuring that lookup_one_len is always called under i_mutex.
This patch expands the i_mutex locking to enclose lookup_one_len. This was
always required, but not not enforced in the reiserfs code since it
does locking around the xattr interactions with the xattr_sem.
This is obvious enough, and it survived an overnight 50 thread ACL test.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Push BKL down into ->umount_begin()
Signed-off-by: Alessio Igor Bogani <abogani@texware.it>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Depending on the ordering of events as we go around the
glock shrinker loop, it is possible to drop the ref count
of a glock incorrectly. It doesn't happen very often. This
patch corrects the got_ref variable, fixing the problem.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
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This fixes the following circular locking dependency problem:
=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.30-rc3 #5
-------------------------------------------------------
segctord/3895 is trying to acquire lock:
(&nilfs->ns_writer_mutex){+.+...}, at: [<d0d02172>]
nilfs_mdt_get_block+0x89/0x20f [nilfs2]
but task is already holding lock:
(&bmap->b_sem){++++..}, at: [<d0d02d99>]
nilfs_bmap_propagate+0x14/0x2e [nilfs2]
which lock already depends on the new lock.
The bugfix is done by replacing call sites of nilfs_get_writer() which
are never called from read-only context with direct dereferencing of
pointer to a writable FS-instance.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
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Some function calls in nilfs_prepare_segment_for_recovery() may fail
because they can create blocks on meta data files without configuring
a writable FS-instance. Concretely, nilfs_mdt_create_block() routine
of meta data files will fail in that case.
This fixes the problem by temporarily attaching a writable FS-instace
during the function is called.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
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* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6: (32 commits)
[CIFS] Fix double list addition in cifs posix open code
[CIFS] Allow raw ntlmssp code to be enabled with sec=ntlmssp
[CIFS] Fix SMB uid in NTLMSSP authenticate request
[CIFS] NTLMSSP reenabled after move from connect.c to sess.c
[CIFS] Remove sparse warning
[CIFS] remove checkpatch warning
[CIFS] Fix final user of old string conversion code
[CIFS] remove cifs_strfromUCS_le
[CIFS] NTLMSSP support moving into new file, old dead code removed
[CIFS] Fix endian conversion of vcnum field
[CIFS] Remove trailing whitespace
[CIFS] Remove sparse endian warnings
[CIFS] Add remaining ntlmssp flags and standardize field names
[CIFS] Fix build warning
cifs: fix length handling in cifs_get_name_from_search_buf
[CIFS] Remove unneeded QuerySymlink call and fix mapping for unmapped status
[CIFS] rename cifs_strndup to cifs_strndup_from_ucs
Added loop check when mounting DFS tree.
Enable dfs submounts to handle remote referrals.
[CIFS] Remove older session setup implementation
...
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Remove adding open file entry twice to lists in the file
Do not fill file info twice in case of posix opens and creates
Signed-off-by: Shirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
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Fix a problem where the generic block based fiemap stuff would not
properly set FIEMAP_EXTENT_LAST on the last extent. I've reworked things
to keep track if we go past the EOF, and mark the last extent properly.
The problem was reported by and tested by Eric Sandeen.
Tested-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Cc: <linux-ext4@vger.kernel.org>
Cc: <xfs-masters@oss.sgi.com>
Cc: <linux-btrfs@vger.kernel.org>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <Joel.Becker@oracle.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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There is what we believe to be a false positive reported by lockdep.
inotify_inode_queue_event() => take inotify_mutex => kernel_event() =>
kmalloc() => SLOB => alloc_pages_node() => page reclaim => slab reclaim =>
dcache reclaim => inotify_inode_is_dead => take inotify_mutex => deadlock
The plan is to fix this via lockdep annotation, but that is proving to be
quite involved.
The patch flips the allocation over to GFP_NFS to shut the warning up, for
the 2.6.30 release.
Hopefully we will fix this for real in 2.6.31. I'll queue a patch in -mm
to switch it back to GFP_KERNEL so we don't forget.
=================================
[ INFO: inconsistent lock state ]
2.6.30-rc2-next-20090417 #203
---------------------------------
inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.
kswapd0/380 [HC0[0]:SC0[0]:HE1:SE1] takes:
(&inode->inotify_mutex){+.+.?.}, at: [<ffffffff8112f1b5>] inotify_inode_is_dead+0x35/0xb0
{RECLAIM_FS-ON-W} state was registered at:
[<ffffffff81079188>] mark_held_locks+0x68/0x90
[<ffffffff810792a5>] lockdep_trace_alloc+0xf5/0x100
[<ffffffff810f5261>] __kmalloc_node+0x31/0x1e0
[<ffffffff81130652>] kernel_event+0xe2/0x190
[<ffffffff81130826>] inotify_dev_queue_event+0x126/0x230
[<ffffffff8112f096>] inotify_inode_queue_event+0xc6/0x110
[<ffffffff8110444d>] vfs_create+0xcd/0x140
[<ffffffff8110825d>] do_filp_open+0x88d/0xa20
[<ffffffff810f6b68>] do_sys_open+0x98/0x140
[<ffffffff810f6c50>] sys_open+0x20/0x30
[<ffffffff8100c272>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
irq event stamp: 690455
hardirqs last enabled at (690455): [<ffffffff81564fe4>] _spin_unlock_irqrestore+0x44/0x80
hardirqs last disabled at (690454): [<ffffffff81565372>] _spin_lock_irqsave+0x32/0xa0
softirqs last enabled at (690178): [<ffffffff81052282>] __do_softirq+0x202/0x220
softirqs last disabled at (690157): [<ffffffff8100d50c>] call_softirq+0x1c/0x50
other info that might help us debug this:
2 locks held by kswapd0/380:
#0: (shrinker_rwsem){++++..}, at: [<ffffffff810d0bd7>] shrink_slab+0x37/0x180
#1: (&type->s_umount_key#17){++++..}, at: [<ffffffff8110cfbf>] shrink_dcache_memory+0x11f/0x1e0
stack backtrace:
Pid: 380, comm: kswapd0 Not tainted 2.6.30-rc2-next-20090417 #203
Call Trace:
[<ffffffff810789ef>] print_usage_bug+0x19f/0x200
[<ffffffff81018bff>] ? save_stack_trace+0x2f/0x50
[<ffffffff81078f0b>] mark_lock+0x4bb/0x6d0
[<ffffffff810799e0>] ? check_usage_forwards+0x0/0xc0
[<ffffffff8107b142>] __lock_acquire+0xc62/0x1ae0
[<ffffffff810f478c>] ? slob_free+0x10c/0x370
[<ffffffff8107c0a1>] lock_acquire+0xe1/0x120
[<ffffffff8112f1b5>] ? inotify_inode_is_dead+0x35/0xb0
[<ffffffff81562d43>] mutex_lock_nested+0x63/0x420
[<ffffffff8112f1b5>] ? inotify_inode_is_dead+0x35/0xb0
[<ffffffff8112f1b5>] ? inotify_inode_is_dead+0x35/0xb0
[<ffffffff81012fe9>] ? sched_clock+0x9/0x10
[<ffffffff81077165>] ? lock_release_holdtime+0x35/0x1c0
[<ffffffff8112f1b5>] inotify_inode_is_dead+0x35/0xb0
[<ffffffff8110c9dc>] dentry_iput+0xbc/0xe0
[<ffffffff8110cb23>] d_kill+0x33/0x60
[<ffffffff8110ce23>] __shrink_dcache_sb+0x2d3/0x350
[<ffffffff8110cffa>] shrink_dcache_memory+0x15a/0x1e0
[<ffffffff810d0cc5>] shrink_slab+0x125/0x180
[<ffffffff810d1540>] kswapd+0x560/0x7a0
[<ffffffff810ce160>] ? isolate_pages_global+0x0/0x2c0
[<ffffffff81065a30>] ? autoremove_wake_function+0x0/0x40
[<ffffffff8107953d>] ? trace_hardirqs_on+0xd/0x10
[<ffffffff810d0fe0>] ? kswapd+0x0/0x7a0
[<ffffffff8106555b>] kthread+0x5b/0xa0
[<ffffffff8100d40a>] child_rip+0xa/0x20
[<ffffffff8100cdd0>] ? restore_args+0x0/0x30
[<ffffffff81065500>] ? kthread+0x0/0xa0
[<ffffffff8100d400>] ? child_rip+0x0/0x20
[eparis@redhat.com: fix audit too]
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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If lockd is signalled soon enough after restart then locks_start_grace()
will try to re-add an entry to a list and trigger a lock corruption
warning.
Thanks to Wang Chen for the problem report and diagnosis.
WARNING: at lib/list_debug.c:26 __list_add+0x27/0x5c()
...
list_add corruption. next->prev should be prev (ef8fe958), but was ef8ff128. (next=ef8ff128).
...
Pid: 23062, comm: lockd Tainted: G W 2.6.30-rc2 #3
Call Trace:
[<c042d5b5>] warn_slowpath+0x71/0xa0
[<c0422a96>] ? update_curr+0x11d/0x125
[<c044b12d>] ? trace_hardirqs_on_caller+0x18/0x150
[<c044b270>] ? trace_hardirqs_on+0xb/0xd
[<c051c61a>] ? _raw_spin_lock+0x53/0xfa
[<c051c89f>] __list_add+0x27/0x5c
[<ef8f6daa>] locks_start_grace+0x22/0x30 [lockd]
[<ef8f34da>] set_grace_period+0x39/0x53 [lockd]
[<c06b8921>] ? lock_kernel+0x1c/0x28
[<ef8f3558>] lockd+0x64/0x164 [lockd]
[<c044b12d>] ? trace_hardirqs_on_caller+0x18/0x150
[<c04227b0>] ? complete+0x34/0x3e
[<ef8f34f4>] ? lockd+0x0/0x164 [lockd]
[<ef8f34f4>] ? lockd+0x0/0x164 [lockd]
[<c043dd42>] kthread+0x45/0x6b
[<c043dcfd>] ? kthread+0x0/0x6b
[<c0403c23>] kernel_thread_helper+0x7/0x10
Reported-by: Wang Chen <wangchen@cn.fujitsu.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Cc: stable@kernel.org
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After 2f9092e1020246168b1309b35e085ecd7ff9ff72 "Fix i_mutex vs. readdir
handling in nfsd" (and 14f7dd63 "Copy XFS readdir hack into nfsd code"),
an entry may be removed between the first mutex_unlock and the second
mutex_lock. In this case, lookup_one_len() will return a negative
dentry. Check for this case to avoid a NULL dereference.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Reviewed-by: J. R. Okajima <hooanon05@yahoo.co.jp>
Cc: stable@kernel.org
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On mount, "sec=ntlmssp" can now be specified to allow
"rawntlmssp" security to be enabled during
CIFS session establishment/authentication (ntlmssp used to
require specifying krb5 which was counterintuitive).
Signed-off-by: Steve French <sfrench@us.ibm.com>
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We were not setting the SMB uid in NTLMSSP authenticate
request which could lead to INVALID_PARAMETER error
on 2nd session setup.
Signed-off-by: Steve French <sfrench@us.ibm.com>
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By using the same test as is used for /proc/pid/maps and /proc/pid/smaps,
only allow processes that can ptrace() a given process to see information
that might be used to bypass address space layout randomization (ASLR).
These include eip, esp, wchan, and start_stack in /proc/pid/stat as well
as the non-symbolic output from /proc/pid/wchan.
ASLR can be bypassed by sampling eip as shown by the proof-of-concept
code at http://code.google.com/p/fuzzyaslr/ As part of a presentation
(http://www.cr0.org/paper/to-jt-linux-alsr-leak.pdf) esp and wchan were
also noted as possibly usable information leaks as well. The
start_stack address also leaks potentially useful information.
Cc: Stable Team <stable@kernel.org>
Signed-off-by: Jake Edge <jake@lwn.net>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The NTLMSSP code was removed from fs/cifs/connect.c and merged
(75% smaller, cleaner) into fs/cifs/sess.c
As with the old code it requires that cifs be built with
CONFIG_CIFS_EXPERIMENTAL, the /proc/fs/cifs/Experimental flag
must be set to 2, and mount must turn on extended security
(e.g. with sec=krb5).
Although NTLMSSP encapsulated in SPNEGO is not enabled yet,
"raw" ntlmssp is common and useful in some cases since it
offers more complete security negotiation, and is the
default way of negotiating security for many Windows systems.
SPNEGO encapsulated NTLMSSP will be able to reuse the same
code.
Signed-off-by: Steve French <sfrench@us.ibm.com>
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The session and slots are allocated all in one piece.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
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Follow up to Nick Piggin's patches to ensure that nfs_vm_page_mkwrite
returns with the page lock held, and sets the VM_FAULT_LOCKED flag.
See http://bugzilla.kernel.org/show_bug.cgi?id=12913
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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* 'for-linus' of git://oss.sgi.com/xfs/xfs:
xfs: fix getbmap vs mmap deadlock
xfs: a couple getbmap cleanups
xfs: add more checks to superblock validation
xfs_file_last_byte() needs to acquire ilock
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git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/configfs
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/configfs:
configfs: Fix Trivial Warning in fs/configfs/symlink.c
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git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2:
ocfs2: Change repository in MAINTAINERS.
ocfs2: Fix a missing credit when deleting from indexed directories.
ocfs2/trivial: Remove unused variable in ocfs2_rename.
ocfs2: Add missing iput() during error handling in ocfs2_dentry_attach_lock()
ocfs2: Fix some printk() warnings.
ocfs2: Fix 2 warning during ocfs2 make.
ocfs2: Reserve 1 more cluster in expanding_inline_dir for indexed dir.
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->real_parent is the parent. ->parent may be the tracer.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The Committed_AS field can underflow in certain situations:
> # while true; do cat /proc/meminfo | grep _AS; sleep 1; done | uniq -c
> 1 Committed_AS: 18446744073709323392 kB
> 11 Committed_AS: 18446744073709455488 kB
> 6 Committed_AS: 35136 kB
> 5 Committed_AS: 18446744073709454400 kB
> 7 Committed_AS: 35904 kB
> 3 Committed_AS: 18446744073709453248 kB
> 2 Committed_AS: 34752 kB
> 9 Committed_AS: 18446744073709453248 kB
> 8 Committed_AS: 34752 kB
> 3 Committed_AS: 18446744073709320960 kB
> 7 Committed_AS: 18446744073709454080 kB
> 3 Committed_AS: 18446744073709320960 kB
> 5 Committed_AS: 18446744073709454080 kB
> 6 Committed_AS: 18446744073709320960 kB
Because NR_CPUS can be greater than 1000 and meminfo_proc_show() does
not check for underflow.
But NR_CPUS proportional isn't good calculation. In general,
possibility of lock contention is proportional to the number of online
cpus, not theorical maximum cpus (NR_CPUS).
The current kernel has generic percpu-counter stuff. using it is right
way. it makes code simplify and percpu_counter_read_positive() don't
make underflow issue.
Reported-by: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Eric B Munson <ebmunson@us.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: <stable@kernel.org> [All kernel versions]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This fixes the problem introduced by commit 3bfacef412 (get rid of
special-casing the /sbin/loader on alpha): osf/1 ecoff binary segfaults
when binfmt_aout built as module. That happens because aout binary
handler gets on the top of the binfmt list due to late registration, and
kernel attempts to execute the binary without preparatory work that must
be done by binfmt_loader.
Fixed by changing the registration order of the default binfmt handlers
using list_add_tail() and introducing insert_binfmt() function which
places new handler on the top of the binfmt list. This might be generally
useful for installing arch-specific frontends for default handlers or just
for overriding them.
Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Richard Henderson <rth@twiddle.net
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The intention of commit aae8679b0ebcaa92f99c1c3cb0cd651594a43915
("pagemap: fix bug in add_to_pagemap, require aligned-length reads of
/proc/pid/pagemap") was to force reads of /proc/pid/pagemap to be a
multiple of 8 bytes, but now it allows to read 0 bytes, which actually
puts some data to user's buffer. According to POSIX, if count is zero,
read() should return zero and has no other results.
Signed-off-by: Vitaly Mayatskikh <v.mayatskih@gmail.com>
Cc: Thomas Tuttle <ttuttle@google.com>
Acked-by: Matt Mackall <mpm@selenic.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Change page_mkwrite to allow implementations to return with the page
locked, and also change it's callers (in page fault paths) to hold the
lock until the page is marked dirty. This allows the filesystem to have
full control of page dirtying events coming from the VM.
Rather than simply hold the page locked over the page_mkwrite call, we
call page_mkwrite with the page unlocked and allow callers to return with
it locked, so filesystems can avoid LOR conditions with page lock.
The problem with the current scheme is this: a filesystem that wants to
associate some metadata with a page as long as the page is dirty, will
perform this manipulation in its ->page_mkwrite. It currently then must
return with the page unlocked and may not hold any other locks (according
to existing page_mkwrite convention).
In this window, the VM could write out the page, clearing page-dirty. The
filesystem has no good way to detect that a dirty pte is about to be
attached, so it will happily write out the page, at which point, the
filesystem may manipulate the metadata to reflect that the page is no
longer dirty.
It is not always possible to perform the required metadata manipulation in
->set_page_dirty, because that function cannot block or fail. The
filesystem may need to allocate some data structure, for example.
And the VM cannot mark the pte dirty before page_mkwrite, because
page_mkwrite is allowed to fail, so we must not allow any window where the
page could be written to if page_mkwrite does fail.
This solution of holding the page locked over the 3 critical operations
(page_mkwrite, setting the pte dirty, and finally setting the page dirty)
closes out races nicely, preventing page cleaning for writeout being
initiated in that window. This provides the filesystem with a strong
synchronisation against the VM here.
- Sage needs this race closed for ceph filesystem.
- Trond for NFS (http://bugzilla.kernel.org/show_bug.cgi?id=12913).
- I need it for fsblock.
- I suspect other filesystems may need it too (eg. btrfs).
- I have converted buffer.c to the new locking. Even simple block allocation
under dirty pages might be susceptible to i_size changing under partial page
at the end of file (we also have a buffer.c-side problem here, but it cannot
be fixed properly without this patch).
- Other filesystems (eg. NFS, maybe btrfs) will need to change their
page_mkwrite functions themselves.
[ This also moves page_mkwrite another step closer to fault, which should
eventually allow page_mkwrite to be moved into ->fault, and thus avoiding a
filesystem calldown and page lock/unlock cycle in __do_fault. ]
[akpm@linux-foundation.org: fix derefs of NULL ->mapping]
Cc: Sage Weil <sage@newdream.net>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Fix an obvious incorrect return status in autofs4_mount_busy().
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Signed-off-by: Steve French <sfrench@us.ibm.com>
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Signed-off-by: Steve French <sfrench@us.ibm.com>
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Signed-off-by: Steve French <sfrench@us.ibm.com>
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Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
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Remove dead NTLMSSP support from connect.c prior to addition of
the new code to replace it.
Signed-off-by: Steve French <sfrench@us.ibm.com>
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When multiply mounting from the same client to the same server, with
different userids, we create a vcnum which should be unique if
possible (this is not the same as the smb uid, which is the handle
to the security context). We were not endian converting additional
(beyond the first which is zero) vcnum properly.
CC: Stable <stable@kernel.org>
Acked-by: Shirish Pargaonkar <shirishp@us.ibm.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
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Signed-off-by: Steve French <sfrench@us.ibm.com>
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Removes two sparse CHECK_ENDIAN warnings from Jeffs earlier patch,
and removes the dead readlink code (after noting where in
findfirst we will need to add something like that in the future
to handle the newly discovered unexpected error on FindFirst of NTFS symlinks.
Signed-off-by: Steve French <sfrench@us.ibm.com>
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Signed-off-by: Steve French <sfrench@us.ibm.com>
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Signed-off-by: Steve French <sfrench@us.ibm.com>
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The earlier patch to move this code to use the new unicode helpers
assumed that the filename strings would be null terminated. That's not
always the case.
Instead of passing "max_len" to the string converter, pass "min(len,
max_len)", which makes it do the right thing while still keeping the
parser confined to the response. Also fix up the prototypes of this
function and the callers so that max_len is unsigned (like len is).
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
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