When removing an element from the lru, this will be done today after the lock
is released. This is a clear mistake, although we are not sure if the bugs we
are seeing are related to this. All list manipulations are done inside the
lock, and so should this one.
Signed-off-by: Glauber Costa <glommer@openvz.org>
Tested-by: Michal Hocko <mhocko@suse.cz>
Cc: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Convert superblock shrinker to use the new count/scan API, and propagate
the API changes through to the filesystem callouts. The filesystem
callouts already use a count/scan API, so it's just changing counters to
longs to match the VM API.
This requires the dentry and inode shrinker callouts to be converted to
the count/scan API. This is mainly a mechanical change.
[glommer@openvz.org: use mult_frac for fractional proportions, build fixes]
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Glauber Costa <glommer@openvz.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Carlos Maiolino <cmaiolino@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Rientjes <rientjes@google.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: J. Bruce Fields <bfields@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
One of the big problems with modifying the way the dcache shrinker and LRU
implementation works is that the LRU is abused in several ways. One of
these is shrink_dentry_list().
Basically, we can move a dentry off the LRU onto a different list without
doing any accounting changes, and then use dentry_lru_prune() to remove it
from what-ever list it is now on to do the LRU accounting at that point.
This makes it -really hard- to change the LRU implementation. The use of
the per-sb LRU lock serialises movement of the dentries between the
different lists and the removal of them, and this is the only reason that
it works. If we want to break up the dentry LRU lock and lists into, say,
per-node lists, we remove the only serialisation that allows this lru
list/dispose list abuse to work.
To make this work effectively, the dispose list has to be isolated from
the LRU list - dentries have to be removed from the LRU *before* being
placed on the dispose list. This means that the LRU accounting and
isolation is completed before disposal is started, and that means we can
change the LRU implementation freely in future.
This means that dentries *must* be marked with DCACHE_SHRINK_LIST when
they are placed on the dispose list so that we don't think that parent
dentries found in try_prune_one_dentry() are on the LRU when the are
actually on the dispose list. This would result in accounting the dentry
to the LRU a second time. Hence dentry_lru_del() has to handle the
DCACHE_SHRINK_LIST case
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Glauber Costa <glommer@openvz.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Carlos Maiolino <cmaiolino@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Rientjes <rientjes@google.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: J. Bruce Fields <bfields@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
With the dentry LRUs being per-sb structures, there is no real need for
a global dentry_lru_lock. The locking can be made more fine-grained by
moving to a per-sb LRU lock, isolating the LRU operations of different
filesytsems completely from each other. The need for this is independent
of any performance consideration that may arise: in the interest of
abstracting the lru operations away, it is mandatory that each lru works
around its own lock instead of a global lock for all of them.
[glommer@openvz.org: updated changelog ]
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Glauber Costa <glommer@openvz.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Carlos Maiolino <cmaiolino@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Rientjes <rientjes@google.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: J. Bruce Fields <bfields@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Before we split up the dcache_lru_lock, the unused dentry counter needs to
be made independent of the global dcache_lru_lock. Convert it to per-cpu
counters to do this.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Glauber Costa <glommer@openvz.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Carlos Maiolino <cmaiolino@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Rientjes <rientjes@google.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: J. Bruce Fields <bfields@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The sysctl knob sysctl_vfs_cache_pressure is used to determine which
percentage of the shrinkable objects in our cache we should actively try
to shrink.
It works great in situations in which we have many objects (at least more
than 100), because the aproximation errors will be negligible. But if
this is not the case, specially when total_objects < 100, we may end up
concluding that we have no objects at all (total / 100 = 0, if total <
100).
This is certainly not the biggest killer in the world, but may matter in
very low kernel memory situations.
Signed-off-by: Glauber Costa <glommer@openvz.org>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Carlos Maiolino <cmaiolino@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Rientjes <rientjes@google.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: J. Bruce Fields <bfields@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This series reworks our current object cache shrinking infrastructure in
two main ways:
* Noticing that a lot of users copy and paste their own version of LRU
lists for objects, we put some effort in providing a generic version.
It is modeled after the filesystem users: dentries, inodes, and xfs
(for various tasks), but we expect that other users could benefit in
the near future with little or no modification. Let us know if you
have any issues.
* The underlying list_lru being proposed automatically and
transparently keeps the elements in per-node lists, and is able to
manipulate the node lists individually. Given this infrastructure, we
are able to modify the up-to-now hammer called shrink_slab to proceed
with node-reclaim instead of always searching memory from all over like
it has been doing.
Per-node lru lists are also expected to lead to less contention in the lru
locks on multi-node scans, since we are now no longer fighting for a
global lock. The locks usually disappear from the profilers with this
change.
Although we have no official benchmarks for this version - be our guest to
independently evaluate this - earlier versions of this series were
performance tested (details at
http://permalink.gmane.org/gmane.linux.kernel.mm/100537) yielding no
visible performance regressions while yielding a better qualitative
behavior in NUMA machines.
With this infrastructure in place, we can use the list_lru entry point to
provide memcg isolation and per-memcg targeted reclaim. Historically,
those two pieces of work have been posted together. This version presents
only the infrastructure work, deferring the memcg work for a later time,
so we can focus on getting this part tested. You can see more about the
history of such work at http://lwn.net/Articles/552769/
Dave Chinner (18):
dcache: convert dentry_stat.nr_unused to per-cpu counters
dentry: move to per-sb LRU locks
dcache: remove dentries from LRU before putting on dispose list
mm: new shrinker API
shrinker: convert superblock shrinkers to new API
list: add a new LRU list type
inode: convert inode lru list to generic lru list code.
dcache: convert to use new lru list infrastructure
list_lru: per-node list infrastructure
shrinker: add node awareness
fs: convert inode and dentry shrinking to be node aware
xfs: convert buftarg LRU to generic code
xfs: rework buffer dispose list tracking
xfs: convert dquot cache lru to list_lru
fs: convert fs shrinkers to new scan/count API
drivers: convert shrinkers to new count/scan API
shrinker: convert remaining shrinkers to count/scan API
shrinker: Kill old ->shrink API.
Glauber Costa (7):
fs: bump inode and dentry counters to long
super: fix calculation of shrinkable objects for small numbers
list_lru: per-node API
vmscan: per-node deferred work
i915: bail out earlier when shrinker cannot acquire mutex
hugepage: convert huge zero page shrinker to new shrinker API
list_lru: dynamically adjust node arrays
This patch:
There are situations in very large machines in which we can have a large
quantity of dirty inodes, unused dentries, etc. This is particularly true
when umounting a filesystem, where eventually since every live object will
eventually be discarded.
Dave Chinner reported a problem with this while experimenting with the
shrinker revamp patchset. So we believe it is time for a change. This
patch just moves int to longs. Machines where it matters should have a
big long anyway.
Signed-off-by: Glauber Costa <glommer@openvz.org>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Carlos Maiolino <cmaiolino@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: J. Bruce Fields <bfields@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
For a long time no filesystem has been using vfs_follow_link, and as seen
by recent filesystem submissions any new use is accidental as well.
Remove vfs_follow_link, document the replacement in
Documentation/filesystems/porting and also rename __vfs_follow_link
to match its only caller better.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull vfs pile 3 (of many) from Al Viro:
"Waiman's conversion of d_path() and bits related to it,
kern_path_mountpoint(), several cleanups and fixes (exportfs
one is -stable fodder, IMO).
There definitely will be more... ;-/"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
split read_seqretry_or_unlock(), convert d_walk() to resulting primitives
dcache: Translating dentry into pathname without taking rename_lock
autofs4 - fix device ioctl mount lookup
introduce kern_path_mountpoint()
rename user_path_umountat() to user_path_mountpoint_at()
take unlazy_walk() into umount_lookup_last()
Kill indirect include of file.h from eventfd.h, use fdget() in cgroup.c
prune_super(): sb->s_op is never NULL
exportfs: don't assume that ->iterate() won't feed us too long entries
afs: get rid of redundant ->d_name.len checks
When I moved the RCU walk termination into unlazy_walk(), I didn't copy
quite all of it: for the successful RCU termination we properly add the
necessary reference counts to our temporary copy of the root path, but
for the failure case we need to make sure that any temporary root path
information is cleared out (since it does _not_ have the proper
reference counts from the RCU lookup).
We could clean up this mess by just always dropping the temporary root
information, but Al points out that that would mean that a single lookup
through symlinks could see multiple different root entries if it races
with another thread doing chroot. Not that I think we should really
care (we had that before too, back before we had a copy of the root path
in the nameidata).
Al says he has a cunning plan. In the meantime, this is the minimal fix
for the problem, even if it's not all that pretty.
Reported-by: Mace Moneta <moneta.mace@gmail.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Let the inode verifier do it's work by returning an error when we
fail to find correct magic numbers in an inode buffer.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Saw this on generic/270 after a DQALLOC transaction overrun
shutdown:
XFS: Assertion failed: !(bip->bli_item.li_flags & XFS_LI_IN_AIL), file: fs/xfs/xfs_buf_item.c, line: 952
.....
xfs_buf_item_relse+0x4f/0xd0
xfs_buf_item_unlock+0x1b4/0x1e0
xfs_trans_free_items+0x7d/0xb0
xfs_trans_cancel+0x13c/0x1b0
xfs_symlink+0x37e/0xa60
....
When a transaction abort occured.
If we are aborting a transaction and trigger this code path, then
the item may be dirty. If the item is dirty, then it may be in the
AIL. Hence if we are aborting, we need to check if the item is in
the AIL and remove it before freeing it.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
We have quite a few places now where we do:
x = kmem_zalloc(large size)
if (!x)
x = kmem_zalloc_large(large size)
and do a similar dance when freeing the memory. kmem_free() already
does the correct freeing dance, and kmem_zalloc_large() is only ever
called in these constructs, so just factor it all into
kmem_zalloc_large() and kmem_free().
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Ever since increasing the number of supported ACLs from 25 to as
many as can fit in an xattr, there have been reports of order 4
memory allocations failing in the ACL code. Fix it in the same way
we've fixed all the xattr read/write code that has the same problem.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
When splitting the root of the da btree, we shuffled data between
buffers and the structures that track them. At one point, we copy
data and state from one buffer to another, including the ops
associated with the buffer. When we do this, we also need to copy
the buffer type associated with the buf log item so that the buffer
is logged correctly. If we don't do that, log recovery won't
recognise it and hence it won't recalculate the CRC on the buffer
after recovery. This leads to a directory block that can't be read
after recovery has run.
Found by inspection after finding the same problem with remote
symlink buffers.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
The logging of a remote symlink block does not set the buffer type
being logged, and hence on recovery the type of buffer is not
recognised and hence CRCs are not calculated after replay. This
results in log recoery throwing:
XFS (vdc): Unknown buffer type 0
errors, and subsequent reads of the symlink failing CRC
verification. Found via fsstress + godown.
Reported by: Michael L. Semon <mlsemon35@gmail.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
This is the recovery side of the btree block owner change operation
performed by swapext on CRC enabled filesystems. We detect that an
owner change is needed by the flag that has been placed on the inode
log format flag field. Because the inode recovery is being replayed
after the buffers that make up the BMBT in the given checkpoint, we
can walk all the buffers and directly modify them when we see the
flag set on an inode.
Because the inode can be relogged and hence present in multiple
chekpoints with the "change owner" flag set, we could do multiple
passes across the inode to do this change. While this isn't optimal,
we can't directly ignore the flag as there may be multiple
independent swap extent operations being replayed on the same inode
in different checkpoints so we can't ignore them.
Further, because the owner change operation uses ordered buffers, we
might have buffers that are newer on disk than the current
checkpoint and so already have the owner changed in them. Hence we
cannot just peek at a buffer in the tree and check that it has the
correct owner and assume that the change was completed.
So, for the moment just brute force the owner change every time we
see an inode with the flag set. Note that we have to be careful here
because the owner of the buffers may point to either the old owner
or the new owner. Currently the verifier can't verify the owner
directly, so there is no failure case here right now. If we verify
the owner exactly in future, then we'll have to take this into
account.
This was tested in terms of normal operation via xfstests - all of
the fsr tests now pass without failure. however, we really need to
modify xfs/227 to stress v3 inodes correctly to ensure we fully
cover this case for v5 filesystems.
In terms of recovery testing, I used a hacked version of xfs_fsr
that held the temp inode open for a few seconds before exiting so
that the filesystem could be shut down with an open owner change
recovery flags set on at least the temp inode. fsr leaves the temp
inode unlinked and in btree format, so this was necessary for the
owner change to be reliably replayed.
logprint confirmed the tmp inode in the log had the correct flag set:
INO: cnt:3 total:3 a:0x69e9e0 len:56 a:0x69ea20 len:176 a:0x69eae0 len:88
INODE: #regs:3 ino:0x44 flags:0x209 dsize:88
^^^^^
0x200 is set, indicating a data fork owner change needed to be
replayed on inode 0x44. A printk in the revoery code confirmed that
the inode change was recovered:
XFS (vdc): Mounting Filesystem
XFS (vdc): Starting recovery (logdev: internal)
recovering owner change ino 0x44
XFS (vdc): Version 5 superblock detected. This kernel L support enabled!
Use of these features in this kernel is at your own risk!
XFS (vdc): Ending recovery (logdev: internal)
The script used to test this was:
$ cat ./recovery-fsr.sh
#!/bin/bash
dev=/dev/vdc
mntpt=/mnt/scratch
testfile=$mntpt/testfile
umount $mntpt
mkfs.xfs -f -m crc=1 $dev
mount $dev $mntpt
chmod 777 $mntpt
for i in `seq 10000 -1 0`; do
xfs_io -f -d -c "pwrite $(($i * 4096)) 4096" $testfile > /dev/null 2>&1
done
xfs_bmap -vp $testfile |head -20
xfs_fsr -d -v $testfile &
sleep 10
/home/dave/src/xfstests-dev/src/godown -f $mntpt
wait
umount $mntpt
xfs_logprint -t $dev |tail -20
time mount $dev $mntpt
xfs_bmap -vp $testfile
umount $mntpt
$
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
The operation status is decoded in decode_op_hdr.
Stop the print_overflow message that is always hit without this patch:
nfs: decode_free_stateid: prematurely hit end of receive buffer. Remaining
buffer length is 0 words.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
For CRC enabled filesystems, we can't just swap inode forks from one
inode to another when defragmenting a file - the blocks in the inode
fork bmap btree contain pointers back to the owner inode. Hence if
we are to swap the inode forks we have to atomically modify every
block in the btree during the transaction.
We are doing an entire fork swap here, so we could create a new
transaction item type that indicates we are changing the owner of a
certain structure from one value to another. If we combine this with
ordered buffer logging to modify all the buffers in the tree, then
we can change the buffers in the tree without needing log space for
the operation. However, this then requires log recovery to perform
the modification of the owner information of the objects/structures
in question.
This does introduce some interesting ordering details into recovery:
we have to make sure that the owner change replay occurs after the
change that moves the objects is made, not before. Hence we can't
use a separate log item for this as we have no guarantee of strict
ordering between multiple items in the log due to the relogging
action of asynchronous transaction commits. Hence there is no
"generic" method we can use for changing the ownership of arbitrary
metadata structures.
For inode forks, however, there is a simple method of communicating
that the fork contents need the owner rewritten - we can pass a
inode log format flag for the fork for the transaction that does a
fork swap. This flag will then follow the inode fork through
relogging actions so when the swap actually gets replayed the
ownership can be changed immediately by log recovery. So that gives
us a simple method of "whole fork" exchange between two inodes.
This is relatively simple to implement, so it makes sense to do this
as an initial implementation to support xfs_fsr on CRC enabled
filesytems in the same manner as we do on existing filesystems. This
commit introduces the swapext driven functionality, the recovery
functionality will be in a separate patch.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
that force a client to purge cache pages when a server requests it.
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
to make adding new types of lease buffers easier.
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
Calling xfs_dir3_leaf_hdr_from_disk() in a verifier before
validating the magic numbers in the buffer results in ASSERT
failures due to mismatching magic numbers when a corruption occurs.
Seeing as the verifier is supposed to catch the corruption and pass
it back to the caller, having the verifier assert fail on error
defeats the purpose of detecting the errors in the first place.
Check the magic numbers direct from the buffer before decoding the
header.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
A couple of simple locking annotations and 0 vs NULL warnings.
Nothing that changes any code behaviour, just removes build noise.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
sparse reports:
fs/xfs/xfs_log_recover.c:2017:24: sparse: cast to restricted __be64
Because I used the wrong structure for the on-disk superblock cast
in 50d5c8d ("xfs: check LSN ordering for v5 superblocks during
recovery"). Fix it.
Reported-by: kbuild test robot
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
Separate "check if we need to retry" from "unlock if we are done and
had seq_writelock"; that allows to use these guys in d_walk(), where
we need to recheck every time we ascend back to parent, but do *not*
want to unlock until the very end. Lift rcu_read_lock/rcu_read_unlock
out into callers.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
For 3.12-rc1 there are a number of bugfixes in addition to work to ease usage
of shared code between libxfs and the kernel, the rest of the work to enable
project and group quotas to be used simultaneously, performance optimisations
in the log and the CIL, directory entry file type support, fixes for log space
reservations, some spelling/grammar cleanups, and the addition of user
namespace support.
- introduce readahead to log recovery
- add directory entry file type support
- fix a number of spelling errors in comments
- introduce new Q_XGETQSTATV quotactl for project quotas
- add USER_NS support
- log space reservation rework
- CIL optimisations
- kernel/userspace libxfs rework
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Merge tag 'xfs-for-linus-v3.12-rc1' of git://oss.sgi.com/xfs/xfs
Pull xfs updates from Ben Myers:
"For 3.12-rc1 there are a number of bugfixes in addition to work to
ease usage of shared code between libxfs and the kernel, the rest of
the work to enable project and group quotas to be used simultaneously,
performance optimisations in the log and the CIL, directory entry file
type support, fixes for log space reservations, some spelling/grammar
cleanups, and the addition of user namespace support.
- introduce readahead to log recovery
- add directory entry file type support
- fix a number of spelling errors in comments
- introduce new Q_XGETQSTATV quotactl for project quotas
- add USER_NS support
- log space reservation rework
- CIL optimisations
- kernel/userspace libxfs rework"
* tag 'xfs-for-linus-v3.12-rc1' of git://oss.sgi.com/xfs/xfs: (112 commits)
xfs: XFS_MOUNT_QUOTA_ALL needed by userspace
xfs: dtype changed xfs_dir2_sfe_put_ino to xfs_dir3_sfe_put_ino
Fix wrong flag ASSERT in xfs_attr_shortform_getvalue
xfs: finish removing IOP_* macros.
xfs: inode log reservations are too small
xfs: check correct status variable for xfs_inobt_get_rec() call
xfs: inode buffers may not be valid during recovery readahead
xfs: check LSN ordering for v5 superblocks during recovery
xfs: btree block LSN escaping to disk uninitialised
XFS: Assertion failed: first <= last && last < BBTOB(bp->b_length), file: fs/xfs/xfs_trans_buf.c, line: 568
xfs: fix bad dquot buffer size in log recovery readahead
xfs: don't account buffer cancellation during log recovery readahead
xfs: check for underflow in xfs_iformat_fork()
xfs: xfs_dir3_sfe_put_ino can be static
xfs: introduce object readahead to log recovery
xfs: Simplify xfs_ail_min() with list_first_entry_or_null()
xfs: Register hotcpu notifier after initialization
xfs: add xfs sb v4 support for dirent filetype field
xfs: Add write support for dirent filetype field
xfs: Add read-only support for dirent filetype field
...
Not using the return value can in the generic case be racy, so it's
in general good practice to check the return value instead.
This also resolved the warning caused on ARM and other architectures:
fs/direct-io.c: In function 'sb_init_dio_done_wq':
fs/direct-io.c:557:2: warning: value computed is not used [-Wunused-value]
Signed-off-by: Olof Johansson <olof@lixom.net>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: H Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When running the AIM7's short workload, Linus' lockref patch eliminated
most of the spinlock contention. However, there were still some left:
8.46% reaim [kernel.kallsyms] [k] _raw_spin_lock
|--42.21%-- d_path
| proc_pid_readlink
| SyS_readlinkat
| SyS_readlink
| system_call
| __GI___readlink
|
|--40.97%-- sys_getcwd
| system_call
| __getcwd
The big one here is the rename_lock (seqlock) contention in d_path()
and the getcwd system call. This patch will eliminate the need to take
the rename_lock while translating dentries into the full pathnames.
The need to take the rename_lock is to make sure that no rename
operation can be ongoing while the translation is in progress. However,
only one thread can take the rename_lock thus blocking all the other
threads that need it even though the translation process won't make
any change to the dentries.
This patch will replace the writer's write_seqlock/write_sequnlock
sequence of the rename_lock of the callers of the prepend_path() and
__dentry_path() functions with the reader's read_seqbegin/read_seqretry
sequence within these 2 functions. As a result, the code will have to
retry if one or more rename operations had been performed. In addition,
RCU read lock will be taken during the translation process to make sure
that no dentries will go away. To prevent live-lock from happening,
the code will switch back to take the rename_lock if read_seqretry()
fails for three times.
To further reduce spinlock contention, this patch does not take the
dentry's d_lock when copying the filename from the dentries. Instead,
it treats the name pointer and length as unreliable and just copy
the string byte-by-byte over until it hits a null byte or the end of
string as specified by the length. This should avoid stepping into
invalid memory address. The error cases are left to be handled by
the sequence number check.
The following code re-factoring are also made:
1. Move prepend('/') into prepend_name() to remove one conditional
check.
2. Move the global root check in prepend_path() back to the top of
the while loop.
With this patch, the _raw_spin_lock will now account for only 1.2%
of the total CPU cycles for the short workload. This patch also has
the effect of reducing the effect of running perf on its profile
since the perf command itself can be a heavy user of the d_path()
function depending on the complexity of the workload.
When taking the perf profile of the high-systime workload, the amount
of spinlock contention contributed by running perf without this patch
was about 16%. With this patch, the spinlock contention caused by
the running of perf will go away and we will have a more accurate
perf profile.
Signed-off-by: Waiman Long <Waiman.Long@hp.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Highlights include:
- Fix NFSv4 recovery so that it doesn't recover lost locks in cases such as
lease loss due to a network partition, where doing so may result in data
corruption. Add a kernel parameter to control choice of legacy behaviour
or not.
- Performance improvements when 2 processes are writing to the same file.
- Flush data to disk when an RPCSEC_GSS session timeout is imminent.
- Implement NFSv4.1 SP4_MACH_CRED state protection to prevent other
NFS clients from being able to manipulate our lease and file lockingr
state.
- Allow sharing of RPCSEC_GSS caches between different rpc clients
- Fix the broken NFSv4 security auto-negotiation between client and server
- Fix rmdir() to wait for outstanding sillyrename unlinks to complete
- Add a tracepoint framework for debugging NFSv4 state recovery issues.
- Add tracing to the generic NFS layer.
- Add tracing for the SUNRPC socket connection state.
- Clean up the rpc_pipefs mount/umount event management.
- Merge more patches from Chuck in preparation for NFSv4 migration support.
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Merge tag 'nfs-for-3.12-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs
Pull NFS client updates from Trond Myklebust:
"Highlights include:
- Fix NFSv4 recovery so that it doesn't recover lost locks in cases
such as lease loss due to a network partition, where doing so may
result in data corruption. Add a kernel parameter to control
choice of legacy behaviour or not.
- Performance improvements when 2 processes are writing to the same
file.
- Flush data to disk when an RPCSEC_GSS session timeout is imminent.
- Implement NFSv4.1 SP4_MACH_CRED state protection to prevent other
NFS clients from being able to manipulate our lease and file
locking state.
- Allow sharing of RPCSEC_GSS caches between different rpc clients.
- Fix the broken NFSv4 security auto-negotiation between client and
server.
- Fix rmdir() to wait for outstanding sillyrename unlinks to complete
- Add a tracepoint framework for debugging NFSv4 state recovery
issues.
- Add tracing to the generic NFS layer.
- Add tracing for the SUNRPC socket connection state.
- Clean up the rpc_pipefs mount/umount event management.
- Merge more patches from Chuck in preparation for NFSv4 migration
support"
* tag 'nfs-for-3.12-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (107 commits)
NFSv4: use mach cred for SECINFO_NO_NAME w/ integrity
NFS: nfs_compare_super shouldn't check the auth flavour unless 'sec=' was set
NFSv4: Allow security autonegotiation for submounts
NFSv4: Disallow security negotiation for lookups when 'sec=' is specified
NFSv4: Fix security auto-negotiation
NFS: Clean up nfs_parse_security_flavors()
NFS: Clean up the auth flavour array mess
NFSv4.1 Use MDS auth flavor for data server connection
NFS: Don't check lock owner compatability unless file is locked (part 2)
NFS: Don't check lock owner compatibility in writes unless file is locked
nfs4: Map NFS4ERR_WRONG_CRED to EPERM
nfs4.1: Add SP4_MACH_CRED write and commit support
nfs4.1: Add SP4_MACH_CRED stateid support
nfs4.1: Add SP4_MACH_CRED secinfo support
nfs4.1: Add SP4_MACH_CRED cleanup support
nfs4.1: Add state protection handler
nfs4.1: Minimal SP4_MACH_CRED implementation
SUNRPC: Replace pointer values with task->tk_pid and rpc_clnt->cl_clid
SUNRPC: Add an identifier for struct rpc_clnt
SUNRPC: Ensure rpc_task->tk_pid is available for tracepoints
...
Pull fuse bugfixes from Miklos Szeredi:
"Just a bunch of bugfixes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
fuse: use list_for_each_entry() for list traversing
fuse: readdir: check for slash in names
fuse: hotfix truncate_pagecache() issue
fuse: invalidate inode attributes on xattr modification
fuse: postpone end_page_writeback() in fuse_writepage_locked()
window. Also, most of them are bug fixes this time. Two of my
three patches (moving gfs2_sync_meta and merging the two writepage
implementations) are clean ups with the third (taking the glock ref
in examine_bucket) being a fix for a difficult to hit race condition.
The removal of an unused memory barrier is a clean up from Bob Peterson,
and the "spectator" relates to a rarely used mount option. Ben
Marzinski's patch fixes a corner case where the incorrect inode
flags were being set, resulting in incorrect behaviour on fsync.
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Merge tag 'gfs2-merge-window' of git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-nmw
Pull GFS2 updates from Steven Whitehouse:
"This is possibly the smallest ever set of GFS2 patches for a merge
window. Also, most of them are bug fixes this time.
Two of my three patches (moving gfs2_sync_meta and merging the two
writepage implementations) are clean ups with the third (taking the
glock ref in examine_bucket) being a fix for a difficult to hit race
condition.
The removal of an unused memory barrier is a clean up from Bob
Peterson, and the "spectator" relates to a rarely used mount option.
Ben Marzinski's patch fixes a corner case where the incorrect inode
flags were being set, resulting in incorrect behaviour on fsync"
* tag 'gfs2-merge-window' of git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-nmw:
GFS2: dirty inode correctly in gfs2_write_end
GFS2: Don't flag consistency error if first mounter is a spectator
GFS2: Remove unnecessary memory barrier
GFS2: Merge ordered and writeback writepage
GFS2: Take glock reference in examine_bucket()
GFS2: Move gfs2_sync_meta to lops.c
Pull ceph updates from Sage Weil:
"This includes both the first pile of Ceph patches (which I sent to
torvalds@vger, sigh) and a few new patches that add support for
fscache for Ceph. That includes a few fscache core fixes that David
Howells asked go through the Ceph tree. (Thanks go to Milosz Tanski
for putting this feature together)
This first batch of patches (included here) had (has) several
important RBD bug fixes, hole punch support, several different
cleanups in the page cache interactions, improvements in the truncate
code (new truncate mutex to avoid shenanigans with i_mutex), and a
series of fixes in the synchronous striping read/write code.
On top of that is a random collection of small fixes all across the
tree (error code checks and error path cleanup, obsolete wq flags,
etc)"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (43 commits)
ceph: use d_invalidate() to invalidate aliases
ceph: remove ceph_lookup_inode()
ceph: trivial buildbot warnings fix
ceph: Do not do invalidate if the filesystem is mounted nofsc
ceph: page still marked private_2
ceph: ceph_readpage_to_fscache didn't check if marked
ceph: clean PgPrivate2 on returning from readpages
ceph: use fscache as a local presisent cache
fscache: Netfs function for cleanup post readpages
FS-Cache: Fix heading in documentation
CacheFiles: Implement interface to check cache consistency
FS-Cache: Add interface to check consistency of a cached object
rbd: fix null dereference in dout
rbd: fix buffer size for writes to images with snapshots
libceph: use pg_num_mask instead of pgp_num_mask for pg.seed calc
rbd: fix I/O error propagation for reads
ceph: use vfs __set_page_dirty_nobuffers interface instead of doing it inside filesystem
ceph: allow sync_read/write return partial successed size of read/write.
ceph: fix bugs about handling short-read for sync read mode.
ceph: remove useless variable revoked_rdcache
...
Pull UML updates from Richard Weinberger:
"This pile contains mostly fixes and improvements for issues identified
by Richard W M Jones while adding UML as backend to libguestfs"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
um: Add irq chip um/mask handlers
um: prctl: Do not include linux/ptrace.h
um: Run UML in it's own session.
um: Cleanup SIGTERM handling
um: ubd: Introduce submit_request()
um: ubd: Add REQ_FLUSH suppport
um: Implement probe_kernel_read()
um: hostfs: Fix writeback
Prior to the introduction of page migration support in "fs/aio: Add support
to aio ring pages migration" / 36bc08cc01709b4a9bb563b35aa530241ddc63e3,
mapping of the ring buffer pages was done via get_user_pages() while
retaining mmap_sem held for write. This avoided possible races with userland
racing an munmap() or mremap(). The page migration patch, however, switched
to using mm_populate() to prime the page mapping. mm_populate() cannot be
called with mmap_sem held.
Instead of dropping the mmap_sem, revert to the old behaviour and simply
drop the use of mm_populate() since get_user_pages() will cause the pages to
get mapped anyways. Thanks to Al Viro for spotting this issue.
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
When reconnecting to automounts at startup an autofs ioctl is used
to find the device and inode of existing mounts so they can be used
to open a file descriptor of possibly covered mounts.
At this time the the caller might not yet "own" the mount so it can
trigger calling ->d_automount(). This causes automount to hang when
trying to reconnect to direct or offset mount types.
Consequently kern_path() can't be used but kern_path_mountpoint() can be.
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This is the fix that the last two commits indirectly led up to - making
sure that we don't call dput() in a bad context on the dentries we've
looked up in RCU mode after the sequence count validation fails.
This basically expands d_rcu_to_refcount() into the callers, and then
fixes the callers to delay the dput() in the failure case until _after_
we've dropped all locks and are no longer in an RCU-locked region.
The case of 'complete_walk()' was trivial, since its failure case did
the unlock_rcu_walk() directly after the call to d_rcu_to_refcount(),
and as such that is just a pure expansion of the function with a trivial
movement of the resulting dput() to after 'unlock_rcu_walk()'.
In contrast, the unlazy_walk() case was much more complicated, because
not only does convert two different dentries from RCU to be reference
counted, but it used to not call unlock_rcu_walk() at all, and instead
just returned an error and let the caller clean everything up in
"terminate_walk()".
Happily, one of the dentries in question (called "parent" inside
unlazy_walk()) is the dentry of "nd->path", which terminate_walk() wants
a refcount to anyway for the non-RCU case.
So what the new and improved unlazy_walk() does is to first turn that
dentry into a refcounted one, and once that is set up, the error cases
can continue to use the terminate_walk() helper for cleanup, but for the
non-RCU case. Which makes it possible to drop out of RCU mode if we
actually hit the sequence number failure case.
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
that prepare the code to handle different types of SMB2 leases.
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
This simplifies the RCU to refcounting code in particular.
I was originally intending to leave this for later, but walking through
all the dput() logic (see previous commit), I realized that the dput()
"might_sleep()" check was misleadingly weak. And I removed it as
misleading, both for performance profiling and for debugging.
However, the might_sleep() debugging case is actually true: the final
dput() can indeed sleep, if the inode of the dentry that you are
releasing ends up sleeping at iput time (see dentry_iput()). So the
problem with the might_sleep() in dput() wasn't that it wasn't true, it
was that it wasn't actually testing and triggering on the interesting
case.
In particular, just about *any* dput() can indeed sleep, if you happen
to race with another thread deleting the file in question, and you then
lose the race to the be the last dput() for that file. But because it's
a very rare race, the debugging code would never trigger it in practice.
Why is this problematic? The new d_rcu_to_refcount() (see commit
15570086b590: "vfs: reimplement d_rcu_to_refcount() using
lockref_get_or_lock()") does a dput() for the failure case, and it does
it under the RCU lock. So potentially sleeping really is a bug.
But there's no way I'm going to fix this with the previous complicated
"lockref_get_or_lock()" interface. And rather than revert to the old
and crufty nested dentry locking code (which did get this right by
delaying the reference count updates until they were verified to be
safe), let's make forward progress.
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is me being a bit OCD after all the dentry optimization work this
merge window: profiles end up showing 'dput()' as a rather expensive
operation, and there were two unrelated bad reasons for that.
The first reason was reading d_lockref.count for debugging purposes,
which touches the lockref cacheline (for reads) before really need to.
More importantly, the debugging test in question is _wrong_, and has
hidden bugs. It's true that we can only sleep when the count goes down
to zero, but the test as-is hides the much more subtle bug that happens
if we race with somebody else deleting the file.
Anyway we _will_ touch that cacheline, but let's do it for a write and
in the right routine (ie in "lockref_put_or_lock()") which annotates the
costs better. So remove the misleading debug code.
The other was an unnecessary access to the cacheline that contains the
d_lru list, just to check whether we already were on the LRU list or
not. This is exactly what we have d_flags for, so that we can avoid
touching extra cache lines for the common case. So just add another bit
for "is this dentry on the LRU".
Finally, mark the tests properly likely/unlikely, so that the common
fast-paths are dense in the instruction stream.
This makes the profiles look much saner.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
