We have a lot of random ints in btrfs_fs_info that can be put into flags. This
is mostly equivalent with the exception of how we deal with quota going on or
off, now instead we set a flag when we are turning it on or off and deal with
that appropriately, rather than just having a pending state that the current
quota_enabled gets set to. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
__btrfs_abort_transaction doesn't use its root parameter except to
obtain an fs_info pointer. We can obtain that from trans->root->fs_info
for now and from trans->fs_info in a later patch.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
BTRFS is using a variety of slab caches to satisfy internal needs.
Those slab caches are always allocated with the SLAB_RECLAIM_ACCOUNT,
meaning allocations from the caches are going to be accounted as
SReclaimable. At the same time btrfs is not registering any shrinkers
whatsoever, thus preventing memory from the slabs to be shrunk. This
means those caches are not in fact reclaimable.
To fix this remove the SLAB_RECLAIM_ACCOUNT on all caches apart from the
inode cache, since this one is being freed by the generic VFS super_block
shrinker. Also set the transaction related caches as SLAB_TEMPORARY,
to better document the lifetime of the objects (it just translates
to SLAB_RECLAIM_ACCOUNT).
Signed-off-by: Nikolay Borisov <n.borisov.lkml@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We reserve space for the inode update when we first reserve space for writing to
a file. However there are lots of ways that we can use this reservation and not
have it for subsequent ordered extents. Previously we'd fall through and try to
reserve metadata bytes for this, then we'd just steal the full reservation from
the delalloc_block_rsv, and if that didn't have enough space we'd steal the full
reservation from the global reserve. The problem with this is we can easily
just return ENOSPC and fallback to updating the inode item directly. In the
worst case (assuming 4k nodesize) we'd steal 64kib from the global reserve if we
fall all the way through, however if we just fallback and update the inode
directly we'd only steal 4k * BTRFS_PATH_MAX in the worst case which is 32kib.
We would have also just added the extent item for the inode so we likely will
have already cow'ed down most of the way to the leaf containing the inode item,
so we are more often than not only need one or two nodesize's worth of
reservations. Given the reservation for the extent itself is also a worst case
we will likely already have space to cover the inode update.
This change will make us behave better in the theoretical worst case, and much
better in the case that we don't have our reservation and cannot reserve more
metadata. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
So btrfs_block_rsv_migrate just unconditionally calls block_rsv_migrate_bytes.
Not only this but it unconditionally changes the size of the block_rsv. This
isn't a bug strictly speaking, but it makes truncate block rsv's look funny
because every time we migrate bytes over its size grows, even though we only
want it to be a specific size. So collapse this into one function that takes an
update_size argument and make truncate and evict not update the size for
consistency sake. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Commit fe742fd4f9 ("Revert "btrfs: switch to ->iterate_shared()"")
backed out the conversion to ->iterate_shared() for Btrfs because the
delayed inode handling in btrfs_real_readdir() is racy. However, we can
still do readdir in parallel if there are no delayed nodes.
This is a temporary fix which upgrades the shared inode lock to an
exclusive lock only when we have delayed items until we come up with a
more complete solution. While we're here, rename the
btrfs_{get,put}_delayed_items functions to make it very clear that
they're just for readdir.
Tested with xfstests and by doing a parallel kernel build:
while make tinyconfig && make -j4 && git clean dqfx; do
:
done
along with a bunch of parallel finds in another shell:
while true; do
for ((i=0; i<4; i++)); do
find . >/dev/null &
done
wait
done
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Dont print warning for ENOSPC error unless ENOSPC_DEBUG is enabled. Use
btrfs_debug if it is enabled.
Signed-off-by: Ashish Samant <ashish.samant@oracle.com>
[ preserve the WARN_ON ]
Signed-off-by: David Sterba <dsterba@suse.com>
Cleanup.
kmem_cache_destroy has support NULL argument checking,
so drop the double null testing before calling it.
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The value of ctx->pos in the last readdir call is supposed to be set to
INT_MAX due to 32bit compatibility, unless 'pos' is intentially set to a
larger value, then it's LLONG_MAX.
There's a report from PaX SIZE_OVERFLOW plugin that "ctx->pos++"
overflows (https://forums.grsecurity.net/viewtopic.php?f=1&t=4284), on a
64bit arch, where the value is 0x7fffffffffffffff ie. LLONG_MAX before
the increment.
We can get to that situation like that:
* emit all regular readdir entries
* still in the same call to readdir, bump the last pos to INT_MAX
* next call to readdir will not emit any entries, but will reach the
bump code again, finds pos to be INT_MAX and sets it to LLONG_MAX
Normally this is not a problem, but if we call readdir again, we'll find
'pos' set to LLONG_MAX and the unconditional increment will overflow.
The report from Victor at
(http://thread.gmane.org/gmane.comp.file-systems.btrfs/49500) with debugging
print shows that pattern:
Overflow: e
Overflow: 7fffffff
Overflow: 7fffffffffffffff
PAX: size overflow detected in function btrfs_real_readdir
fs/btrfs/inode.c:5760 cicus.935_282 max, count: 9, decl: pos; num: 0;
context: dir_context;
CPU: 0 PID: 2630 Comm: polkitd Not tainted 4.2.3-grsec #1
Hardware name: Gigabyte Technology Co., Ltd. H81ND2H/H81ND2H, BIOS F3 08/11/2015
ffffffff81901608 0000000000000000 ffffffff819015e6 ffffc90004973d48
ffffffff81742f0f 0000000000000007 ffffffff81901608 ffffc90004973d78
ffffffff811cb706 0000000000000000 ffff8800d47359e0 ffffc90004973ed8
Call Trace:
[<ffffffff81742f0f>] dump_stack+0x4c/0x7f
[<ffffffff811cb706>] report_size_overflow+0x36/0x40
[<ffffffff812ef0bc>] btrfs_real_readdir+0x69c/0x6d0
[<ffffffff811dafc8>] iterate_dir+0xa8/0x150
[<ffffffff811e6d8d>] ? __fget_light+0x2d/0x70
[<ffffffff811dba3a>] SyS_getdents+0xba/0x1c0
Overflow: 1a
[<ffffffff811db070>] ? iterate_dir+0x150/0x150
[<ffffffff81749b69>] entry_SYSCALL_64_fastpath+0x12/0x83
The jump from 7fffffff to 7fffffffffffffff happens when new dir entries
are not yet synced and are processed from the delayed list. Then the code
could go to the bump section again even though it might not emit any new
dir entries from the delayed list.
The fix avoids entering the "bump" section again once we've finished
emitting the entries, both for synced and delayed entries.
References: https://forums.grsecurity.net/viewtopic.php?f=1&t=4284
Reported-by: Victor <services@swwu.com>
CC: stable@vger.kernel.org
Signed-off-by: David Sterba <dsterba@suse.com>
Tested-by: Holger Hoffstätte <holger.hoffstaette@googlemail.com>
Signed-off-by: Chris Mason <clm@fb.com>
It's slightly cleaner to zero-out the delayed node upon allocation
than to do it by hand in btrfs_init_delayed_node() for a few members
Signed-off-by: Alexandru Moise <00moses.alexander00@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We need to fill inode when we found a node for it in delayed_nodes_tree.
But we did not fill the ->last_trans currently, it will cause the test
of xfstest/generic/311 fail. Scenario of the 311 is shown as below:
Problem:
(1). test_fd = open(fname, O_RDWR|O_DIRECT)
(2). pwrite(test_fd, buf, 4096, 0)
(3). close(test_fd)
(4). drop_all_caches() <-------- "echo 3 > /proc/sys/vm/drop_caches"
(5). test_fd = open(fname, O_RDWR|O_DIRECT)
(6). fsync(test_fd);
<-------- we did not get the correct log entry for the file
Reason:
When we re-open this file in (5), we would find a node
in delayed_nodes_tree and fill the inode we are lookup with the
information. But the ->last_trans is not filled, then the fsync()
will check the ->last_trans and found it's 0 then say this inode
is already in our tree which is commited, not recording the extents
for it.
Fix:
This patch fill the ->last_trans properly and set the
runtime_flags if needed in this situation. Then we can get the
log entries we expected after (6) and generic/311 passed.
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Reviewed-by: Miao Xie <miaoxie@huawei.com>
Signed-off-by: Chris Mason <clm@fb.com>
This is the second independent patch of a larger project to cleanup
btrfs's internal usage of btrfs_root. Many functions take btrfs_root
only to grab the fs_info struct.
By requiring a root these functions cause programmer overhead. That
these functions can accept any valid root is not obvious until
inspection.
This patch reduces the specificity of such functions to accept the
fs_info directly.
These patches can be applied independently and thus are not being
submitted as a patch series. There should be about 26 patches by the
project's completion. Each patch will cleanup between 1 and 34 functions
apiece. Each patch covers a single file's functions.
This patch affects the following function(s):
1) btrfs_wq_run_delayed_node
Signed-off-by: Daniel Dressler <danieru.dressler@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
This patch adds a new member to the 'struct btrfs_inode' structure to hold
the file creation time.
Signed-off-by: chandan <chandanrmail@gmail.com>
[refreshed, removed btrfs_inode_otime]
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
Commit 1d52c78afb (Btrfs: try not to ENOSPC on log replay) added a
check to skip delayed inode updates during log replay because it
confuses the enospc code. But the delayed processing will end up
ignoring delayed refs from log replay because the inode itself wasn't
put through the delayed code.
This can end up triggering a warning at commit time:
WARNING: CPU: 2 PID: 778 at fs/btrfs/delayed-inode.c:1410 btrfs_assert_delayed_root_empty+0x32/0x34()
Which is repeated for each commit because we never process the delayed
inode ref update.
The fix used here is to change btrfs_delayed_delete_inode_ref to return
an error if we're currently in log replay. The caller will do the ref
deletion immediately and everything will work properly.
Signed-off-by: Chris Mason <clm@fb.com>
cc: stable@vger.kernel.org # v3.18 and any stable series that picked 1d52c78afb
btrfs_set_key_type and btrfs_key_type are used inconsistently along with
open coded variants. Other members of btrfs_key are accessed directly
without any helpers anyway.
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
This has been reported and discussed for a long time, and this hang occurs in
both 3.15 and 3.16.
Btrfs now migrates to use kernel workqueue, but it introduces this hang problem.
Btrfs has a kind of work queued as an ordered way, which means that its
ordered_func() must be processed in the way of FIFO, so it usually looks like --
normal_work_helper(arg)
work = container_of(arg, struct btrfs_work, normal_work);
work->func() <---- (we name it work X)
for ordered_work in wq->ordered_list
ordered_work->ordered_func()
ordered_work->ordered_free()
The hang is a rare case, first when we find free space, we get an uncached block
group, then we go to read its free space cache inode for free space information,
so it will
file a readahead request
btrfs_readpages()
for page that is not in page cache
__do_readpage()
submit_extent_page()
btrfs_submit_bio_hook()
btrfs_bio_wq_end_io()
submit_bio()
end_workqueue_bio() <--(ret by the 1st endio)
queue a work(named work Y) for the 2nd
also the real endio()
So the hang occurs when work Y's work_struct and work X's work_struct happens
to share the same address.
A bit more explanation,
A,B,C -- struct btrfs_work
arg -- struct work_struct
kthread:
worker_thread()
pick up a work_struct from @worklist
process_one_work(arg)
worker->current_work = arg; <-- arg is A->normal_work
worker->current_func(arg)
normal_work_helper(arg)
A = container_of(arg, struct btrfs_work, normal_work);
A->func()
A->ordered_func()
A->ordered_free() <-- A gets freed
B->ordered_func()
submit_compressed_extents()
find_free_extent()
load_free_space_inode()
... <-- (the above readhead stack)
end_workqueue_bio()
btrfs_queue_work(work C)
B->ordered_free()
As if work A has a high priority in wq->ordered_list and there are more ordered
works queued after it, such as B->ordered_func(), its memory could have been
freed before normal_work_helper() returns, which means that kernel workqueue
code worker_thread() still has worker->current_work pointer to be work
A->normal_work's, ie. arg's address.
Meanwhile, work C is allocated after work A is freed, work C->normal_work
and work A->normal_work are likely to share the same address(I confirmed this
with ftrace output, so I'm not just guessing, it's rare though).
When another kthread picks up work C->normal_work to process, and finds our
kthread is processing it(see find_worker_executing_work()), it'll think
work C as a collision and skip then, which ends up nobody processing work C.
So the situation is that our kthread is waiting forever on work C.
Besides, there're other cases that can lead to deadlock, but the real problem
is that all btrfs workqueue shares one work->func, -- normal_work_helper,
so this makes each workqueue to have its own helper function, but only a
wraper pf normal_work_helper.
With this patch, I no long hit the above hang.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <clm@fb.com>
On heavy workloads, we're seeing soft lockup warnings on
root->inode_lock in __btrfs_release_delayed_node. The low hanging fruit
is to reduce the size of the critical section.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
Since the "_struct" suffix is mainly used for distinguish the differnt
btrfs_work between the original and the newly created one,
there is no need using the suffix since all btrfs_workers are changed
into btrfs_workqueue.
Also this patch fixed some codes whose code style is changed due to the
too long "_struct" suffix.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Replace the fs_info->delayed_workers with the newly created
btrfs_workqueue.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fb.com>
The inode reference item is close to inode item, so we insert it simultaneously
with the inode item insertion when we create a file/directory.. In fact, we also
can handle the inode reference deletion by the same way. So we made this patch to
introduce the delayed inode reference deletion for the single link inode(At most
case, the file doesn't has hard link, so we don't take the hard link into account).
This function is based on the delayed inode mechanism. After applying this patch,
we can reduce the time of the file/directory deletion by ~10%.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Two reasons:
- btrfs_end_transaction_dmeta() is the same as btrfs_end_transaction_throttle()
so it is unnecessary.
- All the delayed items should be dealt in the current transaction, so the
workers should not commit the transaction, instead, deal with the delayed
items as many as possible.
So we can remove btrfs_end_transaction_dmeta()
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
- move the condition check for wait into a function
- use wait_event_interruptible instead of prepare-schedule-finish process
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
If the number of the delayed items is greater than the upper limit, we will
try to flush all the delayed items. After that, it is unnecessary to run
them again because they are being dealt with by the wokers or the number of
them is less than the lower limit.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Before applying the patch
commit de3cb945db
title: Btrfs: improve the delayed inode throttling
We need requeue the async work after the current work was done, it
introduced a deadlock problem. So we wrote the code that this patch
removes to avoid the above problem. But after applying the above
patch, the deadlock problem didn't exist. So we should remove that
fix code.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Convert all applicable cases of printk and pr_* to the btrfs_* macros.
Fix all uses of the BTRFS prefix.
Signed-off-by: Frank Holton <fholton@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Replace kmalloc(size * nr, ) with kmalloc_array(nr, size), thus making
it easier to check is that the calculation doesn't wrap or return a smaller allocation
Signed-off-by: Dulshani Gunawardhana <dulshani.gunawardhana89@gmail.com>
Reviewed-by: Zach Brown <zab@redhat.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Use WARN_ON()'s return value in place of WARN_ON(1) for cleaner source
code that outputs a more descriptive warnings. Also fix the styling
warning of redundant braces that came up as a result of this fix.
Signed-off-by: Dulshani Gunawardhana <dulshani.gunawardhana89@gmail.com>
Reviewed-by: Zach Brown <zab@redhat.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
This patch replaces multiple atomic_inc() with atomic_add() in
delayed-inode.c to reduce source code and have few instructions
for compilation.
Reviewed-by: Zach Brown <zab@redhat.com>
Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
If the path allocation failed, we would return without decrementing
the reference count in the delayed node we got before, resulting
in a leak.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
The name buffer is not terminated by a '\0' character,
therefore it needs to be printed with %.*s and use the
length of the buffer.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
u64 is "unsigned long long" on all architectures now, so there's no need to
cast it when formatting it using the "ll" length modifier.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Some codes still use the cpu_to_lexx instead of the
BTRFS_SETGET_STACK_FUNCS declared in ctree.h.
Also added some BTRFS_SETGET_STACK_FUNCS for btrfs_header btrfs_timespec
and other structures.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Miao Xie <miaoxie@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Pull btrfs update from Chris Mason:
"These are the usual mixture of bugs, cleanups and performance fixes.
Miao has some really nice tuning of our crc code as well as our
transaction commits.
Josef is peeling off more and more problems related to early enospc,
and has a number of important bug fixes in here too"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (81 commits)
Btrfs: wait ordered range before doing direct io
Btrfs: only do the tree_mod_log_free_eb if this is our last ref
Btrfs: hold the tree mod lock in __tree_mod_log_rewind
Btrfs: make backref walking code handle skinny metadata
Btrfs: fix crash regarding to ulist_add_merge
Btrfs: fix several potential problems in copy_nocow_pages_for_inode
Btrfs: cleanup the code of copy_nocow_pages_for_inode()
Btrfs: fix oops when recovering the file data by scrub function
Btrfs: make the chunk allocator completely tree lockless
Btrfs: cleanup orphaned root orphan item
Btrfs: fix wrong mirror number tuning
Btrfs: cleanup redundant code in btrfs_submit_direct()
Btrfs: remove btrfs_sector_sum structure
Btrfs: check if we can nocow if we don't have data space
Btrfs: stop using try_to_writeback_inodes_sb_nr to flush delalloc
Btrfs: use a percpu to keep track of possibly pinned bytes
Btrfs: check for actual acls rather than just xattrs when caching no acl
Btrfs: move btrfs_truncate_page to btrfs_cont_expand instead of btrfs_truncate
Btrfs: optimize reada_for_balance
Btrfs: optimize read_block_for_search
...
Big patch, but all it does is add statics to functions which
are in fact static, then remove the associated dead-code fallout.
removed functions:
btrfs_iref_to_path()
__btrfs_lookup_delayed_deletion_item()
__btrfs_search_delayed_insertion_item()
__btrfs_search_delayed_deletion_item()
find_eb_for_page()
btrfs_find_block_group()
range_straddles_pages()
extent_range_uptodate()
btrfs_file_extent_length()
btrfs_scrub_cancel_devid()
btrfs_start_transaction_lflush()
btrfs_print_tree() is left because it is used for debugging.
btrfs_start_transaction_lflush() and btrfs_reada_detach() are
left for symmetry.
ulist.c functions are left, another patch will take care of those.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
If argument 'trans' is unnecessary in the function where
fixup_low_keys() is called, 'trans' is deleted.
Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
The delayed inode code batches up changes to the btree in hopes of doing
them in bulk. As the changes build up, processes kick off worker
threads and wait for them to make progress.
The current code kicks off an async work queue item for each delayed
node, which creates a lot of churn. It also uses a fixed 1 HZ waiting
period for the throttle, which allows us to build a lot of pending
work and can slow down the commit.
This changes us to watch a sequence counter as it is bumped during the
operations. We kick off fewer work items and have each work item do
more work.
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
We're running into having 50-100 orphans left over with xfstests 83
because of ENOSPC when trying to start the transaction for the inode update.
But in fact, it makes no sense in updating the inode for the new size while
we're deleting the stupid thing. This patch fixes this problem.
Reported-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
The delayed item commit code in several functions is similar, so
cleanup it.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
- 'nr' is no more used.
- btrfs_btree_balance_dirty() and __btrfs_btree_balance_dirty() can share
a bunch of code.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
In some places(such as: evicting inode), we just can not flush the reserved
space of delalloc, flushing the delayed directory index and delayed inode
is OK, but we don't try to flush those things and just go back when there is
no enough space to be reserved. This patch fixes this problem.
We defined 3 types of the flush operations: NO_FLUSH, FLUSH_LIMIT and FLUSH_ALL.
If we can in the transaction, we should not flush anything, or the deadlock
would happen, so use NO_FLUSH. If we flushing the reserved space of delalloc
would cause deadlock, use FLUSH_LIMIT. In the other cases, FLUSH_ALL is used,
and we will flush all things.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Pull btrfs update from Chris Mason:
"This is a large pull, with the bulk of the updates coming from:
- Hole punching
- send/receive fixes
- fsync performance
- Disk format extension allowing more hardlinks inside a single
directory (btrfs-progs patch required to enable the compat bit for
this one)
I'm cooking more unrelated RAID code, but I wanted to make sure this
original batch makes it in. The largest updates here are relatively
old and have been in testing for some time."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (121 commits)
btrfs: init ref_index to zero in add_inode_ref
Btrfs: remove repeated eb->pages check in, disk-io.c/csum_dirty_buffer
Btrfs: fix page leakage
Btrfs: do not warn_on when we cannot alloc a page for an extent buffer
Btrfs: don't bug on enomem in readpage
Btrfs: cleanup pages properly when ENOMEM in compression
Btrfs: make filesystem read-only when submitting barrier fails
Btrfs: detect corrupted filesystem after write I/O errors
Btrfs: make compress and nodatacow mount options mutually exclusive
btrfs: fix message printing
Btrfs: don't bother committing delayed inode updates when fsyncing
btrfs: move inline function code to header file
Btrfs: remove unnecessary IS_ERR in bio_readpage_error()
btrfs: remove unused function btrfs_insert_some_items()
Btrfs: don't commit instead of overcommitting
Btrfs: confirmation of value is added before trace_btrfs_get_extent() is called
Btrfs: be smarter about dropping things from the tree log
Btrfs: don't lookup csums for prealloc extents
Btrfs: cache extent state when writing out dirty metadata pages
Btrfs: do not hold the file extent leaf locked when adding extent item
...
Pull user namespace changes from Eric Biederman:
"This is a mostly modest set of changes to enable basic user namespace
support. This allows the code to code to compile with user namespaces
enabled and removes the assumption there is only the initial user
namespace. Everything is converted except for the most complex of the
filesystems: autofs4, 9p, afs, ceph, cifs, coda, fuse, gfs2, ncpfs,
nfs, ocfs2 and xfs as those patches need a bit more review.
The strategy is to push kuid_t and kgid_t values are far down into
subsystems and filesystems as reasonable. Leaving the make_kuid and
from_kuid operations to happen at the edge of userspace, as the values
come off the disk, and as the values come in from the network.
Letting compile type incompatible compile errors (present when user
namespaces are enabled) guide me to find the issues.
The most tricky areas have been the places where we had an implicit
union of uid and gid values and were storing them in an unsigned int.
Those places were converted into explicit unions. I made certain to
handle those places with simple trivial patches.
Out of that work I discovered we have generic interfaces for storing
quota by projid. I had never heard of the project identifiers before.
Adding full user namespace support for project identifiers accounts
for most of the code size growth in my git tree.
Ultimately there will be work to relax privlige checks from
"capable(FOO)" to "ns_capable(user_ns, FOO)" where it is safe allowing
root in a user names to do those things that today we only forbid to
non-root users because it will confuse suid root applications.
While I was pushing kuid_t and kgid_t changes deep into the audit code
I made a few other cleanups. I capitalized on the fact we process
netlink messages in the context of the message sender. I removed
usage of NETLINK_CRED, and started directly using current->tty.
Some of these patches have also made it into maintainer trees, with no
problems from identical code from different trees showing up in
linux-next.
After reading through all of this code I feel like I might be able to
win a game of kernel trivial pursuit."
Fix up some fairly trivial conflicts in netfilter uid/git logging code.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (107 commits)
userns: Convert the ufs filesystem to use kuid/kgid where appropriate
userns: Convert the udf filesystem to use kuid/kgid where appropriate
userns: Convert ubifs to use kuid/kgid
userns: Convert squashfs to use kuid/kgid where appropriate
userns: Convert reiserfs to use kuid and kgid where appropriate
userns: Convert jfs to use kuid/kgid where appropriate
userns: Convert jffs2 to use kuid and kgid where appropriate
userns: Convert hpfs to use kuid and kgid where appropriate
userns: Convert btrfs to use kuid/kgid where appropriate
userns: Convert bfs to use kuid/kgid where appropriate
userns: Convert affs to use kuid/kgid wherwe appropriate
userns: On alpha modify linux_to_osf_stat to use convert from kuids and kgids
userns: On ia64 deal with current_uid and current_gid being kuid and kgid
userns: On ppc convert current_uid from a kuid before printing.
userns: Convert s390 getting uid and gid system calls to use kuid and kgid
userns: Convert s390 hypfs to use kuid and kgid where appropriate
userns: Convert binder ipc to use kuids
userns: Teach security_path_chown to take kuids and kgids
userns: Add user namespace support to IMA
userns: Convert EVM to deal with kuids and kgids in it's hmac computation
...
Sometimes we need choose the method of the reservation according to the type
of the block reservation, such as the reservation for the delayed inode update.
Now we identify the type just by comparing the address of the reservation
variants, it is very ugly if it is a temporary one because we need compare it
with all the common reservation variants. So we add a new "type" field to keep
the type the reservation variants.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
We need a barrir before calling waitqueue_active otherwise we will miss
wakeups. So in places that do atomic_dec(); then atomic_read() use
atomic_dec_return() which imply a memory barrier (see memory-barriers.txt)
and then add an explicit memory barrier everywhere else that need them.
Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
The otime field is not zeroed, so users will see random otime in an old
filesystem with a new kernel which has otime support in the future.
The reserved bytes are also not zeroed, and we'll have compatibility
issue if we make use of those bytes.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Those crazy gentoo guys have been complaining about ENOSPC errors on their
portage volumes. This is because doing things like untar tends to create
lots of new files which will soak up all the reservation space in the
delayed inodes. Usually this gets papered over by the fact that we will try
and commit the transaction, however if this happens in the wrong spot or we
choose not to commit the transaction you will be screwed. So add the
ability to expclitly flush delayed inodes to free up space. Please test
this out guys to make sure it works since as usual I cannot reproduce.
Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
the items of the delayed inodes were forgotten to be freed, this patch
fixes it.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Miao pointed this out while I was working on an orphan problem that messing
with a bitfield where different ranges are protected by different locks
doesn't work out right. Turns out we've been doing this forever where we
have different parts of the bit field protected by either no lock at all or
different locks which could cause all sorts of weird problems including the
issue I was hitting. So instead make a runtime_flags thing that we use the
normal bit operations on that are all atomic so we can keep having our
no/different locking for the different flags and then make force_compress
it's own thing so it can be treated normally. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
We've been keeping around the inode sequence number in hopes that somebody
would use it, but nobody uses it and people actually use i_version which
serves the same purpose, so use i_version where we used the incore inode's
sequence number and that way the sequence is updated properly across the
board, and not just in file write. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
btrfs currently handles most errors with BUG_ON. This patch is a work-in-
progress but aims to handle most errors other than internal logic
errors and ENOMEM more gracefully.
This iteration prevents most crashes but can run into lockups with
the page lock on occasion when the timing "works out."
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
This in addition to a script in my btrfs-tracing tree will help track down space
leaks when we're getting space left over in block groups on umount. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
Btrfs: unplug every once and a while
Btrfs: deal with NULL srv_rsv in the delalloc inode reservation code
Btrfs: only set cache_generation if we setup the block group
Btrfs: don't panic if orphan item already exists
Btrfs: fix leaked space in truncate
Btrfs: fix how we do delalloc reservations and how we free reservations on error
Btrfs: deal with enospc from dirtying inodes properly
Btrfs: fix num_workers_starting bug and other bugs in async thread
BTRFS: Establish i_ops before calling d_instantiate
Btrfs: add a cond_resched() into the worker loop
Btrfs: fix ctime update of on-disk inode
btrfs: keep orphans for subvolume deletion
Btrfs: fix inaccurate available space on raid0 profile
Btrfs: fix wrong disk space information of the files
Btrfs: fix wrong i_size when truncating a file to a larger size
Btrfs: fix btrfs_end_bio to deal with write errors to a single mirror
* 'for-linus-3.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
btrfs: lower the dirty balance poll interval
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
btrfs: rename the option to nospace_cache
Btrfs: handle bio_add_page failure gracefully in scrub
Btrfs: fix deadlock caused by the race between relocation
Btrfs: only map pages if we know we need them when reading the space cache
Btrfs: fix orphan backref nodes
Btrfs: Abstract similar code for btrfs_block_rsv_add{, _noflush}
Btrfs: fix unreleased path in btrfs_orphan_cleanup()
Btrfs: fix no reserved space for writing out inode cache
Btrfs: fix nocow when deleting the item
Btrfs: tweak the delayed inode reservations again
Btrfs: rework error handling in btrfs_mount()
Btrfs: close devices on all error paths in open_ctree()
Btrfs: avoid null dereference and leaks when bailing from open_ctree()
Btrfs: fix subvol_name leak on error in btrfs_mount()
Btrfs: fix memory leak in btrfs_parse_early_options()
Btrfs: fix our reservations for updating an inode when completing io
Btrfs: fix oops on NULL trans handle in btrfs_truncate
btrfs: fix double-free 'tree_root' in 'btrfs_mount()'
Josef sent along an incremental to the inode reservation
code to make sure we try and fall back to directly updating
the inode item if things go horribly wrong.
This reworks that patch slightly, adding a fallback function
that will always try to update the inode item directly without
going through the delayed_inode code.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
People have been reporting ENOSPC crashes in finish_ordered_io. This is because
we try to steal from the delalloc block rsv to satisfy a reservation to update
the inode. The problem with this is we don't explicitly save space for updating
the inode when doing delalloc. This is kind of a problem and we've gotten away
with this because way back when we just stole from the delalloc reserve without
any questions, and this worked out fine because generally speaking the leaf had
been modified either by the mtime update when we did the original write or
because we just updated the leaf when we inserted the file extent item, only on
rare occasions had the leaf not actually been modified, and that was still ok
because we'd just use a block or two out of the over-reservation that is
delalloc.
Then came the delayed inode stuff. This is amazing, except it wants a full
reservation for updating the inode since it may do it at some point down the
road after we've written the blocks and we have to recow everything again. This
worked out because the delayed inode stuff just stole from the global reserve,
that is until recently when I changed that because it caused other problems.
So here we are, we're doing everything right and being screwed for it. So take
an extra reservation for the inode at delalloc reservation time and carry it
through the life of the delalloc reservation. If we need it we can steal it in
the delayed inode stuff. If we have already stolen it try and do a normal
metadata reservation. If that fails try to steal from the delalloc reservation.
If _that_ fails we'll get a WARN_ON() so I can start thinking of a better way to
solve this and in the meantime we'll steal from the global reserve.
With this patch I ran xfstests 13 in a loop for a couple of hours and didn't see
any problems.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (114 commits)
Btrfs: check for a null fs root when writing to the backup root log
Btrfs: fix race during transaction joins
Btrfs: fix a potential btrfs_bio leak on scrub fixups
Btrfs: rename btrfs_bio multi -> bbio for consistency
Btrfs: stop leaking btrfs_bios on readahead
Btrfs: stop the readahead threads on failed mount
Btrfs: fix extent_buffer leak in the metadata IO error handling
Btrfs: fix the new inspection ioctls for 32 bit compat
Btrfs: fix delayed insertion reservation
Btrfs: ClearPageError during writepage and clean_tree_block
Btrfs: be smarter about committing the transaction in reserve_metadata_bytes
Btrfs: make a delayed_block_rsv for the delayed item insertion
Btrfs: add a log of past tree roots
btrfs: separate superblock items out of fs_info
Btrfs: use the global reserve when truncating the free space cache inode
Btrfs: release metadata from global reserve if we have to fallback for unlink
Btrfs: make sure to flush queued bios if write_cache_pages waits
Btrfs: fix extent pinning bugs in the tree log
Btrfs: make sure btrfs_remove_free_space doesn't leak EAGAIN
Btrfs: don't wait as long for more batches during SSD log commit
...
We all keep getting those stupid warnings from use_block_rsv when running
stress.sh, and it's because the delayed insertion stuff is being stupid. It's
not the delayed insertion stuffs fault, it's all just stupid. When marking an
inode dirty for oh say updating the time on it, we just do a
btrfs_join_transaction, which doesn't reserve any space. This is stupid because
we're going to have to have space reserve to make this change, but we do it
because it's fast because chances are we're going to call it over and over again
and it doesn't matter. Well thanks to the delayed insertion stuff this is
mostly the case, so we do actually need to make this reservation. So if
trans->bytes_reserved is 0 then try to do a normal reservation. If not return
ENOSPC which will make the btrfs_dirty_inode start a proper transaction which
will let it do the whole ENOSPC dance and reserve enough space for the delayed
insertion to steal the reservation from the transaction.
The other stupid thing we do is not reserve space for the inode when writing to
the thing. Usually this is ok since we have to update the time so we'd have
already done all this work before we get to the endio stuff, so it doesn't
matter. But this is stupid because we could write the data after the
transaction commits where we changed the mtime of the inode so we have to cow
all the way down to the inode anyway. This used to be masked by the delalloc
reservation stuff, but because we delay the update it doesn't get masked in this
case. So again the delayed insertion stuff bites us in the ass. So if our
trans->block_rsv is delalloc, just steal the reservation from the delalloc
reserve. Hopefully this won't bite us in the ass, but I've said that before.
With this patch stress.sh no longer spits out those stupid warnings (famous last
words). Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
I've been hitting warnings in use_block_rsv when running the delayed insertion
stuff. It's because we will readjust global block rsv based on what is in use,
which means we could end up discarding reservations that are for the delayed
insertion stuff. So instead create a seperate block rsv for the delayed
insertion stuff. This will also make it easier to debug problems with the
delayed insertion reservations since we will know that only the delayed
insertion code touches this block_rsv. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Replace remaining direct i_nlink updates with a new set_nlink()
updater function.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
The btrfs metadata btree is the source of significant
lock contention, especially in the root node. This
commit changes our locking to use a reader/writer
lock.
The lock is built on top of rw spinlocks, and it
extends the lock tracking to remember if we have a
read lock or a write lock when we go to blocking. Atomics
count the number of blocking readers or writers at any
given time.
It removes all of the adaptive spinning from the old code
and uses only the spinning/blocking hints inside of btrfs
to decide when it should continue spinning.
In read heavy workloads this is dramatically faster. In write
heavy workloads we're still faster because of less contention
on the root node lock.
We suffer slightly in dbench because we schedule more often
during write locks, but all other benchmarks so far are improved.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
When iputting the inode, We may leave the delayed nodes if they have some
delayed items that have not been dealt with. So when the inode is read again,
we must look up the relative delayed node, and use the information in it to
initialize the inode. Or we will get inconsonant inode information, it may
cause that the same directory index number is allocated again, and hit the
following oops:
[ 5447.554187] err add delayed dir index item(name: pglog_0.965_0) into the
insertion tree of the delayed node(root id: 262, inode id: 258, errno: -17)
[ 5447.569766] ------------[ cut here ]------------
[ 5447.575361] kernel BUG at fs/btrfs/delayed-inode.c:1301!
[SNIP]
[ 5447.790721] Call Trace:
[ 5447.793191] [<ffffffffa0641c4e>] btrfs_insert_dir_item+0x189/0x1bb [btrfs]
[ 5447.800156] [<ffffffffa0651a45>] btrfs_add_link+0x12b/0x191 [btrfs]
[ 5447.806517] [<ffffffffa0651adc>] btrfs_add_nondir+0x31/0x58 [btrfs]
[ 5447.812876] [<ffffffffa0651d6a>] btrfs_create+0xf9/0x197 [btrfs]
[ 5447.818961] [<ffffffff8111f840>] vfs_create+0x72/0x92
[ 5447.824090] [<ffffffff8111fa8c>] do_last+0x22c/0x40b
[ 5447.829133] [<ffffffff8112076a>] path_openat+0xc0/0x2ef
[ 5447.834438] [<ffffffff810c58e2>] ? __perf_event_task_sched_out+0x24/0x44
[ 5447.841216] [<ffffffff8103ecdd>] ? perf_event_task_sched_out+0x59/0x67
[ 5447.847846] [<ffffffff81121a79>] do_filp_open+0x3d/0x87
[ 5447.853156] [<ffffffff811e126c>] ? strncpy_from_user+0x43/0x4d
[ 5447.859072] [<ffffffff8111f1f5>] ? getname_flags+0x2e/0x80
[ 5447.864636] [<ffffffff8111f179>] ? do_getname+0x14b/0x173
[ 5447.870112] [<ffffffff8111f1b7>] ? audit_getname+0x16/0x26
[ 5447.875682] [<ffffffff8112b1ab>] ? spin_lock+0xe/0x10
[ 5447.880882] [<ffffffff81112d39>] do_sys_open+0x69/0xae
[ 5447.886153] [<ffffffff81112db1>] sys_open+0x20/0x22
[ 5447.891114] [<ffffffff813b9aab>] system_call_fastpath+0x16/0x1b
Fix it by reusing the old delayed node.
Reported-by: Jim Schutt <jaschut@sandia.gov>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Tested-by: Jim Schutt <jaschut@sandia.gov>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Snapshot creation has two phases. One is the initial snapshot setup,
and the second is done during commit, while nobody is allowed to modify
the root we are snapshotting.
The delayed metadata insertion code can break that rule, it does a
delayed inode update on the inode of the parent of the snapshot,
and delayed directory item insertion.
This makes sure to run the pending delayed operations before we
record the snapshot root, which avoids corruptions.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
With Linus' tree, today's linux-next build (powercp ppc64_defconfig)
produced this warning:
fs/btrfs/delayed-inode.c: In function 'btrfs_delayed_update_inode':
fs/btrfs/delayed-inode.c:1598:6: warning: 'ret' may be used
uninitialized in this function
Introduced by commit 16cdcec736 ("btrfs: implement delayed inode items
operation").
This fixes a bug in btrfs_update_inode(): if the returned value from
btrfs_delayed_update_inode is a nonzero garbage, inode stat data are not
updated and several call paths may hit a BUG_ON or fail with strange
code.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: David Sterba <dsterba@suse.cz>
Changelog V5 -> V6:
- Fix oom when the memory load is high, by storing the delayed nodes into the
root's radix tree, and letting btrfs inodes go.
Changelog V4 -> V5:
- Fix the race on adding the delayed node to the inode, which is spotted by
Chris Mason.
- Merge Chris Mason's incremental patch into this patch.
- Fix deadlock between readdir() and memory fault, which is reported by
Itaru Kitayama.
Changelog V3 -> V4:
- Fix nested lock, which is reported by Itaru Kitayama, by updating space cache
inode in time.
Changelog V2 -> V3:
- Fix the race between the delayed worker and the task which does delayed items
balance, which is reported by Tsutomu Itoh.
- Modify the patch address David Sterba's comment.
- Fix the bug of the cpu recursion spinlock, reported by Chris Mason
Changelog V1 -> V2:
- break up the global rb-tree, use a list to manage the delayed nodes,
which is created for every directory and file, and used to manage the
delayed directory name index items and the delayed inode item.
- introduce a worker to deal with the delayed nodes.
Compare with Ext3/4, the performance of file creation and deletion on btrfs
is very poor. the reason is that btrfs must do a lot of b+ tree insertions,
such as inode item, directory name item, directory name index and so on.
If we can do some delayed b+ tree insertion or deletion, we can improve the
performance, so we made this patch which implemented delayed directory name
index insertion/deletion and delayed inode update.
Implementation:
- introduce a delayed root object into the filesystem, that use two lists to
manage the delayed nodes which are created for every file/directory.
One is used to manage all the delayed nodes that have delayed items. And the
other is used to manage the delayed nodes which is waiting to be dealt with
by the work thread.
- Every delayed node has two rb-tree, one is used to manage the directory name
index which is going to be inserted into b+ tree, and the other is used to
manage the directory name index which is going to be deleted from b+ tree.
- introduce a worker to deal with the delayed operation. This worker is used
to deal with the works of the delayed directory name index items insertion
and deletion and the delayed inode update.
When the delayed items is beyond the lower limit, we create works for some
delayed nodes and insert them into the work queue of the worker, and then
go back.
When the delayed items is beyond the upper bound, we create works for all
the delayed nodes that haven't been dealt with, and insert them into the work
queue of the worker, and then wait for that the untreated items is below some
threshold value.
- When we want to insert a directory name index into b+ tree, we just add the
information into the delayed inserting rb-tree.
And then we check the number of the delayed items and do delayed items
balance. (The balance policy is above.)
- When we want to delete a directory name index from the b+ tree, we search it
in the inserting rb-tree at first. If we look it up, just drop it. If not,
add the key of it into the delayed deleting rb-tree.
Similar to the delayed inserting rb-tree, we also check the number of the
delayed items and do delayed items balance.
(The same to inserting manipulation)
- When we want to update the metadata of some inode, we cached the data of the
inode into the delayed node. the worker will flush it into the b+ tree after
dealing with the delayed insertion and deletion.
- We will move the delayed node to the tail of the list after we access the
delayed node, By this way, we can cache more delayed items and merge more
inode updates.
- If we want to commit transaction, we will deal with all the delayed node.
- the delayed node will be freed when we free the btrfs inode.
- Before we log the inode items, we commit all the directory name index items
and the delayed inode update.
I did a quick test by the benchmark tool[1] and found we can improve the
performance of file creation by ~15%, and file deletion by ~20%.
Before applying this patch:
Create files:
Total files: 50000
Total time: 1.096108
Average time: 0.000022
Delete files:
Total files: 50000
Total time: 1.510403
Average time: 0.000030
After applying this patch:
Create files:
Total files: 50000
Total time: 0.932899
Average time: 0.000019
Delete files:
Total files: 50000
Total time: 1.215732
Average time: 0.000024
[1] http://marc.info/?l=linux-btrfs&m=128212635122920&q=p3
Many thanks for Kitayama-san's help!
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Reviewed-by: David Sterba <dave@jikos.cz>
Tested-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Tested-by: Itaru Kitayama <kitayama@cl.bb4u.ne.jp>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Masahiro Yamada