Drop spin lock in convert_extent_bit() when memory alloc fails,
otherwise, it will be a deadlock.
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
If we call ioctl(BTRFS_IOC_ADD_DEV) directly, we'll succeed in adding
a readonly device to a btrfs filesystem, and btrfs will write to
that device, emitting kernel errors:
[ 3109.833692] lost page write due to I/O error on loop2
[ 3109.833720] lost page write due to I/O error on loop2
...
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
When we find an existing cluster, we switch to its block group as the
current block group, possibly skipping multiple blocks in the process.
Furthermore, under heavy contention, multiple threads may fail to
allocate from a cluster and then release just-created clusters just to
proceed to create new ones in a different block group.
This patch tries to allocate from an existing cluster regardless of its
block group, and doesn't switch to that group, instead proceeding to
try to allocate a cluster from the group it was iterating before the
attempt.
Signed-off-by: Alexandre Oliva <oliva@lsd.ic.unicamp.br>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
If we reach LOOP_NO_EMPTY_SIZE, we won't even try to use a cluster that
others might have set up. Odds are that there won't be one, but if
someone else succeeded in setting it up, we might as well use it, even
if we don't try to set up a cluster again.
Signed-off-by: Alexandre Oliva <oliva@lsd.ic.unicamp.br>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Commit 4a54c8c16 introduced raid-repair, killing the individual
readpage_io_failed_hook entries from inode.c and disk-io.c. Commit
4bb31e92 introduced new readahead code, adding a readpage_io_failed_hook to
disk-io.c.
The raid-repair commit had logic to disable raid-repair, if
readpage_io_failed_hook is set. Thus, the readahead commit effectively
disabled raid-repair for meta data.
This commit changes the logic to always attempt raid-repair when needed and
call the readpage_io_failed_hook in case raid-repair fails. This is much
more straight forward and should have been like that from the beginning.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Reported-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
If we don't have a cluster, don't bother trying to allocate from it,
jumping right away to the attempt to allocate a new cluster.
Signed-off-by: Alexandre Oliva <oliva@lsd.ic.unicamp.br>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
We test whether a block group has enough free space to hold the
requested block, but when we're doing clustered allocation, we can
save some cycles by testing whether it has enough room for the cluster
upfront, otherwise we end up attempting to set up a cluster and
failing. Only in the NO_EMPTY_SIZE loop do we attempt an unclustered
allocation, and by then we'll have zeroed the cluster size, so this
patch won't stop us from using the block group as a last resort.
Signed-off-by: Alexandre Oliva <oliva@lsd.ic.unicamp.br>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Instead of starting at zero (offset is always zero), request a cluster
starting at search_start, that denotes the beginning of the current
block group.
Signed-off-by: Alexandre Oliva <oliva@lsd.ic.unicamp.br>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The field that indicates the size of the largest contiguous chunk of
free space in the cluster is not initialized when setting up bitmaps,
it's only increased when we find a larger contiguous chunk. We end up
retaining a larger value than appropriate for highly-fragmented
clusters, which may cause pointless searches for large contiguous
groups, and even cause clusters that do not meet the density
requirements to be set up.
Signed-off-by: Alexandre Oliva <oliva@lsd.ic.unicamp.br>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
We're failing to create clusters with bitmaps because
setup_cluster_no_bitmap checks that the list is empty before inserting
the bitmap entry in the list for setup_cluster_bitmap, but the list
field is only initialized when it is restored from the on-disk free
space cache, or when it is written out to disk.
Besides a potential race condition due to the multiple use of the list
field, filesystem performance severely degrades over time: as we use
up all non-bitmap free extents, the try-to-set-up-cluster dance is
done at every metadata block allocation. For every block group, we
fail to set up a cluster, and after failing on them all up to twice,
we fall back to the much slower unclustered allocation.
To make matters worse, before the unclustered allocation, we try to
create new block groups until we reach the 1% threshold, which
introduces additional bitmaps and thus block groups that we'll iterate
over at each metadata block request.
To reproduce this bug:
# dd if=/dev/zero of=img bs=1M count=256
# mkfs.btrfs img
# losetup -r /dev/loop1 img
# mount /dev/loop1 /mnt
OOPS!!
It triggered BUG_ON(!nr_devices) in btrfs_calc_avail_data_space().
To fix this, instead of checking write-only devices, we check all open
deivces:
# df -h /dev/loop1
Filesystem Size Used Avail Use% Mounted on
/dev/loop1 250M 28K 238M 1% /mnt
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
It seems overly harsh to fail a resize of a btrfs file system to the
same size when a shrink or grow would succeed. User app GParted trips
over this error. Allow it by bypassing the shrink or grow operation.
Signed-off-by: Mike Fleetwood <mike.fleetwood@googlemail.com>
When I ran the xfstests, I found the test tasks was blocked on meta-data
reservation.
By debugging, I found the reason of this bug:
start transaction
|
v
reserve meta-data space
|
v
flush delay allocation -> iput inode -> evict inode
^ |
| v
wait for delay allocation flush <- reserve meta-data space
And besides that, the flush on evicting inode will block the thread, which
is reclaiming the memory, and make oom happen easily.
Fix this bug by skipping the flush step when evicting inode.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
The location of the btrfs-progs repository has been changed.
This patch updates the documentation accordingly.
Signed-off-by: Arnd Hannemann <arnd@arndnet.de>
The log replay code only partially loads block groups, since
the block group caching code is able to detect and deal with
extents the logging code has pinned down.
While the logging code is pinning down block groups, there is
a bogus WARN_ON we're hitting if the code wasn't able to find
an extent in the cache. This commit removes the warning because
it can happen any time there isn't a valid free space cache
for that block group.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
We've been hitting BUG()'s in btrfs_cont_expand and btrfs_fallocate and anywhere
else that calls btrfs_get_extent while running xfstests 13 in a loop. This is
because fiemap is calling btrfs_get_extent with non-sectorsize aligned offsets,
which will end up adding mappings that are not sectorsize aligned, which will
cause problems in some cases for subsequent calls to btrfs_get_extent for
similar areas that are sectorsize aligned. With this patch I ran xfstests 13 in
a loop for a couple of hours and didn't hit the problem that I could previously
hit in at most 20 minutes. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
When doing the io_ctl helpers to clean up the free space cache stuff I stopped
using our normal prepare_pages stuff, which means I of course forgot to do
things like set the pages extent mapped, which will cause us all sorts of
wonderful propblems. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
We've been hitting panics when running xfstest 13 in a loop for long periods of
time. And actually this problem has always existed so we've been hitting these
things randomly for a while. Basically what happens is we get a thread coming
into the allocator and reading the space cache off of disk and adding the
entries to the free space cache as we go. Then we get another thread that comes
in and tries to allocate from that block group. Since block_group->cached !=
BTRFS_CACHE_NO it goes ahead and tries to do the allocation. We do this because
if we're doing the old slow way of caching we don't want to hold people up and
wait for everything to finish. The problem with this is we could end up
discarding the space cache at some arbitrary point in the future, which means we
could very well end up allocating space that is either bad, or when the real
caching happens it could end up thinking the space isn't in use when it really
is and cause all sorts of other problems.
The solution is to add a new flag to indicate we are loading the free space
cache from disk, and always try to cache the block group if cache->cached !=
BTRFS_CACHE_FINISHED. That way if we are loading the space cache anybody else
who tries to allocate from the block group will have to wait until it's finished
to make sure it completes successfully. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
For the user it is confusing to find something like:
[10197.627710] new size for /dev/mapper/vg0-usr_share is 3221225472
in kernel log, because it doesn't point directly to btrfs.
This patch prefixes those messages with "btrfs:" like other btrfs
related printks.
Signed-off-by: Arnd Hannemann <arnd@arndnet.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Round inode bytes and delalloc bytes up to real blocksize before
converting to sector size. Otherwise eg. files smaller than 512
are reported with zero blocks due to incorrect rounding.
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
setup_cluster_no_bitmap() searches all the extents and bitmaps starting
from offset. Therefore if it returns -ENOSPC, all the bitmaps starting
from offset are in the bitmaps list, so it's sufficient to search from
this list in setup_cluser_bitmap().
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Suppose there are two bitmaps [0, 256], [256, 512] and one extent
[100, 120] in the free space cache, and we want to setup a cluster
with offset=100, bytes=50.
In this case, there will be only one bitmap [256, 512] in the temporary
bitmaps list, and then setup_cluster_bitmap() won't search bitmap [0, 256].
The cause is, the list is constructed in setup_cluster_no_bitmap(),
and only bitmaps with bitmap_entry->offset >= offset will be added
into the list, and the very bitmap that convers offset has
bitmap_entry->offset <= offset.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
My previous patch introduced some u64 for failed_mirror variables, this one
makes it consistent again.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This patch casts to unsigned long before casting to a pointer and fixes
the following warnings:
fs/btrfs/extent_io.c:2289:20: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
fs/btrfs/ioctl.c:2933:37: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
fs/btrfs/ioctl.c:2937:21: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
fs/btrfs/ioctl.c:3020:21: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
fs/btrfs/scrub.c:275:4: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
fs/btrfs/backref.c:686:27: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
When btrfs is writing the super blocks, it send barrier flushes to make
sure writeback caching drives get all the metadata on disk in the
right order.
But, we have two bugs in the way these are sent down. When doing
full commits (not via the tree log), we are sending the barrier down
before the last super when it should be going down before the first.
In multi-device setups, we should be waiting for the barriers to
complete on all devices before writing any of the supers.
Both of these bugs can cause corruptions on power failures. We fix it
with some new code to send down empty barriers to all devices before
writing the first super.
Alexandre Oliva found the multi-device bug. Arne Jansen did the async
barrier loop.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Reported-by: Alexandre Oliva <oliva@lsd.ic.unicamp.br>
The btrfs snapshotting code requires that once a root has been
snapshotted, we don't change it during a commit.
But there are two cases to lead to tree corruptions:
1) multi-thread snapshots can commit serveral snapshots in a transaction,
and this may change the src root when processing the following pending
snapshots, which lead to the former snapshots corruptions;
2) the free inode cache was changing the roots when it root the cache,
which lead to corruptions.
This fixes things by making sure we force COW the block after we create a
snapshot during commiting a transaction, then any changes to the roots
will result in COW, and we get all the fs roots and snapshot roots to be
consistent.
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Rename no_space_cache option to nospace_cache to be more consistent with
the rest, where the simple prefix 'no' is used to negate an option.
The option has been introduced during the -rc1 cycle and there are has not been
widely used, so it's safe.
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Currently scrub fails with ENOMEM when bio_add_page fails. Unfortunately
dm based targets accept only one page per bio, thus making scrub always
fails. This patch just submits the current bio when an error is encountered
and starts a new one.
Signed-off-by: Arne Jansen <sensille@gmx.net>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
We can not do flushable reservation for the relocation when we create snapshot,
because it may make the transaction commit task and the flush task wait for
each other and the deadlock happens.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
People have been running into a warning when loading space cache because the
page is already mapped when trying to read in a bitmap. The way we read in
entries and pages is kind of convoluted, so fix it so that io_ctl_read_entry
maps the entries if it needs to, and if it hits the end of the page it simply
unmaps the page. That way we can unconditionally unmap the io_ctl before
reading in the bitmap and we should stop hitting these warnings. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
If the root node of a fs/file tree is in the block group that is
being relocated, but the others are not in the other block groups.
when we create a snapshot for this tree between the relocation tree
creation ends and ->create_reloc_tree is set to 0, Btrfs will create
some backref nodes that are the lowest nodes of the backrefs cache.
But we forget to add them into ->leaves list of the backref cache
and deal with them, and at last, they will triggered BUG_ON().
kernel BUG at fs/btrfs/relocation.c:239!
This patch fixes it by adding them into ->leaves list of backref cache.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
btrfs_block_rsv_add{, _noflush}() have similar code, so abstract that code.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
When we did stress test for the space relocation, the deadlock happened.
By debugging, We found it was caused by the carelessness that we forgot
to unlock the read lock of the extent buffers in btrfs_orphan_cleanup()
before we end the transaction handle, so the transaction commit task waited
the task, which called btrfs_orphan_cleanup(), to unlock the extent buffer,
but that task waited the commit task to end the transaction commit, and
the deadlock happened. Fix it.
Signed-ff-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
I-node cache forgets to reserve the space when writing out it. And when
we do some stress test, such as synctest, it will trigger WARN_ON() in
use_block_rsv().
WARNING: at fs/btrfs/extent-tree.c:5718 btrfs_alloc_free_block+0xbf/0x281 [btrfs]()
...
Call Trace:
[<ffffffff8104df86>] warn_slowpath_common+0x80/0x98
[<ffffffff8104dfb3>] warn_slowpath_null+0x15/0x17
[<ffffffffa0369c60>] btrfs_alloc_free_block+0xbf/0x281 [btrfs]
[<ffffffff810cbcb8>] ? __set_page_dirty_nobuffers+0xfe/0x108
[<ffffffffa035c040>] __btrfs_cow_block+0x118/0x3b5 [btrfs]
[<ffffffffa035c7ba>] btrfs_cow_block+0x103/0x14e [btrfs]
[<ffffffffa035e4c4>] btrfs_search_slot+0x249/0x6a4 [btrfs]
[<ffffffffa036d086>] btrfs_lookup_inode+0x2a/0x8a [btrfs]
[<ffffffffa03788b7>] btrfs_update_inode+0xaa/0x141 [btrfs]
[<ffffffffa036d7ec>] btrfs_save_ino_cache+0xea/0x202 [btrfs]
[<ffffffffa03a761e>] ? btrfs_update_reloc_root+0x17e/0x197 [btrfs]
[<ffffffffa0373867>] commit_fs_roots+0xaa/0x158 [btrfs]
[<ffffffffa03746a6>] btrfs_commit_transaction+0x405/0x731 [btrfs]
[<ffffffff810690df>] ? wake_up_bit+0x25/0x25
[<ffffffffa039d652>] ? btrfs_log_dentry_safe+0x43/0x51 [btrfs]
[<ffffffffa0381c5f>] btrfs_sync_file+0x16a/0x198 [btrfs]
[<ffffffff81122806>] ? mntput+0x21/0x23
[<ffffffff8112d150>] vfs_fsync_range+0x18/0x21
[<ffffffff8112d170>] vfs_fsync+0x17/0x19
[<ffffffff8112d316>] do_fsync+0x29/0x3e
[<ffffffff8112d348>] sys_fsync+0xb/0xf
[<ffffffff81468352>] system_call_fastpath+0x16/0x1b
Sometimes it causes BUG_ON() in the reservation code of the delayed inode
is triggered.
So we must reserve enough space for inode cache.
Note: If we can not reserve the enough space for inode cache, we will
give up writing out it.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
btrfs_previous_item() just search the b+ tree, do not COW the nodes or leaves,
if we modify the result of it, the meta-data will be broken. fix it.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
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>
Commits 6c41761f and 45ea6095 introduced the possibility of NULL pointer
dereference on error paths, also we would leave all devices busy and
leak fs_info with all sub-structures on error when trying to mount an
already mounted fs to a different directory.
Fix this by doing all allocations before trying to open any of the
devices, adjust error path for mount-already-mounted-fs case.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Fix a bug introduced by 7e662854 where we would leave devices busy on
certain error paths in open_ctree(). fs_info is guaranteed to be
non-NULL now so it's safe to dereference it on all error paths.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Fix bugs introduced by 6c41761f. Firstly, after failing to allocate any
of the tree roots (first 'goto fail' in open_ctree()) we would
dereference a NULL fs_info pointer in free_fs_info(). Secondly, after
failures from init_srcu_struct(), setup_bdi() and new_inode() we would
leak all earlier allocated roots: fs_info fields haven't been
initialized yet so free_fs_info() is rendered useless.
Fix this by initializing fs_info pointer and fs_info fields before any
allocations happen.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
btrfs_parse_early_options() can fail due to error while scanning devices
(-o device= option), but still strdup() subvol_name string:
mount -o subvol=SUBV,device=BAD_DEVICE <dev> <mnt>
So free subvol_name string on error.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Don't leak subvol_name string in case multiple subvol= options are
given. "The lastest option is effective" behavior (consistent with
subvolid= and subvolrootid= options) is preserved.
Signed-off-by: Ilya Dryomov <idryomov@gmail.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>
If we fail to reserve space in the transaction during truncate, we can
error out with a NULL trans handle. The cleanup code needs an extra
check to make sure we aren't trying to use the bad handle.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
On error path 'tree_root' is treed in 'free_fs_info()'.
No need to free it explicitely. Noticed by SLUB in debug mode:
Complete reproducer under usermode linux (discovered on real
machine):
bdev=/dev/ubda
btr_root=/btr
/mkfs.btrfs $bdev
mount $bdev $btr_root
mkdir $btr_root/subvols/
cd $btr_root/subvols/
/btrfs su cr foo
/btrfs su cr bar
mount $bdev -osubvol=subvols/foo $btr_root/subvols/bar
umount $btr_root/subvols/bar
which gives
device fsid 4d55aa28-45b1-474b-b4ec-da912322195e devid 1 transid 7 /dev/ubda
=============================================================================
BUG kmalloc-2048: Object already free
-----------------------------------------------------------------------------
INFO: Allocated in btrfs_mount+0x389/0x7f0 age=0 cpu=0 pid=277
INFO: Freed in btrfs_mount+0x51c/0x7f0 age=0 cpu=0 pid=277
INFO: Slab 0x0000000062886200 objects=15 used=9 fp=0x0000000070b4d2d0 flags=0x4081
INFO: Object 0x0000000070b4d2d0 @offset=21200 fp=0x0000000070b4a968
...
Call Trace:
70b31948: [<6008c522>] print_trailer+0xe2/0x130
70b31978: [<6008c5aa>] object_err+0x3a/0x50
70b319a8: [<6008e242>] free_debug_processing+0x142/0x2a0
70b319e0: [<600ebf6f>] btrfs_mount+0x55f/0x7f0
70b319f8: [<6008e5c1>] __slab_free+0x221/0x2d0
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Cc: Arne Jansen <sensille@gmx.net>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
During log replay, can commit the transaction before the fs_root
pointers are setup, so we have to make sure they are not null before
trying to use them.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
While we're allocating ram for a new transaction, we drop our spinlock.
When we get the lock back, we do check to see if a transaction started
while we slept, but we don't check to make sure it isn't blocked
because a commit has already started.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
In case we were able to map less than we wanted (length < PAGE_SIZE
clause is true) btrfs_bio is still allocated and we have to free it.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
