In trying to track down where we were leaking reserved space I noticed our
reserve extent tracepoints are a little off.  First we were saying that the
reserved space had been alloced in btrfs_reserve_extent, which isn't the case,
this needs to be triggered when we actually allocate the space when we run the
delayed ref.  We were also missing a few places where we should have been
tracing the btrfs_reserve_extent_free tracepoint.  With these in place I was
able to put together where we were leaking reserved space.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

If we abort a transaction we will do the tree log cleanup at unmount, but this
happens after we free up the block groups.  This makes all the leak detection
warnings go off because we think we've leaked space but in reality we just
haven't cleaned it up yet.  So instead do the block group cleanup stuff after
free'ing the fs roots so we don't get these warnings.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

On error we will wait and free the tree log at unmount without a transaction.
This means that the actual freeing of the blocks doesn't happen which means we
complain about space leaks on unmount.  So to fix this just skip the transaction
specific cleanup part of the tree log free'ing if we don't have a transaction
and that way we can free up our reserved space and our counters stay happy.
Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

The transactions should be cleaning up their reservations on failure, this just
causes us to have warnings on unmount because we go negative by free'ing
reservations that have already been free'ed.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Structures of the types tree_mod_elem and qgroup_update are allocated
during transaction commit but were not being released if the call to
btrfs_run_delayed_items() returned an error.

Stack trace reported by kmemleak:

unreferenced object 0xffff880679f0b398 (size 128):
  comm "umount", pid 21508, jiffies 4295967793 (age 36718.112s)
  hex dump (first 32 bytes):
    60 b5 f0 79 06 88 ff ff 00 00 00 00 00 00 00 00  `..y............
    00 00 00 00 00 00 00 00 50 1c 00 00 00 00 00 00  ........P.......
  backtrace:
    [<ffffffff81742d26>] kmemleak_alloc+0x26/0x50
    [<ffffffff811889c2>] kmem_cache_alloc_trace+0x112/0x200
    [<ffffffffa046f2d3>] tree_mod_log_insert_key.constprop.45+0x93/0x150 [btrfs]
    [<ffffffffa04720f9>] __btrfs_cow_block+0x299/0x4f0 [btrfs]
    [<ffffffffa0472510>] btrfs_cow_block+0x120/0x1f0 [btrfs]
    [<ffffffffa0476679>] btrfs_search_slot+0x449/0x930 [btrfs]
    [<ffffffffa048eecf>] btrfs_lookup_inode+0x2f/0xa0 [btrfs]
    [<ffffffffa04eb49c>] __btrfs_update_delayed_inode+0x1c/0x1d0 [btrfs]
    [<ffffffffa04eb9e2>] __btrfs_run_delayed_items+0x162/0x1e0 [btrfs]
    [<ffffffffa04eba63>] btrfs_delayed_inode_exit+0x3/0x20 [btrfs]
    [<ffffffffa0499c63>] btrfs_commit_transaction+0x203/0xa50 [btrfs]
    [<ffffffffa046b519>] btrfs_sync_fs+0x69/0x110 [btrfs]
    [<ffffffff811cb210>] __sync_filesystem+0x30/0x60
    [<ffffffff811cb2bb>] sync_filesystem+0x4b/0x70
    [<ffffffff8119ce7b>] generic_shutdown_super+0x3b/0xf0
    [<ffffffff8119cfc6>] kill_anon_super+0x16/0x30
unreferenced object 0xffff880677e0dd88 (size 32):
  comm "umount", pid 21508, jiffies 4295967793 (age 36718.112s)
  hex dump (first 32 bytes):
    78 75 11 a9 06 88 ff ff 00 c0 e0 77 06 88 ff ff  xu.........w....
    40 c3 a2 70 06 88 ff ff 00 00 00 00 00 00 00 00  @..p............
  backtrace:
    [<ffffffff81742d26>] kmemleak_alloc+0x26/0x50
    [<ffffffff811889c2>] kmem_cache_alloc_trace+0x112/0x200
    [<ffffffffa04fa54f>] btrfs_qgroup_record_ref+0xf/0x90 [btrfs]
    [<ffffffffa04e1914>] btrfs_add_delayed_tree_ref+0xf4/0x170 [btrfs]
    [<ffffffffa048518a>] btrfs_free_tree_block+0x9a/0x220 [btrfs]
    [<ffffffffa0472163>] __btrfs_cow_block+0x303/0x4f0 [btrfs]
    [<ffffffffa0472510>] btrfs_cow_block+0x120/0x1f0 [btrfs]
    [<ffffffffa0476679>] btrfs_search_slot+0x449/0x930 [btrfs]
    [<ffffffffa048eecf>] btrfs_lookup_inode+0x2f/0xa0 [btrfs]
    [<ffffffffa04eb49c>] __btrfs_update_delayed_inode+0x1c/0x1d0 [btrfs]
    [<ffffffffa04eb9e2>] __btrfs_run_delayed_items+0x162/0x1e0 [btrfs]
    [<ffffffffa04eba63>] btrfs_delayed_inode_exit+0x3/0x20 [btrfs]
    [<ffffffffa0499c63>] btrfs_commit_transaction+0x203/0xa50 [btrfs]
    [<ffffffffa046b519>] btrfs_sync_fs+0x69/0x110 [btrfs]
    [<ffffffff811cb210>] __sync_filesystem+0x30/0x60
    [<ffffffff811cb2bb>] sync_filesystem+0x4b/0x70
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Replace progresses strictly from lower to higher offsets, and the
progress is tracked in chunks, by storing the physical offset of the
dev_extent which is being copied in the cursor_left field of
btrfs_dev_replace_item.  When we are done copying the chunk,
left_cursor is updated to point one byte past the dev_extent, so that
on resume we can skip the dev_extents that have already been copied.

There is a major bug (which goes all the way back to the inception of
dev-replace in 3.8) in the way left_cursor is bumped: the bump is done
unconditionally, without any regard to the scrub_chunk return value.
On suspend (and also on any kind of error) scrub_chunk returns early,
i.e. without completing the copy.  This leads to us skipping the chunk
that hasn't been fully copied yet when resuming.

Fix this by doing the cursor_left update only if scrub_chunk ret is 0.
(On suspend scrub_chunk returns with -ECANCELED, so this fix covers
both suspend and error cases.)

Cc: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Currently the hash value used for adding an inode to the VFS's inode
hash table consists of the plain inode number, which is a 64 bits
integer. This results in hash table buckets (hlist_head lists) with
too many elements for at least 2 important scenarios:

1) When we have many subvolumes. Each subvolume has its own btree
   where its files and directories are added to, and each has its
   own objectid (inode number) namespace. This means that if we have
   N subvolumes, and all have inode number X associated to a file or
   directory, the corresponding inodes all map to the same hash table
   entry, resulting in a bucket (hlist_head list) with N elements;

2) On 32 bits machines. Th VFS hash values are unsigned longs, which
   are 32 bits wide on 32 bits machines, and the inode (objectid)
   numbers are 64 bits unsigned integers. We simply cast the inode
   numbers to hash values, which means that for all inodes with the
   same 32 bits lower half, the same hash bucket is used for all of
   them. For example, all inodes with a number (objectid) between
   0x0000_0000_ffff_ffff and 0xffff_ffff_ffff_ffff will end up in
   the same hash table bucket.

This change ensures the inode's hash value depends both on the
objectid (inode number) and its subvolume's (btree root) objectid.
For 32 bits machines, this change gives better entropy by making
the hash value depend on both the upper and lower 32 bits of the
64 bits hash previously computed.
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

In tree-log.c:btrfs_log_inode(), we keep calling btrfs_search_forward()
until it returns a key whose objectid is higher than our inode or until
the key's type is higher than our maximum allowed type.

At the end of the loop, we increment our mininum search key's objectid
and type regardless of our desired target objectid and maximum desired
type, which causes another loop iteration that will call again
btrfs_search_forward() just to figure out we've gone beyond our maximum
key and exit the loop. Therefore while incrementing our minimum key,
don't do it blindly and exit the loop immiediately if the next search
key's objectid or type is beyond what we seek.

Also after incrementing the type, set the key's offset to 0, which was
missing and could make us loose some of the inode's items.
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

It is not used for anything.
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

As we're hold a ref on looking up the extent map, we need to drop the ref
before returning to callers.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

The performance was slowed down sometimes when we ran sysbench to measure
the performance of the sequential buffered write by 2 or more threads.

It was because the write order of the test threads might be confused
by the task scheduler, and the coming write would be beyond the end of
the file, in this case, we need insert dummy file extents and create
a hole for the area we skip. But in order to avoid the ongoing ordered
extents which are in the area, we need wait for them. Unfortunately,
the current code doesn't check if there are ordered extents in the area
or not, try to find and flush the dirty pages directly, but in fact,
there is no dirty page in that area, this step of the current code is
unnecessary, and just wastes time. Sometimes, it would increase
the contention of some locks, and makes the performance slow down suddenly.

So we remove the ordered extent flush function before the check, and flush
the dirty pages and wait for the ordered extents only when we find them.

According to my test, we got 1-2 times of the performance regression when
we ran the test by 10 times before applying this patch. After applying
this patch, the regression went away.

Test Environment:
 CPU:		1CPU * 4Cores
 Memory:	6GB
 Partition:	20GB

Test Command:
 # sysbench --test=fileio --file-total-size=16G --file-test-mode=seqwr \
 > --num-threads=512 --file-block-size=16384 --max-time=60 --max-requests=0 run
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

When we did space balance and snapshot creation at the same time, we might
meet the following oops:
 kernel BUG at fs/btrfs/inode.c:3038!
 [SNIP]
 Call Trace:
 [<ffffffffa0411ec7>] btrfs_orphan_cleanup+0x293/0x407 [btrfs]
 [<ffffffffa042dc45>] btrfs_mksubvol.isra.28+0x259/0x373 [btrfs]
 [<ffffffffa042de85>] btrfs_ioctl_snap_create_transid+0x126/0x156 [btrfs]
 [<ffffffffa042dff1>] btrfs_ioctl_snap_create_v2+0xd0/0x121 [btrfs]
 [<ffffffffa0430b2c>] btrfs_ioctl+0x414/0x1854 [btrfs]
 [<ffffffff813b60b7>] ? __do_page_fault+0x305/0x379
 [<ffffffff811215a9>] vfs_ioctl+0x1d/0x39
 [<ffffffff81121d7c>] do_vfs_ioctl+0x32d/0x3e2
 [<ffffffff81057fe7>] ? finish_task_switch+0x80/0xb8
 [<ffffffff81121e88>] SyS_ioctl+0x57/0x83
 [<ffffffff813b39ff>] ? do_device_not_available+0x12/0x14
 [<ffffffff813b99c2>] system_call_fastpath+0x16/0x1b
 [SNIP]
 RIP  [<ffffffffa040da40>] btrfs_orphan_add+0xc3/0x126 [btrfs]

The reason of the problem is that the relocation root creation stole
the reserved space, which was reserved for orphan item deletion.

There are several ways to fix this problem, one is to increasing
the reserved space size of the space balace, and then we can use
that space to create the relocation tree for each fs/file trees.
But it is hard to calculate the suitable size because we doesn't
know how many fs/file trees we need relocate.

We fixed this problem by reserving the space for relocation root creation
actively since the space it need is very small (one tree block, used for
root node copy), then we use that reserved space to create the
relocation tree. If we don't reserve space for relocation tree creation,
we will use the reserved space of the balance.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Remove unused parameter, 'eb'. Unused since introduction in
5f39d397

Updated to be rebased against current upstream and correct diff supplied this time!
Signed-off-by: NRoss Kirk <ross.kirk@gmail.com>
Reviewed-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

I was noticing the slab redzone stuff going off every once and a while during
transaction aborts.  This was caused by two things

1) We would walk the pending snapshots and set their error to -ECANCELED.  We
don't need to do this, the snapshot stuff waits for a transaction commit and if
there is a problem we just free our pending snapshot object and exit.  Doing
this was causing us to touch the pending snapshot object after the thing had
already been freed.

2) We were freeing the transaction manually with wanton disregard for it's
use_count reference counter.  To fix this I cleaned up the transaction freeing
loop to either wait for the transaction commit to finish if it was in the middle
of that (since it will be cleaned and freed up there) or to do the cleanup
oursevles.

I also moved the global "kill all things dirty everywhere" stuff outside of the
transaction cleanup loop since that only needs to be done once.  With this patch
I'm no longer seeing slab corruption because of use after frees.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Noticed this when forcing errors to happen during delayed ref running.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

During transaction cleanup after an abort we are just removing roots from the
ordered roots list which is incorrect.  We have a BUG_ON() to make sure that the
root is still part of the ordered roots list when we put our ordered extent
which we were tripping in this case.  So do like we do everywhere else and just
move it to the tail of the ordered roots list and allow the normal cleanup to
take care of stuff.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

If we abort not during a transaction commit we won't clean up anything until we
unmount.  Unfortunately if we abort in the middle of writing out an ordered
extent we won't clean it up and if somebody is waiting on that ordered extent
they will wait forever.  To fix this just make the transaction kthread call the
cleanup transaction stuff if it notices theres an error, and make
btrfs_end_transaction wake up the transaction kthread if there is an error.
Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

I've been testing our error paths and I was tripping the BUG_ON() in
drop_outstanding_extent because our outstanding_extents is 0 for space cache
inodes.  This is because we don't reserve metadata space for these inodes since
we depend on the global block reserve for our space.  To fix this we need to
make sure the DO_ACCOUNTING stuff doesn't actually call release_metadata for
space cache inodes.  With this patch I'm no longer panicing.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

If we abort a transaction in the middle of a commit we weren't undoing the
intwrite locking.  This patch fixes that problem.
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

A user reported a problem where they were getting csum errors when running a
balance and running systemd's journal.  This is because systemd is awesome and
fallocate()'s its log space and writes into it.  Unfortunately we assume that
when we read in all the csums for an extent that they are sequential starting at
the bytenr we care about.  This obviously isn't the case for prealloc extents,
where we could have written to the middle of the prealloc extent only, which
means the csum would be for the bytenr in the middle of our range and not the
front of our range.  Fix this by offsetting the new bytenr we are logging to
based on the original bytenr the csum was for.  With this patch I no longer see
the csum errors I was seeing.  Thanks,

Cc: stable@vger.kernel.org
Reported-by: NChris Murphy <lists@colorremedies.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

In extent-tree.c:btrfs_write_dirty_block_groups(), if the call to
write_one_cache_group() failed, we would return without putting
the block group first.
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Currently the fs sync function (super.c:btrfs_sync_fs()) doesn't
wait for delayed work to finish before returning success to the
caller. This change fixes this, ensuring that there's no data loss
if a power failure happens right after fs sync returns success to
the caller and before the next commit happens.

Steps to reproduce the data loss issue:

$ mkfs.btrfs -f /dev/sdb3
$ mount /dev/sdb3 /mnt/btrfs
$ perl -e '$d = ("\x41" x 6001); open($f,">","/mnt/btrfs/foobar"); print $f $d; close($f);' && btrfs fi sync /mnt/btrfs

Right after the btrfs fi sync command (a second or 2 for example), power
off the machine and reboot it. The file will be empty, as it can be verified
after mounting the filesystem and through btrfs-debug-tree:

$ btrfs-debug-tree /dev/sdb3 | egrep '\(257 INODE_ITEM 0\) itemoff' -B 3 -A 8
        item 3 key (256 DIR_INDEX 2) itemoff 3751 itemsize 36
                location key (257 INODE_ITEM 0) type FILE
                namelen 6 datalen 0 name: foobar
        item 4 key (257 INODE_ITEM 0) itemoff 3591 itemsize 160
                inode generation 7 transid 7 size 0 block group 0 mode 100644 links 1
        item 5 key (257 INODE_REF 256) itemoff 3575 itemsize 16
                inode ref index 2 namelen 6 name: foobar
checksum tree key (CSUM_TREE ROOT_ITEM 0)
leaf 29429760 items 0 free space 3995 generation 7 owner 7
fs uuid 6192815c-af2a-4b75-b3db-a959ffb6166e
chunk uuid b529c44b-938c-4d3d-910a-013b4700bcae
uuid tree key (UUID_TREE ROOT_ITEM 0)

After this patch, the data loss no longer happens after a power failure and
btrfs-debug-tree shows:

$ btrfs-debug-tree /dev/sdb3 | egrep '\(257 INODE_ITEM 0\) itemoff' -B 3 -A 8
	item 3 key (256 DIR_INDEX 2) itemoff 3751 itemsize 36
		location key (257 INODE_ITEM 0) type FILE
		namelen 6 datalen 0 name: foobar
	item 4 key (257 INODE_ITEM 0) itemoff 3591 itemsize 160
		inode generation 6 transid 6 size 6001 block group 0 mode 100644 links 1
	item 5 key (257 INODE_REF 256) itemoff 3575 itemsize 16
		inode ref index 2 namelen 6 name: foobar
	item 6 key (257 EXTENT_DATA 0) itemoff 3522 itemsize 53
		extent data disk byte 12845056 nr 8192
		extent data offset 0 nr 8192 ram 8192
		extent compression 0
checksum tree key (CSUM_TREE ROOT_ITEM 0)
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Reviewed-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

In inode.c:btrfs_orphan_add() if we failed to insert the orphan
item, we would return without decrementing the orphan count that
we just incremented before attempting the insertion, leaving the
orphan inode count wrong.

In inode.c:btrfs_orphan_del(), we were decrementing the inode
orphan count if the bit BTRFS_INODE_ORPHAN_META_RESERVED was set,
which is logically wrong because it should be decremented if the
bit BTRFS_INODE_HAS_ORPHAN_ITEM was set - after all we increment
the count when we set the bit BTRFS_INODE_HAS_ORPHAN_ITEM elsewhere.
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Similar to ocfs2, btrfs also supports that extents can be shared by
different inodes, and there are some userspace tools requesting
for this kind of 'space shared infomation'.[1]

ocfs2 uses flag FIEMAP_EXTENT_SHARED, so does btrfs.

[1]: http://thr3ads.net/ocfs2-devel/2010/09/489052-PATCH-3-3-shared-du-using-fiemap-to-figure-up-the-shared-extents-per-file-and-the-footprint-inReviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Not used for anything, and removing it avoids caller's need to
allocate a path structure.
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

We're doing a unnecessary extra lookup of the ino cache's
inode when we already have it (and holding a reference)
during the process of saving the ino cache contents to disk.
Therefore remove this extra lookup.
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

While running some snashot aware defrag tests I noticed I was panicing every
once and a while in key_search.  This is because of the optimization that says
if we find a key at slot 0 it will be at slot 0 all the way down the rest of the
tree.  This isn't the case for btrfs_search_old_slot since it will likely replay
changes to a buffer if something has changed since we took our sequence number.
So short circuit this optimization by setting prev_cmp to -1 every time we call
key_search so we will do our normal binary search.  With this patch I am no
longer seeing the panics I was seeing before.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

While looking at somebodys corruption I became completely convinced that
btrfs_split_item was broken, so I wrote this test to verify that it was working
as it was supposed to.  Thankfully it appears to be working as intended, so just
add this test to make sure nobody breaks it in the future.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Remove unused eb parameter from btrfs_item_nr
Signed-off-by: NRoss Kirk <ross.kirk@gmail.com>
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

It is not necessary to store the NULL byte in a symlink inline file
extent. There's currently no code that requires the NULL byte to be
present in the extent. This change also doesn't break file format
compatibility nor the send/receive feature.

The VFS also doesn't need the NULL byte to be present in the extent,
as it reads up to inode->i_size bytes (which already excluded the NULL
byte) and sets the NULL byte for us (in fs/namei.c:page_getlink()).

So with this change we save 1 byte per symlink file extent (which is
always inlined in the btree leaf) without losing backward and forward
compatibility.
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

The fact that btrfs_root_refs() returned 0 for the tree_root caused
bugs in the past, therefore it is set to 1 with this patch and
(hopefully) all affected code is adapted to this change.

I verified this change by temporarily adding WARN_ON() checks
everywhere where btrfs_root_refs() is used, checking whether the
logic of the code is changed by btrfs_root_refs() returning 1
instead of 0 for root->root_key.objectid == BTRFS_ROOT_TREE_OBJECTID.
With these added checks, I ran the xfstests './check -g auto'.

The two roots chunk_root and log_root_tree that are only referenced
by the superblock and the log_roots below the log_root_tree still
have btrfs_root_refs() == 0, only the tree_root is changed.
Signed-off-by: NStefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Pull MIPS fixes from Ralf Baechle:
 "Three fixes across arch/mips with the most complex one being the GIC
  interrupt fix - at nine lines still not monster.  I'm confident this
  are the final MIPS patches even if there should go for an rc8"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: ralink: fix return value check in rt_timer_probe()
  MIPS: malta: Fix GIC interrupt offsets
  MIPS: Perf: Fix 74K cache map

Negative message lengths make no sense -- so don't do negative queue
lenghts or identifier counts. Prevent them from getting negative.

Also change the underlying data types to be unsigned to avoid hairy
surprises with sign extensions in cases where those variables get
evaluated in unsigned expressions with bigger data types, e.g size_t.

In case a user still wants to have "unlimited" sizes she could just use
INT_MAX instead.
Signed-off-by: NMathias Krause <minipli@googlemail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull ARM kallsyms fix from Rusty Russell:
 "Last minute perf unbreakage for ARM modules; spent a day in
  linux-next"

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  scripts/kallsyms: filter symbols not in kernel address space

A vmalloc fault needs to sync up PGD/PTE entry from init_mm to current
task's "active_mm".  ARC vmalloc fault handler however was using mm.

A vmalloc fault for non user task context (actually pre-userland, from
init thread's open for /dev/console) caused the handler to deref NULL mm
(for mm->pgd)

The reasons it worked so far is amazing:

1. By default (!SMP), vmalloc fault handler uses a cached value of PGD.
   In SMP that MMU register is repurposed hence need for mm pointer deref.

2. In pre-3.12 SMP kernel, the problem triggering vmalloc didn't exist in
   pre-userland code path - it was introduced with commit 20bafb3d
   "n_tty: Move buffers into n_tty_data"
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: Noam Camus <noamc@ezchip.com>
Cc: stable@vger.kernel.org    #3.10 and 3.11
Cc: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch uses CONFIG_PAGE_OFFSET to filter symbols which
are not in kernel address space because these symbols are
generally for generating code purpose and can't be run at
kernel mode, so we needn't keep them in /proc/kallsyms.

For example, on ARM there are some symbols which may be
linked in relocatable code section, then perf can't parse
symbols any more from /proc/kallsyms, this patch fixes the
problem (introduced b9b32bf7)

Cc: Russell King <linux@arm.linux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Michal Marek <mmarek@suse.cz>
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: stable@vger.kernel.org

Pull perf fixes from Ingo Molnar:
 "Two fixes:

   - Fix 'NMI handler took too long to run' false positives

     [ Genuine NMI overhead speedups will come for v3.13, this commit
       only fixes a measurement bug ]

   - Fix perf ring-buffer missed barrier causing (rare) ring-buffer data
     corruption on ppc64"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86: Fix NMI measurements
  perf: Fix perf ring buffer memory ordering

Pull USB fixes from Greg KH:
 "Here is a set of patches that revert all of the changes done to the
  pl2303 USB serial driver in the 3.12-rc timeframe, as it turns out
  they break some devices that work just fine on 3.11.  As it's not a
  good idea to break working systems, drop them all and they will be
  reworked for future kernel versions such that there is no breakage.

  I've also included a MAINTAINERS update for the USB serial subsystem
  and a new device id for the ftdi_sio driver as well"

* tag 'usb-3.12-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  USB: serial: ftdi_sio: add id for Z3X Box device
  USB: Maintainers change for usb serial drivers
  Revert "USB: pl2303: restrict the divisor based baud rate encoding method to the "HX" chip type"
  Revert "usb: pl2303: fix+improve the divsor based baud rate encoding method"
  Revert "usb: pl2303: do not round to the next nearest standard baud rate for the divisor based baud rate encoding method"
  Revert "usb: pl2303: remove 500000 baud from the list of standard baud rates"
  Revert "usb: pl2303: move the two baud rate encoding methods to separate functions"
  Revert "usb: pl2303: increase the allowed baud rate range for the divisor based encoding method"
  Revert "usb: pl2303: also use the divisor based baud rate encoding method for baud rates < 115200 with HX chips"
  Revert "usb: pl2303: add two comments concerning the supported baud rates with HX chips"
  Revert "pl2303: simplify the else-if contruct for type_1 chips in pl2303_startup()"
  Revert "pl2303: improve the chip type information output on startup"
  Revert "pl2303: improve the chip type detection/distinction"
  Revert "USB: pl2303: distinguish between original and cloned HX chips"

Pull more sound fixes from Takashi Iwai:
 "The fixes for random bugs that have been reported lately in the game:
  a few fixes in ASoC dpam and wm_hubs bugs spotted by Coverity, a
  one-liner HD-audio fixup, and a fix for Oops with DPCM.

  They are not so critically urgent bugs, but all small and safe"

* tag 'sound-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: fix oops in snd_pcm_info() caused by ASoC DPCM
  ASoC: wm_hubs: Add missing break in hp_supply_event()
  ALSA: hda - Add a fixup for ASUS N76VZ
  ASoC: dapm: Return -ENOMEM in snd_soc_dapm_new_dai_widgets()
  ASoC: dapm: Fix source list debugfs outputs