linux.git/fs/btrfs/backref.c, branch v4.10

btrfs: remove root parameter from transaction commit/end routines

2016-12-06T15:07:00+00:00

Now we only use the root parameter to print the root objectid in
a tracepoint.  We can use the root parameter from the transaction
handle for that.  It's also used to join the transaction with
async commits, so we remove the comment that it's just for checking.

Signed-off-by: Jeff Mahoney 
Signed-off-by: David Sterba

btrfs: take an fs_info directly when the root is not used otherwise

2016-12-06T15:06:59+00:00

There are loads of functions in btrfs that accept a root parameter
but only use it to obtain an fs_info pointer.  Let's convert those to
just accept an fs_info pointer directly.

Signed-off-by: Jeff Mahoney 
Signed-off-by: David Sterba

btrfs: pull node/sector/stripe sizes out of root and into fs_info

2016-12-06T15:06:58+00:00

We track the node sizes per-root, but they never vary from the values
in the superblock.  This patch messes with the 80-column style a bit,
but subsequent patches to factor out root->fs_info into a convenience
variable fix it up again.

Signed-off-by: Jeff Mahoney 
Signed-off-by: David Sterba

btrfs: convert pr_* to btrfs_* where possible

2016-09-26T17:37:04+00:00

For many printks, we want to know which file system issued the message.

This patch converts most pr_* calls to use the btrfs_* versions instead.
In some cases, this means adding plumbing to allow call sites access to
an fs_info pointer.

fs/btrfs/check-integrity.c is left alone for another day.

Signed-off-by: Jeff Mahoney 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: unsplit printed strings

2016-09-26T16:08:44+00:00

CodingStyle chapter 2:
"[...] never break user-visible strings such as printk messages,
because that breaks the ability to grep for them."

This patch unsplits user-visible strings.

Signed-off-by: Jeff Mahoney 
Signed-off-by: David Sterba

btrfs: fix check_shared for fiemap ioctl

2016-09-26T15:59:49+00:00

Only in the case of different root_id or different object_id, check_shared
identified extent as the shared. However, If a extent was referred by
different offset of same file, it should also be identified as shared.
In addition, check_shared's loop scale is at least n^3, so if a extent
has too many references, even causes soft hang up.

First, add all delayed_ref to the ref_tree and calculate the unqiue_refs,
if the unique_refs is greater than one, return BACKREF_FOUND_SHARED.
Then individually add the on-disk reference(inline/keyed) to the ref_tree
and calculate the unique_refs of the ref_tree to check if the unique_refs
is greater than one.Because once there are two references to return
SHARED, so the time complexity is close to the constant.

Reported-by: Tsutomu Itoh 
Signed-off-by: Lu Fengqi 
Signed-off-by: David Sterba

btrfs: backref: Fix soft lockup in __merge_refs function

2016-08-25T10:58:16+00:00

When over 1000 file extents refers to one extent, find_parent_nodes()
will be obviously slow, due to the O(n^2)~O(n^3) loops inside
__merge_refs().

The following ftrace shows the cubic growth of execution time:

256 refs
 5) + 91.768 us   |  __add_keyed_refs.isra.12 [btrfs]();
 5)   1.447 us    |  __add_missing_keys.isra.13 [btrfs]();
 5) ! 114.544 us  |  __merge_refs [btrfs]();
 5) ! 136.399 us  |  __merge_refs [btrfs]();

512 refs
 6) ! 279.859 us  |  __add_keyed_refs.isra.12 [btrfs]();
 6)   3.164 us    |  __add_missing_keys.isra.13 [btrfs]();
 6) ! 442.498 us  |  __merge_refs [btrfs]();
 6) # 2091.073 us |  __merge_refs [btrfs]();

and 1024 refs
 7) ! 368.683 us  |  __add_keyed_refs.isra.12 [btrfs]();
 7)   4.810 us    |  __add_missing_keys.isra.13 [btrfs]();
 7) # 2043.428 us |  __merge_refs [btrfs]();
 7) * 18964.23 us |  __merge_refs [btrfs]();

And sort them into the following char:
(Unit: us)
------------------------------------------------------------------------
 Trace function        | 256 ref        | 512 refs      | 1024 refs    |
------------------------------------------------------------------------
 __add_keyed_refs      | 91             | 249           | 368          |
 __add_missing_keys    | 1              | 3             | 4            |
 __merge_refs 1st call | 114            | 442           | 2043         |
 __merge_refs 2nd call | 136            | 2091          | 18964        |
------------------------------------------------------------------------

We can see the that __add_keyed_refs() grows almost in linear behavior.
And __add_missing_keys() in this case doesn't change much or takes much
time.

While for the 1st __merge_refs() it's square growth
for the 2nd __merge_refs() call it's cubic growth.

It's no doubt that merge_refs() will take a long long time to execute if
the number of refs continues its grows.

So add a cond_resced() into the loop of __merge_refs().

Although this will solve the problem of soft lockup, we need to use the
new rb_tree based structure introduced by Lu Fengqi to really solve the
long execution time.

Signed-off-by: Qu Wenruo 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba 
Signed-off-by: Chris Mason

btrfs: tests, use BTRFS_FS_STATE_DUMMY_FS_INFO instead of dummy root

2016-07-26T11:54:19+00:00

Now that we have a dummy fs_info associated with each test that
uses a root, we don't need the DUMMY_ROOT bit anymore.  This lets
us make choices without needing an actual root like in e.g.
btrfs_find_create_tree_block.

Signed-off-by: Jeff Mahoney 
Signed-off-by: David Sterba

btrfs: Fix slab accounting flags

2016-07-26T11:52:25+00:00

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 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

Merge branch 'cleanups-4.7' into for-chris-4.7-20160525

2016-05-25T20:51:03+00:00