btree_releasepage is a callback and can be passed unknown gfp flags and then
they may end up in kmem_cache_alloc called from alloc_extent_state, slab
allocator will BUG_ON when there is HIGHMEM or DMA32 flag set.

This may happen when btrfs is mounted from a loop device, which masks out
__GFP_IO flag. The check in try_release_extent_state

3399                 if ((mask & GFP_NOFS) == GFP_NOFS)
3400                         mask = GFP_NOFS;

will not work and passes unfiltered flags further resulting in crash at
mm/slab.c:2963

 [<000000000024ae4c>] cache_alloc_refill+0x3b4/0x5c8
 [<000000000024c810>] kmem_cache_alloc+0x204/0x294
 [<00000000001fd3c2>] mempool_alloc+0x52/0x170
 [<000003c000ced0b0>] alloc_extent_state+0x40/0xd4 [btrfs]
 [<000003c000cee5ae>] __clear_extent_bit+0x38a/0x4cc [btrfs]
 [<000003c000cee78c>] try_release_extent_state+0x9c/0xd4 [btrfs]
 [<000003c000cc4c66>] btree_releasepage+0x7e/0xd0 [btrfs]
 [<0000000000210d84>] shrink_page_list+0x6a0/0x724
 [<0000000000211394>] shrink_inactive_list+0x230/0x578
 [<0000000000211bb8>] shrink_list+0x6c/0x120
 [<0000000000211e4e>] shrink_zone+0x1e2/0x228
 [<0000000000211f24>] shrink_zones+0x90/0x254
 [<0000000000213410>] do_try_to_free_pages+0xac/0x420
 [<0000000000213ae0>] try_to_free_pages+0x13c/0x1b0
 [<0000000000204e6c>] __alloc_pages_nodemask+0x5b4/0x9a8
 [<00000000001fb04a>] grab_cache_page_write_begin+0x7e/0xe8
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Implement an ioctl for canceling restriper.  Currently we wait until
relocation of the current block group is finished, in future this can be
done by triggering a commit.  Balance item is deleted and no memory
about the interrupted balance is kept.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Implement an ioctl for pausing restriper.  This pauses the relocation,
but balance is still considered to be "in progress": balance item is
not deleted, other volume operations cannot be started, etc.  If paused
in the middle of profile changing operation we will continue making
allocations with the target profile.

Add a hook to close_ctree() to pause restriper and free its data
structures on unmount.  (It's safe to unmount when restriper is in
"paused" state, we will resume with the same parameters on the next
mount)
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

On mount, if balance item is found, resume balance in a separate
kernel thread.

Try to be smart to continue roughly where previous balance (or convert)
was interrupted.  For chunk types that were being converted to some
profile we turn on soft convert, in case of a simple balance we turn on
usage filter and relocate only less-than-90%-full chunks of that type.
These are just heuristics but they help quite a bit, and can be improved
in future.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Add basic restriper infrastructure: extended balancing ioctl and all
related ioctl data structures, add data structure for tracking
restriper's state to fs_info, etc.  The semantics of the old balancing
ioctl are fully preserved.

Explicitly disallow any volume operations when balance is in progress.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

{data,metadata,system}_alloc_profile fields have been unused for a long
time now.  Get rid of them.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

This patch adds a lightweight sync migrate operation MIGRATE_SYNC_LIGHT
mode that avoids writing back pages to backing storage.  Async compaction
maps to MIGRATE_ASYNC while sync compaction maps to MIGRATE_SYNC_LIGHT.
For other migrate_pages users such as memory hotplug, MIGRATE_SYNC is
used.

This avoids sync compaction stalling for an excessive length of time,
particularly when copying files to a USB stick where there might be a
large number of dirty pages backed by a filesystem that does not support
->writepages.

[aarcange@redhat.com: This patch is heavily based on Andrea's work]
[akpm@linux-foundation.org: fix fs/nfs/write.c build]
[akpm@linux-foundation.org: fix fs/btrfs/disk-io.c build]
Signed-off-by: NMel Gorman <mgorman@suse.de>
Reviewed-by: NRik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andy Isaacson <adi@hexapodia.org>
Cc: Nai Xia <nai.xia@gmail.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Asynchronous compaction is used when allocating transparent hugepages to
avoid blocking for long periods of time.  Due to reports of stalling,
there was a debate on disabling synchronous compaction but this severely
impacted allocation success rates.  Part of the reason was that many dirty
pages are skipped in asynchronous compaction by the following check;

	if (PageDirty(page) && !sync &&
		mapping->a_ops->migratepage != migrate_page)
			rc = -EBUSY;

This skips over all mapping aops using buffer_migrate_page() even though
it is possible to migrate some of these pages without blocking.  This
patch updates the ->migratepage callback with a "sync" parameter.  It is
the responsibility of the callback to fail gracefully if migration would
block.
Signed-off-by: NMel Gorman <mgorman@suse.de>
Reviewed-by: NRik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andy Isaacson <adi@hexapodia.org>
Cc: Nai Xia <nai.xia@gmail.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The correct lock order is uuid_mutex -> volume_mutex -> chunk_mutex,
but when we mount a filesystem which has backing seed devices, we have
this lock chain:

    open_ctree()
        lock(chunk_mutex);
        read_chunk_tree();
            read_one_dev();
                open_seed_devices();
                    lock(uuid_mutex);

and then we hit a lockdep splat.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>

now that we don't need it for sget() anymore...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

the latter can be obtained from the former (by looking as ->tree_root)
just as cheaply as we currently are doing the other way round.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... all the way up into btrfs_mount().
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

It returns either ERR_PTR(-ve) or sb->s_fs_info.  The latter can
be found by caller just as well, TYVM, no need to return it.  Just
return -ve or 0...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

close_ctree() uses a weird mix of accesses to root->fs_info and
its value at the beginning of function stored in local variable.
Since ->fs_info *never* changes, let's just use the local variable
to avoid confusion.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

A new helper: btrfs_alloc_root(fs_info); allocates btrfs_root
and sets ->fs_info.  All places allocating the suckers converted
to it.  At that point we *never* reassign ->fs_info of btrfs_root;
it's set before anyone sees the address of newly allocated
struct btrfs_root and never assigned anywhere else.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

move assignments to ->fs_info in open_ctree() up, to the place
just after the original allocations.  Assignment for tree_root
becomes a no-op - we'd obtained fs_info from tree_root->fs_info
in the first place.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

lift assignment to callers of find_and_setup_root()
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

take assignment of ->fs_info to callers of __setup_root()
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We need fs_info and root to live until the moment when the victim
superblock leaves the list, so we need to postpone free_fs_info()
until after ->put_super().  The call is buried in close_ctree(),
though, so we need to lift it into the callers (including
btrfs_put_super()) first.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Add a for_cow parameter to add_delayed_*_ref and pass the appropriate value
from every call site. The for_cow parameter will later on be used to
determine if a ref will change anything with respect to qgroups.

Delayed refs coming from relocation are always counted as for_cow, as they
don't change subvol quota.

Also pass in the fs_info for later use.

btrfs_find_all_roots() will use this as an optimization, as changes that are
for_cow will not change anything with respect to which root points to a
certain leaf. Thus, we don't need to add the current sequence number to
those delayed refs.
Signed-off-by: NArne Jansen <sensille@gmx.net>
Signed-off-by: NJan Schmidt <list.btrfs@jan-o-sch.net>

This is the last part of the patch series. It modifies the btrfs
code to use the integrity check module if configured to do so
with the define BTRFS_FS_CHECK_INTEGRITY. If this define is not set,
the only effective change is that code is added that handles the
mount option to activate the integrity check. If the mount option is
set and the define BTRFS_FS_CHECK_INTEGRITY is not set, that code
complains in the log and the mount fails with EINVAL.

Add the mount option to activate the usage of the integrity check
code.
Add invocation of btrfs integrity check code init and cleanup
function on mount and umount, respectively.
Add hook to call btrfs integrity check code version of
submit_bh/submit_bio.
Signed-off-by: NStefan Behrens <sbehrens@giantdisaster.de>

Al pointed out we have some random problems with the way we account for
num_workers_starting in the async thread stuff.  First of all we need to make
sure to decrement num_workers_starting if we fail to start the worker, so make
__btrfs_start_workers do this.  Also fix __btrfs_start_workers so that it
doesn't call btrfs_stop_workers(), there is no point in stopping everybody if we
failed to create a worker.  Also check_pending_worker_creates needs to call
__btrfs_start_work in it's work function since it already increments
num_workers_starting.

People only start one worker at a time, so get rid of the num_workers argument
everywhere, and make btrfs_queue_worker a void since it will always succeed.
Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

There is no reason to export two functions for entering the
refrigerator.  Calling refrigerator() instead of try_to_freeze()
doesn't save anything noticeable or removes any race condition.

* Rename refrigerator() to __refrigerator() and make it return bool
  indicating whether it scheduled out for freezing.

* Update try_to_freeze() to return bool and relay the return value of
  __refrigerator() if freezing().

* Convert all refrigerator() users to try_to_freeze().

* Update documentation accordingly.

* While at it, add might_sleep() to try_to_freeze().
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Samuel Ortiz <samuel@sortiz.org>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: Christoph Hellwig <hch@infradead.org>

My previous patch introduced some u64 for failed_mirror variables, this one
makes it consistent again.
Signed-off-by: NJan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: NChris 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: NChris Mason <chris.mason@oracle.com>
Reported-by: NAlexandre Oliva <oliva@lsd.ic.unicamp.br>

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: NIlya 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: NIlya Dryomov <idryomov@gmail.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: NChris Mason <chris.mason@oracle.com>

If we don't stop them, they linger around corrupting
memory by using pointers to freed things.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

The scrub readahead branch brought in a new error handling hook,
but it was leaking extent_buffer references.
Signed-off-by: NChris 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: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This takes some of the free space in the btrfs super block
to record information about most of the roots in the last four
commits.

It also adds a -o recovery to use the root history log when
we're not able to read the tree of tree roots, the extent
tree root, the device tree root or the csum root.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

fs_info has now ~9kb, more than fits into one page. This will cause
mount failure when memory is too fragmented. Top space consumers are
super block structures super_copy and super_for_commit, ~2.8kb each.
Allocate them dynamically. fs_info will be ~3.5kb. (measured on x86_64)

Add a wrapper for freeing fs_info and all of it's dynamically allocated
members.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>

write_cache_pages tries to build up a large bio to stuff down the pipe.
But if it needs to wait for a page lock, it needs to make sure and send
down any pending writes so we don't deadlock with anyone who has the
page lock and is waiting for writeback of things inside the bio.

Dave Sterba triggered this as a deadlock between the autodefrag code and
the extent write_cache_pages
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Replace remaining direct i_nlink updates with a new set_nlink()
updater function.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Tested-by: NToshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

One of the things that kills us is the fact that our ENOSPC reservations are
horribly over the top in most normal cases.  There isn't too much that can be
done about this because when we are completely full we really need them to work
like this so we don't under reserve.  However if there is plenty of unallocated
chunks on the disk we can use that to gauge how much we can overcommit.  So this
patch adds chunk free space accounting so we always know how much unallocated
space we have.  Then if we fail to make a reservation within our allocated
space, check to see if we can overcommit.  In the normal flushing case (like
with delalloc metadata reservations) we'll take the free space and divide it by
2 if our metadata profile is setup for DUP or any of those, and then divide it
by 8 to make sure we don't overcommit too much.  Then if we're in a non-flushing
case (we really need this reservation now!) we only limit ourselves to half of
the free space.  This makes this fio test

[torrent]
filename=torrent-test
rw=randwrite
size=4g
ioengine=sync
directory=/mnt/btrfs-test

go from taking around 45 minutes to 10 seconds on my freshly formatted 3 TiB
file system.  This doesn't seem to break my other enospc tests, but could really
use some more testing as this is a super scary change.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

In moving some enospc stuff around I noticed that when we unmount we are often
evicting the free space cache inodes before we do our last commit.  This isn't
bad, but it makes us constantly have to re-read the inodes back.  So instead
don't evict the cache until after we do our last commit, this will make things a
little less crappy and makes a future enospc change work properly.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

This is confusing code and isn't used by anything anymore, so delete it.
Signed-off-by: NJosef Bacik <josef@redhat.com>

This adds the hooks needed for readahead. In the readpage_end_io_hook,
the extent state is checked for the EXTENT_READAHEAD flag. Only in this
case the readahead hook is called, to keep the impact on non-ra as low
as possible.
Additionally, a hook for a failed IO is added, otherwise readahead would
wait indefinitely for the extent to finish.

Changes for v2:
 - eliminate race condition
Signed-off-by: NArne Jansen <sensille@gmx.net>

Add state information for readahead to btrfs_fs_info and btrfs_device

Changes v2:
 - don't wait in radix_trees
 - add own set of workers for readahead
Reviewed-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NArne Jansen <sensille@gmx.net>