Fix a bug that triggered asserts in btrfs_balance() in both normal and
resume modes -- restriper state was not properly restored on read-only
mounts.  This factors out resuming code from btrfs_restore_balance(),
which is now also called earlier in the mount sequence to avoid the
problem of some early writes getting the old profile.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

Miao pointed out there's a problem with mixing dio writes and buffered
reads.  If the read happens between us invalidating the page range and
actually locking the extent we can bring in pages into page cache.  Then
once the write finishes if somebody tries to read again it will just find
uptodate pages and we'll read stale data.  So we need to lock the extent and
check for uptodate bits in the range.  If there are uptodate bits we need to
unlock and invalidate again.  This will keep this race from happening since
we will hold the extent locked until we create the ordered extent, and then
teh read side always waits for ordered extents.  There was also a race in
how we updated i_size, previously we were relying on the generic DIO stuff
to adjust the i_size after the DIO had completed, but this happens outside
of the extent lock which means reads could come in and not see the updated
i_size.  So instead move this work into where we create the extents, and
then this way the update ordered i_size stuff works properly in the endio
handlers.  Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>

It is normal behaviour of the low level btrfs function btrfs_map_bio()
to complete a bio with -EIO if the device is missing, instead of just
preventing the bio creation in an earlier step.
This used to cause I/O statistic read error increments and annoying
printk_ratelimited messages. This commit fixes the issue.
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Reported-by: Carey Underwood <cwillu@cwillu.com>

With the tree mod log, we may end up with two roots (the current root and a
rewinded version of it) both pointing to two leaves, l1 and l2, of which l2
had already been cow-ed in the current transaction. If we don't rewind any
tree blocks, we cannot have two roots both pointing to an already cowed tree
block.

Now there is btrfs_next_leaf, which has a leaf locked and wants a lock on
the next (right) leaf. And there is push_leaf_left, which has a (cowed!)
leaf locked and wants a lock on the previous (left) leaf.

In order to solve this dead lock situation, we use try_lock in
btrfs_next_leaf (only in case it's called with a tree mod log time_seq
paramter) and if we fail to get a lock on the next leaf, we give up our lock
on the current leaf and retry from the very beginning.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

When a MOD_LOG_KEY_ADD operation is rewinded, we remove the key from the
tree block. If its not the last key, removal involves a move operation.
This move operation was explicitly done before this commit.

However, at insertion time, there's a move operation before the actual
addition to make room for the new key, which is recorded in the tree mod
log as well. This means, we must drop the move operation when rewinding the
add operation, because the next operation we'll be rewinding will be the
corresponding MOD_LOG_MOVE_KEYS operation.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

When delayed refs exist, btrfs_find_all_roots used to hold the delayed ref
mutex way longer than actually required. We ought to drop it immediately
after we're done collecting all the delayed refs.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

Several callers of insert_ptr set the tree_mod_log parameter to 0 to avoid
addition to the tree mod log. In fact, we need all of those operations. This
commit simply removes the additional parameter and makes addition to the
tree mod log unconditional.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

For the tree mod log, we don't log any operations at leaf level. If the root
is at the leaf level (i.e. the tree consists only of the root), then
__tree_mod_log_oldest_root will find a ROOT_REPLACE operation in the log
(because we always log that one no matter which level), but no other
operations.

With this patch __tree_mod_log_oldest_root exits cleanly instead of
BUGging in this situation. get_old_root checks if its really a root at leaf
level in case we don't have any operations and WARNs if this assumption
breaks.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

With the tree mod log, we can have a tree that's two levels high, but
btrfs_search_old_slot may still return a path with the tree root at level
one instead. __resolve_indirect_ref must care for this and accept parents in
a lower level than expected.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

We track two conditions to decide if we should sleep while waiting for more
delayed refs, the number of delayed refs (num_refs) and the first entry in
the list of blockers (first_seq).

When we suspect staleness, we save num_refs and do one more cycle. If
nothing changes, we then save first_seq for later comparison and do
wait_event. We ought to save first_seq the very same moment we're saving
num_refs. Otherwise we cannot be sure that nothing has changed and we might
start waiting when we shouldn't, which could lead to starvation.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

There is some concern that these iput()'s could be the final iputs and could
induce lockups on people waiting on writeback.  This would happen in the
rare case that we don't create ordered extents because of an error, but it
is theoretically possible and we already have a mechanism to deal with this
so just make them delayed iputs to negate any worry.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

When fixing up the locking in the delayed ref destruction work I accidently
broke the locking myself ;(.  Add back a spin_lock that should be there and
we are now all set.  Thanks,
Btrfs: add a missing spin_lock

When fixing up the locking in the delayed ref destruction work I accidently
broke the locking myself ;(.  Add back a spin_lock that should be there and
we are now all set.  Thanks,
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

add_all_parents did assume that path is already at a correct extent data
item, which may not be true in case of data extents that were partly
rewritten and splitted.

We need to check if we're on a matching extent for every item and only
for the ones after the first. The loop is changed to do this now.

This patch also fixes a bug introduced with commit 3b127fd8 "Btrfs:
remove obsolete btrfs_next_leaf call from __resolve_indirect_ref".
The removal of next_leaf did sometimes result in slot==nritems when
the above described case happens, and thus resulting in invalid values
(e.g. wanted_obejctid) in add_all_parents (leading to missed backrefs
or even crashes).
Signed-off-by: Alexander Block <ablock84@googlemail.com>
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

We introduce btrfs_next_old_item that uses btrfs_next_old_leaf instead
of btrfs_next_leaf.

btrfs_next_item is also changed to simply call btrfs_next_old_item with
time_seq being 0.
Signed-off-by: Alexander Block <ablock84@googlemail.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

Avoid warning in 32 bit machines
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

gcc was giving an uninit variable warning here.  Strictly
speaking we don't need to init it, but this will make things
much less error prone.
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

Update to the latest btrfs's maintainer mail and git repo.
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@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>

Since we have two trees for recording pinned extents, we need to go through
both of them to make sure that we've done everything clean.
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

We've forgotten to clear extent states in pinned tree, which will results in
space counter mismatch and memory leak:

WARNING: at fs/btrfs/extent-tree.c:7537 btrfs_free_block_groups+0x1f3/0x2e0 [btrfs]()
...
space_info 2 has 8380416 free, is not full
space_info total=12582912, used=4096, pinned=4096, reserved=0, may_use=0, readonly=4194304
btrfs state leak: start 29364224 end 29376511 state 1 in tree ffff880075f20090 refs 1
...
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

Seeding devices are not supposed to change any more.
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

When we move a file into a directory with compression flag, we need to
inherite BTRFS_INODE_COMPRESS and clear BTRFS_INODE_NOCOMPRESS as well.
But if we move a file into a directory without compression flag, we need
to clear both of them.

It is the way how our setflags deals with compression flag, so keep
the same behaviour here.
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

It's a bug, but it happens to work, as BTRFS_COMPRESS_LZO == 2, which
has only one bit set.
Signed-off-by: Li Zefan <lizefan@huawei.com>

If a file has 3 small extents:

| ext1 | ext2 | ext3 |

Running "btrfs fi defrag" will only defrag the last two extents, if those
extent mappings hasn't been read into memory from disk.

This bug was introduced by commit 17ce6ef8
("Btrfs: add a check to decide if we should defrag the range")

The cause is, that commit looked into previous and next extents using
lookup_extent_mapping() only.

While at it, remove the code that checks the previous extent, since
it's sufficient to check the next extent.
Signed-off-by: Li Zefan <lizefan@huawei.com>

I removed this in an earlier commit and I was wrong.  Because compression
can return from filemap_fdatawrite() without having actually set any of it's
pages as writeback() it can make filemap_fdatawait() do essentially nothing,
and then we won't find any ordered extents because they may not have been
created yet.  So not only does this make fsync() completely useless, but it
will also screw up if you truncate on a non-page aligned offset since we
zero out the end and then wait on ordered extents and then call drop caches.
We can drop the cache before the io completes and then we try to unpin the
extent we just wrote we won't find it and everything goes sideways.  So fix
this by putting it back and put a giant comment there to keep me from trying
to remove it in the future.  Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>

A user reported lots of problems using compression on the new code and it
turns out part of the problem was that igrab() was failing when we added a
new ordered extent.  This is because when writing out an inode under
compression we immediately return without actually doing anything to the
pages, and then in another thread at some point down the line actually do
the ordered dance.  The problem is between the point that we start writeback
and we actually add the ordered extent we could be trying to reclaim the
inode, which makes igrab() return NULL.  So we need to do an igrab() when we
create the async extent and then drop it when we are done with it.  This
makes sure we stay pinned in memory until the ordered extent can get a
reference on it and we are good to go.  With this patch we no longer panic
in btrfs_finish_ordered_io().  Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>

Because btrfs can remove the device that was mounted we need to have a
->show_devname so that in this case we can print out some other device in
the file system to /proc/mount.  So if there are multiple devices in a btrfs
file system we will just print the device with the lowest devid that we can
find.  This will make everything consistent and deal with device removal
properly.  The drawback is if you mount with a device that is higher than
the lowest devicd it won't show up as the mounted device in /proc/mounts,
but this is a small price to pay. This was inspired by Miao Xie's patch.
Thanks,
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <josef@redhat.com>

Al pointed out that we can just toss out the old name on a device and add a
new one arbitrarily, so anybody who uses device->name in printk could
possibly use free'd memory.  Instead of adding locking around all of this he
suggested doing it with RCU, so I've introduced a struct rcu_string that
does just that and have gone through and protected all accesses to
device->name that aren't under the uuid_mutex with rcu_read_lock().  This
protects us and I will use it for dealing with removing the device that we
used to mount the file system in a later patch.  Thanks,
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <josef@redhat.com>

I was getting hung on umount when a transaction was aborted because a range
of one of the free space inodes was still locked.  This is because the nocow
stuff doesn't unlock anything on error.  This fixed the problem and I
verified that is what was happening.  Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>

So we're forcing the eb's to have their ref count set to 1 so invalidatepage
works but this breaks lots of things, for example root nodes, and is just
plain wrong, we don't need to just evict all of this stuff.  Also drop the
invalidatepage altogether and add a page_cache_release().  With this patch
we no longer hang when trying to access the root nodes after an aborted
transaction and we no longer leak memory.  Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>

If a transaction commit fails we don't abort it so we don't set an error on
the file system.  This patch fixes that by actually calling the abort stuff
and then adding a check for a fs error in the transaction start stuff to
make sure it is caught properly.  Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>

I was getting lots of hung tasks and a NULL pointer dereference because we
are not cleaning up the transaction properly when it aborts.  First we need
to reset the running_transaction to NULL so we don't get a bad dereference
for any start_transaction callers after this.  Also we cannot rely on
waitqueue_active() since it's just a list_empty(), so just call wake_up()
directly since that will do the barrier for us and such.  Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>

The transaction abort stuff was throwing warnings from the list debugging
code because we do a list_del_init outside of the delayed_refs spin lock.
The delayed refs locking makes baby Jesus cry so it's not hard to get wrong,
but we need to take the ref head mutex to make sure it's not being processed
currently, and so if it is we need to drop the spin lock and then take and
drop the mutex and do the search again.  If we can take the mutex then we
can safely remove the head from the list and carry on.  Now when the
transaction aborts I don't get the list debugging warnings.  Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>

While doing my enospc work I got a transaction abortion that resulted in a
panic when we tried to unlock_page() an already unlocked page.  This is
because we aren't calling extent_clear_unlock_delalloc with the locked page
so it was unlocking all the pages in the range.  This is wrong since
__extent_writepage expects to have the page locked still unless we return
*page_started as 1.  This should keep us from panicing.  Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>

When adding to the tree modification log, we grab two locks at different
stages. We must not drop the outer lock until we're done with section
protected by the inner lock. This moves the unlock call for the outer lock
to the appropriate position.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

To make sense of the tree mod log, the backref walker not only needs
btrfs_search_old_slot, but it also called btrfs_next_leaf, which in turn was
calling btrfs_search_slot. This obviously didn't give the correct result.

This commit adds btrfs_next_old_leaf, a drop-in replacement for
btrfs_next_leaf with a time_seq parameter. If it is zero, it behaves exactly
like btrfs_next_leaf. If it is non-zero, it will use btrfs_search_old_slot
with this time_seq parameter.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

In __tree_mod_log_oldest_root() we must return the found operation even if
it's not a ROOT_REPLACE operation. Otherwise, the caller assumes that there
are no operations to be rewinded and returns immediately.

The code in the caller is modified to improve readability.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

get_old_root could race with root node updates because we weren't locking
the node early enough. Use btrfs_read_lock_root_node to grab the root locked
in the very beginning and release the lock as soon as possible (just like
btrfs_search_slot does).
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

When resolving indirect refs, we used to call btrfs_next_leaf in case we
didn't find an exact match. While we should find exact matches most of the
time, in case we don't, we must continue searching. Treating those matches
differently depending on the level we're searching doesn't make sense.

Even worse, we might end up searching for a key larger than the largest, in
which case there is no next_leaf and subsequent jobs would fail. This commit
drops the bogous lines.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>