Btrfs: introduce btrfs_next_old_item

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>
Btrfs: don't assume to be on the correct extent in add_all_parents

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>
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,
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>
Btrfs: delay iput with async extents

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>
Btrfs: avoid waiting for delayed refs when we must not

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>
Btrfs: support root level changes in __resolve_indirect_ref

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>
Btrfs: fix tree mod log for root replacements at leaf level

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>
Btrfs: always put insert_ptr modifications into the tree mod log

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>
Btrfs: leave critical region in btrfs_find_all_roots as soon as possible

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>
Btrfs: fix tree mod log rewind of ADD operations

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>
Btrfs: resolve tree mod log locking issue in btrfs_next_leaf

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>
Btrfs: don't count I/O statistic read errors for missing devices

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>
Btrfs: fix dio write vs buffered read race

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>
Btrfs: restore restriper state on all mounts

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>
Btrfs: resume balance on rw (re)mounts properly

This introduces btrfs_resume_balance_async(), which, given that
restriper state was recovered earlier by btrfs_recover_balance(),
resumes balance in btrfs-balance kthread.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Btrfs: use _IOR for BTRFS_IOC_SUBVOL_GETFLAGS

We used the wrong ioctl macro for the getflags ioctl before.
As we don't have the set/getflags ioctls in the user space ioctl.h
at the moment, it's safe to fix it now.

Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Alexander Block <ablock84@googlemail.com>
Btrfs: fix wrong check during log recovery

When we're evicting an inode during log recovery, we need to ensure that the inode
is not in orphan state any more, which means inode's run_time flags has _no_
BTRFS_INODE_HAS_ORPHAN_ITEM.  Thus, the BUG_ON was triggered because of a wrong
check for the flags.

Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: fix tree log remove space corner case

The tree log stuff can have allocated space that we end up having split
across a bitmap and a real extent.  The free space code does not deal with
this, it assumes that if it finds an extent or bitmap entry that the entire
range must fall within the entry it finds.  This isn't necessarily the case,
so rework the remove function so it can handle this case properly.  This
fixed two panics the user hit, first in the case where the space was
initially in a bitmap and then in an extent entry, and then the reverse
case.  Thanks,

Reported-and-tested-by: Shaun Reich <sreich@kde.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: hold a ref on the inode during writepages

We can race with unlink and not actually be able to do our igrab in
btrfs_add_ordered_extent.  This will result in all sorts of problems.
Instead of doing the complicated work to try and handle returning an error
properly from btrfs_add_ordered_extent, just hold a ref to the inode during
writepages.  If we cannot grab a ref we know we're freeing this inode anyway
and can just drop the dirty pages on the floor, because screw them we're
going to invalidate them anyway.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: run delayed directory updates during log replay

While we are resolving directory modifications in the
tree log, we are triggering delayed metadata updates to
the filesystem btrees.

This commit forces the delayed updates to run so the
replay code can find any modifications done.  It stops
us from crashing because the directory deleltion replay
expects items to be removed immediately from the tree.

Signed-off-by: Chris Mason <chris.mason@fusionio.com>
cc: stable@kernel.org