I noticed while looking at an extent_buffer race that we will
unconditionally return 1 if we get down to release_extent_buffer after
clearing the tree ref.  However we can easily race in here and get a ref on
the eb and not actually free the eb.  So make release_extent_buffer return 1
if it free'd the eb and 0 if not so we can be a little kinder to the vm.
Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

Changing printk_in_rcu to printk_ratelimited_in_rcu will suffice
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>

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: NJosef Bacik <jbacik@fusionio.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: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NJosef Bacik <josef@redhat.com>

The goal is to detect when drives start to get an increased error rate,
when drives should be replaced soon. Therefore statistic counters are
added that count IO errors (read, write and flush). Additionally, the
software detected errors like checksum errors and corrupted blocks are
counted.
Signed-off-by: NStefan Behrens <sbehrens@giantdisaster.de>

Fully utilize our extent state's new helper functions to use
fastpath as much as possible.
Signed-off-by: NLiu Bo <liubo2009@cn.fujitsu.com>
Reviewed-by: NJosef Bacik <josef@redhat.com>

We noticed that the ordered extent completion doesn't really rely on having
a page and that it could be done independantly of ending the writeback on a
page.  This patch makes us not do the threaded endio stuff for normal
buffered writes and direct writes so we can end page writeback as soon as
possible (in irq context) and only start threads to do the ordered work when
it is actually done.  Compression needs to be reworked some to take
advantage of this as well, but atm it has to do a find_get_page in its endio
handler so it must be done in its own thread.  This makes direct writes
quite a bit faster.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

These warnings are bogus since we will always have at least one page in an
eb, but to make the compiler happy just set ret = 0 in these two cases.
Thanks,
Btrfs: fix compile warnings in extent_io.c

These warnings are bogus since we will always have at least one page in an
eb, but to make the compiler happy just set ret = 0 in these two cases.
Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

The tree modification log needs two ways to create dummy extent buffers,
once by allocating a fresh one (to rebuild an old root) and once by
cloning an existing one (to make private rewind modifications) to it.
Signed-off-by: NJan Schmidt <list.btrfs@jan-o-sch.net>

In tree_insert, var *entry is used in the loop only, and is useless
out of the loop. Remove the useless assignment after the loop.
Signed-off-by: NWang Sheng-Hui <shhuiw@gmail.com>

The return value of find_first_extent_bit is 1 or 0, no < 0.
And if found something, return 0; if nothing was found, return 1.
Fix the comment.
Signed-off-by: NWang Sheng-Hui <shhuiw@gmail.com>

num_extent_pages returns the number of pages in the specific range, not
the index of the last page in the eb range.

btrfs_release_extent_buffer_page is called with start_idx set 0 in current
codes, so it's not a problem yet. But the logic is indeed wrong.

Fix it here.
Signed-off-by: NWang Sheng-Hui <shhuiw@gmail.com>

No 'delete' arg is used for clear_state_bit.
Cleanup the comment.
Signed-off-by: NWang Sheng-Hui <shhuiw@gmail.com>

If we happen to alloc a extent buffer and then alloc a page and notice that
page is already attached to an extent buffer, we will only unlock it and
free our existing eb.  Any pages currently attached to that eb will be
properly freed, but we don't do the page_cache_release() on the page where
we noticed the other extent buffer which can cause us to leak pages and I
hope cause the weird issues we've been seeing in this area.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

A user reported a panic where we were trying to fix a bad mirror but the
mirror number we were giving was 0, which is invalid.  This is because we
don't do the transid verification until after the read, so as far as the
read code is concerned the read was a success.  So instead store the mirror
we read from so that if there is some failure post read we know which mirror
to try next and which mirror needs to be fixed if we find a good copy of the
block.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

clear_extent_bit()
{
    next_node = rb_next(&state->rb_node);
    ...
    clear_state_bit(state);  <-- this may free next_node
    if (next_node) {
        state = rb_entry(next_node);
        ...
    }
}

clear_state_bit() calls merge_state() which may free the next node
of the passing extent_state, so clear_extent_bit() may end up
referencing freed memory.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>

Currently it returns a set of bits that were cleared, but this return
value is not used at all.

Moreover it doesn't seem to be useful, because we may clear the bits
of a few extent_states, but only the cleared bits of last one is
returned.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>

bio_alloc() has the possibility of returning NULL.
So, it is necessary to check the return value.
Signed-off-by: NTsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

We'd have to be passing bogus extent buffers for this uninit variable to
actually be used, but set it to zero just in case.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Since we need to read and write extent buffers in their entirety we can't use
the normal bio_readpage_error stuff since it only works on a per page basis.  So
instead make it so that if we see an io error in endio we just mark the eb as
having an IO error and then in btree_read_extent_buffer_pages we will manually
try other mirrors and then overwrite the bad mirror if we find a good copy.
This works with larger than page size blocks.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

lock_extent_buffer_for_io needs to loop around and make sure the
writeback bits are not set.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This patch simplifies how we track our extent buffers.  Previously we could exit
writepages with only having written half of an extent buffer, which meant we had
to track the state of the pages and the state of the extent buffers differently.
Now we only read in entire extent buffers and write out entire extent buffers,
this allows us to simply set bits in our bflags to indicate the state of the eb
and we no longer have to do things like track uptodate with our iotree.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Because an eb can have multiple pages we need to make sure that all pages within
the eb are markes as accessed, since releasepage can be called against any page
in the eb.  This will keep us from possibly evicting hot eb's when we're doing
larger than pagesize eb's.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

Because btrfs cow's we can end up with extent buffers that are no longer
necessary just sitting around in memory.  So instead of evicting these pages, we
could end up evicting things we actually care about.  Thus we have
free_extent_buffer_stale for use when we are freeing tree blocks.  This will
make it so that the ref for the eb being in the radix tree is dropped as soon as
possible and then is freed when the refcount hits 0 instead of waiting to be
released by releasepage.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

We can run into a problem where we find an eb for our existing page already on
the radix tree but it has a ref count of 0.  It hasn't yet been removed by RCU
yet so this can cause issues where we will use the EB after free.  So do
atomic_inc_not_zero on the exists->refs and if it is zero just do
synchronize_rcu() and try again.  We won't have to worry about new allocators
coming in since they will block on the page lock at this point.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

We spend a lot of time looking up extent buffers from pages when we could just
store the pointer to the eb the page is associated with in page->private.  This
patch does just that, and it makes things a little simpler and reduces a bit of
CPU overhead involved with doing metadata IO.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

A few years ago the btrfs code to support blocks lager than
the page size was disabled to fix a few corner cases in the
page cache handling.  This fixes the code to properly support
large metadata blocks again.

Since current kernels will crash early and often with larger
metadata blocks, this adds an incompat bit so that older kernels
can't mount it.

This also does away with different blocksizes for nodes and leaves.
You get a single block size for all tree blocks.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

 btrfs currently handles most errors with BUG_ON. This patch is a work-in-
 progress but aims to handle most errors other than internal logic
 errors and ENOMEM more gracefully.

 This iteration prevents most crashes but can run into lockups with
 the page lock on occasion when the timing "works out."
Signed-off-by: NJeff Mahoney <jeffm@suse.com>

 set_extent_bit can do exclusive locking but only when called by lock_extent*,

 Drop the exclusive bits argument except when called by lock_extent.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>

 lock_extent and unlock_extent are always called with GFP_NOFS, drop the
 argument and use GFP_NOFS consistently.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>

Signed-off-by: NJeff Mahoney <jeffm@suse.com>

This pushes failures from the submit_bio_hook callbacks,
btrfs_submit_bio_hook and btree_submit_bio_hook into the callers, including
callers of submit_one_bio where it catches the failures with BUG_ON.

It also pushes up through the ->readpage_io_failed_hook to
end_bio_extent_writepage where the error is already caught with BUG_ON.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>

In submit_extent_page, there's a visually noisy if statement that, in
the midst of other conditions, does the tree dependency for tree->ops
and tree->ops->merge_bio_hook before calling it, and then another
condition afterwards. If an error is returned from merge_bio_hook,
there's no way to catch it. It's considered a routine "1" return
value instead of a failure.

This patch factors out the dependency check into a new local merge_bio
routine and BUG's on an error. The if statement is less noisy as a side-
effect.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>

There is only one caller of clear_extent_bit that checks the return value
and it only checks if it's negative. Since there are no users of the
returned bits functionality of clear_extent_bit, stop returning it
and avoid complicating error handling.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>

The *_state functions can only return 0 or -EEXIST. This patch addresses
the cases where those functions returning -EEXIST represent a locking
failure. It handles them by panicking with an appropriate error message.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>

Signed-off-by: NCong Wang <amwang@redhat.com>

If btrfs reads a block and finds a parent transid mismatch, it clears
the uptodate flags on the extent buffer, and the pages inside it.  But
we only clear the uptodate bits in the state tree if the block straddles
more than one page.

This is from an old optimization from to reduce contention on the extent
state tree.  But it is buggy because the code that retries a read from
a different copy of the block is going to find the uptodate state bits
set and skip the IO.

The end result of the bug is that we'll never actually read the good
copy (if there is one).

The fix here is to always clear the uptodate state bits, which is safe
because this code is only called when the parent transid fails.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

In clear_extent_bit, it is enough that next node is adjacent in tree level.
Signed-off-by: NLiu Bo <liubo2009@cn.fujitsu.com>

clear_state_bit will do merge_state for us, so kick out the redundant one.
Signed-off-by: NLiu Bo <liubo2009@cn.fujitsu.com>

Clearing a range's bits is different with setting them, since we don't
need to touch them when states do not contain bits we want.
Signed-off-by: NLiu Bo <liubo2009@cn.fujitsu.com>