The btrfs macros to access individual struct members on disk were
sending the same variable to functions that expected different types
of endianness.  This fix explicitly creates a variable of the correct
type instead of abusing a single variable for mixed purposes.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Snapshot and subvolume creation no longer need this helper.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This patch gives us the space we will need in order to have different csum
algorithims at some point in the future.  We save the csum algorithim type
in the superblock, and use those instead of define's.
Signed-off-by: NJosef Bacik <jbacik@redhat.com>

This needs to be applied on top of my previous patches, but is needed for more
than just my new stuff.  We're going to the wrong label when we have an error,
we try to stop the workers, but they are started below all of this code.  This
fixes it so we go to the right error label and not panic when we fail one of
these cases.
Signed-off-by: NJosef Bacik <jbacik@redhat.com>

This adds the necessary disk format for handling compatibility flags
in the future to handle disk format changes.  We have a compat_flags,
compat_ro_flags and incompat_flags set for the super block.  Compat
flags will be to hold the features that are compatible with older
versions of btrfs, compat_ro flags have features that are compatible
with older versions of btrfs if the fs is mounted read only, and
incompat_flags has features that are incompatible with older versions
of btrfs.  This also axes the compat_flags field for the inode and
just makes the flags field a 64bit field, and changes the root item
flags field to 64bit.
Signed-off-by: NJosef Bacik <jbacik@redhat.com>

Cleans the code up a little and also avoids a sparse warning due to the
incorrect cast in the current version of the code.
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Provide a void __user *argp pointer so that we can avoid duplicating
the cast for various sub-command calls.
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Make sure to propagate fmode_t properly and use the right constants for
it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Shut up various sparse warnings about symbols that should be either
static or have their declarations in scope.
Signed-off-by: NChristoph Hellwig <hch@lst.de>

It is called by btrfs_sync_fs.
Signed-off-by: NSage Weil <sage@newdream.net>

Remove unneeded debugging sanity check.  It gets corrupted anyway when
multiple btrfs file systems are mounted, throwing bad warnings along the
way.
Signed-off-by: NSage Weil <sage@newdream.net>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

The file preallocation code reversed the logic to force nodatacow.
This fixes it.

This the lockdep complaint by having a different mutex to gaurd caching the
block group, so you don't end up with this backwards dependancy.  Thank you,
Signed-off-by: NJosef Bacik <jbacik@redhat.com>

The btrfs write_cache_pages call has a flush function so that it submits
the bio it has been building before it waits on any writeback pages.

This adds a check so that flush only happens on writeback pages.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

The log replay produces dirty roots. These dirty roots
should be dropped immediately if the fs is mounted as
ro. Otherwise they can be added to the dirty root list
again when remounting the fs as rw. Thank you,
Signed-off-by: NYan Zheng <zheng.yan@oracle.com>

The btrfs git kernel trees is used to build a standalone tree for
compiling against older kernels.  This commit makes the standalone tree
work with 2.6.27
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This fixes compile problems with linux-next
Signed-off-by: NChris Mason <chris.mason@oracle.com>

* open/close_bdev_excl -> open/close_bdev_exclusive
* blkdev_issue_discard takes a GFP mask now
* Fix blkdev_issue_discard usage now that it is enabled
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This patch fixes what I hope is the last early ENOSPC bug left.  I did not know
that pinned extents would merge into one big extent when inserted on to the
pinned extent tree, so I was adding free space to a block group that could
possibly span multiple block groups.

This is a big issue because first that space doesn't exist in that block group,
and second we won't actually use that space because there are a bunch of other
checks to make sure we're allocating within the constraints of the block group.

This patch fixes the problem by adding the btrfs_add_free_space to
btrfs_update_pinned_extents which makes sure we are adding the appropriate
amount of free space to the appropriate block group.  Thanks much to Lee Trager
for running my myriad of debug patches to help me track this problem down.
Thank you,
Signed-off-by: NJosef Bacik <jbacik@redhat.com>

fsync log replay can change the filesystem, so it cannot be delayed until
mount -o rw,remount, and it can't be forgotten entirely.  So, this patch
changes btrfs to do with reiserfs, ext3 and xfs do, which is to do the
log replay even when mounted readonly.

On a readonly device if log replay is required, the mount is aborted.

Getting all of this right had required fixing up some of the error
handling in open_ctree.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

While building large bios in writepages, btrfs may end up waiting
for other page writeback to finish if WB_SYNC_ALL is used.

While it is waiting, the bio it is building has a number of pages with the
writeback bit set and they aren't getting to the disk any time soon.  This
lowers the latencies of writeback in general by sending down the bio being
built before waiting for other pages.

The bio submission code tries to limit the total number of async bios in
flight by waiting when we're over a certain number of async bios.  But,
the waits are happening while writepages is building bios, and this can easily
lead to stalls and other problems for people calling wait_on_page_writeback.

The current fix is to let the congestion tests take care of waiting.

sync() and others make sure to drain the current async requests to make
sure that everything that was pending when the sync was started really get
to disk.  The code would drain pending requests both before and after
submitting a new request.

But, if one of the requests is waiting for page writeback to finish,
the draining waits might block that page writeback.  This changes the
draining code to only wait after submitting the bio being processed.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

The extent based waiting was using more CPU, and other fixes have helped
with the unplug storm problems.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

For larger multi-device filesystems, there was logic to limit the
number of devices unplugged to just the page that was sent to our sync_page
function.

But, the code wasn't always unplugging the right device.  Since this was
just an optimization, disable it for now.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

In insert_extents(), when ret==1 and last is not zero, it should
check if the current inserted item is the last item in this batching
inserts. If so, it should just break from loop. If not, 'cur =
insert_list->next' will make no sense because the list is empty now,
and 'op' will point to an unexpectable place.

There are also some trivial fixs in this patch including one comment
typo error and deleting two redundant lines.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

For a directory tree:

/mnt/subvolA/subvolB

btrfsctl -s /mnt/subvolA/subvolB /mnt

Will create a directory loop with subvolA under subvolB.  This
commit uses the forward refs for each subvol and snapshot to error out
before creating the loop.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Subvols and snapshots can now be referenced from any point in the directory
tree.  We need to maintain back refs for them so we can find lost
subvols.

Forward refs are added so that we know all of the subvols and
snapshots referenced anywhere in the directory tree of a single subvol.  This
can be used to do recursive snapshotting (but they aren't yet) and it is
also used to detect and prevent directory loops when creating new snapshots.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Each subvolume has its own private inode number space, and so we need
to fill in different device numbers for each subvolume to avoid confusing
applications.

This commit puts a struct super_block into struct btrfs_root so it can
call set_anon_super() and get a different device number generated for
each root.

btrfs_rename is changed to prevent renames across subvols.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Before, all snapshots and subvolumes lived in a single flat directory.  This
was awkward and confusing because the single flat directory was only writable
with the ioctls.

This commit changes the ioctls to create subvols and snapshots at any
point in the directory tree.  This requires making separate ioctls for
snapshot and subvol creation instead of a combining them into one.

The subvol ioctl does:

btrfsctl -S subvol_name parent_dir

After the ioctl is done subvol_name lives inside parent_dir.

The snapshot ioctl does:

btrfsctl -s path_for_snapshot root_to_snapshot

path_for_snapshot can be an absolute or relative path.  btrfsctl breaks it up
into directory and basename components.

root_to_snapshot can be any file or directory in the FS.  The snapshot
is taken of the entire root where that file lives.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Some people are still reporting problems with early enospc.  This
will help narrown down the cause.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

In my batch delete/update/insert patch I introduced a free space leak.  The
extent that we do the original search on in free_extents is never pinned, so we
always update the block saying that it has free space, but the free space never
actually gets added to the free space tree, since op->del will always be 0 and
it's never actually added to the pinned extents tree.

This patch fixes this problem by making sure we call pin_down_bytes on the
pending extent op and set op->del to the return value of pin_down_bytes so
update_block_group is called with the right value.  This seems to fix the case
where we were getting ENOSPC when there was plenty of space available.
Signed-off-by: NJosef Bacik <jbacik@redhat.com>

Add a missing kzalloc() return pointer check in add_missing_dev().
Signed-off-by: NChris Mason <chris.mason@oracle.com>

In worker_loop(), the func should check whether it has been requested to stop
before it decides to schedule out.

Otherwise if the stop request(also the last wake_up()) sent by
btrfs_stop_workers() happens when worker_loop() running after the "while"
judgement and before schedule(), woker_loop() will schedule away and never be
woken up, which will also cause btrfs_stop_workers() wait forever.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

When extent needs to be split, btrfs_mark_extent_written truncates the extent
first, then inserts a new extent and increases the reference count.

The race happens if someone else deletes the old extent before the new extent
is inserted. The fix here is increase the reference count in advance. This race
is similar to the race in btrfs_drop_extents that was recently fixed.
Signed-off-by: NYan Zheng <zheng.yan@oracle.com>

Seed device is a special btrfs with SEEDING super flag
set and can only be mounted in read-only mode. Seed
devices allow people to create new btrfs on top of it.

The new FS contains the same contents as the seed device,
but it can be mounted in read-write mode.

This patch does the following:

1) split code in btrfs_alloc_chunk into two parts. The first part does makes
the newly allocated chunk usable, but does not do any operation that modifies
the chunk tree. The second part does the the chunk tree modifications. This
division is for the bootstrap step of adding storage to the seed device.

2) Update device management code to handle seed device.
The basic idea is: For an FS grown from seed devices, its
seed devices are put into a list. Seed devices are
opened on demand at mounting time. If any seed device is
missing or has been changed, btrfs kernel module will
refuse to mount the FS.

3) make btrfs_find_block_group not return NULL when all
block groups are read-only.
Signed-off-by: NYan Zheng <zheng.yan@oracle.com>

This patch adds mount ro and remount support. The main
changes in patch are: adding btrfs_remount and related
helper function; splitting the transaction related code
out of close_ctree into btrfs_commit_super; updating
allocator to properly handle read only block group.
Signed-off-by: NYan Zheng <zheng.yan@oracle.com>

While profiling the allocator I noticed a good amount of time was being spent in
finish_current_insert and del_pending_extents, and as the filesystem filled up
more and more time was being spent in those functions.  This patch aims to try
and reduce that problem.  This happens two ways

1) track if we tried to delete an extent that we are going to update or insert.
Once we get into finish_current_insert we discard any of the extents that were
marked for deletion.  This saves us from doing unnecessary work almost every
time finish_current_insert runs.

2) Batch insertion/updates/deletions.  Instead of doing a btrfs_search_slot for
each individual extent and doing the needed operation, we instead keep the leaf
around and see if there is anything else we can do on that leaf.  On the insert
case I introduced a btrfs_insert_some_items, which will take an array of keys
with an array of data_sizes and try and squeeze in as many of those keys as
possible, and then return how many keys it was able to insert.  In the update
case we search for an extent ref, update the ref and then loop through the leaf
to see if any of the other refs we are looking to update are on that leaf, and
then once we are done we release the path and search for the next ref we need to
update.  And finally for the deletion we try and delete the extent+ref in pairs,
so we will try to find extent+ref pairs next to the extent we are trying to free
and free them in bulk if possible.

This along with the other cluster fix that Chris pushed out a bit ago helps make
the allocator preform more uniformly as it fills up the disk.  There is still a
slight drop as we fill up the disk since we start having to stick new blocks in
odd places which results in more COW's than on a empty fs, but the drop is not
nearly as severe as it was before.
Signed-off-by: NJosef Bacik <jbacik@redhat.com>