This patch introduces uuids for subvolumes. Each
subvolume has it's own uuid. In case it was snapshotted,
it also contains parent_uuid. In case it was received,
it also contains received_uuid.

It also introduces subvolume ctime/otime/stime/rtime. The
first two are comparable to the times found in inodes. otime
is the origin/creation time and ctime is the change time.
stime/rtime are only valid on received subvolumes.
stime is the time of the subvolume when it was
sent. rtime is the time of the subvolume when it was
received.

Additionally to the times, we have a transid for each
time. They are updated at the same place as the times.

btrfs receive uses stransid and rtransid to find out
if a received subvolume changed in the meantime.

If an older kernel mounts a filesystem with the
extented fields, all fields become invalid. The next
mount with a new kernel will detect this and reset the
fields.
Signed-off-by: NAlexander Block <ablock84@googlemail.com>
Reviewed-by: NDavid Sterba <dave@jikos.cz>
Reviewed-by: NArne Jansen <sensille@gmx.net>
Reviewed-by: NJan Schmidt <list.btrfs@jan-o-sch.net>
Reviewed-by: NAlex Lyakas <alex.bolshoy.btrfs@gmail.com>

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: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NAlexander Block <ablock84@googlemail.com>

An ioctl interface is added to get the device statistic counters.
A second ioctl is added to atomically get and reset these counters.
Signed-off-by: NStefan Behrens <sbehrens@giantdisaster.de>

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>

Fix the size members of btrfs_ioctl_ino_path_args and
btrfs_ioctl_logical_ino_args. The user space btrfs-progs utilities used
__u64 and the kernel headers used __u32 before.
Signed-off-by: NAlexander Block <ablock84@googlemail.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NIlya Dryomov <idryomov@gmail.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>

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>

The new ioctls to follow backrefs are not clean for 32/64 bit
compat.  This reworks them for u64s everywhere.  They are brand new, so
there are no problems with changing the interface now.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

these ioctls make use of the new functions initially added for scrub. they
return all inodes belonging to a logical address (BTRFS_IOC_LOGICAL_INO) and
all paths belonging to an inode (BTRFS_IOC_INO_PATHS).
Signed-off-by: NJan Schmidt <list.btrfs@jan-o-sch.net>

These helper functions iterate back references and call a function for each
backref. There is also a function to resolve an inode to a path in the
file system.
Signed-off-by: NJan Schmidt <list.btrfs@jan-o-sch.net>

This will detect small random writes into files and
queue the up for an auto defrag process.  It isn't well suited to
database workloads yet, but works for smaller files such as rpm, sqlite
or bdb databases.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

setting the readonly flag prevents writes in case an error is detected
Signed-off-by: NArne Jansen <sensille@gmx.net>

adds ioctls necessary to start and cancel scrubs, to get current
progress and to get info about devices to be scrubbed.
Note that the scrub is done per-device and that the ioctl only
returns after the scrub for this devices is finished or has been
canceled.
Signed-off-by: NArne Jansen <sensille@gmx.net>

This adds an initial implementation for scrub. It works quite
straightforward. The usermode issues an ioctl for each device in the
fs. For each device, it enumerates the allocated device chunks. For
each chunk, the contained extents are enumerated and the data checksums
fetched. The extents are read sequentially and the checksums verified.
If an error occurs (checksum or EIO), a good copy is searched for. If
one is found, the bad copy will be rewritten.
All enumerations happen from the commit roots. During a transaction
commit, the scrubs get paused and afterwards continue from the new
roots.

This commit is based on the series originally posted to linux-btrfs
with some improvements that resulted from comments from David Sterba,
Ilya Dryomov and Jan Schmidt.
Signed-off-by: NArne Jansen <sensille@gmx.net>

This allows us to set a snapshot or a subvolume readonly or writable
on the fly.

Usage:

Set BTRFS_SUBVOL_RDONLY of btrfs_ioctl_vol_arg_v2->flags, and then
call ioctl(BTRFS_IOCTL_SUBVOL_SETFLAGS);

Changelog for v3:

- Change to pass __u64 as ioctl parameter.

Changelog for v2:

- Add _GETFLAGS ioctl.
- Check if the passed fd is the root of a subvolume.
- Change the name from _SNAP_SETFLAGS to _SUBVOL_SETFLAGS.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>

Usage:

Set BTRFS_SUBVOL_RDONLY of btrfs_ioctl_vol_arg_v2->flags, and call
ioctl(BTRFS_I0CTL_SNAP_CREATE_V2).

Implementation:

- Set readonly bit of btrfs_root_item->flags.
- Add readonly checks in btrfs_permission (inode_permission),
btrfs_setattr, btrfs_set/remove_xattr and some ioctls.

Changelog for v3:

- Eliminate btrfs_root->readonly, but check btrfs_root->root_item.flags.
- Rename BTRFS_ROOT_SNAP_RDONLY to BTRFS_ROOT_SUBVOL_RDONLY.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>

Update defrag ioctl, so one can choose lzo or zlib when turning
on compression in defrag operation.

Changelog:

v1 -> v2
- Add incompability flag.
- Fix to check invalid compress type.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>

If we had reserved some bytes in struct btrfs_ioctl_vol_args, we
wouldn't have to create a new structure for async snapshot creation.

Here we convert async snapshot ioctl to use a more generic ABI, as
we'll add more ioctls for snapshots/subvolumes in the future, readonly
snapshots for example.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Create a snap without waiting for it to commit to disk.  The ioctl is
ordered such that subsequent operations will not be contained by the
created snapshot, and the commit is initiated, but the ioctl does not
wait for the snapshot to commit to disk.

We return the specific transid to userspace so that an application can wait
for this specific snapshot creation to commit via the WAIT_SYNC ioctl.
Signed-off-by: NSage Weil <sage@newdream.net>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

START_SYNC will start a sync/commit, but not wait for it to
complete.  Any modification started after the ioctl returns is
guaranteed not to be included in the commit.  If a non-NULL
pointer is passed, the transaction id will be returned to
userspace.

WAIT_SYNC will wait for any in-progress commit to complete.  If a
transaction id is specified, the ioctl will block and then
return (success) when the specified transaction has committed.
If it has already committed when we call the ioctl, it returns
immediately.  If the specified transaction doesn't exist, it
returns EINVAL.

If no transaction id is specified, WAIT_SYNC will wait for the
currently committing transaction to finish it's commit to disk.
If there is no currently committing transaction, it returns
success.

These ioctls are useful for applications which want to impose an
ordering on when fs modifications reach disk, but do not want to
wait for the full (slow) commit process to do so.

Picky callers can take the transid returned by START_SYNC and
feed it to WAIT_SYNC, and be certain to wait only as long as
necessary for the transaction _they_ started to reach disk.

Sloppy callers can START_SYNC and WAIT_SYNC without a transid,
and provided they didn't wait too long between the calls, they
will get the same result.  However, if a second commit starts
before they call WAIT_SYNC, they may end up waiting longer for
it to commit as well.  Even so, a START_SYNC+WAIT_SYNC still
guarantees that any operation completed before the START_SYNC
reaches disk.
Signed-off-by: NSage Weil <sage@newdream.net>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NSage Weil <sage@newdream.net>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

df is a very loaded question in btrfs.  This gives us a way to get the per-space
usage information so we can tell exactly what is in use where.  This will help
us figure out ENOSPC problems, and help users better understand where their disk
space is going.
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

The btrfs defrag ioctl was limited to doing the entire file.  This
commit adds a new interface that can defrag a specific range inside
the file.

It can also force compression on the file, allowing you to selectively
compress individual files after they were created, even when mount -o
compress isn't turned on.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This patch needs to go along with my previous patch.  This lets us set the
default dir item's location to whatever root we want to use as our default
mounting subvol.  With this we don't have to use mount -o subvol=<tree id>
anymore to mount a different subvol, we can just set the new one and it will
just magically work.  I've done some moderate testing with this, mostly just
switching the default mount around, mounting subvols and the default mount at
the same time and such, everything seems to work.  Thanks,

Older kernels would generally be able to still mount the filesystem with the
default subvolume set, but it would result in a different volume being mounted,
which could be an even more unpleasant suprise for users.  So if you set your
default subvolume, you can't go back to older kernels.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

The search ioctl is a generic tool for doing btree searches from
userland applications.  The first user of the search ioctl is a
subvolume listing feature, but we'll also use it to find new
files in a subvolume.

The search ioctl allows you to specify min and max keys to search for,
along with min and max transid.  It returns the items along with a
header that includes the item key.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This patch adds snapshot/subvolume destroy ioctl.  A subvolume that isn't being
used and doesn't contains links to other subvolumes can be destroyed.
Signed-off-by: NYan Zheng <zheng.yan@oracle.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

The structure used to send device in btrfs ioctl calls was not
properly aligned, and so 32 bit ioctls would not work properly on
64 bit kernels.

We could fix this with compat ioctls, but we're just one byte away
and it doesn't make sense at this stage to carry about the compat ioctls
forever at this stage in the project.

This patch brings the ioctl arg up to an evenly aligned 4k.
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>

This patch adds an additional CLONE_RANGE ioctl to clone an arbitrary 
(block-aligned) file range to another file.  The original CLONE ioctl 
becomes a special case of cloning the entire file range.  The logic is a 
bit more complex now since ranges may be cloned to different offsets, and 
because we may only be cloning the beginning or end of a particular extent 
or checksum item.

An additional sanity check ensures the source and destination files aren't 
the same (which would previously deadlock), although eventually this could 
be extended to allow the duplication of file data at a different offset 
within the same file.

Any extents within the destination range in the target file are dropped.

We currently do not cope with the case where a compressed inline extent 
needs to be split.  This will probably require decompressing the extent 
into a temporary address_space, and inserting just the cloned portion as a 
new compressed inline extent.  For now, just return -EINVAL in this case.  
Note that this never comes up in the more common case of cloning an entire 
file.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

These ioctls let a user application hold a transaction open while it
performs a series of operations.  A final ioctl does a sync on the fs
(closing the current transaction).  This is the main requirement for
Ceph's OSD to be able to keep the data it's storing in a btrfs volume
consistent, and AFAICS it works just fine.  The application would do
something like

	fd = ::open("some/file", O_RDONLY);
	::ioctl(fd, BTRFS_IOC_TRANS_START);
	/* do a bunch of stuff */
	::ioctl(fd, BTRFS_IOC_TRANS_END);
or just
	::close(fd);

And to ensure it commits to disk,

	::ioctl(fd, BTRFS_IOC_SYNC);

When a transaction is held open, the trans_handle is attached to the
struct file (via private_data) so that it will get cleaned up if the
process dies unexpectedly.  A held transaction is also ended on fsync() to
avoid a deadlock.

A misbehaving application could also deliberately hold a transaction open,
effectively locking up the FS, so it may make sense to restrict something
like this to root or something.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Add a new ioctl to clone file data
Signed-off-by: NChris Mason <chris.mason@oracle.com>

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

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

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

This adds two types of btree defrag, a run time form that tries to
defrag recently allocated blocks in the btree when they are still in ram,
and an ioctl that forces defrag of all btree blocks.

File data blocks are not defragged yet, but this can make a huge difference
in sequential btree reads.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

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

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

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