In order to save free space cache, we need an inode to hold the data, and we
need a special item to point at the right inode for the right block group.  So
first, create a special item that will point to the right inode, and the number
of extent entries we will have and the number of bitmaps we will have.  We
truncate and pre-allocate space everytime to make sure it's uptodate.

This feature will be turned on as soon as you mount with -o space_cache, however
it is safe to boot into old kernels, they will just generate the cache the old
fashion way.  When you boot back into a newer kernel we will notice that we
modified and not the cache and automatically discard the cache.
Signed-off-by: NJosef Bacik <josef@redhat.com>

BTRFS does not define a '->write_super()' method, so it should
not mark its superblock as dirty. This looks like some left-over.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Acked-by: NChris Mason <chris.mason@oracle.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... and let iput_final() do the actual eviction or retention
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

NB: do we want btrfs_wait_ordered_range() on eviction of
inodes with positive i_nlink on subvolume with zero root_refs?
If not, btrfs_evict_inode() can be simplified by unconditionally
bailing out in case of i_nlink > 0 in the very beginning...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

add I_CLEAR instead of replacing I_FREEING with it.  I_CLEAR is
equivalent to I_FREEING for almost all code looking at either;
it's there to keep track of having called clear_inode() exactly
once per inode lifetime, at some point after having set I_FREEING.
I_CLEAR and I_FREEING never get set at the same time with the
current code, so we can switch to setting i_flags to I_FREEING | I_CLEAR
instead of I_CLEAR without loss of information.  As the result of
such change, checks become simpler and the amount of code that needs
to know about I_CLEAR shrinks a lot.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Replace inode_setattr with opencoded variants of it in all callers.  This
moves the remaining call to vmtruncate into the filesystem methods where it
can be replaced with the proper truncate sequence.

In a few cases it was obvious that we would never end up calling vmtruncate
so it was left out in the opencoded variant:

 spufs: explicitly checks for ATTR_SIZE earlier
 btrfs,hugetlbfs,logfs,dlmfs: explicitly clears ATTR_SIZE earlier
 ufs: contains an opencoded simple_seattr + truncate that sets the filesize just above

In addition to that ncpfs called inode_setattr with handcrafted iattrs,
which allowed to trim down the opencoded variant.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Remove the current bio flags and reuse the request flags for the bio, too.
This allows to more easily trace the type of I/O from the filesystem
down to the block driver.  There were two flags in the bio that were
missing in the requests:  BIO_RW_UNPLUG and BIO_RW_AHEAD.  Also I've
renamed two request flags that had a superflous RW in them.

Note that the flags are in bio.h despite having the REQ_ name - as
blkdev.h includes bio.h that is the only way to go for now.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

1.  The BTRFS_IOC_CLONE and BTRFS_IOC_CLONE_RANGE ioctls should check
whether the donor file is append-only before writing to it.

2.  The BTRFS_IOC_CLONE_RANGE ioctl appears to have an integer
overflow that allows a user to specify an out-of-bounds range to copy
from the source file (if off + len wraps around).  I haven't been able
to successfully exploit this, but I'd imagine that a clever attacker
could use this to read things he shouldn't.  Even if it's not
exploitable, it couldn't hurt to be safe.
Signed-off-by: NDan Rosenberg <dan.j.rosenberg@gmail.com>
cc: stable@kernel.org
Signed-off-by: NChris Mason <chris.mason@oracle.com>

The CLONE and CLONE_RANGE ioctls round up the range of extents being
cloned to the block size when the range to clone extends to the end of file
(this is always the case with CLONE).  It was then using that offset when
extending the destination file's i_size.  Fix this by not setting i_size
beyond the originally requested ending offset.

This bug was introduced by a22285a6 (2.6.35-rc1).
Signed-off-by: NSage Weil <sage@newdream.net>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

split_leaf was not properly balancing leaves when it was forced to
split a leaf twice.  This commit adds an extra push left and right
before forcing the double split in hopes of getting the slot where
we want to insert at either the start or end of the leaf.

If the extra pushes do work, then we are able to avoid splitting twice
and we keep the tree properly balanced.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This was just an odd wrapper around writeback_inodes_wb.  Removing this
also allows to get rid of the bdi member of struct writeback_control
which was rather out of place there.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

The "file" argument for fsync is never null so we can remove this check.

What drew my attention here is that 7ea80859: "drop unused dentry
argument to ->fsync" introduced an unconditional dereference at the
start of the function and that generated a smatch warning.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

posix_acl_from_xattr() returns both ERR_PTRs and null, but it's OK to
pass null values to set_cached_acl()
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

If btrfs_ioctl_snap_destroy() deletes a snapshot but finishes
with end_transaction(), the cleaner kthread may come in and
drop the root in the same transaction.  If that's the case, the
root's refs still == 1 in the tree when btrfs_del_root() deletes
the item, because commit_fs_roots() hasn't updated it yet (that
happens during the commit).

This wasn't a problem before only because
btrfs_ioctl_snap_destroy() would commit the transaction before dropping
the dentry reference, so the dead root wouldn't get queued up until
after the fs root item was updated in the btree.

Since it is not an error to drop the root reference and the root in the
same transaction, just drop the BUG_ON() in btrfs_del_root().
Signed-off-by: NSage Weil <sage@newdream.net>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

when used Posix File System Test Suite(pjd-fstest) to test btrfs,
some cases about setfacl failed when noacl mount option used.
I simplified used commands in pjd-fstest, and the following steps
can reproduce it.
------------------------
# cd btrfs-part/
# mkdir aaa
# setfacl -m m::rw aaa    <- successed, but not expected by pjd-fstest.
------------------------
I checked ext3, a warning message occured, like as:
  setfacl: aaa/: Operation not supported
Certainly, it's expected by pjd-fstest.

So, i compared acl.c of btrfs and ext3. Based on that, a patch created.
Fortunately, it works.
Signed-off-by: NShi Weihua <shiwh@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

On btrfs, do the following
------------------
# su user1
# cd btrfs-part/
# touch aaa
# getfacl aaa
  # file: aaa
  # owner: user1
  # group: user1
  user::rw-
  group::rw-
  other::r--
# su user2
# cd btrfs-part/
# setfacl -m u::rwx aaa
# getfacl aaa
  # file: aaa
  # owner: user1
  # group: user1
  user::rwx           <- successed to setfacl
  group::rw-
  other::r--
------------------
but we should prohibit it that user2 changing user1's acl.
In fact, on ext3 and other fs, a message occurs:
  setfacl: aaa: Operation not permitted

This patch fixed it.
Signed-off-by: NShi Weihua <shiwh@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

btrfs_lookup_dir_item() can return either ERR_PTRs or null.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

btrfs_read_fs_root_no_name() returns ERR_PTRs on error so I added a
check for that.  It's not clear to me if it can also return NULL
pointers or not so I left the original NULL pointer check as is.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This was added by a22285a6: "Btrfs: Integrate metadata reservation
with start_transaction".  If we goto out here then we skip all the
unwinding and there are locks still held etc.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

btrfs_iget() returns an ERR_PTR() on failure and not null.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Unwind and return -ENOMEM if the allocation fails here.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

If btrfs_lookup_dir_item() fails, we should can just let the mount fail
with an error.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Tree blocks can live in data block groups in FS converted from extN.
So it's easy to trigger the BUG_ON.
Signed-off-by: NYan Zheng <zheng.yan@oracle.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Fix a potential null dereference in relocation.c
Signed-off-by: NYan Zheng <zheng.yan@oracle.com>
Acked-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

when we use remap_file_pages() to remap a file, remap_file_pages always return
error. It is because btrfs didn't set VM_CAN_NONLINEAR for vma.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

refs can be used with uninitialized data if btrfs_lookup_extent_info()
fails on the first pass through the loop.  In the original code if that
happens then check_path_shared() probably returns 1, this patch
changes it to return 1 for safety.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Seems that when btrfs_fallocate was converted to use the new ENOSPC stuff we
dropped passing the mode to the function that actually does the preallocation.
This breaks anybody who wants to use FALLOC_FL_KEEP_SIZE.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

We cannot use the loop device which has been connected to a file in the btrf

The reproduce steps is following:
 # dd if=/dev/zero of=vdev0 bs=1M count=1024
 # losetup /dev/loop0 vdev0
 # mkfs.btrfs /dev/loop0
 ...
 failed to zero device start -5

The reason is that the btrfs don't implement either ->write_begin or ->write
the VFS API, so we fix it by setting ->write to do_sync_write().
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The ENOSPC code will now return ENOSPC to btrfs_start_transaction.
btrfs_dirty_inode needs to check for this and error out appropriately.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

In order to support DIO that isn't aligned to the filesystem blocksize,
we fall back to buffered for any unaligned DIOs.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Less printk is good printk.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

After the path is released, the generation number got from block
pointer is no long valid. The race may cause disk corruption, because
verify_parent_transid() calls clear_extent_buffer_uptodate() when
generation numbers mismatch.
Signed-off-by: NYan Zheng <zheng.yan@oracle.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

The O_DIRECT code wasn't checking for multiple references
on preallocated or nodatacow extents.  This means it
wasn't honoring snapshots properly.

The fix here is to add an explicit check for multiple references
This also fixes the math for selecting the correct disk block,
making sure not to go past the end of the extent.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

btrfs_dirty_inode tries to sneak in without much waiting or
space reservation, mostly for performance reasons.  This
usually works well but can cause problems when there are
many many writers.

When btrfs_update_inode fails with ENOSPC, we fallback
to a slower btrfs_start_transaction call that will reserve
some space.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This moves the delalloc space reservation done for O_DIRECT
into btrfs_direct_IO.  This way we don't leak reserved space
if the generic O_DIRECT write code errors out before it
calls into btrfs_direct_IO.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This changes O_DIRECT write code to mark extents as delalloc
while it is processing them.  Yan Zheng has reworked the
enospc accounting based on tracking delalloc extents and
this makes it much easier to track enospc in the O_DIRECT code.

There are a few space cases with the O_DIRECT code though,
it only sets the EXTENT_DELALLOC bits, instead of doing
EXTENT_DELALLOC | EXTENT_DIRTY | EXTENT_UPTODATE, because
we don't want to mess with clearing the dirty and uptodate
bits when things go wrong.  This is important because there
are no pages in the page cache, so any extent state structs
that we put in the tree won't get freed by releasepage.  We have
to clear them ourselves as the DIO ends.

With this commit, we reserve space at in btrfs_file_aio_write,
and then as each btrfs_direct_IO call progresses it sets
EXTENT_DELALLOC on the range.

btrfs_get_blocks_direct is responsible for clearing the delalloc
at the same time it drops the extent lock.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This adds:
  alias: devname:<name>
to some common kernel modules, which will allow the on-demand loading
of the kernel module when the device node is accessed.

Ideally all these modules would be compiled-in, but distros seems too
much in love with their modularization that we need to cover the common
cases with this new facility. It will allow us to remove a bunch of pretty
useless init scripts and modprobes from init scripts.

The static device node aliases will be carried in the module itself. The
program depmod will extract this information to a file in the module directory:
  $ cat /lib/modules/2.6.34-00650-g537b60d1-dirty/modules.devname
  # Device nodes to trigger on-demand module loading.
  microcode cpu/microcode c10:184
  fuse fuse c10:229
  ppp_generic ppp c108:0
  tun net/tun c10:200
  dm_mod mapper/control c10:235

Udev will pick up the depmod created file on startup and create all the
static device nodes which the kernel modules specify, so that these modules
get automatically loaded when the device node is accessed:
  $ /sbin/udevd --debug
  ...
  static_dev_create_from_modules: mknod '/dev/cpu/microcode' c10:184
  static_dev_create_from_modules: mknod '/dev/fuse' c10:229
  static_dev_create_from_modules: mknod '/dev/ppp' c108:0
  static_dev_create_from_modules: mknod '/dev/net/tun' c10:200
  static_dev_create_from_modules: mknod '/dev/mapper/control' c10:235
  udev_rules_apply_static_dev_perms: chmod '/dev/net/tun' 0666
  udev_rules_apply_static_dev_perms: chmod '/dev/fuse' 0666

A few device nodes are switched to statically allocated numbers, to allow
the static nodes to work. This might also useful for systems which still run
a plain static /dev, which is completely unsafe to use with any dynamic minor
numbers.

Note:
The devname aliases must be limited to the *common* and *single*instance*
device nodes, like the misc devices, and never be used for conceptually limited
systems like the loop devices, which should rather get fixed properly and get a
control node for losetup to talk to, instead of creating a random number of
device nodes in advance, regardless if they are ever used.

This facility is to hide the mess distros are creating with too modualized
kernels, and just to hide that these modules are not compiled-in, and not to
paper-over broken concepts. Thanks! :)

Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Alasdair G Kergon <agk@redhat.com>
Cc: Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
Cc: Ian Kent <raven@themaw.net>
Signed-Off-By: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The async helper threads offload crc work onto all the
CPUs, and make streaming writes much faster.  This
changes the O_DIRECT write code to use them.  The only
small complication was that we need to pass in the
logical offset in the file for each bio, because we can't
find it in the bio's pages.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Yan Zheng noticed two places we were doing a lot of work
without task->state set to TASK_RUNNING.  This sets the state
properly after we get ready to sleep but decide not to.
Signed-off-by: NChris Mason <chris.mason@oracle.com>