Suppose:
- the source extent is: [0, 100]
- the src offset is 10
- the clone length is 90
- the dest offset is 0

This statement:

	new_key.offset = key.offset + destoff - off

will produce such an extent for the dest file:

	[ino, BTRFS_EXTENT_DATA_KEY, -10]

, which is obviously wrong.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

fixup, which is allocated when starting page write to fix up the
extent without ORDERED bit set, should be freed after this work
is done.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

Steps to reproduce:

  # mkfs.btrfs /dev/sda2
  # mount /dev/sda2 /mnt
  # touch /mnt/file0
  # setfacl -m 'u:root:x,g::x,o::x' /mnt/file0
  # umount /mnt
  # mount /dev/sda2 -o noacl /mnt
  # getfacl /mnt/file0
  ...
  user::rw-
  user:root:--x
  group::--x
  mask::--x
  other::--x

The output should be:

  user::rw-
  group::--x
  other::--x
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

We must save and free the original kstrdup()'ed pointer
because strsep() modifies its first argument.
Signed-off-by: Tero Roponen <tero.roponen@gmail.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

We missed a memory deallocation in commit 450ba0ea.

If an existing super block is found at mount and there is no
error condition then the pre-allocated tree_root and fs_info
are no not used and are not freeded.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

fs_info, which is allocated in open_ctree(), should be freed
in close_ctree().
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

After returing extents from a cluster to the block group, some
extents in the block group may be mergeable.
Reviewed-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

When adding a new extent, we'll firstly see if we can merge
this extent to the left or/and right extent. Extract this as
a helper try_merge_free_space().

As a side effect, we fix a small bug that if the new extent
has non-bitmap left entry but is unmergeble, we'll directly
link the extent without trying to drop it into bitmap.

This also prepares for the next patch.
Reviewed-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

When allocating extent entry from a cluster, we should update
the free_space and free_extents fields of the block group.
Reviewed-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

If there's no more free space in a bitmap, we should free it.
Reviewed-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

Remove some duplicated code.

This prepares for the next patch.
Reviewed-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

If a block group is smaller than 1GB, the extent entry threadhold
calculation will always set the threshold to 0.

So as free space gets fragmented, btrfs will switch to use bitmap
to manage free space, but then will never switch back to extents
due to this bug.
Reviewed-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

This patch comes from "Forced readonly mounts on errors" ideas.

As we know, this is the first step in being more fault tolerant of disk
corruptions instead of just using BUG() statements.

The major content:
- add a framework for generating errors that should result in filesystems
  going readonly.
- keep FS state in disk super block.
- make sure that all of resource will be freed and released at umount time.
- make sure that fter FS is forced readonly on error, there will be no more
  disk change before FS is corrected. For this, we should stop write operation.

After this patch is applied, the conversion from BUG() to such a framework can
happen incrementally.
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

Filesystem rebalancing (BTRFS_IOC_BALANCE) affects the entire
filesystem and may run uninterruptibly for a long time.  This does not
seem to be something that an unprivileged user should be able to do.
Reported-by: Aron Xu <happyaron.xu@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

If we run low on space we could get a bunch of warnings out of
btrfs_block_rsv_check, but this is mostly just called via the transaction code
to see if we need to end the transaction, it expects to see failures, so let's
not WARN and freak everybody out for no reason.  Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

In btrfs_read_fs_root_no_radix(), 'root' is not freed if
btrfs_search_slot() returns error.
Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

Should check if functions returns NULL or not.
Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

Hi,

In fs/btrfs/inode.c::fixup_tree_root_location() we have this code:

...
 		if (!path) {
 			err = -ENOMEM;
 			goto out;
 		}
...
 	out:
 		btrfs_free_path(path);
 		return err;

btrfs_free_path() passes its argument on to other functions and some of
them end up dereferencing the pointer.
In the code above that pointer is clearly NULL, so btrfs_free_path() will
eventually cause a NULL dereference.

There are many ways to cut this cake (fix the bug). The one I chose was to
make btrfs_free_path() deal gracefully with NULL pointers. If you
disagree, feel free to come up with an alternative patch.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

I happened to pass swap partition as root partition in cmdline,
then kernel panic and tell me about "Cannot open root device".
It is not correct, in fact it is a fs type mismatch instead of 'no device'.

Eventually I found btrfs mounting failed with -EIO, it should be -EINVAL.
The logic in init/do_mounts.c:
        for (p = fs_names; *p; p += strlen(p)+1) {
                int err = do_mount_root(name, p, flags, root_mount_data);
                switch (err) {
                        case 0:
                                goto out;
                        case -EACCES:
                                flags |= MS_RDONLY;
                                goto retry;
                        case -EINVAL:
                                continue;
                }
		print "Cannot open root device"
		panic
	}
SO fs type after btrfs will have no chance to mount

Here fix the return value as -EINVAL
Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

It seems to me that we leak the memory allocated to 'value' in
btrfs_get_acl() if the call to posix_acl_from_xattr() fails.
Here's a patch that attempts to correct that problem.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

When we store data by raid profile in btrfs with two or more different size
disks, df command shows there is some free space in the filesystem, but the
user can not write any data in fact, df command shows the wrong free space
information of btrfs.

 # mkfs.btrfs -d raid1 /dev/sda9 /dev/sda10
 # btrfs-show
 Label: none  uuid: a95cd49e-6e33-45b8-8741-a36153ce4b64
 	Total devices 2 FS bytes used 28.00KB
 	devid    1 size 5.01GB used 2.03GB path /dev/sda9
 	devid    2 size 10.00GB used 2.01GB path /dev/sda10
 # btrfs device scan /dev/sda9 /dev/sda10
 # mount /dev/sda9 /mnt
 # dd if=/dev/zero of=tmpfile0 bs=4K count=9999999999
   (fill the filesystem)
 # sync
 # df -TH
 Filesystem	Type	Size	Used	Avail	Use%	Mounted on
 /dev/sda9	btrfs	17G	8.6G	5.4G	62%	/mnt
 # btrfs-show
 Label: none  uuid: a95cd49e-6e33-45b8-8741-a36153ce4b64
 	Total devices 2 FS bytes used 3.99GB
 	devid    1 size 5.01GB used 5.01GB path /dev/sda9
 	devid    2 size 10.00GB used 4.99GB path /dev/sda10

It is because btrfs cannot allocate chunks when one of the pairing disks has
no space, the free space on the other disks can not be used for ever, and should
be subtracted from the total space, but btrfs doesn't subtract this space from
the total. It is strange to the user.

This patch fixes it by calcing the free space that can be used to allocate
chunks.

Implementation:
1. get all the devices free space, and align them by stripe length.
2. sort the devices by the free space.
3. check the free space of the devices,
   3.1. if it is not zero, and then check the number of the devices that has
        more free space than this device,
        if the number of the devices is beyond the min stripe number, the free
        space can be used, and add into total free space.
        if the number of the devices is below the min stripe number, we can not
        use the free space, the check ends.
   3.2. if the free space is zero, check the next devices, goto 3.1

This implementation is just likely fake chunk allocation.

After appling this patch, df can show correct space information:
 # df -TH
 Filesystem	Type	Size	Used	Avail	Use%	Mounted on
 /dev/sda9	btrfs	17G	8.6G	0	100%	/mnt
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

With this patch, we change the handling method when we can not get enough free
extents with default size.

Implementation:
1. Look up the suitable free extent on each device and keep the search result.
   If not find a suitable free extent, keep the max free extent
2. If we get enough suitable free extents with default size, chunk allocation
   succeeds.
3. If we can not get enough free extents, but the number of the extent with
   default size is >= min_stripes, we just change the mapping information
   (reduce the number of stripes in the extent map), and chunk allocation
   succeeds.
4. If the number of the extent with default size is < min_stripes, sort the
   devices by its max free extent's size descending
5. Use the size of the max free extent on the (num_stripes - 1)th device as the
   stripe size to allocate the device space

By this way, the chunk allocator can allocate chunks as large as possible when
the devices' space is not enough and make full use of the devices.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

- make it return the start position and length of the max free space when it can
  not find a suitable free space.
- make it more readability
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

There are two tiny problem:
- One is When we check the chunk size is greater than the max chunk size or not,
  we should take mirrors into account, but the original code didn't.
- The other is btrfs shouldn't use the size of the residual free space as the
  length of of a dup chunk when doing chunk allocation. It is because the device
  space that a dup chunk needs is twice as large as the chunk size, if we use
  the size of the residual free space as the length of a dup chunk, we can not
  get enough free space. Fix it.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Reviewed-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

We cannot write data into files when when there is tiny space in the filesystem.

Reproduce steps:
 # mkfs.btrfs /dev/sda1
 # mount /dev/sda1 /mnt
 # dd if=/dev/zero of=/mnt/tmpfile0 bs=4K count=1
 # dd if=/dev/zero of=/mnt/tmpfile1 bs=4K count=99999999999999
   (fill the filesystem)
 # umount /mnt
 # mount /dev/sda1 /mnt
 # rm -f /mnt/tmpfile0
 # dd if=/dev/zero of=/mnt/tmpfile0 bs=4K count=1
   (failed with nospec)

But if we do the last step again, we can write data successfully. The reason of
the problem is that btrfs didn't try to commit the current transaction and
reclaim some space when chunk allocation failed.

This patch fixes it by committing the current transaction to reclaim some
space when chunk allocation fails.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Reviewed-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

Josef has implemented mixed data/metadata chunks, we must add those chunks'
space just like data chunks.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Reviewed-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

CC [M]  fs/btrfs/ctree.o
In file included from fs/btrfs/ctree.c:21:0:
fs/btrfs/ctree.h:1003:17: error: field <91>super_kobj<92> has incomplete type
fs/btrfs/ctree.h:1074:17: error: field <91>root_kobj<92> has incomplete type
make[2]: *** [fs/btrfs/ctree.o] Error 1
make[1]: *** [fs/btrfs] Error 2
make: *** [fs] Error 2

We need to include kobject.h here.
Reported-by: Jeff Garzik <jeff@garzik.org>
Fix-suggested-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

When we read in block groups, we'll set non-redundant groups
readonly if we find a raid1, DUP or raid10 group.  But the
ro code has an off by one bug in the math around testing to
make sure out accounting doesn't go wrong.
Signed-off-by: Chris Mason <chris.mason@oracle.com>

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: Li 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: Li Zefan <lizf@cn.fujitsu.com>

Split it into two functions for two different ioctls, since they
share no common code.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

Add a common function to copy decompressed data from working buffer
to bio pages.
Signed-off-by: Li 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: Li Zefan <lizf@cn.fujitsu.com>

Lzo is a much faster compression algorithm than gzib, so would allow
more users to enable transparent compression, and some users can
choose from compression ratio and speed for different applications

Usage:

 # mount -t btrfs -o compress[=<zlib,lzo>] dev /mnt
or
 # mount -t btrfs -o compress-force[=<zlib,lzo>] dev /mnt

"-o compress" without argument is still allowed for compatability.

Compatibility:

If we mount a filesystem with lzo compression, it will not be able be
mounted in old kernels. One reason is, otherwise btrfs will directly
dump compressed data, which sits in inline extent, to user.

Performance:

The test copied a linux source tarball (~400M) from an ext4 partition
to the btrfs partition, and then extracted it.

(time in second)
           lzo        zlib        nocompress
copy:      10.6       21.7        14.9
extract:   70.1       94.4        66.6

(data size in MB)
           lzo        zlib        nocompress
copy:      185.87     108.69      394.49
extract:   193.80     132.36      381.21

Changelog:

v1 -> v2:
- Select LZO_COMPRESS and LZO_DECOMPRESS in btrfs Kconfig.
- Add incompability flag.
- Fix error handling in compress code.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

Make the code aware of compression type, instead of always assuming
zlib compression.

Also make the zlib workspace function as common code for all
compression types.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

Return failure if alloc_page() fails to allocate memory,
and the upper code will just give up compression.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

- Fix a race that can result in alloc_workspace > cpus.
- Fix to check num_workspace after wakeup.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>