This has been resulting in a BUT_ON(ret) after btrfs_reserve_extent in
btrfs_cow_file_range.  The reason is we don't actually calculate the bytes_super
for a block group until we go to cache it, which means that the space_info can
hand out reservations for space that it doesn't actually have, and we can run
out of data space.  This is also a problem if you are using space caching since
we don't ever calculate bytes_super for the block groups.  So instead everytime
we read a block group call exclude_super_stripes, which calculates the
bytes_super for the block group so it can be left out of the space_info.  Then
whenever caching completes we just call free_excluded_extents so that the super
excluded extents are freed up.  Also if we are unmounting and we hit any block
groups that haven't been cached we still need to call free_excluded_extents to
make sure things are cleaned up properly.  Thanks,
Reported-by: NArne Jansen <sensille@gmx.net>
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

When we're cleaning up the tree log we need to be able to remove free space from
the block group.  The problem is if that free space spans bitmaps we would not
find the space since we're looking for too many bytes.  So make sure the amount
of bytes we search for is limited to either the number of bytes we want, or the
number of bytes left in the bitmap.  This was tested by a user who was hitting
the BUG() after search_bitmap.  With this patch he can now mount his fs.
Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

The error check of btrfs_start_transaction() is added, and the mistake
of the error check on several places is corrected.
Signed-off-by: NTsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Because NULL is returned when the memory allocation fails,
it is checked whether it is NULL.
Signed-off-by: NTsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This one isn't really an uninit variable, but for pretty
obscure reasons.  Let's make it clearly correct.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

btrfs_sync_log returns -EAGAIN when we need full transaction commits
instead of small log commits, but sometimes we were dropping the return
value.

In practice, we check for this a few different ways, but this is still a
bug that can leave off full log commits when we really need them.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Xfstests 224 will just sit there and spin for ever until eventually we give up
flushing delalloc and exit.  On my box this took several hours.  I could not
interrupt this process either, even though we use INTERRUPTIBLE.  So do 2 things

1) Keep us from looping over and over again without reclaiming anything
2) If we get interrupted exit the loop

I tested this and the test now exits in a reasonable amount of time, and can be
interrupted with ctrl+c.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Instead of doing a BUG_ON(1) in prepare_pages if grab_cache_page() fails, just
loop through the pages we've already grabbed and unlock and release them, then
return -ENOMEM like we should.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Got a report of a box panicing because we got a NULL eb in read_extent_buffer.
His fs was borked and btrfs_search_path returned EIO, but we don't check for
errors so the box paniced.  Yes I know this will just make something higher up
the stack panic, but that's a problem for future Josef.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

We call use_block_rsv right before we make an allocation in order to make sure
we have enough space.  Now normally people have called btrfs_start_transaction()
with the appropriate amount of space that we need, so we just use some of that
pre-reserved space and move along happily.  The problem is where people use
btrfs_join_transaction(), which doesn't actually reserve any space.  So we try
and reserve space here, but we cannot flush delalloc, so this forces us to
return -ENOSPC when in reality we have plenty of space.  The most common symptom
is seeing a bunch of "couldn't dirty inode" messages in syslog.  With
xfstests 224 we end up falling back to start_transaction and then doing all the
flush delalloc stuff which causes to hang for a very long time.

So instead steal from the global reserve, which is what this is meant for
anyway.  With this patch and the other 2 I have sent xfstests 224 now passes
successfully.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

When we do btrfs_block_rsv_release, if global_block_rsv is not full we will
release all the extra bytes to global_block_rsv, even if it's only a little
short of the amount of space that we need to reserve.  This causes us to starve
ourselves of reservable space during the transaction which will force us to
shrink delalloc bytes and commit the transaction more often than we should.  So
instead just add the amount of bytes we need to add to the global reserve so
reserved == size, and then add the rest back into the space_info for general
use.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

When running xfstests 224 I kept getting ENOSPC when trying to remove the files,
and this is because we were returning ret from check_path_shared while it was
uninitalized, which isn't right.  Fix this to return 0 properly, and now
xfstests 224 doesn't freak out when it tries to clean itself up.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

btrfs_start_ioctl_transaction() returns ERR_PTR(), not NULL.
So, it is necessary to use IS_ERR() to check the return value.
Signed-off-by: NTsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

The error check of btrfs_join_transaction()/btrfs_join_transaction_nolock()
is added, and the mistake of the error check in several places is
corrected.

For more stable Btrfs, I think that we should reduce BUG_ON().
But, I think that long time is necessary for this.
So, I propose this patch as a short-term solution.

With this patch:
 - To more stable Btrfs, the part that should be corrected is clarified.
 - The panic isn't done by the NULL pointer reference etc. (even if
   BUG_ON() is increased temporarily)
 - The error code is returned in the place where the error can be easily
   returned.

As a long-term plan:
 - BUG_ON() is reduced by using the forced-readonly framework, etc.
Signed-off-by: NTsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

After the conditional that precedes the following code, inode may be an
ERR_PTR value.  This can eg result from a memory allocation failure via the
call to btrfs_iget, and thus does not imply that root is different than
sub_root.  Thus, an IS_ERR check is added to ensure that there is no
dereference of inode in this case.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r@
identifier f;
@@
f(...) { ... return ERR_PTR(...); }

@@
identifier r.f, fld;
expression x;
statement S1,S2;
@@
 x = f(...)
 ... when != IS_ERR(x)
(
 if (IS_ERR(x) ||...) S1 else S2
|
*x->fld
)
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

There is a missing break in switch, fix it.
Signed-off-by: NLiu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

To make btrfs more stable, add several missing necessary memory allocation
checks, and when no memory, return proper errno.

We've checked that some of those -ENOMEM errors will be returned to
userspace, and some will be catched by BUG_ON() in the upper callers,
and none will be ignored silently.
Signed-off-by: NLiu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

btrfs_submit_compressed_read() is lack of memory allocation checks and
corresponding error route.

After this fix, if it comes to "no memory" case, errno will be returned
to userland step by step, and tell users this operation cannot go on.
Signed-off-by: NLiu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

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: NLi 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: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NLi 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: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>

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

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

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

Remove some duplicated code.

This prepares for the next patch.
Reviewed-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NLi 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: NJosef Bacik <josef@redhat.com>
Signed-off-by: NLi 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: NLiu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: NChris 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: NAron Xu <happyaron.xu@gmail.com>
Signed-off-by: NBen Hutchings <ben@decadent.org.uk>
Signed-off-by: NChris 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: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris 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: NTsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Should check if functions returns NULL or not.
Signed-off-by: NTsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: NChris 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: NJesper Juhl <jj@chaosbits.net>
Signed-off-by: NChris 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: NDave Young <hidave.darkstar@gmail.com>
Signed-off-by: NChris 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: NJesper Juhl <jj@chaosbits.net>
Signed-off-by: NChris 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: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>