In these instances, we are trying to determine if a page has been accessed
since we began the operation for the sake of retry.  This is easily
accomplished by doing a gang lookup in the page mapping radix tree, and it
saves us the dependency on the flag (so that we might eventually delete
it).

btrfs_page_exists_in_range borrows heavily from find_get_page, replacing
the radix tree look up with a gang lookup of 1, so that we can find the
next highest page >= index and see if it falls into our lock range.
Signed-off-by: NChris Mason <clm@fb.com>
Signed-off-by: NAlex Gartrell <agartrell@fb.com>

This adds noinline_for_stack to two helpers used by
btree_write_cache_pages.  It shaves us down from 424 bytes on the
stack to 280.
Signed-off-by: NChris Mason <clm@fb.com>

__btrfs_write_out_cache was one of our stack pigs.  This breaks it
up into helper functions and slims it down to 194 bytes.
Signed-off-by: NChris Mason <clm@fb.com>

Memory leaks are bad mmkay?
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

I have an opinion that system logs /var/log/messages are
valuable info to investigate the real system issues at
the data center. People handling data center issues
do spend a lot time and efforts analyzing messages
files. Having usage error logged into /var/log/messages
is something we should avoid.
Signed-off-by: NAnand Jain <Anand.Jain@oracle.com>
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

I've noticed an extra line after "use no compression", but search
revealed much more in messages of more critical levels and rare errors.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

We need to NULL the cached_state after freeing it, otherwise
we might free it again if find_delalloc_range doesn't find anything.
Signed-off-by: NChris Mason <clm@fb.com>
cc: stable@vger.kernel.org

use the newer and more pleasant kstrtoull() to replace simple_strtoull(),
because simple_strtoull() is marked for obsoletion.
Signed-off-by: NZhang Zhen <zhenzhang.zhang@huawei.com>
Signed-off-by: NChris Mason <clm@fb.com>

Seeding device support allows us to create a new filesystem
based on existed filesystem.

However newly created filesystem's @total_devices should include seed
devices. This patch fix the following problem:

 # mkfs.btrfs -f /dev/sdb
 # btrfstune -S 1 /dev/sdb
 # mount /dev/sdb /mnt
 # btrfs device add -f /dev/sdc /mnt --->fs_devices->total_devices = 1
 # umount /mnt
 # mount /dev/sdc /mnt               --->fs_devices->total_devices = 2

This is because we record right @total_devices in superblock, but
@fs_devices->total_devices is reset to be 0 in btrfs_prepare_sprout().

Fix this problem by not resetting @fs_devices->total_devices.
Signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

Even CONFIG_BTRFS_FS_POSIX_ACL is not defined, the acl still could
been enabled using a mount option, and now fs/btrfs/acl.o is not
built, so the mount options will appear to be supported but will
be silently ignored.
Signed-off-by: NGuangliang Zhao <lucienchao@gmail.com>
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

This exercises the various parts of the new qgroup accounting code.  We do some
basic stuff and do some things with the shared refs to make sure all that code
works.  I had to add a bunch of infrastructure because I needed to be able to
insert items into a fake tree without having to do all the hard work myself,
hopefully this will be usefull in the future.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

Currently qgroups account for space by intercepting delayed ref updates to fs
trees.  It does this by adding sequence numbers to delayed ref updates so that
it can figure out how the tree looked before the update so we can adjust the
counters properly.  The problem with this is that it does not allow delayed refs
to be merged, so if you say are defragging an extent with 5k snapshots pointing
to it we will thrash the delayed ref lock because we need to go back and
manually merge these things together.  Instead we want to process quota changes
when we know they are going to happen, like when we first allocate an extent, we
free a reference for an extent, we add new references etc.  This patch
accomplishes this by only adding qgroup operations for real ref changes.  We
only modify the sequence number when we need to lookup roots for bytenrs, this
reduces the amount of churn on the sequence number and allows us to merge
delayed refs as we add them most of the time.  This patch encompasses a bunch of
architectural changes

1) qgroup ref operations: instead of tracking qgroup operations through the
delayed refs we simply add new ref operations whenever we notice that we need to
when we've modified the refs themselves.

2) tree mod seq:  we no longer have this separation of major/minor counters.
this makes the sequence number stuff much more sane and we can remove some
locking that was needed to protect the counter.

3) delayed ref seq: we now read the tree mod seq number and use that as our
sequence.  This means each new delayed ref doesn't have it's own unique sequence
number, rather whenever we go to lookup backrefs we inc the sequence number so
we can make sure to keep any new operations from screwing up our world view at
that given point.  This allows us to merge delayed refs during runtime.

With all of these changes the delayed ref stuff is a little saner and the qgroup
accounting stuff no longer goes negative in some cases like it was before.
Thanks,
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

According to commit 865ffef3
(fs: fix fsync() error reporting),
it's not stable to just check error pages because pages can be
truncated or invalidated, we should also mark mapping with error
flag so that a later fsync can catch the error.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NChris Mason <clm@fb.com>

Same as normal devices, seed devices should be initialized with
fs_info->dev_root as well, otherwise we'll get a NULL pointer crash.

Cc: Chris Murphy <lists@colorremedies.com>
Reported-by: NChris Murphy <lists@colorremedies.com>
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NChris Mason <clm@fb.com>

We hit something like the following function call flows:

|->run_delalloc_range()
 |->btrfs_join_transaction()
   |->cow_file_range()
     |->btrfs_join_transaction()
       |->find_free_extent()
         |->btrfs_join_transaction()

Trace infomation can be seen as:

[ 7411.127040] ------------[ cut here ]------------
[ 7411.127060] WARNING: CPU: 0 PID: 11557 at fs/btrfs/transaction.c:383 start_transaction+0x561/0x580 [btrfs]()
[ 7411.127079] CPU: 0 PID: 11557 Comm: kworker/u8:9 Tainted: G           O 3.13.0+ #4
[ 7411.127080] Hardware name: LENOVO QiTianM4350/ , BIOS F1KT52AUS 05/24/2013
[ 7411.127085] Workqueue: writeback bdi_writeback_workfn (flush-btrfs-5)
[ 7411.127092] Call Trace:
[ 7411.127097]  [<ffffffff815b87b0>] dump_stack+0x45/0x56
[ 7411.127101]  [<ffffffff81051ffd>] warn_slowpath_common+0x7d/0xa0
[ 7411.127102]  [<ffffffff810520da>] warn_slowpath_null+0x1a/0x20
[ 7411.127109]  [<ffffffffa0444fb1>] start_transaction+0x561/0x580 [btrfs]
[ 7411.127115]  [<ffffffffa0445027>] btrfs_join_transaction+0x17/0x20 [btrfs]
[ 7411.127120]  [<ffffffffa0431c91>] find_free_extent+0xa21/0xb50 [btrfs]
[ 7411.127126]  [<ffffffffa0431f68>] btrfs_reserve_extent+0xa8/0x1a0 [btrfs]
[ 7411.127131]  [<ffffffffa04322ce>] btrfs_alloc_free_block+0xee/0x440 [btrfs]
[ 7411.127137]  [<ffffffffa043bd6e>] ? btree_set_page_dirty+0xe/0x10 [btrfs]
[ 7411.127142]  [<ffffffffa041da51>] __btrfs_cow_block+0x121/0x530 [btrfs]
[ 7411.127146]  [<ffffffffa041dfff>] btrfs_cow_block+0x11f/0x1c0 [btrfs]
[ 7411.127151]  [<ffffffffa0421b74>] btrfs_search_slot+0x1d4/0x9c0 [btrfs]
[ 7411.127157]  [<ffffffffa0438567>] btrfs_lookup_file_extent+0x37/0x40 [btrfs]
[ 7411.127163]  [<ffffffffa0456bfc>] __btrfs_drop_extents+0x16c/0xd90 [btrfs]
[ 7411.127169]  [<ffffffffa0444ae3>] ? start_transaction+0x93/0x580 [btrfs]
[ 7411.127171]  [<ffffffff811663e2>] ? kmem_cache_alloc+0x132/0x140
[ 7411.127176]  [<ffffffffa041cd9a>] ? btrfs_alloc_path+0x1a/0x20 [btrfs]
[ 7411.127182]  [<ffffffffa044aa61>] cow_file_range_inline+0x181/0x2e0 [btrfs]
[ 7411.127187]  [<ffffffffa044aead>] cow_file_range+0x2ed/0x440 [btrfs]
[ 7411.127194]  [<ffffffffa0464d7f>] ? free_extent_buffer+0x4f/0xb0 [btrfs]
[ 7411.127200]  [<ffffffffa044b38f>] run_delalloc_nocow+0x38f/0xa60 [btrfs]
[ 7411.127207]  [<ffffffffa0461600>] ? test_range_bit+0x30/0x180 [btrfs]
[ 7411.127212]  [<ffffffffa044bd48>] run_delalloc_range+0x2e8/0x350 [btrfs]
[ 7411.127219]  [<ffffffffa04618f9>] ? find_lock_delalloc_range+0x1a9/0x1e0 [btrfs]
[ 7411.127222]  [<ffffffff812a1e71>] ? blk_queue_bio+0x2c1/0x330
[ 7411.127228]  [<ffffffffa0462ad4>] __extent_writepage+0x2f4/0x760 [btrfs]

Here we fix it by avoiding joining transaction again if we have held
a transaction handle when allocating chunk in find_free_extent().
Signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

To ease finding bugs during development related to modifying btree leaves
in such a way that it makes its items not sorted by key anymore. Since this
is an expensive check, it's only enabled if CONFIG_BTRFS_FS_CHECK_INTEGRITY
is set, which isn't meant to be enabled for regular users.
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

When the csum tree is empty, our leaf (path->nodes[0]) has a number
of items equal to 0 and since btrfs_header_nritems() returns an
unsigned integer (and so is our local nritems variable) the following
comparison always evaluates to false:

     if (path->slots[0] >= nritems - 1) {

As the casting rules lead to:

     if ((u32)0 >= (u32)4294967295) {

This makes us access key at slot paths->slots[0] + 1 (1) of the empty leaf
some lines below:

    btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
    if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
        found_key.type != BTRFS_EXTENT_CSUM_KEY) {
		found_next = 1;
		goto insert;
    }

So just don't access such non-existent slot and don't set found_next to 1
when the tree is empty. It's very unlikely we'll get a random key with the
objectid and type values above, which is where we could go into trouble.

If nritems is 0, just set found_next to 1 anyway as it will make us insert
a csum item covering our whole extent (or the whole leaf) when the tree is
empty.
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: NChris Mason <clm@fb.com>

In close_ctree(), after we have stopped all workers,there maybe still
some read requests(for example readahead) to submit and this *maybe* trigger
an oops that user reported before:

kernel BUG at fs/btrfs/async-thread.c:619!

By hacking codes, i can reproduce this problem with one cpu available.
We fix this potential problem by invalidating all btree inode pages before
stopping all workers.

Thanks to Miao for pointing out this problem.
Signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

In btrfs_create_tree(), if btrfs_insert_root() fails, we should
free root->commit_root.
Reported-by: NAlex Lyakas <alex@zadarastorage.com>
Signed-off-by: NTsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

posix_acl_xattr_set() already does the check, and it's the only
way to feed in an ACL from userspace.
So the check here is useless, remove it.
Signed-off-by: Nzhang zhen <zhenzhang.zhang@huawei.com>
Signed-off-by: NChris Mason <clm@fb.com>

This fix will ensure all SB copies on the disk is zeroed
when the disk is intentionally removed. This helps to
better manage disks in the user land.

This version of patch also merges the Zach patch as below.

 btrfs: don't double brelse on device rm
Signed-off-by: NAnand Jain <anand.jain@oracle.com>
Signed-off-by: NZach Brown <zab@redhat.com>
Signed-off-by: NChris Mason <clm@fb.com>

Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

This is a continuation of the previous changes titled:

   Btrfs: fix incremental send's decision to delay a dir move/rename
   Btrfs: part 2, fix incremental send's decision to delay a dir move/rename

There's a few more cases where a directory rename/move must be delayed which was
previously overlooked. If our immediate ancestor has a lower inode number than
ours and it doesn't have a delayed rename/move operation associated to it, it
doesn't mean there isn't any non-direct ancestor of our current inode that needs
to be renamed/moved before our current inode (i.e. with a higher inode number
than ours).

So we can't stop the search if our immediate ancestor has a lower inode number than
ours, we need to navigate the directory hierarchy upwards until we hit the root or:

1) find an ancestor with an higher inode number that was renamed/moved in the send
   root too (or already has a pending rename/move registered);
2) find an ancestor that is a new directory (higher inode number than ours and
   exists only in the send root).

Reproducer for case 1)

    $ mkfs.btrfs -f /dev/sdd
    $ mount /dev/sdd /mnt

    $ mkdir -p /mnt/a/b
    $ mkdir -p /mnt/a/c/d
    $ mkdir /mnt/a/b/e
    $ mkdir /mnt/a/c/d/f
    $ mv /mnt/a/b /mnt/a/c/d/2b
    $ mkdir /mnt/a/x
    $ mkdir /mnt/a/y

    $ btrfs subvolume snapshot -r /mnt /mnt/snap1
    $ btrfs send /mnt/snap1 -f /tmp/base.send

    $ mv /mnt/a/x /mnt/a/y
    $ mv /mnt/a/c/d/2b/e /mnt/a/c/d/2b/2e
    $ mv /mnt/a/c/d /mnt/a/h/2d
    $ mv /mnt/a/c /mnt/a/h/2d/2b/2c

    $ btrfs subvolume snapshot -r /mnt /mnt/snap2
    $ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/incremental.send

Simple reproducer for case 2)

    $ mkfs.btrfs -f /dev/sdd
    $ mount /dev/sdd /mnt

    $ mkdir -p /mnt/a/b
    $ mkdir /mnt/a/c
    $ mv /mnt/a/b /mnt/a/c/b2
    $ mkdir /mnt/a/e

    $ btrfs subvolume snapshot -r /mnt /mnt/snap1
    $ btrfs send /mnt/snap1 -f /tmp/base.send

    $ mv /mnt/a/c/b2 /mnt/a/e/b3
    $ mkdir /mnt/a/e/b3/f
    $ mkdir /mnt/a/h
    $ mv /mnt/a/c /mnt/a/e/b3/f/c2
    $ mv /mnt/a/e /mnt/a/h/e2

    $ btrfs subvolume snapshot -r /mnt /mnt/snap2
    $ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/incremental.send

Another simple reproducer for case 2)

    $ mkfs.btrfs -f /dev/sdd
    $ mount /dev/sdd /mnt

    $ mkdir -p /mnt/a/b
    $ mkdir /mnt/a/c
    $ mkdir /mnt/a/b/d
    $ mkdir /mnt/a/c/e

    $ btrfs subvolume snapshot -r /mnt /mnt/snap1
    $ btrfs send /mnt/snap1 -f /tmp/base.send

    $ mkdir /mnt/a/b/d/f
    $ mkdir /mnt/a/b/g
    $ mv /mnt/a/c/e /mnt/a/b/g/e2
    $ mv /mnt/a/c /mnt/a/b/d/f/c2
    $ mv /mnt/a/b/d/f /mnt/a/b/g/e2/f2

    $ btrfs subvolume snapshot -r /mnt /mnt/snap2
    $ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/incremental.send

More complex reproducer for case 2)

    $ mkfs.btrfs -f /dev/sdd
    $ mount /dev/sdd /mnt

    $ mkdir -p /mnt/a/b
    $ mkdir -p /mnt/a/c/d
    $ mkdir /mnt/a/b/e
    $ mkdir /mnt/a/c/d/f
    $ mv /mnt/a/b /mnt/a/c/d/2b
    $ mkdir /mnt/a/x
    $ mkdir /mnt/a/y

    $ btrfs subvolume snapshot -r /mnt /mnt/snap1
    $ btrfs send /mnt/snap1 -f /tmp/base.send

    $ mv /mnt/a/x /mnt/a/y
    $ mv /mnt/a/c/d/2b/e /mnt/a/c/d/2b/2e
    $ mv /mnt/a/c/d /mnt/a/h/2d
    $ mv /mnt/a/c /mnt/a/h/2d/2b/2c

    $ btrfs subvolume snapshot -r /mnt /mnt/snap2
    $ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/incremental.send

For both cases the incremental send would enter an infinite loop when building
path strings.

While solving these cases, this change also re-implements the code to detect
when directory moves/renames should be delayed. Instead of dealing with several
specific cases separately, it's now more generic handling all cases with a simple
detection algorithm and if when applying a delayed move/rename there's a path loop
detected, it further delays the move/rename registering a new ancestor inode as
the dependency inode (so our rename happens after that ancestor is renamed).

Tests for these cases is being added to xfstests too.
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: NChris Mason <clm@fb.com>

Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: NChris Mason <clm@fb.com>

If we have directories with a pending move/rename operation, we must take into
account any orphan directories that got created before executing the pending
move/rename. Those orphan directories are directories with an inode number higher
then the current send progress and that don't exist in the parent snapshot, they
are created before current progress reaches their inode number, with a generated
name of the form oN-M-I and at the root of the filesystem tree, and later when
progress matches their inode number, moved/renamed to their final location.

Reproducer:

          $ mkfs.btrfs -f /dev/sdd
          $ mount /dev/sdd /mnt

          $ mkdir -p /mnt/a/b/c/d
          $ mkdir /mnt/a/b/e
          $ mv /mnt/a/b/c /mnt/a/b/e/CC
          $ mkdir /mnt/a/b/e/CC/d/f
	  $ mkdir /mnt/a/g

          $ btrfs subvolume snapshot -r /mnt /mnt/snap1
          $ btrfs send /mnt/snap1 -f /tmp/base.send

          $ mkdir /mnt/a/g/h
	  $ mv /mnt/a/b/e /mnt/a/g/h/EE
          $ mv /mnt/a/g/h/EE/CC/d /mnt/a/g/h/EE/DD

          $ btrfs subvolume snapshot -r /mnt /mnt/snap2
          $ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/incremental.send

The second receive command failed with the following error:

    ERROR: rename a/b/e/CC/d -> o264-7-0/EE/DD failed. No such file or directory

A test case for xfstests follows soon.
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: NChris Mason <clm@fb.com>

Regardless of whether the caller is interested or not in knowing the inode's
generation (dir_gen != NULL), get_first_ref always does a btree lookup to get
the inode item. Avoid this useless lookup if dir_gen parameter is NULL (which
is in some cases).
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: NChris Mason <clm@fb.com>

For RAID0,5,6,10,
For system chunk, there shouldn't be too many stripes to
make a btrfs_chunk that exceeds BTRFS_SYSTEM_CHUNK_ARRAY_SIZE
For data/meta chunk, there shouldn't be too many stripes to
make a btrfs_chunk that exceeds a leaf.
Signed-off-by: NGui Hecheng <guihc.fnst@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

For system chunk array,
We copy a "disk_key" and an chunk item each time,
so there should be enough space to hold both of them,
not only the chunk item.
Signed-off-by: NGui Hecheng <guihc.fnst@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

Current btrfs_orphan_cleanup will also cleanup roots which is already in
fs_info->dead_roots without protection.
This will have conditional race with fs_info->cleaner_kthread.

This patch will use refs in root->root_item to detect roots in
dead_roots and avoid conflicts.
Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

Before applying this patch, the task had to reclaim the metadata space
by itself if the metadata space was not enough. And When the task started
the space reclamation, all the other tasks which wanted to reserve the
metadata space were blocked. At some cases, they would be blocked for
a long time, it made the performance fluctuate wildly.

So we introduce the background metadata space reclamation, when the space
is about to be exhausted, we insert a reclaim work into the workqueue, the
worker of the workqueue helps us to reclaim the reserved space at the
background. By this way, the tasks needn't reclaim the space by themselves at
most cases, and even if the tasks have to reclaim the space or are blocked
for the space reclamation, they will get enough space more quickly.

Here is my test result(Tested by compilebench):
 Memory:	2GB
 CPU:		2Cores * 1CPU
 Partition:	40GB(SSD)

Test command:
 # compilebench -D <mnt> -m

Without this patch:
 intial create total runs 30 avg 54.36 MB/s (user 0.52s sys 2.44s)
 compile total runs 30 avg 123.72 MB/s (user 0.13s sys 1.17s)
 read compiled tree total runs 3 avg 81.15 MB/s (user 0.74s sys 4.89s)
 delete compiled tree total runs 30 avg 5.32 seconds (user 0.35s sys 4.37s)

With this patch:
 intial create total runs 30 avg 59.80 MB/s (user 0.52s sys 2.53s)
 compile total runs 30 avg 151.44 MB/s (user 0.13s sys 1.11s)
 read compiled tree total runs 3 avg 83.25 MB/s (user 0.76s sys 4.91s)
 delete compiled tree total runs 30 avg 5.29 seconds (user 0.34s sys 4.34s)
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

If we fail to load a free space cache, we can rebuild it from the extent tree,
so it is not a serious error, we should not output a error message that
would make the users uncomfortable. This patch uses warning message instead
of it.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

Btrfs will send uevent to udev inform the device change,
but ctime/mtime for the block device inode is not udpated, which cause
libblkid used by btrfs-progs unable to detect device change and use old
cache, causing 'btrfs dev scan; btrfs dev rmove; btrfs dev scan' give an
error message.
Reported-by: NTsutomu Itoh <t-itoh@jp.fujitsu.com>
Cc: Karel Zak <kzak@redhat.com>
Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

CC: Miao Xie <miaox@cn.fujitsu.com>
CC: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

The patch "Btrfs: fix protection between send and root deletion"
(18f687d5) does not actually prevent to delete the snapshot
and just takes care during background cleaning, but this seems rather
user unfriendly, this patch implements the idea presented in

http://www.spinics.net/lists/linux-btrfs/msg30813.html

- add an internal root_item flag to denote a dead root
- check if the send_in_progress is set and refuse to delete, otherwise
  set the flag and proceed
- check the flag in send similar to the btrfs_root_readonly checks, for
  all involved roots

The root lookup in send via btrfs_read_fs_root_no_name will check if the
root is really dead or not. If it is, ENOENT, aborted send. If it's
alive, it's protected by send_in_progress, send can continue.

CC: Miao Xie <miaox@cn.fujitsu.com>
CC: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

It doesn't need to check NULL for kfree()
Signed-off-by: NDaeseok Youn <daeseok.youn@gmail.com>
Signed-off-by: NChris Mason <clm@fb.com>

This implements the tmpfile callback of struct inode_operations, introduced
in the linux kernel 3.11, and implemented already by some filesystems. This
callback is invoked by the VFS when the flag O_TMPFILE is passed to the open
system call.
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: NChris Mason <clm@fb.com>
Reviewed-by: NDavid Sterba <dsterba@suse.cz>

This ioctl provides basic info about the filesystem that can be obtained
in other ways (eg. sysfs), there's no reason to restrict it to
CAP_SYSADMIN.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

This ioctl provides basic info about the devices that can be obtained in
other ways (eg. sysfs), there's no reason to restrict it to
CAP_SYSADMIN.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>