It can avoid complex calculation of real stripes in sort,
moreover, we can clean up code of sorting tgtdev_map because it
will be in order initially.
Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Finally it's clear that the requested blocksize is always equal to
nodesize, with one exception, the superblock.

Superblock has fixed size regardless of the metadata block size, but
uses the same helpers to initialize sys array/chunk tree and to work
with the chunk items. So it pretends to be an extent_buffer for a
moment, btrfs_read_sys_array is full of special cases, we're adding one
more.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>

On chunk allocation error (label "error_del_extent"), after adding the
extent map to the tree and to the pending chunks list, we would leave
decrementing the extent map's refcount by 2 instead of 3 (our allocation
+ tree reference + list reference).

Also, on chunk/block group removal, if the block group was on the list
pending_chunks we weren't decrementing the respective list reference.

Detected by 'rmmod btrfs':

[20770.105881] kmem_cache_destroy btrfs_extent_map: Slab cache still has objects
[20770.106127] CPU: 2 PID: 11093 Comm: rmmod Tainted: G        W    L 3.17.0-rc5-btrfs-next-1+ #1
[20770.106128] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
[20770.106130]  0000000000000000 ffff8800ba867eb8 ffffffff813e7a13 ffff8800a2e11040
[20770.106132]  ffff8800ba867ed0 ffffffff81105d0c 0000000000000000 ffff8800ba867ee0
[20770.106134]  ffffffffa035d65e ffff8800ba867ef0 ffffffffa03b0654 ffff8800ba867f78
[20770.106136] Call Trace:
[20770.106142]  [<ffffffff813e7a13>] dump_stack+0x45/0x56
[20770.106145]  [<ffffffff81105d0c>] kmem_cache_destroy+0x4b/0x90
[20770.106164]  [<ffffffffa035d65e>] extent_map_exit+0x1a/0x1c [btrfs]
[20770.106176]  [<ffffffffa03b0654>] exit_btrfs_fs+0x27/0x9d3 [btrfs]
[20770.106179]  [<ffffffff8109dc97>] SyS_delete_module+0x153/0x1c4
[20770.106182]  [<ffffffff8121261b>] ? trace_hardirqs_on_thunk+0x3a/0x3c
[20770.106184]  [<ffffffff813ebf52>] system_call_fastpath+0x16/0x1b

This applies on top (depends on) of my previous patch titled:
"Btrfs: fix race between fs trimming and block group remove/allocation"

But the issue in fact was already present before that change, it only
became easier to hit after Josef's 3.18 patch that added automatic
removal of empty block groups.
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NChris Mason <clm@fb.com>

Our fs trim operation, which is completely transactionless (doesn't start
or joins an existing transaction) consists of visiting all block groups
and then for each one to iterate its free space entries and perform a
discard operation against the space range represented by the free space
entries. However before performing a discard, the corresponding free space
entry is removed from the free space rbtree, and when the discard completes
it is added back to the free space rbtree.

If a block group remove operation happens while the discard is ongoing (or
before it starts and after a free space entry is hidden), we end up not
waiting for the discard to complete, remove the extent map that maps
logical address to physical addresses and the corresponding chunk metadata
from the the chunk and device trees. After that and before the discard
completes, the current running transaction can finish and a new one start,
allowing for new block groups that map to the same physical addresses to
be allocated and written to.

So fix this by keeping the extent map in memory until the discard completes
so that the same physical addresses aren't reused before it completes.

If the physical locations that are under a discard operation end up being
used for a new metadata block group for example, and dirty metadata extents
are written before the discard finishes (the VM might call writepages() of
our btree inode's i_mapping for example, or an fsync log commit happens) we
end up overwriting metadata with zeroes, which leads to errors from fsck
like the following:

        checking extents
        Check tree block failed, want=833912832, have=0
        Check tree block failed, want=833912832, have=0
        Check tree block failed, want=833912832, have=0
        Check tree block failed, want=833912832, have=0
        Check tree block failed, want=833912832, have=0
        read block failed check_tree_block
        owner ref check failed [833912832 16384]
        Errors found in extent allocation tree or chunk allocation
        checking free space cache
        checking fs roots
        Check tree block failed, want=833912832, have=0
        Check tree block failed, want=833912832, have=0
        Check tree block failed, want=833912832, have=0
        Check tree block failed, want=833912832, have=0
        Check tree block failed, want=833912832, have=0
        read block failed check_tree_block
        root 5 root dir 256 error
        root 5 inode 260 errors 2001, no inode item, link count wrong
                unresolved ref dir 256 index 0 namelen 8 name foobar_3 filetype 1 errors 6, no dir index, no inode ref
        root 5 inode 262 errors 2001, no inode item, link count wrong
                unresolved ref dir 256 index 0 namelen 8 name foobar_5 filetype 1 errors 6, no dir index, no inode ref
        root 5 inode 263 errors 2001, no inode item, link count wrong
        (...)
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NChris Mason <clm@fb.com>

The commit c404e0dc (Btrfs: fix use-after-free in the finishing
procedure of the device replace) fixed a use-after-free problem
which happened when removing the source device at the end of device
replace, but at that time, btrfs didn't support device replace
on raid56, so we didn't fix the problem on the raid56 profile.
Currently, we implemented device replace for raid56, so we need
kick that problem out before we enable that function for raid56.

The fix method is very simple, we just increase the bio per-cpu
counter before we submit a raid56 io, and decrease the counter
when the raid56 io ends.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>

The implementation is simple:
- In order to avoid changing the code logic of btrfs_map_bio and
  RAID56, we add the stripes of the replace target devices at the
  end of the stripe array in btrfs bio, and we sort those target
  device stripes in the array. And we keep the number of the target
  device stripes in the btrfs bio.
- Except write operation on RAID56, all the other operation don't
  take the target device stripes into account.
- When we do write operation, we read the data from the common devices
  and calculate the parity. Then write the dirty data and new parity
  out, at this time, we will find the relative replace target stripes
  and wirte the relative data into it.

Note: The function that copying old data on the source device to
the target device was implemented in the past, it is similar to
the other RAID type.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>

This patch implement the RAID5/6 common data repair function, the
implementation is similar to the scrub on the other RAID such as
RAID1, the differentia is that we don't read the data from the
mirror, we use the data repair function of RAID5/6.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>

stripe_index's value was set again in latter line:
stripe_index = 0;
Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Reviewed-by: NDavid Sterba <dsterba@suse.cz>

bbio_ret in this condition is always !NULL because previous code
already have a check-and-skip:
4908 if (!bbio_ret)
4909     goto out;
Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Reviewed-by: NDavid Sterba <dsterba@suse.cz>

The following lockdep warning is triggered during xfstests:

[ 1702.980872] =========================================================
[ 1702.981181] [ INFO: possible irq lock inversion dependency detected ]
[ 1702.981482] 3.18.0-rc1 #27 Not tainted
[ 1702.981781] ---------------------------------------------------------
[ 1702.982095] kswapd0/77 just changed the state of lock:
[ 1702.982415]  (&delayed_node->mutex){+.+.-.}, at: [<ffffffffa03b0b51>] __btrfs_release_delayed_node+0x41/0x1f0 [btrfs]
[ 1702.982794] but this lock took another, RECLAIM_FS-unsafe lock in the past:
[ 1702.983160]  (&fs_info->dev_replace.lock){+.+.+.}

and interrupts could create inverse lock ordering between them.

[ 1702.984675]
other info that might help us debug this:
[ 1702.985524] Chain exists of:
  &delayed_node->mutex --> &found->groups_sem --> &fs_info->dev_replace.lock

[ 1702.986799]  Possible interrupt unsafe locking scenario:

[ 1702.987681]        CPU0                    CPU1
[ 1702.988137]        ----                    ----
[ 1702.988598]   lock(&fs_info->dev_replace.lock);
[ 1702.989069]                                local_irq_disable();
[ 1702.989534]                                lock(&delayed_node->mutex);
[ 1702.990038]                                lock(&found->groups_sem);
[ 1702.990494]   <Interrupt>
[ 1702.990938]     lock(&delayed_node->mutex);
[ 1702.991407]
 *** DEADLOCK ***

It is because the btrfs_kobj_{add/rm}_device() will call memory
allocation with GFP_KERNEL,
which may flush fs page cache to free space, waiting for it self to do
the commit, causing the deadlock.

To solve the problem, move btrfs_kobj_{add/rm}_device() out of the
dev_replace lock range, also involing split the
btrfs_rm_dev_replace_srcdev() function into remove and free parts.

Now only btrfs_rm_dev_replace_remove_srcdev() is called in dev_replace
lock range, and kobj_{add/rm} and btrfs_rm_dev_replace_free_srcdev() are
called out of the lock range.
Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

bi_sector and bi_size moved to bi_iter since commit 4f024f37
("block: Abstract out bvec iterator")
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NChris Mason <clm@fb.com>

One problem that has plagued us is that a user will use up all of his space with
data, remove a bunch of that data, and then try to create a bunch of small files
and run out of space.  This happens because all the chunks were allocated for
data since the metadata requirements were so low.  But now there's a bunch of
empty data block groups and not enough metadata space to do anything.  This
patch solves this problem by automatically deleting empty block groups.  If we
notice the used count go down to 0 when deleting or on mount notice that a block
group has a used count of 0 then we will queue it to be deleted.

When the cleaner thread runs we will double check to make sure the block group
is still empty and then we will delete it.  This patch has the side effect of no
longer having a bunch of BUG_ON()'s in the chunk delete code, which will be
helpful for both this and relocate.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

This reverts commit b96de000.

This commit is triggering failures to mount by subvolume id in some
configurations.  The main problem is how many different ways this
scanning function is used, both for scanning while mounted and
unmounted.  A proper cleanup is too big for late rcs.

For now, just revert the commit and we'll put a better fix into a later
merge window.
Signed-off-by: NChris Mason <clm@fb.com>

We need real mirror number for RAID0/5/6 when reading data, or if read error
happens, we would pass 0 as the number of the mirror on which the io error
happens. It is wrong and would cause the filesystem read the data from the
corrupted mirror again.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

rw_devices counter is often used to tune the profile when doing chunk allocation,
so we should modify it under the chunk_mutex context to avoid getting wrong
chunk profile.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

For a missing device, we don't know it belong to which fs before we read its
fsid from the chunk tree. So we add them into the current fs device list at first.
When we get its fsid, we should move them to their own fs device list.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

When we open a seed filesystem, if the degraded mount option is set, we continue to
mount the fs if we don't find some devices in the seed filesystem. But we should stop
mounting if other errors happen. Fix it
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

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

The problem is:
	Task0(device scan task)		Task1(device replace task)
	scan_one_device()
	mutex_lock(&uuid_mutex)
	device = find_device()
					mutex_lock(&device_list_mutex)
					lock_chunk()
					rm_and_free_source_device
					unlock_chunk()
					mutex_unlock(&device_list_mutex)
	check device

Destroying the target device if device replace fails also has the same problem.

We fix this problem by locking uuid_mutex during destroying source device or
target device, just like the device remove operation.

It is a temporary solution, we can fix this problem and make the code more
clear by atomic counter in the future.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

We can build a new filesystem based a seed filesystem, and we need clone
the fs devices when we open the new filesystem. But someone might clear
the seed flag of the seed filesystem, then mount that filesystem and
remove some device. If we mount the new filesystem, we might access
a device list which was being changed when we clone the fs devices.
Fix it.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

There were several problems about chunk mutex usage:
- Lock chunk mutex when updating metadata. It would cause the nested
  deadlock because updating metadata might need allocate new chunks
  that need acquire chunk mutex. We remove chunk mutex at this case,
  because b-tree lock and other lock mechanism can help us.
- ABBA deadlock occured between device_list_mutex and chunk_mutex.
  When we update device status, we must acquire device_list_mutex at the
  beginning, and then we might get chunk_mutex during the device status
  update because we need allocate new chunks for metadata COW. But at
  most place, we acquire chunk_mutex at first and then acquire device list
  mutex. We need change the lock order.
- Some place we needn't acquire chunk_mutex. For example we needn't get
  chunk_mutex when we free a empty seed fs_devices structure.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

We didn't protect the system chunk array when we added a new
system chunk into it, it would cause the array be corrupted
if someone remove/add some system chunk into array at the same
time. Fix it by chunk lock.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

->total_bytes,->disk_total_bytes,->bytes_used is protected by chunk
lock when we change them, but sometimes we read them without any lock,
and we might get unexpected value. We fix this problem like inode's
i_size.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

We should update free_chunk_space in time when we allocate a new chunk,
not when we deal with the pending device update and block group insertion,
because we need the real free_chunk_space data to calculate the reserved
space, if we don't update it in time, we would consider the disk space which
has be allocated as free space, and would use it to do overcommit reservation.
Fix it.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

We should update device->bytes_used in the lock context of
chunk_mutex, or we would get wrong data.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

During removing a device, we have modified free_chunk_space when we
shrink the device, so we needn't assign a new value to it after
the device shrink. Fix it.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

device->bytes_used will be changed when allocating a new chunk, and
disk_total_size will be changed if resizing is successful.
Meanwhile, the on-disk super blocks of the previous transaction
might not be updated. Considering the consistency of the metadata
in the previous transaction, We should use the size in the previous
transaction to check if the super block is beyond the boundary
of the device.

Though it is not big problem because we don't use it now, but anyway
it is better that we make it be consistent with the common metadata,
maybe we will use it in the future.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

total_size will be changed when resizing a device, and disk_total_size
will be changed if resizing is successful. Meanwhile, the on-disk super
blocks of the previous transaction might not be updated. Considering
the consistency of the metadata in the previous transaction, We should
use the size in the previous transaction to check if the super block is
beyond the boundary of the device. Fix it.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

We didn't protect the assignment of the target device, it might cause the
problem that the super block update was skipped because we might find wrong
size of the target device during the assignment. Fix it by moving the
assignment sentences into the initialization function of the target device.
And there is another merit that we can check if the target device is suitable
more early.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

The member variants - num_can_discard - of fs_devices structure
are set, but no one use them to do anything. so remove them.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

we are assigning number_devices to the total_bytes,
that's very confusing for a moment
Signed-off-by: NAnand Jain <anand.jain@oracle.com>
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

seed fs devices don't participate as rw_device, so don't increment
rw_devices when the device being handled belongs to a seed fs.
Signed-off-by: NAnand Jain <anand.jain@oracle.com>
Signed-off-by: NChris Mason <clm@fb.com>

When we replace all the seed device in the system there is
no point in just keeping the btrfs_fs_devices with out
any device
Signed-off-by: NAnand Jain <anand.jain@oracle.com>
Signed-off-by: NChris Mason <clm@fb.com>

We are not updating sprout fs seed pointer when all seed device
is replaced. This patch will check if all seed device has been
replaced and then update the sprout pointer accordingly.

Same reproducer as in the previous patch would apply here.
And notice that btrfs_close_device will check if seed fs is
present and spits out the error with out this patch.

int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
{
::
                seed_devices = fs_devices->seed;
::
        while (seed_devices) {
                fs_devices = seed_devices;
                seed_devices = fs_devices->seed;
                __btrfs_close_devices(fs_devices);
                free_fs_devices(fs_devices);
        }
Signed-off-by: NAnand Jain <anand.jain@oracle.com>
Signed-off-by: NChris Mason <clm@fb.com>

reproducer:
mount /dev/sdb /btrfs
btrfs dev add /dev/sdc /btrfs
btrfs rep start -B /dev/sdb /dev/sdd /btrfs
umount /btrfs

WARNING: CPU: 0 PID: 12661 at fs/btrfs/volumes.c:891 __btrfs_close_devices+0x1b0/0x200 [btrfs]()
::

__btrfs_close_devices()
::
        WARN_ON(fs_devices->open_devices);

After the seed device has been replaced the new target device
is no more a seed device. So we need to update the device
numbers in the fs_devices as pointed by the fs_info.
Signed-off-by: NAnand Jain <anand.jain@oracle.com>
Reviewed-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

There is no logical change in this patch, just a preparatory patch,
so that changes can be easily reasoned.
Signed-off-by: NAnand Jain <anand.jain@oracle.com>
Signed-off-by: NChris Mason <clm@fb.com>

None of the uses of btrfs_search_forward() need to have the path
nodes (level >= 1) read locked, only the leaf needs to be locked
while the caller processes it. Therefore make it return a path
with all nodes unlocked, except for the leaf.

This change is motivated by the observation that during a file
fsync we repeatdly call btrfs_search_forward() and process the
returned leaf while upper nodes of the returned path (level >= 1)
are read locked, which unnecessarily blocks other tasks that want
to write to the same fs/subvol btree.
Therefore instead of modifying the fsync code to unlock all nodes
with level >= 1 immediately after calling btrfs_search_forward(),
change btrfs_search_forward() to do it, so that it benefits all
callers.
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NChris Mason <clm@fb.com>

The member variants - latest_devid and latest_trans - of fs_devices structure
are set, but no one use them to do anything. so remove them.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

The io error might happen during writing out the device stats, and the
device stats information and dirty flag would be update at that time,
but the current code didn't consider this case, just clear the dirty
flag, it would cause that we forgot to write out the new device stats
information. Fix it.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>