[BUG]
btrfs incremental send BUG happens when creating a snapshot of snapshot
that is being used by send.
[REASON]
The problem can happen if while we are doing a send one of the snapshots
used (parent or send) is snapshotted, because snapshoting implies COWing
the root of the source subvolume/snapshot.
1. When doing an incremental send, the send process will get the commit
roots from the parent and send snapshots, and add references to them
through extent_buffer_get().
2. When a snapshot/subvolume is snapshotted, its root node is COWed
(transaction.c:create_pending_snapshot()).
3. COWing releases the space used by the node immediately, through:
__btrfs_cow_block()
--btrfs_free_tree_block()
----btrfs_add_free_space(bytenr of node)
4. Because send doesn't hold a transaction open, it's possible that
the transaction used to create the snapshot commits, switches the
commit root and the old space used by the previous root node gets
assigned to some other node allocation. Allocation of a new node will
use the existing extent buffer found in memory, which we previously
got a reference through extent_buffer_get(), and allow the extent
buffer's content (pages) to be modified:
btrfs_alloc_tree_block
--btrfs_reserve_extent
----find_free_extent (get bytenr of old node)
--btrfs_init_new_buffer (use bytenr of old node)
----btrfs_find_create_tree_block
------alloc_extent_buffer
--------find_extent_buffer (get old node)
5. So send can access invalid memory content and have unpredictable
behaviour.
[FIX]
So we fix the problem by copying the commit roots of the send and
parent snapshots and use those copies.
CallTrace looks like this:
------------[ cut here ]------------
kernel BUG at fs/btrfs/ctree.c:1861!
invalid opcode: 0000 [#1] SMP
CPU: 6 PID: 24235 Comm: btrfs Tainted: P O 3.10.105 #23721
ffff88046652d680 ti: ffff88041b720000 task.ti: ffff88041b720000
RIP: 0010:[<ffffffffa08dd0e8>] read_node_slot+0x108/0x110 [btrfs]
RSP: 0018:ffff88041b723b68 EFLAGS: 00010246
RAX: ffff88043ca6b000 RBX: ffff88041b723c50 RCX: ffff880000000000
RDX: 000000000000004c RSI: ffff880314b133f8 RDI: ffff880458b24000
RBP: 0000000000000000 R08: 0000000000000001 R09: ffff88041b723c66
R10: 0000000000000001 R11: 0000000000001000 R12: ffff8803f3e48890
R13: ffff8803f3e48880 R14: ffff880466351800 R15: 0000000000000001
FS: 00007f8c321dc8c0(0000) GS:ffff88047fcc0000(0000)
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
R2: 00007efd1006d000 CR3: 0000000213a24000 CR4: 00000000003407e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
ffff88041b723c50 ffff8803f3e48880 ffff8803f3e48890 ffff8803f3e48880
ffff880466351800 0000000000000001 ffffffffa08dd9d7 ffff88041b723c50
ffff8803f3e48880 ffff88041b723c66 ffffffffa08dde85 a9ff88042d2c4400
Call Trace:
[<ffffffffa08dd9d7>] ? tree_move_down.isra.33+0x27/0x50 [btrfs]
[<ffffffffa08dde85>] ? tree_advance+0xb5/0xc0 [btrfs]
[<ffffffffa08e83d4>] ? btrfs_compare_trees+0x2d4/0x760 [btrfs]
[<ffffffffa0982050>] ? finish_inode_if_needed+0x870/0x870 [btrfs]
[<ffffffffa09841ea>] ? btrfs_ioctl_send+0xeda/0x1050 [btrfs]
[<ffffffffa094bd3d>] ? btrfs_ioctl+0x1e3d/0x33f0 [btrfs]
[<ffffffff81111133>] ? handle_pte_fault+0x373/0x990
[<ffffffff8153a096>] ? atomic_notifier_call_chain+0x16/0x20
[<ffffffff81063256>] ? set_task_cpu+0xb6/0x1d0
[<ffffffff811122c3>] ? handle_mm_fault+0x143/0x2a0
[<ffffffff81539cc0>] ? __do_page_fault+0x1d0/0x500
[<ffffffff81062f07>] ? check_preempt_curr+0x57/0x90
[<ffffffff8115075a>] ? do_vfs_ioctl+0x4aa/0x990
[<ffffffff81034f83>] ? do_fork+0x113/0x3b0
[<ffffffff812dd7d7>] ? trace_hardirqs_off_thunk+0x3a/0x6c
[<ffffffff81150cc8>] ? SyS_ioctl+0x88/0xa0
[<ffffffff8153e422>] ? system_call_fastpath+0x16/0x1b
---[ end trace 29576629ee80b2e1 ]---
Fixes: 7069830a9e ("Btrfs: add btrfs_compare_trees function")
CC: stable@vger.kernel.org # 3.6+
Signed-off-by: Robbie Ko <robbieko@synology.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Remove GPL boilerplate text (long, short, one-line) and keep the rest,
ie. personal, company or original source copyright statements. Add the
SPDX header.
Signed-off-by: David Sterba <dsterba@suse.com>
Once there was a simple int force_cow that was used with the plain
barriers, and then converted to a bit, so we should use the appropriate
barrier helper.
Other variables in the complex if condition do not depend on a barrier,
so we should be fine in case the atomic barrier becomes a no-op.
Signed-off-by: David Sterba <dsterba@suse.com>
We have several reports about node pointer points to incorrect child
tree blocks, which could have even wrong owner and level but still with
valid generation and checksum.
Although btrfs check could handle it and print error message like:
leaf parent key incorrect 60670574592
Kernel doesn't have enough check on this type of corruption correctly.
At least add such check to read_tree_block() and btrfs_read_buffer(),
where we need two new parameters @level and @first_key to verify the
child tree block.
The new @level check is mandatory and all call sites are already
modified to extract expected level from its call chain.
While @first_key is optional, the following call sites are skipping such
check:
1) Root node/leaf
As ROOT_ITEM doesn't contain the first key, skip @first_key check.
2) Direct backref
Only parent bytenr and level is known and we need to resolve the key
all by ourselves, skip @first_key check.
Another note of this verification is, it needs extra info from nodeptr
or ROOT_ITEM, so it can't fit into current tree-checker framework, which
is limited to node/leaf boundary.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A useless wrapper around tree_mod_log_insert_root that hides missing
error handling. Move it to the callers.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A trivial wrapper that can be simply opencoded and makes the GFP
allocation request more visible. The error handling is now moved to the
callers.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The wrapper is effectively an alias for tree_mod_log_insert_move but
also hides the missing error handling. To make that more visible, lift
the BUG_ON to the callers.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The wrappers are trivial and do not bring any extra value on top of the
plain locking primitives.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This function always sets keep_locks to 1 and saves the old value of
keep_locks which is restored at the end. So there is no way it can be
called without keep_locks being set. Remove comment imposing redundant
requirement on callers.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently there are 2 function doing binary search on btrfs nodes:
bin_search and btrfs_bin_search. The latter being a simple wrapper for
the former. So eliminate the wrapper and just rename bin_search to
btrfs_bin_search. No functional changes
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When modifying a tree where the root is at BTRFS_MAX_LEVEL - 1 then
the level variable is going to be 7 (this is the max height of the
tree). On the other hand btrfs_cow_block is always called with
"level + 1" as an index into the nodes and slots arrays. This leads to
an out of bounds access. Admittdely this will be benign since an OOB
access of the nodes array will likely read the 0th element from the
slots array, which in this case is going to be 0 (since we start CoW at
the top of the tree). The OOB access into the slots array in turn will
read the 0th and 1st values of the locks array, which would both be 0
at the time. However, this benign behavior relies on the fact that the
path being passed hasn't been initialised, if it has already been used to
query a btree then it could potentially have populated the nodes/slots arrays.
Fix it by explicitly checking if we are at level 7 (the maximum allowed
index in nodes/slots arrays) and explicitly call the CoW routine with
NULL for parent's node/slot.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Fixes-coverity-id: 711515
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since commit fb235dc06f (btrfs: qgroup: Move half of the qgroup
accounting time out of commit trans) the assumption that
btrfs_add_delayed_{data,tree}_ref can only return 0 or -ENOMEM has
been false. The qgroup operations call into btrfs_search_slot
and friends and can now return the full spectrum of error codes.
Fortunately, the fix here is easy since update_ref_for_cow failing
is already handled so we just need to bail early with the error
code.
Fixes: fb235dc06f (btrfs: qgroup: Move half of the qgroup accounting ...)
Cc: <stable@vger.kernel.org> # v4.11+
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Edmund Nadolski <enadolski@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We need the actual root for the ref verifier tool to work, so change
these functions to pass the root around instead. This will be used in
a subsequent patch.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_changed_cb_t represents the signature of the callback being passed
to btrfs_compare_trees. Currently there is only one such callback,
namely changed_cb in send.c. This function doesn't really uses the first
2 parameters, i.e. the roots. Since there are not other functions
implementing the btrfs_changed_cb_t let's remove the unused parameters
from the prototype and implementation.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
As we don't use vmalloc/vzalloc/vfree directly in ctree.c, we can now
use the proper header that defines kvmalloc.
Signed-off-by: David Sterba <dsterba@suse.com>
Commit 5f39d397df ("Btrfs: Create extent_buffer interface
for large blocksizes") refactored btrfs_leaf_data function to take
extent_buffer rather than struct btrfs_leaf. However, as it turns out the
parameter being passed is never used. Furthermore this function no longer
returns the leaf data but rather the offset to it. So rename the function
to BTRFS_LEAF_DATA_OFFSET to make it consistent with other BTRFS_LEAF_*
helpers and turn it into a macro.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
[ removed () from the macro ]
Signed-off-by: David Sterba <dsterba@suse.com>
Pull btrfs updates from Chris Mason:
"This has fixes and cleanups Dave Sterba collected for the merge
window.
The biggest functional fixes are between btrfs raid5/6 and scrub, and
raid5/6 and device replacement. Some of our pending qgroup fixes are
included as well while I bash on the rest in testing.
We also have the usual set of cleanups, including one that makes
__btrfs_map_block() much more maintainable, and conversions from
atomic_t to refcount_t"
* 'for-linus-4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (71 commits)
btrfs: fix the gfp_mask for the reada_zones radix tree
Btrfs: fix reported number of inode blocks
Btrfs: send, fix file hole not being preserved due to inline extent
Btrfs: fix extent map leak during fallocate error path
Btrfs: fix incorrect space accounting after failure to insert inline extent
Btrfs: fix invalid attempt to free reserved space on failure to cow range
btrfs: Handle delalloc error correctly to avoid ordered extent hang
btrfs: Fix metadata underflow caused by btrfs_reloc_clone_csum error
btrfs: check if the device is flush capable
btrfs: delete unused member nobarriers
btrfs: scrub: Fix RAID56 recovery race condition
btrfs: scrub: Introduce full stripe lock for RAID56
btrfs: Use ktime_get_real_ts for root ctime
Btrfs: handle only applicable errors returned by btrfs_get_extent
btrfs: qgroup: Fix qgroup corruption caused by inode_cache mount option
btrfs: use q which is already obtained from bdev_get_queue
Btrfs: switch to div64_u64 if with a u64 divisor
Btrfs: update scrub_parity to use u64 stripe_len
Btrfs: enable repair during read for raid56 profile
btrfs: use clear_page where appropriate
...
There are many code paths opencoding kvmalloc. Let's use the helper
instead. The main difference to kvmalloc is that those users are
usually not considering all the aspects of the memory allocator. E.g.
allocation requests <= 32kB (with 4kB pages) are basically never failing
and invoke OOM killer to satisfy the allocation. This sounds too
disruptive for something that has a reasonable fallback - the vmalloc.
On the other hand those requests might fallback to vmalloc even when the
memory allocator would succeed after several more reclaim/compaction
attempts previously. There is no guarantee something like that happens
though.
This patch converts many of those places to kv[mz]alloc* helpers because
they are more conservative.
Link: http://lkml.kernel.org/r/20170306103327.2766-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> # Xen bits
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Andreas Dilger <andreas.dilger@intel.com> # Lustre
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> # KVM/s390
Acked-by: Dan Williams <dan.j.williams@intel.com> # nvdim
Acked-by: David Sterba <dsterba@suse.com> # btrfs
Acked-by: Ilya Dryomov <idryomov@gmail.com> # Ceph
Acked-by: Tariq Toukan <tariqt@mellanox.com> # mlx4
Acked-by: Leon Romanovsky <leonro@mellanox.com> # mlx5
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Santosh Raspatur <santosh@chelsio.com>
Cc: Hariprasad S <hariprasad@chelsio.com>
Cc: Yishai Hadas <yishaih@mellanox.com>
Cc: Oleg Drokin <oleg.drokin@intel.com>
Cc: "Yan, Zheng" <zyan@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
All callers dereference the 'tm' parameter before it gets to this
function, the NULL check does not make much sense here.
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Before attempting to split a leaf we try to migrate items from the leaf to
its right and left siblings. We start by trying to move items into the
rigth sibling and, if the new item is meant to be inserted at the end of
our leaf, we try to free from our leaf an amount of bytes equal to the
number of bytes used by the new item, by setting the variable space_needed
to the byte size of that new item. However if we fail to move enough items
to the right sibling due to lack of space in that sibling, we then try
to move items into the left sibling, and in that case we try to free
an amount equal to the size of the new item from our leaf, when we need
only to free an amount corresponding to the size of the new item minus
the current free space of our leaf. So make sure that before we try to
move items to the left sibling we do set the variable space_needed with
a value corresponding to the new item's size minus the leaf's current
free space.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
@trans is not used at all, this removes it.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In a lot of places, it's unclear when it's safe to reuse a struct
btrfs_key after it has been passed to a helper function. Constify these
arguments wherever possible to make it obvious.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
To make the code clearer, use rb_entry() instead of container_of() to
deal with rbtree.
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are loads of functions in btrfs that accept a root parameter
but only use it to obtain an fs_info pointer. Let's convert those to
just accept an fs_info pointer directly.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In routines where someptr->fs_info is referenced multiple times, we
introduce a convenience variable. This makes the code considerably
more readable.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We track the node sizes per-root, but they never vary from the values
in the superblock. This patch messes with the 80-column style a bit,
but subsequent patches to factor out root->fs_info into a convenience
variable fix it up again.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Using copy_extent_buffer is suitable for copying betwenn buffers from an
arbitrary offset and deals with page boundaries. This is not necessary
when doing a full extent_buffer-to-extent_buffer copy. We can utilize
the copy_page helper as well.
Signed-off-by: David Sterba <dsterba@suse.com>
The only memset we do is to 0, so sink the parameter to the function and
simplify all calls. Rename the function to reflect the behaviour.
Signed-off-by: David Sterba <dsterba@suse.com>
During the time, the function has been shrunk to the point that it just
calls find_extent_buffer, just passing the parameters.
Signed-off-by: David Sterba <dsterba@suse.com>
