btrfs: drop useless inode i_flags copy and restore
The patch ("btrfs: start transaction in btrfs_ioctl_setflags()") used
btrfs_set_prop() instead of btrfs_set_prop_trans() by which now the
inode::i_flags update functions such as
btrfs_sync_inode_flags_to_i_flags() and btrfs_update_inode() is called
in btrfs_ioctl_setflags() instead of
btrfs_set_prop_trans()->btrfs_setxattr() as earlier. So the
inode::i_flags remains unmodified until the thread has checked all the
conditions. So drop the saved inode::i_flags in out_i_flags.
Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
btrfs: start transaction in btrfs_ioctl_setflags()
Inode attribute can be set through the FS_IOC_SETFLAGS ioctl. This
flags also includes compression attribute for which we would set/reset
the compression extended attribute. While doing this there is a bit of
duplicate code, the following things happens twice:
- start/end_transaction
- inode_inc_iversion()
- current_time update to inode->i_ctime
- and btrfs_update_inode()
These are updated both at btrfs_ioctl_setflags() and btrfs_set_props()
as well. This patch merges these two duplicate codes at
btrfs_ioctl_setflags().
Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Make btrfs_set_prop() a non-static function, so that it can be called
from btrfs_ioctl_setflags(). We need btrfs_set_prop() instead of
btrfs_set_prop_trans() so that we can use the transaction which is
already started in the current thread.
Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
btrfs: ctree: Dump the leaf before BUG_ON in btrfs_set_item_key_safe
We have a long standing problem with reversed keys that's detected by
btrfs_set_item_key_safe. This is hard to reproduce so we'd like to
capture more information for later analysis.
Let's dump the leaf content before triggering BUG_ON() so that we can
have some clue on what's going wrong. The output of tree locks should
help us to debug such problem.
Filipe Manana [Wed, 17 Apr 2019 10:31:06 +0000 (11:31 +0100)]
Btrfs: improve performance on fsync of files with multiple hardlinks
Commit bd8c0888913d8c ("Btrfs: fix fsync of files with multiple hard links
in new directories") introduced a path that makes fsync fallback to a full
transaction commit in order to avoid losing hard links and new ancestors
of the fsynced inode. That path is triggered only when the inode has more
than one hard link and either has a new hard link created in the current
transaction or the inode was evicted and reloaded in the current
transaction.
That path ends up getting triggered very often (hundreds of times) during
the course of pgbench benchmarks, resulting in performance drops of about
20%.
This change restores the performance by not triggering the full transaction
commit in those cases, and instead iterate the fs/subvolume tree in search
of all possible new ancestors, for all hard links, to log them.
Reported-by: Zhao Yuhu <zyuhu@suse.com> Tested-by: James Wang <jnwang@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Mon, 22 Apr 2019 15:43:42 +0000 (16:43 +0100)]
Btrfs: fix race between send and deduplication that lead to failures and crashes
Send operates on read only trees and expects them to never change while it
is using them. This is part of its initial design, and this expection is
due to two different reasons:
1) When it was introduced, no operations were allowed to modifiy read-only
subvolumes/snapshots (including defrag for example).
2) It keeps send from having an impact on other filesystem operations.
Namely send does not need to keep locks on the trees nor needs to hold on
to transaction handles and delay transaction commits. This ends up being
a consequence of the former reason.
However the deduplication feature was introduced later (on September 2013,
while send was introduced in July 2012) and it allowed for deduplication
with destination files that belong to read-only trees (subvolumes and
snapshots).
That means that having a send operation (either full or incremental) running
in parallel with a deduplication that has the destination inode in one of
the trees used by the send operation, can result in tree nodes and leaves
getting freed and reused while send is using them. This problem is similar
to the problem solved for the root nodes getting freed and reused when a
snapshot is made against one tree that is currenly being used by a send
operation, fixed in commits [1] and [2]. These commits explain in detail
how the problem happens and the explanation is valid for any node or leaf
that is not the root of a tree as well. This problem was also discussed
and explained recently in a thread [3].
The problem is very easy to reproduce when using send with large trees
(snapshots) and just a few concurrent deduplication operations that target
files in the trees used by send. A stress test case is being sent for
fstests that triggers the issue easily. The most common error to hit is
the send ioctl return -EIO with the following messages in dmesg/syslog:
[1631617.204075] BTRFS error (device sdc): did not find backref in send_root. inode=63292, offset=0, disk_byte=5228134400 found extent=5228134400
[1631633.251754] BTRFS error (device sdc): parent transid verify failed on 32243712 wanted 24 found 27
The first one is very easy to hit while the second one happens much less
frequently, except for very large trees (in that test case, snapshots
with 100000 files having large xattrs to get deep and wide trees).
Less frequently, at least one BUG_ON can be hit:
That BUG_ON happens because while send is using a node, that node is COWed
by a concurrent deduplication, gets freed and gets reused as a leaf (because
a transaction commit happened in between), so when it attempts to read a
slot from the extent buffer, at ctree.c:read_node_slot(), the extent buffer
contents were wiped out and it now matches a leaf (which can even belong to
some other tree now), hitting the BUG_ON(level == 0).
Fix this concurrency issue by not allowing send and deduplication to run
in parallel if both operate on the same readonly trees, returning EAGAIN
to user space and logging an exlicit warning in dmesg/syslog.
Filipe Manana [Mon, 15 Apr 2019 08:29:36 +0000 (09:29 +0100)]
Btrfs: send, flush dellaloc in order to avoid data loss
When we set a subvolume to read-only mode we do not flush dellaloc for any
of its inodes (except if the filesystem is mounted with -o flushoncommit),
since it does not affect correctness for any subsequent operations - except
for a future send operation. The send operation will not be able to see the
delalloc data since the respective file extent items, inode item updates,
backreferences, etc, have not hit yet the subvolume and extent trees.
Effectively this means data loss, since the send stream will not contain
any data from existing delalloc. Another problem from this is that if the
writeback starts and finishes while the send operation is in progress, we
have the subvolume tree being being modified concurrently which can result
in send failing unexpectedly with EIO or hitting runtime errors, assertion
failures or hitting BUG_ONs, etc.
$ btrfs receive -f /tmp/send.stream /mnt
$ echo $?
0
$ od -t x1 -A d /mnt/sv/foo 0000000
# ---> empty file
Since this a problem that affects send only, fix it in send by flushing
dellaloc for all the roots used by the send operation before send starts
to process the commit roots.
This is a problem that affects send since it was introduced (commit e6ab399f9f7e91 ("Btrfs: introduce BTRFS_IOC_SEND for btrfs send/receive"))
but backporting it to older kernels has some dependencies:
- For kernels between 3.19 and 4.20, it depends on commit 545ec549825664
("btrfs: use tagged writepage to mitigate livelock of snapshot") because
the function btrfs_start_delalloc_snapshot() does not exist before that
commit. So one has to either pick that commit or replace the calls to
btrfs_start_delalloc_snapshot() in this patch with calls to
btrfs_start_delalloc_inodes().
- For kernels older than 3.19 it also requires commit 948f8f545346b6
("Btrfs: ensure send always works on roots without orphans") because
it depends on the function ensure_commit_roots_uptodate() which that
commits introduced.
- No dependencies for 5.0+ kernels.
A test case for fstests follows soon.
CC: stable@vger.kernel.org # 3.19+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Mon, 15 Apr 2019 13:50:51 +0000 (14:50 +0100)]
Btrfs: do not start a transaction during fiemap
During fiemap, for regular extents (non inline) we need to check if they
are shared and if they are, set the shared bit. Checking if an extent is
shared requires checking the delayed references of the currently running
transaction, since some reference might have not yet hit the extent tree
and be only in the in-memory delayed references.
However we were using a transaction join for this, which creates a new
transaction when there is no transaction currently running. That means
that two more potential failures can happen: creating the transaction and
committing it. Further, if no write activity is currently happening in the
system, and fiemap calls keep being done, we end up creating and
committing transactions that do nothing.
In some extreme cases this can result in the commit of the transaction
created by fiemap to fail with ENOSPC when updating the root item of a
subvolume tree because a join does not reserve any space, leading to a
trace like the following:
Since fiemap (and btrfs_check_shared()) is a read-only operation, do not do
a transaction join to avoid the overhead of creating a new transaction (if
there is currently no running transaction) and introducing a potential
point of failure when the new transaction gets committed, instead use a
transaction attach to grab a handle for the currently running transaction
if any.
Reported-by: Christoph Anton Mitterer <calestyo@scientia.net> Link: https://lore.kernel.org/linux-btrfs/b2a668d7124f1d3e410367f587926f622b3f03a4.camel@scientia.net/ Fixes: cc3006b1e07c0a ("btrfs: fix check_shared for fiemap ioctl") CC: stable@vger.kernel.org # 4.14+ Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Finally, we're at the stage where qgroup + metadata balance cost no
obvious overhead.
Test environment:
Test VM:
- vRAM 8G
- vCPU 8
- block dev vitrio-blk, 'unsafe' cache mode
- host block 850evo
Test workload:
- Copy 4G data from /usr/ to one subvolume
- Create 16 snapshots of that subvolume, and modify 3 files in each
snapshot
- Enable quota, rescan
- Time "btrfs balance start -m"
Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
btrfs: extent-tree: Use btrfs_ref to refactor add_pinned_bytes()
Since add_pinned_bytes() only needs to know if the extent is metadata
and if it's a chunk tree extent, btrfs_ref is a perfect match for it, as
we don't need various owner/level trick to determine extent type.
Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
btrfs: delayed-ref: Use btrfs_ref to refactor btrfs_add_delayed_tree_ref()
btrfs_add_delayed_tree_ref() has a longer and longer parameter list, and
some callers like btrfs_inc_extent_ref() are using @owner as level for
delayed tree ref.
Instead of making the parameter list longer, use btrfs_ref to refactor
it, so each parameter assignment should be self-explaining without dirty
level/owner trick, and provides the basis for later refactoring.
Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
btrfs: extent-tree: Open-code process_func in __btrfs_mod_ref
The process_func function pointer is local to __btrfs_mod_ref() and
points to either btrfs_inc_extent_ref() or btrfs_free_extent().
Open code it to make later delayed ref refactor easier, so we can
refactor btrfs_inc_extent_ref() and btrfs_free_extent() in different
patches.
Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Current delayed ref interface has several problems:
- Longer and longer parameter lists
bytenr
num_bytes
parent
---------- so far so good
ref_root
owner
offset
---------- I don't feel good now
- Different interpretation of the same parameter
Above @owner for data ref is inode number (u64),
while for tree ref, it's level (int).
They are even in different size range.
For level we only need 0 ~ 8, while for ino it's
BTRFS_FIRST_FREE_OBJECTID ~ BTRFS_LAST_FREE_OBJECTID.
And @offset doesn't even make sense for tree ref.
Such parameter reuse may look clever as an hidden union, but it
destroys code readability.
To solve both problems, we introduce a new structure, btrfs_ref to solve
them:
- Structure instead of long parameter list
This makes later expansion easier, and is better documented.
- Use btrfs_ref::type to distinguish data and tree ref
- Use proper union to store data/tree ref specific structures.
- Use separate functions to fill data/tree ref data, with a common generic
function to fill common bytenr/num_bytes members.
All parameters will find its place in btrfs_ref, and an extra member,
@real_root, inspired by ref-verify code, is newly introduced for later
qgroup code, to record which tree is triggered by this extent modification.
This patch doesn't touch any code, but provides the basis for further
refactoring.
Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Wed, 17 Apr 2019 10:30:30 +0000 (11:30 +0100)]
Btrfs: do not start a transaction at iterate_extent_inodes()
When finding out which inodes have references on a particular extent, done
by backref.c:iterate_extent_inodes(), from the BTRFS_IOC_LOGICAL_INO (both
v1 and v2) ioctl and from scrub we use the transaction join API to grab a
reference on the currently running transaction, since in order to give
accurate results we need to inspect the delayed references of the currently
running transaction.
However, if there is currently no running transaction, the join operation
will create a new transaction. This is inefficient as the transaction will
eventually be committed, doing unnecessary IO and introducing a potential
point of failure that will lead to a transaction abort due to -ENOSPC, as
recently reported [1].
That's because the join, creates the transaction but does not reserve any
space, so when attempting to update the root item of the root passed to
btrfs_join_transaction(), during the transaction commit, we can end up
failling with -ENOSPC. Users of a join operation are supposed to actually
do some filesystem changes and reserve space by some means, which is not
the case of iterate_extent_inodes(), it is a read-only operation for all
contextes from which it is called.
The reported [1] -ENOSPC failure stack trace is the following:
Nikolay Borisov [Wed, 10 Apr 2019 16:46:04 +0000 (19:46 +0300)]
btrfs: Remove bio_offset argument from submit_bio_hook
None of the implementers of the submit_bio_hook use the bio_offset
parameter, simply remove it. No functional changes.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Nikolay Borisov [Wed, 10 Apr 2019 14:24:42 +0000 (17:24 +0300)]
btrfs: Always pass 0 bio_offset for btree_submit_bio_start
The btree submit hook queues the async csum and forwards the bio_offset
parameter passed to btree_submit_bio_hook. This is redundant since
btree_submit_bio_start calls btree_csum_one_bio which doesn't use the
offset at all. No functional changes.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Nikolay Borisov [Wed, 10 Apr 2019 14:24:41 +0000 (17:24 +0300)]
btrfs: Pass 0 for bio_offset to btrfs_wq_submit_bio
Buffered writeback always calls btrfs_csum_one_bio with the last 2
arguments being 0 irrespective of what the bio_offset has been passed to
btrfs_submit_bio_start. Make this apparent by explicitly passing 0 for
bio_offset when calling btrfs_wq_submit_bio from btrfs_submit_bio_hook.
This will allow for further simplifications down the line. No functional
changes.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Nikolay Borisov [Wed, 10 Apr 2019 14:24:40 +0000 (17:24 +0300)]
btrfs: Remove 'tree' argument from read_extent_buffer_pages
This function always uses the btree inode's io_tree. Stop taking the
tree as a function argument and instead access it internally from
read_extent_buffer_pages. No functional changes.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Nikolay Borisov [Wed, 10 Apr 2019 14:24:39 +0000 (17:24 +0300)]
btrfs: Change submit_bio_hook to taking an inode directly
The only possible 'private_data' that is passed to this function is
actually an inode. Make that explicit by changing the signature of the
call back. No functional changes.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Nikolay Borisov [Wed, 10 Apr 2019 14:24:38 +0000 (17:24 +0300)]
btrfs: Define submit_bio_hook's type directly
There is no need to use a typedef to define the type of the function and
then use that to define the respective member in extent_io_ops. Define
struct's member directly. No functional changes.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
David Sterba [Wed, 20 Mar 2019 13:11:21 +0000 (14:11 +0100)]
btrfs: get fs_info from block group in search_free_space_info
We can read fs_info from the block group cache structure and can drop it
from the parameters. Though the transaction is also availabe, it's not
guaranteed to be non-NULL.
Filipe Manana [Wed, 17 Apr 2019 09:28:47 +0000 (10:28 +0100)]
Btrfs: remove no longer used function to run delayed refs asynchronously
It used to be called from only two places (truncate path and releasing a
transaction handle), but commits e433e9efb7b28c ("btrfs: fix truncate
throttling") and d1da3c12e671f2 ("btrfs: don't run delayed refs in the end
transaction logic") removed their calls to this function, so it's not used
anymore. Just remove it and all its helpers.
Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
btrfs: remove redundant readonly root check in btrfs_setxattr_trans
btrfs_setxattr_trans() is called by 5 functions as below and all of them
do updates. None of them would be roun on a read-only root.
So its ok to remove the readonly root check here as it's a high-level
conditon.
Preparatory patch, as we are going split the calls with and without
transaction to use the respective btrfs_setxattr() and
btrfs_setxattr_trans() functions. Export btrfs_setxattr() for calls
outside of xattr.c.
Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
When trans is not NULL btrfs_setxattr() calls do_setxattr() directly
with a check for readonly root. Rename do_setxattr() btrfs_setxattr() in
preparation to call do_setxattr() directly instead. Preparatory patch,
no functional changes.
Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
btrfs: trace: Introduce trace events for all btrfs tree locking events
Unlike btrfs_tree_lock() and btrfs_tree_read_lock(), the remaining
functions in locking.c will not sleep, thus doesn't make much sense to
record their execution time.
Those events are introduced mainly for user space tool to audit and
detect lock leakage or dead lock.
Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
btrfs: trace: Introduce trace events for sleepable tree lock
There are two tree lock events which can sleep:
- btrfs_tree_read_lock()
- btrfs_tree_lock()
Sometimes we may need to look into the concurrency picture of the fs.
For that case, we need the execution time of above two functions and the
owner of @eb.
Here we introduce a trace events for user space tools like bcc, to get
the execution time of above two functions, and get detailed owner info
where eBPF code can't.
All the overhead is hidden behind the trace events, so if events are not
enabled, there is no overhead.
These trace events also output bytenr and generation, allow them to be
pared with unlock events to pin down deadlock.
Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Mon, 15 Apr 2019 08:29:19 +0000 (09:29 +0100)]
Btrfs: remove no longer used member num_dirty_bgs from transaction
The member num_dirty_bgs of struct btrfs_transaction is not used anymore,
it is set and incremented but nothing reads its value anymore. Its last
read use was removed by commit 3ed1d076386de7 ("btrfs: rework
btrfs_check_space_for_delayed_refs"). So just remove that member.
Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Nikolay Borisov [Wed, 10 Apr 2019 13:16:11 +0000 (16:16 +0300)]
btrfs: Remove redundant inode argument from btrfs_add_ordered_sum
Ordered csums are keyed off of a btrfs_ordered_extent, which already has
a reference to the inode. This implies that an explicit inode argument
is redundant. So remove it.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
btrfs: Do mandatory tree block check before submitting bio
There are at least 2 reports about a memory bit flip sneaking into
on-disk data.
Currently we only have a relaxed check triggered at
btrfs_mark_buffer_dirty() time, as it's not mandatory and only for
CONFIG_BTRFS_FS_CHECK_INTEGRITY enabled build, it doesn't help users to
detect such problem.
This patch will address the hole by triggering comprehensive check on
tree blocks before writing it back to disk.
The design points are:
- Timing of the check: Tree block write hook
This timing is chosen to reduce the overhead.
The comprehensive check should be as expensive as a checksum
calculation.
Doing full check at btrfs_mark_buffer_dirty() is too expensive for end
user.
- Loose empty leaf check
Originally for an empty leaf, tree-checker will report error if it's
not a tree root.
The problem for such check at write time is:
* False alert for tree root created in current transaction
In that case, the commit root still needs to be written to disk.
And since current root can differ from commit root, then it will
cause false alert.
This happens for log tree.
* False alert for relocated tree block
Relocated tree block can be written to disk due to memory pressure,
in that case an empty csum tree root can be written to disk and
cause false alert, since csum root node hasn't been updated.
Previous patch of removing comprehensive empty leaf owner check has
paved the way for this patch.
The example error output will be something like:
BTRFS critical (device dm-3): corrupt leaf: root=2 block=1350630375424 slot=68, bad key order, prev (10510212874240 169 0) current (1714119868416 169 0)
BTRFS error (device dm-3): block=1350630375424 write time tree block corruption detected
BTRFS: error (device dm-3) in btrfs_commit_transaction:2220: errno=-5 IO failure (Error while writing out transaction)
BTRFS info (device dm-3): forced readonly
BTRFS warning (device dm-3): Skipping commit of aborted transaction.
BTRFS: error (device dm-3) in cleanup_transaction:1839: errno=-5 IO failure
BTRFS info (device dm-3): delayed_refs has NO entry
Reported-by: Leonard Lausen <leonard@lausen.nl> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Robbie Ko [Tue, 26 Mar 2019 03:56:11 +0000 (11:56 +0800)]
Btrfs: fix data bytes_may_use underflow with fallocate due to failed quota reserve
When doing fallocate, we first add the range to the reserve_list and
then reserve the quota. If quota reservation fails, we'll release all
reserved parts of reserve_list.
However, cur_offset is not updated to indicate that this range is
already been inserted into the list. Therefore, the same range is freed
twice. Once at list_for_each_entry loop, and once at the end of the
function. This will result in WARN_ON on bytes_may_use when we free the
remaining space.
At the end, under the 'out' label we have a call to:
Nikolay Borisov [Wed, 27 Mar 2019 12:24:18 +0000 (14:24 +0200)]
btrfs: Switch btrfs_trim_free_extents to find_first_clear_extent_bit
Instead of always calling the allocator to search for a free extent,
that satisfies the input criteria, switch btrfs_trim_free_extents to
using find_first_clear_extent_bit. With this change it's no longer
necessary to read the device tree in order to figure out holes in
the devices.
Now the code always searches in-memory data structure to figure out the
space range which contains the requested which should result in speed
improvements.
Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Nikolay Borisov [Wed, 27 Mar 2019 12:24:17 +0000 (14:24 +0200)]
btrfs: Implement find_first_clear_extent_bit
This function is very similar to find_first_extent_bit except that it
locates the first contiguous span of space which does not have bits set.
It's intended use is in the freespace trimming code.
Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Nikolay Borisov [Wed, 27 Mar 2019 12:24:16 +0000 (14:24 +0200)]
btrfs: Optimize unallocated chunks discard
Currently unallocated chunks are always trimmed. For example
2 consecutive trims on large storage would trim freespace twice
irrespective of whether the space was actually allocated or not between
those trims.
Optimise this behavior by exploiting the newly introduced alloc_state
tree of btrfs_device. A new CHUNK_TRIMMED bit is used to mark
those unallocated chunks which have been trimmed and have not been
allocated afterwards. On chunk allocation the respective underlying devices'
physical space will have its CHUNK_TRIMMED flag cleared. This avoids
submitting discards for space which hasn't been changed since the last
time discard was issued.
This applies to the single mount period of the filesystem as the
information is not stored permanently.
Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Nikolay Borisov [Wed, 27 Mar 2019 12:24:14 +0000 (14:24 +0200)]
btrfs: Remove 'trans' argument from find_free_dev_extent(_start)
Now that these functions no longer require a handle to transaction to
inspect pending/pinned chunks the argument can be removed. At the same
time also remove any surrounding code which acquired the handle.
Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Jeff Mahoney [Wed, 27 Mar 2019 12:24:12 +0000 (14:24 +0200)]
btrfs: replace pending/pinned chunks lists with io tree
The pending chunks list contains chunks that are allocated in the
current transaction but haven't been created yet. The pinned chunks
list contains chunks that are being released in the current transaction.
Both describe chunks that are not reflected on disk as in use but are
unavailable just the same.
The pending chunks list is anchored by the transaction handle, which
means that we need to hold a reference to a transaction when working
with the list.
The way we use them is by iterating over both lists to perform
comparisons on the stripes they describe for each device. This is
backwards and requires that we keep a transaction handle open while
we're trimming.
This patchset adds an extent_io_tree to btrfs_device that maintains
the allocation state of the device. Extents are set dirty when
chunks are first allocated -- when the extent maps are added to the
mapping tree. They're cleared when last removed -- when the extent
maps are removed from the mapping tree. This matches the lifespan
of the pending and pinned chunks list and allows us to do trims
on unallocated space safely without pinning the transaction for what
may be a lengthy operation. We can also use this io tree to mark
which chunks have already been trimmed so we don't repeat the operation.
Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Nikolay Borisov [Tue, 12 Feb 2019 14:13:14 +0000 (16:13 +0200)]
btrfs: Transpose btrfs_close_devices/btrfs_mapping_tree_free in close_ctree
Following the introduction of the alloc_state tree, some of the callees
of btrfs_mapping_tree_free will have to interact with the btrfs_device
of the constituent devices. Enable this by moving the code responsible
for freeing devices after the last user (btrfs_mapping_tree_free).
Otherwise the kernel could crash due to use-after-free.
Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Nikolay Borisov [Wed, 27 Mar 2019 12:24:11 +0000 (14:24 +0200)]
btrfs: Stop using call_rcu for device freeing
btrfs_device structs are freed from RCU context since device iteration
is protected by RCU. Currently this is achieved by using call_rcu since
no blocking functions are called within btrfs_free_device. Future
refactoring of pending/pinned chunks will require calling sleeping
functions.
This patch is in preparation for these changes by simply switching from
RCU callbacks to explicit calls of synchronize_rcu and calling
btrfs_free_device directly. This is functionally equivalent, making sure
that there are no readers at that time.
Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Nikolay Borisov [Mon, 25 Mar 2019 12:31:26 +0000 (14:31 +0200)]
btrfs: Introduce new bits for device allocation tree
Rather than hijacking the existing defines let's just define new bits,
with more descriptive names. Instead of using yet more (currently at 18)
bits for the new flags, use the fact those flags will be specific to
the device allocation tree so define them using existing EXTENT_* flags.
Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Nikolay Borisov [Mon, 25 Mar 2019 12:31:25 +0000 (14:31 +0200)]
btrfs: Populate ->orig_block_len during read_one_chunk
Chunks read from disk currently don't get their ->orig_block_len member
set, in contrast when a new chunk is allocated, the respective
extent_map's ->orig_block_len is assigned the size of the stripe of this
chunk.
Let's apply the same strategy for chunks which are read from
disk, not only does this codify the invariant that ->orig_block_len
always contains the size of the stripe for a chunk (when the em belongs
to the mapping tree). But it's also a preparatory patch for further work
around tracking chunk allocation in an extent tree rather than
pinned/pending lists.
Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Nikolay Borisov [Mon, 25 Mar 2019 12:31:24 +0000 (14:31 +0200)]
btrfs: Rename and export clear_btree_io_tree
This function is going to be used to clear out the device extent
allocation information. Give it a more generic name and export it. This
is in preparation to replacing the pending/pinned chunk lists with an
extent tree. 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>
projects / kernel.git / log