Instead of doing it in two steps outside of delayed-ref.c, leaking low
level details such as locking, move the logic entirely to delayed-ref.c
under btrfs_select_ref_head(), reducing code and making things simpler
for the caller.
Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The function only returns 0, meaning it was able to lock the delayed ref
head, or -EAGAIN in case it wasn't able to lock it. So simplify this and
use a boolean return type instead, returning true if it was able to lock
and false otherwise.
Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The atomic counter 'num_entries' is not used anymore, we increment it
and decrement it but then we don't ever read it to use for any logic.
Its last use was removed with commit 61a56a992f ("btrfs: delayed refs
pre-flushing should only run the heads we have"). So remove it.
Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When inserting extent backref, in order to check whether refs other than
inline refs are used, we always use path keep locks for tree search, which
will increase the lock contention of extent tree.
We do not need the parent node every time to determine whether normal
refs are used. It is only needed when the extent item is the last item
in a leaf.
Therefore, we change it to first use keep_locks=0 for search. If the
extent item happens to be the last item in the leaf, we then change to
keep_locks=1 for the second search to reduce lock contention.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Robbie Ko <robbieko@synology.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The parameter duplicates what can be effectively obtained from
wc->refs[level - 1] and this is what's actually used inside. Added in
commit 2b73c7e761 ("btrfs: unify logic to decide if we need to walk
down into a node during snapshot delete").
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are reports that system cannot suspend due to running trim because
the task responsible for trimming the device isn't able to finish in
time, especially since we have a free extent discarding phase, which can
trim a lot of unallocated space. There are no limits on the trim size
(unlike the block group part).
Since trime isn't a critical call it can be interrupted at any time,
in such cases we stop the trim, report the amount of discarded bytes and
return an error.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=219180
Link: https://bugzilla.suse.com/show_bug.cgi?id=1229737
CC: stable@vger.kernel.org # 5.15+
Signed-off-by: Luca Stefani <luca.stefani.ge1@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Per Qu Wenruo in case we have a very large disk, e.g. 8TiB device,
mostly empty although we will do the split according to our super block
locations, the last super block ends at 256G, we can submit a huge
discard for the range [256G, 8T), causing a large delay.
Split the space left to discard based on BTRFS_MAX_DISCARD_CHUNK_SIZE in
preparation of introduction of cancellation points to trim. The value
of the chunk size is arbitrary, it can be higher or derived from actual
device capabilities but we can't easily read that using
bio_discard_limit().
Link: https://bugzilla.kernel.org/show_bug.cgi?id=219180
Link: https://bugzilla.suse.com/show_bug.cgi?id=1229737
CC: stable@vger.kernel.org # 5.15+
Signed-off-by: Luca Stefani <luca.stefani.ge1@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Even in case of failure we could've discarded some data and userspace
should be made aware of it, so copy fstrim_range to userspace
regardless.
Also make sure to update the trimmed bytes amount even if
btrfs_trim_free_extents fails.
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Luca Stefani <luca.stefani.ge1@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In the patch 78c52d9eb6 ("btrfs: check for refs on snapshot delete
resume") I added some code to handle file systems that had been
corrupted by a bug that incorrectly skipped updating the drop progress
key while dropping a snapshot. This code would check to see if we had
already deleted our reference for a child block, and skip the deletion
if we had already.
Unfortunately there is a bug, as the check would only check the on-disk
references. I made an incorrect assumption that blocks in an already
deleted snapshot that was having the deletion resume on mount wouldn't
be modified.
If we have 2 pending deleted snapshots that share blocks, we can easily
modify the rules for a block. Take the following example
subvolume a exists, and subvolume b is a snapshot of subvolume a. They
share references to block 1. Block 1 will have 2 full references, one
for subvolume a and one for subvolume b, and it belongs to subvolume a
(btrfs_header_owner(block 1) == subvolume a).
When deleting subvolume a, we will drop our full reference for block 1,
and because we are the owner we will drop our full reference for all of
block 1's children, convert block 1 to FULL BACKREF, and add a shared
reference to all of block 1's children.
Then we will start the snapshot deletion of subvolume b. We look up the
extent info for block 1, which checks delayed refs and tells us that
FULL BACKREF is set, so sets parent to the bytenr of block 1. However
because this is a resumed snapshot deletion, we call into
check_ref_exists(). Because check_ref_exists() only looks at the disk,
it doesn't find the shared backref for the child of block 1, and thus
returns 0 and we skip deleting the reference for the child of block 1
and continue. This orphans the child of block 1.
The fix is to lookup the delayed refs, similar to what we do in
btrfs_lookup_extent_info(). However we only care about whether the
reference exists or not. If we fail to find our reference on disk, go
look up the bytenr in the delayed refs, and if it exists look for an
existing ref in the delayed ref head. If that exists then we know we
can delete the reference safely and carry on. If it doesn't exist we
know we have to skip over this block.
This bug has existed since I introduced this fix, however requires
having multiple deleted snapshots pending when we unmount. We noticed
this in production because our shutdown path stops the container on the
system, which deletes a bunch of subvolumes, and then reboots the box.
This gives us plenty of opportunities to hit this issue. Looking at the
history we've seen this occasionally in production, but we had a big
spike recently thanks to faster machines getting jobs with multiple
subvolumes in the job.
Chris Mason wrote a reproducer which does the following
mount /dev/nvme4n1 /btrfs
btrfs subvol create /btrfs/s1
simoop -E -f 4k -n 200000 -z /btrfs/s1
while(true) ; do
btrfs subvol snap /btrfs/s1 /btrfs/s2
simoop -f 4k -n 200000 -r 10 -z /btrfs/s2
btrfs subvol snap /btrfs/s2 /btrfs/s3
btrfs balance start -dusage=80 /btrfs
btrfs subvol del /btrfs/s2 /btrfs/s3
umount /btrfs
btrfsck /dev/nvme4n1 || exit 1
mount /dev/nvme4n1 /btrfs
done
On the second loop this would fail consistently, with my patch it has
been running for hours and hasn't failed.
I also used dm-log-writes to capture the state of the failure so I could
debug the problem. Using the existing failure case to test my patch
validated that it fixes the problem.
Fixes: 78c52d9eb6 ("btrfs: check for refs on snapshot delete resume")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When btrfs makes a block group read-only, it adds all free regions in the
block group to space_info->bytes_readonly. That free space excludes
reserved and pinned regions. OTOH, when btrfs makes the block group
read-write again, it moves all the unused regions into the block group's
zone_unusable. That unused region includes reserved and pinned regions.
As a result, it counts too much zone_unusable bytes.
Fortunately (or unfortunately), having erroneous zone_unusable does not
affect the calculation of space_info->bytes_readonly, because free
space (num_bytes in btrfs_dec_block_group_ro) calculation is done based on
the erroneous zone_unusable and it reduces the num_bytes just to cancel the
error.
This behavior can be easily discovered by adding a WARN_ON to check e.g,
"bg->pinned > 0" in btrfs_dec_block_group_ro(), and running fstests test
case like btrfs/282.
Fix it by properly considering pinned and reserved in
btrfs_dec_block_group_ro(). Also, add a WARN_ON and introduce
btrfs_space_info_update_bytes_zone_unusable() to catch a similar mistake.
Fixes: 169e0da91a ("btrfs: zoned: track unusable bytes for zones")
CC: stable@vger.kernel.org # 5.15+
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We always allocate a delayed extent op structure when allocating a tree
block (except for log trees), but most of the time we don't need it as
we only need to set the BTRFS_BLOCK_FLAG_FULL_BACKREF if we're dealing
with a relocation tree and we only need to set the key of a tree block
in a btrfs_tree_block_info structure if we are not using skinny metadata
(feature enabled by default since btrfs-progs 3.18 and available as of
kernel 3.10).
In these cases, where we don't need neither to update flags nor to set
the key, we only use the delayed extent op structure to set the tree
block's level. This is a waste of memory and besides that, the memory
allocation can fail and can add additional latency.
Instead of using a delayed extent op structure to store the level of
the tree block, use the delayed ref head to store it. This doesn't
change the size of neither structure and helps us avoid allocating
delayed extent ops structures when using the skinny metadata feature
and there's no relocation going on. This also gets rid of a BUG_ON().
For example, for a fs_mark run, with 5 iterations, 8 threads and 100K
files per iteration, before this patch there were 118109 allocations
of delayed extent op structures and after it there were none.
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Instead of doing a BUG_ON() handle the error by returning -EUCLEAN,
aborting the transaction and logging an error message.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Instead of using an if-else statement when processing the extent item at
btrfs_lookup_extent_info(), use a single if statement for the error case
since it does a goto at the end and leave the success (expected) case
following the if statement, reducing indentation and making the logic a
bit easier to follow. Also make the if statement's condition as unlikely
since it's not expected to ever happen, as it signals some corruption,
making it clear and hint the compiler to generate more efficient code.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If we didn't found an extent item with the initial btrfs_search_slot()
call, it's pointless to test if the "metadata" variable is "true", because
right after we check if the key type is BTRFS_METADATA_ITEM_KEY and that
is the case only when "metadata" is set to "true". So remove the redundant
check.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are no callers of btrfs_lookup_extent_info() that pass a NULL value
for the transaction handle argument, so there's no point in having special
logic to deal with the NULL. The last caller that passed a NULL value was
removed in commit 19b546d7a1 ("btrfs: relocation:
Use btrfs_find_all_leafs to locate data extent parent tree leaves").
So remove the NULL handling from btrfs_lookup_extent_info().
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When freeing a tree block, at btrfs_free_tree_block(), if we fail to
create a delayed reference we don't deal with the error and just do a
BUG_ON(). The error most likely to happen is -ENOMEM, and we have a
comment mentioning that only -ENOMEM can happen, but that is not true,
because in case qgroups are enabled any error returned from
btrfs_qgroup_trace_extent_post() (can be -EUCLEAN or anything returned
from btrfs_search_slot() for example) can be propagated back to
btrfs_free_tree_block().
So stop doing a BUG_ON() and return the error to the callers and make
them abort the transaction to prevent leaking space. Syzbot was
triggering this, likely due to memory allocation failure injection.
Reported-by: syzbot+a306f914b4d01b3958fe@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/000000000000fcba1e05e998263c@google.com/
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Snapshot delete has some complicated looking code that is weirdly subtle
at times. I've cleaned it up the best I can without re-writing it, but
there are still a lot of details that are non-obvious. Add a bunch of
comments to the main parts of the code to help future developers better
understand the mechanics of snapshot deletion.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In walk_up_proc() we BUG_ON(ret) from btrfs_dec_ref(). This is
incorrect, we have proper error handling here, return the error.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In walk_up_proc() we have several sanity checks that should only trip if
the programmer made a mistake. Convert these to ASSERT()'s instead of
BUG_ON()'s.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In reada we BUG_ON(refs == 0), which could be unkind since we aren't
holding a lock on the extent leaf and thus could get a transient
incorrect answer. In walk_down_proc we also BUG_ON(refs == 0), which
could happen if we have extent tree corruption. Change that to return
-EUCLEAN. In do_walk_down() we catch this case and handle it correctly,
however we return -EIO, which -EUCLEAN is a more appropriate error code.
Finally in walk_up_proc we have the same BUG_ON(refs == 0), so convert
that to proper error handling. Also adjust the error message so we can
actually do something with the information.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have a couple of areas where we check to make sure the tree block is
locked before looking up or messing with references. This is old code
so it has this as BUG_ON(). Convert this to ASSERT() for developers.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have blanket BUG_ON(ret) after every one of these reference mod
attempts, which is just incorrect. If we encounter any errors during
walk_down_tree() we will abort, so abort on any one of these failures.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We handle errors here properly, ENOMEM isn't fatal, return the error.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is a big chunk of code in do_walk_down() that will conditionally
remove the reference for the child block we're currently evaluating.
Extract it out into it's own helper and call that from do_walk_down()
instead.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We currently duplicate the logic for walking into a node during snapshot
delete. In one case it is during the actual delete, and in the other we
use it for deciding if we should reada the block or not.
Factor this code into it's own helper and comment fully what we're
doing, and then update the two users to use the new helper.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We only set this if wc->refs[level - 1] > 1, and we check this way up
above where we need it because the first thing we do before dropping our
refs is reset wc->refs[level - 1] to 0. Reorder resetting of wc->refs
to after our drop logic, and then remove the need_account variable and
simply check wc->refs[level - 1] directly instead of using a variable.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
do_walk_down() already has a bunch of things going on, and there's a bit
of code related to reading in the next eb if we decide we need it. Move
this code off into it's own helper to clean up do_walk_down() a little
bit.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Instead of using a flag we're passing around everywhere, add a field to
walk_control that we're already passing around everywhere and use that
instead.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently if our extent buffer isn't uptodate we will drop the lock,
free it, and then call read_tree_block() for the bytenr. This is
inefficient, we already have the extent buffer, we can simply call
btrfs_read_extent_buffer().
Merge these two cases down into one if statement, if we are not uptodate
we can drop the lock, trigger readahead, and do the read using
btrfs_read_extent_buffer(), and carry on.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We do find_extent_buffer(), and then if we don't find the eb in cache we
call btrfs_find_create_tree_block(), which calls find_extent_buffer()
first and then allocates the extent buffer.
The reason we're doing this is because if we don't find the extent
buffer in cache we set reada = 1. However this doesn't matter, because
lower down we only trigger reada if !btrfs_buffer_uptodate(eb), which is
what the case would be if we didn't find the extent buffer in cache and
had to allocate it.
Clean this up to simply call btrfs_find_create_tree_block(), and then
use the fact that we're having to read the extent buffer off of disk to
go ahead and kick off readahead.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Drop the variable 'err', reuse the variable 'ret' by reinitializing it to
zero where necessary.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently if we fully clean a subvolume (not only delete its directory,
but fully clean all it's related data and root item), the associated
qgroup would not be removed.
We have "btrfs qgroup clear-stale" to handle such 0 level qgroups.
Change the behavior to automatically removie the qgroup of a fully
cleaned subvolume when possible:
- Full qgroup but still consistent
We can and should remove the qgroup.
The qgroup numbers should be 0, without any rsv.
- Full qgroup but inconsistent
Can happen with drop_subtree_threshold feature (skip accounting
and mark qgroup inconsistent).
We can and should remove the qgroup.
Higher level qgroup numbers will be incorrect, but since qgroup
is already inconsistent, it should not be a problem.
- Squota mode
This is the special case, we can only drop the qgroup if its numbers
are all 0.
This would be handled by can_delete_qgroup(), so we only need to check
the return value and ignore the -EBUSY error.
Link: https://bugzilla.suse.com/show_bug.cgi?id=1222847
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
At lookup_extent_data_ref() we are incorrectly checking if we are at the
last slot of the last leaf in the extent tree. We are returning -ENOENT
if btrfs_next_leaf() returns a value greater than 1, but btrfs_next_leaf()
never returns anything greater than 1:
1) It returns < 0 on error;
2) 0 if there is a next leaf (or a new item was added to the end of the
current leaf after releasing the path);
3) 1 if there are no more leaves (and no new items were added to the last
leaf after releasing the path).
So fix this by checking if the return value is greater than zero instead
of being greater than one.
Fixes: 1618aa3c2e ("btrfs: simplify return variables in lookup_extent_data_ref()")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There's another return variable wret that is only passed to ret on
error, we can simply use ret.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
First, drop err instead reuse ret, choose to return the error instead of
goto fail and then return the same error. Do not initialize the ret
until where it has to be initialized. Slight logic change in handling
the btrfs_search_slot() and btrfs_next_leaf() return value.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A comment from Filipe on one of my previous cleanups brought my
attention to a new helper we have for getting the root id of a root,
which makes it easier to read in the code.
The changes where made with the following Coccinelle semantic patch:
// <smpl>
@@
expression E,E1;
@@
(
E->root_key.objectid = E1
|
- E->root_key.objectid
+ btrfs_root_id(E)
)
// </smpl>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ minor style fixups ]
Signed-off-by: David Sterba <dsterba@suse.com>
We only ever need to use this to get the level of the tree block ref, so
use the btrfs_delayed_ref_owner() helper, which returns the level for
the given reference.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that most of our elements are inside of btrfs_delayed_ref_node
directly and we have helpers for the delayed_data_ref bits, go ahead and
remove all direct usage of btrfs_delayed_data_ref and use the helpers
where needed.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We don't need to pass in all the elements for the backrefs as function
arguments, simply pass through the btrfs_delayed_ref_node and then
extract the values we need from that.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have all the information we need in our btrfs_delayed_ref_node, which
we already pass into __btrfs_free_extent. Drop the extra arguments and
just extract the values from btrfs_delayed_ref_node.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We're just extracting the values from btrfs_delayed_ref_node and passing
them through, simply pass the btrfs_delayed_ref_node into
__btrfs_inc_extent_ref and shrink the function arguments.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
These two members are shared by both the tree refs and data refs, so
move them into btrfs_delayed_ref_node proper. This allows us to greatly
simplify the comparison code, as the shared refs always only sort on
parent, and the non shared refs always sort first on ref_root, and then
only data refs sort on their specific fields.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We consistently use ->num_bytes everywhere through the delayed ref code,
except in btrfs_ref. Rename btrfs_ref to match all the other code.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that all of the delayed ref information is in the delayed ref node,
drastically simplify the delayed ref tracepoints by simply passing in
the btrfs_delayed_ref_node and populating the tracepoints with the
values from the structure itself.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have this in both btrfs_tree_ref and btrfs_data_ref, which is just
wasting space and making the code more complicated. Move this into
btrfs_ref proper and update all the call sites to do the assignment in
btrfs_ref.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_ref currently has ->owning_root, and ->ref_root is shared between
the tree ref and data ref, so in order to move that into btrfs_ref
proper I would need to add another root parameter to the initialization
function. This function has too many arguments, and adding another root
will make it easy to make mistakes about which root goes where.
Drop the generic ref init function and statically initialize the
btrfs_ref in every usage. This makes the code easier to read because we
can see what elements we're assigning, and will make the upcoming change
moving the ref_root into the btrfs_ref more clear and less error prone
than adding a new element to the initialization function.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The __btrfs_tree_lock() and __btrfs_tree_read_lock() are using a naming
with a double underscore prefix, which is specially not proper for
exported functions. Remove the double underscore prefix from their name
and add the "_nested" suffix.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add an ASSERT to catch a faulty delayed reference item resulting from
prematurely cleared extent buffer.
Also, add a WARN to detect if we try to dirty a ZEROOUT buffer again, which
is suspicious as its update will be lost.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
At btrfs_free_tree_block(), we are always initializing a delayed reference
to drop the given extent buffer but we only use if it does not belong to a
log root tree. So we are doing unnecessary work here and increasing the
duration of a critical section as this is normally called while holding a
lock on the parent tree block (if any) and while holding a log transaction
open.
So initialize the delayed reference only if the extent buffer is not from
a log tree, avoiding unnecessary work and making the code also a bit
easier to follow.
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The file extents are normally reserved in subvolume roots but could be
also in the data reloc tree. Change the BUG_ON to assertions as this
verifies the usage assumptions.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The check_committed_ref() helper looks up an extent item by a key,
allowing to do an inexact search when key->offset is -1. It's never
expected to find such item, as it would break the allowed range of a
extent item offset.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This helper is used in transaction abort or cleanup context and the
callers cannot handle all errors, only do best effort.
btrfs_cleanup_one_transaction
btrfs_destroy_delayed_refs
btrfs_error_unpin_extent_range
btrfs_destroy_pinned_extent
btrfs_error_unpin_extent_range
Signed-off-by: David Sterba <dsterba@suse.com>
Handle the lookup failure of the block group to unpin, this is a logic
error as the block group must exist at this point. If not, something else
must have freed it, like clean_pinned_extents() would do without locking
the unused_bg_unpin_mutex.
Push the errors to the callers, proper handling will be done in followup
patches.
Signed-off-by: David Sterba <dsterba@suse.com>
With help of neovim, LSP and clangd we can identify header files that
are not actually needed to be included in the .c files. This is focused
only on removal (with minor fixups), further cleanups are possible but
will require doing the header files properly with forward declarations,
minimized includes and include-what-you-use care.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There's a warning in btrfs_issue_discard() when the range is not aligned
to 512 bytes, originally added in 4d89d377bb ("btrfs:
btrfs_issue_discard ensure offset/length are aligned to sector
boundaries"). We can't do sub-sector writes anyway so the adjustment is
the only thing that we can do and the warning is unnecessary.
CC: stable@vger.kernel.org # 4.19+
Reported-by: syzbot+4a4f1eba14eb5c3417d1@syzkaller.appspotmail.com
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Writing sequentially to a huge file on btrfs on a SMR HDD revealed a
decline of the performance (220 MiB/s to 30 MiB/s after 500 minutes).
The performance goes down because of increased latency of the extent
allocation, which is induced by a traversing of a lot of full block groups.
So, this patch optimizes the ffe_ctl->hint_byte by choosing a block group
with sufficient size from the active block group list, which does not
contain full block groups.
After applying the patch, the performance is maintained well.
Fixes: 2eda57089e ("btrfs: zoned: implement sequential extent allocation")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Factor out prepare_allocation_zoned() for further extension. While at
it, optimize the if-branch a bit.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Reflow btrfs_free_tree_block() so that there is one level of indentation
needed.
This patch has no functional changes.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we're not clearing the dirty flag off of extent_buffers in zoned mode,
all that is left of btrfs_redirty_list_add() is a memzero() and some
ASSERT()ions.
As we're also memzero()ing the buffer on write-out btrfs_redirty_list_add()
has become obsolete and can be removed.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
EXTENT_BUFFER_ZONED_ZEROOUT better describes the state of the extent buffer,
namely it is written as all zeros. This is needed in zoned mode, to
preserve I/O ordering.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A reservation goes through a 3 step lifetime:
- generated during delalloc
- released/counted by ordered_extent allocation
- freed by running delayed ref
That third step depends on must_insert_reserved on the head ref, so the
head ref with that field set owns the reservation. Once you prepare to
run the head ref, must_insert_reserved is unset, which means that
running the ref must free the reservation, whether or not it succeeds,
or else the reservation is leaked. That results in either a risk of
spurious ENOSPC if the fs stays writeable or a warning on unmount if it
is readonly.
The existing squota code was aware of these invariants, but missed a few
cases. Improve it by adding a helper function to use in the cleanup
paths and call it from the existing early returns in running delayed
refs. This also simplifies btrfs_record_squota_delta and struct
btrfs_quota_delta.
This fixes (or at least improves the reliability of) generic/475 with
"mkfs -O squota". On my machine, that test failed ~4/10 times without
this patch and passed 100/100 times with it.
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Dave reported a bug where we were aborting the transaction while trying
to cleanup the squota reservation for an extent.
This turned out to be because we're doing btrfs_header_owner(next) in
do_walk_down when we decide to free the block. However in this code
block we haven't explicitly read next, so it could be stale. We would
then get whatever garbage happened to be in the pages at this point.
The commit that introduced that is "btrfs: track owning root in
btrfs_ref".
Fix this by saving the owner_root when we do the
btrfs_lookup_extent_info(). We always do this in do_walk_down, it is
how we make the decision of whether or not to delete the block. This is
cheap because we've already done the extent item lookup at this point,
so it's straightforward to just grab the owner root as well.
Then we can use this when deleting the metadata block without needing to
force a read of the extent buffer to find the owner.
This fixes the problem that Dave reported.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Relocation data allocations are quite tricky for simple quotas. The
basic data relocation sequence is (ignoring details that aren't relevant
to this fix):
- create a fake relocation data fs root
- create a fake relocation inode in that root
- for each data extent:
- preallocate a data extent on behalf of the fake inode
- copy over the data
- for each extent
- swap the refs so that the original file extent now refers to the new
extent item
- drop the fake root, dropping its refs on the old extents, which lets
us delete them.
Done naively, this results in storing an extent item in the extent tree
whose owner_ref points at the relocation data root and a no-op squota
recording, since the reloc root is not a legit fstree. So far, that's
OK. The problem comes when you do the swap, and leave an extent item
owned by this bogus root as the real permanent extents of the file. If
the file then drops that ref, we free it and no-op account that against
the fake relocation root. Essentially, this means that relocation is
simple quota "extent laundering", since we re-own the extents into a
fake root.
Simple quotas very intentionally doesn't have a mechanism for
transferring ownership of extents, as that is exactly the complicated
thing we are trying to avoid with the new design. Further, it cannot be
correctly done in this case, since at the time you create the new
"real" refs, there is no way to know which was the original owner before
relocation unless we track it.
Therefore, it makes more sense to trick the preallocation to handle
relocation as a special case and note the proper owner ref from the
beginning. That way, we never write out an extent item without the
correct owner ref that it will eventually have.
This could be done by wiring a special root parameter all the way
through the allocation code path, but to avoid that special case
touching all the code, take advantage of the serial nature of relocation
to store the src root on the relocation root object. Then when we finish
the prealloc, if it happens to be this case, prepare the delayed ref
appropriately.
We must also add logic to handle relocating adjacent extents with
different owning roots. Those cannot be preallocated together in a
cluster as it would lose the separate ownership information.
This is obviously a smelly bit of code, but I think it is the best
solution to the problem, given the relocation implementation.
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Relocation COWs metadata blocks in two cases for the reloc root:
- copying the subvolume root item when creating the reloc root
- copying a btree node when there is a COW during relocation
In both cases, the resulting btree node hits an abnormal code path with
respect to the owner field in its btrfs_header. It first creates the
root item for the new objectid, which populates the reloc root id, and
it at this point that delayed refs are created.
Later, it fully copies the old node into the new node (including the
original owner field) which overwrites it. This results in a simple
quotas mismatch where we run the delayed ref for the reloc root which
has no simple quota effect (reloc root is not an fstree) but when we
ultimately delete the node, the owner is the real original fstree and we
do free the space.
To work around this without tampering with the behavior of relocation,
add a parameter to btrfs_add_tree_block that lets the relocation code
path specify a different owning root than the "operating" root (in this
case, owning root is the real root and the operating root is the reloc
root). These can naturally be plumbed into delayed refs that have the
same concept.
Note that this is a double count in some sense, but a relatively natural
one, as there are really two extents, and the old one will be deleted
soon. This is consistent with how data relocation extents are accounted
by simple quotas.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Simple quotas count extents only from the moment the feature is enabled.
Therefore, if we do something like:
1. create subvol S
2. write F in S
3. enable quotas
4. remove F
5. write G in S
then after 3. and 4. we would expect the simple quota usage of S to be 0
(putting aside some metadata extents that might be written) and after
5., it should be the size of G plus metadata. Therefore, we need to be
able to determine whether a particular quota delta we are processing
predates simple quota enablement.
To do this, store the transaction id when quotas were enabled. In
fs_info for immediate use and in the quota status item to make it
recoverable on mount. When we see a delta, check if the generation of
the extent item is less than that of quota enablement. If so, we should
ignore the delta from this extent.
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
At the moment that we run delayed refs, we make the final ref-count
based decision on creating/removing extent (and metadata) items.
Therefore, it is exactly the spot to hook up simple quotas.
There are a few important subtleties to the fields we must collect to
accurately track simple quotas, particularly when removing an extent.
When removing a data extent, the ref could be in any tree (due to
reflink, for example) and so we need to recover the owning root id from
the owner ref item. When removing a metadata extent, we know the owning
root from the owner field in the header when we create the delayed ref,
so we can recover it from there.
We must also be careful to handle reservations properly to not leaked
reserved space. The happy path is freeing the reservation when the
simple quota delta runs on a data extent. If that doesn't happen, due to
refs canceling out or some error, the ref head already has the
must_insert_reserved machinery to handle this, so we piggy back on that
and use it to clean up the reserved data.
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Inline ref parsing is a bit tricky and relies on a decent amount of
implicit information, so I think it is beneficial to have a helper
function for reading the owner ref, if only to "document" the format,
along with the write path.
The main subtlety of note which I was missing by open-coding this was
that it is important to check whether or not inline refs are present
*at all*. i.e., if we are writing out a new extent under squotas, we
will always use a big enough item for the inline ref and have it.
However, it is possible that some random item predating squotas will not
have any inline refs. In that case, trying to read the "type" field of
the first inline ref will just be reading garbage in the form of
whatever is in the next item.
This will be used by the extent free-ing path, which looks up data
extent owners as well as a relocation path which needs to grab the owner
before relocating an extent.
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In order to implement simple quota groups, we need to be able to
associate a data extent with the subvolume that created it. Once you
account for reflink, this information cannot be recovered without
explicitly storing it. Options for storing it are:
- a new key/item
- a new extent inline ref item
The former is backwards compatible, but wastes space, the latter is
incompat, but is efficient in space and reuses the existing inline ref
machinery, while only abusing it a tiny amount -- specifically, the new
item is not a ref, per-se.
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
While data extents require us to store additional inline refs to track
the original owner on free, this information is available implicitly for
metadata. It is found in the owner field of the header of the tree
block. Even if other trees refer to this block and the original ref goes
away, we will not rewrite that header field, so it will reliably give the
original owner.
In addition, there is a relocation case where a new data extent needs to
have an owning root separate from the referring root wired through
delayed refs.
To use it for recording simple quota deltas, we need to wire this root
id through from when we create the delayed ref until we fully process
it. Store it in the generic btrfs_ref struct of the delayed ref.
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
commit 113479d5b8 ("btrfs: rename root fields in delayed refs structs")
changed these from ref_root to owning_root. However, there are many
circumstances where that name is not really accurate and the root on the
ref struct _is_ the referring root. In general, these are not the owning
root, though it does happen in some ref merging cases involving
overwrites during snapshots and similar.
Simple quotas cares quite a bit about tracking the original owner of an
extent through delayed refs, so rename these back to free up the name
for the real owning root (which will live on the generic btrfs_ref and
the head ref)
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
As each stripe extent is tied to an extent item, delete the stripe extent
once the corresponding extent item is deleted.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add support for inserting stripe extents into the raid stripe tree on
completion of every write that needs an extra logical-to-physical
translation when using RAID.
Inserting the stripe extents happens after the data I/O has completed,
this is done to
a) support zone-append and
b) rule out the possibility of a RAID-write-hole.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The comment on top of btrfs_pin_extent_for_log_replay() mentioning that
the function must be called within a transaction is pointless as of
commit 9fce570454 ("btrfs: Make btrfs_pin_extent_for_log_replay take
transaction handle"), since the function now takes a transaction handle
as its first argument. So remove the comment because it's completely
useless now.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A comment at btrfs_free_extent() mentions the call to btrfs_pin_extent()
unlocks the pinned mutex, however that mutex is long gone, it was removed
in 2009 by commit 04018de5d4 ("Btrfs: kill the pinned_mutex"). So just
delete the comment.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When marking an extent buffer as dirty, at btrfs_mark_buffer_dirty(),
we check if its generation matches the running transaction and if not we
just print a warning. Such mismatch is an indicator that something really
went wrong and only printing a warning message (and stack trace) is not
enough to prevent a corruption. Allowing a transaction to commit with such
an extent buffer will trigger an error if we ever try to read it from disk
due to a generation mismatch with its parent generation.
So abort the current transaction with -EUCLEAN if we notice a generation
mismatch. For this we need to pass a transaction handle to
btrfs_mark_buffer_dirty() which is always available except in test code,
in which case we can pass NULL since it operates on dummy extent buffers
and all test roots have a single node/leaf (root node at level 0).
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently when reserving space for deleting the csum items for a data
extent, when adding or updating a delayed ref head, we determine how
many leaves of csum items we can have and then pass that number to the
helper btrfs_calc_delayed_ref_bytes(). This helper is used for calculating
space for all tree modifications we need when running delayed references,
however the amount of space it computes is excessive for deleting csum
items because:
1) It uses btrfs_calc_insert_metadata_size() which is excessive because
we only need to delete csum items from the csum tree, we don't need
to insert any items, so btrfs_calc_metadata_size() is all we need (as
it computes space needed to delete an item);
2) If the free space tree is enabled, it doubles the amount of space,
which is pointless for csum deletion since we don't need to touch the
free space tree or any other tree other than the csum tree.
So improve on this by tracking how many csum deletions we have and using
a new helper to calculate space for csum deletions (just a wrapper around
btrfs_calc_metadata_size() with a comment). This reduces the amount of
space we need to reserve for csum deletions by a factor of 4, and it helps
reduce the number of times we have to block space reservations and have
the reclaim task enter the space flushing algorithm (flush delayed items,
flush delayed refs, etc) in order to satisfy tickets.
For example this results in a total time decrease when unlinking (or
truncating) files with many extents, as we end up having to block on space
metadata reservations less often. Example test:
$ cat test.sh
#!/bin/bash
DEV=/dev/nullb0
MNT=/mnt/test
umount $DEV &> /dev/null
mkfs.btrfs -f $DEV
# Use compression to quickly create files with a lot of extents
# (each with a size of 128K).
mount -o compress=lzo $DEV $MNT
# 100G gives at least 983040 extents with a size of 128K.
xfs_io -f -c "pwrite -S 0xab -b 1M 0 120G" $MNT/foobar
# Flush all delalloc and clear all metadata from memory.
umount $MNT
mount -o compress=lzo $DEV $MNT
start=$(date +%s%N)
rm -f $MNT/foobar
end=$(date +%s%N)
dur=$(( (end - start) / 1000000 ))
echo "rm took $dur milliseconds"
umount $MNT
Before this change rm took: 7504 milliseconds
After this change rm took: 6574 milliseconds (-12.4%)
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently when reserving space for delayed refs we do it on a per ref head
basis. This is generally enough because most back refs for an extent end
up being inlined in the extent item - with the default leaf size of 16K we
can have at most 33 inline back refs (this is calculated by the macro
BTRFS_MAX_EXTENT_ITEM_SIZE()). The amount of bytes reserved for each ref
head is given by btrfs_calc_delayed_ref_bytes(), which basically
corresponds to a single path for insertion into the extent tree plus
another path for insertion into the free space tree if it's enabled.
However if we have reached the limit of inline refs or we have a mix of
inline and non-inline refs, then we will need to insert a non-inline ref
and update the existing extent item to update the total number of
references for the extent. This implies we need reserved space for two
insertion paths in the extent tree, but we only reserved for one path.
The extent item and the non-inline ref item may be located in different
leaves, or even if they are located in the same leaf, after updating the
extent item and before inserting the non-inline ref item, the extent
buffers in the btree path may have been written (due to memory pressure
for e.g.), in which case we need to COW the entire path again. In this
case since we have not reserved enough space for the delayed refs block
reserve, we will use the global block reserve.
If we are in a situation where the fs has no more unallocated space enough
to allocate a new metadata block group and available space in the existing
metadata block groups is close to the maximum size of the global block
reserve (512M), we may end up consuming too much of the free metadata
space to the point where we can't commit any future transaction because it
will fail, with -ENOSPC, during its commit when trying to allocate an
extent for some COW operation (running delayed refs generated by running
delayed refs or COWing the root tree's root node at commit_cowonly_roots()
for example). Such dramatic scenario can happen if we have many delayed
refs that require the insertion of non-inline ref items, due to too many
reflinks or snapshots. We also have situations where we use the global
block reserve because we could not in advance know that we will need
space to update some trees (block group creation for example), so this
all adds up to increase the chances of exhausting the global block reserve
and making any future transaction commit to fail with -ENOSPC and turn
the fs into RO mode, or fail the mount operation in case the mount needs
to start and commit a transaction, such as when we have orphans to cleanup
for example - such case was reported and hit by someone running a SLE
(SUSE Linux Enterprise) distribution for example - where the fs had no
more unallocated space that could be used to allocate a new metadata block
group, and the available metadata space was about 1.5M, not enough to
commit a transaction to cleanup an orphan inode (or do relocation of data
block groups that were far from being full).
So reserve space for delayed refs by individual refs and not by ref heads,
as we may need to COW multiple extent tree paths due to non-inline ref
items.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When running delayed references, through btrfs_run_delayed_refs(), we can
specify how many to run, run all existing delayed references and keep
running delayed references while we can find any. This is controlled with
the value of the 'count' argument, where a value of 0 means to run all
delayed references that exist by the time btrfs_run_delayed_refs() is
called, (unsigned long)-1 means to keep running delayed references while
we are able find any, and any other value to run that exact number of
delayed references.
Typically a specific value other than 0 or -1 is used when flushing space
to try to release a certain amount of bytes for a ticket. In this case
we just simply calculate how many delayed reference heads correspond to a
specific amount of bytes, with calc_delayed_refs_nr(). However that only
takes into account the space reserved for the reference heads themselves,
and does not account for the space reserved for deleting checksums from
the csum tree (see add_delayed_ref_head() and update_existing_head_ref())
in case we are going to delete a data extent. This means we may end up
running more delayed references than necessary in case we process delayed
references for deleting a data extent.
So change the logic of btrfs_run_delayed_refs() to take a bytes argument
to specify how many bytes of delayed references to run/release, using the
special values of 0 to mean all existing delayed references and U64_MAX
(or (u64)-1) to keep running delayed references while we can find any.
This prevents running more delayed references than necessary, when we have
delayed references for deleting data extents, but also makes the upcoming
changes/patches simpler and it's preparatory work for them.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
At lookup_inline_extent_backref() we can simplify the check for an overrun
of the extent item by making the while loop's condition to be "ptr < end"
and then check after the loop if an overrun happened ("ptr > end"). This
reduces indentation and makes the loop condition more clear. So move the
check out of the loop and change the loop condition accordingly, while
also adding the 'unlikely' tag to the check since it's not supposed to be
triggered.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
At lookup_inline_extent_backref() when trying to insert an inline backref,
if we don't find the extent item we log an error and then return -EIO.
This error code is confusing because there was actually no IO error, and
this means we have some corruption, either caused by a bug or something
like a memory bitflip for example. So change the error code from -EIO to
-EUCLEAN.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
At lookup_inline_extent_backref(), instead of using a 'ret' and an 'err'
variable for tracking the return value, use a single one ('ret'). This
simplifies the code, makes it comply with most of the existing code and
it's less prone for logic errors as time has proven over and over in the
btrfs code.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Instead of using a 'ret' and an 'err' variable at run_delayed_extent_op()
for tracking the return value, use a single one ('ret'). This simplifies
the code, makes it comply with most of the existing code and it's less
prone for logic errors as time has proven over and over in the btrfs code.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The 'ref_root' variable, at run_delayed_data_ref(), is not really needed
as we can always use ref->root directly, plus its initialization to 0 is
completely pointless as we assign it ref->root before its first use.
So just drop that variable and use ref->root directly.
This may help avoid some warnings with clang tools such as the one
reported/fixed by commit 966de47ff0 ("btrfs: remove redundant
initialization of variables in log_new_ancestors").
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
At run_delayed_data_ref() we are always initializing a key but the key
is only needed and used if we are inserting a new extent. So move the
declaration and initialization of the key to 'if' branch where it's used.
Also rename the key from 'ins' to 'key', as it's a more clear name.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently the 'refs_to_drop' argument of __btrfs_free_extent() always
matches the value of node->ref_mod, so remove the argument and use
node->ref_mod at __btrfs_free_extent().
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently the 'refs_to_add' argument of __btrfs_inc_extent_ref() always
matches the value of node->ref_mod, so remove the argument and use
node->ref_mod at __btrfs_inc_extent_ref().
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When running delayed references, at btrfs_run_delayed_refs(), we have this
logic to run any new delayed references that might have been added just
after we ran all delayed references. This logic grabs the first delayed
reference, then locks it to wait for any contention on it before running
all new delayed references. This however is pointless and not necessary
because at __btrfs_run_delayed_refs() when we start running delayed
references, we pick the first reference with btrfs_obtain_ref_head() and
then we will lock it (with btrfs_delayed_ref_lock()).
So remove the duplicate and unnecessary logic at btrfs_run_delayed_refs().
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The lock_owner is used for a rare corruption case and we haven't seen
any reports in years. Move it to the debugging section of eb. To close
the holes also move log_index so the final layout looks like:
struct extent_buffer {
u64 start; /* 0 8 */
long unsigned int len; /* 8 8 */
long unsigned int bflags; /* 16 8 */
struct btrfs_fs_info * fs_info; /* 24 8 */
spinlock_t refs_lock; /* 32 4 */
atomic_t refs; /* 36 4 */
int read_mirror; /* 40 4 */
s8 log_index; /* 44 1 */
/* XXX 3 bytes hole, try to pack */
struct callback_head callback_head __attribute__((__aligned__(8))); /* 48 16 */
/* --- cacheline 1 boundary (64 bytes) --- */
struct rw_semaphore lock; /* 64 40 */
struct page * pages[16]; /* 104 128 */
/* size: 232, cachelines: 4, members: 11 */
/* sum members: 229, holes: 1, sum holes: 3 */
/* forced alignments: 1, forced holes: 1, sum forced holes: 3 */
/* last cacheline: 40 bytes */
} __attribute__((__aligned__(8)));
This saves 8 bytes in total and still keeps the lock on a separate cacheline.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Both callers of btrfs_pin_extent_for_log_replay expand the parameters to
extent buffer members. We can simply pass the extent buffer instead.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is only one caller of btrfs_pin_reserved_extent that expands the
parameters to extent buffer members. We can simply pass the extent
buffer instead.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Function name in the comment does not bring much value to code not
exposed as API and we don't stick to the kdoc format anymore. Update
formatting of parameter descriptions.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This simply sends the same arguments into crc32c(), and is just used in
a few places. Remove this wrapper and directly call crc32c() in these
instances.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When running a delayed extent operation, if we don't find the extent item
in the extent tree we just return -EIO without any logged message. This
indicates some bug or possibly a memory or fs corruption, so the return
value should not be -EIO but -EUCLEAN instead, and since it's not expected
to ever happen, print an informative error message so that if it happens
we have some idea of what went wrong, where to look at.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
At __btrfs_inc_extent_ref() we are doing a BUG_ON() if we are dealing with
a tree block reference that has a reference count that is different from 1,
but we have already dealt with this case at run_delayed_tree_ref(), making
it useless. So remove the BUG_ON().
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When running a delayed tree reference, if we find a ref count different
from 1, we return -EIO. This isn't an IO error, as it indicates either a
bug in the delayed refs code or a memory corruption, so change the error
code from -EIO to -EUCLEAN. Also tag the branch as 'unlikely' as this is
not expected to ever happen, and change the error message to print the
tree block's bytenr without the parenthesis (and there was a missing space
between the 'block' word and the opening parenthesis), for consistency as
that's the style we used everywhere else.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The v0 extent item has been deprecated for a long time, and we don't have
any report from the community either.
So it's time to remove the v0 extent specific error handling, and just
treat them as regular extent tree corruption.
This patch would remove the btrfs_print_v0_err() helper, and enhance the
involved error handling to treat them just as any extent tree
corruption. No reports regarding v0 extents have been seen since the
graceful handling was added in 2018.
This involves:
- btrfs_backref_add_tree_node()
This change is a little tricky, the new code is changed to only handle
BTRFS_TREE_BLOCK_REF_KEY and BTRFS_SHARED_BLOCK_REF_KEY.
But this is safe, as we have rejected any unknown inline refs through
btrfs_get_extent_inline_ref_type().
For keyed backrefs, we're safe to skip anything we don't know (that's
if it can pass tree-checker in the first place).
- btrfs_lookup_extent_info()
- lookup_inline_extent_backref()
- run_delayed_extent_op()
- __btrfs_free_extent()
- add_tree_block()
Regular error handling of unexpected extent tree item, and abort
transaction (if we have a trans handle).
- remove_extent_data_ref()
It's pretty much the same as the regular rejection of unknown backref
key.
But for this particular case, we can also remove a BUG_ON().
- extent_data_ref_count()
We can remove the BTRFS_EXTENT_REF_V0_KEY BUG_ON(), as it would be
rejected by the only caller.
- btrfs_print_leaf()
Remove the handling for BTRFS_EXTENT_REF_V0_KEY.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
Syzbot reported several warning triggered inside
lookup_inline_extent_backref().
[CAUSE]
As usual, the reproducer doesn't reliably trigger locally here, but at
least we know the WARN_ON() is triggered when an inline backref can not
be found, and it can only be triggered when @insert is true. (I.e.
inserting a new inline backref, which means the backref should already
exist)
[ENHANCEMENT]
After the WARN_ON(), dump all the parameters and the extent tree
leaf to help debug.
Link: https://syzkaller.appspot.com/bug?extid=d6f9ff86c1d804ba2bc6
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When multiple writes happen at once, we may need to sacrifice a currently
active block group to be zone finished for a new allocation. We choose a
block group with the least free space left, and zone finish it.
To do the finishing, we need to send IOs for already allocated region
and wait for them and on-going IOs. Otherwise, these IOs fail because the
zone is already finished at the time the IO reach a device.
However, if a block group dedicated to the data relocation is zone
finished, there is a chance that finishing it before an ongoing write IO
reaches the device. That is because there is timing gap between an
allocation is done (block_group->reservations == 0, as pre-allocation is
done) and an ordered extent is created when the relocation IO starts.
Thus, if we finish the zone between them, we can fail the IOs.
We cannot simply use "fs_info->data_reloc_bg == block_group->start" to
avoid the zone finishing. Because, the data_reloc_bg may already switch to
a new block group, while there are still ongoing write IOs to the old
data_reloc_bg.
So, this patch reworks the BLOCK_GROUP_FLAG_ZONED_DATA_RELOC bit to
indicate there is a data relocation allocation and/or ongoing write to the
block group. The bit is set on allocation and cleared in end_io function of
the last IO for the currently allocated region.
To change the timing of the bit setting also solves the issue that the bit
being left even after there is no IO going on. With the current code, if
the data_reloc_bg switches after the last IO to the current data_reloc_bg,
the bit is set at this timing and there is no one clearing that bit. As a
result, that block group is kept unallocatable for anything.
Fixes: 343d8a3085 ("btrfs: zoned: prevent allocation from previous data relocation BG")
Fixes: 74e91b12b1 ("btrfs: zoned: zone finish unused block group")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
My initial fix for the generic/475 hangs was related to metadata, but
our CI testing uncovered another case where we hang for similar reasons.
We again have a task with a plug that is holding an outstanding request
that is keeping the dm device from finishing it's suspend, and that task
is stuck in the allocator.
This time it is stuck trying to allocate data, but we do not have a
block group that matches the size class. The larger loop in the
allocator looks like this (simplified of course)
find_free_extent
for_each_block_group {
ffe_ctl->cached == btrfs_block_group_cache_done(bg)
if (!ffe_ctl->cached)
ffe_ctl->have_caching_bg = true;
do_allocation()
btrfs_wait_block_group_cache_progress();
}
if (loop == LOOP_CACHING_WAIT && ffe_ctl->have_caching_bg)
go search again;
In my earlier fix we were trying to allocate from the block group, but
we weren't waiting for the progress because we were only waiting for the
free space to be >= the amount of free space we wanted. My fix made it
so we waited for forward progress to be made as well, so we would be
sure to wait.
This time however we did not have a block group that matched our size
class, so what was happening was this
find_free_extent
for_each_block_group {
ffe_ctl->cached == btrfs_block_group_cache_done(bg)
if (!ffe_ctl->cached)
ffe_ctl->have_caching_bg = true;
if (size_class_doesn't_match())
goto loop;
do_allocation()
btrfs_wait_block_group_cache_progress();
loop:
release_block_group(block_group);
}
if (loop == LOOP_CACHING_WAIT && ffe_ctl->have_caching_bg)
go search again;
The size_class_doesn't_match() part was true, so we'd just skip this
block group and never wait for caching, and then because we found a
caching block group we'd just go back and do the loop again. We never
sleep and thus never flush the plug and we have the same deadlock.
Fix the logic for waiting on the block group caching to instead do it
unconditionally when we goto loop. This takes the logic out of the
allocation step, so now the loop looks more like this
find_free_extent
for_each_block_group {
ffe_ctl->cached == btrfs_block_group_cache_done(bg)
if (!ffe_ctl->cached)
ffe_ctl->have_caching_bg = true;
if (size_class_doesn't_match())
goto loop;
do_allocation()
btrfs_wait_block_group_cache_progress();
loop:
if (loop > LOOP_CACHING_NOWAIT && !ffe_ctl->retry_uncached &&
!ffe_ctl->cached) {
ffe_ctl->retry_uncached = true;
btrfs_wait_block_group_cache_progress();
}
release_block_group(block_group);
}
if (loop == LOOP_CACHING_WAIT && ffe_ctl->have_caching_bg)
go search again;
This simplifies the logic a lot, and makes sure that if we're hitting
uncached block groups we're always waiting on them at some point.
I ran this through 100 iterations of generic/475, as this particular
case was harder to hit than the previous one.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
