linux.git/fs/btrfs/relocation.c, branch v6.10

btrfs: handle errors in btrfs_reloc_clone_csums properly

2024-05-07T19:31:09+00:00

In the cow path we will clone the reloc csums for relocated data
extents, and if there's an error we already have an ordered extent and
rely on the ordered extent finishing to clean everything up.

There's a problem however, we don't mark the ordered extent with an
error, we pretend like everything was just fine.  If we were at the end
of our range we won't actually bubble up this error anywhere, and we
could end up inserting an extent that doesn't have csums where it should
have them.

Fix this by adding a helper to mark the ordered extent with an error,
and then use this when we fail to lookup the csums in
btrfs_reloc_clone_csums.  Use this helper in the other place where we
use the same pattern while we're here.

This will prevent us from erroneously inserting the extent that doesn't
have the required checksums.

Reviewed-by: Johannes Thumshirn 
Signed-off-by: Josef Bacik 
Signed-off-by: David Sterba

btrfs: drop unused argument of calcu_metadata_size()

2024-05-07T19:31:08+00:00

calcu_metadata_size() has a "reserve" argument, but the only caller always
set it to "1". The other usage (reserve = 0) is dropped by a commit
0647bf564f1e ("Btrfs: improve forever loop when doing balance relocation"),
which is more than 10 years ago. Drop the argument and simplify the code.

Reviewed-by: Qu Wenruo 
Reviewed-by: Johannes Thumshirn 
Signed-off-by: Naohiro Aota 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: reuse ret instead of err in relocate_tree_blocks()

2024-05-07T19:31:08+00:00

Coding style fixes the function relocate_tree_blocks().  After the fix,
ret is the return value variable.

Signed-off-by: Anand Jain 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: rename err and ret to ret in build_backref_tree()

2024-05-07T19:31:08+00:00

Code style fix in the function build_backref_tree().  Drop the ret
initialization 0, as we don't need it.

Signed-off-by: Anand Jain 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: change root->root_key.objectid to btrfs_root_id()

2024-05-07T19:31:06+00:00

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:

// 
@@
expression E,E1;
@@
(
 E->root_key.objectid = E1
|
- E->root_key.objectid
+ btrfs_root_id(E)
)
// 

Reviewed-by: Filipe Manana 
Signed-off-by: Josef Bacik 
Reviewed-by: David Sterba 
[ minor style fixups ]
Signed-off-by: David Sterba

btrfs: rename ->len to ->num_bytes in btrfs_ref

2024-05-07T19:31:05+00:00

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 
Signed-off-by: Josef Bacik 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: move ref_root into btrfs_ref

2024-05-07T19:31:04+00:00

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 
Signed-off-by: Josef Bacik 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: do not use a function to initialize btrfs_ref

2024-05-07T19:31:04+00:00

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 
Signed-off-by: Josef Bacik 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: export find_next_inode() as btrfs_find_first_inode()

2024-05-07T19:31:04+00:00

Export the relocation private helper find_next_inode() to inode.c, as this
same logic is also used at btrfs_prune_dentries() and will be used by an
upcoming change that adds an extent map shrinker. The next patch will
change btrfs_prune_dentries() to use this helper.

Reviewed-by: Qu Wenruo 
Reviewed-by: Josef Bacik 
Signed-off-by: Filipe Manana 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: make NOCOW checks for existence of checksums in a range more efficient

2024-05-07T19:31:03+00:00

Before deciding if we can do a NOCOW write into a range, one of the things
we have to do is check if there are checksum items for that range. We do
that through the btrfs_lookup_csums_list() function, which searches for
checksums and adds them to a list supplied by the caller.

But all we need is to check if there is any checksum, we don't need to
look for all of them and collect them into a list, which requires more
search time in the checksums tree, allocating memory for checksums items
to add to the list, copy checksums from a leaf into those list items,
then free that memory, etc. This is all unnecessary overhead, wasting
mostly CPU time, and perhaps some occasional IO if we need to read from
disk any extent buffers.

So change btrfs_lookup_csums_list() to allow to return immediately in
case it finds any checksum, without the need to add it to a list and read
it from a leaf. This is accomplished by allowing a NULL list parameter and
making the function return 1 if it found any checksum, 0 if it didn't
found any, and a negative value in case of an error.

The following test with fio was used to measure performance:

  $ cat test.sh
  #!/bin/bash

  DEV=/dev/nullb0
  MNT=/mnt/nullb0

  cat < /tmp/fio-job.ini
  [global]
  name=fio-rand-write
  filename=$MNT/fio-rand-write
  rw=randwrite
  bssplit=4k/20:8k/20:16k/20:32k/20:64k/20
  direct=1
  numjobs=16
  fallocate=posix
  time_based
  runtime=300

  [file1]
  size=8G
  ioengine=io_uring
  iodepth=16
  EOF

  umount $MNT &> /dev/null
  mkfs.btrfs -f $DEV
  mount -o ssd $DEV $MNT

  fio /tmp/fio-job.ini
  umount $MNT

The test was run on a release kernel (Debian's default kernel config).

The results before this patch:

  WRITE: bw=139MiB/s (146MB/s), 8204KiB/s-9504KiB/s (8401kB/s-9732kB/s), io=17.0GiB (18.3GB), run=125317-125344msec

The results after this patch:

  WRITE: bw=153MiB/s (160MB/s), 9241KiB/s-10.0MiB/s (9463kB/s-10.5MB/s), io=17.0GiB (18.3GB), run=114054-114071msec

Reviewed-by: Qu Wenruo 
Signed-off-by: Filipe Manana 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba