Currently scrub_raid56_parity() has a large double loop, handling the
following things at the same time:
- Iterate each data stripe
- Iterate each extent item in one data stripe
Refactor this by:
- Introduce a new helper to handle data stripe iteration
The new helper is scrub_raid56_data_stripe_for_parity(), which
only has one while() loop handling the extent items inside the
data stripe.
The code is still mostly the same as the old code.
- Call cond_resched() for each extent
Previously we only call cond_resched() under a complex if () check.
I see no special reason to do that, and for other scrub functions,
like scrub_simple_mirror() we're already doing the same cond_resched()
after scrubbing one extent.
- Add more comments
Please note that, this patch is only to address the double loop, there
are incoming patches to do extra cleanup.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Although RAID56 has complex repair mechanism, which involves reading the
whole full stripe, but inside one data stripe, it's in fact no different
than SINGLE/RAID1.
The point here is, for data stripe we just check the csum for each
extent we hit. Only for csum mismatch case, our repair paths divide.
So we can still reuse scrub_simple_mirror() for RAID56 data stripes,
which saves quite some code.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since we have moved all other profiles handling into their own
functions, now the main body of scrub_stripe() is just handling RAID56
profiles.
There is no need to address other profiles in the main loop of
scrub_stripe(), so we can remove those dead branches.
Since we're here, also slightly change the timing of initialization of
variables like @offset, @increment and @logical.
Especially for @logical, we don't really need to initialize it for
btrfs_extent_root()/btrfs_csum_root(), we can use bg->start for that
purpose.
Now those variables are only initialize for RAID56 branches.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The new entrance will iterate through each data stripe which belongs to
the target device.
And since inside each data stripe, RAID0 is just SINGLE, while RAID10 is
just RAID1, we can reuse scrub_simple_mirror() to do the scrub properly.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The new helper, scrub_simple_mirror(), will scrub all extents inside a
range which only has simple mirror based duplication.
This covers every range of SINGLE/DUP/RAID1/RAID1C*, and inside each
data stripe for RAID0/RAID10.
Currently we will use this function to scrub SINGLE/DUP/RAID1/RAID1C*
profiles. As one can see, the new entrance for those simple-mirror
based profiles can be small enough (with comments, just reach 100
lines).
This function will be the basis for the incoming scrub refactor.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The new helper, find_first_extent_item(), will locate an extent item
(either EXTENT_ITEM or METADATA_ITEM) which covers any byte of the
search range.
This helper will later be used to refactor scrub code.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The variable @physical_end is the exclusive stripe end, currently it's
calculated using @physical + @dev_extent_len / map->stripe_len *
map->stripe_len.
And since at allocation time we ensured dev_extent_len is stripe_len
aligned, the result is the same as @physical + @dev_extent_len.
So this patch will just assign @physical and @physical_end early,
without using @nstripes.
This is especially helpful for any possible out: label user, as now we
only need to initialize @offset before going to out: label.
Since we're here, also make @physical_end constant.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
… rename it to simply fs_roots and adjust all usages of this object to use
the XArray API, because it is notionally easier to use and understand, as
it provides array semantics, and also takes care of locking for us,
further simplifying the code.
Also do some refactoring, esp. where the API change requires largely
rewriting some functions, anyway.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Gabriel Niebler <gniebler@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
… named 'extent_buffers'. Also adjust all usages of this object to use
the XArray API, which greatly simplifies the code as it takes care of
locking and is generally easier to use and understand, providing
notionally simpler array semantics.
Also perform some light refactoring.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Gabriel Niebler <gniebler@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
… and adjust all usages of this object to use the XArray API for the sake
of consistency.
XArray API provides array semantics, so it is notionally easier to use and
understand, and it also takes care of locking for us.
None of this makes a real difference in this particular patch, but it does
in other places where similar replacements are or have been made and we
want to be consistent in our usage of data structures in btrfs.
Signed-off-by: Gabriel Niebler <gniebler@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
… in the btrfs_root struct and adjust all usages of this object to use
the XArray API, because it is notionally easier to use and understand,
as it provides array semantics, and also takes care of locking for us,
further simplifying the code.
Also use the opportunity to do some light refactoring.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Gabriel Niebler <gniebler@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In function btrfs_bg_flags_to_raid_index(), we use quite some if () to
convert the BTRFS_BLOCK_GROUP_* bits to a index number.
But the truth is, there is really no such need for so many branches at
all.
Since all BTRFS_BLOCK_GROUP_* flags are just one single bit set inside
BTRFS_BLOCK_GROUP_PROFILES_MASK, we can easily use ilog2() to calculate
their values.
This calculation has an anchor point, the lowest PROFILE bit, which is
RAID0.
Even it's fixed on-disk format and should never change, here I added
extra compile time checks to make it super safe:
1. Make sure RAID0 is always the lowest bit in PROFILE_MASK
This is done by finding the first (least significant) bit set of
RAID0 and PROFILE_MASK & ~RAID0.
2. Make sure RAID0 bit set beyond the highest bit of TYPE_MASK
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It's only internally used as another way to represent btrfs profiles,
it's not exposed through any on-disk format, in fact this
btrfs_raid_types is diverted from the on-disk format values.
Furthermore, since it's internal structure, its definition can change in
the future.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
rmw_workers doesn't need ordered execution or thread disabling threshold
(as the thresh parameter is less than DFT_THRESHOLD).
Just switch to the normal workqueues that use a lot less resources,
especially in the work_struct vs btrfs_work structures.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
All three scrub workqueues don't need ordered execution or thread
disabling threshold (as the thresh parameter is less than DFT_THRESHOLD).
Just switch to the normal workqueues that use a lot less resources,
especially in the work_struct vs btrfs_work structures.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Just let the one caller that wants optional WQ_HIGHPRI handling allocate
a separate btrfs_workqueue for that. This allows to rename struct
__btrfs_workqueue to btrfs_workqueue, remove a pointer indirection and
separate allocation for all btrfs_workqueue users and generally simplify
the code.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now the btrfs RAID56 infrastructure has migrated to use sector_ptr
interface, it should be safe to enable subpage support for RAID56.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The non-compatible part is only the bitmap iteration part, now the
bitmap size is extended to rbio::stripe_nsectors, not the old
rbio::stripe_npages.
Since we're here, also slightly improve the function by:
- Rename @i to @stripe
- Rename @bit to @sectornr
- Move @page and @index into the inner loop
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Function steal_rbio() will take all the uptodate pages from the source
rbio to destination rbio.
With the new stripe_sectors[] array, we also need to do the extra check:
- Check sector::flags to make sure the full page is uptodate
Now we don't use PageUptodate flag for subpage cases to indicate
if the page is uptodate.
Instead we need to check all the sectors belong to the page to be sure
about whether it's full page uptodate.
So here we introduce a new helper, full_page_sectors_uptodate() to do
the check.
- Update rbio::stripe_sectors[] to use the new page pointer
We only need to change the page pointer, no need to change anything
else.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Unlike previous code, we can not directly set PageUptodate for stripe
pages now. Instead we have to iterate through all the sectors and set
SECTOR_UPTODATE flag there.
Introduce a new helper find_stripe_sector(), to do the work.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The functionality is completely replaced by the new bio_sectors member,
now it's time to remove the old member.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This requires one extra parameter @pgoff for the function.
In the current code base, scrub is still one page per sector, thus the
new parameter will always be 0.
It needs the extra subpage scrub optimization code to fully take
advantage.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is only one caller for that helper now, and we're definitely fine
to open-code it.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
With this function converted to subpage compatible sector interfaces,
the following helper functions can be removed:
- rbio_stripe_page()
- rbio_pstripe_page()
- rbio_qstripe_page()
- page_in_rbio()
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This involves:
- Use sector_ptr interface to grab the pointers
- Add sector->pgoff to pointers[]
- Rebuild data using sectorsize instead of PAGE_SIZE
- Use memcpy() to replace copy_page()
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The core is to convert direct page usage into sector_ptr usage, and
use memcpy() to replace copy_page().
For pointers usage, we need to convert it to kmap_local_page() +
sector->pgoff.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Make rbio_add_io_page() subpage compatible, which involves:
- Rename rbio_add_io_page() to rbio_add_io_sector()
Although we still rely on PAGE_SIZE == sectorsize, so add a new
ASSERT() inside rbio_add_io_sector() to make sure all pgoff is 0.
- Introduce rbio_stripe_sector() helper
The equivalent of rbio_stripe_page().
This new helper has extra ASSERT()s to validate the stripe and sector
number.
- Introduce sector_in_rbio() helper
The equivalent of page_in_rbio().
- Rename @pagenr variables to @sectornr
- Use rbio::stripe_nsectors when iterating the bitmap
Please note that, this only changes the interface, the bios are still
using full page for IO.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This new member is going to fully replace bio_pages in the future, but
for now let's keep them co-exist, until the full switch is done.
Currently cache_rbio_pages() and index_rbio_pages() will also populate
the new array.
And cache_rbio_pages() need to record which sectors are uptodate, so we
also need to introduce sector_ptr::uptodate bit.
To avoid extra memory usage, we let the new @uptodate bit to share bits
with @pgoff. Now pgoff only has at most 31 bits, which is already more
than enough, as even for 256K page size, we only need 18 bits.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The new member is an array of sector_ptr pointers, they will represent
all sectors inside a full stripe (including P/Q).
They co-operate with btrfs_raid_bio::stripe_pages:
stripe_pages: | Page 0, range [0, 64K) | Page 1 ...
stripe_sectors: | | | ... | |
| | \- sector 15, page 0, pgoff=60K
| \- sector 1, page 0, pgoff=4K
\---- sector 0, page 0, pfoff=0
With such structure, we can represent subpage sectors without using
extra pages.
Here we introduce a new helper, index_stripe_sectors(), to update
stripe_sectors[] to point to correct page and pgoff.
So every time rbio::stripe_pages[] pointer gets updated, the new helper
should be called.
The following functions have to call the new helper:
- steal_rbio()
- alloc_rbio_pages()
- alloc_rbio_parity_pages()
- alloc_rbio_essential_pages()
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The new members are all related to number of sectors, but the existing
number of pages members are kept as is:
- nr_sectors
Total sectors of the full stripe including P/Q.
- stripe_nsectors
The sectors of a single stripe.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are a lot of members using much larger type in btrfs_raid_bio than
necessary, like nr_pages which represents the total number of a full
stripe.
Instead of int (which is at least 32bits), u16 is already enough
(max stripe length will be 256MiB, already beyond current RAID56 device
number limit).
So this patch will reduce the width of the following members:
- stripe_len to u32
- nr_pages to u16
- nr_data to u8
- real_stripes to u8
- scrubp to u8
- faila/b to s8
As -1 is used to indicate no corruption
This will slightly reduce the size of btrfs_raid_bio from 272 bytes to
256 bytes, reducing 16 bytes usage.
But please note that, when using btrfs_raid_bio, we allocate extra space
for it to cover various pointer array, so the reduce memory is not
really a big saving overall.
As we're here modifying the comments already, update existing comments
to current code standard.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The function rbio_nr_pages() is only called once inside alloc_rbio(),
there is no reason to make it dedicated helper.
Furthermore, the return type doesn't match, the function return "unsigned
long" which may not be necessary, while the only caller only uses "int".
Since we're doing cleaning up here, also fix the type to "const unsigned
int" for all involved local variables.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently btrfs uses fixed stripe length (64K), thus u32 is wide enough
for the usage.
Furthermore, even in the future we choose to enlarge stripe length to
larger values, I don't believe we would want stripe as large as 4G or
larger.
So this patch will reduce the width for all in-memory structures and
parameters, this involves:
- RAID56 related function argument lists
This allows us to do direct division related to stripe_len.
Although we will use bits shift to replace the division anyway.
- btrfs_io_geometry structure
This involves one change to simplify the calculation of both @stripe_nr
and @stripe_offset, using div64_u64_rem().
And add extra sanity check to make sure @stripe_offset is always small
enough for u32.
This saves 8 bytes for the structure.
- map_lookup structure
This convert @stripe_len to u32, which saves 8 bytes. (saved 4 bytes,
and removed a 4-bytes hole)
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Both btrfs_repair_one_sector and submit_bio_one as the direct caller of
one of the instances ignore errors as they expect the methods themselves
to call ->bi_end_io on error. Remove the unused and dangerous return
value.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_submit_compressed_read already calls ->bi_end_io on error and
the caller must ignore the return value, so remove it.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_submit_metadata_bio already calls ->bi_end_io on error and the
caller must ignore the return value, so remove it.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This argument is unused since commit 953651eb30 ("btrfs: factor out
helper adding a page to bio") and commit 1b36294a6c ("btrfs: call
submit_bio_hook directly for metadata pages") reworked the way metadata
bio submission is handled.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Keep btrfs_readpage next to btrfs_do_readpage and the other address
space operations. This allows to keep submit_one_bio and
struct btrfs_bio_ctrl file local in extent_io.c.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
There is a report that a btrfs has a bad super block num devices.
This makes btrfs to reject the fs completely.
BTRFS error (device sdd3): super_num_devices 3 mismatch with num_devices 2 found here
BTRFS error (device sdd3): failed to read chunk tree: -22
BTRFS error (device sdd3): open_ctree failed
[CAUSE]
During btrfs device removal, chunk tree and super block num devs are
updated in two different transactions:
btrfs_rm_device()
|- btrfs_rm_dev_item(device)
| |- trans = btrfs_start_transaction()
| | Now we got transaction X
| |
| |- btrfs_del_item()
| | Now device item is removed from chunk tree
| |
| |- btrfs_commit_transaction()
| Transaction X got committed, super num devs untouched,
| but device item removed from chunk tree.
| (AKA, super num devs is already incorrect)
|
|- cur_devices->num_devices--;
|- cur_devices->total_devices--;
|- btrfs_set_super_num_devices()
All those operations are not in transaction X, thus it will
only be written back to disk in next transaction.
So after the transaction X in btrfs_rm_dev_item() committed, but before
transaction X+1 (which can be minutes away), a power loss happen, then
we got the super num mismatch.
This has been fixed by commit bbac58698a ("btrfs: remove device item
and update super block in the same transaction").
[FIX]
Make the super_num_devices check less strict, converting it from a hard
error to a warning, and reset the value to a correct one for the current
or next transaction commit.
As the number of device items is the critical information where the
super block num_devices is only a cached value (and also useful for
cross checking), it's safe to automatically update it. Other device
related problems like missing device are handled after that and may
require other means to resolve, like degraded mount. With this fix,
potentially affected filesystems won't fail mount and require the manual
repair by btrfs check.
Reported-by: Luca Béla Palkovics <luca.bela.palkovics@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/CA+8xDSpvdm_U0QLBAnrH=zqDq_cWCOH5TiV46CKmp3igr44okQ@mail.gmail.com/
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Parameter struct compressed_bio is not used by the function
submit_compressed_bio(). Remove it.
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When doing a NOCOW write, either through direct IO or buffered IO, we do
two lookups for the block group that contains the target extent: once
when we call btrfs_inc_nocow_writers() and then later again when we call
btrfs_dec_nocow_writers() after creating the ordered extent.
The lookups require taking a lock and navigating the red black tree used
to track all block groups, which can take a non-negligible amount of time
for a large filesystem with thousands of block groups, as well as lock
contention and cache line bouncing.
Improve on this by having a single block group search: making
btrfs_inc_nocow_writers() return the block group to its caller and then
have the caller pass that block group to btrfs_dec_nocow_writers().
This is part of a patchset comprised of the following patches:
btrfs: remove search start argument from first_logical_byte()
btrfs: use rbtree with leftmost node cached for tracking lowest block group
btrfs: use a read/write lock for protecting the block groups tree
btrfs: return block group directly at btrfs_next_block_group()
btrfs: avoid double search for block group during NOCOW writes
The following test was used to test these changes from a performance
perspective:
$ cat test.sh
#!/bin/bash
modprobe null_blk nr_devices=0
NULL_DEV_PATH=/sys/kernel/config/nullb/nullb0
mkdir $NULL_DEV_PATH
if [ $? -ne 0 ]; then
echo "Failed to create nullb0 directory."
exit 1
fi
echo 2 > $NULL_DEV_PATH/submit_queues
echo 16384 > $NULL_DEV_PATH/size # 16G
echo 1 > $NULL_DEV_PATH/memory_backed
echo 1 > $NULL_DEV_PATH/power
DEV=/dev/nullb0
MNT=/mnt/nullb0
LOOP_MNT="$MNT/loop"
MOUNT_OPTIONS="-o ssd -o nodatacow"
MKFS_OPTIONS="-R free-space-tree -O no-holes"
cat <<EOF > /tmp/fio-job.ini
[io_uring_writes]
rw=randwrite
fsync=0
fallocate=posix
group_reporting=1
direct=1
ioengine=io_uring
iodepth=64
bs=64k
filesize=1g
runtime=300
time_based
directory=$LOOP_MNT
numjobs=8
thread
EOF
echo performance | \
tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
echo
echo "Using config:"
echo
cat /tmp/fio-job.ini
echo
umount $MNT &> /dev/null
mkfs.btrfs -f $MKFS_OPTIONS $DEV &> /dev/null
mount $MOUNT_OPTIONS $DEV $MNT
mkdir $LOOP_MNT
truncate -s 4T $MNT/loopfile
mkfs.btrfs -f $MKFS_OPTIONS $MNT/loopfile &> /dev/null
mount $MOUNT_OPTIONS $MNT/loopfile $LOOP_MNT
# Trigger the allocation of about 3500 data block groups, without
# actually consuming space on underlying filesystem, just to make
# the tree of block group large.
fallocate -l 3500G $LOOP_MNT/filler
fio /tmp/fio-job.ini
umount $LOOP_MNT
umount $MNT
echo 0 > $NULL_DEV_PATH/power
rmdir $NULL_DEV_PATH
The test was run on a non-debug kernel (Debian's default kernel config),
the result were the following.
Before patchset:
WRITE: bw=1455MiB/s (1526MB/s), 1455MiB/s-1455MiB/s (1526MB/s-1526MB/s), io=426GiB (458GB), run=300006-300006msec
After patchset:
WRITE: bw=1503MiB/s (1577MB/s), 1503MiB/s-1503MiB/s (1577MB/s-1577MB/s), io=440GiB (473GB), run=300006-300006msec
+3.3% write throughput and +3.3% IO done in the same time period.
The test has somewhat limited coverage scope, as with only NOCOW writes
we get less contention on the red black tree of block groups, since we
don't have the extra contention caused by COW writes, namely when
allocating data extents, pinning and unpinning data extents, but on the
hand there's access to tree in the NOCOW path, when incrementing a block
group's number of NOCOW writers.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
At btrfs_next_block_group(), we have this long line with two statements:
cache = btrfs_lookup_first_block_group(...); return cache;
This makes it a bit harder to read due to two statements on the same
line, so change that to directly return the result of the call to
btrfs_lookup_first_block_group().
Reviewed-by: Nikolay Borisov <nborisov@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>
Currently we use a spin lock to protect the red black tree that we use to
track block groups. Most accesses to that tree are actually read only and
for large filesystems, with thousands of block groups, it actually has
a bad impact on performance, as concurrent read only searches on the tree
are serialized.
Read only searches on the tree are very frequent and done when:
1) Pinning and unpinning extents, as we need to lookup the respective
block group from the tree;
2) Freeing the last reference of a tree block, regardless if we pin the
underlying extent or add it back to free space cache/tree;
3) During NOCOW writes, both buffered IO and direct IO, we need to check
if the block group that contains an extent is read only or not and to
increment the number of NOCOW writers in the block group. For those
operations we need to search for the block group in the tree.
Similarly, after creating the ordered extent for the NOCOW write, we
need to decrement the number of NOCOW writers from the same block
group, which requires searching for it in the tree;
4) Decreasing the number of extent reservations in a block group;
5) When allocating extents and freeing reserved extents;
6) Adding and removing free space to the free space tree;
7) When releasing delalloc bytes during ordered extent completion;
8) When relocating a block group;
9) During fitrim, to iterate over the block groups;
10) etc;
Write accesses to the tree, to add or remove block groups, are much less
frequent as they happen only when allocating a new block group or when
deleting a block group.
We also use the same spin lock to protect the list of currently caching
block groups. Additions to this list are made when we need to cache a
block group, because we don't have a free space cache for it (or we have
but it's invalid), and removals from this list are done when caching of
the block group's free space finishes. These cases are also not very
common, but when they happen, they happen only once when the filesystem
is mounted.
So switch the lock that protects the tree of block groups from a spinning
lock to a read/write lock.
Reviewed-by: Nikolay Borisov <nborisov@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>
We keep track of the start offset of the block group with the lowest start
offset at fs_info->first_logical_byte. This requires explicitly updating
that field every time we add, delete or lookup a block group to/from the
red black tree at fs_info->block_group_cache_tree.
Since the block group with the lowest start address happens to always be
the one that is the leftmost node of the tree, we can use a red black tree
that caches the left most node. Then when we need the start address of
that block group, we can just quickly get the leftmost node in the tree
and extract the start offset of that node's block group. This avoids the
need to explicitly keep track of that address in the dedicated member
fs_info->first_logical_byte, and it also allows the next patch in the
series to switch the lock that protects the red black tree from a spin
lock to a read/write lock - without this change it would be tricky
because block group searches also update fs_info->first_logical_byte.
Reviewed-by: Nikolay Borisov <nborisov@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 search start argument passed to first_logical_byte() is always 0, as
we always want to get the logical start address of the block group with
the lowest logical start address. So remove it, as not only it is not
necessary, it also makes the following patches that change the lock that
protects the red black tree of block groups from a spin lock to a
read/write lock.
Reviewed-by: Nikolay Borisov <nborisov@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>
[BUG]
If we hit an error from submit_extent_page() inside
__extent_writepage_io(), we could still return 0 to the caller, and
even trigger the warning in btrfs_page_assert_not_dirty().
[CAUSE]
In __extent_writepage_io(), if we hit an error from
submit_extent_page(), we will just clean up the range and continue.
This is completely fine for regular PAGE_SIZE == sectorsize, as we can
only hit one sector in one page, thus after the error we're ensured to
exit and @ret will be saved.
But for subpage case, we may have other dirty subpage range in the page,
and in the next loop, we may succeeded submitting the next range.
In that case, @ret will be overwritten, and we return 0 to the caller,
while we have hit some error.
[FIX]
Introduce @has_error and @saved_ret to record the first error we hit, so
we will never forget what error we hit.
CC: stable@vger.kernel.org # 5.15+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
Test case generic/475 have a very high chance (almost 100%) to hit a fs
hang, where a data page will never be unlocked and hang all later
operations.
[CAUSE]
In btrfs_do_readpage(), if we hit an error from submit_extent_page() we
will try to do the cleanup for our current io range, and exit.
This works fine for PAGE_SIZE == sectorsize cases, but not for subpage.
For subpage btrfs_do_readpage() will lock the full page first, which can
contain several different sectors and extents:
btrfs_do_readpage()
|- begin_page_read()
| |- btrfs_subpage_start_reader();
| Now the page will have PAGE_SIZE / sectorsize reader pending,
| and the page is locked.
|
|- end_page_read() for different branches
| This function will reduce subpage readers, and when readers
| reach 0, it will unlock the page.
But when submit_extent_page() failed, we only cleanup the current
io range, while the remaining io range will never be cleaned up, and the
page remains locked forever.
[FIX]
Update the error handling of submit_extent_page() to cleanup all the
remaining subpage range before exiting the loop.
Please note that, now submit_extent_page() can only fail due to
sanity check in alloc_new_bio().
Thus regular IO errors are impossible to trigger the error path.
CC: stable@vger.kernel.org # 5.15+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
When running generic/475 with 64K page size and 4K sector size, it has a
very high chance (almost 100%) to hang, with mostly data page locked but
no one is going to unlock it.
[CAUSE]
With commit 1784b7d502 ("btrfs: handle csum lookup errors properly on
reads"), if we failed to lookup checksum due to metadata IO error, we
will return error for btrfs_submit_data_bio().
This will cause the page to be unlocked twice in btrfs_do_readpage():
btrfs_do_readpage()
|- submit_extent_page()
| |- submit_one_bio()
| |- btrfs_submit_data_bio()
| |- if (ret) {
| |- bio->bi_status = ret;
| |- bio_endio(bio); }
| In the endio function, we will call end_page_read()
| and unlock_extent() to cleanup the subpage range.
|
|- if (ret) {
|- unlock_extent(); end_page_read() }
Here we unlock the extent and cleanup the subpage range
again.
For unlock_extent(), it's mostly double unlock safe.
But for end_page_read(), it's not, especially for subpage case,
as for subpage case we will call btrfs_subpage_end_reader() to reduce
the reader number, and use that to number to determine if we need to
unlock the full page.
If double accounted, it can underflow the number and leave the page
locked without anyone to unlock it.
[FIX]
The commit 1784b7d502 ("btrfs: handle csum lookup errors properly on
reads") itself is completely fine, it's our existing code not properly
handling the error from bio submission hook properly.
This patch will make submit_one_bio() to return void so that the callers
will never be able to do cleanup when bio submission hook fails.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is an optimization for fix fee13fe965 ("btrfs: correct zstd
workspace manager lock to use spin_lock_bh()")
The critical region for wsm.lock is only accessed by the process context and
the softirq context.
Because in the soft interrupt, the critical section will not be
preempted by the soft interrupt again, there is no need to call
spin_lock_bh(&wsm.lock) to turn off the soft interrupt,
spin_lock(&wsm.lock) is enough for this situation.
Signed-off-by: Schspa Shi <schspa@gmail.com>
[ minor comment update ]
Signed-off-by: David Sterba <dsterba@suse.com>
We are still using the magic value of 2 at btrfs_create_new_inode(), but
there's now a constant for that, named BTRFS_DIR_START_INDEX, which was
introduced in commit 528ee69712 ("btrfs: put initial index value of a
directory in a constant"). So change that to use the constant.
Reviewed-by: Nikolay Borisov <nborisov@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>
