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For P/Q stripe scrub, we have quite some duplicated read IO:
- Data stripes read for verification
This is triggered by the scrub_submit_initial_read() inside
scrub_raid56_parity_stripe().
- Data stripes read (again) for P/Q stripe verification
This is triggered by scrub_assemble_read_bios() from scrub_rbio().
Although we can have hit rbio cache and avoid unnecessary read, the
chance is very low, as scrub would easily flush the whole rbio cache.
This means, even we're just scrubbing a single P/Q stripe, we would read
the data stripes twice for the best case scenario. If we need to
recover some data stripes, it would cause more reads on the same data
stripes, again and again.
However before we call raid56_parity_submit_scrub_rbio() we already
have all data stripes repaired and their contents ready to use.
But RAID56 cache is unaware about the scrub cache, thus RAID56 layer
itself still needs to re-read the data stripes.
To avoid such cache miss, this patch would:
- Introduce a new helper, raid56_parity_cache_data_pages()
This function would grab the pages from an array, and copy the content
to the rbio, marking all the involved sectors uptodate.
The page copy is unavoidable because of the cache pages of rbio are all
self managed, thus can not utilize outside pages without screwing up
the lifespan.
- Use the repaired data stripes as cache inside
scrub_raid56_parity_stripe()
By this, we ensure all the data sectors of the scrub rbio are already
uptodate, and no need to read them again from disk.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Using SECTOR_SHIFT to convert LBA to physical address makes it more
readable.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Use SECTOR_SHIFT while converting a physical address to an LBA, makes
it more readable.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Since the scrub rework, the following RAID56 functions are no longer
called:
- raid56_add_scrub_pages()
- raid56_alloc_missing_rbio()
- raid56_submit_missing_rbio()
Those functions are all utilized by scrub to handle missing device cases
for RAID56.
However the new scrub code handle them in a completely different way:
- If it's data stripe, go recovery path through btrfs_submit_bio()
- If it's P/Q stripe, it would be handled through
raid56_parity_submit_scrub_rbio()
And that function would handle dev-replace and repair properly.
Thus we can safely remove those functions.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The new helper will search the extent tree to find the first extent of a
logical range, then fill the sectors array by two loops:
- Loop 1 to fill common bits and metadata generation
- Loop 2 to fill csum data (only for data bgs)
This loop will use the new btrfs_lookup_csums_bitmap() to fill
the full csum buffer, and set scrub_sector_verification::csum.
With all the needed info filled by this function, later we only need to
submit and verify the stripe.
Here we temporarily export the helper to avoid warning on unused static
function.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The btrfs raid56 sector submission code uses bio_add_page() to add a
page to a newly created bio. bio_add_page() can fail, but the return
value is never checked.
Use __bio_add_page() as adding a single page to a newly created bio is
guaranteed to succeed.
This brings us a step closer to marking bio_add_page() as __must_check.
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.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>
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In btrfs_io_context structure, we have a pointer raid_map, which
indicates the logical bytenr for each stripe.
But considering we always call sort_parity_stripes(), the result
raid_map[] is always sorted, thus raid_map[0] is always the logical
bytenr of the full stripe.
So why we waste the space and time (for sorting) for raid_map?
This patch will replace btrfs_io_context::raid_map with a single u64
number, full_stripe_start, by:
- Replace btrfs_io_context::raid_map with full_stripe_start
- Replace call sites using raid_map[0] to use full_stripe_start
- Replace call sites using raid_map[i] to compare with nr_data_stripes.
The benefits are:
- Less memory wasted on raid_map
It's sizeof(u64) * num_stripes vs sizeof(u64).
It'll always save at least one u64, and the benefit grows larger with
num_stripes.
- No more weird alloc_btrfs_io_context() behavior
As there is only one fixed size + one variable length array.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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For btrfs dev-replace, we have to duplicate writes to the source
device into the target device.
For non-RAID56, all writes into the same mapped ranges are sharing the
same content, thus they don't really need to bother anything.
(E.g. in btrfs_submit_bio() for non-RAID56 range we just submit the
same write to all involved devices).
But for RAID56, all stripes contain different content, thus we must
have a clear mapping of which stripe is duplicated from which original
stripe.
Currently we use a complex way using tgtdev_map[] array, e.g:
num_tgtdevs = 1
tgtdev_map[0] = 0 <- Means stripes[0] is not involved in replace.
tgtdev_map[1] = 3 <- Means stripes[1] is involved in replace,
and it's duplicated to stripes[3].
tgtdev_map[2] = 0 <- Means stripes[2] is not involved in replace.
But this is wasting some space, and ignores one important thing for
dev-replace, there is at most one running replace.
Thus we can change it to a fixed array to represent the mapping:
replace_nr_stripes = 1
replace_stripe_src = 1 <- Means stripes[1] is involved in replace.
thus the extra stripe is a copy of
stripes[1]
By this we can save some space for bioc on RAID56 chunks with many
devices. And we get rid of one variable sized array from bioc.
Thus the patch involves the following changes:
- Replace @num_tgtdevs and @tgtdev_map[] with @replace_nr_stripes
and @replace_stripe_src.
@num_tgtdevs is just renamed to @replace_nr_stripes.
While the mapping is completely changed.
- Add extra ASSERT()s for RAID56 code
- Only add two more extra stripes for dev-replace cases.
As we have an upper limit on how many dev-replace stripes we can have.
- Unify the behavior of handle_ops_on_dev_replace()
Previously handle_ops_on_dev_replace() go two different paths for
WRITE and GET_READ_MIRRORS.
Now unify them by always going the WRITE path first (with at most 2
replace stripes), then if we're doing GET_READ_MIRRORS and we have 2
extra stripes, just drop one stripe.
- Remove the @real_stripes argument from alloc_btrfs_io_context()
As we don't need the old variable length array any more.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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These days all the operations that take locks in the raid56.c code are
run from user context (mostly workqueues). Drop all the irqsafe locking
that is not required any more.
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>
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The only caller of scrub_rbio calls rbio_orig_end_io right after it,
move it into scrub_rbio to match the other work item helpers.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Both callers of recover_rbio call rbio_orig_end_io right after it, so
move the call into the shared function.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Both callers of rmv_rbio call rbio_orig_end_io right after it, so
move the call into the shared function.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Instead of filling in a bio_list and submitting the bios in the only
caller, do that in scrub_assemble_read_bios. This removes the
need to pass the bio_list, and also makes it clear that the extra
bio_list cleanup in the caller is entirely pointless. Rename the
function to scrub_read_bios to make it clear that the bios are not
only assembled.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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There is very little extra code in rmw_read_bios, and a large part of it
is the superfluous extra cleanup of the bio list. Merge the two
functions, and only clean up the bio list after it has been added to
but before it has been emptied again by submit_read_wait_bio_list.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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There is very little extra code in recover_rbio, and a large part of it
is the superfluous extra cleanup of the bio list. Merge the two
functions, and only clean up the bio list after it has been added to
but before it has been emptied again by submit_read_wait_bio_list.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Add a helper to put all bios in a list. This does not need to be added
to block layer as there are no other users of such code.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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In addition to setting up the end_io handler and submitting the bios in
submit_read_bios, also wait for them to be completed instead of waiting
for the completion manually in all three callers.
Rename submit_read_bios to submit_read_wait_bio_list to make it clear
it waits for the bios as well.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Remove the write goto label by moving the data page allocation and data
read into the branch.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Handle the error return on alloc_rbio failure directly instead of using
a goto and remove the queue_rbio goto label by moving the plugged
check into the if branch.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.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>
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In rbio_update_error_bitmap(), we need to calculate the length of the
rbio. As since it's called in the endio function, we can not directly
grab the length from bi_iter.
Currently we call bio_for_each_segment_all(), which will always return a
range inside a page. But that's not necessary as we don't really care
about anything inside the page.
So use bio_for_each_bvec_all(), which can return a bvec across multiple
continuous pages thus reduce the loops.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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There quite a few spelling mistakes as found using codespell. Fix them.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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In the rework of raid56 code, there is very limited concurrency in the
endio context.
Most of the work is done inside the sectors arrays, which different bios
will never touch the same sector.
But there is a concurrency here for error_bitmap. Both read and write
endio functions need to touch them, and we can have multiple write bios
touching the same error bitmap if they all hit some errors.
Here we fix the unprotected bitmap operation by going set_bit() in a
loop.
Since we have a very small ceiling of the sectors (at most 16 sectors),
such set_bit() in a loop should be very acceptable.
Fixes: 2942a50dea74 ("btrfs: raid56: introduce btrfs_raid_bio::error_bitmap")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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We take two stripe numbers if vertical errors are found. In case it is
just a pstripe it does not matter but in case of raid 6 it matters as
both stripes need to be fixed.
Fixes: 7a3150723061 ("btrfs: raid56: do data csum verification during RMW cycle")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Tanmay Bhushan <007047221b@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Commit 75b470332965 ("btrfs: raid56: migrate recovery and scrub recovery
path to use error_bitmap") introduced an uninitialized return variable.
This can be caught by gcc 12.1 by -Wmaybe-uninitialized:
CC [M] fs/btrfs/raid56.o
fs/btrfs/raid56.c: In function ‘scrub_rbio’:
fs/btrfs/raid56.c:2801:15: warning: ‘ret’ may be used uninitialized [-Wmaybe-uninitialized]
2801 | ret = recover_scrub_rbio(rbio);
| ^~~~~~~~~~~~~~~~~~~~~~~~
fs/btrfs/raid56.c:2649:13: note: ‘ret’ was declared here
2649 | int ret;
The warning is disabled by default so we haven't caught that.
Due to the bug the raid56 scrub fstests have been failing since the
patch was merged, so initialize that.
Fixes: 75b470332965 ("btrfs: raid56: migrate recovery and scrub recovery path to use error_bitmap")
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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[BUG]
For the following small script, btrfs will be unable to recover the
content of file1:
mkfs.btrfs -f -m raid1 -d raid5 -b 1G $dev1 $dev2 $dev3
mount $dev1 $mnt
xfs_io -f -c "pwrite -S 0xff 0 64k" -c sync $mnt/file1
md5sum $mnt/file1
umount $mnt
# Corrupt the above 64K data stripe.
xfs_io -f -c "pwrite -S 0x00 323026944 64K" -c sync $dev3
mount $dev1 $mnt
# Write a new 64K, which should be in the other data stripe
# And this is a sub-stripe write, which will cause RMW
xfs_io -f -c "pwrite 0 64k" -c sync $mnt/file2
md5sum $mnt/file1
umount $mnt
Above md5sum would fail.
[CAUSE]
There is a long existing problem for raid56 (not limited to btrfs
raid56) that, if we already have some corrupted on-disk data, and then
trigger a sub-stripe write (which needs RMW cycle), it can cause further
damage into P/Q stripe.
Disk 1: data 1 |0x000000000000| <- Corrupted
Disk 2: data 2 |0x000000000000|
Disk 2: parity |0xffffffffffff|
In above case, data 1 is already corrupted, the original data should be
64KiB of 0xff.
At this stage, if we read data 1, and it has data checksum, we can still
recovery going via the regular RAID56 recovery path.
But if now we decide to write some data into data 2, then we need to go
RMW.
Let's say we want to write 64KiB of '0x00' into data 2, then we read the
on-disk data of data 1, calculate the new parity, resulting the
following layout:
Disk 1: data 1 |0x000000000000| <- Corrupted
Disk 2: data 2 |0x000000000000| <- New '0x00' writes
Disk 2: parity |0x000000000000| <- New Parity.
But the new parity is calculated using the *corrupted* data 1, we can
no longer recover the correct data of data1. Thus the corruption is
forever there.
[FIX]
To solve above problem, this patch will do a full stripe data checksum
verification at RMW time.
This involves the following changes:
- Always read the full stripe (including data/P/Q) when doing RMW
Before we only read the missing data sectors, but since we may do a
data csum verification and recovery, we need to read everything out.
Please note that, if we have a cached rbio, we don't need to read
anything, and can treat it the same as full stripe write.
As only stripe with all its csum matches can be cached.
- Verify the data csum during read.
The goal is only the rbio stripe sectors, and only if the rbio
already has csum_buf/csum_bitmap filled.
And sectors which cannot pass csum verification will have their bit
set in error_bitmap.
- Always call recovery_sectors() after we read out all the sectors
Since error_bitmap will be updated during read, recover_sectors()
can easily find out all the bad sectors and try to recover (if still
under tolerance).
And since recovery_sectors() is already migrated to use error_bitmap,
it can skip vertical stripes which don't have any error.
- Verify the repaired sectors against its csum in recover_vertical()
- Rename rmw_read_and_wait() to rmw_read_wait_recover()
Since we will always recover the sectors, the old name is no longer
accurate.
Furthermore since recovery is already done in rmw_read_wait_recover(),
we no longer need to call recovery_sectors() inside rmw_rbio().
Obviously this will have a performance impact, as we are doing more
work during RMW cycle:
- Fetch the data checksums
- Do checksum verification for all data stripes
- Do checksum verification again after repair
But for full stripe write or cached rbio we won't have the overhead all,
thus for fully optimized RAID56 workload (always full stripe write),
there should be no extra overhead.
To me, the extra overhead looks reasonable, as data consistency is way
more important than performance.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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This is for later data checksum verification at RMW time.
This patch will try to allocate the needed memory for a locked rbio if
the rbio is for data exclusively (we don't want to handle mixed bg yet).
The memory will be released when the rbio is finished.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Since all the recovery paths have been migrated to the new error bitmap
based system, we can remove the old stripe number based system.
This cleanup involves one behavior change:
- Rebuild rbio can no longer be merged
Previously a rebuild rbio (caused by retry after data csum mismatch)
can be merged, if the error happens in the same stripe.
But with the new error bitmap based solution, it's much harder to
compare error bitmaps.
So here we just don't merge rebuild rbio at all.
This may introduce some performance impact at extreme corner cases,
but we're willing to take it.
Other than that, this patch will cleanup the following members:
- rbio::faila
- rbio::failb
They will be replaced by per-vertical stripe check, which is more
accurate.
- rbio::error
It will be replace by per-vertical stripe error bitmap check.
- Allow get_rbio_vertical_errors() to accept NULL pointers for
@faila and @failb
Some call sites only want to check if we have errors beyond the
tolerance.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Since we have rbio::error_bitmap to indicate exactly where the errors
are (including read error and csum mismatch error), we can make recovery
path more accurate.
For example:
0 32K 64K
Data 1 |XXXXXXXX| |
Data 2 | |XXXXXXXXX|
Parity | | |
1) Get csum mismatch when reading data 1 [0, 32K)
2) Mark corresponding range error
The old code will mark the whole data 1 stripe as error.
While the new code will only mark data 1 [0, 32K) as error.
3) Recovery path
The old code will recover data 1 [0, 64K), all using Data 2 and
parity.
This means, Data 1 [32K, 64K) will be corrupted data, as data 2
[32K, 64K) is already corrupted.
While the new code will only recover data 1 [0, 32K), as only
that range has error so far.
This new behavior can avoid populating rbio cache with incorrect data.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Currently btrfs raid56 uses btrfs_raid_bio::faila and failb to indicate
which stripe(s) had IO errors.
But that has some problems:
- If one sector failed csum check, the whole stripe where the corruption
is will be marked error.
This can reduce the chance we do recover, like this:
0 4K 8K
Data 1 |XX| |
Data 2 | |XX|
Parity | | |
In above case, 0~4K in data 1 should be recovered using data 2 and
parity, while 4K~8K in data 2 should be recovered using data 1 and
parity.
Currently if we trigger read on 0~4K of data 1, we will also recover
4K~8K of data 1 using corrupted data 2 and parity, causing wrong
result in rbio cache.
- Harder to expand for future M-N scheme
As we're limited to just faila/b, two corruptions.
- Harder to expand to handle extra csum errors
This can be problematic if we start to do csum verification.
This patch will introduce an extra @error_bitmap, where one bit
represents error that happened for that sector.
The choice to introduce a new error bitmap other than reusing
sector_ptr, is to avoid extra search between rbio::stripe_sectors[] and
rbio::bio_sectors[].
Since we can submit bio using sectors from both sectors, doing proper
search on both array will more complex.
Although the new bitmap will take extra memory, later we can remove
things like @error and faila/b to save some memory.
Currently the new error bitmap and failab mechanism coexists, the error
bitmap is only updated at endio time and recover entrance.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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This switch involves the following changes:
- Make finish_parity_scrub() only to submit the write bios
It will no longer call rbio_orig_end_io(), and now it will
return error.
- Add a new helper, recover_scrub_rbio(), to handle recovery
It's just doing extra scrub related checks, and then call
recover_sectors().
- Rename raid56_parity_scrub_stripe() to scrub_rbio()
- Rename scrub_parity_work() to scrub_rbio_work_locked()
To follow the existing naming scheme.
- Delete unused functions
Including:
* finish_rmw()
* raid_write_end_io()
* raid56_bio_end_io()
* __raid_recover_end_io()
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Just like what we did for write/recovery, also extract the read bio
assembly code into a helper for scrub.
The difference between the three are:
- rmw_assemble_read_bios() only submit reads for missing sectors
Thus it will skip cached sectors, but will also read sectors which
is not covered by any full stripe. (For cache usage)
- recover_assemble_read_bios() reads every sector which has not failed
- scrub_assemble_read_bios() has extra check for vertical stripes
It's mostly the same as rmw_assemble_read_bios(), but will skip
sectors which is not covered by a vertical stripe.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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This includes the following changes:
- Implement new raid_unplug() functions
Now we don't need a workqueue to run the plug, as all our
work is just queue rmw_rbio_work() call, which can be executed
without sleep.
- Implement a rmw_rbio_work_locked() helper
This is for unlock_stripe(), which is already holding the full stripe
lock.
- Remove all the old functions
This should already shows how complex the old functions are, as we
ended up removing the following functions:
* rmw_work()
* validate_rbio_for_rmw()
* raid56_rmw_end_io_work()
* raid56_rmw_stripe()
* full_stripe_write()
* partial_stripe_write()
* __raid56_parity_write()
* run_plug()
* unplug_work()
* btrfs_raid_unplug()
* rmw_work()
* __raid56_parity_recover()
* raid_recover_end_io_work()
- Unexport rmw_rbio()
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The new entrance will be called rmw_rbio(), it will have a streamlined
workflow by using submit-and-wait method.
Thus there will be no weird jumps between tons of functions, thus way
more reader friendly, and will make later expansion easier, as it's now
a straight workflow, the timing is way more clear.
Unfortunately we can not yet migrate the RMW path to use this new
entrance as we still need extra work to address the plug and
unlock_stripe() function.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The helper will be later used to refactor the rmw write path.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The helper will later be used to refactor the whole RMW path.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Currently btrfs uses end_io functions to jump between different stages
of recovery.
For example, we go the following different functions:
- raid56_bio_end_io()
This handles the read for all the sectors (except the missing device).
- __raid_recover_end_io()
This does the real work, it's called inside the delayed work function
raid_recover_end_io_work().
This one recovery path involves at least 3 different functions, which is
a big burden for readers.
This patch will change the behavior by:
- Introduce a unified recovery entrance, recover_rbio()
- Use submit-and-wait method
So the workflow is not interrupted by the endio function jump.
This doesn't bring performance change, but reduce the burden for
reviewers.
- Run the main function in the rmw_workers workqueue
Now raid56_parity_recover() only needs to setup the work, and
queue the work using start_async_work().
Now readers only need to do one function jump (start_async_work()) to
find out the main entrance of recovery path.
Furthermore, recover_rbio() function can easily be reused by other paths.
The old recovery path is still utilized by degraded write path.
It will be cleaned up when we have migrated the write path.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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This includes extra changes:
- The allocation for unmap_array[] and pointers[]
Now we allocate them in one go, and free them together.
- Remove @err
Use errno_to_blk_status(ret) instead.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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This new helper will be also utilized in the incoming refactor of
recovery path.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Currently finish_rmw() will update the P/Q stripes before submitting
the writes.
It's done behind a for(;;) loop, it's a little congested indent-wise, so
extract the code into a helper called generate_pq_vertical().
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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This refactor includes the following behavior change first:
- Don't error out if only P/Q is corrupted
The old code will directly error out if only P/Q is corrupted.
Although it is an logical error if we go into rebuild path with
only P/Q corrupted, there is no need to error out.
Just skip the rebuild and return the already good data.
Then comes the following refactor which shouldn't cause behavior
changes:
- Introduce a helper to do vertical stripe recovery
This not only reduce one indent level, but also paves the road for
later data checksum verification in RMW cycles.
- Sort rbio->faila/b before recovery
So we don't need to do the same swap every vertical stripe
- Replace a BUG_ON() with ASSERT()
Or checkpatch won't let me pass.
- Mark recovered sectors uptodate after the recover loop
- Do the cleanup for pointers unconditionally
We only need to initialize @pointers and @unmap_array to NULL, so
we can safely free them unconditionally.
- Mark the repaired sector uptodate in recover_vertical()
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Update, reformat or reword function comments. This also removes the kdoc
marker so we don't get reports when the function name is missing.
Changes made:
- remove kdoc markers
- reformat the brief description to be a proper sentence
- reword to imperative voice
- align parameter list
- fix typos
Signed-off-by: David Sterba <dsterba@suse.com>
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We have a bunch of printk helpers that are in ctree.h. These have
nothing to do with ctree.c, so move them into their own header.
Subsequent patches will cleanup the printk helpers.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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data sectors uptodate
For Btrfs RAID56, we have a caching system for btrfs raid bios (rbio).
We call cache_rbio_pages() to mark a qualified rbio ready for cache.
The timing happens at:
- finish_rmw()
At this timing, we have already read all necessary sectors, along with
the rbio sectors, we have covered all data stripes.
- __raid_recover_end_io()
At this timing, we have rebuild the rbio, thus all data sectors
involved (either from stripe or bio list) are uptodate now.
Thus at the timing of cache_rbio_pages(), we should have all data
sectors uptodate.
This patch will make it explicit that all data sectors are uptodate at
cache_rbio_pages() timing, mostly to prepare for the incoming
verification at RMW time.
This patch will add:
- Extra ASSERT()s in cache_rbio_pages()
This is to make sure all data sectors, which are not covered by bio,
are already uptodate.
- Extra ASSERT()s in steal_rbio()
Since only cached rbio can be stolen, thus every data sector should
already be uptodate in the source rbio.
- Update __raid_recover_end_io() to update recovered sector->uptodate
Previously __raid_recover_end_io() will only mark failed sectors
uptodate if it's doing an RMW.
But this can trigger new ASSERT()s, as for recovery case, a recovered
failed sector will not be marked uptodate, and trigger ASSERT() in
later cache_rbio_pages() call.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Currently inside alloc_rbio(), we allocate a larger memory to contain
the following members:
- struct btrfs_raid_rbio itself
- stripe_pages array
- bio_sectors array
- stripe_sectors array
- finish_pointers array
Then update rbio pointers to point the extra space after the rbio
structure itself.
Thus it introduced a complex CONSUME_ALLOC() macro to help the thing.
This is too hacky, and is going to make later pointers expansion harder.
This patch will change it to use regular kcalloc() for each pointer
inside btrfs_raid_bio, making the later expansion much easier.
And introduce a helper free_raid_bio_pointers() to free up all the
pointer members in btrfs_raid_bio, which will be used in both
free_raid_bio() and error path of alloc_rbio().
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The cleanup involves two things:
- Remove the "__" prefix
There is no naming confliction.
- Remove the forward declaration
There is no special function call involved.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Currently if full_stripe_write() failed to allocate the pages for
parity, it will call __free_raid_bio() first, then return -ENOMEM.
But some caller of full_stripe_write() will also call __free_raid_bio()
again, this would cause double freeing.
And it's not a logically sound either, normally we should either free
the memory at the same level where we allocated it, or let endio to
handle everything.
So this patch will solve the double freeing by make
raid56_parity_write() to handle the error and free the rbio.
Just like what we do in raid56_parity_recover().
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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In raid56_alloc_missing_rbio(), if we can not determine where the
missing device is inside the full stripe, we just BUG_ON().
This is not necessary especially the only caller inside scrub.c is
already properly checking the return value, and will treat it as a
memory allocation failure.
Fix the error handling by:
- Add an extra warning for the reason
Although personally speaking it may be better to be an ASSERT().
- Properly free the allocated rbio
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The parity raid write/recover functionality is currently not very well
abstracted from the bio submission and completion handling in volumes.c:
- the raid56 code directly completes the original btrfs_bio fed into
btrfs_submit_bio instead of dispatching back to volumes.c
- the raid56 code consumes the bioc and bio_counter references taken
by volumes.c, which also leads to special casing of the calls from
the scrub code into the raid56 code
To fix this up supply a bi_end_io handler that calls back into the
volumes.c machinery, which then puts the bioc, decrements the bio_counter
and completes the original bio, and updates the scrub code to also
take ownership of the bioc and bio_counter in all cases.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
"This brings some long awaited changes, the send protocol bump,
otherwise lots of small improvements and fixes. The main core part is
reworking bio handling, cleaning up the submission and endio and
improving error handling.
There are some changes outside of btrfs adding helpers or updating
API, listed at the end of the changelog.
Features:
- sysfs:
- export chunk size, in debug mode add tunable for setting its size
- show zoned among features (was only in debug mode)
- show commit stats (number, last/max/total duration)
- send protocol updated to 2
- new commands:
- ability write larger data chunks than 64K
- send raw compressed extents (uses the encoded data ioctls),
ie. no decompression on send side, no compression needed on
receive side if supported
- send 'otime' (inode creation time) among other timestamps
- send file attributes (a.k.a file flags and xflags)
- this is first version bump, backward compatibility on send and
receive side is provided
- there are still some known and wanted commands that will be
implemented in the near future, another version bump will be
needed, however we want to minimize that to avoid causing
usability issues
- print checksum type and implementation at mount time
- don't print some messages at mount (mentioned as people asked about
it), we want to print messages namely for new features so let's
make some space for that
- big metadata - this has been supported for a long time and is
not a feature that's worth mentioning
- skinny metadata - same reason, set by default by mkfs
Performance improvements:
- reduced amount of reserved metadata for delayed items
- when inserted items can be batched into one leaf
- when deleting batched directory index items
- when deleting delayed items used for deletion
- overall improved count of files/sec, decreased subvolume lock
contention
- metadata item access bounds checker micro-optimized, with a few
percent of improved runtime for metadata-heavy operations
- increase direct io limit for read to 256 sectors, improved
throughput by 3x on sample workload
Notable fixes:
- raid56
- reduce parity writes, skip sectors of stripe when there are no
data updates
- restore reading from on-disk data instead of using stripe cache,
this reduces chances to damage correct data due to RMW cycle
- refuse to replay log with unknown incompat read-only feature bit
set
- zoned
- fix page locking when COW fails in the middle of allocation
- improved tracking of active zones, ZNS drives may limit the
number and there are ENOSPC errors due to that limit and not
actual lack of space
- adjust maximum extent size for zone append so it does not cause
late ENOSPC due to underreservation
- mirror reading error messages show the mirror number
- don't fallback to buffered IO for NOWAIT direct IO writes, we don't
have the NOWAIT semantics for buffered io yet
- send, fix sending link commands for existing file paths when there
are deleted and created hardlinks for same files
- repair all mirrors for profiles with more than 1 copy (raid1c34)
- fix repair of compressed extents, unify where error detection and
repair happen
Core changes:
- bio completion cleanups
- don't double defer compression bios
- simplify endio workqueues
- add more data to btrfs_bio to avoid allocation for read requests
- rework bio error handling so it's same what block layer does,
the submission works and errors are consumed in endio
- when asynchronous bio offload fails fall back to synchronous
checksum calculation to avoid errors under writeback or memory
pressure
- new trace points
- raid56 events
- ordered extent operations
- super block log_root_transid deprecated (never used)
- mixed_backref and big_metadata sysfs feature files removed, they've
been default for sufficiently long time, there are no known users
and mixed_backref could be confused with mixed_groups
Non-btrfs changes, API updates:
- minor highmem API update to cover const arguments
- switch all kmap/kmap_atomic to kmap_local
- remove redundant flush_dcache_page()
- address_space_operations::writepage callback removed
- add bdev_max_segments() helper"
* tag 'for-5.20-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (163 commits)
btrfs: don't call btrfs_page_set_checked in finish_compressed_bio_read
btrfs: fix repair of compressed extents
btrfs: remove the start argument to check_data_csum and export
btrfs: pass a btrfs_bio to btrfs_repair_one_sector
btrfs: simplify the pending I/O counting in struct compressed_bio
btrfs: repair all known bad mirrors
btrfs: merge btrfs_dev_stat_print_on_error with its only caller
btrfs: join running log transaction when logging new name
btrfs: simplify error handling in btrfs_lookup_dentry
btrfs: send: always use the rbtree based inode ref management infrastructure
btrfs: send: fix sending link commands for existing file paths
btrfs: send: introduce recorded_ref_alloc and recorded_ref_free
btrfs: zoned: wait until zone is finished when allocation didn't progress
btrfs: zoned: write out partially allocated region
btrfs: zoned: activate necessary block group
btrfs: zoned: activate metadata block group on flush_space
btrfs: zoned: disable metadata overcommit for zoned
btrfs: zoned: introduce space_info->active_total_bytes
btrfs: zoned: finish least available block group on data bg allocation
btrfs: let can_allocate_chunk return error
...
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Transfer the bio counter reference acquired by btrfs_submit_bio to
raid56_parity_write and raid56_parity_recovery together with the bio
that the reference was acquired for instead of acquiring another
reference in those helpers and dropping the original one in
btrfs_submit_bio.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
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