Always consume the bio and call the end_io handler on error instead of
returning an error and letting the caller handle it. This matches
what the block layer submission does and avoids any confusion on who
needs to handle errors.
As this requires touching all the callers, rename the function to
btrfs_submit_bio, which describes the functionality much better.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
All reads bio that go through btrfs_map_bio need to be completed in
user context. And read I/Os are the most common and timing critical
in almost any file system workloads.
Embed a work_struct into struct btrfs_bio and use it to complete all
read bios submitted through btrfs_map, using the REQ_META flag to decide
which workqueue they are placed on.
This removes the need for a separate 128 byte allocation (typically
rounded up to 192 bytes by slab) for all reads with a size increase
of 24 bytes for struct btrfs_bio. Future patches will reorganize
struct btrfs_bio to make use of this extra space for writes as well.
(All sizes are based a on typical 64-bit non-debug build)
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
Compressed write bio completion is the only user of btrfs_bio_wq_end_io
for writes, and the use of btrfs_bio_wq_end_io is a little suboptimal
here as we only real need user context for the final completion of a
compressed_bio structure, and not every single bio completion.
Add a work_struct to struct compressed_bio instead and use that to call
finish_compressed_bio_write. This allows to remove all handling of
write bios in the btrfs_bio_wq_end_io infrastructure.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
Both memzero_page and memcpy_to_page already call flush_dcache_page so
we can remove the calls from btrfs code.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
Although we have several data csum verification code, we never have a
function really just to verify checksum for one sector.
Function check_data_csum() do extra work for error reporting, thus it
requires a lot of extra things like file offset, bio_offset etc.
Function btrfs_verify_data_csum() is even worse, it will utilize page
checked flag, which means it can not be utilized for direct IO pages.
Here we introduce a new helper, btrfs_check_sector_csum(), which really
only accept a sector in page, and expected checksum pointer.
We use this function to implement check_data_csum(), and export it for
incoming patch.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
[hch: keep passing the csum array as an arguments, as the callers want
to print it, rename per request]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Derive the compression type from extent map as opposed to the bio flags
passed. This makes it more precise and not reliant on function
parameters.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
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>
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>
Several functions currently populate an array of page pointers one
allocated page at a time. Factor out the common code so as to allow
improvements to all of the sites at once.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This restores the logic from commit 46bcff2bfc ("btrfs: fix compressed
write bio blkcg attribution") which added cgroup attribution to btrfs
writeback. It also adds back the REQ_CGROUP_PUNT flag for these ios.
Fixes: 9150724048 ("btrfs: determine stripe boundary at bio allocation time in btrfs_submit_compressed_write")
CC: stable@vger.kernel.org # 5.16+
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Signed-off-by: David Sterba <dsterba@suse.com>
I hit some weird panics while fixing up the error handling from
btrfs_lookup_bio_sums(). Turns out the compression path will complete
the bio we use if we set up any of the compression bios and then return
an error, and then btrfs_submit_data_bio() will also call bio_endio() on
the bio.
Fix this by making btrfs_submit_compressed_read() responsible for
calling bio_endio() on the bio if there are any errors. Currently it
was only doing it if we created the compression bios, otherwise it was
depending on btrfs_submit_data_bio() to do the right thing. This
creates the above problem, so fix up btrfs_submit_compressed_read() to
always call bio_endio() in case of an error, and then simply return from
btrfs_submit_data_bio() if we had to call
btrfs_submit_compressed_read().
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Right now we just have a binary "errors" flag, so any error we get on
the compressed bio's gets translated to EIO. This isn't necessarily a
bad thing, but if we get an ENOMEM it may be nice to know that's what
happened instead of an EIO. Track our errors as a blk_status_t, and do
the appropriate setting of the errors accordingly.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This bio is usually one of the compressed bio's, and we don't actually
need it in this function, so remove the argument and stop passing it
around.
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>
Commit c09abff87f ("btrfs: cloned bios must not be iterated by
bio_for_each_segment_all") added ASSERT()'s to make sure we weren't
calling bio_for_each_segment_all() on a RAID5/6 bio. However it was
checking the bio that the compression code passed in, not the
cb->orig_bio that we actually iterate over, so adjust this ASSERT() to
check the correct bio.
Reviewed-by: Boris Burkov <boris@bur.io>
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>
The implementation resembles direct I/O: we have to flush any ordered
extents, invalidate the page cache, and do the io tree/delalloc/extent
map/ordered extent dance. From there, we can reuse the compression code
with a minor modification to distinguish the write from writeback. This
also creates inline extents when possible.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_csum_one_bio() loops over each filesystem block in the bio while
keeping a cursor of its current logical position in the file in order to
look up the ordered extent to add the checksums to. However, this
doesn't make much sense for compressed extents, as a sector on disk does
not correspond to a sector of decompressed file data. It happens to work
because:
1) the compressed bio always covers one ordered extent
2) the size of the bio is always less than the size of the ordered
extent
However, the second point will not always be true for encoded writes.
Let's add a boolean parameter to btrfs_csum_one_bio() to indicate that
it can assume that the bio only covers one ordered extent. Since we're
already changing the signature, let's get rid of the contig parameter
and make it implied by the offset parameter, similar to the change we
recently made to btrfs_lookup_bio_sums(). Additionally, let's rename
nr_sectors to blockcount to make it clear that it's the number of
filesystem blocks, not the number of 512-byte sectors.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_decompress_bio, the only caller of compression_decompress_bio gets
type from @cb and passes it to compression_decompress_bio.
However, compression_decompress_bio can get compression type directly
from @cb.
So remove the parameter and access it through @cb. No functional
change.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Su Yue <l@damenly.su>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have a few places where we skip doing csums if we mounted with one of
the rescue options that ignores bad csum roots. In the future when
there are multiple csum roots it'll be costly to check and see if there
are any missing csum roots, so simply add a flag to indicate the fs
should skip loading csums in case of errors.
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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Merge tag 'for-5.16-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
"The updates this time are more under the hood and enhancing existing
features (subpage with compression and zoned namespaces).
Performance related:
- misc small inode logging improvements (+3% throughput, -11% latency
on sample dbench workload)
- more efficient directory logging: bulk item insertion, less tree
searches and locking
- speed up bulk insertion of items into a b-tree, which is used when
logging directories, when running delayed items for directories
(fsync and transaction commits) and when running the slow path
(full sync) of an fsync (bulk creation run time -4%, deletion -12%)
Core:
- continued subpage support
- make defragmentation work
- make compression write work
- zoned mode
- support ZNS (zoned namespaces), zone capacity is number of
usable blocks in each zone
- add dedicated block group (zoned) for relocation, to prevent
out of order writes in some cases
- greedy block group reclaim, pick the ones with least usable
space first
- preparatory work for send protocol updates
- error handling improvements
- cleanups and refactoring
Fixes:
- lockdep warnings
- in show_devname callback, on seeding device
- device delete on loop device due to conversions to workqueues
- fix deadlock between chunk allocation and chunk btree modifications
- fix tracking of missing device count and status"
* tag 'for-5.16-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (140 commits)
btrfs: remove root argument from check_item_in_log()
btrfs: remove root argument from add_link()
btrfs: remove root argument from btrfs_unlink_inode()
btrfs: remove root argument from drop_one_dir_item()
btrfs: clear MISSING device status bit in btrfs_close_one_device
btrfs: call btrfs_check_rw_degradable only if there is a missing device
btrfs: send: prepare for v2 protocol
btrfs: fix comment about sector sizes supported in 64K systems
btrfs: update device path inode time instead of bd_inode
fs: export an inode_update_time helper
btrfs: fix deadlock when defragging transparent huge pages
btrfs: sysfs: convert scnprintf and snprintf to sysfs_emit
btrfs: make btrfs_super_block size match BTRFS_SUPER_INFO_SIZE
btrfs: update comments for chunk allocation -ENOSPC cases
btrfs: fix deadlock between chunk allocation and chunk btree modifications
btrfs: zoned: use greedy gc for auto reclaim
btrfs: check-integrity: stop storing the block device name in btrfsic_dev_state
btrfs: use btrfs_get_dev_args_from_path in dev removal ioctls
btrfs: add a btrfs_get_dev_args_from_path helper
btrfs: handle device lookup with btrfs_dev_lookup_args
...
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Merge tag 'for-5.16/block-2021-10-29' of git://git.kernel.dk/linux-block
Pull block updates from Jens Axboe:
- mq-deadline accounting improvements (Bart)
- blk-wbt timer fix (Andrea)
- Untangle the block layer includes (Christoph)
- Rework the poll support to be bio based, which will enable adding
support for polling for bio based drivers (Christoph)
- Block layer core support for multi-actuator drives (Damien)
- blk-crypto improvements (Eric)
- Batched tag allocation support (me)
- Request completion batching support (me)
- Plugging improvements (me)
- Shared tag set improvements (John)
- Concurrent queue quiesce support (Ming)
- Cache bdev in ->private_data for block devices (Pavel)
- bdev dio improvements (Pavel)
- Block device invalidation and block size improvements (Xie)
- Various cleanups, fixes, and improvements (Christoph, Jackie,
Masahira, Tejun, Yu, Pavel, Zheng, me)
* tag 'for-5.16/block-2021-10-29' of git://git.kernel.dk/linux-block: (174 commits)
blk-mq-debugfs: Show active requests per queue for shared tags
block: improve readability of blk_mq_end_request_batch()
virtio-blk: Use blk_validate_block_size() to validate block size
loop: Use blk_validate_block_size() to validate block size
nbd: Use blk_validate_block_size() to validate block size
block: Add a helper to validate the block size
block: re-flow blk_mq_rq_ctx_init()
block: prefetch request to be initialized
block: pass in blk_mq_tags to blk_mq_rq_ctx_init()
block: add rq_flags to struct blk_mq_alloc_data
block: add async version of bio_set_polled
block: kill DIO_MULTI_BIO
block: kill unused polling bits in __blkdev_direct_IO()
block: avoid extra iter advance with async iocb
block: Add independent access ranges support
blk-mq: don't issue request directly in case that current is to be blocked
sbitmap: silence data race warning
blk-cgroup: synchronize blkg creation against policy deactivation
block: refactor bio_iov_bvec_set()
block: add single bio async direct IO helper
...
In end_compressed_writeback() we just clear the full page writeback.
For subpage case, if there are two delalloc ranges in the same page, the
2nd range will trigger a BUG_ON() as the page writeback is already
cleared by previous range.
Fix it by using btrfs_page_clamp_clear_writeback() helper.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is a WARN_ON() checking if @start is aligned to PAGE_SIZE, not
sectorsize, which will cause false alert for subpage. Fix it to check
against sectorsize.
Furthermore:
- Use ASSERT() to do the check
So that in the future we may skip the check for production build
- Also check alignment for @len
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently btrfs_submit_compressed_write() will check
btrfs_bio_fits_in_stripe() each time a new page is going to be added.
Even if compressed extent is small, we don't really need to do that for
every page.
Align the behavior to extent_io.c, by determining the stripe boundary
when allocating a bio.
Unlike extent_io.c, in compressed.c we don't need to bother things like
different bio flags, thus no need to re-use bio_ctrl.
Here we just manually introduce new local variable, next_stripe_start,
and use that value returned from alloc_compressed_bio() to calculate
the stripe boundary.
Then each time we add some page range into the bio, we check if we
reached the boundary. And if reached, submit it.
Also, since we have @cur_disk_bytenr to determine whether we're the last
bio, we don't need a explicit last_bio: tag for error handling any more.
And since we use @cur_disk_bytenr to wait, there is no need for
pending_bios, also remove it to save some memory of compressed_bio.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently btrfs_submit_compressed_read() will check
btrfs_bio_fits_in_stripe() each time a new page is going to be added.
Even if compressed extent is small, we don't really need to do that for
every page.
This patch will align the behavior to extent_io.c, by determining the
stripe boundary when allocating a bio.
Unlike extent_io.c, in compressed.c we don't need to bother things like
different bio flags, thus no need to re-use bio_ctrl.
Here we just manually introduce new local variable, next_stripe_start,
and teach alloc_compressed_bio() to calculate the stripe boundary.
Then each time we add some page range into the bio, we check if we
reached the boundary. And if reached, submit it.
Also, since we have @cur_disk_byte to determine whether we're the last
bio, we don't need a explicit last_bio: tag for error handling any more.
And we can use @cur_disk_byte to track which range has been added to
bio, we can also use @cur_disk_byte to calculate the wait condition, no
need for @pending_bios.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Just aggregate the bio allocation code into one helper, so that we can
replace 4 call sites.
There is one special note for zoned write.
Currently btrfs_submit_compressed_write() will only allocate the first
bio using ZONE_APPEND. If we have to submit current bio due to stripe
boundary, the new bio allocated will not use ZONE_APPEND.
In theory this should be a bug, but considering zoned mode currently
only support SINGLE profile, which doesn't have any stripe boundary
limit, it should never be a problem and we have assertions in place.
This function will provide a good entrance for any work which needs to
be done at bio allocation time. Like determining the stripe boundary.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The new helper, submit_compressed_bio(), will aggregate the following
work:
- Increase compressed_bio::pending_bios
- Remap the endio function
- Map and submit the bio
This slightly reorders calls to btrfs_csum_one_bio or
btrfs_lookup_bio_sums but but none of them does anything regarding IO
submission so this is effectively no change. We mainly care about order
of
- atomic_inc
- btrfs_bio_wq_end_io
- btrfs_map_bio
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Just like btrfs_submit_compressed_read(), there are quite some BUG_ON()s
inside btrfs_submit_compressed_write() for the bio submission path.
Fix them using the same method:
- For last bio, just endio the bio
As in that case, one of the endio function of all these submitted bio
will be able to free the compressed_bio
- For half-submitted bio, wait and finish the compressed_bio manually
In this case, as long as all other bio finish, we're the only one
referring the compressed bio, and can manually finish it.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are quite some BUG_ON()s inside btrfs_submit_compressed_read(),
namely all errors inside the for() loop relies on BUG_ON() to handle
-ENOMEM.
Handle these errors properly by:
- Wait for submitted bios to finish first
Using wake_var_event() APIs to wait without introducing extra memory
overhead inside compressed_bio.
This allows us to wait for any submitted bio to finish, while still
keeps the compressed_bio from being freed.
- Introduce finish_compressed_bio_read() to finish the compressed_bio
- Properly end the bio and finish compressed_bio when error happens
Now in btrfs_submit_compressed_read() even when the bio submission
failed, we can properly handle the error without triggering BUG_ON().
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Although in btrfs we have very limited usage of PageChecked flag, it's
still some page flag not yet subpage compatible.
Fix it by introducing btrfs_subpage::checked_offset to do the convert.
For most call sites, especially for free-space cache, COW fixup and
btrfs_invalidatepage(), they all work in full page mode anyway.
For other call sites, they work as subpage compatible mode.
Some call sites need extra modification:
- btrfs_drop_pages()
Needs extra parameter to get the real range we need to clear checked
flag.
Also since btrfs_drop_pages() will accept pages beyond the dirtied
range, update btrfs_subpage_clamp_range() to handle such case
by setting @len to 0 if the page is beyond target range.
- btrfs_invalidatepage()
We need to call subpage helper before calling __btrfs_releasepage(),
or it will trigger ASSERT() as page->private will be cleared.
- btrfs_verify_data_csum()
In theory we don't need the io_bio->csum check anymore, but it's
won't hurt. Just change the comment.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For btrfs_submit_compressed_read() and btrfs_submit_compressed_write(),
we have a pretty weird dance around compressed_bio::pending_bios:
btrfs_submit_compressed_read/write()
{
cb = kmalloc()
refcount_set(&cb->pending_bios, 0);
bio = btrfs_alloc_bio();
/* NOTE here, we haven't yet submitted any bio */
refcount_set(&cb->pending_bios, 1);
for (pg_index = 0; pg_index < cb->nr_pages; pg_index++) {
if (submit) {
/* Here we submit bio, but we always have one
* extra pending_bios */
refcount_inc(&cb->pending_bios);
ret = btrfs_map_bio();
}
}
/* Submit the last bio */
ret = btrfs_map_bio();
}
There are two reasons why we do this:
- compressed_bio::pending_bios is a refcount
Thus if it's reduced to 0, it can not be increased again.
- To ensure the compressed_bio is not freed by some submitted bios
If the submitted bio is finished before the next bio submitted,
we can free the compressed_bio completely.
But the above code is sometimes confusing, and we can do it better by
introducing a new member, compressed_bio::pending_sectors.
Now we use compressed_bio::pending_sectors to indicate whether we have
any pending sectors under IO or not yet submitted.
If pending_sectors == 0, we're definitely the last bio of compressed_bio,
and is OK to release the compressed bio.
Now the workflow looks like this:
btrfs_submit_compressed_read/write()
{
cb = kmalloc()
atomic_set(&cb->pending_bios, 0);
refcount_set(&cb->pending_sectors,
compressed_len >> sectorsize_bits);
bio = btrfs_alloc_bio();
for (pg_index = 0; pg_index < cb->nr_pages; pg_index++) {
if (submit) {
refcount_inc(&cb->pending_bios);
ret = btrfs_map_bio();
}
}
/* Submit the last bio */
refcount_inc(&cb->pending_bios);
ret = btrfs_map_bio();
}
For now we still need pending_bios for later error handling, but will
remove pending_bios eventually after properly handling the errors.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
If we remove the subpage limitation in add_ra_bio_pages(), then read a
compressed extent which has part of its range in next page, like the
following inode layout:
0 32K 64K 96K 128K
|<--------------|-------------->|
Btrfs will trigger ASSERT() in endio function:
assertion failed: atomic_read(&subpage->readers) >= nbits
------------[ cut here ]------------
kernel BUG at fs/btrfs/ctree.h:3431!
Internal error: Oops - BUG: 0 [#1] SMP
Workqueue: btrfs-endio btrfs_work_helper [btrfs]
Call trace:
assertfail.constprop.0+0x28/0x2c [btrfs]
btrfs_subpage_end_reader+0x148/0x14c [btrfs]
end_page_read+0x8c/0x100 [btrfs]
end_bio_extent_readpage+0x320/0x6b0 [btrfs]
bio_endio+0x15c/0x1dc
end_workqueue_fn+0x44/0x64 [btrfs]
btrfs_work_helper+0x74/0x250 [btrfs]
process_one_work+0x1d4/0x47c
worker_thread+0x180/0x400
kthread+0x11c/0x120
ret_from_fork+0x10/0x30
---[ end trace c8b7b552d3bb408c ]---
[CAUSE]
When we read the page range [0, 64K), we find it's a compressed extent,
and we will try to add extra pages in add_ra_bio_pages() to avoid
reading the same compressed extent.
But when we add such page into the read bio, it doesn't follow the
behavior of btrfs_do_readpage() to properly set subpage::readers.
This means, for page [64K, 128K), its subpage::readers is still 0.
And when endio is executed on both pages, since page [64K, 128K) has 0
subpage::readers, it triggers above ASSERT()
[FIX]
Function add_ra_bio_pages() is far from subpage compatible, it always
assume PAGE_SIZE == sectorsize, thus when it skip to next range it
always just skip PAGE_SIZE.
Make it subpage compatible by:
- Skip to next page properly when needed
If we find there is already a page cache, we need to skip to next page.
For that case, we shouldn't just skip PAGE_SIZE bytes, but use
@pg_index to calculate the next bytenr and continue.
- Only add the page range covered by current extent map
We need to calculate which range is covered by current extent map and
only add that part into the read bio.
- Update subpage::readers before submitting the bio
- Use proper cursor other than confusing @last_offset
- Calculate the missed threshold based on sector size
It's no longer using missed pages, as for 64K page size, we have at
most 3 pages to skip. (If aligned only 2 pages)
- Add ASSERT() to make sure our bytenr is always aligned
- Add comment for the function
Add a special note for subpage case, as the function won't really
work well for subpage cases.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Variable @nr_pages only gets increased but never used. Remove it.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Previously we had "struct btrfs_bio", which records IO context for
mirrored IO and RAID56, and "strcut btrfs_io_bio", which records extra
btrfs specific info for logical bytenr bio.
With "btrfs_bio" renamed to "btrfs_io_context", we are safe to rename
"btrfs_io_bio" to "btrfs_bio" which is a more suitable name now.
The struct btrfs_bio changes meaning by this commit. There was a
suggested name like btrfs_logical_bio but it's a bit long and we'd
prefer to use a shorter name.
This could be a concern for backports to older kernels where the
different meaning could possibly cause confusion or bugs. Comparing the
new and old structures, there's no overlap among the struct members so a
build would break in case of incorrect backport.
We haven't had many backports to bio code anyway so this is more of a
theoretical cause of bugs and a matter of precaution but we'll need to
keep the semantic change in mind.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The helper btrfs_bio_alloc() is almost the same as btrfs_io_bio_alloc(),
except it's allocating using BIO_MAX_VECS as @nr_iovecs, and initializes
bio->bi_iter.bi_sector.
However the naming itself is not using "btrfs_io_bio" to indicate its
parameter is "strcut btrfs_io_bio" and can be easily confused with
"struct btrfs_bio".
Considering assigned bio->bi_iter.bi_sector is such a simple work and
there are already tons of call sites doing that manually, there is no
need to do that in a helper.
Remove btrfs_bio_alloc() helper, and enhance btrfs_io_bio_alloc()
function to provide a fail-safe value for its @nr_iovecs.
And then replace all btrfs_bio_alloc() callers with
btrfs_io_bio_alloc().
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 no need to pull blk-cgroup.h and thus blkdev.h in here, so
break the include chain.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20210920123328.1399408-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There are several bugs inside the function btrfs_decompress_buf2page()
- @start_byte doesn't take bvec.bv_offset into consideration
Thus it can't handle case where the target range is not page aligned.
- Too many helper variables
There are tons of helper variables, @buf_offset, @current_buf_start,
@start_byte, @prev_start_byte, @working_bytes, @bytes.
This hurts anyone who wants to read the function.
- No obvious main cursor for the iteartion
A new problem caused by previous problem.
- Comments for parameter list makes no sense
Like @buf_start is the offset to @buf, or offset inside the full
decompressed extent? (Spoiler alert, the later case)
And @total_out acts more like @buf_start + @size_of_buf.
The worst is @disk_start.
The real meaning of it is the file offset of the full decompressed
extent.
This patch will rework the whole function by:
- Add a proper comment with ASCII art to explain the parameter list
- Rework parameter list
The old @buf_start is renamed to @decompressed, to show how many bytes
are already decompressed inside the full decompressed extent.
The old @total_out is replaced by @buf_len, which is the decompressed
data size.
For old @disk_start and @bio, just pass @compressed_bio in.
- Use single main cursor
The main cursor will be @cur_file_offset, to show what's the current
file offset.
Other helper variables will be declared inside the main loop, and only
minimal amount of helper variables:
* offset_inside_decompressed_buf: The only real helper
* copy_start_file_offset: File offset we start memcpy
* bvec_file_offset: File offset of current bvec
Even with all these extensive comments, the final function is still
smaller than the original function, which is definitely a win.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
When subpage compressed read write support is enabled, btrfs/038 always
fails with EIO.
A simplified script can easily trigger the problem:
mkfs.btrfs -f -s 4k $dev
mount $dev $mnt -o compress=lzo
xfs_io -f -c "truncate 118811" $mnt/foo
xfs_io -c "pwrite -S 0x0d -b 39987 92267 39987" $mnt/foo > /dev/null
sync
btrfs subvolume snapshot -r $mnt $mnt/mysnap1
xfs_io -c "pwrite -S 0x3e -b 80000 200000 80000" $mnt/foo > /dev/null
sync
xfs_io -c "pwrite -S 0xdc -b 10000 250000 10000" $mnt/foo > /dev/null
xfs_io -c "pwrite -S 0xff -b 10000 300000 10000" $mnt/foo > /dev/null
sync
btrfs subvolume snapshot -r $mnt $mnt/mysnap2
cat $mnt/mysnap2/foo
# Above cat will fail due to EIO
[CAUSE]
The problem is in btrfs_submit_compressed_read().
When it tries to grab the extent map of the read range, it uses the
following call:
em = lookup_extent_mapping(em_tree,
page_offset(bio_first_page_all(bio)),
fs_info->sectorsize);
The problem is in the page_offset(bio_first_page_all(bio)) part.
The offending inode has the following file extent layout
item 10 key (257 EXTENT_DATA 131072) itemoff 15639 itemsize 53
generation 8 type 1 (regular)
extent data disk byte 13680640 nr 4096
extent data offset 0 nr 4096 ram 4096
extent compression 0 (none)
item 11 key (257 EXTENT_DATA 135168) itemoff 15586 itemsize 53
generation 8 type 1 (regular)
extent data disk byte 0 nr 0
item 12 key (257 EXTENT_DATA 196608) itemoff 15533 itemsize 53
generation 8 type 1 (regular)
extent data disk byte 13676544 nr 4096
extent data offset 0 nr 53248 ram 86016
extent compression 2 (lzo)
And the bio passed in has the following parameters:
page_offset(bio_first_page_all(bio)) = 131072
bio_first_bvec_all(bio)->bv_offset = 65536
If we use page_offset(bio_first_page_all(bio) without adding bv_offset,
we will get an extent map for file offset 131072, not 196608.
This means we read uncompressed data from disk, and later decompression
will definitely fail.
[FIX]
Take bv_offset into consideration when trying to grab an extent map.
And add an ASSERT() to ensure we're really getting a compressed extent.
Thankfully this won't affect anything but subpage, thus we only need to
ensure this patch get merged before we enabled basic subpage support.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For current subpage support, we only support 64K page size with 4K
sector size.
This makes compressed readahead less effective, as maximum compressed
extent size is only 128K, 2x the page size.
On the other hand, the function add_ra_bio_pages() is still assuming
sectorsize == PAGE_SIZE, and code change may affect 4K page size
systems.
So for now, let's disable subpage compressed readahead for now.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The pages in compressed_pages are not from highmem anymore so we can
drop the mapping for checksum calculation and inline extent.
Signed-off-by: David Sterba <dsterba@suse.com>
The highmem flag is used for allocating pages for compression and for
raid56 pages. The high memory makes sense on 32bit systems but is not
without problems. On 64bit system's it's just another layer of wrappers.
The time the pages are allocated for compression or raid56 is relatively
short (about a transaction commit), so the pages are not blocked
indefinitely. As the number of pages depends on the amount of data being
written/read, there's a theoretical problem. A fast device on a 32bit
system could use most of the low memory pool, while with the highmem
allocation that would not happen. This was possibly the original idea
long time ago, but nowadays we optimize for 64bit systems.
This patch removes all usage of the __GFP_HIGHMEM flag for page
allocation, the kmap/kunmap are still in place and will be removed in
followup patches. Remaining is masking out the bit in
alloc_extent_state and __lookup_free_space_inode, that can safely stay.
Signed-off-by: David Sterba <dsterba@suse.com>
In compression write endio sequence, the range which the compressed_bio
writes is marked as uptodate if the last bio of the compressed (sub)bios
is completed successfully. There could be previous bio which may
have failed which is recorded in cb->errors.
Set the writeback range as uptodate only if cb->errors is zero, as opposed
to checking only the last bio's status.
Backporting notes: in all versions up to 4.4 the last argument is always
replaced by "!cb->errors".
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since commit 8140dc30a4 ("btrfs: btrfs_decompress_bio() could accept
compressed_bio instead"), btrfs_decompress_bio() accepts
"struct compressed_bio" other than open-coded parameter list.
Thus the comments for the parameter list is no longer needed.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
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 a pretty bad abuse of btrfs_writepage_endio_finish_ordered() in
end_compressed_bio_write().
It passes compressed pages to btrfs_writepage_endio_finish_ordered(),
which is only supposed to accept inode pages.
Thankfully the important info here is the inode, so let's pass
btrfs_inode directly into btrfs_writepage_endio_finish_ordered(), and
make @page parameter optional.
By this, end_compressed_bio_write() can happily pass page=NULL while
still getting everything done properly.
Also, to cooperate with such modification, replace @page parameter for
trace_btrfs_writepage_end_io_hook() with btrfs_inode.
Although this removes page_index info, the existing start/len should be
enough for most usage.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Commit e5d7490236 ("btrfs: derive maximum output size in the
compression implementation") removed @max_out argument in
btrfs_compress_pages() but its comment remained, remove it.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Patch "btrfs: reduce compressed_bio member's types" reduced some
member's size. Function arguments @len, @compressed_len and @nr_pages
can be declared as unsigned int.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Patch "btrfs: reduce compressed_bio member's types" reduced some
member's size. Declare the variables @compressed_len, @nr_pages and
@pg_index size as an unsigned int in the function
btrfs_submit_compressed_read.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Several members of compressed_bio are of type that's unnecessarily big
for the values that they'd hold:
- the size of the uncompressed and compressed data is 128K now, we can
keep is as int
- same for number of pages
- the compress type fits to a byte
- the errors is 0/1
The size of the unpatched structure is 80 bytes with several holes.
Reordering nr_pages next to the pages the hole after pending_bios is
filled and the resulting size is 56 bytes. This keeps the csums array
aligned to 8 bytes, which is nice. Further size optimizations may be
possible but right now it looks good to me:
struct compressed_bio {
refcount_t pending_bios; /* 0 4 */
unsigned int nr_pages; /* 4 4 */
struct page * * compressed_pages; /* 8 8 */
struct inode * inode; /* 16 8 */
u64 start; /* 24 8 */
unsigned int len; /* 32 4 */
unsigned int compressed_len; /* 36 4 */
u8 compress_type; /* 40 1 */
u8 errors; /* 41 1 */
/* XXX 2 bytes hole, try to pack */
int mirror_num; /* 44 4 */
struct bio * orig_bio; /* 48 8 */
u8 sums[]; /* 56 0 */
/* size: 56, cachelines: 1, members: 12 */
/* sum members: 54, holes: 1, sum holes: 2 */
/* last cacheline: 56 bytes */
};
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
To be able to construct a zone append bio we need to look up the
btrfs_device. The code doing the chunk map lookup to get the device is
present in btrfs_submit_compressed_write and submit_extent_page.
Factor out the lookup calls into a helper and use it in the submission
paths.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
