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Add a helper to complete an ordered_extent without first doing a lookup.
The tracepoint cannot use the ordered_extent class as we also want to
print the range.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.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 callers are gone now.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The btrfs zoned completion code currently needs an ordered_extent and
extent_map per bio so that it can account for the non-predictable
write location from Zone Append. To archive that it currently splits
the ordered_extent and extent_map at I/O submission time, and then
records the actual physical address in the ->physical field of the
ordered_extent.
This patch instead switches to record the "original" physical address
that the btrfs allocator assigned in spare space in the btrfs_bio,
and then rewrites the logical address in the btrfs_ordered_sum
structure at I/O completion time. This allows the ordered extent
completion handler to simply walk the list of ordered csums and
split the ordered extent as needed. This removes an extra ordered
extent and extent_map lookup and manipulation during the I/O
submission path, and instead batches it in the I/O completion path
where we need to touch these anyway.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
Return the ordered_extent split from the passed in one. This will be
needed to be able to store an ordered_extent in the btrfs_bio.
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.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>
The current code to store the final logical to physical mapping for a
zone append write in the extent tree is rather inefficient. It first has
to split the ordered extent so that there is one ordered extent per bio,
so that it can look up the ordered extent on I/O completion in
btrfs_record_physical_zoned and store the physical LBA returned by the
block driver in the ordered extent.
btrfs_rewrite_logical_zoned then has to do a lookup in the chunk tree to
see what physical address the logical address for this bio / ordered
extent is mapped to, and then rewrite it in the extent tree.
To optimize this process, we can store the physical address assigned in
the chunk tree to the original logical address and a pointer to
btrfs_ordered_sum structure the in the btrfs_bio structure, and then use
this information to rewrite the logical address in the btrfs_ordered_sum
structure directly at I/O completion time in btrfs_record_physical_zoned.
btrfs_rewrite_logical_zoned then simply updates the logical address in
the extent tree and the ordered_extent itself.
The code in btrfs_rewrite_logical_zoned now runs for all data I/O
completions in zoned file systems, which is fine as there is no remapping
to do for non-append writes to conventional zones or for relocation, and
the overhead for quickly breaking out of the loop is very low.
Because zoned file systems now need the ordered_sums structure to
record the actual write location returned by zone append, allocate dummy
structures without the csum array for them when the I/O doesn't use
checksums, and free them when completing the ordered_extent.
Note that the btrfs_bio doesn't grow as the new field are places into
a union that is so far not used for data writes and has plenty of space
left in it.
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>
btrfs_ordered_sum::bytendr stores a logical address. Make that clear by
renaming it to ->logical.
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>
len can't ever be negative, so mark it as an u32 instead of int.
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>
btrfs_split_ordered_extent is only ever asked to split out the beginning
of an ordered_extent (i.e. post == 0). Change it to only take a len to
split out, and switch it to allocate the new extent for the beginning,
as that helps with callers that want to keep a pointer to the
ordered_extent that it is stealing from.
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.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>
The ordered_extent flags are declared as unsigned long, so pass them as
such to btrfs_add_ordered_extent.
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Boris Burkov <boris@bur.io>
[ hch: split from a larger patch ]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently, btrfs_add_ordered_extent allocates a new ordered extent, adds
it to the rb_tree, but doesn't return a referenced pointer to the
caller. There are cases where it is useful for the creator of a new
ordered_extent to hang on to such a pointer, so add a new function
btrfs_alloc_ordered_extent which is the same as
btrfs_add_ordered_extent, except it takes an additional reference count
and returns a pointer to the ordered_extent. Implement
btrfs_add_ordered_extent as btrfs_alloc_ordered_extent followed by
dropping the new reference and handling the IS_ERR case.
The type of flags in btrfs_alloc_ordered_extent and
btrfs_add_ordered_extent is changed from unsigned int to unsigned long
so it's unified with the other ordered extent functions.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_record_physical_zoned relies on a bio->bi_bdev samples in the
bio_end_io handler to find the reverse map for remapping the zone append
write, but stacked block device drivers can and usually do change bi_bdev
when sending on the bio to a lower device. This can happen e.g. with the
nvme-multipath driver when a NVMe SSD sets the shared namespace bit.
But there is no real need for the bdev in btrfs_record_physical_zoned,
as it is only passed to btrfs_rmap_block, which uses it to pick the
mapping to report if there are multiple reverse mappings. As zone
writes can only do simple non-mirror writes right now, and anything
more complex will use the stripe tree there is no chance of the multiple
mappings case actually happening.
Instead open code the subset of btrfs_rmap_block in
btrfs_record_physical_zoned, which also removes a memory allocation and
remove the bdev field in the ordered extent.
Fixes: d8e3fb106f ("btrfs: zoned: use ZONE_APPEND write for zoned mode")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
Given that wait is always set to 1, so remove the argument.
Last use of wait with 0 was in 0c304304fe ("Btrfs: remove
csum_bytes_left").
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>
Now that try_lock_extent() takes a cached_state, plumb the cached_state
through btrfs_try_lock_ordered_range() and then use a cached_state in
btrfs_check_nocow_lock everywhere to avoid extra tree searches on the
extent_io_tree.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For IOCB_NOWAIT we're going to want to use try lock on the extent lock,
and simply bail if there's an ordered extent in the range because the
only choice there is to wait for the ordered extent to complete.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Stefan Roesch <shr@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is defined in ordered-data.h, but is only used in file-item.c.
Move this to file-item.c as it doesn't need to be global.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
finish_func is always set to finish_ordered_fn, so remove it and also
the now pointless and somewhat confusingly named
__endio_write_update_ordered wrapper.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
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>
Currently, we only create ordered extents when ram_bytes == num_bytes
and offset == 0. However, BTRFS_IOC_ENCODED_WRITE writes may create
extents which only refer to a subset of the full unencoded extent, so we
need to plumb these fields through the ordered extent infrastructure and
pass them down to insert_reserved_file_extent().
Since we're changing the btrfs_add_ordered_extent* signature, let's get
rid of the trivial wrappers and add a kernel-doc.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In commit e65f152e43 ("btrfs: refactor how we finish ordered extent io
for endio functions") there was last caller not using 1 for the uptodate
parameter. Now there's only one, passing 1, so we can remove it and
simplify the code.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Store the block device instead of the gendisk in the btrfs_ordered_extent
structure instead of acquiring a reference to it later.
Note: this is from series removing bdgrab/bdput, btrfs is one of the
last users.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Although we already have btrfs_lookup_first_ordered_extent() and
btrfs_lookup_ordered_extent(), they all have their own limitations:
- btrfs_lookup_ordered_extent() can't do extra range check
It's only designed to lookup any ordered extent before certain bytenr.
- btrfs_lookup_first_ordered_extent() may not return the first ordered
extent in the range
It doesn't ensure the first ordered extent is returned.
The existing callers are only interested in exhausting all ordered
extents in a range, the order is not important.
For incoming btrfs_invalidatepage() refactoring, we need a way to
properly iterate all ordered extents in their bytenr order of a range.
So this patch will introduce a new function,
btrfs_lookup_first_ordered_range(), to do ordered extent with bytenr
order awareness and extra range check.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Btrfs has two endio functions to mark certain io range finished for
ordered extents:
- __endio_write_update_ordered()
This is for direct IO
- btrfs_writepage_endio_finish_ordered()
This for buffered IO.
However they go different routines to handle ordered extent io:
- Whether to iterate through all ordered extents
__endio_write_update_ordered() will but
btrfs_writepage_endio_finish_ordered() will not.
In fact, iterating through all ordered extents will benefit later
subpage support, while for current PAGE_SIZE == sectorsize requirement
this behavior makes no difference.
- Whether to update page Private2 flag
__endio_write_update_ordered() will not update page Private2 flag as
for iomap direct IO, the page can not be even mapped.
While btrfs_writepage_endio_finish_ordered() will clear Private2 to
prevent double accounting against btrfs_invalidatepage().
Those differences are pretty subtle, and the ordered extent iterations
code in callers makes code much harder to read.
So this patch will introduce a new function,
btrfs_mark_ordered_io_finished(), to do the heavy lifting:
- Iterate through all ordered extents in the range
- Do the ordered extent accounting
- Queue the work for finished ordered extent
This function has two new feature:
- Proper underflow detection and recovery
The old underflow detection will only detect the problem, then
continue.
No proper info like root/inode/ordered extent info, nor noisy enough
to be caught by fstests.
Furthermore when underflow happens, the ordered extent will never
finish.
New error detection will reset the bytes_left to 0, do proper
kernel warning, and output extra info including root, ino, ordered
extent range, the underflow value.
- Prevent double accounting based on Private2 flag
Now if we find a range without Private2 flag, we will skip to next
range.
As that means someone else has already finished the accounting of
ordered extent.
This makes no difference for current code, but will be a critical part
for incoming subpage support, as we can call
btrfs_mark_ordered_io_finished() for multiple sectors if they are
beyond inode size.
Thus such double accounting prevention is a key feature for subpage.
Now both endio functions only need to call that new function.
And since the only caller of btrfs_dec_test_first_ordered_pending() is
removed, also remove btrfs_dec_test_first_ordered_pending() completely.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is small error in comment about BTRFS_ORDERED_* flags, added in
commit 3c198fe064 ("btrfs: rework the order of
btrfs_ordered_extent::flags") but the fixup did not get merged in time.
The 4 types are for ordered extent itself, not for direct io.
Only 3 types support direct io, REGULAR/NOCOW/PREALLOC.
Fix the comment to reflect that.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Enable zone append writing for zoned mode. When using zone append, a
bio is issued to the start of a target zone and the device decides to
place it inside the zone. Upon completion the device reports the actual
written position back to the host.
Three parts are necessary to enable zone append mode. First, modify the
bio to use REQ_OP_ZONE_APPEND in btrfs_submit_bio_hook() and adjust the
bi_sector to point the beginning of the zone.
Second, record the returned physical address (and disk/partno) to the
ordered extent in end_bio_extent_writepage() after the bio has been
completed. We cannot resolve the physical address to the logical address
because we can neither take locks nor allocate a buffer in this end_bio
context. So, we need to record the physical address to resolve it later
in btrfs_finish_ordered_io().
And finally, rewrite the logical addresses of the extent mapping and
checksum data according to the physical address using btrfs_rmap_block.
If the returned address matches the originally allocated address, we can
skip this rewriting process.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For a zone append write, the device decides the location the data is being
written to. Therefore we cannot ensure that two bios are written
consecutively on the device. In order to ensure that an ordered extent
maps to a contiguous region on disk, we need to maintain a "one bio ==
one ordered extent" rule.
Implement splitting of an ordered extent and extent map on bio submission
to adhere to the rule.
extract_ordered_extent() hooks into btrfs_submit_data_bio() and splits the
corresponding ordered extent so that the ordered extent's region fits into
one bio and the corresponding device limits.
Several sanity checks need to be done in extract_ordered_extent() e.g.
- We cannot split once end_bio'd ordered extent because we cannot divide
ordered->bytes_left for the split ones
- We do not expect a compressed ordered extent
- We should not have checksum list because we omit the list splitting.
Since the function is called before btrfs_wq_submit_bio() or
btrfs_csum_one_bio(), this should be always ensured.
We also need to split an extent map by creating a new one. If not,
unpin_extent_cache() complains about the difference between the start of
the extent map and the file's logical offset.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
There is a long existing bug in the last parameter of
btrfs_add_ordered_extent(), in commit 771ed689d2 ("Btrfs: Optimize
compressed writeback and reads") back to 2008.
In that ancient commit btrfs_add_ordered_extent() expects the @type
parameter to be one of the following:
- BTRFS_ORDERED_REGULAR
- BTRFS_ORDERED_NOCOW
- BTRFS_ORDERED_PREALLOC
- BTRFS_ORDERED_COMPRESSED
But we pass 0 in cow_file_range(), which means BTRFS_ORDERED_IO_DONE.
Ironically extra check in __btrfs_add_ordered_extent() won't set the bit
if we see (type == IO_DONE || type == IO_COMPLETE), and avoid any
obvious bug.
But this still leads to regular COW ordered extent having no bit to
indicate its type in various trace events, rendering REGULAR bit
useless.
[FIX]
Change the following aspects to avoid such problem:
- Reorder btrfs_ordered_extent::flags
Now the type bits go first (REGULAR/NOCOW/PREALLCO/COMPRESSED), then
DIRECT bit, finally extra status bits like IO_DONE/COMPLETE/IOERR.
- Add extra ASSERT() for btrfs_add_ordered_extent_*()
- Remove @type parameter for btrfs_add_ordered_extent_compress()
As the only valid @type here is BTRFS_ORDERED_COMPRESSED.
- Remove the unnecessary special check for IO_DONE/COMPLETE in
__btrfs_add_ordered_extent()
This is just to make the code work, with extra ASSERT(), there are
limited values can be passed in.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The refactoring involves the following modifications:
- Return bool instead of int
- Parameter update for @cached of btrfs_dec_test_first_ordered_pending()
For btrfs_dec_test_first_ordered_pending(), @cached is only used to
return the finished ordered extent.
Rename it to @finished_ret.
- Comment updates
* Change one stale comment
Which still refers to btrfs_dec_test_ordered_pending(), but the
context is calling btrfs_dec_test_first_ordered_pending().
* Follow the common comment style for both functions
Add more detailed descriptions for parameters and the return value
* Move the reason why test_and_set_bit() is used into the call sites
- Change how the return value is calculated
The most anti-human part of the return value is:
if (...)
ret = 1;
...
return ret == 0;
This means, when we set ret to 1, the function returns 0.
Change the local variable name to @finished, and directly return the
value of it.
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 btrfs_lookup_bio_sums() is only called for read bios.
While btrfs_find_ordered_sum() is to search ordered extent sums, which
is only for write path.
This means to read a page we either:
- Submit read bio if it's not uptodate
This means we only need to search csum tree for checksums.
- The page is already uptodate
It can be marked uptodate for previous read, or being marked dirty.
As we always mark page uptodate for dirty page.
In that case, we don't need to submit read bio at all, thus no need
to search any checksums.
Remove the btrfs_find_ordered_sum() call in btrfs_lookup_bio_sums().
And since btrfs_lookup_bio_sums() is the only caller for
btrfs_find_ordered_sum(), also remove the implementation.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Remove local variable that is then used just once and replace it with
fs_info::csum_size.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The fs_info value is 32bit, switch also the local u16 variables. This
leads to a better assembly code generated due to movzwl.
This simple change will shave some bytes on x86_64 and release config:
text data bss dec hex filename
1090000 17980 14912 1122892 11224c pre/btrfs.ko
1089794 17980 14912 1122686 11217e post/btrfs.ko
DELTA: -206
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_get_16 shows up in the system performance profiles (helper to read
16bit values from on-disk structures). This is partially because of the
checksum size that's frequently read along with data reads/writes, other
u16 uses are from item size or directory entries.
Replace all calls to btrfs_super_csum_size by the cached value from
fs_info.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The passed in ordered_extent struct is always well-formed and contains
the inode making the explicit argument redundant.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently regardless of a full or a fast fsync we always wait for ordered
extents to complete, and then start logging the inode after that. However
for fast fsyncs we can just wait for the writeback to complete, we don't
need to wait for the ordered extents to complete since we use the list of
modified extents maps to figure out which extents we must log and we can
get their checksums directly from the ordered extents that are still in
flight, otherwise look them up from the checksums tree.
Until commit b5e6c3e170 ("btrfs: always wait on ordered extents at
fsync time"), for fast fsyncs, we used to start logging without even
waiting for the writeback to complete first, we would wait for it to
complete after logging, while holding a transaction open, which lead to
performance issues when using cgroups and probably for other cases too,
as wait for IO while holding a transaction handle should be avoided as
much as possible. After that, for fast fsyncs, we started to wait for
ordered extents to complete before starting to log, which adds some
latency to fsyncs and we even got at least one report about a performance
drop which bisected to that particular change:
https://lore.kernel.org/linux-btrfs/20181109215148.GF23260@techsingularity.net/
This change makes fast fsyncs only wait for writeback to finish before
starting to log the inode, instead of waiting for both the writeback to
finish and for the ordered extents to complete. This brings back part of
the logic we had that extracts checksums from in flight ordered extents,
which are not yet in the checksums tree, and making sure transaction
commits wait for the completion of ordered extents previously logged
(by far most of the time they have already completed by the time a
transaction commit starts, resulting in no wait at all), to avoid any
data loss if an ordered extent completes after the transaction used to
log an inode is committed, followed by a power failure.
When there are no other tasks accessing the checksums and the subvolume
btrees, the ordered extent completion is pretty fast, typically taking
100 to 200 microseconds only in my observations. However when there are
other tasks accessing these btrees, ordered extent completion can take a
lot more time due to lock contention on nodes and leaves of these btrees.
I've seen cases over 2 milliseconds, which starts to be significant. In
particular when we do have concurrent fsyncs against different files there
is a lot of contention on the checksums btree, since we have many tasks
writing the checksums into the btree and other tasks that already started
the logging phase are doing lookups for checksums in the btree.
This change also turns all ranged fsyncs into full ranged fsyncs, which
is something we already did when not using the NO_HOLES features or when
doing a full fsync. This is to guarantee we never miss checksums due to
writeback having been triggered only for a part of an extent, and we end
up logging the full extent but only checksums for the written range, which
results in missing checksums after log replay. Allowing ranged fsyncs to
operate again only in the original range, when using the NO_HOLES feature
and doing a fast fsync is doable but requires some non trivial changes to
the writeback path, which can always be worked on later if needed, but I
don't think they are a very common use case.
Several tests were performed using fio for different numbers of concurrent
jobs, each writing and fsyncing its own file, for both sequential and
random file writes. The tests were run on bare metal, no virtualization,
on a box with 12 cores (Intel i7-8700), 64Gb of RAM and a NVMe device,
with a kernel configuration that is the default of typical distributions
(debian in this case), without debug options enabled (kasan, kmemleak,
slub debug, debug of page allocations, lock debugging, etc).
The following script that calls fio was used:
$ cat test-fsync.sh
#!/bin/bash
DEV=/dev/nvme0n1
MNT=/mnt/btrfs
MOUNT_OPTIONS="-o ssd -o space_cache=v2"
MKFS_OPTIONS="-d single -m single"
if [ $# -ne 5 ]; then
echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ BLOCK_SIZE [write|randwrite]"
exit 1
fi
NUM_JOBS=$1
FILE_SIZE=$2
FSYNC_FREQ=$3
BLOCK_SIZE=$4
WRITE_MODE=$5
if [ "$WRITE_MODE" != "write" ] && [ "$WRITE_MODE" != "randwrite" ]; then
echo "Invalid WRITE_MODE, must be 'write' or 'randwrite'"
exit 1
fi
cat <<EOF > /tmp/fio-job.ini
[writers]
rw=$WRITE_MODE
fsync=$FSYNC_FREQ
fallocate=none
group_reporting=1
direct=0
bs=$BLOCK_SIZE
ioengine=sync
size=$FILE_SIZE
directory=$MNT
numjobs=$NUM_JOBS
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
mount $MOUNT_OPTIONS $DEV $MNT
fio /tmp/fio-job.ini
umount $MNT
The results were the following:
*************************
*** sequential writes ***
*************************
==== 1 job, 8GiB file, fsync frequency 1, block size 64KiB ====
Before patch:
WRITE: bw=36.6MiB/s (38.4MB/s), 36.6MiB/s-36.6MiB/s (38.4MB/s-38.4MB/s), io=8192MiB (8590MB), run=223689-223689msec
After patch:
WRITE: bw=40.2MiB/s (42.1MB/s), 40.2MiB/s-40.2MiB/s (42.1MB/s-42.1MB/s), io=8192MiB (8590MB), run=203980-203980msec
(+9.8%, -8.8% runtime)
==== 2 jobs, 4GiB files, fsync frequency 1, block size 64KiB ====
Before patch:
WRITE: bw=35.8MiB/s (37.5MB/s), 35.8MiB/s-35.8MiB/s (37.5MB/s-37.5MB/s), io=8192MiB (8590MB), run=228950-228950msec
After patch:
WRITE: bw=43.5MiB/s (45.6MB/s), 43.5MiB/s-43.5MiB/s (45.6MB/s-45.6MB/s), io=8192MiB (8590MB), run=188272-188272msec
(+21.5% throughput, -17.8% runtime)
==== 4 jobs, 2GiB files, fsync frequency 1, block size 64KiB ====
Before patch:
WRITE: bw=50.1MiB/s (52.6MB/s), 50.1MiB/s-50.1MiB/s (52.6MB/s-52.6MB/s), io=8192MiB (8590MB), run=163446-163446msec
After patch:
WRITE: bw=64.5MiB/s (67.6MB/s), 64.5MiB/s-64.5MiB/s (67.6MB/s-67.6MB/s), io=8192MiB (8590MB), run=126987-126987msec
(+28.7% throughput, -22.3% runtime)
==== 8 jobs, 1GiB files, fsync frequency 1, block size 64KiB ====
Before patch:
WRITE: bw=64.0MiB/s (68.1MB/s), 64.0MiB/s-64.0MiB/s (68.1MB/s-68.1MB/s), io=8192MiB (8590MB), run=126075-126075msec
After patch:
WRITE: bw=86.8MiB/s (91.0MB/s), 86.8MiB/s-86.8MiB/s (91.0MB/s-91.0MB/s), io=8192MiB (8590MB), run=94358-94358msec
(+35.6% throughput, -25.2% runtime)
==== 16 jobs, 512MiB files, fsync frequency 1, block size 64KiB ====
Before patch:
WRITE: bw=79.8MiB/s (83.6MB/s), 79.8MiB/s-79.8MiB/s (83.6MB/s-83.6MB/s), io=8192MiB (8590MB), run=102694-102694msec
After patch:
WRITE: bw=107MiB/s (112MB/s), 107MiB/s-107MiB/s (112MB/s-112MB/s), io=8192MiB (8590MB), run=76446-76446msec
(+34.1% throughput, -25.6% runtime)
==== 32 jobs, 512MiB files, fsync frequency 1, block size 64KiB ====
Before patch:
WRITE: bw=93.2MiB/s (97.7MB/s), 93.2MiB/s-93.2MiB/s (97.7MB/s-97.7MB/s), io=16.0GiB (17.2GB), run=175836-175836msec
After patch:
WRITE: bw=111MiB/s (117MB/s), 111MiB/s-111MiB/s (117MB/s-117MB/s), io=16.0GiB (17.2GB), run=147001-147001msec
(+19.1% throughput, -16.4% runtime)
==== 64 jobs, 512MiB files, fsync frequency 1, block size 64KiB ====
Before patch:
WRITE: bw=108MiB/s (114MB/s), 108MiB/s-108MiB/s (114MB/s-114MB/s), io=32.0GiB (34.4GB), run=302656-302656msec
After patch:
WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=246003-246003msec
(+23.1% throughput, -18.7% runtime)
************************
*** random writes ***
************************
==== 1 job, 8GiB file, fsync frequency 16, block size 4KiB ====
Before patch:
WRITE: bw=11.5MiB/s (12.0MB/s), 11.5MiB/s-11.5MiB/s (12.0MB/s-12.0MB/s), io=8192MiB (8590MB), run=714281-714281msec
After patch:
WRITE: bw=11.6MiB/s (12.2MB/s), 11.6MiB/s-11.6MiB/s (12.2MB/s-12.2MB/s), io=8192MiB (8590MB), run=705959-705959msec
(+0.9% throughput, -1.7% runtime)
==== 2 jobs, 4GiB files, fsync frequency 16, block size 4KiB ====
Before patch:
WRITE: bw=12.8MiB/s (13.5MB/s), 12.8MiB/s-12.8MiB/s (13.5MB/s-13.5MB/s), io=8192MiB (8590MB), run=638101-638101msec
After patch:
WRITE: bw=13.1MiB/s (13.7MB/s), 13.1MiB/s-13.1MiB/s (13.7MB/s-13.7MB/s), io=8192MiB (8590MB), run=625374-625374msec
(+2.3% throughput, -2.0% runtime)
==== 4 jobs, 2GiB files, fsync frequency 16, block size 4KiB ====
Before patch:
WRITE: bw=15.4MiB/s (16.2MB/s), 15.4MiB/s-15.4MiB/s (16.2MB/s-16.2MB/s), io=8192MiB (8590MB), run=531146-531146msec
After patch:
WRITE: bw=17.8MiB/s (18.7MB/s), 17.8MiB/s-17.8MiB/s (18.7MB/s-18.7MB/s), io=8192MiB (8590MB), run=460431-460431msec
(+15.6% throughput, -13.3% runtime)
==== 8 jobs, 1GiB files, fsync frequency 16, block size 4KiB ====
Before patch:
WRITE: bw=19.9MiB/s (20.8MB/s), 19.9MiB/s-19.9MiB/s (20.8MB/s-20.8MB/s), io=8192MiB (8590MB), run=412664-412664msec
After patch:
WRITE: bw=22.2MiB/s (23.3MB/s), 22.2MiB/s-22.2MiB/s (23.3MB/s-23.3MB/s), io=8192MiB (8590MB), run=368589-368589msec
(+11.6% throughput, -10.7% runtime)
==== 16 jobs, 512MiB files, fsync frequency 16, block size 4KiB ====
Before patch:
WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=8192MiB (8590MB), run=279924-279924msec
After patch:
WRITE: bw=30.4MiB/s (31.9MB/s), 30.4MiB/s-30.4MiB/s (31.9MB/s-31.9MB/s), io=8192MiB (8590MB), run=269258-269258msec
(+3.8% throughput, -3.8% runtime)
==== 32 jobs, 512MiB files, fsync frequency 16, block size 4KiB ====
Before patch:
WRITE: bw=36.9MiB/s (38.7MB/s), 36.9MiB/s-36.9MiB/s (38.7MB/s-38.7MB/s), io=16.0GiB (17.2GB), run=443581-443581msec
After patch:
WRITE: bw=41.6MiB/s (43.6MB/s), 41.6MiB/s-41.6MiB/s (43.6MB/s-43.6MB/s), io=16.0GiB (17.2GB), run=394114-394114msec
(+12.7% throughput, -11.2% runtime)
==== 64 jobs, 512MiB files, fsync frequency 16, block size 4KiB ====
Before patch:
WRITE: bw=45.9MiB/s (48.1MB/s), 45.9MiB/s-45.9MiB/s (48.1MB/s-48.1MB/s), io=32.0GiB (34.4GB), run=714614-714614msec
After patch:
WRITE: bw=48.8MiB/s (51.1MB/s), 48.8MiB/s-48.8MiB/s (51.1MB/s-51.1MB/s), io=32.0GiB (34.4GB), run=672087-672087msec
(+6.3% throughput, -6.0% runtime)
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Simply forwards its argument so let's get rid of one extra BTRFS_I by
taking btrfs_inode directly.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It doesn't really need vfs_inode but btrfs_inode.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It simpy forwards its inode argument to __btrfs_add_ordered_extent which
already takes btrfs_inode.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Preparation to converting its callers to taking btrfs_inode.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It doesn't use the generic vfs inode for anything use btrfs_inode
directly.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The 'trans_list' member of an ordered extent was used to keep track of the
ordered extents for which a transaction commit had to wait. These were
ordered extents that were started and logged by an fsync. However we don't
do that anymore and before we stopped doing it we changed the approach to
wait for the ordered extents in commit 161c3549b4 ("Btrfs: change how
we wait for pending ordered extents"), which stopped using that list and
therefore the 'trans_list' member is not used anymore since that commit.
So just remove it since it's doing nothing and making each ordered extent
structure waste memory (2 pointers).
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The 'log_list' member of an ordered extent was used keep track of which
ordered extents we needed to wait after logging metadata, but is not used
anymore since commit 5636cf7d6d ("btrfs: remove the logged extents
infrastructure"), as we now always wait on ordered extent completion
before logging metadata. So just remove it since it's doing nothing and
making each ordered extent structure waste more memory (2 pointers).
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
The following simple workload from fsstress can lead to qgroup reserved
data space leak:
0/0: creat f0 x:0 0 0
0/0: creat add id=0,parent=-1
0/1: write f0[259 1 0 0 0 0] [600030,27288] 0
0/4: dwrite - xfsctl(XFS_IOC_DIOINFO) f0[259 1 0 0 64 627318] return 25, fallback to stat()
0/4: dwrite f0[259 1 0 0 64 627318] [610304,106496] 0
This would cause btrfs qgroup to leak 20480 bytes for data reserved
space. If btrfs qgroup limit is enabled, such leak can lead to
unexpected early EDQUOT and unusable space.
[CAUSE]
When doing direct IO, kernel will try to writeback existing buffered
page cache, then invalidate them:
generic_file_direct_write()
|- filemap_write_and_wait_range();
|- invalidate_inode_pages2_range();
However for btrfs, the bi_end_io hook doesn't finish all its heavy work
right after bio ends. In fact, it delays its work further:
submit_extent_page(end_io_func=end_bio_extent_writepage);
end_bio_extent_writepage()
|- btrfs_writepage_endio_finish_ordered()
|- btrfs_init_work(finish_ordered_fn);
<<< Work queue execution >>>
finish_ordered_fn()
|- btrfs_finish_ordered_io();
|- Clear qgroup bits
This means, when filemap_write_and_wait_range() returns,
btrfs_finish_ordered_io() is not guaranteed to be executed, thus the
qgroup bits for related range are not cleared.
Now into how the leak happens, this will only focus on the overlapping
part of buffered and direct IO part.
1. After buffered write
The inode had the following range with QGROUP_RESERVED bit:
596 616K
|///////////////|
Qgroup reserved data space: 20K
2. Writeback part for range [596K, 616K)
Write back finished, but btrfs_finish_ordered_io() not get called
yet.
So we still have:
596K 616K
|///////////////|
Qgroup reserved data space: 20K
3. Pages for range [596K, 616K) get released
This will clear all qgroup bits, but don't update the reserved data
space.
So we have:
596K 616K
| |
Qgroup reserved data space: 20K
That number doesn't match the qgroup bit range anymore.
4. Dio prepare space for range [596K, 700K)
Qgroup reserved data space for that range, we got:
596K 616K 700K
|///////////////|///////////////////////|
Qgroup reserved data space: 20K + 104K = 124K
5. btrfs_finish_ordered_range() gets executed for range [596K, 616K)
Qgroup free reserved space for that range, we got:
596K 616K 700K
| |///////////////////////|
We need to free that range of reserved space.
Qgroup reserved data space: 124K - 20K = 104K
6. btrfs_finish_ordered_range() gets executed for range [596K, 700K)
However qgroup bit for range [596K, 616K) is already cleared in
previous step, so we only free 84K for qgroup reserved space.
596K 616K 700K
| | |
We need to free that range of reserved space.
Qgroup reserved data space: 104K - 84K = 20K
Now there is no way to release that 20K unless disabling qgroup or
unmounting the fs.
[FIX]
This patch will change the timing of btrfs_qgroup_release/free_data()
call. Here it uses buffered COW write as an example.
The new timing | The old timing
----------------------------------------+---------------------------------------
btrfs_buffered_write() | btrfs_buffered_write()
|- btrfs_qgroup_reserve_data() | |- btrfs_qgroup_reserve_data()
|
btrfs_run_delalloc_range() | btrfs_run_delalloc_range()
|- btrfs_add_ordered_extent() |
|- btrfs_qgroup_release_data() |
The reserved is passed into |
btrfs_ordered_extent structure |
|
btrfs_finish_ordered_io() | btrfs_finish_ordered_io()
|- The reserved space is passed to | |- btrfs_qgroup_release_data()
btrfs_qgroup_record | The resereved space is passed
| to btrfs_qgroup_recrod
|
btrfs_qgroup_account_extents() | btrfs_qgroup_account_extents()
|- btrfs_qgroup_free_refroot() | |- btrfs_qgroup_free_refroot()
The point of such change is to ensure, when ordered extents are
submitted, the qgroup reserved space is already released, to keep the
timing aligned with file_write_and_wait_range().
So that qgroup data reserved space is all bound to btrfs_ordered_extent
and solve the timing mismatch.
Fixes: f695fdcef8 ("btrfs: qgroup: Introduce functions to release/free qgroup reserve data space")
Suggested-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The tree pointer can be safely read from the inode so we can drop the
redundant argument from btrfs_lock_and_flush_ordered_range.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we have a safe way to update the isize, remove all of this code
as it's no longer needed.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
ordered->start, ordered->len, and ordered->disk_len correspond to
fi->disk_bytenr, fi->num_bytes, and fi->disk_num_bytes, respectively.
It's confusing to translate between the two naming schemes. Since a
btrfs_ordered_extent is basically a pending btrfs_file_extent_item,
let's make the former use the naming from the latter.
Note that I didn't touch the names in tracepoints just in case there are
scripts depending on the current naming.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When doing a device replace, while at scrub.c:scrub_enumerate_chunks(), we
set the block group to RO mode and then wait for any ongoing writes into
extents of the block group to complete. While doing that wait we overwrite
the value of the variable 'ret' and can break out of the loop if an error
happens without turning the block group back into RW mode. So what happens
is the following:
1) btrfs_inc_block_group_ro() returns 0, meaning it set the block group
to RO mode (its ->ro field set to 1 or incremented to some value > 1);
2) Then btrfs_wait_ordered_roots() returns a value > 0;
3) Then if either joining or committing the transaction fails, we break
out of the loop wihtout calling btrfs_dec_block_group_ro(), leaving
the block group in RO mode forever.
To fix this, just remove the code that waits for ongoing writes to extents
of the block group, since it's not needed because in the initial setup
phase of a device replace operation, before starting to find all chunks
and their extents, we set the target device for replace while holding
fs_info->dev_replace->rwsem, which ensures that after releasing that
semaphore, any writes into the source device are made to the target device
as well (__btrfs_map_block() guarantees that). So while at
scrub_enumerate_chunks() we only need to worry about finding and copying
extents (from the source device to the target device) that were written
before we started the device replace operation.
Fixes: f0e9b7d640 ("Btrfs: fix race setting block group readonly during device replace")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
BTRFS has the implicit assumption that a checksum in btrfs_orderd_sums
is 4 bytes. While this is true for CRC32C, it is not for any other
checksum.
Change the data type to be a byte array and adjust loop index
calculation accordingly.
This includes moving the adjustment of 'index' by 'ins_size' in
btrfs_csum_file_blocks() before dividing 'ins_size' by the checksum
size, because before this patch the 'sums' member of 'struct
btrfs_ordered_sum' was 4 Bytes in size and afterwards it is only one
byte.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
