During inspection of the return path for replay I noticed that we don't
actually abort the transaction if we get a failure during replay. This
isn't a problem necessarily, as we properly return the error and will
fail to mount. However we still leave this dangling transaction that
could conceivably be committed without thinking there was an error.
We were using btrfs_handle_fs_error() here, but that pre-dates the
transaction abort code. Simply replace the btrfs_handle_fs_error()
calls with transaction aborts, so we still know where exactly things
went wrong, and add a few in some other un-handled error cases.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
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>
Fix memdup.cocci warning:
fs/btrfs/zoned.c:1198:23-30: WARNING opportunity for kmemdup
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Kai Song <songkai01@inspur.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For compressed write, we use a mechanism called async COW, which unlike
regular run_delalloc_cow() or cow_file_range() will also unlock the
first page.
This mechanism allows us to continue handling next ranges, without
waiting for the time consuming compression.
But this has a problem for subpage case, as we could have the following
delalloc range for a page:
0 32K 64K
| |///////| |///////|
\- A \- B
In the above case, if we pass both ranges to cow_file_range_async(),
both range A and range B will try to unlock the full page [0, 64K).
And which one finishes later than the other one will try to do other
page operations like end_page_writeback() on a unlocked page, triggering
VM layer BUG_ON().
To make subpage compression work at least partially, here we add another
restriction for it, only allow compression if the delalloc range is
fully page aligned.
By that, async extent is always ensured to unlock the first page
exclusively, just like it used to be for regular sectorsize.
In theory, we only need to make sure the delalloc range fully covers its
first page, but the tail page will be locked anyway, blocking later
writeback until the compression finishes.
Thus here we choose to make sure the range is fully page aligned before
doing the compression.
In the future, we could optimize the situation by properly increasing
subpage::writers number for the locked page, but that also means we need
to change how we run delalloc range of page.
(Instead of running each delalloc range we hit, we need to find and lock
all delalloc ranges covering the page, then run each of them).
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
With experimental subpage compression enabled, a simple fsstress can
lead to self deadlock on page 720896:
mkfs.btrfs -f -s 4k $dev > /dev/null
mount $dev -o compress $mnt
$fsstress -p 1 -n 100 -w -d $mnt -v -s 1625511156
[CAUSE]
If we have a file layout looks like below:
0 32K 64K 96K 128K
|//| |///////////////|
4K
Then we run delalloc range for the inode, it will:
- Call find_lock_delalloc_range() with @delalloc_start = 0
Then we got a delalloc range [0, 4K).
This range will be COWed.
- Call find_lock_delalloc_range() again with @delalloc_start = 4K
Since find_lock_delalloc_range() never cares whether the range
is still inside page range [0, 64K), it will return range [64K, 128K).
This range meets the condition for subpage compression, will go
through async COW path.
And async COW path will return @page_started.
But that @page_started is now for range [64K, 128K), not for range
[0, 64K).
- writepage_dellloc() returned 1 for page [0, 64K)
Thus page [0, 64K) will not be unlocked, nor its page dirty status
will be cleared.
Next time when we try to lock page [0, 64K) we will deadlock, as there
is no one to release page [0, 64K).
This problem will never happen for regular page size as one page only
contains one sector. After the first find_lock_delalloc_range() call,
the @delalloc_end will go beyond @page_end no matter if we found a
delalloc range or not
Thus this bug only happens for subpage, as now we need multiple runs to
exhaust the delalloc range of a page.
[FIX]
Fix the problem by ensuring the delalloc range we ran at least started
inside @locked_page.
So that we will never get incorrect @page_started.
And to prevent such problem from happening again:
- Make find_lock_delalloc_range() return false if the found range is
beyond @end value passed in.
Since @end will be utilized now, add an ASSERT() to ensure we pass
correct @end into find_lock_delalloc_range().
This also means, for selftests we needs to populate @end before calling
find_lock_delalloc_range().
- New ASSERT() in find_lock_delalloc_range()
Now we will make sure the @start/@end passed in at least covers part
of the page.
- New ASSERT() in run_delalloc_range()
To make sure the range at least starts inside @locked page.
- Use @delalloc_start as proper cursor, while @delalloc_end is always
reset to @page_end.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are several call sites of extent_clear_unlock_delalloc() which get
@locked_page = NULL.
So that extent_clear_unlock_delalloc() will try to call
process_one_page() to unlock every page even the first page is not
locked by btrfs_page_start_writer_lock().
This will trigger an ASSERT() in btrfs_subpage_end_and_test_writer() as
previously we require every page passed to
btrfs_subpage_end_and_test_writer() to be locked by
btrfs_page_start_writer_lock().
But compression path doesn't go that way.
Thankfully it's not hard to distinguish page locked by lock_page() and
btrfs_page_start_writer_lock().
So do the check in btrfs_subpage_end_and_test_writer() so now it can
handle both cases well.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pages passed to __extent_writepage() are always locked, but they may be
locked by different functions.
There are two types of locked page for __extent_writepage():
- Page locked by plain lock_page()
It should not have any subpage::writers count.
Can be unlocked by unlock_page().
This is the most common locked page for __extent_writepage() called
inside extent_write_cache_pages() or extent_write_full_page().
Rarer cases include the @locked_page from extent_write_locked_range().
- Page locked by lock_delalloc_pages()
There is only one caller, all pages except @locked_page for
extent_write_locked_range().
In this case, we have to call subpage helper to handle the case.
So here we introduce a helper, btrfs_page_unlock_writer(), to allow
__extent_writepage() to unlock different locked pages.
And since for all other callers of __extent_writepage() their pages are
ensured to be locked by lock_page(), also add an extra check for
epd::extent_locked to unlock such pages directly.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are several problems in lzo_compress_pages() preventing it from
being subpage compatible:
- No page offset is calculated when reading from inode pages
For subpage case, we could have @start which is not aligned to
PAGE_SIZE.
Thus the destination where we read data from must take offset in page
into consideration.
- The padding for segment header is bound to PAGE_SIZE
This means, for subpage case we can skip several corners where on x86
machines we need to add padding zeros.
The rework will:
- Update the comment to replace "page" with "sector"
- Introduce a new helper, copy_compressed_data_to_page(), to do the copy
So that we don't need to bother page switching for both input and
output.
Now in lzo_compress_pages() we only care about page switching for
input, while in copy_compressed_data_to_page() we only care about the
page switching for output.
- Only one main cursor
For lzo_compress_pages() we use @cur_in as main cursor.
It will be the file offset we are currently at.
All other helper variables will be only declared inside the loop.
For copy_compressed_data_to_page() it's similar, we will have
@cur_out at the main cursor, which records how many bytes are in the
output.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Introduce a new helper, submit_uncompressed_range(), for async cow cases
where we fallback to COW.
There are some new updates introduced to the helper:
- Proper locked_page detection
It's possible that the async_extent range doesn't cover the locked
page. In that case we shouldn't unlock the locked page.
In the new helper, we will ensure that we only unlock the locked page
when:
* The locked page covers part of the async_extent range
* The locked page is not unlocked by cow_file_range() nor
extent_write_locked_range()
This also means extra comments are added focusing on the page locking.
- Add extra comment on some rare parameter used.
We use @unlock_page = 0 for cow_file_range(), where only two call
sites doing the same thing, including the new helper.
It's definitely worth some comments.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are two sites are not subpage compatible yet for
extent_write_locked_range():
- How @nr_pages are calculated
For subpage we can have the following range with 64K page size:
0 32K 64K 96K 128K
| |////|/////| |
In that case, although 96K - 32K == 64K, thus it looks like one page
is enough, but the range spans two pages, not one.
Fix it by doing proper round_up() and round_down() to calculate
@nr_pages.
Also add some extra ASSERT()s to ensure the range passed in is already
aligned.
- How the page end is calculated
Currently we just use cur + PAGE_SIZE - 1 to calculate the page end.
Which can't handle the above range layout, and will trigger ASSERT()
in btrfs_writepage_endio_finish_ordered(), as the range is no longer
covered by the page range.
Fix it by taking page end into consideration.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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>
In function compress_file_range(), when the compression is finished, the
function just rounds up @total_in to PAGE_SIZE. This is fine for
regular sectorsize == PAGE_SIZE case, but not for subpage.
Just change the ALIGN(, PAGE_SIZE) to round_up(, sectorsize) so that
both regular sectorsize and subpage sectorsize will be happy.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are several cleanups for extent_write_locked_range(), most of them
are pure cleanups, but with some preparation for future subpage support.
- Add a proper comment for which call sites are suitable
Unlike regular synchronized extent write back, if async COW or zoned
COW happens, we have all pages in the range still locked.
Thus for those (only) two call sites, we need this function to submit
page content into bios and submit them.
- Remove @mode parameter
All the existing two call sites pass WB_SYNC_ALL. No need for @mode
parameter.
- Better error handling
Currently if we hit an error during the page iteration loop, we
overwrite @ret, causing only the last error can be recorded.
Here we add @found_error and @first_error variable to record if we hit
any error, and the first error we hit.
So the first error won't get lost.
- Don't reuse @start as the cursor
We reuse the parameter @start as the cursor to iterate the range, not
a big problem, but since we're here, introduce a proper @cur as the
cursor.
- Remove impossible branch
Since all pages are still locked after the ordered extent is inserted,
there is no way that pages can get its dirty bit cleared.
Remove the branch where page is not dirty and replace it with an
ASSERT().
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have a big chunk of code inside a while() loop, with tons of strange
jumps for error handling. It's definitely not to the code standard of
today. Move the code into a new function, submit_one_async_extent().
Since we're here, also do the following changes:
- Comment style change
To follow the current scheme
- Don't fallback to non-compressed write then hitting ENOSPC
If we hit ENOSPC for compressed write, how could we reserve more space
for non-compressed write?
Thus we go error path directly.
This removes the retry: label.
- Add more comment for super long parameter list
Explain which parameter is for, so we don't need to check the
prototype.
- Move the error handling to submit_one_async_extent()
Thus no strange code like:
out_free:
...
goto again;
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
As the last caller in compression.c has been removed, we don't need that
function anymore.
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>
Since async_extent holds the compressed page, it would trigger the new
ASSERT() in btrfs_mark_ordered_io_finished() which checks that the range
is inside the page.
Now btrfs_writepage_endio_finish_ordered() can accept @page == NULL,
just pass NULL to btrfs_writepage_endio_finish_ordered().
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For structure async_chunk, we use a very strange member layout to grab
structure async_cow who owns this async_chunk.
At initialization, it goes like this:
async_chunk[i].pending = &ctx->num_chunks;
Then at async_cow_free() we do a super weird freeing:
/*
* Since the pointer to 'pending' is at the beginning of the array of
* async_chunk's, freeing it ensures the whole array has been freed.
*/
if (atomic_dec_and_test(async_chunk->pending))
kvfree(async_chunk->pending);
This is absolutely an abuse of kvfree().
Replace async_chunk::pending with async_chunk::async_cow, so that we can
grab the async_cow structure directly, without this strange dancing.
And with this change, there is no requirement for any specific member
location.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In function __extent_writepage() we always pass page start to
@delalloc_start for writepage_delalloc().
Thus we don't really need @delalloc_start parameter as we can extract it
from @page.
Remove @delalloc_start parameter and make __extent_writepage() to
declare @page_start and @page_end as const.
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>
When logging a directory and inserting a batch of directory items, we are
copying the data of each item from a leaf in the fs/subvolume tree to a
leaf in a log tree, separately. This is not really needed, since we are
copying from a contiguous memory area into another one, so we can use a
single copy operation to copy all items at once.
This patch is part of a small patchset that is comprised of the following
patches:
btrfs: loop only once over data sizes array when inserting an item batch
btrfs: unexport setup_items_for_insert()
btrfs: use single bulk copy operations when logging directories
This is patch 3/3.
The following test was used to compare performance of a branch without the
patchset versus one branch that has the whole patchset applied:
$ cat dir-fsync-test.sh
#!/bin/bash
DEV=/dev/nvme0n1
MNT=/mnt/nvme0n1
NUM_NEW_FILES=1000000
NUM_FILE_DELETES=1000
LEAF_SIZE=16K
mkfs.btrfs -f -n $LEAF_SIZE $DEV
mount -o ssd $DEV $MNT
mkdir $MNT/testdir
for ((i = 1; i <= $NUM_NEW_FILES; i++)); do
echo -n > $MNT/testdir/file_$i
done
# Fsync the directory, this will log the new dir items and the inodes
# they point to, because these are new inodes.
start=$(date +%s%N)
xfs_io -c "fsync" $MNT/testdir
end=$(date +%s%N)
dur=$(( (end - start) / 1000000 ))
echo "dir fsync took $dur ms after adding $NUM_NEW_FILES files"
# sync to force transaction commit and wipeout the log.
sync
del_inc=$(( $NUM_NEW_FILES / $NUM_FILE_DELETES ))
for ((i = 1; i <= $NUM_NEW_FILES; i += $del_inc)); do
rm -f $MNT/testdir/file_$i
done
# Fsync the directory, this will only log dir items, there are no
# dentries pointing to new inodes.
start=$(date +%s%N)
xfs_io -c "fsync" $MNT/testdir
end=$(date +%s%N)
dur=$(( (end - start) / 1000000 ))
echo "dir fsync took $dur ms after deleting $NUM_FILE_DELETES files"
umount $MNT
The tests were run on a non-debug kernel (Debian's default kernel config)
and were the following:
*** with a leaf size of 16K, before patchset ***
dir fsync took 8482 ms after adding 1000000 files
dir fsync took 166 ms after deleting 1000 files
*** with a leaf size of 16K, after patchset ***
dir fsync took 8196 ms after adding 1000000 files (-3.4%)
dir fsync took 143 ms after deleting 1000 files (-14.9%)
*** with a leaf size of 64K, before patchset ***
dir fsync took 12851 ms after adding 1000000 files
dir fsync took 466 ms after deleting 1000 files
*** with a leaf size of 64K, after patchset ***
dir fsync took 12287 ms after adding 1000000 files (-4.5%)
dir fsync took 414 ms after deleting 1000 files (-11.8%)
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since setup_items_for_insert() is not used anymore outside of ctree.c,
make it static and remove its prototype from ctree.h. This also requires
to move the definition of setup_item_for_insert() from ctree.h to ctree.c
and move down btrfs_duplicate_item() so that it's defined after
setup_items_for_insert().
Further, since setup_item_for_insert() is used outside ctree.c, rename it
to btrfs_setup_item_for_insert().
This patch is part of a small patchset that is comprised of the following
patches:
btrfs: loop only once over data sizes array when inserting an item batch
btrfs: unexport setup_items_for_insert()
btrfs: use single bulk copy operations when logging directories
This is patch 2/3 and performance results, and the specific tests, are
included in the changelog of patch 3/3.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When inserting a batch of items into a btree, we end up looping over the
data sizes array 3 times:
1) Once in the caller of btrfs_insert_empty_items(), when it populates the
array with the data sizes for each item;
2) Once at btrfs_insert_empty_items() to sum the elements of the data
sizes array and compute the total data size;
3) And then once again at setup_items_for_insert(), where we do exactly
the same as what we do at btrfs_insert_empty_items(), to compute the
total data size.
That is not bad for small arrays, but when the arrays have hundreds of
elements, the time spent on looping is not negligible. For example when
doing batch inserts of delayed items for dir index items or when logging
a directory, it's common to have 200 to 260 dir index items in a single
batch when using a leaf size of 16K and using file names between 8 and 12
characters. For a 64K leaf size, multiply that by 4. Taking into account
that during directory logging or when flushing delayed dir index items we
can have many of those large batches, the time spent on the looping adds
up quickly.
It's also more important to avoid it at setup_items_for_insert(), since
we are holding a write lock on a leaf and, in some cases, on upper nodes
of the btree, which causes us to block other tasks that want to access
the leaf and nodes for longer than necessary.
So change the code so that setup_items_for_insert() and
btrfs_insert_empty_items() no longer compute the total data size, and
instead rely on the caller to supply it. This makes us loop over the
array only once, where we can both populate the data size array and
compute the total data size, taking advantage of spatial and temporal
locality. To make this more manageable, use a structure to contain
all the relevant details for a batch of items (keys array, data sizes
array, total data size, number of items), and use it as an argument
for btrfs_insert_empty_items() and setup_items_for_insert().
This patch is part of a small patchset that is comprised of the following
patches:
btrfs: loop only once over data sizes array when inserting an item batch
btrfs: unexport setup_items_for_insert()
btrfs: use single bulk copy operations when logging directories
This is patch 1/3 and performance results, and the specific tests, are
included in the changelog of patch 3/3.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We can grab fs_info reliably from btrfs_raid_bio::bioc, as the bioc is
always passed into alloc_rbio(), and only get released when the raid bio
is released.
Remove btrfs_raid_bio::fs_info member, and cleanup all the @fs_info
parameters for alloc_rbio() callers.
Reviewed-by: Nikolay Borisov <nborisov@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>
Currently btrfs_io_context::fs_info is only initialized in
btrfs_map_bio, but there are call sites like btrfs_map_sblock() which
calls __btrfs_map_block() directly, leaving bioc::fs_info uninitialized
(NULL).
Currently this is fine, but later cleanup will rely on bioc::fs_info to
grab fs_info, and this can be a hidden problem for such usage.
This patch will remove such hidden uninitialized member by always
assigning bioc::fs_info at alloc_btrfs_io_context().
Reviewed-by: Nikolay Borisov <nborisov@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>
We currently use lockdep_assert_held() at btrfs_assert_tree_locked(), and
that checks that we hold a lock either in read mode or write mode.
However in all contexts we use btrfs_assert_tree_locked(), we actually
want to check if we are holding a write lock on the extent buffer's rw
semaphore - it would be a bug if in any of those contexts we were holding
a read lock instead.
So change btrfs_assert_tree_locked() to use lockdep_assert_held_write()
instead and, to make it more explicit, rename btrfs_assert_tree_locked()
to btrfs_assert_tree_write_locked(), so that it's clear we want to check
we are holding a write lock.
For now there are no contexts where we want to assert that we must have
a read lock, but in case that is needed in the future, we can add a new
helper function that just calls out lockdep_assert_held_read().
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We got the following lockdep splat while running fstests (specifically
btrfs/003 and btrfs/020 in a row) with the new rc. This was uncovered
by 87579e9b7d ("loop: use worker per cgroup instead of kworker") which
converted loop to using workqueues, which comes with lockdep
annotations that don't exist with kworkers. The lockdep splat is as
follows:
WARNING: possible circular locking dependency detected
5.14.0-rc2-custom+ #34 Not tainted
------------------------------------------------------
losetup/156417 is trying to acquire lock:
ffff9c7645b02d38 ((wq_completion)loop0){+.+.}-{0:0}, at: flush_workqueue+0x84/0x600
but task is already holding lock:
ffff9c7647395468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x650 [loop]
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #5 (&lo->lo_mutex){+.+.}-{3:3}:
__mutex_lock+0xba/0x7c0
lo_open+0x28/0x60 [loop]
blkdev_get_whole+0x28/0xf0
blkdev_get_by_dev.part.0+0x168/0x3c0
blkdev_open+0xd2/0xe0
do_dentry_open+0x163/0x3a0
path_openat+0x74d/0xa40
do_filp_open+0x9c/0x140
do_sys_openat2+0xb1/0x170
__x64_sys_openat+0x54/0x90
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
-> #4 (&disk->open_mutex){+.+.}-{3:3}:
__mutex_lock+0xba/0x7c0
blkdev_get_by_dev.part.0+0xd1/0x3c0
blkdev_get_by_path+0xc0/0xd0
btrfs_scan_one_device+0x52/0x1f0 [btrfs]
btrfs_control_ioctl+0xac/0x170 [btrfs]
__x64_sys_ioctl+0x83/0xb0
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
-> #3 (uuid_mutex){+.+.}-{3:3}:
__mutex_lock+0xba/0x7c0
btrfs_rm_device+0x48/0x6a0 [btrfs]
btrfs_ioctl+0x2d1c/0x3110 [btrfs]
__x64_sys_ioctl+0x83/0xb0
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
-> #2 (sb_writers#11){.+.+}-{0:0}:
lo_write_bvec+0x112/0x290 [loop]
loop_process_work+0x25f/0xcb0 [loop]
process_one_work+0x28f/0x5d0
worker_thread+0x55/0x3c0
kthread+0x140/0x170
ret_from_fork+0x22/0x30
-> #1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}:
process_one_work+0x266/0x5d0
worker_thread+0x55/0x3c0
kthread+0x140/0x170
ret_from_fork+0x22/0x30
-> #0 ((wq_completion)loop0){+.+.}-{0:0}:
__lock_acquire+0x1130/0x1dc0
lock_acquire+0xf5/0x320
flush_workqueue+0xae/0x600
drain_workqueue+0xa0/0x110
destroy_workqueue+0x36/0x250
__loop_clr_fd+0x9a/0x650 [loop]
lo_ioctl+0x29d/0x780 [loop]
block_ioctl+0x3f/0x50
__x64_sys_ioctl+0x83/0xb0
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
other info that might help us debug this:
Chain exists of:
(wq_completion)loop0 --> &disk->open_mutex --> &lo->lo_mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&lo->lo_mutex);
lock(&disk->open_mutex);
lock(&lo->lo_mutex);
lock((wq_completion)loop0);
*** DEADLOCK ***
1 lock held by losetup/156417:
#0: ffff9c7647395468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x650 [loop]
stack backtrace:
CPU: 8 PID: 156417 Comm: losetup Not tainted 5.14.0-rc2-custom+ #34
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
Call Trace:
dump_stack_lvl+0x57/0x72
check_noncircular+0x10a/0x120
__lock_acquire+0x1130/0x1dc0
lock_acquire+0xf5/0x320
? flush_workqueue+0x84/0x600
flush_workqueue+0xae/0x600
? flush_workqueue+0x84/0x600
drain_workqueue+0xa0/0x110
destroy_workqueue+0x36/0x250
__loop_clr_fd+0x9a/0x650 [loop]
lo_ioctl+0x29d/0x780 [loop]
? __lock_acquire+0x3a0/0x1dc0
? update_dl_rq_load_avg+0x152/0x360
? lock_is_held_type+0xa5/0x120
? find_held_lock.constprop.0+0x2b/0x80
block_ioctl+0x3f/0x50
__x64_sys_ioctl+0x83/0xb0
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f645884de6b
Usually the uuid_mutex exists to protect the fs_devices that map
together all of the devices that match a specific uuid. In rm_device
we're messing with the uuid of a device, so it makes sense to protect
that here.
However in doing that it pulls in a whole host of lockdep dependencies,
as we call mnt_may_write() on the sb before we grab the uuid_mutex, thus
we end up with the dependency chain under the uuid_mutex being added
under the normal sb write dependency chain, which causes problems with
loop devices.
We don't need the uuid mutex here however. If we call
btrfs_scan_one_device() before we scratch the super block we will find
the fs_devices and not find the device itself and return EBUSY because
the fs_devices is open. If we call it after the scratch happens it will
not appear to be a valid btrfs file system.
We do not need to worry about other fs_devices modifying operations here
because we're protected by the exclusive operations locking.
So drop the uuid_mutex here in order to fix the lockdep splat.
A more detailed explanation from the discussion:
We are worried about rm and scan racing with each other, before this
change we'll zero the device out under the UUID mutex so when scan does
run it'll make sure that it can go through the whole device scan thing
without rm messing with us.
We aren't worried if the scratch happens first, because the result is we
don't think this is a btrfs device and we bail out.
The only case we are concerned with is we scratch _after_ scan is able
to read the superblock and gets a seemingly valid super block, so lets
consider this case.
Scan will call device_list_add() with the device we're removing. We'll
call find_fsid_with_metadata_uuid() and get our fs_devices for this
UUID. At this point we lock the fs_devices->device_list_mutex. This is
what protects us in this case, but we have two cases here.
1. We aren't to the device removal part of the RM. We found our device,
and device name matches our path, we go down and we set total_devices
to our super number of devices, which doesn't affect anything because
we haven't done the remove yet.
2. We are past the device removal part, which is protected by the
device_list_mutex. Scan doesn't find the device, it goes down and
does the
if (fs_devices->opened)
return -EBUSY;
check and we bail out.
Nothing about this situation is ideal, but the lockdep splat is real,
and the fix is safe, tho admittedly a bit scary looking.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ copy more from the discussion ]
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>
The structure btrfs_bio is used by two different sites:
- bio->bi_private for mirror based profiles
For those profiles (SINGLE/DUP/RAID1*/RAID10), this structures records
how many mirrors are still pending, and save the original endio
function of the bio.
- RAID56 code
In that case, RAID56 only utilize the stripes info, and no long uses
that to trace the pending mirrors.
So btrfs_bio is not always bind to a bio, and contains more info for IO
context, thus renaming it will make the naming less confusing.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
After the first time we log a directory in the current transaction, for
each directory item in a changed leaf of the subvolume tree, we have to
check if we previously logged the item, in order to overwrite it in case
its data changed or skip it in case its data hasn't changed.
Checking if we have logged each item before not only wastes times, but it
also adds lock contention on the log tree. So in order to minimize the
number of times we do such checks, keep track of the offset of the last
key we logged for a directory and, on the next time we log the directory,
skip the checks for any new keys that have an offset greater than the
offset we have previously saved. This is specially effective for index
keys, because the offset for these keys comes from a monotonically
increasing counter.
This patch is part of a patchset comprised of the following 5 patches:
btrfs: remove root argument from btrfs_log_inode() and its callees
btrfs: remove redundant log root assignment from log_dir_items()
btrfs: factor out the copying loop of dir items from log_dir_items()
btrfs: insert items in batches when logging a directory when possible
btrfs: keep track of the last logged keys when logging a directory
This is patch 5/5.
The following test was used on a non-debug kernel to measure the impact
it has on a directory fsync:
$ cat test-dir-fsync.sh
#!/bin/bash
DEV=/dev/nvme0n1
MNT=/mnt/nvme0n1
NUM_NEW_FILES=100000
NUM_FILE_DELETES=1000
mkfs.btrfs -f $DEV
mount -o ssd $DEV $MNT
mkdir $MNT/testdir
for ((i = 1; i <= $NUM_NEW_FILES; i++)); do
echo -n > $MNT/testdir/file_$i
done
# fsync the directory, this will log the new dir items and the inodes
# they point to, because these are new inodes.
start=$(date +%s%N)
xfs_io -c "fsync" $MNT/testdir
end=$(date +%s%N)
dur=$(( (end - start) / 1000000 ))
echo "dir fsync took $dur ms after adding $NUM_NEW_FILES files"
# sync to force transaction commit and wipeout the log.
sync
del_inc=$(( $NUM_NEW_FILES / $NUM_FILE_DELETES ))
for ((i = 1; i <= $NUM_NEW_FILES; i += $del_inc)); do
rm -f $MNT/testdir/file_$i
done
# fsync the directory, this will only log dir items, there are no
# dentries pointing to new inodes.
start=$(date +%s%N)
xfs_io -c "fsync" $MNT/testdir
end=$(date +%s%N)
dur=$(( (end - start) / 1000000 ))
echo "dir fsync took $dur ms after deleting $NUM_FILE_DELETES files"
umount $MNT
Test results with NUM_NEW_FILES set to 100 000 and 1 000 000:
**** before patchset, 100 000 files, 1000 deletes ****
dir fsync took 848 ms after adding 100000 files
dir fsync took 175 ms after deleting 1000 files
**** after patchset, 100 000 files, 1000 deletes ****
dir fsync took 758 ms after adding 100000 files (-11.2%)
dir fsync took 63 ms after deleting 1000 files (-94.1%)
**** before patchset, 1 000 000 files, 1000 deletes ****
dir fsync took 9945 ms after adding 1000000 files
dir fsync took 473 ms after deleting 1000 files
**** after patchset, 1 000 000 files, 1000 deletes ****
dir fsync took 8677 ms after adding 1000000 files (-13.6%)
dir fsync took 146 ms after deleting 1000 files (-105.6%)
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When logging a directory, we scan its directory items from the subvolume
tree and then copy one by one into the log tree. This is not efficient
since we generally are able to insert several items in a batch, using a
single btree operation for adding several items at once. The reason we
copy items one by one is that we must check if each item was previously
logged in the current transaction, and if it was we either overwrite it
or skip it in case its content did not change in the subvolume tree (this
can happen only for dir item keys, but not for dir index keys), and doing
such check makes it a bit cumbersome to attempt batch insertions.
However the chances for doing batch insertions are very frequent and
always happen when:
1) Logging the directory for the first time in the current transaction,
as none of the items exist in the log tree yet;
2) Logging new dir index keys, because the offset for new dir index keys
comes from a monotonically increasing counter. This means if we keep
adding dentries to a directory, through creation of new files and
sub-directories or by adding new links or renaming from some other
directory into the one we are logging, all the new dir index keys
have a new offset that is greater than the offset of any previously
logged index keys, so we can insert them in batches into the log tree.
For dir item keys, since their offset depends on the result of an hash
function against the dentry's name, unless the directory is being logged
for the first time in the current transaction, the chances being able to
insert the items in the log using batches is pretty much random and not
predictable, as it depends on the names of the dentries, but still happens
often enough.
So change directory logging to keep track of consecutive directory items
that don't exist yet in the log and batch insert them.
This patch is part of a patchset comprised of the following 5 patches:
btrfs: remove root argument from btrfs_log_inode() and its callees
btrfs: remove redundant log root assignment from log_dir_items()
btrfs: factor out the copying loop of dir items from log_dir_items()
btrfs: insert items in batches when logging a directory when possible
btrfs: keep track of the last logged keys when logging a directory
This is patch 4/5. The change log of the last patch (5/5) has performance
results.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In preparation for the next change, move the loop that processes a leaf
and copies its directory items to the log, into a separate helper
function. This makes the next change simpler and it also helps making
log_dir_items() a bit shorter (specially after the next change).
This patch is part of a patchset comprised of the following 5 patches:
btrfs: remove root argument from btrfs_log_inode() and its callees
btrfs: remove redundant log root assignment from log_dir_items()
btrfs: factor out the copying loop of dir items from log_dir_items()
btrfs: insert items in batches when logging a directory when possible
btrfs: keep track of the last logged keys when logging a directory
This is patch 3/5. The change log of the last patch (5/5) has performance
results.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
At log_dir_items() we are assigning the exact same value to the local
variable 'log', once when it's declared and once again shortly after.
Remove the later assignment as it's pointless.
This patch is part of a patchset comprised of the following 5 patches:
btrfs: remove root argument from btrfs_log_inode() and its callees
btrfs: remove redundant log root assignment from log_dir_items()
btrfs: factor out the copying loop of dir items from log_dir_items()
btrfs: insert items in batches when logging a directory when possible
btrfs: keep track of the last logged keys when logging a directory
This is patch 2/5. The change log of the last patch (5/5) has performance
results.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The root argument passed to btrfs_log_inode() is unncessary, as it is
always the root of the inode we are going to log. This root also gets
unnecessarily propagated to several functions called by btrfs_log_inode(),
and all of them take the inode as an argument as well. So just remove
the root argument from these functions and have them get the root from
the inode where needed.
This patch is part of a patchset comprised of the following 5 patches:
btrfs: remove root argument from btrfs_log_inode() and its callees
btrfs: remove redundant log root assignment from log_dir_items()
btrfs: factor out the copying loop of dir items from log_dir_items()
btrfs: insert items in batches when logging a directory when possible
btrfs: keep track of the last logged keys when logging a directory
This is patch 1/5. The change log of the last patch (5/5) has performance
results.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The statement which decides if an extent allocation on a zoned device is
for the dedicated tree-log block group or not and if we can use the block
group we picked for this allocation is not easy to read but an important
part of the allocator.
Rewrite into an if condition instead of a plain boolean test to make it
stand out more, like the version which tests for the dedicated
data-relocation block group.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In btrfs code we have two functions called setup_extent_mapping, one in
the extent_map code and one in the relocation code. While both are
private to their respective implementation, this can still be confusing
for the reader.
So rename the version in relocation.c to setup_relocation_extent_mapping.
No functional changes.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we use a dedicated block group and regular writes for data
relocation, we can preallocate the space needed for a relocated inode,
just like we do in regular mode.
Essentially this reverts commit 32430c6148 ("btrfs: zoned: enable
relocation on a zoned filesystem") as it is not needed anymore.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Prepare for allowing preallocation for relocation inodes.
Reviewed-by: Naohiro Aota <naohiro.aota@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>
Now that we have a dedicated block group for relocation, we can use
REQ_OP_WRITE instead of REQ_OP_ZONE_APPEND for writing out the data on
relocation.
Reviewed-by: Naohiro Aota <naohiro.aota@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>
Don't allow more than one process to add pages to a relocation inode on
a zoned filesystem, otherwise we cannot guarantee the sequential write
rule once we're filling preallocated extents on a zoned filesystem.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Relocation in a zoned filesystem can fail with a transaction abort with
error -22 (EINVAL). This happens because the relocation code assumes that
the extents we relocated the data to have the same size the source extents
had and ensures this by preallocating the extents.
But in a zoned filesystem we currently can't preallocate the extents as
this would break the sequential write required rule. Therefore it can
happen that the writeback process kicks in while we're still adding pages
to a delalloc range and starts writing out dirty pages.
This then creates destination extents that are smaller than the source
extents, triggering the following safety check in get_new_location():
1034 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1035 ret = -EINVAL;
1036 goto out;
1037 }
Temporarily create a dedicated block group for the relocation process, so
no non-relocation data writes can interfere with the relocation writes.
This is needed that we can switch the relocation process on a zoned
filesystem from the REQ_OP_ZONE_APPEND writing we use for data to a scheme
like in a non-zoned filesystem using REQ_OP_WRITE and preallocation.
Fixes: 32430c6148 ("btrfs: zoned: enable relocation on a zoned filesystem")
Reviewed-by: Naohiro Aota <naohiro.aota@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>
There are several places in our codebase where we check if a root is the
root of the data reloc tree and subsequent patches will introduce more.
Factor out the check into a small helper function instead of open coding
it multiple times.
Reviewed-by: Naohiro Aota <naohiro.aota@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>
Function repair_io_failure() is no longer used out of extent_io.c since
commit 8b9b6f2554 ("btrfs: scrub: cleanup the remaining nodatasum
fixup code"), which removes the last external caller.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When logging a regular file in full sync mode, we are currently committing
its delayed inode item. This is to ensure that we never miss copying the
inode item, with its most up to date data, into the log tree.
However that is not necessary since commit e4545de5b0 ("Btrfs: fix fsync
data loss after append write"), because even if we don't find the leaf
with the inode item when looking for leaves that changed in the current
transaction, we end up logging the inode item later using the in-memory
content. In case we find the leaf containing the inode item, we already
end up using the in-memory inode for filling the inode item in the log
tree, and not the inode item that is in the fs/subvolume tree, as it
might be not up to date (copy_items() -> fill_inode_item()).
So don't commit the delayed inode item, which brings a couple of benefits:
1) Avoid writing the inode item to the fs/subvolume btree, saving time and
reducing lock contention on the btree;
2) In case no other item for the inode was changed, added or deleted in
the same leaf where the inode item is located, we ended up copying
all the items in that leaf to the log tree - it's harmless from a
functional point of view, but it wastes time and log tree space.
This patch is part of a patch set comprised of the following patches:
btrfs: check if a log tree exists at inode_logged()
btrfs: remove no longer needed checks for NULL log context
btrfs: do not log new dentries when logging that a new name exists
btrfs: always update the logged transaction when logging new names
btrfs: avoid expensive search when dropping inode items from log
btrfs: add helper to truncate inode items when logging inode
btrfs: avoid expensive search when truncating inode items from the log
btrfs: avoid search for logged i_size when logging inode if possible
btrfs: avoid attempt to drop extents when logging inode for the first time
btrfs: do not commit delayed inode when logging a file in full sync mode
This is patch 10/10 and the following test results compare a branch with
the whole patch set applied versus a branch without any of the patches
applied.
The following script was used to test dbench with 8 and 16 jobs on a
machine with 12 cores, 64G of RAM, a NVME device and using a non-debug
kernel config (Debian's default):
$ cat test.sh
#!/bin/bash
if [ $# -ne 1 ]; then
echo "Use $0 NUM_JOBS"
exit 1
fi
NUM_JOBS=$1
DEV=/dev/nvme0n1
MNT=/mnt/nvme0n1
MOUNT_OPTIONS="-o ssd"
MKFS_OPTIONS="-m single -d single"
echo "performance" | \
tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
mkfs.btrfs -f $MKFS_OPTIONS $DEV
mount $MOUNT_OPTIONS $DEV $MNT
dbench -D $MNT -t 120 $NUM_JOBS
umount $MNT
The results were the following:
8 jobs, before patchset:
Operation Count AvgLat MaxLat
----------------------------------------
NTCreateX 4113896 0.009 238.665
Close 3021699 0.001 0.590
Rename 174215 0.082 238.733
Unlink 830977 0.049 238.642
Deltree 96 2.232 8.022
Mkdir 48 0.003 0.005
Qpathinfo 3729013 0.005 2.672
Qfileinfo 653206 0.001 0.152
Qfsinfo 683866 0.002 0.526
Sfileinfo 335055 0.004 1.571
Find 1441800 0.016 4.288
WriteX 2049644 0.010 3.982
ReadX 6449786 0.003 0.969
LockX 13400 0.002 0.043
UnlockX 13400 0.001 0.075
Flush 288349 2.521 245.516
Throughput 1075.73 MB/sec 8 clients 8 procs max_latency=245.520 ms
8 jobs, after patchset:
Operation Count AvgLat MaxLat
----------------------------------------
NTCreateX 4154282 0.009 156.675
Close 3051450 0.001 0.843
Rename 175912 0.072 4.444
Unlink 839067 0.048 66.050
Deltree 96 2.131 5.979
Mkdir 48 0.002 0.004
Qpathinfo 3765575 0.005 3.079
Qfileinfo 659582 0.001 0.099
Qfsinfo 690474 0.002 0.155
Sfileinfo 338366 0.004 1.419
Find 1455816 0.016 3.423
WriteX 2069538 0.010 4.328
ReadX 6512429 0.003 0.840
LockX 13530 0.002 0.078
UnlockX 13530 0.001 0.051
Flush 291158 2.500 163.468
Throughput 1105.45 MB/sec 8 clients 8 procs max_latency=163.474 ms
+2.7% throughput, -40.1% max latency
16 jobs, before patchset:
Operation Count AvgLat MaxLat
----------------------------------------
NTCreateX 5457602 0.033 337.098
Close 4008979 0.002 2.018
Rename 231051 0.323 254.054
Unlink 1102209 0.202 337.243
Deltree 160 6.521 31.720
Mkdir 80 0.003 0.007
Qpathinfo 4946147 0.014 6.988
Qfileinfo 867440 0.001 1.642
Qfsinfo 907081 0.003 1.821
Sfileinfo 444433 0.005 2.053
Find 1912506 0.067 7.854
WriteX 2724852 0.018 7.428
ReadX 8553883 0.003 2.059
LockX 17770 0.003 0.350
UnlockX 17770 0.002 0.627
Flush 382533 2.810 353.691
Throughput 1413.09 MB/sec 16 clients 16 procs max_latency=353.696 ms
16 jobs, after patchset:
Operation Count AvgLat MaxLat
----------------------------------------
NTCreateX 5393156 0.034 303.181
Close 3961986 0.002 1.502
Rename 228359 0.320 253.379
Unlink 1088920 0.206 303.409
Deltree 160 6.419 30.088
Mkdir 80 0.003 0.004
Qpathinfo 4887967 0.015 7.722
Qfileinfo 857408 0.001 1.651
Qfsinfo 896343 0.002 2.147
Sfileinfo 439317 0.005 4.298
Find 1890018 0.073 8.347
WriteX 2693356 0.018 6.373
ReadX 8453485 0.003 3.836
LockX 17562 0.003 0.486
UnlockX 17562 0.002 0.635
Flush 378023 2.802 315.904
Throughput 1454.46 MB/sec 16 clients 16 procs max_latency=315.910 ms
+2.9% throughput, -11.3% max latency
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When logging an extent, in the fast fsync path, we always attempt do drop
or trim any existing extents with a range that match or overlap the range
of the extent we are about to log. We do that through a call to
btrfs_drop_extents().
However this is not needed when we are logging the inode for the first
time in the current transaction, since we have no inode items of the
inode in the log tree. Calling btrfs_drop_extents() does a deletion search
on the log tree, which is expensive when we have concurrent tasks
accessing the log tree because a deletion search always acquires a write
lock on the extent buffers at levels 2, 1 and 0, adding significant lock
contention, specially taking into account the height of a log tree rarely
(if ever) goes beyond 2 or 3, due to its short life.
So skip the call to btrfs_drop_extents() when the inode was not previously
logged in the current transaction.
This patch is part of a patch set comprised of the following patches:
btrfs: check if a log tree exists at inode_logged()
btrfs: remove no longer needed checks for NULL log context
btrfs: do not log new dentries when logging that a new name exists
btrfs: always update the logged transaction when logging new names
btrfs: avoid expensive search when dropping inode items from log
btrfs: add helper to truncate inode items when logging inode
btrfs: avoid expensive search when truncating inode items from the log
btrfs: avoid search for logged i_size when logging inode if possible
btrfs: avoid attempt to drop extents when logging inode for the first time
btrfs: do not commit delayed inode when logging a file in full sync mode
This is patch 9/10 and test results are listed in the change log of the
last patch in the set.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If we are logging that an inode exists and the inode was not logged
before, we can avoid searching in the log tree for the inode item since we
know it does not exists. That wastes time and adds more lock contention on
the extent buffers of the log tree when there are other tasks that are
logging other inodes.
This patch is part of a patch set comprised of the following patches:
btrfs: check if a log tree exists at inode_logged()
btrfs: remove no longer needed checks for NULL log context
btrfs: do not log new dentries when logging that a new name exists
btrfs: always update the logged transaction when logging new names
btrfs: avoid expensive search when dropping inode items from log
btrfs: add helper to truncate inode items when logging inode
btrfs: avoid expensive search when truncating inode items from the log
btrfs: avoid search for logged i_size when logging inode if possible
btrfs: avoid attempt to drop extents when logging inode for the first time
btrfs: do not commit delayed inode when logging a file in full sync mode
This is patch 8/10 and test results are listed in the change log of the
last patch in the set.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Whenever we are logging a file inode in full sync mode we call
btrfs_truncate_inode_items() to delete items of the inode we may have
previously logged.
That results in doing a btree search for deletion, which is expensive
because it always acquires write locks for extent buffers at levels 2, 1
and 0, and it balances any node that is less than half full. Acquiring
the write locks can block the task if the extent buffers are already
locked by another task or block other tasks attempting to lock them,
which is specially bad in case of log trees since they are small due to
their short life, with a root node at a level typically not greater than
level 2.
If we know that we are logging the inode for the first time in the current
transaction, we can skip the call to btrfs_truncate_inode_items(), avoiding
the deletion search. This change does that.
This patch is part of a patch set comprised of the following patches:
btrfs: check if a log tree exists at inode_logged()
btrfs: remove no longer needed checks for NULL log context
btrfs: do not log new dentries when logging that a new name exists
btrfs: always update the logged transaction when logging new names
btrfs: avoid expensive search when dropping inode items from log
btrfs: add helper to truncate inode items when logging inode
btrfs: avoid expensive search when truncating inode items from the log
btrfs: avoid search for logged i_size when logging inode if possible
btrfs: avoid attempt to drop extents when logging inode for the first time
btrfs: do not commit delayed inode when logging a file in full sync mode
This is patch 7/10 and test results are listed in the change log of the
last patch in the set.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Move the call to btrfs_truncate_inode_items(), and the surrounding retry
loop, into a local helper function. This avoids some repetition and avoids
making the next change a bit awkward due to a bit of too much indentation.
This patch is part of a patch set comprised of the following patches:
btrfs: check if a log tree exists at inode_logged()
btrfs: remove no longer needed checks for NULL log context
btrfs: do not log new dentries when logging that a new name exists
btrfs: always update the logged transaction when logging new names
btrfs: avoid expensive search when dropping inode items from log
btrfs: add helper to truncate inode items when logging inode
btrfs: avoid expensive search when truncating inode items from the log
btrfs: avoid search for logged i_size when logging inode if possible
btrfs: avoid attempt to drop extents when logging inode for the first time
btrfs: do not commit delayed inode when logging a file in full sync mode
This is patch 6/10 and test results are listed in the change log of the
last patch in the set.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Whenever we are logging a directory inode, logging that an inode exists or
logging an inode that has changes in its references or xattrs, we attempt
to delete items of this inode we may have previously logged (through calls
to drop_objectid_items()).
That attempt does a btree search for deletion, which is expensive because
it always acquires write locks for extent buffers at levels 2, 1 and 0,
and it balances any node that is less than half full. Acquiring the write
locks can block the task if the extent buffers are already locked or block
other tasks attempting to lock them, which is specially bad in case of log
trees since they are small due to their short life, with a root node at a
level typically not greater than level 2.
If we know that we are logging the inode for the first time in the current
transaction, we can skip the search. This change does that.
This patch is part of a patch set comprised of the following patches:
btrfs: check if a log tree exists at inode_logged()
btrfs: remove no longer needed checks for NULL log context
btrfs: do not log new dentries when logging that a new name exists
btrfs: always update the logged transaction when logging new names
btrfs: avoid expensive search when dropping inode items from log
btrfs: add helper to truncate inode items when logging inode
btrfs: avoid expensive search when truncating inode items from the log
btrfs: avoid search for logged i_size when logging inode if possible
btrfs: avoid attempt to drop extents when logging inode for the first time
btrfs: do not commit delayed inode when logging a file in full sync mode
This is patch 5/10 and test results are listed in the change log of the
last patch in the set.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When we are logging a new name for an inode, due to a link or rename
operation, if the inode has ancestor inodes that are new, created in the
current transaction, we need to log that these inodes exist. To ensure
that a subsequent explicit fsync on one of these ancestor inodes does
sync the log, we don't set the logged_trans field of these inodes.
This was done in commit 75b463d2b4 ("btrfs: do not commit logs and
transactions during link and rename operations"), to avoid syncing a
log after a rename or link operation.
In order to allow for future changes to do some optimizations, change
this behaviour to always update the logged_trans of any logged inode
and don't update the last_log_commit of the inode if we are logging
that it exists. This accomplishes that same objective with simpler
logic, allowing for some optimizations in the next patches.
So just do that simplification.
This patch is part of a patch set comprised of the following patches:
btrfs: check if a log tree exists at inode_logged()
btrfs: remove no longer needed checks for NULL log context
btrfs: do not log new dentries when logging that a new name exists
btrfs: always update the logged transaction when logging new names
btrfs: avoid expensive search when dropping inode items from log
btrfs: add helper to truncate inode items when logging inode
btrfs: avoid expensive search when truncating inode items from the log
btrfs: avoid search for logged i_size when logging inode if possible
btrfs: avoid attempt to drop extents when logging inode for the first time
btrfs: do not commit delayed inode when logging a file in full sync mode
This is patch 4/10 and test results are listed in the change log of the
last patch in the set.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When logging a new name for an inode, due to a link or rename operation,
we don't need to log all new dentries of the parent directories and their
subdirectories. We only want to log the names of the inode and that any
new parent directories exist. So in this case don't trigger logging of
the new dentries, that is only need when doing an explicit fsync on a
directory or on a file which requires logging its parent directories.
This avoids unnecessary work and reduces contention on the extent buffers
of a log tree.
This patch is part of a patch set comprised of the following patches:
btrfs: check if a log tree exists at inode_logged()
btrfs: remove no longer needed checks for NULL log context
btrfs: do not log new dentries when logging that a new name exists
btrfs: always update the logged transaction when logging new names
btrfs: avoid expensive search when dropping inode items from log
btrfs: add helper to truncate inode items when logging inode
btrfs: avoid expensive search when truncating inode items from the log
btrfs: avoid search for logged i_size when logging inode if possible
btrfs: avoid attempt to drop extents when logging inode for the first time
btrfs: do not commit delayed inode when logging a file in full sync mode
This is patch 3/10 and test results are listed in the change log of the
last patch in the set.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since commit 75b463d2b4 ("btrfs: do not commit logs and transactions
during link and rename operations"), we always pass a non-NULL log context
to btrfs_log_inode_parent() and therefore to all the functions that it
calls. So remove the checks we have all over the place that test for a
NULL log context, making the code shorter and easier to read, as well as
reducing the size of the generated code.
This patch is part of a patch set comprised of the following patches:
btrfs: check if a log tree exists at inode_logged()
btrfs: remove no longer needed checks for NULL log context
btrfs: do not log new dentries when logging that a new name exists
btrfs: always update the logged transaction when logging new names
btrfs: avoid expensive search when dropping inode items from log
btrfs: add helper to truncate inode items when logging inode
btrfs: avoid expensive search when truncating inode items from the log
btrfs: avoid search for logged i_size when logging inode if possible
btrfs: avoid attempt to drop extents when logging inode for the first time
btrfs: do not commit delayed inode when logging a file in full sync mode
This is patch 2/10 and test results are listed in the change log of the
last patch in the set.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In case an inode was never logged since it was loaded from disk and was
modified in the current transaction (its ->last_trans matches the ID of
the current transaction), inode_logged() returns true even if there's no
existing log tree. In this case we can simply check if a log tree exists
and return false if it does not. This avoids a caller of inode_logged()
doing some unnecessary, but harmless, work.
For btrfs_log_new_name() it avoids it logging an inode in case it was
never logged since it was loaded from disk and there is currently no log
tree for the inode's root. For the remaining callers of inode_logged(),
btrfs_del_dir_entries_in_log() and btrfs_del_inode_ref_in_log(), it has
no effect since they already check if a log tree exists through their
calls to join_running_log_trans().
So just add a check to inode_logged() to verify if a log tree exists, and
return false if it does not.
This patch is part of a patch set comprised of the following patches:
btrfs: check if a log tree exists at inode_logged()
btrfs: remove no longer needed checks for NULL log context
btrfs: do not log new dentries when logging that a new name exists
btrfs: always update the logged transaction when logging new names
btrfs: avoid expensive search when dropping inode items from log
btrfs: add helper to truncate inode items when logging inode
btrfs: avoid expensive search when truncating inode items from the log
btrfs: avoid search for logged i_size when logging inode if possible
btrfs: avoid attempt to drop extents when logging inode for the first time
btrfs: do not commit delayed inode when logging a file in full sync mode
This is patch 1/10 and test results are listed in the change log of the
last patch in the set.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There were few lockdep warnings because btrfs_show_devname() was using
device_list_mutex as recorded in the commits:
0ccd05285e ("btrfs: fix a possible umount deadlock")
779bf3fefa ("btrfs: fix lock dep warning, move scratch dev out of device_list_mutex and uuid_mutex")
And finally, commit 88c14590cd ("btrfs: use RCU in btrfs_show_devname
for device list traversal") removed the device_list_mutex from
btrfs_show_devname for performance reasons.
This patch removes a stale comment about the function
btrfs_show_devname and device_list_mutex.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The test case btrfs/238 reports the warning below:
WARNING: CPU: 3 PID: 481 at fs/btrfs/super.c:2509 btrfs_show_devname+0x104/0x1e8 [btrfs]
CPU: 2 PID: 1 Comm: systemd Tainted: G W O 5.14.0-rc1-custom #72
Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
Call trace:
btrfs_show_devname+0x108/0x1b4 [btrfs]
show_mountinfo+0x234/0x2c4
m_show+0x28/0x34
seq_read_iter+0x12c/0x3c4
vfs_read+0x29c/0x2c8
ksys_read+0x80/0xec
__arm64_sys_read+0x28/0x34
invoke_syscall+0x50/0xf8
do_el0_svc+0x88/0x138
el0_svc+0x2c/0x8c
el0t_64_sync_handler+0x84/0xe4
el0t_64_sync+0x198/0x19c
Reason:
While btrfs_prepare_sprout() moves the fs_devices::devices into
fs_devices::seed_list, the btrfs_show_devname() searches for the devices
and found none, leading to the warning as in above.
Fix:
latest_dev is updated according to the changes to the device list.
That means we could use the latest_dev->name to show the device name in
/proc/self/mounts, the pointer will be always valid as it's assigned
before the device is deleted from the list in remove or replace.
The RCU protection is sufficient as the device structure is freed after
synchronization.
Reported-by: Su Yue <l@damenly.su>
Tested-by: Su Yue <l@damenly.su>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In preparation to fix a bug in btrfs_show_devname().
Convert fs_devices::latest_bdev type from struct block_device to struct
btrfs_device and, rename the member to fs_devices::latest_dev.
So that btrfs_show_devname() can use fs_devices::latest_dev::name.
Tested-by: Su Yue <l@damenly.su>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We will no longer write to a relocating block group. So, we can finish it
now.
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If we have written to the zone capacity, the device automatically
deactivates the zone. Sync up block group side (the active BG list and
zone_is_active flag) with it.
We need to do it both on data BGs and metadata BGs. On data side, we add a
hook to btrfs_finish_ordered_io(). On metadata side, we use
end_extent_buffer_writeback().
To reduce excess lookup of a block group, we mark the last extent buffer in
a block group with EXTENT_BUFFER_ZONE_FINISH flag. This cannot be done for
data (ordered_extent), because the address may change due to
REQ_OP_ZONE_APPEND.
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The current extent allocator tries to allocate a new block group when the
existing block groups do not have enough space. On a ZNS device, a new
block group means a new active zone. If the number of active zones has
already reached the max_active_zones, activating a new zone needs to finish
an existing zone, leading to wasting the free space there.
So, instead, it should reuse the existing active block groups as much as
possible when we can't activate any other zones without sacrificing an
already activated block group.
While at it, I converted find_free_extent_update_loop() to check the
found_extent() case early and made the other conditions simpler.
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We are passing too many variables as it is from btrfs_reserve_extent() to
find_free_extent(). The next commit will add min_alloc_size to ffe_ctl, and
that means another pass-through argument. Take this opportunity to move
ffe_ctl one level up and drop the redundant arguments.
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Activate new block group at btrfs_make_block_group(). We do not check the
return value. If failed, we can try again later at the actual extent
allocation phase.
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Activate a block group when trying to allocate an extent from it. We check
read-only case and no space left case before trying to activate a block
group not to consume the number of active zones uselessly.
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Load activeness of underlying zones of a block group. When underlying zones
are active, we add the block group to the fs_info->zone_active_bgs list.
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add zone_is_active flag to btrfs_block_group. This flag indicates the
underlying zones are all active. Such zone active block groups are tracked
by fs_info->active_bg_list.
btrfs_dev_{set,clear}_active_zone() take responsibility for the underlying
device part. They set/clear the bitmap to indicate zone activeness and
count the number of zones we can activate left.
btrfs_zone_{activate,finish}() take responsibility for the logical part and
the list management. In addition, btrfs_zone_finish() wait for any writes
on it and send REQ_OP_ZONE_FINISH to the zone.
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We will use a block group's physical location to track active zones and
finish fully written zones in the following commits. Since the zone
activation is done in the extent allocation context which already holding
the tree locks, we can't query the chunk tree for the physical locations.
So, copy the location info into a block group and use it for activation.
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The ZNS specification defines a limit on the number of zones that can be in
the implicit open, explicit open or closed conditions. Any zone with such
condition is defined as an active zone and correspond to any zone that is
being written or that has been only partially written. If the maximum
number of active zones is reached, we must either reset or finish some
active zones before being able to chose other zones for storing data.
Load queue_max_active_zones() and track the number of active zones left on
the device.
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If there is no more space left for a new superblock in a superblock zone,
then it is better to ZONE_FINISH the zone and frees up the active zone
count.
Since btrfs_advance_sb_log() can now issue REQ_OP_ZONE_FINISH, we also need
to convert it to return int for the error case.
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
sb_write_pointer() returns the write position of next superblock. For READ,
we need a previous location. When the pointer is at the head, the previous
one is the last one of the other zone. Calculate the last one's position
from zone capacity.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We cannot write beyond zone capacity. So, we should consider a zone as
"full" when the write pointer goes beyond capacity - the size of super
info.
Also, take this opportunity to replace a subtle duplicated code with a loop
and fix a typo in comment.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
With the introduction of zone capacity, the range [capacity, length] is
always zone unusable. Counting this region as a reclaim target will
cause reclaiming too early. Reclaim block groups based on bytes that can
be usable after resetting.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we introduced capacity in a block group, we need to calculate free
space using the capacity instead of the length. Thus, bytes we account
capacity - alloc_pointer as free, and account bytes [capacity, length] as
zone unusable.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_free_excluded_extents() is not neccessary for
btrfs_calc_zone_unusable() and it makes btrfs_calc_zone_unusable()
difficult to reuse. Move it out and call btrfs_free_excluded_extents()
in proper context.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The ZNS specification introduces the concept of a Zone Capacity. A zone
capacity is an additional per-zone attribute that indicates the number of
usable logical blocks within each zone, starting from the first logical
block of each zone. It is always smaller or equal to the zone size.
With the SINGLE profile, we can set a block group's "capacity" as the same
as the underlying zone's Zone Capacity. We will limit the allocation not
to exceed in a following commit.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
With the new infrastructure which has taken subpage into consideration,
now we should be safe to allow defrag to work for subpage case.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now the old infrastructure can all be removed, defrag
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 defrag_one_cluster() is able to defrag one range well
enough, we only need to do preparation for it, including:
- Clamp and align the defrag range
- Exclude invalid cases
- Proper inode locking
The old infrastructures will not be removed in this patch, as it would
be too noisy to review.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This new helper, defrag_one_cluster(), will defrag one cluster (at most
256K):
- Collect all initial targets
- Kick in readahead when possible
- Call defrag_one_range() on each initial target
With some extra range clamping.
- Update @sectors_defragged parameter
This involves one behavior change, the defragged sectors accounting is
no longer as accurate as old behavior, as the initial targets are not
consistent.
We can have new holes punched inside the initial target, and we will
skip such holes later.
But the defragged sectors accounting doesn't need to be that accurate
anyway, thus I don't want to pass those extra accounting burden into
defrag_one_range().
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A new helper, defrag_one_range(), is introduced to defrag one range.
This function will mostly prepare the needed pages and extent status for
defrag_one_locked_target().
As we can only have a consistent view of extent map with page and extent
bits locked, we need to re-check the range passed in to get a real
target list for defrag_one_locked_target().
Since defrag_collect_targets() will call defrag_lookup_extent() and lock
extent range, we also need to teach those two functions to skip extent
lock. Thus new parameter, @locked, is introduced to skip extent lock if
the caller has already locked the range.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A new helper, defrag_one_locked_target(), introduced to do the real part
of defrag.
The caller needs to ensure both page and extents bits are locked, and no
ordered extent exists for the range, and all writeback is finished.
The core defrag part is pretty straight-forward:
- Reserve space
- Set extent bits to defrag
- Update involved pages to be dirty
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Introduce a helper, defrag_collect_targets(), to collect all possible
targets to be defragged.
This function will not consider things like max_sectors_to_defrag, thus
caller should be responsible to ensure we don't exceed the limit.
This function will be the first stage of later defrag rework.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In cluster_pages_for_defrag(), we have complex code block inside one
for() loop.
The code block is to prepare one page for defrag, this will ensure:
- The page is locked and set up properly.
- No ordered extent exists in the page range.
- The page is uptodate.
This behavior is pretty common and will be reused by later defrag
rework.
So factor out the code into its own helper, defrag_prepare_one_page(),
for later usage, and cleanup the code by a little.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When testing subpage defrag support, I always find some strange inode
nbytes error, after a lot of debugging, it turns out that
defrag_lookup_extent() is using PAGE_SIZE as size for
lookup_extent_mapping().
Since lookup_extent_mapping() is calling __lookup_extent_mapping() with
@strict == 1, this means any extent map smaller than one page will be
ignored, prevent subpage defrag to grab a correct extent map.
There are quite some PAGE_SIZE usage in ioctl.c, but most of them are
correct usages, and can be one of the following cases:
- ioctl structure size check
We want ioctl structure to be contained inside one page.
- real page operations
The remaining cases in defrag_lookup_extent() and
check_defrag_in_cache() will be addressed in this patch.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In function cluster_pages_for_defrag() we have a window where we unlock
page, either start the ordered range or read the content from disk.
When we re-lock the page, we need to make sure it still has the correct
page->private for subpage.
Thus add the extra PagePrivate check here to handle subpage cases
properly.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently btrfs_defrag_file() accepts both "struct inode" and "struct
file" as parameter. We can easily grab "struct inode" from "struct
file" using file_inode() helper.
The reason why we need "struct file" is just to re-use its f_ra.
Change this to pass "struct file_ra_state" parameter, so that it's more
clear what we really want. Since we're here, also add some comments on
the function btrfs_defrag_file().
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_chunk_readonly() checks if the given chunk is writeable. It
returns 1 for readonly, and 0 for writeable. So the return argument type
bool shall suffice instead of the current type int.
Also, rename btrfs_chunk_readonly() to btrfs_chunk_writeable() as we
check if the bg is writeable, and helps to keep the logic at the parent
function simpler to understand.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Fix a warning reported by smatch that ret could be returned without
initialized. The dedupe operations are supposed to to return 0 for a 0
length range but the caller does not pass olen == 0. To keep this
behaviour and also fix the warning initialize ret to 0.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Sidong Yang <realwakka@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently we use u16 bitmap to make 4k sectorsize work for 64K page
size.
But this u16 bitmap is not large enough to contain larger page size like
128K, nor is space efficient for 16K page size.
To handle both cases, here we pack all subpage bitmaps into a larger
bitmap, now btrfs_subpage::bitmaps[] will be the ultimate bitmap for
subpage usage.
Each sub-bitmap will has its start bit number recorded in
btrfs_subpage_info::*_start, and its bitmap length will be recorded in
btrfs_subpage_info::bitmap_nr_bits.
All subpage bitmap operations will be converted from using direct u16
operations to bitmap operations, with above *_start calculated.
For 64K page size with 4K sectorsize, this should not cause much
difference.
While for 16K page size, we will only need 1 unsigned long (u32) to
store all the bitmaps, which saves quite some space.
Furthermore, this allows us to support larger page size like 128K and
258K.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently we use fixed size u16 bitmap for subpage bitmap. This is fine
for 4K sectorsize with 64K page size.
But for 4K sectorsize and larger page size, the bitmap is too small,
while for smaller page size like 16K, u16 bitmaps waste too much space.
Here we introduce a new helper structure, btrfs_subpage_bitmap_info, to
record the proper bitmap size, and where each bitmap should start at.
By this, we can later compact all subpage bitmaps into one u32 bitmap.
This patch is the first step.
Reviewed-by: Nikolay Borisov <nborisov@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 existing calling convention of btrfs_alloc_subpage() is pretty
awful. Change it to a more common pattern by returning struct
btrfs_subpage directly and let the caller to determine if the call
succeeded.
Reviewed-by: Nikolay Borisov <nborisov@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>
There are two call sites of btrfs_alloc_subpage():
- btrfs_attach_subpage()
We have ensured sectorsize is smaller than PAGE_SIZE
- alloc_extent_buffer()
We call btrfs_alloc_subpage() unconditionally.
The alloc_extent_buffer() forces us to check the sectorsize size against
page size inside btrfs_alloc_subpage().
Since the function name, btrfs_alloc_subpage(), already indicates it
should only get called for subpage cases, do the check in
alloc_extent_buffer() and add an ASSERT() in btrfs_alloc_subpage().
Reviewed-by: Nikolay Borisov <nborisov@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>
