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The unsigned type is a recommended practice (CWE-190, CWE-194) for bit
shifts to avoid problems with potential unwanted sign extensions.
Although there are no such cases in btrfs codebase, follow the
recommendation.
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
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All compression algorithms inside btrfs are not supporting large folios
due to the following points:
- btrfs_calc_input_length() is assuming page sized folio
- kmap_local_folio() usages are using offset_in_page()
Prepare them to support large data folios by:
- Add a folio parameter to btrfs_calc_input_length()
And use that folio parameter to calculate the correct length.
Since we're here, also add extra ASSERT()s to make sure the parameter
@cur is inside the folio range.
This affects only zlib and zstd. Lzo compresses at most one block at a
time, thus not affected.
- Use offset_in_folio() to calculate the kmap_local_folio() offset
This affects all 3 algorithms.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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timer_delete[_sync]() replaces del_timer[_sync](). Convert the whole tree
over and remove the historical wrapper inlines.
Conversion was done with coccinelle plus manual fixups where necessary.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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When using offset_in_page() it's clear what it means, we don't need to
store it in the local variable just to use it right away. There's no
change in the generated code, but keeps the declarations smaller.
Signed-off-by: David Sterba <dsterba@suse.com>
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Reduce stack consumption of zstd_compress_folios() by 40 bytes
(10*sizeof(int)) as we can store struct zstd_parameters in the workspace
that is reused for each call.
typedef struct {
ZSTD_compressionParameters cParams;
ZSTD_frameParameters fParams;
} ZSTD_parameters;
typedef struct {
unsigned windowLog;
unsigned chainLog;
unsigned hashLog;
unsigned searchLog;
unsigned minMatch;
unsigned targetLength;
ZSTD_strategy strategy;
} ZSTD_compressionParameters;
typedef struct {
int contentSizeFlag;
int checksumFlag;
int noDictIDFlag;
} ZSTD_frameParameters;
Signed-off-by: David Sterba <dsterba@suse.com>
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Allow using the fast modes (negative compression levels) of zstd as a
mount option.
As per the results, the compression ratio is (expectedly) lower:
for level in {-15..-1} 1 2 3; \
do printf "level %3d\n" $level; \
mount -o compress=zstd:$level /dev/sdb /mnt/test/; \
grep sdb /proc/mounts; \
cp -r /usr/bin /mnt/test/; sync; compsize /mnt/test/bin; \
cp -r /usr/share/doc /mnt/test/; sync; compsize /mnt/test/doc; \
cp enwik9 /mnt/test/; sync; compsize /mnt/test/enwik9; \
cp linux-6.13.tar /mnt/test/; sync; compsize /mnt/test/linux-6.13.tar; \
rm -r /mnt/test/{bin,doc,enwik9,linux-6.13.tar}; \
umount /mnt/test/; \
done |& tee results | \
awk '/^level/{print}/^TOTAL/{print$3"\t"$2" |"}' | paste - - - - -
266M bin | 45M doc | 953M wiki | 1.4G source
=============================+===============+===============+===============+
level -15 180M 67% | 30M 68% | 694M 72% | 598M 40% |
level -14 180M 67% | 30M 67% | 683M 71% | 581M 39% |
level -13 177M 66% | 29M 66% | 671M 70% | 566M 38% |
level -12 174M 65% | 29M 65% | 658M 69% | 548M 37% |
level -11 174M 65% | 28M 64% | 645M 67% | 530M 35% |
level -10 171M 64% | 28M 62% | 631M 66% | 512M 34% |
level -9 165M 62% | 27M 61% | 615M 64% | 493M 33% |
level -8 161M 60% | 27M 59% | 598M 62% | 475M 32% |
level -7 155M 58% | 26M 58% | 582M 61% | 457M 30% |
level -6 151M 56% | 25M 56% | 565M 59% | 437M 29% |
level -5 145M 54% | 24M 55% | 545M 57% | 417M 28% |
level -4 139M 52% | 23M 52% | 520M 54% | 391M 26% |
level -3 135M 50% | 22M 50% | 495M 51% | 369M 24% |
level -2 127M 47% | 22M 48% | 470M 49% | 349M 23% |
level -1 120M 45% | 21M 47% | 452M 47% | 332M 22% |
level 1 110M 41% | 17M 39% | 362M 38% | 290M 19% |
level 2 106M 40% | 17M 38% | 349M 36% | 288M 19% |
level 3 104M 39% | 16M 37% | 340M 35% | 276M 18% |
The samples represent some data sets that can be commonly found and show
approximate compressibility. The fast levels trade off speed for ratio
and are best suitable for highly compressible data.
As can be seen above, comparing the results to the current default zstd
level 3, the negative levels are roughly 2x worse at -15 and the
ratio increases almost linearly with each level.
Signed-off-by: Daniel Vacek <neelx@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
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Make sure we got the right timer struct for the zstd workspace reclaim
work.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Inside zstd_compress_folios(), after exhausted one input page, we need
to switch to the next page as input.
However when counting the total input bytes (@tot_in), we always increase
it by PAGE_SIZE.
For the following case, it can cause incorrect value:
0 32K 64K 96K
| |///////////||///////////|
After compressing range [32K, 64K), we switch to the next page, and
increasing @tot_in by 64K, while we only read 32K.
This will cause the @total_in to return a value larger than the input
length.
Fix it by only increase @tot_in by the input size.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The old page API is being gradually replaced and converted to use folio
to improve code readability and avoid repeated conversion between page
and folio. And memcpy_to_page() can be replaced with memcpy_to_folio().
But there is no memzero_folio(), but it can be replaced equivalently by
folio_zero_range().
Signed-off-by: Li Zetao <lizetao1@huawei.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Currently btrfs compression path is not really subpage compatible, every
thing is still done in page unit.
That's fine for regular sector size and subpage routine. As even for
subpage routine compression is only enabled if the whole range is page
aligned, so reading the page cache in page unit is totally fine.
However in preparation for the future subpage perfect compression
support, we need to change the compression routine to properly handle a
subpage range.
This patch would prepare both zlib and zstd to only read the subpage
range for compression.
Lzo is already doing subpage aware read, as lzo's on-disk format is
already sectorsize dependent.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Add more verbose and specific messages to all main error points in
compression code for all algorithms. Currently there's no way to know
which inode is affected or where in the data errors happened.
The messages follow a common format:
- what happened
- error code if relevant
- root and inode
- additional data like offsets or lengths
There's no helper for the messages as they differ in some details and
that would be cumbersome to generalize to a single function. As all the
errors are "almost never happens" there are the unlikely annotations
done as compression is hot path.
Signed-off-by: David Sterba <dsterba@suse.com>
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For both compression and decompression paths, we always require a
"struct page **pages" and "unsigned long nr_pages", this involves quite
some part of the btrfs compression paths:
- All the compression entry points
- compressed_bio structure
This affects both compression and decompression.
- async_extent structure
Unfortunately with all those involved parts, there is no good way to
split the conversion into smaller patches while still passing compiling.
So do this in one big conversion in one go.
Please note this is direct page->folio conversion, no change on the page
sized folio requirement yet.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ minor style fixups ]
Signed-off-by: David Sterba <dsterba@suse.com>
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Currently we have two wrappers to allocate and free a page for
compression usage:
- btrfs_alloc_compr_page()
- btrfs_free_compr_page()
The allocator would try to grab a page from the pool, and only allocate
a new page if the pool is empty.
The reclaimer would check if the pool is full, and if not full it would
put the page into the pool.
This patch converts both helpers to use folio interfaces, and allowing
further conversion of compression path to folios.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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For all the supported compression algorithms, the compression path would
always need to grab the page cache, then do the compression.
Normally we would get a page reference without any problem, since the
write path should have already locked the pages in the write range.
For the sake of error handling, we should handle the page cache miss
case.
Adds a common wrapper, btrfs_compress_find_get_page(), which calls
find_get_page(), and do the error handling along with an error message.
Callers inside compression path would only need to call
btrfs_compress_find_get_page(), and error out if it returned any error.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Note: this is a fixed version that was previously reverted as
e01a83e12604 ("Revert "btrfs: zstd: fix and simplify the inline extent
decompression""), with fixed parameters to memzero_page().
[BUG]
If we have a filesystem with 4k sectorsize, and an inlined compressed
extent created like this:
item 4 key (257 INODE_ITEM 0) itemoff 15863 itemsize 160
generation 8 transid 8 size 4096 nbytes 4096
block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0
sequence 1 flags 0x0(none)
item 5 key (257 INODE_REF 256) itemoff 15839 itemsize 24
index 2 namelen 14 name: source_inlined
item 6 key (257 EXTENT_DATA 0) itemoff 15770 itemsize 69
generation 8 type 0 (inline)
inline extent data size 48 ram_bytes 4096 compression 3 (zstd)
Then trying to reflink that extent in an aarch64 system with 64K page
size, the reflink would just fail:
# xfs_io -f -c "reflink $mnt/source_inlined 0 60k 4k" $mnt/dest
XFS_IOC_CLONE_RANGE: Input/output error
[CAUSE]
In zstd_decompress(), we didn't treat @start_byte as just a page offset,
but also use it as an indicator on whether we should error out, without
any proper explanation (this is copied from other decompression code).
In reality, for subpage cases, although @start_byte can be non-zero,
we should never switch input/output buffer nor error out, since the whole
input/output buffer should never exceed one sector, thus we should not
need to do any buffer switch.
Thus the current code using @start_byte as a condition to switch
input/output buffer or finish the decompression is completely incorrect.
[FIX]
The fix involves several modification:
- Rename @start_byte to @dest_pgoff to properly express its meaning
- Use @sectorsize other than PAGE_SIZE to properly initialize the
output buffer size
- Use correct destination offset inside the destination page
- Simplify the main loop
Since the input/output buffer should never switch, we only need one
zstd_decompress_stream() call.
- Consider early end as an error
After the fix, even on 64K page sized aarch64, above reflink now
works as expected:
# xfs_io -f -c "reflink $mnt/source_inlined 0 60k 4k" $mnt/dest
linked 4096/4096 bytes at offset 61440
And results the correct file layout:
item 9 key (258 INODE_ITEM 0) itemoff 15542 itemsize 160
generation 10 transid 10 size 65536 nbytes 4096
block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0
sequence 1 flags 0x0(none)
item 10 key (258 INODE_REF 256) itemoff 15528 itemsize 14
index 3 namelen 4 name: dest
item 11 key (258 XATTR_ITEM 3817753667) itemoff 15445 itemsize 83
location key (0 UNKNOWN.0 0) type XATTR
transid 10 data_len 37 name_len 16
name: security.selinux
data unconfined_u:object_r:unlabeled_t:s0
item 12 key (258 EXTENT_DATA 61440) itemoff 15392 itemsize 53
generation 10 type 1 (regular)
extent data disk byte 13631488 nr 4096
extent data offset 0 nr 4096 ram 4096
extent compression 0 (none)
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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With help of neovim, LSP and clangd we can identify header files that
are not actually needed to be included in the .c files. This is focused
only on removal (with minor fixups), further cleanups are possible but
will require doing the header files properly with forward declarations,
minimized includes and include-what-you-use care.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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This reverts commit 1e7f6def8b2370ecefb54b3c8f390ff894b0c51b.
It causes my machine to not even boot, and Klara Modin reports that the
cause is that small zstd-compressed files return garbage when read.
Reported-by: Klara Modin <klarasmodin@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/CABq1_vj4GpUeZpVG49OHCo-3sdbe2-2ROcu_xDvUG-6-5zPRXg@mail.gmail.com/
Reported-and-bisected-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: David Sterba <dsterba@suse.com>
Cc: Qu Wenruo <wqu@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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[BUG]
If we have a filesystem with 4k sectorsize, and an inlined compressed
extent created like this:
item 4 key (257 INODE_ITEM 0) itemoff 15863 itemsize 160
generation 8 transid 8 size 4096 nbytes 4096
block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0
sequence 1 flags 0x0(none)
item 5 key (257 INODE_REF 256) itemoff 15839 itemsize 24
index 2 namelen 14 name: source_inlined
item 6 key (257 EXTENT_DATA 0) itemoff 15770 itemsize 69
generation 8 type 0 (inline)
inline extent data size 48 ram_bytes 4096 compression 3 (zstd)
Then trying to reflink that extent in an aarch64 system with 64K page
size, the reflink would just fail:
# xfs_io -f -c "reflink $mnt/source_inlined 0 60k 4k" $mnt/dest
XFS_IOC_CLONE_RANGE: Input/output error
[CAUSE]
In zstd_decompress(), we didn't treat @start_byte as just a page offset,
but also use it as an indicator on whether we should error out, without
any proper explanation (this is copied from other decompression code).
In reality, for subpage cases, although @start_byte can be non-zero,
we should never switch input/output buffer nor error out, since the whole
input/output buffer should never exceed one sector, thus we should not
need to do any buffer switch.
Thus the current code using @start_byte as a condition to switch
input/output buffer or finish the decompression is completely incorrect.
[FIX]
The fix involves several modification:
- Rename @start_byte to @dest_pgoff to properly express its meaning
- Use @sectorsize other than PAGE_SIZE to properly initialize the
output buffer size
- Use correct destination offset inside the destination page
- Simplify the main loop
Since the input/output buffer should never switch, we only need one
zstd_decompress_stream() call.
- Consider early end as an error
After the fix, even on 64K page sized aarch64, above reflink now
works as expected:
# xfs_io -f -c "reflink $mnt/source_inlined 0 60k 4k" $mnt/dest
linked 4096/4096 bytes at offset 61440
And results the correct file layout:
item 9 key (258 INODE_ITEM 0) itemoff 15542 itemsize 160
generation 10 transid 10 size 65536 nbytes 4096
block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0
sequence 1 flags 0x0(none)
item 10 key (258 INODE_REF 256) itemoff 15528 itemsize 14
index 3 namelen 4 name: dest
item 11 key (258 XATTR_ITEM 3817753667) itemoff 15445 itemsize 83
location key (0 UNKNOWN.0 0) type XATTR
transid 10 data_len 37 name_len 16
name: security.selinux
data unconfined_u:object_r:unlabeled_t:s0
item 12 key (258 EXTENT_DATA 61440) itemoff 15392 itemsize 53
generation 10 type 1 (regular)
extent data disk byte 13631488 nr 4096
extent data offset 0 nr 4096 ram 4096
extent compression 0 (none)
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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This is a preparation for managing compression pages in a cache-like
manner, instead of asking the allocator each time. The common allocation
and free wrappers are introduced and are functionally equivalent to the
current code.
The freeing helpers need to be carefully placed where the last reference
is dropped. This is either after directly allocating (error handling)
or when there are no other users of the pages (after copying the contents).
It's safe to not use the helper and use put_page() that will handle the
reference count. Not using the helper means there's lower number of
pages that could be reused without passing them back to allocator.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Function name in the comment does not bring much value to code not
exposed as API and we don't stick to the kdoc format anymore. Update
formatting of parameter descriptions.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The workspaces for compression are typically much larger than a page and
for high zstd levels in the range of megabytes. There's a fallback to
vmalloc but this can still fail (see the report).
Some of the workspaces are preallocated at module load time so we have a
safe fallback, otherwise when a new workspace is needed it's allocated
but if this fails then the process waits. Which means the warning is
only causing noise and we can use the GFP flag to disable it.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=217466
Signed-off-by: David Sterba <dsterba@suse.com>
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All algorithms have to fill the remainder of the orig_bio with zeroes,
so do it in common code.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
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The input buffers passed down to compression must never be changed,
switch type to u8 as it's a raw byte buffer and use const.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Update, reformat or reword function comments. This also removes the kdoc
marker so we don't get reports when the function name is missing.
Changes made:
- remove kdoc markers
- reformat the brief description to be a proper sentence
- reword to imperative voice
- align parameter list
- fix typos
Signed-off-by: David Sterba <dsterba@suse.com>
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The use of kmap() is being deprecated in favor of kmap_local_page(). With
kmap_local_page(), the mapping is per thread, CPU local and not globally
visible.
Therefore, use kmap_local_page() / kunmap_local() in zstd.c because in this
file the mappings are per thread and are not visible in other contexts. In
the meanwhile use plain page_address() on output pages allocated with
the GFP_NOFS flag instead of calling kmap*() on them (since they are
always allocated from ZONE_NORMAL).
Tested with xfstests on QEMU + KVM 32 bits VM with 4GB of RAM, booting a
kernel with HIGHMEM64G enabled.
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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This is an optimization for fix fee13fe96529 ("btrfs: correct zstd
workspace manager lock to use spin_lock_bh()")
The critical region for wsm.lock is only accessed by the process context and
the softirq context.
Because in the soft interrupt, the critical section will not be
preempted by the soft interrupt again, there is no need to call
spin_lock_bh(&wsm.lock) to turn off the soft interrupt,
spin_lock(&wsm.lock) is enough for this situation.
Signed-off-by: Schspa Shi <schspa@gmail.com>
[ minor comment update ]
Signed-off-by: David Sterba <dsterba@suse.com>
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This patch:
- Moves `include/linux/zstd.h` -> `include/linux/zstd_lib.h`
- Updates modified zstd headers to yearless copyright
- Adds a new API in `include/linux/zstd.h` that is functionally
equivalent to the in-use subset of the current API. Functions are
renamed to avoid symbol collisions with zstd, to make it clear it is
not the upstream zstd API, and to follow the kernel style guide.
- Updates all callers to use the new API.
There are no functional changes in this patch. Since there are no
functional change, I felt it was okay to update all the callers in a
single patch. Once the API is approved, the callers are mechanically
changed.
This patch is preparing for the 3rd patch in this series, which updates
zstd to version 1.4.10. Since the upstream zstd API is no longer exposed
to callers, the update can happen transparently.
Signed-off-by: Nick Terrell <terrelln@fb.com>
Tested By: Paul Jones <paul@pauljones.id.au>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM/Clang v13.0.0 on x86-64
Tested-by: Jean-Denis Girard <jd.girard@sysnux.pf>
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This reverts commit bbaf9715f3f5b5ff0de71da91fcc34ee9c198ed8.
The kmaps in compression code are still needed and cause crashes on
32bit machines (ARM, x86). Reproducible eg. by running fstest btrfs/004
with enabled LZO or ZSTD compression.
Example stacktrace with ZSTD on a 32bit ARM machine:
Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = c4159ed3
[00000000] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 210 Comm: kworker/u2:3 Not tainted 5.14.0-rc79+ #12
Hardware name: Allwinner sun4i/sun5i Families
Workqueue: btrfs-delalloc btrfs_work_helper
PC is at mmiocpy+0x48/0x330
LR is at ZSTD_compressStream_generic+0x15c/0x28c
(mmiocpy) from [<c0629648>] (ZSTD_compressStream_generic+0x15c/0x28c)
(ZSTD_compressStream_generic) from [<c06297dc>] (ZSTD_compressStream+0x64/0xa0)
(ZSTD_compressStream) from [<c049444c>] (zstd_compress_pages+0x170/0x488)
(zstd_compress_pages) from [<c0496798>] (btrfs_compress_pages+0x124/0x12c)
(btrfs_compress_pages) from [<c043c068>] (compress_file_range+0x3c0/0x834)
(compress_file_range) from [<c043c4ec>] (async_cow_start+0x10/0x28)
(async_cow_start) from [<c0475c3c>] (btrfs_work_helper+0x100/0x230)
(btrfs_work_helper) from [<c014ef68>] (process_one_work+0x1b4/0x418)
(process_one_work) from [<c014f210>] (worker_thread+0x44/0x524)
(worker_thread) from [<c0156aa4>] (kthread+0x180/0x1b0)
(kthread) from [<c0100150>]
Link: https://lore.kernel.org/all/CAJCQCtT+OuemovPO7GZk8Y8=qtOObr0XTDp8jh4OHD6y84AFxw@mail.gmail.com/
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=214839
Signed-off-by: David Sterba <dsterba@suse.com>
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There are several bugs inside the function btrfs_decompress_buf2page()
- @start_byte doesn't take bvec.bv_offset into consideration
Thus it can't handle case where the target range is not page aligned.
- Too many helper variables
There are tons of helper variables, @buf_offset, @current_buf_start,
@start_byte, @prev_start_byte, @working_bytes, @bytes.
This hurts anyone who wants to read the function.
- No obvious main cursor for the iteartion
A new problem caused by previous problem.
- Comments for parameter list makes no sense
Like @buf_start is the offset to @buf, or offset inside the full
decompressed extent? (Spoiler alert, the later case)
And @total_out acts more like @buf_start + @size_of_buf.
The worst is @disk_start.
The real meaning of it is the file offset of the full decompressed
extent.
This patch will rework the whole function by:
- Add a proper comment with ASCII art to explain the parameter list
- Rework parameter list
The old @buf_start is renamed to @decompressed, to show how many bytes
are already decompressed inside the full decompressed extent.
The old @total_out is replaced by @buf_len, which is the decompressed
data size.
For old @disk_start and @bio, just pass @compressed_bio in.
- Use single main cursor
The main cursor will be @cur_file_offset, to show what's the current
file offset.
Other helper variables will be declared inside the main loop, and only
minimal amount of helper variables:
* offset_inside_decompressed_buf: The only real helper
* copy_start_file_offset: File offset we start memcpy
* bvec_file_offset: File offset of current bvec
Even with all these extensive comments, the final function is still
smaller than the original function, which is definitely a win.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
As we don't use highmem pages anymore, drop the kmap/kunmap. The kmap is
simply page_address and kunmap is a no-op.
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
The highmem flag is used for allocating pages for compression and for
raid56 pages. The high memory makes sense on 32bit systems but is not
without problems. On 64bit system's it's just another layer of wrappers.
The time the pages are allocated for compression or raid56 is relatively
short (about a transaction commit), so the pages are not blocked
indefinitely. As the number of pages depends on the amount of data being
written/read, there's a theoretical problem. A fast device on a 32bit
system could use most of the low memory pool, while with the highmem
allocation that would not happen. This was possibly the original idea
long time ago, but nowadays we optimize for 64bit systems.
This patch removes all usage of the __GFP_HIGHMEM flag for page
allocation, the kmap/kunmap are still in place and will be removed in
followup patches. Remaining is masking out the bit in
alloc_extent_state and __lookup_free_space_inode, that can safely stay.
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
There are many places where kmap/memset/kunmap patterns occur.
Use the newly lifted memzero_page() to eliminate direct uses of kmap and
leverage the new core functions use of kmap_local_page().
The development of this patch was aided by the following coccinelle
script:
// <smpl>
// SPDX-License-Identifier: GPL-2.0-only
// Find kmap/memset/kunmap pattern and replace with memset*page calls
//
// NOTE: Offsets and other expressions may be more complex than what the script
// will automatically generate. Therefore a catchall rule is provided to find
// the pattern which then must be evaluated by hand.
//
// Confidence: Low
// Copyright: (C) 2021 Intel Corporation
// URL: http://coccinelle.lip6.fr/
// Comments:
// Options:
//
// Then the memset pattern
//
@ memset_rule1 @
expression page, V, L, Off;
identifier ptr;
type VP;
@@
(
-VP ptr = kmap(page);
|
-ptr = kmap(page);
|
-VP ptr = kmap_atomic(page);
|
-ptr = kmap_atomic(page);
)
<+...
(
-memset(ptr, 0, L);
+memzero_page(page, 0, L);
|
-memset(ptr + Off, 0, L);
+memzero_page(page, Off, L);
|
-memset(ptr, V, L);
+memset_page(page, V, 0, L);
|
-memset(ptr + Off, V, L);
+memset_page(page, V, Off, L);
)
...+>
(
-kunmap(page);
|
-kunmap_atomic(ptr);
)
// Remove any pointers left unused
@
depends on memset_rule1
@
identifier memset_rule1.ptr;
type VP, VP1;
@@
-VP ptr;
... when != ptr;
? VP1 ptr;
//
// Catch all
//
@ memset_rule2 @
expression page;
identifier ptr;
expression GenTo, GenSize, GenValue;
type VP;
@@
(
-VP ptr = kmap(page);
|
-ptr = kmap(page);
|
-VP ptr = kmap_atomic(page);
|
-ptr = kmap_atomic(page);
)
<+...
(
//
// Some call sites have complex expressions within the memset/memcpy
// The follow are catch alls which need to be evaluated by hand.
//
-memset(GenTo, 0, GenSize);
+memzero_pageExtra(page, GenTo, GenSize);
|
-memset(GenTo, GenValue, GenSize);
+memset_pageExtra(page, GenValue, GenTo, GenSize);
)
...+>
(
-kunmap(page);
|
-kunmap_atomic(ptr);
)
// Remove any pointers left unused
@
depends on memset_rule2
@
identifier memset_rule2.ptr;
type VP, VP1;
@@
-VP ptr;
... when != ptr;
? VP1 ptr;
// </smpl>
Link: https://lkml.kernel.org/r/20210309212137.2610186-4-ira.weiny@intel.com
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
There are many places where the pattern kmap/memcpy/kunmap occurs.
This pattern was lifted to the core common functions
memcpy_[to|from]_page().
Use these new functions to reduce the code, eliminate direct uses of
kmap, and leverage the new core functions use of kmap_local_page().
Also, there is 1 place where a kmap/memcpy is followed by an
optional memset. Here we leave the kmap open coded to avoid remapping
the page but use kmap_local_page() directly.
Development of this patch was aided by the coccinelle script:
// <smpl>
// SPDX-License-Identifier: GPL-2.0-only
// Find kmap/memcpy/kunmap pattern and replace with memcpy*page calls
//
// NOTE: Offsets and other expressions may be more complex than what the script
// will automatically generate. Therefore a catchall rule is provided to find
// the pattern which then must be evaluated by hand.
//
// Confidence: Low
// Copyright: (C) 2021 Intel Corporation
// URL: http://coccinelle.lip6.fr/
// Comments:
// Options:
//
// simple memcpy version
//
@ memcpy_rule1 @
expression page, T, F, B, Off;
identifier ptr;
type VP;
@@
(
-VP ptr = kmap(page);
|
-ptr = kmap(page);
|
-VP ptr = kmap_atomic(page);
|
-ptr = kmap_atomic(page);
)
<+...
(
-memcpy(ptr + Off, F, B);
+memcpy_to_page(page, Off, F, B);
|
-memcpy(ptr, F, B);
+memcpy_to_page(page, 0, F, B);
|
-memcpy(T, ptr + Off, B);
+memcpy_from_page(T, page, Off, B);
|
-memcpy(T, ptr, B);
+memcpy_from_page(T, page, 0, B);
)
...+>
(
-kunmap(page);
|
-kunmap_atomic(ptr);
)
// Remove any pointers left unused
@
depends on memcpy_rule1
@
identifier memcpy_rule1.ptr;
type VP, VP1;
@@
-VP ptr;
... when != ptr;
? VP1 ptr;
//
// Some callers kmap without a temp pointer
//
@ memcpy_rule2 @
expression page, T, Off, F, B;
@@
<+...
(
-memcpy(kmap(page) + Off, F, B);
+memcpy_to_page(page, Off, F, B);
|
-memcpy(kmap(page), F, B);
+memcpy_to_page(page, 0, F, B);
|
-memcpy(T, kmap(page) + Off, B);
+memcpy_from_page(T, page, Off, B);
|
-memcpy(T, kmap(page), B);
+memcpy_from_page(T, page, 0, B);
)
...+>
-kunmap(page);
// No need for the ptr variable removal
//
// Catch all
//
@ memcpy_rule3 @
expression page;
expression GenTo, GenFrom, GenSize;
identifier ptr;
type VP;
@@
(
-VP ptr = kmap(page);
|
-ptr = kmap(page);
|
-VP ptr = kmap_atomic(page);
|
-ptr = kmap_atomic(page);
)
<+...
(
//
// Some call sites have complex expressions within the memcpy
// match a catch all to be evaluated by hand.
//
-memcpy(GenTo, GenFrom, GenSize);
+memcpy_to_pageExtra(page, GenTo, GenFrom, GenSize);
+memcpy_from_pageExtra(GenTo, page, GenFrom, GenSize);
)
...+>
(
-kunmap(page);
|
-kunmap_atomic(ptr);
)
// Remove any pointers left unused
@
depends on memcpy_rule3
@
identifier memcpy_rule3.ptr;
type VP, VP1;
@@
-VP ptr;
... when != ptr;
? VP1 ptr;
// <smpl>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Replace indirect calls to free_workspace by switch and calls to the
specific callbacks. This is mainly to get rid of the indirection due to
spectre vulnerability mitigations.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Replace indirect calls to alloc_workspace by switch and calls to the
specific callbacks. This is mainly to get rid of the indirection due to
spectre vulnerability mitigations.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Similar to get_workspace, majority of the callbacks is trivial, we don't
gain anything by the indirection, so replace them by a switch function.
Trivial callback implementations use the helper.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Majority of the callbacks is trivial, we don't gain anything by the
indirection, so replace them by a switch function.
ZLIB needs to adjust level in the callback and ZSTD workspace management
is complex, the rest is call to the helper.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
The indirect calls will be replaced by a switch in compression.c.
(Switch is faster than indirect calls with when Spectre mitigations are
enabled).
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Replace loop calling to all algos with a list of direct calls to the
cleanup manager callback. When that becomes trivial it is replaced by
direct call to the helper.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Replace loop calling to all algos with a list of direct calls to the
init manager callback. When that becomes trivial it is replaced by
direct call to the helper.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
There's a lot of indirection when the generic code calls into
algo-specific callbacks to reach the private workspace manager structure
and back to the generic code.
To simplify that, export the workspace manager for heuristic, LZO and
ZLIB, while ZSTD is going to use it's own manager.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
The indirect calls bring some overhead due to spectre vulnerability
mitigations. The number of cases is small and below the threshold
(10-20) where indirect call would be better.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Export compress_pages, decompress_bio and decompress callbacks for all
compression algos. The indirect calls will be replaced by a switch.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
The file ctree.h serves as a header for everything and has become quite
bloated. Split some helpers that are generic and create a new file that
should be the catch-all for code that's not btrfs-specific.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
The set_level callbacks do not do anything special and can be replaced
by a helper that uses the levels defined in the tables.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
The maximum and default levels do not change and can be defined
directly. The set_level callback was a temporary solution and will be
removed.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
The btrfs zstd workspace manager uses a background timer to reclaim not
recently used workspaces. I used spin_lock() from this context which
should have been caught with lockdep, but was not. This deadlock was
reported in bugzilla. The fix is to switch the zstd wsm lock to use
spin_lock_bh() from the softirq context.
This happened quite relibably on ppc64, unlike on other architectures.
[ 313.402874] ================================
[ 313.402875] WARNING: inconsistent lock state
[ 313.402879] 5.1.0-rc7 #1 Not tainted
[ 313.402880] --------------------------------
[ 313.402882] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
[ 313.402885] swapper/5/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
[ 313.402888] 0000000080d1120c (&(&wsm.lock)->rlock){+.?.}, at: .zstd_reclaim_timer_fn+0x40/0x230
[ 313.402895] {SOFTIRQ-ON-W} state was registered at:
[ 313.402899] .lock_acquire+0xd0/0x240
[ 313.402903] ._raw_spin_lock+0x34/0x60
[ 313.402906] .zstd_get_workspace+0xd0/0x360
[ 313.402908] .end_compressed_bio_read+0x3b8/0x540
[ 313.402911] .bio_endio+0x174/0x2c0
[ 313.402914] .end_workqueue_fn+0x4c/0x70
[ 313.402917] .normal_work_helper+0x138/0x7e0
[ 313.402920] .process_one_work+0x324/0x790
[ 313.402922] .worker_thread+0x68/0x570
[ 313.402925] .kthread+0x19c/0x1b0
[ 313.402928] .ret_from_kernel_thread+0x58/0x78
[ 313.402930] irq event stamp: 2629216
[ 313.402933] hardirqs last enabled at (2629216): [<c0000000009da738>] ._raw_spin_unlock_irq+0x38/0x60
[ 313.402936] hardirqs last disabled at (2629215): [<c0000000009da4c4>] ._raw_spin_lock_irq+0x24/0x70
[ 313.402939] softirqs last enabled at (2629212): [<c0000000000af9fc>] .irq_enter+0x8c/0xd0
[ 313.402942] softirqs last disabled at (2629213): [<c0000000000afb58>] .irq_exit+0x118/0x170
[ 313.402944]
other info that might help us debug this:
[ 313.402945] Possible unsafe locking scenario:
[ 313.402947] CPU0
[ 313.402948] ----
[ 313.402949] lock(&(&wsm.lock)->rlock);
[ 313.402951] <Interrupt>
[ 313.402952] lock(&(&wsm.lock)->rlock);
[ 313.402954]
*** DEADLOCK ***
[ 313.402957] 1 lock held by swapper/5/0:
[ 313.402958] #0: 000000004b612042 ((&wsm.timer)){+.-.}, at: .call_timer_fn+0x0/0x3c0
[ 313.402963]
stack backtrace:
[ 313.402967] CPU: 5 PID: 0 Comm: swapper/5 Not tainted 5.1.0-rc7 #1
[ 313.402968] Call Trace:
[ 313.402972] [c0000007fa262e70] [c0000000009b3294] .dump_stack+0xe0/0x15c (unreliable)
[ 313.402975] [c0000007fa262f10] [c000000000125548] .print_usage_bug+0x348/0x390
[ 313.402978] [c0000007fa262fd0] [c000000000125cb4] .mark_lock+0x724/0x930
[ 313.402981] [c0000007fa263080] [c000000000126c20] .__lock_acquire+0xc90/0x16a0
[ 313.402984] [c0000007fa2631b0] [c000000000128040] .lock_acquire+0xd0/0x240
[ 313.402987] [c0000007fa263280] [c0000000009da2b4] ._raw_spin_lock+0x34/0x60
[ 313.402990] [c0000007fa263300] [c00000000054b0b0] .zstd_reclaim_timer_fn+0x40/0x230
[ 313.402993] [c0000007fa2633d0] [c000000000158b38] .call_timer_fn+0xc8/0x3c0
[ 313.402996] [c0000007fa2634a0] [c000000000158f74] .expire_timers+0x144/0x260
[ 313.402999] [c0000007fa263550] [c000000000159178] .run_timer_softirq+0xe8/0x230
[ 313.403002] [c0000007fa263680] [c0000000009db288] .__do_softirq+0x188/0x5d4
[ 313.403004] [c0000007fa263790] [c0000000000afb58] .irq_exit+0x118/0x170
[ 313.403008] [c0000007fa263800] [c000000000028d88] .timer_interrupt+0x158/0x430
[ 313.403012] [c0000007fa2638b0] [c0000000000091d4] decrementer_common+0x134/0x140
[ 313.403017] --- interrupt: 901 at replay_interrupt_return+0x0/0x4
LR = .arch_local_irq_restore.part.0+0x68/0x80
[ 313.403020] [c0000007fa263bb0] [c00000000001a3ac] .arch_local_irq_restore.part.0+0x2c/0x80 (unreliable)
[ 313.403024] [c0000007fa263c30] [c0000000007bbbcc] .cpuidle_enter_state+0xec/0x670
[ 313.403027] [c0000007fa263d00] [c0000000000f5130] .call_cpuidle+0x40/0x90
[ 313.403031] [c0000007fa263d70] [c0000000000f554c] .do_idle+0x2dc/0x3a0
[ 313.403034] [c0000007fa263e30] [c0000000000f59ac] .cpu_startup_entry+0x2c/0x30
[ 313.403037] [c0000007fa263ea0] [c000000000045674] .start_secondary+0x644/0x650
[ 313.403041] [c0000007fa263f90] [c00000000000ad5c] start_secondary_prolog+0x10/0x14
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203517
Fixes: 3f93aef535c8 ("btrfs: add zstd compression level support")
CC: stable@vger.kernel.org # 5.1+
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
While calling functions inside zstd, we don't need to use the
indirection provided by the workspace_manager. Forward declarations are
added to maintain the function order of btrfs_compress_op.
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
The timer function, zstd_reclaim_timer_fn(), reschedules itself under
certain conditions. When cleaning up, take the lock and remove all
workspaces. This prevents the timer from rearming itself. Lastly, switch
to del_timer_sync() to ensure that the timer function can't trigger as
we're unloading.
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Zstd compression requires different amounts of memory for each level of
compression. The prior patches implemented indirection to allow for each
compression type to manage their workspaces independently. This patch
uses this indirection to implement compression level support for zstd.
To manage the additional memory require, each compression level has its
own queue of workspaces. A global LRU is used to help with reclaim.
Reclaim is done via a timer which provides a mechanism to decrease
memory utilization by keeping only workspaces around that are sized
appropriately. Forward progress is guaranteed by a preallocated max
workspace hidden from the LRU.
When getting a workspace, it uses a bitmap to identify the levels that
are populated and scans up. If it finds a workspace that is greater than
it, it uses it, but does not update the last_used time and the
corresponding place in the LRU. If we hit memory pressure, we sleep on
the max level workspace. We continue to rescan in case we can use a
smaller workspace, but eventually should be able to obtain the max level
workspace or allocate one again should memory pressure subside.
The memory requirement for decompression is the same as level 1, and
therefore can use any of available workspace.
The number of workspaces is bound by an upper limit of the workqueue's
limit which currently is 2 (percpu limit). The reclaim timer is used to
free inactive/improperly sized workspaces and is set to 307s to avoid
colliding with transaction commit (every 30s).
Repeating the experiment from v2 [1], the Silesia corpus was copied to a
btrfs filesystem 10 times and then read back after dropping the caches.
The btrfs filesystem was on an SSD.
Level Ratio Compression (MB/s) Decompression (MB/s) Memory (KB)
1 2.658 438.47 910.51 780
2 2.744 364.86 886.55 1004
3 2.801 336.33 828.41 1260
4 2.858 286.71 886.55 1260
5 2.916 212.77 556.84 1388
6 2.363 119.82 990.85 1516
7 3.000 154.06 849.30 1516
8 3.011 159.54 875.03 1772
9 3.025 100.51 940.15 1772
10 3.033 118.97 616.26 1772
11 3.036 94.19 802.11 1772
12 3.037 73.45 931.49 1772
13 3.041 55.17 835.26 2284
14 3.087 44.70 716.78 2547
15 3.126 37.30 878.84 2547
[1] https://lore.kernel.org/linux-btrfs/20181031181108.289340-1-terrelln@fb.com/
Cc: Nick Terrell <terrelln@fb.com>
Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
