This PR includes 5 commits that update the zstd library version:
1. Adds a new kernel-style wrapper around zstd. This wrapper API
is functionally equivalent to the subset of the current zstd API that is
currently used. The wrapper API changes to be kernel style so that the symbols
don't collide with zstd's symbols. The update to zstd-1.4.10 maintains the same
API and preserves the semantics, so that none of the callers need to be
updated. All callers are updated in the commit, because there are zero
functional changes.
2. Adds an indirection for `lib/decompress_unzstd.c` so it
doesn't depend on the layout of `lib/zstd/` to include every source file.
This allows the next patch to be automatically generated.
3. Imports the zstd-1.4.10 source code. This commit is automatically generated
from upstream zstd (https://github.com/facebook/zstd).
4. Adds me (terrelln@fb.com) as the maintainer of `lib/zstd`.
5. Fixes a newly added build warning for clang.
The discussion around this patchset has been pretty long, so I've included a
FAQ-style summary of the history of the patchset, and why we are taking this
approach.
Why do we need to update?
-------------------------
The zstd version in the kernel is based off of zstd-1.3.1, which is was released
August 20, 2017. Since then zstd has seen many bug fixes and performance
improvements. And, importantly, upstream zstd is continuously fuzzed by OSS-Fuzz,
and bug fixes aren't backported to older versions. So the only way to sanely get
these fixes is to keep up to date with upstream zstd. There are no known security
issues that affect the kernel, but we need to be able to update in case there
are. And while there are no known security issues, there are relevant bug fixes.
For example the problem with large kernel decompression has been fixed upstream
for over 2 years https://lkml.org/lkml/2020/9/29/27.
Additionally the performance improvements for kernel use cases are significant.
Measured for x86_64 on my Intel i9-9900k @ 3.6 GHz:
- BtrFS zstd compression at levels 1 and 3 is 5% faster
- BtrFS zstd decompression+read is 15% faster
- SquashFS zstd decompression+read is 15% faster
- F2FS zstd compression+write at level 3 is 8% faster
- F2FS zstd decompression+read is 20% faster
- ZRAM decompression+read is 30% faster
- Kernel zstd decompression is 35% faster
- Initramfs zstd decompression+build is 5% faster
On top of this, there are significant performance improvements coming down the
line in the next zstd release, and the new automated update patch generation
will allow us to pull them easily.
How is the update patch generated?
----------------------------------
The first two patches are preparation for updating the zstd version. Then the
3rd patch in the series imports upstream zstd into the kernel. This patch is
automatically generated from upstream. A script makes the necessary changes and
imports it into the kernel. The changes are:
- Replace all libc dependencies with kernel replacements and rewrite includes.
- Remove unncessary portability macros like: #if defined(_MSC_VER).
- Use the kernel xxhash instead of bundling it.
This automation gets tested every commit by upstream's continuous integration.
When we cut a new zstd release, we will submit a patch to the kernel to update
the zstd version in the kernel.
The automated process makes it easy to keep the kernel version of zstd up to
date. The current zstd in the kernel shares the guts of the code, but has a lot
of API and minor changes to work in the kernel. This is because at the time
upstream zstd was not ready to be used in the kernel envrionment as-is. But,
since then upstream zstd has evolved to support being used in the kernel as-is.
Why are we updating in one big patch?
-------------------------------------
The 3rd patch in the series is very large. This is because it is restructuring
the code, so it both deletes the existing zstd, and re-adds the new structure.
Future updates will be directly proportional to the changes in upstream zstd
since the last import. They will admittidly be large, as zstd is an actively
developed project, and has hundreds of commits between every release. However,
there is no other great alternative.
One option ruled out is to replay every upstream zstd commit. This is not feasible
for several reasons:
- There are over 3500 upstream commits since the zstd version in the kernel.
- The automation to automatically generate the kernel update was only added recently,
so older commits cannot easily be imported.
- Not every upstream zstd commit builds.
- Only zstd releases are "supported", and individual commits may have bugs that were
fixed before a release.
Another option to reduce the patch size would be to first reorganize to the new
file structure, and then apply the patch. However, the current kernel zstd is formatted
with clang-format to be more "kernel-like". But, the new method imports zstd as-is,
without additional formatting, to allow for closer correlation with upstream, and
easier debugging. So the patch wouldn't be any smaller.
It also doesn't make sense to import upstream zstd commit by commit going
forward. Upstream zstd doesn't support production use cases running of the
development branch. We have a lot of post-commit fuzzing that catches many bugs,
so indiviudal commits may be buggy, but fixed before a release. So going forward,
I intend to import every (important) zstd release into the Kernel.
So, while it isn't ideal, updating in one big patch is the only patch I see forward.
Who is responsible for this code?
---------------------------------
I am. This patchset adds me as the maintainer for zstd. Previously, there was no tree
for zstd patches. Because of that, there were several patches that either got ignored,
or took a long time to merge, since it wasn't clear which tree should pick them up.
I'm officially stepping up as maintainer, and setting up my tree as the path through
which zstd patches get merged. I'll make sure that patches to the kernel zstd get
ported upstream, so they aren't erased when the next version update happens.
How is this code tested?
------------------------
I tested every caller of zstd on x86_64 (BtrFS, ZRAM, SquashFS, F2FS, Kernel,
InitRAMFS). I also tested Kernel & InitRAMFS on i386 and aarch64. I checked both
performance and correctness.
Also, thanks to many people in the community who have tested these patches locally.
If you have tested the patches, please reply with a Tested-By so I can collect them
for the PR I will send to Linus.
Lastly, this code will bake in linux-next before being merged into v5.16.
Why update to zstd-1.4.10 when zstd-1.5.0 has been released?
------------------------------------------------------------
This patchset has been outstanding since 2020, and zstd-1.4.10 was the latest
release when it was created. Since the update patch is automatically generated
from upstream, I could generate it from zstd-1.5.0. However, there were some
large stack usage regressions in zstd-1.5.0, and are only fixed in the latest
development branch. And the latest development branch contains some new code that
needs to bake in the fuzzer before I would feel comfortable releasing to the
kernel.
Once this patchset has been merged, and we've released zstd-1.5.1, we can update
the kernel to zstd-1.5.1, and exercise the update process.
You may notice that zstd-1.4.10 doesn't exist upstream. This release is an
artifical release based off of zstd-1.4.9, with some fixes for the kernel
backported from the development branch. I will tag the zstd-1.4.10 release after
this patchset is merged, so the Linux Kernel is running a known version of zstd
that can be debugged upstream.
Why was a wrapper API added?
----------------------------
The first versions of this patchset migrated the kernel to the upstream zstd
API. It first added a shim API that supported the new upstream API with the old
code, then updated callers to use the new shim API, then transitioned to the
new code and deleted the shim API. However, Cristoph Hellwig suggested that we
transition to a kernel style API, and hide zstd's upstream API behind that.
This is because zstd's upstream API is supports many other use cases, and does
not follow the kernel style guide, while the kernel API is focused on the
kernel's use cases, and follows the kernel style guide.
Where is the previous discussion?
---------------------------------
Links for the discussions of the previous versions of the patch set.
The largest changes in the design of the patchset are driven by the discussions
in V11, V5, and V1. Sorry for the mix of links, I couldn't find most of the the
threads on lkml.org.
V12: https://www.spinics.net/lists/linux-crypto/msg58189.html
V11: https://lore.kernel.org/linux-btrfs/20210430013157.747152-1-nickrterrell@gmail.com/
V10: https://lore.kernel.org/lkml/20210426234621.870684-2-nickrterrell@gmail.com/
V9: https://lore.kernel.org/linux-btrfs/20210330225112.496213-1-nickrterrell@gmail.com/
V8: https://lore.kernel.org/linux-f2fs-devel/20210326191859.1542272-1-nickrterrell@gmail.com/
V7: https://lkml.org/lkml/2020/12/3/1195
V6: https://lkml.org/lkml/2020/12/2/1245
V5: https://lore.kernel.org/linux-btrfs/20200916034307.2092020-1-nickrterrell@gmail.com/
V4: https://www.spinics.net/lists/linux-btrfs/msg105783.html
V3: https://lkml.org/lkml/2020/9/23/1074
V2: https://www.spinics.net/lists/linux-btrfs/msg105505.html
V1: https://lore.kernel.org/linux-btrfs/20200916034307.2092020-1-nickrterrell@gmail.com/
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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Merge tag 'zstd-for-linus-v5.16' of git://github.com/terrelln/linux
Pull zstd update from Nick Terrell:
"Update to zstd-1.4.10.
Add myself as the maintainer of zstd and update the zstd version in
the kernel, which is now 4 years out of date, to a much more recent
zstd release. This includes bug fixes, much more extensive fuzzing,
and performance improvements. And generates the kernel zstd
automatically from upstream zstd, so it is easier to keep the zstd
verison up to date, and we don't fall so far out of date again.
This includes 5 commits that update the zstd library version:
- Adds a new kernel-style wrapper around zstd.
This wrapper API is functionally equivalent to the subset of the
current zstd API that is currently used. The wrapper API changes to
be kernel style so that the symbols don't collide with zstd's
symbols. The update to zstd-1.4.10 maintains the same API and
preserves the semantics, so that none of the callers need to be
updated. All callers are updated in the commit, because there are
zero functional changes.
- Adds an indirection for `lib/decompress_unzstd.c` so it doesn't
depend on the layout of `lib/zstd/` to include every source file.
This allows the next patch to be automatically generated.
- Imports the zstd-1.4.10 source code. This commit is automatically
generated from upstream zstd (https://github.com/facebook/zstd).
- Adds me (terrelln@fb.com) as the maintainer of `lib/zstd`.
- Fixes a newly added build warning for clang.
The discussion around this patchset has been pretty long, so I've
included a FAQ-style summary of the history of the patchset, and why
we are taking this approach.
Why do we need to update?
-------------------------
The zstd version in the kernel is based off of zstd-1.3.1, which is
was released August 20, 2017. Since then zstd has seen many bug fixes
and performance improvements. And, importantly, upstream zstd is
continuously fuzzed by OSS-Fuzz, and bug fixes aren't backported to
older versions. So the only way to sanely get these fixes is to keep
up to date with upstream zstd.
There are no known security issues that affect the kernel, but we need
to be able to update in case there are. And while there are no known
security issues, there are relevant bug fixes. For example the problem
with large kernel decompression has been fixed upstream for over 2
years [1]
Additionally the performance improvements for kernel use cases are
significant. Measured for x86_64 on my Intel i9-9900k @ 3.6 GHz:
- BtrFS zstd compression at levels 1 and 3 is 5% faster
- BtrFS zstd decompression+read is 15% faster
- SquashFS zstd decompression+read is 15% faster
- F2FS zstd compression+write at level 3 is 8% faster
- F2FS zstd decompression+read is 20% faster
- ZRAM decompression+read is 30% faster
- Kernel zstd decompression is 35% faster
- Initramfs zstd decompression+build is 5% faster
On top of this, there are significant performance improvements coming
down the line in the next zstd release, and the new automated update
patch generation will allow us to pull them easily.
How is the update patch generated?
----------------------------------
The first two patches are preparation for updating the zstd version.
Then the 3rd patch in the series imports upstream zstd into the
kernel. This patch is automatically generated from upstream. A script
makes the necessary changes and imports it into the kernel. The
changes are:
- Replace all libc dependencies with kernel replacements and rewrite
includes.
- Remove unncessary portability macros like: #if defined(_MSC_VER).
- Use the kernel xxhash instead of bundling it.
This automation gets tested every commit by upstream's continuous
integration. When we cut a new zstd release, we will submit a patch to
the kernel to update the zstd version in the kernel.
The automated process makes it easy to keep the kernel version of zstd
up to date. The current zstd in the kernel shares the guts of the
code, but has a lot of API and minor changes to work in the kernel.
This is because at the time upstream zstd was not ready to be used in
the kernel envrionment as-is. But, since then upstream zstd has
evolved to support being used in the kernel as-is.
Why are we updating in one big patch?
-------------------------------------
The 3rd patch in the series is very large. This is because it is
restructuring the code, so it both deletes the existing zstd, and
re-adds the new structure. Future updates will be directly
proportional to the changes in upstream zstd since the last import.
They will admittidly be large, as zstd is an actively developed
project, and has hundreds of commits between every release. However,
there is no other great alternative.
One option ruled out is to replay every upstream zstd commit. This is
not feasible for several reasons:
- There are over 3500 upstream commits since the zstd version in the
kernel.
- The automation to automatically generate the kernel update was only
added recently, so older commits cannot easily be imported.
- Not every upstream zstd commit builds.
- Only zstd releases are "supported", and individual commits may have
bugs that were fixed before a release.
Another option to reduce the patch size would be to first reorganize
to the new file structure, and then apply the patch. However, the
current kernel zstd is formatted with clang-format to be more
"kernel-like". But, the new method imports zstd as-is, without
additional formatting, to allow for closer correlation with upstream,
and easier debugging. So the patch wouldn't be any smaller.
It also doesn't make sense to import upstream zstd commit by commit
going forward. Upstream zstd doesn't support production use cases
running of the development branch. We have a lot of post-commit
fuzzing that catches many bugs, so indiviudal commits may be buggy,
but fixed before a release. So going forward, I intend to import every
(important) zstd release into the Kernel.
So, while it isn't ideal, updating in one big patch is the only patch
I see forward.
Who is responsible for this code?
---------------------------------
I am. This patchset adds me as the maintainer for zstd. Previously,
there was no tree for zstd patches. Because of that, there were
several patches that either got ignored, or took a long time to merge,
since it wasn't clear which tree should pick them up. I'm officially
stepping up as maintainer, and setting up my tree as the path through
which zstd patches get merged. I'll make sure that patches to the
kernel zstd get ported upstream, so they aren't erased when the next
version update happens.
How is this code tested?
------------------------
I tested every caller of zstd on x86_64 (BtrFS, ZRAM, SquashFS, F2FS,
Kernel, InitRAMFS). I also tested Kernel & InitRAMFS on i386 and
aarch64. I checked both performance and correctness.
Also, thanks to many people in the community who have tested these
patches locally.
Lastly, this code will bake in linux-next before being merged into
v5.16.
Why update to zstd-1.4.10 when zstd-1.5.0 has been released?
------------------------------------------------------------
This patchset has been outstanding since 2020, and zstd-1.4.10 was the
latest release when it was created. Since the update patch is
automatically generated from upstream, I could generate it from
zstd-1.5.0.
However, there were some large stack usage regressions in zstd-1.5.0,
and are only fixed in the latest development branch. And the latest
development branch contains some new code that needs to bake in the
fuzzer before I would feel comfortable releasing to the kernel.
Once this patchset has been merged, and we've released zstd-1.5.1, we
can update the kernel to zstd-1.5.1, and exercise the update process.
You may notice that zstd-1.4.10 doesn't exist upstream. This release
is an artifical release based off of zstd-1.4.9, with some fixes for
the kernel backported from the development branch. I will tag the
zstd-1.4.10 release after this patchset is merged, so the Linux Kernel
is running a known version of zstd that can be debugged upstream.
Why was a wrapper API added?
----------------------------
The first versions of this patchset migrated the kernel to the
upstream zstd API. It first added a shim API that supported the new
upstream API with the old code, then updated callers to use the new
shim API, then transitioned to the new code and deleted the shim API.
However, Cristoph Hellwig suggested that we transition to a kernel
style API, and hide zstd's upstream API behind that. This is because
zstd's upstream API is supports many other use cases, and does not
follow the kernel style guide, while the kernel API is focused on the
kernel's use cases, and follows the kernel style guide.
Where is the previous discussion?
---------------------------------
Links for the discussions of the previous versions of the patch set
below. The largest changes in the design of the patchset are driven by
the discussions in v11, v5, and v1. Sorry for the mix of links, I
couldn't find most of the the threads on lkml.org"
Link: https://lkml.org/lkml/2020/9/29/27 [1]
Link: https://www.spinics.net/lists/linux-crypto/msg58189.html [v12]
Link: https://lore.kernel.org/linux-btrfs/20210430013157.747152-1-nickrterrell@gmail.com/ [v11]
Link: https://lore.kernel.org/lkml/20210426234621.870684-2-nickrterrell@gmail.com/ [v10]
Link: https://lore.kernel.org/linux-btrfs/20210330225112.496213-1-nickrterrell@gmail.com/ [v9]
Link: https://lore.kernel.org/linux-f2fs-devel/20210326191859.1542272-1-nickrterrell@gmail.com/ [v8]
Link: https://lkml.org/lkml/2020/12/3/1195 [v7]
Link: https://lkml.org/lkml/2020/12/2/1245 [v6]
Link: https://lore.kernel.org/linux-btrfs/20200916034307.2092020-1-nickrterrell@gmail.com/ [v5]
Link: https://www.spinics.net/lists/linux-btrfs/msg105783.html [v4]
Link: https://lkml.org/lkml/2020/9/23/1074 [v3]
Link: https://www.spinics.net/lists/linux-btrfs/msg105505.html [v2]
Link: https://lore.kernel.org/linux-btrfs/20200916034307.2092020-1-nickrterrell@gmail.com/ [v1]
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>
* tag 'zstd-for-linus-v5.16' of git://github.com/terrelln/linux:
lib: zstd: Add cast to silence clang's -Wbitwise-instead-of-logical
MAINTAINERS: Add maintainer entry for zstd
lib: zstd: Upgrade to latest upstream zstd version 1.4.10
lib: zstd: Add decompress_sources.h for decompress_unzstd
lib: zstd: Add kernel-specific API
If we do a direct IO read or write when the buffer given by the user is
memory mapped to the file range we are going to do IO, we end up ending
in a deadlock. This is triggered by the new test case generic/647 from
fstests.
For a direct IO read we get a trace like this:
[967.872718] INFO: task mmap-rw-fault:12176 blocked for more than 120 seconds.
[967.874161] Not tainted 5.14.0-rc7-btrfs-next-95 #1
[967.874909] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[967.875983] task:mmap-rw-fault state:D stack: 0 pid:12176 ppid: 11884 flags:0x00000000
[967.875992] Call Trace:
[967.875999] __schedule+0x3ca/0xe10
[967.876015] schedule+0x43/0xe0
[967.876020] wait_extent_bit.constprop.0+0x1eb/0x260 [btrfs]
[967.876109] ? do_wait_intr_irq+0xb0/0xb0
[967.876118] lock_extent_bits+0x37/0x90 [btrfs]
[967.876150] btrfs_lock_and_flush_ordered_range+0xa9/0x120 [btrfs]
[967.876184] ? extent_readahead+0xa7/0x530 [btrfs]
[967.876214] extent_readahead+0x32d/0x530 [btrfs]
[967.876253] ? lru_cache_add+0x104/0x220
[967.876255] ? kvm_sched_clock_read+0x14/0x40
[967.876258] ? sched_clock_cpu+0xd/0x110
[967.876263] ? lock_release+0x155/0x4a0
[967.876271] read_pages+0x86/0x270
[967.876274] ? lru_cache_add+0x125/0x220
[967.876281] page_cache_ra_unbounded+0x1a3/0x220
[967.876291] filemap_fault+0x626/0xa20
[967.876303] __do_fault+0x36/0xf0
[967.876308] __handle_mm_fault+0x83f/0x15f0
[967.876322] handle_mm_fault+0x9e/0x260
[967.876327] __get_user_pages+0x204/0x620
[967.876332] ? get_user_pages_unlocked+0x69/0x340
[967.876340] get_user_pages_unlocked+0xd3/0x340
[967.876349] internal_get_user_pages_fast+0xbca/0xdc0
[967.876366] iov_iter_get_pages+0x8d/0x3a0
[967.876374] bio_iov_iter_get_pages+0x82/0x4a0
[967.876379] ? lock_release+0x155/0x4a0
[967.876387] iomap_dio_bio_actor+0x232/0x410
[967.876396] iomap_apply+0x12a/0x4a0
[967.876398] ? iomap_dio_rw+0x30/0x30
[967.876414] __iomap_dio_rw+0x29f/0x5e0
[967.876415] ? iomap_dio_rw+0x30/0x30
[967.876420] ? lock_acquired+0xf3/0x420
[967.876429] iomap_dio_rw+0xa/0x30
[967.876431] btrfs_file_read_iter+0x10b/0x140 [btrfs]
[967.876460] new_sync_read+0x118/0x1a0
[967.876472] vfs_read+0x128/0x1b0
[967.876477] __x64_sys_pread64+0x90/0xc0
[967.876483] do_syscall_64+0x3b/0xc0
[967.876487] entry_SYSCALL_64_after_hwframe+0x44/0xae
[967.876490] RIP: 0033:0x7fb6f2c038d6
[967.876493] RSP: 002b:00007fffddf586b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000011
[967.876496] RAX: ffffffffffffffda RBX: 0000000000001000 RCX: 00007fb6f2c038d6
[967.876498] RDX: 0000000000001000 RSI: 00007fb6f2c17000 RDI: 0000000000000003
[967.876499] RBP: 0000000000001000 R08: 0000000000000003 R09: 0000000000000000
[967.876501] R10: 0000000000001000 R11: 0000000000000246 R12: 0000000000000003
[967.876502] R13: 0000000000000000 R14: 00007fb6f2c17000 R15: 0000000000000000
This happens because at btrfs_dio_iomap_begin() we lock the extent range
and return with it locked - we only unlock in the endio callback, at
end_bio_extent_readpage() -> endio_readpage_release_extent(). Then after
iomap called the btrfs_dio_iomap_begin() callback, it triggers the page
faults that resulting in reading the pages, through the readahead callback
btrfs_readahead(), and through there we end to attempt to lock again the
same extent range (or a subrange of what we locked before), resulting in
the deadlock.
For a direct IO write, the scenario is a bit different, and it results in
trace like this:
[1132.442520] run fstests generic/647 at 2021-08-31 18:53:35
[1330.349355] INFO: task mmap-rw-fault:184017 blocked for more than 120 seconds.
[1330.350540] Not tainted 5.14.0-rc7-btrfs-next-95 #1
[1330.351158] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[1330.351900] task:mmap-rw-fault state:D stack: 0 pid:184017 ppid:183725 flags:0x00000000
[1330.351906] Call Trace:
[1330.351913] __schedule+0x3ca/0xe10
[1330.351930] schedule+0x43/0xe0
[1330.351935] btrfs_start_ordered_extent+0x108/0x1c0 [btrfs]
[1330.352020] ? do_wait_intr_irq+0xb0/0xb0
[1330.352028] btrfs_lock_and_flush_ordered_range+0x8c/0x120 [btrfs]
[1330.352064] ? extent_readahead+0xa7/0x530 [btrfs]
[1330.352094] extent_readahead+0x32d/0x530 [btrfs]
[1330.352133] ? lru_cache_add+0x104/0x220
[1330.352135] ? kvm_sched_clock_read+0x14/0x40
[1330.352138] ? sched_clock_cpu+0xd/0x110
[1330.352143] ? lock_release+0x155/0x4a0
[1330.352151] read_pages+0x86/0x270
[1330.352155] ? lru_cache_add+0x125/0x220
[1330.352162] page_cache_ra_unbounded+0x1a3/0x220
[1330.352172] filemap_fault+0x626/0xa20
[1330.352176] ? filemap_map_pages+0x18b/0x660
[1330.352184] __do_fault+0x36/0xf0
[1330.352189] __handle_mm_fault+0x1253/0x15f0
[1330.352203] handle_mm_fault+0x9e/0x260
[1330.352208] __get_user_pages+0x204/0x620
[1330.352212] ? get_user_pages_unlocked+0x69/0x340
[1330.352220] get_user_pages_unlocked+0xd3/0x340
[1330.352229] internal_get_user_pages_fast+0xbca/0xdc0
[1330.352246] iov_iter_get_pages+0x8d/0x3a0
[1330.352254] bio_iov_iter_get_pages+0x82/0x4a0
[1330.352259] ? lock_release+0x155/0x4a0
[1330.352266] iomap_dio_bio_actor+0x232/0x410
[1330.352275] iomap_apply+0x12a/0x4a0
[1330.352278] ? iomap_dio_rw+0x30/0x30
[1330.352292] __iomap_dio_rw+0x29f/0x5e0
[1330.352294] ? iomap_dio_rw+0x30/0x30
[1330.352306] btrfs_file_write_iter+0x238/0x480 [btrfs]
[1330.352339] new_sync_write+0x11f/0x1b0
[1330.352344] ? NF_HOOK_LIST.constprop.0.cold+0x31/0x3e
[1330.352354] vfs_write+0x292/0x3c0
[1330.352359] __x64_sys_pwrite64+0x90/0xc0
[1330.352365] do_syscall_64+0x3b/0xc0
[1330.352369] entry_SYSCALL_64_after_hwframe+0x44/0xae
[1330.352372] RIP: 0033:0x7f4b0a580986
[1330.352379] RSP: 002b:00007ffd34d75418 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
[1330.352382] RAX: ffffffffffffffda RBX: 0000000000001000 RCX: 00007f4b0a580986
[1330.352383] RDX: 0000000000001000 RSI: 00007f4b0a3a4000 RDI: 0000000000000003
[1330.352385] RBP: 00007f4b0a3a4000 R08: 0000000000000003 R09: 0000000000000000
[1330.352386] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
[1330.352387] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Unlike for reads, at btrfs_dio_iomap_begin() we return with the extent
range unlocked, but later when the page faults are triggered and we try
to read the extents, we end up btrfs_lock_and_flush_ordered_range() where
we find the ordered extent for our write, created by the iomap callback
btrfs_dio_iomap_begin(), and we wait for it to complete, which makes us
deadlock since we can't complete the ordered extent without reading the
pages (the iomap code only submits the bio after the pages are faulted
in).
Fix this by setting the nofault attribute of the given iov_iter and retry
the direct IO read/write if we get an -EFAULT error returned from iomap.
For reads, also disable page faults completely, this is because when we
read from a hole or a prealloc extent, we can still trigger page faults
due to the call to iov_iter_zero() done by iomap - at the moment, it is
oblivious to the value of the ->nofault attribute of an iov_iter.
We also need to keep track of the number of bytes written or read, and
pass it to iomap_dio_rw(), as well as use the new flag IOMAP_DIO_PARTIAL.
This depends on the iov_iter and iomap changes introduced in commit
c03098d4b9 ("Merge tag 'gfs2-v5.15-rc5-mmap-fault' of
git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2").
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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>
Functions gfs2_file_read_iter and gfs2_file_write_iter are both
accessing the user buffer to write to or read from while holding the
inode glock. In the most basic scenario, that buffer will not be
resident and it will be mapped to the same file. Accessing the buffer
will trigger a page fault, and gfs2 will deadlock trying to take the
same inode glock again while trying to handle that fault.
Fix that and similar, more complex scenarios by disabling page faults
while accessing user buffers. To make this work, introduce a small
amount of new infrastructure and fix some bugs that didn't trigger so
far, with page faults enabled.
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Merge tag 'gfs2-v5.15-rc5-mmap-fault' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
Pull gfs2 mmap + page fault deadlocks fixes from Andreas Gruenbacher:
"Functions gfs2_file_read_iter and gfs2_file_write_iter are both
accessing the user buffer to write to or read from while holding the
inode glock.
In the most basic deadlock scenario, that buffer will not be resident
and it will be mapped to the same file. Accessing the buffer will
trigger a page fault, and gfs2 will deadlock trying to take the same
inode glock again while trying to handle that fault.
Fix that and similar, more complex scenarios by disabling page faults
while accessing user buffers. To make this work, introduce a small
amount of new infrastructure and fix some bugs that didn't trigger so
far, with page faults enabled"
* tag 'gfs2-v5.15-rc5-mmap-fault' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
gfs2: Fix mmap + page fault deadlocks for direct I/O
iov_iter: Introduce nofault flag to disable page faults
gup: Introduce FOLL_NOFAULT flag to disable page faults
iomap: Add done_before argument to iomap_dio_rw
iomap: Support partial direct I/O on user copy failures
iomap: Fix iomap_dio_rw return value for user copies
gfs2: Fix mmap + page fault deadlocks for buffered I/O
gfs2: Eliminate ip->i_gh
gfs2: Move the inode glock locking to gfs2_file_buffered_write
gfs2: Introduce flag for glock holder auto-demotion
gfs2: Clean up function may_grant
gfs2: Add wrapper for iomap_file_buffered_write
iov_iter: Introduce fault_in_iov_iter_writeable
iov_iter: Turn iov_iter_fault_in_readable into fault_in_iov_iter_readable
gup: Turn fault_in_pages_{readable,writeable} into fault_in_{readable,writeable}
powerpc/kvm: Fix kvm_use_magic_page
iov_iter: Fix iov_iter_get_pages{,_alloc} page fault return value
The end goal of the current buffer overflow detection work[0] is to gain
full compile-time and run-time coverage of all detectable buffer overflows
seen via array indexing or memcpy(), memmove(), and memset(). The str*()
family of functions already have full coverage.
While much of the work for these changes have been on-going for many
releases (i.e. 0-element and 1-element array replacements, as well as
avoiding false positives and fixing discovered overflows[1]), this series
contains the foundational elements of several related buffer overflow
detection improvements by providing new common helpers and FORTIFY_SOURCE
changes needed to gain the introspection required for compiler visibility
into array sizes. Also included are a handful of already Acked instances
using the helpers (or related clean-ups), with many more waiting at the
ready to be taken via subsystem-specific trees[2]. The new helpers are:
- struct_group() for gaining struct member range introspection.
- memset_after() and memset_startat() for clearing to the end of structures.
- DECLARE_FLEX_ARRAY() for using flex arrays in unions or alone in structs.
Also included is the beginning of the refactoring of FORTIFY_SOURCE to
support memcpy() introspection, fix missing and regressed coverage under
GCC, and to prepare to fix the currently broken Clang support. Finishing
this work is part of the larger series[0], but depends on all the false
positives and buffer overflow bug fixes to have landed already and those
that depend on this series to land.
As part of the FORTIFY_SOURCE refactoring, a set of both a compile-time
and run-time tests are added for FORTIFY_SOURCE and the mem*()-family
functions respectively. The compile time tests have found a legitimate
(though corner-case) bug[6] already.
Please note that the appearance of "panic" and "BUG" in the
FORTIFY_SOURCE refactoring are the result of relocating existing code,
and no new use of those code-paths are expected nor desired.
Finally, there are two tree-wide conversions for 0-element arrays and
flexible array unions to gain sane compiler introspection coverage that
result in no known object code differences.
After this series (and the changes that have now landed via netdev
and usb), we are very close to finally being able to build with
-Warray-bounds and -Wzero-length-bounds. However, due corner cases in
GCC[3] and Clang[4], I have not included the last two patches that turn
on these options, as I don't want to introduce any known warnings to
the build. Hopefully these can be solved soon.
[0] https://lore.kernel.org/lkml/20210818060533.3569517-1-keescook@chromium.org/
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/?qt=grep&q=FORTIFY_SOURCE
[2] https://lore.kernel.org/lkml/202108220107.3E26FE6C9C@keescook/
[3] https://lore.kernel.org/lkml/3ab153ec-2798-da4c-f7b1-81b0ac8b0c5b@roeck-us.net/
[4] https://bugs.llvm.org/show_bug.cgi?id=51682
[5] https://lore.kernel.org/lkml/202109051257.29B29745C0@keescook/
[6] https://lore.kernel.org/lkml/20211020200039.170424-1-keescook@chromium.org/
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Merge tag 'overflow-v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull overflow updates from Kees Cook:
"The end goal of the current buffer overflow detection work[0] is to
gain full compile-time and run-time coverage of all detectable buffer
overflows seen via array indexing or memcpy(), memmove(), and
memset(). The str*() family of functions already have full coverage.
While much of the work for these changes have been on-going for many
releases (i.e. 0-element and 1-element array replacements, as well as
avoiding false positives and fixing discovered overflows[1]), this
series contains the foundational elements of several related buffer
overflow detection improvements by providing new common helpers and
FORTIFY_SOURCE changes needed to gain the introspection required for
compiler visibility into array sizes. Also included are a handful of
already Acked instances using the helpers (or related clean-ups), with
many more waiting at the ready to be taken via subsystem-specific
trees[2].
The new helpers are:
- struct_group() for gaining struct member range introspection
- memset_after() and memset_startat() for clearing to the end of
structures
- DECLARE_FLEX_ARRAY() for using flex arrays in unions or alone in
structs
Also included is the beginning of the refactoring of FORTIFY_SOURCE to
support memcpy() introspection, fix missing and regressed coverage
under GCC, and to prepare to fix the currently broken Clang support.
Finishing this work is part of the larger series[0], but depends on
all the false positives and buffer overflow bug fixes to have landed
already and those that depend on this series to land.
As part of the FORTIFY_SOURCE refactoring, a set of both a
compile-time and run-time tests are added for FORTIFY_SOURCE and the
mem*()-family functions respectively. The compile time tests have
found a legitimate (though corner-case) bug[6] already.
Please note that the appearance of "panic" and "BUG" in the
FORTIFY_SOURCE refactoring are the result of relocating existing code,
and no new use of those code-paths are expected nor desired.
Finally, there are two tree-wide conversions for 0-element arrays and
flexible array unions to gain sane compiler introspection coverage
that result in no known object code differences.
After this series (and the changes that have now landed via netdev and
usb), we are very close to finally being able to build with
-Warray-bounds and -Wzero-length-bounds.
However, due corner cases in GCC[3] and Clang[4], I have not included
the last two patches that turn on these options, as I don't want to
introduce any known warnings to the build. Hopefully these can be
solved soon"
Link: https://lore.kernel.org/lkml/20210818060533.3569517-1-keescook@chromium.org/ [0]
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/?qt=grep&q=FORTIFY_SOURCE [1]
Link: https://lore.kernel.org/lkml/202108220107.3E26FE6C9C@keescook/ [2]
Link: https://lore.kernel.org/lkml/3ab153ec-2798-da4c-f7b1-81b0ac8b0c5b@roeck-us.net/ [3]
Link: https://bugs.llvm.org/show_bug.cgi?id=51682 [4]
Link: https://lore.kernel.org/lkml/202109051257.29B29745C0@keescook/ [5]
Link: https://lore.kernel.org/lkml/20211020200039.170424-1-keescook@chromium.org/ [6]
* tag 'overflow-v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (30 commits)
fortify: strlen: Avoid shadowing previous locals
compiler-gcc.h: Define __SANITIZE_ADDRESS__ under hwaddress sanitizer
treewide: Replace 0-element memcpy() destinations with flexible arrays
treewide: Replace open-coded flex arrays in unions
stddef: Introduce DECLARE_FLEX_ARRAY() helper
btrfs: Use memset_startat() to clear end of struct
string.h: Introduce memset_startat() for wiping trailing members and padding
xfrm: Use memset_after() to clear padding
string.h: Introduce memset_after() for wiping trailing members/padding
lib: Introduce CONFIG_MEMCPY_KUNIT_TEST
fortify: Add compile-time FORTIFY_SOURCE tests
fortify: Allow strlen() and strnlen() to pass compile-time known lengths
fortify: Prepare to improve strnlen() and strlen() warnings
fortify: Fix dropped strcpy() compile-time write overflow check
fortify: Explicitly disable Clang support
fortify: Move remaining fortify helpers into fortify-string.h
lib/string: Move helper functions out of string.c
compiler_types.h: Remove __compiletime_object_size()
cm4000_cs: Use struct_group() to zero struct cm4000_dev region
can: flexcan: Use struct_group() to zero struct flexcan_regs regions
...
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Merge tag 'for-5.16-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
"The updates this time are more under the hood and enhancing existing
features (subpage with compression and zoned namespaces).
Performance related:
- misc small inode logging improvements (+3% throughput, -11% latency
on sample dbench workload)
- more efficient directory logging: bulk item insertion, less tree
searches and locking
- speed up bulk insertion of items into a b-tree, which is used when
logging directories, when running delayed items for directories
(fsync and transaction commits) and when running the slow path
(full sync) of an fsync (bulk creation run time -4%, deletion -12%)
Core:
- continued subpage support
- make defragmentation work
- make compression write work
- zoned mode
- support ZNS (zoned namespaces), zone capacity is number of
usable blocks in each zone
- add dedicated block group (zoned) for relocation, to prevent
out of order writes in some cases
- greedy block group reclaim, pick the ones with least usable
space first
- preparatory work for send protocol updates
- error handling improvements
- cleanups and refactoring
Fixes:
- lockdep warnings
- in show_devname callback, on seeding device
- device delete on loop device due to conversions to workqueues
- fix deadlock between chunk allocation and chunk btree modifications
- fix tracking of missing device count and status"
* tag 'for-5.16-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (140 commits)
btrfs: remove root argument from check_item_in_log()
btrfs: remove root argument from add_link()
btrfs: remove root argument from btrfs_unlink_inode()
btrfs: remove root argument from drop_one_dir_item()
btrfs: clear MISSING device status bit in btrfs_close_one_device
btrfs: call btrfs_check_rw_degradable only if there is a missing device
btrfs: send: prepare for v2 protocol
btrfs: fix comment about sector sizes supported in 64K systems
btrfs: update device path inode time instead of bd_inode
fs: export an inode_update_time helper
btrfs: fix deadlock when defragging transparent huge pages
btrfs: sysfs: convert scnprintf and snprintf to sysfs_emit
btrfs: make btrfs_super_block size match BTRFS_SUPER_INFO_SIZE
btrfs: update comments for chunk allocation -ENOSPC cases
btrfs: fix deadlock between chunk allocation and chunk btree modifications
btrfs: zoned: use greedy gc for auto reclaim
btrfs: check-integrity: stop storing the block device name in btrfsic_dev_state
btrfs: use btrfs_get_dev_args_from_path in dev removal ioctls
btrfs: add a btrfs_get_dev_args_from_path helper
btrfs: handle device lookup with btrfs_dev_lookup_args
...
Commit ccaa66c8dd reinstated the kmap/kunmap that had been dropped in
commit 8c945d32e6 ("btrfs: compression: drop kmap/kunmap from lzo").
However, it seems to have done so incorrectly due to the change not
reverting cleanly, and lzo_decompress_bio() ended up not having a
matching "kunmap()" to the "kmap()" that was put back.
Also, any assert that the page pointer is not NULL should be before the
kmap() of said pointer, since otherwise you'd just oops in the kmap()
before the assert would even trigger.
I noticed this when trying to verify my btrfs merge, and things not
adding up. I'm doing this fixup before re-doing my merge, because this
commit needs to also be backported to 5.15 (after verification from the
btrfs people).
Fixes: ccaa66c8dd ("Revert 'btrfs: compression: drop kmap/kunmap from lzo'")
Cc: David Sterba <dsterba@suse.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Merge tag 'for-5.16/bdev-size-2021-10-29' of git://git.kernel.dk/linux-block
Pull bdev size cleanups from Jens Axboe:
"Clean up the bdev size handling with new bdev_nr_bytes() helper"
* tag 'for-5.16/bdev-size-2021-10-29' of git://git.kernel.dk/linux-block: (34 commits)
partitions/ibm: use bdev_nr_sectors instead of open coding it
partitions/efi: use bdev_nr_bytes instead of open coding it
block/ioctl: use bdev_nr_sectors and bdev_nr_bytes
block: cache inode size in bdev
udf: use sb_bdev_nr_blocks
reiserfs: use sb_bdev_nr_blocks
ntfs: use sb_bdev_nr_blocks
jfs: use sb_bdev_nr_blocks
ext4: use sb_bdev_nr_blocks
block: add a sb_bdev_nr_blocks helper
block: use bdev_nr_bytes instead of open coding it in blkdev_fallocate
squashfs: use bdev_nr_bytes instead of open coding it
reiserfs: use bdev_nr_bytes instead of open coding it
pstore/blk: use bdev_nr_bytes instead of open coding it
ntfs3: use bdev_nr_bytes instead of open coding it
nilfs2: use bdev_nr_bytes instead of open coding it
nfs/blocklayout: use bdev_nr_bytes instead of open coding it
jfs: use bdev_nr_bytes instead of open coding it
hfsplus: use bdev_nr_sectors instead of open coding it
hfs: use bdev_nr_sectors instead of open coding it
...
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Merge tag 'for-5.16/block-2021-10-29' of git://git.kernel.dk/linux-block
Pull block updates from Jens Axboe:
- mq-deadline accounting improvements (Bart)
- blk-wbt timer fix (Andrea)
- Untangle the block layer includes (Christoph)
- Rework the poll support to be bio based, which will enable adding
support for polling for bio based drivers (Christoph)
- Block layer core support for multi-actuator drives (Damien)
- blk-crypto improvements (Eric)
- Batched tag allocation support (me)
- Request completion batching support (me)
- Plugging improvements (me)
- Shared tag set improvements (John)
- Concurrent queue quiesce support (Ming)
- Cache bdev in ->private_data for block devices (Pavel)
- bdev dio improvements (Pavel)
- Block device invalidation and block size improvements (Xie)
- Various cleanups, fixes, and improvements (Christoph, Jackie,
Masahira, Tejun, Yu, Pavel, Zheng, me)
* tag 'for-5.16/block-2021-10-29' of git://git.kernel.dk/linux-block: (174 commits)
blk-mq-debugfs: Show active requests per queue for shared tags
block: improve readability of blk_mq_end_request_batch()
virtio-blk: Use blk_validate_block_size() to validate block size
loop: Use blk_validate_block_size() to validate block size
nbd: Use blk_validate_block_size() to validate block size
block: Add a helper to validate the block size
block: re-flow blk_mq_rq_ctx_init()
block: prefetch request to be initialized
block: pass in blk_mq_tags to blk_mq_rq_ctx_init()
block: add rq_flags to struct blk_mq_alloc_data
block: add async version of bio_set_polled
block: kill DIO_MULTI_BIO
block: kill unused polling bits in __blkdev_direct_IO()
block: avoid extra iter advance with async iocb
block: Add independent access ranges support
blk-mq: don't issue request directly in case that current is to be blocked
sbitmap: silence data race warning
blk-cgroup: synchronize blkg creation against policy deactivation
block: refactor bio_iov_bvec_set()
block: add single bio async direct IO helper
...
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Merge tag 'for-5.15-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"Last minute fixes for crash on 32bit architectures when compression is
in use. It's a regression introduced in 5.15-rc and I'd really like
not let this into the final release, fixes via stable trees would add
unnecessary delay.
The problem is on 32bit architectures with highmem enabled, the pages
for compression may need to be kmapped, while the patches removed that
as we don't use GFP_HIGHMEM allocations anymore. The pages that don't
come from local allocation still may be from highmem. Despite being on
32bit there's enough such ARM machines in use so it's not a marginal
issue.
I did full reverts of the patches one by one instead of a huge one.
There's one exception for the "lzo" revert as there was an
intermediate patch touching the same code to make it compatible with
subpage. I can't revert that one too, so the revert in lzo.c is
manual. Qu Wenruo has worked on that with me and verified the changes"
* tag 'for-5.15-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
Revert "btrfs: compression: drop kmap/kunmap from lzo"
Revert "btrfs: compression: drop kmap/kunmap from zlib"
Revert "btrfs: compression: drop kmap/kunmap from zstd"
Revert "btrfs: compression: drop kmap/kunmap from generic helpers"
This reverts commit 8c945d32e6.
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.
The revert does not apply cleanly due to changes in a6e66e6f8c
("btrfs: rework lzo_decompress_bio() to make it subpage compatible")
that reworked the page iteration so the revert is done to be equivalent
to the original code.
Link: https://lore.kernel.org/all/CAJCQCtT+OuemovPO7GZk8Y8=qtOObr0XTDp8jh4OHD6y84AFxw@mail.gmail.com/
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=214839
Tested-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This reverts commit bbaf9715f3.
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>
The root argument passed to check_item_in_log() always matches the root
of the given directory, so it can be eliminated.
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 for tree-log.c:add_link() always matches the root of the
given directory and the given inode, so it can eliminated.
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_unlink_inode() and its callee,
__btrfs_unlink_inode(), always matches the root of the given directory and
the given inode. So remove the argument and make __btrfs_unlink_inode()
use the root of the directory.
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 for drop_one_dir_item() always matches the root of the
given directory inode, since each log tree is associated to one and only
one subvolume/root, so remove the argument.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Reported bug: https://github.com/kdave/btrfs-progs/issues/389
There's a problem with scrub reporting aborted status but returning
error code 0, on a filesystem with missing and readded device.
Roughly these steps:
- mkfs -d raid1 dev1 dev2
- fill with data
- unmount
- make dev1 disappear
- mount -o degraded
- copy more data
- make dev1 appear again
Running scrub afterwards reports that the command was aborted, but the
system log message says the exit code was 0.
It seems that the cause of the error is decrementing
fs_devices->missing_devices but not clearing device->dev_state. Every
time we umount filesystem, it would call close_ctree, And it would
eventually involve btrfs_close_one_device to close the device, but it
only decrements fs_devices->missing_devices but does not clear the
device BTRFS_DEV_STATE_MISSING bit. Worse, this bug will cause Integer
Overflow, because every time umount, fs_devices->missing_devices will
decrease. If fs_devices->missing_devices value hit 0, it would overflow.
With added debugging:
loop1: detected capacity change from 0 to 20971520
BTRFS: device fsid 56ad51f1-5523-463b-8547-c19486c51ebb devid 1 transid 21 /dev/loop1 scanned by systemd-udevd (2311)
loop2: detected capacity change from 0 to 20971520
BTRFS: device fsid 56ad51f1-5523-463b-8547-c19486c51ebb devid 2 transid 17 /dev/loop2 scanned by systemd-udevd (2313)
BTRFS info (device loop1): flagging fs with big metadata feature
BTRFS info (device loop1): allowing degraded mounts
BTRFS info (device loop1): using free space tree
BTRFS info (device loop1): has skinny extents
BTRFS info (device loop1): before clear_missing.00000000f706684d /dev/loop1 0
BTRFS warning (device loop1): devid 2 uuid 6635ac31-56dd-4852-873b-c60f5e2d53d2 is missing
BTRFS info (device loop1): before clear_missing.0000000000000000 /dev/loop2 1
BTRFS info (device loop1): flagging fs with big metadata feature
BTRFS info (device loop1): allowing degraded mounts
BTRFS info (device loop1): using free space tree
BTRFS info (device loop1): has skinny extents
BTRFS info (device loop1): before clear_missing.00000000f706684d /dev/loop1 0
BTRFS warning (device loop1): devid 2 uuid 6635ac31-56dd-4852-873b-c60f5e2d53d2 is missing
BTRFS info (device loop1): before clear_missing.0000000000000000 /dev/loop2 0
BTRFS info (device loop1): flagging fs with big metadata feature
BTRFS info (device loop1): allowing degraded mounts
BTRFS info (device loop1): using free space tree
BTRFS info (device loop1): has skinny extents
BTRFS info (device loop1): before clear_missing.00000000f706684d /dev/loop1 18446744073709551615
BTRFS warning (device loop1): devid 2 uuid 6635ac31-56dd-4852-873b-c60f5e2d53d2 is missing
BTRFS info (device loop1): before clear_missing.0000000000000000 /dev/loop2 18446744073709551615
If fs_devices->missing_devices is 0, next time it would be 18446744073709551615
After apply this patch, the fs_devices->missing_devices seems to be
right:
$ truncate -s 10g test1
$ truncate -s 10g test2
$ losetup /dev/loop1 test1
$ losetup /dev/loop2 test2
$ mkfs.btrfs -draid1 -mraid1 /dev/loop1 /dev/loop2 -f
$ losetup -d /dev/loop2
$ mount -o degraded /dev/loop1 /mnt/1
$ umount /mnt/1
$ mount -o degraded /dev/loop1 /mnt/1
$ umount /mnt/1
$ mount -o degraded /dev/loop1 /mnt/1
$ umount /mnt/1
$ dmesg
loop1: detected capacity change from 0 to 20971520
loop2: detected capacity change from 0 to 20971520
BTRFS: device fsid 15aa1203-98d3-4a66-bcae-ca82f629c2cd devid 1 transid 5 /dev/loop1 scanned by mkfs.btrfs (1863)
BTRFS: device fsid 15aa1203-98d3-4a66-bcae-ca82f629c2cd devid 2 transid 5 /dev/loop2 scanned by mkfs.btrfs (1863)
BTRFS info (device loop1): flagging fs with big metadata feature
BTRFS info (device loop1): allowing degraded mounts
BTRFS info (device loop1): disk space caching is enabled
BTRFS info (device loop1): has skinny extents
BTRFS info (device loop1): before clear_missing.00000000975bd577 /dev/loop1 0
BTRFS warning (device loop1): devid 2 uuid 8b333791-0b3f-4f57-b449-1c1ab6b51f38 is missing
BTRFS info (device loop1): before clear_missing.0000000000000000 /dev/loop2 1
BTRFS info (device loop1): checking UUID tree
BTRFS info (device loop1): flagging fs with big metadata feature
BTRFS info (device loop1): allowing degraded mounts
BTRFS info (device loop1): disk space caching is enabled
BTRFS info (device loop1): has skinny extents
BTRFS info (device loop1): before clear_missing.00000000975bd577 /dev/loop1 0
BTRFS warning (device loop1): devid 2 uuid 8b333791-0b3f-4f57-b449-1c1ab6b51f38 is missing
BTRFS info (device loop1): before clear_missing.0000000000000000 /dev/loop2 1
BTRFS info (device loop1): flagging fs with big metadata feature
BTRFS info (device loop1): allowing degraded mounts
BTRFS info (device loop1): disk space caching is enabled
BTRFS info (device loop1): has skinny extents
BTRFS info (device loop1): before clear_missing.00000000975bd577 /dev/loop1 0
BTRFS warning (device loop1): devid 2 uuid 8b333791-0b3f-4f57-b449-1c1ab6b51f38 is missing
BTRFS info (device loop1): before clear_missing.0000000000000000 /dev/loop2 1
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Li Zhang <zhanglikernel@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In open_ctree() in btrfs_check_rw_degradable() [1], we check each block
group individually if at least the minimum number of devices is available
for that profile. If all the devices are available, then we don't have to
check degradable.
[1]
open_ctree()
::
3559 if (!sb_rdonly(sb) && !btrfs_check_rw_degradable(fs_info, NULL)) {
Also before calling btrfs_check_rw_degradable() in open_ctee() at the
line number shown below [2] we call btrfs_read_chunk_tree() and down to
add_missing_dev() to record number of missing devices.
[2]
open_ctree()
::
3454 ret = btrfs_read_chunk_tree(fs_info);
btrfs_read_chunk_tree()
read_one_chunk() / read_one_dev()
add_missing_dev()
So, check if there is any missing device before btrfs_check_rw_degradable()
in open_ctree().
Also, with this the mount command could save ~16ms.[3] in the most
common case, that is no device is missing.
[3]
1) * 16934.96 us | btrfs_check_rw_degradable [btrfs]();
CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is preparatory work for send protocol update to version 2 and
higher.
We have many pending protocol update requests but still don't have the
basic protocol rev in place, the first thing that must happen is to do
the actual versioning support.
The protocol version is u32 and is a new member in the send ioctl
struct. Validity of the version field is backed by a new flag bit. Old
kernels would fail when a higher version is requested. Version protocol
0 will pick the highest supported version, BTRFS_SEND_STREAM_VERSION,
that's also exported in sysfs.
The version is still unchanged and will be increased once we have new
incompatible commands or stream updates.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Commit 95ea0486b2 ("btrfs: allow read-write for 4K sectorsize on 64K
page size systems") added write support for 4K sectorsize on a 64K
systems. Fix the now stale comments.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Christoph pointed out that I'm updating bdev->bd_inode for the device
time when we remove block devices from a btrfs file system, however this
isn't actually exposed to anything. The inode we want to update is the
one that's associated with the path to the device, usually on devtmpfs,
so that blkid notices the difference.
We still don't want to do the blkdev_open, so use kern_path() to get the
path to the given device and do the update time on that inode.
Fixes: 8f96a5bfa1 ("btrfs: update the bdev time directly when closing")
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Attempting to defragment a Btrfs file containing a transparent huge page
immediately deadlocks with the following stack trace:
#0 context_switch (kernel/sched/core.c:4940:2)
#1 __schedule (kernel/sched/core.c:6287:8)
#2 schedule (kernel/sched/core.c:6366:3)
#3 io_schedule (kernel/sched/core.c:8389:2)
#4 wait_on_page_bit_common (mm/filemap.c:1356:4)
#5 __lock_page (mm/filemap.c:1648:2)
#6 lock_page (./include/linux/pagemap.h:625:3)
#7 pagecache_get_page (mm/filemap.c:1910:4)
#8 find_or_create_page (./include/linux/pagemap.h:420:9)
#9 defrag_prepare_one_page (fs/btrfs/ioctl.c:1068:9)
#10 defrag_one_range (fs/btrfs/ioctl.c:1326:14)
#11 defrag_one_cluster (fs/btrfs/ioctl.c:1421:9)
#12 btrfs_defrag_file (fs/btrfs/ioctl.c:1523:9)
#13 btrfs_ioctl_defrag (fs/btrfs/ioctl.c:3117:9)
#14 btrfs_ioctl (fs/btrfs/ioctl.c:4872:10)
#15 vfs_ioctl (fs/ioctl.c:51:10)
#16 __do_sys_ioctl (fs/ioctl.c:874:11)
#17 __se_sys_ioctl (fs/ioctl.c:860:1)
#18 __x64_sys_ioctl (fs/ioctl.c:860:1)
#19 do_syscall_x64 (arch/x86/entry/common.c:50:14)
#20 do_syscall_64 (arch/x86/entry/common.c:80:7)
#21 entry_SYSCALL_64+0x7c/0x15b (arch/x86/entry/entry_64.S:113)
A huge page is represented by a compound page, which consists of a
struct page for each PAGE_SIZE page within the huge page. The first
struct page is the "head page", and the remaining are "tail pages".
Defragmentation attempts to lock each page in the range. However,
lock_page() on a tail page actually locks the corresponding head page.
So, if defragmentation tries to lock more than one struct page in a
compound page, it tries to lock the same head page twice and deadlocks
with itself.
Ideally, we should be able to defragment transparent huge pages.
However, THP for filesystems is currently read-only, so a lot of code is
not ready to use huge pages for I/O. For now, let's just return
ETXTBUSY.
This can be reproduced with the following on a kernel with
CONFIG_READ_ONLY_THP_FOR_FS=y:
$ cat create_thp_file.c
#include <fcntl.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/mman.h>
static const char zeroes[1024 * 1024];
static const size_t FILE_SIZE = 2 * 1024 * 1024;
int main(int argc, char **argv)
{
if (argc != 2) {
fprintf(stderr, "usage: %s PATH\n", argv[0]);
return EXIT_FAILURE;
}
int fd = creat(argv[1], 0777);
if (fd == -1) {
perror("creat");
return EXIT_FAILURE;
}
size_t written = 0;
while (written < FILE_SIZE) {
ssize_t ret = write(fd, zeroes,
sizeof(zeroes) < FILE_SIZE - written ?
sizeof(zeroes) : FILE_SIZE - written);
if (ret < 0) {
perror("write");
return EXIT_FAILURE;
}
written += ret;
}
close(fd);
fd = open(argv[1], O_RDONLY);
if (fd == -1) {
perror("open");
return EXIT_FAILURE;
}
/*
* Reserve some address space so that we can align the file mapping to
* the huge page size.
*/
void *placeholder_map = mmap(NULL, FILE_SIZE * 2, PROT_NONE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (placeholder_map == MAP_FAILED) {
perror("mmap (placeholder)");
return EXIT_FAILURE;
}
void *aligned_address =
(void *)(((uintptr_t)placeholder_map + FILE_SIZE - 1) & ~(FILE_SIZE - 1));
void *map = mmap(aligned_address, FILE_SIZE, PROT_READ | PROT_EXEC,
MAP_SHARED | MAP_FIXED, fd, 0);
if (map == MAP_FAILED) {
perror("mmap");
return EXIT_FAILURE;
}
if (madvise(map, FILE_SIZE, MADV_HUGEPAGE) < 0) {
perror("madvise");
return EXIT_FAILURE;
}
char *line = NULL;
size_t line_capacity = 0;
FILE *smaps_file = fopen("/proc/self/smaps", "r");
if (!smaps_file) {
perror("fopen");
return EXIT_FAILURE;
}
for (;;) {
for (size_t off = 0; off < FILE_SIZE; off += 4096)
((volatile char *)map)[off];
ssize_t ret;
bool this_mapping = false;
while ((ret = getline(&line, &line_capacity, smaps_file)) > 0) {
unsigned long start, end, huge;
if (sscanf(line, "%lx-%lx", &start, &end) == 2) {
this_mapping = (start <= (uintptr_t)map &&
(uintptr_t)map < end);
} else if (this_mapping &&
sscanf(line, "FilePmdMapped: %ld", &huge) == 1 &&
huge > 0) {
return EXIT_SUCCESS;
}
}
sleep(6);
rewind(smaps_file);
fflush(smaps_file);
}
}
$ ./create_thp_file huge
$ btrfs fi defrag -czstd ./huge
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Commit 2efc459d06 ("sysfs: Add sysfs_emit and sysfs_emit_at to format
sysfs out") merged in 5.10 introduced two new functions sysfs_emit() and
sysfs_emit_at() which are aware of the PAGE_SIZE limit of the output
buffer.
Use the above two new functions instead of scnprintf() and snprintf()
in various sysfs show().
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It's a common practice to avoid use sizeof(struct btrfs_super_block)
(3531), but to use BTRFS_SUPER_INFO_SIZE (4096).
The problem is that, sizeof(struct btrfs_super_block) doesn't match
BTRFS_SUPER_INFO_SIZE from the very beginning.
Furthermore, for all call sites except selftests, we always allocate
BTRFS_SUPER_INFO_SIZE space for super block, there isn't any real reason
to use the smaller value, and it doesn't really save any space.
So let's get rid of such confusing behavior, and unify those two values.
This modification also adds a new static_assert() to verify the size,
and moves the BTRFS_SUPER_INFO_* macros to the definition of
btrfs_super_block for the static_assert().
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Update the comments at btrfs_chunk_alloc() and do_chunk_alloc() that
describe which cases can lead to a failure to allocate metadata and system
space despite having previously reserved space. This adds one more reason
that I previously forgot to mention.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When a task is doing some modification to the chunk btree and it is not in
the context of a chunk allocation or a chunk removal, it can deadlock with
another task that is currently allocating a new data or metadata chunk.
These contexts are the following:
* When relocating a system chunk, when we need to COW the extent buffers
that belong to the chunk btree;
* When adding a new device (ioctl), where we need to add a new device item
to the chunk btree;
* When removing a device (ioctl), where we need to remove a device item
from the chunk btree;
* When resizing a device (ioctl), where we need to update a device item in
the chunk btree and may need to relocate a system chunk that lies beyond
the new device size when shrinking a device.
The problem happens due to a sequence of steps like the following:
1) Task A starts a data or metadata chunk allocation and it locks the
chunk mutex;
2) Task B is relocating a system chunk, and when it needs to COW an extent
buffer of the chunk btree, it has locked both that extent buffer as
well as its parent extent buffer;
3) Since there is not enough available system space, either because none
of the existing system block groups have enough free space or because
the only one with enough free space is in RO mode due to the relocation,
task B triggers a new system chunk allocation. It blocks when trying to
acquire the chunk mutex, currently held by task A;
4) Task A enters btrfs_chunk_alloc_add_chunk_item(), in order to insert
the new chunk item into the chunk btree and update the existing device
items there. But in order to do that, it has to lock the extent buffer
that task B locked at step 2, or its parent extent buffer, but task B
is waiting on the chunk mutex, which is currently locked by task A,
therefore resulting in a deadlock.
One example report when the deadlock happens with system chunk relocation:
INFO: task kworker/u9:5:546 blocked for more than 143 seconds.
Not tainted 5.15.0-rc3+ #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u9:5 state:D stack:25936 pid: 546 ppid: 2 flags:0x00004000
Workqueue: events_unbound btrfs_async_reclaim_metadata_space
Call Trace:
context_switch kernel/sched/core.c:4940 [inline]
__schedule+0xcd9/0x2530 kernel/sched/core.c:6287
schedule+0xd3/0x270 kernel/sched/core.c:6366
rwsem_down_read_slowpath+0x4ee/0x9d0 kernel/locking/rwsem.c:993
__down_read_common kernel/locking/rwsem.c:1214 [inline]
__down_read kernel/locking/rwsem.c:1223 [inline]
down_read_nested+0xe6/0x440 kernel/locking/rwsem.c:1590
__btrfs_tree_read_lock+0x31/0x350 fs/btrfs/locking.c:47
btrfs_tree_read_lock fs/btrfs/locking.c:54 [inline]
btrfs_read_lock_root_node+0x8a/0x320 fs/btrfs/locking.c:191
btrfs_search_slot_get_root fs/btrfs/ctree.c:1623 [inline]
btrfs_search_slot+0x13b4/0x2140 fs/btrfs/ctree.c:1728
btrfs_update_device+0x11f/0x500 fs/btrfs/volumes.c:2794
btrfs_chunk_alloc_add_chunk_item+0x34d/0xea0 fs/btrfs/volumes.c:5504
do_chunk_alloc fs/btrfs/block-group.c:3408 [inline]
btrfs_chunk_alloc+0x84d/0xf50 fs/btrfs/block-group.c:3653
flush_space+0x54e/0xd80 fs/btrfs/space-info.c:670
btrfs_async_reclaim_metadata_space+0x396/0xa90 fs/btrfs/space-info.c:953
process_one_work+0x9df/0x16d0 kernel/workqueue.c:2297
worker_thread+0x90/0xed0 kernel/workqueue.c:2444
kthread+0x3e5/0x4d0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
INFO: task syz-executor:9107 blocked for more than 143 seconds.
Not tainted 5.15.0-rc3+ #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:23200 pid: 9107 ppid: 7792 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:4940 [inline]
__schedule+0xcd9/0x2530 kernel/sched/core.c:6287
schedule+0xd3/0x270 kernel/sched/core.c:6366
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425
__mutex_lock_common kernel/locking/mutex.c:669 [inline]
__mutex_lock+0xc96/0x1680 kernel/locking/mutex.c:729
btrfs_chunk_alloc+0x31a/0xf50 fs/btrfs/block-group.c:3631
find_free_extent_update_loop fs/btrfs/extent-tree.c:3986 [inline]
find_free_extent+0x25cb/0x3a30 fs/btrfs/extent-tree.c:4335
btrfs_reserve_extent+0x1f1/0x500 fs/btrfs/extent-tree.c:4415
btrfs_alloc_tree_block+0x203/0x1120 fs/btrfs/extent-tree.c:4813
__btrfs_cow_block+0x412/0x1620 fs/btrfs/ctree.c:415
btrfs_cow_block+0x2f6/0x8c0 fs/btrfs/ctree.c:570
btrfs_search_slot+0x1094/0x2140 fs/btrfs/ctree.c:1768
relocate_tree_block fs/btrfs/relocation.c:2694 [inline]
relocate_tree_blocks+0xf73/0x1770 fs/btrfs/relocation.c:2757
relocate_block_group+0x47e/0xc70 fs/btrfs/relocation.c:3673
btrfs_relocate_block_group+0x48a/0xc60 fs/btrfs/relocation.c:4070
btrfs_relocate_chunk+0x96/0x280 fs/btrfs/volumes.c:3181
__btrfs_balance fs/btrfs/volumes.c:3911 [inline]
btrfs_balance+0x1f03/0x3cd0 fs/btrfs/volumes.c:4301
btrfs_ioctl_balance+0x61e/0x800 fs/btrfs/ioctl.c:4137
btrfs_ioctl+0x39ea/0x7b70 fs/btrfs/ioctl.c:4949
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
So fix this by making sure that whenever we try to modify the chunk btree
and we are neither in a chunk allocation context nor in a chunk remove
context, we reserve system space before modifying the chunk btree.
Reported-by: Hao Sun <sunhao.th@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/CACkBjsax51i4mu6C0C3vJqQN3NR_iVuucoeG3U1HXjrgzn5FFQ@mail.gmail.com/
Fixes: 79bd37120b ("btrfs: rework chunk allocation to avoid exhaustion of the system chunk array")
CC: stable@vger.kernel.org # 5.14+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently auto reclaim of unusable zones reclaims the block-groups in
the order they have been added to the reclaim list.
Change this to a greedy algorithm by sorting the list so we have the
block-groups with the least amount of valid bytes reclaimed first.
Note: we can't splice the block groups from reclaim_bgs to let the sort
happen outside of the lock. The block groups can be still in use by
other parts eg. via bg_list and we must hold unused_bgs_lock while
processing them.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ write note and comment why we can't splice the list ]
Signed-off-by: David Sterba <dsterba@suse.com>
Just use the %pg format specifier in all the debug printks previously
using it. Note that both bdevname and the %pg specifier never print
a pathname, so the kbasename call wasn't needed to start with.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
[ adjust messages and indentation ]
Signed-off-by: David Sterba <dsterba@suse.com>
For device removal and replace we call btrfs_find_device_by_devspec,
which if we give it a device path and nothing else will call
btrfs_get_dev_args_from_path, which opens the block device and reads the
super block and then looks up our device based on that.
However at this point we're holding the sb write "lock", so reading the
block device pulls in the dependency of ->open_mutex, which produces the
following lockdep splat
======================================================
WARNING: possible circular locking dependency detected
5.14.0-rc2+ #405 Not tainted
------------------------------------------------------
losetup/11576 is trying to acquire lock:
ffff9bbe8cded938 ((wq_completion)loop0){+.+.}-{0:0}, at: flush_workqueue+0x67/0x5e0
but task is already holding lock:
ffff9bbe88e4fc68 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x660 [loop]
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (&lo->lo_mutex){+.+.}-{3:3}:
__mutex_lock+0x7d/0x750
lo_open+0x28/0x60 [loop]
blkdev_get_whole+0x25/0xf0
blkdev_get_by_dev.part.0+0x168/0x3c0
blkdev_open+0xd2/0xe0
do_dentry_open+0x161/0x390
path_openat+0x3cc/0xa20
do_filp_open+0x96/0x120
do_sys_openat2+0x7b/0x130
__x64_sys_openat+0x46/0x70
do_syscall_64+0x38/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
-> #3 (&disk->open_mutex){+.+.}-{3:3}:
__mutex_lock+0x7d/0x750
blkdev_get_by_dev.part.0+0x56/0x3c0
blkdev_get_by_path+0x98/0xa0
btrfs_get_bdev_and_sb+0x1b/0xb0
btrfs_find_device_by_devspec+0x12b/0x1c0
btrfs_rm_device+0x127/0x610
btrfs_ioctl+0x2a31/0x2e70
__x64_sys_ioctl+0x80/0xb0
do_syscall_64+0x38/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
-> #2 (sb_writers#12){.+.+}-{0:0}:
lo_write_bvec+0xc2/0x240 [loop]
loop_process_work+0x238/0xd00 [loop]
process_one_work+0x26b/0x560
worker_thread+0x55/0x3c0
kthread+0x140/0x160
ret_from_fork+0x1f/0x30
-> #1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}:
process_one_work+0x245/0x560
worker_thread+0x55/0x3c0
kthread+0x140/0x160
ret_from_fork+0x1f/0x30
-> #0 ((wq_completion)loop0){+.+.}-{0:0}:
__lock_acquire+0x10ea/0x1d90
lock_acquire+0xb5/0x2b0
flush_workqueue+0x91/0x5e0
drain_workqueue+0xa0/0x110
destroy_workqueue+0x36/0x250
__loop_clr_fd+0x9a/0x660 [loop]
block_ioctl+0x3f/0x50
__x64_sys_ioctl+0x80/0xb0
do_syscall_64+0x38/0x90
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/11576:
#0: ffff9bbe88e4fc68 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x660 [loop]
stack backtrace:
CPU: 0 PID: 11576 Comm: losetup Not tainted 5.14.0-rc2+ #405
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
Call Trace:
dump_stack_lvl+0x57/0x72
check_noncircular+0xcf/0xf0
? stack_trace_save+0x3b/0x50
__lock_acquire+0x10ea/0x1d90
lock_acquire+0xb5/0x2b0
? flush_workqueue+0x67/0x5e0
? lockdep_init_map_type+0x47/0x220
flush_workqueue+0x91/0x5e0
? flush_workqueue+0x67/0x5e0
? verify_cpu+0xf0/0x100
drain_workqueue+0xa0/0x110
destroy_workqueue+0x36/0x250
__loop_clr_fd+0x9a/0x660 [loop]
? blkdev_ioctl+0x8d/0x2a0
block_ioctl+0x3f/0x50
__x64_sys_ioctl+0x80/0xb0
do_syscall_64+0x38/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f31b02404cb
Instead what we want to do is populate our device lookup args before we
grab any locks, and then pass these args into btrfs_rm_device(). From
there we can find the device and do the appropriate removal.
Suggested-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We are going to want to populate our device lookup args outside of any
locks and then do the actual device lookup later, so add a helper to do
this work and make btrfs_find_device_by_devspec() use this helper for
now.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have a lot of device lookup functions that all do something slightly
different. Clean this up by adding a struct to hold the different
lookup criteria, and then pass this around to btrfs_find_device() so it
can do the proper matching based on the lookup criteria.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There's a subtle case where if we're removing the seed device from a
file system we need to free its private copy of the fs_devices. However
we do not need to call close_fs_devices(), because at this point there
are no devices left to close as we've closed the last one. The only
thing that close_fs_devices() does is decrement ->opened, which should
be 1. We want to avoid calling close_fs_devices() here because it has a
lockdep_assert_held(&uuid_mutex), and we are going to stop holding the
uuid_mutex in this path.
So simply decrement the ->opened counter like we should, and then clean
up like normal. Also add a comment explaining what we're doing here as
I initially removed this code erroneously.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A bug was was checking a wrong device count before we delete the struct
btrfs_fs_devices in btrfs_rm_device(). To avoid future confusion and
easy reference add a comment about the various device counts that we have
in the struct btrfs_fs_devices.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For both sprout and seed fsids,
btrfs_fs_devices::num_devices provides device count including missing
btrfs_fs_devices::open_devices provides device count excluding missing
We create a dummy struct btrfs_device for the missing device, so
num_devices != open_devices when there is a missing device.
In btrfs_rm_devices() we wrongly check for %cur_devices->open_devices
before freeing the seed fs_devices. Instead we should check for
%cur_devices->num_devices.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
At replay_dir_deletes(), if find_dir_range() returns an error we break out
of the main while loop and then assign a value of 0 (success) to the 'ret'
variable, resulting in completely ignoring that an error happened. Fix
that by jumping to the 'out' label when find_dir_range() returns an error
(negative value).
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The member btrfs_bio::logical is only initialized by two call sites:
- btrfs_repair_one_sector()
No corresponding site to utilize it.
- btrfs_submit_direct()
The corresponding site to utilize it is btrfs_check_read_dio_bio().
However for btrfs_check_read_dio_bio(), we can grab the file_offset from
btrfs_dio_private::file_offset directly.
Thus it turns out we don't really need that btrfs_bio::logical member at
all.
For btrfs_bio, the logical bytenr can be fetched from its
bio->bi_iter.bi_sector directly.
So let's just remove the member to save 8 bytes for structure btrfs_bio.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The naming of "logical_offset" can be confused with logical bytenr of
the dio range.
In fact it's file offset, and the naming "file_offset" is already widely
used in all other sites.
Just do the rename to avoid confusion.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Using local kmaps slightly reduces the chances to stray writes, and
the bvec interface cleans up the code a little bit.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_update_block_group() accounts for the number of bytes allocated or
freed. Argument @alloc specifies whether the call is for alloc or free.
Convert the argument @alloc type from int to bool.
Reviewed-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>
Now that real_root is only used in ref-verify core gate it behind
CONFIG_BTRFS_FS_REF_VERIFY ifdef. This shrinks the size of pending
delayed refs by 8 bytes per ref, of which we can have many at any one
time depending on intensity of the workload. Also change the comment
about the member as it no longer deals with qgroups.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Instead of checking whether qgroup processing for a dealyed ref has to
happen in the core of delayed ref, simply pull the check at init time of
respective delayed ref structures. This eliminates the final use of
real_root in delayed-ref core paving the way to making this member
optional.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In order to make 'real_root' used only in ref-verify it's required to
have the necessary context to perform the same checks that this member
is used for. So add 'mod_root' which will contain the root on behalf of
which a delayed ref was created and a 'skip_group' parameter which
will contain callsite-specific override of skip_qgroup.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The real_root field is going to be used only by ref-verify tool so limit
its use outside of it. Blocks belonging to the chunk root will always
have it as an owner so the check is equivalent.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Both data and metadata delayed ref structures have fields named
root/ref_root respectively. Those are somewhat cryptic and don't really
convey the real meaning. In fact those roots are really the original
owners of the respective block (i.e in case of a snapshot a data delayed
ref will contain the original root that owns the given block). Rename
those fields accordingly and adjust comments.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Error injection stressing uncovered a busy loop in our data reclaim
loop. There are two cases here, one where we loop creating block groups
until space_info->full is set, or in the main loop we will skip erroring
out any tickets if space_info->full == 0. Unfortunately if we aborted
the transaction then we will never allocate chunks or reclaim any space
and thus never get ->full, and you'll see stack traces like this:
watchdog: BUG: soft lockup - CPU#0 stuck for 26s! [kworker/u4:4:139]
CPU: 0 PID: 139 Comm: kworker/u4:4 Tainted: G W 5.13.0-rc1+ #328
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
Workqueue: events_unbound btrfs_async_reclaim_data_space
RIP: 0010:btrfs_join_transaction+0x12/0x20
RSP: 0018:ffffb2b780b77de0 EFLAGS: 00000246
RAX: ffffb2b781863d58 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000801 RSI: ffff987952b57400 RDI: ffff987940aa3000
RBP: ffff987954d55000 R08: 0000000000000001 R09: ffff98795539e8f0
R10: 000000000000000f R11: 000000000000000f R12: ffffffffffffffff
R13: ffff987952b574c8 R14: ffff987952b57400 R15: 0000000000000008
FS: 0000000000000000(0000) GS:ffff9879bbc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0703da4000 CR3: 0000000113398004 CR4: 0000000000370ef0
Call Trace:
flush_space+0x4a8/0x660
btrfs_async_reclaim_data_space+0x55/0x130
process_one_work+0x1e9/0x380
worker_thread+0x53/0x3e0
? process_one_work+0x380/0x380
kthread+0x118/0x140
? __kthread_bind_mask+0x60/0x60
ret_from_fork+0x1f/0x30
Fix this by checking to see if we have a btrfs fs error in either of the
reclaim loops, and if so fail the tickets and bail. In addition to
this, fix maybe_fail_all_tickets() to not try to grant tickets if we've
aborted, simply fail everything.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have a few flags that are inconsistently used to describe the fs in
different states of failure. As of 5963ffcaf3 ("btrfs: always abort
the transaction if we abort a trans handle") we will always set
BTRFS_FS_STATE_ERROR if we abort, so we don't have to check both ABORTED
and ERROR to see if things have gone wrong. Add a helper to check
BTRFS_FS_STATE_ERROR and then convert all checkers of FS_STATE_ERROR to
use the helper.
The TRANS_ABORTED bit check was added in af72273381 ("Btrfs: clean up
resources during umount after trans is aborted") but is not actually
specific.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently we will abort the transaction if we get a random error (like
-EIO) while trying to remove the directory entries from the root log
during rename.
However since these are simply log tree related errors, we can mark the
trans as needing a full commit. Then if the error was truly
catastrophic we'll hit it during the normal commit and abort as
appropriate.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Linus Torvalds