Merge tag 'for-6.9-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs updates from David Sterba:
"Mostly stabilization, refactoring and cleanup changes. There rest are
m

Merge tag 'for-6.9-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs updates from David Sterba:
"Mostly stabilization, refactoring and cleanup changes. There rest are
minor performance optimizations due to caching or lock contention
reduction and a few notable fixes.

Performance improvements:

- minor speedup in logging when repeatedly allocated structure is
preallocated only once, improves latency and decreases lock
contention

- minor throughput increase (+6%), reduced lock contention after
clearing delayed allocation bits, applies to several common
workload types

- skip full quota rescan if a new relation is added in the same
transaction

Fixes:

- zstd fix for inline compressed file in subpage mode, updated
version from the 6.8 time

- proper qgroup inheritance ioctl parameter validation

- more fiemap followup fixes after reduced locking done in 6.8:
- fix race when detecting delalloc ranges

Core changes:

- more debugging code:
- added assertions for a very rare crash in raid56 calculation
- tree-checker dumps page state to give more insights into
possible reference counting issues

- add checksum calculation offloading sysfs knob, for now enabled
under DEBUG only to determine a good heuristic for deciding the
offload or synchronous, depends on various factors (block group
profile, device speed) and is not as clear as initially thought
(checksum type)

- error handling improvements, added assertions

- more page to folio conversion (defrag, truncate), cached size and
shift

- preparation for more fine grained locking of sectors in subpage
mode

- cleanups and refactoring:
- include cleanups, forward declarations
- pointer-to-structure helpers
- redundant argument removals
- removed unused code
- slab cache updates, last use of SLAB_MEM_SPREAD removed"

* tag 'for-6.9-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (114 commits)
btrfs: reuse cloned extent buffer during fiemap to avoid re-allocations
btrfs: fix race when detecting delalloc ranges during fiemap
btrfs: fix off-by-one chunk length calculation at contains_pending_extent()
btrfs: qgroup: allow quick inherit if snapshot is created and added to the same parent
btrfs: qgroup: validate btrfs_qgroup_inherit parameter
btrfs: include device major and minor numbers in the device scan notice
btrfs: mark btrfs_put_caching_control() static
btrfs: remove SLAB_MEM_SPREAD flag use
btrfs: qgroup: always free reserved space for extent records
btrfs: tree-checker: dump the page status if hit something wrong
btrfs: compression: remove dead comments in btrfs_compress_heuristic()
btrfs: subpage: make writer lock utilize bitmap
btrfs: subpage: make reader lock utilize bitmap
btrfs: unexport btrfs_subpage_start_writer() and btrfs_subpage_end_and_test_writer()
btrfs: pass a valid extent map cache pointer to __get_extent_map()
btrfs: merge btrfs_del_delalloc_inode() helpers
btrfs: pass btrfs_device to btrfs_scratch_superblocks()
btrfs: handle transaction commit errors in flush_reservations()
btrfs: use KMEM_CACHE() to create btrfs_free_space cache
btrfs: use KMEM_CACHE() to create delayed ref caches
...

show more ...

btrfs: compression: remove dead comments in btrfs_compress_heuristic()

Since commit a440d48c7f93 ("Btrfs: heuristic: implement sampling
logic"), btrfs_compress_heuristic() is no longer a simple "ret

btrfs: compression: remove dead comments in btrfs_compress_heuristic()

Since commit a440d48c7f93 ("Btrfs: heuristic: implement sampling
logic"), btrfs_compress_heuristic() is no longer a simple "return true",
but more complex to determine if we should compress.

Thus the comment is dead and can be confusing, just remove it.

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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btrfs: add helper to get fs_info from struct inode pointer

Add a convenience helper to get a fs_info from a VFS inode pointer
instead of open coding the chain or using btrfs_sb() that in some cases

btrfs: add helper to get fs_info from struct inode pointer

Add a convenience helper to get a fs_info from a VFS inode pointer
instead of open coding the chain or using btrfs_sb() that in some cases
does one more pointer hop. This is implemented as a macro (still with
type checking) so we don't need full definitions of struct btrfs_inode,
btrfs_root or btrfs_fs_info.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: add helpers to get fs_info from page/folio pointers

Add convenience helpers to get a fs_info from a page or folio pointer
instead of open coding the chain or using btrfs_sb() that in some cas

btrfs: add helpers to get fs_info from page/folio pointers

Add convenience helpers to get a fs_info from a page or folio pointer
instead of open coding the chain or using btrfs_sb() that in some cases
does one more pointer hop. This is implemented as a macro (still with
type checking) so we don't need full definitions of struct page, folio,
btrfs_root and btrfs_fs_info. The latter can't be static inlines as this
would create loop between ctree.h <-> fs.h, or the headers would have to
be restructured.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: remove unused included headers

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 (w

btrfs: remove unused included headers

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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Merge tag 'v6.8-rc4' into x86/percpu, to resolve conflicts and refresh the branch

Conflicts:
arch/x86/include/asm/percpu.h
arch/x86/include/asm/text-patching.h

Signed-off-by: Ingo Molnar <mingo@k

Merge tag 'v6.8-rc4' into x86/percpu, to resolve conflicts and refresh the branch

Conflicts:
arch/x86/include/asm/percpu.h
arch/x86/include/asm/text-patching.h

Signed-off-by: Ingo Molnar <mingo@kernel.org>

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Merge branch 'linus' into x86/mm, to refresh the branch and pick up fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Cross-merge networking fixes after downstream PR.

No conflicts or adjacent changes.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Merge drm/drm-fixes into drm-misc-fixes

Sima needs a more recent release to apply a patch.

Signed-off-by: Maxime Ripard <mripard@kernel.org>

Merge branch 'master' into mm-hotfixes-stable

Merge tag 'asoc-fix-v6.8-rc2-2' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v6.8

This pull request adds Richard Fitzgerald's series with extensiv

Merge tag 'asoc-fix-v6.8-rc2-2' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v6.8

This pull request adds Richard Fitzgerald's series with extensive fixes
for the CS35L56, he said:

These patches fix various things that were undocumented, unknown or
uncertain when the original driver code was written. And also a few
things that were just bugs.

show more ...

ALSA: Various fixes for Cirrus Logic CS35L56 support

Merge series from Richard Fitzgerald <rf@opensource.cirrus.com>:

These patches fixe various things that were undocumented, unknown or
uncertain

ALSA: Various fixes for Cirrus Logic CS35L56 support

Merge series from Richard Fitzgerald <rf@opensource.cirrus.com>:

These patches fixe various things that were undocumented, unknown or
uncertain when the original driver code was written. And also a few
things that were just bugs.

show more ...

Merge branch 'master' into mm-hotfixes-stable

Merge v6.8-rc1 into drm-misc-fixes

Let's kickstart the 6.8 fix cycle.

Signed-off-by: Maxime Ripard <mripard@kernel.org>

Merge tag 'for-6.8-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

- zoned mode fixes:
- fix slowdown when writing large file sequent

Merge tag 'for-6.8-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

- zoned mode fixes:
- fix slowdown when writing large file sequentially by looking up
block groups with enough space faster
- locking fixes when activating a zone

- new mount API fixes:
- preserve mount options for a ro/rw mount of the same subvolume

- scrub fixes:
- fix use-after-free in case the chunk length is not aligned to
64K, this does not happen normally but has been reported on
images converted from ext4
- similar alignment check was missing with raid-stripe-tree

- subvolume deletion fixes:
- prevent calling ioctl on already deleted subvolume
- properly track flag tracking a deleted subvolume

- in subpage mode, fix decompression of an inline extent (zlib, lzo,
zstd)

- fix crash when starting writeback on a folio, after integration with
recent MM changes this needs to be started conditionally

- reject unknown flags in defrag ioctl

- error handling, API fixes, minor warning fixes

* tag 'for-6.8-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: scrub: limit RST scrub to chunk boundary
btrfs: scrub: avoid use-after-free when chunk length is not 64K aligned
btrfs: don't unconditionally call folio_start_writeback in subpage
btrfs: use the original mount's mount options for the legacy reconfigure
btrfs: don't warn if discard range is not aligned to sector
btrfs: tree-checker: fix inline ref size in error messages
btrfs: zstd: fix and simplify the inline extent decompression
btrfs: lzo: fix and simplify the inline extent decompression
btrfs: zlib: fix and simplify the inline extent decompression
btrfs: defrag: reject unknown flags of btrfs_ioctl_defrag_range_args
btrfs: avoid copying BTRFS_ROOT_SUBVOL_DEAD flag to snapshot of subvolume being deleted
btrfs: don't abort filesystem when attempting to snapshot deleted subvolume
btrfs: zoned: fix lock ordering in btrfs_zone_activate()
btrfs: fix unbalanced unlock of mapping_tree_lock
btrfs: ref-verify: free ref cache before clearing mount opt
btrfs: fix kvcalloc() arguments order in btrfs_ioctl_send()
btrfs: zoned: optimize hint byte for zoned allocator
btrfs: zoned: factor out prepare_allocation_zoned()

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btrfs: zlib: fix and simplify the inline extent decompression

[BUG]

If we have a filesystem with 4k sectorsize, and an inlined compressed
extent created like this:

item 4 key (257 INODE_ITEM 0) i

btrfs: zlib: fix and simplify the inline extent decompression

[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 1 (zlib)

Which has an inline compressed extent at file offset 0, and its
decompressed size is 4K, allowing us to reflink that 4K range to another
location (which will not be compressed).

If we do such reflink on a subpage system, it would fail like this:

# xfs_io -f -c "reflink $mnt/source_inlined 0 60k 4k" $mnt/dest
XFS_IOC_CLONE_RANGE: Input/output error

[CAUSE]
In zlib_decompress(), we didn't treat @start_byte as just a page offset,
but also use it as an indicator on whether we should switch our output
buffer.

In reality, for subpage cases, although @start_byte can be non-zero,
we should never switch input/output buffer, since the whole input/output
buffer should never exceed one sector.

Note: The above assumption is only not true if we're going to support
multi-page sectorsize.

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 modifications:

- Rename @start_byte to @dest_pgoff to properly express its meaning

- Add an extra ASSERT() inside btrfs_decompress() to make sure the
input/output size never exceeds one sector.

- Use Z_FINISH flag to make sure the decompression happens in one go

- Remove the loop needed to switch input/output buffers

- Use correct destination offset inside the destination page

- 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 resulted a 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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Merge remote-tracking branch 'torvalds/master' into perf-tools-next

To pick up fixes that went thru perf-tools for v6.7 and to get in sync
with upstream to check for drift in the copies of headers,

Merge remote-tracking branch 'torvalds/master' into perf-tools-next

To pick up fixes that went thru perf-tools for v6.7 and to get in sync
with upstream to check for drift in the copies of headers, etc.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

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Merge drm/drm-next into drm-misc-next

Let's kickstart the v6.8 release cycle.

Signed-off-by: Maxime Ripard <mripard@kernel.org>

Merge tag 'for-6.8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs updates from David Sterba:
"There are no exciting changes for users, it's been mostly API
conversio

Merge tag 'for-6.8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs updates from David Sterba:
"There are no exciting changes for users, it's been mostly API
conversions and some fixes or refactoring.

The mount API conversion is a base for future improvements that would
come with VFS. Metadata processing has been converted to folios, not
yet enabling the large folios but it's one patch away once everything
gets tested enough.

Core changes:

- convert extent buffers to folios:
- direct API conversion where possible
- performance can drop by a few percent on metadata heavy
workloads, the folio sizes are not constant and the calculations
add up in the item helpers
- both regular and subpage modes
- data cannot be converted yet, we need to port that to iomap and
there are some other generic changes required

- convert mount to the new API, should not be user visible:
- options deprecated long time ago have been removed: inode_cache,
recovery
- the new logic that splits mount to two phases slightly changes
timing of device scanning for multi-device filesystems
- LSM options will now work (like for selinux)

- convert delayed nodes radix tree to xarray, preserving the
preload-like logic that still allows to allocate with GFP_NOFS

- more validation of sysfs value of scrub_speed_max

- refactor chunk map structure, reduce size and improve performance

- extent map refactoring, smaller data structures, improved
performance

- reduce size of struct extent_io_tree, embedded in several
structures

- temporary pages used for compression are cached and attached to a
shrinker, this may slightly improve performance

- in zoned mode, remove redirty extent buffer tracking, zeros are
written in case an out-of-order is detected and proper data are
written to the actual write pointer

- cleanups, refactoring, error message improvements, updated tests

- verify and update branch name or tag

- remove unwanted text"

* tag 'for-6.8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (89 commits)
btrfs: pass btrfs_io_geometry into btrfs_max_io_len
btrfs: pass struct btrfs_io_geometry to set_io_stripe
btrfs: open code set_io_stripe for RAID56
btrfs: change block mapping to switch/case in btrfs_map_block
btrfs: factor out block mapping for single profiles
btrfs: factor out block mapping for RAID5/6
btrfs: reduce scope of data_stripes in btrfs_map_block
btrfs: factor out block mapping for RAID10
btrfs: factor out block mapping for DUP profiles
btrfs: factor out RAID1 block mapping
btrfs: factor out block-mapping for RAID0
btrfs: re-introduce struct btrfs_io_geometry
btrfs: factor out helper for single device IO check
btrfs: migrate btrfs_repair_io_failure() to folio interfaces
btrfs: migrate eb_bitmap_offset() to folio interfaces
btrfs: migrate various end io functions to folios
btrfs: migrate subpage code to folio interfaces
btrfs: migrate get_eb_page_index() and get_eb_offset_in_page() to folios
btrfs: don't double put our subpage reference in alloc_extent_buffer
btrfs: cleanup metadata page pointer usage
...

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btrfs: migrate various end io functions to folios

If we still go the old page based iterator functions, like
bio_for_each_segment_all(), we can hit middle pages of a folio (compound
page).

In that

btrfs: migrate various end io functions to folios

If we still go the old page based iterator functions, like
bio_for_each_segment_all(), we can hit middle pages of a folio (compound
page).

In that case if we set any page flag on those middle pages, we can
easily trigger VM_BUG_ON(), as for compound page flags, they should
follow their flag policies (normally only set on leading or tail pages).

To avoid such problem in the future full folio migration, here we do:

- Change from bio_for_each_segment_all() to bio_for_each_folio_all()
This completely removes the ability to access the middle page.

- Add extra ASSERT()s for data read/write paths
To ensure we only get single paged folio for data now.

- Rename those end io functions to follow a certain schema
* end_bbio_compressed_read()
* end_bbio_compressed_write()

These two endio functions don't set any page flags, as they use pages
not mapped to any address space.
They can be very good candidates for higher order folio testing.

And they are shared between compression and encoded IO.

* end_bbio_data_read()
* end_bbio_data_write()
* end_bbio_meta_read()
* end_bbio_meta_write()

The old function names are not unified:
- end_bio_extent_writepage()
- end_bio_extent_readpage()
- extent_buffer_write_end_io()
- extent_buffer_read_end_io()

They share no schema on where the "end_*io" string should be, nor can
be confusing just using "extent_buffer" and "extent" to distinguish
data and metadata paths.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: migrate subpage code to folio interfaces

Although subpage itself is conflicting with higher folio, since subpage
(sectorsize < PAGE_SIZE and nodesize < PAGE_SIZE) means we will never
need hig

btrfs: migrate subpage code to folio interfaces

Although subpage itself is conflicting with higher folio, since subpage
(sectorsize < PAGE_SIZE and nodesize < PAGE_SIZE) means we will never
need higher order folio, there is a hidden pitfall:

- btrfs_page_*() helpers

Those helpers are an abstraction to handle both subpage and non-subpage
cases, which means we're going to pass pages pointers to those helpers.

And since those helpers are shared between data and metadata paths, it's
unavoidable to let them to handle folios, including higher order
folios).

Meanwhile for true subpage case, we should only have a single page
backed folios anyway, thus add a new ASSERT() for btrfs_subpage_assert()
to ensure that.

Also since those helpers are shared between both data and metadata, add
some extra ASSERT()s for data path to make sure we only get single page
backed folio for now.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: refactor alloc_extent_buffer() to allocate-then-attach method

Currently alloc_extent_buffer() utilizes find_or_create_page() to
allocate one page a time for an extent buffer.

This method has

btrfs: refactor alloc_extent_buffer() to allocate-then-attach method

Currently alloc_extent_buffer() utilizes find_or_create_page() to
allocate one page a time for an extent buffer.

This method has the following disadvantages:

- find_or_create_page() is the legacy way of allocating new pages
With the new folio infrastructure, find_or_create_page() is just
redirected to filemap_get_folio().

- Lacks the way to support higher order (order >= 1) folios
As we can not yet let filemap give us a higher order folio.

This patch would change the workflow by the following way:

Old | new
-----------------------------------+-------------------------------------
| ret = btrfs_alloc_page_array();
for (i = 0; i < num_pages; i++) { | for (i = 0; i < num_pages; i++) {
p = find_or_create_page(); | ret = filemap_add_folio();
/* Attach page private */ | /* Reuse page cache if needed */
/* Reused eb if needed */ |
| /* Attach page private and
| reuse eb if needed */
| }

By this we split the page allocation and private attaching into two
parts, allowing future updates to each part more easily, and migrate to
folio interfaces (especially for possible higher order folios).

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: use the flags of an extent map to identify the compression type

Currently, in struct extent_map, we use an unsigned int (32 bits) to
identify the compression type of an extent and an unsigned

btrfs: use the flags of an extent map to identify the compression type

Currently, in struct extent_map, we use an unsigned int (32 bits) to
identify the compression type of an extent and an unsigned long (64 bits
on a 64 bits platform, 32 bits otherwise) for flags. We are only using
6 different flags, so an unsigned long is excessive and we can use flags
to identify the compression type instead of using a dedicated 32 bits
field.

We can easily have tens or hundreds of thousands (or more) of extent maps
on busy and large filesystems, specially with compression enabled or many
or large files with tons of small extents. So it's convenient to have the
extent_map structure as small as possible in order to use less memory.

So remove the compression type field from struct extent_map, use flags
to identify the compression type and shorten the flags field from an
unsigned long to a u32. This saves 8 bytes (on 64 bits platforms) and
reduces the size of the structure from 136 bytes down to 128 bytes, using
now only two cache lines, and increases the number of extent maps we can
have per 4K page from 30 to 32. By using a u32 for the flags instead of
an unsigned long, we no longer use test_bit(), set_bit() and clear_bit(),
but that level of atomicity is not needed as most flags are never cleared
once set (before adding an extent map to the tree), and the ones that can
be cleared or set after an extent map is added to the tree, are always
performed while holding the write lock on the extent map tree, while the
reader holds a lock on the tree or tests for a flag that never changes
once the extent map is in the tree (such as compression flags).

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: use shrinker for compression page pool

The pages are now allocated and freed centrally, so we can extend the
logic to manage the lifetime. The main idea is to keep a few recently
used pages a

btrfs: use shrinker for compression page pool

The pages are now allocated and freed centrally, so we can extend the
logic to manage the lifetime. The main idea is to keep a few recently
used pages and hand them to all writers. Ideally we won't have to go to
allocator at all (a slight performance gain) and also raise chance that
we'll have the pages available (slightly increased reliability).

In order to avoid gathering too many pages, the shrinker is attached to
the cache so we can free them on when MM demands that. The first
implementation will drain the whole cache. Further this can be refined
to keep some minimal number of pages for emergency purposes. The
ultimate goal to avoid memory allocation failures on the write out path
from the compression.

The pool threshold is set to cover full BTRFS_MAX_COMPRESSED / PAGE_SIZE
for minimal thread pool, which is 8 (btrfs_init_fs_info()). This is 128K
/ 4K * 8 = 256 pages at maximum, which is 1MiB.

This is for all filesystems currently mounted, with heavy use of
compression IO the allocator is still needed. The cache helps for short
burst IO.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: use page alloc/free wrappers for compression pages

This is a preparation for managing compression pages in a cache-like
manner, instead of asking the allocator each time. The common allocatio

btrfs: use page alloc/free wrappers for compression pages

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>

show more ...