<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-dev/fs/btrfs, branch linus/master</title>
<subtitle>Linux kernel development work - see feature branches</subtitle>
<id>https://git.zx2c4.com/linux-dev/atom/fs/btrfs?h=linus%2Fmaster</id>
<link rel='self' href='https://git.zx2c4.com/linux-dev/atom/fs/btrfs?h=linus%2Fmaster'/>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/'/>
<updated>2022-06-21T17:06:04Z</updated>
<entry>
<title>Merge tag 'for-5.19-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux</title>
<updated>2022-06-21T17:06:04Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-06-21T17:06:04Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=ff872b76b3d89a09a997cc45c133e4a3ddc12f90'/>
<id>urn:sha1:ff872b76b3d89a09a997cc45c133e4a3ddc12f90</id>
<content type='text'>
Pull btrfs fixes from David Sterba:

 - print more error messages for invalid mount option values

 - prevent remount with v1 space cache for subpage filesystem

 - fix hang during unmount when block group reclaim task is running

* tag 'for-5.19-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: add error messages to all unrecognized mount options
  btrfs: prevent remounting to v1 space cache for subpage mount
  btrfs: fix hang during unmount when block group reclaim task is running
</content>
</entry>
<entry>
<title>btrfs: add error messages to all unrecognized mount options</title>
<updated>2022-06-07T15:29:50Z</updated>
<author>
<name>David Sterba</name>
<email>dsterba@suse.com</email>
</author>
<published>2022-06-02T21:57:17Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=e3a4167c880cf889f66887a152799df4d609dd21'/>
<id>urn:sha1:e3a4167c880cf889f66887a152799df4d609dd21</id>
<content type='text'>
Almost none of the errors stemming from a valid mount option but wrong
value prints a descriptive message which would help to identify why
mount failed. Like in the linked report:

  $ uname -r
  v4.19
  $ mount -o compress=zstd /dev/sdb /mnt
  mount: /mnt: wrong fs type, bad option, bad superblock on
  /dev/sdb, missing codepage or helper program, or other error.
  $ dmesg
  ...
  BTRFS error (device sdb): open_ctree failed

Errors caused by memory allocation failures are left out as it's not a
user error so reporting that would be confusing.

Link: https://lore.kernel.org/linux-btrfs/9c3fec36-fc61-3a33-4977-a7e207c3fa4e@gmx.de/
CC: stable@vger.kernel.org # 4.9+
Reviewed-by: Qu Wenruo &lt;wqu@suse.com&gt;
Reviewed-by: Nikolay Borisov &lt;nborisov@suse.com&gt;
Reviewed-by: Anand Jain &lt;anand.jain@oracle.com&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
</content>
</entry>
<entry>
<title>btrfs: prevent remounting to v1 space cache for subpage mount</title>
<updated>2022-06-06T14:18:59Z</updated>
<author>
<name>Qu Wenruo</name>
<email>wqu@suse.com</email>
</author>
<published>2022-05-18T05:03:09Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=0591f04036218d572d54349ea8c7914ad9c82b2b'/>
<id>urn:sha1:0591f04036218d572d54349ea8c7914ad9c82b2b</id>
<content type='text'>
Upstream commit 9f73f1aef98b ("btrfs: force v2 space cache usage for
subpage mount") forces subpage mount to use v2 cache, to avoid
deprecated v1 cache which doesn't support subpage properly.

But there is a loophole that user can still remount to v1 cache.

The existing check will only give users a warning, but does not really
prevent to do the remount.

Although remounting to v1 will not cause any problems since the v1 cache
will always be marked invalid when mounted with a different page size,
it's still better to prevent v1 cache at all for subpage mounts.

Fixes: 9f73f1aef98b ("btrfs: force v2 space cache usage for subpage mount")
CC: stable@vger.kernel.org # 5.15+
Signed-off-by: Qu Wenruo &lt;wqu@suse.com&gt;
Reviewed-by: David Sterba &lt;dsterba@suse.com&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
</content>
</entry>
<entry>
<title>btrfs: fix hang during unmount when block group reclaim task is running</title>
<updated>2022-06-06T14:18:52Z</updated>
<author>
<name>Filipe Manana</name>
<email>fdmanana@suse.com</email>
</author>
<published>2022-05-18T09:41:48Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=31e70e527806c546a72262f2fc3d982ee23c42d3'/>
<id>urn:sha1:31e70e527806c546a72262f2fc3d982ee23c42d3</id>
<content type='text'>
When we start an unmount, at close_ctree(), if we have the reclaim task
running and in the middle of a data block group relocation, we can trigger
a deadlock when stopping an async reclaim task, producing a trace like the
following:

[629724.498185] task:kworker/u16:7   state:D stack:    0 pid:681170 ppid:     2 flags:0x00004000
[629724.499760] Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs]
[629724.501267] Call Trace:
[629724.501759]  &lt;TASK&gt;
[629724.502174]  __schedule+0x3cb/0xed0
[629724.502842]  schedule+0x4e/0xb0
[629724.503447]  btrfs_wait_on_delayed_iputs+0x7c/0xc0 [btrfs]
[629724.504534]  ? prepare_to_wait_exclusive+0xc0/0xc0
[629724.505442]  flush_space+0x423/0x630 [btrfs]
[629724.506296]  ? rcu_read_unlock_trace_special+0x20/0x50
[629724.507259]  ? lock_release+0x220/0x4a0
[629724.507932]  ? btrfs_get_alloc_profile+0xb3/0x290 [btrfs]
[629724.508940]  ? do_raw_spin_unlock+0x4b/0xa0
[629724.509688]  btrfs_async_reclaim_metadata_space+0x139/0x320 [btrfs]
[629724.510922]  process_one_work+0x252/0x5a0
[629724.511694]  ? process_one_work+0x5a0/0x5a0
[629724.512508]  worker_thread+0x52/0x3b0
[629724.513220]  ? process_one_work+0x5a0/0x5a0
[629724.514021]  kthread+0xf2/0x120
[629724.514627]  ? kthread_complete_and_exit+0x20/0x20
[629724.515526]  ret_from_fork+0x22/0x30
[629724.516236]  &lt;/TASK&gt;
[629724.516694] task:umount          state:D stack:    0 pid:719055 ppid:695412 flags:0x00004000
[629724.518269] Call Trace:
[629724.518746]  &lt;TASK&gt;
[629724.519160]  __schedule+0x3cb/0xed0
[629724.519835]  schedule+0x4e/0xb0
[629724.520467]  schedule_timeout+0xed/0x130
[629724.521221]  ? lock_release+0x220/0x4a0
[629724.521946]  ? lock_acquired+0x19c/0x420
[629724.522662]  ? trace_hardirqs_on+0x1b/0xe0
[629724.523411]  __wait_for_common+0xaf/0x1f0
[629724.524189]  ? usleep_range_state+0xb0/0xb0
[629724.524997]  __flush_work+0x26d/0x530
[629724.525698]  ? flush_workqueue_prep_pwqs+0x140/0x140
[629724.526580]  ? lock_acquire+0x1a0/0x310
[629724.527324]  __cancel_work_timer+0x137/0x1c0
[629724.528190]  close_ctree+0xfd/0x531 [btrfs]
[629724.529000]  ? evict_inodes+0x166/0x1c0
[629724.529510]  generic_shutdown_super+0x74/0x120
[629724.530103]  kill_anon_super+0x14/0x30
[629724.530611]  btrfs_kill_super+0x12/0x20 [btrfs]
[629724.531246]  deactivate_locked_super+0x31/0xa0
[629724.531817]  cleanup_mnt+0x147/0x1c0
[629724.532319]  task_work_run+0x5c/0xa0
[629724.532984]  exit_to_user_mode_prepare+0x1a6/0x1b0
[629724.533598]  syscall_exit_to_user_mode+0x16/0x40
[629724.534200]  do_syscall_64+0x48/0x90
[629724.534667]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[629724.535318] RIP: 0033:0x7fa2b90437a7
[629724.535804] RSP: 002b:00007ffe0b7e4458 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
[629724.536912] RAX: 0000000000000000 RBX: 00007fa2b9182264 RCX: 00007fa2b90437a7
[629724.538156] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000555d6cf20dd0
[629724.539053] RBP: 0000555d6cf20ba0 R08: 0000000000000000 R09: 00007ffe0b7e3200
[629724.539956] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
[629724.540883] R13: 0000555d6cf20dd0 R14: 0000555d6cf20cb0 R15: 0000000000000000
[629724.541796]  &lt;/TASK&gt;

This happens because:

1) Before entering close_ctree() we have the async block group reclaim
   task running and relocating a data block group;

2) There's an async metadata (or data) space reclaim task running;

3) We enter close_ctree() and park the cleaner kthread;

4) The async space reclaim task is at flush_space() and runs all the
   existing delayed iputs;

5) Before the async space reclaim task calls
   btrfs_wait_on_delayed_iputs(), the block group reclaim task which is
   doing the data block group relocation, creates a delayed iput at
   replace_file_extents() (called when COWing leaves that have file extent
   items pointing to relocated data extents, during the merging phase
   of relocation roots);

6) The async reclaim space reclaim task blocks at
   btrfs_wait_on_delayed_iputs(), since we have a new delayed iput;

7) The task at close_ctree() then calls cancel_work_sync() to stop the
   async space reclaim task, but it blocks since that task is waiting for
   the delayed iput to be run;

8) The delayed iput is never run because the cleaner kthread is parked,
   and no one else runs delayed iputs, resulting in a hang.

So fix this by stopping the async block group reclaim task before we
park the cleaner kthread.

Fixes: 18bb8bbf13c183 ("btrfs: zoned: automatically reclaim zones")
CC: stable@vger.kernel.org # 5.15+
Signed-off-by: Filipe Manana &lt;fdmanana@suse.com&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
</content>
</entry>
<entry>
<title>Merge tag 'folio-5.19' of git://git.infradead.org/users/willy/pagecache</title>
<updated>2022-05-25T02:55:07Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-05-25T02:55:07Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=fdaf9a5840acaab18694a19e0eb0aa51162eeeed'/>
<id>urn:sha1:fdaf9a5840acaab18694a19e0eb0aa51162eeeed</id>
<content type='text'>
Pull page cache updates from Matthew Wilcox:

 - Appoint myself page cache maintainer

 - Fix how scsicam uses the page cache

 - Use the memalloc_nofs_save() API to replace AOP_FLAG_NOFS

 - Remove the AOP flags entirely

 - Remove pagecache_write_begin() and pagecache_write_end()

 - Documentation updates

 - Convert several address_space operations to use folios:
     - is_dirty_writeback
     - readpage becomes read_folio
     - releasepage becomes release_folio
     - freepage becomes free_folio

 - Change filler_t to require a struct file pointer be the first
   argument like -&gt;read_folio

* tag 'folio-5.19' of git://git.infradead.org/users/willy/pagecache: (107 commits)
  nilfs2: Fix some kernel-doc comments
  Appoint myself page cache maintainer
  fs: Remove aops-&gt;freepage
  secretmem: Convert to free_folio
  nfs: Convert to free_folio
  orangefs: Convert to free_folio
  fs: Add free_folio address space operation
  fs: Convert drop_buffers() to use a folio
  fs: Change try_to_free_buffers() to take a folio
  jbd2: Convert release_buffer_page() to use a folio
  jbd2: Convert jbd2_journal_try_to_free_buffers to take a folio
  reiserfs: Convert release_buffer_page() to use a folio
  fs: Remove last vestiges of releasepage
  ubifs: Convert to release_folio
  reiserfs: Convert to release_folio
  orangefs: Convert to release_folio
  ocfs2: Convert to release_folio
  nilfs2: Remove comment about releasepage
  nfs: Convert to release_folio
  jfs: Convert to release_folio
  ...
</content>
</entry>
<entry>
<title>Merge tag 'for-5.19-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux</title>
<updated>2022-05-25T01:52:35Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-05-25T01:52:35Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=bd1b7c1384ec15294ee45bf3add7b7036e146dad'/>
<id>urn:sha1:bd1b7c1384ec15294ee45bf3add7b7036e146dad</id>
<content type='text'>
Pull btrfs updates from David Sterba:
 "Features:

   - subpage:
      - support for PAGE_SIZE &gt; 4K (previously only 64K)
      - make it work with raid56

   - repair super block num_devices automatically if it does not match
     the number of device items

   - defrag can convert inline extents to regular extents, up to now
     inline files were skipped but the setting of mount option
     max_inline could affect the decision logic

   - zoned:
      - minimal accepted zone size is explicitly set to 4MiB
      - make zone reclaim less aggressive and don't reclaim if there are
        enough free zones
      - add per-profile sysfs tunable of the reclaim threshold

   - allow automatic block group reclaim for non-zoned filesystems, with
     sysfs tunables

   - tree-checker: new check, compare extent buffer owner against owner
     rootid

  Performance:

   - avoid blocking on space reservation when doing nowait direct io
     writes (+7% throughput for reads and writes)

   - NOCOW write throughput improvement due to refined locking (+3%)

   - send: reduce pressure to page cache by dropping extent pages right
     after they're processed

  Core:

   - convert all radix trees to xarray

   - add iterators for b-tree node items

   - support printk message index

   - user bulk page allocation for extent buffers

   - switch to bio_alloc API, use on-stack bios where convenient, other
     bio cleanups

   - use rw lock for block groups to favor concurrent reads

   - simplify workques, don't allocate high priority threads for all
     normal queues as we need only one

   - refactor scrub, process chunks based on their constraints and
     similarity

   - allocate direct io structures on stack and pass around only
     pointers, avoids allocation and reduces potential error handling

  Fixes:

   - fix count of reserved transaction items for various inode
     operations

   - fix deadlock between concurrent dio writes when low on free data
     space

   - fix a few cases when zones need to be finished

  VFS, iomap:

   - add helper to check if sb write has started (usable for assertions)

   - new helper iomap_dio_alloc_bio, export iomap_dio_bio_end_io"

* tag 'for-5.19-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (173 commits)
  btrfs: zoned: introduce a minimal zone size 4M and reject mount
  btrfs: allow defrag to convert inline extents to regular extents
  btrfs: add "0x" prefix for unsupported optional features
  btrfs: do not account twice for inode ref when reserving metadata units
  btrfs: zoned: fix comparison of alloc_offset vs meta_write_pointer
  btrfs: send: avoid trashing the page cache
  btrfs: send: keep the current inode open while processing it
  btrfs: allocate the btrfs_dio_private as part of the iomap dio bio
  btrfs: move struct btrfs_dio_private to inode.c
  btrfs: remove the disk_bytenr in struct btrfs_dio_private
  btrfs: allocate dio_data on stack
  iomap: add per-iomap_iter private data
  iomap: allow the file system to provide a bio_set for direct I/O
  btrfs: add a btrfs_dio_rw wrapper
  btrfs: zoned: zone finish unused block group
  btrfs: zoned: properly finish block group on metadata write
  btrfs: zoned: finish block group when there are no more allocatable bytes left
  btrfs: zoned: consolidate zone finish functions
  btrfs: zoned: introduce btrfs_zoned_bg_is_full
  btrfs: improve error reporting in lookup_inline_extent_backref
  ...
</content>
</entry>
<entry>
<title>Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux</title>
<updated>2022-05-24T04:06:11Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-05-24T04:06:11Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=143a6252e1b8ab424b4b293512a97cca7295c182'/>
<id>urn:sha1:143a6252e1b8ab424b4b293512a97cca7295c182</id>
<content type='text'>
Pull arm64 updates from Catalin Marinas:

 - Initial support for the ARMv9 Scalable Matrix Extension (SME).

   SME takes the approach used for vectors in SVE and extends this to
   provide architectural support for matrix operations. No KVM support
   yet, SME is disabled in guests.

 - Support for crashkernel reservations above ZONE_DMA via the
   'crashkernel=X,high' command line option.

 - btrfs search_ioctl() fix for live-lock with sub-page faults.

 - arm64 perf updates: support for the Hisilicon "CPA" PMU for
   monitoring coherent I/O traffic, support for Arm's CMN-650 and
   CMN-700 interconnect PMUs, minor driver fixes, kerneldoc cleanup.

 - Kselftest updates for SME, BTI, MTE.

 - Automatic generation of the system register macros from a 'sysreg'
   file describing the register bitfields.

 - Update the type of the function argument holding the ESR_ELx register
   value to unsigned long to match the architecture register size
   (originally 32-bit but extended since ARMv8.0).

 - stacktrace cleanups.

 - ftrace cleanups.

 - Miscellaneous updates, most notably: arm64-specific huge_ptep_get(),
   avoid executable mappings in kexec/hibernate code, drop TLB flushing
   from get_clear_flush() (and rename it to get_clear_contig()),
   ARCH_NR_GPIO bumped to 2048 for ARCH_APPLE.

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (145 commits)
  arm64/sysreg: Generate definitions for FAR_ELx
  arm64/sysreg: Generate definitions for DACR32_EL2
  arm64/sysreg: Generate definitions for CSSELR_EL1
  arm64/sysreg: Generate definitions for CPACR_ELx
  arm64/sysreg: Generate definitions for CONTEXTIDR_ELx
  arm64/sysreg: Generate definitions for CLIDR_EL1
  arm64/sve: Move sve_free() into SVE code section
  arm64: Kconfig.platforms: Add comments
  arm64: Kconfig: Fix indentation and add comments
  arm64: mm: avoid writable executable mappings in kexec/hibernate code
  arm64: lds: move special code sections out of kernel exec segment
  arm64/hugetlb: Implement arm64 specific huge_ptep_get()
  arm64/hugetlb: Use ptep_get() to get the pte value of a huge page
  arm64: kdump: Do not allocate crash low memory if not needed
  arm64/sve: Generate ZCR definitions
  arm64/sme: Generate defintions for SVCR
  arm64/sme: Generate SMPRI_EL1 definitions
  arm64/sme: Automatically generate SMPRIMAP_EL2 definitions
  arm64/sme: Automatically generate SMIDR_EL1 defines
  arm64/sme: Automatically generate defines for SMCR
  ...
</content>
</entry>
<entry>
<title>Merge tag 'for-5.19/block-2022-05-22' of git://git.kernel.dk/linux-block</title>
<updated>2022-05-23T20:56:39Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-05-23T20:56:39Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=115cd47132d71bd7e4aa1093e15d861a59e73a94'/>
<id>urn:sha1:115cd47132d71bd7e4aa1093e15d861a59e73a94</id>
<content type='text'>
Pull block updates from Jens Axboe:
 "Here are the core block changes for 5.19. This contains:

   - blk-throttle accounting fix (Laibin)

   - Series removing redundant assignments (Michal)

   - Expose bio cache via the bio_set, so that DM can use it (Mike)

   - Finish off the bio allocation interface cleanups by dealing with
     the weirdest member of the family. bio_kmalloc combines a kmalloc
     for the bio and bio_vecs with a hidden bio_init call and magic
     cleanup semantics (Christoph)

   - Clean up the block layer API so that APIs consumed by file systems
     are (almost) only struct block_device based, so that file systems
     don't have to poke into block layer internals like the
     request_queue (Christoph)

   - Clean up the blk_execute_rq* API (Christoph)

   - Clean up various lose end in the blk-cgroup code to make it easier
     to follow in preparation of reworking the blkcg assignment for bios
     (Christoph)

   - Fix use-after-free issues in BFQ when processes with merged queues
     get moved to different cgroups (Jan)

   - BFQ fixes (Jan)

   - Various fixes and cleanups (Bart, Chengming, Fanjun, Julia, Ming,
     Wolfgang, me)"

* tag 'for-5.19/block-2022-05-22' of git://git.kernel.dk/linux-block: (83 commits)
  blk-mq: fix typo in comment
  bfq: Remove bfq_requeue_request_body()
  bfq: Remove superfluous conversion from RQ_BIC()
  bfq: Allow current waker to defend against a tentative one
  bfq: Relax waker detection for shared queues
  blk-cgroup: delete rcu_read_lock_held() WARN_ON_ONCE()
  blk-throttle: Set BIO_THROTTLED when bio has been throttled
  blk-cgroup: Remove unnecessary rcu_read_lock/unlock()
  blk-cgroup: always terminate io.stat lines
  block, bfq: make bfq_has_work() more accurate
  block, bfq: protect 'bfqd-&gt;queued' by 'bfqd-&gt;lock'
  block: cleanup the VM accounting in submit_bio
  block: Fix the bio.bi_opf comment
  block: reorder the REQ_ flags
  blk-iocost: combine local_stat and desc_stat to stat
  block: improve the error message from bio_check_eod
  block: allow passing a NULL bdev to bio_alloc_clone/bio_init_clone
  block: remove superfluous calls to blkcg_bio_issue_init
  kthread: unexport kthread_blkcg
  blk-cgroup: cleanup blkcg_maybe_throttle_current
  ...
</content>
</entry>
<entry>
<title>btrfs: zoned: introduce a minimal zone size 4M and reject mount</title>
<updated>2022-05-17T18:15:25Z</updated>
<author>
<name>Johannes Thumshirn</name>
<email>johannes.thumshirn@wdc.com</email>
</author>
<published>2022-05-13T15:52:52Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=0a05fafe9def0d9f0fbef3dfc8094925af9e3185'/>
<id>urn:sha1:0a05fafe9def0d9f0fbef3dfc8094925af9e3185</id>
<content type='text'>
Zoned devices are expected to have zone sizes in the range of 1-2GB for
ZNS SSDs and SMR HDDs have zone sizes of 256MB, so there is no need to
allow arbitrarily small zone sizes on btrfs.

But for testing purposes with emulated devices it is sometimes desirable
to create devices with as small as 4MB zone size to uncover errors.

So use 4MB as the smallest possible zone size and reject mounts of devices
with a smaller zone size.

Reviewed-by: Nikolay Borisov &lt;nborisov@suse.com&gt;
Signed-off-by: Johannes Thumshirn &lt;johannes.thumshirn@wdc.com&gt;
Reviewed-by: David Sterba &lt;dsterba@suse.com&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
</content>
</entry>
<entry>
<title>btrfs: allow defrag to convert inline extents to regular extents</title>
<updated>2022-05-17T18:15:25Z</updated>
<author>
<name>Qu Wenruo</name>
<email>wqu@suse.com</email>
</author>
<published>2022-05-09T12:00:53Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=d8101a0c8a318d1c25f333f44523571806b3fb05'/>
<id>urn:sha1:d8101a0c8a318d1c25f333f44523571806b3fb05</id>
<content type='text'>
Btrfs defaults to max_inline=2K to make small writes inlined into
metadata.

The default value is always a win, as even DUP/RAID1/RAID10 doubles the
metadata usage, it should still cause less physical space used compared
to a 4K regular extents.

But since the introduction of RAID1C3 and RAID1C4 it's no longer the case,
users may find inlined extents causing too much space wasted, and want
to convert those inlined extents back to regular extents.

Unfortunately defrag will unconditionally skip all inline extents, no
matter if the user is trying to converting them back to regular extents.

So this patch will add a small exception for defrag_collect_targets() to
allow defragging inline extents, if and only if the inlined extents are
larger than max_inline, allowing users to convert them to regular ones.

This also allows us to defrag extents like the following:

	item 6 key (257 EXTENT_DATA 0) itemoff 15794 itemsize 69
		generation 7 type 0 (inline)
		inline extent data size 48 ram_bytes 4096 compression 1 (zlib)
	item 7 key (257 EXTENT_DATA 4096) itemoff 15741 itemsize 53
		generation 7 type 1 (regular)
		extent data disk byte 13631488 nr 4096
		extent data offset 0 nr 16384 ram 16384
		extent compression 1 (zlib)

Previously we're unable to do any defrag, since the first extent is
inlined, and the second one has no extent to merge.

Now we can defrag it to just one single extent, saving 48 bytes metadata
space.

	item 6 key (257 EXTENT_DATA 0) itemoff 15810 itemsize 53
		generation 8 type 1 (regular)
		extent data disk byte 13635584 nr 4096
		extent data offset 0 nr 20480 ram 20480
		extent compression 1 (zlib)

Reviewed-by: Filipe Manana &lt;fdmanana@suse.com&gt;
Signed-off-by: Qu Wenruo &lt;wqu@suse.com&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
</content>
</entry>
</feed>
