[PATCH 0/3] btrfs-progs: docs: add entries to sysfs documentation

[PATCH 0/3] btrfs-progs: docs: add entries to sysfs documentation

[Naohiro Aota]

This series adds a description for per-space_info bg_reclaim_threshold
and chunk_size. It also fixes a subtle typo.

Naohiro Aota (3):
  btrfs-progs: docs: add per-space_info bg_reclaim_threshold entry
  btrfs-progs: docs: fix nodesize typo
  btrfs-progs: docs: add chunk_size description

 Documentation/ch-sysfs.rst | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

-- 
2.39.1

[PATCH 1/3] btrfs-progs: docs: add per-space_info bg_reclaim_threshold entry

[Naohiro Aota]

There are two "bg_reclaim_threshold" under the sysfs directory. One is at
/sys/fs/btrfs/<UUID>/ and sets the threshold to start the auto reclaim
thread. The other one is
at/sys/fs/btrfs/<UUID>/allocations/{data,metadata,system} and sets the
threshold to reclaim a block group.

These two options have the same name but they are calculated against
different metrics. The former is a percentage of allocated (for a device
extent) space on total device space, and the latter is a percentage of
reclaimable space on a block group's zone capacity.

Add description for per-space_info bg_reclaim_threshold to distinguish
these two same name configurations.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 Documentation/ch-sysfs.rst | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/Documentation/ch-sysfs.rst b/Documentation/ch-sysfs.rst
index 96fdaa34bff3..37fb49f945c7 100644
--- a/Documentation/ch-sysfs.rst
+++ b/Documentation/ch-sysfs.rst
@@ -29,7 +29,7 @@ Files in `/sys/fs/btrfs/<UUID>/` directory are:
 bg_reclaim_threshold
         (RW, since: 5.19)
 
-        Used space percentage to start auto block group claim.
+        Used space percentage of total device space to start auto block group claim.
         Mostly for zoned devices.
 
 checksum
@@ -117,6 +117,14 @@ global_rsv_size
         Space info accounting for the 3 chunk types.
         Mostly for debug purposes.
 
+Files in `/sys/fs/btrfs/<UUID>/allocations/{data,metadata,system}` directory are:
+
+bg_reclaim_threshold
+        (RW, since: 5.19)
+
+        Reclaimable space percentage of block group's size (excluding permanently unusable space) to reclaim the block group.
+        Used for zoned devices.
+
 Files in `/sys/fs/btrfs/<UUID>/devinfo/<DEVID>` directory are:
 
 error_stats:
-- 
2.39.1

Re: [PATCH 1/3] btrfs-progs: docs: add per-space_info bg_reclaim_threshold entry

[Johannes Thumshirn]

On 18.01.23 09:16, Naohiro Aota wrote:
> +Files in `/sys/fs/btrfs/<UUID>/allocations/{data,metadata,system}` directory are:
> +
> +bg_reclaim_threshold
> +        (RW, since: 5.19)
> +
> +        Reclaimable space percentage of block group's size (excluding permanently unusable space) to reclaim the block group.
> +        Used for zoned devices.

I'd discard the last sentence, as the bg_reclaim_threshold is 
used on non-zoned devices as well.

> +
>  Files in `/sys/fs/btrfs/<UUID>/devinfo/<DEVID>` directory are:

[PATCH 2/3] btrfs-progs: docs: fix nodesize typo

[Naohiro Aota]

Fix the typo.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 Documentation/ch-sysfs.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/ch-sysfs.rst b/Documentation/ch-sysfs.rst
index 37fb49f945c7..569879aadf27 100644
--- a/Documentation/ch-sysfs.rst
+++ b/Documentation/ch-sysfs.rst
@@ -75,7 +75,7 @@ metadata_uuid
         Shows the metadata uuid of the mounted filesystem.
         Check `metadata_uuid` feature for more details.
 
-nodeisze
+nodesize
         (RO, since: 3.14)
 
         Show the nodesize of the mounted filesystem.
-- 
2.39.1

[PATCH 3/3] btrfs-progs: docs: add chunk_size description

[Naohiro Aota]

Add description for /sys/fs/btrfs/<uuid>/allocation/<type>/chunk_size.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 Documentation/ch-sysfs.rst | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/ch-sysfs.rst b/Documentation/ch-sysfs.rst
index 569879aadf27..09e409a41aa5 100644
--- a/Documentation/ch-sysfs.rst
+++ b/Documentation/ch-sysfs.rst
@@ -125,6 +125,12 @@ bg_reclaim_threshold
         Reclaimable space percentage of block group's size (excluding permanently unusable space) to reclaim the block group.
         Used for zoned devices.
 
+chunk_size
+        (RW, since: 6.0)
+
+        Shows the chunk size. Can be changed for data and metadata.
+        Cannot be set for zoned devices.
+
 Files in `/sys/fs/btrfs/<UUID>/devinfo/<DEVID>` directory are:
 
 error_stats:
-- 
2.39.1

Re: [PATCH 0/3] btrfs-progs: docs: add entries to sysfs documentation

[David Sterba]

On Wed, Jan 18, 2023 at 04:44:55PM +0900, Naohiro Aota wrote:
> This series adds a description for per-space_info bg_reclaim_threshold
> and chunk_size. It also fixes a subtle typo.
> 
> Naohiro Aota (3):
>   btrfs-progs: docs: add per-space_info bg_reclaim_threshold entry
>   btrfs-progs: docs: fix nodesize typo
>   btrfs-progs: docs: add chunk_size description

Added to devel, thanks. For the bg_reclaim I've added that it can be
used for regular devices too.