kdave · loemraw · May 25, 2025 · Jul 18, 2025 · Jul 18, 2025 · Mar 20, 2025
diff --git a/.github/workflows/ci-build-test.yml b/.github/workflows/ci-build-test.yml
@@ -14,12 +14,6 @@ on:
       - release-test
       - master
 jobs:
-  check-centos7:
-    name: CI Centos 7
-    runs-on: ubuntu-24.04
-    steps:
-      - name: CI Centos7
-        run: sudo docker run kdave/ci-centos-7-x86_64 ./test-build $GITHUB_REF_NAME --disable-documentation --disable-libudev
   check-centos8:
     name: CI Centos 8
     runs-on: ubuntu-24.04

diff --git a/Documentation/Contributors.rst b/Documentation/Contributors.rst
@@ -60,6 +60,7 @@ Statistics for 6.x series
     "6.13", "25", "112756", "164722", "156", "+2780 -1579", 2025
     "6.14", "20", "114592", "167178", "147", "+3847 -1391"
     "6.15", "25", "114616", "167485", "190", "+2346 -2039"
+    "6.16", "16", "114997", "168152", "222", "+4143 -3464"
 
 
 Legend:

diff --git a/Documentation/Kernel-by-version.rst b/Documentation/Kernel-by-version.rst
diff --git a/Documentation/btrfs-filesystem.rst b/Documentation/btrfs-filesystem.rst
@@ -124,6 +124,8 @@ defragment [options] <file>|<dir> [<file>|<dir>...]
                 1..9, *lzo* does not have any levels, *zstd* the standard levels 1..15 and also the
                 realtime -1..-15.
 
+        --nocomp
+                Do not compress while defragmenting, uncompress extents if needed.
         -r
                 defragment files recursively in given directories, does not descend to
                 subvolumes or mount points

diff --git a/Documentation/btrfs-qgroup.rst b/Documentation/btrfs-qgroup.rst
@@ -13,11 +13,7 @@ DESCRIPTION
 
 .. note::
    To use qgroup you need to enable quota first using :command:`btrfs quota enable`
-   command.
-
-.. warning::
-   Qgroup is not stable yet and will impact performance in current mainline
-   kernel (v4.14).
+   command, see :doc:`btrfs-quota`.
 
 QGROUP
 ------
@@ -26,10 +22,10 @@ Quota groups or qgroup in btrfs make a tree hierarchy, the leaf qgroups are
 attached to subvolumes. The size limits are set per qgroup and apply when any
 limit is reached in tree that contains a given subvolume.
 
-The limits are separated between shared and exclusive and reflect the extent
+The limits are separated between *shared* and *exclusive* and reflect the extent
 ownership. For example a fresh snapshot shares almost all the blocks with the
 original subvolume, new writes to either subvolume will raise towards the
-exclusive limit.
+exclusive limit. Extent sharing is also result of *reflink* or *deduplication*.
 
 .. note::
    Qgroup limit only works when qgroup is in a consistent state.
@@ -40,11 +36,12 @@ exclusive limit.
 The qgroup identifiers conform to *level/id* where level 0 is reserved to the
 qgroups associated with subvolumes. Such qgroups are created automatically.
 
-The qgroup hierarchy is built by commands :command:`create` and :command:`assign`.
+The qgroup hierarchy is built by commands :command:`btrfs qgroup create` and
+:command:`btrfs qgroup assign`.
 
 .. note::
-   If the qgroup of a subvolume is destroyed, quota about the subvolume will
-   not be functional until qgroup *0/<subvolume id>* is created again.
+   If the qgroup of a subvolume is destroyed, quota related to the subvolume
+   will not be functional until qgroup *0/<subvolume id>* is created again.
 
 SUBCOMMAND
 ----------
@@ -78,8 +75,9 @@ destroy <qgroupid> <path>
 
 clear-stale <path>
 	Clear all stale qgroups whose subvolume does not exist anymore, this is the
-	level 0 qgroup like 0/subvolid. Higher level qgroups are not deleted even
-	if they don't have any child qgroups.
+	level 0 qgroup like *0/subvolid*. Higher level qgroups are not deleted even
+        if they don't have any child qgroups as they are always created by the
+        user and their deletion should be verified first.
 
 limit [options] <size>|none [<qgroupid>] <path>
         Limit the size of a qgroup to *size* or no limit in the btrfs filesystem
@@ -161,21 +159,21 @@ show [options] <path>
 
 SPECIAL PATHS
 -------------
-For `btrfs qgroup show` subcommand, the ``path`` column may has some special
-strings:
+For :command:`btrfs qgroup show` command, the :file:`path` column can print
+special values:
 
 `<toplevel>`
-	The toplevel subvolume
+	The toplevel subvolume.
 
 `<under deletion>`
-        The subvolume has been deleted (it's directory removed), but the
+        The subvolume has been deleted (its directory removed), but the
         subvolume metadata not not yet fully cleaned.
 
 `<squota space holder>`
-	For simple quota mode only.
+	For *simple quota* mode only.
 	By its design, a fully deleted subvolume may still have accounting on
-	it, so even the subvolume is gone, the numbers are still here for future
-	accounting.
+        it, so even if the subvolume is gone, the numbers are still here for
+        future accounting.
 
 `<stale>`
 	The qgroup has no corresponding subvolume anymore, and the qgroup
@@ -190,7 +188,7 @@ QUOTA RESCAN
 The rescan reads all extent sharing metadata and updates the respective qgroups
 accordingly.
 
-The information consists of bytes owned exclusively (*excl*) or shared/referred
+The information consists of bytes owned exclusively (*excl*) or shared/referenced
 to (*rfer*). There's no explicit information about which extents are shared or
 owned exclusively.  This means when qgroup relationship changes, extent owners
 change and qgroup numbers are no longer consistent unless we do a full rescan.

diff --git a/Documentation/btrfs-quota.rst b/Documentation/btrfs-quota.rst
@@ -19,21 +19,16 @@ of a btrfs filesystem. The quota groups (qgroups) are managed by the subcommand
         :ref:`HIERARCHICAL QUOTA GROUP CONCEPTS<man-quota-hierarchical-quota-group-concepts>`
         for a detailed description.
 
-PERFORMANCE IMPLICATIONS
-^^^^^^^^^^^^^^^^^^^^^^^^
+STABILITY AND PERFORMANCE IMPLICATIONS
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The qgroup implementation is considered reasonably stable for daily use and has
+been enabled in various distributions.
 
 When quotas are activated, they affect all extent processing, which takes a
 performance hit. Activation of qgroups is not recommended unless the user
 intends to actually use them.
 
-STABILITY STATUS
-^^^^^^^^^^^^^^^^
-
-The qgroup implementation has turned out to be quite difficult as it affects
-the core of the filesystem operation. Qgroup users have hit various corner cases
-over time, such as incorrect accounting or system instability. The situation is
-gradually improving and issues found and fixed.
-
 .. _man-quota-hierarchical-quota-group-concepts:
 
 HIERARCHICAL QUOTA GROUP CONCEPTS

diff --git a/Documentation/btrfs-rescue.rst b/Documentation/btrfs-rescue.rst
@@ -9,7 +9,8 @@ SYNOPSIS
 DESCRIPTION
 -----------
 
-:command:`btrfs rescue` is used to try to recover a damaged btrfs filesystem.
+A set of commands that are targeting to fix a specific problem and may not
+suitable for :doc`btrfs-check`.
 
 SUBCOMMAND
 ----------
@@ -29,10 +30,10 @@ chunk-recover [options] <device>
 
 .. note::
    Since :command:`chunk-recover` will scan the whole device, it will be very
-   slow especially executed on a large device.
+   slow especially if executed on a large device.
 
 fix-device-size <device>
-        fix device size and super block total bytes values that do not match
+        Fix device size and super block total bytes values that do not match.
 
         Kernel 4.11 starts to check the device size more strictly and this might
         mismatch the stored value of total bytes. See the exact error message below.
@@ -51,7 +52,7 @@ fix-device-size <device>
                 WARNING: CPU: 3 PID: 439 at fs/btrfs/ctree.h:1559 btrfs_update_device+0x1c5/0x1d0 [btrfs]
 
 fix-data-checksum <device>
-	fix data checksum mismatch
+	Selectively fix data checksum mismatch.
 
 	There is a long existing problem that if a user space program is doing
 	direct IO and modifies the buffer before the write back finished, it
@@ -81,15 +82,15 @@ fix-data-checksum <device>
 .. _man-rescue-clear-ino-cache:
 
 clear-ino-cache <device>
-        Remove leftover items pertaining to the deprecated `inode cache` feature.
+        Remove leftover items pertaining to the deprecated *inode number cache* feature.
 
-	The `inode cache` feature (enabled by mount option "inode_cache") has been
-	completely removed in 5.11 kernel.
+        The feature enabled by mount option *inode_cache* has been completely
+        removed in 5.11 kernel.
 
 clear-space-cache <v1|v2> <device>
 	Completely remove the on-disk data of free space cache of given version.
 
-	Especially for v1 free space cache, `clear_cache` mount option would only
+	Especially for v1 free space cache, *clear_cache* mount option would only
 	remove the cache for updated block groups, the remaining would not be removed.
 	Thus this command is provided to manually clear the free space cache.
 
@@ -116,16 +117,12 @@ super-recover [options] <device>
                 (deprecated) alias for global *-v* option
 
 zero-log <device>
-        clear the filesystem log tree
+        Clear the filesystem log tree.
 
         This command will clear the filesystem log tree. This may fix a specific
-        set of problem when the filesystem mount fails due to the log replay. See below
+        set of problem when the filesystem mount fails during log replay. See below
         for sample stack traces that may show up in system log.
 
-        The common case where this happens was fixed a long time ago,
-        so it is unlikely that you will see this particular problem, but the command is
-        kept around.
-
         .. note::
                 Clearing the log may lead to loss of changes that were made
                 since the last transaction commit. This may be up to 30 seconds

diff --git a/Documentation/ch-quota-intro.rst b/Documentation/ch-quota-intro.rst
@@ -11,7 +11,7 @@ on the fly.
 
 On the other hand, the traditional approach has only a poor solution to
 restrict directories.
-At installation time, the harddisk can be partitioned so that every directory
+At installation time, the storage device can be partitioned so that every directory
 (e.g. :file:`/usr`, :file:`/var`, ...) that needs a limit gets its own partition.  The obvious
 problem is that those limits cannot be changed without a reinstallation.  The
 btrfs subvolume feature builds a bridge.  Subvolumes correspond in many ways to
@@ -37,7 +37,8 @@ space and the amount of exclusively referenced space.
 
 referenced
         space is the amount of data that can be reached from any of the
-        subvolumes contained in the qgroup, while
+        subvolumes contained in the qgroup
+
 exclusive
         is the amount of data where all references to this data can be reached
         from within this qgroup.
@@ -50,12 +51,12 @@ qgroup.  Qgroups are notated as *level/id*, e.g.  the qgroup 3/2 is a qgroup of
 level 3. For level 0, the leading *0/* can be omitted.
 Qgroups of level 0 get created automatically when a subvolume/snapshot gets
 created.  The ID of the qgroup corresponds to the ID of the subvolume, so 0/5
-is the qgroup for the root subvolume.
+is the qgroup for the toplevel subvolume.
 For the :command:`btrfs qgroup` command, the path to the subvolume can also be used
 instead of *0/ID*.  For all higher levels, the ID can be chosen freely.
 
 Each qgroup can contain a set of lower level qgroups, thus creating a hierarchy
-of qgroups. Figure 1 shows an example qgroup tree.
+of qgroups. Here's an example of qgroup tree:
 
 .. code-block:: none
 
@@ -75,8 +76,6 @@ of qgroups. Figure 1 shows an example qgroup tree.
                       |        /         \   /         \
         extents       1       2            3            4
 
-        Figure 1: Sample qgroup hierarchy
-
 At the bottom, some extents are depicted showing which qgroups reference which
 extents.  It is important to understand the notion of *referenced* vs
 *exclusive*.  In the example, qgroup 0/2 references extents 2 and 3, while 1/2