Merge tag 'for-6.13-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs updates from David Sterba:
 "Changes outside of btrfs: add io_uring command flag to track a dying
  task (the rest will go via the block git tree).

  User visible changes:

   - wire encoded read (ioctl) to io_uring commands, this can be used on
     itself, in the future this will allow 'send' to be asynchronous. As
     a consequence, the encoded read ioctl can also work in non-blocking
     mode

   - new ioctl to wait for cleaned subvolumes, no need to use the
     generic and root-only SEARCH_TREE ioctl, will be used by "btrfs
     subvol sync"

   - recognize different paths/symlinks for the same devices and don't
     report them during rescanning, this can be observed with LVM or DM

   - seeding device use case change, the sprout device (the one
     capturing new writes) will not clear the read-only status of the
     super block; this prevents accumulating space from deleted
     snapshots

  Performance improvements:

   - reduce lock contention when traversing extent buffers

   - reduce extent tree lock contention when searching for inline
     backref

   - switch from rb-trees to xarray for delayed ref tracking,
     improvements due to better cache locality, branching factors and
     more compact data structures

   - enable extent map shrinker again (prevent memory exhaustion under
     some types of IO load), reworked to run in a single worker thread
     (there used to be problems causing long stalls under memory
     pressure)

  Core changes:

   - raid-stripe-tree feature updates:
       - make device replace and scrub work
       - implement partial deletion of stripe extents
       - new selftests

   - split the config option BTRFS_DEBUG and add EXPERIMENTAL for
     features that are experimental or with known problems so we don't
     misuse debugging config for that

   - subpage mode updates (sector < page):
       - update compression implementations
       - update writepage, writeback

   - continued folio API conversions:
       - buffered writes

   - make buffered write copy one page at a time, preparatory work for
     future integration with large folios, may cause performance drop

   - proper locking of root item regarding starting send

   - error handling improvements

   - code cleanups and refactoring:
       - dead code removal
       - unused parameter reduction
       - lockdep assertions"

* tag 'for-6.13-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (119 commits)
  btrfs: send: check for read-only send root under critical section
  btrfs: send: check for dead send root under critical section
  btrfs: remove check for NULL fs_info at btrfs_folio_end_lock_bitmap()
  btrfs: fix warning on PTR_ERR() against NULL device at btrfs_control_ioctl()
  btrfs: fix a typo in btrfs_use_zone_append
  btrfs: avoid superfluous calls to free_extent_map() in btrfs_encoded_read()
  btrfs: simplify logic to decrement snapshot counter at btrfs_mksnapshot()
  btrfs: remove hole from struct btrfs_delayed_node
  btrfs: update stale comment for struct btrfs_delayed_ref_node::add_list
  btrfs: add new ioctl to wait for cleaned subvolumes
  btrfs: simplify range tracking in cow_file_range()
  btrfs: remove conditional path allocation in btrfs_read_locked_inode()
  btrfs: push cleanup into btrfs_read_locked_inode()
  io_uring/cmd: let cmds to know about dying task
  btrfs: add struct io_btrfs_cmd as type for io_uring_cmd_to_pdu()
  btrfs: add io_uring command for encoded reads (ENCODED_READ ioctl)
  btrfs: move priv off stack in btrfs_encoded_read_regular_fill_pages()
  btrfs: don't sleep in btrfs_encoded_read() if IOCB_NOWAIT is set
  btrfs: change btrfs_encoded_read() so that reading of extent is done by caller
  btrfs: remove pointless iocb::ki_pos addition in btrfs_encoded_read()
  ...

include/uapi/linux/btrfs.h

@@ -1049,6 +1049,29 @@ struct btrfs_ioctl_encoded_io_args {
 #define BTRFS_ENCODED_IO_ENCRYPTION_NONE 0
 #define BTRFS_ENCODED_IO_ENCRYPTION_TYPES 1
 
+/*
+ * Wait for subvolume cleaning process. This queries the kernel queue and it
+ * can change between the calls.
+ *
+ * - FOR_ONE	- specify the subvolid
+ * - FOR_QUEUED - wait for all currently queued
+ * - COUNT	- count number of queued
+ * - PEEK_FIRST - read which is the first in the queue (to be cleaned or being
+ * 		  cleaned already), or 0 if the queue is empty
+ * - PEEK_LAST  - read the last subvolid in the queue, or 0 if the queue is empty
+ */
+struct btrfs_ioctl_subvol_wait {
+	__u64 subvolid;
+	__u32 mode;
+	__u32 count;
+};
+
+#define BTRFS_SUBVOL_SYNC_WAIT_FOR_ONE		(0)
+#define BTRFS_SUBVOL_SYNC_WAIT_FOR_QUEUED	(1)
+#define BTRFS_SUBVOL_SYNC_COUNT			(2)
+#define BTRFS_SUBVOL_SYNC_PEEK_FIRST		(3)
+#define BTRFS_SUBVOL_SYNC_PEEK_LAST		(4)
+
 /* Error codes as returned by the kernel */
 enum btrfs_err_code {
 	BTRFS_ERROR_DEV_RAID1_MIN_NOT_MET = 1,
@@ -1181,6 +1204,8 @@ enum btrfs_err_code {
 				    struct btrfs_ioctl_encoded_io_args)
 #define BTRFS_IOC_ENCODED_WRITE _IOW(BTRFS_IOCTL_MAGIC, 64, \
 				     struct btrfs_ioctl_encoded_io_args)
+#define BTRFS_IOC_SUBVOL_SYNC_WAIT _IOW(BTRFS_IOCTL_MAGIC, 65, \
+					struct btrfs_ioctl_subvol_wait)
 
 #ifdef __cplusplus
 }