Merge tag 'for-5.8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs updates from David Sterba:
 "Highlights:

   - speedup dead root detection during orphan cleanup, eg. when there
     are many deleted subvolumes waiting to be cleaned, the trees are
     now looked up in radix tree instead of a O(N^2) search

   - snapshot creation with inherited qgroup will mark the qgroup
     inconsistent, requires a rescan

   - send will emit file capabilities after chown, this produces a
     stream that does not need postprocessing to set the capabilities
     again

   - direct io ported to iomap infrastructure, cleaned up and simplified
     code, notably removing last use of struct buffer_head in btrfs code

  Core changes:

   - factor out backreference iteration, to be used by ordinary
     backreferences and relocation code

   - improved global block reserve utilization
      * better logic to serialize requests
      * increased maximum available for unlink
      * improved handling on large pages (64K)

   - direct io cleanups and fixes
      * simplify layering, where cloned bios were unnecessarily created
        for some cases
      * error handling fixes (submit, endio)
      * remove repair worker thread, used to avoid deadlocks during
        repair

   - refactored block group reading code, preparatory work for new type
     of block group storage that should improve mount time on large
     filesystems

  Cleanups:

   - cleaned up (and slightly sped up) set/get helpers for metadata data
     structure members

   - root bit REF_COWS got renamed to SHAREABLE to reflect the that the
     blocks of the tree get shared either among subvolumes or with the
     relocation trees

  Fixes:

   - when subvolume deletion fails due to ENOSPC, the filesystem is not
     turned read-only

   - device scan deals with devices from other filesystems that changed
     ownership due to overwrite (mkfs)

   - fix a race between scrub and block group removal/allocation

   - fix long standing bug of a runaway balance operation, printing the
     same line to the syslog, caused by a stale status bit on a reloc
     tree that prevented progress

   - fix corrupt log due to concurrent fsync of inodes with shared
     extents

   - fix space underflow for NODATACOW and buffered writes when it for
     some reason needs to fallback to COW mode"

* tag 'for-5.8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (133 commits)
  btrfs: fix space_info bytes_may_use underflow during space cache writeout
  btrfs: fix space_info bytes_may_use underflow after nocow buffered write
  btrfs: fix wrong file range cleanup after an error filling dealloc range
  btrfs: remove redundant local variable in read_block_for_search
  btrfs: open code key_search
  btrfs: split btrfs_direct_IO to read and write part
  btrfs: remove BTRFS_INODE_READDIO_NEED_LOCK
  fs: remove dio_end_io()
  btrfs: switch to iomap_dio_rw() for dio
  iomap: remove lockdep_assert_held()
  iomap: add a filesystem hook for direct I/O bio submission
  fs: export generic_file_buffered_read()
  btrfs: turn space cache writeout failure messages into debug messages
  btrfs: include error on messages about failure to write space/inode caches
  btrfs: remove useless 'fail_unlock' label from btrfs_csum_file_blocks()
  btrfs: do not ignore error from btrfs_next_leaf() when inserting checksums
  btrfs: make checksum item extension more efficient
  btrfs: fix corrupt log due to concurrent fsync of inodes with shared extents
  btrfs: unexport btrfs_compress_set_level()
  btrfs: simplify iget helpers
  ...

1 files changed, 73 insertions, 8 deletions

diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
index ff17a4420358..41ee88633769 100644
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -626,6 +626,7 @@ static int may_commit_transaction(struct btrfs_fs_info *fs_info,
 	struct reserve_ticket *ticket = NULL;
 	struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_block_rsv;
 	struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
+	struct btrfs_block_rsv *trans_rsv = &fs_info->trans_block_rsv;
 	struct btrfs_trans_handle *trans;
 	u64 bytes_needed;
 	u64 reclaim_bytes = 0;
@@ -688,6 +689,11 @@ static int may_commit_transaction(struct btrfs_fs_info *fs_info,
 	spin_lock(&delayed_refs_rsv->lock);
 	reclaim_bytes += delayed_refs_rsv->reserved;
 	spin_unlock(&delayed_refs_rsv->lock);
+
+	spin_lock(&trans_rsv->lock);
+	reclaim_bytes += trans_rsv->reserved;
+	spin_unlock(&trans_rsv->lock);
+
 	if (reclaim_bytes >= bytes_needed)
 		goto commit;
 	bytes_needed -= reclaim_bytes;
@@ -856,6 +862,34 @@ static inline int need_do_async_reclaim(struct btrfs_fs_info *fs_info,
 		!test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
 }
 
+static bool steal_from_global_rsv(struct btrfs_fs_info *fs_info,
+				  struct btrfs_space_info *space_info,
+				  struct reserve_ticket *ticket)
+{
+	struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
+	u64 min_bytes;
+
+	if (global_rsv->space_info != space_info)
+		return false;
+
+	spin_lock(&global_rsv->lock);
+	min_bytes = div_factor(global_rsv->size, 1);
+	if (global_rsv->reserved < min_bytes + ticket->bytes) {
+		spin_unlock(&global_rsv->lock);
+		return false;
+	}
+	global_rsv->reserved -= ticket->bytes;
+	ticket->bytes = 0;
+	list_del_init(&ticket->list);
+	wake_up(&ticket->wait);
+	space_info->tickets_id++;
+	if (global_rsv->reserved < global_rsv->size)
+		global_rsv->full = 0;
+	spin_unlock(&global_rsv->lock);
+
+	return true;
+}
+
 /*
  * maybe_fail_all_tickets - we've exhausted our flushing, start failing tickets
  * @fs_info - fs_info for this fs
@@ -888,6 +922,10 @@ static bool maybe_fail_all_tickets(struct btrfs_fs_info *fs_info,
 		ticket = list_first_entry(&space_info->tickets,
 					  struct reserve_ticket, list);
 
+		if (ticket->steal &&
+		    steal_from_global_rsv(fs_info, space_info, ticket))
+			return true;
+
 		/*
 		 * may_commit_transaction will avoid committing the transaction
 		 * if it doesn't feel like the space reclaimed by the commit
@@ -1104,6 +1142,7 @@ static int handle_reserve_ticket(struct btrfs_fs_info *fs_info,
 
 	switch (flush) {
 	case BTRFS_RESERVE_FLUSH_ALL:
+	case BTRFS_RESERVE_FLUSH_ALL_STEAL:
 		wait_reserve_ticket(fs_info, space_info, ticket);
 		break;
 	case BTRFS_RESERVE_FLUSH_LIMIT:
@@ -1125,11 +1164,17 @@ static int handle_reserve_ticket(struct btrfs_fs_info *fs_info,
 	ret = ticket->error;
 	if (ticket->bytes || ticket->error) {
 		/*
-		 * Need to delete here for priority tickets. For regular tickets
-		 * either the async reclaim job deletes the ticket from the list
-		 * or we delete it ourselves at wait_reserve_ticket().
+		 * We were a priority ticket, so we need to delete ourselves
+		 * from the list.  Because we could have other priority tickets
+		 * behind us that require less space, run
+		 * btrfs_try_granting_tickets() to see if their reservations can
+		 * now be made.
 		 */
-		remove_ticket(space_info, ticket);
+		if (!list_empty(&ticket->list)) {
+			remove_ticket(space_info, ticket);
+			btrfs_try_granting_tickets(fs_info, space_info);
+		}
+
 		if (!ret)
 			ret = -ENOSPC;
 	}
@@ -1145,6 +1190,16 @@ static int handle_reserve_ticket(struct btrfs_fs_info *fs_info,
 	return ret;
 }
 
+/*
+ * This returns true if this flush state will go through the ordinary flushing
+ * code.
+ */
+static inline bool is_normal_flushing(enum btrfs_reserve_flush_enum flush)
+{
+	return	(flush == BTRFS_RESERVE_FLUSH_ALL) ||
+		(flush == BTRFS_RESERVE_FLUSH_ALL_STEAL);
+}
+
 /**
  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
  * @root - the root we're allocating for
@@ -1175,8 +1230,17 @@ static int __reserve_metadata_bytes(struct btrfs_fs_info *fs_info,
 	spin_lock(&space_info->lock);
 	ret = -ENOSPC;
 	used = btrfs_space_info_used(space_info, true);
-	pending_tickets = !list_empty(&space_info->tickets) ||
-		!list_empty(&space_info->priority_tickets);
+
+	/*
+	 * We don't want NO_FLUSH allocations to jump everybody, they can
+	 * generally handle ENOSPC in a different way, so treat them the same as
+	 * normal flushers when it comes to skipping pending tickets.
+	 */
+	if (is_normal_flushing(flush) || (flush == BTRFS_RESERVE_NO_FLUSH))
+		pending_tickets = !list_empty(&space_info->tickets) ||
+			!list_empty(&space_info->priority_tickets);
+	else
+		pending_tickets = !list_empty(&space_info->priority_tickets);
 
 	/*
 	 * Carry on if we have enough space (short-circuit) OR call
@@ -1198,12 +1262,13 @@ static int __reserve_metadata_bytes(struct btrfs_fs_info *fs_info,
 	 * the list and we will do our own flushing further down.
 	 */
 	if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
-		ASSERT(space_info->reclaim_size >= 0);
 		ticket.bytes = orig_bytes;
 		ticket.error = 0;
 		space_info->reclaim_size += ticket.bytes;
 		init_waitqueue_head(&ticket.wait);
-		if (flush == BTRFS_RESERVE_FLUSH_ALL) {
+		ticket.steal = (flush == BTRFS_RESERVE_FLUSH_ALL_STEAL);
+		if (flush == BTRFS_RESERVE_FLUSH_ALL ||
+		    flush == BTRFS_RESERVE_FLUSH_ALL_STEAL) {
 			list_add_tail(&ticket.list, &space_info->tickets);
 			if (!space_info->flush) {
 				space_info->flush = 1;