Merge tag 'for-5.13-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs updates from David Sterba:
 "The updates this time are mostly stabilization, preparation and minor
  improvements.

  User visible improvements:

   - readahead for send, improving run time of full send by 10% and for
     incremental by 25%

   - make reflinks respect O_SYNC, O_DSYNC and S_SYNC flags

   - export supported sectorsize values in sysfs (currently only page
     size, more once full subpage support lands)

   - more graceful errors and warnings on 32bit systems when logical
     addresses for metadata reach the limit posed by unsigned long in
     page::index
      - error: fail mount if there's a metadata block beyond the limit
      - error: new metadata block would be at unreachable address
      - warn when 5/8th of the limit is reached, for 4K page systems
        it's 10T, for 64K page it's 160T

   - zoned mode
      - relocated zones get reset at the end instead of discard
      - automatic background reclaim of zones that have 75%+ of unusable
        space, the threshold is tunable in sysfs

  Fixes:

   - fsync and tree mod log fixes

   - fix inefficient preemptive reclaim calculations

   - fix exhaustion of the system chunk array due to concurrent
     allocations

   - fix fallback to no compression when racing with remount

   - preemptive fix for dm-crypt on zoned device that does not properly
     advertise zoned support

  Core changes:

   - add inode lock to synchronize mmap and other block updates (eg.
     deduplication, fallocate, fsync)

   - kmap conversions to new kmap_local API

   - subpage support (continued)
      - new helpers for page state/extent buffer tracking
      - metadata changes now support read and write

   - error handling through out relocation call paths

   - many other cleanups and code simplifications"

* tag 'for-5.13-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (112 commits)
  btrfs: zoned: automatically reclaim zones
  btrfs: rename delete_unused_bgs_mutex to reclaim_bgs_lock
  btrfs: zoned: reset zones of relocated block groups
  btrfs: more graceful errors/warnings on 32bit systems when reaching limits
  btrfs: zoned: fix unpaired block group unfreeze during device replace
  btrfs: fix race when picking most recent mod log operation for an old root
  btrfs: fix metadata extent leak after failure to create subvolume
  btrfs: handle remount to no compress during compression
  btrfs: zoned: fail mount if the device does not support zone append
  btrfs: fix race between transaction aborts and fsyncs leading to use-after-free
  btrfs: introduce submit_eb_subpage() to submit a subpage metadata page
  btrfs: make lock_extent_buffer_for_io() to be subpage compatible
  btrfs: introduce write_one_subpage_eb() function
  btrfs: introduce end_bio_subpage_eb_writepage() function
  btrfs: check return value of btrfs_commit_transaction in relocation
  btrfs: do proper error handling in merge_reloc_roots
  btrfs: handle extent corruption with select_one_root properly
  btrfs: cleanup error handling in prepare_to_merge
  btrfs: do not panic in __add_reloc_root
  btrfs: handle __add_reloc_root failures in btrfs_recover_relocation
  ...

46 files changed, 2964 insertions, 1582 deletions

diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index b4fb997eda16..cec88a66bd6c 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -30,7 +30,7 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
 	   reada.o backref.o ulist.o qgroup.o send.o dev-replace.o raid56.o \
 	   uuid-tree.o props.o free-space-tree.o tree-checker.o space-info.o \
 	   block-rsv.o delalloc-space.o block-group.o discard.o reflink.o \
-	   subpage.o
+	   subpage.o tree-mod-log.o
 
 btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o
 btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index f47c1528eb9a..117d423fdb93 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -14,6 +14,7 @@
 #include "delayed-ref.h"
 #include "locking.h"
 #include "misc.h"
+#include "tree-mod-log.h"
 
 /* Just an arbitrary number so we can be sure this happened */
 #define BACKREF_FOUND_SHARED 6
@@ -452,7 +453,7 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
 	if (path->slots[0] >= btrfs_header_nritems(eb) ||
 	    is_shared_data_backref(preftrees, eb->start) ||
 	    ref->root_id != btrfs_header_owner(eb)) {
-		if (time_seq == SEQ_LAST)
+		if (time_seq == BTRFS_SEQ_LAST)
 			ret = btrfs_next_leaf(root, path);
 		else
 			ret = btrfs_next_old_leaf(root, path, time_seq);
@@ -476,7 +477,7 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
 		if (slot == 0 &&
 		    (is_shared_data_backref(preftrees, eb->start) ||
 		     ref->root_id != btrfs_header_owner(eb))) {
-			if (time_seq == SEQ_LAST)
+			if (time_seq == BTRFS_SEQ_LAST)
 				ret = btrfs_next_leaf(root, path);
 			else
 				ret = btrfs_next_old_leaf(root, path, time_seq);
@@ -514,7 +515,7 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
 			eie = NULL;
 		}
 next:
-		if (time_seq == SEQ_LAST)
+		if (time_seq == BTRFS_SEQ_LAST)
 			ret = btrfs_next_item(root, path);
 		else
 			ret = btrfs_next_old_item(root, path, time_seq);
@@ -574,7 +575,7 @@ static int resolve_indirect_ref(struct btrfs_fs_info *fs_info,
 
 	if (path->search_commit_root)
 		root_level = btrfs_header_level(root->commit_root);
-	else if (time_seq == SEQ_LAST)
+	else if (time_seq == BTRFS_SEQ_LAST)
 		root_level = btrfs_header_level(root->node);
 	else
 		root_level = btrfs_old_root_level(root, time_seq);
@@ -605,7 +606,7 @@ static int resolve_indirect_ref(struct btrfs_fs_info *fs_info,
 	    search_key.offset >= LLONG_MAX)
 		search_key.offset = 0;
 	path->lowest_level = level;
-	if (time_seq == SEQ_LAST)
+	if (time_seq == BTRFS_SEQ_LAST)
 		ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
 	else
 		ret = btrfs_search_old_slot(root, &search_key, path, time_seq);
@@ -1147,8 +1148,8 @@ static int add_keyed_refs(struct btrfs_fs_info *fs_info,
  * indirect refs to their parent bytenr.
  * When roots are found, they're added to the roots list
  *
- * If time_seq is set to SEQ_LAST, it will not search delayed_refs, and behave
- * much like trans == NULL case, the difference only lies in it will not
+ * If time_seq is set to BTRFS_SEQ_LAST, it will not search delayed_refs, and
+ * behave much like trans == NULL case, the difference only lies in it will not
  * commit root.
  * The special case is for qgroup to search roots in commit_transaction().
  *
@@ -1199,7 +1200,7 @@ static int find_parent_nodes(struct btrfs_trans_handle *trans,
 		path->skip_locking = 1;
 	}
 
-	if (time_seq == SEQ_LAST)
+	if (time_seq == BTRFS_SEQ_LAST)
 		path->skip_locking = 1;
 
 	/*
@@ -1217,9 +1218,9 @@ again:
 
 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 	if (trans && likely(trans->type != __TRANS_DUMMY) &&
-	    time_seq != SEQ_LAST) {
+	    time_seq != BTRFS_SEQ_LAST) {
 #else
-	if (trans && time_seq != SEQ_LAST) {
+	if (trans && time_seq != BTRFS_SEQ_LAST) {
 #endif
 		/*
 		 * look if there are updates for this ref queued and lock the
@@ -1527,7 +1528,7 @@ int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr,
 	struct btrfs_trans_handle *trans;
 	struct ulist_iterator uiter;
 	struct ulist_node *node;
-	struct seq_list elem = SEQ_LIST_INIT(elem);
+	struct btrfs_seq_list elem = BTRFS_SEQ_LIST_INIT(elem);
 	int ret = 0;
 	struct share_check shared = {
 		.root_objectid = root->root_key.objectid,
@@ -1953,7 +1954,7 @@ int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
 	struct ulist *roots = NULL;
 	struct ulist_node *ref_node = NULL;
 	struct ulist_node *root_node = NULL;
-	struct seq_list tree_mod_seq_elem = SEQ_LIST_INIT(tree_mod_seq_elem);
+	struct btrfs_seq_list seq_elem = BTRFS_SEQ_LIST_INIT(seq_elem);
 	struct ulist_iterator ref_uiter;
 	struct ulist_iterator root_uiter;
 
@@ -1971,12 +1972,12 @@ int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
 	}
 
 	if (trans)
-		btrfs_get_tree_mod_seq(fs_info, &tree_mod_seq_elem);
+		btrfs_get_tree_mod_seq(fs_info, &seq_elem);
 	else
 		down_read(&fs_info->commit_root_sem);
 
 	ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid,
-				   tree_mod_seq_elem.seq, &refs,
+				   seq_elem.seq, &refs,
 				   &extent_item_pos, ignore_offset);
 	if (ret)
 		goto out;
@@ -1984,7 +1985,7 @@ int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
 	ULIST_ITER_INIT(&ref_uiter);
 	while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) {
 		ret = btrfs_find_all_roots_safe(trans, fs_info, ref_node->val,
-						tree_mod_seq_elem.seq, &roots,
+						seq_elem.seq, &roots,
 						ignore_offset);
 		if (ret)
 			break;
@@ -2007,7 +2008,7 @@ int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
 	free_leaf_list(refs);
 out:
 	if (trans) {
-		btrfs_put_tree_mod_seq(fs_info, &tree_mod_seq_elem);
+		btrfs_put_tree_mod_seq(fs_info, &seq_elem);
 		btrfs_end_transaction(trans);
 	} else {
 		up_read(&fs_info->commit_root_sem);
diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 744b99ddc28c..aa57bdc8fc89 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -1289,7 +1289,7 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
 	 * Long running balances can keep us blocked here for eternity, so
 	 * simply skip deletion if we're unable to get the mutex.
 	 */
-	if (!mutex_trylock(&fs_info->delete_unused_bgs_mutex))
+	if (!mutex_trylock(&fs_info->reclaim_bgs_lock))
 		return;
 
 	spin_lock(&fs_info->unused_bgs_lock);
@@ -1462,12 +1462,12 @@ next:
 		spin_lock(&fs_info->unused_bgs_lock);
 	}
 	spin_unlock(&fs_info->unused_bgs_lock);
-	mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+	mutex_unlock(&fs_info->reclaim_bgs_lock);
 	return;
 
 flip_async:
 	btrfs_end_transaction(trans);
-	mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+	mutex_unlock(&fs_info->reclaim_bgs_lock);
 	btrfs_put_block_group(block_group);
 	btrfs_discard_punt_unused_bgs_list(fs_info);
 }
@@ -1485,6 +1485,97 @@ void btrfs_mark_bg_unused(struct btrfs_block_group *bg)
 	spin_unlock(&fs_info->unused_bgs_lock);
 }
 
+void btrfs_reclaim_bgs_work(struct work_struct *work)
+{
+	struct btrfs_fs_info *fs_info =
+		container_of(work, struct btrfs_fs_info, reclaim_bgs_work);
+	struct btrfs_block_group *bg;
+	struct btrfs_space_info *space_info;
+	int ret;
+
+	if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
+		return;
+
+	if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE))
+		return;
+
+	mutex_lock(&fs_info->reclaim_bgs_lock);
+	spin_lock(&fs_info->unused_bgs_lock);
+	while (!list_empty(&fs_info->reclaim_bgs)) {
+		bg = list_first_entry(&fs_info->reclaim_bgs,
+				      struct btrfs_block_group,
+				      bg_list);
+		list_del_init(&bg->bg_list);
+
+		space_info = bg->space_info;
+		spin_unlock(&fs_info->unused_bgs_lock);
+
+		/* Don't race with allocators so take the groups_sem */
+		down_write(&space_info->groups_sem);
+
+		spin_lock(&bg->lock);
+		if (bg->reserved || bg->pinned || bg->ro) {
+			/*
+			 * We want to bail if we made new allocations or have
+			 * outstanding allocations in this block group.  We do
+			 * the ro check in case balance is currently acting on
+			 * this block group.
+			 */
+			spin_unlock(&bg->lock);
+			up_write(&space_info->groups_sem);
+			goto next;
+		}
+		spin_unlock(&bg->lock);
+
+		/* Get out fast, in case we're unmounting the filesystem */
+		if (btrfs_fs_closing(fs_info)) {
+			up_write(&space_info->groups_sem);
+			goto next;
+		}
+
+		ret = inc_block_group_ro(bg, 0);
+		up_write(&space_info->groups_sem);
+		if (ret < 0)
+			goto next;
+
+		btrfs_info(fs_info, "reclaiming chunk %llu with %llu%% used",
+				bg->start, div_u64(bg->used * 100, bg->length));
+		trace_btrfs_reclaim_block_group(bg);
+		ret = btrfs_relocate_chunk(fs_info, bg->start);
+		if (ret)
+			btrfs_err(fs_info, "error relocating chunk %llu",
+				  bg->start);
+
+next:
+		btrfs_put_block_group(bg);
+		spin_lock(&fs_info->unused_bgs_lock);
+	}
+	spin_unlock(&fs_info->unused_bgs_lock);
+	mutex_unlock(&fs_info->reclaim_bgs_lock);
+	btrfs_exclop_finish(fs_info);
+}
+
+void btrfs_reclaim_bgs(struct btrfs_fs_info *fs_info)
+{
+	spin_lock(&fs_info->unused_bgs_lock);
+	if (!list_empty(&fs_info->reclaim_bgs))
+		queue_work(system_unbound_wq, &fs_info->reclaim_bgs_work);
+	spin_unlock(&fs_info->unused_bgs_lock);
+}
+
+void btrfs_mark_bg_to_reclaim(struct btrfs_block_group *bg)
+{
+	struct btrfs_fs_info *fs_info = bg->fs_info;
+
+	spin_lock(&fs_info->unused_bgs_lock);
+	if (list_empty(&bg->bg_list)) {
+		btrfs_get_block_group(bg);
+		trace_btrfs_add_reclaim_block_group(bg);
+		list_add_tail(&bg->bg_list, &fs_info->reclaim_bgs);
+	}
+	spin_unlock(&fs_info->unused_bgs_lock);
+}
+
 static int read_bg_from_eb(struct btrfs_fs_info *fs_info, struct btrfs_key *key,
 			   struct btrfs_path *path)
 {
@@ -2267,29 +2358,33 @@ int btrfs_inc_block_group_ro(struct btrfs_block_group *cache,
 	struct btrfs_trans_handle *trans;
 	u64 alloc_flags;
 	int ret;
+	bool dirty_bg_running;
 
-again:
-	trans = btrfs_join_transaction(fs_info->extent_root);
-	if (IS_ERR(trans))
-		return PTR_ERR(trans);
+	do {
+		trans = btrfs_join_transaction(fs_info->extent_root);
+		if (IS_ERR(trans))
+			return PTR_ERR(trans);
 
-	/*
-	 * we're not allowed to set block groups readonly after the dirty
-	 * block groups cache has started writing.  If it already started,
-	 * back off and let this transaction commit
-	 */
-	mutex_lock(&fs_info->ro_block_group_mutex);
-	if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
-		u64 transid = trans->transid;
+		dirty_bg_running = false;
 
-		mutex_unlock(&fs_info->ro_block_group_mutex);
-		btrfs_end_transaction(trans);
+		/*
+		 * We're not allowed to set block groups readonly after the dirty
+		 * block group cache has started writing.  If it already started,
+		 * back off and let this transaction commit.
+		 */
+		mutex_lock(&fs_info->ro_block_group_mutex);
+		if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
+			u64 transid = trans->transid;
 
-		ret = btrfs_wait_for_commit(fs_info, transid);
-		if (ret)
-			return ret;
-		goto again;
-	}
+			mutex_unlock(&fs_info->ro_block_group_mutex);
+			btrfs_end_transaction(trans);
+
+			ret = btrfs_wait_for_commit(fs_info, transid);
+			if (ret)
+				return ret;
+			dirty_bg_running = true;
+		}
+	} while (dirty_bg_running);
 
 	if (do_chunk_alloc) {
 		/*
@@ -3269,6 +3364,7 @@ static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
  */
 void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
 {
+	struct btrfs_transaction *cur_trans = trans->transaction;
 	struct btrfs_fs_info *fs_info = trans->fs_info;
 	struct btrfs_space_info *info;
 	u64 left;
@@ -3283,6 +3379,7 @@ void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
 	lockdep_assert_held(&fs_info->chunk_mutex);
 
 	info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
+again:
 	spin_lock(&info->lock);
 	left = info->total_bytes - btrfs_space_info_used(info, true);
 	spin_unlock(&info->lock);
@@ -3301,6 +3398,58 @@ void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
 
 	if (left < thresh) {
 		u64 flags = btrfs_system_alloc_profile(fs_info);
+		u64 reserved = atomic64_read(&cur_trans->chunk_bytes_reserved);
+
+		/*
+		 * If there's not available space for the chunk tree (system
+		 * space) and there are other tasks that reserved space for
+		 * creating a new system block group, wait for them to complete
+		 * the creation of their system block group and release excess
+		 * reserved space. We do this because:
+		 *
+		 * *) We can end up allocating more system chunks than necessary
+		 *    when there are multiple tasks that are concurrently
+		 *    allocating block groups, which can lead to exhaustion of
+		 *    the system array in the superblock;
+		 *
+		 * *) If we allocate extra and unnecessary system block groups,
+		 *    despite being empty for a long time, and possibly forever,
+		 *    they end not being added to the list of unused block groups
+		 *    because that typically happens only when deallocating the
+		 *    last extent from a block group - which never happens since
+		 *    we never allocate from them in the first place. The few
+		 *    exceptions are when mounting a filesystem or running scrub,
+		 *    which add unused block groups to the list of unused block
+		 *    groups, to be deleted by the cleaner kthread.
+		 *    And even when they are added to the list of unused block
+		 *    groups, it can take a long time until they get deleted,
+		 *    since the cleaner kthread might be sleeping or busy with
+		 *    other work (deleting subvolumes, running delayed iputs,
+		 *    defrag scheduling, etc);
+		 *
+		 * This is rare in practice, but can happen when too many tasks
+		 * are allocating blocks groups in parallel (via fallocate())
+		 * and before the one that reserved space for a new system block
+		 * group finishes the block group creation and releases the space
+		 * reserved in excess (at btrfs_create_pending_block_groups()),
+		 * other tasks end up here and see free system space temporarily
+		 * not enough for updating the chunk tree.
+		 *
+		 * We unlock the chunk mutex before waiting for such tasks and
+		 * lock it again after the wait, otherwise we would deadlock.
+		 * It is safe to do so because allocating a system chunk is the
+		 * first thing done while allocating a new block group.
+		 */
+		if (reserved > trans->chunk_bytes_reserved) {
+			const u64 min_needed = reserved - thresh;
+
+			mutex_unlock(&fs_info->chunk_mutex);
+			wait_event(cur_trans->chunk_reserve_wait,
+			   atomic64_read(&cur_trans->chunk_bytes_reserved) <=
+			   min_needed);
+			mutex_lock(&fs_info->chunk_mutex);
+			goto again;
+		}
 
 		/*
 		 * Ignore failure to create system chunk. We might end up not
@@ -3315,8 +3464,10 @@ void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
 		ret = btrfs_block_rsv_add(fs_info->chunk_root,
 					  &fs_info->chunk_block_rsv,
 					  thresh, BTRFS_RESERVE_NO_FLUSH);
-		if (!ret)
+		if (!ret) {
+			atomic64_add(thresh, &cur_trans->chunk_bytes_reserved);
 			trans->chunk_bytes_reserved += thresh;
+		}
 	}
 }
 
@@ -3386,6 +3537,16 @@ int btrfs_free_block_groups(struct btrfs_fs_info *info)
 	}
 	spin_unlock(&info->unused_bgs_lock);
 
+	spin_lock(&info->unused_bgs_lock);
+	while (!list_empty(&info->reclaim_bgs)) {
+		block_group = list_first_entry(&info->reclaim_bgs,
+					       struct btrfs_block_group,
+					       bg_list);
+		list_del_init(&block_group->bg_list);
+		btrfs_put_block_group(block_group);
+	}
+	spin_unlock(&info->unused_bgs_lock);
+
 	spin_lock(&info->block_group_cache_lock);
 	while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
 		block_group = rb_entry(n, struct btrfs_block_group,
diff --git a/fs/btrfs/block-group.h b/fs/btrfs/block-group.h
index 3ecc3372a5ce..7b927425dc71 100644
--- a/fs/btrfs/block-group.h
+++ b/fs/btrfs/block-group.h
@@ -264,6 +264,9 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 			     u64 group_start, struct extent_map *em);
 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info);
 void btrfs_mark_bg_unused(struct btrfs_block_group *bg);
+void btrfs_reclaim_bgs_work(struct work_struct *work);
+void btrfs_reclaim_bgs(struct btrfs_fs_info *fs_info);
+void btrfs_mark_bg_to_reclaim(struct btrfs_block_group *bg);
 int btrfs_read_block_groups(struct btrfs_fs_info *info);
 int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used,
 			   u64 type, u64 chunk_offset, u64 size);
diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index 28e202e89660..c652e19ad74e 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -220,6 +220,7 @@ struct btrfs_inode {
 	/* Hook into fs_info->delayed_iputs */
 	struct list_head delayed_iput;
 
+	struct rw_semaphore i_mmap_lock;
 	struct inode vfs_inode;
 };
 
@@ -299,24 +300,30 @@ static inline void btrfs_mod_outstanding_extents(struct btrfs_inode *inode,
 						  mod);
 }
 
-static inline int btrfs_inode_in_log(struct btrfs_inode *inode, u64 generation)
+/*
+ * Called every time after doing a buffered, direct IO or memory mapped write.
+ *
+ * This is to ensure that if we write to a file that was previously fsynced in
+ * the current transaction, then try to fsync it again in the same transaction,
+ * we will know that there were changes in the file and that it needs to be
+ * logged.
+ */
+static inline void btrfs_set_inode_last_sub_trans(struct btrfs_inode *inode)
+{
+	spin_lock(&inode->lock);
+	inode->last_sub_trans = inode->root->log_transid;
+	spin_unlock(&inode->lock);
+}
+
+static inline bool btrfs_inode_in_log(struct btrfs_inode *inode, u64 generation)
 {
-	int ret = 0;
+	bool ret = false;
 
 	spin_lock(&inode->lock);
 	if (inode->logged_trans == generation &&
 	    inode->last_sub_trans <= inode->last_log_commit &&
-	    inode->last_sub_trans <= inode->root->last_log_commit) {
-		/*
-		 * After a ranged fsync we might have left some extent maps
-		 * (that fall outside the fsync's range). So return false
-		 * here if the list isn't empty, to make sure btrfs_log_inode()
-		 * will be called and process those extent maps.
-		 */
-		smp_mb();
-		if (list_empty(&inode->extent_tree.modified_extents))
-			ret = 1;
-	}
+	    inode->last_sub_trans <= inode->root->last_log_commit)
+		ret = true;
 	spin_unlock(&inode->lock);
 	return ret;
 }
diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
index 113cb85c1fd4..169508609324 100644
--- a/fs/btrfs/check-integrity.c
+++ b/fs/btrfs/check-integrity.c
@@ -1555,10 +1555,11 @@ static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
 		BUG_ON(!block_ctx->pagev);
 		num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
 			    PAGE_SHIFT;
+		/* Pages must be unmapped in reverse order */
 		while (num_pages > 0) {
 			num_pages--;
 			if (block_ctx->datav[num_pages]) {
-				kunmap(block_ctx->pagev[num_pages]);
+				kunmap_local(block_ctx->datav[num_pages]);
 				block_ctx->datav[num_pages] = NULL;
 			}
 			if (block_ctx->pagev[num_pages]) {
@@ -1637,7 +1638,7 @@ static int btrfsic_read_block(struct btrfsic_state *state,
 		i = j;
 	}
 	for (i = 0; i < num_pages; i++)
-		block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
+		block_ctx->datav[i] = kmap_local_page(block_ctx->pagev[i]);
 
 	return block_ctx->len;
 }
@@ -2677,7 +2678,7 @@ static void __btrfsic_submit_bio(struct bio *bio)
 	dev_state = btrfsic_dev_state_lookup(bio->bi_bdev->bd_dev);
 	if (NULL != dev_state &&
 	    (bio_op(bio) == REQ_OP_WRITE) && bio_has_data(bio)) {
-		unsigned int i = 0;
+		int i = 0;
 		u64 dev_bytenr;
 		u64 cur_bytenr;
 		struct bio_vec bvec;
@@ -2702,7 +2703,7 @@ static void __btrfsic_submit_bio(struct bio *bio)
 
 		bio_for_each_segment(bvec, bio, iter) {
 			BUG_ON(bvec.bv_len != PAGE_SIZE);
-			mapped_datav[i] = kmap(bvec.bv_page);
+			mapped_datav[i] = kmap_local_page(bvec.bv_page);
 			i++;
 
 			if (dev_state->state->print_mask &
@@ -2715,8 +2716,9 @@ static void __btrfsic_submit_bio(struct bio *bio)
 					      mapped_datav, segs,
 					      bio, &bio_is_patched,
 					      bio->bi_opf);
-		bio_for_each_segment(bvec, bio, iter)
-			kunmap(bvec.bv_page);
+		/* Unmap in reverse order */
+		for (--i; i >= 0; i--)
+			kunmap_local(mapped_datav[i]);
 		kfree(mapped_datav);
 	} else if (NULL != dev_state && (bio->bi_opf & REQ_PREFLUSH)) {
 		if (dev_state->state->print_mask &
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 3f4c832abfed..17f93fd28f7e 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -80,10 +80,15 @@ static int compression_compress_pages(int type, struct list_head *ws,
 	case BTRFS_COMPRESS_NONE:
 	default:
 		/*
-		 * This can't happen, the type is validated several times
-		 * before we get here. As a sane fallback, return what the
-		 * callers will understand as 'no compression happened'.
+		 * This can happen when compression races with remount setting
+		 * it to 'no compress', while caller doesn't call
+		 * inode_need_compress() to check if we really need to
+		 * compress.
+		 *
+		 * Not a big deal, just need to inform caller that we
+		 * haven't allocated any pages yet.
 		 */
+		*out_pages = 0;
 		return -E2BIG;
 	}
 }
@@ -1611