Merge tag 'for-4.20-part2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull more btrfs updates from David Sterba:
 "This contains a few minor updates and fixes that were under testing or
  arrived shortly after the merge window freeze, mostly stable material"

* tag 'for-4.20-part2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  Btrfs: fix use-after-free when dumping free space
  Btrfs: fix use-after-free during inode eviction
  btrfs: move the dio_sem higher up the callchain
  btrfs: don't run delayed_iputs in commit
  btrfs: fix insert_reserved error handling
  btrfs: only free reserved extent if we didn't insert it
  btrfs: don't use ctl->free_space for max_extent_size
  btrfs: set max_extent_size properly
  btrfs: reset max_extent_size properly
  MAINTAINERS: update my email address for btrfs
  btrfs: delayed-ref: extract find_first_ref_head from find_ref_head
  Btrfs: fix deadlock when writing out free space caches
  Btrfs: fix assertion on fsync of regular file when using no-holes feature
  Btrfs: fix null pointer dereference on compressed write path error

9 files changed, 111 insertions, 68 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 930241eb6e2d..5d1c3ae9f933 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3160,7 +3160,7 @@ F:	drivers/gpio/gpio-bt8xx.c
 
 BTRFS FILE SYSTEM
 M:	Chris Mason <clm@fb.com>
-M:	Josef Bacik <jbacik@fb.com>
+M:	Josef Bacik <josef@toxicpanda.com>
 M:	David Sterba <dsterba@suse.com>
 L:	linux-btrfs@vger.kernel.org
 W:	http://btrfs.wiki.kernel.org/
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 2ee43b6a4f09..539901fb5165 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1014,9 +1014,26 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 	if ((root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) && parent)
 		parent_start = parent->start;
 
+	/*
+	 * If we are COWing a node/leaf from the extent, chunk or device trees,
+	 * make sure that we do not finish block group creation of pending block
+	 * groups. We do this to avoid a deadlock.
+	 * COWing can result in allocation of a new chunk, and flushing pending
+	 * block groups (btrfs_create_pending_block_groups()) can be triggered
+	 * when finishing allocation of a new chunk. Creation of a pending block
+	 * group modifies the extent, chunk and device trees, therefore we could
+	 * deadlock with ourselves since we are holding a lock on an extent
+	 * buffer that btrfs_create_pending_block_groups() may try to COW later.
+	 */
+	if (root == fs_info->extent_root ||
+	    root == fs_info->chunk_root ||
+	    root == fs_info->dev_root)
+		trans->can_flush_pending_bgs = false;
+
 	cow = btrfs_alloc_tree_block(trans, root, parent_start,
 			root->root_key.objectid, &disk_key, level,
 			search_start, empty_size);
+	trans->can_flush_pending_bgs = true;
 	if (IS_ERR(cow))
 		return PTR_ERR(cow);
 
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index 5149165b49a4..9301b3ad9217 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -164,14 +164,27 @@ static struct btrfs_delayed_ref_node* tree_insert(struct rb_root_cached *root,
 	return NULL;
 }
 
+static struct btrfs_delayed_ref_head *find_first_ref_head(
+		struct btrfs_delayed_ref_root *dr)
+{
+	struct rb_node *n;
+	struct btrfs_delayed_ref_head *entry;
+
+	n = rb_first_cached(&dr->href_root);
+	if (!n)
+		return NULL;
+
+	entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node);
+
+	return entry;
+}
+
 /*
- * find an head entry based on bytenr. This returns the delayed ref
- * head if it was able to find one, or NULL if nothing was in that spot.
- * If return_bigger is given, the next bigger entry is returned if no exact
- * match is found. But if no bigger one is found then the first node of the
- * ref head tree will be returned.
+ * Find a head entry based on bytenr. This returns the delayed ref head if it
+ * was able to find one, or NULL if nothing was in that spot.  If return_bigger
+ * is given, the next bigger entry is returned if no exact match is found.
  */
-static struct btrfs_delayed_ref_head* find_ref_head(
+static struct btrfs_delayed_ref_head *find_ref_head(
 		struct btrfs_delayed_ref_root *dr, u64 bytenr,
 		bool return_bigger)
 {
@@ -195,10 +208,9 @@ static struct btrfs_delayed_ref_head* find_ref_head(
 		if (bytenr > entry->bytenr) {
 			n = rb_next(&entry->href_node);
 			if (!n)
-				n = rb_first_cached(&dr->href_root);
+				return NULL;
 			entry = rb_entry(n, struct btrfs_delayed_ref_head,
 					 href_node);
-			return entry;
 		}
 		return entry;
 	}
@@ -355,33 +367,25 @@ struct btrfs_delayed_ref_head *btrfs_select_ref_head(
 		struct btrfs_delayed_ref_root *delayed_refs)
 {
 	struct btrfs_delayed_ref_head *head;
-	u64 start;
-	bool loop = false;
 
 again:
-	start = delayed_refs->run_delayed_start;
-	head = find_ref_head(delayed_refs, start, true);
-	if (!head && !loop) {
+	head = find_ref_head(delayed_refs, delayed_refs->run_delayed_start,
+			     true);
+	if (!head && delayed_refs->run_delayed_start != 0) {
 		delayed_refs->run_delayed_start = 0;
-		start = 0;
-		loop = true;
-		head = find_ref_head(delayed_refs, start, true);
-		if (!head)
-			return NULL;
-	} else if (!head && loop) {
-		return NULL;
+		head = find_first_ref_head(delayed_refs);
 	}
+	if (!head)
+		return NULL;
 
 	while (head->processing) {
 		struct rb_node *node;
 
 		node = rb_next(&head->href_node);
 		if (!node) {
-			if (loop)
+			if (delayed_refs->run_delayed_start == 0)
 				return NULL;
 			delayed_refs->run_delayed_start = 0;
-			start = 0;
-			loop = true;
 			goto again;
 		}
 		head = rb_entry(node, struct btrfs_delayed_ref_head,
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index a4cd0221bc8d..a1febf155747 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2366,6 +2366,9 @@ static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
 					   insert_reserved);
 	else
 		BUG();
+	if (ret && insert_reserved)
+		btrfs_pin_extent(trans->fs_info, node->bytenr,
+				 node->num_bytes, 1);
 	return ret;
 }
 
@@ -2954,7 +2957,6 @@ int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
 	struct btrfs_delayed_ref_head *head;
 	int ret;
 	int run_all = count == (unsigned long)-1;
-	bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
 
 	/* We'll clean this up in btrfs_cleanup_transaction */
 	if (trans->aborted)
@@ -2971,7 +2973,6 @@ again:
 #ifdef SCRAMBLE_DELAYED_REFS
 	delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
 #endif
-	trans->can_flush_pending_bgs = false;
 	ret = __btrfs_run_delayed_refs(trans, count);
 	if (ret < 0) {
 		btrfs_abort_transaction(trans, ret);
@@ -3002,7 +3003,6 @@ again:
 		goto again;
 	}
 out:
-	trans->can_flush_pending_bgs = can_flush_pending_bgs;
 	return 0;
 }
 
@@ -4568,6 +4568,7 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
 			goto out;
 	} else {
 		ret = 1;
+		space_info->max_extent_size = 0;
 	}
 
 	space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
@@ -4589,11 +4590,9 @@ out:
 	 * the block groups that were made dirty during the lifetime of the
 	 * transaction.
 	 */
-	if (trans->can_flush_pending_bgs &&
-	    trans->chunk_bytes_reserved >= (u64)SZ_2M) {
+	if (trans->chunk_bytes_reserved >= (u64)SZ_2M)
 		btrfs_create_pending_block_groups(trans);
-		btrfs_trans_release_chunk_metadata(trans);
-	}
+
 	return ret;
 }
 
@@ -6464,6 +6463,7 @@ static void btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
 		space_info->bytes_readonly += num_bytes;
 	cache->reserved -= num_bytes;
 	space_info->bytes_reserved -= num_bytes;
+	space_info->max_extent_size = 0;
 
 	if (delalloc)
 		cache->delalloc_bytes -= num_bytes;
@@ -7260,6 +7260,7 @@ static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
 	struct btrfs_block_group_cache *block_group = NULL;
 	u64 search_start = 0;
 	u64 max_extent_size = 0;
+	u64 max_free_space = 0;
 	u64 empty_cluster = 0;
 	struct btrfs_space_info *space_info;
 	int loop = 0;
@@ -7555,8 +7556,8 @@ unclustered_alloc:
 			spin_lock(&ctl->tree_lock);
 			if (ctl->free_space <
 			    num_bytes + empty_cluster + empty_size) {
-				if (ctl->free_space > max_extent_size)
-					max_extent_size = ctl->free_space;
+				max_free_space = max(max_free_space,
+						     ctl->free_space);
 				spin_unlock(&ctl->tree_lock);
 				goto loop;
 			}
@@ -7723,6 +7724,8 @@ loop:
 	}
 out:
 	if (ret == -ENOSPC) {
+		if (!max_extent_size)
+			max_extent_size = max_free_space;
 		spin_lock(&space_info->lock);
 		space_info->max_extent_size = max_extent_size;
 		spin_unlock(&space_info->lock);
@@ -8004,21 +8007,14 @@ static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
 	}
 
 	path = btrfs_alloc_path();
-	if (!path) {
-		btrfs_free_and_pin_reserved_extent(fs_info,
-						   extent_key.objectid,
-						   fs_info->nodesize);
+	if (!path)
 		return -ENOMEM;
-	}
 
 	path->leave_spinning = 1;
 	ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
 				      &extent_key, size);
 	if (ret) {
 		btrfs_free_path(path);
-		btrfs_free_and_pin_reserved_extent(fs_info,
-						   extent_key.objectid,
-						   fs_info->nodesize);
 		return ret;
 	}
 
@@ -10132,9 +10128,10 @@ void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
 	struct btrfs_block_group_item item;
 	struct btrfs_key key;
 	int ret = 0;
-	bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
 
-	trans->can_flush_pending_bgs = false;
+	if (!trans->can_flush_pending_bgs)
+		return;
+
 	while (!list_empty(&trans->new_bgs)) {
 		block_group = list_first_entry(&trans->new_bgs,
 					       struct btrfs_block_group_cache,
@@ -10159,7 +10156,7 @@ void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
 next:
 		list_del_init(&block_group->bg_list);
 	}
-	trans->can_flush_pending_bgs = can_flush_pending_bgs;
+	btrfs_trans_release_chunk_metadata(trans);
 }
 
 int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used,
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 15b925142793..97c7a086f7bd 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -2078,6 +2078,14 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 		goto out;
 
 	inode_lock(inode);
+
+	/*
+	 * We take the dio_sem here because the tree log stuff can race with
+	 * lockless dio writes and get an extent map logged for an extent we
+	 * never waited on.  We need it this high up for lockdep reasons.
+	 */
+	down_write(&BTRFS_I(inode)->dio_sem);
+
 	atomic_inc(&root->log_batch);
 
 	/*
@@ -2086,6 +2094,7 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 	 */
 	ret = btrfs_wait_ordered_range(inode, start, len);
 	if (ret) {
+		up_write(&BTRFS_I(inode)->dio_sem);
 		inode_unlock(inode);
 		goto out;
 	}
@@ -2109,6 +2118,7 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 		 * checked called fsync.
 		 */
 		ret = filemap_check_wb_err(inode->i_mapping, file->f_wb_err);
+		up_write(&BTRFS_I(inode)->dio_sem);
 		inode_unlock(inode);
 		goto out;
 	}
@@ -2127,6 +2137,7 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 	trans = btrfs_start_transaction(root, 0);
 	if (IS_ERR(trans)) {
 		ret = PTR_ERR(trans);
+		up_write(&BTRFS_I(inode)->dio_sem);
 		inode_unlock(inode);
 		goto out;
 	}
@@ -2148,6 +2159,7 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 	 * file again, but that will end up using the synchronization
 	 * inside btrfs_sync_log to keep things safe.
 	 */
+	up_write(&BTRFS_I(inode)->dio_sem);
 	inode_unlock(inode);
 
 	/*
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 67441219d6c9..4ba0aedc878b 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -1772,6 +1772,13 @@ static int search_bitmap(struct btrfs_free_space_ctl *ctl,
 	return -1;
 }
 
+static inline u64 get_max_extent_size(struct btrfs_free_space *entry)
+{
+	if (entry->bitmap)
+		return entry->max_extent_size;
+	return entry->bytes;
+}
+
 /* Cache the size of the max extent in bytes */
 static struct btrfs_free_space *
 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
@@ -1793,8 +1800,8 @@ find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
 	for (node = &entry->offset_index; node; node = rb_next(node)) {
 		entry = rb_entry(node, struct btrfs_free_space, offset_index);
 		if (entry->bytes < *bytes) {
-			if (entry->bytes > *max_extent_size)
-				*max_extent_size = entry->bytes;
+			*max_extent_size = max(get_max_extent_size(entry),
+					       *max_extent_size);
 			continue;
 		}
 
@@ -1812,8 +1819,8 @@ find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
 		}
 
 		if (entry->bytes < *bytes + align_off) {
-			if (entry->bytes > *max_extent_size)
-				*max_extent_size = entry->bytes;
+			*max_extent_size = max(get_max_extent_size(entry),
+					       *max_extent_size);
 			continue;
 		}
 
@@ -1825,8 +1832,10 @@ find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
 				*offset = tmp;
 				*bytes = size;
 				return entry;
-			} else if (size > *max_extent_size) {
-				*max_extent_size = size;
+			} else {
+				*max_extent_size =
+					max(get_max_extent_size(entry),
+					    *max_extent_size);
 			}
 			continue;
 		}
@@ -2449,6 +2458,7 @@ void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
 	struct rb_node *n;
 	int count = 0;
 
+	spin_lock(&ctl->tree_lock);
 	for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
 		info = rb_entry(n, struct btrfs_free_space, offset_index);
 		if (info->bytes >= bytes && !block_group->ro)
@@ -2457,6 +2467,7 @@ void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
 			   info->offset, info->bytes,
 		       (info->bitmap) ? "yes" : "no");
 	}
+	spin_unlock(&ctl->tree_lock);
 	btrfs_info(fs_info, "block group has cluster?: %s",
 	       list_empty(&block_group->cluster_list) ? "no" : "yes");
 	btrfs_info(fs_info,
@@ -2685,8 +2696,8 @@ static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
 
 	err = search_bitmap(ctl, entry, &search_start, &search_bytes, true);
 	if (err) {
-		if (search_bytes > *max_extent_size)
-			*max_extent_size = search_bytes;
+		*max_extent_size = max(get_max_extent_size(entry),
+				       *max_extent_size);
 		return 0;
 	}
 
@@ -2723,8 +2734,9 @@ u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
 
 	entry = rb_entry(node, struct btrfs_free_space, offset_index);
 	while (1) {
-		if (entry->bytes < bytes && entry->bytes > *max_extent_size)
-			*max_extent_size = entry->bytes;
+		if (entry->bytes < bytes)
+			*max_extent_size = max(get_max_extent_size(entry),
+					       *max_extent_size);
 
 		if (entry->bytes < bytes ||
 		    (!entry->bitmap && entry->offset < min_start)) {
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 181c58b23110..d3df5b52278c 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -502,6 +502,7 @@ again:
 		pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
 		if (!pages) {
 			/* just bail out to the uncompressed code */
+			nr_pages = 0;
 			goto cont;
 		}
 
@@ -2940,6 +2941,7 @@ static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
 	bool truncated = false;
 	bool range_locked = false;
 	bool clear_new_delalloc_bytes = false;
+	bool clear_reserved_extent = true;
 
 	if (!test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
 	    !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags) &&
@@ -3043,10 +3045,12 @@ static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
 						logical_len, logical_len,
 						compress_type, 0, 0,
 						BTRFS_FILE_EXTENT_REG);
-		if (!ret)
+		if (!ret) {
+			clear_reserved_extent = false;
 			btrfs_release_delalloc_bytes(fs_info,
 						     ordered_extent->start,
 						     ordered_extent->disk_len);
+		}
 	}
 	unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
 			   ordered_extent->file_offset, ordered_extent->len,
@@ -3107,8 +3111,13 @@ out:
 		 * wrong we need to return the space for this ordered extent
 		 * back to the allocator.  We only free the extent in the
 		 * truncated case if we didn't write out the extent at all.
+		 *
+		 * If we made it past insert_reserved_file_extent before we
+		 * errored out then we don't need to do this as the accounting
+		 * has already been done.
 		 */
 		if ((ret || !logical_len) &&
+		    clear_reserved_extent &&
 		    !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
 		    !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
 			btrfs_free_reserved_extent(fs_info,
@@ -5259,11 +5268,13 @@ static void evict_inode_truncate_pages(struct inode *inode)
 		struct extent_state *cached_state = NULL;
 		u64 start;
 		u64 end;
+		unsigned state_flags;
 
 		node = rb_first(&io_tree->state);
 		state = rb_entry(node, struct extent_state, rb_node);
 		start = state->start;
 		end = state->end;
+		state_flags = state->state;
 		spin_unlock(&io_tree->lock);
 
 		lock_extent_bits(io_tree, start, end, &cached_state);
@@ -5276,7 +5287,7 @@ static void evict_inode_truncate_pages(struct inode *inode)
 		 *
 		 * Note, end is the bytenr of last byte, so we need + 1 here.
 		 */
-		if (state->state & EXTENT_DELALLOC)
+		if (state_flags & EXTENT_DELALLOC)
 			btrfs_qgroup_free_data(inode, NULL, start, end - start + 1);
 
 		clear_extent_bit(io_tree, start, end,
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 5686290a50e1..d1eeef9ec5da 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -2283,15 +2283,6 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
 
 	kmem_cache_free(btrfs_trans_handle_cachep, trans);
 
-	/*
-	 * If fs has been frozen, we can not handle delayed iputs, otherwise
-	 * it'll result in deadlock about SB_FREEZE_FS.
-	 */
-	if (current != fs_info->transaction_kthread &&
-	    current != fs_info->cleaner_kthread &&
-	    !test_bit(BTRFS_FS_FROZEN, &fs_info->flags))
-		btrfs_run_delayed_iputs(fs_info);
-
 	return ret;
 
 scrub_continue:
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 0dba09334a16..e07f3376b7df 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -4390,7 +4390,6 @@ static int btrfs_log_changed_extents(struct btrfs_trans_handle *trans,
 
 	INIT_LIST_HEAD(&extents);
 
-	down_write(&inode->dio_sem);
 	write_lock(&tree->lock);
 	test_gen = root->fs_info->last_trans_committed;
 	logged_start = start;
@@ -4456,7 +4455,6 @@ process:
 	}
 	WARN_ON(!list_empty(&extents));
 	write_unlock(&tree->lock);
-	up_write(&inode->dio_sem);
 
 	btrfs_release_path(path);
 	if (!ret)
@@ -4652,7 +4650,8 @@ static int btrfs_log_trailing_hole(struct btrfs_trans_handle *trans,
 			ASSERT(len == i_size ||
 			       (len == fs_info->sectorsize &&
 				btrfs_file_extent_compression(leaf, extent) !=
-				BTRFS_COMPRESS_NONE));
+				BTRFS_COMPRESS_NONE) ||
+			       (len < i_size && i_size < fs_info->sectorsize));
 			return 0;
 		}