Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs

Pull btrfs update from Chris Mason:
 "From a feature point of view, most of the code here comes from Miao
  Xie and others at Fujitsu to implement scrubbing and replacing devices
  on raid56.  This has been in development for a while, and it's a big
  improvement.

  Filipe and Josef have a great assortment of fixes, many of which solve
  problems corruptions either after a crash or in error conditions.  I
  still have a round two from Filipe for next week that solves
  corruptions with discard and block group removal"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (62 commits)
  Btrfs: make get_caching_control unconditionally return the ctl
  Btrfs: fix unprotected deletion from pending_chunks list
  Btrfs: fix fs mapping extent map leak
  Btrfs: fix memory leak after block remove + trimming
  Btrfs: make btrfs_abort_transaction consider existence of new block groups
  Btrfs: fix race between writing free space cache and trimming
  Btrfs: fix race between fs trimming and block group remove/allocation
  Btrfs, replace: enable dev-replace for raid56
  Btrfs: fix freeing used extents after removing empty block group
  Btrfs: fix crash caused by block group removal
  Btrfs: fix invalid block group rbtree access after bg is removed
  Btrfs, raid56: fix use-after-free problem in the final device replace procedure on raid56
  Btrfs, replace: write raid56 parity into the replace target device
  Btrfs, replace: write dirty pages into the replace target device
  Btrfs, raid56: support parity scrub on raid56
  Btrfs, raid56: use a variant to record the operation type
  Btrfs, scrub: repair the common data on RAID5/6 if it is corrupted
  Btrfs, raid56: don't change bbio and raid_map
  Btrfs: remove unnecessary code of stripe_index assignment in __btrfs_map_block
  Btrfs: remove noused bbio_ret in __btrfs_map_block in condition
  ...

1 files changed, 159 insertions, 52 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 47c1ba141082..222d6aea4a8a 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -315,12 +315,6 @@ get_caching_control(struct btrfs_block_group_cache *cache)
 	struct btrfs_caching_control *ctl;
 
 	spin_lock(&cache->lock);
-	if (cache->cached != BTRFS_CACHE_STARTED) {
-		spin_unlock(&cache->lock);
-		return NULL;
-	}
-
-	/* We're loading it the fast way, so we don't have a caching_ctl. */
 	if (!cache->caching_ctl) {
 		spin_unlock(&cache->lock);
 		return NULL;
@@ -594,6 +588,7 @@ static int cache_block_group(struct btrfs_block_group_cache *cache,
 	spin_unlock(&cache->lock);
 
 	if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
+		mutex_lock(&caching_ctl->mutex);
 		ret = load_free_space_cache(fs_info, cache);
 
 		spin_lock(&cache->lock);
@@ -601,15 +596,19 @@ static int cache_block_group(struct btrfs_block_group_cache *cache,
 			cache->caching_ctl = NULL;
 			cache->cached = BTRFS_CACHE_FINISHED;
 			cache->last_byte_to_unpin = (u64)-1;
+			caching_ctl->progress = (u64)-1;
 		} else {
 			if (load_cache_only) {
 				cache->caching_ctl = NULL;
 				cache->cached = BTRFS_CACHE_NO;
 			} else {
 				cache->cached = BTRFS_CACHE_STARTED;
+				cache->has_caching_ctl = 1;
 			}
 		}
 		spin_unlock(&cache->lock);
+		mutex_unlock(&caching_ctl->mutex);
+
 		wake_up(&caching_ctl->wait);
 		if (ret == 1) {
 			put_caching_control(caching_ctl);
@@ -627,6 +626,7 @@ static int cache_block_group(struct btrfs_block_group_cache *cache,
 			cache->cached = BTRFS_CACHE_NO;
 		} else {
 			cache->cached = BTRFS_CACHE_STARTED;
+			cache->has_caching_ctl = 1;
 		}
 		spin_unlock(&cache->lock);
 		wake_up(&caching_ctl->wait);
@@ -3162,7 +3162,19 @@ next_block_group(struct btrfs_root *root,
 		 struct btrfs_block_group_cache *cache)
 {
 	struct rb_node *node;
+
 	spin_lock(&root->fs_info->block_group_cache_lock);
+
+	/* If our block group was removed, we need a full search. */
+	if (RB_EMPTY_NODE(&cache->cache_node)) {
+		const u64 next_bytenr = cache->key.objectid + cache->key.offset;
+
+		spin_unlock(&root->fs_info->block_group_cache_lock);
+		btrfs_put_block_group(cache);
+		cache = btrfs_lookup_first_block_group(root->fs_info,
+						       next_bytenr);
+		return cache;
+	}
 	node = rb_next(&cache->cache_node);
 	btrfs_put_block_group(cache);
 	if (node) {
@@ -3504,6 +3516,7 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
 	found->chunk_alloc = 0;
 	found->flush = 0;
 	init_waitqueue_head(&found->wait);
+	INIT_LIST_HEAD(&found->ro_bgs);
 
 	ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
 				    info->space_info_kobj, "%s",
@@ -5425,7 +5438,17 @@ static int update_block_group(struct btrfs_root *root,
 			spin_unlock(&cache->space_info->lock);
 		} else {
 			old_val -= num_bytes;
+			btrfs_set_block_group_used(&cache->item, old_val);
+			cache->pinned += num_bytes;
+			cache->space_info->bytes_pinned += num_bytes;
+			cache->space_info->bytes_used -= num_bytes;
+			cache->space_info->disk_used -= num_bytes * factor;
+			spin_unlock(&cache->lock);
+			spin_unlock(&cache->space_info->lock);
 
+			set_extent_dirty(info->pinned_extents,
+					 bytenr, bytenr + num_bytes - 1,
+					 GFP_NOFS | __GFP_NOFAIL);
 			/*
 			 * No longer have used bytes in this block group, queue
 			 * it for deletion.
@@ -5439,17 +5462,6 @@ static int update_block_group(struct btrfs_root *root,
 				}
 				spin_unlock(&info->unused_bgs_lock);
 			}
-			btrfs_set_block_group_used(&cache->item, old_val);
-			cache->pinned += num_bytes;
-			cache->space_info->bytes_pinned += num_bytes;
-			cache->space_info->bytes_used -= num_bytes;
-			cache->space_info->disk_used -= num_bytes * factor;
-			spin_unlock(&cache->lock);
-			spin_unlock(&cache->space_info->lock);
-
-			set_extent_dirty(info->pinned_extents,
-					 bytenr, bytenr + num_bytes - 1,
-					 GFP_NOFS | __GFP_NOFAIL);
 		}
 		btrfs_put_block_group(cache);
 		total -= num_bytes;
@@ -8511,6 +8523,7 @@ static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
 	    min_allocable_bytes <= sinfo->total_bytes) {
 		sinfo->bytes_readonly += num_bytes;
 		cache->ro = 1;
+		list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
 		ret = 0;
 	}
 out:
@@ -8565,15 +8578,20 @@ int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
 
 /*
  * helper to account the unused space of all the readonly block group in the
- * list. takes mirrors into account.
+ * space_info. takes mirrors into account.
  */
-static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
+u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
 {
 	struct btrfs_block_group_cache *block_group;
 	u64 free_bytes = 0;
 	int factor;
 
-	list_for_each_entry(block_group, groups_list, list) {
+	/* It's df, we don't care if it's racey */
+	if (list_empty(&sinfo->ro_bgs))
+		return 0;
+
+	spin_lock(&sinfo->lock);
+	list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
 		spin_lock(&block_group->lock);
 
 		if (!block_group->ro) {
@@ -8594,26 +8612,6 @@ static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
 
 		spin_unlock(&block_group->lock);
 	}
-
-	return free_bytes;
-}
-
-/*
- * helper to account the unused space of all the readonly block group in the
- * space_info. takes mirrors into account.
- */
-u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
-{
-	int i;
-	u64 free_bytes = 0;
-
-	spin_lock(&sinfo->lock);
-
-	for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
-		if (!list_empty(&sinfo->block_groups[i]))
-			free_bytes += __btrfs_get_ro_block_group_free_space(
-						&sinfo->block_groups[i]);
-
 	spin_unlock(&sinfo->lock);
 
 	return free_bytes;
@@ -8633,6 +8631,7 @@ void btrfs_set_block_group_rw(struct btrfs_root *root,
 		    cache->bytes_super - btrfs_block_group_used(&cache->item);
 	sinfo->bytes_readonly -= num_bytes;
 	cache->ro = 0;
+	list_del_init(&cache->ro_list);
 	spin_unlock(&cache->lock);
 	spin_unlock(&sinfo->lock);
 }
@@ -9002,7 +9001,9 @@ btrfs_create_block_group_cache(struct btrfs_root *root, u64 start, u64 size)
 	INIT_LIST_HEAD(&cache->list);
 	INIT_LIST_HEAD(&cache->cluster_list);
 	INIT_LIST_HEAD(&cache->bg_list);
+	INIT_LIST_HEAD(&cache->ro_list);
 	btrfs_init_free_space_ctl(cache);
+	atomic_set(&cache->trimming, 0);
 
 	return cache;
 }
@@ -9195,9 +9196,8 @@ void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
 	int ret = 0;
 
 	list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
-		list_del_init(&block_group->bg_list);
 		if (ret)
-			continue;
+			goto next;
 
 		spin_lock(&block_group->lock);
 		memcpy(&item, &block_group->item, sizeof(item));
@@ -9212,6 +9212,8 @@ void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
 					       key.objectid, key.offset);
 		if (ret)
 			btrfs_abort_transaction(trans, extent_root, ret);
+next:
+		list_del_init(&block_group->bg_list);
 	}
 }
 
@@ -9304,7 +9306,8 @@ static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
 }
 
 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
-			     struct btrfs_root *root, u64 group_start)
+			     struct btrfs_root *root, u64 group_start,
+			     struct extent_map *em)
 {
 	struct btrfs_path *path;
 	struct btrfs_block_group_cache *block_group;
@@ -9316,6 +9319,8 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 	int ret;
 	int index;
 	int factor;
+	struct btrfs_caching_control *caching_ctl = NULL;
+	bool remove_em;
 
 	root = root->fs_info->extent_root;
 
@@ -9400,6 +9405,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 	spin_lock(&root->fs_info->block_group_cache_lock);
 	rb_erase(&block_group->cache_node,
 		 &root->fs_info->block_group_cache_tree);
+	RB_CLEAR_NODE(&block_group->cache_node);
 
 	if (root->fs_info->first_logical_byte == block_group->key.objectid)
 		root->fs_info->first_logical_byte = (u64)-1;
@@ -9411,6 +9417,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 	 * are still on the list after taking the semaphore
 	 */
 	list_del_init(&block_group->list);
+	list_del_init(&block_group->ro_list);
 	if (list_empty(&block_group->space_info->block_groups[index])) {
 		kobj = block_group->space_info->block_group_kobjs[index];
 		block_group->space_info->block_group_kobjs[index] = NULL;
@@ -9422,8 +9429,32 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 		kobject_put(kobj);
 	}
 
+	if (block_group->has_caching_ctl)
+		caching_ctl = get_caching_control(block_group);
 	if (block_group->cached == BTRFS_CACHE_STARTED)
 		wait_block_group_cache_done(block_group);
+	if (block_group->has_caching_ctl) {
+		down_write(&root->fs_info->commit_root_sem);
+		if (!caching_ctl) {
+			struct btrfs_caching_control *ctl;
+
+			list_for_each_entry(ctl,
+				    &root->fs_info->caching_block_groups, list)
+				if (ctl->block_group == block_group) {
+					caching_ctl = ctl;
+					atomic_inc(&caching_ctl->count);
+					break;
+				}
+		}
+		if (caching_ctl)
+			list_del_init(&caching_ctl->list);
+		up_write(&root->fs_info->commit_root_sem);
+		if (caching_ctl) {
+			/* Once for the caching bgs list and once for us. */
+			put_caching_control(caching_ctl);
+			put_caching_control(caching_ctl);
+		}
+	}
 
 	btrfs_remove_free_space_cache(block_group);
 
@@ -9435,6 +9466,71 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 
 	memcpy(&key, &block_group->key, sizeof(key));
 
+	lock_chunks(root);
+	if (!list_empty(&em->list)) {
+		/* We're in the transaction->pending_chunks list. */
+		free_extent_map(em);
+	}
+	spin_lock(&block_group->lock);
+	block_group->removed = 1;
+	/*
+	 * At this point trimming can't start on this block group, because we
+	 * removed the block group from the tree fs_info->block_group_cache_tree
+	 * so no one can't find it anymore and even if someone already got this
+	 * block group before we removed it from the rbtree, they have already
+	 * incremented block_group->trimming - if they didn't, they won't find
+	 * any free space entries because we already removed them all when we
+	 * called btrfs_remove_free_space_cache().
+	 *
+	 * And we must not remove the extent map from the fs_info->mapping_tree
+	 * to prevent the same logical address range and physical device space
+	 * ranges from being reused for a new block group. This is because our
+	 * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
+	 * completely transactionless, so while it is trimming a range the
+	 * currently running transaction might finish and a new one start,
+	 * allowing for new block groups to be created that can reuse the same
+	 * physical device locations unless we take this special care.
+	 */
+	remove_em = (atomic_read(&block_group->trimming) == 0);
+	/*
+	 * Make sure a trimmer task always sees the em in the pinned_chunks list
+	 * if it sees block_group->removed == 1 (needs to lock block_group->lock
+	 * before checking block_group->removed).
+	 */
+	if (!remove_em) {
+		/*
+		 * Our em might be in trans->transaction->pending_chunks which
+		 * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
+		 * and so is the fs_info->pinned_chunks list.
+		 *
+		 * So at this point we must be holding the chunk_mutex to avoid
+		 * any races with chunk allocation (more specifically at
+		 * volumes.c:contains_pending_extent()), to ensure it always
+		 * sees the em, either in the pending_chunks list or in the
+		 * pinned_chunks list.
+		 */
+		list_move_tail(&em->list, &root->fs_info->pinned_chunks);
+	}
+	spin_unlock(&block_group->lock);
+
+	if (remove_em) {
+		struct extent_map_tree *em_tree;
+
+		em_tree = &root->fs_info->mapping_tree.map_tree;
+		write_lock(&em_tree->lock);
+		/*
+		 * The em might be in the pending_chunks list, so make sure the
+		 * chunk mutex is locked, since remove_extent_mapping() will
+		 * delete us from that list.
+		 */
+		remove_extent_mapping(em_tree, em);
+		write_unlock(&em_tree->lock);
+		/* once for the tree */
+		free_extent_map(em);
+	}
+
+	unlock_chunks(root);
+
 	btrfs_put_block_group(block_group);
 	btrfs_put_block_group(block_group);
 
@@ -9523,10 +9619,18 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
 		 */
 		start = block_group->key.objectid;
 		end = start + block_group->key.offset - 1;
-		clear_extent_bits(&fs_info->freed_extents[0], start, end,
+		ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
 				  EXTENT_DIRTY, GFP_NOFS);
-		clear_extent_bits(&fs_info->freed_extents[1], start, end,
+		if (ret) {
+			btrfs_set_block_group_rw(root, block_group);
+			goto end_trans;
+		}
+		ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
 				  EXTENT_DIRTY, GFP_NOFS);
+		if (ret) {
+			btrfs_set_block_group_rw(root, block_group);
+			goto end_trans;
+		}
 
 		/* Reset pinned so btrfs_put_block_group doesn't complain */
 		block_group->pinned = 0;
@@ -9537,6 +9641,7 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
 		 */
 		ret = btrfs_remove_chunk(trans, root,
 					 block_group->key.objectid);
+end_trans:
 		btrfs_end_transaction(trans, root);
 next:
 		btrfs_put_block_group(block_group);
@@ -9657,12 +9762,14 @@ int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
 }
 
 /*
- * btrfs_{start,end}_write() is similar to mnt_{want, drop}_write(),
- * they are used to prevent the some tasks writing data into the page cache
- * by nocow before the subvolume is snapshoted, but flush the data into
- * the disk after the snapshot creation.
+ * btrfs_{start,end}_write_no_snapshoting() are similar to
+ * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
+ * data into the page cache through nocow before the subvolume is snapshoted,
+ * but flush the data into disk after the snapshot creation, or to prevent
+ * operations while snapshoting is ongoing and that cause the snapshot to be
+ * inconsistent (writes followed by expanding truncates for example).
  */
-void btrfs_end_nocow_write(struct btrfs_root *root)
+void btrfs_end_write_no_snapshoting(struct btrfs_root *root)
 {
 	percpu_counter_dec(&root->subv_writers->counter);
 	/*
@@ -9674,7 +9781,7 @@ void btrfs_end_nocow_write(struct btrfs_root *root)
 		wake_up(&root->subv_writers->wait);
 }
 
-int btrfs_start_nocow_write(struct btrfs_root *root)
+int btrfs_start_write_no_snapshoting(struct btrfs_root *root)
 {
 	if (atomic_read(&root->will_be_snapshoted))
 		return 0;
@@ -9685,7 +9792,7 @@ int btrfs_start_nocow_write(struct btrfs_root *root)
 	 */
 	smp_mb();
 	if (atomic_read(&root->will_be_snapshoted)) {
-		btrfs_end_nocow_write(root);
+		btrfs_end_write_no_snapshoting(root);
 		return 0;
 	}
 	return 1;