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

Pull the minimal btrfs branch from Chris Mason:
 "We have a use-after-free in there, along with errors when mount -o
  discard is enabled, and a BUG_ON(we should compile with UP more
  often)."

* 'for-linus-min' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: use commit root when loading free space cache
  Btrfs: fix use-after-free in __btrfs_end_transaction
  Btrfs: check return value of bio_alloc() properly
  Btrfs: remove lock assert from get_restripe_target()
  Btrfs: fix eof while discarding extents
  Btrfs: fix uninit variable in repair_eb_io_failure
  Revert "Btrfs: increase the global block reserve estimates"

Author: torvalds

fs/btrfs/compression.c

@@ -405,6 +405,7 @@ int btrfs_submit_compressed_write(struct inode *inode, u64 start,
 			bio_put(bio);
 
 			bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS);
+			BUG_ON(!bio);
 			bio->bi_private = cb;
 			bio->bi_end_io = end_compressed_bio_write;
 			bio_add_page(bio, page, PAGE_CACHE_SIZE, 0);
@@ -687,6 +688,7 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
 
 			comp_bio = compressed_bio_alloc(bdev, cur_disk_byte,
 							GFP_NOFS);
+			BUG_ON(!comp_bio);
 			comp_bio->bi_private = cb;
 			comp_bio->bi_end_io = end_compressed_bio_read;
 

fs/btrfs/extent-tree.c

@@ -529,9 +529,7 @@ static int cache_block_group(struct btrfs_block_group_cache *cache,
 	 * allocate blocks for the tree root we can't do the fast caching since
 	 * we likely hold important locks.
 	 */
-	if (trans && (!trans->transaction->in_commit) &&
-	    (root && root != root->fs_info->tree_root) &&
-	    btrfs_test_opt(root, SPACE_CACHE)) {
+	if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 		ret = load_free_space_cache(fs_info, cache);
 
 		spin_lock(&cache->lock);
@@ -3152,15 +3150,14 @@ static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
 /*
  * returns target flags in extended format or 0 if restripe for this
  * chunk_type is not in progress
+ *
+ * should be called with either volume_mutex or balance_lock held
  */
 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
 {
 	struct btrfs_balance_control *bctl = fs_info->balance_ctl;
 	u64 target = 0;
 
-	BUG_ON(!mutex_is_locked(&fs_info->volume_mutex) &&
-	       !spin_is_locked(&fs_info->balance_lock));
-
 	if (!bctl)
 		return 0;
 
@@ -4205,7 +4202,7 @@ static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
 	num_bytes += div64_u64(data_used + meta_used, 50);
 
 	if (num_bytes * 3 > meta_used)
-		num_bytes = div64_u64(meta_used, 3) * 2;
+		num_bytes = div64_u64(meta_used, 3);
 
 	return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
 }

fs/btrfs/extent_io.c

@@ -1937,7 +1937,7 @@ int repair_eb_io_failure(struct btrfs_root *root, struct extent_buffer *eb,
 	struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
 	u64 start = eb->start;
 	unsigned long i, num_pages = num_extent_pages(eb->start, eb->len);
-	int ret;
+	int ret = 0;
 
 	for (i = 0; i < num_pages; i++) {
 		struct page *p = extent_buffer_page(eb, i);
@@ -2180,6 +2180,10 @@ static int bio_readpage_error(struct bio *failed_bio, struct page *page,
 	}
 
 	bio = bio_alloc(GFP_NOFS, 1);
+	if (!bio) {
+		free_io_failure(inode, failrec, 0);
+		return -EIO;
+	}
 	bio->bi_private = state;
 	bio->bi_end_io = failed_bio->bi_end_io;
 	bio->bi_sector = failrec->logical >> 9;

fs/btrfs/free-space-cache.c

@@ -747,13 +747,6 @@ int load_free_space_cache(struct btrfs_fs_info *fs_info,
 	bool matched;
 	u64 used = btrfs_block_group_used(&block_group->item);
 
-	/*
-	 * If we're unmounting then just return, since this does a search on the
-	 * normal root and not the commit root and we could deadlock.
-	 */
-	if (btrfs_fs_closing(fs_info))
-		return 0;
-
 	/*
 	 * If this block group has been marked to be cleared for one reason or
 	 * another then we can't trust the on disk cache, so just return.
@@ -768,6 +761,8 @@ int load_free_space_cache(struct btrfs_fs_info *fs_info,
 	path = btrfs_alloc_path();
 	if (!path)
 		return 0;
+	path->search_commit_root = 1;
+	path->skip_locking = 1;
 
 	inode = lookup_free_space_inode(root, block_group, path);
 	if (IS_ERR(inode)) {

fs/btrfs/scrub.c

@@ -1044,6 +1044,8 @@ static int scrub_recheck_block(struct btrfs_fs_info *fs_info,
 
 		BUG_ON(!page->page);
 		bio = bio_alloc(GFP_NOFS, 1);
+		if (!bio)
+			return -EIO;
 		bio->bi_bdev = page->bdev;
 		bio->bi_sector = page->physical >> 9;
 		bio->bi_end_io = scrub_complete_bio_end_io;
@@ -1171,6 +1173,8 @@ static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
 		DECLARE_COMPLETION_ONSTACK(complete);
 
 		bio = bio_alloc(GFP_NOFS, 1);
+		if (!bio)
+			return -EIO;
 		bio->bi_bdev = page_bad->bdev;
 		bio->bi_sector = page_bad->physical >> 9;
 		bio->bi_end_io = scrub_complete_bio_end_io;

fs/btrfs/transaction.c

@@ -480,6 +480,7 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
 	struct btrfs_transaction *cur_trans = trans->transaction;
 	struct btrfs_fs_info *info = root->fs_info;
 	int count = 0;
+	int err = 0;
 
 	if (--trans->use_count) {
 		trans->block_rsv = trans->orig_rsv;
@@ -532,18 +533,18 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
 
 	if (current->journal_info == trans)
 		current->journal_info = NULL;
-	memset(trans, 0, sizeof(*trans));
-	kmem_cache_free(btrfs_trans_handle_cachep, trans);
 
 	if (throttle)
 		btrfs_run_delayed_iputs(root);
 
 	if (trans->aborted ||
 	    root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
-		return -EIO;
+		err = -EIO;
 	}
 
-	return 0;
+	memset(trans, 0, sizeof(*trans));
+	kmem_cache_free(btrfs_trans_handle_cachep, trans);
+	return err;
 }
 
 int btrfs_end_transaction(struct btrfs_trans_handle *trans,

fs/btrfs/volumes.c

@@ -3833,6 +3833,7 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
 		int sub_stripes = 0;
 		u64 stripes_per_dev = 0;
 		u32 remaining_stripes = 0;
+		u32 last_stripe = 0;
 
 		if (map->type &
 		    (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
@@ -3846,6 +3847,8 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
 						      stripe_nr_orig,
 						      factor,
 						      &remaining_stripes);
+			div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
+			last_stripe *= sub_stripes;
 		}
 
 		for (i = 0; i < num_stripes; i++) {
@@ -3858,16 +3861,29 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
 					 BTRFS_BLOCK_GROUP_RAID10)) {
 				bbio->stripes[i].length = stripes_per_dev *
 							  map->stripe_len;
+
 				if (i / sub_stripes < remaining_stripes)
 					bbio->stripes[i].length +=
 						map->stripe_len;
+
+				/*
+				 * Special for the first stripe and
+				 * the last stripe:
+				 *
+				 * |-------|...|-------|
+				 *     |----------|
+				 *    off     end_off
+				 */
 				if (i < sub_stripes)
 					bbio->stripes[i].length -=
 						stripe_offset;
-				if ((i / sub_stripes + 1) %
-				    sub_stripes == remaining_stripes)
+
+				if (stripe_index >= last_stripe &&
+				    stripe_index <= (last_stripe +
+						     sub_stripes - 1))
 					bbio->stripes[i].length -=
 						stripe_end_offset;
+
 				if (i == sub_stripes - 1)
 					stripe_offset = 0;
 			} else