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Commit bac357dc authored by Josef Bacik's avatar Josef Bacik Committed by Chris Mason
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Btrfs: avoid deadlocks during reservations in btrfs_truncate_block 



The new enospc code makes it possible to deadlock if we don't use
FLUSH_LIMIT during reservations inside a transaction.  This enforces
the correct flush type to avoid both deadlocks and assertions

Signed-off-by: default avatarChris Mason <clm@fb.com>
Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
parent 24502ebb

fs/btrfs/extent-tree.c

+5 −0
Original line number Diff line number Diff line
@@ -5939,10 +5939,15 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes) 
	 * the middle of a transaction commit.  We also don't need the delalloc

	 * mutex since we won't race with anybody.  We need this mostly to make

	 * lockdep shut its filthy mouth.

	 *

	 * If we have a transaction open (can happen if we call truncate_block

	 * from truncate), then we need FLUSH_LIMIT so we don't deadlock.

	 */

	if (btrfs_is_free_space_inode(inode)) {

		flush = BTRFS_RESERVE_NO_FLUSH;

		delalloc_lock = false;

	} else if (current->journal_info) {

		flush = BTRFS_RESERVE_FLUSH_LIMIT;

	}



	if (flush != BTRFS_RESERVE_NO_FLUSH &&