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authorJosef Bacik <jbacik@fb.com>2016-07-20 16:48:45 -0700
committerChris Mason <clm@fb.com>2016-07-20 16:58:04 -0700
commitbac357dcec2956f01df9da5365be257741b534dc (patch)
treef696c4ea2ce8b51c9fe58f9bd5c6411693f7fc2d /fs/btrfs
parent24502ebb606baa87ba7b9a097a88398bd6edd2f4 (diff)
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: Chris Mason <clm@fb.com> Signed-off-by: Josef Bacik <jbacik@fb.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/extent-tree.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 3a129c42658e..9fcb8c97083b 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -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 &&