ext4: endless truncate due to nonlocked dio readers
If we have enough aggressive DIO readers, truncate and other dio
waiters will wait forever inside inode_dio_wait(). It is reasonable
to disable nonlock DIO read optimization during truncate.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 0bfc633..05ab70d 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4333,9 +4333,14 @@
if (attr->ia_valid & ATTR_SIZE) {
if (attr->ia_size != i_size_read(inode)) {
truncate_setsize(inode, attr->ia_size);
- /* Inode size will be reduced, wait for dio in flight */
- if (orphan)
+ /* Inode size will be reduced, wait for dio in flight.
+ * Temporarily disable dioread_nolock to prevent
+ * livelock. */
+ if (orphan) {
+ ext4_inode_block_unlocked_dio(inode);
inode_dio_wait(inode);
+ ext4_inode_resume_unlocked_dio(inode);
+ }
}
ext4_truncate(inode);
}