unsigned long flags;
int ret;
- mutex_lock(&inode->i_mutex);
+ if (!mutex_trylock(&inode->i_mutex)) {
+ /*
+ * Requeue the work instead of waiting so that the work
+ * items queued after this can be processed.
+ */
+ queue_work(EXT4_SB(inode->i_sb)->dio_unwritten_wq, &io->work);
+ /*
+ * To prevent the ext4-dio-unwritten thread from keeping
+ * requeueing end_io requests and occupying cpu for too long,
+ * yield the cpu if it sees an end_io request that has already
+ * been requeued.
+ */
+ if (io->flag & EXT4_IO_END_QUEUED)
+ yield();
+ io->flag |= EXT4_IO_END_QUEUED;
+ return;
+ }
ret = ext4_end_io_nolock(io);
if (ret < 0) {
mutex_unlock(&inode->i_mutex);