Commits
Jan Kara committed c7e25e6e0b0
ocfs2: Avoid livelock in ocfs2_readpage() When someone writes to an inode, readers accessing the same inode via ocfs2_readpage() just busyloop trying to get ip_alloc_sem because do_generic_file_read() looks up the page again and retries ->readpage() when previous attempt failed with AOP_TRUNCATED_PAGE. When there are enough readers, they can occupy all CPUs and in non-preempt kernel the system is deadlocked because writer holding ip_alloc_sem is never run to release the semaphore. Fix the problem by making reader block on ip_alloc_sem to break the busy loop. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Joel Becker <jlbec@evilplan.org>