ext2: fix unbalanced kmap()/kunmap()
In ext2_rename(), dir_page is acquired through ext2_dotdot(). It is then released through ext2_set_link() but only if old_dir != new_dir. Failing that, the pkmap reference count is never decremented and the page remains pinned forever. Repeat that a couple times with highmem pages and all pkmap slots get exhausted, and every further kmap() calls end up stalling on the pkmap_map_wait queue at which point the whole system comes to a halt. Signed-off-by: NNicolas Pitre <nico@marvell.com> Acked-by: NTheodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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