From: Yunchuan Wen <yunchuan...@ubuntukylin.com> The following scripts could easily panic the kernel,
#!/bin/bash mount -t ceph -o fsc MONADDR:/ cephfs rm -rf cephfs/foo dd if=/dev/zero of=cephfs/foo bs=8 count=512 echo 3 > /proc/sys/vm/drop_caches dd if=cephfs/foo of=/dev/null bs=8 count=1024 This is due to when writing a page into fscache, the code will assert that the write position does not exceed the object->store_limit_l, which is supposed to be equal to inode->i_size. However, for current implementation, after file writing, the object->store_limit_l is not synchronized with new inode->i_size immediately, which introduces a race that if writing a new page into fscache, will reach the ASSERT that write position has exceeded the object->store_limit_l, and cause kernel panic. This patch fixes it. Yunchuan Wen (3): Ceph fscache: Add an interface to synchronize object store limit Ceph fscache: Update object store limit after writing Ceph fscache: Wait for completion of object initialization fs/ceph/cache.c | 1 + fs/ceph/cache.h | 10 ++++++++++ fs/ceph/file.c | 3 +++ 3 files changed, 14 insertions(+) -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
