From: alex chen alex.chen@huawei.com Subject: ocfs2: should wait dio before inode lock in ocfs2_setattr()
we should wait dio requests to finish before inode lock in ocfs2_setattr(), otherwise the following deadlock will happen:
process 1 process 2 process 3 truncate file 'A' end_io of writing file 'A' receiving the bast messages ocfs2_setattr ocfs2_inode_lock_tracker ocfs2_inode_lock_full inode_dio_wait __inode_dio_wait -->waiting for all dio requests finish dlm_proxy_ast_handler dlm_do_local_bast ocfs2_blocking_ast ocfs2_generic_handle_bast set OCFS2_LOCK_BLOCKED flag dio_end_io dio_bio_end_aio dio_complete ocfs2_dio_end_io ocfs2_dio_end_io_write ocfs2_inode_lock __ocfs2_cluster_lock ocfs2_wait_for_mask -->waiting for OCFS2_LOCK_BLOCKED flag to be cleared, that is waiting for 'process 1' unlocking the inode lock inode_dio_end -->here dec the i_dio_count, but will never be called, so a deadlock happened.
Link: http://lkml.kernel.org/r/59F81636.70508@huawei.com Signed-off-by: Alex Chen alex.chen@huawei.com Reviewed-by: Jun Piao piaojun@huawei.com Reviewed-by: Joseph Qi jiangqi903@gmail.com Acked-by: Changwei Ge ge.changwei@h3c.com Cc: Mark Fasheh mfasheh@versity.com Cc: Joel Becker jlbec@evilplan.org Cc: Junxiao Bi junxiao.bi@oracle.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
fs/ocfs2/file.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff -puN fs/ocfs2/file.c~ocfs2-should-wait-dio-before-inode-lock-in-ocfs2_setattr fs/ocfs2/file.c --- a/fs/ocfs2/file.c~ocfs2-should-wait-dio-before-inode-lock-in-ocfs2_setattr +++ a/fs/ocfs2/file.c @@ -1161,6 +1161,13 @@ int ocfs2_setattr(struct dentry *dentry, } size_change = S_ISREG(inode->i_mode) && attr->ia_valid & ATTR_SIZE; if (size_change) { + /* + * Here we should wait dio to finish before inode lock + * to avoid a deadlock between ocfs2_setattr() and + * ocfs2_dio_end_io_write() + */ + inode_dio_wait(inode); + status = ocfs2_rw_lock(inode, 1); if (status < 0) { mlog_errno(status); @@ -1200,8 +1207,6 @@ int ocfs2_setattr(struct dentry *dentry, if (status) goto bail_unlock;
- inode_dio_wait(inode); - if (i_size_read(inode) >= attr->ia_size) { if (ocfs2_should_order_data(inode)) { status = ocfs2_begin_ordered_truncate(inode, _