Hi Ben, ocfs2_dio_end_io_write() was introduced in 4.6 and the problem this patch fixes is only exist in the kernel 4.6 and above 4.6.
Thanks, Alex On 2018/2/11 12:20, Ben Hutchings wrote: > 3.2.99-rc1 review patch. If anyone has any objections, please let me know. > > ------------------ > > From: alex chen <alex.c...@huawei.com> > > commit 28f5a8a7c033cbf3e32277f4cc9c6afd74f05300 upstream. > > 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/59f81636.70...@huawei.com > Signed-off-by: Alex Chen <alex.c...@huawei.com> > Reviewed-by: Jun Piao <piao...@huawei.com> > Reviewed-by: Joseph Qi <jiangqi...@gmail.com> > Acked-by: Changwei Ge <ge.chang...@h3c.com> > Cc: Mark Fasheh <mfas...@versity.com> > Cc: Joel Becker <jl...@evilplan.org> > Cc: Junxiao Bi <junxiao...@oracle.com> > Signed-off-by: Andrew Morton <a...@linux-foundation.org> > Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> > Signed-off-by: Ben Hutchings <b...@decadent.org.uk> > --- > fs/ocfs2/file.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > --- a/fs/ocfs2/file.c > +++ b/fs/ocfs2/file.c > @@ -1130,6 +1130,13 @@ int ocfs2_setattr(struct dentry *dentry, > dquot_initialize(inode); > 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); > @@ -1149,8 +1156,6 @@ 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, > > > . >
