ceph: handle race between vmtruncate and queuing cap snap

It's possible that we create a cap snap while there is pending
vmtruncate (truncate hasn't been processed by worker thread).
We should truncate dirty pages beyond capsnap->size in that case.

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This commit is contained in:
Yan, Zheng 2017-08-28 15:41:28 +08:00 committed by Ilya Dryomov
parent fa0aa3b839
commit c8fd0d37f8

View File

@ -1833,9 +1833,20 @@ retry:
* possibly truncate them.. so write AND block!
*/
if (ci->i_wrbuffer_ref_head < ci->i_wrbuffer_ref) {
struct ceph_cap_snap *capsnap;
to = ci->i_truncate_size;
list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
// MDS should have revoked Frw caps
WARN_ON_ONCE(capsnap->writing);
if (capsnap->dirty_pages && capsnap->size > to)
to = capsnap->size;
}
spin_unlock(&ci->i_ceph_lock);
dout("__do_pending_vmtruncate %p flushing snaps first\n",
inode);
spin_unlock(&ci->i_ceph_lock);
truncate_pagecache(inode, to);
filemap_write_and_wait_range(&inode->i_data, 0,
inode->i_sb->s_maxbytes);
goto retry;