ceph: make writepage_nounlock() invalidate page that beyonds EOF

Otherwise, the page left in state that page is associated with a
snapc, but (PageDirty(page) || PageWriteback(page)) is false.

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 03a1ee27b33cf35c8af04bfe5a9952a7dc6f0e02..8526359c08b27034327a692db320b7c75bce94b4 100644 (file)
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -476,7 +476,8 @@ struct ceph_writeback_ctl
  * only snap context we are allowed to write back.
  */
 static struct ceph_snap_context *
-get_oldest_context(struct inode *inode, struct ceph_writeback_ctl *ctl)
+get_oldest_context(struct inode *inode, struct ceph_writeback_ctl *ctl,
+                  struct ceph_snap_context *page_snapc)
 {
        struct ceph_inode_info *ci = ceph_inode(inode);
        struct ceph_snap_context *snapc = NULL;
@@ -486,21 +487,33 @@ get_oldest_context(struct inode *inode, struct ceph_writeback_ctl *ctl)
        list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
                dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,
                     capsnap->context, capsnap->dirty_pages);
-               if (capsnap->dirty_pages) {
-                       snapc = ceph_get_snap_context(capsnap->context);
-                       if (ctl) {
-                               if (capsnap->writing) {
-                                       ctl->i_size = i_size_read(inode);
-                                       ctl->size_stable = false;
-                               } else {
-                                       ctl->i_size = capsnap->size;
-                                       ctl->size_stable = true;
-                               }
-                               ctl->truncate_size = capsnap->truncate_size;
-                               ctl->truncate_seq = capsnap->truncate_seq;
+               if (!capsnap->dirty_pages)
+                       continue;
+
+               /* get i_size, truncate_{seq,size} for page_snapc? */
+               if (snapc && capsnap->context != page_snapc)
+                       continue;
+
+               if (ctl) {
+                       if (capsnap->writing) {
+                               ctl->i_size = i_size_read(inode);
+                               ctl->size_stable = false;
+                       } else {
+                               ctl->i_size = capsnap->size;
+                               ctl->size_stable = true;
                        }
-                       break;
+                       ctl->truncate_size = capsnap->truncate_size;
+                       ctl->truncate_seq = capsnap->truncate_seq;
                }
+
+               if (snapc)
+                       break;
+
+               snapc = ceph_get_snap_context(capsnap->context);
+               if (!page_snapc ||
+                   page_snapc == snapc ||
+                   page_snapc->seq > snapc->seq)
+                       break;
        }
        if (!snapc && ci->i_wrbuffer_ref_head) {
                snapc = ceph_get_snap_context(ci->i_head_snapc);
@@ -573,7 +586,7 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
                dout("writepage %p page %p not dirty?\n", inode, page);
                return 0;
        }
-       oldest = get_oldest_context(inode, &ceph_wbc);
+       oldest = get_oldest_context(inode, &ceph_wbc, snapc);
        if (snapc->seq > oldest->seq) {
                dout("writepage %p page %p snapc %p not writeable - noop\n",
                     inode, page, snapc);
@@ -588,6 +601,7 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
        /* is this a partial page at end of file? */
        if (page_off >= ceph_wbc.i_size) {
                dout("%p page eof %llu\n", page, ceph_wbc.i_size);
+               page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
                return 0;
        }
 
@@ -816,7 +830,7 @@ static int ceph_writepages_start(struct address_space *mapping,
 retry:
        /* find oldest snap context with dirty data */
        ceph_put_snap_context(snapc);
-       snapc = get_oldest_context(inode, &ceph_wbc);
+       snapc = get_oldest_context(inode, &ceph_wbc, NULL);
        if (!snapc) {
                /* hmm, why does writepages get called when there
                   is no dirty data? */
@@ -1162,7 +1176,7 @@ out:
 static int context_is_writeable_or_written(struct inode *inode,
                                           struct ceph_snap_context *snapc)
 {
-       struct ceph_snap_context *oldest = get_oldest_context(inode, NULL);
+       struct ceph_snap_context *oldest = get_oldest_context(inode, NULL, NULL);
        int ret = !oldest || snapc->seq <= oldest->seq;
 
        ceph_put_snap_context(oldest);
@@ -1207,7 +1221,7 @@ retry_locked:
                 * this page is already dirty in another (older) snap
                 * context!  is it writeable now?
                 */
-               oldest = get_oldest_context(inode, NULL);
+               oldest = get_oldest_context(inode, NULL, NULL);
                if (snapc->seq > oldest->seq) {
                        ceph_put_snap_context(oldest);
                        dout(" page %p snapc %p not current or oldest\n",