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>

1 files changed, 32 insertions, 18 deletions

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 03a1ee27b33c..8526359c08b2 100644
--- 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",