ceph: handle -EAGAIN returned by ceph_update_writeable_page()

when ceph_update_writeable_page() return -EAGAIN, caller should
lock the page and call ceph_update_writeable_page() again.

Signed-off-by: Yan, Zheng <zyan@redhat.com>

1 files changed, 15 insertions, 13 deletions

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index d128bb65746d..97ee5d1fbb61 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1475,21 +1475,23 @@ static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
         /* Update time before taking page lock */
         file_update_time(vma->vm_file);
 
-        lock_page(page);
+        do {
+                lock_page(page);
 
-        if ((off > size) || (page->mapping != inode->i_mapping)) {
-                unlock_page(page);
-                ret = VM_FAULT_NOPAGE;
-                goto out;
-        }
+                if ((off > size) || (page->mapping != inode->i_mapping)) {
+                        unlock_page(page);
+                        ret = VM_FAULT_NOPAGE;
+                        break;
+                }
+
+                ret = ceph_update_writeable_page(vma->vm_file, off, len, page);
+                if (ret >= 0) {
+                        /* success.  we'll keep the page locked. */
+                        set_page_dirty(page);
+                        ret = VM_FAULT_LOCKED;
+                }
+        } while (ret == -EAGAIN);
 
-        ret = ceph_update_writeable_page(vma->vm_file, off, len, page);
-        if (ret >= 0) {
-                /* success.  we'll keep the page locked. */
-                set_page_dirty(page);
-                ret = VM_FAULT_LOCKED;
-        }
-out:
         if (ret == VM_FAULT_LOCKED ||
             ci->i_inline_version != CEPH_INLINE_NONE) {
                 int dirty;