ceph: don't early drop Fw cap

ceph_aio_write() has an optimization that marks CEPH_CAP_FILE_WR
cap dirty before data is copied to page cache and inode size is
updated. The optimization avoids slow cap revocation caused by
balance_dirty_pages(), but introduces inode size update race. If
ceph_check_caps() flushes the dirty cap before the inode size is
updated, MDS can miss the new inode size. So just remove the
optimization.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Greg Farnum <greg@inktank.com>

1 files changed, 17 insertions, 25 deletions

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index b86d2a0eb145..3d1aefeee948 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -724,9 +724,12 @@ static ssize_t ceph_aio_write(struct kiocb *iocb, const struct iovec *iov,
         if (ceph_snap(inode) != CEPH_NOSNAP)
                 return -EROFS;
 
+        sb_start_write(inode->i_sb);
 retry_snap:
-        if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL))
-                return -ENOSPC;
+        if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL)) {
+                ret = -ENOSPC;
+                goto out;
+        }
         __ceph_do_pending_vmtruncate(inode);
         dout("aio_write %p %llx.%llx %llu~%u getting caps. i_size %llu\n",
              inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
@@ -750,29 +753,10 @@ retry_snap:
                 ret = ceph_sync_write(file, iov->iov_base, iov->iov_len,
                         &iocb->ki_pos);
         } else {
-                /*
-                 * buffered write; drop Fw early to avoid slow
-                 * revocation if we get stuck on balance_dirty_pages
-                 */
-                int dirty;
-
-                spin_lock(&ci->i_ceph_lock);
-                dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
-                spin_unlock(&ci->i_ceph_lock);
-                ceph_put_cap_refs(ci, got);
-
-                ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
-                if ((ret >= 0 || ret == -EIOCBQUEUED) &&
-                    ((file->f_flags & O_SYNC) || IS_SYNC(file->f_mapping->host)
-                     || ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_NEARFULL))) {
-                        err = vfs_fsync_range(file, pos, pos + ret - 1, 1);
-                        if (err < 0)
-                                ret = err;
-                }
-
-                if (dirty)
-                        __mark_inode_dirty(inode, dirty);
-                goto out;
+                mutex_lock(&inode->i_mutex);
+                ret = __generic_file_aio_write(iocb, iov, nr_segs,
+                                               &iocb->ki_pos);
+                mutex_unlock(&inode->i_mutex);
         }
 
         if (ret >= 0) {
@@ -790,12 +774,20 @@ out_put:
              ceph_cap_string(got));
         ceph_put_cap_refs(ci, got);
 
+        if (ret >= 0 &&
+            ((file->f_flags & O_SYNC) || IS_SYNC(file->f_mapping->host) ||
+             ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_NEARFULL))) {
+                err = vfs_fsync_range(file, pos, pos + ret - 1, 1);
+                if (err < 0)
+                        ret = err;
+        }
 out:
         if (ret == -EOLDSNAPC) {
                 dout("aio_write %p %llx.%llx %llu~%u got EOLDSNAPC, retrying\n",
                      inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len);
                 goto retry_snap;
         }
+        sb_end_write(inode->i_sb);
 
         return ret;
 }