ceph: add F_SYNC file flag to force sync (non-O_DIRECT) io

This allows us to force IO through the sync path which you normally only
get when multiple clients are reading/writing to the same file or by
mounting with -o sync.  Among other things, this lets test programs verify
correctness with a single mount.

Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>

1 files changed, 4 insertions, 2 deletions

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 4698a5c553dc..44e4fe9fba02 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -643,7 +643,8 @@ again:
 
         if ((got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0 ||
             (iocb->ki_filp->f_flags & O_DIRECT) ||
-            (inode->i_sb->s_flags & MS_SYNCHRONOUS))
+            (inode->i_sb->s_flags & MS_SYNCHRONOUS) ||
+            (fi->flags & CEPH_F_SYNC))
                 /* hmm, this isn't really async... */
                 ret = ceph_sync_read(filp, base, len, ppos, &checkeof);
         else
@@ -720,7 +721,8 @@ retry_snap:
 
         if ((got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO)) == 0 ||
             (iocb->ki_filp->f_flags & O_DIRECT) ||
-            (inode->i_sb->s_flags & MS_SYNCHRONOUS)) {
+            (inode->i_sb->s_flags & MS_SYNCHRONOUS) ||
+            (fi->flags & CEPH_F_SYNC)) {
                 ret = ceph_sync_write(file, iov->iov_base, iov->iov_len,
                         &iocb->ki_pos);
         } else {