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>

4 files changed, 18 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 {
diff --git a/fs/ceph/ioctl.c b/fs/ceph/ioctl.c
index ef0b5f48e13a..a757a5680578 100644
--- a/fs/ceph/ioctl.c
+++ b/fs/ceph/ioctl.c
@@ -231,6 +231,14 @@ static long ceph_ioctl_lazyio(struct file *file)
         return 0;
 }
 
+static long ceph_ioctl_syncio(struct file *file)
+{
+        struct ceph_file_info *fi = file->private_data;
+
+        fi->flags |= CEPH_F_SYNC;
+        return 0;
+}
+
 long ceph_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
         dout("ioctl file %p cmd %u arg %lu\n", file, cmd, arg);
@@ -249,6 +257,9 @@ long ceph_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 
         case CEPH_IOC_LAZYIO:
                 return ceph_ioctl_lazyio(file);
+
+        case CEPH_IOC_SYNCIO:
+                return ceph_ioctl_syncio(file);
         }
 
         return -ENOTTY;
diff --git a/fs/ceph/ioctl.h b/fs/ceph/ioctl.h
index 52e8fd74d450..0c5167e43180 100644
--- a/fs/ceph/ioctl.h
+++ b/fs/ceph/ioctl.h
@@ -40,5 +40,6 @@ struct ceph_ioctl_dataloc {
                                    struct ceph_ioctl_dataloc)
 
 #define CEPH_IOC_LAZYIO _IO(CEPH_IOCTL_MAGIC, 4)
+#define CEPH_IOC_SYNCIO _IO(CEPH_IOCTL_MAGIC, 5)
 
 #endif
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 8febe6fce2b1..cdb17d36755c 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -543,6 +543,8 @@ extern void ceph_reservation_status(struct ceph_fs_client *client,
 /*
  * we keep buffered readdir results attached to file->private_data
  */
+#define CEPH_F_SYNC     1
+
 struct ceph_file_info {
         short fmode;     /* initialized on open */
         short flags;     /* CEPH_F_* */