nfsd: use vfs_fsync_range(), not O_SYNC, for stable writes

NFSv4 shares the same struct file across multiple writes.  (And we'd
like NFSv2 and NFSv3 to do that as well some day.)

So setting O_SYNC on the struct file as a way to request a synchronous
write doesn't work.

Instead, do a vfs_fsync_range() in that case.

Reported-by: Peter Staubach <pstaubach@exagrid.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index ed3eb59b607eb18a695a5ec7a870f55fac02b863..b584205b25b41d66558f5ae8408242edb24fb670 100644 (file)
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1024,11 +1024,6 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 
        if (!EX_ISSYNC(exp))
                stable = 0;
-       if (stable && !use_wgather) {
-               spin_lock(&file->f_lock);
-               file->f_flags |= O_SYNC;
-               spin_unlock(&file->f_lock);
-       }
 
        /* Write the data. */
        oldfs = get_fs(); set_fs(KERNEL_DS);
@@ -1044,8 +1039,12 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
        if (inode->i_mode & (S_ISUID | S_ISGID))
                kill_suid(dentry);
 
-       if (stable && use_wgather)
-               host_err = wait_for_concurrent_writes(file);
+       if (stable) {
+               if (use_wgather)
+                       host_err = wait_for_concurrent_writes(file);
+               else
+                       host_err = vfs_fsync_range(file, offset, offset+*cnt, 0);
+       }
 
 out_nfserr:
        dprintk("nfsd: write complete host_err=%d\n", host_err);