nfsd: fix bad offset use

commit e49dbbf3e770aa590a8a464ac4978a09027060b9 upstream.

vfs_writev() updates the offset argument - but the code then passes the
offset to vfs_fsync_range(). Since offset now points to the offset after
what was just written, this is probably not what was intended

Introduced by face15025ffdf664de95e86ae831544154d26c9c "nfsd: use
vfs_fsync_range(), not O_SYNC, for stable writes".

Signed-off-by: Kent Overstreet <koverstreet@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Reviewed-by: Zach Brown <zab@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index d586117fa94a74f07105055bc053746bfa90bdfb..69c641348f12ab74434de3939769529d68ca785e 100644 (file)
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1013,6 +1013,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
        int                     host_err;
        int                     stable = *stablep;
        int                     use_wgather;
+       loff_t                  pos = offset;
 
        dentry = file->f_path.dentry;
        inode = dentry->d_inode;
@@ -1025,7 +1026,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 
        /* Write the data. */
        oldfs = get_fs(); set_fs(KERNEL_DS);
-       host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &offset);
+       host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &pos);
        set_fs(oldfs);
        if (host_err < 0)
                goto out_nfserr;