[PATCH] splice: offset fixes

- We need to adjust *ppos for writes as well.
- Copy back modified offset value if one was passed in, similar to
  what sendfile does.

Signed-off-by: Jens Axboe <axboe@suse.de>

diff --git a/fs/splice.c b/fs/splice.c
index 4f5e6b0..27d6408 100644 (file)
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -720,22 +720,26 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
        ssize_t ret;
 
        ret = move_from_pipe(pipe, out, ppos, len, flags, pipe_to_file);
-
-       /*
-        * If file or inode is SYNC and we actually wrote some data, sync it.
-        */
-       if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(mapping->host))
-           && ret > 0) {
+       if (ret > 0) {
                struct inode *inode = mapping->host;
-               int err;
 
-               mutex_lock(&inode->i_mutex);
-               err = generic_osync_inode(mapping->host, mapping,
-                                         OSYNC_METADATA|OSYNC_DATA);
-               mutex_unlock(&inode->i_mutex);
+               *ppos += ret;
+
+               /*
+                * If file or inode is SYNC and we actually wrote some data,
+                * sync it.
+                */
+               if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) {
+                       int err;
+
+                       mutex_lock(&inode->i_mutex);
+                       err = generic_osync_inode(inode, mapping,
+                                                 OSYNC_METADATA|OSYNC_DATA);
+                       mutex_unlock(&inode->i_mutex);
 
-               if (err)
-                       ret = err;
+                       if (err)
+                               ret = err;
+               }
        }
 
        return ret;
@@ -937,6 +941,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
 {
        struct pipe_inode_info *pipe;
        loff_t offset, *off;
+       long ret;
 
        pipe = in->f_dentry->d_inode->i_pipe;
        if (pipe) {
@@ -951,7 +956,12 @@ static long do_splice(struct file *in, loff_t __user *off_in,
                } else
                        off = &out->f_pos;
 
-               return do_splice_from(pipe, out, off, len, flags);
+               ret = do_splice_from(pipe, out, off, len, flags);
+
+               if (off_out && copy_to_user(off_out, off, sizeof(loff_t)))
+                       ret = -EFAULT;
+
+               return ret;
        }
 
        pipe = out->f_dentry->d_inode->i_pipe;
@@ -967,7 +977,12 @@ static long do_splice(struct file *in, loff_t __user *off_in,
                } else
                        off = &in->f_pos;
 
-               return do_splice_to(in, off, pipe, len, flags);
+               ret = do_splice_to(in, off, pipe, len, flags);
+
+               if (off_in && copy_to_user(off_in, off, sizeof(loff_t)))
+                       ret = -EFAULT;
+
+               return ret;
        }
 
        return -EINVAL;