[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>

1 files changed, 30 insertions, 15 deletions

diff --git a/fs/splice.c b/fs/splice.c
index 4f5e6b09fb26..27d6408ff490 100644
--- 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;