vfs: remap helper should update destination inode metadata

Extend generic_remap_file_range_prep to handle inode metadata updates
when remapping into a file.  If the operation can possibly alter the
file contents, we must update the ctime and mtime and remove security
privileges, just like we do for regular file writes.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/fs/read_write.c b/fs/read_write.c
index ebcbfc4..b61bd3f 100644 (file)
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1820,6 +1820,25 @@ int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,
        if (ret)
                return ret;
 
+       /* If can't alter the file contents, we're done. */
+       if (!(remap_flags & REMAP_FILE_DEDUP)) {
+               /* Update the timestamps, since we can alter file contents. */
+               if (!(file_out->f_mode & FMODE_NOCMTIME)) {
+                       ret = file_update_time(file_out);
+                       if (ret)
+                               return ret;
+               }
+
+               /*
+                * Clear the security bits if the process is not being run by
+                * root.  This keeps people from modifying setuid and setgid
+                * binaries.
+                */
+               ret = file_remove_privs(file_out);
+               if (ret)
+                       return ret;
+       }
+
        return 1;
 }
 EXPORT_SYMBOL(generic_remap_file_range_prep);

diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 29aab19..2d7dd8b 100644 (file)
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -1372,29 +1372,6 @@ xfs_reflink_remap_prep(
        truncate_inode_pages_range(&inode_out->i_data, pos_out,
                                   PAGE_ALIGN(pos_out + *len) - 1);
 
-       /* If we're altering the file contents... */
-       if (!(remap_flags & REMAP_FILE_DEDUP)) {
-               /*
-                * ...update the timestamps (which will grab the ilock again
-                * from xfs_fs_dirty_inode, so we have to call it before we
-                * take the ilock).
-                */
-               if (!(file_out->f_mode & FMODE_NOCMTIME)) {
-                       ret = file_update_time(file_out);
-                       if (ret)
-                               goto out_unlock;
-               }
-
-               /*
-                * ...clear the security bits if the process is not being run
-                * by root.  This keeps people from modifying setuid and setgid
-                * binaries.
-                */
-               ret = file_remove_privs(file_out);
-               if (ret)
-                       goto out_unlock;
-       }
-
        return 1;
 out_unlock:
        xfs_reflink_remap_unlock(file_in, file_out);