xfs: fallocate() should call file_modified()

commit fbe7e520036583a783b13ff9744e35c2a329d9a4 upsream.

In XFS, we always update the inode change and modification time when
any fallocate() operation succeeds.  Furthermore, as various
fallocate modes can change the file contents (extending EOF,
punching holes, zeroing things, shifting extents), we should drop
file privileges like suid just like we do for a regular write().
There's already a VFS helper that figures all this out for us, so
use that.

The net effect of this is that we no longer drop suid/sgid if the
caller is root, but we also now drop file capabilities.

We also move the xfs_update_prealloc_flags() function so that it now
is only called by the scope that needs to set the the prealloc flag.

Based on a patch from Darrick Wong.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Tested-by: Leah Rumancik <leah.rumancik@gmail.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 752b676c92e3ffa047f9c35992b7e55e76f14e2a..020e0a412287a7a3353f4ee8617d9513fa4fd0ae 100644 (file)
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -954,6 +954,10 @@ xfs_file_fallocate(
                        goto out_unlock;
        }
 
+       error = file_modified(file);
+       if (error)
+               goto out_unlock;
+
        if (mode & FALLOC_FL_PUNCH_HOLE) {
                error = xfs_free_file_space(ip, offset, len);
                if (error)
@@ -1055,11 +1059,12 @@ xfs_file_fallocate(
                        if (error)
                                goto out_unlock;
                }
-       }
 
-       error = xfs_update_prealloc_flags(ip, flags);
-       if (error)
-               goto out_unlock;
+               error = xfs_update_prealloc_flags(ip, XFS_PREALLOC_SET);
+               if (error)
+                       goto out_unlock;
+
+       }
 
        /* Change file size if needed */
        if (new_size) {