xfs: mmap lock needs to be inside freeze protection
Lock ordering for the new mmap lock needs to be:
mmap_sem
sb_start_pagefault
i_mmap_lock
page lock
<fault processsing>
Right now xfs_vm_page_mkwrite gets this the wrong way around,
While technically it cannot deadlock due to the current freeze
ordering, it's still a landmine that might explode if we change
anything in future. Hence we need to nest the locks correctly.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 8121e75..0b4e79f 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1487,15 +1487,20 @@
struct vm_fault *vmf)
{
struct xfs_inode *ip = XFS_I(vma->vm_file->f_mapping->host);
- int error;
+ int ret;
trace_xfs_filemap_page_mkwrite(ip);
+ sb_start_pagefault(VFS_I(ip)->i_sb);
+ file_update_time(vma->vm_file);
xfs_ilock(ip, XFS_MMAPLOCK_SHARED);
- error = block_page_mkwrite(vma, vmf, xfs_get_blocks);
- xfs_iunlock(ip, XFS_MMAPLOCK_SHARED);
- return error;
+ ret = __block_page_mkwrite(vma, vmf, xfs_get_blocks);
+
+ xfs_iunlock(ip, XFS_MMAPLOCK_SHARED);
+ sb_end_pagefault(VFS_I(ip)->i_sb);
+
+ return block_page_mkwrite_return(ret);
}
const struct file_operations xfs_file_operations = {