On Mon, Mar 27, 2023 at 06:45:13PM +0100, Matthew Wilcox (Oracle) wrote:
> XFS doesn't actually need to be holding the XFS_MMAPLOCK_SHARED to do
> this. filemap_map_pages() cannot bring new folios into the page cache
> and the folio lock is taken during filemap_map_pages() which provides
> sufficient protection against a truncation or hole punch.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> ---
> fs/xfs/xfs_file.c | 17 +----------------
> 1 file changed, 1 insertion(+), 16 deletions(-)
>
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 863289aaa441..aede746541f8 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -1389,25 +1389,10 @@ xfs_filemap_pfn_mkwrite(
> return __xfs_filemap_fault(vmf, PE_SIZE_PTE, true);
> }
>
> -static vm_fault_t
> -xfs_filemap_map_pages(
> - struct vm_fault *vmf,
> - pgoff_t start_pgoff,
> - pgoff_t end_pgoff)
> -{
> - struct inode *inode = file_inode(vmf->vma->vm_file);
> - vm_fault_t ret;
> -
> - xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
> - ret = filemap_map_pages(vmf, start_pgoff, end_pgoff);
> - xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
> - return ret;
> -}
> -
> static const struct vm_operations_struct xfs_file_vm_ops = {
> .fault = xfs_filemap_fault,
> .huge_fault = xfs_filemap_huge_fault,
> - .map_pages = xfs_filemap_map_pages,
> + .map_pages = filemap_map_pages,
> .page_mkwrite = xfs_filemap_page_mkwrite,
> .pfn_mkwrite = xfs_filemap_pfn_mkwrite,
> };
> --
> 2.39.2
Looks fine.
Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx>
--
Dave Chinner
david@xxxxxxxxxxxxx
