From 13ad4fe3e087ab66a140f1e00d98f28aa4e3bb28 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Tue, 3 Nov 2015 12:37:02 +1100 Subject: [PATCH] xfs: xfs_filemap_pmd_fault treats read faults as write faults The code initially committed didn't have the same checks for write faults as the dax_pmd_fault code and hence treats all faults as write faults. We can get read faults through this path because they is no pmd_mkwrite path for write faults similar to the normal page fault path. Hence we need to ensure that we only do c/mtime updates on write faults, and freeze protection is unnecessary for read faults. Signed-off-by: Dave Chinner Reviewed-by: Brian Foster Signed-off-by: Dave Chinner --- fs/xfs/xfs_file.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index f429662d7d42..ce208e3896aa 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1477,7 +1477,7 @@ xfs_file_llseek( * * mmap_sem (MM) * sb_start_pagefault(vfs, freeze) - * i_mmap_lock (XFS - truncate serialisation) + * i_mmaplock (XFS - truncate serialisation) * page_lock (MM) * i_lock (XFS - extent map serialisation) */ @@ -1545,6 +1545,13 @@ xfs_filemap_fault( return ret; } +/* + * Similar to xfs_filemap_fault(), the DAX fault path can call into here on + * both read and write faults. Hence we need to handle both cases. There is no + * ->pmd_mkwrite callout for huge pages, so we have a single function here to + * handle both cases here. @flags carries the information on the type of fault + * occuring. + */ STATIC int xfs_filemap_pmd_fault( struct vm_area_struct *vma, @@ -1561,13 +1568,18 @@ xfs_filemap_pmd_fault( trace_xfs_filemap_pmd_fault(ip); - sb_start_pagefault(inode->i_sb); - file_update_time(vma->vm_file); + if (flags & FAULT_FLAG_WRITE) { + sb_start_pagefault(inode->i_sb); + file_update_time(vma->vm_file); + } + xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED); ret = __dax_pmd_fault(vma, addr, pmd, flags, xfs_get_blocks_dax_fault, NULL); xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED); - sb_end_pagefault(inode->i_sb); + + if (flags & FAULT_FLAG_WRITE) + sb_end_pagefault(inode->i_sb); return ret; } -- 2.20.1