Messages in this thread Patch in this message | | | Subject | [PATCH 3/3] mm: Provide stub page_mkwrite functionality to stabilize pages during writes | From | "Darrick J. Wong" <> | Date | Thu, 19 May 2011 15:49:03 -0700 |
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For filesystems that do not provide any page_mkwrite handler, provide a stub page_mkwrite function that locks the page and waits for pending writeback to complete. This is needed to stabilize pages during writes for a large variety of filesystem drivers (ext2, ext3, vfat, hfs...).
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com> --- mm/filemap.c | 19 +++++++++++++++++++ 1 files changed, 19 insertions(+), 0 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c index fd0e7f2..2a922b4 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1713,8 +1713,27 @@ page_not_uptodate: } EXPORT_SYMBOL(filemap_fault); +static int stub_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + struct page *page = vmf->page; + struct inode *inode = vma->vm_file->f_path.dentry->d_inode; + loff_t size; + + lock_page(page); + size = i_size_read(inode); + if ((page->mapping != inode->i_mapping) || + (page_offset(page) > size)) { + /* page got truncated out from underneath us */ + unlock_page(page); + return VM_FAULT_NOPAGE; + } + wait_on_page_writeback(page); + return VM_FAULT_LOCKED; +} + const struct vm_operations_struct generic_file_vm_ops = { .fault = filemap_fault, + .page_mkwrite = stub_page_mkwrite, }; /* This is used for a general mmap of a disk file */
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