diff options
Diffstat (limited to 'fs/dax.c')
| -rw-r--r-- | fs/dax.c | 34 |
1 files changed, 27 insertions, 7 deletions
@@ -309,14 +309,21 @@ static int dax_insert_mapping(struct inode *inode, struct buffer_head *bh, out: i_mmap_unlock_read(mapping); - if (bh->b_end_io) - bh->b_end_io(bh, 1); - return error; } -static int do_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, - get_block_t get_block) +/** + * __dax_fault - handle a page fault on a DAX file + * @vma: The virtual memory area where the fault occurred + * @vmf: The description of the fault + * @get_block: The filesystem method used to translate file offsets to blocks + * + * When a page fault occurs, filesystems may call this helper in their + * fault handler for DAX files. __dax_fault() assumes the caller has done all + * the necessary locking for the page fault to proceed successfully. + */ +int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, + get_block_t get_block, dax_iodone_t complete_unwritten) { struct file *file = vma->vm_file; struct address_space *mapping = file->f_mapping; @@ -417,7 +424,19 @@ static int do_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, page_cache_release(page); } + /* + * If we successfully insert the new mapping over an unwritten extent, + * we need to ensure we convert the unwritten extent. If there is an + * error inserting the mapping, the filesystem needs to leave it as + * unwritten to prevent exposure of the stale underlying data to + * userspace, but we still need to call the completion function so + * the private resources on the mapping buffer can be released. We + * indicate what the callback should do via the uptodate variable, same + * as for normal BH based IO completions. + */ error = dax_insert_mapping(inode, &bh, vma, vmf); + if (buffer_unwritten(&bh)) + complete_unwritten(&bh, !error); out: if (error == -ENOMEM) @@ -434,6 +453,7 @@ static int do_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, } goto out; } +EXPORT_SYMBOL(__dax_fault); /** * dax_fault - handle a page fault on a DAX file @@ -445,7 +465,7 @@ static int do_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, * fault handler for DAX files. */ int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, - get_block_t get_block) + get_block_t get_block, dax_iodone_t complete_unwritten) { int result; struct super_block *sb = file_inode(vma->vm_file)->i_sb; @@ -454,7 +474,7 @@ int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, sb_start_pagefault(sb); file_update_time(vma->vm_file); } - result = do_dax_fault(vma, vmf, get_block); + result = __dax_fault(vma, vmf, get_block, complete_unwritten); if (vmf->flags & FAULT_FLAG_WRITE) sb_end_pagefault(sb); |