diff options
Diffstat (limited to 'fs/dax.c')
| -rw-r--r-- | fs/dax.c | 52 |
1 files changed, 42 insertions, 10 deletions
@@ -155,7 +155,7 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter, } if (iov_iter_rw(iter) == WRITE) - len = copy_from_iter(addr, max - pos, iter); + len = copy_from_iter_nocache(addr, max - pos, iter); else if (!hole) len = copy_to_iter(addr, max - pos, iter); else @@ -209,7 +209,8 @@ ssize_t dax_do_io(struct kiocb *iocb, struct inode *inode, } /* Protects against truncate */ - inode_dio_begin(inode); + if (!(flags & DIO_SKIP_DIO_COUNT)) + inode_dio_begin(inode); retval = dax_io(inode, iter, pos, end, get_block, &bh); @@ -219,7 +220,8 @@ ssize_t dax_do_io(struct kiocb *iocb, struct inode *inode, if ((retval > 0) && end_io) end_io(iocb, pos, retval, bh.b_private); - inode_dio_end(inode); + if (!(flags & DIO_SKIP_DIO_COUNT)) + inode_dio_end(inode); out: return retval; } @@ -309,14 +311,27 @@ 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 + * @complete_unwritten: The filesystem method used to convert unwritten blocks + * to written so the data written to them is exposed. This is required for + * required by write faults for filesystems that will return unwritten + * extent mappings from @get_block, but it is optional for reads as + * dax_insert_mapping() will always zero unwritten blocks. If the fs does + * not support unwritten extents, the it should pass NULL. + * + * 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 +432,23 @@ 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)) { + if (complete_unwritten) + complete_unwritten(&bh, !error); + else + WARN_ON_ONCE(!(vmf->flags & FAULT_FLAG_WRITE)); + } out: if (error == -ENOMEM) @@ -434,6 +465,7 @@ 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 +477,7 @@ 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 +486,7 @@ 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); |