diff options
Diffstat (limited to 'mm/filemap.c')
| -rw-r--r-- | mm/filemap.c | 87 |
1 files changed, 52 insertions, 35 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 151090fdcf29..66f7e9fdfbc4 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -142,17 +142,6 @@ static void page_cache_delete(struct address_space *mapping, page->mapping = NULL; /* Leave page->index set: truncation lookup relies upon it */ - - if (shadow) { - mapping->nrexceptional += nr; - /* - * Make sure the nrexceptional update is committed before - * the nrpages update so that final truncate racing - * with reclaim does not see both counters 0 at the - * same time and miss a shadow entry. - */ - smp_wmb(); - } mapping->nrpages -= nr; } @@ -629,13 +618,53 @@ EXPORT_SYMBOL(filemap_fdatawait_keep_errors); /* Returns true if writeback might be needed or already in progress. */ static bool mapping_needs_writeback(struct address_space *mapping) { - if (dax_mapping(mapping)) - return mapping->nrexceptional; - return mapping->nrpages; } /** + * filemap_range_needs_writeback - check if range potentially needs writeback + * @mapping: address space within which to check + * @start_byte: offset in bytes where the range starts + * @end_byte: offset in bytes where the range ends (inclusive) + * + * Find at least one page in the range supplied, usually used to check if + * direct writing in this range will trigger a writeback. Used by O_DIRECT + * read/write with IOCB_NOWAIT, to see if the caller needs to do + * filemap_write_and_wait_range() before proceeding. + * + * Return: %true if the caller should do filemap_write_and_wait_range() before + * doing O_DIRECT to a page in this range, %false otherwise. + */ +bool filemap_range_needs_writeback(struct address_space *mapping, + loff_t start_byte, loff_t end_byte) +{ + XA_STATE(xas, &mapping->i_pages, start_byte >> PAGE_SHIFT); + pgoff_t max = end_byte >> PAGE_SHIFT; + struct page *page; + + if (!mapping_needs_writeback(mapping)) + return false; + if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) && + !mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK)) + return false; + if (end_byte < start_byte) + return false; + + rcu_read_lock(); + xas_for_each(&xas, page, max) { + if (xas_retry(&xas, page)) + continue; + if (xa_is_value(page)) + continue; + if (PageDirty(page) || PageLocked(page) || PageWriteback(page)) + break; + } + rcu_read_unlock(); + return page != NULL; +} +EXPORT_SYMBOL_GPL(filemap_range_needs_writeback); + +/** * filemap_write_and_wait_range - write out & wait on a file range * @mapping: the address_space for the pages * @lstart: offset in bytes where the range starts @@ -882,8 +911,6 @@ noinline int __add_to_page_cache_locked(struct page *page, if (xas_error(&xas)) goto unlock; - if (old) - mapping->nrexceptional--; mapping->nrpages++; /* hugetlb pages do not participate in page cache accounting */ @@ -1724,7 +1751,7 @@ EXPORT_SYMBOL(page_cache_prev_miss); * @mapping: the address_space to search * @index: The page cache index. * - * Looks up the page cache slot at @mapping & @offset. If there is a + * Looks up the page cache slot at @mapping & @index. If there is a * page cache page, the head page is returned with an increased refcount. * * If the slot holds a shadow entry of a previously evicted page, or a @@ -2305,8 +2332,6 @@ static int filemap_read_page(struct file *file, struct address_space *mapping, return error; if (PageUptodate(page)) return 0; - if (!page->mapping) /* page truncated */ - return AOP_TRUNCATED_PAGE; shrink_readahead_size_eio(&file->f_ra); return -EIO; } @@ -2638,8 +2663,8 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) size = i_size_read(inode); if (iocb->ki_flags & IOCB_NOWAIT) { - if (filemap_range_has_page(mapping, iocb->ki_pos, - iocb->ki_pos + count - 1)) + if (filemap_range_needs_writeback(mapping, iocb->ki_pos, + iocb->ki_pos + count - 1)) return -EAGAIN; } else { retval = filemap_write_and_wait_range(mapping, @@ -2730,7 +2755,7 @@ unsigned int seek_page_size(struct xa_state *xas, struct page *page) * entirely memory-based such as tmpfs, and filesystems which support * unwritten extents. * - * Return: The requested offset on successs, or -ENXIO if @whence specifies + * Return: The requested offset on success, or -ENXIO if @whence specifies * SEEK_DATA and there is no data after @start. There is an implicit hole * after @end - 1, so SEEK_HOLE returns @end if all the bytes between @start * and @end contain data. @@ -2937,7 +2962,6 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) struct file *file = vmf->vma->vm_file; struct file *fpin = NULL; struct address_space *mapping = file->f_mapping; - struct file_ra_state *ra = &file->f_ra; struct inode *inode = mapping->host; pgoff_t offset = vmf->pgoff; pgoff_t max_off; @@ -3024,14 +3048,8 @@ page_not_uptodate: * because there really aren't any performance issues here * and we need to check for errors. */ - ClearPageError(page); fpin = maybe_unlock_mmap_for_io(vmf, fpin); - error = mapping->a_ops->readpage(file, page); - if (!error) { - wait_on_page_locked(page); - if (!PageUptodate(page)) - error = -EIO; - } + error = filemap_read_page(file, mapping, page); if (fpin) goto out_retry; put_page(page); @@ -3039,7 +3057,6 @@ page_not_uptodate: if (!error || error == AOP_TRUNCATED_PAGE) goto retry_find; - shrink_readahead_size_eio(ra); return VM_FAULT_SIGBUS; out_retry: @@ -3250,7 +3267,7 @@ const struct vm_operations_struct generic_file_vm_ops = { /* This is used for a general mmap of a disk file */ -int generic_file_mmap(struct file * file, struct vm_area_struct * vma) +int generic_file_mmap(struct file *file, struct vm_area_struct *vma) { struct address_space *mapping = file->f_mapping; @@ -3275,11 +3292,11 @@ vm_fault_t filemap_page_mkwrite(struct vm_fault *vmf) { return VM_FAULT_SIGBUS; } -int generic_file_mmap(struct file * file, struct vm_area_struct * vma) +int generic_file_mmap(struct file *file, struct vm_area_struct *vma) { return -ENOSYS; } -int generic_file_readonly_mmap(struct file * file, struct vm_area_struct * vma) +int generic_file_readonly_mmap(struct file *file, struct vm_area_struct *vma) { return -ENOSYS; } @@ -3707,7 +3724,7 @@ EXPORT_SYMBOL(generic_perform_write); ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from) { struct file *file = iocb->ki_filp; - struct address_space * mapping = file->f_mapping; + struct address_space *mapping = file->f_mapping; struct inode *inode = mapping->host; ssize_t written = 0; ssize_t err; |