diff options
| -rw-r--r-- | fs/iomap.c | 1053 | ||||
| -rw-r--r-- | fs/iomap/Makefile | 1 | ||||
| -rw-r--r-- | fs/iomap/buffered-io.c | 1073 |
3 files changed, 1074 insertions, 1053 deletions
diff --git a/fs/iomap.c b/fs/iomap.c index c983fedc7081..88a3144351a9 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -89,1056 +89,3 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, return written ? written : ret; } - -static struct iomap_page * -iomap_page_create(struct inode *inode, struct page *page) -{ - struct iomap_page *iop = to_iomap_page(page); - - if (iop || i_blocksize(inode) == PAGE_SIZE) - return iop; - - iop = kmalloc(sizeof(*iop), GFP_NOFS | __GFP_NOFAIL); - atomic_set(&iop->read_count, 0); - atomic_set(&iop->write_count, 0); - bitmap_zero(iop->uptodate, PAGE_SIZE / SECTOR_SIZE); - - /* - * migrate_page_move_mapping() assumes that pages with private data have - * their count elevated by 1. - */ - get_page(page); - set_page_private(page, (unsigned long)iop); - SetPagePrivate(page); - return iop; -} - -static void -iomap_page_release(struct page *page) -{ - struct iomap_page *iop = to_iomap_page(page); - - if (!iop) - return; - WARN_ON_ONCE(atomic_read(&iop->read_count)); - WARN_ON_ONCE(atomic_read(&iop->write_count)); - ClearPagePrivate(page); - set_page_private(page, 0); - put_page(page); - kfree(iop); -} - -/* - * Calculate the range inside the page that we actually need to read. - */ -static void -iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop, - loff_t *pos, loff_t length, unsigned *offp, unsigned *lenp) -{ - loff_t orig_pos = *pos; - loff_t isize = i_size_read(inode); - unsigned block_bits = inode->i_blkbits; - unsigned block_size = (1 << block_bits); - unsigned poff = offset_in_page(*pos); - unsigned plen = min_t(loff_t, PAGE_SIZE - poff, length); - unsigned first = poff >> block_bits; - unsigned last = (poff + plen - 1) >> block_bits; - - /* - * If the block size is smaller than the page size we need to check the - * per-block uptodate status and adjust the offset and length if needed - * to avoid reading in already uptodate ranges. - */ - if (iop) { - unsigned int i; - - /* move forward for each leading block marked uptodate */ - for (i = first; i <= last; i++) { - if (!test_bit(i, iop->uptodate)) - break; - *pos += block_size; - poff += block_size; - plen -= block_size; - first++; - } - - /* truncate len if we find any trailing uptodate block(s) */ - for ( ; i <= last; i++) { - if (test_bit(i, iop->uptodate)) { - plen -= (last - i + 1) * block_size; - last = i - 1; - break; - } - } - } - - /* - * If the extent spans the block that contains the i_size we need to - * handle both halves separately so that we properly zero data in the - * page cache for blocks that are entirely outside of i_size. - */ - if (orig_pos <= isize && orig_pos + length > isize) { - unsigned end = offset_in_page(isize - 1) >> block_bits; - - if (first <= end && last > end) - plen -= (last - end) * block_size; - } - - *offp = poff; - *lenp = plen; -} - -static void -iomap_set_range_uptodate(struct page *page, unsigned off, unsigned len) -{ - struct iomap_page *iop = to_iomap_page(page); - struct inode *inode = page->mapping->host; - unsigned first = off >> inode->i_blkbits; - unsigned last = (off + len - 1) >> inode->i_blkbits; - unsigned int i; - bool uptodate = true; - - if (iop) { - for (i = 0; i < PAGE_SIZE / i_blocksize(inode); i++) { - if (i >= first && i <= last) - set_bit(i, iop->uptodate); - else if (!test_bit(i, iop->uptodate)) - uptodate = false; - } - } - - if (uptodate && !PageError(page)) - SetPageUptodate(page); -} - -static void -iomap_read_finish(struct iomap_page *iop, struct page *page) -{ - if (!iop || atomic_dec_and_test(&iop->read_count)) - unlock_page(page); -} - -static void -iomap_read_page_end_io(struct bio_vec *bvec, int error) -{ - struct page *page = bvec->bv_page; - struct iomap_page *iop = to_iomap_page(page); - - if (unlikely(error)) { - ClearPageUptodate(page); - SetPageError(page); - } else { - iomap_set_range_uptodate(page, bvec->bv_offset, bvec->bv_len); - } - - iomap_read_finish(iop, page); -} - -static void -iomap_read_end_io(struct bio *bio) -{ - int error = blk_status_to_errno(bio->bi_status); - struct bio_vec *bvec; - struct bvec_iter_all iter_all; - - bio_for_each_segment_all(bvec, bio, iter_all) - iomap_read_page_end_io(bvec, error); - bio_put(bio); -} - -struct iomap_readpage_ctx { - struct page *cur_page; - bool cur_page_in_bio; - bool is_readahead; - struct bio *bio; - struct list_head *pages; -}; - -static void -iomap_read_inline_data(struct inode *inode, struct page *page, - struct iomap *iomap) -{ - size_t size = i_size_read(inode); - void *addr; - - if (PageUptodate(page)) - return; - - BUG_ON(page->index); - BUG_ON(size > PAGE_SIZE - offset_in_page(iomap->inline_data)); - - addr = kmap_atomic(page); - memcpy(addr, iomap->inline_data, size); - memset(addr + size, 0, PAGE_SIZE - size); - kunmap_atomic(addr); - SetPageUptodate(page); -} - -static loff_t -iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data, - struct iomap *iomap) -{ - struct iomap_readpage_ctx *ctx = data; - struct page *page = ctx->cur_page; - struct iomap_page *iop = iomap_page_create(inode, page); - bool same_page = false, is_contig = false; - loff_t orig_pos = pos; - unsigned poff, plen; - sector_t sector; - - if (iomap->type == IOMAP_INLINE) { - WARN_ON_ONCE(pos); - iomap_read_inline_data(inode, page, iomap); - return PAGE_SIZE; - } - - /* zero post-eof blocks as the page may be mapped */ - iomap_adjust_read_range(inode, iop, &pos, length, &poff, &plen); - if (plen == 0) - goto done; - - if (iomap->type != IOMAP_MAPPED || pos >= i_size_read(inode)) { - zero_user(page, poff, plen); - iomap_set_range_uptodate(page, poff, plen); - goto done; - } - - ctx->cur_page_in_bio = true; - - /* - * Try to merge into a previous segment if we can. - */ - sector = iomap_sector(iomap, pos); - if (ctx->bio && bio_end_sector(ctx->bio) == sector) - is_contig = true; - - if (is_contig && - __bio_try_merge_page(ctx->bio, page, plen, poff, &same_page)) { - if (!same_page && iop) - atomic_inc(&iop->read_count); - goto done; - } - - /* - * If we start a new segment we need to increase the read count, and we - * need to do so before submitting any previous full bio to make sure - * that we don't prematurely unlock the page. - */ - if (iop) - atomic_inc(&iop->read_count); - - if (!ctx->bio || !is_contig || bio_full(ctx->bio, plen)) { - gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL); - int nr_vecs = (length + PAGE_SIZE - 1) >> PAGE_SHIFT; - - if (ctx->bio) - submit_bio(ctx->bio); - - if (ctx->is_readahead) /* same as readahead_gfp_mask */ - gfp |= __GFP_NORETRY | __GFP_NOWARN; - ctx->bio = bio_alloc(gfp, min(BIO_MAX_PAGES, nr_vecs)); - ctx->bio->bi_opf = REQ_OP_READ; - if (ctx->is_readahead) - ctx->bio->bi_opf |= REQ_RAHEAD; - ctx->bio->bi_iter.bi_sector = sector; - bio_set_dev(ctx->bio, iomap->bdev); - ctx->bio->bi_end_io = iomap_read_end_io; - } - - bio_add_page(ctx->bio, page, plen, poff); -done: - /* - * Move the caller beyond our range so that it keeps making progress. - * For that we have to include any leading non-uptodate ranges, but - * we can skip trailing ones as they will be handled in the next - * iteration. - */ - return pos - orig_pos + plen; -} - -int -iomap_readpage(struct page *page, const struct iomap_ops *ops) -{ - struct iomap_readpage_ctx ctx = { .cur_page = page }; - struct inode *inode = page->mapping->host; - unsigned poff; - loff_t ret; - - for (poff = 0; poff < PAGE_SIZE; poff += ret) { - ret = iomap_apply(inode, page_offset(page) + poff, - PAGE_SIZE - poff, 0, ops, &ctx, - iomap_readpage_actor); - if (ret <= 0) { - WARN_ON_ONCE(ret == 0); - SetPageError(page); - break; - } - } - - if (ctx.bio) { - submit_bio(ctx.bio); - WARN_ON_ONCE(!ctx.cur_page_in_bio); - } else { - WARN_ON_ONCE(ctx.cur_page_in_bio); - unlock_page(page); - } - - /* - * Just like mpage_readpages and block_read_full_page we always - * return 0 and just mark the page as PageError on errors. This - * should be cleaned up all through the stack eventually. - */ - return 0; -} -EXPORT_SYMBOL_GPL(iomap_readpage); - -static struct page * -iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos, - loff_t length, loff_t *done) -{ - while (!list_empty(pages)) { - struct page *page = lru_to_page(pages); - - if (page_offset(page) >= (u64)pos + length) - break; - - list_del(&page->lru); - if (!add_to_page_cache_lru(page, inode->i_mapping, page->index, - GFP_NOFS)) - return page; - - /* - * If we already have a page in the page cache at index we are - * done. Upper layers don't care if it is uptodate after the - * readpages call itself as every page gets checked again once - * actually needed. - */ - *done += PAGE_SIZE; - put_page(page); - } - - return NULL; -} - -static loff_t -iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length, - void *data, struct iomap *iomap) -{ - struct iomap_readpage_ctx *ctx = data; - loff_t done, ret; - - for (done = 0; done < length; done += ret) { - if (ctx->cur_page && offset_in_page(pos + done) == 0) { - if (!ctx->cur_page_in_bio) - unlock_page(ctx->cur_page); - put_page(ctx->cur_page); - ctx->cur_page = NULL; - } - if (!ctx->cur_page) { - ctx->cur_page = iomap_next_page(inode, ctx->pages, - pos, length, &done); - if (!ctx->cur_page) - break; - ctx->cur_page_in_bio = false; - } - ret = iomap_readpage_actor(inode, pos + done, length - done, - ctx, iomap); - } - - return done; -} - -int -iomap_readpages(struct address_space *mapping, struct list_head *pages, - unsigned nr_pages, const struct iomap_ops *ops) -{ - struct iomap_readpage_ctx ctx = { - .pages = pages, - .is_readahead = true, - }; - loff_t pos = page_offset(list_entry(pages->prev, struct page, lru)); - loff_t last = page_offset(list_entry(pages->next, struct page, lru)); - loff_t length = last - pos + PAGE_SIZE, ret = 0; - - while (length > 0) { - ret = iomap_apply(mapping->host, pos, length, 0, ops, - &ctx, iomap_readpages_actor); - if (ret <= 0) { - WARN_ON_ONCE(ret == 0); - goto done; - } - pos += ret; - length -= ret; - } - ret = 0; -done: - if (ctx.bio) - submit_bio(ctx.bio); - if (ctx.cur_page) { - if (!ctx.cur_page_in_bio) - unlock_page(ctx.cur_page); - put_page(ctx.cur_page); - } - - /* - * Check that we didn't lose a page due to the arcance calling - * conventions.. - */ - WARN_ON_ONCE(!ret && !list_empty(ctx.pages)); - return ret; -} -EXPORT_SYMBOL_GPL(iomap_readpages); - -/* - * iomap_is_partially_uptodate checks whether blocks within a page are - * uptodate or not. - * - * Returns true if all blocks which correspond to a file portion - * we want to read within the page are uptodate. - */ -int -iomap_is_partially_uptodate(struct page *page, unsigned long from, - unsigned long count) -{ - struct iomap_page *iop = to_iomap_page(page); - struct inode *inode = page->mapping->host; - unsigned len, first, last; - unsigned i; - - /* Limit range to one page */ - len = min_t(unsigned, PAGE_SIZE - from, count); - - /* First and last blocks in range within page */ - first = from >> inode->i_blkbits; - last = (from + len - 1) >> inode->i_blkbits; - - if (iop) { - for (i = first; i <= last; i++) - if (!test_bit(i, iop->uptodate)) - return 0; - return 1; - } - - return 0; -} -EXPORT_SYMBOL_GPL(iomap_is_partially_uptodate); - -int -iomap_releasepage(struct page *page, gfp_t gfp_mask) -{ - /* - * mm accommodates an old ext3 case where clean pages might not have had - * the dirty bit cleared. Thus, it can send actual dirty pages to - * ->releasepage() via shrink_active_list(), skip those here. - */ - if (PageDirty(page) || PageWriteback(page)) - return 0; - iomap_page_release(page); - return 1; -} -EXPORT_SYMBOL_GPL(iomap_releasepage); - -void -iomap_invalidatepage(struct page *page, unsigned int offset, unsigned int len) -{ - /* - * If we are invalidating the entire page, clear the dirty state from it - * and release it to avoid unnecessary buildup of the LRU. - */ - if (offset == 0 && len == PAGE_SIZE) { - WARN_ON_ONCE(PageWriteback(page)); - cancel_dirty_page(page); - iomap_page_release(page); - } -} -EXPORT_SYMBOL_GPL(iomap_invalidatepage); - -#ifdef CONFIG_MIGRATION -int -iomap_migrate_page(struct address_space *mapping, struct page *newpage, - struct page *page, enum migrate_mode mode) -{ - int ret; - - ret = migrate_page_move_mapping(mapping, newpage, page, mode, 0); - if (ret != MIGRATEPAGE_SUCCESS) - return ret; - - if (page_has_private(page)) { - ClearPagePrivate(page); - get_page(newpage); - set_page_private(newpage, page_private(page)); - set_page_private(page, 0); - put_page(page); - SetPagePrivate(newpage); - } - - if (mode != MIGRATE_SYNC_NO_COPY) - migrate_page_copy(newpage, page); - else - migrate_page_states(newpage, page); - return MIGRATEPAGE_SUCCESS; -} -EXPORT_SYMBOL_GPL(iomap_migrate_page); -#endif /* CONFIG_MIGRATION */ - -static void -iomap_write_failed(struct inode *inode, loff_t pos, unsigned len) -{ - loff_t i_size = i_size_read(inode); - - /* - * Only truncate newly allocated pages beyoned EOF, even if the - * write started inside the existing inode size. - */ - if (pos + len > i_size) - truncate_pagecache_range(inode, max(pos, i_size), pos + len); -} - -static int -iomap_read_page_sync(struct inode *inode, loff_t block_start, struct page *page, - unsigned poff, unsigned plen, unsigned from, unsigned to, - struct iomap *iomap) -{ - struct bio_vec bvec; - struct bio bio; - - if (iomap->type != IOMAP_MAPPED || block_start >= i_size_read(inode)) { - zero_user_segments(page, poff, from, to, poff + plen); - iomap_set_range_uptodate(page, poff, plen); - return 0; - } - - bio_init(&bio, &bvec, 1); - bio.bi_opf = REQ_OP_READ; - bio.bi_iter.bi_sector = iomap_sector(iomap, block_start); - bio_set_dev(&bio, iomap->bdev); - __bio_add_page(&bio, page, plen, poff); - return submit_bio_wait(&bio); -} - -static int -__iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, - struct page *page, struct iomap *iomap) -{ - struct iomap_page *iop = iomap_page_create(inode, page); - loff_t block_size = i_blocksize(inode); - loff_t block_start = pos & ~(block_size - 1); - loff_t block_end = (pos + len + block_size - 1) & ~(block_size - 1); - unsigned from = offset_in_page(pos), to = from + len, poff, plen; - int status = 0; - - if (PageUptodate(page)) - return 0; - - do { - iomap_adjust_read_range(inode, iop, &block_start, - block_end - block_start, &poff, &plen); - if (plen == 0) - break; - - if ((from > poff && from < poff + plen) || - (to > poff && to < poff + plen)) { - status = iomap_read_page_sync(inode, block_start, page, - poff, plen, from, to, iomap); - if (status) - break; - } - - } while ((block_start += plen) < block_end); - - return status; -} - -static int -iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, - struct page **pagep, struct iomap *iomap) -{ - const struct iomap_page_ops *page_ops = iomap->page_ops; - pgoff_t index = pos >> PAGE_SHIFT; - struct page *page; - int status = 0; - - BUG_ON(pos + len > iomap->offset + iomap->length); - - if (fatal_signal_pending(current)) - return -EINTR; - - if (page_ops && page_ops->page_prepare) { - status = page_ops->page_prepare(inode, pos, len, iomap); - if (status) - return status; - } - - page = grab_cache_page_write_begin(inode->i_mapping, index, flags); - if (!page) { - status = -ENOMEM; - goto out_no_page; - } - - if (iomap->type == IOMAP_INLINE) - iomap_read_inline_data(inode, page, iomap); - else if (iomap->flags & IOMAP_F_BUFFER_HEAD) - status = __block_write_begin_int(page, pos, len, NULL, iomap); - else - status = __iomap_write_begin(inode, pos, len, page, iomap); - - if (unlikely(status)) - goto out_unlock; - - *pagep = page; - return 0; - -out_unlock: - unlock_page(page); - put_page(page); - iomap_write_failed(inode, pos, len); - -out_no_page: - if (page_ops && page_ops->page_done) - page_ops->page_done(inode, pos, 0, NULL, iomap); - return status; -} - -int -iomap_set_page_dirty(struct page *page) -{ - struct address_space *mapping = page_mapping(page); - int newly_dirty; - - if (unlikely(!mapping)) - return !TestSetPageDirty(page); - - /* - * Lock out page->mem_cgroup migration to keep PageDirty - * synchronized with per-memcg dirty page counters. - */ - lock_page_memcg(page); - newly_dirty = !TestSetPageDirty(page); - if (newly_dirty) - __set_page_dirty(page, mapping, 0); - unlock_page_memcg(page); - - if (newly_dirty) - __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); - return newly_dirty; -} -EXPORT_SYMBOL_GPL(iomap_set_page_dirty); - -static int -__iomap_write_end(struct inode *inode, loff_t pos, unsigned len, - unsigned copied, struct page *page, struct iomap *iomap) -{ - flush_dcache_page(page); - - /* - * The blocks that were entirely written will now be uptodate, so we - * don't have to worry about a readpage reading them and overwriting a - * partial write. However if we have encountered a short write and only - * partially written into a block, it will not be marked uptodate, so a - * readpage might come in and destroy our partial write. - * - * Do the simplest thing, and just treat any short write to a non - * uptodate page as a zero-length write, and force the caller to redo - * the whole thing. - */ - if (unlikely(copied < len && !PageUptodate(page))) - return 0; - iomap_set_range_uptodate(page, offset_in_page(pos), len); - iomap_set_page_dirty(page); - return copied; -} - -static int -iomap_write_end_inline(struct inode *inode, struct page *page, - struct iomap *iomap, loff_t pos, unsigned copied) -{ - void *addr; - - WARN_ON_ONCE(!PageUptodate(page)); - BUG_ON(pos + copied > PAGE_SIZE - offset_in_page(iomap->inline_data)); - - addr = kmap_atomic(page); - memcpy(iomap->inline_data + pos, addr + pos, copied); - kunmap_atomic(addr); - - mark_inode_dirty(inode); - return copied; -} - -static int -iomap_write_end(struct inode *inode, loff_t pos, unsigned len, - unsigned copied, struct page *page, struct iomap *iomap) -{ - const struct iomap_page_ops *page_ops = iomap->page_ops; - loff_t old_size = inode->i_size; - int ret; - - if (iomap->type == IOMAP_INLINE) { - ret = iomap_write_end_inline(inode, page, iomap, pos, copied); - } else if (iomap->flags & IOMAP_F_BUFFER_HEAD) { - ret = block_write_end(NULL, inode->i_mapping, pos, len, copied, - page, NULL); - } else { - ret = __iomap_write_end(inode, pos, len, copied, page, iomap); - } - - /* - * Update the in-memory inode size after copying the data into the page - * cache. It's up to the file system to write the updated size to disk, - * preferably after I/O completion so that no stale data is exposed. - */ - if (pos + ret > old_size) { - i_size_write(inode, pos + ret); - iomap->flags |= IOMAP_F_SIZE_CHANGED; - } - unlock_page(page); - - if (old_size < pos) - pagecache_isize_extended(inode, old_size, pos); - if (page_ops && page_ops->page_done) - page_ops->page_done(inode, pos, ret, page, iomap); - put_page(page); - - if (ret < len) - iomap_write_failed(inode, pos, len); - return ret; -} - -static loff_t -iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, - struct iomap *iomap) -{ - struct iov_iter *i = data; - long status = 0; - ssize_t written = 0; - unsigned int flags = AOP_FLAG_NOFS; - - do { - struct page *page; - unsigned long offset; /* Offset into pagecache page */ - unsigned long bytes; /* Bytes to write to page */ - size_t copied; /* Bytes copied from user */ - - offset = offset_in_page(pos); - bytes = min_t(unsigned long, PAGE_SIZE - offset, - iov_iter_count(i)); -again: - if (bytes > length) - bytes = length; - - /* - * Bring in the user page that we will copy from _first_. - * Otherwise there's a nasty deadlock on copying from the - * same page as we're writing to, without it being marked - * up-to-date. - * - * Not only is this an optimisation, but it is also required - * to check that the address is actually valid, when atomic - * usercopies are used, below. - */ - if (unlikely(iov_iter_fault_in_readable(i, bytes))) { - status = -EFAULT; - break; - } - - status = iomap_write_begin(inode, pos, bytes, flags, &page, - iomap); - if (unlikely(status)) - break; - - if (mapping_writably_mapped(inode->i_mapping)) - flush_dcache_page(page); - - copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes); - - flush_dcache_page(page); - - status = iomap_write_end(inode, pos, bytes, copied, page, - iomap); - if (unlikely(status < 0)) - break; - copied = status; - - cond_resched(); - - iov_iter_advance(i, copied); - if (unlikely(copied == 0)) { - /* - * If we were unable to copy any data at all, we must - * fall back to a single segment length write. - * - * If we didn't fallback here, we could livelock - * because not all segments in the iov can be copied at - * once without a pagefault. - */ - bytes = min_t(unsigned long, PAGE_SIZE - offset, - iov_iter_single_seg_count(i)); - goto again; - } - pos += copied; - written += copied; - length -= copied; - - balance_dirty_pages_ratelimited(inode->i_mapping); - } while (iov_iter_count(i) && length); - - return written ? written : status; -} - -ssize_t -iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *iter, - const struct iomap_ops *ops) -{ - struct inode *inode = iocb->ki_filp->f_mapping->host; - loff_t pos = iocb->ki_pos, ret = 0, written = 0; - - while (iov_iter_count(iter)) { - ret = iomap_apply(inode, pos, iov_iter_count(iter), - IOMAP_WRITE, ops, iter, iomap_write_actor); - if (ret <= 0) - break; - pos += ret; - written += ret; - } - - return written ? written : ret; -} -EXPORT_SYMBOL_GPL(iomap_file_buffered_write); - -static struct page * -__iomap_read_page(struct inode *inode, loff_t offset) -{ - struct address_space *mapping = inode->i_mapping; - struct page *page; - - page = read_mapping_page(mapping, offset >> PAGE_SHIFT, NULL); - if (IS_ERR(page)) - return page; - if (!PageUptodate(page)) { - put_page(page); - return ERR_PTR(-EIO); - } - return page; -} - -static loff_t -iomap_dirty_actor(struct inode *inode, loff_t pos, loff_t length, void *data, - struct iomap *iomap) -{ - long status = 0; - ssize_t written = 0; - - do { - struct page *page, *rpage; - unsigned long offset; /* Offset into pagecache page */ - unsigned long bytes; /* Bytes to write to page */ - - offset = offset_in_page(pos); - bytes = min_t(loff_t, PAGE_SIZE - offset, length); - - rpage = __iomap_read_page(inode, pos); - if (IS_ERR(rpage)) - return PTR_ERR(rpage); - - status = iomap_write_begin(inode, pos, bytes, - AOP_FLAG_NOFS, &page, iomap); - put_page(rpage); - if (unlikely(status)) - return status; - - WARN_ON_ONCE(!PageUptodate(page)); - - status = iomap_write_end(inode, pos, bytes, bytes, page, iomap); - if (unlikely(status <= 0)) { - if (WARN_ON_ONCE(status == 0)) - return -EIO; - return status; - } - - cond_resched(); - - pos += status; - written += status; - length -= status; - - balance_dirty_pages_ratelimited(inode->i_mapping); - } while (length); - - return written; -} - -int -iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len, - const struct iomap_ops *ops) -{ - loff_t ret; - - while (len) { - ret = iomap_apply(inode, pos, len, IOMAP_WRITE, ops, NULL, - iomap_dirty_actor); - if (ret <= 0) - return ret; - pos += ret; - len -= ret; - } - - return 0; -} -EXPORT_SYMBOL_GPL(iomap_file_dirty); - -static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset, - unsigned bytes, struct iomap *iomap) -{ - struct page *page; - int status; - - status = iomap_write_begin(inode, pos, bytes, AOP_FLAG_NOFS, &page, - iomap); - if (status) - return status; - - zero_user(page, offset, bytes); - mark_page_accessed(page); - - return iomap_write_end(inode, pos, bytes, bytes, page, iomap); -} - -static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes, - struct iomap *iomap) -{ - return __dax_zero_page_range(iomap->bdev, iomap->dax_dev, - iomap_sector(iomap, pos & PAGE_MASK), offset, bytes); -} - -static loff_t -iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count, - void *data, struct iomap *iomap) -{ - bool *did_zero = data; - loff_t written = 0; - int status; - - /* already zeroed? we're done. */ - if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) - return count; - - do { - unsigned offset, bytes; - - offset = offset_in_page(pos); - bytes = min_t(loff_t, PAGE_SIZE - offset, count); - - if (IS_DAX(inode)) - status = iomap_dax_zero(pos, offset, bytes, iomap); - else - status = iomap_zero(inode, pos, offset, bytes, iomap); - if (status < 0) - return status; - - pos += bytes; - count -= bytes; - written += bytes; - if (did_zero) - *did_zero = true; - } while (count > 0); - - return written; -} - -int -iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero, - const struct iomap_ops *ops) -{ - loff_t ret; - - while (len > 0) { - ret = iomap_apply(inode, pos, len, IOMAP_ZERO, - ops, did_zero, iomap_zero_range_actor); - if (ret <= 0) - return ret; - - pos += ret; - len -= ret; - } - - return 0; -} -EXPORT_SYMBOL_GPL(iomap_zero_range); - -int -iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, - const struct iomap_ops *ops) -{ - unsigned int blocksize = i_blocksize(inode); - unsigned int off = pos & (blocksize - 1); - - /* Block boundary? Nothing to do */ - if (!off) - return 0; - return iomap_zero_range(inode, pos, blocksize - off, did_zero, ops); -} -EXPORT_SYMBOL_GPL(iomap_truncate_page); - -static loff_t -iomap_page_mkwrite_actor(struct inode *inode, loff_t pos, loff_t length, - void *data, struct iomap *iomap) -{ - struct page *page = data; - int ret; - - if (iomap->flags & IOMAP_F_BUFFER_HEAD) { - ret = __block_write_begin_int(page, pos, length, NULL, iomap); - if (ret) - return ret; - block_commit_write(page, 0, length); - } else { - WARN_ON_ONCE(!PageUptodate(page)); - iomap_page_create(inode, page); - set_page_dirty(page); - } - - return length; -} - -vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops) -{ - struct page *page = vmf->page; - struct inode *inode = file_inode(vmf->vma->vm_file); - unsigned long length; - loff_t offset, size; - ssize_t ret; - - lock_page(page); - size = i_size_read(inode); - if ((page->mapping != inode->i_mapping) || - (page_offset(page) > size)) { - /* We overload EFAULT to mean page got truncated */ - ret = -EFAULT; - goto out_unlock; - } - - /* page is wholly or partially inside EOF */ - if (((page->index + 1) << PAGE_SHIFT) > size) - length = offset_in_page(size); - else - length = PAGE_SIZE; - - offset = page_offset(page); - while (length > 0) { - ret = iomap_apply(inode, offset, length, - IOMAP_WRITE | IOMAP_FAULT, ops, page, - iomap_page_mkwrite_actor); - if (unlikely(ret <= 0)) - goto out_unlock; - offset += ret; - length -= ret; - } - - wait_for_stable_page(page); - return VM_FAULT_LOCKED; -out_unlock: - unlock_page(page); - return block_page_mkwrite_return(ret); -} -EXPORT_SYMBOL_GPL(iomap_page_mkwrite); diff --git a/fs/iomap/Makefile b/fs/iomap/Makefile index a67a97758858..19fd672cd486 100644 --- a/fs/iomap/Makefile +++ b/fs/iomap/Makefile @@ -6,6 +6,7 @@ obj-$(CONFIG_FS_IOMAP) += iomap.o iomap-y += \ + buffered-io.o \ direct-io.o \ fiemap.o \ seek.o diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c new file mode 100644 index 000000000000..da4d958f9dc8 --- /dev/null +++ b/fs/iomap/buffered-io.c @@ -0,0 +1,1073 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2010 Red Hat, Inc. + * Copyright (c) 2016-2018 Christoph Hellwig. + */ +#include <linux/module.h> +#include <linux/compiler.h> +#include <linux/fs.h> +#include <linux/iomap.h> +#include <linux/pagemap.h> +#include <linux/uio.h> +#include <linux/buffer_head.h> +#include <linux/dax.h> +#include <linux/writeback.h> +#include <linux/swap.h> +#include <linux/bio.h> +#include <linux/sched/signal.h> +#include <linux/migrate.h> + +#include "../internal.h" + +static struct iomap_page * +iomap_page_create(struct inode *inode, struct page *page) +{ + struct iomap_page *iop = to_iomap_page(page); + + if (iop || i_blocksize(inode) == PAGE_SIZE) + return iop; + + iop = kmalloc(sizeof(*iop), GFP_NOFS | __GFP_NOFAIL); + atomic_set(&iop->read_count, 0); + atomic_set(&iop->write_count, 0); + bitmap_zero(iop->uptodate, PAGE_SIZE / SECTOR_SIZE); + + /* + * migrate_page_move_mapping() assumes that pages with private data have + * their count elevated by 1. + */ + get_page(page); + set_page_private(page, (unsigned long)iop); + SetPagePrivate(page); + return iop; +} + +static void +iomap_page_release(struct page *page) +{ + struct iomap_page *iop = to_iomap_page(page); + + if (!iop) + return; + WARN_ON_ONCE(atomic_read(&iop->read_count)); + WARN_ON_ONCE(atomic_read(&iop->write_count)); + ClearPagePrivate(page); + set_page_private(page, 0); + put_page(page); + kfree(iop); +} + +/* + * Calculate the range inside the page that we actually need to read. + */ +static void +iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop, + loff_t *pos, loff_t length, unsigned *offp, unsigned *lenp) +{ + loff_t orig_pos = *pos; + loff_t isize = i_size_read(inode); + unsigned block_bits = inode->i_blkbits; + unsigned block_size = (1 << block_bits); + unsigned poff = offset_in_page(*pos); + unsigned plen = min_t(loff_t, PAGE_SIZE - poff, length); + unsigned first = poff >> block_bits; + unsigned last = (poff + plen - 1) >> block_bits; + + /* + * If the block size is smaller than the page size we need to check the + * per-block uptodate status and adjust the offset and length if needed + * to avoid reading in already uptodate ranges. + */ + if (iop) { + unsigned int i; + + /* move forward for each leading block marked uptodate */ + for (i = first; i <= last; i++) { + if (!test_bit(i, iop->uptodate)) + break; + *pos += block_size; + poff += block_size; + plen -= block_size; + first++; + } + + /* truncate len if we find any trailing uptodate block(s) */ + for ( ; i <= last; i++) { + if (test_bit(i, iop->uptodate)) { + plen -= (last - i + 1) * block_size; + last = i - 1; + break; + } + } + } + + /* + * If the extent spans the block that contains the i_size we need to + * handle both halves separately so that we properly zero data in the + * page cache for blocks that are entirely outside of i_size. + */ + if (orig_pos <= isize && orig_pos + length > isize) { + unsigned end = offset_in_page(isize - 1) >> block_bits; + + if (first <= end && last > end) + plen -= (last - end) * block_size; + } + + *offp = poff; + *lenp = plen; +} + +static void +iomap_set_range_uptodate(struct page *page, unsigned off, unsigned len) +{ + struct iomap_page *iop = to_iomap_page(page); + struct inode *inode = page->mapping->host; + unsigned first = off >> inode->i_blkbits; + unsigned last = (off + len - 1) >> inode->i_blkbits; + unsigned int i; + bool uptodate = true; + + if (iop) { + for (i = 0; i < PAGE_SIZE / i_blocksize(inode); i++) { + if (i >= first && i <= last) + set_bit(i, iop->uptodate); + else if (!test_bit(i, iop->uptodate)) + uptodate = false; + } + } + + if (uptodate && !PageError(page)) + SetPageUptodate(page); +} + +static void +iomap_read_finish(struct iomap_page *iop, struct page *page) +{ + if (!iop || atomic_dec_and_test(&iop->read_count)) + unlock_page(page); +} + +static void +iomap_read_page_end_io(struct bio_vec *bvec, int error) +{ + struct page *page = bvec->bv_page; + struct iomap_page *iop = to_iomap_page(page); + + if (unlikely(error)) { + ClearPageUptodate(page); + SetPageError(page); + } else { + iomap_set_range_uptodate(page, bvec->bv_offset, bvec->bv_len); + } + + iomap_read_finish(iop, page); +} + +static void +iomap_read_end_io(struct bio *bio) +{ + int error = blk_status_to_errno(bio->bi_status); + struct bio_vec *bvec; + struct bvec_iter_all iter_all; + + bio_for_each_segment_all(bvec, bio, iter_all) + iomap_read_page_end_io(bvec, error); + bio_put(bio); +} + +struct iomap_readpage_ctx { + struct page *cur_page; + bool cur_page_in_bio; + bool is_readahead; + struct bio *bio; + struct list_head *pages; +}; + +static void +iomap_read_inline_data(struct inode *inode, struct page *page, + struct iomap *iomap) +{ + size_t size = i_size_read(inode); + void *addr; + + if (PageUptodate(page)) + return; + + BUG_ON(page->index); + BUG_ON(size > PAGE_SIZE - offset_in_page(iomap->inline_data)); + + addr = kmap_atomic(page); + memcpy(addr, iomap->inline_data, size); + memset(addr + size, 0, PAGE_SIZE - size); + kunmap_atomic(addr); + SetPageUptodate(page); +} + +static loff_t +iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data, + struct iomap *iomap) +{ + struct iomap_readpage_ctx *ctx = data; + struct page *page = ctx->cur_page; + struct iomap_page *iop = iomap_page_create(inode, page); + bool same_page = false, is_contig = false; + loff_t orig_pos = pos; + unsigned poff, plen; + sector_t sector; + + if (iomap->type == IOMAP_INLINE) { + WARN_ON_ONCE(pos); + iomap_read_inline_data(inode, page, iomap); + return PAGE_SIZE; + } + + /* zero post-eof blocks as the page may be mapped */ + iomap_adjust_read_range(inode, iop, &pos, length, &poff, &plen); + if (plen == 0) + goto done; + + if (iomap->type != IOMAP_MAPPED || pos >= i_size_read(inode)) { + zero_user(page, poff, plen); + iomap_set_range_uptodate(page, poff, plen); + goto done; + } + + ctx->cur_page_in_bio = true; + + /* + * Try to merge into a previous segment if we can. + */ + sector = iomap_sector(iomap, pos); + if (ctx->bio && bio_end_sector(ctx->bio) == sector) + is_contig = true; + + if (is_contig && + __bio_try_merge_page(ctx->bio, page, plen, poff, &same_page)) { + if (!same_page && iop) + atomic_inc(&iop->read_count); + goto done; + } + + /* + * If we start a new segment we need to increase the read count, and we + * need to do so before submitting any previous full bio to make sure + * that we don't prematurely unlock the page. + */ + if (iop) + atomic_inc(&iop->read_count); + + if (!ctx->bio || !is_contig || bio_full(ctx->bio, plen)) { + gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL); + int nr_vecs = (length + PAGE_SIZE - 1) >> PAGE_SHIFT; + + if (ctx->bio) + submit_bio(ctx->bio); + + if (ctx->is_readahead) /* same as readahead_gfp_mask */ + gfp |= __GFP_NORETRY | __GFP_NOWARN; + ctx->bio = bio_alloc(gfp, min(BIO_MAX_PAGES, nr_vecs)); + ctx->bio->bi_opf = REQ_OP_READ; + if (ctx->is_readahead) + ctx->bio->bi_opf |= REQ_RAHEAD; + ctx->bio->bi_iter.bi_sector = sector; + bio_set_dev(ctx->bio, iomap->bdev); + ctx->bio->bi_end_io = iomap_read_end_io; + } + + bio_add_page(ctx->bio, page, plen, poff); +done: + /* + * Move the caller beyond our range so that it keeps making progress. + * For that we have to include any leading non-uptodate ranges, but + * we can skip trailing ones as they will be handled in the next + * iteration. + */ + return pos - orig_pos + plen; +} + +int +iomap_readpage(struct page *page, const struct iomap_ops *ops) +{ + struct iomap_readpage_ctx ctx = { .cur_page = page }; + struct inode *inode = page->mapping->host; + unsigned poff; + loff_t ret; + + for (poff = 0; poff < PAGE_SIZE; poff += ret) { + ret = iomap_apply(inode, page_offset(page) + poff, + PAGE_SIZE - poff, 0, ops, &ctx, + iomap_readpage_actor); + if (ret <= 0) { + WARN_ON_ONCE(ret == 0); + SetPageError(page); + break; + } + } + + if (ctx.bio) { + submit_bio(ctx.bio); + WARN_ON_ONCE(!ctx.cur_page_in_bio); + } else { + WARN_ON_ONCE(ctx.cur_page_in_bio); + unlock_page(page); + } + + /* + * Just like mpage_readpages and block_read_full_page we always + * return 0 and just mark the page as PageError on errors. This + * should be cleaned up all through the stack eventually. + */ + return 0; +} +EXPORT_SYMBOL_GPL(iomap_readpage); + +static struct page * +iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos, + loff_t length, loff_t *done) +{ + while (!list_empty(pages)) { + struct page *page = lru_to_page(pages); + + if (page_offset(page) >= (u64)pos + length) + break; + + list_del(&page->lru); + if (!add_to_page_cache_lru(page, inode->i_mapping, page->index, + GFP_NOFS)) + return page; + + /* + * If we already have a page in the page cache at index we are + * done. Upper layers don't care if it is uptodate after the + * readpages call itself as every page gets checked again once + * actually needed. + */ + *done += PAGE_SIZE; + put_page(page); + } + + return NULL; +} + +static loff_t +iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length, + void *data, struct iomap *iomap) +{ + struct iomap_readpage_ctx *ctx = data; + loff_t done, ret; + + for (done = 0; done < length; done += ret) { + if (ctx->cur_page && offset_in_page(pos + done) == 0) { + if (!ctx->cur_page_in_bio) + unlock_page(ctx->cur_page); + put_page(ctx->cur_page); + ctx->cur_page = NULL; + } + if (!ctx->cur_page) { + ctx->cur_page = iomap_next_page(inode, ctx->pages, + pos, length, &done); + if (!ctx->cur_page) + break; + ctx->cur_page_in_bio = false; + } + ret = iomap_readpage_actor(inode, pos + done, length - done, + ctx, iomap); + } + + return done; +} + +int +iomap_readpages(struct address_space *mapping, struct list_head *pages, + unsigned nr_pages, const struct iomap_ops *ops) +{ + struct iomap_readpage_ctx ctx = { + .pages = pages, + .is_readahead = true, + }; + loff_t pos = page_offset(list_entry(pages->prev, struct page, lru)); + loff_t last = page_offset(list_entry(pages->next, struct page, lru)); + loff_t length = last - pos + PAGE_SIZE, ret = 0; + + while (length > 0) { + ret = iomap_apply(mapping->host, pos, length, 0, ops, + &ctx, iomap_readpages_actor); + if (ret <= 0) { + WARN_ON_ONCE(ret == 0); + goto done; + } + pos += ret; + length -= ret; + } + ret = 0; +done: + if (ctx.bio) + submit_bio(ctx.bio); + if (ctx.cur_page) { + if (!ctx.cur_page_in_bio) + unlock_page(ctx.cur_page); + put_page(ctx.cur_page); + } + + /* + * Check that we didn't lose a page due to the arcance calling + * conventions.. + */ + WARN_ON_ONCE(!ret && !list_empty(ctx.pages)); + return ret; +} +EXPORT_SYMBOL_GPL(iomap_readpages); + +/* + * iomap_is_partially_uptodate checks whether blocks within a page are + * uptodate or not. + * + * Returns true if all blocks which correspond to a file portion + * we want to read within the page are uptodate. + */ +int +iomap_is_partially_uptodate(struct page *page, unsigned long from, + unsigned long count) +{ + struct iomap_page *iop = to_iomap_page(page); + struct inode *inode = page->mapping->host; + unsigned len, first, last; + unsigned i; + + /* Limit range to one page */ + len = min_t(unsigned, PAGE_SIZE - from, count); + + /* First and last blocks in range within page */ + first = from >> inode->i_blkbits; + last = (from + len - 1) >> inode->i_blkbits; + + if (iop) { + for (i = first; i <= last; i++) + if (!test_bit(i, iop->uptodate)) + return 0; + return 1; + } + + return 0; +} +EXPORT_SYMBOL_GPL(iomap_is_partially_uptodate); + +int +iomap_releasepage(struct page *page, gfp_t gfp_mask) +{ + /* + * mm accommodates an old ext3 case where clean pages might not have had + * the dirty bit cleared. Thus, it can send actual dirty pages to + * ->releasepage() via shrink_active_list(), skip those here. + */ + if (PageDirty(page) || PageWriteback(page)) + return 0; + iomap_page_release(page); + return 1; +} +EXPORT_SYMBOL_GPL(iomap_releasepage); + +void +iomap_invalidatepage(struct page *page, unsigned int offset, unsigned int len) +{ + /* + * If we are invalidating the entire page, clear the dirty state from it + * and release it to avoid unnecessary buildup of the LRU. + */ + if (offset == 0 && len == PAGE_SIZE) { + WARN_ON_ONCE(PageWriteback(page)); + cancel_dirty_page(page); + iomap_page_release(page); + } +} +EXPORT_SYMBOL_GPL(iomap_invalidatepage); + +#ifdef CONFIG_MIGRATION +int +iomap_migrate_page(struct address_space *mapping, struct page *newpage, + struct page *page, enum migrate_mode mode) +{ + int ret; + + ret = migrate_page_move_mapping(mapping, newpage, page, mode, 0); + if (ret != MIGRATEPAGE_SUCCESS) + return ret; + + if (page_has_private(page)) { + ClearPagePrivate(page); + get_page(newpage); + set_page_private(newpage, page_private(page)); + set_page_private(page, 0); + put_page(page); + SetPagePrivate(newpage); + } + + if (mode != MIGRATE_SYNC_NO_COPY) + migrate_page_copy(newpage, page); + else + migrate_page_states(newpage, page); + return MIGRATEPAGE_SUCCESS; +} +EXPORT_SYMBOL_GPL(iomap_migrate_page); +#endif /* CONFIG_MIGRATION */ + +static void +iomap_write_failed(struct inode *inode, loff_t pos, unsigned len) +{ + loff_t i_size = i_size_read(inode); + + /* + * Only truncate newly allocated pages beyoned EOF, even if the + * write started inside the existing inode size. + */ + if (pos + len > i_size) + truncate_pagecache_range(inode, max(pos, i_size), pos + len); +} + +static int +iomap_read_page_sync(struct inode *inode, loff_t block_start, struct page *page, + unsigned poff, unsigned plen, unsigned from, unsigned to, + struct iomap *iomap) +{ + struct bio_vec bvec; + struct bio bio; + + if (iomap->type != IOMAP_MAPPED || block_start >= i_size_read(inode)) { + zero_user_segments(page, poff, from, to, poff + plen); + iomap_set_range_uptodate(page, poff, plen); + return 0; + } + + bio_init(&bio, &bvec, 1); + bio.bi_opf = REQ_OP_READ; + bio.bi_iter.bi_sector = iomap_sector(iomap, block_start); + bio_set_dev(&bio, iomap->bdev); + __bio_add_page(&bio, page, plen, poff); + return submit_bio_wait(&bio); +} + +static int +__iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, + struct page *page, struct iomap *iomap) +{ + struct iomap_page *iop = iomap_page_create(inode, page); + loff_t block_size = i_blocksize(inode); + loff_t block_start = pos & ~(block_size - 1); + loff_t block_end = (pos + len + block_size - 1) & ~(block_size - 1); + unsigned from = offset_in_page(pos), to = from + len, poff, plen; + int status = 0; + + if (PageUptodate(page)) + return 0; + + do { + iomap_adjust_read_range(inode, iop, &block_start, + block_end - block_start, &poff, &plen); + if (plen == 0) + break; + + if ((from > poff && from < poff + plen) || + (to > poff && to < poff + plen)) { + status = iomap_read_page_sync(inode, block_start, page, + poff, plen, from, to, iomap); + if (status) + break; + } + + } while ((block_start += plen) < block_end); + + return status; +} + +static int +iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, + struct page **pagep, struct iomap *iomap) +{ + const struct iomap_page_ops *page_ops = iomap->page_ops; + pgoff_t index = pos >> PAGE_SHIFT; + struct page *page; + int status = 0; + + BUG_ON(pos + len > iomap->offset + iomap->length); + + if (fatal_signal_pending(current)) + return -EINTR; + + if (page_ops && page_ops->page_prepare) { + status = page_ops->page_prepare(inode, pos, len, iomap); + if (status) + return status; + } + + page = grab_cache_page_write_begin(inode->i_mapping, index, flags); + if (!page) { + status = -ENOMEM; + goto out_no_page; + } + + if (iomap->type == IOMAP_INLINE) + iomap_read_inline_data(inode, page, iomap); + else if (iomap->flags & IOMAP_F_BUFFER_HEAD) + status = __block_write_begin_int(page, pos, len, NULL, iomap); + else + status = __iomap_write_begin(inode, pos, len, page, iomap); + + if (unlikely(status)) + goto out_unlock; + + *pagep = page; + return 0; + +out_unlock: + unlock_page(page); + put_page(page); + iomap_write_failed(inode, pos, len); + +out_no_page: + if (page_ops && page_ops->page_done) + page_ops->page_done(inode, pos, 0, NULL, iomap); + return status; +} + +int +iomap_set_page_dirty(struct page *page) +{ + struct address_space *mapping = page_mapping(page); + int newly_dirty; + + if (unlikely(!mapping)) + return !TestSetPageDirty(page); + + /* + * Lock out page->mem_cgroup migration to keep PageDirty + * synchronized with per-memcg dirty page counters. + */ + lock_page_memcg(page); + newly_dirty = !TestSetPageDirty(page); + if (newly_dirty) + __set_page_dirty(page, mapping, 0); + unlock_page_memcg(page); + + if (newly_dirty) + __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); + return newly_dirty; +} +EXPORT_SYMBOL_GPL(iomap_set_page_dirty); + +static int +__iomap_write_end(struct inode *inode, loff_t pos, unsigned len, + unsigned copied, struct page *page, struct iomap *iomap) +{ + flush_dcache_page(page); + + /* + * The blocks that were entirely written will now be uptodate, so we + * don't have to worry about a readpage reading them and overwriting a + * partial write. However if we have encountered a short write and only + * partially written into a block, it will not be marked uptodate, so a + * readpage might come in and destroy our partial write. + * + * Do the simplest thing, and just treat any short write to a non + * uptodate page as a zero-length write, and force the caller to redo + * the whole thing. + */ + if (unlikely(copied < len && !PageUptodate(page))) + return 0; + iomap_set_range_uptodate(page, offset_in_page(pos), len); + iomap_set_page_dirty(page); + return copied; +} + +static int +iomap_write_end_inline(struct inode *inode, struct page *page, + struct iomap *iomap, loff_t pos, unsigned copied) +{ + void *addr; + + WARN_ON_ONCE(!PageUptodate(page)); + BUG_ON(pos + copied > PAGE_SIZE - offset_in_page(iomap->inline_data)); + + addr = kmap_atomic(page); + memcpy(iomap->inline_data + pos, addr + pos, copied); + kunmap_atomic(addr); + + mark_inode_dirty(inode); + return copied; +} + +static int +iomap_write_end(struct inode *inode, loff_t pos, unsigned len, + unsigned copied, struct page *page, struct iomap *iomap) +{ + const struct iomap_page_ops *page_ops = iomap->page_ops; + loff_t old_size = inode->i_size; + int ret; + + if (iomap->type == IOMAP_INLINE) { + ret = iomap_write_end_inline(inode, page, iomap, pos, copied); + } else if (iomap->flags & IOMAP_F_BUFFER_HEAD) { + ret = block_write_end(NULL, inode->i_mapping, pos, len, copied, + page, NULL); + } else { + ret = __iomap_write_end(inode, pos, len, copied, page, iomap); + } + + /* + * Update the in-memory inode size after copying the data into the page + * cache. It's up to the file system to write the updated size to disk, + * preferably after I/O completion so that no stale data is exposed. + */ + if (pos + ret > old_size) { + i_size_write(inode, pos + ret); + iomap->flags |= IOMAP_F_SIZE_CHANGED; + } + unlock_page(page); + + if (old_size < pos) + pagecache_isize_extended(inode, old_size, pos); + if (page_ops && page_ops->page_done) + page_ops->page_done(inode, pos, ret, page, iomap); + put_page(page); + + if (ret < len) + iomap_write_failed(inode, pos, len); + return ret; +} + +static loff_t +iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, + struct iomap *iomap) +{ + struct iov_iter *i = data; + long status = 0; + ssize_t written = 0; + unsigned int flags = AOP_FLAG_NOFS; + + do { + struct page *page; + unsigned long offset; /* Offset into pagecache page */ + unsigned long bytes; /* Bytes to write to page */ + size_t copied; /* Bytes copied from user */ + + offset = offset_in_page(pos); + bytes = min_t(unsigned long, PAGE_SIZE - offset, + iov_iter_count(i)); +again: + if (bytes > length) + bytes = length; + + /* + * Bring in the user page that we will copy from _first_. + * Otherwise there's a nasty deadlock on copying from the + * same page as we're writing to, without it being marked + * up-to-date. + * + * Not only is this an optimisation, but it is also required + * to check that the address is actually valid, when atomic + * usercopies are used, below. + */ + if (unlikely(iov_iter_fault_in_readable(i, bytes))) { + status = -EFAULT; + break; + } + + status = iomap_write_begin(inode, pos, bytes, flags, &page, + iomap); + if (unlikely(status)) + break; + + if (mapping_writably_mapped(inode->i_mapping)) + flush_dcache_page(page); + + copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes); + + flush_dcache_page(page); + + status = iomap_write_end(inode, pos, bytes, copied, page, + iomap); + if (unlikely(status < 0)) + break; + copied = status; + + cond_resched(); + + iov_iter_advance(i, copied); + if (unlikely(copied == 0)) { + /* + * If we were unable to copy any data at all, we must + * fall back to a single segment length write. + * + * If we didn't fallback here, we could livelock + * because not all segments in the iov can be copied at + * once without a pagefault. + */ + bytes = min_t(unsigned long, PAGE_SIZE - offset, + iov_iter_single_seg_count(i)); + goto again; + } + pos += copied; + written += copied; + length -= copied; + + balance_dirty_pages_ratelimited(inode->i_mapping); + } while (iov_iter_count(i) && length); + + return written ? written : status; +} + +ssize_t +iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *iter, + const struct iomap_ops *ops) +{ + struct inode *inode = iocb->ki_filp->f_mapping->host; + loff_t pos = iocb->ki_pos, ret = 0, written = 0; + + while (iov_iter_count(iter)) { + ret = iomap_apply(inode, pos, iov_iter_count(iter), + IOMAP_WRITE, ops, iter, iomap_write_actor); + if (ret <= 0) + break; + pos += ret; + written += ret; + } + + return written ? written : ret; +} +EXPORT_SYMBOL_GPL(iomap_file_buffered_write); + +static struct page * +__iomap_read_page(struct inode *inode, loff_t offset) +{ + struct address_space *mapping = inode->i_mapping; + struct page *page; + + page = read_mapping_page(mapping, offset >> PAGE_SHIFT, NULL); + if (IS_ERR(page)) + return page; + if (!PageUptodate(page)) { + put_page(page); + return ERR_PTR(-EIO); + } + return page; +} + +static loff_t +iomap_dirty_actor(struct inode *inode, loff_t pos, loff_t length, void *data, + struct iomap *iomap) +{ + long status = 0; + ssize_t written = 0; + + do { + struct page *page, *rpage; + unsigned long offset; /* Offset into pagecache page */ + unsigned long bytes; /* Bytes to write to page */ + + offset = offset_in_page(pos); + bytes = min_t(loff_t, PAGE_SIZE - offset, length); + + rpage = __iomap_read_page(inode, pos); + if (IS_ERR(rpage)) + return PTR_ERR(rpage); + + status = iomap_write_begin(inode, pos, bytes, + AOP_FLAG_NOFS, &page, iomap); + put_page(rpage); + if (unlikely(status)) + return status; + + WARN_ON_ONCE(!PageUptodate(page)); + + status = iomap_write_end(inode, pos, bytes, bytes, page, iomap); + if (unlikely(status <= 0)) { + if (WARN_ON_ONCE(status == 0)) + return -EIO; + return status; + } + + cond_resched(); + + pos += status; + written += status; + length -= status; + + balance_dirty_pages_ratelimited(inode->i_mapping); + } while (length); + + return written; +} + +int +iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len, + const struct iomap_ops *ops) +{ + loff_t ret; + + while (len) { + ret = iomap_apply(inode, pos, len, IOMAP_WRITE, ops, NULL, + iomap_dirty_actor); + if (ret <= 0) + return ret; + pos += ret; + len -= ret; + } + + return 0; +} +EXPORT_SYMBOL_GPL(iomap_file_dirty); + +static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset, + unsigned bytes, struct iomap *iomap) +{ + struct page *page; + int status; + + status = iomap_write_begin(inode, pos, bytes, AOP_FLAG_NOFS, &page, + iomap); + if (status) + return status; + + zero_user(page, offset, bytes); + mark_page_accessed(page); + + return iomap_write_end(inode, pos, bytes, bytes, page, iomap); +} + +static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes, + struct iomap *iomap) +{ + return __dax_zero_page_range(iomap->bdev, iomap->dax_dev, + iomap_sector(iomap, pos & PAGE_MASK), offset, bytes); +} + +static loff_t +iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count, + void *data, struct iomap *iomap) +{ + bool *did_zero = data; + loff_t written = 0; + int status; + + /* already zeroed? we're done. */ + if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) + return count; + + do { + unsigned offset, bytes; + + offset = offset_in_page(pos); + bytes = min_t(loff_t, PAGE_SIZE - offset, count); + + if (IS_DAX(inode)) + status = iomap_dax_zero(pos, offset, bytes, iomap); + else + status = iomap_zero(inode, pos, offset, bytes, iomap); + if (status < 0) + return status; + + pos += bytes; + count -= bytes; + written += bytes; + if (did_zero) + *did_zero = true; + } while (count > 0); + + return written; +} + +int +iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero, + const struct iomap_ops *ops) +{ + loff_t ret; + + while (len > 0) { + ret = iomap_apply(inode, pos, len, IOMAP_ZERO, + ops, did_zero, iomap_zero_range_actor); + if (ret <= 0) + return ret; + + pos += ret; + len -= ret; + } + + return 0; +} +EXPORT_SYMBOL_GPL(iomap_zero_range); + +int +iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, + const struct iomap_ops *ops) +{ + unsigned int blocksize = i_blocksize(inode); + unsigned int off = pos & (blocksize - 1); + + /* Block boundary? Nothing to do */ + if (!off) + return 0; + return iomap_zero_range(inode, pos, blocksize - off, did_zero, ops); +} +EXPORT_SYMBOL_GPL(iomap_truncate_page); + +static loff_t +iomap_page_mkwrite_actor(struct inode *inode, loff_t pos, loff_t length, + void *data, struct iomap *iomap) +{ + struct page *page = data; + int ret; + + if (iomap->flags & IOMAP_F_BUFFER_HEAD) { + ret = __block_write_begin_int(page, pos, length, NULL, iomap); + if (ret) + return ret; + block_commit_write(page, 0, length); + } else { + WARN_ON_ONCE(!PageUptodate(page)); + iomap_page_create(inode, page); + set_page_dirty(page); + } + + return length; +} + +vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops) +{ + struct page *page = vmf->page; + struct inode *inode = file_inode(vmf->vma->vm_file); + unsigned long length; + loff_t offset, size; + ssize_t ret; + + lock_page(page); + size = i_size_read(inode); + if ((page->mapping != inode->i_mapping) || + (page_offset(page) > size)) { + /* We overload EFAULT to mean page got truncated */ + ret = -EFAULT; + goto out_unlock; + } + + /* page is wholly or partially inside EOF */ + if (((page->index + 1) << PAGE_SHIFT) > size) + length = offset_in_page(size); + else + length = PAGE_SIZE; + + offset = page_offset(page); + while (length > 0) { + ret = iomap_apply(inode, offset, length, + IOMAP_WRITE | IOMAP_FAULT, ops, page, + iomap_page_mkwrite_actor); + if (unlikely(ret <= 0)) + goto out_unlock; + offset += ret; + length -= ret; + } + + wait_for_stable_page(page); + return VM_FAULT_LOCKED; +out_unlock: + unlock_page(page); + return block_page_mkwrite_return(ret); +} +EXPORT_SYMBOL_GPL(iomap_page_mkwrite); |