| /* |
| * fs/mpage.c |
| * |
| * Copyright (C) 2002, Linus Torvalds. |
| * |
| * Contains functions related to preparing and submitting BIOs which contain |
| * multiple pagecache pages. |
| * |
| * 15May2002 akpm@zip.com.au |
| * Initial version |
| * 27Jun2002 axboe@suse.de |
| * use bio_add_page() to build bio's just the right size |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/mm.h> |
| #include <linux/kdev_t.h> |
| #include <linux/bio.h> |
| #include <linux/fs.h> |
| #include <linux/buffer_head.h> |
| #include <linux/blkdev.h> |
| #include <linux/highmem.h> |
| #include <linux/prefetch.h> |
| #include <linux/mpage.h> |
| #include <linux/writeback.h> |
| #include <linux/backing-dev.h> |
| #include <linux/pagevec.h> |
| |
| /* |
| * I/O completion handler for multipage BIOs. |
| * |
| * The mpage code never puts partial pages into a BIO (except for end-of-file). |
| * If a page does not map to a contiguous run of blocks then it simply falls |
| * back to block_read_full_page(). |
| * |
| * Why is this? If a page's completion depends on a number of different BIOs |
| * which can complete in any order (or at the same time) then determining the |
| * status of that page is hard. See end_buffer_async_read() for the details. |
| * There is no point in duplicating all that complexity. |
| */ |
| static int mpage_end_io_read(struct bio *bio, unsigned int bytes_done, int err) |
| { |
| const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); |
| struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1; |
| |
| if (bio->bi_size) |
| return 1; |
| |
| do { |
| struct page *page = bvec->bv_page; |
| |
| if (--bvec >= bio->bi_io_vec) |
| prefetchw(&bvec->bv_page->flags); |
| |
| if (uptodate) { |
| SetPageUptodate(page); |
| } else { |
| ClearPageUptodate(page); |
| SetPageError(page); |
| } |
| unlock_page(page); |
| } while (bvec >= bio->bi_io_vec); |
| bio_put(bio); |
| return 0; |
| } |
| |
| static int mpage_end_io_write(struct bio *bio, unsigned int bytes_done, int err) |
| { |
| const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); |
| struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1; |
| |
| if (bio->bi_size) |
| return 1; |
| |
| do { |
| struct page *page = bvec->bv_page; |
| |
| if (--bvec >= bio->bi_io_vec) |
| prefetchw(&bvec->bv_page->flags); |
| |
| if (!uptodate){ |
| SetPageError(page); |
| if (page->mapping) |
| set_bit(AS_EIO, &page->mapping->flags); |
| } |
| end_page_writeback(page); |
| } while (bvec >= bio->bi_io_vec); |
| bio_put(bio); |
| return 0; |
| } |
| |
| static struct bio *mpage_bio_submit(int rw, struct bio *bio) |
| { |
| bio->bi_end_io = mpage_end_io_read; |
| if (rw == WRITE) |
| bio->bi_end_io = mpage_end_io_write; |
| submit_bio(rw, bio); |
| return NULL; |
| } |
| |
| static struct bio * |
| mpage_alloc(struct block_device *bdev, |
| sector_t first_sector, int nr_vecs, |
| gfp_t gfp_flags) |
| { |
| struct bio *bio; |
| |
| bio = bio_alloc(gfp_flags, nr_vecs); |
| |
| if (bio == NULL && (current->flags & PF_MEMALLOC)) { |
| while (!bio && (nr_vecs /= 2)) |
| bio = bio_alloc(gfp_flags, nr_vecs); |
| } |
| |
| if (bio) { |
| bio->bi_bdev = bdev; |
| bio->bi_sector = first_sector; |
| } |
| return bio; |
| } |
| |
| /* |
| * support function for mpage_readpages. The fs supplied get_block might |
| * return an up to date buffer. This is used to map that buffer into |
| * the page, which allows readpage to avoid triggering a duplicate call |
| * to get_block. |
| * |
| * The idea is to avoid adding buffers to pages that don't already have |
| * them. So when the buffer is up to date and the page size == block size, |
| * this marks the page up to date instead of adding new buffers. |
| */ |
| static void |
| map_buffer_to_page(struct page *page, struct buffer_head *bh, int page_block) |
| { |
| struct inode *inode = page->mapping->host; |
| struct buffer_head *page_bh, *head; |
| int block = 0; |
| |
| if (!page_has_buffers(page)) { |
| /* |
| * don't make any buffers if there is only one buffer on |
| * the page and the page just needs to be set up to date |
| */ |
| if (inode->i_blkbits == PAGE_CACHE_SHIFT && |
| buffer_uptodate(bh)) { |
| SetPageUptodate(page); |
| return; |
| } |
| create_empty_buffers(page, 1 << inode->i_blkbits, 0); |
| } |
| head = page_buffers(page); |
| page_bh = head; |
| do { |
| if (block == page_block) { |
| page_bh->b_state = bh->b_state; |
| page_bh->b_bdev = bh->b_bdev; |
| page_bh->b_blocknr = bh->b_blocknr; |
| break; |
| } |
| page_bh = page_bh->b_this_page; |
| block++; |
| } while (page_bh != head); |
| } |
| |
| static struct bio * |
| do_mpage_readpage(struct bio *bio, struct page *page, unsigned nr_pages, |
| sector_t *last_block_in_bio, get_block_t get_block) |
| { |
| struct inode *inode = page->mapping->host; |
| const unsigned blkbits = inode->i_blkbits; |
| const unsigned blocks_per_page = PAGE_CACHE_SIZE >> blkbits; |
| const unsigned blocksize = 1 << blkbits; |
| sector_t block_in_file; |
| sector_t last_block; |
| sector_t blocks[MAX_BUF_PER_PAGE]; |
| unsigned page_block; |
| unsigned first_hole = blocks_per_page; |
| struct block_device *bdev = NULL; |
| struct buffer_head bh; |
| int length; |
| int fully_mapped = 1; |
| |
| if (page_has_buffers(page)) |
| goto confused; |
| |
| block_in_file = page->index << (PAGE_CACHE_SHIFT - blkbits); |
| last_block = (i_size_read(inode) + blocksize - 1) >> blkbits; |
| |
| bh.b_page = page; |
| for (page_block = 0; page_block < blocks_per_page; |
| page_block++, block_in_file++) { |
| bh.b_state = 0; |
| if (block_in_file < last_block) { |
| if (get_block(inode, block_in_file, &bh, 0)) |
| goto confused; |
| } |
| |
| if (!buffer_mapped(&bh)) { |
| fully_mapped = 0; |
| if (first_hole == blocks_per_page) |
| first_hole = page_block; |
| continue; |
| } |
| |
| /* some filesystems will copy data into the page during |
| * the get_block call, in which case we don't want to |
| * read it again. map_buffer_to_page copies the data |
| * we just collected from get_block into the page's buffers |
| * so readpage doesn't have to repeat the get_block call |
| */ |
| if (buffer_uptodate(&bh)) { |
| map_buffer_to_page(page, &bh, page_block); |
| goto confused; |
| } |
| |
| if (first_hole != blocks_per_page) |
| goto confused; /* hole -> non-hole */ |
| |
| /* Contiguous blocks? */ |
| if (page_block && blocks[page_block-1] != bh.b_blocknr-1) |
| goto confused; |
| blocks[page_block] = bh.b_blocknr; |
| bdev = bh.b_bdev; |
| } |
| |
| if (first_hole != blocks_per_page) { |
| char *kaddr = kmap_atomic(page, KM_USER0); |
| memset(kaddr + (first_hole << blkbits), 0, |
| PAGE_CACHE_SIZE - (first_hole << blkbits)); |
| flush_dcache_page(page); |
| kunmap_atomic(kaddr, KM_USER0); |
| if (first_hole == 0) { |
| SetPageUptodate(page); |
| unlock_page(page); |
| goto out; |
| } |
| } else if (fully_mapped) { |
| SetPageMappedToDisk(page); |
| } |
| |
| /* |
| * This page will go to BIO. Do we need to send this BIO off first? |
| */ |
| if (bio && (*last_block_in_bio != blocks[0] - 1)) |
| bio = mpage_bio_submit(READ, bio); |
| |
| alloc_new: |
| if (bio == NULL) { |
| bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9), |
| min_t(int, nr_pages, bio_get_nr_vecs(bdev)), |
| GFP_KERNEL); |
| if (bio == NULL) |
| goto confused; |
| } |
| |
| length = first_hole << blkbits; |
| if (bio_add_page(bio, page, length, 0) < length) { |
| bio = mpage_bio_submit(READ, bio); |
| goto alloc_new; |
| } |
| |
| if (buffer_boundary(&bh) || (first_hole != blocks_per_page)) |
| bio = mpage_bio_submit(READ, bio); |
| else |
| *last_block_in_bio = blocks[blocks_per_page - 1]; |
| out: |
| return bio; |
| |
| confused: |
| if (bio) |
| bio = mpage_bio_submit(READ, bio); |
| if (!PageUptodate(page)) |
| block_read_full_page(page, get_block); |
| else |
| unlock_page(page); |
| goto out; |
| } |
| |
| /** |
| * mpage_readpages - populate an address space with some pages, and |
| * start reads against them. |
| * |
| * @mapping: the address_space |
| * @pages: The address of a list_head which contains the target pages. These |
| * pages have their ->index populated and are otherwise uninitialised. |
| * |
| * The page at @pages->prev has the lowest file offset, and reads should be |
| * issued in @pages->prev to @pages->next order. |
| * |
| * @nr_pages: The number of pages at *@pages |
| * @get_block: The filesystem's block mapper function. |
| * |
| * This function walks the pages and the blocks within each page, building and |
| * emitting large BIOs. |
| * |
| * If anything unusual happens, such as: |
| * |
| * - encountering a page which has buffers |
| * - encountering a page which has a non-hole after a hole |
| * - encountering a page with non-contiguous blocks |
| * |
| * then this code just gives up and calls the buffer_head-based read function. |
| * It does handle a page which has holes at the end - that is a common case: |
| * the end-of-file on blocksize < PAGE_CACHE_SIZE setups. |
| * |
| * BH_Boundary explanation: |
| * |
| * There is a problem. The mpage read code assembles several pages, gets all |
| * their disk mappings, and then submits them all. That's fine, but obtaining |
| * the disk mappings may require I/O. Reads of indirect blocks, for example. |
| * |
| * So an mpage read of the first 16 blocks of an ext2 file will cause I/O to be |
| * submitted in the following order: |
| * 12 0 1 2 3 4 5 6 7 8 9 10 11 13 14 15 16 |
| * because the indirect block has to be read to get the mappings of blocks |
| * 13,14,15,16. Obviously, this impacts performance. |
| * |
| * So what we do it to allow the filesystem's get_block() function to set |
| * BH_Boundary when it maps block 11. BH_Boundary says: mapping of the block |
| * after this one will require I/O against a block which is probably close to |
| * this one. So you should push what I/O you have currently accumulated. |
| * |
| * This all causes the disk requests to be issued in the correct order. |
| */ |
| int |
| mpage_readpages(struct address_space *mapping, struct list_head *pages, |
| unsigned nr_pages, get_block_t get_block) |
| { |
| struct bio *bio = NULL; |
| unsigned page_idx; |
| sector_t last_block_in_bio = 0; |
| struct pagevec lru_pvec; |
| |
| pagevec_init(&lru_pvec, 0); |
| for (page_idx = 0; page_idx < nr_pages; page_idx++) { |
| struct page *page = list_entry(pages->prev, struct page, lru); |
| |
| prefetchw(&page->flags); |
| list_del(&page->lru); |
| if (!add_to_page_cache(page, mapping, |
| page->index, GFP_KERNEL)) { |
| bio = do_mpage_readpage(bio, page, |
| nr_pages - page_idx, |
| &last_block_in_bio, get_block); |
| if (!pagevec_add(&lru_pvec, page)) |
| __pagevec_lru_add(&lru_pvec); |
| } else { |
| page_cache_release(page); |
| } |
| } |
| pagevec_lru_add(&lru_pvec); |
| BUG_ON(!list_empty(pages)); |
| if (bio) |
| mpage_bio_submit(READ, bio); |
| return 0; |
| } |
| EXPORT_SYMBOL(mpage_readpages); |
| |
| /* |
| * This isn't called much at all |
| */ |
| int mpage_readpage(struct page *page, get_block_t get_block) |
| { |
| struct bio *bio = NULL; |
| sector_t last_block_in_bio = 0; |
| |
| bio = do_mpage_readpage(bio, page, 1, |
| &last_block_in_bio, get_block); |
| if (bio) |
| mpage_bio_submit(READ, bio); |
| return 0; |
| } |
| EXPORT_SYMBOL(mpage_readpage); |
| |
| /* |
| * Writing is not so simple. |
| * |
| * If the page has buffers then they will be used for obtaining the disk |
| * mapping. We only support pages which are fully mapped-and-dirty, with a |
| * special case for pages which are unmapped at the end: end-of-file. |
| * |
| * If the page has no buffers (preferred) then the page is mapped here. |
| * |
| * If all blocks are found to be contiguous then the page can go into the |
| * BIO. Otherwise fall back to the mapping's writepage(). |
| * |
| * FIXME: This code wants an estimate of how many pages are still to be |
| * written, so it can intelligently allocate a suitably-sized BIO. For now, |
| * just allocate full-size (16-page) BIOs. |
| */ |
| static struct bio * |
| __mpage_writepage(struct bio *bio, struct page *page, get_block_t get_block, |
| sector_t *last_block_in_bio, int *ret, struct writeback_control *wbc, |
| writepage_t writepage_fn) |
| { |
| struct address_space *mapping = page->mapping; |
| struct inode *inode = page->mapping->host; |
| const unsigned blkbits = inode->i_blkbits; |
| unsigned long end_index; |
| const unsigned blocks_per_page = PAGE_CACHE_SIZE >> blkbits; |
| sector_t last_block; |
| sector_t block_in_file; |
| sector_t blocks[MAX_BUF_PER_PAGE]; |
| unsigned page_block; |
| unsigned first_unmapped = blocks_per_page; |
| struct block_device *bdev = NULL; |
| int boundary = 0; |
| sector_t boundary_block = 0; |
| struct block_device *boundary_bdev = NULL; |
| int length; |
| struct buffer_head map_bh; |
| loff_t i_size = i_size_read(inode); |
| |
| if (page_has_buffers(page)) { |
| struct buffer_head *head = page_buffers(page); |
| struct buffer_head *bh = head; |
| |
| /* If they're all mapped and dirty, do it */ |
| page_block = 0; |
| do { |
| BUG_ON(buffer_locked(bh)); |
| if (!buffer_mapped(bh)) { |
| /* |
| * unmapped dirty buffers are created by |
| * __set_page_dirty_buffers -> mmapped data |
| */ |
| if (buffer_dirty(bh)) |
| goto confused; |
| if (first_unmapped == blocks_per_page) |
| first_unmapped = page_block; |
| continue; |
| } |
| |
| if (first_unmapped != blocks_per_page) |
| goto confused; /* hole -> non-hole */ |
| |
| if (!buffer_dirty(bh) || !buffer_uptodate(bh)) |
| goto confused; |
| if (page_block) { |
| if (bh->b_blocknr != blocks[page_block-1] + 1) |
| goto confused; |
| } |
| blocks[page_block++] = bh->b_blocknr; |
| boundary = buffer_boundary(bh); |
| if (boundary) { |
| boundary_block = bh->b_blocknr; |
| boundary_bdev = bh->b_bdev; |
| } |
| bdev = bh->b_bdev; |
| } while ((bh = bh->b_this_page) != head); |
| |
| if (first_unmapped) |
| goto page_is_mapped; |
| |
| /* |
| * Page has buffers, but they are all unmapped. The page was |
| * created by pagein or read over a hole which was handled by |
| * block_read_full_page(). If this address_space is also |
| * using mpage_readpages then this can rarely happen. |
| */ |
| goto confused; |
| } |
| |
| /* |
| * The page has no buffers: map it to disk |
| */ |
| BUG_ON(!PageUptodate(page)); |
| block_in_file = page->index << (PAGE_CACHE_SHIFT - blkbits); |
| last_block = (i_size - 1) >> blkbits; |
| map_bh.b_page = page; |
| for (page_block = 0; page_block < blocks_per_page; ) { |
| |
| map_bh.b_state = 0; |
| if (get_block(inode, block_in_file, &map_bh, 1)) |
| goto confused; |
| if (buffer_new(&map_bh)) |
| unmap_underlying_metadata(map_bh.b_bdev, |
| map_bh.b_blocknr); |
| if (buffer_boundary(&map_bh)) { |
| boundary_block = map_bh.b_blocknr; |
| boundary_bdev = map_bh.b_bdev; |
| } |
| if (page_block) { |
| if (map_bh.b_blocknr != blocks[page_block-1] + 1) |
| goto confused; |
| } |
| blocks[page_block++] = map_bh.b_blocknr; |
| boundary = buffer_boundary(&map_bh); |
| bdev = map_bh.b_bdev; |
| if (block_in_file == last_block) |
| break; |
| block_in_file++; |
| } |
| BUG_ON(page_block == 0); |
| |
| first_unmapped = page_block; |
| |
| page_is_mapped: |
| end_index = i_size >> PAGE_CACHE_SHIFT; |
| if (page->index >= end_index) { |
| /* |
| * The page straddles i_size. It must be zeroed out on each |
| * and every writepage invokation because it may be mmapped. |
| * "A file is mapped in multiples of the page size. For a file |
| * that is not a multiple of the page size, the remaining memory |
| * is zeroed when mapped, and writes to that region are not |
| * written out to the file." |
| */ |
| unsigned offset = i_size & (PAGE_CACHE_SIZE - 1); |
| char *kaddr; |
| |
| if (page->index > end_index || !offset) |
| goto confused; |
| kaddr = kmap_atomic(page, KM_USER0); |
| memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset); |
| flush_dcache_page(page); |
| kunmap_atomic(kaddr, KM_USER0); |
| } |
| |
| /* |
| * This page will go to BIO. Do we need to send this BIO off first? |
| */ |
| if (bio && *last_block_in_bio != blocks[0] - 1) |
| bio = mpage_bio_submit(WRITE, bio); |
| |
| alloc_new: |
| if (bio == NULL) { |
| bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9), |
| bio_get_nr_vecs(bdev), GFP_NOFS|__GFP_HIGH); |
| if (bio == NULL) |
| goto confused; |
| } |
| |
| /* |
| * Must try to add the page before marking the buffer clean or |
| * the confused fail path above (OOM) will be very confused when |
| * it finds all bh marked clean (i.e. it will not write anything) |
| */ |
| length = first_unmapped << blkbits; |
| if (bio_add_page(bio, page, length, 0) < length) { |
| bio = mpage_bio_submit(WRITE, bio); |
| goto alloc_new; |
| } |
| |
| /* |
| * OK, we have our BIO, so we can now mark the buffers clean. Make |
| * sure to only clean buffers which we know we'll be writing. |
| */ |
| if (page_has_buffers(page)) { |
| struct buffer_head *head = page_buffers(page); |
| struct buffer_head *bh = head; |
| unsigned buffer_counter = 0; |
| |
| do { |
| if (buffer_counter++ == first_unmapped) |
| break; |
| clear_buffer_dirty(bh); |
| bh = bh->b_this_page; |
| } while (bh != head); |
| |
| /* |
| * we cannot drop the bh if the page is not uptodate |
| * or a concurrent readpage would fail to serialize with the bh |
| * and it would read from disk before we reach the platter. |
| */ |
| if (buffer_heads_over_limit && PageUptodate(page)) |
| try_to_free_buffers(page); |
| } |
| |
| BUG_ON(PageWriteback(page)); |
| set_page_writeback(page); |
| unlock_page(page); |
| if (boundary || (first_unmapped != blocks_per_page)) { |
| bio = mpage_bio_submit(WRITE, bio); |
| if (boundary_block) { |
| write_boundary_block(boundary_bdev, |
| boundary_block, 1 << blkbits); |
| } |
| } else { |
| *last_block_in_bio = blocks[blocks_per_page - 1]; |
| } |
| goto out; |
| |
| confused: |
| if (bio) |
| bio = mpage_bio_submit(WRITE, bio); |
| |
| if (writepage_fn) { |
| *ret = (*writepage_fn)(page, wbc); |
| } else { |
| *ret = -EAGAIN; |
| goto out; |
| } |
| /* |
| * The caller has a ref on the inode, so *mapping is stable |
| */ |
| if (*ret) { |
| if (*ret == -ENOSPC) |
| set_bit(AS_ENOSPC, &mapping->flags); |
| else |
| set_bit(AS_EIO, &mapping->flags); |
| } |
| out: |
| return bio; |
| } |
| |
| /** |
| * mpage_writepages - walk the list of dirty pages of the given |
| * address space and writepage() all of them. |
| * |
| * @mapping: address space structure to write |
| * @wbc: subtract the number of written pages from *@wbc->nr_to_write |
| * @get_block: the filesystem's block mapper function. |
| * If this is NULL then use a_ops->writepage. Otherwise, go |
| * direct-to-BIO. |
| * |
| * This is a library function, which implements the writepages() |
| * address_space_operation. |
| * |
| * If a page is already under I/O, generic_writepages() skips it, even |
| * if it's dirty. This is desirable behaviour for memory-cleaning writeback, |
| * but it is INCORRECT for data-integrity system calls such as fsync(). fsync() |
| * and msync() need to guarantee that all the data which was dirty at the time |
| * the call was made get new I/O started against them. If wbc->sync_mode is |
| * WB_SYNC_ALL then we were called for data integrity and we must wait for |
| * existing IO to complete. |
| */ |
| int |
| mpage_writepages(struct address_space *mapping, |
| struct writeback_control *wbc, get_block_t get_block) |
| { |
| struct backing_dev_info *bdi = mapping->backing_dev_info; |
| struct bio *bio = NULL; |
| sector_t last_block_in_bio = 0; |
| int ret = 0; |
| int done = 0; |
| int (*writepage)(struct page *page, struct writeback_control *wbc); |
| struct pagevec pvec; |
| int nr_pages; |
| pgoff_t index; |
| pgoff_t end = -1; /* Inclusive */ |
| int scanned = 0; |
| int is_range = 0; |
| |
| if (wbc->nonblocking && bdi_write_congested(bdi)) { |
| wbc->encountered_congestion = 1; |
| return 0; |
| } |
| |
| writepage = NULL; |
| if (get_block == NULL) |
| writepage = mapping->a_ops->writepage; |
| |
| pagevec_init(&pvec, 0); |
| if (wbc->sync_mode == WB_SYNC_NONE) { |
| index = mapping->writeback_index; /* Start from prev offset */ |
| } else { |
| index = 0; /* whole-file sweep */ |
| scanned = 1; |
| } |
| if (wbc->start || wbc->end) { |
| index = wbc->start >> PAGE_CACHE_SHIFT; |
| end = wbc->end >> PAGE_CACHE_SHIFT; |
| is_range = 1; |
| scanned = 1; |
| } |
| retry: |
| while (!done && (index <= end) && |
| (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, |
| PAGECACHE_TAG_DIRTY, |
| min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) { |
| unsigned i; |
| |
| scanned = 1; |
| for (i = 0; i < nr_pages; i++) { |
| struct page *page = pvec.pages[i]; |
| |
| /* |
| * At this point we hold neither mapping->tree_lock nor |
| * lock on the page itself: the page may be truncated or |
| * invalidated (changing page->mapping to NULL), or even |
| * swizzled back from swapper_space to tmpfs file |
| * mapping |
| */ |
| |
| lock_page(page); |
| |
| if (unlikely(page->mapping != mapping)) { |
| unlock_page(page); |
| continue; |
| } |
| |
| if (unlikely(is_range) && page->index > end) { |
| done = 1; |
| unlock_page(page); |
| continue; |
| } |
| |
| if (wbc->sync_mode != WB_SYNC_NONE) |
| wait_on_page_writeback(page); |
| |
| if (PageWriteback(page) || |
| !clear_page_dirty_for_io(page)) { |
| unlock_page(page); |
| continue; |
| } |
| |
| if (writepage) { |
| ret = (*writepage)(page, wbc); |
| if (ret) { |
| if (ret == -ENOSPC) |
| set_bit(AS_ENOSPC, |
| &mapping->flags); |
| else |
| set_bit(AS_EIO, |
| &mapping->flags); |
| } |
| } else { |
| bio = __mpage_writepage(bio, page, get_block, |
| &last_block_in_bio, &ret, wbc, |
| page->mapping->a_ops->writepage); |
| } |
| if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) |
| unlock_page(page); |
| if (ret || (--(wbc->nr_to_write) <= 0)) |
| done = 1; |
| if (wbc->nonblocking && bdi_write_congested(bdi)) { |
| wbc->encountered_congestion = 1; |
| done = 1; |
| } |
| } |
| pagevec_release(&pvec); |
| cond_resched(); |
| } |
| if (!scanned && !done) { |
| /* |
| * We hit the last page and there is more work to be done: wrap |
| * back to the start of the file |
| */ |
| scanned = 1; |
| index = 0; |
| goto retry; |
| } |
| if (!is_range) |
| mapping->writeback_index = index; |
| if (bio) |
| mpage_bio_submit(WRITE, bio); |
| return ret; |
| } |
| EXPORT_SYMBOL(mpage_writepages); |
| |
| int mpage_writepage(struct page *page, get_block_t get_block, |
| struct writeback_control *wbc) |
| { |
| int ret = 0; |
| struct bio *bio; |
| sector_t last_block_in_bio = 0; |
| |
| bio = __mpage_writepage(NULL, page, get_block, |
| &last_block_in_bio, &ret, wbc, NULL); |
| if (bio) |
| mpage_bio_submit(WRITE, bio); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(mpage_writepage); |