From 67235182a41c1bd6b32806a1556a1d299b84212b Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Mon, 6 Jun 2022 10:20:31 -0400 Subject: mm/migrate: Convert buffer_migrate_page() to buffer_migrate_folio() Use a folio throughout __buffer_migrate_folio(), add kernel-doc for buffer_migrate_folio() and buffer_migrate_folio_norefs(), move their declarations to buffer.h and switch all filesystems that have wired them up. Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig --- include/linux/buffer_head.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'include/linux/buffer_head.h') diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index c9d1463bb20f..b0366c89d6a4 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -267,6 +267,16 @@ int nobh_truncate_page(struct address_space *, loff_t, get_block_t *); int nobh_writepage(struct page *page, get_block_t *get_block, struct writeback_control *wbc); +#ifdef CONFIG_MIGRATION +extern int buffer_migrate_folio(struct address_space *, + struct folio *dst, struct folio *src, enum migrate_mode); +extern int buffer_migrate_folio_norefs(struct address_space *, + struct folio *dst, struct folio *src, enum migrate_mode); +#else +#define buffer_migrate_folio NULL +#define buffer_migrate_folio_norefs NULL +#endif + void buffer_init(void); /* -- cgit v1.2.3-59-g8ed1b From cc9cf350d100f4c336edb228cbd078003430cfe7 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 13 Jun 2022 07:37:13 +0200 Subject: fs: remove the nobh helpers All callers are gone, so remove the now dead code. Signed-off-by: Christoph Hellwig Reviewed-by: Jan Kara Signed-off-by: Matthew Wilcox (Oracle) --- fs/buffer.c | 324 -------------------------------------------- fs/mpage.c | 25 +--- include/linux/buffer_head.h | 8 -- include/linux/mpage.h | 2 - 4 files changed, 1 insertion(+), 358 deletions(-) (limited to 'include/linux/buffer_head.h') diff --git a/fs/buffer.c b/fs/buffer.c index ce9844d7c10f..5717d1881d2f 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -2537,330 +2537,6 @@ out_unlock: } EXPORT_SYMBOL(block_page_mkwrite); -/* - * nobh_write_begin()'s prereads are special: the buffer_heads are freed - * immediately, while under the page lock. So it needs a special end_io - * handler which does not touch the bh after unlocking it. - */ -static void end_buffer_read_nobh(struct buffer_head *bh, int uptodate) -{ - __end_buffer_read_notouch(bh, uptodate); -} - -/* - * Attach the singly-linked list of buffers created by nobh_write_begin, to - * the page (converting it to circular linked list and taking care of page - * dirty races). - */ -static void attach_nobh_buffers(struct page *page, struct buffer_head *head) -{ - struct buffer_head *bh; - - BUG_ON(!PageLocked(page)); - - spin_lock(&page->mapping->private_lock); - bh = head; - do { - if (PageDirty(page)) - set_buffer_dirty(bh); - if (!bh->b_this_page) - bh->b_this_page = head; - bh = bh->b_this_page; - } while (bh != head); - attach_page_private(page, head); - spin_unlock(&page->mapping->private_lock); -} - -/* - * On entry, the page is fully not uptodate. - * On exit the page is fully uptodate in the areas outside (from,to) - * The filesystem needs to handle block truncation upon failure. - */ -int nobh_write_begin(struct address_space *mapping, loff_t pos, unsigned len, - struct page **pagep, void **fsdata, - get_block_t *get_block) -{ - struct inode *inode = mapping->host; - const unsigned blkbits = inode->i_blkbits; - const unsigned blocksize = 1 << blkbits; - struct buffer_head *head, *bh; - struct page *page; - pgoff_t index; - unsigned from, to; - unsigned block_in_page; - unsigned block_start, block_end; - sector_t block_in_file; - int nr_reads = 0; - int ret = 0; - int is_mapped_to_disk = 1; - - index = pos >> PAGE_SHIFT; - from = pos & (PAGE_SIZE - 1); - to = from + len; - - page = grab_cache_page_write_begin(mapping, index); - if (!page) - return -ENOMEM; - *pagep = page; - *fsdata = NULL; - - if (page_has_buffers(page)) { - ret = __block_write_begin(page, pos, len, get_block); - if (unlikely(ret)) - goto out_release; - return ret; - } - - if (PageMappedToDisk(page)) - return 0; - - /* - * Allocate buffers so that we can keep track of state, and potentially - * attach them to the page if an error occurs. In the common case of - * no error, they will just be freed again without ever being attached - * to the page (which is all OK, because we're under the page lock). - * - * Be careful: the buffer linked list is a NULL terminated one, rather - * than the circular one we're used to. - */ - head = alloc_page_buffers(page, blocksize, false); - if (!head) { - ret = -ENOMEM; - goto out_release; - } - - block_in_file = (sector_t)page->index << (PAGE_SHIFT - blkbits); - - /* - * We loop across all blocks in the page, whether or not they are - * part of the affected region. This is so we can discover if the - * page is fully mapped-to-disk. - */ - for (block_start = 0, block_in_page = 0, bh = head; - block_start < PAGE_SIZE; - block_in_page++, block_start += blocksize, bh = bh->b_this_page) { - int create; - - block_end = block_start + blocksize; - bh->b_state = 0; - create = 1; - if (block_start >= to) - create = 0; - ret = get_block(inode, block_in_file + block_in_page, - bh, create); - if (ret) - goto failed; - if (!buffer_mapped(bh)) - is_mapped_to_disk = 0; - if (buffer_new(bh)) - clean_bdev_bh_alias(bh); - if (PageUptodate(page)) { - set_buffer_uptodate(bh); - continue; - } - if (buffer_new(bh) || !buffer_mapped(bh)) { - zero_user_segments(page, block_start, from, - to, block_end); - continue; - } - if (buffer_uptodate(bh)) - continue; /* reiserfs does this */ - if (block_start < from || block_end > to) { - lock_buffer(bh); - bh->b_end_io = end_buffer_read_nobh; - submit_bh(REQ_OP_READ, 0, bh); - nr_reads++; - } - } - - if (nr_reads) { - /* - * The page is locked, so these buffers are protected from - * any VM or truncate activity. Hence we don't need to care - * for the buffer_head refcounts. - */ - for (bh = head; bh; bh = bh->b_this_page) { - wait_on_buffer(bh); - if (!buffer_uptodate(bh)) - ret = -EIO; - } - if (ret) - goto failed; - } - - if (is_mapped_to_disk) - SetPageMappedToDisk(page); - - *fsdata = head; /* to be released by nobh_write_end */ - - return 0; - -failed: - BUG_ON(!ret); - /* - * Error recovery is a bit difficult. We need to zero out blocks that - * were newly allocated, and dirty them to ensure they get written out. - * Buffers need to be attached to the page at this point, otherwise - * the handling of potential IO errors during writeout would be hard - * (could try doing synchronous writeout, but what if that fails too?) - */ - attach_nobh_buffers(page, head); - page_zero_new_buffers(page, from, to); - -out_release: - unlock_page(page); - put_page(page); - *pagep = NULL; - - return ret; -} -EXPORT_SYMBOL(nobh_write_begin); - -int nobh_write_end(struct file *file, struct address_space *mapping, - loff_t pos, unsigned len, unsigned copied, - struct page *page, void *fsdata) -{ - struct inode *inode = page->mapping->host; - struct buffer_head *head = fsdata; - struct buffer_head *bh; - BUG_ON(fsdata != NULL && page_has_buffers(page)); - - if (unlikely(copied < len) && head) - attach_nobh_buffers(page, head); - if (page_has_buffers(page)) - return generic_write_end(file, mapping, pos, len, - copied, page, fsdata); - - SetPageUptodate(page); - set_page_dirty(page); - if (pos+copied > inode->i_size) { - i_size_write(inode, pos+copied); - mark_inode_dirty(inode); - } - - unlock_page(page); - put_page(page); - - while (head) { - bh = head; - head = head->b_this_page; - free_buffer_head(bh); - } - - return copied; -} -EXPORT_SYMBOL(nobh_write_end); - -/* - * nobh_writepage() - based on block_full_write_page() except - * that it tries to operate without attaching bufferheads to - * the page. - */ -int nobh_writepage(struct page *page, get_block_t *get_block, - struct writeback_control *wbc) -{ - struct inode * const inode = page->mapping->host; - loff_t i_size = i_size_read(inode); - const pgoff_t end_index = i_size >> PAGE_SHIFT; - unsigned offset; - int ret; - - /* Is the page fully inside i_size? */ - if (page->index < end_index) - goto out; - - /* Is the page fully outside i_size? (truncate in progress) */ - offset = i_size & (PAGE_SIZE-1); - if (page->index >= end_index+1 || !offset) { - unlock_page(page); - return 0; /* don't care */ - } - - /* - * The page straddles i_size. It must be zeroed out on each and every - * writepage invocation 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." - */ - zero_user_segment(page, offset, PAGE_SIZE); -out: - ret = mpage_writepage(page, get_block, wbc); - if (ret == -EAGAIN) - ret = __block_write_full_page(inode, page, get_block, wbc, - end_buffer_async_write); - return ret; -} -EXPORT_SYMBOL(nobh_writepage); - -int nobh_truncate_page(struct address_space *mapping, - loff_t from, get_block_t *get_block) -{ - pgoff_t index = from >> PAGE_SHIFT; - struct inode *inode = mapping->host; - unsigned blocksize = i_blocksize(inode); - struct folio *folio; - struct buffer_head map_bh; - size_t offset; - sector_t iblock; - int err; - - /* Block boundary? Nothing to do */ - if (!(from & (blocksize - 1))) - return 0; - - folio = __filemap_get_folio(mapping, index, FGP_LOCK | FGP_CREAT, - mapping_gfp_mask(mapping)); - err = -ENOMEM; - if (!folio) - goto out; - - if (folio_buffers(folio)) - goto has_buffers; - - iblock = from >> inode->i_blkbits; - map_bh.b_size = blocksize; - map_bh.b_state = 0; - err = get_block(inode, iblock, &map_bh, 0); - if (err) - goto unlock; - /* unmapped? It's a hole - nothing to do */ - if (!buffer_mapped(&map_bh)) - goto unlock; - - /* Ok, it's mapped. Make sure it's up-to-date */ - if (!folio_test_uptodate(folio)) { - err = mapping->a_ops->read_folio(NULL, folio); - if (err) { - folio_put(folio); - goto out; - } - folio_lock(folio); - if (!folio_test_uptodate(folio)) { - err = -EIO; - goto unlock; - } - if (folio_buffers(folio)) - goto has_buffers; - } - offset = offset_in_folio(folio, from); - folio_zero_segment(folio, offset, round_up(offset, blocksize)); - folio_mark_dirty(folio); - err = 0; - -unlock: - folio_unlock(folio); - folio_put(folio); -out: - return err; - -has_buffers: - folio_unlock(folio); - folio_put(folio); - return block_truncate_page(mapping, from, get_block); -} -EXPORT_SYMBOL(nobh_truncate_page); - int block_truncate_page(struct address_space *mapping, loff_t from, get_block_t *get_block) { diff --git a/fs/mpage.c b/fs/mpage.c index 681a4b9a36e3..b7e0b7fbb41f 100644 --- a/fs/mpage.c +++ b/fs/mpage.c @@ -404,7 +404,6 @@ struct mpage_data { struct bio *bio; sector_t last_block_in_bio; get_block_t *get_block; - unsigned use_writepage; }; /* @@ -624,15 +623,10 @@ confused: if (bio) bio = mpage_bio_submit(bio); - if (mpd->use_writepage) { - ret = mapping->a_ops->writepage(page, wbc); - } else { - ret = -EAGAIN; - goto out; - } /* * The caller has a ref on the inode, so *mapping is stable */ + ret = mapping->a_ops->writepage(page, wbc); mapping_set_error(mapping, ret); out: mpd->bio = bio; @@ -674,7 +668,6 @@ mpage_writepages(struct address_space *mapping, .bio = NULL, .last_block_in_bio = 0, .get_block = get_block, - .use_writepage = 1, }; ret = write_cache_pages(mapping, wbc, __mpage_writepage, &mpd); @@ -685,19 +678,3 @@ mpage_writepages(struct address_space *mapping, return ret; } EXPORT_SYMBOL(mpage_writepages); - -int mpage_writepage(struct page *page, get_block_t get_block, - struct writeback_control *wbc) -{ - struct mpage_data mpd = { - .bio = NULL, - .last_block_in_bio = 0, - .get_block = get_block, - .use_writepage = 0, - }; - int ret = __mpage_writepage(page, wbc, &mpd); - if (mpd.bio) - mpage_bio_submit(mpd.bio); - return ret; -} -EXPORT_SYMBOL(mpage_writepage); diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index b0366c89d6a4..61afb81cfdae 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -258,14 +258,6 @@ static inline vm_fault_t block_page_mkwrite_return(int err) } sector_t generic_block_bmap(struct address_space *, sector_t, get_block_t *); int block_truncate_page(struct address_space *, loff_t, get_block_t *); -int nobh_write_begin(struct address_space *, loff_t, unsigned len, - struct page **, void **, get_block_t*); -int nobh_write_end(struct file *, struct address_space *, - loff_t, unsigned, unsigned, - struct page *, void *); -int nobh_truncate_page(struct address_space *, loff_t, get_block_t *); -int nobh_writepage(struct page *page, get_block_t *get_block, - struct writeback_control *wbc); #ifdef CONFIG_MIGRATION extern int buffer_migrate_folio(struct address_space *, diff --git a/include/linux/mpage.h b/include/linux/mpage.h index 43986f7ec4dd..1bdc39daac0a 100644 --- a/include/linux/mpage.h +++ b/include/linux/mpage.h @@ -19,7 +19,5 @@ void mpage_readahead(struct readahead_control *, get_block_t get_block); int mpage_read_folio(struct folio *folio, get_block_t get_block); int mpage_writepages(struct address_space *mapping, struct writeback_control *wbc, get_block_t get_block); -int mpage_writepage(struct page *page, get_block_t *get_block, - struct writeback_control *wbc); #endif -- cgit v1.2.3-59-g8ed1b