These functions are to be called from filesystem implementations of write_begin and write_end. They correspond to block_write_begin, generic_write_end and block_write_end. The old functions need to be kept around as they're used as function pointers. Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> --- fs/buffer.c | 80 ++++++++++++++++++++++++++----------- include/linux/buffer_head.h | 6 +++ 2 files changed, 63 insertions(+), 23 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index 58ac52f20bf6..4064b21fe499 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -2217,39 +2217,55 @@ static void __block_commit_write(struct folio *folio, size_t from, size_t to) } /* - * block_write_begin takes care of the basic task of block allocation and + * buffer_write_begin - Helper for filesystem write_begin implementations + * @mapping: Address space being written to. + * @pos: Position in bytes within the file. + * @len: Number of bytes being written. + * @get_block: How to get buffer_heads for this filesystem. + * + * Take care of the basic task of block allocation and * bringing partial write blocks uptodate first. * * The filesystem needs to handle block truncation upon failure. + * + * Return: The folio to write to, or an ERR_PTR on failure. */ -int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len, - struct page **pagep, get_block_t *get_block) +struct folio *buffer_write_begin(struct address_space *mapping, loff_t pos, + size_t len, get_block_t *get_block) { - pgoff_t index = pos >> PAGE_SHIFT; - struct page *page; + struct folio *folio = __filemap_get_folio(mapping, pos / PAGE_SIZE, + FGP_WRITEBEGIN, mapping_gfp_mask(mapping)); int status; - page = grab_cache_page_write_begin(mapping, index); - if (!page) - return -ENOMEM; + if (IS_ERR(folio)) + return folio; - status = __block_write_begin(page, pos, len, get_block); + status = __block_write_begin_int(folio, pos, len, get_block, NULL); if (unlikely(status)) { - unlock_page(page); - put_page(page); - page = NULL; + folio_unlock(folio); + folio_put(folio); + folio = ERR_PTR(status); } - *pagep = page; - return status; + return folio; +} +EXPORT_SYMBOL(buffer_write_begin); + +int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len, + struct page **pagep, get_block_t *get_block) +{ + struct folio *folio = buffer_write_begin(mapping, pos, len, get_block); + + if (IS_ERR(folio)) + return PTR_ERR(folio); + *pagep = &folio->page; + return 0; } EXPORT_SYMBOL(block_write_begin); -int block_write_end(struct file *file, struct address_space *mapping, - loff_t pos, unsigned len, unsigned copied, - struct page *page, void *fsdata) +size_t __buffer_write_end(struct file *file, struct address_space *mapping, + loff_t pos, size_t len, size_t copied, struct folio *folio) { - struct folio *folio = page_folio(page); size_t start = pos - folio_pos(folio); if (unlikely(copied < len)) { @@ -2277,17 +2293,26 @@ int block_write_end(struct file *file, struct address_space *mapping, return copied; } -EXPORT_SYMBOL(block_write_end); +EXPORT_SYMBOL(__buffer_write_end); -int generic_write_end(struct file *file, struct address_space *mapping, +int block_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) +{ + return buffer_write_end(file, mapping, pos, len, copied, + page_folio(page)); +} +EXPORT_SYMBOL(block_write_end); + +size_t buffer_write_end(struct file *file, struct address_space *mapping, + loff_t pos, size_t len, size_t copied, + struct folio *folio) { struct inode *inode = mapping->host; loff_t old_size = inode->i_size; bool i_size_changed = false; - copied = block_write_end(file, mapping, pos, len, copied, page, fsdata); + copied = __buffer_write_end(file, mapping, pos, len, copied, folio); /* * No need to use i_size_read() here, the i_size cannot change under us @@ -2301,8 +2326,8 @@ int generic_write_end(struct file *file, struct address_space *mapping, i_size_changed = true; } - unlock_page(page); - put_page(page); + folio_unlock(folio); + folio_put(folio); if (old_size < pos) pagecache_isize_extended(inode, old_size, pos); @@ -2316,6 +2341,15 @@ int generic_write_end(struct file *file, struct address_space *mapping, mark_inode_dirty(inode); return copied; } +EXPORT_SYMBOL(buffer_write_end); + +int generic_write_end(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, void *fsdata) +{ + return buffer_write_end(file, mapping, pos, len, copied, + page_folio(page)); +} EXPORT_SYMBOL(generic_write_end); /* diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 1b7f14e39ab8..44e4b2b18cc0 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -267,6 +267,12 @@ int block_write_end(struct file *, struct address_space *, int generic_write_end(struct file *, struct address_space *, loff_t, unsigned, unsigned, struct page *, void *); +struct folio *buffer_write_begin(struct address_space *mapping, loff_t pos, + size_t len, get_block_t *get_block); +size_t buffer_write_end(struct file *, struct address_space *, loff_t pos, + size_t len, size_t copied, struct folio *); +size_t __buffer_write_end(struct file *, struct address_space *, loff_t pos, + size_t len, size_t copied, struct folio *); void folio_zero_new_buffers(struct folio *folio, size_t from, size_t to); int cont_write_begin(struct file *, struct address_space *, loff_t pos, unsigned len, struct page **, void **fsdata, get_block_t *, -- 2.43.0