From: Lukas Czerner Date: Tue, 28 May 2013 03:32:35 +0000 (-0400) Subject: ext4: remove unused discard_partial_page_buffers X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=c121ffd013e5ab7c04414a5f0cb3604731775174;p=openwrt%2Fstaging%2Fblogic.git ext4: remove unused discard_partial_page_buffers The discard_partial_page_buffers is no longer used anywhere so we can simply remove it including the *_no_lock variant and EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED define. Signed-off-by: Lukas Czerner Reviewed-by: Jan Kara Signed-off-by: Theodore Ts'o --- diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 2d4b0aa74859..019db3c1bc3b 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -580,11 +580,6 @@ enum { #define EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER 0x0010 #define EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER 0x0020 -/* - * Flags used by ext4_discard_partial_page_buffers - */ -#define EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED 0x0001 - /* * ioctl commands */ @@ -2102,9 +2097,6 @@ extern int ext4_block_zero_page_range(handle_t *handle, struct address_space *mapping, loff_t from, loff_t length); extern int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode, loff_t lstart, loff_t lend); -extern int ext4_discard_partial_page_buffers(handle_t *handle, - struct address_space *mapping, loff_t from, - loff_t length, int flags); extern int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf); extern qsize_t *ext4_get_reserved_space(struct inode *inode); extern void ext4_da_update_reserve_space(struct inode *inode, diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 3acf353493d4..0fca5a8c6d3e 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -136,9 +136,6 @@ static void ext4_invalidatepage(struct page *page, unsigned int offset, unsigned int length); static int __ext4_journalled_writepage(struct page *page, unsigned int len); static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh); -static int ext4_discard_partial_page_buffers_no_lock(handle_t *handle, - struct inode *inode, struct page *page, loff_t from, - loff_t length, int flags); /* * Test whether an inode is a fast symlink. @@ -3367,209 +3364,6 @@ void ext4_set_aops(struct inode *inode) inode->i_mapping->a_ops = &ext4_aops; } - -/* - * ext4_discard_partial_page_buffers() - * Wrapper function for ext4_discard_partial_page_buffers_no_lock. - * This function finds and locks the page containing the offset - * "from" and passes it to ext4_discard_partial_page_buffers_no_lock. - * Calling functions that already have the page locked should call - * ext4_discard_partial_page_buffers_no_lock directly. - */ -int ext4_discard_partial_page_buffers(handle_t *handle, - struct address_space *mapping, loff_t from, - loff_t length, int flags) -{ - struct inode *inode = mapping->host; - struct page *page; - int err = 0; - - page = find_or_create_page(mapping, from >> PAGE_CACHE_SHIFT, - mapping_gfp_mask(mapping) & ~__GFP_FS); - if (!page) - return -ENOMEM; - - err = ext4_discard_partial_page_buffers_no_lock(handle, inode, page, - from, length, flags); - - unlock_page(page); - page_cache_release(page); - return err; -} - -/* - * ext4_discard_partial_page_buffers_no_lock() - * Zeros a page range of length 'length' starting from offset 'from'. - * Buffer heads that correspond to the block aligned regions of the - * zeroed range will be unmapped. Unblock aligned regions - * will have the corresponding buffer head mapped if needed so that - * that region of the page can be updated with the partial zero out. - * - * This function assumes that the page has already been locked. The - * The range to be discarded must be contained with in the given page. - * If the specified range exceeds the end of the page it will be shortened - * to the end of the page that corresponds to 'from'. This function is - * appropriate for updating a page and it buffer heads to be unmapped and - * zeroed for blocks that have been either released, or are going to be - * released. - * - * handle: The journal handle - * inode: The files inode - * page: A locked page that contains the offset "from" - * from: The starting byte offset (from the beginning of the file) - * to begin discarding - * len: The length of bytes to discard - * flags: Optional flags that may be used: - * - * EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED - * Only zero the regions of the page whose buffer heads - * have already been unmapped. This flag is appropriate - * for updating the contents of a page whose blocks may - * have already been released, and we only want to zero - * out the regions that correspond to those released blocks. - * - * Returns zero on success or negative on failure. - */ -static int ext4_discard_partial_page_buffers_no_lock(handle_t *handle, - struct inode *inode, struct page *page, loff_t from, - loff_t length, int flags) -{ - ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT; - unsigned int offset = from & (PAGE_CACHE_SIZE-1); - unsigned int blocksize, max, pos; - ext4_lblk_t iblock; - struct buffer_head *bh; - int err = 0; - - blocksize = inode->i_sb->s_blocksize; - max = PAGE_CACHE_SIZE - offset; - - if (index != page->index) - return -EINVAL; - - /* - * correct length if it does not fall between - * 'from' and the end of the page - */ - if (length > max || length < 0) - length = max; - - iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits); - - if (!page_has_buffers(page)) - create_empty_buffers(page, blocksize, 0); - - /* Find the buffer that contains "offset" */ - bh = page_buffers(page); - pos = blocksize; - while (offset >= pos) { - bh = bh->b_this_page; - iblock++; - pos += blocksize; - } - - pos = offset; - while (pos < offset + length) { - unsigned int end_of_block, range_to_discard; - - err = 0; - - /* The length of space left to zero and unmap */ - range_to_discard = offset + length - pos; - - /* The length of space until the end of the block */ - end_of_block = blocksize - (pos & (blocksize-1)); - - /* - * Do not unmap or zero past end of block - * for this buffer head - */ - if (range_to_discard > end_of_block) - range_to_discard = end_of_block; - - - /* - * Skip this buffer head if we are only zeroing unampped - * regions of the page - */ - if (flags & EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED && - buffer_mapped(bh)) - goto next; - - /* If the range is block aligned, unmap */ - if (range_to_discard == blocksize) { - clear_buffer_dirty(bh); - bh->b_bdev = NULL; - clear_buffer_mapped(bh); - clear_buffer_req(bh); - clear_buffer_new(bh); - clear_buffer_delay(bh); - clear_buffer_unwritten(bh); - clear_buffer_uptodate(bh); - zero_user(page, pos, range_to_discard); - BUFFER_TRACE(bh, "Buffer discarded"); - goto next; - } - - /* - * If this block is not completely contained in the range - * to be discarded, then it is not going to be released. Because - * we need to keep this block, we need to make sure this part - * of the page is uptodate before we modify it by writeing - * partial zeros on it. - */ - if (!buffer_mapped(bh)) { - /* - * Buffer head must be mapped before we can read - * from the block - */ - BUFFER_TRACE(bh, "unmapped"); - ext4_get_block(inode, iblock, bh, 0); - /* unmapped? It's a hole - nothing to do */ - if (!buffer_mapped(bh)) { - BUFFER_TRACE(bh, "still unmapped"); - goto next; - } - } - - /* Ok, it's mapped. Make sure it's up-to-date */ - if (PageUptodate(page)) - set_buffer_uptodate(bh); - - if (!buffer_uptodate(bh)) { - err = -EIO; - ll_rw_block(READ, 1, &bh); - wait_on_buffer(bh); - /* Uhhuh. Read error. Complain and punt.*/ - if (!buffer_uptodate(bh)) - goto next; - } - - if (ext4_should_journal_data(inode)) { - BUFFER_TRACE(bh, "get write access"); - err = ext4_journal_get_write_access(handle, bh); - if (err) - goto next; - } - - zero_user(page, pos, range_to_discard); - - err = 0; - if (ext4_should_journal_data(inode)) { - err = ext4_handle_dirty_metadata(handle, inode, bh); - } else - mark_buffer_dirty(bh); - - BUFFER_TRACE(bh, "Partial buffer zeroed"); -next: - bh = bh->b_this_page; - iblock++; - pos += range_to_discard; - } - - return err; -} - /* * ext4_block_truncate_page() zeroes out a mapping from file offset `from' * up to the end of the block which corresponds to `from'.