From 4a0f9a321a113392b448e477018311d14fba2b34 Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Mon, 20 Apr 2009 08:16:26 +0100 Subject: [PATCH] GFS2: Optimise writepage for metadata This adds a GFS2 specific writepage for metadata, rather than continuing to use the VFS function. As a result we now tag all our metadata I/O with the correct flag so that blktraces will now be less confusing. Also, the generic function was checking for a number of corner cases which cannot happen on the metadata address spaces so that this should be faster too. Signed-off-by: Steven Whitehouse --- fs/gfs2/meta_io.c | 66 ++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 57 insertions(+), 9 deletions(-) diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c index 75b2aec06f85..78a5f4312667 100644 --- a/fs/gfs2/meta_io.c +++ b/fs/gfs2/meta_io.c @@ -33,17 +33,65 @@ #include "util.h" #include "ops_address.h" -static int aspace_get_block(struct inode *inode, sector_t lblock, - struct buffer_head *bh_result, int create) +static int gfs2_aspace_writepage(struct page *page, struct writeback_control *wbc) { - gfs2_assert_warn(inode->i_sb->s_fs_info, 0); - return -EOPNOTSUPP; -} + int err; + struct buffer_head *bh, *head; + int nr_underway = 0; + int write_op = (1 << BIO_RW_META) | ((wbc->sync_mode == WB_SYNC_ALL ? + WRITE_SYNC_PLUG : WRITE)); + + BUG_ON(!PageLocked(page)); + BUG_ON(!page_has_buffers(page)); + + head = page_buffers(page); + bh = head; + + do { + if (!buffer_mapped(bh)) + continue; + /* + * If it's a fully non-blocking write attempt and we cannot + * lock the buffer then redirty the page. Note that this can + * potentially cause a busy-wait loop from pdflush and kswapd + * activity, but those code paths have their own higher-level + * throttling. + */ + if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) { + lock_buffer(bh); + } else if (!trylock_buffer(bh)) { + redirty_page_for_writepage(wbc, page); + continue; + } + if (test_clear_buffer_dirty(bh)) { + mark_buffer_async_write(bh); + } else { + unlock_buffer(bh); + } + } while ((bh = bh->b_this_page) != head); + + /* + * The page and its buffers are protected by PageWriteback(), so we can + * drop the bh refcounts early. + */ + BUG_ON(PageWriteback(page)); + set_page_writeback(page); + + do { + struct buffer_head *next = bh->b_this_page; + if (buffer_async_write(bh)) { + submit_bh(write_op, bh); + nr_underway++; + } + bh = next; + } while (bh != head); + unlock_page(page); -static int gfs2_aspace_writepage(struct page *page, - struct writeback_control *wbc) -{ - return block_write_full_page(page, aspace_get_block, wbc); + err = 0; + if (nr_underway == 0) + end_page_writeback(page); + + return err; } static const struct address_space_operations aspace_aops = { -- 2.39.2