From fd88de569b802c4a04aaa6ee74667775f4aed8c6 Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Fri, 5 May 2006 16:59:11 -0400 Subject: [GFS2] Readpages support This adds readpages support (and also corrects a small bug in the readpage error path at the same time). Hopefully this will improve performance by allowing GFS to submit larger lumps of I/O at a time. In order to simplify the setting of BH_Boundary, it currently gets set when we hit the end of a indirect pointer block. There is always a boundary at this point with the current allocation code. It doesn't get all the boundaries right though, so there is still room for improvement in this. See comments in fs/gfs2/ops_address.c for further information about readpages with GFS2. Signed-off-by: Steven Whitehouse --- fs/gfs2/ops_address.c | 145 ++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 117 insertions(+), 28 deletions(-) (limited to 'fs/gfs2/ops_address.c') diff --git a/fs/gfs2/ops_address.c b/fs/gfs2/ops_address.c index afcc12a00a3..d89179b316f 100644 --- a/fs/gfs2/ops_address.c +++ b/fs/gfs2/ops_address.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include @@ -47,12 +48,12 @@ int gfs2_get_block(struct inode *inode, sector_t lblock, struct buffer_head *bh_result, int create) { - struct gfs2_inode *ip = inode->u.generic_ip; int new = create; uint64_t dblock; int error; + int boundary; - error = gfs2_block_map(ip, lblock, &new, &dblock, NULL); + error = gfs2_block_map(inode, lblock, &new, &dblock, &boundary); if (error) return error; @@ -62,6 +63,8 @@ int gfs2_get_block(struct inode *inode, sector_t lblock, map_bh(bh_result, inode->i_sb, dblock); if (new) set_buffer_new(bh_result); + if (boundary) + set_buffer_boundary(bh_result); return 0; } @@ -83,8 +86,9 @@ static int get_block_noalloc(struct inode *inode, sector_t lblock, int new = 0; uint64_t dblock; int error; + int boundary; - error = gfs2_block_map(ip, lblock, &new, &dblock, NULL); + error = gfs2_block_map(inode, lblock, &new, &dblock, &boundary); if (error) return error; @@ -92,6 +96,8 @@ static int get_block_noalloc(struct inode *inode, sector_t lblock, map_bh(bh_result, inode->i_sb, dblock); else if (gfs2_assert_withdraw(ip->i_sbd, !create)) error = -EIO; + if (boundary) + set_buffer_boundary(bh_result); return error; } @@ -151,6 +157,19 @@ out_ignore: return 0; } +static int zero_readpage(struct page *page) +{ + void *kaddr; + + kaddr = kmap_atomic(page, KM_USER0); + memset(kaddr, 0, PAGE_CACHE_SIZE); + kunmap_atomic(page, KM_USER0); + + SetPageUptodate(page); + + return 0; +} + /** * stuffed_readpage - Fill in a Linux page with stuffed file data * @ip: the inode @@ -165,17 +184,18 @@ static int stuffed_readpage(struct gfs2_inode *ip, struct page *page) void *kaddr; int error; + /* Only the first page of a stuffed file might contain data */ + if (unlikely(page->index)) + return zero_readpage(page); + error = gfs2_meta_inode_buffer(ip, &dibh); if (error) return error; kaddr = kmap_atomic(page, KM_USER0); - memcpy((char *)kaddr, - dibh->b_data + sizeof(struct gfs2_dinode), + memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), ip->i_di.di_size); - memset((char *)kaddr + ip->i_di.di_size, - 0, - PAGE_CACHE_SIZE - ip->i_di.di_size); + memset(kaddr + ip->i_di.di_size, 0, PAGE_CACHE_SIZE - ip->i_di.di_size); kunmap_atomic(page, KM_USER0); brelse(dibh); @@ -185,19 +205,6 @@ static int stuffed_readpage(struct gfs2_inode *ip, struct page *page) return 0; } -static int zero_readpage(struct page *page) -{ - void *kaddr; - - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr, 0, PAGE_CACHE_SIZE); - kunmap_atomic(page, KM_USER0); - - SetPageUptodate(page); - unlock_page(page); - - return 0; -} /** * gfs2_readpage - readpage with locking @@ -215,19 +222,16 @@ static int gfs2_readpage(struct file *file, struct page *page) struct gfs2_holder gh; int error; - if (file != &gfs2_internal_file_sentinal) { + if (likely(file != &gfs2_internal_file_sentinal)) { gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME|GL_AOP, &gh); error = gfs2_glock_nq_m_atime(1, &gh); - if (error) + if (unlikely(error)) goto out_unlock; } if (gfs2_is_stuffed(ip)) { - if (!page->index) { - error = stuffed_readpage(ip, page); - unlock_page(page); - } else - error = zero_readpage(page); + error = stuffed_readpage(ip, page); + unlock_page(page); } else error = mpage_readpage(page, gfs2_get_block); @@ -242,6 +246,90 @@ out: return error; out_unlock: unlock_page(page); + if (file != &gfs2_internal_file_sentinal) + gfs2_holder_uninit(&gh); + goto out; +} + +#define list_to_page(head) (list_entry((head)->prev, struct page, lru)) + +/** + * gfs2_readpages - Read a bunch of pages at once + * + * Some notes: + * 1. This is only for readahead, so we can simply ignore any things + * which are slightly inconvenient (such as locking conflicts between + * the page lock and the glock) and return having done no I/O. Its + * obviously not something we'd want to do on too regular a basis. + * Any I/O we ignore at this time will be done via readpage later. + * 2. We have to handle stuffed files here too. + * 3. mpage_readpages() does most of the heavy lifting in the common case. + * 4. gfs2_get_block() is relied upon to set BH_Boundary in the right places. + * 5. We use LM_FLAG_TRY_1CB here, effectively we then have lock-ahead as + * well as read-ahead. + */ +static int gfs2_readpages(struct file *file, struct address_space *mapping, + struct list_head *pages, unsigned nr_pages) +{ + struct inode *inode = mapping->host; + struct gfs2_inode *ip = inode->u.generic_ip; + struct gfs2_sbd *sdp = ip->i_sbd; + struct gfs2_holder gh; + unsigned page_idx; + int ret; + + if (likely(file != &gfs2_internal_file_sentinal)) { + gfs2_holder_init(ip->i_gl, LM_ST_SHARED, + LM_FLAG_TRY_1CB|GL_ATIME|GL_AOP, &gh); + ret = gfs2_glock_nq_m_atime(1, &gh); + if (ret == GLR_TRYFAILED) + goto out_noerror; + if (unlikely(ret)) + goto out_unlock; + } + + if (gfs2_is_stuffed(ip)) { + struct pagevec lru_pvec; + pagevec_init(&lru_pvec, 0); + for (page_idx = 0; page_idx < nr_pages; page_idx++) { + struct page *page = list_to_page(pages); + list_del(&page->lru); + if (!add_to_page_cache(page, mapping, + page->index, GFP_KERNEL)) { + ret = stuffed_readpage(ip, page); + unlock_page(page); + if (!pagevec_add(&lru_pvec, page)) + __pagevec_lru_add(&lru_pvec); + } + page_cache_release(page); + } + pagevec_lru_add(&lru_pvec); + ret = 0; + } else { + /* What we really want to do .... */ + ret = mpage_readpages(mapping, pages, nr_pages, gfs2_get_block); + } + + if (likely(file != &gfs2_internal_file_sentinal)) { + gfs2_glock_dq_m(1, &gh); + gfs2_holder_uninit(&gh); + } +out: + if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) + ret = -EIO; + return ret; +out_noerror: + ret = 0; +out_unlock: + /* unlock all pages, we can't do any I/O right now */ + for (page_idx = 0; page_idx < nr_pages; page_idx++) { + struct page *page = list_to_page(pages); + list_del(&page->lru); + unlock_page(page); + page_cache_release(page); + } + if (likely(file != &gfs2_internal_file_sentinal)) + gfs2_holder_uninit(&gh); goto out; } @@ -572,6 +660,7 @@ static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb, struct address_space_operations gfs2_file_aops = { .writepage = gfs2_writepage, .readpage = gfs2_readpage, + .readpages = gfs2_readpages, .sync_page = block_sync_page, .prepare_write = gfs2_prepare_write, .commit_write = gfs2_commit_write, -- cgit v1.2.3