diff options
author | Darrick J. Wong <djwong@kernel.org> | 2021-10-07 17:54:45 -0700 |
---|---|---|
committer | Darrick J. Wong <djwong@kernel.org> | 2021-10-22 16:41:17 -0700 |
commit | 014cdddffcddd5b13402721de744b9ea76961d74 (patch) | |
tree | 9c0641a8cfad09d0e02c9b9e57772a046d0f1a42 | |
parent | 04e01af9318f50df5e1974d8e2ce7d54b6cfbe55 (diff) |
xfs: use b_offset to support direct-mapping pages when blocksize < pagesizedirect-xfile-mapped-buffers_2021-10-22
Support using directly-mapped pages in the buffer cache when the fs
blocksize is less than the page size.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
-rw-r--r-- | fs/xfs/scrub/xfbtree.c | 2 | ||||
-rw-r--r-- | fs/xfs/xfs_buf.c | 32 |
2 files changed, 28 insertions, 6 deletions
diff --git a/fs/xfs/scrub/xfbtree.c b/fs/xfs/scrub/xfbtree.c index 1098234eec3b..bde856391c29 100644 --- a/fs/xfs/scrub/xfbtree.c +++ b/fs/xfs/scrub/xfbtree.c @@ -240,7 +240,7 @@ xfbtree_create( goto err_xfile; } - if (mp->m_bsize == PAGE_SIZE && (flags & XFBTREE_DIRECT_MAP)) + if (flags & XFBTREE_DIRECT_MAP) xfbt->target->bt_flags |= XFS_BUFTARG_DIRECT_MAP; xfbt->freespace = kmem_alloc(sizeof(struct xbitmap), diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index 5d1eebee2555..15259ccf212f 100644 --- a/fs/xfs/xfs_buf.c +++ b/fs/xfs/xfs_buf.c @@ -318,7 +318,7 @@ xfs_buf_free_pages( ASSERT(bp->b_flags & _XBF_PAGES); if (xfs_buf_is_vmapped(bp)) - vm_unmap_ram(bp->b_addr, bp->b_page_count); + vm_unmap_ram(bp->b_addr - bp->b_offset, bp->b_page_count); for (i = 0; i < bp->b_page_count; i++) { if (bp->b_pages[i]) @@ -438,6 +438,8 @@ xfs_buf_alloc_pages( XFS_STATS_INC(bp->b_mount, xb_page_retries); congestion_wait(BLK_RW_ASYNC, HZ / 50); } + + bp->b_offset = 0; return 0; } @@ -453,16 +455,32 @@ xfs_buf_alloc_direct_pages( struct xfs_buf_map *map; gfp_t gfp_mask = __GFP_NOWARN; const unsigned int page_align_mask = PAGE_SIZE - 1; + unsigned int first_page_offset; unsigned int m, p, n; int error; ASSERT(bp->b_target->bt_flags & XFS_BUFTARG_IN_MEMORY); - /* For direct-map buffers, each map has to be page aligned. */ - for (m = 0, map = bp->b_maps; m < bp->b_map_count; m++, map++) - if (BBTOB(map->bm_bn | map->bm_len) & page_align_mask) + /* + * For direct-map buffer targets with multiple mappings, the first map + * must end on a page boundary; the last map must start at a page + * boundary; and the maps in between must start and end on a page + * boundary. For single-mapping buffers, we don't care. + */ + if (bp->b_map_count > 1) { + map = &bp->b_maps[bp->b_map_count - 1]; + if (BBTOB(map->bm_bn) & page_align_mask) return -ENOTBLK; + map = &bp->b_maps[0]; + if (BBTOB(map->bm_bn + map->bm_len) & page_align_mask) + return -ENOTBLK; + + for (m = 1, map++; m < bp->b_map_count - 1; m++, map++) + if (BBTOB(map->bm_bn | map->bm_len) & page_align_mask) + return -ENOTBLK; + } + if (flags & XBF_READ_AHEAD) gfp_mask |= __GFP_NORETRY; else @@ -480,6 +498,7 @@ xfs_buf_alloc_direct_pages( } /* Map in the xfile pages. */ + first_page_offset = offset_in_page(BBTOB(xfs_buf_daddr(bp))); for (m = 0, p = 0, map = bp->b_maps; m < bp->b_map_count; m++, map++) { for (n = 0; n < map->bm_len; n += BTOBB(PAGE_SIZE)) { unsigned int len; @@ -502,6 +521,7 @@ xfs_buf_alloc_direct_pages( } bp->b_flags |= _XBF_DIRECT_MAP; + bp->b_offset = first_page_offset; return 0; fail: @@ -540,7 +560,7 @@ _xfs_buf_map_pages( if (bp->b_page_count == 1) { /* A single page buffer is always mappable */ - bp->b_addr = page_address(bp->b_pages[0]); + bp->b_addr = page_address(bp->b_pages[0]) + bp->b_offset; } else if (flags & XBF_UNMAPPED) { bp->b_addr = NULL; } else { @@ -567,6 +587,8 @@ _xfs_buf_map_pages( if (!bp->b_addr) return -ENOMEM; + + bp->b_addr += bp->b_offset; } return 0; |