From a14234c72bf41ac96bc8c98e96e2c84b6d4bd4f2 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 6 Feb 2017 10:50:49 -0800 Subject: xfs: go straight to real allocations for direct I/O COW writes When we allocate COW fork blocks for direct I/O writes we currently first create a delayed allocation, and then convert it to a real allocation once we've got the delayed one. As there is no good reason for that this patch instead makes use call xfs_bmapi_write from the COW allocation path. The only interesting bits are a few tweaks the low-level allocator to allow for this, most notably the need to remove the call to xfs_bmap_extsize_align for the cowextsize in xfs_bmap_btalloc - for the existing convert case it's a no-op, but for the direct allocation case it would blow up our block reservation way beyond what we reserved for the transaction. Signed-off-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/xfs/xfs_reflink.c | 94 ++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 66 insertions(+), 28 deletions(-) (limited to 'fs/xfs/xfs_reflink.c') diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index 219bc96bfc71..9bba084c1436 100644 --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -389,62 +389,100 @@ __xfs_reflink_allocate_cow( xfs_fileoff_t end_fsb) { struct xfs_mount *mp = ip->i_mount; - struct xfs_bmbt_irec imap; + struct xfs_bmbt_irec imap, got; struct xfs_defer_ops dfops; struct xfs_trans *tp; xfs_fsblock_t first_block; - int nimaps = 1, error; - bool shared; + int nimaps, error, lockmode; + bool shared, trimmed; + xfs_filblks_t resaligned; + xfs_extlen_t resblks; + xfs_extnum_t idx; - xfs_defer_init(&dfops, &first_block); + resaligned = xfs_aligned_fsb_count(*offset_fsb, end_fsb - *offset_fsb, + xfs_get_cowextsz_hint(ip)); + resblks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned); - error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, - XFS_TRANS_RESERVE, &tp); + error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, 0, &tp); if (error) return error; - xfs_ilock(ip, XFS_ILOCK_EXCL); + lockmode = XFS_ILOCK_EXCL; + xfs_ilock(ip, lockmode); - /* Read extent from the source file. */ - nimaps = 1; - error = xfs_bmapi_read(ip, *offset_fsb, end_fsb - *offset_fsb, - &imap, &nimaps, 0); - if (error) - goto out_unlock; - ASSERT(nimaps == 1); + /* + * Even if the extent is not shared we might have a preallocation for + * it in the COW fork. If so use it. + */ + if (xfs_iext_lookup_extent(ip, ip->i_cowfp, *offset_fsb, &idx, &got) && + got.br_startoff <= *offset_fsb) { + /* If we have a real allocation in the COW fork we're done. */ + if (!isnullstartblock(got.br_startblock)) { + xfs_trim_extent(&got, *offset_fsb, + end_fsb - *offset_fsb); + *offset_fsb = got.br_startoff + got.br_blockcount; + goto out_trans_cancel; + } + } else { + nimaps = 1; + error = xfs_bmapi_read(ip, *offset_fsb, end_fsb - *offset_fsb, + &imap, &nimaps, 0); + if (error) + goto out_trans_cancel; + ASSERT(nimaps == 1); + + /* Trim the mapping to the nearest shared extent boundary. */ + error = xfs_reflink_trim_around_shared(ip, &imap, &shared, + &trimmed); + if (error) + goto out_trans_cancel; + + if (!shared) { + *offset_fsb = imap.br_startoff + imap.br_blockcount; + goto out_trans_cancel; + } - /* Make sure there's a CoW reservation for it. */ - error = xfs_reflink_reserve_cow(ip, &imap, &shared); + *offset_fsb = imap.br_startoff; + end_fsb = imap.br_startoff + imap.br_blockcount; + } + + error = xfs_trans_reserve_quota_nblks(tp, ip, resblks, 0, + XFS_QMOPT_RES_REGBLKS); if (error) goto out_trans_cancel; - if (!shared) { - *offset_fsb = imap.br_startoff + imap.br_blockcount; - goto out_trans_cancel; - } + xfs_trans_ijoin(tp, ip, 0); + + xfs_defer_init(&dfops, &first_block); + nimaps = 1; /* Allocate the entire reservation as unwritten blocks. */ - xfs_trans_ijoin(tp, ip, 0); - error = xfs_bmapi_write(tp, ip, imap.br_startoff, imap.br_blockcount, + error = xfs_bmapi_write(tp, ip, *offset_fsb, end_fsb - *offset_fsb, XFS_BMAPI_COWFORK | XFS_BMAPI_PREALLOC, &first_block, - XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK), - &imap, &nimaps, &dfops); + resblks, &imap, &nimaps, &dfops); if (error) - goto out_trans_cancel; + goto out_bmap_cancel; /* Finish up. */ error = xfs_defer_finish(&tp, &dfops, NULL); if (error) - goto out_trans_cancel; + goto out_bmap_cancel; error = xfs_trans_commit(tp); + if (error) + goto out_unlock; *offset_fsb = imap.br_startoff + imap.br_blockcount; + out_unlock: - xfs_iunlock(ip, XFS_ILOCK_EXCL); + xfs_iunlock(ip, lockmode); return error; -out_trans_cancel: + +out_bmap_cancel: xfs_defer_cancel(&dfops); + xfs_trans_unreserve_quota_nblks(tp, ip, (long)resblks, 0, + XFS_QMOPT_RES_REGBLKS); +out_trans_cancel: xfs_trans_cancel(tp); goto out_unlock; } -- cgit v1.2.3