From 1f08af52e7c981e9877796a2d90b0e0f08666945 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Mon, 3 Oct 2016 09:11:53 -0700 Subject: [PATCH] xfs: implement swapext for rmap filesystems Implement swapext for filesystems that have reverse mapping. Back in the reflink patches, we augmented the bmap code with a 'REMAP' flag that updates only the bmbt and doesn't touch the allocator and implemented log redo items for those two operations. Now we can rewrite extent swapping as a (looong) series of remap operations. This is far less efficient than the fork swapping method implemented in the past, so we only switch this on for rmap. Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig --- fs/xfs/libxfs/xfs_trans_space.h | 9 ++ fs/xfs/xfs_bmap_util.c | 162 +++++++++++++++++++++++++++++++- fs/xfs/xfs_trace.h | 5 + 3 files changed, 173 insertions(+), 3 deletions(-) diff --git a/fs/xfs/libxfs/xfs_trans_space.h b/fs/xfs/libxfs/xfs_trans_space.h index 41e0428d8175..7917f6e44286 100644 --- a/fs/xfs/libxfs/xfs_trans_space.h +++ b/fs/xfs/libxfs/xfs_trans_space.h @@ -21,6 +21,8 @@ /* * Components of space reservations. */ +#define XFS_MAX_CONTIG_RMAPS_PER_BLOCK(mp) \ + (((mp)->m_rmap_mxr[0]) - ((mp)->m_rmap_mnr[0])) #define XFS_MAX_CONTIG_EXTENTS_PER_BLOCK(mp) \ (((mp)->m_alloc_mxr[0]) - ((mp)->m_alloc_mnr[0])) #define XFS_EXTENTADD_SPACE_RES(mp,w) (XFS_BM_MAXLEVELS(mp,w) - 1) @@ -28,6 +30,13 @@ (((b + XFS_MAX_CONTIG_EXTENTS_PER_BLOCK(mp) - 1) / \ XFS_MAX_CONTIG_EXTENTS_PER_BLOCK(mp)) * \ XFS_EXTENTADD_SPACE_RES(mp,w)) +#define XFS_SWAP_RMAP_SPACE_RES(mp,b,w)\ + (((b + XFS_MAX_CONTIG_EXTENTS_PER_BLOCK(mp) - 1) / \ + XFS_MAX_CONTIG_EXTENTS_PER_BLOCK(mp)) * \ + XFS_EXTENTADD_SPACE_RES(mp,w) + \ + ((b + XFS_MAX_CONTIG_RMAPS_PER_BLOCK(mp) - 1) / \ + XFS_MAX_CONTIG_RMAPS_PER_BLOCK(mp)) * \ + (mp)->m_rmap_maxlevels) #define XFS_DAENTER_1B(mp,w) \ ((w) == XFS_DATA_FORK ? (mp)->m_dir_geo->fsbcount : 1) #define XFS_DAENTER_DBS(mp,w) \ diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c index b278d62b7152..552465e011ec 100644 --- a/fs/xfs/xfs_bmap_util.c +++ b/fs/xfs/xfs_bmap_util.c @@ -1580,6 +1580,13 @@ xfs_swap_extents_check_format( if (ip->i_d.di_nextents < tip->i_d.di_nextents) return -EINVAL; + /* + * If we have to use the (expensive) rmap swap method, we can + * handle any number of extents and any format. + */ + if (xfs_sb_version_hasrmapbt(&ip->i_mount->m_sb)) + return 0; + /* * if the target inode is in extent form and the temp inode is in btree * form then we will end up with the target inode in the wrong format @@ -1649,6 +1656,130 @@ xfs_swap_extent_flush( return 0; } +/* + * Move extents from one file to another, when rmap is enabled. + */ +STATIC int +xfs_swap_extent_rmap( + struct xfs_trans **tpp, + struct xfs_inode *ip, + struct xfs_inode *tip) +{ + struct xfs_bmbt_irec irec; + struct xfs_bmbt_irec uirec; + struct xfs_bmbt_irec tirec; + xfs_fileoff_t offset_fsb; + xfs_fileoff_t end_fsb; + xfs_filblks_t count_fsb; + xfs_fsblock_t firstfsb; + struct xfs_defer_ops dfops; + int error; + xfs_filblks_t ilen; + xfs_filblks_t rlen; + int nimaps; + __uint64_t tip_flags2; + + /* + * If the source file has shared blocks, we must flag the donor + * file as having shared blocks so that we get the shared-block + * rmap functions when we go to fix up the rmaps. The flags + * will be switch for reals later. + */ + tip_flags2 = tip->i_d.di_flags2; + if (ip->i_d.di_flags2 & XFS_DIFLAG2_REFLINK) + tip->i_d.di_flags2 |= XFS_DIFLAG2_REFLINK; + + offset_fsb = 0; + end_fsb = XFS_B_TO_FSB(ip->i_mount, i_size_read(VFS_I(ip))); + count_fsb = (xfs_filblks_t)(end_fsb - offset_fsb); + + while (count_fsb) { + /* Read extent from the donor file */ + nimaps = 1; + error = xfs_bmapi_read(tip, offset_fsb, count_fsb, &tirec, + &nimaps, 0); + if (error) + goto out; + ASSERT(nimaps == 1); + ASSERT(tirec.br_startblock != DELAYSTARTBLOCK); + + trace_xfs_swap_extent_rmap_remap(tip, &tirec); + ilen = tirec.br_blockcount; + + /* Unmap the old blocks in the source file. */ + while (tirec.br_blockcount) { + xfs_defer_init(&dfops, &firstfsb); + trace_xfs_swap_extent_rmap_remap_piece(tip, &tirec); + + /* Read extent from the source file */ + nimaps = 1; + error = xfs_bmapi_read(ip, tirec.br_startoff, + tirec.br_blockcount, &irec, + &nimaps, 0); + if (error) + goto out_defer; + ASSERT(nimaps == 1); + ASSERT(tirec.br_startoff == irec.br_startoff); + trace_xfs_swap_extent_rmap_remap_piece(ip, &irec); + + /* Trim the extent. */ + uirec = tirec; + uirec.br_blockcount = rlen = min_t(xfs_filblks_t, + tirec.br_blockcount, + irec.br_blockcount); + trace_xfs_swap_extent_rmap_remap_piece(tip, &uirec); + + /* Remove the mapping from the donor file. */ + error = xfs_bmap_unmap_extent((*tpp)->t_mountp, &dfops, + tip, &uirec); + if (error) + goto out_defer; + + /* Remove the mapping from the source file. */ + error = xfs_bmap_unmap_extent((*tpp)->t_mountp, &dfops, + ip, &irec); + if (error) + goto out_defer; + + /* Map the donor file's blocks into the source file. */ + error = xfs_bmap_map_extent((*tpp)->t_mountp, &dfops, + ip, &uirec); + if (error) + goto out_defer; + + /* Map the source file's blocks into the donor file. */ + error = xfs_bmap_map_extent((*tpp)->t_mountp, &dfops, + tip, &irec); + if (error) + goto out_defer; + + error = xfs_defer_finish(tpp, &dfops, ip); + if (error) + goto out_defer; + + tirec.br_startoff += rlen; + if (tirec.br_startblock != HOLESTARTBLOCK && + tirec.br_startblock != DELAYSTARTBLOCK) + tirec.br_startblock += rlen; + tirec.br_blockcount -= rlen; + } + + /* Roll on... */ + count_fsb -= ilen; + offset_fsb += ilen; + } + + tip->i_d.di_flags2 = tip_flags2; + return 0; + +out_defer: + xfs_defer_cancel(&dfops); +out: + trace_xfs_swap_extent_rmap_error(ip, error, _RET_IP_); + tip->i_d.di_flags2 = tip_flags2; + return error; +} + /* Swap the extents of two files by swapping data forks. */ STATIC int xfs_swap_extent_forks( @@ -1799,6 +1930,7 @@ xfs_swap_extents( int lock_flags; struct xfs_ifork *cowfp; __uint64_t f; + int resblks; /* * Lock the inodes against other IO, page faults and truncate to @@ -1829,7 +1961,28 @@ xfs_swap_extents( if (error) goto out_unlock; - error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp); + /* + * Extent "swapping" with rmap requires a permanent reservation and + * a block reservation because it's really just a remap operation + * performed with log redo items! + */ + if (xfs_sb_version_hasrmapbt(&mp->m_sb)) { + /* + * Conceptually this shouldn't affect the shape of either + * bmbt, but since we atomically move extents one by one, + * we reserve enough space to rebuild both trees. + */ + resblks = XFS_SWAP_RMAP_SPACE_RES(mp, + XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK), + XFS_DATA_FORK) + + XFS_SWAP_RMAP_SPACE_RES(mp, + XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK), + XFS_DATA_FORK); + error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, + 0, 0, &tp); + } else + error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, + 0, 0, &tp); if (error) goto out_unlock; @@ -1888,8 +2041,11 @@ xfs_swap_extents( src_log_flags = XFS_ILOG_CORE; target_log_flags = XFS_ILOG_CORE; - error = xfs_swap_extent_forks(tp, ip, tip, &src_log_flags, - &target_log_flags); + if (xfs_sb_version_hasrmapbt(&mp->m_sb)) + error = xfs_swap_extent_rmap(&tp, ip, tip); + else + error = xfs_swap_extent_forks(tp, ip, tip, &src_log_flags, + &target_log_flags); if (error) goto out_trans_cancel; diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h index 75bf18bc275b..2586c9c9cd91 100644 --- a/fs/xfs/xfs_trace.h +++ b/fs/xfs/xfs_trace.h @@ -3373,6 +3373,11 @@ DEFINE_INODE_EVENT(xfs_reflink_cancel_pending_cow); DEFINE_INODE_IREC_EVENT(xfs_reflink_cancel_cow); DEFINE_INODE_ERROR_EVENT(xfs_reflink_cancel_pending_cow_error); +/* rmap swapext tracepoints */ +DEFINE_INODE_IREC_EVENT(xfs_swap_extent_rmap_remap); +DEFINE_INODE_IREC_EVENT(xfs_swap_extent_rmap_remap_piece); +DEFINE_INODE_ERROR_EVENT(xfs_swap_extent_rmap_error); + #endif /* _TRACE_XFS_H */ #undef TRACE_INCLUDE_PATH